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Biomedical subjects

A Günther

Publications and source records attributed to A Günther.

87 records · Page 5Linked to original sources
PubMed1986

Decreased autolysis of dead cells in adriamycin-resistant lines of the sarcoma 180 of mouse.

Adriamycin-resistant cell lines of the sarcoma 180 of mouse reveal, besides the known resistance mechanism, a decrease in cellular autolysis compared with the original line. This decrease has been demonstrated by comparative analysis of cell-free supernatants isolated from 7-day-old sensitive and resistant ascites tumors in mice. In order to demonstrate these changes we isolated and quantified the DNA, detecting higher amounts within the supernatants of resistant lines. Furthermore, unspecific DNA-cleaving activity within raw homogenates of the cells is substantially lower in the resistant lines. Residual parts of chromatin may trap the drug and in this way lower its effective concentration. However, the results may also reflect changes in enzymatic complement playing a hitherto unknown role within living cells.

Animals↗
PubMed1986

Ia antigens in plastic-embedded tissues: a post-embedding immunohistochemical study.

The aim of the present study was to establish a plastic embedding technique that makes possible the immunohistochemical demonstration of class II major histocompatibility complex (MHC) antigens (Ia antigens) in undecalcified joint tissues. Therefore a series of fixatives and dehydrating agents was tested for saving Ia immunoreactivity by post-embedding immunostaining of thin sections (2 microns) of rat tissues that had been embedded in glycol methacrylate (GMA), and by comparing with cryostat sections. An indirect immunoperoxidase and the avidin-biotin complex (ABC) technique were used. Combined with fixation by 4% formaldehyde, dehydration with GMA was found to give the best preservation of Ia antigenicity, followed by dehydration with ethylene glycol. The thinness of tissue sections facilitated the association of Ia antigens with different subcellular compartments in distinct cell populations. These various patterns are described.

Animals↗
PubMed1984

Differential expression of intermediate-filament proteins in murine sarcoma 180 ascites or solid tumor.

The intermediate-filament proteins in Sarcoma 180 ascites cells and solid tumors generated by s.c. injection of ascites cells in NMRI or nude mice were analyzed by one- and two-dimensional gel electrophoresis and identified by immunological methods. The ascites form of Sarcoma 180 coexpresses keratin and vimentin, whereas the solid tumor ceases to synthesize keratins but continues to express vimentin. These reversible changes in the expression of intermediate-filament proteins may be due to a change in the differentiation program induced by environmental conditions like growth with or without cell contact.

Animals↗
PubMed1983

Blockade by neurotransmitter antagonists of veratridine-activated ion channels in neuronal cell lines.

The voltage-dependent Na+ ionophore of various neuronal cells is permeable not only to Na+ ions but also to guanidinium ions. Therefore, the veratridine- (or aconitine-)stimulated influx of [14C]guanidinium in neuroblastoma x glioma hybrid cells was measured to characterize the Na+ ionophore of these cells. Half-maximal stimulation of guanidinium uptake was seen at 30 microM veratridine. At 1 mM guanidinium, the veratridine-stimulated uptake of guanidinium was lowered to 50% by approximately 60 mM Li+, Na+, or K+ and by a few millimolar Mn2+, Co2+, or Ni2+. The basal, as well as the veratridine-stimulated, uptake of guanidinium was inhibited by the cholinergic antagonists (+)-tubocurarine (Ki = 50 to 500 nM) and atropine (Ki = 5 to 30 microM) and the adrenergic antagonists phentolamine (Ki = 5 microM) and propranolol (Ki = 60 microM). The specificity of the inhibitory effects of these agents is stressed by the ineffectiveness of various other neurotransmitter antagonists. However, the corresponding ionophore in neuroblastoma cells (clone N1E-115) seems to be regulated differently. While phentolamine and propranolol inhibit the veratridine-activated uptake as in the hybrid cells, (+)-tubocurarine and atropine exert only a slight effect.

Animals↗
PubMedDate not supplied

Rapid recovery from cognitive deficits in abstinent alcoholics: a controlled test-retest study.

The pattern of cognitive deficits and their time-dependent recovery were investigated in a cohort of 49 male alcohol-dependent patients using a repeated measurement design with 49 healthy male controls matched for age, education, and marital status. We combined parts of the Halstead Reitan Battery and the Wechsler Memory Scale with tests that are widely used in German-speaking countries. Patients were tested in the first week (T1) and 5 weeks later (T2) at the end of the in-patient treatment programme. Matched controls were tested also at T1 and T2, which enabled us to take learning effects into account. At T1, the patients showed distinct cognitive deficits on 5 of 12 neuropsychological parameters (perceptual-motor speed, verbal short-term memory, verbal knowledge, non-verbal reasoning, spatial imagination). At T2, significant improvements had occurred in four of the five dysfunctional domains with a significant difference remaining in verbal short-term memory. Duration of dependency and length of abstinence prior to testing had no essential effects on neuropsychological functions. Our results provide evidence for the well-established fact that chronic alcoholism has detrimental effects on cognitive performance, but that performance improves with neuropsychological recovery which occurs rapidly within weeks when abstinence is maintained. Cognitive deficits seem to be similar across different studies and cultures.

Adult↗
PubMedDate not supplied

Synthesis and studies on the biophysical activity of human lung surfactant peptide SP-C and its N-terminal fragments.

Human lung surfactant peptide SP-C and two of its N-terminal fragments were prepared by SPPS and their biophysical activities investigated in vitro using a pulsating bubble surfactometer. These studies demonstrated that even low doses of the synthetic peptides with the natural human sequence of SP-C in combination with reconstituted lipid mixtures causes a drastic decrease of surface tension.

Amino Acid Sequence↗