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Biomedical subjects

C J Bates

Publications and source records attributed to C J Bates.

At least 127 records · Page 7Linked to original sources
PubMed1987

Bicycling performance in Gambian children: effects of supplements of riboflavin or ascorbic acid.

Sixty rural Gambian children between 10 and 14 years of age with normal haematological status but generally poor riboflavin status and some evidence of poor ascorbic acid status were recruited for study at the beginning of the rainy season. Children were allocated to three treatment groups to receive, twice weekly, either a placebo or a supplement of riboflavin or ascorbic acid. Before receiving the supplement, and on two subsequent occasions 6 weeks apart children performed an exercise regimen on a bicycle ergometer during which expired air was collected, heart rate monitored and lactate accumulation measured. A modest but significant improvement in ascorbic acid status occurred in response to supplement and the riboflavin supplement enhanced the overall improvement in riboflavin status observed. There was no measurable change in bicycling performance during the study period in any of the treatment groups.

Adolescent↗
PubMed1986

The effect of riboflavin deficiency on methylenetetrahydrofolate reductase (NADPH) (EC 1.5.1.20) and folate metabolism in the rat.

1. Riboflavin deficiency at two levels of severity was produced in weanling rats by feeding deficient diets for 6 weeks and using neck collars to prevent coprophagy. The severity of deficiency was monitored by growth, liver flavin levels and the activation coefficient of erythrocyte glutathione oxidoreductase (NAD(P)H) (EC 1.6.4.2). Control groups, receiving the same diet with ample added riboflavin, were fed either ad lib., or were pair-fed with the deficient animals. 2. The hepatic flavoenzyme, methylenetetrahydrofolate reductase (NADPH) (EC 1.5.1.20), was very markedly affected by severe riboflavin deficiency and was significantly, but less markedly, affected by the intermediate level of deficiency. This reduction in activity was due primarily to the direct effect of the diminished supply of riboflavin, and occurred to only a small extent as a result of inanition, demonstrated by a moderate reduction in activity in the more severely food-restricted of the two pair-fed groups. Since the enzyme is assayed in the presence of its flavin cofactor, FAD, it clearly cannot be reactivated in vitro, as some other depleted flavoenzymes can. The discriminatory ability in distinguishing between severe and moderate riboflavin deficiency in vivo confers some potential advantages on this oxidoreductase as a possible index of riboflavin status. 3. The hepatic activity of another key folate-metabolizing enzyme, dihydrofolate reductase (EC 1.5.1.3), was not diminished by riboflavin deficiency in the present study. 4. The ratio, labelled 5-methyltetrahydrofolic acid:other labelled compounds derived from intraperitoneally injected pteroylglutamic acid in extracts of hepatic tissue was significantly reduced in the riboflavin-deficient groups, indicating the possibility of an effect of riboflavin deficiency on folate metabolism in vivo.

Animals↗
PubMed1986

Carotene dioxygenase (EC 1.13.11.21) activity in rat intestine: effects of vitamin A deficiency and of pregnancy.

1. Female weanling rats were fed on a purified diet containing either no vitamin A, apart from traces present in casein (deficient groups), or the same diet containing 1.55 mg retinol as retinyl acetate/kg (control groups). In one experiment the deficient groups were given 1 microgram retinol/d after 10 weeks, to permit successful reproduction under conditions of marginal vitamin A status. A proportion were mated at 11 weeks after weaning, and fetal development was permitted for 7 d or for 20 d before killing. 2. Carotene dioxygenase (EC 1.13.11.21) activity was measured in a supernatant fraction from intestinal mucosal scrapings. For each group, activity was 20-30% greater in the vitamin-A-deficient animals than in the controls, and the difference reached statistical significance for the virgin and 7 d pregnant animals in the first experiment (severe deficiency) and for the 20 d pregnant animals in the second experiment (less-severe deficiency). 3. It is suggested that low tissue vitamin A levels may feedback to increase carotene dioxygenase activity, by mechanisms at present unknown, presumably to ensure a more efficient use of precursor dietary carotenoids.

Animals↗
PubMed1986

Dark adaptation in pregnant and lactating Gambian women: feasibility of measurement and relation to vitamin A status.

The feasibility of dark adaptation measurement, using a Friedmann Visual Field Analyser, was assessed under field conditions in an isolated rural community in The Gambia, West Africa. It was found to be possible to obtain meaningful and reliable measurements on nearly all of the 117 subjects tested in two communities. Measurements were made throughout the cycle of pregnancy and in early lactation. No deterioration was observed in the later stages of pregnancy, in contrast to the deterioration reported previously in some vitamin A-deficient communities. Nearly all measurements were within the normal range quoted by the manufacturer. No evidence of improved adaptation was detected in women receiving a food supplement containing vitamin A. There were moderate variations with age of subject and with season, although the latter were not closely correlated with variations in vitamin A intake. Better nourished Gambian and Caucasian subjects showed slightly better performance than the village subjects, but this seems simply to reflect their better understanding of the test, since a small learning effect was observed. It is concluded that, despite limited comprehension of the nature of the test, reliable measurements could, with care, be obtained on illiterate adults from an unsophisticated society, and that in the marginally nourished community studied, a substantial increase in vitamin A intake had no discernible effect in improving dark adaptation performance.

Adolescent↗
PubMed1986

Folate status during pregnancy and lactation in a West African rural community.

Red cell folate concentration was used to measure folate status in 89 rural Gambian women, 81 of whom were pregnant or lactating for the duration of the study. During pregnancy, the women received a haematinic supplement of 500 micrograms pteroyl glutamic acid and 47 mg iron a day, and a food supplement was also given to some of the women during either pregnancy, or lactation, or both. During pregnancy, the red cell folate levels reached a peak around the fifth month, attributable to the haematinic supplement. By the third month of lactation they had fallen back to a low plateau, which was below the accepted lower limit of normality in 56 per cent of those who did not receive a food supplement during lactation. In addition to these changes, there was a significant cyclical variation with season, peak values occurring in the rainy season. Plasma iron values followed the red cell folate patterns quite closely. Changes in blood haemoglobin levels during pregnancy were similar to those reported from other communities; there was also an increase in mean red cell volume during the first half of pregnancy, reaching a peak at the same stage as the peaks of red cell folate and plasma iron. There was no indication of the presence of raised cell volumes in association with low folate indices which might suggest megaloblastosis. It is concluded that the 500 micrograms daily folate supplement is both necessary and adequate to maintain red cell folate levels during pregnancy in this community, but that in the absence of further supplements during lactation, red cell folate levels will fall to undesirably low levels in many subjects by the third-to-sixth month of lactation.

Adolescent↗
PubMed1985

Normal vitamin requirements in neonates and infants.

Information about vitamin requirements by neonates and infants has been derived from studies of the composition of breast milk, from feed-response trials, from the occurrence of overt deficiency in infants fed damaged milk formulae, and by extrapolation from experimental deficiency studies on adult humans and on animals. Our knowledge is far from complete, however, and dietary recommendations have been formulated for only about half the known vitamins in the UK. In the near future, studies with stable isotope-labelled vitamins should help to define pool sizes and turnover rates that are associated with particular intakes and thus give firmer evidence about requirements.

Ascorbic Acid↗
PubMed1985

Effect of riboflavin deficiency on reproductive performance and on biochemical indices of riboflavin status in the rat.

Young female rats were made riboflavin-deficient by feeding a purified diet containing casein (210 g/kg). This basal diet provided 0.40 mg riboflavin/kg diet, to which was added additional riboflavin at 0, 0.12 or 0.25 mg/kg diet. Control animals received the same diet with 15 mg added riboflavin/kg. The diets were given for 4 weeks before mating, then throughout pregnancy and for 15 d of lactation. With no added riboflavin in the diet, reproduction was severely impaired and fetal resorption was usually observed. With 0.12 mg added riboflavin/kg diet, however, reproduction was usually successful, and the growth of dams and pups was only marginally depressed in comparison with pair-fed controls optimally supplied with riboflavin. The activation coefficient (stimulated:basal activity) of erythrocyte glutathione reductase (NAD(P)H) (EC 1.6.4.2) was high, and the concentration of riboflavin in the liver was correspondingly low in the dams receiving diets containing 0.12 or 0.25 mg added riboflavin/kg and in their sucking pups at 15 d post partum. Riboflavin levels in the milk from both groups of dams were about eightfold lower than in controls. There was little evidence that the sucking pups could maintain their riboflavin level at the expense of that in the maternal tissues.

Animals↗
PubMed1985

Effect of riboflavin deficiency on lipid metabolism of liver and brown adipose tissue of sucking rat pups.

An increase in liver: body-weight and in hepatic triacylglycerol content, together with changes in the fatty acid profiles of hepatic phospholipids, were observed as a result of moderate riboflavin deficiency in sucking rat pups. Oxygen consumption by hepatic mitochondria, with palmitoyl L-carnitine as substrate, was not significantly impaired. Mitochondria from interscapular brown adipose tissue, however, showed a marked impairment of O2 consumption, with palmitoyl L-carnitine as substrate, in the riboflavin-deficient pups. This impairment was also apparent after uncoupling with carbonyl cyanide p-trifluoromethoxyphenylhydrazone, but was not consistently observed after the addition of GDP to suppress uncoupled oxidation. It was much less evident, and did not reach statistical significance, for the mitochondria of brown adipose tissue of the corresponding deficient dams. Binding of 3H-labelled GDP by brown adipose tissue mitochondria was unaffected by riboflavin deficiency in the pups, suggesting that the effect on O2 consumption is more likely to be due to impaired integrity of the mitochondrial respiratory chain, than to impairment of the specific capacity for uncoupling of respiration which is characteristic of brown adipose tissue mitochondria. Total cytochrome c oxidase (EC 1.9.3.1) activity of the brown adipose tissue of riboflavin-deficient pups was not significantly reduced. A small but significant impairment was observed in the stimulation of whole-body O2 consumption by injected noradrenaline in the riboflavin-deficient pups, suggesting that the impairment of brown adipose tissue mitochondrial function may be accompanied by impaired physiological capacity in vivo.

Adipose Tissue, Brown↗
PubMed1985

Susceptibility of riboflavin and vitamin A in breast milk to photodegradation and its implications for the use of banked breast milk in infant feeding.

Up to 50% of the riboflavin and up to 70% of the vitamin A in human drip breast milk samples were destroyed during controlled exposure to daylight, either in translucent polythene bottles, or where the milk was pumped through naso-gastric tubing from a syringe to mimic the conditions of enteral feeding. Losses were also observed in milk which was exposed to standard phototherapy illumination under conditions similar to those encountered in the ward, and in this case riboflavin was destroyed to a greater extent than vitamin A. Photodegradation of riboflavin may contribute to the high incidence of biochemical riboflavin deficiency reported in preterm infants receiving breast milk without vitamin supplements. The implications of these findings for feeding high risk term and preterm infants on donor milk are discussed, and the use of low actinic vessels and tubing to minimise photodegradation is recommended.

Female↗
PubMed1985

A simple fluorimetric assay for pyridoxamine phosphate oxidase in erythrocyte haemolysates: effects of riboflavin supplementation and of glucose 6-phosphate dehydrogenase deficiency.

The formation of pyridoxal and its phosphate from pyridoxamine phosphate by red cell haemolysates was measured in a centrifugal analyser by the formation of the fluorescent adduct with semicarbazide. Pyridoxal phosphate was found to react more rapidly than pyridoxal, thus permitting a distinction between the two products, and hence the measurement of phosphatase activity. Activity of the enzyme, pyridoxamine phosphate:oxygen oxidoreductase (deaminating) EC 1.4.3.5 (PPO) was measured in haemolysates from 72 Gambian women with evidence of riboflavin deficiency, and was repeated after 6 weeks of placebo or riboflavin supplementation. Those who received the riboflavin supplement responded with a marked increase in PPO activity, which was matched by a decrease in the activation coefficient (AC) of erythrocyte NAD(P)H2:glutathione oxidoreductase, EC 1.6.4.2 (glutathione reductase, EGR). No difference between the supplemented and unsupplemented groups was observed in the capacity of haemolysates to hydrolyse pyridoxal 5-phosphate, nor in the extent of activation of erythrocyte L-aspartate:2-oxoglutarate aminotransferase EC 2.6.1.1. by pyridoxal phosphate. Although the three subjects with low levels of D-glucose 6-phosphate: NADP 1-oxidoreductase EC 1.1.1.49 (G6P-D) had, as expected, correspondingly low AC's of EGR, their unsupplemented activities of PPO were in the same low range as those of the G6P-D-normal subjects, and they responded as G6P-D-normal subjects did to riboflavin supplementation. PPO thus does not appear to resemble EGR in retaining its flavin coenzyme during riboflavin depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Haematological response to supplements of iron and riboflavin to pregnant and lactating women in rural Gambia.

Eighty-one pregnant or lactating women living in a village in The Gambia were allocated to treatment groups to receive a daily placebo, riboflavin, ferrous sulphate or ferrous sulphate plus riboflavin. At the beginning of the study and at 3 and 6 weeks thereafter women were examined clinically and blood samples collected for haematological and biochemical measurements. Pregnant women showed a wide range of response to supplement but among the lactating women an interesting pattern emerged: whereas the haematological status of the placebo group declined over 6 weeks, in the group receiving iron supplements this deterioration was reduced although not significantly. Riboflavin given in addition to iron resulted in a significant increase in circulating plasma iron and in iron stores, relative to the placebo.

Anemia, Hypochromic↗
PubMed1985

Effects of a multivitamin and iron supplement on running performance in Gambian children.

Forty boys and girls between 11 and 14.5 years with evidence of subclinical vitamin deficiencies were allocated to two groups to receive, twice weekly, either a placebo or a multivitamin and iron supplement. Prior to supplementation and on two subsequent occasions about 5 weeks apart, the children performed an exercise regimen on a treadmill during which expired air was collected and heart rate monitored. The supplement resulted in marked improvements in riboflavin and vitamin C status and checked the decline in iron stores seen in the unsupplemented children. During the study the running performance of unsupplemented children deteriorated, and markedly so in a subgroup with initially poor nutrient status. The vitamin and iron supplement prevented this deterioration so as to produce a significant reduction in the energy cost of treadmill running in the more malnourished subgroup, relative to the changes seen in children receiving no supplement.

Adolescent↗
PubMed1984

Seasonal variations in plasma retinol and carotenoid levels in rural Gambian women.

Plasma carotenoid levels exhibited a major seasonal variation in pregnant and lactating women in Keneba, a rural Gambian village. This is probably due mainly to the seasonally related contribution of mangoes, which are a major dietary component during May and June, but are essentially unavailable for the remainder of the year. Plasma retinol levels, on the other hand, exhibited much less seasonal variation, although a trend towards higher levels in May and June was just discernible. Plasma retinol levels were significantly lower than those observed in a group of pregnant and lactating women living in the UK.

Carotenoids↗
PubMed1984

Effects of pregnancy and riboflavin deficiency on some aspects of iron metabolism in rats.

Using female Norwegian hooded rats on controlled dietary intakes we have looked at the effects of pregnancy, and of riboflavin status, on levels of circulating iron, hepatic ferritin, iron stores and iron mobilisation in vitro from ferritin. Results suggest that pregnancy, and rapid growth, increase the demand for iron turnover, and deplete ferritin stores, and that riboflavin deficiency may impair iron mobilisation for these purposes.

Animals↗
PubMed1984

Efficacy of a food supplement in correcting riboflavin deficiency in pregnant Gambian women.

Pregnant women living in rural Gambian villages, whose natural riboflavin intake is about 0.5 mg/d, have abnormal biochemical riboflavin status and signs of clinical deficiency. A vitamin-fortified food supplement given in one village which increased the riboflavin intake to about 1.3 mg/d was followed by a substantial improvement in biochemical status, although seasonally-related variations in status somewhat complicated the picture. It was calculated that the amount of riboflavin needed to satisfy the requirement, for normal biochemical status, of the majority of pregnant women throughout pregnancy and throughout the year, is about 2.6 mg/d. Clinical signs associated with riboflavin deficiency, especially atrophic lingual papillae, showed significantly reduced incidence in the supplemented, compared with an unsupplemented, village. Cord blood values of the activation coefficient of erythrocyte glutathione reductase were in the abnormal range for 84 per cent of infants before introduction of the supplement, but were abnormal for only one of 12 infants after its introduction. Thus even a suboptimal maternal riboflavin intake of about 1.3 mg/d appears to be sufficient to prevent biochemical deficiency in cord blood, and to reduce considerably the incidence of clinical deficiency signs during pregnancy.

Adult↗
PubMed1983

A trial of ascorbic acid and of multivitamin supplementation on the oral health of West African children.

204 children between the ages of 1.5 and 6.5 years living in a West African village where the incidence of gingivitis and bleeding gums is about 40% of the population at the end of the rainy season, were given vitamin C or a placebo for 69 days, followed by a multivitamin supplement or placebo for 47 days. The condition of their gums was continuously monitored by trained field workers and by a paediatrician during the supplementation period, and was also assessed in greater detail by the paediatrician at the beginning and end of each treatment period. No benefit of either type of supplement could be detected, either on incidence of bleeding, or on over-all severity of gingivitis, although there was a clear-cut seasonal trend towards lower incidence of bleeding in both groups as the study progressed.

Ascorbic Acid↗