Biomedical subjects
C J Bates
Publications and source records attributed to C J Bates.
Bioavailability of riboflavin.
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Effect of acyclovir and prednisolone on the serological response in herpes zoster.
The serological response of patients with acute herpes zoster was studied to determine whether a diagnosis could be made on a single serum sample, and whether this response was modified by treatment with antiviral and/or steroid therapy. The patients received one of four regimes of acyclovir and prednisolone, Varicella zoster virus (VZV) IgG, IgM, and IgA responses were measured by commercial and in-house enzyme immunoassays (EIA) using serum samples taken at days 0, 7, and 21 after entry into the study. Samples were also tested for IgM to Epstein-Barr virus (EBV) viral capsid antigen (VCA), and cytomegalovirus (CMV) IgM and for herpes simplex virus (HSV) antibodies by the complement fixation test (CFT). Analysis was carried out on data from 71 patients. VZV IgM was detected in 72%, VZV IgA in 78%, and either VZV IgM or IgA in 88% of patients tested, at some time during the 3-week study period. The optimal time to detect either class of antibody was approximately 1 week after the onset of the vesicular rash, when 85% of patients had one or both classes of acute phase antibody in their serum. There was no evidence of cross reaction with EBV, CMV, or HSV antibodies. Neither treatment with prednisolone nor the length of therapy with acyclovir affected significantly the VZV IgM or IgA responses. Therefore it is possible to make a serological diagnosis of herpes zoster on a single sample, optimally 1 week after the onset of the rash, in patients treated with acyclovir alone or with acyclovir and steroids.
Measurement of ascorbic acid kinetics in man using stable isotopes and gas chromatography/mass spectrometry.
The feasibility of studying ascorbic acid kinetics in man using stable isotope-labelled tracers and gas chromatographic (GC) separation followed by mass spectrometric (MS) quantitation was assessed. Preliminary studies with 13C-labelled material showed that although better precision at low levels could be achieved using the GC/combustion/MS technique, consideration of likely enrichments in a human study made the simpler GC/MS method just as suitable. On this basis, a small pilot study of the kinetics in man was carried out. The enrichment of the ascorbic acid in plasma was measured for a 24 h period after oral administration of 13C-labelled material. The results were fitted to a simple three-compartment model and rate constants and pool sizes were deduced. The results obtained are comparable to those obtained in other published studies, from which we conclude that the technique may be useful as a non-invasive method for the assessment of nutritional status in a variety of populations.
Biochemical evidence of thiamine depletion during the Cuban neuropathy epidemic, 1992-1993.
During an epidemic outbreak of neuropathy in Cuba during 1992-1993, blood and urine samples were collected from 107 persons with confirmed neuropathy, from 106 control subjects without clinical abnormality who were broadly matched with the affected persons by age and domicile, and from 537 unmatched subjects, also free from clinical abnormality. The unmatched subjects lived in two locations in Cuba; at each location they were drawn from two age ranges: 11-15-y-old secondary school students and 16-64-y-old adults. Measurements of urinary thiamine and blood transketolase and its activation with thiamine pyrophosphate were made. For the neuropathy subjects, these measurements were repeated after 3 wk of rehabilitation. All groups showed biochemical evidence of thiamine depletion affecting 30-70% of their members, which is a high prevalence. Severity of biochemical depletion was, however, no greater in the neuropathy subjects than in the control subjects (P > 0.05). However, it was greater in Pinar del Rio, where the incidence of disease was higher, than in the city of Havana, where less disease was seen. Although the majority of the affected subjects responded biochemically to a daily oral multivitamin supplement containing thiamine (P < 0.001), in some cases normal biochemical status was not achieved even after 3 wk of intensive treatment. In the affected group, thiamine status was inversely correlated with the amount of alcohol consumed (P = 0.007). Thiamine status at the outset was correlated with clinical outcome after treatment. Although neither thiamine depletion nor alcohol abuse were likely to have been the sole cause of the neuropathy epidemic, they may have been contributory factors. Thiamine supplementation or food fortification may therefore be necessary in Cuba.
Quantitation of vitamin E and a carotenoid pigment in cataractous human lenses, and the effect of a dietary supplement.
The quantitation of tocopherols and carotenoids in lipid extracts of cataractous human lenses was performed in parallel with those of matched samples of plasma, which was also analysed at the same time. Alpha-tocopherol in cataractous lenses from elderly human subjects was present at 4.4 mumoles/kg wet weight, much less than the mean of 33 mumoles/l in plasma from these subjects. The mean ratio of alpha- and gamma-tocopherols was 3.5 in the lenses, and 11.3 in plasma. Lens extracts contained no detectable alpha- or beta-carotene, lycopene, or beta-cryptoxanthin. However, all the lens extracts contained a pigment with the retention time and spectrum of lutein and zeaxanthin. Using the molar extinction coefficient of lutein this was present at ca. 0.03 microM, compared with 0.2 microM in plasma. Seven patients with bilateral cataracts had one of their cataractous lenses removed and analysed, and were then given either an oral placebo, or an oral supplement of ascorbate, alpha-tocopherol and beta-carotene. Three months later, the second cataractous lens, and a blood sample, were analysed. Three of the seven had received the active supplement, as confirmed by substantially raised blood levels of alpha-tocopherol and beta-carotene, and raised aqueous humour levels of vitamin C. However, lens tocopherol levels remained unchanged, and no beta-carotene could be detected in the lenses after supplementation. This preliminary evidence needs to be confirmed in larger studies.
Survival of Salmonella species in eggs poached using a microwave oven.
The use of microwave ovens is becoming increasingly popular, but there is little data on the bactericidal effect of this mode of cooking. Following a family outbreak of gastroenteritis due to Salmonella enteritidis PT4, where eggs poached in a microwave oven were the suspected source, we investigated the survival of Salmonella spp. in artificially contaminated eggs cooked in a microwave oven. The survival of six serotypes of Salmonella at various inocula were studied, after cooking the eggs using two recognized poaching methods. Salmonellae were readily recovered after cooking if the yolk was still soft, whichever serotype, inoculum or cooking method was used. The survival of organisms was related to the number of organisms present in the raw eggs. The advice regarding eating lightly cooked eggs should be the same whether microwave or more conventional cooking techniques are used.
Documentation of blood culture results.
AIMS: To evaluate the adequacy of documentation of blood culture results in patients' medical notes. METHODS: A pro-forma was completed following review of medical notes at 24 and 48 hours after a blood culture had been reported as positive. The study was performed on blood cultures received at the Department of Microbiology, Royal Hallamshire Hospital, Sheffield, from two local hospitals. Two periods were studied: (A) May to June 1993 and (B) September to October 1993. RESULTS: There were 43 results studied in period A and 79 in period B, giving a total of 122 results studied. Overall, 72 (59%) of 122 results were recorded in the medical notes at 24 hours. Of those results deemed highly significant, 40 (63%) of 63 were recorded. There was no significant difference in the documentation of results if the result was given personally or via the telephone. Nor was there any difference in documentation between different medical grades. Throughout the study there were six inaccurate records. The cumulative documentation over 48 hours of positive results was 54 (86%) of 63 of highly significant, 27 (69%) of 39 of uncertain significance, and 11 (55%) of 20 probable contaminant results. CONCLUSIONS: Documentation of blood culture results is currently suboptimal.
Biochemical indices and neuromuscular function tests in rural Gambian schoolchildren given a riboflavin, or multivitamin plus iron, supplement.
Ninety preselected children, aged between 8 and 14 years, living in two rural West African (Gambian) villages, were randomly divided into three groups, matched for age and sex. One group received a placebo (lactose) tablet, one received riboflavin (5 mg) on 5 d every week, which was sufficient to correct an endemic riboflavin deficiency, and one received a multivitamin supplement (Protovit; Hoffmann La Roche), on 5 d every week, together with FeSO4 (200 mg) once weekly, and the supplements were given for 1 year. Neuromuscular tests, including arm tremor and manipulative skills, were performed on three occasions: once just before the introduction of the supplements; again 6 weeks after commencing the supplements; and again 1 year later. Venous blood samples were collected at the same time as the first two sets of neuromuscular tests. These samples were used for haematology and nutrient status indices: plasma ferritin, ascorbic acid, cyanocobalamin and pyridoxal phosphate, and erythrocyte tests for folate status, for riboflavin status (erythrocyte glutathione reductase activation coefficient) and thiamine status (erythrocyte transketolase activation coefficient). The riboflavin in both supplements achieved a clear-cut response in biochemical status, which was dose-dependent. The pyridoxine, ascorbic acid and Fe components of the multivitamin also affected the associated biochemical indices. Although overall the arm tremor and related neuromuscular function tests did not respond significantly to the supplements, significant improvement was seen in the boys for the arm-tremor test in both the supplemented groups.
Ascorbic acid deficiency in guinea pigs: contrasting effects of tissue ascorbic acid depletion and of associated inanition on status indices related to collagen and vitamin D.
To investigate the sensitivity of guinea pig tissues to ascorbic acid depletion, as distinct from inanition, young male guinea pigs were maintained with either ascorbic acid restriction or total diet restriction for 8 weeks. One group (A) received no ascorbic acid for 3 weeks, then 0.5 mg/d for 5 weeks; one group (B) was weight-matched by restricted food intake to the first group; a third (marginally deficient) group (C) received 1 mg ascorbic acid/d throughout; a fourth was weight-matched to this group (D); and a fifth group received the control diet ad lib. (E). Both of the groups with restricted ascorbic acid intakes (A and C) developed very low tissue ascorbic acid contents, but only the first group (severely deficient group A) also exhibited a severely reduced growth rate. This group also exhibited reduced femur calcium and hydroxyproline contents and reduced skin hydroxyproline content. These changes were not seen in the corresponding weight-matched group (B). Neither plasma alkaline phosphatase (EC 3.1.3.1) activity, nor a variety of indices of vitamin D status exhibited changes which could be attributed specifically to reduced ascorbic acid intake and hence to lowered tissue ascorbic acid content. It is concluded that low tissue ascorbic acid levels in guinea pigs clearly alter the connective tissue composition of growing femur and skin, but do not necessarily produce a major, specific effect on vitamin D status. Moreover, the control of inanition is crucial to permit interpretation of the changes in metabolism that are caused by ascorbic acid deficiency.
Prosthetic hip joint infection due to Campylobacter fetus.
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Does vitamin C intake influence the rate of tyrosine catabolism in premature babies?
A study was conducted to investigate the relationship between vitamin C intake and the rate of tyrosine catabolism in premature babies. A 13C tyrosine breath test was developed for the measurement of tyrosine catabolism. Premature babies were randomly allocated to receive a daily intake of vitamin C which ranged from 8 to 100 mg/kg body weight, for 5 days. Tyrosine catabolism was measured at the beginning and the end of this period. Daily intakes of vitamin C of 20 mg/kg or more elicited a greater increase in tyrosine catabolism over 5 days than 8 mg/kg/day. The magnitude of the difference, in terms of percentage of tyrosine metabolised, was, however, small and of doubtful biological significance. Vitamin C intakes above 20 mg/kg/day had no further measurable effect on the catabolism of tyrosine.
Plasma vitamin C assays: a European experience. EC FLAIR Concerted Action No. 10: Micronutrient Measurement, Absorption and Status.
Assay procedures for plasma concentrations of vitamin C, and hence for vitamin C status, currently in use in European population-surveillance laboratories and elsewhere, are based on a wide range of disparate techniques and reactions. The problem of achieving harmonisation between these techniques, and between laboratories, is further complicated by the instability of the vitamin, and the existence of several chemical forms. In the course of a European Community FLAIR programme, of inter-laboratory assay method comparisons for micronutrients, nine European laboratories performed either one or two coordinated ring tests, and some coordinated checks on in-house plasma samples, spiked with a low level of ascorbic acid. The principal conclusion was that good agreement was difficult to obtain, between laboratories and between methods, at plasma vitamin C concentrations close to the cut-off for biochemical deficiency, i.e. ca. 11 microM vitamin C in untreated plasma. By the second ring test, and after the correction of some aberrant results due to malfunctioning apparatus, interlaboratory coefficients of variation of 13-20% were achieved, within the biochemically "normal" range of 36-94 microM. There remains, however, a need for critical within and between-laboratory checks and comparisons, and for new quality control materials, with assigned values.
Seasonal variations in vitamins A, C, riboflavin and folate intakes and status of pregnant and lactating women in a rural Gambian community: some possible implications.
OBJECTIVE: To relate measured intake of vitamins A, C, folate and riboflavin to biochemical indicators of nutritional status for these micronutrients, and to examine seasonal variations. SETTING: MRC Dunn Nutrition Unit Field Station, Keneba, The Gambia, which has heavy rainfall in August, and little or no rain between late September and mid-June. Data were collected during 1978-80. SUBJECTS: Pregnant or lactating women in a rural farming community whose diet has been studied throughout the year. RESULTS: Mean daily intake of vitamin C varied from virtually nil during the rainy season to about 100 mg/d in May, while plasma ascorbate ranged from 0.2 to 1.2 mg/dl, and breast-milk ascorbate from 2 to 6 mg/dl, changing synchronously with changing intake. Intake of retinol equivalents ranged from 120 micrograms/d in December to 900 micrograms/d in June, and plasma carotenoids showed synchronous fluctuation from 60 to 180 micrograms/dl, whereas plasma retinol was virtually unchanged throughout the year at 30 micrograms/dl. Intake of riboflavin was very low throughout the year, but erythrocyte glutathione reductase activation coefficient ranged from a minimum of 1.5 in July to a maximum of 1.9 between December and March. Obstetric outcome also exhibited seasonal variation with lowest birthweights during the rainy season. Intakes of food energy are assumed to be the major dietary influence on birthweight, but micronutrient intakes and status may have additional effects, and seasonality clearly affects ascorbate intakes by suckling infants. CONCLUSIONS: In countries such as The Gambia seasonality is a major determinant of micronutrient status. However, dietary intake is not the only factor which determines micronutrient status: thus there are seasonal fluctuations in riboflavin status which, for example, may relate to changes in the balance between energy intake and output, rather than to seasonal changes in riboflavin intake.
Adequacy of dietary mineral supply for human bone growth and mineralisation.
The evidence on the relationship between dietary mineral supply and bone development in children has been extensively reviewed. Data from children and primates suggest that overt deficiencies of Ca, P and Zn are likely to produce rickets and growth retardation, while the effects of Mg deficiency on human bone are unknown. The manifestations of marginal deficiencies are little understood. The biological needs for Ca, P, Mg and Zn in childhood have been calculated based on mineral deposition rates, using published values for the mineral content of the human body, and on obligatory endogenous losses. As a rough guide, the estimated biological requirements for the Ca, P, Mg and Zn can be taken as 200, 100, 4 and 1 mg/d respectively. A comparison of measured daily intakes of children in developing countries with biological requirements was made. This revealed that P and Mg intakes were many times higher than estimated needs. Ca intakes at all ages were found to be close to the biological requirement for children in many Third World societies, before any allowance for possible poor absorption. Zn intakes approach estimated needs in breast-fed infants, particularly during weaning, but are 4-5 times higher in older children. Poor absorption from phytate-rich diets could affect Zn supply. Supplementation studies indicate that raising Zn intakes can increase height gains in certain vulnerable groups, such as infant and adolescent boys. In conclusion, the evidence suggests that inadequate dietary intakes of Ca and Zn may contribute to linear growth retardation in children of developing countries but more research is needed.
Assay for carotenoid 15,15'-dioxygenase in homogenates of rat intestinal mucosal scrapings and application to normal and vitamin A-deficient rats.
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