In vitro permeation of platinum through African and Caucasian skin.

The majority of the South African workforce are Africans, therefore potential racial differences should be considered in risk and exposure assessments in the workplace. Literature suggests African skin to be a superior barrier against permeation and irritants. Previous in vitro studies on metals only included skin from Caucasian donors, whereas this study compared the permeation of platinum through African and Caucasian skin. A donor solution of 0.3 mg/ml of potassium tetrachloroplatinate (K2PtCl4) dissolved in synthetic sweat was applied to the vertical Franz diffusion cells with full thickness abdominal skin. Skin from three female African and three female Caucasian donors were included (n=21). The receptor solution was removed at various intervals during the 24 h experiment, and analysed with high resolution inductively coupled plasma-mass spectrometry (ICP-MS). Skin was digested and analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES). Significantly higher permeation of platinum through intact African skin (p=0.044), as well as a significantly higher mass of platinum retention in African skin in comparison with Caucasian skin (p=0.002) occurred. Significant inter-donor variation was found in both racial groups (p<0.02). Results indicate that African workers have increased risk of dermal permeation and therefore possible sensitisation caused by dermal exposure to platinum salts. These results are contradictory to limited literature suggesting a superior barrier in African skin and further investigation is necessary to explain the higher permeation through African skin.

In vitro permeation of platinum and rhodium through Caucasian skin.

During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace.

Dermal exposure sampling methods: an overview

Although a total of 174 and 117 substances have been listed with a skin (Sk) notation in the Regulations for Hazardous Chemical Substances and Regulation 22.9 of the Mine Health and Safety Act respectively; dermal sampling is not used frequently to assess exposure to these substances. A variety of measurement methods and strategies have been developed during the past forty years to assess dermal exposure. These methods include interception methods (also referred to as surrogate skin methods); removal of contaminant (substance) methods and in situ detection methods (also referred to as fluorescent tracer methods). The aim of this paper is to give an overview of the different dermal sampling methods. Furthermore; the applicability of each method for sampling different hazardous chemical substances will be highlighted in order to assist Occupational Hygienists in choosing the correct dermal sampling method

Plasma fibrinogen of black South Africans: the BRISK study.

OBJECTIVE: To describe the distribution of plasma fibrinogen and relationships with other risk factors for coronary heart disease (CHD) and stroke in the black population of the Cape Peninsula. DESIGN: A cross-sectional survey of a stratified proportional sample of randomly selected black men and women. SETTING: Households in Gugulethu, Langa, Nyanga, New Crossroads, KTC, Old Crossroads and Khayelitsha in the Cape Peninsula, South Africa. SUBJECTS: One subject per household (352 men and 447 women), aged 15-64 years, voluntarily participated. Visitors, pregnant, lactating, ill, mentally retarded and intoxicated subjects were excluded. RESULTS: Mean fibrinogen (thrombin time coagulation method) of men and women were higher than published data for Europeans but slightly lower than values of black Americans. Women aged 45-54 years had the highest level (3.13+/-0.89 g l(-1)) and men aged 15-24 years had the lowest (2.13+/-0.88 g l(-1)). Fifteen per cent of the men and 12% of the women had a level greater than 1 standard deviation of the mean for their age group. Univariate and multivariate analyses revealed significant (P<0.05) positive correlations of fibrinogen with smoking habit, age, body mass index (BMI), total and low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure and white blood cell count, and significant negative correlations with high-density lipoprotein (HDL) cholesterol, gamma glutamyl transferase (GGT), serum iron and ferritin. The correlations with BMI, serum lipoproteins, iron, ferritin, and GGT suggest that nutritional status and therefore diet influences plasma fibrinogen. CONCLUSION: Relatively high fibrinogen levels, tending to cluster with other, including diet-related, risk factors for CHD and stroke, were observed in black South Africans. It is suggested that fibrinogen may contribute to the high stroke incidence of this population group.

Response to an iron fortification programme in relation to vitamin A status in 6-12-year-old school children.

Plasma retinol and indices of iron status were measured in 148 school children (6-12 years) receiving a soup fortified with iron and vitamin C for a period of 15 weeks. The most significant change in serum iron (P = 0.0005) and transferrin saturation (P = 0.0002) was seen in subjects with plasma retinol > or = 40 micrograms/dl, while subjects with plasma retinol < 20 micrograms/dl showed no response. Serum ferritin improved most in the retinol categories < 40 micrograms/dl, suggesting that the absorption of iron was not impaired by marginal vitamin A status, but that it was rather the mobilisation of iron from stores that was affected. Changes in vitamin A status correlated positively and significantly with changes in serum iron (r = 0.37; P = 0.0001) transferrin saturation (r = 0.27; P = 0.004) and haemoglobin (r = 0.21; P = 0.03), but negatively with serum ferritin (r = -0.28; P = 0.003). The presence of marginal vitamin A deficiency in a community may limit the effectiveness of an iron intervention programme and vitamin A status should therefore also be considered when such programmes are planned.

The lipid and lipoprotein profile of the urban black South Africa population of the Cape Peninsula - the BRISK study.

OBJECTIVE: To determine the lipid and lipoprotein profile of the urban black South African population of the Cape Peninsula. DESIGN: Cross-sectional design. SETTING: The seven black residential areas of the Cape Peninsula. PARTICIPANTS: A stratified proportional sample was drawn from the study area. The sample consisted of 422 men and 544 women aged between 15 and 64 years. OUTCOME MEASURES: Lipid and lipoprotein levels. Risk levels for coronary heart disease (CHD). RESULTS: The total cholesterol (TC level) was low compared with other South African groups studied. Men had a mean TC of 3.98 mmol/l and women 4.15 mmol/l. Low-density lipoprotein cholesterol (LDLC) values for men (2.03 mmol/l) were lower than those for women (2.30 mmol/l). Men (1.35 mmol/l) and women (1.37 mmol/l) had similar high-density lipoprotein cholesterol (HDLC) levels. Both sexes had a prevalence of protective HDL/TC ratios above 30% for all age groups. High HDL3C levels and low HDL2C levels were found in both men and women. Apolipoprotein A and B followed the trends of HDLC and LDLC and showed no difference between the sexes. The plasma triglyceride (TG) levels increased with age in both sexes. Men displayed higher TG levels than women in all age groups. Seventeen per cent of men and 26% of women had a moderate-to-high risk for CHD, given their TC levels. Other lipid-related risk factors indicated low risk for CHD.

Oesophageal and other cancer patterns in four selected districts of the Transkei, Southern Africa:1985-1990.

New data regarding the incidence of oesophageal and other cancers during the period 1985-1990 are reported for all clinics and hospitals in four selected districts of Transkei, Southern Africa i.e. Kentani, Butterworth, Lusikisiki and Bisana. Active and passive methods were used to obtain the hospital-based cancer registry data. The mean annual number of cancer cases recorded for the period 1985-1990 was 292. Age-standardised incidence rates (ASIR, African standard) for all recorded cancer were 81.4 and 52.6/100,000 for males and females respectively. Histopathological examination of 52.6% of recorded tumors revealed that 67.3% were squamous carcinomas, 21.7% adenocarcinomas and the remainder non-epithelial neoplasm. Cancer of the oesophagus (OC) was the most frequently recorded cancer and accounted for the 46.5% of the cases with mean ASIR of 46.7 and 19.2/100,000 for males and females respectively. The male/female ratio was 2.4:1. The highest mean ASIR per annum for OC in males (55.6/100,000) occurred in Kentani and in females (22.3/100,000) in Lusikisiki, whereas the lowest rates in both sexes (37.0 and 11.7/100,000 respectively) occurred in Bizana. Comparison of the OC rates in the four districts of Transkei during 19985-1990 with previous reported trends, confirms a consistently high rate in the south-western districts of Kentani during the past 35 years and progressively increasing rates in the north-eastern districts of Bizana and Lusikisiki. These results have profound implications for further epidemiological and aetiological studies on OC in Transkei, but we need to be corroborated by data form other sources such as statistics on histologically diagnosed cancer in Transkei by districts in the South African National Cancer Registry. The second most frequent recorded cancer among males was liver cancer with a mean annual ASIR of 6.0/ 100,000 and male:female ratio of 3:1. The most frequent recorded cancer among females was cervical cancer with a mean annual ASIR of 20.9/100,000 followed by OC (19.2/100,000) and breast cancer (5.8/100,000).

Epidemiology and control of schistosomiasis mansoni in communities living on the Cuando River floodplain of East Caprivi, Namibia.

The Cuando River area of eastern Caprivi, Namibia, is highly endemic for Schistosoma mansoni whereas S. haematobium transmission, due to the scarcity of its intermediate host snail, Bulinus africanus, does not occur. Chemotherapy (6-monthly blanket treatments with praziquantel) combined with focal mollusciciding (monthly application of niclosamide) was used in a project in the area to control the disease. Although as many adults and pre-school children as possible were tested and treated, the project concentrated largely on school-age children. It took 3 years for prevalence to decline from > 80% to 20% because of a lack of proper sanitary facilities and piped water supplies and high rates of absenteeism and re-infection. However, intensity of infection decreased more rapidly, from an arithmetic mean of > 200 to < 5 eggs/g faeces. Hepatomegaly was common among school children when the project started but could be seen in only a small percentage of them after 3 years of control. Neither the bovine schistosome, S. mattheei, nor the lechwe schistosomes, S. margrebowiei and S. leiperi, were observed in the excreta of humans living in the area.

The haematological profile of urban black Africans aged 15-64 years in the Cape Peninsula.

A stratified probability sample (n = 986) with quotas was drawn from black residential areas in the Cape Peninsula, South Africa. Subjects (n = 819) aged 15-64 years, participated in a coronary heart disease (CHD) risk factor survey, the BRISK Study. Nutritional status and prevalence of CHD was determined in this population undergoing rapid urbanization. Full blood and differential white blood cell counts provided data to calculate population reference values based on the 95% reference limits of the haematological parameter. Mean haemoglobin concentrations (Hb) in men (14.0 g/dl) and women (12.4 g/dl) were +/- 1.5 g/dl lower than previous South African reports. Mean BRISK Hb values were very similar to the World Health Organization's Hb cutoff criteria (< 13 g/dl men; < 12 g/dl women), indicating a possible high prevalence of anaemia. Significantly higher (P < 0.05) mean values for red cell indices were confirmed in men, which also reflected equally higher red blood cell counts (RBC), haematocrit (HCT) and mean corpuscular haemoglobin (MCH) values. Mean Hb values were significantly lower in the younger (15-24 years) and older (55-64 years) men compared with 25-54 year-olds (P < 0.05). Hypochromic microcytic anaemia was more prevalent in women, possibly due to iron deficiency (ID), while macrocytic anaemia was more prevalent in men. No significant differences were noted in mean total and differential white blood cell counts (WBC) between men and women.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of iron fortification on the fatty acid composition of plasma and erythrocyte membranes in primary school children with and without iron deficiency.

An intervention study was designed to evaluate the fatty acid (FA) status of children aged 6-11 years before and after iron fortification. Iron-deficient (ID) and matched controls without ID (n = 30) were selected. All children received soup (160 ml) fortified with 20 mg iron and 100 mg vitamin C for 15 weeks on school days. Measurements before and after intervention included dietary intake, haematological and iron status and FA composition of plasma and erythrocyte membranes (EMBs). The prevalence of low plasma ferritin concentration and transferrin saturation decreased in the ID children by 40% and 56%, respectively, with intervention. Plasma FAs reflected dietary FA intake. In comparison with controls, the ID group presented with increased percentage total saturated FAs (SFAs; p = 0.0002) in their EMB phosphatidylcholine (PC) and reduced percentage total polyunsaturated FAs (PUFAs; p = 0.0037) before intervention. Lower total n-3 FAs (p = 0.0070), including eicosapentenoic acid (EPA; p = 0.0034), docosapentenoic acid (DPA; p = 0.0048) and docosahexenoic acid (DHA; p = 0.0058), were observed in the ID group. The EMB phosphatidylethanol-amine (PEA) of the ID children presented with lower percentages of alpha-linolenic acid (ALA; p = 0.0001), EPA (p = 0.0051) and DHA (p = 0.0084) compared to controls before intervention. Iron intervention was associated with an increase (p < 0.05) in the percentage of n-3 FAs in the EMB-PC and EMB-PEA of the ID group to percentages comparable to that in the control group. It appears that iron status can influence FA metabolism of specific n-3 FAs in the EMBs of young children.

The effect of iron fortification on the fatty acid composition of plasma and erythrocyte membranes in primary school children with and without iron-deficiency.

An intervention study was designed to evaluate the fatty acid (FA) status of children aged 6-11 years before and after iron fortification. Iron deficient (ID) and matched controls without ID (n = 30) were selected. All children received soup (160 mL) fortified with 20 mg iron and 100 mg vitamin C for 15 weeks on school days. Measurements before and after intervention included dietary intake, haematological and iron status and FA composition of plasma and erythrocyte membranes (EMBs). The prevalence of low plasma ferritin concentration and transferrin saturation decreased in the ID children by 40% and 56%, respectively, with intervention. Plasma FAs reflected dietary FA intake. In comparison with controls, the ID group presented with increased percentage total saturated FAs (SFAs; p = 0.0002) in their EMB phosphatidylcholine (PC) and reduced percentage total polyunsaturated FAs (PUFAs; p = 0.0037) before intervention. Lower total n-3 FAs (p = 0.0070) including eicosapentaenoic acid (EPA; p = 0.0034), docosapentaenoic acid (DPA; p = 0.0048) and docosahexaenoic acid (DHA; p = 0.0058) were observed in the ID group. The EMB phosphatidylethanolamine (PEA) of the ID children presented with lower percentages of alpha-linolenic acid (ALA; p = 0.0001), EPA (p = 0.0051) and DHA (p = 0.0084) compared to controls before intervention. Iron intervention was associated with an increase (p < 0,05) in the percentage of n-3 FAs in the EMB-PC and -PEA of the ID group to percentages comparable to that in the control group. It appears that iron status can influence FA metabolism of specific n-3 FAs in the EMBs of young children.

Nutritional status of primary school children with endemic goitre in Caprivi, Namibia.

The nutritional status of primary school children living in an endemic goitre area in eastern Caprivi, Namibia, was assessed by means of clinical, biochemical, anthropometrical and dietetic observations. An approximately 20 pc sample, consisting of 380 primary school children, aged six to 18 years and representing eight schools in the Cuando River area of eastern Caprivi, was included in the study. Their goitre prevalence of 34.5 pc has been reported earlier. A significantly lower mean thyroxine level in goitrous compared to non-goitrous children indicated that dietary iodine deficiency was the primary cause of the endemic goitre. The present paper focuses on the nutritional status of these primary school children. Anthropometrically, these children were severely undernourished, as indicated by a high prevalence of low (below the third NCHS percentile) weight and height for age values, ranging from 38.0 pc to 55.9 pc. Dietary analysis revealed a low energy intake as well as dietary deficiencies in folic acid (only girls), ascorbic acid, vitamin A, nicotinic acid, iron, riboflavin and calcium. A high percentage (43.9 pc of boys and 33.7 pc of girls) of the children were biochemically anaemic whilst less than one pc of the children showed clinical signs of anaemia. Nutritional intervention programmes in this area should not only treat and prevent the endemic goitre but also attend to the energy and micro-nutrient deficiencies in these children.

PIP: In Namibia, a nutrition survey was conducted among 380 children aged 6-18 years at 8 primary schools along the Cuando River over about a 100 km stretch, in eastern Caprivi. This is a goiter-endemic area. 34.5% of the children had a goiter, which was the most significant nutritional condition in primary school children. This high prevalence of goiter indicated a dietary iodine deficiency. Iodine deficiency disorder can cause neurological damage ranging from mild intellectual impairment to full-blown cretinism. 38% were underweight and 55.9% were stunted (i.e., 3rd percentile of the National Center for Health Statistics). 2% had clinical signs of either kwashiorkor or marasmus. 43.9% of boys and 33.7% of girls were biochemically anemic, but less than 1% were clinically anemic. Mean standard hemoglobin level was 12.46 for girls and 12.31 for boys. Maize made up most of the diet and was eaten 2.7 times/day/child. Few children ate bread. Caloric intake was poor (39% and 45% of WHO recommendations for boys and girls, respectively). The diet did not contain enough folic acid for girls. Nutritional deficiencies in the diet also included ascorbic acid, nicotinic acid, iron, vitamin A, riboflavin, and calcium. Adequate nutritional intakes were limited to protein, thiamin, and vitamin B12 and, for boys, folic acid. These findings suggest that subsistence farming does not provide these children enough energy to maintain normal growth in children. This goiter-endemic area along the Cuando River needs educational and agricultural intervention programs to reverse endemic goiter and poor nutritional status. They should include treatment and prevention of goiter but also treatment and prevention of energy and nutrient deficiencies.

Endemic goitre among undernourished schoolchildren in eastern Caprivi, Namibia.

A cross-sectional study on a 20% random sample of 380 children, aged 6-18 years, from 8 primary schools in the Cuando River area of eastern Caprivi, Namibia, was done to determine the prevalence of goitre and to investigate related hormonal and nutritional factors. Of the children 34.5% had goitre. Reduced plasma free thyroxine concentrations in the more severely goitrous children, compared with matched non-goitrous children (P = 0.0007), implicated dietary iodine deficiency as the causative factor. Their diet was inadequate in energy and most nutrients according to World Health Organisation criteria. Retarded growth, indicated by their low body weight and height in relation to age, were observed in a large proportion (45.6-73%) of the children. These findings suggest that dietary iodine deficiency was the most likely cause for the endemic goitre in these children, who were predisposed to nutritional disorders by long-term undernourishment.

Atherogenic effects in a non-human primate of Fusarium moniliforme cultures added to a carbohydrate diet.

Adding less than 0.5% w/w of culture material of strain MRC 826 of the fungus Fusarium moniliforme to a carbohydrate diet low in fat resulted in an atherogenic plasma lipid profile in a non-human primate. Simultaneously increased plasma fibrinogen and activity of blood coagulation factor VII could enhance atherogenesis. This unique potential for promotion of atherosclerosis was probably secondary to chronic hepatotoxicity as indicated by liver fibrosis and elevated cholesterol, albumin and the enzymes AST, ALT, LD, GGT and ALP in serum. The cholesterol and enzymes responded in proportion to the calculated doses of fumonisin mycotoxins in the F. moniliforme MRC 826 cultures. Fumonisins are water soluble and heat stable. Thrombotic, hepatotoxic, carcinogenic and cerebral effects of MRC 826 culture material and fumonisins are well known in non-primates. The estimated fumonisin concentrations tested fall within a range due to natural contamination of human foods. The results suggest that all maize grain products should be analysed for fumonisins.

Risk factors for coronary heart disease in the black population of the Cape Peninsula. The BRISK study.

A cross-sectional study of risk factors for ischaemic heart disease (IHD) in a random sample of 986 black people aged 15-64 years living in the Cape Peninsula revealed a population at lower risk for IHD than other South Africans. Blood pressures of 140/95 mmHg or above were found in 14.4% of males and 13.7% of females. Fifty-two per cent of males and 8.4% of females smoked, while 16.5% of males and 25.8% of females had a total cholesterol (TC) level imparting risk for developing IHD. In this population the TC level is not a good surrogate measure for low-density lipoprotein cholesterol because of the high level of high-density lipoprotein cholesterol (HDLC) found in this population. A protective HDLC/TC ratio of 20% was found in 96% of males and 96.1% of females. When considering the three major reversible IHD risk factors at a high level of risk, 30.8% of males and 12.5% of females had at least one such a risk factor. The population was frequently exposed to the media, with 80% listening to the radio every day and 55% watching television at least once a week. This suggests that a healthy lifestyle could be promoted successfully by means of these media. In addition, schools should promote a healthy lifestyle and the prevention of chronic degenerative diseases should be incorporated into the evolving primary health care services in South Africa.

A stable non-prostaglandin inhibitor of platelet aggregation in human aorta intima extracts.

An inhibitor of platelet aggregation induced by adenosine diphosphate, collagen, adrenaline and thrombin is present in aorta intima extracts. The inhibitor is relatively stable and is not inactivated by prolonged incubation at 37 degrees C or 22 degrees C, but boiling for 15 seconds destroys it. It is not extracted by diethyl ether or chloroform, and is not affected by incubation with indomethacin or tranylcypromine. Platelet aggregation induced by arachidonic acid is not affected by this inhibitor. These results suggest that this inhibitor is not PGI2 (prostacyclin), a recently described potent anti-aggregatory agent generated by blood vessel microsomes.

ADPase activity of normal and atherosclerotic human aorta intima.

ADP plays a key role in platelet aggregation and the enzymatic removal of this nucleotide may be important in the pathogenesis of intravascular thrombosis and atherosclerosis. Aortic intima extracts have ADPase activity and is able to remove small quantities of ADP efficiently. ADPase activity was assayed by measuring the catabolism of 2 micrometer 14C-ADP (final concentration) by the tissue extracts. Extracts prepared from normal, moderately and severely atherosclerotic human aortic initimas showed a significant progressive decrease in ADPase activity with increasing atherosclerosis. ADPase activity of the arch, thoracic and abdominal regions of normal aortas did not vary significantly, and thus did not correlate with the anatomical distribution of atherosclerosis. Vascular ADPase activity seems relevant in thrombogenesis since it may be a link between blood platelets and blood vessel wall interaction.

In vitro binding of folates by body fluids.

It is useful to differentiate between saturated folate binders in serum (carrying endogenous folate) and unsaturated binders (investigated in the present study). These two groups of binders need not necessarily be chemically identical and the unsaturated binder may even be an in vitro artifact, especially when measured with non-physiological folates. Macromolecular binding of radio-active N-5-methyl tetrahydrofolic acid (CH3H4PteGlu) and/or folic acid (PteGlu) by human serum and urine was assessed by means of exhaustive saline dialysis, haemoglobin-coated charcoal adsorption, column chromatography with DEAE-Sephadex A-50, and sucrose gradient analysis. Binding was found to be minimal or absent. Charcoal adsorption showed a mean serum binding capacity of 0 mug/1. for PteGlu and 0.58 mug/1. for CH3H4PteGlu. In pregnancy the mean serum values were 0.23 mug/1. for PteGlu, 0.66 mjg/1. for CH3H4PteGlu, and with folate deficiency 0.30 mug/1. for PteGlu, 0.49 mug/1. for CH3H4PteGlu. Mean urinary folate binding was minimal (less than 0.5 mug/1.), and red cell haemolysate similarly revealed very low binding on exhaustive dialysis. Column chromatography showed that tracer doses of [14C]PteGlu added to serum migrated distally to the protein zone; [14C]CH3H4PteGlu similarly showed no evidence of protein binding. On a sucrose gradient [14C]PteGlu also separated clear of the protein zone.