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Biomedical subjects

H Wehner

Publications and source records attributed to H Wehner.

At least 19 recordsLinked to original sources
PubMed1991

Morphometric investigations on intrarenal vessels of streptozotocin-diabetic rats.

We have investigated 975 different grazing sections of vessels in kidney preparations of 20 rats of the Wistar strain. Half of these genetically identical animals had an insulin-deficiency diabetes induced by injection of streptozocin. The kidneys were removed for investigation after 2 and 12 weeks duration of diabetes. The vessel cross-section, wall, lumen and endothelial surface area were determined in renal arteries, arterioles and preglomerular afferent arterioles in a blind experiment. Statistically detecteable changes were found in the diabetic vessels in the early stage of the diabetes. Preglomerular afferent arterioles showed a highly significant and increasing lumen dilatation commencing after 2 weeks. Diabetic arteries and arterioles developed narrower lumina. A significant thickening of the endothelium took place at the same time in both vessel types. All three vessel regions became smaller and had thinner walls than healthy vessels as the diabetes progressed. The findings on the afferent vessels indicate that haemodynamic effects on the glomerulus are to be expected. Familial diabetic gloermulopathy begins with a reversible hyperfiltration. However, the mechanism has not been clarified in the context of the diabetic metabolic disorder, and this change is probably the haemodynamic consequence of the substantial dilatation of the preglomerular afferent arterioles. With their renin-positive segment, these arterioles are the centre of intrarenal regulation. The increase of the capillary glomerular pressure associated with the dilatation of the preglomerular afferent arterioles is a crucial factor in the development of diabetic glomerulopathy.

Animals↗
PubMed1991

[Role of steroid hormones and related biological substances in the etiology of endometrial carcinomas].

Synthetical oestrogens, as well as gestagens may cause metaplastic changes of the endometrial epithelia. While squamous and tubal metaplasia are most often due to oestrogenic stimulation and develop in hyperplastic endometria, mucinous and clear cell metaplasia are stimulated by gestagens and tamoxifen. Tamoxifen seems to act gestagen-like on the endometrium. We present data of 31 patients, who were treated with tamoxifen for breast cancer disease. 3 of these 31 developed endometrial adenocarcinoma.

Adenocarcinoma↗
PubMed1990

[Fundamental research in ultrasonic surgery. IX. Splenic surgery using cavitation ultrasound--an experimental animal study of aspiration and sealing technics with ligament FIMOMED].

A farther alternative for the conservation of the spleen represents the ultrasonic aspiration and sealing technique by means of the monomeric tissue adhesive Ligament Fimomed. The effectiveness of the method was proved by histomorphologic investigations in animal experiment with the porcine spleen. The method was effective in nearly all injuries across to the longitudinal axle of the organ even with a larger parenchymal defect and also in case of splenic tumor. The control of hemorrhage succeeded promptly and surely. Not any postoperative complication appeared.

Animals↗
PubMed1989

Biodegradation of crude oils.

Petroleum from well sites in the Gifhorn Trough (Lower Saxony, NW-Germany) and the Maracaibo Basin (Venezuela) contained various types of microorganisms capable of degrading crude oils. Genetically related oils were inoculated with the isolated microorganisms and the degradation of the oils was followed by chromatographic techniques. Parameters important for the reactions (pH, supply of oxygen, nitrogen and phosphorus, reaction medium) were monitored and optimized. The degradation of n-alkanes was followed closely. Microorganisms active in degradation (yeast, bacteria) easily survived a period of inactivity due to missing nutrients and were reactivated within hours to degrade newly added crude oil. Under substrate-limiting conditions selectivity of degradation was found, destroying medium-chain n-alkanes (C20, C21) at a faster rate than long-chain n-alkanes (C30, C31). During degradation the physical parameters of the crude oils (e.g. density, viscosity, average molecular weight) were altered and shifted into the direction of heavy oil. In vitro degraded oil is very similar to oil degraded in nature. Aromatic hydrocarbons and biomarker molecules (steranes and triterpanes) were not degraded under the conditions used. Pyrolysis-GC analysis of asphaltenes revealed no significant changes in the composition of pyrolyzates during biodegradation. There is sufficient evidence that heavy oils - besides some other effects - are generated by the in situ-biodegradation of conventional oils.

Alkanes↗
PubMed1986

Renal vessel changes in diabetic KK-mice.

Glomerular hyperfiltration is thought to be of pathogenic importance in the structural abnormalities seen in diabetic nephropathy but its cause is not known. It has been suggested that the changes in the preglomerular vascular system may lead to a disturbance of glomerular blood flow in diabetes. We therefore examined the potential role of changes in the vascular system supplying the glomerulus in diabetic mice. The kidneys of 15 diabetic KK-mice (aged 2, 5 and 12 months) were studied and compared with those of 15 non-diabetic NMRI-mice. We determined vessel cross-sectional, wall and lumen areas of 408 small intrarenal arteries, 5,140 arterioles and 518 preglomerular afferent arterioles using a morphometric method. At 2 months, diabetic arteries and arterioles were considerably smaller than the controls, while preglomerular afferent arterioles were the same size. At 12 months, however, all diabetic vessels measured were much larger than the controls. This was chiefly due to an excessive increase in lumen area: in the diabetic arteries the mean (+/- SEM) lumen area at 12 months was 1,057 +/- 142 vs 616 +/- 72 sq mu in controls (P less than 0.001), in arterioles 176 +/- 7 vs 115 +/- 4 sq mu (P less than 0.001) and in preglomerular afferent arterioles (at 5 months) 131 +/- 8 vs 95 +/- 7 sq mu (P less than 0.001). The dilatation of small intrarenal arteries and arterioles in diabetic mice may result from progressive impairment of vasoconstriction and may be a cause of the glomerular hyperfiltration in diabetes.

Animals↗
PubMed1986

Urinary tract morphometry. An overview.

An overview is presented of the application of morphometry to conditions in the urinary tract, with the work of a number of researchers briefly summarized. The data discussed show that morphometric techniques are already being successfully applied in the differential diagnosis and grading of some diseases of the prostate, urinary bladder and kidney. In the prostate, nonneoplastic changes can be differentiated from neoplasms and prostatic carcinomas can be more precisely graded. Both cytologic and histologic preparations of bladder carcinomas can be graded by morphometric techniques. Morphometry has found another application in assisting in the distinction between normal kidneys and those with "minimal-change" disease. The specific criteria pertaining to the use of morphometric methods in each of these situations are also discussed.

Humans↗
PubMed1978

[Comparative histometrical studies in minimal proliferative intercapillary glomerulonephritis with (minimal changes) and without nephrotic syndrome (author's transl)].

Minimal changes in the glomerular structure and definitively provable only by the aid of morphometric methods. This is of value especially for the minimal proliferative intercapillary glomerulonephritis with and without nephrotic syndrome where, because of the different clinical symptomatology, changes in the morphology may be expected too which however, usually are not recognizable with the methods of light-microscopy. That is why morphometric analyses of kidney tissues of ever ten patients of both groups of the disease were made and the results compared with each after and against normal kidneys. It could be shown that the minimal proliferative intercapillary glomerulonephritis with nephrotic syndrome (minimal changes, lipoid-nephrosis) is accompanied by an increase of local cells, especially the mesangial cells, just as the same disease without nephrotic syndrome. Besides that there exists a clear increase of the mesangiummatrix in the minimal proliferative intercapillary glomerulonephritis without nephrotic syndrome. Because of the morphometric findings it is justified to make a demarcation of both groups of the disease as well as against the mesangioproliferative glomerulonephritis.

Adult↗
PubMed1977

[Immunohistological findings in non-glomerulonephritic renal disease (author's transl)].

Immunohistological study of 123 kidney biopsies of non-glomerulonephritic kidney diseases showed that deposits of immunoglobulins are found more often in cases of malignant than in cases of benign nephrosclerosis. Primary malignant nephrosclerosis is mostly associated with glomerular deposits of immunoglobulins. Positive immunohistological findings are frequent in cases of diabetic glomerulosclerosis, mainly within glomeruli, but also in tubular basement membranes and Bowman's capsule. In cases of glomerular amyloidosis we see cloudy-bandlike deposits, but are unable to differentiate cases with or without the nephrotic syndrome. If we consider an immunopathogenetic mechanism for the diseases discussed in terms of the present findings, it seems possible for primary malignant nephrosclerosis as well as for certain glomerular changes associated with acute renal failure or rejection of transplants. In diabetic glomerulosclerosis (apart from special forms with perimembranous lesions) and glomerular amyloidosis, we consider such a mechanism to be unlikely. By separating the non-glomerulonephritic diseases into different types of deposits we found pictures that correspond with immunocomplex diseases. Pictures resembling anti-basement membrane diseases have not been seen. Characteristic patterns of deposits were not found, thus immunohistology is without additional diagnostic value in the field of non-glomerulonephritis disease.

Acute Kidney Injury↗
PubMed1977

Quantitative morphological analysis of glomerular changes of the rabbit kidney on treatment with insulin preparations of different purity.

Thirty rabbits were immunized with MC insulin and high-molecular impurities of commercial insulin preparations (a+b component) over 30, 60 and 90 days. The serum insulin antibody titer was determined in animals as the insulin binding capacity. Further, a quantitative morphological analysis of the various types of glomerular cells and of the mesangium was performed on the glomeruli as a blind study. Significant mesangial cell proliferation and an increase in mesangial matrix were found on treatment with the a+b component whereas the animals treated with MC insulin exhibited only a transient and slight mesangial activation after 30 days. There was a positive correlation between the magnitude of the insulin binding capacity and the mesangial activation. Hence, the glomerular changes which are observed after treatment with insulin which is not highly purified must be attributed to the high treatment with insulin which is not highly purified must be attributed to the high molecular weight contaminants. Heterologous pure insulin must be regarded as having virtually no immunological effect.

Animals↗