Search PubMed⌕ Search

Biomedical subjects

W Hanke

Publications and source records attributed to W Hanke.

186 records · Page 11Linked to original sources
PubMedDate not supplied

Angiotensin II binding sites in frog kidney and adrenal.

Angiotensin II (AII) binding sites were localized and quantified in kidney and adrenal of the frog Rana temporaria by quantitative in vitro autoradiography. AII binding was present in kidney glomeruli and in interrenal tissue of the outer zone of the adrenal gland. Saturation experiments showed that [125I]-[Val5]AII binds to a single class of binding sites with a dissociation constant (Kd) of 548 +/- 125 pM in glomeruli and 593 +/- 185 pM in interrenal tissue (n = 8). The corresponding maximal binding capacities (Bmax) were 2.48 +/- 0.71 and 3.05 +/- 1.02 fmol/mm2, respectively. AII binding was displaced by unlabeled angiotensin analogues in the rank order: [Sar1]AII greater than human AII greater than [125I]-[Val5]AII = [Val5]AII = human AIII much greater than human AI. The AII binding sites in glomeruli and interrenal tissue suggest an influence of AII on glomerular filtration rate and adrenal steroid secretion to take part in osmomineral regulation of the frog.

Adrenal Glands↗
PubMedDate not supplied

Channel properties of an insect neuronal acetylcholine receptor protein reconstituted in planar lipid bilayers.

A pentameric membrane protein composed of four types of polypeptide has been identified as the minimal structural unit responsible for the electrogenic action of acetylcholine on electrocytes and muscle cells. Because many populations of central and peripheral neurons also have nicotinic acetylcholine receptors (AChRs), considerable effort has recently gone into identifying the neuronal receptor. The central nervous tissue of insects contains very high concentrations of nicotinic AChRs, and we have recently purified an alpha-toxin binding protein, a putative AChR, from neuronal membranes of locusts. It is a component of high relative molecular mass, clearly composed of identical subunits, a structure predicted for an ancestral AChR protein. To verify that the purified polypeptides not only represent ligand binding sites but that they are indeed functional receptors, we have now reconstituted the isolated protein in a planar lipid bilayer. We show that in this system cholinergic agonists activate functional ion channels, that have properties comparable to those exhibited by the peripheral AChRs in vertebrates; thus, for the first time a functional acetylcholine receptor channel has been identified in nerve cells.

Acetylcholine↗
PubMedDate not supplied

A re-evaluation of radiological evidence from a study of U.S. strip coal miners.

In 1972, the U.S. Public Health Service examined 1438 workers employed at seven bituminous and one anthracite U.S. strip coal mines. One conclusion from the study was that workers without previous dust exposures were not at risk of category 2 or higher pneumoconiosis from their strip coal mining environment. Because of recent concerns for silicosis among strip coal miners, the radiographs were reinterpreted and the data re-evaluated. In addition, data from respirable coal mine dust samples collected from 1972 to 1979 in all surface coal mines were analyzed. The results showed that category 2 or higher pneumoconiosis was prevalent among strip coal miners with experience in an underground coal mine. Among those without underground coal mine experience, category 2 or higher was prevalent among anthracite strip miners, but not among bituminous strip miners. Average respirable coal mine dust exposures in the anthracite mine were less than 1 mg/m3 prior to 1975 and, coupled with the radiographic findings, suggest further study of the efficacy of the 2 mg/m3 U.S. Federal surface coal mine dust standard in anthracite coal mines.

Coal Mining↗
PubMedDate not supplied

Prototype breast coil for MR-guided needle localization.

OBJECTIVE: Evaluation of breast lesions detected by MR alone is a problem: Preoperative MR-guided localization is difficult, since the breast is not accessible by a needle within the breast coil. Magnetic resonance-guided core biopsy and needle aspiration are impossible. Together with Siemens Erlangen, a prototype localization breast coil has been developed and tested. MATERIALS AND METHODS: The device consists of a circular polarized coil, which contains two plates for mediolateral breast compression. They are perforated with numerous holes and thus allow access to the breast from both sides. By means of bushings, which fit into the holes, sterile needle insertion in a horizontal path is possible. RESULTS: So far, precise needle insertion has been possible in 10 of 11 lesions, allowing exact needle insertion into 5 invasive carcinomas (1 MR-detected), 1 MR-detected additional focus, 2 in situ carcinomas (1 MR-detected), and 3 benign lesions. CONCLUSION: Our studies show that MR-guided needle localization is possible.

Aluminum↗
PubMedDate not supplied

Association between abnormal microbiological flora of the lower genital tract in early pregnancy and socio-economic, demographic and environmental risk factors.

BACKGROUND: The main aim of this study was to determine the socioeconomic, demographic and environmental factors which may be associated with the occurrence of pathological microflora of the lower genital tract in early pregnancy. MATERIAL AND METHODS: A group of 96 pregnant women was selected at random from the patients of 10 district maternity units in the Lodz region of Poland. Only singleton pregnancies below 24 weeks were qualified for inclusion in the survey. A standard questionnaire covering medical, socio-economic, demographic, constitutional, and environmental items was administered to every subject and checked against medical records. Based on microbiological results, two groups of pregnant women were distinguished: Group I, with normal cervicovaginal flora, predominantly Lactobacillus spp. with coagulase-negative staphylococci and viridans streptococci, and Group II, with abnormal flora. The latter included two subgroups: IIA, intermediate microbial flora, dominated by M. hominis, U. urealyticum, G. vaginalis, gram-negative anaerobic rods, Ch. trachomatis, and few Lactobacillus spp, and IIB, highly abnormal flora, containing similar microbial components as in IIB but without Lactobacillus spp. RESULTS: Based on the results of microbiological culturing, 18 (18.7%) of the 96 women examined were classified to Group I, and 78 (81.2%) to Group II: 32 (33.3%) in group IIA and 46 (47.9%) in IIB. Groups IIA and IIB were combined for further analysis. An excessive risk of abnormal vaginal flora was observed in connection with such socio-economic factors as marital status, unemployment, and smoking, Moreover, the first pregnancy was also found to be a potential risk factor for this pathology. The risk of developing abnormal vaginal flora, although exceeding unity for each of these factors, was not considered statistically significant. CONCLUSIONS: Socio-economic and environmental factors may influence the course and outcome of pregnancy. Pregnant women who present with risk factors for abnormal cervicovaginal microflora should be included in comprehensive prenatal surveillance, which enables early detection and treatment of this pathology.

Bacteria↗