scholarly journals THE INFLUENCE OF CHANGING CELL KINETICS ON FUNCTIONAL DIFFERENTIATION IN THE SMALL INTESTINE OF THE RAT A STUDY OF ENZYMES INVOLVED IN CARBOHYDRATE METABOLISM

1974 ◽  
Vol 22 (5) ◽  
pp. 352-360 ◽  
Author(s):  
N. J. DE BOTH ◽  
H. PLAISIER
Keyword(s):  
Carbohydrate Metabolism ◽  
Enzyme Activities ◽  
Cell Kinetics ◽  
Specific Activity ◽  
Functional Differentiation ◽  
Radiation Doses ◽  
Germ Free ◽  
Cell Age ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Low Radiation Doses

The activity of a number of enzymes involved in carbohydrate metabolism was measured in different cellular compartments of the intestinal epithelium by microchemical techniques. The enzyme activities were related to different cell positions along crypt and villus and to cell age. Enzyme activities in proliferating, differentiating and functional cell compartments of the intestine of normal rats were compared with those in which the cell kinetics had been modified. The effect of increased proliferative activity within the crypt of normal animals was studied in the intestine during recovery after low radiation doses. The effect of increased life-span was investigated in germ-free animals. The specific activity of α-glucosidase, present in microvilli, was found to increase considerably during cell differentiation and subsequent cell migration along the villus. Its specific activity remained unchanged in isolated intestinal loops deprived of dissaccharide substrate for 6 weeks. Lactate dehydrogenase and, to a lesser extent, glucose 6-phosphate dehydrogenase show a similar pattern of activity to α-glucosidase. In contrast hexokinase and isocitrate dehydrogenase were equally distributed among crypt and villus cells and no clear differences were observed with increasing cell age. Increased proliferation in the crypts during recovery after low radiation doses resulted in a marked decrease in both crypt and villus cells of activity of α-glucosidase. The germ-free state of the intestine also significantly influences the pattern of α-glucosidase but has little influence on the other enzymes tested.

scholarly journals The effects of grass and concentrate diets on the specific activities of some enzymes of hepatic carbohydrate metabolism in sheep

1976 ◽  
Vol 35 (3) ◽  
pp. 407-411 ◽  
Author(s):  
J. Pearce ◽  
E. F. Unsworth
Keyword(s):  
Carbohydrate Metabolism ◽  
Malate Dehydrogenase ◽  
Specific Activity ◽  
Glycolytic Enzymes ◽  
Phosphogluconate Dehydrogenase ◽  
Specific Activities ◽  
Glucose 6 Phosphate Dehydrogenase

1. Feeding sheep a concentrate diet compared with grass diets increased the hepatic specific activities of the three glycolytic enzymes studied, and that of glucose-6-phosphate dehydrogenase (EC 1.1.1.49), and reduced the specific activity of D-fructose-1,6-diphosphate 1-phosphohydrolase (EC 3.1.3.11). The specific activities of phosphogluconate dehydrogenase (EC 1.1.1.43) and malate dehydrogenase (decarboxylating) (NADP) (EC 1.1.1.40) were unaffected by diet.

Effect of low radiation doses on microbe population in space stations

2002 ◽  
Vol 8 (5-6) ◽  
pp. 58-61
Author(s):  
V.V. Tsetlin ◽  
◽  
E.A. Deshevaya ◽  
N.D. Novikova ◽  
N.A. Polikarpov ◽  
...  
Keyword(s):  
Radiation Doses ◽  
Low Radiation Doses ◽  
Microbe Population

Eye protection in interventional procedures

2021 ◽  
Vol 94 (1126) ◽  
pp. 20210436 ◽  
Author(s):  
Beth A. Schueler ◽  
Kenneth A Fetterly
Keyword(s):  
Interventional Procedures ◽  
Eye Lens ◽  
Radiation Doses ◽  
Radiation Induced ◽  
Individual Actions ◽  
Dose Measurements ◽  
Dose Levels ◽  
Patient Radiation Dose ◽  
Low Radiation Doses

Data suggest that radiation-induced cataracts may form without a threshold and at low-radiation doses. Staff involved in interventional radiology and cardiology fluoroscopy-guided procedures have the potential to be exposed to radiation levels that may lead to eye lens injury and the occurrence of opacifications have been reported. Estimates of lens dose for various fluoroscopy procedures and predicted annual dosages have been provided in numerous publications. Available tools for eye lens radiation protection include accessory shields, drapes and glasses. While some tools are valuable, others provide limited protection to the eye. Reducing patient radiation dose will also reduce occupational exposure. Significant variability in reported dose measurements indicate dose levels are highly dependent on individual actions and exposure reduction is possible. Further follow-up studies of staff lens opacification are recommended along with eye lens dose measurements under current clinical practice conditions.

Cytokines increase rat lung antioxidant enzymes during exposure to hyperoxia

1989 ◽  
Vol 66 (2) ◽  
pp. 1003-1007 ◽  
Author(s):  
C. W. White ◽  
P. Ghezzi ◽  
S. McMahon ◽  
C. A. Dinarello ◽  
J. E. Repine
Keyword(s):  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Antioxidant Enzyme ◽  
Enzyme Activities ◽  
Tumor Necrosis ◽  
Interleukin 1 ◽  
Antioxidant Enzyme Activities ◽  
Rat Lung ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Necrosis Factor

Pretreatment with the combination of tumor necrosis factor/cachectin (TNF/C) and interleukin 1 (IL-1) increased glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD) activities in lungs of rats continuously exposed to hyperoxia for 72 h, a time when all untreated rats had already died. Pretreatment with TNF/C and IL-1 also increased, albeit slightly, lung G6PDH and GR activities of rats exposed to hyperoxia for 4 or 16 h. By comparison, no differences occurred in lung antioxidant enzyme activities of TNF/C and IL-1- or saline-pretreated rats exposed to hyperoxia for 36 or 52 h; the latter is a time just before untreated rats began to succumb during exposure to hyperoxia. The results raise the possibility that TNF/C and IL-1 treatment can increase lung antioxidant enzyme activities and that increased lung antioxidant enzymes may contribute to the increased survival of TNF/C and IL-1-pretreated rats in hyperoxia for greater than 72 h.

scholarly journals The photocarcinogenicity of anthracence: photochemical binding to deoxyribonucleic acid in tissue culture

1975 ◽  
Vol 149 (1) ◽  
pp. 289-291 ◽  
Author(s):  
G M Blackburn ◽  
P E Taussig
Keyword(s):  
Molecular Weight ◽  
Tissue Culture ◽  
High Molecular Weight ◽  
Deoxyribonucleic Acid ◽  
Radiation Doses ◽  
Mammalian Tissue ◽  
Hydrocarbon Molecule ◽  
High Radiation ◽  
High Molecular Weight Dna ◽  
Low Radiation Doses

Anthracene becomes covalently bound to high-molecular-weight DNA in mammalian tissue culture as a result of irradiation at 365 nm after the incubation of cells with the hydrocarbon. At high radiation doses, the extent of binding exceeds one hydrocarbon molecule per 103 bases, and is lethal. At low radiation doses, much decreased binding is observed, but a majority of cells remain viable and can be recultured.

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