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Biomedical subjects

G Adam

Publications and source records attributed to G Adam.

At least 325 records · Page 18Linked to original sources
PubMed1983

Only one of the two signals required for initiation of the cell cycle is associated with cellular accumulation of ribosomal RNA.

Two intracellular functions are elicited by the serum component in culture media in order to initiate the cell cycle: "competence" and "progression". Although both functions have to be present simultaneously for start of cell division, it is shown here for Swiss 3T3 cells that only one of them, the progression signal, is associated with reaccumulation of ribosomal RNA. This result points to the cellular complement of ribosomes as one of the limiting parameters for cell division.

Animals↗
PubMed1983

Proliferative activity and ribosomal RNA content of 3T3 and SV40-3T3 cells.

The phenomenon of resistance of confluent 3T3 cells to serum stimulation of proliferation is investigated and shown to depend drastically on the kinetics of application of growth factors with the serum. The cellular content of ribosomal RNA is determined flow-cytometrically by measuring the red fluorescence of cells stained with acridine orange. Ribosomal RNA content of 3T3 cells, but not of SV40-3T3 cells, is shown to decrease after confluence. The kinetics of restoration of ribosomal RNA in stimulated 3T3 cells exhibits an increasing delay with increasing duration of quiescence. These and further results are consistent with "progression" to initiation of the cell cycle being closely associated with restoration of cellular content of ribosomes.

Animals↗
PubMed1983

[Possibilities of whole-body hyperthermia].

Significant modifications in tissues, even death of cells, are caused by hyperthermia of few degrees centigrade. The extent of these modifications depends on the temperature applied. In a whole-body treatment, only not directly cytotoxic temperatures can be tolerated. The authors compare the methods of induction of whole-body hyperthermia with respect to expenditure, temperature applied, and side effects. Total-body hyperthermia aims at a reinforcement of other tumoricide therapies (radiotherapy, chemotherapy). - A pilot study performed with patients suffering from microcellular bronchial carcinomas, extensive disease, showed that the results of ACO and total-body hyperthermia (41 degrees C) are encouraging as compared with single ACO therapy: complete remission 8/15, partial remission 5/15, no change and progressive disease 2/15, 53-week survival rate 0,5, one-year survival rate 0,53, two-year survival rate 0,18.

Carcinoma, Small Cell↗
PubMed1981

Regulation of passive potassium transport of normal and transformed 3T3 mouse cell cultures by external calcium concentration and temperature.

Regulation of passive potassium ion transport by the external calcium concentration and temperature was studied on cell cultures of 3T3 mouse cells and their DNA-virus transformed derivatives. Upon lowering of external calcium concentration, passive potassium efflux generally exhibits a sharp increase at about 0.1 mM. The fraction of calcium-regulated potassium efflux is largely independent of temperature in the cases of the transformed cells, but shows a sharp increase for 3T3 cells upon increasing temperature above 32 degrees C. In the same range of temperature, the 3T3 cells exhibit the phenomenon of high-temperature inactivation of the residual potassium efflux at 1 mM external calcium. At comparable cellular growth densities, the transformed cell lines do not show high-temperature inactivation of "residual" potassium efflux. These results are consistent with the notion of a decisive role of the internal K+ concentration in the cell-density dependent regulation of cell proliferation. In particular, the growth-inhibiting effect of lowering the external Ca2+ concentrations is considered as largely due to a rise of passive K+ efflux and a subsequent decrease of internal K+ concentration. The experimental data on the Ca2+ dependence of passive K+ flux are quantitatively described by a theoretical model based on the constant field relations including negative surface charges on the external face of the membrane, which cooperatively bind Ca2+ ions and may concomitantly undergo a lateral redistribution. The present evidence is consistent with acidic phospholipids as representing these negative surface charges.

Animals↗
PubMed1981

Dependence of interfacial properties of normal and transformed 3T3 cell membranes on treatment with factors modifying proliferation.

Interfacial properties of the outer cell membrane of normal and transformed in vitro cultures of mouse 3T3 cells have been investigated. The contact angles of sessile drops on dried cell preparations were measured and the interfacial tensions derived using the thermodynamic approach introduced by Neumann. Interfacial tensions were found to be within an order of magnitude of those determined for other cell and model membranes. Treatment of cells with calf serum, a stimulant to proliferation, resulted in a decrease in the interfacial tension of normal and transformed cells, whereas use of concanavalin A and its succinylated derivative lead to an increase of interfacial tensions of both cell types. These and further results show a detailed correlation between the growth-regulating effects and the effects on interfacial properties of these proliferation-modifying factors. An interpretation of the results of serum depression of the interfacial tension in terms of a binding equilibrium dependent on the concentration of humoral growth factors in the medium is attempted.

Animals↗
PubMed1981

A new citrated formulation of nalidixic acid (Mictral U.K.) for the treatment of acute cystitis.

A 3-day course of a new citrated formulation of nalidixic acid (Mictral) was assessed in fifty-four women presenting with acute uncomplicated cystitis. Over 96% of women with a significant Gram-negative bacteriuria were cured of the infection following a course of treatment. Only two relapses occurred in this group during the follow-up period. Relief of symptoms occurred in nearly 90% of infected patients and generally by the second day of treatment. Although the incidence of side-effects was about 20% they were not considered serious.

Acute Disease↗
PubMed1981

[Complications in gastroenterological procedures and their surgical treatment].

It is reported on 29 complications after invasive diagnostic measures with a lethality of 43% conditioned by delay. Above all extreme age groups are concerned. Endoscopies, punctures, but also the preparing measures such as purification enemas must be done by experienced persons. Already the suspicion of a complication justifies the operative revision. Expectative behaviour is the main case for the high lethality.

Adult↗
PubMed1980

Increased fluorescein filling defects in the wall of the optic disc cup in glaucoma.

One hundred seventy-one optic disc fluorescein angiograms of glaucomatous, ocular hypertensive, and normal patients were studied for the occurrence of areas of hypofluorescence or absolute filling defects in the rim, wall, and floor of the optic cup using disc stereo photographs compared with the fluorescein angiogram. The frequencies of involvement of the rim, wall, and floor of the cup by filling defects were determined. The wall of the cup has a greater percentage of filling defects in subjects with glaucoma than in ocular hypertensive or in normal subjects. The floor of the cup has more filling defects in normal subjects than in those with glaucoma. The involvement of the wall of the cup increases with the degree of visual-field loss in glaucoma. We suggest that, in glaucoma, the effect of ocular pressure is greater on the wall of the cup than on the floor of the cup.

Fluorescein Angiography↗
PubMed1979

Dependence of intracellular alkali-ion concentrations of 3T3 and SV 40-3T3 cells on growth density.

Intracellular contents of potassium and of sodium are determined for 3T3 and SV 40-3T3 cells in dependence of growth density. In parallel, total cell volume and volume of intracellular water is determined for these cells suspended in physiological buffer. Intracellular potassium concentration thus evaluated for suspended 3T3 cells exhibits a sharp decrease at cellular growth densities which lead to density dependent inhibition of cell proliferation. In the case of SV 40-3T3 cells, this drop of potassium concentration with increasing cellular growth density is not observed, which correlates well with the absence of cell density dependent inhibition of cell growth in the transformed cell line. These results support the notion that processes of stimulation of quiescent 3T3 cells or of cell density dependent inhibition of their proliferation are mediated by processes including changes of potassium transport characteristics leading to increase or decrease respectively of their intracellular potassium concentration. Furthermore, these and other results suggest, that a difference between normal and transformed cells most relevant to their different proliferation behaviour might reside in different transport characteristics for potassium of the plasma membranes of these cells.

Animals↗
PubMed1978

[Steroid-examinations in serum of old men as a functional testing of the suprarenal glands (author's transl)].

A surgical intervention is dangerous for the old patient awing to the reduced reactiveness and polymorbity. The knowledge of the function of the suprarenal glands in stress (operation) is important. The latent insufficiency of the suprarenal glands is determined with the ACTH-stimulations test. 136 patients from 60 to 100 years were proved. In the case of a latent insufficiency of the suprarenal glands the substitution of glucocorticoids and ACTH is necessary.

11-Hydroxycorticosteroids↗