Skin graft storage in platelet rich plasma (PRP).

Storage of skin grafts for later use is one of the standard applications in surgery. It is the most preferred method to maintain at +4°C in refrigeration after wrapping the surplus grafts into sterile gauze pad moistened with saline. Although there are many studies on the storage of skin grafts, less is known about storing skin grafts with PRP. Twenty-five pieces of 1 × 1 cm2 partial thickness skin graft were harvested from 12 patients during the reduction mammoplasty operation. Twenty-four grafts were divided into 4 groups, and each group consisted of 6 grafts, 1 graft was analyzed as Day 0. Grafts in Group 1, 2, and 3 were wrapped by sterile gauze pad moistened by either saline (Group 1) or Hartman (Group 2) or PRP (Group 3). Grafts were analyzed macroscopically and microscopically. There were no significant differences between media for the first 10 days. Decrease in viability was less in saline and PRP wrapped grafts at 20 day, viability decreased significantly in all environments after 20 days. Although there was no significant difference in saline or PRP storage, it was observed macroscopically that the grafts stored in the PRP appeared better.

Intermittent application of external positive pressure helps to preserve organ viability during ex vivo perfusion and culture.

The perfusion of medium through blood vessels allows the preservation of donor organs and culture of bioengineered organs. However, tissue damage due to inadequate perfusion remains a problem. We evaluated whether intermittent external pressurization would improve the perfusion and viability of organs in culture. A bioreactor system was used to perfuse and culture rat small intestine and femoral muscle preparations. Intermittent positive external pressure (10 mmHg) was applied for 20 s at intervals of 20 s. Intermittent pressurization resulted in uniform perfusion of small intestine preparations and minimal tissue damage after 20 h of perfusion, whereas non-pressurized (control) preparations exhibited significantly worse perfusion of the upper surface than the lower surface and histologic evidence of tissue damage. Longer term studies were undertaken in luciferase-expressing rat femoral muscle preparations. Compared with non-pressurized controls, intermittent pressurization led to better perfusion throughout the 14-day experimental period, improved organ viability as indicated by a higher bioluminescence intensity after perfusion with luciferin, and reduced levels of tissue necrosis with better preservation of vascular structures and skeletal muscle nuclei (histologic analyses). Therefore, intermittent application of external positive pressure improved the perfusion of small intestine and skeletal muscle preparations and enhanced tissue viability when compared with controls. We anticipate that this innovative perfusion technique could be used to improve the preservation of donor organs and culture of bioengineered organs.

The tissue viability imaging system-Suitable method for discovering minimal skin changes in occupational screenings? Results of a cross-sectional field study.

BACKGROUND: For early detection of initial skin changes in occupational screenings, only few objective assessment systems are available. OBJECTIVES: With the aim of assessing an objective measurement method for hand eczema, we trialed the application of the tissue viability imaging (TiVi) system, quantifying erythema non-invasively by polarized light spectroscopy. MATERIALS AND METHODS: In a field study with 625 employees of a semiconductor production company, 411 were exposed to prolonged wearing of occlusive gloves in the clean room. TiVi system and Hand Eczema Score for Occupational Screenings (HEROS), a quantitative skin score for the hands, were used, supplemented by a standardized personal interview. RESULTS: TiVi values of 65 up to 246 for each hand (palm or back), for each participant summed to overall 289 up to 848 (median 389), were measured. Higher TiVi values were noted for men, smokers, and with increasing age. Correlation between TiVi and HEROS was only weak. Several factors like skin pigmentation, thickness of the skin, or tattoos seem to influence TiVi results. CONCLUSIONS: The practical relevance of one-time measurements with the TiVi system in occupational screenings seems to be limited. Specifically, the TiVi system cannot replace dermatological examinations at the workplace. Notwithstanding, the application for other scientific purposes might be useful.

A Systematic Review of Testicle Survival Time After a Torsion Event.

BACKGROUND: The time window for possible salvage and survival of a torsed testicle is commonly thought to be 6 to 8 hours. However, survival of torsed testicles with or without subsequent atrophy is known to occur outside that critical time window. In this article, we performed a systematic review of the English literature to provide a more accurate understanding of reported time frames of testicle survival after a torsion event. OBJECTIVES: The primary research question was to determine the relationship between time to treatment and the rate of survival for testicles of male patients presenting with testicular torsion (TT). METHODS: A systematic review of the literature was performed and structured according to PRISMA guidelines. An exhaustive library search was performed after search strategies were developed for multiple databases that included PubMed, Cochrane library, Ovid MEDLINE, Web of Science, and ProQuest Theses and Dissertations. Two different searches were developed including "testicular torsion" and TT with the search term "time" added. Articles specifically reporting TT case series, testicle outcomes, and time to surgical or manual treatment were selected for review. In addition to and preceding the systematic review, an exhaustive manual search of the literature was also performed by the authors. As a result of these searches, a total of 30 studies with data considered relevant to the research question were included. The information extracted from the articles was tabulated with regard to time intervals to treatment and survival outcome. RESULTS: The systematic review process and protocol are reported in this article. A total of 30 studies were found that reported case series of TT patients and their outcomes as well as time to treatment reported in useful time frames. From these reports, a total of 2116 TT patients were culled, and their outcomes and time to treatment are reported. Because the time to treatment was reported variously in different case series, the 3 most common formats for reporting time to treatment and outcome were used. When overlap between the tables existed, the data were tallied and reported cumulatively. When reported in 6-hour intervals (1,283 patients), survival at 0 to 6 hours was 97.2%; 7 to 12 hours, 79.3%; 13 to 18 hours, 61.3%; 19 to 24 hours, 42.5%; 25 to 48 hours, 24.4%; and greater than 48 hours, 7.4%. Moreover, we reported cumulative survival data based on reporting for all 3 groups of patients. Testicular salvage in the first 12 hours is 90.4%, from 13 to 24 hours survival is 54.0%, and beyond 24 hours survival is 18.1%. Testicle survival after TT was significant beyond the commonly held 6 to 8 hour time frame and even after more than 24 hours of ischemia. CONCLUSIONS: Survival of the testicle irrespective of subsequent atrophy, decreased spermatogenesis or impaired endocrine function after TT can be much longer than the 6 to 8 hours that is commonly taught. Our systematic review of the literature demonstrates that survival percentages are significant even past 24 hours of torsion. This information should encourage aggressive management of patients presenting with TT pain that has been ongoing for many hours.

Friction Injury Versus Deep Tissue Injury: Level of Tissue Involvement: A Comparison of 2 Cases.

BACKGROUND: Friction injuries are postulated to be caused by acute or chronic abrasive/friction forces during sliding, scooting, or slouching behaviors prevalent in individuals with impaired mobility and particularly when transferring and repositioning. CASES: Patient histories for 2 cases were collected for determination of wound etiology. Outpatient wound clinic visits including photographic documentation for both cases were reviewed, compared, and contrasted for level of tissue involvement with each wound type/etiology. With serial sharp debridement of both wounds, differences were noted in level of tissue involvement/destruction. Healing progression and scarring were also different for both wounds. CONCLUSION: A comparison of 2 cases is presented to compare and contrast level of tissue involvement and destruction in an acute friction injury (top-down) versus a deep tissue injury (bottom-up). The importance of knowing a wound's history is critical for accurate diagnosis and coding.

Phospholipase Dα1-mediated phosphatidic acid change is a key determinant of desiccation-induced viability loss in seeds.

High sensitivity of seeds to water loss is a widespread phenomenon in the world's plant species. The molecular basis of this trait is poorly understood but thought to be associated with critical changes in membrane function. We profiled membrane lipids of seeds in eight species with varying levels of desiccation tolerance and found a close association between reducing seed viability and increasing phosphatidic acid (PA). We applied hydration-dehydration cycles to Arabidopsis seeds, which are normally desiccation tolerant, to mimic the onset of desiccation sensitivity with progression towards germination and examined the role of phospholipase D (PLD) in desiccation stress-induced production of PA. We found that PLDα1 became more abundant and migrated from the cytosol to the membrane during desiccation, whereas PLDδ did not change, and that all desiccation-induced PA was derived from PLDα1 hydrolysis. When PLDα1 was suppressed, the germination level after each hydration-dehydration cycle improved significantly. We further demonstrated that PLDα1-mediated PA formation modulates desiccation sensitivity as applying its inhibitor improved seed desiccation tolerance and its suppression in protoplasts enhanced survival under dehydration. The insights provided by comparative lipidomics enable us to propose a new membrane-based model for seed desiccation stress and survival.

Organ reserve, excess metabolic capacity, and aging.

"Organ reserve" refers to the ability of an organ to successfully return to its original physiological state following repeated episodes of stress. Clinical evidence shows that organ reserve correlates with the ability of older adults to cope with an added workload or stress, suggesting a role in the process of aging. Although organ reserve is well documented clinically, it is not clearly defined at the molecular level. Interestingly, several metabolic pathways exhibit excess metabolic capacities (e.g., bioenergetics pathway, antioxidants system, plasticity). These pathways comprise molecular components that have an excess of quantity and/or activity than that required for basic physiological demand in vivo (e.g., mitochondrial complex IV or glycolytic enzymes). We propose that the excess in mtDNA copy number and tandem DNA repeats of telomeres are additional examples of intrinsically embedded structural components that could comprise excess capacity. These excess capacities may grant intermediary metabolism the ability to instantly cope with, or manage, added workload or stress. Therefore, excess metabolic capacities could be viewed as an innate mechanism of adaptability that substantiates organ reserve and contributes to the cellular defense systems. If metabolic excess capacities or organ reserves are impaired or exhausted, the ability of the cell to cope with stress is reduced. Under these circumstances cell senescence, transformation, or death occurs. In this review, we discuss excess metabolic and structural capacities as integrated metabolic pathways in relation to organ reserve and cellular aging.

Angiotensin-(1-7) attenuates organ injury and mortality in rats with polymicrobial sepsis.

BACKGROUND: Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination. RESULTS: Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05). CONCLUSIONS: In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.

Lack of the α1,3-Fucosyltransferase Gene (Osfuct) Affects Anther Development and Pollen Viability in Rice.

N-linked glycosylation is one of the key post-translational modifications. α1,3-Fucosyltransferase (OsFucT) is responsible for transferring α1,3-linked fucose residues to the glycoprotein N-glycan in plants. We characterized an Osfuct mutant that displayed pleiotropic developmental defects, such as impaired anther and pollen development, diminished growth, shorter plant height, fewer tillers, and shorter panicle length and internodes under field conditions. In addition, the anthers were curved, the pollen grains were shriveled, and pollen viability and pollen number per anther decreased dramatically in the mutant. Matrix-assisted laser desorption/ionization time-of-flight analyses of the N-glycans revealed that α1,3-fucose was lacking in the N-glycan structure of the mutant. Mutant complementation revealed that the phenotype was caused by loss of Osfuct function. Transcriptome profiling also showed that several genes essential for plant developmental processes were significantly altered in the mutant, including protein kinases, transcription factors, genes involved in metabolism, genes related to protein synthesis, and hypothetical proteins. Moreover, the mutant exhibited sensitivity to an increased concentration of salt. This study facilitates a further understanding of the function of genes mediating N-glycan modification and anther and pollen development in rice.

Developing the tissue viability seating guidelines.

BACKGROUND: Costs for the prevention and management of pressure ulcers have increased significantly with limited published advice from health and social care organisations on seating and preventing pressure ulcers. At the request of the UK Tissue Viability Society the aim of the publication was to develop a practical guide for people, carers and health and social care professionals on how the research and evidence base on pressure ulcer prevention and management can be applied to those who remain seated for extended periods of time. METHODS AND FINDINGS: The evidence base informing the guidelines was obtained by applying a triangulation of methods: a literature review, listening event and stakeholder group consultation. The purpose was to engage users and carers, academics, clinicians, inspectorate and charities, with an interest in seating, positioning and pressure management to: gather views, feedback, stories, and evidence of the current practices in the field to create a greater awareness of the issue. CONCLUSION: The new guidelines are inclusive of all people with short and long-term mobility issues to include all population groups. The document includes evidence on where pressure ulcers develop when seated, risk factors, best possible seated position and what seat adjustments are required, the ideal seating assessment, interventions, self-help suggestions and key seating outcomes. The updated TVS CPGs have been informed by the best available evidence, the insights and wisdom of experts, stakeholders and people who spend extended periods of time sitting.

Improving the histologic characterization of burn depth.

BACKGROUND: Visual assessment of burn wound appearance is the standard of care to determine the depth of thermal injury but often incorrectly predicts wound healing potential. Histologic evaluation of hematoxylin and eosin (H&E) stained burn tissue is prone to subjectivity and is challenging for the novice. Lactate dehydrogenase (LDH) staining may offer a simplified and consistent technique to identify burn tissue viability. METHODS: Thirty tissue samples were obtained from 6 patients undergoing surgical excision for clinically determined deep partial thickness or full thickness burns. Tissues were stained with H&E or LDH. Each specimen was scored by 3 individuals with varying levels of skill in histologic interpretation using a standardized checklist at 2 distinct time points. RESULTS: Agreement within raters was highest for the expert rater and lowest for the novice; however, the LDH stained tissue method had improved agreement for an experienced burn surgeon and novice. Agreement between raters was greater for the LDH stained samples which were determined to have greater viability than the corresponding H&E section in 100% of samples scored by the expert and in 80% for the novice clinician. CONCLUSION: LDH staining offers a more consistent measure of tissue viability that can be used by experienced and novice clinicians.

Long distance heart transplantation: a tale of two cities.

In this 'paired' case report, we describe two heart transplants performed 3 days apart at our centre. Both cases involved very prolonged transportation time of the donor heart. In one case, the donor heart was transported in an ice chest, while in the other case the organ was transported using a normothermic ex vivo perfusion (NEVP) system. The additional retrieval costs incurred by the use NEVP were more than offset by the reduction in subsequent inpatient costs.

Viability and Biomechanics of Bare Diced Cartilage Grafts in Experimental Study.

OBJECTIVE: To assess the viability and biomechanics of bare diced cartilage grafts. METHODS: Cartilage samples were collected from 1 ear in 15 rabbits as well as costal cartilage. Each rabbit was inserted bare diced- and single-strip costal-cartilage grafts, respectively, into paraspinal subcutaneous pockets: after euthanasia at 2 months, specimens were weighed, with diced cartilage grafts examined histomorphologically by hematoxylin-eosin staining, masson trichrome staining, and immunohistochemistry. Finally, biomechanical properties of grafts were assessed. RESULTS: Bare diced cartilage grafts were connected into an integrated mass after 2 months, and inward growth of fibrous tissues and angiogenesis were observed. Mean wet weights of diced cartilage grafts were 1.603 ±â€Š0.278 and 1.662 ±â€Š0.204 g pre- and postoperation, respectively; those of costal cartilage grafts were 0.053 ±â€Š0.008 and 0.058 ±â€Š0.008 g, respectively. In compression assays, mean modulus values of elasticity at yield in diced- and costal-cartilage grafts were 7.65 ±â€Š0.59 and 22.30 ±â€Š1.15 MPa, respectively (P < 0.05); mean stress values were 4.07 ±â€Š0.38 and 12.50 ±â€Š1.15 MPa, respectively (P < 0.05). In the tensile test, mean modulus values of elasticity at yield of diced- and costal-cartilage grafts were 4.70 ±â€Š0.78 and 10.59 ±â€Š1.39 MPa, respectively (P < 0.05), mean stress values were 0.82 ±â€Š0.05 and 1.76 ±â€Š0.21 MPa, respectively (P < 0.05). CONCLUSIONS: Diced cartilage grafts had favorable viability and growth. Despite reduced elasticity and stress values, they still can be served as substitute for supportive filling materials.

Viability and Biomechanics of Diced Cartilage Blended With Platelet-Rich Plasma and Wrapped With Poly (Lactic-Co-Glycolic) Acid Membrane.

OBJECTIVES: The objective of this study was to investigate the viability and biomechanics of diced cartilage blended with platelet-rich plasma (PRP) and wrapped with poly (lactic-co-glycolic) acid (PLGA) membrane in a rabbit model. METHODS: A total of 10 New Zealand rabbits were used for the study. Cartilage grafts were harvested from 1 side ear. The grafts were divided into 3 groups for comparison: bare diced cartilage, diced cartilage wrapped with PLGA membrane, and diced cartilage blended with PRP and wrapped with PLGA membrane. Platelet-rich plasma was prepared using 8 mL of auricular blood. Three subcutaneous pockets were made in the backs of the rabbits, and the grafts were placed in these pockets. The subcutaneous implant tests were conducted for safety assessment of the PLGA membrane in vivo. All of the rabbits were sacrificed at the end of 3 months, and the specimens were collected. The sections were stained with hematoxylin and eosin, toluidin blue, and collagen II immunohistochemical. Simultaneously, biomechanical properties of grafts were assessed. RESULTS: This sample of PLGA membrane was conformed to the current standard of biological evaluation of medical devices. Moderate resorption was seen at the end of 3 months in the gross assessment in diced cartilage wrapped with PLGA membrane, while diced cartilage blended with PRP had no apparent resorption macroscopically and favorable viability in vivo after 3 months, and the histological parameters supported this. Stress-strain curves for the compression test indicated that the modulus of elasticity of bare diced cartilage was 7.65 ±â€Š0.59 MPa; diced cartilage wrapped with PLGA membrane was 5.98 ±â€Š0.45 MPa; and diced cartilage blended with PRP and wrapped with PLGA membrane was 7.48 ±â€Š0.55 MPa, respectively. CONCLUSIONS: Diced cartilage wrapped with PLGA membrane had moderate resorption macroscopically after 3 months. However, blending with PRP has beneficial effects in improving the viability of diced cartilages. Additionally, the compression modulus of diced cartilage blended with PRP and wrapped with PLGA membrane was similar to bare diced cartilage.

The effect of thawing protocols on follicle conservation in human ovarian tissue cryopreservation.

BACKGROUND: Ovarian tissue cryopreservation has the potential to improve fertility preservation for a growing number of patients undergoing sterilising therapy, particularly where oocyte or embryo cryopreservation is not suitable. However, its success is limited by significant follicular apoptosis upon thawing, and there is wide variation in thawing protocols used with little evidence of efficacy. OBJECTIVE: To determine the best warming rates to maintain tissue viability. MATERIALS AND METHODS: Ovarian tissue biopsies from 11 patients were taken with informed consent and divided into four pieces, which were allocated to either fresh assessment or to one of several freeze-thaw protocols. Cryopreservation was undertaken using a Stirling cycle cryo-cooler and cryopreserved samples were exposed to different warming protocols. Tissue conservation was then assessed using a marker, neutral red, to identify viable follicles. RESULTS: The results showed greatest follicle conservation rates in fresh samples, followed by those thawed using a rapid thawing protocol (Protocol 1). Tissue thawed using an ultra fast protocol (Protocol 2) and slow warming (Protocol 3) resulted in greater follicle loss. CONCLUSION: These preliminary results indicate thawing conditions significantly affect follicle conservation in cryopreserved human ovarian tissue.

The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review.

Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability.

Normothermic ex vivo perfusion provides superior organ preservation and enables viability assessment of hearts from DCD donors.

The shortage of donors in cardiac transplantation may be alleviated by the use of allografts from donation after circulatory death (DCD) donors. We have previously shown that hearts exposed to 30 min warm ischemic time and then flushed with Celsior supplemented with agents that activate ischemic postconditioning pathways, show complete recovery on a blood-perfused ex vivo working heart apparatus. In this study, these findings were assessed in a porcine orthotopic heart transplant model. DCD hearts were preserved with either normothermic ex vivo perfusion (NEVP) using a clinically approved device, or with standard cold storage (CS) for 4 h. Orthotopic transplantation into recipient animals was subsequently undertaken. Five of six hearts preserved with NEVP demonstrated favorable lactate profiles during NEVP and all five could be weaned off cardiopulmonary bypass posttransplant, compared with 0 of 3 hearts preserved with CS (p < 0.05, Fisher's exact test). In conclusion, DCD hearts flushed with supplemented Celsior solution and preserved with NEVP display viability before and after transplantation. Viability studies of human DCD hearts using NEVP are warranted.

Assessment of donor heart viability during ex vivo heart perfusion.

Ex vivo heart perfusion (EVHP) may facilitate resuscitation of discarded donor hearts and expand the donor pool; however, a reliable means of demonstrating organ viability prior to transplantation is required. Therefore, we sought to identify metabolic and functional parameters that predict myocardial performance during EVHP. To evaluate the parameters over a broad spectrum of organ function, we obtained hearts from 9 normal pigs and 37 donation after circulatory death pigs and perfused them ex vivo. Functional parameters obtained from a left ventricular conductance catheter, oxygen consumption, coronary vascular resistance, and lactate concentration were measured, and linear regression analyses were performed to identify which parameters best correlated with myocardial performance (cardiac index: mL·min(-1)·g(-1)). Functional parameters exhibited excellent correlation with myocardial performance and demonstrated high sensitivity and specificity for identifying hearts at risk of poor post-transplant function (ejection fraction: R(2) = 0.80, sensitivity = 1.00, specificity = 0.85; stroke work: R(2) = 0.76, sensitivity = 1.00, specificity = 0.77; minimum dP/dt: R(2) = 0.74, sensitivity = 1.00, specificity = 0.54; tau: R(2) = 0.51, sensitivity = 1.00, specificity = 0.92), whereas metabolic parameters were limited in their ability to predict myocardial performance (oxygen consumption: R(2) = 0.28; coronary vascular resistance: R(2) = 0.20; lactate concentration: R(2) = 0.02). We concluded that evaluation of functional parameters provides the best assessment of myocardial performance during EVHP, which highlights the need for an EVHP device capable of assessing the donor heart in a physiologic working mode.

Technical note: comparison of the PrestoBlue and LDH release assays with the MTT assay for skin viability assessment.

MTT assay is the gold standard for assessing skin sample viability but it is time-consuming. Here we compared the MTT test with two other assays for the assessment of skin viability. The MTT, PrestoBlue (colorimetric method) and LDH release assays were applied to fresh and cryopreserved skin. Skin viability was considered proportional to the optical density values of the relevant analytes. PrestoBlue did not reliably distinguish between fresh and cryopreserved skin. The LDH release assay did not allow us to establish a viability index. We recommend the MTT assay for assessing skin viability.

Approaches to preserve human osteochondral allografts.

Osteochondral defects may progress to osteoarthritis. Many attempts have been developed to overcome this issue, including osteochondral autografts and allografts. The goal of this study was to develop a new protocol for storage of human osteochondral allografts. Osteochondral plugs were randomly allocated in the following groups: control, immediate freezing up to -70 °C, cooling at 4 °C, and storage at 37 °C. Samples from the cooling at 4 °C and storage at 37 °C groups were stored in tubes containing medium plus human albumin and analyzed after 1, 3, and 14 days. The frozen groups' samples were cryopreserved for 1 year in cryotubes containing medium only (FM), medium plus human albumin (FA), and medium plus human albumin and glucose (FG) and were then analyzed. Analysis involved histological study with hematoxylin-eosin and Safranin O and a modified Live/Dead assay. In samples stored both at 37 and 4 °C, analysis showed statistically significant higher cellular mortality at 14 days compared to 1 and 3 days, but mortality in the 4 °C group was lower. In the freezing protocols, the FA group showed less cellular mortality than the FM and FG groups. Cooling at 4 °C offers better preservation capacity than storage at 37 °C, but both offer the capacity for preservation for 14 days. Adding human albumin to the storage medium is useful in reducing cellular mortality in samples frozen for 1 year.