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Biomedical subjects

B Ullrich

Publications and source records attributed to B Ullrich.

35 records · Page 2Linked to original sources
PubMed1993

Characterization of muscarinic receptors mediating vasodilation in rat perfused kidney.

The muscarinic receptor mediating vasodilation of resistance vessels in the rat isolated, constant-pressure perfused kidney (preconstriction by 10(-7) M cirazoline) was characterized by subtype-preferring agonists and selective antagonists. The agonists produced vasodilation with the following rank order of potency: arecaidine propargyl ester (APE) > 5-methylfurtrethonium = methacholine = oxotremorine > (S)-aceclidine > arecaidine 2-butyne-1,4-diyl bisester > 4-Cl-McN-A-343 = (R)-nipecotic acid ethyl ester = N-ethyl-guvacine propargyl ester approximately (R)-aceclidine = (S)-nipecotic acid ethyl ester > McN-A-343. Agonist-induced vasodilation disappeared after destruction of the endothelium with detergent. Highly significant correlations of agonist potencies for vasodilation were found between rat kidney and guinea-pig ileum submucosal arterioles as well as agonist potencies at smooth muscle muscarinic M3 receptors of the guinea-pig ileum. The rank order of antagonist potencies (4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) > (R)-hexahydro-difenidol approximately hexahydro-sila-difenidol > pirenzepine approximately p-fluoro-hexahydro-sila-difenidol approximately himbacine approximately AF-DX 384 approximately AQ-RA 741 > (S)-hexahydro-difenidol) to attenuate vasodilation to APE in rat kidney, correlated significantly with affinities at M3 receptors in submucosal arterioles and in smooth muscle of the guinea-pig ileum, but differed from those at M1 and M2 receptors in rabbit vas deferens. The agonist and antagonist potencies suggest that vasodilation elicited by muscarinic stimuli in endothelium-intact rat renal vasculature is mediated by functional muscarinic M3 receptors.

Animals↗
PubMed1993

Expression of the c-erbB-2-encoded oncoprotein and progesterone receptor in human meningiomas.

The present study investigated the expression of c-erbB-2 in 59 meningiomas, including different histological subtypes and anaplastic variants, by immunocytochemistry and molecular biological techniques. Immunohistochemistry using the monoclonal antibody FWP-51 directed against c-erbB-2-encoded oncoprotein gp185 demonstrated variable degrees of immunoreactivity in all meningiomas. The intensity of immunostaining correlated with the degree of expression as assessed by Western analysis in 28 meningiomas using polyclonal antiserum 21N. There was no correlation between the degree of expression and histological variants. Immunoreactivity of all meningiomas was distinctly less intense, however, than that of the human breast cancer cell line SK-BR-3, and slightly lower than that of brain metastases of breast and ovarian carcinomas that served as positive controls for both methods. By Southern analysis all meningiomas showed a single copy of the c-erbB-2 gene. Non-neoplastic arachnoid cap cells also exhibited c-erbB-2 expression and the degree of immunoreactivity was comparable with the majority of meningiomas. These data argue against an overexpression of c-erbB-2 in meningiomas, but rather indicate a cell-type-specific constitutive expression of the c-erbB-2 gene product in meningiomas and their putative progenitor cells. Since a subgroup of meningiomas is known to express progesterone receptors (PR), gp185 immunoreactivity was compared to the hormone receptor status using monoclonal antibody KD68. Fifty-six percent meningiomas showed PR immunoreactivity, but there was no statistically significant correlation with the degree of gp185 expression.

Adult↗
PubMed1991

Three-dimensional time-of-flight MR-angiography and the surgical indication of brainstem cavernomas.

This study was designed to assess the diagnostic value of 3D time-of-flight MR-angiography in cerebral cavernomas. In seven patients, nine out of ten cavernomas were removed by microsurgery. While MR-angiography demonstrated well branches of brain arteries adjacent to the lesions, no flow signal in the vascular malformations was observed. On the other hand, there was a high intensity signal induced by methaemoglobin in those three patients with brainstem cavernomas who had experienced a significant bleeding attack seven months prior to admission. It had a spotted appearance in MR-angiography with volumes of the largest spots around 1.8 cm3. It is suggested that this spot signal could be used as a path marker for the surgical approach in brainstem cavernomas.

Adult↗
PubMed1989

[Effect of surface treatment and thermal stress on the adaptation of Germadent amalgam fillings].

Surfaces of amalgam-fillings (Germadent) applied to extracted human teeth were treated in four variants. The adaptation of the fillings to the cavosurface margins was measured with SEM before and after thermal stress. Burnishing lead to a clear reduction of leakages, in contrast to carving. Fillings polished after carving, and especially after burnishing, have smallest marginal leakage. Thermal charges cause a small deterioration of marginal adaptation.

Alloys↗
PubMed1986

Ouabain enhances release of acetylcholine in the heart evoked by unilateral vagal stimulation.

The aim of the study was to elucidate peripheral effects of ouabain on the parasympathetic innervation of the heart, effects that could contribute to the experimentally and clinically well established "vagal effect of cardiac glycosides". The experiments were carried out with ouabain concentrations of 3 X 10(-7) and 10(-6) mol/l, which were considered "therapeutic", as they increased force of contraction and did not elicit arrhythmias in incubated chicken atria. In atrial preparations of chickens and guinea-pigs the negative chronotropic and inotropic effects of acetylcholine (ACh) were not altered by 3 X 10(-7) mol/l ouabain. Resting efflux of ACh from perfused chicken hearts was increased by ouabain from 10 to a maximum of 30 pmol/g min, whereas release of ACh evoked by bilateral vagal stimulation at 3 or 20 Hz for 1 min was unchanged (resting release subtracted). In contrast, release of ACh caused by unilateral vagal stimulation was augmented by ouabain up to 200% of the control. Release by unilateral stimulation (80 pmol/g; 20 Hz) was calculated for each experiment by averaging the releases evoked by consecutive stimulation of the right and left nerves. Ouabain infused for 90 min did not alter the tissue content of ACh (5.5 nmol/g). Within 2 days after unilateral (left) vagal transsection (denervation of cardiac ganglia) the release of ACh evoked by stimulation of the intact nerve (20 Hz) increased from about 80 to 200 pmol/g, whereas the release from the lesioned nerve markedly declined.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1982

[The influence of chronic relapsing infections of the air passages on the subpopulations of peripheral blood lymphocytes in children with atopic diseases (author's transl)].

In 68 children with atopic diseases and 42 controls of the same age, the authors conducted lymphocyte differentiation examinations. The T-lymphocytes were determined by means of the E-rosette technique, whereas the B-cell counts were determined via monospecific fluorescein-marked anti-immunoglobulin sera. The entire group of juvenile atopics was separated into one group with massed infections and another group without susceptibility to infection. The group of children without susceptibility to infection concomitant with existing atopy, showed significantly relative T-lymphocyte counts, compared with the control group, the relative and absolute counts of the other lymphocyte subpopulation being normal. In the group of juvenile atopics with a pronounced tendency to infection, the T-cell deficiency and normal absolute T-lymphocyte counts are even more conspicuous, whereas the B-cell and O-cell counts are higher than with the control group. It is possible to identify the influence of chronic relapsing infections on the lymphocyte subpopulation in atopics. The article discusses the problem of the type of cellular immunodefect in atopic children without previous history of an infection.

Adolescent↗
PubMed1976

The effect of continuous exposure to low frequency electric fields on three generations of mice: a pilot study.

Mice were allowed to mate, gestate, deliver and rear their offspring for 3 successive generations while being continuously exposed to 60 Hz electric fields. Mice exposed to vertical electric fields exhibited decreased body weights at 35 days postpartum and increased mortality rates for 3 successive generations. Mice exposed to horizontal electric fields exhibited decreased body weights for 2 successive generations.

Animals↗