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Biomedical subjects

M Stark

Publications and source records attributed to M Stark.

137 records · Page 8Linked to original sources
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Influence of 5-azacytidine on differentiation and growth in rat nervous system tumor cell lines.

In vitro studies with permanent cell lines derived from ENU-induced rat CNS and PNS tumors have shown that substances acting on second messenger systems as well as glucocorticoids have a cytostatic effect at high cell densities, but enhance proliferation at low densities. The nontoxic cytostatic effects are partially accompanied by the induction of differentiation monitored by immunocytochemistry with antibodies against GFAP, S-100 and PKC (alpha,beta). Cell differentiation with or without the influence of the drugs applied could be highly facilitated in some (CNS), but not all (PNS) types of tumor cells from neuroectodermal origin by pretreatment of cultures with 5-azacytidine under demethylating noncytostatic conditions. The implications of our results are relevant for molecular neurobiology and might offer new therapeutical approaches and may provide models for neurotoxicology.

Animals↗
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Modulation of glial cell differentiation by exposure to lead and cadmium.

The influence of the neurotoxic agents lead and cadmium on human glioma cells (86HG-39, 87HG-31, 88HG-14, and A172) and rat glioma cells (F98 and RG2) was investigated in vitro by means of immunocytochemistry and growth data. Both heavy metals increased the growth rate, decreased the expression of differentiation markers (glial fibrillary acidic protein, S100 protein), and increased the expression of the malignancy marker transferrin receptor. The results indicate a decrease in the level of differentiation and impairment of glial cell function. Consequently, the neurotoxicity of Pb and Cd may be attributed to direct action not only on neurons but also on glial cells necessary for neuronal function. Possible molecular mechanisms are discussed.

Animals↗
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A new candidate region for the positional cloning of the XLP gene.

X-linked lymphoproliferative disease (XLP) is an inherited immunodeficiency characterised by selective susceptibility to Epstein-Barr virus and frequent association with malignant lymphomas chiefly located in the ileocecal region, liver, kidney and CNS. Taking advantage of a large bacterial clone contig, we obtained a genomic sequence of 197620 bp encompassing a deletion (XLP-D) of 116 kb in an XLP family, whose breakpoints were identified. The study of potential exons from this region in 40 unrelated XLP patients did not reveal any mutation. To define the critical region for XLP and investigate the role of the XLP-D deletion, detailed haplotypes in a region of approximately 20 cM were reconstructed in a total of 87 individuals from 7 families with recurrence of XLP. Two recombination events in a North American family and a new microdeletion (XLP-G) in an Italian family indicate that the XLP gene maps in the interval between DXS1001 and DXS8057, approximately 800 kb centromeric to the previously reported familial microdeletion XLP-D.

Base Sequence↗
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Analysis of umbilical artery flow parameters during fetal variable decelerations using computerized Doppler waveforms.

Umbilical artery velocity waves were obtained by Doppler ultrasonography before, during, and after 20 episodes of fetal heart rate (FHR) variable decelerations (VD) during the active stage of labor in 8 women. During 50% of the VD periods, the umbilical artery resistance flow parameters increased significantly (p < 0.01). The increase in resistance preceded the decrease in FHR in six episodes (30%) of VD (AR-VD group; arterial resistance VD) and did not precede the change in FHR in another ten episodes (50%) of VD (VR-VD group; venous resistance VD). In the AR-VD group the FHR accelerations occurred before the decelerations in only 1 case (17%), while in the VR-VD group FHR accelerations preceded the decelerations in 8 out of the 10 episodes (80%). Using these Doppler studies, it may be possible to differentiate between two groups of VD: AR-VD - which are caused by umbilical artery occlusion and thus preceded by a measurable increase in umbilical artery resistance - and VR-VD - which are not preceded by a measurable increase in umbilical artery resistance and may be caused by fetal hypoxia.

Adult↗
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A system for delivering care.

Despite partners and relatives providing care prior to a hospital admission, all too often they are not involved or informed about the treatment process during a patient's stay in hospital. The primary nurse system is an effective way of delivering care within the mental health framework. The primary nurse is responsible and accountable for the patient throughout his/her stay in hospital. Peplau's model of nursing care concentrates on the development of the nurse-patient relationship. Care plans should be negotiated with the patient. Care plan meetings are useful for discussing problems, receiving feedback and for supporting colleagues. Family meetings are essential so that the main carer's continuing involvement in care can be acknowledged.

Adult↗
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Characterization of a new permanent squamous carcinoma line from human lung B 109.

A permanent squamous carcinoma cell line was established from human lung. The cells exhibit good growth characteristics in vitro and in nude mice. Many marker chromosomes were detected. Histological examination and electron micrographs of B109 revealed at least two morphologically different subpopulations. The presence of steroid receptors and tumor associated antigens defined by monoclonal antibodies is discussed with regard to previously published results.

Animals↗
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Characterisation of a cell line from a human lung lymphosarcoma. Abundance of vimentin-type intermediate filaments.

A cell line (HCL82) was established from a human lung lymphosarcoma. Cells exhibited a stable phenotype and remained nearly diploid with a modal chromosome number of 45-48, showing no significant aberrations. Cultures consisted of single elongated cells and irregular colonies. Ultrastructurally, mitochondria, golgi complexes, and large bundles of intermediate filaments were well developed; some cells contained virus-like particles. Filaments were composed of vimentin identified by immunofluorescence and gel electrophoresis. Reaction with monoclonal antibody OKT4 suggested a close relationship to T-helper cells. Cells did grow at clonal density but did not form tumors in nude mice.

Animals↗
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[Group climate and therapist-patient relationship in two group therapy strategies for schizophrenic patients--a contribution to clarification of differential therapy effects].

A 5-year follow-up of 37 schizophrenic patients revealed that cognitive group therapy (CT) focused on optimum problem-coping skills led to a significant reduction in rehospitalisation, acute psychotic relapses and apathetic symptoms as compared with action-oriented group therapy (AT) directed towards improved social skills. This paper considers whether the group atmosphere and the therapist-patient relationship display important differences that might explain the divergent therapeutic outcomes of the two forms of group therapy. During half the group sessions, the AT patients felt better understood by their therapists than the CT patients. The AT patients were more emotionally involved during one third of the sessions than the CT patients. Towards completion of the therapy, they believed more strongly than the CT patients that they now had a better chance of solving their problems themselves and that they had learned more from their fellow-patients. In their relationships with the patients, the male At therapists felt more anxious, insecure and detached and inwardly less free than the male CT therapists. In contrast, the female AT therapists felt inwardly more free, empathetic and committed, and more confirmed in their relationship with the patients respect to their therapeutic method; the female CT therapists felt more uncertain and detached.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗