1,237 research outputs found

    The orbit space of groupoids whose C∗C^*-algebras are GCR

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    Let GG be second countable locally compact Hausdorff groupoid with a continuous Haar system. We remove the assumption of amenability in a theorem by Clark about GCR groupoid C∗C^*-algebras. We show that if the groupoid C∗C^*-algebra of GG is GCR then the orbits of GG are locally closed.Comment: 1

    Paraoxonase1 Genetic Polymorphisms in a Mixed Ancestry African Population

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    Paraoxonase 1 (PON1) activity is markedly influenced by coding polymorphisms, Q/R at position 192 and M/L at position 55 of the PON1 gene. We investigated the frequencies of these polymorphisms and their effects on PON1 and antioxidant activities in 844 South African mixed ancestry individuals. Genotyping was done using allele-specific TaqMan technology, PON1 activities were measured using paraoxon and phenylacetate, oxidative status was determined by measuring the antioxidant activities of ferric reducing antioxidant power and trolox equivalent antioxidant capacity, and lipid peroxidation markers included malondialdehyde and oxidized LDL. The frequencies of Q192R and L55M were 47.6% and 28.8%, respectively, and the most common corresponding alleles were 192R (60.4%) and 55M (82.6%). The Q192 was significantly associated with 5.8 units’ increase in PON1 concentration and 15.4 units’ decrease in PONase activity after adjustment for age, sex, BMI, and diabetes, with suggestion of differential effects by diabetes status. The PON1 L55 variant was associated with none of the measured indices. In conclusion, we have shown that the Q192R polymorphism is a determinant of both PON1 concentration and activity and this association appeared to be enhanced in subjects with diabetes

    A translational rat model for ex vivo lung perfusion of pre-injured lungs after brain death

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    The process of brain death (BD) detrimentally affects donor lung quality. Ex vivo lung perfusion (EVLP) is a technique originally designed to evaluate marginal donor lungs. Nowadays, its potential as a treatment platform to repair damaged donor lungs is increasingly studied in experimental models. Rat models for EVLP have been described in literature before, yet the pathophysiology of BD was not included in these protocols and prolonged perfusion over 3 hours without anti-inflammatory additives was not achieved. We aimed to establish a model for prolonged EVLP of rat lungs from brain-dead donors, to provide a reliable platform for future experimental studies. Rat lungs were randomly assigned to one of four experimental groups (n = 7/group): 1) healthy, directly procured lungs, 2) lungs procured from rats subjected to 3 hours of BD and 1 hour cold storage (CS), 3) healthy, directly procured lungs subjected to 6 hours EVLP and 4), lungs procured from rats subjected to 3 hours of BD, 1 hour CS and 6 hours EVLP. Lungs from brain-dead rats showed deteriorated ventilation parameters and augmented lung damage when compared to healthy controls, in accordance with the pathophysiology of BD. Subsequent ex vivo perfusion for 6 hours was achieved, both for lungs of healthy donor rats as for pre-injured donor lungs from brain-dead rats. The worsened quality of lungs from brain-dead donors was evident during EVLP as well, as corroborated by deteriorated ventilation performance, increased lactate production and augmented inflammatory status during EVLP. In conclusion, we established a stable model for prolonged EVLP of pre-injured lungs from brain-dead donor rats. In this report we describe tips and pitfalls in the establishment of the rat EVLP model, to enhance reproducibility by other researchers

    Optimal waist-to-height ratio values for cardiometabolic risk screening in an ethnically diverse sample of South African urban and rural school boys and girls

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    BACKGROUND: The proposed waist-to-height ratio (WHtR) cut-off of 0.5 is less optimal for cardiometabolic risk screening in children in many settings. The purpose of this study was to determine the optimal WHtR for children from South Africa, and investigate variations by gender, ethnicity and residence in the achieved value. METHODS: Metabolic syndrome (MetS) components were measured in 1272 randomly selected learners, aged 10-16 years, comprising of 446 black Africans, 696 mixed-ancestry and 130 Caucasians. The Youden's index and the closest-top-left (CTL) point approaches were used to derive WHtR cut-offs for diagnosing any two MetS components, excluding the waist circumference. RESULTS: The two approaches yielded similar cut-off in girls, 0.465 (sensitivity 50.0, specificity 69.5), but two different values in boys, 0.455 (42.9, 88.4) and 0.425 (60.3, 67.7) based on the Youden's index and the CTL point, respectively. Furthermore, WHtR cut-off values derived differed substantially amongst the regions and ethnic groups investigated, whereby the highest cut-off was observed in semi-rural and white children, respectively, Youden's index0.505 (31.6, 87.1) and CTL point 0.475 (44.4, 75.9). CONCLUSION: The WHtR cut-off of 0.5 is less accurate for screening cardiovascular risk in South African children. The optimal value in this setting is likely gender and ethnicity-specific and sensitive to urbanization

    Ex Situ Perfusion of Hearts Donated After Euthanasia:A Promising Contribution to Heart Transplantation

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    Organ donation after euthanasia is performed in an increasing number of countries. In this donation after circulatory death procedure, it has not been possible to donate the heart. Recent literature, however, reports positive results of heart donation after circulatory death. Therefore, patients who donate organs following euthanasia might be suitable candidates for heart donation. We want to confirm this assumption by sharing the results of 2 cases of heart donation following euthanasia with ex situ subnormothermic heart preservation. Our aim is to raise awareness of the potential of heart donation following euthanasia for both clinical transplantation and research. METHODS. The data of 2 consecutive heart donations following euthanasia were collected prospectively. Informed consent was obtained from the patients themselves for heart donation for research purposes. An acellular oxygenated subnormothermic machine perfusion strategy was used to preserve both donor hearts. Subsequently, the hearts were evaluated on a normothermic perfusion machine using a balloon in the left ventricle. RESULTS. Heart donation following euthanasia was feasible without significant changes in existing retrieval protocols. Duration of machine perfusion preservation was 408 and 432 minutes, for heart 1 and 2, respectively. For heart 1, developed pressure (P(dev)) was 119 mm Hg, maximal rate of pressure rise (dP/dt(max)), and fall (dP/dt(min)) were 1524 mm Hg/s and −1057 mm Hg/s, respectively. For heart 2, P(dev) was 142 mm Hg, dP/dt(max) was 1098 mm Hg/s, and dP/dt(min) was −802 mm Hg/s. CONCLUSIONS. Hearts donated following euthanasia are highly valuable for research purposes and can have sufficient quality to be transplanted. With the implementation of ex situ heart perfusion, patients who are to donate their organs following euthanasia should also be able to donate their hearts. The complex combination of euthanasia and heart donation is ethically sound and surgically feasible and can contribute to shortening the heart transplant waiting list

    Association between dental and periodontal conditions with chronic kidney disease: A cross-sectional analysis of urban South Africans

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    Oral diseases are preventable causes of poor health outcomes in people with chronic kidney disease (CKD). Investigate the association between dental and periodontal conditions with kidney function and determine whether inflammation mediate the association between periodontitis and CKD. Cross-sectional analysis of 1551 South African adults of mixed ancestry. CKD was classified as estimated glomerular filtration rate (eGFR) <60mL/min/1.73m2. Oral profile was captured by decayed, missing, filled teeth index (DMFTi), bleeding on probing (BOP), pocket depth (PD), clinical attachment loss (CAL), and periodontitis classified as PD ≥4 mm.Overall, 6% had CKD, with 93% and 66% of participants with and without CKD, respectively having a high DMFTi (p<0.0001). Further, 84% (CKD) and 43% (without CKD) were edentulous (p<0.0001). A great proportion of the dentate sub-sample (n=846) had periodontitis, however, BOP, PD ≥4mm and CAL ≥4mm were similar between the groups. DMFTi was associated with eGFR and prevalent CKD (p<0.023), with this association driven by the Missing component. Periodontitis was not associated with eGFR nor CKD (p>0.282). In routine care of people with CKD, attention should be given to oral health
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