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Biomedical subjects

F J Rentsch

Publications and source records attributed to F J Rentsch.

17 recordsLinked to original sources
PubMed1982

Xeroderma pigmentosum patients from Germany: clinical symptoms and DNA repair characteristics.

Dermatologic, ophthalmologic, and neurologic examinations were carried out on 33 patients with clinical symptoms of xeroderma pigmentosum (XP). Complementation groups were determined for 23 patients. Types of tumors and complementation group were found to be related in the following way: In the XP variant groups basaliomas were the most frequently occurring malignant tumors, whereas in the D group pigmentary tumors, such as melanotic precanceroses and melanomas prevailed; in the A and the C group, spinaliomas seem to be the most frequent malignomas. The DNA repair activity was measured using colony-forming ability and unscheduled DNA synthesis. Colony-forming ability was quantitated as a function of 12 different UV doses and expressed in terms of D0. Unscheduled DNA synthesis was determined autoradiographically by establishing dose-response curves, which were analyzed by the characteristic value of linear regression. G0, defined as the linear increase in the mean number of silver grains per nucleus when the UV dose is multiplied by the factor of e (i.e., 2.72), was derived from the slopes of the regression lines. The repair capability of XP fibroblast lines was classified on the basis of D0 and G0.

Adolescent↗
PubMed1981

Electron microscopical aspects of acid compartments of the ground substance and of collagen in different cases of intravitreal tissue proliferation.

It is demonstrated that 'activated' glial cells or NPE cells are capable of producing small collagen fibrils of the vitreous type as well as basal lamina material. In contrast to this MRPE cells produce a different type of collagen, exhibiting a larger periodicity and larger diameters. Granular and fibrillar polyanionic materials are produced by the MRPE cells as well as by proliferating endothelial cells. The latter substances combined with the newly formed collagen of the MRPE cells in regular distances of about 460-480 A. The most characteristic feature of very young vascular buds is a multilaminar basal lamina, which is established long before a vascular lumen is formed. Collagen fibrils are absent in the early stages of neovascularization; however, they are abundant in more advanced stages. These observations may be helpful in situations where a reliable diagnosis in respect to the origin of a certain cell population is impossible because typical cell characteristics are absent or poorly developed.

Collagen↗
PubMed1980

[Cutaneous leishmaniasis (Oriental sore) of the lids (author's transl)].

After initial false diagnoses cutaneous leishmaniasis of the lids was diagnosed in a Portuguese woman and a Turkish man, both living and working in Germany. This paper describes the clinical pictures, histological and electron-microscopic findings in the two cases. Factors which may lead to false diagnosis are also discussed. It is pointed out that false diagnoses can be avoided best by taking a detailed and accurate history and identifying the pathogens as early as possible in smear cultures or by electron microscopy.

Adult↗
PubMed1977

The ultrastructure of preretinal macular fibrosis.

A case of preretinal macular fibrosis, following long-standing central vein occlusion and hemorrhagic glaucoma, was examined macroscopically and electron-microscopically. Pretreatment with cyclodiathermy puncture was performed twice before enucleation. The following morphologic results were observed: 1. Epiretinal cell layers in the peripapillar and foveolar regions which caused no 'puckering' of the retinal surface. These cell layers were mainly composed of glial cells. Some Müller cell processes and macrophages were also present. The epiretinal glial cells stem from the surface of the papilla and of the retina. They leave the retina through breaks of the basal lamina (especially where the latter is only a thin layer). 2. Folding (puckering) of the retinal surface was exclusively observed under condensed masses of fibrous tissue. The epiretinal fibrous tissue is composed of immature collagen fibrils of various diameters, of acid glycosaminoglycans, and of granular deposits of long-spacing collagen. The fibrillar material is firmly attached to the basal lamina of the retina. Shrinkage of the epiretinal fibrous tissue similar to the shrinkage of scar tissue is assumed to be the reason for the development of traction to the retinal surface. The epiretinal glial cells are assumed to be the sites of synthesis of the preretinal fibrous masses and glycosaminoglycans.

Aged↗