Search

• Evidence-based analysis of peri‑implant gas accumulation (PIGA). • Postoperative PIGA: common for musculoskeletal Mg implants. • Clinical relevance: potentially associated surgical complications. • Radiological techniques: for quantitative and longitudinal analysis. • Standardized evaluation needed for developing Mg implants. Historically, the rapid degradation and massive gas release from magnesium (Mg) implants resulted in severe emphysema and mechanical failure. With the advent of new alloys and surface treatment methods, optimized Mg implants have re-entered clinics since last decade with reliable performance. However, the optimization aims at slowing down the degradation process, rather than exemption of the gas release. This study involved a systematic evaluation of current preclinical and clinical evidence, regarding the physical signs, symptoms, radiological features, pathological findings and complications potentially associated with peri‑implant gas accumulation (PIGA) after musculoskeletal Mg implantation. The literature search identified 196 potentially relevant publications, and 51 papers were enrolled for further analysis, including 22 preclinical tests and 29 clinical studies published from 2005 to 2023. Various Mg-based materials have been evaluated in animal research, and the application of pure Mg and Mg alloys have been reported in clinical follow-ups involving multiple anatomical sites and musculoskeletal disorders. Soft tissue and intraosseous PIGA are common in both animal tests and clinical follow-ups, and potentially associated with certain adverse events. Radiological examinations especially micro-CT and clinical CT scans provide valuable information for quantitative and longitudinal analysis. While according to simulation tests involving Mg implantation and chemical processing, tissue fixation could lead to an increase in the volume of gas cavity, thus the results obtained from ex vivo imaging or histopathological evaluations should be interpreted with caution. There still lacks standardized procedures or consensus for both preclinical and clinical evaluation of PIGA. However, by providing focused insights into the topic, this evidence-based study will facilitate future animal tests and clinical evaluations, and support developing biocompatible Mg implants for the treatment of musculoskeletal disorders. [ABSTRACT FROM AUTHOR]

Brain maturation and neurological diseases are intricately linked to microstructural changes that inherently affect the brain's mechanical behavior. Animal models are frequently used to explore relative brain stiffness changes as a function of underlying microstructure. Here, we are using the cuprizone mouse model to study indentation-derived stiffness changes resulting from acute and chronic demyelination during a 15-week observation period. We focus on the corpus callosum, cingulum, and cortex which undergo different degrees of de- and remyelination and, therefore, result in region-specific stiffness changes. Mean stiffness of the corpus callosum starts at 1.1 ± 0.3 kPa in untreated mice, then cuprizone treatment causes stiffness to drop to 0.6 ± 0.1 kPa by week 3, temporarily increase to 0.9 ± 0.3 kPa by week 6, and ultimately stabilize around 0.7 ± 0.1 kPa by week 9 for the rest of the observation period. The cingulum starts at 3.2 ± 0.9 kPa, then drops to 1.6 ± 0.4 kPa by week 3, and then gradually stabilizes around 1.4 ± 0.3 kPa by week 9. Cortical stiffness exhibits less stiffness variations overall; it starts at 4.2 ± 1.3 kPa, drops to 2.4 ± 0.6 kPa by week 3, and stabilizes around 2.7 ± 0.9 kPa by week 6. We also assess the impact of tissue fixation on indentation-based mechanical tissue characterization. On the one hand, fixation drastically increases untreated mean tissue stiffness by a factor of 3.3 for the corpus callosum, 2.9 for the cingulum, and 3.6 for the cortex; on the other hand, fixation influences interregional stiffness ratios during demyelination, thus suggesting that fixation affects individual brain tissues differently. Lastly, we determine the spatial correlation between stiffness measurements and myelin density and observe a region-specific proportionality between myelin content and tissue stiffness. Despite extensive work, the relationship between microstructure and mechanical behavior in the brain remains mostly unknown. Additionally, the existing variation of measurement results reported in literature requires in depth investigation of the impact of individual cell and protein populations on tissue stiffness and interregional stiffness ratios. Here, we used microindentation measurements to show that brain stiffness changes with myelin density in the cuprizone-based demyelination mouse model. Moreover, we explored the impact of tissue fixation prior to mechanical characterization because of conflicting results reported in literature. We observe that fixation has a distinctly different impact on our three regions of interest, thus causing region-specific tissue stiffening and, more importantly, changing interregional stiffness ratios. [Display omitted] [ABSTRACT FROM AUTHOR]

• Immunohistochemical staining intensity is higher in adequately fixated tumor areas. • Immunohistochemical staining intensity is different within tumors, suggesting heterogeneous immunoreactivity. • Independent of tumor fixation, DNA fragments rarely exceeded a length of 300 base pairs. • The pathologist should be aware of the quality of tumor fixation during the interpretation of immunohistochemistry. The objective is to assess the impact of the quality of tissue fixation in surgical pathology on immunohistochemical (IHC) staining and DNA degradation. Twenty-five non-small cell lung cancer (NSCLC) resection specimens were analyzed. After resection, all tumors were processed according to the protocols in our center. In haematoxylin and eosin (H&E) stained tissue slides, adequately- and inadequately fixed tumor areas were microscopically demarcated, based on basement membrane detachment. In 10 IHC stains ALK (clone 5A4), PD-L (clone 22C3), CAM5.2, CK7, c-Met, KER-MNF116, NapsinA, p40, ROS1, TTF1) the immunoreactivity in H-scores was determined in adequately- and inadequately fixed, and necrotic tumor areas. From the same areas DNA was isolated, and DNA fragmentation in base pairs (bp) was measured. H-scores were significantly higher in H&E adequately fixed tumor areas in IHC stains KER-MNF116 (H-score 256 vs 15, p =0.001) and p40 (H-score 293 vs 248, p =0.028). All other stains showed a trend towards higher immunoreactivity in H&E adequately fixed areas. Independent of H&E adequatelty- or inadequately fixed areas, all IHC stains showed significant different IHC staining intensity within tumors, suggesting heterogeneous immunoreactivity (H-scores: PD-L1 123 vs 6, p = 0.001; CAM5.2 242 vs 101, p =<0.001; CK7 242 vs 128, p =<0.001; c-MET 99 vs 20, p =<0.001; KER-MNF116 281 vs 120, p =<0.001; Napsin A 268 vs 130, p = 0.005; p40 292 vs 166, p = 0.008; TTF1 199 vs 63, p =<0.001). DNA fragments rarely exceeded a length of 300 bp, independent of adequate fixation. However, DNA fragments of 300 and 400 bp had higher concentrations in tumors with short fixation delay (<6 h vs >16 h) and short fixation time (<24 h vs >24 h). Impaired tissue fixation of resected lung tumors results in decreased IHC staining intensity in some parts of the tumor. This may impact the reliability of IHC analysis. [ABSTRACT FROM AUTHOR]

A bio-integrative fiber-reinforced implant (OSSIOfiber® Hammertoe Fixation Implant, OSSIO Ltd., Caesarea, Israel) for proximal interphalangeal joint (PIPJ) correction-arthrodesis showed partial bio-integration at 1-year follow-up (1FU) in a previous study. The study was prolonged to assess the bio-integration at 2-year-follow-up (2FU). Twenty-four patients with proximal interphalangeal joint (PIPJ) correction-arthrodesis using the fiber-reinforced implant and analysed at 1FU, completed 2FU. Follow-up included clinical examination, patient reported outcomes, radiographs, MRI and bio-integration scoring. Results were compared between the 1FU and 2FU (paired t-test). Radiographs confirmed fusion in 96 % (n = 23) at 2FU (1FU, 92 % (n = 22)). Implant was no longer visible in 21 % (n = 5), partially visible in 33 % (n = 8), and fully visible in 46 % (n = 11)(1FU, fully visible 100 % (n = 24)). The border between implant and surrounding bone was scored not visible in 88 % (n = 21) and partially visible in 12 % (n = 3) (1FU, border partially visible 100 % (n = 24)). There were no cyst formation or fluid accumulation findings 1FU/2FU. Mild bone edema was detected in 4 % (n = 1) (1FU, 29 % (n = 7)). None of the edema findings were considered as adverse implant related. The mean bio-integration score was 9.71 ± 0.69 at 2FU (1FU, 7.71 ± 0.46). The parameters of border between implant and bone and bone edema further improved at the 2FU compared to the 1FU, total bio-integration score was also higher at 2FU than 1FU (each p < 0.05). This study demonstrates 96 % PIPJ fusion rate and increased bio-integration from 1FU to 2FU, reaching advanced bio-integration of the fiber-reinforced implant at 2FU. [ABSTRACT FROM AUTHOR]

Poly(l -lactic acid) (PLLA) displays simultaneous repair and regeneration properties. Therefore, it is vital for developing bone repair materials while improving their mechanical strength, and biocompatibility is essential for guaranteeing its application. In this manuscript, using solid hot drawing (SHD) technology to fabricate an oriented shish-kebab like structure, furthermore, the interface-oriented grain boundary controlled the nucleation site and cell morphology during low temperature supercritical carbon dioxide (SC-CO 2) foaming process, resulted in an oriented microcellular structure which was similar to load-bearing bone. The tensile strength, elastic modulus, and elongation at break of the oriented microcellular PLLA were 98.4 MPa, 3.3 GPa, and 16.4%, respectively. Furthermore, the biomimetic structure improved osteoblast cells (MC3T3) attachment, proliferation, and propagation. These findings may pave the way for designing novel biomaterials for bone fixation or tissue engineering devices. [ABSTRACT FROM AUTHOR]

• Wide variation in practice in the management of patients with severe open tibial fractures between UK major trauma centres (MTCs). • Overall better adherence to BOAST guidelines if directly admitted to an MTC. • Poorer KPI compliance and outcomes in those aged 65 years and older. To evaluate the management of patients with severe open tibial fractures at major trauma centres (MTCs) in the UK with respect to BOAST 4 guidelines. Data collected by the Trauma and Audit Research Network (TARN) for all severe open tibial fractures treated at the 23 adult MTCs were evaluated. Key performance indicators (KPIs) included MTC admission under orthoplastics, administration of antibiotics within three hours of injury, initial debridement within 24 h and definitive fixation and soft tissue coverage within 72 h. Outcomes included 30-day infection rate, amputation rate and mortality rate. A score was calculated according to overall attainment of KPIs, and correlated to outcomes. From 2014 to 2020, 3359 adults with Gustilo-Anderson (GA) IIIB and/or IIIC fractures were admitted to MTCs. Male to female ratio was 2:1 with a mean age of 43 and 65 years respectively. There was a negative correlation between KPI score and mortality rate (r =-0.4929, p = 0.0169). Direct admission to an MTC was positively correlated with receipt of antibiotics within three hours (r = 0.5452, p = 0.0070). Joint orthoplastic plans were documented in 89 % of patients (MTC range 30–95 %). Soft tissue cover was achieved within 72 h for 48 % (MTC range 5.23–89.39 %). Patients over 65 were significantly more likely to have a delay to MTC admission and prophylactic antibiotic administration. Mortality rate in this group was 6% vs 2 % in those under 65. The older cohort were twice as likely to require an amputation. This is the largest cohort of open tibial injuries managed in the UK with wide variation in practice between centres demonstrated and better adherence to BOAST guidelines linked to reduced mortality in those aged 65 and over. The older cohort of patients also had higher rates of infection and amputation. It is unclear whether these poor outcomes are due to the pre-morbid physiological status of the patient or non-compliance to Standards. We present these data to highlight the need for improved adherence to Standards – the adoption of a scoring system provides a simple way to evidence this. [ABSTRACT FROM AUTHOR]

[Display omitted] • Formalin fixation influences elemental content of human tissues. • K and Cl content severely decreases after two days of formalin fixation. • P uptake in the tissue due to the buffered formalin solution. Formalin fixation is a crucial step in the preparation of tissue samples for anatomic pathology studies, however, research showed that prolonged formalin fixation, can alter the elemental composition of tissues with implications for pathology and biomedical research. In this study we aim to assess and parametrize the influence of short-term formalin fixation in tissues. Six sets of human colon tissue samples were exposed to different formalin fixation times, up until 48 h. The elemental content throughout time was compared to the elemental content of the snap-frozen sample of the same tissue that was not exposed to formalin using Energy Dispersive X-ray Fluorescence. Results showed a clear decrease of Cl and K concentration in the tissues solution reaching a plateau between 1 h and 3 h of fixation. Also, there is an uptake of P in the tissue, likely due to the buffered formalin solution, within the first 15 min of fixation. This behaviour was concomitant with an increase of Na determined using Particle Induced gamma-ray emission analysis (PIGE) and Elastic Backscattering Spectroscopy (EBS). The dynamic changes determined in the studied elements demonstrate that a better understanding of the fixation-related mechanisms is in demand as well as optimization of the fixation protocols implemented in anatomic pathology laboratories. [ABSTRACT FROM AUTHOR]

Cover-all mapping of the distribution of neurons in the human brain would have a significant impact on the deep understanding of brain function. Therefore, complete knowledge of the structural organization of different human brain regions at the cellular level would allow understanding their role in the functions of specific neural networks. Recent advances in tissue clearing techniques have allowed important advances towards this goal. These methods use specific chemicals capable of dissolving lipids, making the tissue completely transparent by homogenizing the refractive index. However, labeling and clearing human brain samples is still challenging. Here, we present an approach to perform the cellular mapping of the human cerebral cortex coupling immunostaining with SWITCH/TDE clearing and confocal microscopy. A specific evaluation of the contributions of the autofluorescence signals generated from the tissue fixation is provided as well as an assessment of lipofuscin pigments interference. Our evaluation demonstrates the possibility of obtaining an efficient clearing and labeling process of parts of adult human brain slices, making it an excellent method for morphological classification and antibody validation of neuronal and non-neuronal markers. [ABSTRACT FROM AUTHOR]

Tissue fixation is a prevalent method for bone conservation. Bone biopsies are typically fixed in formalin, dehydrated in ethanol, and infiltrated with polymethyl methacrylate (PMMA) Since some experiments can only be performed on fixed bone samples, it is essential to understand how fixation affects the measured material properties. The aim of this study was to quantify the influence of tissue fixation on the mechanical properties of cortical ovine bone at the extracellular matrix (ECM) level with state-of-the-art micromechanical techniques. A small section from the middle of the diaphysis of two ovine tibias (3.5 and 5.5 years old) was cut in the middle and polished on each side, resulting in a pair of mirrored surfaces. For each pair, one specimen underwent a fixation protocol involving immersion in formalin, dehydration with ethanol, and infiltration with PMMA. The other specimen (mirrored) was air-dried. Six osteons were selected in both pairs, which could be identified in both specimens. The influence of fixation on the mechanical properties was first analyzed using micropillar compression tests and nanoindentation in dry condition. Additionally, changes in the degree of mineralization were evaluated with Raman spectroscopy in both fixed and native bone ECM. Finally, micro tensile experiments were conducted in the 3.5-year fixed ovine bone ECM and compared to reported properties of unfixed dry ovine bone ECM. Interestingly, we found that tissue fixation does not alter the mechanical properties of ovine cortical bone ECM compared to experiments in dry state. However, animal age increases the degree of mineralization (p = 0.0159) and compressive yield stress (p = 0.041). Tissue fixation appears therefore as a valid conservation technique for investigating the mechanical properties of dehydrated bone ECM. [Display omitted] • Influence of fixation on the mechanical and mineralization properties was examined in dry ovine bone extracellular matrix. • Novel micro mechanical tests were applied to compare the mechanical properties in fixed and native dry ovine bone biopsies. • Mechanical properties of fixed bone were not statistically different compared to native dry bone extracellular matrix. [ABSTRACT FROM AUTHOR]

In recent decades, due to some limitations from alumina (Al 2 O 3) and zirconia (ZrO 2), silicon nitride (Si 3 N 4) has been investigated as a novel bioceramic material, mainly in situations where a bone replacement is required. Si 3 N 4 ceramics and its derivative form, SiAlON, possess advantages in orthopedics due to their mechanical properties and biologically acceptable chemistry, which accelerates bone repair. However, biological applications require additional properties, enabling stronger chemical bonding to the surrounding tissue for better fixation and the prevention of bacteria biofilm formation. Therefore, two commercial Si 3 N 4 and SiAlON ceramics were investigated in this study and compared to each other according to their material properties (like wetting angles and surface chemistry) and their antibacterial behaviors using E. coli. Results provided evidence of a 15% reduction in E. coli colonization after just 24 h on Si 3 N 4 compared to SiAlON which is impressive considering no antibiotics were used. Further, a mechanism of action is provided. In this manner, this study provides evidence that Si 3 N 4 should be further studied for a wide range of antibacterial orthopedic, or other suitable biomaterial applications. [ABSTRACT FROM AUTHOR]

Formalin-fixed and paraffin-embedded (FFPE) tissue represents a valuable resource to examine cancer metabolic alterations and to identify potential markers of disease. Protocols commonly used for liquid-chromatography mass spectrometry (LC-MS)-based FFPE metabolomics have not been optimized for lipidomic analysis and pre-analytical factors, that potentially affect metabolite levels, were scarcely investigated. We here demonstrate the assessment and optimization of sample preparation procedures for comprehensive metabolomic and lipidomic profiling in FFPE kidney tissue by LC-QTOF-MS. The optimized protocol allows improved monitoring of lipids including ceramides (Cer), glycosphingolipids (GSL) and triglycerides (TAGs) while the profiling capability for small polar molecules is maintained. Further, repeatable sample preparation (CVs < 20%) along with high analytical (CVs < 10%) and inter-day precision (CVs < 20%) is achieved. As proof of concept, we analyzed a set of clear cell renal cell carcinoma (ccRCC) and corresponding non-tumorous FFPE tissue samples, achieving phenotypic distinction. Investigation of the impact of tissue fixation time (6 h, 30 h and 54 h) on FFPE tissue metabolic profiles revealed metabolite class-dependent differences on their detection abundance. Whereas specific lipids (e.g. phosphatidylinositoles, GSLs, saturated fatty acids and saturated lyso-phosphatidytlethanolamines [LPE]) remained largely unaffected (CVs < 20% between groups of fixation time), neutral lipids (e.g. Cer and TAGs) exhibited high variability (CVs > 80%). Strikingly, out of the lipid classes assigned as unaffected, fatty acids 18:0, 16:0 and LPE 18:0 were detectable by high-resolution MALDI-FT-ICR MS imaging in an independent cohort of ccRCC tissues (n = 64) and exhibited significant differences between tumor and non-tumor regions. Image 1 • New protocol for metabolomic and improved lipidomic profiling in FFPE kidney tissue. • Repeatable sample preparation and high inter-day precision is achieved. • Proof of concept experiment on tumorous and non-tumorous FFPE kidney tissue. • Formalin fixation time affects FFPE tissue metabolomic and lipidomic profiles. • MALDI imaging of lipids that were found to be unaffected by tissue fixation time. [ABSTRACT FROM AUTHOR]

There is no current standard by which culture specimens from revision shoulder arthroplasty should be handled, processed, cultured, and reported. Due to the relatively low numbers of cases multicenter study may provide information to form consensus recommendations. However, assimilation of multicenter data requires comparable methodologies. The objective of this study was to document and evaluate the extent of variability between surgeons and institutions. An 11-question survey was sent to 20 shoulder surgeons as part of the American Shoulder and Elbow Surgeons Periprosthetic Joint Infection Multicenter Workgroup. Questions addressed how samples are handled in the operating room by surgeons, processing of tissue samples and explants by laboratories, number of media, culture incubation durations, and culture reporting. Common practices regarding specimen handling and processing were identified including prolonged culture incubation times >13 days (94% of participants). However, substantial variation in handling of tissue and explant specimens, number and type of media used, and reporting of results were identified. The majority of surgeons reported using a sterile instrument to harvest each individual tissue specimen (10/17, 59%), more so than using any available instrument (4/17, 24%) or washing and re-using the same instrument (3/17, 18%). Half of the institutions require a time limit by which samples must be processed in the laboratory (8/16, 50%). Nine institutions (9/16, 56%) report cultures in a semiquantitative manner, while 7 (44%) report cultures in a binary fashion. Five institutions reported having performed a negative control study, and the rate of positive cultures ranged between 0% and 17%. The majority of positive cultures from the negative controls contained Cutibacterium (92%). Specimen handling, processing, culturing, and reporting varies widely between institutions. Due to the risk of false positives as demonstrated by negative control studies, surgeons should be cognizant of potential sources of contamination at the specimen handling level in the operating room and specimen processing level in the laboratory. Given the challenges in interpretation of positive cultures in revision shoulder arthroplasty, further studies are needed to determine whether assimilation of data across institutions is acceptable or whether a standard culturing methodology across institutions is necessary. Level of Evidence: V [ABSTRACT FROM AUTHOR]

Introduction: The medial patellofemoral and patellotibial ligaments (MPFL and MPTL) are the main passive restraints to lateral patellar translation. When nonoperative management of patellofemoral dislocations fails, surgical options can be considered to restore patellofemoral stability. Several reconstruction procedures of the MPFL with semitendinosus, gracilis, quadriceps tendon, and synthetic grafts have been described. No clear superiority of one surgical technique over another is evident.Materials and Methods: Patients who suffered at least two documented episodes of unilateral patellar dislocation, confirmed radiographically and at clinical examination, underwent combined MPFL and MPTL reconstruction. Patients were regularly followed-up postoperatively at 2, 4, 8, 12, and 24 weeks, and then annually for a minimum of 2.5 years. Clinical and functional evaluations were performed using the modified Cincinnati rating system and the Kujala score, while anthropometry values including thigh volume and cross-sectional area of the thigh were measured before the operation and at the latest follow-up bilaterally.Results: There were 7 males and 27 females with a mean age of 26.5 ± 10.7 years (range, 13-39 years). The mean follow-up was 3.1 years (range, 2.5-4 years). The mean modified Cincinnati score Increased from 51 ± 22 preoperatively to 90 ± 19 (P = .001). The mean Kujala scores increased from 47 ± 17 preoperatively to 82 ± 17 (P = .02), with no significant differences between patients with or without osteochondral lesions (P ≥ .05), and between male and female patients (P ≥ .08). The Insall-Salvati index was 1.1 preoperatively and remained within normal range (P = .05) at the latest follow-up.Conclusion: Combined reconstruction of MPFL and MPTL using an ipsilateral autologous gracilis tendon is satisfactory and effective and can be considered as suitable management option to treat recurrent dislocation of the patella. However, randomized studies are needed to compare different techniques.Study Design: Case series. [ABSTRACT FROM AUTHOR]

• ASE significantly improves immunofluorescence in brain primate tissue. • ASE is also effective for cell culture immunocytofluorescence. • ASE does not alter the location and/or distribution of immunolabeling. • ASE increases the intensity of immunolocalization of cancer biomarkers. • ASE is a cost-friendly alternative to clinical protocols that use commercial enhancers. The use of antibodies to identify neuronal receptors, neurotransmitters, cytoskeletal elements or pathologic protein aggregates, ion channels, adhesion molecules or other cell-type specific markers, is common practice in neuroscience. Antibody detection systems are often based on confocal, epifluorescence or brightfield microscopy. Three types of technical issues can interfere with immunolabeling: low abundance of the target protein, low specific affinity of the antibody and/or signal background sometimes related to tissue fixation. Here, giving tribute to Professor Miledi's mentorship, we propose the application of an antibody signal enhancer (ASE) solution based on glycine, hydrogen peroxide and a detergent mix as a simple, low cost, protocol variation that significantly and specifically improves the signal to noise ratio during immunostaining experiments. We describe three new settings in which ASE improves the detection of a variety of antibodies applied on long-time stored non-human primate brain sections, cell culture monolayers and on squamous carcinomas retrieved from cervical cancer patients. The significant improvement of ASE over optimized immunohistochemical protocols used in clinical practice (i.e. cancer detection) combined with its simplicity and low cost makes it an attractive method for biomedical applications. [ABSTRACT FROM AUTHOR]

Surface composition and its roughness affect the interactions that induce bone tissue growth in a biomaterial. Irregular surfaces result in better bone fixation than smoother ones, indicating that this feature might have a direct influence on osteoblast adhesion. In this paper, some surface properties of calcium aluminate cement (CAC)-based blends were evaluated, compared to commercial products as mineral trioxide aggregate (MTA) and polimetylmethacrylate (PMMA) as a reference. Roughness was measured by profilometry using samples without or with SBF (simulated body fluid) treatment for 21 days. The collagen samples, MTA and PMMA, presented higher roughness values before SBF treatment. After SBF exposure, all samples except those with PMMA showed an increase in roughness, especially the MTA ones. Cell adhesion was observed by SEM after contact with mesenchymal cell cultures. The latter adhered to the sample's surface pointing out their biocompatibility. Finally, the interactions of samples with culture medium (Dulbecco's Modified Eagle Medium = DMEM) were measured for periods of 1, 3, 7, 14, and 21 days. The sample surfaces were evaluated by SEM, EDX, FTIR and XRD. After the contact of samples with culture medium, the calcium concentration was measured by atomic absorption spectroscopy. All CAC-based blends and mainly MTA presented precipitation after treatment with DMEM, which was characterized as calcium phosphate and mainly calcium carbonate. [ABSTRACT FROM AUTHOR]

Previously, our group has established an electrochemiluminescence (ECL) molecular imaging method to detect carcinoembryonic antigen (CEA) at single tissue sections of carcinoma patients. However, the tissue fixation blocks the binding sites of surface antigens affecting the antigen-antibody interaction and the resultant visualization sensitivity. Herein, we report an antigen retrieval assisted ECL imaging strategy that utilizes heat-induced epitope retrieval (HIER) to re-expose the binding sites of the antigens for more efficient interaction between surface antigen and ruthenium-labeled antibody. With more ruthenium complexes tagged with surface antigens, the ECL intensity at the tissue sections increases significantly which could more accurately reflect the amount and the distribution of surface CEA. Accordingly, the different distribution of CEA at the carcinoma and paracancerous regions of tissue sections from two patients with lung adenocarcinoma (LUAD) is visualized, which could not be easily distinguished without the HIER treatment. Eventually, the combination of antigen retrieval and ECL molecular imaging could improve the visualization sensitivity at single tissue section and minimize the false negative phenomenon, which will greatly advance the development of ECL-based tissue imaging for future application in pathological diagnosis. [ABSTRACT FROM AUTHOR]

The logical research on fundamentally adjusted iron oxide nanoparticles has turned out to expanded in biomedicine because of the improved activity and best biocompatibility. In this present work upgraded bio-restorative and pharmacotherapeutic property of chitosan‑iron oxide nanocomposite, which was set up by eco-friendly in situ substance technique. Characterisation of the synthesised nanocomposite by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction,(XRD) and Vibrating test magnetometer (VSM) studies reveals that highly stable spherical, electron-dense core shelled rough particles of 50-60 nm. Particle morphology of the synthesised nanocomposite utilising scanning electron microscopy (SEM) uncovers spherical; thick electron centre shelled harsh particles with the size scope of 50-60 nm. FTIR studies show that the specific interaction of practical gatherings of chitosan with iron oxide nanoparticles. Crystalline phase and magnetisation impact of the composite resolved from XRD and VSM studies. Anti-bacterial activity of the nanocomposite examined against human bacterial pathogens which suggest that the readied nanocomposite successfully restrained the development of the tried bacterial strains by recording maximum zone of inhibition, least minimum inhibition concentration (MIC) and biofilm damage against the both tested strains. 100 μg dosages of nanocomposites recorded 20.0 and 21.0 mm of the zone of inhibition against E. coli and S. aureus respectively. Biofilm restraint was additionally observed to be high in nanocomposite treatment by recording lower optical density of ethanol solubilised biofilm of both tested strains. Anticancer activity was examined against the A549 cell line by the assurance of cell feasibility as opposed to oxidative proteins, articulation example of TNF-α, Bax, PARP qualities and apoptosis. Composite prompted 50% of cytotoxicity at 80 μg/mL unmistakably uncovers cytotoxicity against A549 cells. Nanocomposite treatment revealed a high decrease of cell feasibility at all the fixation and most extreme impact seen in 100 μg. Nanocomposite treated cells demonstrated striking changes in cell morphology, the build-up of atomic material related to trademark changes in against oxidative enzymes, quality articulation design which brought about apoptosis-like necrotic cell death. The present findings would propose the conceivable usage of chitosan‑iron oxide nanocomposite as a viable remedial against safe medication pathogens and malignant growth cells. Unlabelled Image • Simple eco-friendly in situ strategy achieved exceedingly stable CS-IO nanocomposite. • Synthesised CS-IONC displayed enhanced antibacterial activity against tested bacterial strains. • Inhibition of cell viability and promoted apoptosis against A 549 cell line reveals distinct anticancer activity. [ABSTRACT FROM AUTHOR]

• Tissue fixation has a major impact on antigen retrieval. • Changes in fixation or antigen retrieval protocols require re-verification and validation. • PAXgene fixation may require less stringent antigen retrieval than formalin fixation. • Antigen retrieval influences the sensitivity of immunohistochemistry. • Highest immunohistochemistry sensitivity may not correlate with medical utility. Pre-analytical factors can greatly influence the outcome of molecular analyses in medical diagnostics and research. This also applies to in situ staining techniques such as immunohistochemistry (IHC), where different types of tissue fixation methods lead to different modifications of proteins and thus can affect differently the detection by antibodies. For formalin-fixed paraffin-embedded (FFPE) tissue, antigen retrieval is applied in order to reverse the negative effects of formalin and re-establish immunoreactivity. Most antibodies and protocols used in IHC are optimized for FFPE tissue, but not for paraffin-embedded tissue treated with other fixatives such as non-crosslinking fixatives. We report results from systematic studies on distinct pre-analytical conditions in IHC, immunofluorescence and electron microscopy. Parameters investigated are the impact of crosslinking and non-crosslinking fixatives (comparing formalin and PAXgene Tissue fixation) on whole tissue, subcellular structures and organelles, as well as on ultrastructure. The results generated show that minor changes in antigen retrieval conditions may have a major impact on IHC results and that protocols optimized for crosslinking fixatives may not be used for other fixatives without re-validation. Key antigen retrieval parameters such as buffers with different pH and duration of microwave treatment must be tested systematically for each antibody and fixation protocol. [ABSTRACT FROM AUTHOR]

Abstract Surgical adhesives are an attractive alternative to traditional mechanical tissue fixation methods of sutures and staples. Ease of application, biocompatibility, enhanced functionality (drug delivery) are known advantages but weak adhesion strength in the wet environment and lack of tissue compliant behavior still pose a challenge. In order to address these issues, non-aqueous bioadhesive based on blends of polyamidoamine (PAMAM) dendrimer, conjugated with 4-[3-(trifluoromethyl)-3H-diazirin-3-yl] benzyl bromide (PAMAM-g-diazirine) and liquid polyethylene glycol (PEG 400) has been developed. PEG 400 biocompatible solvent reduces the viscosity of PAMAM-g-diazirine dendrimer without incorporating aqueous solvents or plasticizers, allowing application by syringe or spray. Upon UV activation, diazirine-generated reactive intermediates lead to intermolecular dendrimer crosslinking. The properties of the crosslinked matrix are tissue compliant, with anisotropic material properties dependent on the PEG 400 wt%, UV dose, pressure and uncured adhesive thickness. The hygroscopic PAMAM-g-diazirine/PEG 400 blend was hypothesized to absorb water at the tissue interface, leading to high interfacial adhesion, however porous matrices led to cohesive failure. The hydrophilic nature of the polyether backbone (PEG 400) shielded cationic PAMAM dendrimers with cured bioadhesive film displaying significantly less platelet activation than neat PAMAM-g-diazirine or PLGA thin films. Graphical abstract Unlabelled Image Highlights • Carbene bioadhesive blended with water-free PEG 400 accelerates gelation time. • Real-time photometry demonstrates tuneable modulus via UV dose and PEG 400 content. • Photocured bioadhesive mimics J-curve tissue moduli with flexible microporous structures. • PEG 400 improves wet adhesion strength on ex vivo soft tissues. • Shielded cationic dendrimers reduce human derived platelet adhesion and activation. [ABSTRACT FROM AUTHOR]

In this study we detail the effect of different fixation agents and the duration of storage has on the immunohistochemical staining positivity of samples of archival embryonic and fetal tissues. The samples were stained by indirect two-step immunohistochemistry (IHC) method for Ki-67, cyclin A and β-actin. Irrespective of the length of tissue archiving, tissue fixation with 10% neutral buffered formalin had better IHC intensity results in all cases when compared to methacarn-fixed tissues. In the case of β-actin, this difference was statistically significant, while differences in Ki-67 and cyclin A were not. The second aspect studied was which effect tissue block archiving duration has on the IHC reactivity. We demonstrated a statistically significant decrease in IHC positivity for all studied antigens between the samples that were archived for 10–19 or 20–45 years, regardless the fixative solution. To the best of our knowledge, the influence that the duration of tissue block archiving has on IHC positivity in human embryo and fetal tissue material has not yet been studied. Although the causes of the IHC positivity decline in archived tissue blocks are not well understood, a possible decrease in IHC over time should be considered, particularly in retrospective studies. [ABSTRACT FROM AUTHOR]

Abstract In investigation of (patho)physiological processes, cells represent frequently used analyte as an exceptional source of information. However, spectroscopic analysis of live cells is still very seldom in clinics, as well as in research studies. Among others, the reasons are long acquisition time during which autolysis process is activated, necessity of specified technical equipment, and inability to perform analysis in a moment of sample preparation. Hence, an optimal method of preserving cells in the existing state is of extreme importance, having in mind that selection of fixative is cell lineage dependent. In this study, two commonly used chemical fixatives, formaldehyde and methanol, are used for preserving primary mesenchymal stem cells extracted from periodontal ligament, which are valuable cell source for reconstructive dentistry. By means of Raman spectroscopy, cell samples were probed and the impact of these fixatives on their Raman response was analyzed and compared. Different chemical mechanisms are the core processes of formaldehyde and methanol fixation and certain Raman bands are shifted and/or of changed intensity when Raman spectra of cells fixed in that manner are compared. In order to get clearer picture, comprehensive statistical analysis was performed. Graphical Abstract Unlabelled Image Highlights • Raman spectroscopy was used in order to define the influence of chemical fixatives on primary mesenchymal stem cells' Raman spectra. • Methanol and formaldehyde were used as fixative agents. • The data was statistically treated by Principal Component Analysis to validate the results. [ABSTRACT FROM AUTHOR]

Abstract Mitochondria are considered as a therapeutic target for new drug design toward all kinds of cancer. Hence in order to enhance the dosage in mitochondrial fraction of cinnamamides, the mitochondria-targeted derivatives were designed by the incorporation of cinnamamides into a fluorophore carrier of coumarin-3-carboxamide with a 1:1 stoichiometry. Using the amide linkers, twenty-one compounds were synthesized and the cytotoxicity against a panel of cancer cells (MCF-7, Hela, HepG2, HL-60) was tested. In particular, compound 18c displayed the potent cytotoxicity toward HL-60 leukaemia cells, which could quickly and efficiently entry into HL-60 cells and specifically localize within mitochondria. And 18c preferred enrichment in HL-60 cells than in PBMC normal cells, accounting for the higher toxicity to cancer cells than to normal cells. Moreover, the dissipations of mitochondrial membrane potential and enhancement of cellular ROS level were also preceded upon 18c treatment, leading to cell cycle arrest and apoptosis/necrosis in HL-60 cells. Besides, acted as a Michael acceptor, 18c initiated a thia-Michael addition reaction toward cysteamine (1:2 stoichiometry), detecting by the UV-Vis spectrum and HRMS analysis. This could result in the blue emission of 18c in mitochondria after the procedure of cell fixation, owing to the formation of covalent bond with mitochondrial thiols. Our study reported 18c might be useful for the further development into a mitochondria-targeted anti-leukemia agent and the Michael acceptor might be a versatile functional group. Graphical abstract Image 1 Highlights • Cinnamamide derivatives were devised to target mitochondria and emit fluorescence. • 18c exhibited the potent cytotoxicity and selectivity to HL-60 cells. • The uptake level of 18c in HL-60 cells was higher than in PBMC normal cells. • The accumulation and retention performance in mitochondria of 18c were observed. • 18c induced mitochondria dysfunction and cell cycle arrest. [ABSTRACT FROM AUTHOR]

Abstract Objectives This study aimed to develop a simple and efficient numerical modeling approach for characterizing strain and total strain energy in bone scaffolds implanted in patient-specific anatomical sites. Materials and methods A simplified homogenization technique was developed to substitute a detailed scaffold model with the same size and equivalent orthotropic material properties. The effectiveness of the proposed modeling approach was compared with two other common homogenization methods based on periodic boundary conditions and the Hills-energy theorem. Moreover, experimental digital image correlation (DIC) measurements of full-field surface strain were conducted to validate the numerical results. Results The newly proposed simplified homogenization approach allowed for fairly accurate prediction of strain and total strain energy in tissue scaffolds implanted in a large femur mid-shaft bone defect subjected to a simulated in-vivo loading condition. The maximum discrepancy between the total strain energy obtained from the simplified homogenization approach and the one obtained from detailed porous scaffolds was 8.8%. Moreover, the proposed modeling technique could significantly reduce the computational cost (by about 300 times) required for simulating an in-vivo bone scaffolding scenario as the required degrees of freedom (DoF) was reduced from about 26 million for a detailed porous scaffold to only 90,000 for the homogenized solid counterpart in the analysis. Conclusions The simplified homogenization approach has been validated by correlation with the experimental DIC measurements. It is fairly efficient and comparable with some other common homogenization techniques in terms of accuracy. The proposed method is implicating to different clinical applications, such as the optimal selection of patient-specific fixation plates and screw system. Graphical abstract fx1 Highlights • The proposed simplified homogenization approach could predict the total strain energy accurately. • Computational cost was decreased substantially  by using the proposed homogenization approach. • Validation of homogenization results with digital image correlation (DIC) measurements for bone tissue scaffolding. • Numerical results were in good agreement with those of the experimental results. [ABSTRACT FROM AUTHOR]

Abstract Background Anti-HER2 therapy has not demonstrated a survival advantage in the second-line setting of patients with HER2-positive gastric cancer. We conducted this study to assess changes in HER2 status and to identify possible biomarkers for acquired resistance after the use of trastuzumab as the first-line therapy. Patients and methods Patients with advanced or recurrent HER2-positive gastric adenocarcinoma who were diagnosed with progressive disease after the first-line trastuzumab-based therapy and developed pathologically confirmed adenocarcinoma within 3 months after completion of trastuzumab-based therapy were enrolled in this study. We collected re-biopsied samples from the HER2-positive patients who had developed resistance to trastuzumab and re-evaluated their HER2 status. Amplification of EGFR and c-met , as well as PIK3CA mutation, were comparatively analysed when samples were available. Results Among 33 eligible patients, loss of HER2 was identified in 20 patients (60.6%) with refractory disease. Immunohistochemistry showed that the rate of HER2 overexpression was greatly reduced after therapy (pre-HER2 3+: 24 [72.7%] vs. post-HER2 3+: 13 [39.4%]). We found that the use of fixatives other than 10% neutral buffered formalin significantly reduced the HER2-positive rate. EGFR amplification, c-met amplification and PIK3CA mutation before and after trastuzumab-based therapy were observed in 10.3% and 3.8%, 17.9% and 4.2% and 4.0% and 4.2% of cases, respectively. Conclusion Re-evaluation of HER2 status is needed to determine the appropriate use of anti-HER2–targeted therapy after disease progression. Our results also highlight the importance of formalin fixation conditions for HER2 testing. Highlights • The HER2 status was re-evaluated using re-biopsied samples from the patients with HER2-positive gastric cancer. • Among 33 eligible patients, the loss of HER2 was identified in 20 patients (60.6%) with refractory disease. • The use of fixatives, other than 10% neutral buffered formalin, reduced the HER2-positive rate. [ABSTRACT FROM AUTHOR]

This Special Issue describes the impact of visual impairment on visuomotor function. It includes contributions that examine gaze control in conditions associated with abnormal visual development such as amblyopia, dyslexia and neurofibromatosis as well as disorders associated with field loss later in life, such as macular degeneration and stroke. Specifically, the papers address both gaze holding (fixation), and gaze-following behavior (single saccades, sequences of saccades and smooth-pursuit) that characterize active vision in daily life and evaluate the influence of both pathological and simulated field loss. Several papers address the challenges to reading and visual search; describing how the patterns of eye movements in these real-world tasks adapt to visual impairment and highlighting how they could serve as diagnostic markers of visuomotor function. [ABSTRACT FROM AUTHOR]

An economic evaluation was performed alongside an RCT investigating flap fixation in reducing seroma formation after mastectomy. The evaluation focused on the first year following mastectomy and assessed cost-effectiveness from a health care and societal perspective. The economic evaluation was conducted between 2014 and 2018 in four Dutch breast clinics. Patients with an indication for mastectomy or modified radical mastectomy were randomly assigned to: conventional closure (CON), flap fixation with sutures (FFS) or flap fixation with tissue glue (FFG). Health care costs, patient and family costs and costs due to productivity losses were assessed. Outcomes were expressed in incremental cost-effectiveness ratios (ICERs): the incremental cost per quality-adjusted life year (QALY). Bootstrapping techniques, sensitivity and secondary analyses were employed to address uncertainty. The FFS-group yielded most QALYs (0.810; 95%-CI 0.755–0.856), but also incurred the highest mean costs at twelve months (€10.416; 95%-CI 8.231–12.930). CON was the next best alternative with 0.794 QALYs (95%-CI 0.733–0.841) and mean annual costs of €10.051 (95%-CI 8.255–12.044). FFG incurred fewer QALYs and higher costs, when compared to the CON group. The ICER of FFS compared to CON was €22.813/QALY. Applying a willingness to pay threshold in the Netherlands of €20.000/QALY, the probability that FFS was cost-effective was 42%, compared to 37% and 21% for CON and FFG, respectively. The cost-effectiveness of FFS following mastectomy, versus CON and FFG, is uncertain from a societal perspective. Yet, from a health care and hospital perspective FFS is likely to be the most cost-effective intervention. [ABSTRACT FROM AUTHOR]

• Open tibia fracture (OTF) causes a considerable increase in morbidity and risk for complications compared to closed fractures. • The incidence of reoperation due to nonunion decreased from 27.7% to 9.7% after implementing BOAST 4 based OTF treatment protocol. • A structured OTF treatment protocol reduced the incidence of fracture related infection from 20.6% to 1.6% in a tertiary trauma unit. • Definitive fixation and soft tissue coverage performed in separate operations increased the risk for both FRI and reoperation due to nonunion. Open tibia fracture (OTF) causes a considerable increase in morbidity and risk for complications compared to closed fractures. The most significant OTF complication leading to morbidity is commonly considered to be fracture-related infection (FRI). In September 2016, Tampere University Hospital (TAUH) introduced a treatment protocol for OTFs based on the BOAST 4 guideline. The aim of this study is to investigate the outcomes before and after implementation of the OTF treatment protocol. A retrospective cohort study was conducted using handpicked data from the patient record databases of TAUH from May 1, 2007, to May 10, 2021. For patients with OTF, we collected descriptive information, known risk factors for FRI and nonunion, bony fixation method, possible soft tissue reconstruction method, information about the timing of internal fixation and soft tissue coverage, and timing of primary operation. As outcome measures, we collected information on FRI, reoperation due to non-union, flap failure, and secondary amputation. We then compared the incidence of complications before and after the implementation of the OTF treatment protocol at TAUH. After predefined exclusions, a total of 203 patients with OTF were included. Of these, 141 were treated before and 62 after the implementation of the OTF treatment protocol. The FRI rate in the pre-protocol group was significantly higher compared to the protocol group (20.6% vs 1.6%, p = 0.0015). The incidence of reoperation due to nonunion was also significantly higher in the pre-protocol group (27.7% vs 9.7%, p = 0.0054). According to multivariable analysis, definitive fixation and soft tissue coverage performed in separate operations was an independent risk factor for both FRI and reoperation due to nonunion. After implementation, the BOAST 4 based OTF treatment protocol reduced the rate of FRI and reoperation due to nonunion in patients with OTF treated at TAUH during the study period. We, therefore, recommend the implementation of such a treatment protocol in all major trauma centers treating patients with OTF. Furthermore, we also recommend the immediate referral of patients with complex OTF from hospitals lacking the preconditions to provide BOAST 4 based treatment to specialized centers. [ABSTRACT FROM AUTHOR]

Background: The posterolateral and medial aspect of the arm is supplied by the axillary (AXN) and intercostobrachial nerves (ICBN), which are not anaesthetised by an axillary brachial plexus block (ABPB). Blockade of the AXN and the ICBN has been reported in the quadrangular space (QS) posteriorly or by serratus plane block, respectively. An anterior ultrasound-guided approach to block the AXN and ICBN would be desirable to complete an ABPB at a single insertion site.Methods: After a preliminary dissection study in six cadavers, ultrasound-guided AXN and ICBN injection was performed in 46 Thiel embalmed cadavers bilaterally. Key sonographic landmarks to identify the AXN in the QS are the humerus, teres major muscle, and subscapular muscle. With the same probe position, the ICBN was identified in the subfascial axillary space. Then, 2 ml latex was injected at each nerve and confirmed by dissection.Results: Muscular and bony landmarks were identified in all cadavers. The AXN was seen in 99% in the QS or at the inferolateral margin of the subscapular muscle and surrounded by latex in 96% of cases. Latex spread to the axillary fossa, within the subscapular muscle, or to the radial nerve was noted in 8% of the injections. The ICBN was seen and surrounded by latex in 100% of cases.Conclusions: We describe a reliable ultrasonographic approach to visualise the AXN and ICBN anteriorly from the conventional ABPB approach as confirmed in this cadaver study. [ABSTRACT FROM AUTHOR]

More than a century ago in 1893, a revolutionary idea about fixing biological tissue specimens was introduced by Ferdinand Blum, a German physician. Since then, a plethora of fixation methods have been investigated and used. Formalin fixation with paraffin embedment became the most widely used types of fixation and preservation method, due to its proper architectural conservation of tissue structures and cellular shape. The huge collection of formalin-fixed, paraffin-embedded (FFPE) sample archives worldwide holds a large amount of unearthed information about diseases that could be the Holy Grail in contemporary biomarker research utilizing analytical omics based molecular diagnostics. The aim of this review is to critically evaluate the omics options for FFPE tissue sample analysis in the molecular diagnostics field. [ABSTRACT FROM AUTHOR]

The selection of an ideal screw size plays a crucial role in the success of spinal instrumentation as larger diameter screws are thought to provide better fixation strength but increase the risk of pedicle failure during insertion. On the other hand, smaller diameter screws are with lesser risk of pedicle breakage but are thought to compromise the stability of the instrumentation. By investigating the relationship between screw diameter and the pullout strength of pedicle screws after fatigue loading, this study seeks to find quantitative biomechanical data for surgeons in determining the most ideal diameter size screws when performing surgical implementations on osteoporotic vertebrae. Twenty-seven osteoporotic (BMD ranged: 0.353–0.848 g/cm 2 ) thoracic vertebrae (T3-T8) were harvested from 5 human cadavers. Two sizes of poly-axial screws (5.0 mm × 35 and 4.35 mm × 35) were implanted into each pedicles of the vertebrae by an experienced surgeon. Specimens were randomly distributed into control group, fatigue group of 5000 and 10,000 cycles with peak-to-peak loadings of 10–100 N at 1 Hz. Each specimen was then axial pullout tested at a constant rate of 5 mm/min. The ultimate pullout strength (N) & stiffness (N/mm) were obtained for analysis. The results showed that although the larger diameter screws achieved superior pullout strength immediately after the implantation, both sizes of screws exhibited comparable pullout strengths post fatigue loading. This indicates that the smaller diameter screws may be considered for surgical techniques performed on osteoporotic vertebrae for reduced risk of pedicle breakage without sacrificing fixation strength. [ABSTRACT FROM AUTHOR]

Trauma to the pelvis is debilitating and often needs fixation intervention. In 58% of patients with this trauma, the injuries can lead to permanent disability, preventing the return to jobs. Of all unsuccessful fixation procedures, 42% are caused by failures of the method, sometimes due to mobilization during healing. Patients would benefit by havibridgetv@comcast.netng fixation hardware in place that enabled ambulation. During walking the bilateral hip joint plus leg and trunk muscle forces, including those from hip motion, can induce torsion into the pelvic ring and across the joint cartilages, and affect the internal stresses of the pelvis. For an accurate understanding, fixation that bridges the bilateral innominate bones needs to be evaluated considering all of these factors, and the affect on the stresses throughout the pelvic ring. Yet there is no bilateral, comprehensive method to do so in the literature. In this study a method was developed that incorporates all of the necessary factors in four bilateral, static, finite element models representing eight gait phases. The resulting stress migration through the full pelvic ring and pubic symphysis displacements were demonstrated under these conditions. In subsequent work, fixation improvements can be applied to these models to evaluate the change in internal stresses, joint displacements and deformations of the hardware, leading to a better quality of design and permitting ambulation during healing for the patient. [ABSTRACT FROM AUTHOR]

An alcohol-based non-crosslinking tissue fixative, PAXgene Tissue System, has been proposed as alternative fixation method to formalin, providing superior and morphological preservation. To date, metabolites have not been assessed in PAXgene-fixed tissues. The study focuses on a comparison between PAXgene and standard formalin fixation for metabolomic analysis by MALDI mass spectrometry imaging. Therefore, fifty-six samples from seven mice organs were fixed with PAXgene (PFPE) or formalin (FFPE), embedded in paraffin, and processed to a tissue microarray. PAXgene was able to spatially preserve metabolites in organs achieving an overlap of common metabolites ranging from 34 to 78% with FFPE. Highly similar signal intensities and visualization of molecules demonstrated negligible differences for metabolite imaging on PFPE compared to FFPE tissues. In addition, we performed proteomic analysis of intact proteins and peptides derived from enzymatic digestion. An overlap of 33 to 58% was found between FFPE and PFPE tissue samples in peptide analysis with a higher number of PFPE-specific peaks. Analysis of intact proteins achieved an overlap in the range of 0 to 28% owing to the poor detectability of cross-linked proteins in formalin-fixed tissues. Furthermore, metabolite and peptide profiles obtained from PFPE tissues were able to correctly classify organs independent of the fixation method, whereas a distinction of organs by protein profiles was only achieved by PAXgene fixation. Finally, we applied MALDI MSI to human biopsies by sequentially analyzing metabolites and peptides within the same tissue section. Concerning prospective studies, PAXgene can be used as an alternative fixative for multi-omic tissue analysis. [ABSTRACT FROM AUTHOR]

Host responses to a biomaterial critically influence its in vivo performance. Biomaterial architectures that can recruit endogenous host stem cells could be beneficial in tissue regeneration or integration. Here, we report that the fibrous topography of biomaterials promotes the recruitment of host mesenchymal stem cells (MSCs) by facilitating the macrophage phenotype transition from M1-to-M2. Electrospun poly (ε-caprolactone) fiber (PCL-fiber) films were implanted into the subcutaneous tissues of rats, and the response of host cells to the PCL-fiber was evaluated and compared with those of solid ones (PCL-solid). During the initial post-implantation period, greater numbers of cells were recruited and adhered to the PCL-fiber compared to the PCL-solid, and the cells exhibited the M1 phenotype, which was supported by the enhanced adsorption of complement C3a to the implanted PCL-fiber. Subsequently, the PCL-fiber supported the macrophage phenotype transition from M1-to-M2, which was confirmed by the ratio of M2/M1 marker (CD163/CCR7)-positive cells and by the expression of M2/M1 markers (arginase-1/iNOS). The PCL-fiber also reduced the formation of foreign body giant cells. MSC marker (CD29, CD44, and CD90)-positive cells began to appear as early as day 4 on the PCL-fiber, while few MSCs were observed on the PCL-solid. The MSCs migration ex vivo assay showed that MSCs substantially migrated across the trans -wells toward the implanted PCL-fiber. The cells on the implanted PCL-fiber expressed and secreted substantial levels of SDF-1 (CXCL-12), while anti-SDF-1 neutralizing antibody abrogated the MSCs migration. Taken together, these results provide evidence that the fibrous topography of biomaterials enhances the recruitment of MSCs by promoting macrophage recruitment, facilitating M1-to-M2 transition, and enhancing SDF-1 secretion. [ABSTRACT FROM AUTHOR]

Cellular behaviors, such as differentiation, are regulated by complex ligation processes involving cell surface receptors, which can be activated by various divalent metal cations. The design of nanoparticle for co-delivery of ligand and ligation activator can offer a novel strategy to synergistically stimulate ligation processes in vivo . Here, we present a novel layered double hydroxide (LDH)-based nanohybrid (MgFe-Ado-LDH), composed of layered MgFe hydroxide nanocarriers sandwiching the adenosine cargo molecule, maintained through an electrostatic balance, to co-deliver the adenosine (Ado) ligand from the interlayer spacing and the Mg 2+ ion (ligation activator) through the dissolution of the MgFe nanocarrier itself. Our findings demonstrate that the MgFe-Ado-LDH nanohybrid promoted osteogenic differentiation of stem cells through the synergistic activation of adenosine A2b receptor (A2bR) by the dual delivery of adenosine and Mg 2+ ions, outperforming direct supplementation of adenosine alone. Furthermore, the injection of the MgFe-Ado-LDH nanohybrid and stem cells embedded within hydrogels promoted the healing of rat tibial bone defects through the rapid formation of fully integrated neo-bone tissue through the activation of A2bR. The newly formed bone tissue displayed the key features of native bone, including calcification, mature tissue morphology, and vascularization. This study demonstrates a novel and effective strategy of bifunctional nanocarrier-mediated delivery of ligand (cargo molecule) and activation of its ligation to receptor by the nanocarrier itself for synergistically inducing stem cell differentiation and tissue healing in vivo , thus offering novel design of biomaterials for regenerative medicine. [ABSTRACT FROM AUTHOR]

Microglia are known as the most motile cells in the central nervous system (CNS). It was shown in vivo that they permanently scan their direct microenvironment and react to pathological conditions within minutes. Many studies of brain pathologies use fixed brain tissue to investigate cellular changes. Unfortunately, due to technical reasons, the time span between the induction of the fixation procedure (start of the perfusion) and the finally-fixed tissue lasts several minutes, giving time to microglia to start reacting to the ischemic conditions due to perfusion start. Here, we investigated the microglial changes generated by the fixation itself in TgH(CX3CR1-EGFP) mice with fluorescent labelled microglia using confocal laser scanning microscopy (CLSM) of fixed brain tissue as well as two-photon laser scanning microscopy (2P-LSM) during the perfusion of a living animal. We revealed the impact of fixation and buffer parameters on cell morphology. The largest morphological differences compared to physiological in vivo branch arborization were observed when the directly dissected brain was immersed in paraformaldehyde fixation solution overnight, without prior fixative perfusion of the animal. But even perfusion with a fixative, followed by post-fixation leads to small changes in microglial process length and number and could not be prevented when compared to physiological in vivo microglia morphology acquired using in vivo 2P-LSM. Interestingly, perfusion with different buffers either oxygenated artificial cerebrospinal fluid or phosphate buffered saline prior to perfusion-fixation showed minor microglia changes in arborization and/or number of processes. Fixation methods influence microglia morphology. Therefore, to define microglia activation states immunohistochemical stainings or genetic labelling of the cells have to be included in addition to morphological analysis. [ABSTRACT FROM AUTHOR]

Organismal fitness depends on adaptation to complex niches where chemical compounds and pathogens are omnipresent. These stresses can lead to the fixation of alleles in both xenobiotic responses and proliferative signaling pathways that promote survival in these niches. However, both xenobiotic responses and proliferative pathways vary within and among species. For example, genetic differences can accumulate within populations because xenobiotic exposures are not constant and selection is variable. Additionally, neutral genetic variation can accumulate in conserved proliferative pathway genes because these systems are robust to genetic perturbations given their essential roles in normal cell-fate specification. For these reasons, sensitizing mutations or chemical perturbations can disrupt pathways and reveal cryptic variation. With this fundamental view of how organisms respond to cytotoxic compounds and cryptic variation in conserved signaling pathways, it is not surprising that human patients have highly variable responses to chemotherapeutic compounds. These different responses result in the low FDA-approval rates for chemotherapeutics and underscore the need for new approaches to understand these diseases and therapeutic interventions. Model organisms, especially the classic invertebrate systems of Caenorhabditis elegans and Drosophila melanogaster , can be used to combine studies of natural variation across populations with responses to both xenobiotic compounds and chemotherapeutics targeted to conserved proliferative signaling pathways. [ABSTRACT FROM AUTHOR]

Background CAD/CAM reconstruction plates have become a viable option for mandible reconstruction. The aim of this study was to determine whether CAD/CAM plates provide higher fatigue strength compared with conventional fixation systems. Material and methods 1.0 mm miniplates, 2.0 mm conventional locking plates (DePuy Synthes, Umkirch, Germany), and 2.0 mm CAD/CAM plates (Materialise, Leuven, Belgium/DePuy Synthes) were used to reconstruct a polyurethane mandible model (Synbone, Malans, CH) with cortical and cancellous bone equivalents. Mastication was simulated via cyclic dynamic testing using a universal testing machine (MTS, Bionix, Eden Prairie, MN, USA) until material failure reached a rate of 1 Hz with increasing loads on the left side. Results No significant difference was found between the groups until a load of 300 N. At higher loads, vertical displacement differed increasingly, with a poorer performance of miniplates ( p = 0.04). Plate breakage occurred in miniplates and conventional locking plates. Screw breakage was recorded as the primary failure mechanism in CAD/CAM plates. Stiffness was significantly higher with the CAD/CAM plates ( p = 0.04). Conclusion CAD/CAM plates and reconstruction plates provide higher fatigue strength than miniplates, and stiffness is highest in CAD/CAM systems. All tested fixation methods seem sufficiently stable for mandible reconstruction. [ABSTRACT FROM AUTHOR]

Reports of preserved cells and other soft tissues in ancient vertebrates, including dinosaurs, have been met with controversy within the field of vertebrate palaeontology. To explain such reports, Schweitzer et al. (2014) hypothesized that iron-mediated radical crosslinking preserves ancient soft tissues in a manner somewhat analogous to histological tissue fixation. In 2018, Wiemann et al. proposed a second hypothesis that these soft tissues were preserved as advanced glycation/lipoxidation end products (AGEs/ALEs). The chemistry underlying these hypotheses, however, remains poorly described for fossil vertebrates. This review posits a chemical framework describing the persistence of biological "soft" tissues into deep time. The prior iron-mediated radical crosslinking and AGE/ALE mechanisms are re-described in context of established chemistry from a diversity of scientific fields. Significantly, this framework demonstrates the hypotheses presented by Schweitzer et al. (2014) and Wiemann et al. (2018) are, in many cases, subsequent steps of a single, unified reaction mechanism, and not separate hypotheses. Knowledge of the chemical mechanisms underlying vertebrate soft tissue preservation has direct implications for molecular archaeology and palaeontology, including efforts at molecular sequence recovery within the ancient DNA and palaeoproteomic communities. Such implications that are immediately apparent from examining the chemical framework are discussed. [ABSTRACT FROM AUTHOR]

Mg–Ca–Zn alloy has been suggested for the application of fixation materials during maxillofacial surgery. We investigated the stability of Mg–Ca–Zn alloy for clinical application during orthognathic surgery. The finite element model for the fixation of sagittal split ramus osteotomy was constructed. In the bicortical screw fixation of the mandible setback condition, the stress distributions of Mg–Ca–Za alloy, polylactic acid polymer, and titanium were evaluated using the virtual model with occlusal loading of 132 N. The deformations of the three different materials of fixation screw were observed according to masticatory force ranging from 132 to 1,000 N. When comparing the stress distribution placed on cortical bone between the polymer and magnesium alloy groups, the magnesium alloy screws could bear more stress, thereby decreasing the stress, which might be distributed to other biologic components, such as the condyle and cortical ramus of the mandible. Deformations of the screws according to functional load were minimal, and the deformation remained <0.21 mm at the initial functional load of the mandible after surgery, regardless of materials used. The biodegradable magnesium alloy screw can bear more stress and decrease the detrimental effect on the stability of sagittal split ramus osteotomy setback surgery. [ABSTRACT FROM AUTHOR]

Approximately 20% early-stage (I/II) colorectal cancer (CRC) patients develop metastases despite curative surgery. We aim to develop a formalin-fixed and paraffin-embedded (FFPE)-based predictor of metastases in early-stage, clinically-defined low risk, microsatellite-stable (MSS) CRC patients. We considered genome-wide mRNA and miRNA expression and mutation status of 20 genes assayed in 150 fresh-frozen tumours with known metastasis status. We selected 193 genes for further analysis using NanoString nCounter arrays on corresponding FFPE tumours. Neither mutation status nor miRNA expression improved the estimated prediction. The final predictor, ColoMet19, based on the top 19 genes' mRNA levels trained by Random Forest machine-learning strategy, had an estimated positive-predictive-value (PPV) of 0.66. We tested ColoMet19 on an independent test-set of 131 tumours and obtained a population-adjusted PPV of 0.67 indicating that early-stage CRC patients who tested positive have a 67% risk of developing metastases, substantially higher than the metastasis risk of 40% for node-positive (Stage III) patients who are generally treated with chemotherapy. Predicted-positive patients also had poorer metastasis-free survival (hazard ratios [HR] = 1.92, design-set; HR = 2.05, test-set). Thus, early-stage CRC patients who test positive may be considered for adjuvant therapy after surgery. [ABSTRACT FROM AUTHOR]

Aim: To investigate image interpretation performance by diagnostic radiography students, diagnostic radiographers and reporting radiographers by computing eye gaze metrics using eye tracking technology.Methods: Three groups of participants were studied during their interpretation of 8 digital radiographic images including the axial and appendicular skeleton, and chest (prevalence of normal images was 12.5%). A total of 464 image interpretations were collected. Participants consisted of 21 radiography students, 19 qualified radiographers and 18 qualified reporting radiographers who were further qualified to report on the musculoskeletal (MSK) system.Outcome Measures: Eye tracking data was collected using the Tobii X60 eye tracker and subsequently eye gaze metrics were computed. Voice recordings, confidence levels and diagnoses provided a clear demonstration of the image interpretation and the cognitive processes undertaken by each participant. A questionnaire afforded the participants an opportunity to offer information on their experience in image interpretation and their opinion on the eye tracking technology.Results: Reporting radiographers demonstrated a 15% greater accuracy rate (p≤0.001), were more confident (p≤0.001) and took a mean of 2.4s longer to clinically decide on all features compared to students. Reporting radiographers also had a 15% greater accuracy rate (p≤0.001), were more confident (p≤0.001) and took longer to clinically decide on an image diagnosis (p=0.02) than radiographers. Reporting radiographers had a greater mean fixation duration (p=0.01), mean fixation count (p=0.04) and mean visit count (p=0.04) within the areas of pathology compared to students. Eye tracking patterns, presented within heat maps, were a good reflection of group expertise and search strategies. Eye gaze metrics such as time to first fixate, fixation count, fixation duration and visit count within the areas of pathology were indicative of the radiographer's competency.Conclusion: The accuracy and confidence of each group could be reflected in the variability of their eye tracking heat maps. Participants' thoughts and decisions were quantified using the eye tracking data. Eye tracking metrics also reflected the different search strategies that each group of participants adopted during their image interpretations. This is the first study to use eye tracking technology to assess image interpretation skills between various groups of different levels of experience in radiography, especially on a combination of the MSK system, chest cavity and a variety of pathologies. [ABSTRACT FROM AUTHOR]

Hallux valgus (HV) was one of the most frequent female foot deformities. The aim of this study was to evaluate mechanical responses and stabilities of the Kirschner, bandage and fiberglass fixations after the distal metatarsal osteotomy in HV treatment. Surface traction of different forefoot regions in bandage fixation and the biomechanical behavior of fiberglass bandage material were measured by a pressure sensor device and a mechanical testing, respectively. A three-dimensional foot finite element (FE) model was developed to simulate the three fixation methods (Kirschner, bandage and fiberglass fixations) in weight bearing. The model included 28 bones, sesamoids, ligaments, plantar fascia, cartilages and soft tissue. The peak Von Mises stress (MS) and compression stress (CS) of the distal fragment were predicted from the three fixation methods: Kirschner fixation (MS = 6.71 MPa, CS = 1.232 MPa); Bandage fixation (MS = 14.90 MPa, CS = 9.642 MPa); Fiberglass fixation (MS = 15.83 MPa, CS = 19.70 MPa). Compared with the Kirschner and bandage fixation, the fiberglass fixation reduced the relative movement of osteotomy fragments and obtained the maximum CS. We concluded that fiberglass fixation in HV treatment was helpful to the bone healing of distal fragment. The findings were expected to guide further therapeutic planning of HV patient. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate the possibility of implanting the anterior atlantoaxial lateral mass intervertebral cage, a new type of fixation, by the transoral approach.Method: This study examined the possibility of implantation in vivo by the quantitative measurement on the dry atlantoaxial bone and implantation of the anterior atlantoaxial lateral mass intervertebral cage in specimens. Anterior atlantoaxial lateral mass intervertebral cages were implanted in 10 atlantoaxial joint specimens using the transoral approach. Eight anatomical parameters (width, the thickness, ordinates, abscissas, and declination angles of the mass) from each of the 30 dry atlas and axis bone specimens were measured. These parameters determined the size and the design of the cage and the way of implantation.Results: The course of the vertebral artery forms the safe boundary for transoral surgery. The shape of the area of work exposure was an inverted trapezoid. In specimens, the anterior atlantoaxial lateral mass intervertebral cages could be successfully implanted using the transoral approach. The parameters of the human atlantoaxial lateral masses exposed anteriorly showed that there was enough space, for the safe anterior implantation of the cage. The surgery using the transoral atlantoaxial reduction and plate makes possible the implantation of the anterior cage.Conclusion: The implantation of anterior atlantoaxial lateral mass intervertebral cage through transoral approach is possible. [ABSTRACT FROM AUTHOR]

This study assessed whether specific eye movement patterns are observed during emotional autobiographical retrieval. Participants were asked to retrieve positive, negative and neutral memories while their scan path was recorded by an eye-tracker. Results showed that positive and negative emotional memories triggered more fixations and saccades but shorter fixation duration than neutral memories. No significant differences were observed between emotional and neutral memories for duration and amplitude of saccades. Positive and negative retrieval triggered similar eye movement (i.e., similar number of fixations and saccades, fixation duration, duration of saccades, and amplitude of saccades). Interestingly, the participants reported higher visual imagery for emotional memories than for neutral memories. The findings demonstrate similarities and differences in eye movement during retrieval of neutral and emotional memories. Eye movement during autobiographical retrieval seems to be triggered by the creation of visual mental images as the latter are indexed by autobiographical reconstruction. [ABSTRACT FROM AUTHOR]

Prior findings suggest that coping with distraction relies on cognitive control processes that increase attention to task-relevant processing and/or decrease attention to task-irrelevant processing. In line with this view, the size of the congruency effect in unimodal Stroop-like tasks, a popular measure of distraction, is typically reduced after more distracting incongruent trials relative to after less distracting congruent trials. It remains unclear, however, whether, and under what conditions, the control processes underlying this congruency sequence effect (CSE) minimize cross-modal distraction. The contingent attentional capture hypothesis predicts a cross-modal CSE when a distracter possesses a target-defining feature. In contrast, the perceptual conflict hypothesis predicts a cross-modal CSE when there is perceptual conflict between a distracter and a target. To distinguish between these hypotheses, we conducted two experiments wherein an auditory distracter word preceded a visual target that appeared in one of two formats (i.e., word or arrow). We observed robust, cross-modal CSEs. Moreover, the pattern of CSEs that we observed was more consistent with the contingent attentional capture hypothesis than with the perceptual conflict hypothesis. These findings reveal a novel attentional mechanism for minimizing cross-modal distraction. [ABSTRACT FROM AUTHOR]

Epidural catheter migration is a well-known cause of failed anesthesia and complications. One of the factors that affect catheter movement is when patients change their position after skin fixation. We report a case of an epidural catheter placed without evidence of intravascular or subdural insertion that produced an insufficient block. A 36-year-old woman presented for ankle surgery under epidural anesthesia. Epidural block was conducted at the L3-4 intervertebral space with a catheter threaded 3 cm into the epidural space with the patient in a back flexion and lateral position. The total volume of injected anesthetic was 28 mL, including a 3-mL test dose. The final anesthesia level was L1. The planned operation was completed without a pneumatic tourniquet. A postoperative C-arm fluoroscopic image revealed that 1 side hole of the catheter had moved out of the epidural space. We think that a positional change after catheter fixation was the reason for catheter outmigration leading to insufficient analgesia, which was incompatible with the amount of local anesthetic injected. [ABSTRACT FROM AUTHOR]

Objective Osteoporosis is a risk factor for implant fixation failure. The inhibition of sclerostin effectively improves bone formation and bone remodeling. Therefore, this study investigated whether SOST deficiency enhances the osseointegration of implants in a mouse model of osteoporosis induced by ovariectomy (OVX). Design Osteoporosis was induced in female C57BL/6 and SOST deficient mice by OVX. Titanium implants were placed in the bilateral distal aspects of the femurs. Implants underwent sandblasting and acid-etching after which the structure, surface roughness and chemical components were investigated using scanning electron microscopy (SEM) and energy spectrum analyses. Undecalcified slices, μ-CT, histology analyses and mechanical tests were used to evaluate the osseointegration of implants. The results were compared using one-way ANOVA between four groups. Results Sandblasting and acid-etching increased the roughness of the implants. OVX surgery reduced bone formation around the implants in both WT and SOST −/− mice. However, implant osseointegration was significantly improved in the SOST −/− OVX mice compared to the WT OVX mice. Conclusions Inhibition of the SOST gene improved implant fixation in the OVX osteoporotic mice, which suggests a strategy for enhancing implant osseointegration in clinical patients with osteoporosis. [ABSTRACT FROM AUTHOR]

Surgical correction of premature fusion of calvarial sutures involving the fronto-orbital region can be challenging due to the demanding three-dimensional (3D) anatomy. If fronto-orbital advancement (FOA) is necessary, surgery is typically performed using resorbable plates and screws that are bent manually intraoperatively. A new approach using individually manufactured resorbable implants (KLS Martin Group, Tuttlingen, Germany) is presented in the current paper. Preoperative CT scan data were processed in iPlan (ver. 3.0.5; Brainlab, Feldkirchen, Germany) to generate a 3D reconstruction. Virtual osteotomies and simulation of the ideal outer contour with reassembled bony segments were performed. Digital planning was transferred with a cutting guide, and an individually manufactured resorbable implant was used for rigid fixation. A resorbable patient-specific implant (Resorb X-PSI) allows precise surgery for FOA in craniosynostosis using a complete digital workflow and should be considered superior to manually bent resorbable plates. [ABSTRACT FROM AUTHOR]

Highlights • Zinc supplemented tissue shows increased free Zn fluorescence in the hippocampus. • Perfused tissue shows decreased free Zn compared to fresh-frozen tissue. • Fixation of tissue can impact research conclusions linking behavior with metal levels. Abstract Background: Fixation of brain tissue is a common practice which allows preservation of tissue and aids in preventing structural and chemical abnormalities. However, fixation procedures may disrupt the levels of biometals such as zinc when compared to tissue that is fresh-frozen. Thus, we sought to determine if any differences in free-zinc levels exist between perfused and fresh-frozen tissue. Zinc is an essential biometal critical for cellular communication and memory and exists in both bound and free forms; the latter playing critical roles in synaptic communication. New method: C57BL/6 J mice were divided into two water types: those given lab water and those given water supplemented with 10 ppm zinc carbonate. Perfusion was carried out with 4% paraformaldehyde on half of the animals in each water group to assess the impact on levels of free Zn as measured through Zinpyr-1 fluorescence. Results: There were significant differences in Zn fluorescence values between Zn-supplemented and lab water groups as well as between perfused and fresh-frozen tissues in the dentate gyrus and CA3 regions of the hippocampus, regions critical in learning & memory. Comparison with existing methods: These results show that when determining a method for euthanasia, any future histological techniques involving assessment of metal content should first be considered. Conclusions: Researchers must be cautious with the way in which tissue is collected and treated since this can lead to misleading conclusions when linking changes in behavior and relative levels of trace metals. [ABSTRACT FROM AUTHOR]

Tissue-mimicking phantoms are employed for the assessment of shocked histotripsy pulses in vitro. These broadband shock waves are critical for tissue ablation and are influenced by the frequency-dependent attenuation of the medium. The density, sound speed and attenuation spectra (2-25 MHz) were measured for phantoms that mimic key histotripsy targets. The influence of non-linear propagation relative to the attenuation was described in terms of Gol'dberg number. An expression was derived to estimate the bandwidth of shocked histotripsy pulses for power law-dependent attenuation. The expression is independent of the fundamental frequency of the histotripsy pulse for linear frequency-dependent attenuation. [ABSTRACT FROM AUTHOR]