Diagnostic performance of dobutamine stress echocardiography: A South African experience.

BACKGROUND: Dobutamine stress echocardiography (DSE) is a well-established modality for the diagnosis of coronary artery disease, but there are no reported diagnostic data in southern Africa. Objectives. To compare the safety, sensitivity and specificity of a South African (SA) DSE programme with larger, international series. Methods. All patients undergoing DSE from 2019 to 2021 at a single SA centre were included. A new wall motion abnormality (≥2 segments) signified inducible ischaemia. Results. A total of 106 patients (mean (standard deviation) age 61 (11) years, 68% male) were analysed. Six patients (6%) experienced chest pain during DSE and 4 (4%) developed an atrial arrhythmia. The sensitivity and specificity for epicardial coronary stenosis were 77% and 74%, respectively, changing to 82% and 72% when excluding those who had previous coronary artery bypass surgery. Conclusion. The sensitivity, specificity and safety of an SA DSE programme were comparable to international series. A DSE programme is feasible in a resource-constrained environment.

Qualitative and quantitative detection of SARS-CoV-2 RNA in untreated wastewater in Western Cape Province, South Africa.

Recent studies have shown that the detection of SARS-CoV-2 genetic material in wastewater may provide the basis for a surveillance system to track the environmental dissemination of this virus in communities. An effective wastewater-based epidemiology (WBE) system may prove critical in South Africa (SA), where health systems infrastructure, testing capacity, personal protective equipment and human resource capacity are constrained. In this proof-of-concept study, we investigated the potential of SARS-CoV-2 RNA surveillance in untreated wastewater as the basis for a system to monitor COVID-19 prevalence in the population, an early warning system for increased transmission, and a monitoring system to assess the effectiveness of interventions. The laboratory confirmed the presence (qualitative analysis) and determined the RNA copy number of SARS-CoV-2 viral RNA by reverse transcription polymerase chain reaction (quantitative) analysis from 24-hour composite samples collected on 18 June 2020 from five wastewater treatment plants in Western Cape Province, SA. The study has shown that a WBE system for monitoring the status and trends of COVID-19 mass infection in SA is viable, and its development and implementation may facilitate the rapid identification of hotspots for evidence-informed interventions.

Infective endocarditis in patients after percutaneous pulmonary valve implantation with the stent-mounted bovine jugular vein valve: Clinical experience and evaluation of the modified Duke criteria.

AIMS: Percutaneous pulmonary valve implantation (PPVI) has proven good hemodynamic results. As infective endocarditis (IE) remains a potential complication with limited available clinical data, we reviewed our patient records to improve future strategies of IE prevention, diagnosis and treatment. METHODS: Medical records of all patients diagnosed with Melody® valve IE according to the modified Duke criteria were retrospectively analyzed in three Belgian tertiary centers. RESULTS: 23 IE episodes in 22 out of 240 patients were identified (incidence 2.4% / patient year) with a clear male predominance (86%). Median age at IE was 17.9 years (range 8.2-45.9 years) and median time from PPVI to IE was 2.4 years (range 0.7-8 years). Streptococcal species caused 10 infections (43%), followed by Staphylococcus aureus (n = 5, 22%). In 13/23 IE episodes a possible entry-point was identified (57%). IE was classified as definite in 15 (65%) and as possible in 8 (35%) cases due to limitations of imaging. Echocardiography visualized vegetations in only 10 patients. PET-CT showed positive FDG signals in 5/7 patients (71%) and intracardiac echocardiography a vegetation in 1/1 patient (100%). Eleven cases (48%) had a hemodynamically relevant pulmonary stenosis at IE presentation. Nine early and 6 late percutaneous or surgical re-interventions were performed. No IE related deaths occurred. CONCLUSIONS: IE after Melody® valve PPVI is associated with a relevant need of re-interventions. Communication to patients and physicians about risk factors is essential in prevention. The modified Duke criteria underperformed in diagnosing definite IE, but inclusion of new imaging modalities might improve diagnostic performance.

Aspalathin, a C-glucosyl dihydrochalcone from rooibos improves the hypoglycemic potential of metformin in type 2 diabetic (db/db) mice.

Metformin is the first line therapy of type 2 diabetics, but continued reduction of their life expectancy warrants further investigation into alternative treatment strategies. This study reports on the combinational use of metformin with aspalathin, a C-glucosyl dihydrochalcone with known glucose lowering and antioxidant properties, as an effective hypoglycemic therapy in a type 2 diabetic (db/db) mouse model. When tested as a monotherapy, a low dose of aspalathin (13 mg/kg) showed no effect, while a high dose (130 mg/kg) has already displayed a better potential than metformin in protecting against diabetes associated symptoms in db/db mice. Thus, it remains of interest to determine whether this dihydrochalcone can improve the efficacy of metformin. The results showed that this combination therapy was more effective than the use of metformin as a monotherapy in ameliorating diabetes associated symptoms, including abnormal raised fasting plasma glucose levels, impaired glucose tolerance, as well as excessively increased body weights and fat content. The treated mice also had reduced food and water consumption when compared to untreated controls, with a pronounced effect evident in the last week of treatment. Therefore, this study supports further investigations into the ameliorative effect of combination therapy of metformin and aspalathin against diabetes associated symptoms.

Polyphenols, autophagy and doxorubicin-induced cardiotoxicity.

Doxorubicin is a highly effective, first line chemotherapeutic agent used in the management of hematological and solid tumors. The effective use of doxorubicin in cancer therapy has been severely limited owing to its well-documented cardiotoxic side effect. Oxidative stress, lipid peroxidation, apoptosis as well as dysregulation of autophagy, has been implicated as a major contributor associated with doxorubicin-induced cardiotoxicity. Increased oxidative stress and lipid peroxidation are known to enhance the production of reactive oxygen species, while autophagy has been reported to protect the cell from stress stimuli or, alternatively, contribute to cell death. Nonetheless, to date, no single chemical synthesized drug is available to prevent the harmful action of doxorubicin without reducing its anti-cancer efficacy. Therefore, the search for an effective and safe antagonist of doxorubicin-induced cardiotoxicity remains a challenge. In recent years, there has been much interest in the role plant-derived polyphenols play in the regulation of oxidative stress and autophagy. Therefore, the present review renders a concise overview of the mechanism associated with doxorubicin-induced cardiotoxicity as well as giving insight into the role plant-derived phytochemical play as a possible adjunctive therapy against the development of doxorubicin-induced cardiotoxicity.

MicroRNA Expression Varies according to Glucose Tolerance, Measurement Platform, and Biological Source.

Dysregulated microRNA (miRNA) expression is observed during type 2 diabetes (T2D), although the consistency of miRNA expression across measurement platform and biological source is uncertain. Here we report miRNA profiling in the whole blood and serum of South African women with different levels of glucose tolerance, using next generation sequencing (NGS) and quantitative real time PCR (qRT-PCR). Whole blood-derived miRNAs from women with newly diagnosed T2D (n = 4), impaired glucose tolerance (IGT) (n = 4), and normal glucose tolerance (NGT) (n = 4) were subjected to NGS, whereafter transcript levels of selected miRNAs were quantified in the whole blood and serum of these women using qRT-PCR. Of the five significantly differentially expressed miRNAs identified by NGS, only the directional increase of miR-27b in women with IGT compared to NGT was confirmed in whole blood and serum, using qRT-PCR. Functional enrichment of miR-27b gene targets identified biological pathways associated with glucose transport and insulin regulation. In conclusion, this study showed poor correlation in miRNA expression profiled using NGS and qRT-PCR and in whole blood and serum. The consistent increased expression of miR-27b in women with IGT compared to NGT across measurement platform and biological source holds potential as a biomarker for risk stratification in our population.

Solubility of Carbon Dioxide in Secondary Butyl Alcohol at High Pressures: Experimental and Modeling with CPA.

Mixtures of carbon dioxide and secondary butyl alcohol at high pressures are interesting for a range of industrial applications. Therefore, it is important to have trustworthy experimental data on the high-pressure phase behavior of this mixture over a wide range of temperatures. In addition, an accurate thermodynamic model is necessary for the optimal design and operation of processes. In this study, bubble points of binary mixtures of CO2 + secondary butyl alcohol were measured using a synthetic method. Measurements covered a CO2 molar concentration range of (0.10-0.57) % and temperatures from (293 to 370) K, with pressures reaching up to 11 MPa. The experimental data were modelled by the cubic plus association (CPA) equation of state (EoS), as well as the more simple Soave-Redlich-Kwong (SRK) EoS. Predictive and correlative modes were considered for both models. In the predictive mode, the CPA performs better than the SRK because it also considers associations.

Risperidone-associated adverse drug reactions and CYP2D6 polymorphisms in a South African cohort.

BACKGROUND: Contradictory information exists regarding the influence of CYP2D6 polymorphisms on adverse drug reactions (ADRs) (extrapyramidal symptoms (EPS) and weight gain) related to risperidone treatment. This prompted us to evaluate the influence of CYP2D6 genetic variation in a cohort of South African patients who presented with marked movement disorders and/or weight gain while on risperidone treatment. METHODS: Patients who were experiencing marked risperidone ADRs were recruited from Weskoppies Public Psychiatric Hospital. As poor or intermediate metabolism was expected, comprehensive CYP2D6 sequence variations were evaluated using XL-PCR + Sequencing. RESULTS: No statistically significant association was found between CYP2D6 poor metabolism and risperidone ADRs. An inverse relationship between EPS and weight gain was however identified. A novel CYP2D6 allele was identified which is unlikely to affect metabolism based on in silico evaluation. CONCLUSION: CYP2D6 variation appeared not to be a good pharmacogenetic marker for predicting risperidone-related ADRs in this naturalistic South African cohort. Evaluation of a larger cohort would be needed to confirm these observations, including an examination of the role of potential intermediaries between the hypothesised genetic and clinical phenotypes.

Decreased global DNA methylation in the white blood cells of high fat diet fed vervet monkeys (Chlorocebus aethiops)

Epigenetic mechanisms are associated with the development of many chronic diseases and due to their reversible nature offer a unique window of opportunity to reverse the disease phenotype. This study investigated whether global DNA methylation correlates with dysglycemia in the vervet monkey (Chlorocebus aethiops). Diet-induced changes in DNA methylation were observed where global DNA methylation was twofold lower in monkeys fed a high fat diet (n = 10) compared to monkeys fed a standard diet (n = 15). An inverse correlation was observed between DNA methylation, blood glucose concentrations, bodyweight, and age, although the association was not statistically significant. Consumption of a high fat diet is associated with the development of metabolic disease; thus, these results suggest the use of global DNA methylation as a biomarker to assess the risk for metabolic disease. Moreover, this study provides further support for the use of the vervet monkey as a model system to study metabolic diseases such as type 2 diabetes. Integration of altered DNA methylation profiles into predictive models could facilitate risk stratification and enable intervention strategies to inhibit disease progression. Such interventions could include lifestyle modifications, for example, the increased consumption of functional foods with the capacity to modulate DNA methylation, thus potentially reversing the disease phenotype and preventing disease (AU)

Decreased global DNA methylation in the white blood cells of high fat diet fed vervet monkeys (Chlorocebus aethiops).

Epigenetic mechanisms are associated with the development of many chronic diseases and due to their reversible nature offer a unique window of opportunity to reverse the disease phenotype. This study investigated whether global DNA methylation correlates with dysglycemia in the vervet monkey (Chlorocebus aethiops). Diet-induced changes in DNA methylation were observed where global DNA methylation was twofold lower in monkeys fed a high fat diet (n = 10) compared to monkeys fed a standard diet (n = 15). An inverse correlation was observed between DNA methylation, blood glucose concentrations, bodyweight, and age, although the association was not statistically significant. Consumption of a high fat diet is associated with the development of metabolic disease; thus, these results suggest the use of global DNA methylation as a biomarker to assess the risk for metabolic disease. Moreover, this study provides further support for the use of the vervet monkey as a model system to study metabolic diseases such as type 2 diabetes. Integration of altered DNA methylation profiles into predictive models could facilitate risk stratification and enable intervention strategies to inhibit disease progression. Such interventions could include lifestyle modifications, for example, the increased consumption of functional foods with the capacity to modulate DNA methylation, thus potentially reversing the disease phenotype and preventing disease.

Blood-borne infections in healthcare workers in South Africa.

The risks associated with infection of healthcare workers and students with blood-borne pathogens, specifically HIV, hepatitis B virus and hepatitis C virus, are often neglected. South Africa (SA) currently has no official policies or guidelines in place for the prevention and management of these infections. This article reviews the available data and international guidelines with regard to infected healthcare practitioners and makes minimum recommendations for the SA setting.

Prevalence and factors associated with tuberculosis treatment outcome among hazardous or harmful alcohol users in public primary health care in South Africa.

BACKGROUND: Tuberculosis (TB) remains a chronic infectious disease with high morbidity and mortality. OBJECTIVE: The aim of this study was to assess the prevalence and associated factors of tuberculosis treatment failure, death and default among hazardous or harmful alcohol users. METHOD: We conducted a prospective study with TB patients in 40 public health clinics in three districts in South Africa. All consecutively new tuberculosis and retreatment patients presenting at the 40 primary health care facilities with hazardous or harmful alcohol use were included in this study. Logistic regression was used to assess determinants of TB treatment failure, death and default. RESULTS: The findings of our study showed that 70% of TB patients were either cured or had completed their TB treatment by the end of 6 months. In multivariate analysis participants living in a shack or traditional housing (Odds Ratio=OR: 0.63, Confidence Interval=CI: 0.45-0.89), being a TB retreatment patient (OR: 1.61, CI: 1.15-2.26) and residing in the eThekwini district (OR: 1.82, CI: 1.27-2.58) were significant predictors of treatment failure, death and default. CONCLUSION: A high rate of treatment failure, death and default were found in the TB patients. Several factors were identified that can guide interventions for the prevention of treatment failure, death and default.

The cardioprotective effect of an aqueous extract of fermented rooibos (Aspalathus linearis) on cultured cardiomyocytes derived from diabetic rats.

Diabetic cardiomyopathy (DCM) is a disorder of the heart muscle that contributes to cardiovascular deaths in the diabetic population. Excessive generation of free radicals has been directly implicated in the pathogenesis of DCM. The use of antioxidants, through dietary supplementation, to combat increased cellular oxidative stress has gained popularity worldwide. Aspalathus linearis (rooibos) is a popular herbal tea that contains a novel antioxidant, aspalathin. Literature has reported on the antidiabetic, anti-inflammatory and free radical scavenging effects of rooibos. However, its protective effect against DCM has not been established. Therefore, this study investigated whether chronic exposure to an aqueous extract of fermented rooibos (FRE) has an ex vivo cardioprotective effect on hearts obtained from streptozotocin (STZ) induced diabetic rats. Adult Wistar rats were injected with 40 mg/kg of STZ. Two weeks after STZ injection, cardiomyocytes were isolated and cultured. Cultured cardiomyocytes were treated with FRE (1 and 10 µg/ml), vitamin E (50 µg/ml), and n-acetyl cysteine (1mM) for 6h, before exposure to either hydrogen peroxide (H2O2) or an ischemic solution. Cardiomyocytes exposed to H2O2 or an ischemic solution showed a decrease in metabolic activity and glutathione content with a concomitant increase in apoptosis and intracellular reactive oxygen species. Pretreatment with FRE was able to combat these effects and the observed amelioration was better than the known antioxidant vitamin E. This study provides evidence that an aqueous extract of fermented rooibos protects cardiomyocytes, derived from diabetic rats, against experimentally induced oxidative stress and ischemia.

Amelioration of palmitate-induced insulin resistance in C2C12 muscle cells by rooibos (Aspalathus linearis).

Increased levels of free fatty acids (FFAs), specifically saturated free fatty acids such as palmitate are associated with insulin resistance of muscle, fat and liver. Skeletal muscle, responsible for up to 80% of the glucose disposal from the peripheral circulation, is particularly vulnerable to increased levels of saturated FFAs. Rooibos (Aspalathus linearis) and its unique dihydrochalcone C-glucoside, aspalathin, shown to reduce hyperglycemia in diabetic rats, could play a role in preventing or ameliorating the development of insulin resistance. This study aims to establish whether rooibos can ameliorate experimentally-induced insulin-resistance in C2C12 skeletal muscle cells. Palmitate-induced insulin resistant C2C12 cells were treated with an aspalathin-enriched green (unfermented) rooibos extract (GRE), previously shown for its blood glucose lowering effect in vitro and in vivo or an aqueous extract of fermented rooibos (FRE). Glucose uptake and mitochondrial activity were measured using 2-deoxy-[³H]-D-glucose, MTT and ATP assays, respectively. Expression of proteins relevant to glucose metabolism was analysed by Western blot. GRE contained higher levels of all compounds, except the enolic phenylpyruvic acid-2-O-glucoside and luteolin-7-O-glucoside. Both rooibos extracts increased glucose uptake, mitochondrial activity and ATP production. Compared to FRE, GRE was more effective at increasing glucose uptake and ATP production. At a mechanistic level both extracts down-regulated PKC θ activation, which is associated with palmitate-induced insulin resistance. Furthermore, the extracts increased activation of key regulatory proteins (AKT and AMPK) involved in insulin-dependent and non-insulin regulated signalling pathways. Protein levels of the glucose transporter (GLUT4) involved in glucose transport via these two pathways were also increased. This in vitro study therefore confirms that rooibos can ameliorate palmitate-induced insulin resistance in C2C12 skeletal muscle cells. Inhibition of PKC θ activation and increased activation of AMPK and AKT offer a plausible mechanistic explanation for this ameliorative effect.

"It's important to take your medication everyday okay?" An evaluation of counselling by lay counsellors for ARV adherence support in the Western Cape, South Africa.

There is growing interest in standard care programmes for antiretroviral (ARV) adherence support. In South Africa, individual counselling following ARV initiation is a main strategy for supporting adherence in the public sector. Egan's client-centred "Skilled Helper" counselling model is the predominant model used in HIV counselling in this context. This study evaluated counselling delivered by lay ARV adherence counsellors in Cape Town in terms of adherence to Egan's model. Thirty-eight transcripts of counselling sessions with non-adherent patients were analysed based on the methods of content analysis. These sessions were conducted by 30 counsellors. Generally counsellors' practice adhered neither to Egan's model nor a client-centred approach. Inconsistent with evidence-based approaches to counselling for ARV adherence support, counsellors mainly used information-giving and advice as strategies for addressing clients' non-adherence. Recommendations for improving practice are made. The question as to how appropriate strategies from developed countries are for this setting is also raised.

Acute assessment of an aspalathin-enriched green rooibos (Aspalathus linearis) extract with hypoglycemic potential.

Rooibos, an endemic South African plant, known for its use as herbal tea, has potential as an antidiabetic herbal product, following recent demonstration of the glucose lowering effect of its major flavonoid, the dihydrochalcone C-glucoside aspalathin. The purpose of this study was to confirm antidiabetic activity for rooibos extract high in aspalathin content. An extract (SB1) was selected after screening for high aspalathin content and α-glucosidase inhibition activity. On-line HPLC-biochemical detection confirmed α-glucosidase inhibitory activity for aspalathin. In vitro the extract induced a dose response increase in glucose uptake (5 × 10⁻5 to 5 µg/ml) on C2C12 myotubules. Aspalathin was effective at 1, 10 and 100 µM, while rutin was effective at 100 µM. In the Chang cells only the extract was effective. In vivo the extract sustained a glucose lowering effect comparable to metformin over a 6h period after administration (25mg/kg body weight (BW)) to STZ-induced diabetic rats. In an oral glucose tolerance test the extract (30 mg/kg BW) was more effective than vildagliptin (10mg/kg BW), a dipeptidyl peptidase-4 inhibitor. An aspalathin-rutin mixture (1:1; m/m) dosed at 1.4 mg/kg BW, but not the single compounds separately, reduced blood glucose concentrations of STZ-induced diabetic rats over a 6h monitoring period. The improved hypoglycemic activity of the aspalathin-rutin mixture and the extract illustrated synergistic interactions of polyphenols in complex mixtures.

An in vitro assessment of the effect of Athrixia phylicoides DC. aqueous extract on glucose metabolism.

Athrixia phylicoides DC. is an aromatic shrub indigenous to the eastern parts of Southern Africa. Indigenous communities brew "bush tea" from dried twigs and leaves of A. phylicoides, which is consumed as a beverage and used for its medicinal properties. Plant polyphenols have been shown to be beneficial to Type 2 diabetes mellitus (T2D) and obesity. Aqueous extracts of the plant have been shown to be rich in polyphenols, in particular phenolic acids, which may enhance glucose uptake and metabolism. The aim of this study was to determine the phenolic composition of a hot water A. phylicoides extract and assess its in vitro effect on cellular glucose utilisation. The most abundant phenolic compounds in the extract were 6-hydroxyluteolin-7-O-glucoside, chlorogenic acid, protocatechuic acid, a di-caffeoylquinic acid and a methoxy-flavonol derivative. The extract increased glucose uptake in C2C12, Chang and 3T3-L1 cells, respectively. Intracellular glucose was utilised by both oxidation (C2C12 myocytes and Chang cells; p < 0.01 and p < 0.05, respectively) and by increased glycogen storage (Chang cells; p < 0.05). No cytotoxicity was observed in Chang cells at the concentrations tested. The effects of the extract were not dose-dependent. A. phylicoides aqueous extract stimulated in vitro glucose uptake and metabolism, suggesting that consumption of this phenolic-rich extract could potentially ameliorate metabolic disorders related to obesity and T2D.

Predictors of non-uptake of human immunodeficiency virus testing by tuberculosis public primary patients in three districts, South Africa.

BACKGROUND: The acceptance of HIV testing among patients with tuberculosis (TB) is low in South Africa. The aim of this study was to assess the prevalence, associated factors and reasons of non-uptake of human immunodeficiency virus (HIV) testing by tuberculosis public primary care patients in three districts, South Africa. METHODS: In May-October 2011, this cross-sectional survey was conducted amongst 4726 TB patients across 42 primary health care facilities in three districts in South Africa. All new TB and new retreatment patients (N=4726) were consecutively interviewed within one month of anti-tuberculosis treatment. The outcome was self-reported HIV testing after TB diagnosis, validated using clinic registers. RESULTS: Almost one in ten (9.6%) of the 4726 participants had not undergone HIV testing, with the most often offered explanation being that they were not knowing where to get tested (21.3%), followed by believing not to have or at risk for HIV (24.3%), emotional concerns (not ready for test: 13.2%; afraid to get to know: 12.1%; concerns over confidentiality: 6.3%) and concerns about stigma (3.3%) and losing the job (2.0%). In multivariable analysis being male, severe psychological distress, having sex with someone HIV negative or unknown and frequency of sex without a condom were associated with not having been tested for HIV. CONCLUSIONS: The level of HIV testing among TB public primary care patients was suboptimal, as per policy all patients should be tested. The South African Department of Health should continue to scale-up HIV testing and other collaborative TB-HIV services at health facilities.

Behaviour change counselling for ARV adherence support within primary health care facilities in the Western Cape, South Africa.

Health care systems have been described as ideal settings for behaviour change counselling interventions. There is little research evaluating the feasibility of implementing such interventions in routine practice in primary care facilities. We implemented an intervention called Options for Health within routine adherence counselling practice in 20 antiretroviral facilities in Cape Town, South Africa. Lay counsellors were trained to use Options to help clients to optimise ARV adherence and reduce sexual risk behaviour. Counsellors delivered the intervention to 9% of eligible patients over 12 months. Interviews with counsellors revealed barriers to implementation including a lack of counselling space, time pressure and patient resistance to counselling. Counsellors felt that Options was not appropriate for use with all patients and adherence problems, and used parts of the intervention as it suited their needs. Findings revealed weaknesses in the current adherence counselling system that have implications for the feasibility of behaviour change counselling within this context.