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Biomedical subjects

H C Barnard

Publications and source records attributed to H C Barnard.

At least 19 recordsLinked to original sources
PubMed1999

Nutritional status of HIV-1 seropositive patients in the Free State Province of South Africa: anthropometric and dietary profile.

OBJECTIVE: To evaluate the nutritional intake and status of HIV-1 seropositive patients, as well as the relationship between malnutrition and disease stage. DESIGN: A cross-sectional study. SETTINGS: The Immunology Clinic at the Pelonomi Hospital in Bloemfontein, South Africa. SUBJECTS: Eighty-one HIV/AIDS patients in different stages of disease were recruited consecutively from January to May 1995. Eleven of these patients were followed in 1997. MAIN OUTCOME MEASURES: Anthropometric data including current weight, height, triceps skinfold thickness, mid-upper-arm circumference, body mass index and bone-free arm muscle area were collected. Nutrient intake was estimated using a diet history in combination with a standardised food frequency questionnaire. The patients were divided into 3 groups according to their CD4+ T cell counts. RESULTS: The men were leaner (BMI = 18.9) than the women (BMI = 22.7) and patients with a CD4+ T cell count < 200 (stage III) tended to have the lowest median values for all anthropometric measurements. More than half the patients had a low intake (< 67% of the recommended dietary allowances) of vitamin C, vitamin B6, vitamin D, vitamin A, calcium, iron and zinc. CONCLUSIONS: The results confirms that HIV/AIDS patients from this population are malnourished. There was, however, no association between disease stage and nutritional status. Nutritional supplementation of HIV/AIDS patients should be considered, as this might lead to improved immune function in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Nutritional status of HIV-1 seropositive patients in the Free State Province of South Africa--laboratory parameters.

OBJECTIVE: To evaluate the nutritional status of HIV-1 seropositive patients with regards to laboratory parameters; the correlation between nutrient intake and actual values of nutrients, as well as the relationship between malnutrition and disease progression. DESIGN: A cross sectional study. SETTING: The Immunology Clinic at the Pelonomi Hospital in Bloemfontein, South Africa. SUBJECTS: 90 HIV/AIDS patients in different stages of disease were recruited consecutively from January to May 1995. Sixteen patients were followed up in 1997. MAIN OUTCOME MEASURES: The patients were divided into three groups according to their CD4+ T-cell counts, and blood levels of protein, albumin, cholesterol, ferritin, vitamin B12, magnesium, and phosphorus, as well as several micronutrients including vitamin E, vitamin C, beta-carotene and retinol which were determined using standard methods. These values were compared with the normal reference values used in the laboratory, and we tried to correlate these parameters with disease stage, as well as recorded nutrient intake in a subgroup of 35 patients. RESULTS: Abnormal values for several parameters, including plasma-retinol and serum-protein were found, but no correlation between more advanced disease and micronutrient deficiencies could be demonstrated. CONCLUSIONS: HIV/AIDS patients from this population are deficient in several micronutrients, and for some patients this is mirrored by a low intake. Multivitamin/anti-oxidant supplementation of HIV/AIDS patients should be considered, as this could lead to improved immune function in these patients.

Adolescent↗
PubMed1998

Dietary iron concentration alters LDL oxidatively. The effect of antioxidants.

Low-density lipoprotein (LDL) cholesterol participates in the atherosclerotic process only after oxidative modification (o-LDL). Persons with elevated body iron concentrations are at higher risk of atherosclerosis. Iron in vitro is capable of oxidizing LDL, but it is unknown whether or not high dietary iron concentrations alter LDL in vivo. The aim of this study was, therefore, to investigate (i) whether dietary iron concentrations cause LDL-cholesterol oxidation and (ii) whether antioxidants can prevent such changes. Rats received diets differing only in iron concentration: 35 mg/kg, 150 mg/kg or 300 mg/kg diet. A LDL-VLDL particle was isolated and the following parameters measured: malondialdehyde and lipid hydroperoxide concentrations (as an indication for lipid peroxidation); alpha-tocopherol and retinol concentrations (as antioxidants); protein sulfhydryl and carbonyl concentrations (as an indication of protein modification); agarose gel electrophoresis and cholesterol/protein ratio. Dietary iron increased LDL-VLDL lipid peroxidation (malondialdehyde and lipid hydroperoxide concentrations), protein modification (sulfhydryl concentration), agarose migration distance and band width as well as cholesterol/protein ratio. Increased quantities of dietary iron led to a higher degree of oxidative change in LDL-VLDL. Lipid peroxidation, as well as protein modification, occurred, suggesting apoB changes. This was probably due to diminished antioxidant concentrations of alpha-tocopherol and beta-carotene. Antioxidant supplementation (alpha-tocopherol and beta-carotene), however, prevented all the above changes and could be helpful in the prevention of atherosclerosis.

Animals↗
PubMed1997

Influence of ferritin levels on LDL cholesterol concentration in women.

Various researchers have observed a higher risk for atherosclerosis when body iron concentration is elevated. The exact mechanism, however, is not known, but probably occurs catalytically via iron. Whether or not body iron concentration has an effect on plasma lipoproteins is also unknown. The aim of this study was to investigate whether or not ferritin concentration within the normal range correlate with LDL-cholesterol (an atherosclerotic risk factor), HDL-cholesterol, apoB, triglyceride and the mobility of LDL particles. Blood was drawn from healthy female volunteers and the above parameters measured. LDL-cholesterol, apoB and the electrophoretic mobility of LDL particles were elevated with increasing ferritin concentrations. Both modified or oxidized LDL and elevated LDL concentration are regarded as risks for atherosclerosis and ischemic heart disease, suggesting that higher body iron is important in this process.

Adolescent↗
PubMed1994

Effects of a low-insulin-response, energy-restricted diet on weight loss and plasma insulin concentrations in hyperinsulinemic obese females.

The effects of two low-energy diets on serum insulin concentrations and weight loss in obese hyperinsulinemic females were compared during a 12-wk period. The first diet (n = 15) was designed to evoke a low insulin response (ID), and the second (n = 15) was a conventionally balanced diet (ND). After a 12-wk washout period, seven and nine subjects who had been on the ID and ND, respectively, changed to the alternative diet for 12 wk. Variables studied were basal and 30- and 120-min concentrations of blood glucose, insulin, and C-peptide after an oral glucose load; body weight; and energy intake. Mean (+/- SD) weight was significantly reduced after ID and ND (9.35 +/- 2.49 and 7.41 +/- 4.23, respectively). The mean weight loss was more after ID. Fasting insulin concentrations decreased more after ID compared with ND (91.3 +/- 61.8 vs 21.0 +/- 71.5 pmol/L; P < 0.05). We conclude that ID significantly reduces serum insulin concentrations and weight in obese hyperinsulinemic females.

Adult↗
PubMed1994

Salicylate in the perfusate during ischemia/reperfusion prevented mitochondrial injury.

Salicylate is widely used as a stable trap for the highly reactive hydroxyl radical. The purpose of this study was to determine whether the addition of salicylate to hearts subjected to ischemia and reperfusion was able to prevent some injury. Salicylate was able to inhibit mitochondrial damage, and preserved ascorbate and alpha-tocopherol depletion due to ischemia/reperfusion in rat hearts. It did not prevent the elevation of low molecular weight iron. We conclude that salicylate functions as an antioxidant and afforded protection against ischemia and reperfusion.

Animals↗
PubMed1994

Both fish oil and olive oil lowered plasma fibrinogen in women with high baseline fibrinogen levels.

This double-blind, cross-over study with olive oil as placebo, examined the effect of a daily dosage of 6 g fish oil on cardiovascular risk markers of 20 healthy young volunteers (10 men, 10 women). Serum lipids and lipoproteins, and plasma coagulation and fibrinolytic enzymes, including fibrinogen concentrations and plasminogen activator inhibitor-1 (PAI-1) activity were measured at baseline and after 6-week supplementation of either fish or olive oil. The results showed that fish oil had an independent lowering effect on triglycerides and coagulation factors Vc and VIIc. Both fish and olive oil significantly raised PAI-1 levels and lowered plasma factor Xc and fibrinogen levels in the women, who had higher initial levels than the men. Mean fibrinogen levels of the women were lowered from 3.23 +/- 0.98 to 2.64 +/- 0.55 g/l and from 3.19 +/- 0.72 to 2.66 +/- 0.49 g/l by fish and olive oil respectively. This study raises the question whether a particular fatty acid or group of fatty acids, or another constituent of the oil such as vitamin E may be responsible for the fibrinogen lowering effect.

Administration, Oral↗
PubMed1992

Egg intake does not change plasma lipoprotein and coagulation profiles.

The effect of the intake of 3-14 eggs/wk on biochemical risk markers of coronary heart disease (CHD) was examined in 70 young men who followed a high-fat diet. The study consisted of a run-in phase during which all subjects ate 3 eggs/wk for 2 mo and an experimental phase during which a reference group continued eating 3 eggs/wk and two experimental groups ate either 7 or 14 eggs/wk for 5 mo. The mean coefficients of variation in total plasma cholesterol (5.4-7.4%) were similar in all three groups and were larger than the mean changes of 0.2-5.6% in plasma cholesterol from baseline to end in the experimental groups. Except for increased lecithin-cholesterol acyltransferase activities and total serum protein concentrations, no significant differences in lipoproteins or coagulation factors occurred between groups. It seems that egg intake in this range did not influence CHD risk markers in these subjects. Recommendations to lower risk should probably concentrate on a reduction in fat and not cholesterol intake.

Adolescent↗
PubMed1991

Epidemiological reference ranges for low-density lipoprotein cholesterol and apolipoprotein B for identification of increased risk of ischaemic heart disease.

Although there is widespread acceptance that total cholesterol (TC) value reference ranges should be based on epidemiological rather than statistical considerations, the epidemiological action limits for low-density lipoprotein cholesterol (LDL-C) are still incomplete and only statistical reference ranges for apolipoprotein B (Apo-B) levels are available. The combined use of epidemiological reference ranges for TC and incomplete or statistical reference ranges for LDL-C and Apo-B is illogical, since these parameters may fall into discordant risk categories that will hamper and complicate the management of hypercholesterolaemia. Based on a study of lipograms obtained from +/- 3,000 inhabitants of two industrialised Transvaal towns, the age-related epidemiological reference ranges for LDL-C and Apo-B were established. A comparison with published observational studies of other populations, in which comparable lipid, lipoprotein and apolipoprotein methodologies were used, reflected the severity of these lipid-related abnormalities in white South Africans, especially after the age of 30 years. In addition, the serum TC values found in this survey were not significantly different from those obtained 10 years ago.

Adolescent↗
PubMed1990

Biochemical reference values in elderly black subjects.

Biochemical reference values for the black age group of greater than or equal to 65 years were determined from the black urban population of the Orange Free State. Biochemical investigations performed were those included in the Sequential Multiple Analyser Computer profile because it includes the 20 most requested clinical chemistry investigations. Most of the reference values corresponded to values for the same age groups in the Western world. There was no age-related rise in the alkaline phosphatase values, which suggested absence of occult Paget's disease. Reference values for serum total protein and globulin were found to be higher than values derived from elderly white groups.

Age Factors↗
PubMed1990

The effect of desferal on rat heart mitochondrial function, iron content, and xanthine dehydrogenase/oxidase conversion during ischemia-reperfusion.

Cardiac mitochondrial function as measured by oxidative phosphorylation is impaired by ischemia; and, this deteriorates even further on reperfusion of the heart. Free oxygen radicals, especially the formation of hydroxyl radicals via the iron-catalyzed Haber-Weiss and Fenton reactions have been implicated in the reperfusion injury. In this study, the effect of desferrioxamine (desferal) in the perfusate on mitochondrial function of isolated rat hearts during different periods of normothermic ischemic cardiac arrest (NICA), and subsequent reperfusion was investigated. Mitochondrial functions measured were the QO2 (state 3); ADP/O ratio and oxidative phosphorylation; the mitochondrial, loosely bound (chelateable) iron (LB-iron); the xanthine dehydrogenase and xanthine oxidase activities. Inclusion of desferal in the perfusion solution significantly improved mitochondrial function during the different NICA periods, and prevented the deterioration of mitochondrial function resulting from reperfusion. Desferal did not significantly affect the LB-iron content of the mitochondria or the ratio of xanthine dehydrogenase/xanthine oxidase activities in the mitochondria during NICA or reperfusion. Our experiments suggest that iron, which is free to be chelated by desferal, plays a role in this injury to the rat myocardium.

Animals↗