Coronary artery calcifications and diastolic dysfunction versus visceral fat area in type 1 diabetes: VISCERA study

Aims

Type 1 diabetic patients (T1DM) experience a higher cardiovascular disease and mortality risk than controls. We investigated whether visceral adipose tissue (VAT) contributes to coronary artery calcifications (CAC) and cardiac dysfunction in T1DM.

Genotoxicity of PM10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

The variation in the genotoxic potency of PM10 in vitro in relation to the particle source type was investigated. Particles were collected at one urban, one rural, and one industrial site in Flanders. Genotoxicity was assessed using four different in vitro test systems exposed to PM10 in suspension and to the organic extracts of PM10. Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test. In addition, the Comet assay and Micronucleus test were performed using human blood cells. Results show that exposure to PM10 and the organic extracts from both urban and industrial areas causes significant genetic damage. The Salmonella mutagenicity test was most suitable for the screening of PM10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes. Clear dose-response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter. The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m3. Results obtained in this study suggest that PM10 causes DNA damage and mutations. The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.     

TMP21 degradation is mediated by the ubiquitin‐proteasome pathway

The presenilin‐associated complex regulates two independent intramembranous cleavage activities, i.e. γ‐secretase and ε‐secretase activity. The γ‐secretase complex requires four critical components for its activity: presenilin 1, anterior pharynx‐defective 1, nicastrin 1 and presenilin enhancer 2, all of which are degraded through the ubiquitin‐proteasome pathway. Recently, TMP21, a type I transmembrane protein involved in endoplasmic reticulum/Golgi transport, was identified as a member of the presenilin complex. Knockdown of TMP21 selectively regulated pathogenic γ‐secretase activity, resulting in increased amyloid β protein 40 and 42, without affecting the ε‐cleavage of Notch. A further understanding of TMP21 degradation is required to examine the biological consequences of TMP21 protein level aberrations and their potential role in the pathogenesis of Alzheimer’s disease and drug development. Here we show that human TMP21 has a short half‐life of approximately 3 h. Treatment with proteasomal inhibitors can increase TMP21 protein levels in both a time‐ and dose‐dependent manner, and both co‐immunoprecipitation and immunofluorescent staining show that TMP21 is ubiquitinated. Inhibition of the lysosomal pathway failed to show a dose‐dependent increase in TMP21 protein levels. Taken together, these results indicate that the degradation of TMP21, as with the other presenilin‐associated γ‐secretase complex members, is mediated by the ubiquitin‐proteasome pathway.     

Increased post-thaw viability and phase I and II biotransformation activity in cryopreserved rat liver slices after improvement of a fast-freezing method.

An existing cryopreservation method for liver slices applies 12% dimethylsulfoxide and rapid freezing. We found that cells in rat liver slices cryopreserved in this manner deteriorated rapidly upon culturing. To improve this cryopreservation method, we varied the dimethylsulfoxide concentration (0, 12, 18, and 30%), the cryopreservation medium (Williams medium E, fetal calf serum, and University of Wisconsin medium), slice thickness, and the storage period at 4 degrees C during slice preparation before cryopreservation. After thawing, slices were cultured for 4 h at 37 degrees C before their viability was evaluated by their potassium content and the number of intact cells determined histomorphologically. The biotransformation capacity of liver slices cryopreserved by the improved method was assessed by testosterone oxidation, hydroxycoumarin sulfation, and glucuronidation. Best results were obtained with 18% dimethylsulfoxide in Williams medium E: the potassium content of cryopreserved slices was higher than 65%, and the number of intact cells was higher than 60% of that in fresh slices; with 12% dimethylsulfoxide, potassium content was less than 40%, and the number of intact cells was less than 30%. Results did not differ between the three cryopreservation media. Viability of thin slices (8-10 cell layers) was better maintained than that of thicker slices (>14 cell layers). Storage at 4 degrees C of slices before cryopreservation decreased viability after cryopreservation. Both oxidative and conjugation activities were better than 60% of fresh values. Although results varied, slices cryopreserved with this improved method and cultured for 4 h retained viability between 50 and 80%, and biotransformation activity between 60 and 90% of fresh slices.     

Comparison of the aqueous solubilization of practically insoluble niclosamide by polyamidoamine (PAMAM) dendrimers and cyclodextrins

This study is the first report of the solubilization of niclosamide by cyclodextrin complexation or the interaction between the drug and polyamidoamine (PAMAM) dendrimers. Half generation dendrimers with more polar carboxylate surface functional groups did not increase the solubility of niclosamide. From the phase solubility studies, when the fold enhancement in solubility of niclosamide combined with full generation amine terminated PAMAM dendrimers was compared with that obtained when the drug was combined with beta- or hydroxypropyl-beta-cyclodextrin, the results showed that, except for G-0 dendrimer at pH 7, the solubility of niclosamide was significantly higher in the presence of the dendrimers. In addition, higher equilibrium stability constants and complexation efficiency showed that the dendrimers formed stronger more stable complexes than the CDs. However, the strong interaction between the amine surface functional groups and the niclosamide molecule complexes caused a decrease in dissolution rate compared to the CDs because the interaction retarded the release of the drug from the dendrimers. In addition to increasing the solubility, PAMAM dendrimers therefore also offer the possible for the controlled release of the drug from solid dosage forms.     

Rapid and Successful Implementation of a COVID-19 Convalescent Plasma Programme—The South African Experience

Background: COVID-19 convalescent plasma (CCP) has been considered internationally as a treatment option for COVID-19. CCP refers to plasma collected from donors who have recovered from and made antibodies to SARS-CoV-2. To date, convalescent plasma has not been collected in South Africa. As other investigational therapies and vaccination were not widely accessible, there was an urgent need to implement a CCP manufacture programme to service South Africans. Methods: The South African National Blood Service and the Western Cape Blood Service implemented a CCP programme that included CCP collection, processing, testing and storage. CCP units were tested for SARS-CoV-2 Spike ELISA and neutralising antibodies and routine blood transfusion parameters. CCP units from previously pregnant females were tested for anti-HLA and anti-HNA antibodies. Results: A total of 987 CCP units were collected from 243 donors, with a median of three donations per donor. Half of the CCP units had neutralising antibody titres of >1:160. One CCP unit was positive on the TPHA serology. All CCP units tested for anti-HLA antibodies were positive. Conclusion: Within three months of the first COVID-19 diagnosis in South Africa, a fully operational CCP programme was set up across South Africa. The infrastructure and skills implemented will likely benefit South Africans in this and future pandemics.     

Has the character of gastric cancer changed? A descriptive study of a 10-year period

Over the 10-year period January 1976-December 1985, 446 patients with histologically verified adenocarcinoma of the stomach were treated at Tygerberg Hospital. Coloured patients made up 63.4% of the study population and a significant increase in the annual proportion of this group was observed. Coloured men comprised 47.6% of the total group. The mean age of white and coloured patients differed significantly (68.9 v. 56.5; P less than 0.001). The symptom complex was essentially similar in the two racial groups and in general the character of the symptoms had no bearing on the prevalence of resection. Although antral tumours were most common in whites and in coloureds, there was a significant increase in tumours located in the fundus in whites. The resection rate remained unchanged over the 10-year period. Only 4 cases of early gastric cancer were detected during this period without any signs of an increased yield of early lesions over time. This audit revealed no beneficial changes over time, which is in stark contrast with reports from Japan regarding the proportion of curable lesions.     

A South African mixed ancestry family with Huntington disease-like 2: clinical and genetic features.

Huntington disease-like 2 (HDL2) is a neurodegenerative disorder caused by an expansion of a CTG repeat in the junctophilin-3 gene (JPH3). A limited number of HDL2 families have been reported, all of apparently Black African ancestry. We report on a South African family that presented with progressive dementia and a movement disorder affecting numerous family members. Genotyping of the JPH3 CTG repeat revealed pathogenic expansions in three affected individuals. Whereas HDL2 is thought to be clinically indistinguishable from Huntington disease (HD), 2 of the patients in this study presented with clinical symptoms that differed substantially from HD; one had myoclonus and the other had Parkinsonism. Moreover, brain magnetic resonance imaging scans of these patients showed imaging features atypical for HD. Mitochondrial DNA and Y-chromosome DNA analysis on a family member showed that his maternal and paternal ancestries are typical of that found among the South African mixed ancestry or colored population. A difference in the distribution of CTG repeats between Caucasian and Black individuals was detected. We conclude that the phenotype of HDL2 is broad and can differ from that of typical HD. The diagnosis therefore should be considered in a wide spectrum of neuropsychiatric and abnormal movement presentations.     

Weight and health status of black female students.

OBJECTIVE: To examine black female students for the occurrence of risk factors associated with chronic diseases of lifestyle, namely obesity, hypertension, nicotine usage, dyslipidaemia and compromised mental health (depression). DESIGN: A cross-sectional analytical study design was used. All participants were examined within a period of 3 months during 1994. Weight, height, and hip and waist measurements were taken. Body mass index (BMI), waist-hip ratio (WHR) and waist circumference (WC) were calculated for each subject. Two systolic and diastolic blood pressure readings were taken for each participant. Questionnaires were used to determine specific risk factors related to lifestyle. The Beck Depression Inventory (BDI) was used to measure psychological well-being. Fasting blood samples were collected and analysed for serum lipids and iron status. SETTING: The University of the North in the Northern Province of South Africa. SUBJECTS: A complete data set of sociodemographic information, anthropometric measurements and blood pressure readings, as well as a psychological health test and a medical questionnaire, were obtained from 231 of the 431 first-year female students who attended the university orientation programme. Only students with a complete data set were included in the sample. RESULTS: Eighteen per cent of students were overweight (BMI 25-29.9), 6.5% were obese (BMI > or = 30), and 26.8% were underweight. Mean blood pressure, BMI, WHR and WC increased significantly with age and were highest among the > or = 24-year-olds. Only 1.6% of students had elevated blood pressure, 1.0% smoked and 4.4% took snuff. BMI, WC and WHR were positively correlated with blood pressure and age. Few students had dyslipidaemia (3.8% cholesterol > 5.2 mmol/l). However 14.5% were anaemic (Hb < 11.5 g/dl) and 24.6% had microcytosis (< 80 fl). Nearly one-fifth of students (17.7%) were classified as being moderately to severely depressed. CONCLUSIONS: Black female students younger than 24 years exhibited few risk factors associated with chronic diseases of lifestyle. However in older women (> or = 24 years) there were significant increases in BMI, WHR, WC and blood pressure. A large number of students of all ages exhibited moderate to severe depression and anaemia was prevalent.