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Biomedical subjects

C J Bates

Publications and source records attributed to C J Bates.

At least 91 records · Page 5Linked to original sources
PubMed1993

The efficacy of a hospital dry cleaning cycle in disinfecting material contaminated with bacteria and viruses.

It is not known how efficiently a standard dry cleaning cycle can kill bacteria or viruses. In-situ experiments were carried out to determine the cidal activity of such a cycle using perchloroethylene solvent against five clinical bacterial isolates and a DNA bacteriophage. Viable counts of bacteria recovered from material after dry cleaning were reduced by 3-8 logs, with up to 10(3) colony forming units (cfu) surviving per strip. Numbers of bacteriophage were only reduced by 10-100 fold. The resistance of the bacteriophage to solvent and heat (60 degrees C) was compared with that of polio and herpes simplex viruses in vitro. Polio virus and bacteriophage, but not herpes simplex virus, survived exposure to perchloroethylene at room temperature for 40 min. Dry cleaning with perchloroethylene is not bactericidal and is particularly poorly virucidal for non-enveloped viruses.

Bacteria↗
PubMed1993

A trial of zinc supplementation in young rural Gambian children.

The present study tested the hypothesis that inadequate Zn intake might be responsible for failure to thrive and impaired catch-up growth in young rural Gambian children, and that Zn supplements might be beneficial. Gambian children might be deprived of Zn because of its poor availability from their predominantly plant-based diet. Rural Gambian children (110; fifty boys, sixty girls) aged between 0.57 and 2.30 years were divided into two matched groups, one to receive 70 mg Zn twice weekly for 1.25 years, and the other a placebo. Growth and mid-upper-arm circumference were measured at weekly intervals throughout the study and illnesses were monitored. Capillary blood and urine samples were collected at 0, 2 and 8 weeks. Body weights and arm circumferences showed a linear increase, plus a seasonal effect (rainy season faltering). For body weight there was no significant overall effect of the supplement. For arm circumference, a very small (2%) but significant (P < 0.01) difference favoured the supplemented group. Plasma thymulin was much lower at the first clinic than at the second and third clinics, and in vitro Zn stimulation was greater at the first clinic. There was, however, no effect of Zn in vivo. Likewise, Zn did not significantly benefit T-cell numbers or ratios, secretory IgA in urine, circulating hormone levels or biochemical indices of Zn status. One index of intestinal permeability, i.e. lactulose: creatinine, was improved (P < 0.02) by the supplement, but the lactulose: mannitol value was not; this requires further investigation. Dietary Zn deficiency is, thus, unlikely to be of major overall importance for rural Gambian children's ability to thrive, and blanket Zn supplementation is not justified. There may, however, be vulnerable sub-groups who would benefit from Zn supplements.

Anthropometry↗
PubMed1993

Nutritional efficacy of a fortified weaning rusk in a rural area near Beijing.

A micronutrient-fortified rusk for weanling children was tested in a rural area near Beijing. Two hundred twenty-six children aged 6-13 mo were randomly assigned by village to either a micronutrient-fortified or an unfortified rusk, daily for 3 mo. The fortified rusk contained extra zinc; iron; calcium; vitamins A, D, and B-12; thiamin, riboflavin, niacin, and folic acid. Infants receiving the fortified rusk exhibited no decline in hemoglobin concentrations during the study whereas those receiving the unfortified rusk exhibited a significant decline. Improvements were also seen in erythrocyte porphyrin, plasma vitamin A, and riboflavin status, but these improvements were seen in both of the groups. Micronutrient fortification was probably beneficial for iron status and the fortified rusk promises to be an effective vehicle for supplementation.

China↗
PubMed1992

Plasma folate levels in preterm infants, with and without a 1 mg daily folate supplement.

One hundred and four preterm infants were studied during the first few months of life in the Special Care Baby Unit of Addenbrooke's Hospital, Cambridge, United Kingdom. Previously, it had been the daily practice within the Unit to give a 1 mg oral supplement of folate (in the form of pteroylglutamic acid), once the infants had commenced full enteral feeding. At least one blood sample was obtained from 70 infants before oral folate supplementation was started. In these, the plasma folate levels fell progressively from a median value of 45 micrograms/l to a median of 12 micrograms/l, by the 2nd-3rd week of life. Once started on the oral supplement, 83 of the infants provided at least one blood sample. The plasma folate level of these infants rose immediately to a median value of 300 micrograms/l and a maximum of 1000 micrograms/l. Within individuals, these plasma folate levels decreased progressively following the introduction of the supplement, despite continuing daily supplementation. In a typical baby this decrease appeared to be explained by an increase in body-size, i.e. dilution of the folate into a larger pool. The implications of this level of supplementation are discussed, and in the light of our observations we suggest that daily supplementation in the range, 0.05-0.2 mg folate may be preferable for well preterm infants.

Dose-Response Relationship, Drug↗
PubMed1992

High folate intakes related to zinc status in preterm infants.

The former practice of giving 1 mg (2.27 mumoles) oral folic acid daily to premature infants receiving enteral feeds was assessed with respect to zinc status in Cambridge, United Kingdom. A group of 60 preterm infants, 80% of whom were receiving 1 mg oral folic acid daily, were studied for up to the first 16 weeks of life. Plasma folate and plasma zinc were measured for each subject. A significant inverse relationship was found between the maximum attained serum folate level and the minimum attained serum zinc level, (t = 5.0, 58 df, P less than 0.0001). This remained significant after corrections had been made for gestational age at birth, fetal growth retardation, birth weight, sex, diet, assisted ventilation and length of time to full enteral feeding. The hypothesis that very high folate intakes may adversely affect serum zinc levels and, by inference, zinc status in preterm infants could not be rejected. Caution is therefore advised when prescribing such very high folate doses daily for small preterm infants.

Dose-Response Relationship, Drug↗
PubMed1992

Effect of vitamin C on sorbitol in the lens of guinea-pigs made diabetic with streptozotocin.

Marginally vitamin C-deficient guinea-pigs treated with the diabetogenic agent streptozotocin were compared with those liberally supplied with vitamin C, for functional indices of vitamin C status, particularly in the eye lens. Weanling male Dunkin-Hartley guinea-pigs were fed on diets with 0.1 g vitamin C/kg (marginally deficient), or 5 g/kg (liberally supplied), and some received intraperitoneal streptozotocin (two doses of 150 mg/kg body-weight). About half the streptozotocin-treated animals had high urinary glucose following an oral glucose dose; these animals also grew more slowly than the others. At 4 months after streptozotocin the animals were killed for measurement of tissue vitamin C, glucose and sorbitol. Streptozotocin moderately increased the concentration of glucose in plasma, lens and aqueous humour. Lens sorbitol levels increased only in the group exposed to streptozotocin plus marginal vitamin C. There was a significant (P less than 0.02) positive correlation between urinary glucose and lens sorbitol levels overall. Liberal vitamin C intake may thus counteract the effect of streptozotocin diabetes on lens sorbitol, suggesting a new function of vitamin C, possibly related to cataractogenesis and to the biochemical lesions associated with diabetes.

Adenosine Triphosphate↗
PubMed1992

A study of whole-body isotope dilution of [14C]ascorbic acid in guinea-pigs with graded ascorbate intakes.

The purpose of the present study was first to assess the extent to which unlabelled ascorbate in the diet of guinea-pigs can exchange with labelled ascorbate within their organs when the dietary intake is varied over a wide range, and second to determine whether the retention of label might be used to assess either the amount of ascorbate intake or its biological availability where these are not known. The retention of [14C]ascorbate in the body and in various organs of guinea-pigs were, therefore, measured following a 13 d period of graded dietary intakes of ascorbate. It was found first, that the amount of label retained in each of the organs, 13 d after the initial dose of labelled ascorbate, was much more closely related to the amount of ascorbate intake after labelling than to the intake (and tissue ascorbate levels) before and at the time of labelling. Second, most of the individual internal organs exhibited a constant relationship between the specific activity at 13 d and the dietary intake, except for brain which was flushed to a smaller extent. Third, in agreement with several previous studies a high proportion of the radioactive label in the tissues was found to be still present in ascorbate. The specific activity of column-purified ascorbate was very similar to the estimated specific activity in the crude extract, which implies that it may be possible to estimate specific activities (or stable isotope enrichments) at certain sites without rigorous isolation procedures. Fourth, the amount of radioactivity appearing in the urine 2 d before killing the animals was correlated with the amount of ascorbate intake and with tissue specific activities, suggesting that intakes (or bioavailability) might be predicted from the patterns of label-appearance in the urine.

Animals↗
PubMed1992

Incorporation of [3H]proline into collagen and other proteins in rats fed diets with various zinc concentrations.

Incorporation of labeled proline into liver and skin proteins of weanling rats was studied during zinc restriction. Reduced incorporation of labeled proline into skin proteins including collagen hydroxyproline and an increase in its incorporation into liver and plasma proteins was observed with 0 or 0.046 mumol zinc/g diet, compared with 0.092, 0.153 or 0.306 mumol/g diet. Food (energy) restriction was then compared with zinc restriction, during recovery from protein restriction. A shift in proline incorporation from skin protein and skin collagen hydroxyproline, towards liver and plasma proteins, was closely correlated with body weight gain, whether it was limited by zinc restriction or by energy restriction. This diversion of label from skin to liver and plasma is probably mediated through mechanisms that limit growth during food restriction. Proline-incorporation patterns during zinc or energy restriction are clearly different from those of vitamin-C deficiency in guinea pigs.

Animals↗
PubMed1991

Glutathione and related indices in rat lenses, liver and red cells during riboflavin deficiency and its correction.

Biochemical changes in lenses and at other sites in adult rats were investigated during the induction and correction of riboflavin deficiency. Riboflavin deficient (D), 1-day-repleted (R1), 2-days-repleted (R2), 16-days-repleted (R3), food-restricted, weight-matched controls (CFR) and ad libitum-fed controls (CAL) were compared. Activation coefficients of erythrocyte and lens glutathione reductase, which became abnormal in the deficient (D) animals, were corrected to varying extents in the repleted (R) groups. Hepatic flavin concentrations were lowered in the groups with raised glutathione. Inter-group differences in hepatic glutathione concentrations were not simply related to tissue flavin depletion or its reversal, but were complicated by changes in liver: body-weight ratios. Inter-group differences in lenticular glutathione levels were very small. In both liver and lens, sorbitol concentrations were lowest in group R3 and highest in groups D, R1 and R2. Lens ascorbate levels and the lens enzymes, aldose reductase, sorbitol dehydrogenase, glutathione peroxidase and superoxide dismutase, were not significantly affected by diet. Thiobarbituric acid-reactive substances were increased in riboflavin-deficient rat lenses but were lowered in riboflavin-deficient plasma samples. The results suggest overall that while riboflavin deficiency may affect certain biochemical indices, such as sorbitol and thiobarbituric-reactive substances, in the lens and other tissues, these changes are not the result of lowered glutathione levels. They also clearly demonstrate the importance of inanition as a confounding factor in the interpretation of changes resulting from riboflavin deficiency in experimental animals.

Animals↗
PubMed1990

Liberation of 14CO2 from [14C]adipic acid and [14C]octanoic acid by adult rats during riboflavin deficiency and its reversal.

The purpose of the present study was to test the hypothesis that the already well-established mitochondrial lesion in fatty acid oxidation in riboflavin-deficient experimental animals, might be accompanied by an alteration in vivo in the kinetics of oxidation of labelled adipic acid. This dicarboxylic acid was chosen for testing as a metabolic probe because a block in its oxidation was already apparent from urine analysis of riboflavin-deficient animals, whereas the oxidation of medium- or long-chain monocarboxylic acids seemed to be little affected by deficiency in vivo. Female adult Norwegian hooded rats fed on purified diets containing either 15 mg riboflavin/kg diet (controls) or about 0.4 mg/kg (riboflavin-deficient) received an intragastric dose of either [1,6-14C]adipic acid or [1-14C]octanoic acid. Expired carbon dioxide was then collected in an alkaline trap over 3 h, for determination of radioactivity. This test was repeated at intervals for up to 2 weeks following riboflavin repletion of the deficient animals, and in riboflavin-dosed controls. Whereas the rate and extent of [14C]octanoic acid oxidation was not significantly affected by the deficiency or repletion, the extent of [14C]adipic acid oxidation was markedly and significantly increased during repletion of the deficient animals. The time-course indicated a temporary overshoot, followed by a slow return to the control values over 1-2 weeks. Adipate oxidation was also much less affected by a preceding period of overnight starvation, than was octanoate oxidation. Thus, adipic acid (or a related metabolic probe) may have appropriate properties for the design of a functional test of fatty acid oxidation efficiency, during riboflavin deficiency or allied metabolic conditions in human subjects.

Adipates↗
PubMed1990

Zinc in breast milk during prolonged lactation: comparison between the UK and the Gambia.

A total of 580 breast milk samples were collected from 56 lactating women living in a rural village community in The Gambia, West Africa, and 92 samples were obtained from 57 lactating women living in Cambridge, England. Total zinc content of each sample was measured by atomic absorption spectrometry, and pooled samples of the Gambian breast milks, representing successive periods of lactation, were fractionated into fat, whey and insoluble casein fractions, to examine zinc distribution. The two sets of milks both exhibited a dramatic decline in total zinc concentrations with increasing duration of lactation, in common with previous studies. However, the UK milks unexpectedly had lower zinc contents at all stages than the Gambian milks. Milk zinc levels were not significantly related to either maternal age or parity in the Gambian women. The proportion of zinc found in the sedimentable fraction remained nearly constant with increasing duration of lactation, but the proportion found in the fat fraction increased and the proportion in the whey fraction declined. These observations are potentially relevant for estimations of milk zinc availability and the fulfillment of zinc requirements by infants, and hence for infant feeding practices.

Adolescent↗
PubMed1989

Vitamins, iron, and physical work.

Combined marginal deficiencies of iron, vitamin C, and B-group vitamins are widespread in developing countries. An understanding of the functional implications poses a continuing challenge, both for the development of new techniques of investigation and for the design of effective intervention programmes. Practical intervention in developing countries also needs to take account of the interactions of micronutrient status and disease susceptibility. It is becoming clear that combined deficiencies of certain vitamins, or of iron and vitamins, although less severe than those causing the lesions of classic clinical deficiency, can seriously reduce work performance. Riboflavin, particularly, has a special relation with iron economy.

Adolescent↗
PubMed1989

Riboflavin deficiency, metabolic rate and brown adipose tissue function in sucking and weanling rats.

1. The effects of riboflavin deficiency on growth, whole-body oxygen consumption, cytochrome c oxidase (EC 1.9.3.1) activity and GDP-binding capacity of brown adipose tissue were measured in three groups of rats: sucking pups, weanling rats, and dams. Control groups were weight-matched, pair-fed or fed ad lib. 2. Riboflavin deficiency reduced growth rate and increased the activation coefficient of erythrocyte glutathione reductase (NAD(P)H) (EC 1.6.4.2), as predicted. In sucking pups it also reduced whole-body O2 consumption per unit body-weight, especially after noradrenaline stimulation. In weanling rats, however, it increased O2 consumption both before and after noradrenaline stimulation. 3. Cytochrome c oxidase (EC 1.9.9.1) activity of brown adipose tissue was not consistently affected by riboflavin deficiency. Binding of [3H]GDP to the mitochondria was increased in the deficient weanling rats. 4. Weanling rats therefore, seemed better able to withstand the effects of severe depletion. Their reduced growth and increased non-shivering thermogenesis helped to counteract the unfavourable ratio of riboflavin:other tissue-building materials. The relevance for thermoregulation in riboflavin-deficient children is discussed.

Adipose Tissue, Brown↗