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Biomedical subjects

G Neupert

Publications and source records attributed to G Neupert.

At least 73 records · Page 4Linked to original sources
PubMed1976

Acid mucopolysaccharides in fibroblast cultures. 1. Influence of cell density, pH-value and lactate concentration on the MPS distribution pattern.

From cells and culture media of embryonic rat fibroblasts (1st subculture) the acid mucopolysaccharides were isolated and fractionated. The per cent calculation of the 6 fractions was based on the content of glucuronic acid. The cultures were maintained as follows: 0.5 X 10(6) to 3 X 10(6) cells were examined in Demeter flasks at pH 7.4 or 6.6; lactate concentration was enhanced to 100 mg%. The amount of each fraction was correlated with the cell density (linear regression). The pH-value and lactate concentration in connection with cell density proved to be important factors in the modification of the MPS distribution pattern.

Animals↗
PubMed1976

[Evaluation of Brdicka's reaction in tumor diagnostic (author's transl)].

We have investigated the polarographic behaviour of sera from patients of an ORL-department by means of Brdicka reaction. It could be shown, that patients with cancer or acute inflammation had significantly increased values. But the arithmetic mean of this groups is enclosed by the scattering of the normal collective, therefore is no practically use for diagnostic purposes possible.

Carcinoma, Squamous Cell↗
PubMed1975

[Clinical-biochemical study of systemic panchondritis].

With the help of a casuistic and the results of own investigations clinical, differential-diagnostic, biochemical, pathogenetic and therapeutic aspects of panchondritis systemica are described. The very rare clinical picture, which coincides with chondrolysis and perichondritis, manifests itself intermittently in the region of the auricles, the nose, the cartilaginous parts of the ribs as well as of the chondroskeleton of the respiratory system and in most cases has a fatal termination. Probably on the basis of the pathogenetically decisive changes of the basic substance in addition to this arthritic symptoms, symptoms similar to Bechterew's disease, carditic as well as ocular and internal ear symptoms may appear. Results of own investigations refer to considerable abnormalities in the glucosamine glycan metabolism, in which case the question must remain open, whether these biochemical and immunologic factors are to be regarded as the primary pathogenetic cause. For avoiding irreparable and dangerous defects of the cartilage a sufficiency dosed treatment with corticoids is necessary.

Adult↗
PubMed1975

Hypoxia in fibroblast cultures. I. Changes in glucose consumption by 5 vol.-% oxygen concentration and reduced pH.

In secondary cultures of rat embryonic fibroblasts the glucose consumption and lactate concentration were comparatively investigated in 5 and 21 Vol.-% O2 environment at pH 6.6 and pH 7.4 (HEPES-buffer). The results were correlated with cell density. The following observations were made: 1. At pH 6.6 the rate of cell proliferation was reduced to 81%; by additional hypoxia it was reduced to 71%. 2. Increase in cell density effectuated decrease of glucose consumption and lactate production at pH 7.4 and pH 6.6 in 5% as well as in 21% O2 environment. 3. At pH 7.4 enhancement of glucose consumption and lactate production due to hypoxia can be observed only at low cell density. 4. At pH 6.6 respiration of fibroblasts was little influenced by 5% O2 environment. 5. Transition from pH 7.4/21% O2 to pH 6.6/5% O2 effectuated decrease in glucose consumption and lactate concentration in tissues in hypoxic environment. This suggests a pH-governed feedback mechanism. Abbreviations used in the text: c-AMP = cyclic adenosine monophosphate; MPS = acid mucopolysaccharides (glycosaminoglycans).

Animals↗
PubMed1975

Concanavalin A receptors in the plasma membrane of rat liver cells: comparative electron microscopic studies on normal cells and on cells in vivo transformed by diethylnitrosamine.

The Concanavalin A receptors at the cell surface of normal rat liver cells and of those in vivo transformed by diethylnitrosamine were comparatively studied by electron microscopic cytochemistry. Besides different agglutinability of the cells a variable surface staining of the cells by the Con A-peroxidase reaction (BERNHARD and AVRAMEAS 1971) was observed. After performance of the cytochemical reaction on living normal rat liver cells in situ a continuous cell surface staining was seen. In transformed rat liver cells a marked tendency for patchy distribution of the Con A label at the cell surface occurred. Furthermore, internalisation of Con A-peroxidase labeled plasma membrane segments was visible in the transformed cells. A similar variable labeling by Con A-peroxidase reaction occured also in the "basal" plasma membrane of normal and transformed rat liver cells. The results are discussed with respect to the importance concerning the mobility of lectin receptors and membrane stability.

Animals↗
PubMed1975

Interaction of Lens culinaris lectin, concanavalin A, Ricinus communis agglutinin and wheat germ agglutinin with the cell surface of normal and transformed rat liver cells.

The observation of BOREK et al. (1973) on nonagglutinability of transformed rat liver cells by Lens culinaris lectin and our ultrastructural findings of a greater mobility of the Lens culinaris lectin receptors on transformed rat liver cells as compared to normal rat liver cells (ROTH 1975) initiated the present agglutination experiments on liver cells with lectins. For agglutination assay the microhemadsorption technique after FURMANSKI et al. (1973) was used with exception of several tests on EDTA-detached cells. The transformed rat liver cells exhibited, in contrast to the findings of BOREK et al. (1973), a positive microhemadsorption with Lens culinaris lectin as well as with Concanavalin A, Ricinus communis lectin and wheat germ agglutinin whereas the normal rat liver cells became positive only after a brief trypsin treatment. The significance of the difference in agglutinability of rat liver cells with Lens culinaris lectin and the other lectins used is discussed with regard to the cell-cell interaction mediated by lectins.

Agglutination Tests↗
PubMed1975

Growth inhibition and morphological changes caused by indomethacin in fibroblasts in vitro.

In a definite range of concentrations indomethacin inhibits the multiplication of fibroblasts in vitro without influencing their viability. The effect of lethal doses of indomethacin on the fine structure of normal and transformed fibroblasts was investigated by light and electron microscopy. The cells grown in flat monolayers became roundish and, varying in sequence, small zeiotic blebs were bulging at the external cell membrane. Beside coarse vesicular transformation of the endoplasmatic reticulum and extension of the perinuclear spaces ballooning of the mitochondria occurred. After breaking up of the vesicles of the endoplasmatic reticulum loosening of the cytoplasmic ground substance associated with enlargement of the hyaline plasma margins was observed in further progress of the experiment. The internal structures of the mitochondria were completely disorganized. In the ultrastructure of the fibroblasts altered by lethal doses of indomethacin no specific sites of drug action could be identified.

Animals↗
PubMed1975

[Tissue compatiblity of stomatologic materials in cell cultures].

The paper contains results of investigations on the suitability of cell cultures for biological testing of soluble substances from dental cements and their components. The preparation of the specimens as well as the elution process are described. Furthermore the culture system of cell populations in vitro and representative biological parameters are reported.

Adult↗
PubMed1975

[Comparative in vitro study on cellular reactions to soluble components of EBA and phosphate cement].

While the eluate of EBA cement does not have any toxic effect on the cell populations, the cells are noticeably damaged by the pH-corrected eluate of freshly mixed phosphate cement. Comparison between the cellular reaction to eluates and the solubility of the cements shows that the toxic effect is not a priori dependent on the composition of the material, but on the degree of dissolution which is primarily determined by the environment and the mixture ratio. The solutions of cement powder do not have any irritating effect on the cultivated cells. However, due to its content of eugenol, the EBA cement fluid solved in a considerably weaker concentration in the culture medium than the phosphate cement fluid damages the cells to such an extent that they die.

Animals↗
PubMed1975

Hypoxia in fibroblast cultures. 2. Influence of pH on the distribution pattern of acid mucopolysaccharides.

Secondary cultures of embryonic rat fibroblasts [NEUPERT et al., Exp. Path. 7, 19-28 (1972)] were cultured in 21% and 5% O2 concentration at pH 6.6 and 7.4 for 6 or 8 days. The acid mucopolysaccharides were isolated and fractionated by alcohol precipitation, papain digestion, CPC-precipitation and fractionation after the microtechniques of SVEJCAR and ROBERTSON [see KITTLICK and NEUPERT, Exp. Path. 7, 7-18 (1972)]. Cells and medium were investigated together. The results were related to cell density and compared with the glucose and lactate values [see KITTLICK and NEUPERT, Exp. Path. 10, 109-114 (1975)]. Concerning the question of interrelations of MPS-synthesis and glycolysis a survey on literature is given. Our own test results were as follows: 1. Hypoxia (5% O2) did not influence MPS-total synthesis. 2. Depending on cell density the individual MPS fractions were different in their reaction to hypoxia. 3. Hyaluronic acid (and heparan sulphate) in the MPS-pattern showed other behaviour than chondroitin sulphate and dermatan sulphate, respectively. 4. At low cell density hypoxia effectuated increase in hyaluronic acid and decrease in chondroitin sulphate and dermatan sulphate, respectively. 5. At high cell density hypoxia effectuated decrease in hyaluronic acid and increase in chondroitin sulphate and dermatan sulphate, respectively. Possible relationship to processes in the tissue is discussed.

Animals↗