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Biomedical subjects

W Wolff

Publications and source records attributed to W Wolff.

At least 19 recordsLinked to original sources
PubMed1999

[Histological biomorphosis of human heart valve. II. Morphometric studies].

Previous polarization-microscopical measurements combined with silver-staining methods at histological sections of the bicuspid valve and the tricuspid valve in the region of fibrosa showed (similar to that of the corresponding tendinous cords) for middle-aged persons a distinct difference in the collagen composition in comparison between high pressure vs. low pressure system. The aim of the current study was the morphometric investigation of the collagen composition, of the relative content of total collagen (measured as relative number of total collagen fibers per measuring area), and of the cell-collagen relation in dependence of age and possibly on sex in the high and low pressure system, respectively. Tissue samples of atrioventricular valves of 67 probands of both sexes were available. The probands were healthy with regard to heart and circulation and distributed in 3 age groups (1st to 2nd decade, 3rd to 5th decade, and 6th to 9th decade). After corresponding preliminary treatment, the histological sections of tissue samples were evaluated by a suitable combination of polarization-microscopical, immuno-histochemical, and morphometrical methodology. The thickness of the heart valves was measured by microscopic image analysis. A rise of the number of fibers per measuring area (ma) for both sexes and both valves was observed with increasing age. The slopes of the linear regression curves and the mean values of the numbers of collagenous fibers/ma (for each age group) were different between both sexes. They depend upon the valve considered. Analogous to these results, the differentiated statements were possible to the number of fibers/ma and to the percentages of the fiber species by the distinction between the collagen types I and III in the fibrosa of the heart valves. Whereas the relative numbers of fibers/ma rose with increasing age, the number of cell (fibroblasts, fibrocytes) nuclei for both valves and sexes slightly decreased. For the latter, there was no difference between high and low pressure system in contrast to the collagenous fibers. The opposite age-dependent behavior of the collagenous fibers and of their producing cells during the biomorphosis of the heart valves could be explained with the collagen turn-over.

Adolescent↗
PubMed1990

[Epidemiological profile of dental caries and treatment needs].

In a population survey 2,263 patients were examined for their caries status and treatment needs. The DMF/T-Index and the individual relative risk for caries were calculated. Adolescents and young adults showed a high caries risk and required most of all necessary restorations. But especially older adults and seniors over 55 years presented a high caries risk, required more extensive restorations and more public dental health care at all.

Adolescent↗
PubMed1990

Changes in the distribution of proteinpolysaccharide complexes within the articular cartilage in experimental osteoarthrosis.

The quantity and type of proteinpolysaccharide complexes in the matrix determine up to a great extent the mechanical properties of articular cartilage. It is the purpose of this study to evaluate the changes in the mentioned matrix components against the background of experimentally induced osteoarthrosis. As shown by electron microscopic and morphometric studies, the changes in the superficial layer are promptly occurring and clearcut, whereas those in the deep layers are recorded in late observation terms only. A reduction of proteoglycan quantity is noted with a simultaneous differentiation of their fine structure in the various stages of osteoarthrosis development. Initially the alteration in the cell organization of chondroblasts is associated with occurrence of differences in proteoglycan content, and subsequently--in the collagen structures of the matrix too.

Animals↗
PubMed1990

[Estimation of the healing process of denatured orthotopic bone implants in an animal model. I. Measurements with polarization microscopy].

The paper gives in a series of 3 parts a survey, quantitative statements and conclusions on the healing process of denatured orthotopic osteoresections with the initial bone obtained by, polarization optical measurements (this first part), morphological evaluation method (part II), (in these cases the collagen polymorphism served as indicator for the regeneration course) and, semiquantitative method of observation after conventionally histological treatment as well (part III). The investigations were carried out on the mandible of pigs depending on the treatment of the resected bone parts (chemical or hyperthermal denaturation in comparison with the native state). Samples of osteoreimplantions were taken in intervals of one week up to the 70th postoperative day. Histological sections were used from the different regions (contact region, gap region, border and internal regions of the resections) and investigated by the methods mentioned above. The results of the first part (polarization microscopical measurements) revealed the regular course of differentiation in the bone regeneration process: The resection is fully integrated into the initial bone after a mean duration of 112 +/- 25 days. The fastest regeneration takes place in the contact region, the slowest is found within the resection (in the case of chemical denaturation investigated).

Animals↗
PubMed1984

Direct radioimmunoassay of antibody against hepatitis B core antigen using 32P-labelled core particles.

A direct radioimmune assay for antibody against hepatitis B core antigen (HBcAg) was developed. Flexible microtiter plates were coated with HBcAg, incubated with test samples, and thereafter with 32P-labelled HBcAg. Labelling was achieved by endogenous protein kinase of the core particles. This assay was tenfold more sensitive than a conventional inhibition assay employing enzyme-labelled anti-HBc as reagent. The radioimmunoassay detected a large number of positive persons (88/200) in a population with a high prevalence of blood-transmitted hepatitis infections (medical staff, liver and dialysis patients, contact persons, implicated blood donors) which were not detected by the inhibition assay. Such results were rare in healthy blood donors. The weak anti-HBc activity, which was detected only by direct radioimmunoassay, co-purified with IgG and was inhibited by addition of HBcAg to the serum. The activity may be due to a very limited hepatitis B infection or, what is more likely, to cross-reacting antibodies against unknown antigen(s). The factor detected only by direct radioimmune assay appears to be related to viral hepatitis. For detection of anti-HBc as a marker for hepatitis B virus it is, however, preferable to use less sensitive assays.

Hepatitis B Antibodies↗
PubMed1982

Specificity and localization of the hepatitis B virus-associated protein kinase.

The nature of the protein kinase (PK) which phosphorylates the core protein of hepatitis B virus in vitro was studied. The PK copurified with the core particles during rate zonal centrifugation and gel chromatography. It showed the same size heterogeneity as the core particles, which consisted of a main fraction of 28-nm particles and a subfraction of 22- to 26-nm particles. DNA-containing heavy core particles with a density of 1.33 to 1.35 g/ml and less endogenous PK than did the light cores. The phosphorylation reaction had a rapid initial phase (several minutes) and a slow but long-lasting second phase (many hours). The PK had a high affinity for ATP (KM = 0.5 mumol/liter). Only few of the several hundred P21.9 subunits in one core particle were phosphorylated in vitro. The only amino acid which was phosphorylated in vitro was serine. The resistance of the introduced phospho group against alkaline phosphatase showed that the PK acceptor, and probably the enzyme itself, was located inside the core particle.

Adenosine Triphosphate↗
PubMed1979

[Synthesis of the fragments A1-8, A1-7, A9-15 and A8-15 of the chicken insulin A chain (author's transl)].

By coupling the peptide derivatives H-Cys(SBut)-Cys(SBut)-His-OMe(6-8 b) and H-Cys(SBut)-Cys(SBut)-OH(6-7b) respectively with Trt-Gly-Ile-Val-Glu(OBut)-Gln-OH(1-5a) the N-terminal sequences A1-8 and A1-7 of the chicken insulin A chain have been prepared. The sequence of A9-15 has been obtained by connecting Bpoc-Asn-Thr(But)-Cys(SBut)-OH (9-11c) and H-Ser(But)-Leu-Try(But)-Gln-OH (12-15). Acylation of the aminopeptidderivative 9-15b with Bpoc-N2H3 yielded fragment A8-15 (8-15).

Animals↗
PubMed1976

Flexible colonoscopy.

Colonoscopy with fiberoptic instruments has opened new vistas in diagnosis and treatment of colonic disease. Such endoscopy requires skill, experience, and judgment to be accomplished readily and safely but permits visual examination of the entire colon and, frequently, the terminal ileum as well. Although in experienced hands colonoscopy may have greater diagnostic accuracy than the barium enema, particularly with respect to colorectal cancer and polyps, the two are complementary modalities and with their combined use an extremely high rate of detection and confirmed diagnosis can be expected. The Beth Israel group introduced the technique of snare-cautery removal of colonic polyps via the colonoscope and has now successfully resected over 2500 such polyps without a single death. This is the largest world experience. Selected polyps can be removed endoscopically as an ambulatory procedure, reducing costs and incapacitation time. Neoplastic polyps often harbor invasive cancer and their extirpation is expected to reduce the incidence of overt colorectal cancer. Colonoscopy and endoscopic polypectomy offers the opportunity to check the rising incidence, morbidity, and mortality related to colorectal cancer.

Adenoma↗