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Biomedical subjects

B Lloyd

Publications and source records attributed to B Lloyd.

At least 37 records · Page 2Linked to original sources
PubMed1989

Blood selenium concentrations and glutathione peroxidase activity.

Selenium concentrations in children and teenagers without a metabolic disorder eating normal diets (group 1), and young patients with classical phenylketonuria and milder forms of hyperphenylalaninaemia being treated with a diet low in natural protein (group 2) were investigated. There was a strong correlation between blood selenium concentration and age in children in group 1 up to 10 years of age. Blood selenium concentrations and glutathione peroxidase activities were significantly lower in the patients who were receiving diets containing reduced amounts of natural protein, and the differences were more than would be expected for age. When the concentrations of selenium in blood from groups 1 and 2 were compared with glutathione peroxidase activity, a strong association was found when blood selenium concentrations were below 1.26 mumol/l. Reduction in glutathione peroxidase activity may be harmful in the long term, and the addition of selenium to therapeutic diets is recommended.

Adolescent↗
PubMed1989

The effect of supplementation with selenium and vitamin E in psoriasis.

Since reduced concentrations of selenium in whole blood, plasma and white cells had previously been observed in psoriasis, 69 patients were supplemented daily with either 600 micrograms of selenium-enriched yeast, 600 micrograms of selenium-enriched yeast plus 600 IU of vitamin E or a placebo for 12 weeks. Before supplementation, the patients' mean concentrations of selenium in whole blood and plasma were reduced compared with those of matched healthy controls but their red cell glutathione peroxidase (GSH-Px) activity was normal. After 12 weeks supplementation the patients' mean whole blood, plasma and platelet selenium concentrations, platelet GSH-Px activity and plasma vitamin E concentration had risen significantly from the baseline values but their mean skin selenium concentration and red cell GSH-Px activity remained unchanged. The mean white cell selenium concentration rose only in the group receiving selenium alone. Neither supplementation regimen reduced the severity of psoriasis or produced side-effects. The increase in platelet GSH-Px activity suggests that the supplements were bioavailable and that the patients' selenium status may have been reduced prior to supplementation. The failure of the selenium content of the skin to increase may explain why the patients' psoriasis remained unchanged during supplementation.

Adult↗
PubMed1989

The effect on atopic dermatitis of supplementation with selenium and vitamin E.

Reduced concentrations of selenium in whole blood, plasma and white cells and reduced activity of selenium-dependent glutathione peroxidase in red cells have been found in atopic dermatitis. To determine the effect of selenium supplementation on this disease, the normal daily diet of 60 adults with atopic dermatitis was supplemented with selenium-enriched yeast for 12 weeks in a randomised double-blind study. Group 1 took 600 micrograms of selenium alone, Group 2 600 micrograms of selenium plus 600 IU of vitamin E and Group 3 a placebo. After 12 weeks, there was a significant increase in the concentration of selenium in whole blood and the activity of selenium dependent glutathione peroxidase in platelets in Groups 1 and 2 and the concentration of vitamin E in plasma in Group 2. There was no significant difference between the three Groups in the severity of the eczema or the concentration of selenium either before or after the 12 weeks of supplementation. The results suggest that although selenium-enriched yeast supplement was absorbed and bioavailable it does not enter the skin or produces a worthwhile improvement in atopic dermatitis.

Adult↗
PubMed1988

A note on the effects of age and gender on children's social behaviour.

Observations of 40 3-4-year-olds' social behaviour in dyadic play show that total social behaviour towards opposite gender partners increases across this age range, while remaining constant for same gender partners. This finding partially replicates the results of an earlier study (Lloyd & Smith, 1986). In addition, analyses of three subcategories of social behaviour (prosocial, assertive and withdrawal) also yield partial replications. It is suggested that variations in procedure may account for differences between the two studies.

Age Factors↗
PubMed1988

Reduced concentrations of selenium in mild Crohn's disease.

The concentrations of selenium, zinc, and copper were determined in whole blood, plasma, and leucocytes in 20 patients with relatively mild Crohn's disease, nine of whom were being treated with steroids, and compared with those of a control group. There was a significant decrease in the concentration of selenium in the leucocytes as well as in whole blood and plasma in the patients. Steroids seemed to affect only the concentrations of zinc and copper in plasma. The concentrations of copper and zinc in whole blood, plasma, and leucocytes in patients not taking steroids were not significantly different from those of the control group. The observations suggest that those patients with an apparently satisfactory whole body concentration of copper and zinc may still be at risk of a decrease in the body content of selenium.

Adult↗
PubMed1988

Introduction of a porcine growth hormone fusion gene into transgenic pigs promotes growth.

Six transgenic pigs have been produced by microinjecting a human metallothionein promoter/porcine growth hormone gene construct into the pronuclei of fertilized eggs which were transferred to synchronized recipient sows. The resulting transgenic animals contained between 0.5 and 15 copies of the gene construct per cell, and at least one of the animals expressed the introduced gene and grew at an increased rate compared to both transgenic and non-transgenic littermates. Some of the transgenic animals that did not appear to grow at increased rates were found to contain rearranged gene sequences. Two of the transgenic pigs have been shown to pass on the introduced genes to their offspring.

Animals↗
PubMed1988

Skin selenium content measured by hydride generation and atomic absorption spectroscopy.

The concentration of selenium in skin was measured using hydride generation and atomic absorption spectroscopy. The method used in this study was shown to be both accurate and precise, with mean recoveries of 92%-98% of added selenium and a within run relative standard deviation of better than 7% at a selenium concentration of less than 12 nmol/g dry tissue. The method is suitable for rapid analysis of large numbers of samples.

Biopsy↗
PubMed1987

Reduced plasma and white blood cell selenium levels in haemodialysis patients.

Selenium concentrations have been measured in plasma and in blood leucocytes from 29 haemodialysis patients and from 25 healthy men. The selenium contents of the plasma and white blood cells of the dialysis patients were significantly reduced (p less than 0.001). Selenium deficiency in humans results in a congestive cardiomyopathy and is associated with increased risks of accelerated atherosclerosis and cancer. Each of these is found with abnormal frequency in haemodialysis patients.

Adult↗
PubMed1986

Aminoterminal procollagen III peptide elevation in alcoholics who are selenium and vitamin E deficient.

Serum aminoterminal procollagen III peptide (PIIIP) was measured in 36 alcoholic subjects. There was a significant elevation of PIIIP in subjects with proven liver disease (median 17.5 ng/ml, n = 24) compared to those without liver disease (median 4.7 ng/ml, n = 12). Those subjects with raised serum transaminase values (AST) had elevated PIIIP values (median 13.7 ng/ml, n = 22) compared to those with normal transaminase values (median 3.7 ng/ml, n = 14). In those alcoholic subjects who were deficient in both selenium and vitamin E there was a significant elevation (p less than 0.01) of PIIIP values (median 26.4 ng/ml, n = 7) compared to subjects with normal levels (median 7 ng/ml, n = 11). Subjects deficient in selenium alone had PIIIP values in an intermediate range. Selenium and vitamin E, as important free radical scavengers, may protect the liver in alcoholic subjects from oxidative damage leading to hepatic fibrosis.

Aspartate Aminotransferases↗
PubMed1986

Depressed selenium and vitamin E levels in an alcoholic population. Possible relationship to hepatic injury through increased lipid peroxidation.

Serum selenium and vitamin E levels have been measured in subjects with established alcoholic liver disease, in alcoholics within the community, and in appropriate controls. Both serum selenium and vitamin E levels were shown to be significantly depressed (P less than 0.01) in the alcoholic study groups and serum selenium was more markedly depressed in subjects with established liver disease (controls, serum selenium 108 +/- 13 micrograms/liter, vitamin E 27.6 +/- 7.2 mumol/liter; community alcoholics, serum selenium 94 +/- 19 micrograms/liter, vitamin E 15.3 +/- 3.4 mumol/liter; alcoholic liver disease, serum selenium 78 +/- 15 micrograms/liter, vitamin E 14.7 +/- 5.6 mumol/liter). Depressed serum selenium levels correlated closely with poor nutritional status (r = 0.91). There were no changes in serum glutathione peroxidase activity. Liver disease activity, as judged by transaminase (AST), was more markedly abnormal in subjects with combined vitamin E and selenium deficiency compared to those with normal levels or isolated deficiencies (no deficiency, AST 48 +/- 19 units, combined deficiency, AST 75 +/- 21 units, P less than 0.03). Serum lipid peroxides were elevated in those with combined deficiency and the values correlated significantly with serum transaminases (r = 0.40, P = 0.03).

Adult↗
PubMed1986

The significance of social identities.

Common-sense meanings of the 'individual' and the 'social' are examined emphasizing the fallacy of viewing them as denoting separate entities given in nature. The concept of social representations is used to explain the construction of these categories in terms of the particular systems of values, ideas and practices of different societies. The concept of social identity marks the individual-social interface interpreted as the construction of individuals in relation to the social representations of significant groups in their society. The earliest constructions of a social identity are traced in the domain of gender because this is a ubiquitous feature of social life, involving the differentiation of only two groups; they are obligatory and use physical differences to provide the signifiers in a semiotic system of social representations. Empirical evidence is reviewed showing that the development of a social gender identity is a complex process and involves many aspects of children's activity slowly coming to be regulated by the particular social representation of gender dominant in their society.

Child↗
PubMed1986

Dihydropteridine reductase activity in dried blood spots: effects of aging and senile dementia of the Alzheimer type.

Dihydropteridine reductase (EC 1.6.99.7) (DHPR) activity was measured in blood spots from 50 neonates, 52 healthy adults aged 30-62 years, and 21 elderly controls aged 67-97 years, as well as 32 demented patients of whom 25 had senile dementia of the Alzheimer type. Enzyme activity was stable for seven days at 4 degrees C and for at least 14 days at -20 degrees C. No important difference was found between the DHPR activity of venous and capillary blood. DHPR activity was considerably lower in the healthy adult group compared with neonates and the elderly group, and there was no sex difference at any age. The erythrocyte DHPR activity of patients with senile dementia of the Alzheimer type was similar to that of elderly controls. This result differs from that previously reported for leucocytes.

Adult↗
PubMed1984

Body content of selenium in coeliac disease.

Concentrations of selenium in whole blood, plasma, and leucocytes were determined in 16 patients with coeliac disease confirmed by biopsy and 32 controls. All the patients were clinically well and receiving gluten free diets. The concentrations of selenium were significantly lower in the leucocytes, blood, and plasma of patients compared with controls, probably indicating a decrease in the body content of selenium. A high incidence of malignancy in coeliac disease has been reported. As a protective role for selenium against cancer has been postulated, the importance of this unexpected observation of lowered tissue concentrations of selenium requires further investigation.

Adult↗
PubMed1984

Selenium and vitamin E in relation to risk factors for coronary heart disease.

Fasting blood samples taken from 116 apparently healthy men aged 30-50 years were assayed for selenium, glutathione peroxidase activity, vitamin E, cadmium, lead, glucose, lipids, and albumin. Blood pressure was measured in each subject, and details of height, weight, smoking habits, and alcohol consumption were recorded. Multivariate analysis of the data showed that the decrease in blood and serum concentrations of selenium and the increase in whole blood cadmium concentrations in the cigarette smokers was independent of alcohol consumption. There was no correlation between blood selenium concentrations or glutathione peroxidase activities and the risk factors for cardiovascular disease. Neither alcohol consumption nor smoking had an effect on the vitamin E concentrations. There was a strong association, however, between vitamin E and serum lipid concentrations, although the increase in triglyceride concentrations in the smokers was not matched by a comparable increase in vitamin E. The possible role of selenium in the aetiology of heart disease remains unresolved.

Adult↗
PubMed1983

Effect of smoking, alcohol, and other factors on the selenium status of a healthy population.

In a study of selenium status in 391 apparently healthy subjects resident in the south of England statistical examination of the data showed a significant effect with regard to age, smoking, alcohol, and oral contraceptives. The most important of these factors seems to be a combination of alcohol and smoking habits in men over 30. Reference ranges have been established for glutathione peroxidase activities and the concentrations of selenium in whole blood plasma and erythrocytes.

Adolescent↗