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Biomedical subjects

M Neumann

Publications and source records attributed to M Neumann.

At least 73 records · Page 4Linked to original sources
PubMed1987

Characterization of actinomycin-D-resistant CHO cell lines exhibiting a multidrug-resistance phenotype and amplified DNA sequences.

Actinomycin D (DACT)-resistant sublines of the Chinese hamster ovary cell line CHO-K1 were selected in vitro. Sublines were derived which expressed 5.2-fold (CHO 15DACT) and 35.8-fold (CHO 100DACT) resistance to DACT. The CHO 100DACT subline displayed marked cross-resistance to bleomycin, adriamycin, daunomycin, vinblastine, vincristine, VP 16 and VM 26. No cross-resistance was found to cisplatin or methotrexate. The resistant cells exhibited enhanced (collateral) sensitivity to prednisolone. Combination of prednisolone with vincristine resulted in a pronounced synergistic effect on sensitive cells, whereas in resistant cells the combined effect of both drugs was merely additive. Resistant cells, viably stained with the DNA-specific dye Hoechst 33342, exhibited decreased fluorescence intensities compared to parental cells. In contrast to sensitive cells the resistant sublines did not accumulate the mitochondria-specific dye rhodamine 123. Co-incubation with verapamil, however, effectively enhanced accumulation of the dye. The potential diagnostic value of these fluorescent compounds as marker dyes for the multidrug-resistance phenotype is discussed. Non-toxic doses of verapamil almost completely reversed the resistance to various drugs in CHO 100DACT cells. Specific DNA sequences were amplified in resistant cells, and the increase in resistance was paralleled by a concomitant increase in the copy number of these sequences, suggesting that the corresponding gene may be functionally linked to the multidrug-resistance phenotype.

Animals↗
PubMed1987

Cell length to diameter relation of rat fetal radial glia--does impaired K+ transport capacity of long thin cells cause their perinatal transformation into multipolar astrocytes?

In thick sections of Golgi-impregnated late fetal rat brains, radial glial cells were measured for both length and diameter of their main (basal) processes. The process diameter was found to decrease proportionally to the square root of cell length; thus, the cytoplasm volume remained fairly constant for cells in the range of lengths studied (100-2500 microns). The measured data were used for calculation of the cell's space constant lambda in order to estimate their capability to carry spatial buffering K+ currents. These calculations show that long and slender cells are unable to perform sufficient K+ clearance by such currents. This supports the hypothesis that perinatally when the maturing neurons release enhanced K+ during electrical activity, such long thin cells are subject to long-lasting depolarizations and, thereby, forced to undergo mitotic cell division transforming them into multipolar astrocytes.

Animals↗
PubMed1986

Interdependency of attitudes, diagnostic assessments and therapeutic recommendations of medical students towards mental patients.

Interdependencies of attitudes towards vignettes of mentally ill patients and the professional approach of medical students measured by means of diagnostic assessments and therapeutic distance were studied. First, the findings indicate that the attitudes towards the vignettes depended on the behavioral characteristics of each patient presented in the vignettes. Thus, the levels on four attitudinal subscales were different for each of the patients. Second, the two variables of the professional approach of the students towards the patients, i.e., the diagnostic assessment and the therapeutic distance, were dependent on the attitudes towards the patients. The findings indicate that the more disturbed a patient is, and the less he is diagnosed as mentally ill, the more he is rejected from treatment, and the more negative the students' attitudes are towards him.

Adult↗
PubMed1985

Morphological variability, lectin binding and Na+,K+-activated adenosine triphosphatase activity of isolated Müller (glial) cells from the rabbit retina.

Rabbit retinal Müller cells were isolated by means of papaine and mechanical dissociation. These cells were shown to have a well preserved morphology and to preserve viability for many hours. Intense wheat germ agglutinin binding occurs on the photoreceptor side of Müller cells, especially in the microvillous region. Rabbit retinal Müller cells have a Na+,K+-activated adenosine triphosphatase activity in the same order of magnitude as brain astroglial cells.

Animals↗
PubMed1985

Gradient separation of granulocytic progenitor cells (CFUc) from human blood mononuclear leukocytes.

Two different density-gradient techniques were compared for separation of human blood-derived granulocyte-macrophage progenitor cells (CFUc) from immunocompetent cells using albumin or Percoll as gradient media. Mean CFUc enrichment by means of discontinuous albumin gradient was twofold, whereas Percoll gradients yielded about 20- to 40-fold enrichment of CFUc in relation to lymphocytes. The pH of gradient media proved to have a major influence on separation quality. Based on these results and the development of a new density-separation technique in a 600-ml plastic bag, replacing customary Ficoll-Hypaque gradients, a method for large-scale purification of CFUc from leukapheresis-derived leukocytes has been constructed, working in a closed, sterile system. About 11 X 10(9) mononuclear cells containing 6 X 10(5) CFUc could be processed within 10 h. Lymphocytes were reduced to less than 1% of their initial number, and an average of about 50% of the original CFUc could be recovered.

Cell Separation↗
PubMed1984

[Effect and adverse effects of epidural anesthesia during labor. With special reference to changes in the cardiotocogram].

In an Obstetric Department with approximately 2,000 deliveries yearly, offry third mother is delivered under epidural anesthesia. In a group of 600 maternity patients, the effectiveness, the side effects and the changes in the fetal cardiotocogram were examined during labour and delivery under epidural anesthesia. Evaluated were questionnaire to the mothers with mainly subjective impressions, the anesthetic protocol, and the protocol of labour and delivery including the internal cardiotocogram. 85% of the mothers would have a future delivery under an epidural anesthesia. The incidence of headaches and its independence of the type of obstetric analgesia and anesthesia is mentioned. The number of punctures, the technique of epidural anesthesia, the concentration of the local anesthetic used, failures and side effects are described. The incidence of cesarian sections, fetal morbidity and changes in the cardiotocogram are discussed in detail. The incidence of transilent silent decelerations and alarm dips in the cardiotocogram are mentioned. This study shows that epidural anesthesia is free of risks and a highly effective method for the conduct of obstetric analgesia.

Anesthesia, Epidural↗
PubMed1983

[Chemotherapy of small cell carcinomas of the lung].

This report gives a comparison of two polychemotherapeutic regimen: Vincristin-Adriamycin-Cyclophosphamide (VAC) versus Vinblastin, Methotrexate, Fluoro Uracil, Cyclophosphamide (Israel-Karrer-Sighart regimen). 35 patients have been treated with VAC, 27 with IKS, some of them received additional irradiation. Response was quite similar in both regimens, survival was significantly increased for patients treated with VAC (49 weeks medial survival time versus 31 weeks). Best results were obtained in combination with intermittent radiotherapy (so called "sandwich-method"), survival time in this treatment had been 73 weeks. Side effects of the chemotherapy were tolerable and not severe. VAC in extensive disease alone and in limited disease in addition to radiotherapy can, therefore, be recommended in outdoor-patients treatment in small cell carcinoma of the lung.

Carcinoma, Small Cell↗
PubMed1983

Uterine motility after post-partum application of sulprostone and other oxytocics.

UNLABELLED: With the introduction of prostaglandins to obstetrics another group of substances was known to influence uterine motility also post partum. It was interesting to study the effect of equal doses of synthetic prostaglandin E2 (sulprostone), methergin and synthetic oxytocin on the so-called puerperal model in humans. By transcervically introduced twin-catheters uterine motility was recorded after uncomplicated pregnancy and delivery in 101 volunteers. Uterine motility was recorded and evaluated according to the onset of the effect, its duration, motility pattern and uterine activity. Maternal heart-rate was additionally recorded similarly to the feto-maternal cardiotocogram. All substances were applied by intramuscular injection. The following observations could be made: 1. Onset: sulprostone is effective in the shortest time, followed by oxytocin and methergin. 2. DURATION: the most prolonged effect is noticed with methergin, followed by sulprostone and syntocinon. 3. Motility pattern: the strongest effect can be seen with sulprostone, followed by methergin and syntocinon. 4. Increase of uterine motility was highest with sulprostone, followed by methergin and oxytocin. 5. No side-effects on the maternal heart-rate could be found with any of the tested substances. As a conclusion, sulprostone is recommended in the treatment of severe bleeding post partum when an immediate and long-lasting effect is to be achieved with one single substance.

Dinoprostone↗