SA cardiovascular laboratories mining diverse, yet relevant research topics

This issue of SA Heart reports on some ongoing work performed in South Africa that engages with more fundamental issues of the mechanisms of cardiovascular disease. This special edition of the journal highlights some of the high quality, internationally competitive, clinically relevant, basic cardiovascular science presently being undertaken by a number of groups around the country in this regard. Although the topics covered in the present issue are diverse, all have an important clinical context and in this editorial we will attempt to describe this context

Hypertension in Africa: Redressing the burden of cardiovascular disease using cost-effective nonpharmacological approaches

Hypertension may affect approximately one fifth or more of all adult South Africans. Despite the considerable evidence derived from economically developed countries to indicate the extent to which hypertension contributes to cardiovascular disease (CVD), it is only more recently that data has emerged from the African continent to support a contention that hypertension is the principal risk factor for CVD in African populations and that CVD accounts for a major proportion of deaths in the elderly and in younger adults in rural Africa. Active engagement in the harsh realities of managing this complex clinical trait should therefore be foremost on the minds of the healthcare sector in Africa. In this regard there are unique challenges. In the present personal review we synthesise the evidence for or against the view that at a public health level, the answer to significantly reducing the burden of CVD produced by hypertension in African populations, may lie in something as simple as generating a healthier lifestyle. In this regard, we place recent evidence obtained from South African studies of the importance of modifiable cardiovascular risk factors related to hypertension, including salt intake and obesity, in the context of previously published evidence. We highlight the very recent and the first substantive evidence derived from an African community to show that salt intake indeed contributes to a significant portion of blood pressure (BP) variability in African populations, but this effect may be hidden because the impact is largely on central (aortic) rather than brachial BP. We also discuss the increasing evidence to show that in African populations, the adverse effects of the epidemic of obesity that faces emerging communities is likely to account for a substantial proportion of cardiovascular risk not through marked effects on brachial BP, but through indirect effects by promoting the adverse effects of BP on the heart. In the present review we therefore argue that despite limited absolute effects of salt intake and obesity on brachial BP, a marked benefit could be gained by the BP effects of salt restriction and body weight reduction in African communities

Non-Linear Behavior of Protein and Tannin in Wine Produced by Cofermentation of an Interspecific Hybrid (Vitis spp.) and Vinifera Cultivar

Wines produced from red interspecific hybrid grape cultivars (Vitis spp.) typically have lower tannin than wines produced from vinifera cultivars, which can be attributed to the lower concentration of tannins and higher concentration of tannin binding proteins of interspecific cultivars. Tannin in wines produced from hybrid cultivars could potentially be increased by blending hybrids with vinifera. We hypothesized that blending of grapes prior to fermentation (cofermentation) should result in final wine tannin concentrations lower than wine tannin concentrations predicted from the individual components due to protein-tannin binding, but that this effect should be absent from monovarietal wines blended post-fermentation. To evaluate this hypothesis, over a two-year study, a high tannin V. vinifera cultivar (Cabernet Sauvignon) was blended with an interspecific hybrid (Marquette) at different ratios either before (cofermentation) or after fermentation. The tannin and protein concentrations of the wines were measured by methyl cellulose precipitation assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. Tannin and protein concentrations in blended wines were compared to values predicted from the linear combination of the two monovarietal wines. Co-fermented blends with a high proportion of Marquette had up to 25% lower tannin than predicted, but for most cofermentations and post-fermentation blends observed and predicted tannin concentrations did not differ. However, protein concentrations for many of the blends – especially from cofermentation - were lower than the predicted values, in some cases \u3e50%. Loss of protein due to adsorption to tannin was well modeled by a Freundlich absorption isotherm

Rheumatoid arthritis is associated with reduced adiposity but not with unfavorable major cardiovascular risk factor profiles and enhanced carotid atherosclerosis in black Africans from a developing population: a cross-sectional study

INTRODUCTION: Rheumatoid arthritis (RA) is characterized by inflamed joint-derived cytokine-mediated high-grade systemic inflammation that enhances cardiovascular metabolic risk and disease in developed populations. We investigated the potential impact of RA on cardiovascular risk factors including systemic inflammation and atherosclerosis, and their relationships in black Africans from a developing population. METHODS: We evaluated demographic features, adiposity indices, major traditional cardiovascular risk factors, circulating C-reactive protein and interleukin-6 concentrations and ultrasound determined carotid intima-media thickness (cIMT) in 274 black Africans; 115 had established RA. Data were analyzed in confounder-adjusted mixed regression models. RESULTS: The body mass index and waist-height ratio were lower in RA compared to non-RA subjects (29.2 (6.6) versus 33.7 (8.0), P < 0.0001 and 0.58 (0.09) versus 0.62 (0.1), P = 0.0003, respectively). Dyslipidemia was less prevalent in patients with RA (odds ratio (OR) (95% confidence interval (CI) = 0.54 (0.30 to1.00)); this disparity was no longer significant after further adjustment for reduced adiposity and chloroquine use. RA was also not associated with hypertension, current smoking and diabetes. The number of major traditional risk factors did not differ by RA status (1.1 (0.8) versus 1.2 (0.9), P = 0.7). Circulating C-reactive protein concentrations were similar and serum interleukin-6 concentrations reduced in RA (7.2 (3.1) versus 6.7 (3.1) mg/l, P = 0.7 and 3.9 (1.9) versus 6.3 (1.9) pg/ml, P < 0.0001, respectively). The cIMT was 0.700 (0.085) and 0.701 (0.111) mm in RA and non-RA subjects, respectively (P = 0.7). RA disease activity and severity parameters were consistently unrelated to systemic inflammation, despite the presence of clinically active disease in 82.6% of patients. In all participants, adiposity indices, smoking and converting angiotensin inhibitor non-use were associated with increased systemic inflammation, which related to more atherogenic lipid profiles, and circulating low density lipoprotein concentrations were associated with cIMT (partial R = 0.153, P = 0.032); RA did not impact on these relationships (interaction P ≥0.1). CONCLUSIONS: Among black Africans, patients with established RA experience reduced overall and abdominal adiposity but no enhanced major traditional risk factor and atherosclerosis burden. This study further suggests that an absent interleukin-6 release by inflamed RA joints into the circulation may account for this unaltered cardiovascular disease risk

Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats

Although obesity is an independent risk factor for heart failure and even mild-to-moderate forms of obesity are associated with myocardial systolic dysfunction the mechanisms of the myocardial dysfunction have not been identifi ed. We assessed whether dietary-induced obesity is associated with an increased sensitivity of the myocardium to ß-adrenergic-induced cardiomyocyte apoptosis or fibrosis. To induce obesity, rats were fed a diet that promotes an increased caloric intake. Adrenergic-induced cardiomyocyte apoptosis was determined by injecting rats for 5 days with isoproterenol (0.01 mg/kg/day for 3 days and 0.02 mg/kg/day for 2 days) and then studying the degree of cardiomyocyte damage using a TUNEL assay and assessing the pathological score. Five months of feeding rats a diet that promoted the development of an increased body weight (Control=481±4.3 g, Diet=550±7.8 g, p‹0.001) and visceral fat content (Control=19.6±0.8 g, Diet=33.0±1.2 g, p‹0.0001), did not alter baseline cardiomyocyte apoptosis. However, 5 days of ß-adrenergic activation resulted in an enhanced cardiomyocyte apoptosis in rats receiving the experimental diet as compared to rats receiving a normal diet (p‹0.01). No changes in the myocardial pathological score (fibrosis) were noted. The enhanced adrenergic-induced cardiomyocyte apoptosis in obese rats could not be explained by dietary-induced increases in baseline left ventricular internal diameters, decreases in systolic function (endocardial or midwall fractional shortening) or differences in the response of the heart to adrenergic-induced increases in inotropic or chronotropic function. In conclusion, the present study suggests that obesity may contribute to myocardial dysfunction by increasing the sensitivity of the myocardium to adrenergic-induced cardiomyocyte damage

Habitat diversity and structure regulate British bird richness: implications of non-linear relationships for conservation

Spatial environmental heterogeneity (EH) is an important factor determining species richness among many taxa across spatial scales. Increased EH may support higher diversity mainly by providing a higher number of ecological niches. However, the shapes of the EH-diversity relationships and their influence on diversity measures at landscape scales are poorly understood. We used random forests regression models to assess the relationships between different components of EH and bird species richness across Great Britain. Bird data were obtained using BTO/JNCC/RSPB Breeding Bird Survey methods across 335 UK Countryside Survey (CS) 1-km squares in 2000. Data on components of EH, including; vegetation, habitat diversity, and habitat structure were collected in associated field surveys. Using the results of our EH component-bird richness models, we applied the case of the likely decline of the ash tree, a species of conservation concern and a key component of British landscape complexity, to create predictive scenarios of future bird richness. We found that EH components had a strong positive effect on bird richness and identified six key components that explained over 70% of variance in bird richness. Bird richness responses were strongly dependent on the specific EH components and were generally non-linear, especially for habitat structural variables, such as lines of trees and hedges. Our predictive scenarios showed a decrease in bird species richness only for simulated ash tree decreases within the habitat structural variables of over 90%, and only for areas where this tree species was a particularly abundant component of the landscape. Our findings, showing that bird richness responses differ for EH components, and that non-linear responses are common, could help the ‘design’ of landscapes that enhance bird diversity. In particular, our study indicates that, in some cases, increasing the occurrence of key structural components of habitat (such as ensuring a minimum of 700 m of managed hedges or a minimum of 70 individual trees per km square), could have disproportionally positive impacts on bird richness

The relationship between the nitric oxide synthase gene and the risk of hypertension defi ned according to ambulatory blood pressures

Although nitric oxide (NO) plays an important role in blood pressure (BP) control, whether variation of genes involved in regulating the synthesis of NO infl uences BP is uncertain. As the heritability of BP is stronger for ambulatory than it is for conventional BP, we assessed the independent association of the well described functional exon 7 Glu298Asp variant of the eNOS gene with the presence of hypertension in 511 randomly selected normotensive control participants and 503 hypertensives with a diagnosis of hypertension confi rmed with 24-hour ambulatory BP profiles whilst off therapy. We also assessed the relationship between eNOS genotype and 24 hour ambulatory BP. Comparisons of genotype and allele frequencies indicated a lack of association of the exon 7 Glu298Asp gene variant with hypertension (Odds ratio of genotype predicting the presence of hypertension=0.97, confidence interval=0.70-1.30, p=0.92). However, patients with the Glu/Glu genotype of the Glu298Asp variant (n=424) had increased 24-hour systolic and diastolic blood pressures (152±1/97±1 mm Hg) in comparison to patients heterozygous for the Glu298Asp variant or homozygous for the 298Asp allele (n=79) (145±1/94±1 mm Hg, p‹0.005 for systolic BP and p‹0.001 for diastolic BP after multiple adjustments including age, gender, body mass index and the presence of diabetes mellitus). Differences in systolic and diastolic BP between genotype groups were noted during the day as well as at night. The association of eNOS genotype with ambulatory BP translated into an increased risk of more severe grades of hypertension in patients with the Glu/Glu genotype (grade II and III vs. grade I, Odds ratio=2.20, confidence interval=1.34-3.59, p‹0.0002). In conclusion, a functional gene variant (Glu298Asp) at the eNOS locus contributes ~1.4-2.5% to the variation in ambulatory blood pressure within hypertensives, but is not associated with the presence of hypertension in patients in whom the diagnosis has been confirmed by 24-hour ambulatory BP values. The relationship between eNOS genotype and 24-hour ambulatory BP and the severity of hypertension warrants further study

IJTC2007-44218 Studies on ZDDP anti-wear films formed under the different conditions by XANES spectroscopy, atomic force microscopy and 31P NMR

ABSTRACT Antiwear (AW) films, generated from a mineral base oil containing zinc dialkyl dithiophosphate (ZDDP) additive, were extensively studied. These films were formed at various conditions such as different temperatures, various loads and rubbing times. The surface morphology of these films was investigated using atomic force microscopy (AFM) and the surface roughness of these films has been calculated from the images. X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of these films. The intensity of phosphorus K-edge was also used to monitor the thickness of these films. Phosphorus L-edge spectra show that these films have slightly variable chemical natures. 31P Nuclear magnetic resonance (31P NMR) was used to study the ZDDP components in the residue oils. The spectra show that the primary and secondary ZDDP decompose quite differently at the various conditions. Tribological characteristics of these AW films were probed by measuring the coefficients of friction and the wear scar width of the counter faces

2018 Establishing groundwater Nitrate / Nitrite levels In Hamilton, Montana & local areaMarch

We propose to collect emergent groundwater around Hamilton, using standardized collection methods that include quality and control samples with analysis performed at a certified drinking water testing laboratory (Energy Labs). Nitrate background in natural groundwater systems should contain less that\u27s 1 mg/L nitrates (U.S. Geological Survey) but in our aquifer, nitrates/nitrites should be less than 0.25 mg/L based on previous sampling. We will map the locations of the samples and use local hydrology data to help determine the source and flow direction of the groundwater. Routine testing and reporting of groundwater quality in our community will help protect our health and the economy of our river. Groundwater in sand and gravel aquifers from shallow wells supplies all the Hamilton area drinking water. The aquifers receive recharge from streams and ditches flowing in from he sides of the valley and the shallow aquifers discharge to the Bitterroot River and to ditches that flow past the West and north edge of Hamilton. we plan to collect about a dozen samples in an arc around the down gradient edge of Hamilton from these groundwater discharges. Nitrates are tasteless and odorless, and are often the first sign of deterioration of groundwater quality. Nitrates are a health threat because they can cause blue baby syndrome and may function as initiators of human carcinogenesis. Nitrates are also an environmental threat because they cause eutrophication damage to surface water aquatic environments in the Bitterroot River. High densities of private septic systems, and large acreages that receive fertilizer or that support farm animals are located up gradient to the south and eats of Hamilton. these are probable sources of pollution to shallow groundwater