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Biomedical subjects

C J Bates

Publications and source records attributed to C J Bates.

At least 163 records · Page 9Linked to original sources
PubMed1981

The influence of G-6-PD activity on the response of erythrocyte glutathione reductase to riboflavin deficiency.

Erythrocyte NAD(P)H2 glutathione oxidoreductase (EC 1.6.4.2.) activation coefficients (EGR AC) and D-glucose-6-phosphate: NADP 1-oxidoreductase, EC 1.1.1.49 (G-6-PD) activities were measured in 155 West African women to determine whether heterozygous G-6-PD deficiency produces false negative results in the EGR test for riboflavin deficiency. A positive correlation was found between EGR AC and G-6-PD activity demonstrating that heterozygous G-6-PD deficiency does result in abnormally depressed EGR AC values when G-6-PD activity is significantly reduced. However, heterozygous deficient genotypes with normal G-6-PD activity showed undepressed EGR AC values. These results indicate that, in its present form, the EGR test is not a suitable index of riboflavin status in subjects whose G-6-PD activity is less than 9 IU/g Hb when measured by the WHO-37 degrees assay.

Adult↗
PubMed1981

Plasma cholesterol and blood pressure in vegetarians.

Plasma cholesterol, high-density lipoprotein cholesterol (HDL) and blood pressure were examined in three hundred subjects with a special interest in 'health foods'. The 85 vegetarians showed on average a lower total cholesterol and higher HDL per cent than the 214 non-vegetarians. The vegetarians were also leaner than the non-vegetarians in each age group in both sexes. No consistent differences were found in blood pressure. The vegetarians took more dietary fibre than the non-vegetarians and the possibility that this may be relevant to the other differences found will be examined further.

Adult↗
PubMed1980

Refection in rats fed on a sucrose-based, riboflavin-deficient diet.

1. Refection, resulting in an increased supply of riboflavin to riboflavin-deficient rats through coprophagy, was demonstrated on a sucrose-based diet when sensitive biochemical tests of riboflavin status were employed: these included measurements of NAD(P)H2:glutathione oxidoreductase (EC 1.6.4.2); succinate:(acceptor) oxidoreductase (EC 1.3.99.1) and NADH:(acceptor) oxidoreductase (EC 1.6.99.3). 2. The use of tail-cups to eliminate coprophagy, and hence refection, resulted in a more rapid and reproducible progress into severe deficiency. 3. The occurrence of refection on a sucrose-based diet may account for hitherto unexplained differences between previous publications on the biochemical effects of riboflavin deficiency.

Animals↗
PubMed1980

Folate status and its relation to vitamin C in healthy elderly men and women.

Plasma and red-cell folate levels and dietary folate intake were monitored for about six months, including two months during which supplementary vitamin C was given, in 21 healthy elderly men and women living at home in the north of England. Although biochemical values were consistently low in some subjects, no clinical folate deficiency was detected. Dietary folate intake was significantly correlated with red-cell folate, but not with plasma folate. Before vitamin C supplementation, folate intake was significantly correlated with vitamin C intake, and plasma, but not red-cell, folate was significantly related to plasma and buffy-coat vitamin C levels. During the period of vitamin C supplementation, no significant changes in plasma or red-cell folate levels were detected, even in subjects who had low initial levels of circulating vitamin C.

Aged↗
PubMed1979

Long-term vitamin status and dietary intake of healthy elderly subjects. 1. Riboflavin.

1. Long-term clinical and biochemical riboflavin status and dietary intake of riboflavin were monitored for 18 months in a group of twenty-three relatively-healthy elderly subjects living at home in the north of England. 2. Both dietary intake and biochemical status, as measured by the activation coefficient (stimulated:basal activity) of NAD(P)H2:glutathione oxidoreductase (EC 1.6.4.2), remained fairly constant for each individual and for most subjects the usual intake and biochemical status were characterized quite accurately by a single week's intake dietary record and a single measurement of the activation coefficient. 3. The expected relationship between biochemical status and dietary intake was present, but not strongly evident. There was a significant within-subject correlation between alpha values and the immediately preceding dietary intake; however the between-subject correlation between alpha values and dietary intake approached zero if the two subjects receiving long-term riboflavin supplements were omitted. Over the limited range of intakes observed in unsupplemented subjects, non-dietary factors evidently obscure the relationship. 4. Although eight subjects had average values above 1.2 for the activation coefficient, no excessively high values were observed, and no subject showed any clear-cut clinical deficiency symptoms.

Aged↗
PubMed1979

Vitamin C, high density lipoproteins and heart disease in elderly subjects.

Plasma vitamin C, total and high density lipoprotein (HDL) cholesterol and cortisol levels were measured in a random sample of 337 elderly subjects living at home in S. Wales; measurements of relative body weight and information about fruit intake, smoking habits and symptoms of cardiovascular disease were also collected. There was a sex difference, over all age groups, in plasma vitamin C and in total HDL cholesterol levels. Plasma vitamin C was strongly correlated with fruit intake in both sexes. Both HDL cholesterol and low and very density lipoprotein (LDL + VLDL) cholesterol levels tended to increase with increasing plasma vitamin C but this reached significance only for the LDL + VLDL fraction. In addition, HDL cholesterol was negatively correlated with Quetelet's index in the women. Symptoms and medication for heart disease did not correlate significantly with plasma vitamin C or with HDL cholesterol levels, but reported angina showed a weak positive association with total cholesterol in the men, and there was some evidence of increased cortisol levels in subjects with heart disease.

Aged↗
PubMed1979

Vitamin C deficiency in guinea pigs: variable sensitivity of collagen at different sites.

1. The synthesis of collagen in several tissues, including the C1q component of complement in serum, was measured in vitamin C-deficient and control guinea pigs by incorporating labelled proline into hydroxyproline in vivo. 2. Of the tissues examined, by far the greatest specific effect of vitamin C deficiency was observed in skin. Bone was second in order of sensitivity; skeletal muscle, lung, heart and kidney exhibited only small effects, which were difficult to distinguish from those of inanition, while liver, C1q, and the ethanol-soluble components of serum were virtually insensitive. The effect on urinary hydroxyproline was also extremely small. 3. The lack of sensitivity of C1q confirms previous conclusions (BATES, LEVENE, OLDROYD and LACHMANN 1978), based on total protein bound hydroxyproline levels and total C1 activity in plasma. Since C1q, which turns over rapidly, is insensitive, the high sensitivity of "repair" tissues to vitamin C deficiency is unlikely to be connected with their high turnover rate. Differential concentration of vitamin C by different tissues seems more likely to be the critical factor.

Adrenal Glands↗
PubMed1979

Vitamin C deficiency in guinea pigs: changes in urinary excretion of proline, hydroxyproline and total amino nitrogen.

1. The age-related decrease in hydroxyproline : creatinine ratio in young guinea pigs was significantly smaller in vitamin C-deficient animals than in pair-fed controls. The same was true for proline : creatinine and total amino nitrogen : creatinine ratios, but hydroxyproline : total amino nitrogen and proline : total amino nitrogen ratios were not significantly affected by deficiency. 2. Although the proline : hydroxyproline ratio was unaffected in unfractionated urine, acute or chronic deficiency produced a small but significant increase in this ratio in collagenase digests of the acetone-insoluble fraction. 3. In scorbutic animals, therefore, collagen probably turns over more rapidly than in animals matched for inanition. Some at least, of this increase could represent the rapid turnover of underhydroxylated nascent collagen. Because it contains the degradation products from collagen from many tissues, differing widely in sensitivity to vitamin C status, the urine is unlikely, however, to provide a specific and sensitive functional index of vitamin C status.

Animals↗
PubMed1977

Proline and hydroxyproline excretion and vitamin C status in elderly human subjects.

1. Plasma and buffy-coat vitamin C, urinary proline, hydroxyproline, creatinine and total amino acid concentrations were meausred in 23 healthy elderly subjects at intervals of 3 months. 2. There was a strong positive correlation between plasma vitamin C and buffy-coat vititamin C. 3. There were not significant correlations between plasma or buffy-coat vitamin CPAMIN C. 3. There were not significant correlations between plasma or buffy-coat vitamin C and total urinary hydroxyproline, whether expressed on a creatinine basis or on a total amino acid basis. Similarly, no significant correlations could be detected involving the proline/hydroxyproline ratio in urine hydrolysates. 4. There was a significant negative correlation between plasma or buffy-coat vitamin C and total urinary proline, when expressed per unit of total urinary proline, when expressed per unit of total urinary proline, when expressed per unit of total amino acids in the hydrolysates. This correlation was not observed with unhydrolysed urine, and it appeared to reside in the diffusible fraction, part of whose proline could be liberated by prolidase digestion. In addition, in the man, there was some evidence for a positive correlation between plasma or buffy-coat vitamin C and the ratio of total urinary amino acids to creatinine. 5. These results support the view that poor vitamin C status in elderly humans may be associated with a defect in collagen proline hydroxylation, reflected by increased excretion of proline-rich, collagen-derived peptides. If this interpretation is correct, it indicates a potential defect in connective tissue repair, and could form the basis of a functional test for subclinical vitamin C deficiency.

Aged↗
PubMed1977

The effect of riboflavin deficiency on white cell glutathione reductase in rats.

1. The measurement of glutathione reductase in white cells from peripheral rat blood is described; the contribution from red cell glutathione reductase was virtually eliminated. 2. The activation of the white cell enzyme by flavin adenine dinucleotide (FAD) in vitro was measured during an eight week period of dietary riboflavin deficiency in weanling rats. 3. The activation increased progressively during the deficiency reaching about fifty per cent after eight weeks, at which time liver FAD levels had declined to 30% of the control levels and clinical symptoms of deficiency were beginning to appear. No increase in activation of white cell glutathione reductase was observed in pair-fed controls, over this time period. 4. These observations suggest that the measurement of the activation coefficient of white cell glutathione reductase could usefully supplement that of the red cell enzyme, in defining riboflavin status.

Animals↗
PubMed1976

The effect of hypoxia on collagen synthesis in cultured 3T6 fibroblasts and its relationship to the mode of action of ascorbate.

When exposed to low oxygen tension, in the absence of added ascorbic acid 3T6 mouse fibroblast cultures in late log phase respond by increased lactate production and increased hydroxylation of proline in nascent collagen, which is paralleled by an increase in prolyl hydroxylase activity. After 6 h recovery from the anoxic stimulus, however, cultures still yield more prolyl hydroxylase than controls, but the effect on hydroxylation of nascent collagen has disappeared. These observations help to dissect the dual role of ascorbate which can stimulate hydroxylation both by increasing the amount of active enzyme and by a cofactor-like role; in addition, these observations may be relevant to wound healing.

Ascorbic Acid↗