A novel approach to determine the critical survival threshold of cellular oxygen within spheroids via integrating live/dead cell imaging with oxygen modeling.

Defining the oxygen level that induces cell death within 3-D tissues is vital for understanding tissue hypoxia; however, obtaining accurate measurements has been technically challenging. In this study, we introduce a noninvasive, high-throughput methodology to quantify critical survival partial oxygen pressure (pO2) with high spatial resolution within spheroids by using a combination of controlled hypoxic conditions, semiautomated live/dead cell imaging, and computational oxygen modeling. The oxygen-permeable, micropyramid patterned culture plates created a precisely controlled oxygen condition around the individual spheroid. Live/dead cell imaging provided the geometric information of the live/dead boundary within spheroids. Finally, computational oxygen modeling calculated the pO2 at the live/dead boundary within spheroids. As proof of concept, we determined the critical survival pO2 in two types of spheroids: isolated primary pancreatic islets and tumor-derived pseudoislets (2.43 ± 0.08 vs. 0.84 ± 0.04 mmHg), indicating higher hypoxia tolerance in pseudoislets due to their tumorigenic origin. We also applied this method for evaluating graft survival in cell transplantations for diabetes therapy, where hypoxia is a critical barrier to successful transplantation outcomes; thus, designing oxygenation strategies is required. Based on the elucidated critical survival pO2, 100% viability could be maintained in a typically sized primary islet under the tissue pO2 above 14.5 mmHg. This work presents a valuable tool that is potentially instrumental for fundamental hypoxia research. It offers insights into physiological responses to hypoxia among different cell types and may refine translational research in cell therapies.NEW & NOTEWORTHY Our study introduces an innovative combinatory approach for noninvasively determining the critical survival oxygen level of cells within small cell spheroids, which replicates a 3-D tissue environment, by seamlessly integrating three pivotal techniques: cell death induction under controlled oxygen conditions, semiautomated imaging that precisely identifies live/dead cells, and computational modeling of oxygen distribution. Notably, our method ensures high-throughput analysis applicable to various cell types, offering a versatile solution for researchers in diverse fields.

A scalable human islet 3D-culture platform maintains cell mass and function long-term for transplantation.

Present-day islet culture methods provide short-term maintenance of cell viability and function, limiting access to islet transplantation. Attempts to lengthen culture intervals remain unsuccessful. A new method was developed to permit the long-term culture of islets. Human islets were embedded in polysaccharide 3D-hydrogel in cell culture inserts or gas-permeable chambers with serum-free CMRL 1066 supplemented media for up to 8 weeks. The long-term cultured islets maintained better morphology, cell mass, and viability at 4 weeks than islets in conventional suspension culture. In fact, islets cultured in the 3D-hydrogel retained ß cell mass and function on par with freshly isolated islets in vitro and, when transplanted into diabetic mice, restored glucose balance similar to fresh islets. Using gas-permeable chambers, the 3D-hydrogel culture method was scaled up over 10-fold and maintained islet viability and function, although the cell mass recovery rate was 50%. Additional optimization of scale-up methods continues. If successful, this technology could afford flexibility and expand access to islet transplantation, especially single-donor islet-after-kidney transplantation.

Safety, tolerability, and pharmacokinetics of a single orally inhaled dose of PUR3100, a dry powder formulation of dihydroergotamine versus intravenous dihydroergotamine: A Phase 1 randomized, double-blind study in healthy adults.

BACKGROUND: Intravenous dihydroergotamine (DHE) has well-established efficacy for the acute treatment of migraine, but its use is limited by the need for in-hospital administration and the nausea/vomiting associated with a high maximum plasma concentration (Cmax). Inhalation is an alternative to intravenous dosing. The surface area of the lung allows for rapid absorption of a self-administered dose. OBJECTIVE: This study evaluated the safety, tolerability, and systemic pharmacokinetics (PK) of a dry powder formulation (PUR3100) DHE when delivered via inhalation compared to intravenous delivery. METHODS: In this double-blind, double-dummy Phase 1 study, healthy volunteers (N = 26) were randomized (1:1:1:1) to one of four groups: orally inhaled placebo plus intravenous DHE 1.0 mg or orally inhaled PUR3100 (0.5, 1.0, or 1.5 mg) plus intravenous placebo. Blood samples were drawn pre-dose and at time points post-dose over 48 h. Standard PK and safety parameters were assessed and values for Cmax and area under plasma concentration time curve (AUC) were used to assess comparative exposures of PUR3100 versus intravenous DHE. RESULTS: All doses of PUR3100 were associated with a lower incidence of nausea (21% vs. 86%), vomiting (0% vs. 29%), and headache (16% vs. 57%) compared to intravenous DHE. The PK profile of PUR3100 versus intravenous DHE was characterized by a similar mean time to Cmax (5 vs. 5.5 min), with reduced AUC0-2h (1120-4320 vs. 6340), and a lower Cmax (3620-14,400 vs. 45,000). Compared to intravenous DHE 1.0 mg, the highest nominal PUR3100 dose (1.5 mg), which delivers a fine-particle dose of approximately 0.9 mg to the lungs, had a geometric mean ratio percentage (90% confidence interval [CI]) for Cmax of 32% [17.2, 59.6] and AUC0-inf of 93% (62.9, 138.5), the latter of which was not significantly different. CONCLUSIONS: Inhaled PUR3100 is associated with rapid systemic PK within the therapeutic window and an improved safety profile relative to intravenous DHE.

Emergence of Coupled Rotor Dynamics in Metal-Organic Frameworks via Tuned Steric Interactions.

The organic components in metal-organic frameworks (MOFs) are unique: they are embedded in a crystalline lattice, yet, as they are separated from each other by tunable free space, a large variety of dynamic behavior can emerge. These rotational dynamics of the organic linkers are especially important due to their influence over properties such as gas adsorption and kinetics of guest release. To fully exploit linker rotation, such as in the form of molecular machines, it is necessary to engineer correlated linker dynamics to achieve their cooperative functional motion. Here, we show that for MIL-53, a topology with closely spaced rotors, the phenylene functionalization allows researchers to tune the rotors' steric environment, shifting linker rotation from completely static to rapid motions at frequencies above 100 MHz. For steric interactions that start to inhibit independent rotor motion, we identify for the first time the emergence of coupled rotation modes in linker dynamics. These findings pave the way for function-specific engineering of gear-like cooperative motion in MOFs.

Seven years on from the Canadian Airway Focus Group Difficult Airway Guidelines: an observational survey.

PURPOSE: Numerous clinical guidelines are available for management of the unanticipated difficult airway. It is unclear if practice recommendations are endorsed on regional, local, or individual levels. The objective of this observational study was to examine local and regional use of airway guidelines by anesthesiologists within a hospital partnership in Southwestern Ontario. METHODS: Using a paper survey, distributed locally to consultant and trainee anesthesiologists in a tertiary hospital, we examined individual clinical and educational practices regarding guideline use in airway management. Respondents were asked to report which published guideline they used for unanticipated airway difficulty. The effectiveness of dissemination of the national Canadian airway guidelines-the Canadian Airway Focus Group (CAFG) Difficult Airway Guidelines-was examined. We invited anesthesia department heads within the regional hospital partnership to complete an electronic survey investigating departmental adoption of guidelines. RESULTS: The response rate was 70% locally (79/112 anesthesiologists) and 52% regionally (11/21 department heads). Approximately 80% (64/79) of respondents reported using a formal clinical guideline if unanticipated difficulty with airway management was encountered. Seventy-two per cent of respondents (57/79) were aware of the published CAFG guidelines. Approximately 30% (16/51) of consultant anesthesiologists reported using the CAFG guidelines in clinical practice. Within the hospital partnership, 36% (4/11) of departments formally endorsed use of a specific airway management guideline. CONCLUSIONS: Despite widespread awareness of the national CAFG Difficult Airway Guidelines, they are not widely adopted in clinical practice. Further research is warranted to explore barriers to adoption of airway management guidelines for both individual anesthesiologists and anesthesia departments.

RéSUMé: OBJECTIF: De nombreuses lignes directrices cliniques sont disponibles pour la prise en charge des voies aériennes difficiles non anticipées. Nous ne savons pas si ces recommandations de pratique sont suivies aux niveaux régional, local ou individuel. L'objectif de cette étude observationnelle était d'examiner l'utilisation locale et régionale des lignes directrices sur les voies aériennes par des anesthésiologistes provenant d'un partenariat hospitalier dans le sud-ouest de l'Ontario. MéTHODE: À l'aide d'une enquête papier, distribuée localement aux anesthésiologistes et aux résidents en anesthésiologie d'un hôpital de soins tertiaires, nous avons examiné les pratiques cliniques et éducatives individuelles concernant l'utilisation des lignes directrices dans la prise en charge des voies aériennes. On a demandé aux répondants de divulguer les lignes directrices publiées qu'ils utilisaient lorsqu'ils étaient confrontés à des difficultés imprévues au niveau des voies aériennes. L'efficacité de diffusion des lignes directrices nationales canadiennes sur les voies aériennes­les Lignes directrices sur les voies aériennes difficiles du Canadian Airway Focus Group (CAFG)­a été examinée. Nous avons invité les chefs des départements d'anesthésiologie au sein du partenariat hospitalier régional à remplir un sondage électronique sur l'adoption des lignes directrices par leur département. RéSULTATS: Le taux de réponse était de 70 % au niveau local (79/112) et de 52 % au niveau régional (11/21 chefs de département). Environ 80 % (64/79) des répondants ont déclaré avoir utilisé des lignes directrices cliniques officielles en cas de difficultés imprévues dans la prise en charge des voies aériennes. Soixante-douze pour cent des répondants (57/79) avaient connaissance des lignes directrices publiées par le CAFG. Environ 30 % (16/51) des anesthésiologistes ont déclaré avoir utilisé les lignes directrices du CAFG dans leur pratique clinique. Au sein du partenariat hospitalier, 36 % (4/11) des départements ont officiellement appuyé l'utilisation d'une ligne directrice spécifique pour la prise en charge des voies aériennes. CONCLUSION: Malgré une importante sensibilisation aux Lignes directrices nationales sur les voies aériennes difficiles du CAFG, ces dernières ne sont pas largement adoptées dans la pratique clinique. D'autres recherches sont nécessaires pour explorer les obstacles à l'adoption de lignes directrices pour la prise en charge des voies aériennes tant par les anesthésiologistes que par les départements d'anesthésie.

Mentalizing Errors in Patients with Schizophrenia Who Received Psychosocial Rehabilitation: a Case-Control Study.

The main objective of this study was to evaluate the mentalizing performance of patients with schizophrenia who received daily psychosocial rehabilitation treatment compared with healthy controls. Differences in mentalizing performance between men and women, and the relationship between mentalizing deficits, cognitive impairment, symptoms, and global functioning of patients were also examined. A case-control study design was utilized (N = 95). Adults with schizophrenia were recruited from psychosocial rehabilitation clinics (n = 53) and healthy controls were recruited from the community (n = 42). Mentalizing was evaluated with the Movie for the Assessment of Social Cognition, an audiovisual measure with good ecological validity. Measures of cognitive functioning, symptoms, and global functioning were also administered. Patients exhibited significant mentalizing deficits. Specifically, patients made more undermentalizing errors and more no mentalizing errors compared with healthy controls. In patients and healthy controls, no differences were found between men and women in mentalizing abilities. In patients with schizophrenia, lower cognitive functioning (i.e., immediate and delayed verbal learning, verbal fluency, and processing speed) were associated with poorer mentalizing. In patients, processing speed explained 31% of the variance in total mentalizing errors and mentalizing deterioration was associated with poorer overall functioning. Psychosocial rehabilitation interventions in people with schizophrenia should consider mentalizing deficits (especially undermentalizing and no mentalizing difficulties) and their relationship with reduced processing speed in treatment delivery (e.g., direct and organized communication). Integration of treatments targeting mentalizing deficits in a psychosocial rehabilitation setting is recommended to improve functioning in schizophrenia.

Intermittent normobaric oxygen inhalation enhances subcutaneous prevascularization for cell transplantation.

PURPOSE: Subcutaneous tissue is a promising site for cell transplantation; advantages include minimally invasive procedures and easy post-transplant monitoring. However, limited vascularity is the major known challenge. To address this challenge, a prevascularized graft bed is prepared in recipients. We aimed to establish an improved, clinically applicable approach to promote prevascularization of the subcutaneous graft bed prior to cell transplantation. METHODS: We applied a conventional prevascularization approach by subcutaneously implanting nylon discs into the backs of Lewis rats. After disc implantation, we treated rats with or without intermittent normobaric 100% oxygen inhalation (1 h, twice a day, for consecutive 7 days). We used histology to compare vascular density between the oxygen-treated or control groups. To assess the functional effects of prevascularization, we transplanted three hundred islets isolated from luciferase-transgenic Lewis rats into the oxygen-treated or control wild type Lewis recipients, then used bioluminescence imaging to track engraftment for 4 weeks. RESULTS: Oxygen treatment significantly augmented prevascularization in the subcutaneous site compared to controls. Islet transplantation into prevascularized graft beds demonstrated significant improvement in engraftment efficiency in oxygen-treated recipients compared to controls at 2-4 weeks post-transplantation. CONCLUSION: Combining intermittent normobaric 100% oxygen inhalation with a conventional vascularization approach promotes a functional vasculature within a week. A simple approach using normobaric oxygen has the potential for translation into clinical application in subcutaneous site cell transplantations.

Overcoming Crystallinity Limitations of Aluminium Metal-Organic Frameworks by Oxalic Acid Modulated Synthesis.

A modulated synthesis approach based on the chelating properties of oxalic acid (H2 C2 O4 ) is presented as a robust and versatile method to achieve highly crystalline Al-based metal-organic frameworks. A comparative study on this method and the already established modulation by hydrofluoric acid was conducted using MIL-53 as test system. The superior performance of oxalic acid modulation in terms of crystallinity and absence of undesired impurities is explained by assessing the coordination modes of the two modulators and the structural features of the product. The validity of our approach was confirmed for a diverse set of Al-MOFs, namely X-MIL-53 (X=OH, CH3 O, Br, NO2 ), CAU-10, MIL-69, and Al(OH)ndc (ndc=1,4-naphtalenedicarboxylate), highlighting the potential benefits of extending the use of this modulator to other coordination materials.

A subcutaneous pancreatic islet transplantation platform using a clinically applicable, biodegradable Vicryl mesh scaffold - an experimental study.

Pancreatic islet transplantation into the liver is an effective treatment for type 1 diabetes but has some critical limitations. The subcutaneous site is a potential alternative transplant site, requiring minimally invasive procedures and allowing frequent graft monitoring; however, hypoxia is a major drawback. Our previous study without scaffolding demonstrated post-transplant graft aggregation in the subcutaneous site, which theoretically exacerbates lethal intra-graft hypoxia. In this study, we introduce a clinically applicable subcutaneous islet transplantation platform using a biodegradable Vicryl mesh scaffold to prevent aggregation in a diabetic rat model. Islets were sandwiched between layers of clinically proven Vicryl mesh within thrombin-fibrin gel. In vitro, the mesh prevented islet aggregation and intra-islet hypoxia, which significantly improved islet viability. In vivo rat syngeneic islet transplantations into a prevascularized subcutaneous pocket demonstrated that the mesh significantly enhanced engraftment, as measured by assays for graft survival and function. Histological examination at 6 weeks showed well-vascularized grafts sandwiched in a flat shape between the mesh layers. The biodegradable mesh was fully absorbed by three months, which alleviated chronic foreign body reaction and fibrosis, and supported long-term graft maintenance. This simple graft shape modification approach is an effective and clinically applicable strategy for improved subcutaneous islet transplantation.

Cost impact of introducing a treatment escalation/limitation plan during patients' last hospital admission before death.

OBJECTIVE: A recent study found that the use of a treatment escalation/limitation plan (TELP) was associated with a significant reduction in non-beneficial interventions (NBIs) and harms in patients admitted acutely who subsequently died. We quantify the economic benefit of the use of a TELP. DESIGN: NBIs were micro-costed. Mean costs for patients with a TELP were compared to patients without a TELP using generalized linear model regression, and results were extrapolated to the Scottish population. SETTING: Medical, surgical and intensive care units of district general hospital in Scotland, UK. PARTICIPANTS: Two hundred and eighty-seven consecutive patients who died over 3 months in 2017. Of these, death was 'expected' in 245 (85.4%) using Gold Standards Framework criteria. INTERVENTION: Treatment escalation/limitation plan. MAIN OUTCOME MEASURE: Between-group difference in estimated mean cost of NBIs. RESULTS: The group with a TELP (n = 152) had a mean reduction in hospital costs due to NBIs of GB £220.29 (US $;281.97) compared to those without a TELP (n = 132) (95% confidence intervals GB £323.31 (US $413.84) to GB £117.27 (US $150.11), P = <0.001). Assuming that a TELP could be put in place for all expected deaths in Scottish hospitals, the potential annual saving would be GB £2.4 million (US $3.1 million) from having a TELP in place for all 'expected' deaths in hospital. CONCLUSIONS: The use of a TELP in an acute hospital setting may result in a reduction in costs attributable to NBIs.

Effects of Physical Rehabilitation in Patients with Spinocerebellar Ataxia Type 7.

Today, neurorehabilitation has become in a widely used therapeutic approach in spinocerebellar ataxias; however, there are scarce powerful clinical studies supporting this notion, and these studies require extension to other specific SCA subtypes in order to be able to form conclusions concerning its beneficial effects. Therefore, in this study, we perform for the first time a case-control pilot randomized, single-blinded, cross-sectional, and observational study to evaluate the effects of physical neurorehabilitation on the clinical and biochemical features of patients with spinocerebellar ataxia type 7 (SCA7) in 18 patients diagnosed with SCA7. In agreement with the exercise regimen, the participants were assigned to groups as follows: (a) the intensive training group, (b) the moderate training group, and (c) the non-training group (control group).We found that both moderate and intensive training groups showed a reduction in SARA scores but not INAS scores, compared with the control group (p < 0.05). Furthermore, trained patients exhibited improvement in the SARA sub-scores in stance, gait, dysarthria, dysmetria, and tremor, as compared with the control group (p < 0.05). No significant improvements were found in daily living activities, as revealed by Barthel and Lawton scales (p > 0.05). Patients under physical training exhibited significantly decreased levels in lipid-damage biomarkers and malondialdehyde, as well as a significant increase in the activity of the antioxidant enzyme PON-1, compared with the control group (p < 0.05). Physical exercise improved some cerebellar characteristics and the oxidative state of patients with SCA7, which suggest a beneficial effect on the general health condition of patients.

Patient-Therapist Perspective of the Working Alliance in Psychotherapy.

This study aimed to examine perceptions of the working alliance in a sample of Spanish patients and therapists. The alliance was measured after the third and tenth psychotherapy sessions using patient and therapist versions of the Spanish adaptation of the Working Alliance Inventory (WAI). After both sessions, correlations between the patients' and therapists' ratings, both of total alliance and of the various dimensions of the alliance, were moderate at best. Moreover, after the third psychotherapy session, patients' scores for the total alliance and the Goal and Task subscales were significantly higher than the scores from their therapists in these dimensions. Following the tenth session, patient ratings exceeded those of their therapists only on the Task subscale. Finally, in contrast to the ratings of patients, therapists' alliance ratings increased significantly between the third and tenth sessions of psychotherapy. Certain recommendations are presented to improve the study of patient and therapist perceptions of the working alliance and to increase the convergence between them with regard to this central treatment variable.

Spanish adaptation of the Revised Helping Alliance Questionnaire (HAq-II).

BACKGROUND: The working or helping alliance is one of the most widely studied constructs in psychotherapy process research. AIM: The aim of this study was to adapt the patient and therapist forms of the Revised Helping Alliance Questionnaire II (HAq-II-P and HAq-II-T, respectively) into Spanish. METHOD: The two measurement instruments were adapted through a systematic translation process, a pilot study and a clinical study. The psychometric properties were examined following the third psychotherapy session. RESULTS: Mean scores on the Spanish-language HAq-II-P and HAq-II-T were high. The corrected item-total correlations for >94% of the items were >0.30. Cronbach's α values for internal consistency were 0.88 and 0.93, respectively. Correlations for convergent validity with the respective versions of the Spanish-language Working Alliance Inventory were 0.80 and 0.87, respectively. In terms of predictive validity, there was a significant correlation between HAq-II-T and the patients' residual gain scores on the Spanish-language Beck Depression Inventory after the tenth psychotherapy session. CONCLUSIONS: These results are consistent with studies using the original English versions of the HAq-II.

Reversal of diabetes by an oral Salmonella-based vaccine in acute and progressive diabetes in NOD mice.

Type 1 diabetes (T1D)-associated hyperglycemia develops, in part, from loss of insulin-secreting beta cells. The degree of glycemic dysregulation and the age at onset of disease can serve as indicators of the aggressiveness of the disease. Tracking blood glucose levels in prediabetic mice may demonstrate the onset of diabetes and, along with animal age, also presage disease severity. In this study, an analysis of blood glucose levels obtained from female NOD mice starting at 4 weeks until diabetes onset was undertaken. New onset diabetic mice were orally vaccinated with a Salmonella-based vaccine towards T1D-associated preproinsulin combined with TGFß and IL10 along with anti-CD3 antibody. Blood glucose levels were obtained before and after development of disease and vaccination. Animals were classified as acute disease if hyperglycemia was confirmed at a young age, while other animals were classified as progressive disease. The effectiveness of the oral T1D vaccine was greater in mice with progressive disease that had less glucose excursion compared to acute disease mice. Overall, the Salmonella-based vaccine reversed disease in 60% of the diabetic mice due, in part, to lessening of islet inflammation, improving residual beta cell health, and promoting tolerance. In summary, the age of disease onset and severity of glucose dysregulation in NOD mice predicted response to vaccine therapy. This suggests a similar disease categorization in the clinic may predict therapeutic response.

Mechanism of Action of Oral Salmonella-Based Vaccine to Prevent and Reverse Type 1 Diabetes in NOD Mice.

A combination therapy of preproinsulin (PPI) and immunomodulators (TGFß+IL10) orally delivered via genetically modified Salmonella and anti-CD3 promoted glucose balance in in NOD mice with recent onset diabetes. The Salmonella bacteria were modified to express the diabetes-associated antigen PPI controlled by a bacterial promoter in conjunction with over-expressed immunomodulating molecules. The possible mechanisms of action of this vaccine to limit autoimmune diabetes remained undefined. In mice, the vaccine prevented and reversed ongoing diabetes. The vaccine-mediated beneficial effects were associated with increased numbers of antigen-specific CD4+CD25+Foxp3+ Tregs, CD4+CD49b+LAG3+ Tr1-cells, and tolerogenic dendritic-cells (tol-DCs) in the spleens and lymphatic organs of treated mice. Despite this, the immune response to Salmonella infection was not altered. Furthermore, the vaccine effects were associated with a reduction in islet-infiltrating lymphocytes and an increase in the islet beta-cell mass. This was associated with increased serum levels of the tolerogenic cytokines (IL10, IL2, and IL13) and chemokine ligand 2 (CCL2) and decreased levels of inflammatory cytokines (IFNγ, GM-CSF, IL6, IL12, and TNFα) and chemokines (CXCL1, CXCL2, and CXCL5). Overall, the data suggest that the Salmonella-based vaccine modulates the immune response, reduces inflammation, and promotes tolerance specifically to an antigen involved in autoimmune diabetes.

A high burden of diabetes and ankle brachial index abnormalities exists in Mexican Americans in South Texas.

Ethnic differences exist in the United States in the interrelated problems of diabetes (DM), peripheral arterial disease (PAD), and leg amputations. The purpose of this study was to determine the prevalence and risk factor associations for subclinical PAD in a population sample of Mexican Americans using the ankle brachial (ABI) index. The ABI-High (higher of the two ankle pressures/highest brachial pressure) and ABI-Low (lower of the two ankle pressures/highest brachial pressure) were calculated to define PAD. Toe brachial index (TBI) was also calculated. 746 participants were included with an age of 53.4 ± 0.9 years, 28.3 % had diabetes mellitus (DM), 12.6 % were smokers, and 51.2 % had hypertension (HTN). Using ABI-High ≤ 0.9, the prevalence of PAD was 2.7 %. This rose to 12.7 % when an ABI-Low ≤ 0.9 was used; 4.0 % of the population had an ABI-High > 1.4. The prevalence of TBI < 0.7 was 3.9 %. DM was a significant risk factor for ABI-High ≤ 0.9 and ABI-High > 1.4, and TBI < 0.7. Increased age, HTN, smoking was associated with ABI-High ≤ 0.9, while being male was associated with ABI-High > 1.4. Increased age, smoking, and lower education were all associated with abnormal TBI. Despite relatively younger mean age than other studied Hispanic cohorts, the present population has a high burden of ABI abnormalities. DM was a consistent risk factor for PAD. These abnormalities indicate an important underlying substrate of vascular and metabolic disease that may predispose this population to the development of symptomatic PAD and incident amputations.

Biological hypoxia in pre-transplant human pancreatic islets induces transplant failure in diabetic mice.

Evaluating the quality of isolated human islets before transplantation is crucial for predicting the success in treating Type 1 diabetes. The current gold standard involves time-intensive in vivo transplantation into diabetic immunodeficient mice. Given the susceptibility of isolated islets to hypoxia, we hypothesized that hypoxia present in islets before transplantation could indicate compromised islet quality, potentially leading to unfavorable outcomes. To test this hypothesis, we analyzed expression of 39 hypoxia-related genes in human islets from 85 deceased donors. We correlated gene expression profiles with transplantation outcomes in 327 diabetic mice, each receiving 1200 islet equivalents grafted into the kidney capsule. Transplantation outcome was post-transplant glycemic control based on area under the curve of blood glucose over 4 weeks. In linear regression analysis, DDIT4 (R = 0.4971, P < 0.0001), SLC2A8 (R = 0.3531, P = 0.0009) and HK1 (R = 0.3444, P = 0.0012) had the highest correlation with transplantation outcome. A multiple regression model of 11 genes increased the correlation (R = 0.6117, P < 0.0001). We conclude that assessing pre-transplant hypoxia in human islets via gene expression analysis is a rapid, viable alternative to conventional in vivo assessments. This approach also underscores the importance of mitigating pre-transplant hypoxia in isolated islets to improve the success rate of islet transplantation.

Interactions between non-identical prion proteins.

Prion formation involves the conversion of soluble proteins into an infectious amyloid form. This process is highly specific, with prion aggregates templating the conversion of identical proteins. However, in some cases non-identical prion proteins can interact to promote or inhibit prion formation or propagation. These interactions affect both the efficiency with which prion diseases are transmitted across species and the normal physiology of yeast prion formation and propagation. Here we examine two types of heterologous prion interactions: interactions between related proteins from different species (the species barrier) and interactions between unrelated prion proteins within a single species. Interestingly, although very subtle changes in protein sequence can significantly reduce or eliminate cross-species prion transmission, in Saccharomyces cerevisiae completely unrelated prion proteins can interact to affect prion formation and propagation.