We describe enzymic fluorometric methods of automated analysis for glucose, lactate, pyruvate, 3-hydroxybutyrate, glycerol, and alanine in perchloric acid extracts of blood. Unmodified Technicon AutoAnalyzer II apparatus is used. The usual concentrations of all these metabolites can be measured in as little as 0.1 ml of blood from a fasting subject. Within-batch and between-batch coefficients of variation ranged from 0.4 to 4.4% for all metabolites except 3-hydroxybutyrate, for which CV's were higher for low concentrations. Analytical recovery of added metabolites ranged from 92 to 98%. Glucose, lactate, alanine, and 3-hydroxybutyrate are stable in perchloric acid extracts for at least 13 days at room temperature, and a year at -20 degrees C; pyruvate shows a 6--8% loss after 3 days and 52% by one year at -20 degrees C; glycerol concentrations were stable at -20 degrees C for at least 13 days. Blank fluorescence is found in perchloric acid extracts of blood, necessitating blank runs for pyruvate, 3-hydroxybutyrate, glycerol, and alanine. The systems are simple to use, relatively inexpensive to operate, and are recommended for any laboratory with high throughput of samples.
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.
SUMMARY. 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 J.Lg of selenium-enriched yeast, 600 J.Lg 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.Selenium is an essential trace element and the recommended intake for man is 50-200 J.Lg per day.' The average British diet contains 60 J.Lg of selenium per day with half derived from cereals and cereal products, and another 40% from meat and fish.' Selenium is well absorbed and in normal circumstances 55-60% is excreted in urine and most of the rest in faeces. Selenite, selenate and selenoaminoacids can all be converted into selenide.' Selenium deficiency reduces the activity of the selenium-dependent enzyme glutathione peroxidase (GSH-Px) (EC 1.11
No abstract
SUMMARY 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 erthrocytes. The purpose of this study was, firstly, to establish reference ranges for concentrations of Se and GSH-Px activities in blood for apparently healthy adults living in the south of England and, secondly, the data have been analysed to determine the effect of several factors including smoking, alcohol, and the pill. Subjects and methods SUBJECTSA total of 391 apparently healthy subjects living within a 30 mile radius of Southampton volunteered for the study. They were asked whether they were vegetarians and, for women, whether they were taking an oral contraceptive. Details of their alcohol consumption and smoking habits were recorded according to the method of Shaper et al."' Table 1 gives full details. METHODSHaematological parameters were obtained using a Coulter S Plus. Initial experiments had shown that the activity of GSH-Px in blood remained stable at 4°C and -20°C for at least five days. Samples for GSH-Px activity were therefore stored at 4°C and' assayed within 48 hours of collection using an LKB reaction rate analyser, by the method described by Beutler17 using t-butyl hydroperoxide as substrate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.