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Biomedical subjects

G B Gerber

Publications and source records attributed to G B Gerber.

At least 91 records · Page 5Linked to original sources
PubMed1977

Intestinal enzyme distribution after supralethal irradiation.

The activity of some intestinal enzymes has been studied after 2 kR irradiation. Brush border enzymes, maltase and leucineaminopeptidase (LAP) show an increase 20 hours after irradiation, while after 72 hours their activities are reduced to very low levels. Lysosomal enzymes show a completely different behaviour: acid phosphatase activity increases only 72 hours after irradiation, whereas beta glucuronidase increases significantly after 20 hours and reaches values two or three times higher than controls after 72 hours. The histologic picture at the first interval after irradiation shows gross alterations in the crypt region, but the villi appear nearly normal. Seventy-two hours after irradiation the whole epithelium is affected and very numerous leukocytes are present in the stroma.

Acid Phosphatase↗
PubMed1976

The radiosensitivities of lymphocytes from pig, sheep, goat and cow.

Dose-effect curves for X-irradiation in vitro were determined on cultured blood lymphocytes of four mammalian species-cow, goat, sheep and pig-having approximately the same number of chromosome arms, the same nuclear volume and the same DNA content. The data from cow, but not those from the other species, exhibited significant inhomogeneity between the experiments. On inspection the numerical yields appear not to differ greatly in the lower dose range. Evaluation of the parameters according to the quadratic law and the power law, however, demonstrate significant differences. Pig differs from the other species regardless of which presentation is chosen. For the power law a significant difference is also found between goat and sheep.

Animals↗
PubMed1976

Action of lead on early divisions of the mouse embryo.

The number of cells in mouse embryos 48 h after mating was studied in normal and lead-treated females (0.125, 0.25, 0.5, 1% of lead in the diet). The percentage of embryos in the 4-cell stage compared to those in the 8-cell stage increased after 0.125, 0.25 and 0.5% of dietary lead. After the highest dose an increase in nondivided eggs was also seen which occurred at the expense of 4-cell embryos. The different possibilities, delay of all divisions, delay of only the first division and action of lead on only a part of the embryonic population, are discussed.

Animals↗
PubMed1976

[Measurement of the blood flow in various areas of the rat brain by means of microspheres].

A method is described to measure regional blood flow in different structures of the rat brain. Microspheres (15 micron) are injected, the brain is sectioned, stained for myeline, radioautographs are prepared and the microspheres in the different structures are counted. The values obtained for different brain structures are counted. The values obtained for different brain regions (cortex, corpus callosum, thalamus hipocampus, hypothalamic region, colliculi, cerebellum, pons, medulla) compare well with those published by others on larger animals. In rats fed 1% of lead from birth, higher blood flow is found in the cortex and a lower one in the interior part of the brain compared to controls.

Animals↗
PubMed1976

Late effects in the central nervous system. A study of biochemical alterations after local exposure of the rat brain to 2 krd.

The brain area of female rats three months of age was exposed to 2 krd of X-rays, and various biochemical parameters were retermined as well as NAD(H) in vivo fluorescence of the brain surface after time intervals from one day to 18 months. During the early period, an increase in the uptake of alpha-aminobutyrate (AIB) and a temporary depression in beta-glucuronidase and cathepsin activity followed by an activation at one month was seen. Somewhat later, acid phosphatase increases. During the intermediate period, DNA and serotonin content and AIB uptake by brain increase, whereas AIB uptake by heart and muscle decreases. A fall in sialic acid content is also noted at this time. During the late phase collagen increases, AIB uptake by brain and liver decreases. No changes were found with respect to NAD(H) fluorescence and its response to breathing of low oxygen concentrations.

Acid Phosphatase↗
PubMed1975

Renal function and intra/extravascular distribution spaces in the rat after supralethal whole-body x-irradiation.

Renal function and distribution of 51Cr-EDTA in intra/extravascular space has been studied in rats suffering from the gastro-intestinal syndrome after supralethal doses of X-irradiation. Urine excretion and glomerular filtration were found to decrease until 50 hr p.i. Urine excretion and, in a less degree, glomerular filtration rate increase then to a peak at 67 hrs before falling off to zero values before death. The extravascular space was found to be expanded in several organs from 60 hrs on (kidney, liver, stomach, intestine). Only in kidney where weight follows changes in extravascular space, a return to normal values is seen before death. An expansion in extravascular space due to a reduced re-extraction into intravascular space and diminished excretion constant can also be discerned beginning early after exposure on the basis of compartmental analysis of the blood activity-time curves. It is postulated that the changes observed reflect a state of shock developing slowly after irradiation and entering its irreversible stage 60 to 65 hrs after exposure.

Animals↗
PubMed1975

Regional blood flow in rats exposed to supralethal doses of whole body x-irradiation.

Relative blood flow in different organs of the supralethally (3 kR) whole body X-irradiated rat was studied using labeled 15 mu microspheres. Immediately after irradiation blood flow in brain diminishes. From 10 to 20 hrs a phase of increase in blood flowing to many parenchymal organs ensues. A second maximum 45 to 50 hrs and a third one at 60 hrs. In most organs except in brain and liver relative blood flow diminishes before death. The genesis of these changes as signs of a slowly developing shock is discussed.

Animals↗
PubMed1975

Embryonic death in mouse due to lead exposure.

Female mice which displayed a vaginal plug after mating were given a diet containing 0, 0.125, 0.250, 0.500% of lead as lead acetate and were dissected 16 to 18 days later. Lead treatment was found to reduce significantly the incidence of pregnancies and to increase the postimplantation loss in the pregnant females.

Animals↗
PubMed1975

Influence of phospholipids on liver damage. II. Changes in lipid content and synthesis after liver damage with carbontetrachloride and other agents.

Content and synthesis of lipids were studied in rats after carbontetrachloride poisoning and different treatments with phospholipids (EPL), as well as in some other conditions under which an increase in lipids occurs. The increase in neutral lipids during CCl4 poisoning is significantly reduced by pretreatment and--somewhat less--by posttreatment with EPL. Incorporation of acetate into triglycerides, phospholipids and cholesterol increases in CCl4 poisoning and this was not affected by EPL. Moreover, treatment with EPL had but little effect on the lipid accumulation induced by orotic acid feeding and partial hepatectomy. EPL promoted, however, slightly DNA synthesis after partial hepatectomy and protected DNA in thymus after whole body X-irradiation.

Acetates↗
PubMed1975

Serotonin and proteolytic enzymes in brain of irradiated animals.

Early and late irradiation effects on biogenic amines (5-HT and NA) contents, intracellular hydrolytic enzyme activity and MAO in brain tissue was studied on mice and rats. In mice in the majority of cases (irradiated on the first day after birth) there occurs a remote effect of irradiation in the form of the increase in 5-HT content and different, species-dependent, changes in hydrolytic activity. Among early effects (24 hrs following the irradiation) the decrease in 5-HT and NA contents was stated in rats. These changes were accompanied by the increase in MAO and hydrolytic (proteolytic) activities.

Acid Phosphatase↗
PubMed1975

Influence of phospholids on liver damage. I. Carbontetrachloride poisoning and alterations in amino acid uptake, peroxidation, sialic acid content, and lysosomal enzymes.

Changes in peroxidation, amino acid uptake [alpha-amino isobutyrate (AIB)], sialic acid content and lysosomal enzymes were followed in rats after carbon-tetrachloride enzymes were followed in rats after carbontetrachloride poisoning and treatment with phospholipids (EPL). Uptake and retention of AIB by liver and brain increased after CCI4 poisoning. EPL had no effect on these changes. EPL diminished markedly, however, the excessive peroxidation caused by CC14.

Aminoisobutyric Acids↗
PubMed1975

Absorption of radioactive lead (210Pb) by different parts of the intestine in young and adult rats.

Absorption of radioactive lead (210Pb) was studied in an intestinal preparation from adult and young rats. Absorption was higher in the jejunal parts than in the duodenum or colon. Moreover, absorption in young rats was greater than in adults. No difference in absorption was found after loading with large amounts of lead. Maintaining the animals on a low calcium diet decreased rather than increased lead absorption.

Animals↗
PubMed1974

Analytic methods for biochemical indicators of radiation injury.

Since the development of biochemical indicators of radiation injury has been hampered often by the lack of simple and rapid methods of determination, techniques for the measurement of 30 urinary compounds are presented. These methods have been in part taken from the literature, in part they have been modified or developed by us. They represent a compromise between speed and simplicity of execution and specificity of assay.

Animals↗