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Biomedical subjects

H Gerhard

Publications and source records attributed to H Gerhard.

54 records · Page 3Linked to original sources
PubMed1976

Chromosomal studies of human prostatic tumors in vitro.

Chromosomal studies were performed on primary cultures from human prostatic adenomas and carcinomas. All cells from both tumor types showed diploid chromosomal counts with a normal human karyotype. Chromosomal analysis was also performed on cells of the permanent epithelial line EB 33 derived from a human prostatic carcinoma in this laboratory. In contrast to the primary cultures, hypotriploid chromosome numbers were found during continuous culture for more than 1 year. The range of chromosome numbers increased with time in culture and was reduced to the original model number of 64 by only one animal passage ("nude" mice). Feulgen fluorometry on different passages of the permanent cell line EB 33 showed tetraploidy. This discrepancy to the hypotriploid chromosome number can be explained by different Feulgen hydrolytic properties of the different cell types.

Animals↗
PubMed1975

[Proliferation kinetics of bile duct epithelia in the regenerating mouse liver after CCl4-poisoning].

Autoradiographic and morphometric methods were used in studying the proliferation of interlobular bile duct epithelia of adult NMRI mice after CC14-poisoning (1 ml/kg i.p.). DNA synthesis starts on the 2nd day after CC14 administration. The time course of the 3H-thymidine labelling index is biphasic, with a first maximum at 2.5 and a second one 5 days after CC14 injection. An S-phase of 5.8 h was measured by 3H plus 14C-TdR double-labelling experiments. Proliferation is completed 10 days after CC14-poisoning, coinciding with the restitution of the liver parenchyma. Bile-duct epithelia remain diploid during the whole proliferative period, which suggests that every S-phase leads to mitotic division. The number of duct cells in portal cross sections remains constant. A quantitative model of the CC14- induced proliferation of interlobular bile duct cells is presented after calculating the total number of S-phases, the increase in cell number, and the final percentage of 3H-labelled nuclei (continuous infusion of 3H-TdR) as a function of time: With regard to 100 bile duct cells at the onset of proliferation 20 per cent S-phases occur during the first maximum and an additional 26 per cent occur during the second maximum of DNA SYNTHESIS, WHICH LEADS TO A 1.46-FOLD INCREASE IN CELL NUMBER. As derived from continuous 3H-TdR labelling (48 per cent 3H-labelled nuclei at the 6th day) and autoradiographic grain density measurements, the second wave of S-phases is due to DNA synthesis in ductular cells that have been formed during the first proliferative maximum. It is not possible to determine whether the proliferative activity observed is induced by lethal damage to bile-duct cells in the early course of CC14-poisoning, followed by compensatory growth and replacement of degenerate cells, or by nonspecific growth stimulation, inducing hyperplastic growth and elongation of terminal bile ducts.

Animals↗
PubMedDate not supplied

A non-pharmacologic approach to the treatment of exercise-induced bronchospasm.

We investigated the effects of breathing air warmed and fully saturated to body temperature (AWS) before, during, and after exercise in asthmatic subjects. Airway responses to submaximal exercise on a cycloergometer were measured on four separate days in 14 asthmatic volunteers. On day 1 the subjects exercised breathing ambient air (AA). On the subsequent three days exercise was performed with the subjects breathing AWS, (1) for five minutes preceding, (2) during, and (3) for five minutes following exercise. We showed complete protection against EIB by AWS during exercise, but no protection by AWS before or after exercise. On two subsequent days we examined the effects of partially warming and humidifying the subjects' inspired air by having them wear a mask during exercise. We found that with such protection bronchospasm was significantly but not completely blunted. We conclude that the physiologic changes initiated during exercise can be prevented by breathing AWS during exercise, but are not by AWS inhaled before or after exercise. Furthermore, these studies demonstrate the possibility of using masks as a non-pharmacologic means of controlling EIB.

Adult↗