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Biomedical subjects

S Zimmer

Publications and source records attributed to S Zimmer.

At least 73 records · Page 4Linked to original sources
PubMed1991

The effects of shear stress and metastatic phenotype on the detachment of transformed cells.

A parallel-plate flow chamber was used to quantify the detachment of normal, transformed, and reverted rat fibroblasts from a confluent monolayer of normal fibroblasts. In this method, known shear stresses were applied to the adherent cells and the percent of cells detached from the monolayer was determined. Results indicate that the detachment of all cell types increased with increasing shear stress and detachment of highly metastatic ras-transformed cells was significantly higher than that of either nonmetastatic normal cells or transformed cells reverted with the Kirsten ras revertant (K-rev 1a) gene, which are lowly metastatic. From these results, it is concluded that a correlation exists between the metastatic phenotype of the cell and its ability to detach from normal cells.

Animals↗
PubMed1991

Viscoelastic properties of transformed cells: role in tumor cell progression and metastasis formation.

The micropipette aspiration technique was used to investigate the deformation properties of a panel of nontransformed and transformed rat fibroblasts derived from the same normal cell line. In this method, a step negative pressure is applied to the cell via a micropipette and the aspiration distance into the pipette as a function of time is determined using video techniques. A standard solid viscoelastic model was then used to analyze the viscoelastic properties of the cell. From these results, it is concluded that a direct correlation exists between an increase in deformability and progression of the transformed phenotype from a nontumorigenic cell line into a tumorigenic, metastatic cell line.

Animals↗
PubMed1991

[Cytology of bacterial vaginosis].

Bacterial vaginosis seems to be one of the most frequent cause of vaginal diseases which may be ascending and separates a not aesthetical discharge. A pH greater than 4.5 is found, the presence of clue cells, and a positive sniff test referring to Mobiluncus. The main microorganisms causing bacterial vaginosis are Gardnerella vaginalis and Mobiluncus sp. These are anaerobic ones. Cytology is able to give a quick and sure diagnosis.

Colposcopy↗
PubMed1990

Effects of adenosine on human coronary arterial circulation.

Adenosine is a potent vasodilator used extensively to study the coronary circulation of animals. Its use in humans, however, has been hampered by lack of knowledge about its effects on the human coronary circulation and by concern about its safety. We investigated in humans the effects of adenosine, administered by intracoronary bolus (2-16 micrograms), intracoronary infusion (10-240 micrograms/min), or intravenous infusion (35-140 micrograms/kg/min) on coronary and systemic hemodynamics and the electrocardiogram. Coronary blood flow velocity (CBFV) was measured with a 3F coronary Doppler catheter. The maximal CBFV was determined with intracoronary papaverine (4.5 +/- 0.2.resting CBFV). In normal left coronary arteries (n = 20), 16-micrograms boluses of adenosine caused coronary hyperemia similar to that caused by papaverine (4.6 +/- 0.7.resting CBFV). In the right coronary artery (n = 5), 12-micrograms boluses caused maximal hyperemia (4.4 +/- 1.0.resting CBFV). Intracoronary boluses caused a small, brief decrease in arterial pressure (similar to that caused by papaverine) and no changes in heart rate or in the electrocardiogram. The duration of hyperemia was much shorter after adenosine than after papaverine administration. Intracoronary infusions of 80 micrograms/min or more into the left coronary artery (n = 6) also caused maximal hyperemia (4.4 +/- 0.1.resting CBFV), and doses up to 240 micrograms/min caused a minimal decrease in arterial pressure (-6 +/- 2 mm Hg) and no significant change in heart rate or in electrocardiographic variables. Intravenous infusions in normal patients (n = 25) at 140 micrograms/kg/min caused coronary vasodilation similar to that caused by papaverine in 84% of patients (4.4 +/- 0.9.resting CBFV). At submaximal infusion rates, however, CBFV often fluctuated widely. During the 140-micrograms/kg/min infusion, arterial pressure decreased 6 +/- 7 mm Hg, and heart rate increased 24 +/- 14 beats/min. One patient developed 1 cycle of 2:1 atrioventricular block, but otherwise, the electrocardiogram did not change. In eight patients with microvascular vasodilator dysfunction (delta CBFV, less than 3.5 peak/resting velocity after a maximally vasodilating dose of intracoronary papaverine), the dose-response characteristics to intracoronary boluses and intravenous infusions of adenosine were similar to those found in normal patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine↗
PubMed1989

[Public education in recognizing melanoma].

We report on the first German "melanoma screening week" (Offenbach Melanoma Week). According to the model of the Melanoma/Skin Cancer Detection Week in Dayton/Ohio, the population of Offenbach (100.000 inhabitants) were informed about cutaneous malignant melanoma and its early recognition by means of public media, in particular the local press; the people were asked to participate in a voluntary screening including examination of the entire skin. These examinations were offered in 5 local dermatological practices on 5 working days during the European Week Against Cancer in May, 1988, under the auspices of the Hessian Cancer Society. With 2 to 4 dermatologists daily volunteering, a total of 697 persons were screened. Their average age was 48 years. An illustrated brochure ("Red Light for Black Cancer") with instructions for self-examination of the skin served as a consultation basis and memory aid. The screening week was concluded by a 3-hour's question time ("The citizen asks - the expert answers"). The most surprising result of this campaign was the fact that - contrary to earlier experience - 76% of the persons seeking advice were well aware of "black" cancer. The sole new melanoma detected was an extended lentigo maligna melanoma on the right cheek, which had not been noted during a prophylactic medical examination (!) 2 weeks before. The high public awareness of melanoma and the extremely low percentage of undetected melanomas in Hesse are most probably the result of the 8-year's educational campaign against "black" cancer.

Germany, West↗
PubMed1989

Hypoxic pulmonary vasoconstriction is unaltered by creatine depletion induced by dietary beta-guanidino propionic acid.

It has been suggested that a specific phosphagen pool might serve a sensor function, allowing direct detection of alveolar hypoxia by the pulmonary vascular smooth muscle. The possibility that phosphocreatine (PCr) levels could serve as such a sensor was assessed in isolated rat lungs. Pulmonary vascular reactivity to angiotensin II and alveolar hypoxia was assessed in lungs from control and PCr-depleted rats. PCr depletion was accomplished by feeding rats a diet containing 2% beta-guanidino propionic acid (beta-GPA), an competitive inhibitor of creatine uptake. Total creatine was depleted in beta-GPA lungs, compared to control lungs (p less than 0.05). Lung PCr levels were undetectable by the available 31P NMR spectroscopy system. PCr and creatine were depleted in hearts from beta-GPA rats relative to control hearts (p less than 0.001). Normoxic pulmonary artery pressure and the pressor responses to angiotensin II and hypoxia were not qualitatively or quantitatively altered by the diet indicating either that PCr is not a critical participant in hypoxic pulmonary vasoconstriction or that the degree of PCr depletion achieved was inadequate to expose its role in the hypoxic pressor response.

Animals↗
PubMed1989

Isolation and immunological characterization of a group of new B lymphomas from CBA mice.

We have isolated and characterized a new series of B lymphoma which occurred spontaneously in a group of CBA/N mice that were transferred with spleen or lymph node cells from 24-month-old CBA/Ca mice. Tumor cell lines from six CBA/N mice that received spleen cells were rescued and designated as BKS-2, BKS-3, BKS-4, BKS-5, BKS-6, and BKS-7. Also, tumor cells from a recipient of lymph node cells were rescued and the resulting cell line was designated BKL. These tumor cells expressed membrane immunoglobulin (mu, kappa), major histocompatibility complex Class I and Class II molecules, B220, Lyb8, Fc receptors, J11d, interleukin 2 receptors, and Ly1. All of the tumors did not express the T cell specific markers Thy 1.2, L3T4, and Lyt2.1. They appeared to be clonal in origin, since they exhibited common rearrangements at both heavy and light chain immunoglobulin loci. Phenotypically, these lymphomas appeared to be analogous to immature B cells. Also, these lymphomas displayed different functional reactivities when treated with various B cell mitogens and growth factors in vitro. Anti-mu antibodies which normally induce B cell growth inhibited the proliferation of these lymphoma cells in vitro, whereas they responded to lipopolysaccharide, T cell-derived growth factors, and interleukin 5 by enhanced proliferation. These tumor cells expressed constitutively high levels of c-myc mRNA.

Animals↗
PubMed1989

Cuff herniation.

Explore the source record for details and available documents.

Equipment Failure↗
PubMed1989

[Cyto- and histomorphologic changes in the Jensen sarcoma exposed to cisplatin, radiotherapy and combination treatment].

Puncture-cytological and histomorphological investigation results are presented in transplanted tumor Jensen sarcoma. The tested tumors did not respond to therapy in growth reaction and reached a quarter of the body mass of the experimental animals on day 18 post transplantation. Within the five groups (untreated, cisplatin daily 0.6 mg/kg b.w., irradiated with 2 Gy S. D., 20 Gy T. D. only, and 2 groups combined therapy cisplatin and irradiation) cytological differences were shown between the several therapeutic groups already at therapy day 7 in spite of similar growth reaction, but not between centre and periphery of tumors, that were marked more distinctly and confirmed in histomorphological picture at the end of therapy at day 18 p.t. The increased occurrence of giant cells with many nuclei and leukocytic inflammation reaction seem to be a typical picture for combined therapy.

Animals↗
PubMed1987

[Significance of sources of error and quality control in cytologic mass screening].

The cervical mass screening programme in the GDR (since 1973) indicates a high degree of participation exhibiting a sufficient specificity. The sensitivity however has to become better. The main cause of false negative diagnoses is the insufficient gaining materials from the endocerrix channel. This may be corrected by a new plastic spatula. Both the consequent education of the prescreeners and collective final diagnoses may give further help to reduce cytological false negative diagnoses. False positive diagnoses are less fatal. They may be corrected by repeated controls, by special consultations, and by histology.

Cervix Uteri↗
PubMed1986

Induction of the c-myc protooncogene after antigen binding to hapten-specific B cells.

The stimulation of hapten-specific B cell populations with the thymus-dependent antigen, TNP-KLH, was found to induce elevated levels of c-myc mRNA by 2 h. A similar treatment with carrier protein alone did not elevate c-myc mRNA above the level seen in the nonstimulated, resting B cells. These results indicate that antigen binding to the sIg receptor, in the absence of Th cell involvement, directly signals the antigen-binding cell and implicates the active participation of sIg during the process of antigen-mediated B cell activation.

Animals↗
PubMed1984

[Apudomas of the lung from the cytochemical and electron microscopic viewpoint].

12 small cell anaplastic carcinomas and two bronchial carcinoids have been analysed by light and electron microscopy. Using cytological smears from tumor materials (imprints) silver stainings were applied for detection of argyrophilic and argentaffin nature of APUDoma (Fontana-Masson, Grimelius). The results were compared with ultrastructural findings of neurosecretory granules.

Adult↗