199 results on '"Maier MA"'
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2. High performance liquid chromatography as a micro-destructive technique for the identification of anthraquinone red dyestuffs in cultural heritage objects
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Careaga Valeria P., Blanco Guerrero Astrid, Siracusano Gabriela, and Maier Marta S.
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alizarin ,carminic acid ,cultural heritage ,high performance liquid chromatography ,purpurin ,Chemistry ,QD1-999 - Abstract
This article describes two of the most common natural sources of red anthraquinones that have been used since antiquity for textile dyeing and as lake pigments, namely cochineal insect and the roots of Rubia and Relbunium plants. Carminic acid is the main component of carmine, the red colorant obtained from cochineal. Alizarin and purpurin are found in the extracts of Rubia roots, but Relbunium roots contain only purpurin. These red anthraquinones have been identified in a variety of cultural heritage objects. High performance liquid chromatography with diode array detection (HPLC-DAD) is described as the most suitable analytical technique for the identification of these dyestuffs, particularly in micro-samples from textiles or pigment layers in paintings and polychrome sculptures. Finally, application of HPLC-DAD analysis to the identification of lake pigments in micro-samples of mural paintings of two eighteenth century Andean churches in Peru is described.
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- 2023
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3. Associations between Mesodinium rubrum and cryptophyte algae in the Columbia River estuary
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Peterson, TD, primary, Golda, RL, additional, Garcia, ML, additional, Li, B, additional, Maier, MA, additional, Needoba, JA, additional, and Zuber, P, additional
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- 2013
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4. Commentary on ”Spasticity or reversible muscle hypertonia?”
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Borg, J, primary, Lindberg, PG, additional, and Maier, MA, additional
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- 2011
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5. Ex-vivo-Studie zur Evaluation der Genauigkeit der Größenmessung von Harnkonkrementen im Multislice-CT
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Maier, MA, primary, Bremerich, J, additional, and Bongartz, G, additional
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- 2005
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6. Does a C3-C4 propriospinal system transmit corticospinal excitation in the primate?:An investigation in the macaque monkey
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Maier, MA, Illert, Michael, Kirkwood, Peter A, Nielsen, Jens Bo, Lemon, RN, Maier, MA, Illert, Michael, Kirkwood, Peter A, Nielsen, Jens Bo, and Lemon, RN
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- 1998
7. Antibiotic resistance in primary care in Austria - a systematic review of scientific and grey literature
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Hoffmann Kathryn, Wagner Gernot, Apfalter Petra, and Maier Manfred
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Antibiotic resistance ,primary health care ,Austria ,systematic literature review ,grey literature ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Antibiotic resistance is an increasing challenge for health care services worldwide. While up to 90% of antibiotics are being prescribed in the outpatient sector recommendations for the treatment of community-acquired infections are usually based on resistance findings from hospitalized patients. In context of the EU-project called "APRES - the appropriateness of prescribing antibiotic in primary health care in Europe with respect to antibiotic resistance" it was our aim to gain detailed information about the resistance data from Austria in both the scientific and the grey literature. Methods A systematic review was performed including scientific and grey literature published between 2000 and 2010. Inclusion and exclusion criteria were defined and the review process followed published recommendations. Results Seventeen scientific articles and 23 grey literature documents could be found. In contrast to the grey literature, the scientific publications describe only a small part of the resistance situation in the primary health care sector in Austria. Merely half of these publications contain data from the ambulatory sector exclusively but these data are older than ten years, are very heterogeneous concerning the observed time period, the number and origin of the isolates and the kind of bacteria analysed. The grey literature yields more comprehensive and up-to-date information of the content of interest. These sources are available in German only and are not easily accessible. The resistance situation described in the grey literature can be summarized as rather stable over the last two years. For Escherichia coli e.g. the highest antibiotic resistance rates can be seen with fluorochiniolones (19%) and trimethoprim/sulfamethoxazole (27%). Conclusion Comprehensive and up-to-date antibiotic resistance data of different pathogens isolated from the community level in Austria are presented. They could be found mainly in the grey literature, only few are published in peer-reviewed journals. The grey literature, therefore, is a very valuable source of relevant information. It could be speculated that the situation of published literature is similar in other countries as well.
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- 2011
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8. Development of a practical tool to measure the impact of publications on the society based on focus group discussions with scientists
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Maier Manfred, Dorner Thomas E, and Niederkrotenthaler Thomas
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Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background A 'societal impact factor' that complements the scientific impact factor would contribute to a more comprehensive evaluation of scientific research. In order to develop a practical tool for its assessment, it is important to learn about perceptions of scientists on how to measure a societal impact factor. Methods This qualitative study presents the development of a practical tool to measure the societal impact of publications based on 8 focus group discussions with 24 biomedical scientists at the Medical University Vienna between May 2008 and May 2009. Topics focused on (1) features of an ideal tool, (2) criteria that should be considered in the assessment, and (3) the identification of practical pitfalls. In an iterative exercise involving the repeated application of the drafted tool to scientific papers, criteria for the assessment were refined. A small-scale exercise to evaluate the tool in terms of its comprehensibility, relevance and practicability was conducted using questionnaires for 6 external experts in leading positions of public health, and yielded acceptable results. Results The tool developed consists of three quantitative dimensions, that is (1) the aim of a publication, (2) the efforts of the authors to translate their research results, and, if translation was accomplished, (3) (a) the size of the area where translation was accomplished (regional, national or international), (b) its status (preliminary versus permanent) and (c) the target group of the translation (individuals, subgroup of population, total population). Conclusions Focus group discussions with scientists suggested that the societal impact factor of a publication should consider the effect of the publication in a wide set of non-scientific areas, but also the motivation behind the publication, and efforts by the authors to translate their findings. The proposed tool provides some valuable insights for further research and practical applications in the topic area.
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- 2011
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9. Rapid screening of Salmonella enterica serovars Enteritidis, Hadar, Heidelberg and Typhimurium using a serologically-correlative allelotyping PCR targeting the O and H antigen alleles
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Hofacre Charles L, Lee Margie D, Liu Tongrui, Hong Yang, Maier Marie, White David G, Ayers Sherry, Wang Lihua, Berghaus Roy, and Maurer John J
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Microbiology ,QR1-502 - Abstract
Abstract Background Classical Salmonella serotyping is an expensive and time consuming process that requires implementing a battery of O and H antisera to detect 2,541 different Salmonella enterica serovars. For these reasons, we developed a rapid multiplex polymerase chain reaction (PCR)-based typing scheme to screen for the prevalent S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium. Results By analyzing the nucleotide sequences of the genes for O-antigen biosynthesis including wba operon and the central variable regions of the H1 and H2 flagellin genes in Salmonella, designated PCR primers for four multiplex PCR reactions were used to detect and differentiate Salmonella serogroups A/D1, B, C1, C2, or E1; H1 antigen types i, g, m, r or z10; and H2 antigen complexes, I: 1,2; 1,5; 1,6; 1,7 or II: e,n,x; e,n,z15. Through the detection of these antigen gene allele combinations, we were able to distinguish among S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium. The assays were useful in identifying Salmonella with O and H antigen gene alleles representing 43 distinct serovars. While the H2 multiplex could discriminate between unrelated H2 antigens, the PCR could not discern differences within the antigen complexes, 1,2; 1,5; 1,6; 1,7 or e,n,x; e,n,z15, requiring a final confirmatory PCR test in the final serovar reporting of S. enterica. Conclusion Multiplex PCR assays for detecting specific O and H antigen gene alleles can be a rapid and cost-effective alternative approach to classical serotyping for presumptive identification of S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.
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- 2008
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10. Characteristics and trends in required home care by GPs in Austria: diseases and functional status of patients
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Pichler Ingrid, Maier Manfred, Fink Waltraud, Kamenski Gustav, and Zehetmayer Sonja
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Medicine (General) ,R5-920 - Abstract
Abstract Background Almost all societies carry responsibility towards patients who require continuous medical care at home. In many health systems the general practitioner cooperates with community based services of home care and coordinates all medical and non medical activities. In Austria the general practitioner together and in cooperation with relatives of the patient and professional organisations usually takes on this task by visiting his patients. This study was carried out to identify diseases that need home care and to describe the functional profile of home care patients in eastern Austria. Methods Cross sectional observational study with 17 GP practices participating during 2 study periods in 1997 and in 2004 in eastern Austria. Each GP identified patients requiring home care and assessed their underlying diseases and functional status by filling in a questionnaire personally after an encounter. Patients in nursing homes were excluded. Statistical tests used were t-tests, contingency tables, nonparametric Wilcoxon signed rank sum test and Fisher-combination test. Results Patients with degenerative diseases of the central nervous system (65%) caused by Alzheimer's disease and cerebrovascular occlusive disease and patients with degenerative diseases of the skeletal system (53%) were the largest groups among the 198 (1997) and 261 (2004) home care cases of the 11 (1997) and 13 (2004) practices. Malignant diseases in a terminal state constituted only 5% of the cases. More than two thirds of all cases were female with an average age of 80 years. Slightly more than 70% of the patients were at least partially mobile. Conclusion Home care and home visits for patients with degenerative diseases of the central nervous and skeletal system are important elements of GP's work. Further research should therefore focus on effective methods of training and rehabilitation to better the mental and physical status of patients living in their private homes.
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- 2006
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11. Assessment of recent lake sediment conditions in the conterminous U.S.
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Nord MA, Maier MA, Bijak AL, Crane JL, and Pollard AI
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This study provides the largest sediment quality assessment of lakes in the conterminous United States (U.S.). A variety of lakes (n = 1005) were selected based on the randomized, probabilistic sampling design of the broader 2017 National Lakes Assessment study. Surficial sediment samples (0-5 cm) were collected at one representative site (generally the deepest point) for each lake (n = 969). The samples were analyzed for 16 metal(loid)s, 25 polycyclic aromatic hydrocarbons (PAHs), 53 polychlorinated biphenyl (PCB) congeners, 27 legacy pesticides and metabolites, total organic carbon, and grain size. Metal(loid)s and PAHs were widely distributed due to natural and potential anthropogenic sources, with regional variations observed for lakes in the nine ecoregions encompassing the U.S. Most sites did not have detectable PCB congeners or legacy pesticides. An integrative chemical index of mean probable effect concentration quotients, composed of seven metal(loid)s and ƩPAH
13 , was used to assess sediment quality for the estimated population of 224,916 lakes in the conterminous U.S. Nationally, 26.5 % (CI of 20-33 %) of lakes were in good condition (corresponding to predicted low incidences of toxicity to benthic organisms), 69.3 % (CI of 63-76 %) of lakes were in fair condition, and 1.8 % (CI of 0.6-3 %) of lakes were in poor condition (corresponding to predicted high incidences of sediment toxicity). Unweighted metal(loid) and ƩPAH13 concentrations were compared to lake, watershed, and land use data. Deeper lakes were significantly more contaminated (or naturally enriched) with As, Cd, Cu, Pb, Hg, Zn, and ƩPAH13 than shallow lakes. Lakes at lower elevation were also associated with more contamination (or natural enrichment) of As, Cr, Pb, Hg, Ni, Zn, and ƩPAH13 than higher elevation lakes. Greater contamination was associated with watersheds containing larger percentages of developed land. This study demonstrates an approach which can be used by others to assess sediment quality in their jurisdictions., (Copyright © 2024. Published by Elsevier B.V.)- Published
- 2024
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12. Imported Oropouche fever to Germany in a returning traveller from Cuba.
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Maier MA, Neurohr EM, Barreto-Miranda I, Gabriel M, Günther S, and Bélard S
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- 2024
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13. Local Control of Pyoderma Gangrenosum Using Human Amniotic Membrane and Transcriptome Analysis.
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Maier MA, Dennis JR, Fontenot CJ, Taylor NA, Almukhtar R, Lau FHP, and Smith AA
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Pyoderma gangrenosum (PG) is a rare, chronic, ulcerative disease characterized by non-healing wounds that worsen with debridement, a phenomenon called pathergy. No consensus regarding pathogenesis, diagnosis, or treatment exists for PG. A previous pilot study using dehydrated human amniotic/chorionic membrane (dHACM), following excisional debridement, augmented PG wound healing and allowed for subsequent wound closure through split-thickness skin grafting (STSG). In this clinical trial (NCT05120726), four patients with an established PG diagnosis were enrolled to undergo treatment with dHACM and characterize the pre- and post-treatment transcriptome profiles. RNA sequencing was used to isolate the total RNA from specimens. Genes of particular interest were quantified through real-time quantitative reverse transcription polymerase chain reaction. We observed varied changes to the local expression of inflammatory response, positive regulators of cellular proliferation, and extracellular matrix disassembly cytokines. All PG wounds produced granulation tissue following treatment and were closed using split-thickness skin grafts., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The corresponding author serves as a paid consultant for Aroa Biosurgery and is on the advisory board for Prytime Medical. Otherwise, the authors have no relevant conflicts of interest to disclose.
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- 2024
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14. Alterations of tactile and anatomical spatial representations of the hand after stroke.
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Dupin L, Gerardin E, Térémetz M, Hamdoun S, Turc G, Maier MA, Baron JC, and Lindberg PG
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- Humans, Male, Female, Middle Aged, Aged, Adult, Space Perception physiology, Touch physiology, Paresis physiopathology, Stroke physiopathology, Stroke complications, Hand physiopathology, Touch Perception physiology
- Abstract
Stroke often causes long-term motor and somatosensory impairments. Motor planning and tactile perception rely on spatial body representations. However, the link between altered spatial body representations, motor deficit and tactile spatial coding remains unclear. This study investigates the relationship between motor deficits and alterations of anatomical (body) and tactile spatial representations of the hand in 20 post-stroke patients with upper limb hemiparesis. Anatomical and tactile spatial representations were assessed from 10 targets (nails and knuckles) respectively cued verbally by their anatomical name or using tactile stimulations. Two distance metrics (hand width and finger length) and two structural measures (relative organization of targets positions and angular deviation of fingers from their physical posture) were computed and compared to clinical assessments, normative data and lesions sites. Over half of the patients had altered anatomical and/or tactile spatial representations. Metrics of tactile and anatomical representations showed common variations, where a wider hand representation was linked to more severe motor deficits. In contrast, alterations in structural measures were not concomitantly observed in tactile and anatomical representations and did not correlate with clinical assessments. Finally, a preliminary analysis showed that specific alterations in tactile structural measures were associated with dorsolateral prefrontal stroke lesions. This study reveals shared and distinct characteristics of anatomical and tactile hand spatial representations, reflecting different mechanisms that can be affected differently after stroke: metrics and location of tactile and anatomical representations were partially shared while the structural measures of tactile and anatomical representations had distinct characteristics., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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15. Increased dual-task interference during upper limb movements in stroke exceeding that found in aging - a systematic review and meta-analysis.
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Lindberg PG, AmirShemiraniha N, Krewer C, Maier MA, and Hermsdörfer J
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Objective: To determine whether dual-task interference during upper limb tasks is increased in patients after stroke compared to healthy older subjects and to compare magnitude of stroke-induced change in interference to that explained by aging., Methods: We conducted a systematic literature search in MEDLINE, CINAHL, Google Scholar and PEDro databases up to October 2023 for studies on upper limb dual-tasks in stroke and elderly healthy subjects. Eleven upper limb dual-task studies in stroke patients and 11 studies in healthy older subjects were identified and systematically reviewed. A meta-analysis was performed on seven stroke studies and on five studies in healthy older subjects that included control groups., Results: Most stroke studies investigated proximal arm movements with kinematic measures, but few studies evaluated manual dexterity. In contrast, studies in healthy older subjects used more distal (finger tapping) tasks. The meta-analysis showed that stroke patients had on average a 19% (CI 95% = 1.0-37.3) increase in dual-task interference compared to age-matched healthy controls ( Z = 2.06, p = 0.04). Older healthy subjects showed greater dual-task interference compared to younger subjects (19% greater, CI 95% = 6.5-31.2, Z = 2.98, p = 0.003)., Conclusion: Meta-analysis revealed an increase in dual-task interference during upper limb movements in stroke patients, exceeding age-related changes, supporting the presence of subclinical impairments in divided attention post-stroke that may impede motor recovery., Competing Interests: MAM and PGL have patented the method for multidimensional measurement of manual dexterity (WO2016184935A3). PL is a founding member of Dextrain company commercializing innovation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Lindberg, AmirShemiraniha, Krewer, Maier and Hermsdörfer.)
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- 2024
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16. Evaluating the oral delivery of GalNAc-conjugated siRNAs in rodents and non-human primates.
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Yu M, Qin J, Liu X, Ramsden D, Williams B, Zlatev I, Guenther D, Matsuda S, Tymon R, Darcy J, Wong C, Tsung J, Zawaneh P, Chong S, Theile CS, Taneja N, Rogers A, Liu J, Castellanos-Rizaldos E, Bond S, So K, Denoncourt J, Castoreno A, Manoharan M, Wu JT, Fitzgerald K, Maier MA, Jadhav V, and Nair JK
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- Animals, Administration, Oral, Mice, Rats, RNA Interference, Male, Biological Availability, Humans, Rats, Sprague-Dawley, Macaca fascicularis, Liver metabolism, Macaca mulatta, Acetylgalactosamine chemistry, Acetylgalactosamine metabolism, RNA, Small Interfering administration & dosage, RNA, Small Interfering pharmacokinetics, RNA, Small Interfering chemistry, RNA, Small Interfering genetics, RNA, Small Interfering metabolism
- Abstract
Oral delivery is the most widely used and convenient route of administration of medicine. However, oral administration of hydrophilic macromolecules is commonly limited by low intestinal permeability and pre-systemic degradation in the gastrointestinal (GI) tract. Overcoming some of these challenges allowed emergence of oral dosage forms of peptide-based drugs in clinical settings. Antisense oligonucleotides (ASOs) have also been investigated for oral administration but despite the recent progress, the bioavailability remains low. Given the advancement with highly potent and durable trivalent N-acetylgalactosamine (GalNAc)-conjugated small interfering RNAs (siRNAs) via subcutaneous (s.c.) injection, we explored their activities after oral administration. We report robust RNA interference (RNAi) activity of orally administrated GalNAc-siRNAs co-formulated with permeation enhancers (PEs) in rodents and non-human primates (NHPs). The relative bioavailability calculated from NHP liver exposure was <2.0% despite minimal enzymatic degradation in the GI. To investigate the impact of oligonucleotide size on oral delivery, highly specific GalNAc-conjugated single-stranded oligonucleotides known as REVERSIRs with different lengths were employed and their activities for reversal of RNAi effect were monitored. Our data suggests that intestinal permeability is highly influenced by the size of oligonucleotides. Further improvements in the potency of siRNA and PE could make oral delivery of GalNAc-siRNAs as a practical solution., (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2024
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17. Post-Stroke Impairments of Manual Dexterity and Finger Proprioception: Their Contribution to Upper Limb Activity Capacity.
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van Ravestyn C, Gerardin E, Térémetz M, Hamdoun S, Baron JC, Calvet D, Vandermeeren Y, Turc G, Maier MA, Rosso C, Mas JL, Dupin L, and Lindberg PG
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- Adult, Aged, Female, Humans, Male, Middle Aged, Motor Activity physiology, Motor Skills physiology, Paresis physiopathology, Paresis etiology, Fingers physiopathology, Fingers physiology, Proprioception physiology, Stroke physiopathology, Stroke complications, Upper Extremity physiopathology
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Background: Knowing how impaired manual dexterity and finger proprioception affect upper limb activity capacity is important for delineating targeted post-stroke interventions for upper limb recovery., Objectives: To investigate whether impaired manual dexterity and finger proprioception explain variance in post-stroke activity capacity, and whether they explain more variance than conventional clinical assessments of upper limb sensorimotor impairments., Methods: Activity capacity and hand sensorimotor impairments were assessed using clinical measures in N = 42 late subacute/chronic hemiparetic stroke patients. Dexterity was evaluated using the Dextrain Manipulandum to quantify accuracy of visuomotor finger force-tracking (N = 36), timing of rhythmic tapping (N = 36), and finger individuation (N = 24), as well as proprioception (N = 27). Stepwise multivariate and hierarchical linear regression models were used to identify impairments best explaining activity capacity., Results: Dexterity and proprioceptive components significantly increased the variance explained in activity capacity: (i) Box and Block Test was best explained by baseline tonic force during force-tracking and tapping frequency (adjusted R
2 = .51); (ii) Motor Activity Log was best explained by success rate in finger individuation (adjusted R2 = .46); (iii) Action Research Arm Test was best explained by release of finger force and proprioceptive measures (improved reaction time related to use of proprioception; adjusted R2 = .52); and (iv) Moberg Pick-Up test was best explained by proprioceptive function (adjusted R2 = .18). Models excluding dexterity and proprioception variables explained up to 19% less variance., Conclusions: Manual dexterity and finger proprioception explain unique variance in activity capacity not captured by conventional impairment measures and should be assessed when considering the underlying causes of post-stroke activity capacity limitations.URL: https://www.clinicaltrials.gov. Unique identifier: NCT03934073., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: MT, MAM, and PGL have patented the method for multidimensional measurement of manual dexterity (WO2016184935A3). MT and PGL are founding members of start-up company Dextrain (started in 2021) who owns the commercial rights. MT now works for the start-up full-time. PGL, head of the scientific board, reports no financial gain in advising the company. CR is a member of the scientific board of the company but receives no financial benefits. The other authors report no financial interests or potential conflicts of interest.- Published
- 2024
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18. Use of Flow-through Free Flaps in Head and Neck Reconstruction.
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Maier MA, Palines PA, Guidry RF, and Stalder MW
- Abstract
Background: Reconstructive obstacles in composite head and neck defects are compounded in reoperated, traumatized, irradiated, and vessel-depleted surgical fields. In cases that require multiple free flaps, recipient vessel accessibility and inset logistics become challenging. Strategic flow-through flap configurations mitigate these issues by supplying arterial inflow and venous outflow to a second flap in a contiguous fashion. This approach (1) permits the use of a singular native recipient vessel, (2) increases the reach of the vascular pedicle, avoiding the need for arteriovenous grafting, and (3) allows for a greater three-dimensional flexibility in configuring soft tissue and bony flap inset., Methods: To demonstrate this technique, we conducted a retrospective review of all head and neck reconstruction patients presenting to us from March 2019 to April 2021., Results: We present seven oncological and two traumatic patients (N = 9) who received flow-through free flaps for head and neck reconstruction. The most common flap used as the flow-through flap was the anterolateral thigh flap (N = 7), followed by the fibula flap (N = 2). Mean follow-up time was 507 days. No flap failures occurred., Conclusion: In head and neck reconstruction, the use of the flow-through principle enables uninterrupted vascular flow for two distinct free flaps in single-stage reconstruction for patients with vessel-depleted, irradiated, and/or reoperated fields. We demonstrate that flow-through flaps in the head and neck may be used successfully for a variety of cases and flaps., Competing Interests: The authors have no financial interest to declare in relation to the content of this article. This work was not supported by any funding sources. None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)
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- 2024
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19. RNA interference in the era of nucleic acid therapeutics.
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Jadhav V, Vaishnaw A, Fitzgerald K, and Maier MA
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- RNA Interference, RNA, Small Interfering genetics, RNA, Small Interfering therapeutic use, Liver, Acetylgalactosamine
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Two decades of research on RNA interference (RNAi) have transformed a breakthrough discovery in biology into a robust platform for a new class of medicines that modulate mRNA expression. Here we provide an overview of the trajectory of small-interfering RNA (siRNA) drug development, including the first approval in 2018 of a liver-targeted siRNA interference (RNAi) therapeutic in lipid nanoparticles and subsequent approvals of five more RNAi drugs, which used metabolically stable siRNAs combined with N-acetylgalactosamine ligands for conjugate-based liver delivery. We also consider the remaining challenges in the field, such as delivery to muscle, brain and other extrahepatic organs. Today's RNAi therapeutics exhibit high specificity, potency and durability, and are transitioning from applications in rare diseases to widespread, chronic conditions., (© 2024. Springer Nature America, Inc.)
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- 2024
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20. Response to the Letter to the Editor: Surgical Delay of Thoracodorsal Artery Perforator Flaps for Bilateral Autologous Breast Reconstruction.
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Allen RJ Sr and Maier MA
- Abstract
Competing Interests: The authors have no financial interest to declare in relation to the content of this article.
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- 2024
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21. Surgical Delay of Thoracodorsal Artery Perforator Flaps for Total Autologous Breast Reconstruction.
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Maier MA, Hoffman RD, Kordahi AM, Levine J, St Hilaire H, and Allen RJ Sr
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- Humans, Female, Mastectomy, Arteries, Necrosis, Perforator Flap, Breast Neoplasms, Mammaplasty
- Abstract
Background: When abdomen-based free flap reconstruction is contraindicated, the muscle-sparing thoracodorsal artery perforator (TDAP) flap may be considered for total autologous breast reconstruction. The TDAP flap is often limited by volume and is prone to distal flap necrosis. We aim to demonstrate our experience combining the delay phenomenon with TDAP flaps for total autologous breast reconstruction., Methods: Patients presenting for autologous breast reconstruction between April 2021 and August 2023 were recruited for surgically delayed TDAP flap reconstruction when abdominally based free flap reconstruction was contraindicated because of previous abdominal surgery or poor perforator anatomy. We dissected the TDAP flap except for a distal skin bridge and then reconstructed the breast 1 to 7 days later. Data included flap dimensions (in centimeters × centimeters), delay time (in days), predelay and postdelay perforator caliber (in millimeters) and flow (in centimeters per second), operative time (in minutes), hospital length of stay (in days), complications/revisions, and follow-up time (in days)., Results: Fourteen patients and 16 flaps were included in this study. Mean age and body mass index of patients were 55.9 ± 9.6 years and 30.1 ± 4.3 kg/m2, respectively. Average flap skin island length and width were 32.1 ± 3.3 cm (n = 8 flaps) and 8.8 ± 0.7 cm (n = 5 flaps), respectively. Beveled flap width reached 16.0 ± 2.2 cm (n = 3 flaps). Average time between surgical delay and reconstruction was 2.9 days, ranging from 1 to 7 days (n = 18 flaps). Mean predelay and postdelay TDAP vessel caliber and flow measured by Doppler ultrasound increased from 1.4 ± 0.3 to 1.8 ± 0.3 mm (P = 0.03) and 13.3 ± 5.2 to 43.4 ± 18.8 cm/s (P = 0.03), respectively (n = 4 flaps). Complications included 1 donor site seroma and 1 mastectomy skin flap necrosis. Follow-up ranged from 4 to 476 days (n = 17 operations)., Conclusions: We demonstrate surgically delayed TDAP flaps as a viable option for total autologous breast reconstruction. Our series of flaps demonstrated increased perforator caliber and flow and enlarged volume capabilities and had no incidences of flap necrosis., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2024
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22. Severity of Chronic Venous Insufficiency on Primary Total Knee Arthroplasty Outcomes.
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Robin KJ, Maier MA, Leslie LJ, Dasa V, Krause PC, Jones DG, and Chapple AG
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- Adult, Humans, United States, Retrospective Studies, Postoperative Complications epidemiology, Postoperative Complications etiology, Risk Factors, Patient Readmission, Arthroplasty, Replacement, Knee adverse effects, Venous Insufficiency complications, Venous Insufficiency surgery
- Abstract
Background: More than 700,000 people in the United States undergo total knee arthroplasty (TKA) each year. Chronic venous insufficiency (CVI) affects 5% to 30% of adults, sometimes resulting in leg ulceration. These CVI cases in TKAs have been associated with worse outcomes; however, we found no study differentiating CVI severity., Methods: This retrospective study analyzed TKA outcomes at one institution from 2011 to 2021 using patient-specific codes. Analyses included short-term complications (< 90 days postoperative), long-term complications (< 2 years), and CVI status (yes/no; simple/complex/unclassified). Complex CVI consisted of pain, ulceration, inflammation, and/or other complications. Revisions within 2 years and readmissions within 90 days post-TKA were assessed. Composite complications included short-term and long-term complications, revisions, and readmissions. Multivariable logistic regressions predicted complication (any/long/short) as a function of CVI status (yes/no; simple/complex) and potential confounding variables. Of 7,665 patients, 741 (9.7%) had CVI. Among CVI patients, 247 (33.3%) had simple CVI, 233 (31.4%) had complex CVI, and 261 (35.2%) had unclassified CVI., Results: There was no difference in CVI versus control in composite complications (P = .722), short-term complications (P = .786), long-term complications (P = .15), revisions (P = .964), or readmissions (P = .438) postadjustment. Composite complication rates were 14.0% without CVI, 16.7% with complex CVI, and 9.3% with simple CVI. Complication rates differed between simple and complex CVI (P = .035)., Conclusion: Overall, CVI did not affect postoperative complications versus control. Patients who have complex CVI are at higher risk for post-TKA complications compared to those who have simple CVI., (Copyright © 2023 Elsevier Inc. All rights reserved.)
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- 2023
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23. A Rare Presentation of Scurvy in a Well-Nourished Patient.
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Robin CJ, Robin KJ, Maier MA, and Stevens ES
- Abstract
Vitamin C deficiency, otherwise known as scurvy, is a rare diagnosis among populations with adequate nutritional resources. We present a 37-year-old female patient with bilateral lower extremity edema, episodic anasarca, petechiae, and easy bruising who was diagnosed with scurvy. Given the clinical presentation, a broad differential was investigated with no findings suggestive of hematologic or cardiovascular pathology. Initial laboratory studies were unremarkable. Progression of cutaneous symptoms and subsequent laboratory findings demonstrating low vitamin C levels supported a diagnosis of scurvy. Classical symptoms of scurvy include mucocutaneous petechiae, poor wound healing, ecchymosis, hyperkeratosis, corkscrew hair, gingival swelling, and bleeding gums. Following standard enteral supplementation of vitamin C, repeat vitamin C levels failed to adequately respond with the patient remaining to be symptomatic. Given a lack of insufficient nutritional intake or known systemic illness, gastrointestinal malabsorptive etiology was suspected. Though rare in the United States, scurvy should be considered in patients with manifestations of a bleeding disorder. A gastrointestinal workup may be indicated if other nutritional deficiencies are identified, or a source of inadequate intake cannot be established., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Robin et al.)
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- 2023
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24. Surgical Delay of Thoracodorsal Artery Perforator Flaps for Bilateral Autologous Breast Reconstruction.
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Hoffman RD, Maier MA, St Hilaire H, and Allen RJ Sr
- Abstract
Autologous reconstruction accounts for nearly one-quarter of all breast reconstruction cases in the United States, with the abdomen functioning as the most popular donor site. This case describes a 62-year-old woman who presented to our clinic with a remote history of estrogen receptor+/progesterone+ breast cancer and bilateral implant-based reconstruction. After grade IV capsular contracture of her left breast, she presented for autologous reconstruction. Due to her body habitus and prior belt lipectomy, deep inferior epigastric perforator flap reconstruction was contra-indicated. The thoracodorsal artery perforator (TDAP) flap is well described in the literature, and was chosen as an alternative salvage procedure to avoid latissimus harvest and the need for implants. The TDAP flap is often limited in volume and prone to distal tip necrosis, limiting its use in breast reconstruction. We have previously demonstrated the utility of the surgical delay phenomenon in improving the reliability of superficial inferior epigastric artery free flap breast reconstruction. In this case, we demonstrate the surgically delayed TDAP flap as a viable alternative to the latissimus flap with implants for bilateral total autologous breast reconstruction., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)
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- 2023
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25. Efficacy of interactive manual dexterity training after stroke: a pilot single-blinded randomized controlled trial.
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Térémetz M, Hamdoun S, Colle F, Gerardin E, Desvilles C, Carment L, Charron S, Cuenca M, Calvet D, Baron JC, Turc G, Maier MA, Rosso C, Mas JL, and Lindberg PG
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- Humans, Single-Blind Method, Prospective Studies, Recovery of Function, Treatment Outcome, Upper Extremity, Stroke complications, Stroke Rehabilitation
- Abstract
Objective: To compare the efficacy of Dextrain Manipulandum™ training of dexterity components such as force control and independent finger movements, to dose-matched conventional therapy (CT) post-stroke., Methods: A prospective, single-blind, pilot randomized clinical trial was conducted. Chronic-phase post-stroke patients with mild-to-moderate dexterity impairment (Box and Block Test (BBT) > 1) received 12 sessions of Dextrain or CT. Blinded measures were obtained before and after training and at 3-months follow-up. Primary outcome was BBT-change (after-before training). Secondary outcomes included changes in motor impairments, activity limitations and dexterity components. Corticospinal excitability and short intracortical inhibition (SICI) were measured using transcranial magnetic stimulation., Results: BBT-change after training did not differ between the Dextrain (N = 21) vs CT group (N = 21) (median [IQR] = 5[2-7] vs 4[2-7], respectively; P = 0.36). Gains in BBT were maintained at the 3-month post-training follow-up, with a non-significant trend for enhanced BBT-change in the Dextrain group (median [IQR] = 3[- 1-7.0], P = 0.06). Several secondary outcomes showed significantly larger changes in the Dextrain group: finger tracking precision (mean ± SD = 0.3 ± 0.3N vs - 0.1 ± 0.33N; P < 0.0018), independent finger movements (34.7 ± 25.1 ms vs 7.7 ± 18.5 ms, P = 0.02) and maximal finger tapping speed (8.4 ± 7.1 vs 4.5 ± 4.9, P = 0.045). At follow-up, Dextrain group showed significantly greater improvement in Motor Activity Log (median/IQR = 0.7/0.2-0.8 vs 0.2/0.1-0.6, P = 0.05). Across both groups SICI increased in patients with greater BBT-change (Rho = 0.80, P = 0.006). Comparing Dextrain subgroups with maximal grip force higher/lower than median (61.2%), BBT-change was significantly larger in patients with low vs high grip force (7.5 ± 5.6 vs 2.9 ± 2.8; respectively, P = 0.015)., Conclusions: Although immediate improvements in gross dexterity post-stroke did not significantly differ between Dextrain training and CT, our findings suggest that Dextrain enhances recovery of several dexterity components and reported hand-use, particularly when motor impairment is moderate (low initial grip force). Findings need to be confirmed in a larger trial. Trial registration ClinicalTrials.gov NCT03934073 (retrospectively registered)., (© 2023. The Author(s).)
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- 2023
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26. A tablet-based quantitative assessment of manual dexterity for detection of early psychosis.
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Le Boterff Q, Rabah A, Carment L, Bendjemaa N, Térémetz M, Alouit A, Levy A, Tanguy G, Morin V, Amado I, Cuenca M, Turc G, Maier MA, Krebs MO, and Lindberg PG
- Abstract
Background: We performed a pilot study on whether tablet-based measures of manual dexterity can provide behavioral markers for detection of first-episode psychosis (FEP), and whether cortical excitability/inhibition was altered in FEP., Methods: Behavioral and neurophysiological testing was undertaken in persons diagnosed with FEP ( N = 20), schizophrenia (SCZ, N = 20), autism spectrum disorder (ASD, N = 20), and in healthy control subjects ( N = 20). Five tablet tasks assessed different motor and cognitive functions: Finger Recognition for effector (finger) selection and mental rotation, Rhythm Tapping for temporal control, Sequence Tapping for control/memorization of motor sequences, Multi Finger Tapping for finger individuation, and Line Tracking for visuomotor control. Discrimination of FEP (from other groups) based on tablet-based measures was compared to discrimination through clinical neurological soft signs (NSS). Cortical excitability/inhibition, and cerebellar brain inhibition were assessed with transcranial magnetic stimulation., Results: Compared to controls, FEP patients showed slower reaction times and higher errors in Finger Recognition, and more variability in Rhythm Tapping. Variability in Rhythm Tapping showed highest specificity for the identification of FEP patients compared to all other groups (FEP vs. ASD/SCZ/Controls; 75% sensitivity, 90% specificity, AUC = 0.83) compared to clinical NSS (95% sensitivity, 22% specificity, AUC = 0.49). Random Forest analysis confirmed FEP discrimination vs. other groups based on dexterity variables (100% sensitivity, 85% specificity, balanced accuracy = 92%). The FEP group had reduced short-latency intra-cortical inhibition (but similar excitability) compared to controls, SCZ, and ASD. Cerebellar inhibition showed a non-significant tendency to be weaker in FEP., Conclusion: FEP patients show a distinctive pattern of dexterity impairments and weaker cortical inhibition. Easy-to-use tablet-based measures of manual dexterity capture neurological deficits in FEP and are promising markers for detection of FEP in clinical practice., Competing Interests: MT and PL own shares in Dextrain company (www.dextrain.com) which develops and commercializes solutions for measurement and rehabilitation of manual dexterity. MT, MM, and PL have a patent on the DexTrain manipulandum (WO2020070305A1) and method for evaluating manual dexterity (WO2016184935A2). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Le Boterff, Rabah, Carment, Bendjemaa, Térémetz, Alouit, Levy, Tanguy, Morin, Amado, Cuenca, Turc, Maier, Krebs and Lindberg.)
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- 2023
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27. RNAi-mediated rheostat for dynamic control of AAV-delivered transgenes.
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Subramanian M, McIninch J, Zlatev I, Schlegel MK, Kaittanis C, Nguyen T, Agarwal S, Racie T, Alvarado MA, Wassarman K, Collins TS, Chickering T, Brown CR, Schmidt K, Castoreno AB, Shulga-Morskaya S, Stamenova E, Buckowing K, Berman D, Barry JD, Bisbe A, Maier MA, Fitzgerald K, and Jadhav V
- Subjects
- RNA Interference, RNA, Small Interfering metabolism, Transgenes, RNA, Double-Stranded, Genetic Vectors genetics, Dependovirus genetics, Dependovirus metabolism, Genetic Therapy
- Abstract
Adeno-associated virus (AAV)-based gene therapy could be facilitated by the development of molecular switches to control the magnitude and timing of expression of therapeutic transgenes. RNA interference (RNAi)-based approaches hold unique potential as a clinically proven modality to pharmacologically regulate AAV gene dosage in a sequence-specific manner. We present a generalizable RNAi-based rheostat wherein hepatocyte-directed AAV transgene expression is silenced using the clinically validated modality of chemically modified small interfering RNA (siRNA) conjugates or vectorized co-expression of short hairpin RNA (shRNA). For transgene induction, we employ REVERSIR technology, a synthetic high-affinity oligonucleotide complementary to the siRNA or shRNA guide strand to reverse RNAi activity and rapidly recover transgene expression. For potential clinical development, we report potent and specific siRNA sequences that may allow selective regulation of transgenes while minimizing unintended off-target effects. Our results establish a conceptual framework for RNAi-based regulatory switches with potential for infrequent dosing in clinical settings to dynamically modulate expression of virally-delivered gene therapies., (© 2023. The Author(s).)
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- 2023
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28. Metabolically Stable Anomeric Linkages Containing GalNAc-siRNA Conjugates: An Interplay among ASGPR, Glycosidase, and RISC Pathways.
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Kandasamy P, Mori S, Matsuda S, Erande N, Datta D, Willoughby JLS, Taneja N, O'Shea J, Bisbe A, Manoharan RM, Yucius K, Nguyen T, Indrakanti R, Gupta S, Gilbert JA, Racie T, Chan A, Liu J, Hutabarat R, Nair JK, Charisse K, Maier MA, Rajeev KG, Egli M, and Manoharan M
- Subjects
- Animals, Mice, Acetylgalactosamine chemistry, Glycoside Hydrolases metabolism, Glycosides metabolism, Hepatocytes metabolism, Ligands, Asialoglycoprotein Receptor metabolism, Galactosamine, RNA, Small Interfering metabolism, RNA-Induced Silencing Complex metabolism
- Abstract
Conjugation of synthetic triantennary N -acetyl-d-galactosamine (GalNAc) to small interfering RNA (siRNA) mediates binding to the asialoglycoprotein receptor (ASGPR) on the surface of hepatocytes, facilitating liver-specific uptake and siRNA-mediated gene silencing. The natural β-glycosidic bond of the GalNAc ligand is rapidly cleaved by glycosidases in vivo. Novel GalNAc ligands with S -, and C -glycosides with both α- and β-anomeric linkages, N -glycosides with β-anomeric linkage, and the O- glycoside with α-anomeric linkage were synthesized and conjugated to siRNA either on-column during siRNA synthesis or through a high-throughput, post-synthetic method. Unlike natural GalNAc, modified ligands were resistant to glycosidase activity. The siRNAs conjugated to newly designed ligands had similar affinities for ASGPR and similar silencing activity in mice as the parent GalNAc-siRNA conjugate. These data suggest that other factors, such as protein-nucleic acid interactions and loading of the antisense strand into the RNA-induced silencing complex (RISC), are more critical to the duration of action than the stereochemistry and stability of the anomeric linkage between the GalNAc moiety of the ligand conjugated to the sense strand of the siRNA.
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- 2023
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29. Impact of Ergonomic Posture on the Chemical Exposure of Workers in the Petroleum and Chemical Industry.
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Whitehead C, Maier MA, Rao MB, Eturki M, Snawder JE, and Davis KG
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- Chemical Industry, Ergonomics, Female, Humans, Male, Methane, Posture, Sulfur Hexafluoride, Occupational Exposure, Petroleum
- Abstract
Objectives: Despite a rise in automation, workers in the petroleum refining and petrochemical manufacturing industry are potentially exposed to various chemicals through inhalation while performing routine job duties. Many factors contribute to the degree of exposure experienced in this setting. The study objective was to characterize the impact of workplace conditions, anthropometric variability, and task orientation on exposure for a simulated routine operations task., Methods: A chemical exposure laboratory simulation study was designed to evaluate the dependent variable of chemical exposure level in the breathing zone for methane and sulfur hexafluoride. The independent variables were (i) posture of the worker, (ii) worker anthropometry, (iii) process configuration, and (iv) gas density., Results: Pipe height was a significant predictor of gas concentration measured in the breathing zone when located in a position that encouraged the gas to enter the breathing zone of the worker. Worker anthropometry had a major impact; tall worker's (male) chemical concentrations exceeded those of the short worker (female) for methane simulations but the opposite resulted for sulfur hexafluoride. Also, worker posture had a significant impact on gas exposure where nonneutral postures were found to have higher levels of chemical concentration., Conclusions: The study findings indicate that the breathing zone location is altered by posture and worker height, which changes the exposures relative to the emission source depending on the gas density of the chemicals that are present. As a result, qualitative risk assessment cannot be performed accurately without accounting for these factors. Practically, controls may need to account for worker size differences and posture adaptations., (Published by Oxford University Press on behalf of The British Occupational Hygiene Society 2022.)
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- 2022
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30. Expanding RNAi therapeutics to extrahepatic tissues with lipophilic conjugates.
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Brown KM, Nair JK, Janas MM, Anglero-Rodriguez YI, Dang LTH, Peng H, Theile CS, Castellanos-Rizaldos E, Brown C, Foster D, Kurz J, Allen J, Maganti R, Li J, Matsuda S, Stricos M, Chickering T, Jung M, Wassarman K, Rollins J, Woods L, Kelin A, Guenther DC, Mobley MW, Petrulis J, McDougall R, Racie T, Bombardier J, Cha D, Agarwal S, Johnson L, Jiang Y, Lentini S, Gilbert J, Nguyen T, Chigas S, LeBlanc S, Poreci U, Kasper A, Rogers AB, Chong S, Davis W, Sutherland JE, Castoreno A, Milstein S, Schlegel MK, Zlatev I, Charisse K, Keating M, Manoharan M, Fitzgerald K, Wu JT, Maier MA, and Jadhav V
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- Animals, Mice, Primates genetics, Primates metabolism, RNA Interference, RNA, Small Interfering genetics, RNA, Small Interfering therapeutic use, Amyloid beta-Protein Precursor, RNAi Therapeutics
- Abstract
Therapeutics based on short interfering RNAs (siRNAs) delivered to hepatocytes have been approved, but new delivery solutions are needed to target additional organs. Here we show that conjugation of 2'-O-hexadecyl (C16) to siRNAs enables safe, potent and durable silencing in the central nervous system (CNS), eye and lung in rodents and non-human primates with broad cell type specificity. We show that intrathecally or intracerebroventricularly delivered C16-siRNAs were active across CNS regions and cell types, with sustained RNA interference (RNAi) activity for at least 3 months. Similarly, intravitreal administration to the eye or intranasal administration to the lung resulted in a potent and durable knockdown. The preclinical efficacy of an siRNA targeting the amyloid precursor protein was evaluated through intracerebroventricular dosing in a mouse model of Alzheimer's disease, resulting in amelioration of physiological and behavioral deficits. Altogether, C16 conjugation of siRNAs has the potential for safe therapeutic silencing of target genes outside the liver with infrequent dosing., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)
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- 2022
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31. Age- and task-dependent effects of cerebellar tDCS on manual dexterity and motor learning-A preliminary study.
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Lindberg PG, Verneau M, Boterff QL, Cuenca-Maia M, Baron JC, and Maier MA
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- Humans, Aged, Cerebellum physiology, Learning physiology, Fingers, Movement, Transcranial Direct Current Stimulation methods
- Abstract
Objectives: The role of the cerebellum in motor learning of dexterous control and interaction with aging remains incompletely understood. We compared the effect of age and cerebellar transcranial direct current stimulation (CRB-tDCS) on motor learning in two different manual dexterity tasks, visuomotor force control vs. effector selection (independent finger movements)., Methods: Twenty younger and 20 older adults were randomized (double-blinded) to anodal or sham CRB-tDCS during dexterity training over three consecutive days, and followed-up at day 10. Motor learning was measured as (i) overall learning (across 10 days), (ii) within-day (short-term) learning, (iii) between-day learning (consolidation), and (iv) retention (long-term learning; day 3 to day 10)., Results: Younger and older subjects showed significant overall learning in both tasks. Subjects with poor initial performance showed stronger learning. No effects of CRB-tDCS were observed in younger adults. A significant Age*CRB-tDCS interaction showed that CRB-tDCS improved within-day learning in finger independence (improved reaction time in effector selection) in older adults. However, a significant Age*CRB-tDCS interaction showed that CRB-tDCS impacted consolidation negatively in older subjects. No stimulation effects were found on retention. Finally, we found that degree of within-day learning in finger independence (change in reaction times) correlated with baseline (pre-training) reaction times in both young and old subjects., Discussion: The results suggest that CRB-tDCS may improve short-term learning of manual dexterity in older adults in a task-dependent manner, specifically in difficult tasks requiring effector (action) selection. However, cerebellar tDCS stimulation may also interfere with consolidation in older subjects. These results need confirmation in a larger sample., Competing Interests: Declaration of Competing Interest MAM and PGL have patented a method for measurement of manual dexterity (EP2659835A1). MV, QLB, MC, and JCB declare no competing interests., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)
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- 2022
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32. Motor inhibition and its contribution to recovery of dexterous hand use after stroke.
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Plantin J, Godbolt AK, Pennati GV, Laurencikas E, Fransson P, Baron JC, Maier MA, Borg J, and Lindberg PG
- Abstract
Recovery of dexterous hand use is critical for functional outcome after stroke. Grip force recordings can inform on maximal motor output and modulatory and inhibitory cerebral functions, but how these actually contribute to recovery of dexterous hand use is unclear. This cohort study used serially assessed measures of hand kinetics to test the hypothesis that behavioural measures of motor modulation and inhibition explain dexterity recovery beyond that explained by measures of motor output alone. We also investigated the structural and functional connectivity correlates of grip force control recovery. Eighty-nine adults (median age = 54 years, 26% females) with first-ever ischaemic or haemorrhagic stroke and persistent arm and hand paresis were assessed longitudinally, at 3 weeks, and at 3 and 6 months after stroke. Kinetic measures included: maximal grip force, accuracy of precision and power grip force control, and ability to release force abruptly. Dexterous hand use was assessed clinically with the Box and Block Test and motor impairment with the upper extremity Fugl-Meyer Assessment. Structural and functional MRI was used to assess weighted corticospinal tract lesion load, voxel-based lesion symptom mapping and interhemispheric resting-state functional connectivity. Fifty-three per cent of patients had severe initial motor impairment and a majority still had residual force control impairments at 6 months. Force release at 3 weeks explained 11% additional variance of Box and Block Test outcome at 6 months, above that explained by initial scores (67%). Other kinetic measures did not explain additional variance of recovery. The predictive value of force release remained significant when controlling for corticospinal tract lesion load and clinical measures. Corticospinal tract lesion load correlated with recovery in grip force control measures. Lesions involving the parietal operculum, insular cortex, putamen and fronto-striatal tracts were also related to poorer force modulation and release. Lesions to fronto-striatal tracts explained an additional 5% of variance in force release beyond the 43% explained by corticospinal injury alone. Interhemispheric functional connectivity did not relate to force control recovery. We conclude that not only voluntary force generation but also force release (reflecting motor inhibition) are important for recovery of dexterous hand use after stroke. Although corticospinal injury is a main determinant of recovery, lesions to integrative somatosensory areas and fronto-parietal white matter (involved in motor inhibition) explain additional variance in post-stroke force release recovery. Our findings indicate that post-stroke upper limb motor impairment profiling, which is essential for targeted treatment, should consider both voluntary grasp generation and inhibition., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2022
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33. Role of a "Magic" Methyl: 2'-Deoxy-2'-α-F-2'-β- C -methyl Pyrimidine Nucleotides Modulate RNA Interference Activity through Synergy with 5'-Phosphate Mimics and Mitigation of Off-Target Effects.
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Guenther DC, Mori S, Matsuda S, Gilbert JA, Willoughby JLS, Hyde S, Bisbe A, Jiang Y, Agarwal S, Madaoui M, Janas MM, Charisse K, Maier MA, Egli M, and Manoharan M
- Subjects
- Animals, Liposomes, Mice, Models, Molecular, Nanoparticles, Nucleic Acid Conformation, Nucleosides, Nucleotides, Oligonucleotides, Phosphates, RNA Interference, RNA, Small Interfering genetics, Organophosphonates, Pyrimidine Nucleotides
- Abstract
Although 2'-deoxy-2'-α-F-2'-β- C -methyl (2'-F/Me) uridine nucleoside derivatives are a successful class of antiviral drugs, this modification had not been studied in oligonucleotides. Herein, we demonstrate the facile synthesis of 2'-F/Me-modified pyrimidine phosphoramidites and their subsequent incorporation into oligonucleotides. Despite the C3'- endo preorganization of the parent nucleoside, a single incorporation into RNA or DNA resulted in significant thermal destabilization of a duplex due to unfavorable enthalpy, likely resulting from steric effects. When located at the terminus of an oligonucleotide, the 2'-F/Me modification imparted more resistance to degradation than the corresponding 2'-fluoro nucleotides. Small interfering RNAs (siRNAs) modified at certain positions with 2'-F/Me had similar or better silencing activity than the parent siRNAs when delivered via a lipid nanoparticle formulation or as a triantennary N -acetylgalactosamine conjugate in cells and in mice. Modification in the seed region of the antisense strand at position 6 or 7 resulted in an activity equivalent to the parent in mice. Additionally, placement of the antisense strand at position 7 mitigated seed-based off-target effects in cell-based assays. When the 2'-F/Me modification was combined with 5'-vinyl phosphonate, both E and Z isomers had silencing activity comparable to the parent. In combination with other 2'-modifications such as 2'- O -methyl, the Z isomer is detrimental to silencing activity. Presumably, the equivalence of 5'-vinyl phosphonate isomers in the context of 2'-F/Me is driven by the steric and conformational features of the C -methyl-containing sugar ring. These data indicate that 2'-F/Me nucleotides are promising tools for nucleic acid-based therapeutic applications to increase potency, duration, and safety.
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- 2022
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34. From bench to bedside: Improving the clinical safety of GalNAc-siRNA conjugates using seed-pairing destabilization.
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Schlegel MK, Janas MM, Jiang Y, Barry JD, Davis W, Agarwal S, Berman D, Brown CR, Castoreno A, LeBlanc S, Liebow A, Mayo T, Milstein S, Nguyen T, Shulga-Morskaya S, Hyde S, Schofield S, Szeto J, Woods LB, Yilmaz VO, Manoharan M, Egli M, Charissé K, Sepp-Lorenzino L, Haslett P, Fitzgerald K, Jadhav V, and Maier MA
- Subjects
- Animals, Rats, RNA, Small Interfering genetics
- Abstract
Preclinical mechanistic studies have pointed towards RNA interference-mediated off-target effects as a major driver of hepatotoxicity for GalNAc-siRNA conjugates. Here, we demonstrate that a single glycol nucleic acid or 2'-5'-RNA modification can substantially reduce small interfering RNA (siRNA) seed-mediated binding to off-target transcripts while maintaining on-target activity. In siRNAs with established hepatotoxicity driven by off-target effects, these novel designs with seed-pairing destabilization, termed enhanced stabilization chemistry plus (ESC+), demonstrated a substantially improved therapeutic window in rats. In contrast, siRNAs thermally destabilized to a similar extent by the incorporation of multiple DNA nucleotides in the seed region showed little to no improvement in rat safety suggesting that factors in addition to global thermodynamics play a role in off-target mitigation. We utilized the ESC+ strategy to improve the safety of ALN-HBV, which exhibited dose-dependent, transient and asymptomatic alanine aminotransferase elevations in healthy volunteers. The redesigned ALN-HBV02 (VIR-2218) showed improved specificity with comparable on-target activity and the program was reintroduced into clinical development., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2022
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35. A novel tablet-based application for assessment of manual dexterity and its components: a reliability and validity study in healthy subjects.
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Rabah A, Le Boterff Q, Carment L, Bendjemaa N, Térémetz M, Dupin L, Cuenca M, Mas JL, Krebs MO, Maier MA, and Lindberg PG
- Subjects
- Adult, Hand, Healthy Volunteers, Humans, Middle Aged, Reproducibility of Results, Upper Extremity, Stroke
- Abstract
Background: We developed five tablet-based tasks (applications) to measure multiple components of manual dexterity., Aim: to test reliability and validity of tablet-based dexterity measures in healthy participants., Methods: Tasks included: (1) Finger recognition to assess mental rotation capacity. The subject taps with the finger indicated on a virtual hand in three orientations (reaction time, correct trials). (2) Rhythm tapping to evaluate timing of finger movements performed with, and subsequently without, an auditory cue (inter-stimulus interval). (3) Multi-finger tapping to assess independent finger movements (reaction time, correct trials, unwanted finger movements). (4) Sequence tapping to assess production and memorization of visually cued finger sequences (successful taps). (5) Line-tracking to assess movement speed and accuracy while tracking an unpredictably moving line on the screen with the fingertip (duration, error). To study inter-rater reliability, 34 healthy subjects (mean age 35 years) performed the tablet tasks twice with two raters. Relative reliability (Intra-class correlation, ICC) and absolute reliability (Standard error of measurement, SEM) were established. Task validity was evaluated in 54 healthy subjects (mean age 49 years, range: 20-78 years) by correlating tablet measures with age, clinical dexterity assessments (time taken to pick-up objects in Box and Block Test, BBT and Moberg Pick Up Test, MPUT) and with measures obtained using a finger force-sensor device., Results: Most timing measures showed excellent reliability. Poor to excellent reliability was found for correct trials across tasks, and reliability was poor for unwanted movements. Inter-session learning occurred in some measures. Age correlated with slower and more variable reaction times in finger recognition, less correct trials in multi-finger tapping, and slower line-tracking. Reaction times correlated with those obtained using a finger force-sensor device. No significant correlations between tablet measures and BBT or MPUT were found. Inter-task correlation among tablet-derived measures was weak., Conclusions: Most tablet-based dexterity measures showed good-to-excellent reliability (ICC ≥ 0.60) except for unwanted movements during multi-finger tapping. Age-related decline in performance and association with finger force-sensor measures support validity of tablet measures. Tablet-based components of dexterity complement conventional clinical dexterity assessments. Future work is required to establish measurement properties in patients with neurological and psychiatric disorders., (© 2022. The Author(s).)
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- 2022
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36. Autologous Breast Reconstruction with Bilateral Stacked Free Flaps in Massive Weight Loss Patients.
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Yoo A, Palines PA, Maier MA, Maddox SS, St Hilaire H, and Stalder MW
- Abstract
Patients with a history of massive weight loss who are undergoing autologous breast reconstruction after mastectomy represent a unique surgical challenge. Although these patients often have an abundance of excess skin, it may be difficult to acquire sufficient tissue volume for adequate reconstruction of bilateral breasts using single flap techniques due to the paucity of subcutaneous fat. Stacked flap techniques have emerged as an effective method in thinner patients with suboptimal fat distribution who desire autologous breast reconstruction. This can serve as an ideal strategy, specifically in this patient population, when it serves the dual function of providing adequate volume for bilateral breast reconstruction and the secondary benefit of removing the excess skin present after massive weight loss. In this article, we discuss surgical techniques used during two cases of bilateral stacked flap breast reconstruction in cancer patients subsequent to massive weight loss., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)
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- 2022
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37. Chirality matters: stereo-defined phosphorothioate linkages at the termini of small interfering RNAs improve pharmacology in vivo.
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Jahns H, Taneja N, Willoughby JLS, Akabane-Nakata M, Brown CR, Nguyen T, Bisbe A, Matsuda S, Hettinger M, Manoharan RM, Rajeev KG, Maier MA, Zlatev I, Charisse K, Egli M, and Manoharan M
- Subjects
- Animals, Isomerism, Mice, RNA Interference, RNA Stability, RNA, Double-Stranded, Organophosphates, RNA, Small Interfering metabolism
- Abstract
A critical challenge for the successful development of RNA interference-based therapeutics therapeutics has been the enhancement of their in vivo metabolic stability. In therapeutically relevant, fully chemically modified small interfering RNAs (siRNAs), modification of the two terminal phosphodiester linkages in each strand of the siRNA duplex with phosphorothioate (PS) is generally sufficient to protect against exonuclease degradation in vivo. Since PS linkages are chiral, we systematically studied the properties of siRNAs containing single chiral PS linkages at each strand terminus. We report an efficient and simple method to introduce chiral PS linkages and demonstrate that Rp diastereomers at the 5' end and Sp diastereomers at the 3' end of the antisense siRNA strand improved pharmacokinetic and pharmacodynamic properties in a mouse model. In silico modeling studies provide mechanistic insights into how the Rp isomer at the 5' end and Sp isomer at the 3' end of the antisense siRNA enhance Argonaute 2 (Ago2) loading and metabolic stability of siRNAs in a concerted manner., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2022
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38. Autologous Mandible Reconstruction in a Hypercoagulable Patient following Multiple Failed Free Flaps.
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Maier MA, Guidry RF, Palines PA, and Stalder MW
- Abstract
Coagulopathies affect 3% of free flap patients and are among the leading causes of free flap failure. This report describes the case of a head and neck cancer patient that experienced two remote free flap failures before successful autologous mandibular reconstruction. Following identification of an unrecognized thrombophilic state, a focused anticoagulation strategy was executed, including an intraoperative heparin drip, stringent postoperative maintenance of Factor Xa levels between 0.3 and 0.5 IU per mL, and transition to an outpatient enoxaparin regimen of 1 mg per kg twice daily for 1.5 months following surgery. Here, we demonstrate that free tissue transfer following multiple previous failed attempts in the setting of hypercoagulability remains a viable reconstructive option with close interdisciplinary collaboration, close clinical monitoring, and patient-specific antithrombotic protocols., Competing Interests: Disclosure: The authors have no financial interest to declare in relation to the content of this article. The study received no funding., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)
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- 2022
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39. Shrinking of spatial hand representation but not of objects across the lifespan.
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Dupin L, Cuenca M, Baron JC, Maier MA, and Lindberg PG
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- Adult, Aged, Body Image, Hand, Humans, Middle Aged, Space Perception, Touch, Young Adult, Longevity, Touch Perception
- Abstract
Perception and action are based on cerebral spatial representations of the body and the external world. However, spatial representations differ from the physical characteristics of body and external space (e.g., objects). It remains unclear whether these discrepancies are related to functional requirements of action and are shared between different spatial representations, indicating common brain processes. We hypothesized that distortions of spatial hand representation would be affected by age, sensorimotor practice and external space representation. We assessed hand representations using tactile and verbal localization tasks and quantified object representation in three age groups (20-79 yrs, total n = 60). Our results show significant shrinking of spatial hand representations (hand width) with age, unrelated to sensorimotor functions. No such shrinking occurred in spatial object representations despite some common characteristics with hand representations. Therefore, spatial properties of body representation partially share characteristics of object representation but also evolve independently across the lifespan., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2021. Published by Elsevier Ltd.)
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- 2022
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40. Overcoming GNA/RNA base-pairing limitations using isonucleotides improves the pharmacodynamic activity of ESC+ GalNAc-siRNAs.
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Schlegel MK, Matsuda S, Brown CR, Harp JM, Barry JD, Berman D, Castoreno A, Schofield S, Szeto J, Manoharan M, Charissé K, Egli M, and Maier MA
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- Acetylgalactosamine, Alcohol Oxidoreductases antagonists & inhibitors, Alcohol Oxidoreductases genetics, Alcohol Oxidoreductases metabolism, Animals, Base Pairing, COS Cells, Chlorocebus aethiops, Dimethylformamide analogs & derivatives, Dimethylformamide chemistry, Ethylamines chemistry, Female, Hepatocytes cytology, Hepatocytes metabolism, Hydrogen Bonding, Mice, Mice, Inbred C57BL, Oligoribonucleotides genetics, Oligoribonucleotides metabolism, Organophosphorus Compounds chemistry, Prealbumin antagonists & inhibitors, Prealbumin genetics, Prealbumin metabolism, Primary Cell Culture, RNA Stability, RNA, Double-Stranded genetics, RNA, Double-Stranded metabolism, RNA, Small Interfering genetics, RNA, Small Interfering metabolism, Adenosine chemistry, Cytidine chemistry, Glycols chemistry, Guanosine chemistry, Oligoribonucleotides chemistry, RNA, Double-Stranded chemistry, RNA, Small Interfering chemistry
- Abstract
We recently reported that RNAi-mediated off-target effects are important drivers of the hepatotoxicity observed for a subset of GalNAc-siRNA conjugates in rodents, and that these findings could be mitigated by seed-pairing destabilization using a single GNA nucleotide placed within the seed region of the guide strand. Here, we report further investigation of the unique and poorly understood GNA/RNA cross-pairing behavior to better inform GNA-containing siRNA design. A reexamination of published GNA homoduplex crystal structures, along with a novel structure containing a single (S)-GNA-A residue in duplex RNA, indicated that GNA nucleotides universally adopt a rotated nucleobase orientation within all duplex contexts. Such an orientation strongly affects GNA-C and GNA-G but not GNA-A or GNA-T pairing in GNA/RNA heteroduplexes. Transposition of the hydrogen-bond donor/acceptor pairs using the novel (S)-GNA-isocytidine and -isoguanosine nucleotides could rescue productive base-pairing with the complementary G or C ribonucleotides, respectively. GalNAc-siRNAs containing these GNA isonucleotides showed an improved in vitro activity, a similar improvement in off-target profile, and maintained in vivo activity and guide strand liver levels more consistent with the parent siRNAs than those modified with isomeric GNA-C or -G, thereby expanding our toolbox for the design of siRNAs with minimized off-target activity., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2021
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41. Development of current ambient background threshold values for sediment quality parameters in U.S. lakes on a regional and statewide basis.
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Crane JL, Bijak AL, Maier MA, and Nord MA
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- Environmental Monitoring, Geologic Sediments, Lakes analysis, United States, Polycyclic Aromatic Hydrocarbons analysis, Water Pollutants, Chemical analysis
- Abstract
For the first time, background threshold values have been developed for a large suite of sediment quality parameters from 969 lakes spanning the conterminous United States (U.S.). These values provide a statistical basis for estimating current ambient background, which refers to chemical and physical (e.g., grain size) concentrations derived from natural and/or widespread diffuse anthropogenic sources (e.g., nonpoint sources like atmospheric deposition and land runoff). Surficial sediment quality data, collected based on the randomized, probability-based sampling design of the 2017 National Lakes Assessment (NLA) study, were utilized for this effort. These data included 16 metal(loid)s, 25 polycyclic aromatic hydrocarbons (PAHs), 53 polychlorinated biphenyl (PCB) congeners, 27 legacy organochlorine pesticides and metabolites, total organic carbon (TOC), and grain size parameters. The data were analyzed based on different geographic areas, including: 10 U.S. Environmental Protection Agency (EPA) Regions, two major ecoregions bisecting the State of Minnesota (i.e., Temperate Plains and Upper Midwest), and for Minnesota. Hypothesis testing of 47 sediment quality parameters was performed on three geographic areas bisecting Minnesota, and there were many statistically significant (p < 0.05) differences between geographic pairs that included Minnesota. Background threshold values were calculated for parameters with >20% detects using 95% one-sided upper tolerance limit (UTL) with 95% coverage (UTL95-95) values. The UTL95-95 represents the value below which 95% of the population values are expected to fall with 95% confidence. These values were compared to matching sediment quality guidelines for the protection of benthic organisms, both with and without potential outliers removed. Applications and limitations of the UTL95-95 values are discussed. Jurisdictions within the continental U.S. could use these same publicly available sediment quality data to calculate UTL95-95 values for specific geographic areas, and other countries could design similar probabilistic field studies to determine current ambient background of sediment quality parameters in lake sediments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The views expressed herein are those of the authors and do not necessarily represent the views or policies of the U.S. EPA. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2021
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42. Small circular interfering RNAs (sciRNAs) as a potent therapeutic platform for gene-silencing.
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Jahns H, Degaonkar R, Podbevsek P, Gupta S, Bisbe A, Aluri K, Szeto J, Kumar P, LeBlanc S, Racie T, Brown CR, Castoreno A, Guenther DC, Jadhav V, Maier MA, Plavec J, Egli M, Manoharan M, and Zlatev I
- Subjects
- Animals, Female, Mice, Mice, Inbred C57BL, Gene Silencing, RNA Interference, RNA, Circular, RNA, Small Interfering
- Abstract
In order to achieve efficient therapeutic post-transcriptional gene-silencing mediated by the RNA interference (RNAi) pathway, small interfering RNAs (siRNAs) must be chemically modified. Several supra-RNA structures, with the potential to stabilize siRNAs metabolically have been evaluated for their ability to induce gene silencing, but all have limitations or have not been explored in therapeutically relevant contexts. Covalently closed circular RNA transcripts are prevalent in eukaryotes and have potential as biomarkers and disease targets, and circular RNA mimics are being explored for use as therapies. Here we report the synthesis and evaluation of small circular interfering RNAs (sciRNAs). To synthesize sciRNAs, a sense strand functionalized with the trivalent N-acetylgalactosamine (GalNAc) ligand and cyclized using 'click' chemistry was annealed to an antisense strand. This strategy was used for synthesis of small circles, but could also be used for synthesis of larger circular RNA mimics. We evaluated various sciRNA designs in vitro and in vivo. We observed improved metabolic stability of the sense strand upon circularization and off-target effects were eliminated. The 5'-(E)-vinylphosphonate modification of the antisense strand resulted in GalNAc-sciRNAs that are potent in vivo at therapeutically relevant doses. Physicochemical studies and NMR-based structural analysis, together with molecular modeling studies, shed light on the interactions of this novel class of siRNAs, which have a partial duplex character, with the RNAi machinery., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2021
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43. Centyrin ligands for extrahepatic delivery of siRNA.
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Klein D, Goldberg S, Theile CS, Dambra R, Haskell K, Kuhar E, Lin T, Parmar R, Manoharan M, Richter M, Wu M, Mendrola Zarazowski J, Jadhav V, Maier MA, Sepp-Lorenzino L, O'Neil K, and Dudkin V
- Subjects
- Animals, Cell Line, Tumor, Gene Knockdown Techniques, Gene Silencing, Genes, erbB-1, Genetic Therapy, Humans, Ligands, Mice, RNA, Messenger, RNA, Small Interfering administration & dosage, Tenascin genetics, Xenograft Model Antitumor Assays, beta Catenin genetics, Gene Transfer Techniques, RNA Interference, RNA, Small Interfering genetics
- Abstract
RNA interference (RNAi) offers the potential to treat disease at the earliest onset by selectively turning off the expression of target genes, such as intracellular oncogenes that drive cancer growth. However, the development of RNAi therapeutics as anti-cancer drugs has been limited by both a lack of efficient and target cell-specific delivery systems and the necessity to overcome numerous intracellular barriers, including serum/lysosomal instability, cell membrane impermeability, and limited endosomal escape. Here, we combine two technologies to achieve posttranscriptional gene silencing in tumor cells: Centyrins, alternative scaffold proteins binding plasma membrane receptors for targeted delivery, and small interfering RNAs (siRNAs), chemically modified for high metabolic stability and potency. An EGFR Centyrin known to internalize in EGFR-positive tumor cells was site-specifically conjugated to a beta-catenin (CTNNb1) siRNA and found to drive potent and specific target knockdown by free uptake in cell culture and in mice inoculated with A431 tumor xenografts (EGFR amplified). The generalizability of this approach was further demonstrated with Centyrins targeting multiple receptors (e.g., BCMA, PSMA, and EpCAM) and siRNAs targeting multiple genes (e.g., CD68, KLKb1, and SSB1). Moreover, by installing multiple conjugation handles, two different siRNAs were fused to a single Centyrin, and the conjugate was shown to simultaneously silence two different targets. Finally, by specifically pairing EpCAM-binding Centyrins that exhibited optimized internalization profiles, we present data showing that an EpCAM Centyrin CTNNb1 siRNA conjugate suppressed tumor cell growth of a colorectal cancer cell line containing an APC mutation but not cells with normal CTNNb1 signaling. Overall, these data demonstrate the potential of Centyrin-siRNA conjugates to target cancer cells and silence oncogenes, paving the way to a new class of anticancer drugs., Competing Interests: Declaration of interests D.K., S.G., R.D., K.H., E.K., T.L., M.R., M.W., J.M.Z., K.O., and V.D. are/were employed at Janssen while experiments were conducted. C.S.T., V.J., R.P., M.M., M.A.M., and L.S. are/were employed at Alnylam while experiments were conducted., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2021
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44. Multisensory Integration in Stroke Patients: A Theoretical Approach to Reinterpret Upper-Limb Proprioceptive Deficits and Visual Compensation.
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Bernard-Espina J, Beraneck M, Maier MA, and Tagliabue M
- Abstract
For reaching and grasping, as well as for manipulating objects, optimal hand motor control arises from the integration of multiple sources of sensory information, such as proprioception and vision. For this reason, proprioceptive deficits often observed in stroke patients have a significant impact on the integrity of motor functions. The present targeted review attempts to reanalyze previous findings about proprioceptive upper-limb deficits in stroke patients, as well as their ability to compensate for these deficits using vision. Our theoretical approach is based on two concepts: first, the description of multi-sensory integration using statistical optimization models; second, on the insight that sensory information is not only encoded in the reference frame of origin (e.g., retinal and joint space for vision and proprioception, respectively), but also in higher-order sensory spaces. Combining these two concepts within a single framework appears to account for the heterogeneity of experimental findings reported in the literature. The present analysis suggests that functional upper limb post-stroke deficits could not only be due to an impairment of the proprioceptive system per se, but also due to deficiencies of cross-references processing; that is of the ability to encode proprioceptive information in a non-joint space. The distinction between purely proprioceptive or cross-reference-related deficits can account for two experimental observations: first, one and the same patient can perform differently depending on specific proprioceptive assessments; and a given behavioral assessment results in large variability across patients. The distinction between sensory and cross-reference deficits is also supported by a targeted literature review on the relation between cerebral structure and proprioceptive function. This theoretical framework has the potential to lead to a new stratification of patients with proprioceptive deficits, and may offer a novel approach to post-stroke rehabilitation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bernard-Espina, Beraneck, Maier and Tagliabue.)
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- 2021
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45. Investigating the pharmacodynamic durability of GalNAc-siRNA conjugates.
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Brown CR, Gupta S, Qin J, Racie T, He G, Lentini S, Malone R, Yu M, Matsuda S, Shulga-Morskaya S, Nair AV, Theile CS, Schmidt K, Shahraz A, Goel V, Parmar RG, Zlatev I, Schlegel MK, Nair JK, Jayaraman M, Manoharan M, Brown D, Maier MA, and Jadhav V
- Subjects
- Acetylgalactosamine chemistry, Animals, Argonaute Proteins genetics, Asialoglycoprotein Receptor genetics, Biological Transport, Drug Stability, Female, Glycoconjugates chemistry, Glycoconjugates metabolism, Hepatocytes cytology, Hepatocytes metabolism, Humans, Hydrogen-Ion Concentration, Liver cytology, Liver metabolism, Mice, Mice, Inbred C57BL, Nanoparticles chemistry, Nanoparticles metabolism, Prealbumin antagonists & inhibitors, Prealbumin metabolism, RNA, Small Interfering genetics, Time Factors, Acetylgalactosamine metabolism, Asialoglycoprotein Receptor metabolism, Drug Carriers, Gene Silencing, Prealbumin genetics, RNA, Small Interfering metabolism
- Abstract
One hallmark of trivalent N-acetylgalactosamine (GalNAc)-conjugated siRNAs is the remarkable durability of silencing that can persist for months in preclinical species and humans. Here, we investigated the underlying biology supporting this extended duration of pharmacological activity. We found that siRNA accumulation and stability in acidic intracellular compartments is critical for long-term activity. We show that functional siRNA can be liberated from these compartments and loaded into newly generated Argonaute 2 protein complexes weeks after dosing, enabling continuous RNAi activity over time. Identical siRNAs delivered in lipid nanoparticles or as GalNAc conjugates were dose-adjusted to achieve similar knockdown, but only GalNAc-siRNAs supported an extended duration of activity, illustrating the importance of receptor-mediated siRNA trafficking in the process. Taken together, we provide several lines of evidence that acidic intracellular compartments serve as a long-term depot for GalNAc-siRNA conjugates and are the major contributor to the extended duration of activity observed in vivo., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2020
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46. Gamification as an approach to improve resilience and reduce attrition in mobile mental health interventions: A randomized controlled trial.
- Author
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Litvin S, Saunders R, Maier MA, and Lüttke S
- Subjects
- Adolescent, Adult, Anxiety psychology, Female, Humans, Male, Middle Aged, Outcome Assessment, Health Care, Resilience, Psychological, Surveys and Questionnaires, Treatment Outcome, Young Adult, Mental Health, Telemedicine, Video Games
- Abstract
Forty percent of all general-practitioner appointments are related to mental illness, although less than 35% of individuals have access to therapy and psychological care, indicating a pressing need for accessible and affordable therapy tools. The ubiquity of smartphones offers a delivery platform for such tools. Previous research suggests that gamification-turning intervention content into a game format-could increase engagement with prevention and early-stage mobile interventions. This study aimed to explore the effects of a gamified mobile mental health intervention on improvements in resilience, in comparison with active and inactive control conditions. Differences between conditions on changes in personal growth, anxiety and psychological wellbeing, as well as differences in attrition rates, were also assessed. The eQuoo app was developed and published on all leading mobile platforms. The app educates users about psychological concepts including emotional bids, generalization, and reciprocity through psychoeducation, storytelling, and gamification. In total, 358 participants completed in a 5-week, 3-armed (eQuoo, "treatment as usual" cognitive behavioral therapy journal app, no-intervention waitlist) randomized controlled trial. Relevant scales were administered to all participants on days 1, 17, and 35. Repeated-measures ANOVA revealed statistically significant increases in resilience in the test group compared with both control groups over 5 weeks. The app also significantly increased personal growth, positive relations with others, and anxiety. With 90% adherence, eQuoo retained 21% more participants than the control or waitlist groups. Intervention delivered via eQuoo significantly raised mental well-being and decreased self-reported anxiety while enhancing adherence in comparison with the control conditions. Mobile apps using gamification can be a valuable and effective platform for well-being and mental health interventions and may enhance motivation and reduce attrition. Future research should measure eQuoo's effect on anxiety with a more sensitive tool and examine the impact of eQuoo on a clinical population., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: I, Silja Litvin, am the majority shareholder of the company PsycApps Limited, which developed eQuoo, the game used in the test group for this trial. The corresponding authors have no other conflicts of interest associated with this publication, and there has been no significant financial support for this work that could have influenced its outcome. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
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- 2020
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47. Neural noise and cortical inhibition in schizophrenia.
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Carment L, Dupin L, Guedj L, Térémetz M, Cuenca M, Krebs MO, Amado I, Maier MA, and Lindberg PG
- Subjects
- Adult, Evoked Potentials, Motor physiology, Female, Humans, Male, Middle Aged, Motor Cortex physiology, Photic Stimulation methods, Transcranial Magnetic Stimulation methods, Young Adult, Electromyography methods, Hand Strength physiology, Neural Inhibition physiology, Psychomotor Performance physiology, Schizophrenia physiopathology, Schizophrenic Psychology
- Abstract
Background: Neural information processing is subject to noise and this leads to variability in neural firing and behavior. Schizophrenia has been associated with both more variable motor control and impaired cortical inhibition, which is crucial for excitatory/inhibitory balance in neural commands., Hypothesis: In this study, we hypothesized that impaired intracortical inhibition in motor cortex would contribute to task-related motor noise in schizophrenia., Methods: We measured variability of force and of electromyographic (EMG) activity in upper limb and hand muscles during a visuomotor grip force-tracking paradigm in patients with schizophrenia (N = 25), in unaffected siblings (N = 17) and in healthy control participants (N = 25). Task-dependent primary motor cortex (M1) excitability and inhibition were assessed using transcranial magnetic stimulation (TMS)., Results: During force maintenance patients with schizophrenia showed increased variability in force and EMG, despite similar mean force and EMG magnitudes. Compared to healthy controls, patients with schizophrenia also showed increased M1 excitability and reduced cortical inhibition during grip-force tracking. EMG variability and force variability correlated negatively to cortical inhibition in patients with schizophrenia. EMG variability also correlated positively to negative symptoms. Siblings had similar variability and cortical inhibition compared to controls. Increased EMG and force variability indicate enhanced motor noise in schizophrenia, which relates to reduced motor cortex inhibition., Conclusion: The findings suggest that excessive motor noise in schizophrenia may arise from an imbalance of M1 excitation/inhibition of GABAergic origin. Thus, higher motor noise may provide a useful marker of impaired cortical inhibition in schizophrenia., Competing Interests: Declaration of competing interest The authors declare that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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48. A preregistered multi-lab replication of Maier et al. (2014, Exp. 4) testing retroactive avoidance.
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Maier MA, Buechner VL, Dechamps MC, Pflitsch M, Kurzrock W, Tressoldi P, Rabeyron T, Cardeña E, Marcusson-Clavertz D, and Martsinkovskaja T
- Subjects
- Adult, Bayes Theorem, Female, Humans, Male, Young Adult, Avoidance Learning physiology, Brain physiology, Students psychology
- Abstract
The term "retroactive avoidance" refers to a special class of effects of future stimulus presentations on past behavioral responses. Specifically, it refers to the anticipatory avoidance of aversive stimuli that were unpredictable through random selection after the response. This phenomenon is supposed to challenge the common view of the arrow of time and the direction of causality. Preliminary evidence of "retroactive avoidance" has been published in mainstream psychological journals and started a heated debate about the robustness and the true existence of this effect. A series of seven experiments published in 2014 in the Journal of Consciousness Studies (Maier et al., 2014) tested the influence of randomly drawn future negative picture presentations on avoidance responses based on key presses preceding them. The final study in that series used a sophisticated quantum-based random stimulus selection procedure and implemented the most severe test of retroactive avoidance within this series. Evidence for the effect, though significant, was meager and anecdotal, Bayes factor (BF10) = 2. The research presented here represents an attempt to exactly replicate the original effect with a high-power (N = 2004) preregistered multi-lab study. The results indicate that the data favored the null effect (i.e., absence of retroactive avoidance) with a BF01 = 4.38. Given the empirical strengths of the study, namely its preregistration, multi-lab approach, high power, and Bayesian analysis used, this failed replication questions the validity and robustness of the original findings. Not reaching a decisive level of Bayesian evidence and not including skeptical researchers may be considered limitations of this study. Exploratory analyses of the change in evidence for the effect across time, performed on a post-hoc basis, revealed several potentially interesting anomalies in the data that might guide future research in this area., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
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49. Generation and validation of structurally defined antibody-siRNA conjugates.
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Nanna AR, Kel'in AV, Theile C, Pierson JM, Voo ZX, Garg A, Nair JK, Maier MA, Fitzgerald K, and Rader C
- Subjects
- Antibodies chemistry, Cell Line, Tumor, Humans, RNA, Small Interfering pharmacokinetics, beta Catenin genetics, Immunoglobulin Variable Region chemistry, RNA Interference, RNA, Small Interfering chemistry
- Abstract
Gene silencing by RNA interference (RNAi) has emerged as a powerful treatment strategy across a potentially broad range of diseases. Tailoring siRNAs to silence genes vital for cancer cell growth and function could be an effective treatment, but there are several challenges which must be overcome to enable their use as a therapeutic modality, among which efficient and selective delivery to cancer cells remains paramount. Attempts to use antibodies for siRNA delivery have been reported but these strategies use either nonspecific conjugation resulting in mixtures, or site-specific methods that require multiple steps, introduction of mutations, or use of enzymes. Here, we report a method to generate antibody-siRNA (1:2) conjugates (ARCs) that are structurally defined and easy to assemble. This ARC platform is based on engineered dual variable domain (DVD) antibodies containing a natural uniquely reactive lysine residue for site-specific conjugation to β-lactam linker-functionalized siRNA. The conjugation is efficient, does not compromise the affinity of the parental antibody, and utilizes chemically stabilized siRNA. For proof-of-concept, we generated DVD-ARCs targeting various cell surface antigens on multiple myeloma cells for the selective delivery of siRNA targeting β-catenin (CTNNB1). A set of BCMA-targeting DVD-ARCs at concentrations as low as 10 nM revealed significant CTNNB1 mRNA and protein knockdown., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)
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- 2020
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50. Common vs. Distinct Visuomotor Control Deficits in Autism Spectrum Disorder and Schizophrenia.
- Author
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Carment L, Khoury E, Dupin L, Guedj L, Bendjemaa N, Cuenca M, Maier MA, Krebs MO, Lindberg PG, and Amado I
- Subjects
- Adult, Female, Humans, Male, Phenotype, Autism Spectrum Disorder complications, Autism Spectrum Disorder physiopathology, Psychomotor Disorders complications, Psychomotor Disorders physiopathology, Schizophrenia complications, Schizophrenia physiopathology
- Abstract
Autism spectrum disorder (ASD) and schizophrenia (SCZ) are neurodevelopmental disorders with partly overlapping clinical phenotypes including sensorimotor impairments. However, direct comparative studies on sensorimotor control across these two disorders are lacking. We set out to compare visuomotor upper limb impairment, quantitatively, in ASD and SCZ. Patients with ASD (N = 24) were compared to previously published data from healthy control participants (N = 24) and patients with SCZ (N = 24). All participants performed a visuomotor grip force-tracking task in single and dual-task conditions. The dual-task (high cognitive load) presented either visual distractors or required mental addition during grip force-tracking. Motor inhibition was measured by duration of force release and from principal component analysis (PCA) of the participant's force-trajectory. Common impairments in patients with ASD and SCZ included increased force-tracking error in single-task condition compared to controls, a further increase in error in dual-task conditions, and prolonged duration of force release. These three sensorimotor impairments were found in both patient groups. In contrast, distinct impairments in patients with ASD included greater error under high cognitive load and delayed onset of force release compared to SCZ. The PCA inhibition component was higher in ASD than SCZ and controls, correlated to duration of force release, and explained group differences in tracking error. In conclusion, sensorimotor impairments related to motor inhibition are common to ASD and SCZ, but more severe in ASD, consistent with enhanced neurodevelopmental load in ASD. Furthermore, impaired motor anticipation may represent a further specific impairment in ASD. Autism Res 2020, 13: 885-896. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Autism spectrum disorder (ASD) and schizophrenia (SCZ) are neurodevelopmental disorders with partly overlapping and partly distinct clinical symptoms. Sensorimotor impairments rank among these symptoms, but it is less clear whether they are shared or distinct. In this study, we showed using a grip force task that sensorimotor impairments related to motor inhibition are common to ASD and SCZ, but more severe in ASD. Impaired motor anticipation may represent a further specific impairment in ASD., (© 2020 International Society for Autism Research, Wiley Periodicals, Inc.)
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- 2020
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