Search

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Defective CFTR leads to accumulation of dehydrated viscous mucus within the small intestine, luminal acidification and altered intestinal motility, resulting in blockage. These changes promote gut microbial dysbiosis, adversely influencing the normal proliferation and differentiation of intestinal epithelial cells. Using Illumina 16S rRNA gene sequencing and immunohistochemistry, we assessed changes in mucosa-attached microbiome and epithelial cell profile in the small intestine of CF mice and a CF patient compared to wild-type mice and non-CF humans. We found increased abundance of pro-inflammatory Escherichia and depletion of beneficial secondary bile-acid producing bacteria in the ileal mucosa-attached microbiome of CFTR-null mice. The ileal mucosa in a CF patient was dominated by a non-aeruginosa Pseudomonas species and lacked numerous beneficial anti-inflammatory and short-chain fatty acid-producing bacteria. In the ileum of both CF mice and a CF patient, the number of absorptive enterocytes, Paneth and glucagon-like peptide 1 and 2 secreting L-type enteroendocrine cells were decreased, whereas stem and goblet cell numbers were increased. These changes in mucosa-attached microbiome and epithelial cell profile suggest that microbiota-host interactions may contribute to intestinal CF disease development with implications for therapy.

info:eu-repo/semantics/published

NASA's Parker Solar Probe (PSP) mission is currently investigating the local plasma environment of the inner-heliosphere ($< $0.25$R_\odot$) using both {\em{in-situ}} and remote sensing instrumentation. Connecting signatures of microphysical particle heating and acceleration processes to macro-scale heliospheric structure requires sensitive measurements of electromagnetic fields over a large range of physical scales. The FIELDS instrument, which provides PSP with {\em{in-situ}} measurements of electromagnetic fields of the inner heliosphere and corona, includes a set of three vector magnetometers: two fluxgate magnetometers (MAGs), and a single inductively coupled search-coil magnetometer (SCM). Together, the three FIELDS magnetometers enable measurements of the local magnetic field with a bandwidth ranging from DC to 1 MHz. This manuscript reports on the development of a merged data set combining SCM and MAG (SCaM) measurements, enabling the highest fidelity data product with an optimal signal to noise ratio. On-ground characterization tests of complex instrumental responses and noise floors are discussed as well as application to the in-flight calibration of FIELDS data. The algorithm used on PSP/FIELDS to merge waveform observations from multiple sensors with optimal signal to noise characteristics is presented. In-flight analysis of calibrations and merging algorithm performance demonstrates a timing accuracy to well within the survey rate sample period of $\sim340 \mu s$.

NASA's Parker Solar Probe (PSP) mission is currently investigating the local plasma environment of the inner-heliosphere ($< $0.25$R_\odot$) using both {\em{in-situ}} and remote sensing instrumentation. Connecting signatures of microphysical particle heating and acceleration processes to macro-scale heliospheric structure requires sensitive measurements of electromagnetic fields over a large range of physical scales. The FIELDS instrument, which provides PSP with {\em{in-situ}} measurements of electromagnetic fields of the inner heliosphere and corona, includes a set of three vector magnetometers: two fluxgate magnetometers (MAGs), and a single inductively coupled search-coil magnetometer (SCM). Together, the three FIELDS magnetometers enable measurements of the local magnetic field with a bandwidth ranging from DC to 1 MHz. This manuscript reports on the development of a merged data set combining SCM and MAG (SCaM) measurements, enabling the highest fidelity data product with an optimal signal to noise ratio. On-ground characterization tests of complex instrumental responses and noise floors are discussed as well as application to the in-flight calibration of FIELDS data. The algorithm used on PSP/FIELDS to merge waveform observations from multiple sensors with optimal signal to noise characteristics is presented. In-flight analysis of calibrations and merging algorithm performance demonstrates a timing accuracy to well within the survey rate sample period of $\sim340 \mu s$.

ObjectiveHIV is associated with frontostriatal dysregulation and executive dysfunction. This study evaluated whether HIV-infected individuals evidence deficits in random number generation (RNG), which is a strategic task requiring paced, rule-guided production of digits.MethodIn total, 74 HIV+ adults and 54 seronegative comparison participants completed a comprehensive research neuropsychological battery. Participants produced a random digit sequence by avoiding any order and using numbers 1 through 10 for 100 s at a pace of 1 digit/s. Outcomes included intrusions, repetitions, seriation (1-2-3-4), and cycling (median length of gaps between repeating digits).ResultsHIV disease was associated with higher levels of seriation and cycling (ps < .05) but not intrusions or repetitions (ps > .10). Among HIV+ individuals, higher seriation was associated with neuropsychological performance including poorer auditory attention, verbal learning, and delayed memory, whereas higher cycling scores were associated with poorer delayed memory and verbal fluency (ps < .05). Higher seriation also was independently associated with self-reported declines in activities of daily living (ADLs) in the HIV+ group.ConclusionsIndividuals living with HIV disease evidence moderate difficulties in inhibiting statistically unlikely non-random sequences, which showed medium associations with higher order verbal abilities and may contribute to greater declines in everyday functioning outcomes. Future studies might examine RNG's role in health behaviors such as medical decision-making or medication adherence.

ObjectiveHIV is associated with frontostriatal dysregulation and executive dysfunction. This study evaluated whether HIV-infected individuals evidence deficits in random number generation (RNG), which is a strategic task requiring paced, rule-guided production of digits.MethodIn total, 74 HIV+ adults and 54 seronegative comparison participants completed a comprehensive research neuropsychological battery. Participants produced a random digit sequence by avoiding any order and using numbers 1 through 10 for 100 s at a pace of 1 digit/s. Outcomes included intrusions, repetitions, seriation (1-2-3-4), and cycling (median length of gaps between repeating digits).ResultsHIV disease was associated with higher levels of seriation and cycling (ps < .05) but not intrusions or repetitions (ps > .10). Among HIV+ individuals, higher seriation was associated with neuropsychological performance including poorer auditory attention, verbal learning, and delayed memory, whereas higher cycling scores were associated with poorer delayed memory and verbal fluency (ps < .05). Higher seriation also was independently associated with self-reported declines in activities of daily living (ADLs) in the HIV+ group.ConclusionsIndividuals living with HIV disease evidence moderate difficulties in inhibiting statistically unlikely non-random sequences, which showed medium associations with higher order verbal abilities and may contribute to greater declines in everyday functioning outcomes. Future studies might examine RNG's role in health behaviors such as medical decision-making or medication adherence.

There is debate as to whether the neurocognitive changes associated with HIV infection represent an acceleration of the typical aging process or more simply reflect a greater accentuated risk for age-related declines. We aimed to determine whether accelerated neurocognitive aging is observable in a sample of older HIV-infected individuals compared to age-matched seronegatives and older old (i.e., aged ≥65) seronegative adults. Participants in a cross-sectional design included 48 HIV-seronegative (O-) and 40 HIV-positive (O+) participants between the ages of 50-65 (mean ages = 55 and 56, respectively) and 40 HIV-seronegative participants aged ≥65 (OO-; mean age = 74) who were comparable for other demographics. All participants were administered a brief neurocognitive battery of attention, episodic memory, speeded executive functions, and confrontation naming (i.e., Boston Naming Test). The O+ group performed more poorly than the O- group (i.e., accentuated aging), but not differently from the OO- on digit span and initial recall of a supraspan word list, consistent with an accelerating aging profile. However, the O+ group's performance was comparable to the O- group on all other neurocognitive tests (ps > 0.05). These data partially support a model of accelerated neurocognitive aging in HIV infection, which was observed in the domain of auditory verbal attention, but not in the areas of memory, language, or speeded executive functions. Future studies should examine whether HIV-infected adults over 65 evidence accelerated aging in downstream neurocognitive domains and subsequent everyday functioning outcomes.

Structural biology and functional studies are a powerful combination to elucidate fundamental knowledge about the cystic fibrosis transmembrane conductance regulator (CFTR). Here, we discuss the latest findings, including how clinically-approved drugs restore function to mutant CFTR, leading to better clinical outcomes for people with cystic fibrosis (CF). Despite the prospect of regulatory approval of a CFTR-targeting therapy for most CF mutations, strenuous efforts are still needed to fully comprehend CFTR structure-and-function for the development of better drugs to enable people with CF to live full and active lives.

Synthetic anion transporters are active in cystic fibrosis cells, and are additive to clinically-approved drugs, suggesting new combination therapies for this lethal genetic condition., info:eu-repo/semantics/published

Prospective memory (PM) is associated with antiretroviral (ARV) adherence in HIV, but little is known about how pill burden and age might affect this association. One hundred seventeen older (≥50 years) and 82 younger (<50 years) HIV-infected adults were administered a measure of PM in the laboratory and subsequently were monitored for ARV adherence for 30 days using the Medication Event Monitoring System. In the older group, better time-based PM performance was associated with higher likelihood of adherence, irrespective of pill burden. Within the younger sample, time-based PM was positively related to adherence only in participants with lower pill burdens. Younger HIV-infected individuals with higher pill burdens may overcome the normal effects of time-based PM on adherence through compensatory medication-taking strategies, whereas suboptimal use of these strategies by younger HIV-infected individuals with lower pill burdens may heighten their risk of ARV nonadherence secondary to deficits in time-based PM.

Prospective memory (PM) is associated with antiretroviral (ARV) adherence in HIV, but little is known about how pill burden and age might affect this association. One hundred seventeen older (≥50 years) and 82 younger (<50 years) HIV-infected adults were administered a measure of PM in the laboratory and subsequently were monitored for ARV adherence for 30 days using the Medication Event Monitoring System. In the older group, better time-based PM performance was associated with higher likelihood of adherence, irrespective of pill burden. Within the younger sample, time-based PM was positively related to adherence only in participants with lower pill burdens. Younger HIV-infected individuals with higher pill burdens may overcome the normal effects of time-based PM on adherence through compensatory medication-taking strategies, whereas suboptimal use of these strategies by younger HIV-infected individuals with lower pill burdens may heighten their risk of ARV nonadherence secondary to deficits in time-based PM.

With the rising number of individuals in their 50s and 60s who are infected with HIV, concerns have emerged about possible increases in the rates of non-HIV-associated dementias. The current study examined the prevalence of mild cognitive impairment (MCI) in older HIV-infected adults, since MCI is an intermediate state between typical cognitive aging and dementia that emerges in this age range. Participants included 75 adults with HIV disease aged 50 years and older who were on combination antiretroviral therapy (cART) and had undetectable plasma viral loads and 80 demographically similar HIV-seronegative comparison subjects. Participants completed a research neuropsychological evaluation that was used to classify MCI according to the comprehensive diagnostic scheme described by Bondi et al. (J Alzheimers Dis 42:275-289, 2014). HIV-infected persons were over seven times more likely to have an MCI designation (16 %) than their seronegative counterparts (2.5 %). Within the HIV+ cohort, MCI had minimal overlap with diagnoses of asymptomatic neurocognitive impairment and was significantly associated with older age, lower Karnofsky Scale of Performance Scores, and mild difficulties performing instrumental activities of daily living (iADLs). HIV infection in older adults is associated with a notably elevated concurrent risk of MCI, which may increase the likelihood of developing non-HIV-associated dementias as this population ages further.

Ortho-Phenylene bis-ureas serve as anionophores in cells expressing halide-sensitive yellow fluorescent protein, as well as in synthetic vesicles. Activities can reach high levels, and are strongly dependent on the deliverability of the transporters., SCOPUS: ar.j, info:eu-repo/semantics/published

Synonymous single nucleotide polymorphisms (sSNPs) are considered neutral for protein function, as by definition they exchange only codons, not amino acids. We identified an sSNP that modifies the local translation speed of the cystic fibrosis transmembrane conduc-tance regulator (CFTR), leading to detrimental changes to protein stability and function. This sSNP introduces a codon pairing to a low-abundance tRNA that is particularly rare in human bronchial epithelia, but not in other human tissues, suggesting tissue-specific effects of this sSNP. Up-regulation of the tRNA cognate to the mutated codon counteracts the effects of the sSNP and rescues protein conformation and function. Our results highlight the wide-ranging impact of sSNPs, which invert the programmed local speed of mRNA translation and provide direct evidence for the central role of cellular tRNA levels in mediating the actions of sSNPs in a tissue-specific manner.

Synthetic anion transporters (anionophores) have potential as biomedical research tools and therapeutics. However, the efficient and specific delivery of these highly lipophilic molecules to a target cell membrane is non-trivial. Here, we investigate the delivery of a powerful anionophore to artificial and cell membranes using a coiled-coil-based delivery system inspired by SNARE membrane fusion proteins. Incorporation of complementary lipopeptides into the lipid membranes of liposomes and cell-sized giant unilamellar vesicles (GUVs) facilitated the delivery of a powerful anionophore into GUVs, where its anion transport activity was monitored in real time by fluorescence microscopy. Similar results were achieved using live cells engineered to express a halide-sensitive fluorophore. We conclude that coiled-coil driven membrane fusion is a highly efficient system to deliver anionophores to target cell membranes., info:eu-repo/semantics/published

Synthetic transmembrane anion transporters (anionophores) have potential as tools for biomedical research and as therapeutic agents for diseases associated with anion-channel dysfunction. However, the possibility of H+ or OH- transport by anionophores has received little attention, and an anionophore selective for Cl- over H+/OH- is currently unavailable. Here, we show that depending on anionophore acidity, many anionophores facilitate electrogenic H+ or OH- transport, potentially leading to toxicity. Nevertheless, using several liposome-membrane-based assays, we identified two newly developed small molecules that promote electrogenic Cl- transport without effectively dissipating the transmembrane pH gradient, essentially mimicking the electrogenic cationophore valinomycin. The Cl- > H+/OH- selectivity of anionophores showed a consistent positive correlation with the degree of Cl- encapsulation and a negative correlation with the acidity of hydrogen-bond donors. Our study demonstrates that a valinomycin equivalent for Cl--selective transport is achievable., info:eu-repo/semantics/published

Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especially promising activity, including deliverability, potency and persistence. Electrophysiological tests show strong effects in epithelia, close to those of natural anion channels. Toxicity assays yield negative results in three cell lines, suggesting that promotion of anion transport may not be deleterious to cells. We therefore conclude that synthetic anion carriers are realistic candidates for further investigation as treatments for cystic fibrosis., info:eu-repo/semantics/published

Transmembrane anion carriers (anionophores) have potential in biological research and medicine, provided high activities can be obtained. There is particular interest in treating cystic fibrosis (CF), a genetic illness caused by deficient anion transport. Previous work has found that anionophore designs featuring axial ureas on steroid and trans-decalin scaffolds can be especially effective. Here we show that replacement of ureas by thioureas yields substantial further enhancements. Six new bis-thioureas have been prepared and tested for Cl(-)/NO3(-) exchange in 1-palmitoyl-2-oleoylphosphatidylcholine/cholesterol large unilamellar vesicles (LUVs). The bis-thioureas are typically >10 times more effective than the corresponding ureas and are sufficiently active that transport by molecules acting singly in LUVs is readily detected. The highest activity is shown by decalin 9, which features N-(3,5-bis(trifluoromethyl)phenyl)thioureido and octyl ester substituents. A single molecule of transporter 9 in a 200 nm vesicle promotes Cl(-)/NO3(-) exchange with a half-life of 45 s and an absolute rate of 850 chloride anions per second. Weight-for-weight, this carrier is only slightly less effective than CFTR, the natural anion channel associated with CF., info:eu-repo/semantics/published

Pulmonary delivery of plasmid DNA (pDNA)/cationic liposome complexes is associated with an acute unmethylated CG dinucleotide (CpG)-mediated inflammatory response and brief duration of transgene expression. We demonstrate that retention of even a single CpG in pDNA is sufficient to elicit an inflammatory response, whereas CpG-free pDNA vectors do not. Using a CpG-free pDNA expression vector, we achieved sustained (≥56 d) in vivo transgene expression in the absence of lung inflammation.

Pulmonary delivery of plasmid DNA (pDNA)/cationic liposome complexes is associated with an acute unmethylated CG dinucleotide (CpG)-mediated inflammatory response and brief duration of transgene expression. We demonstrate that retention of even a single CpG in pDNA is sufficient to elicit an inflammatory response, whereas CpG-free pDNA vectors do not. Using a CpG-free pDNA expression vector, we achieved sustained (≥56 d) in vivo transgene expression in the absence of lung inflammation.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2003., Includes bibliographical references (p. 44)., This thesis is organized into two papers. All results are proven over an algebraically closed field of characteristic zero. Paper 1 concerns morphisms between hypersurfaces in Pn, n =/> 4. We show that if the two hypersurfaces involved in the morphism are of general type, then the morphism of hypersurfaces extends to an everywhere-defined endomorphism of Pn. A corollary is that if X [right arrow] Y is a nonconstant morphism of hypersurfaces of large dimension and large degree, then deg Y divides deg X. The main tool used to analyze morphism between hypersurfaces is an inequality of Chern classes analogous to the Hurwitz-inequality. Paper 2 is a long example. We check that every morphism from a quintic hypersurface in I4 to a nonsingular cubic hypersurface in P4 is constant. In the process, we classify morphisms froin the projective plane to nonsingular cubic threefolds., by David C. Sheppard., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2003., Includes bibliographical references (p. 44)., This thesis is organized into two papers. All results are proven over an algebraically closed field of characteristic zero. Paper 1 concerns morphisms between hypersurfaces in Pn, n =/> 4. We show that if the two hypersurfaces involved in the morphism are of general type, then the morphism of hypersurfaces extends to an everywhere-defined endomorphism of Pn. A corollary is that if X [right arrow] Y is a nonconstant morphism of hypersurfaces of large dimension and large degree, then deg Y divides deg X. The main tool used to analyze morphism between hypersurfaces is an inequality of Chern classes analogous to the Hurwitz-inequality. Paper 2 is a long example. We check that every morphism from a quintic hypersurface in I4 to a nonsingular cubic hypersurface in P4 is constant. In the process, we classify morphisms froin the projective plane to nonsingular cubic threefolds., by David C. Sheppard., Ph.D.

This report describes the testing and analysis of smoke leakage through fire doors, fire dampers, and fire stops while verifying their fire endurance meets International Maritime Organization (IMO) requirements for Class A. The report includes descriptions of the test procedures followed, the assemblies tested, and the results obtained. The purpose of this project was to develop data that the United States Coast Guard could use when addressing a regulatory discontinuity in the fire test requirements for Class A divisions. Regulation 3.3 of Chapter 11/2 of the 1974 International Convention for The Safety of Life At Sea (SOLAS) requires that Class A divisions be 'constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour fire test'. The standard fire test evaluates the passage of flame by use of a cotton wool pad. It has no provision for determining the passage of smoke. An objective of this project was also to develop a smoke leakage test protocol and to identify acceptance criteria to complement the standard IMO one hour fire tests for Class A divisions. Tests were conducted on seven (7) fire doors, two (2) fire dampers, and two (2) fire stops. All samples tested were found to pass the one hour fire test without permitting the passage of flame past the door. Two A-15 rated fire doors were tested, and both marginally failed the thermal transmission requirement for the A-15 rating. All other samples were found to meet the acceptance criteria when applicable to the sample rating. All samples permitted more leakage after the fire test than was allowed before the fire test. The report provides comparisons of leakage rates before and after the fire tests., Prepared in cooperation with Underwriters Lab., Northbrook, IL.

Images acquired by ground-based telescopes are severely degraded by atmospheric turbulence effects. New algorithms are presented for restoration with super-resolution of satellite object images from sequences of turbulence-degraded observations. Super-resolution refers to recovery of Fourier spectral components outside the optical system passband. Modern wave front sensor (WFS) can measure the optical distortions caused by the atmosphere. Such measurement can be used for (1) control of an adaptive optics (AO) system; (2) for post-processing of the uncompensated image; and (3) for a hybrid approach involving partially compensated images. This study focuses on the second of these approaches. Quantitative simulation of imaging through turbulence and WFS are used to demonstrate the performance of new super-resolving multiframe algorithms based on Bayes maximum a posteriori (MAP) criterion. The original and object images are assumed to have Poisson statistics. The resulting Poisson MAP algorithms extend the single frame version to the multiframe case. Super-resolution is demonstrated for realistic conditions. In the blind deconvolution problem, both the original image and the degradations must be derived simultaneously from the recorded images without the aid of WFS. We investigate this problem and propose a new multiframe algorithm based on Bayes maximum likelihood. Strict constraints such as positivity and finite bandwidth are incorporated using nonlinear reparameterizations. Nonlinear conjugate gradient techniques are employed along with implementation on the massively parallel IBM SP2, in order to meet the computational demands of these algorithms. Super-resolution is demonstrated for realistic circumstances. On a related subject, nonlinear interpolative vector quantization (NLIVQ) is presented as a tool for the novel application of vector quantization (VQ) to super-resolution of diffraction-limited images. The algorithm is trained on a large set of image pairs, cons

Connection and variety are the quintessential characteristics of successful urban neighborhoods – variety in places to shop, products to buy, income level of residents, and in the interests and activities of the people who populate the sidewalks. Urban variety is not the consequence of population density alone: people must be in contact with one another, if only visually, for the place to succeed. The inside must communicate with the outside. For a city to work, its people must only follow the simple epigrammatic advice of E.M. Forster – Only connect. A place which facilitates connections must propose a physical variegation: different sizes of places, polyvalent places, places diverse in age and in cost. At the scale of the dwelling, diversity necessitates an economy of material and action, through which even a relatively modest apartment can become an excellent home. Recognizing, then, these fundamentals, is it possible to apply them in such a way that a single project may provide the seed for urban growth in a misused part of a city district? And what constitutes such a seed – what components are indispensable for it to grow? How does the articulation of degrees of privacy energize the city? The question requires that the city, both general and particular, is understood.

Cross-species comparative studies are a powerful approach to understand the epithelial Cl- channel cystic fibrosis transmembrane conductance regulator (CFTR), which is defective in the genetic disease cystic fibrosis (CF). Here, we investigate the single-channel behaviour of ovine CFTR and the impact of the most common CF mutation, F508del-CFTR, using excised inside-out membrane patches from transiently transfected CHO cells. Like human CFTR, ovine CFTR formed a weakly inwardly rectifying Cl- channel regulated by PKA-dependent phosphorylation, inhibited by the open-channel blocker glibenclamide. However, for three reasons, ovine CFTR was noticeably more active than human CFTR. First, single-channel conductance was increased. Second, open probability was augmented because the frequency and duration of channel openings were increased. Third, with enhanced affinity and efficacy, ATP more strongly stimulated ovine CFTR channel gating. Consistent with these data, the CFTR modulator phloxine B failed to potentiate ovine CFTR Cl- currents. Like its impact on human CFTR, the F508del mutation caused a temperature-sensitive folding defect, which disrupted ovine CFTR protein processing and reduced membrane stability. However, the F508del mutation had reduced impact on ovine CFTR channel gating in contrast to its marked effects on human CFTR. We conclude that ovine CFTR forms a regulated Cl- channel with enhanced conductance and ATP-dependent channel gating. This phylogenetic analysis of CFTR structure and function demonstrates that subtle changes in structure have pronounced effects on channel function and the consequences of the CF mutation F508del. This article is protected by copyright. All rights reserved.