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Biomedical subjects

K W Kühn

Publications and source records attributed to K W Kühn.

9 recordsLinked to original sources

Age-related glomerulosclerosis and interstitial fibrosis in Milan normotensive rats: a podocyte disease.

In Milan normotensive (MNS) rats glomerulosclerosis and interstitial fibrosis develop spontaneously in the absence of hypertension. Renal changes were sequentially assessed in these rats between 2 and 10 months of age. At 10 months, rats were characterized by heavy proteinuria, increased serum creatinine, focal or global glomerulosclerosis in 51 +/- 12% of the glomeruli as well as tubulointerstitial injury involving > 25% of the section area. Cell injury in podocytes (evidenced as increased expression of desmin and by electron microscopy) and interstitial fibroblasts (increased expression of alpha-smooth muscle actin) and mild glomerular hypertrophy were witnessed as early as three to four months of age and preceded glomerulosclerosis and interstitial fibrosis. Only minor evidence of mesangial cell activation (as assessed by glomerular (de novo alpha-smooth muscle actin or type I collagen expression or increased cell proliferation) was noted throughout the observation period. Later stages of the disease were characterized by glomerular and/or tubulointerstitial macrophage influx and osteopontin expression (a chemoattractant), mild accumulation of lymphocytes, platelets, fibrinogen, as well as by a progressive accumulation of various matrix proteins. Progressive renal disease in MNS rats is thus noteworthy for the relative lack of mesangial cell activation. Rather, early podocyte damage, induced by yet unknown mechanisms, may underlie the development of glomerulosclerosis and subsequent interstitial fibrosis.

Actins↗

Excessive hypernatremia in a patient with renal amyloid disease.

A 24-year-old Italian male presented with a nephrotic syndrome in September 1984. In February 1985 renal biopsy showed amyloid disease with tubular atrophy and interstitial fibrosis. Edema was treated with furosemide, and cholchicine was started. Because he feared side effects of drug therapy, the patient stopped all medication by July 1985. Instead, he decided to restrict severely fluids in order to fight edema. In early November 1985 his family noted he was becoming increasingly lethargic. Two weeks later, on his admission to the hospital, he had a serum sodium concentration of 193 mmol/l and serum osmolality of 397 mosm/kg. Apart from mild mental status changes neurological examination was normal. The fluid deficit was slowly corrected. He was discharged three weeks later with normal serum electrolytes. This case demonstrates that (1) severe hypernatremia can present with mild neurological symptoms and (2) it can be survived provided that it develops slowly and is corrected cautiously.

Adult↗

Performance and biocompatibility of the FD 100 Gambrane hollow-fiber dialyzer.

In order to obtain performance data and biocompatibility characteristics of the two new Gambrane FD 100 polycarbonate hollow-fiber dialyzers (y-sterilized, dry or prefilled with isotonic saline) a paired in vivo evaluation was carried out. The measured data indicate that residual blood volume and small molecular weight clearances of Gambrane hollow-fiber dialyzers are not significantly different from comparable Cuprophan dialyzers. Small molecular clearance values are not affected by the significantly different ultrafiltration coefficients of the two tested FD 100 dialyzers. Biocompatibility of Gambrane as reflected by white blood cell count, platelet count and C3d is superior to Cuprophan.

Biocompatible Materials↗

Is renal involvement a prognostic parameter in patients with infective endocarditis?

Renal involvement (RI)--defined as proteinuria greater than 150 mg per 24 h with haematuria or impaired glomerular filtration rate--was studied in 80 patients with infective endocarditis (IE). Proteinuria was measured quantitatively and further differentiated by the SDS-polyacrylamide-gel electrophoresis. RI was found in 40 patients (50%) with proteinuria from 150 to 8000 mg per 24 h. SDS-PAGE revealed a tubular protein pattern in 17 patients, a glomerular pattern in 6 and a glomerulo-tubular pattern in 17. Mortality rate was significantly higher in patients with RI (40%) than in those without (7.5%), and was not related to the type of infected valve, infective organisms, method of treatment (surgical or medical) or embolic events. Following successful treatment of IE, 18 out of 23 patients showed complete normalization of renal function. Renal involvement in patients with IE may be of prognostic significance--indicating an impaired prognosis.

Adolescent↗

Ultrastructural architecture of proteoglycans in the glomerular basement membrane. A cytochemical approach.

Rat kidneys were perfused with fixative solutions containing either a) a polycationic dye (Alcian blue 8 GX, Astra blue 6 GLL, cuprolinic blue, ruthenium red), b) a monocationic dye (safranine 0), or c) Alcian blue in the presence of a 0.3 M MgCl2 concentration. Whereas solutions of a revealed the glomerular basement membrane proteoglycans as particles or threads 60 nm apart and arranged in a reticular pattern, solutions of b and c demonstrated new morphological aspects of these molecules. They appeared as tiny filamentous structures, about 100 to 160 nm long, ordered in a network-like pattern with a mesh of about 60-nm width. The filaments displayed lateral branches about 20 nm apart and about 25 nm long, projecting within the meshes. We suggest that the filamentous structures are the protein core, and the branches are the glycosaminoglycans of proteoglycan molecules. Because of this arrangement the negatively charged sites of the glomerular basement membrane would lie closer to each other than previously assumed.

Animals↗

Cell junctions of the glomerular epithelium in a very early vertebrate (Myxine glutinosa).

The glomerular epithelial cells of the Atlantic hagfish (Myxine glutinosa) lack a slit diaphragm which is replaced by filaments. The epithelial cells show numerous occluding junctions (maculae and fasciae occludentes), septate desmosome-like junctions and desmosomes. The present findings are compared with available data on developing and mature glomerular epithelial cells of mammals.

Animals↗

Morphological and functional aspects of the glomerular basement membrane.

Addition of Alcian Blue to the fixative reveals structural elements bearing negatively charged sites within the glomerular capillary wall of the rat kidney. According to previous research (review by Brenner et al., 1977), these charges represent one of the most important functional components of the glomerular filtration barrier. Alcian Blue also demonstrates negatively charged microfibrils (probably glycoproteins) of the mesangial matrix. Preliminary observations of glomeruli of lower vertebrates suggest that there is always a close correlation between the presence of microfibrils and mesangial cells.

Alcian Blue↗

Phenacetin abuse and chronic pyelonephritis.

A history of phenacetin abuse has been found almost three times more frequently among subjects diagnosed on clinical and functional grounds as suffering from chronic pyelonephritis than among those suffering from other renal diseases or among non-renal controls. The chronic pyelonephritis in subjects admitting phenacetin abuse has been usually characterized by a more frequent intense bacteriuria and leucocyturia, by a slightly more frequent haematuria, history of renal colic, presence of stones and more rapid downhill course of glomerular filtration rate than in subjects without phenacetin abuse. A sterile lesion also without any past evidence of infection was observed only in subjects with the heaviest analgesic abuse. The discontinuation of the abuse in 5 subjects led to an improvement of the renal function.

Chronic Disease↗