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Background Osteochondral allografting is an option for successful treatment of large articular cartilage defects. Use of osteochondral allografting is limited by graft availability, often because of loss of chondrocyte viability during storage. Questions/purposes The purpose of this study was to compare osteochondral allografts implanted in canine knees after 28 days or 60 days of storage for (1) initial (1 week) safety and feasibility; (2) integrity and positioning with time (12 weeks and 6 months); and (3) gross, cell viability, histologic, biochemical, and biomechanical characteristics at an endpoint of 6 months. Methods With Institutional Animal Care and Use Committee approval, adult dogs (n = 16) were implanted with 8-mm cylindrical osteochondral allografts in the lateral and medial femoral condyles of one knee. Osteochondral allografts preserved for 28 or 60 days using either the current tissue bank standard-of-care (SOC) or a novel system (The Missouri Osteochondral Allograft Preservation System, or MOPS) were used, creating four treatment groups: SOC 28-day, MOPS 28-day, SOC 60-day, and MOPS 60-day. Bacteriologic analysis of tissue culture and media were performed. Dogs were assessed by radiographs and arthroscopy at interim times and by gross, cell viability, histology, biochemistry, and biomechanical testing at the 6-month endpoint. Results With the numbers available, there was no difference in infection frequency during storage (5% for SOC and 3% for MOPS; p = 0.5). No infected graft was implanted and no infections occurred in vivo. MOPS grafts had greater chondrocyte viability at Day 60 (90% versus 53%; p = 0.002). For 60-day storage, MOPS grafts were as good as or better than SOC grafts with respect to all outcome measures assessed 6 months after implantation. Conclusions Donor chondrocyte viability is important for osteochondral allograft success. MOPS allows preservation of chondrocyte viability for up to 60 days at sufficient levels to result in successful outcomes in a canine model of large femoral condylar articular defects. Clinical Relevance These findings provide a promising development in osteochondral allograft technology that can benefit the quantity of grafts available for use and the quality of grafts being implanted.

Accurate characterization of the mechanical properties of brain tissue is essential for understanding the mechanisms of traumatic brain injuries and developing protective gears or facilities. However, how storage conditions might affect the mechanical properties of brain tissue remains unclear. The objective of this study is to investigate the effect of in vitro storage duration on the mechanical performance of brain tissue since measurements are usually carried out in vitro . Differential Scanning Calorimetry (DSC) measurements and uniaxial compression mechanical experiments are carried out. The results indicate that, for brain tissue stored at 1 °C without any liquid medium, the bio-molecular interactions and the mechanical strength of both white and grey matter deteriorate with prolonged storage duration. Transmission Electron Microscopy (TEM) results reveal the degeneration of myelin sheaths and the vacuolization of cristae with prolonged storage duration, suggesting that the in vitro storage duration should be carefully controlled. The findings from this study might facilitate the development of guidelines and standards for the in vitro storage of brain tissue.

Purpose: Due to the COVID-19 pandemic, most of the eye banks have limited/stopped corneal collection, as this is a highly contagious disease. This has led to shortage of donor corneas worldwide. Glycerol preservation of tissue remains a viable option in this scenario. The objective is to compare fresh corneal tissue (FCT) with glycerol-preserved cornea (GPC) in emergency corneal transplantation. Methods: This was a retrospective cohort study conducted in a tertiary care centre of Uttarakhand. Medical records of the patients who underwent therapeutic penetrating keratoplasty (TPK) were reviewed. FCT group included patients who underwent TPK with fresh corneal tissue and GPC group included patients who underwent TPK with glycerol preserved cornea. The indications and outcomes of TPK in the terms of therapeutic success were analysed and compared between both the groups. Results: A total of 94 eyes of 91 patients underwent TPK from October 2011 to August 2017. FCT group included 60 eyes of 57 patients and GPC group included 34 eyes of 34 patients. The primary indication of TPK was infectious keratitis in both the groups (FCT-81.6%; GPC - 91.2%) There was no significant difference in the therapeutic success in both the groups (P = 0.741, Odds ratio- 1.59 with 95% CI- 0.39-6.44). Complications included glaucoma (FCT-21.7%; GPC- 35.2%) graft infection (FCT- 18.33% GPC- 2.9%); graft rejection (FCT-11.66%, GPC- 0%); and graft failure (FCT-88.33%, GPC-100%). Conclusion: The GPC is comparable to FCTs in therapeutic transplant and can be a useful interim procedure in saving the eyes in cases of infective keratitis in the time of crisis.

Carefully categorized postmortem human brains are crucial for research. The lack of generally accepted methods for processing human postmortem brains for research persists. Thus, brain banking is essential; however, it cannot be achieved at the cost of the teaching mission of the academic institution by routing brains away from residency programs, particularly when the autopsy rate is steadily decreasing. A consensus must be reached whereby a brain can be utilizable for diagnosis, research, and teaching. The best diagnostic categorization possible must be secured and the yield of samples for basic investigation maximized. This report focuses on integrated, novel methods currently applied at the New York Brain Bank, Columbia University, New York, which are designed to reach accurate neuropathological diagnosis, optimize the yield of samples, and process fresh-frozen samples suitable for a wide range of modern investigations. The brains donated for research are processed as soon as possible after death. The prosector must have a good command of the neuroanatomy, neuropathology, and the protocol. One half of each brain is immersed in formalin for performing the thorough neuropathologic evaluation, which is combined with the teaching task. The contralateral half is extensively dissected at the fresh state. The anatomical origin of each sample is recorded using the map of Brodmann for the cortical samples. The samples are frozen at −160°C, barcode labeled, and ready for immediate disbursement once categorized diagnostically. A rigorous organization of freezer space, coupled to an electronic tracking system with its attached software, fosters efficient access for retrieval within minutes of any specific frozen samples in storage. This report describes how this achievement is feasible with emphasis on the actual processing of brains donated for research.

Bone taphonomy is a widely investigated topic; however, few data are available concerning marine bone taphonomy, especially on remains recovered from great depths and with short post-mortem intervals. To date, few studies have evaluated the bony changes which occur in seawater compared to samples with different post-mortem histories, and none through a comparative analysis of different approaches. To this purpose, this pilot study aims to examine the influence of seawater on bone preservation compared to other depositional contexts by multiple perspectives. Forty-nine human bone samples (femurs or tibiae) recovered from different environments (sea water, fresh water, outdoor, burial in coffin) were compared by macroscopic, microscopic and bone densitometric approaches. In order to investigate organic and inorganic components, undecalcified and decalcified histology of thin sections was performed. The analyses revealed a well-preserved bone tissue both macroscopically (92%) and microscopically (97% and 95% for undecalcified and decalcified sections). No significant differences were detected from radiological densitometric investigations (BMD = 1.6 g/cm2 ± 0.1), except between old and young individuals (p value < 0.001). Differences were observed for body decomposition and few scavenged samples (3/15). However, even if slight variations were observed, no relation was recorded with the depositional contexts. We found a similar bone preservation in the four environments at the time of recovery, both macroscopically and microscopically, but also with radiological densitometric investigations. Our observations enriched the literature on bone taphonomy, providing data on bone tissue preservation in the early post-mortem period from a multidisciplinary perspective, paving the way for further studies on the topic.

Conservation of the genetic resources of endangered animals is crucial for future generations. The loggerhead sea turtle ( Caretta caretta ) is a critically endangered species, because of human hunting, hybridisation with other sea turtle species, and infectious diseases. In the present study, we established primary fibroblast cell lines from the loggerhead sea turtle, and showed its species specific chromosome number is 2 n  = 56, which is identical to that of the hawksbill and olive ridley sea turtles. We first showed that intensive hybridization among multiple sea turtle species caused due to the identical chromosome number, which allows existence of stable hybridization among the multiple sea turtle species. Expressions of human-derived mutant Cyclin-dependent kinase 4 (CDK4) and Cyclin D dramatically extended the cell culture period, when it was compared with the cell culture period of wild type cells. The recombinant fibroblast cell lines maintained the normal chromosome condition and morphology, indicating that, at the G1/S phase, the machinery to control the cellular proliferation is evolutionally conserved among various vertebrates. To our knowledge, this study is the first to demonstrate the functional conservation to overcome the negative feedback system to limit the turn over of the cell cycle between mammalian and reptiles. Our cell culture method will enable the sharing of cells from critically endangered animals as research materials.

Background/aimsScant consideration has been given to the variation in structure of the human amniotic membrane (AM) at source or to the significance such differences might have on its clinical transparency. Therefore, we applied our experience of quantifying corneal transparency to AM.MethodsFollowing elective caesarean, AM from areas of the fetal sac distal and proximal (ie, adjacent) to the placenta was compared with freeze-dried AM. The transmission of light through the AM samples was quantified spectrophotometrically; also, tissue thickness was measured by light microscopy and refractive index by refractometry.ResultsFreeze-dried and freeze-thawed AM samples distal and proximal to the placenta differed significantly in thickness, percentage transmission of visible light and refractive index. The thinnest tissue (freeze-dried AM) had the highest transmission spectra. The thickest tissue (freeze-thawed AM proximal to the placenta) had the highest refractive index. Using the direct summation of fields method to predict transparency from an equivalent thickness of corneal tissue, AM was found to be up to 85% as transparent as human cornea.ConclusionWhen preparing AM for ocular surface reconstruction within the visual field, consideration should be given to its original location from within the fetal sac and its method of preservation, as either can influence corneal transparency.

Effective cellular cryopreservation while maintaining high cell viability is achieved by preventing intracellular and extracellular ice crystal formation using the Cells Alive System (CAS), a programmed freezer that applies a magnetic field. Here, the optimal temperature settings of the CAS were determined using rat sciatic nerves as a model tissue. Firstly, it was found that Schwann cell survival was increased by pre-cooling the samples in the ice crystal formation zone, increasing the freeze–thaw speed, and freezing–thawing in a magnetic field. Secondly, the setting (intensity and frequency) of the magnetic field at freezing–thawing was changed, and the optimum magnetic field strength was determined by evaluating cell viability. At the set temperature excluding previous studies, the minimum temperature was set to − 50 °C and kept frozen for 15 min, and then thawed immediately. The highest cell viability (27%) was achieved at 0.67 mT (intensity 3 [29.6 V] and frequency setting 10 [60 Hz]). The effects of the freeze–thaw program were assessed using transplanted sciatic nerve tissues removed after 2, 4, and 8 weeks. Anterior tibial muscle wet weight increased at 8 weeks in the control (without freezing) and after freezing–thawing in a magnetic field, compared to that without a magnetic field. Fluorescence staining of the sciatic nerve with anti-S100 antibodies revealed that Schwann cell counts increased at the transplanted site (at 8 weeks) of nerves that were freeze–thawed in a magnetic field. Overall, the CAS prevented ice crystal formation in rat sciatic nerves and could be used to maintain cell viability during cryopreservation.

Postmortem preservation conditions may be one of factors contributing to wide material property variations in brain tissues in literature. The objective of present study was to determine the effects of preservation temperatures on high strain-rate material properties of brain tissues using the split Hopkinson pressure bar (SHPB). Porcine brains were harvested immediately after sacrifice, sliced into 2 mm thickness, preserved in ice cold (group A, 10 samples) and 37 °C (group B, 9 samples) saline solution and warmed to 37 °C just prior to the test. A SHPB with tube aluminum transmission bar and semi-conductor strain gauges were used to enhance transmitted wave signals. Data were gathered using a digital acquisition system and processed to obtain stress–strain curves. All tests were conducted within 4 h postmortem. The mean strain-rate was 2487±72 s −1. A repeated measures model with specimen-level random effects was used to analyze log transformed stress–strain responses through the entire loading range. The mean stress–strain curves with ±95% confidence bands demonstrated typical power relationships with the power value of 2.4519 (standard error, 0.0436) for group A and 2.2657 (standard error, 0.0443) for group B, indicating that responses for the two groups are significantly different. Stresses and tangent moduli rose with increasing strain levels in both groups. These findings indicate that storage temperatures affected brain tissue material properties and preserving tissues at 37 °C produced a stiffer response at high strain-rates. Therefore, it is necessary to incorporate material properties obtained from appropriately preserved tissues to accurately predict the responses of brain using stress analyses models, such as finite element simulations.