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Biomedical subjects

C Leithner

Publications and source records attributed to C Leithner.

66 records · Page 4Linked to original sources
PubMed1976

[Bilirubin metabolism (author's transl)].

The degradation of haemoglobin haeme of senescent red blood cells - involving NADPH-dependent haeme oxygenase and biliverdin reductase - in the reticuloendothelial cells of the spleen, bone marrow and liver accounts for 80 to 90% of the 250 to 300 mg of bilirubin formed in 24 hours. The remaining 10 to 20% derive from catabolism of other haemoproteins and from the destruction of maturing red blood cells in the marrow. In studies with isotopically-labelled metabolic precursors of haeme this fraction can be found in the early-labelled peak. In plasma virtually all the bilirubin is tightly bound to plasma proteins, largely albumin, because it is only sparingly soluble in aqueous solutions at physiological pH. In the sinusoids unconjugated bilirubin dissocates from albumin, enters the liver cells across the cell membrane through non-ionic diffusion and is bound by the two cytoplasmic proteins Y (or ligandin) and Z. Little is known about the transfer of unconjugated bilirubin from these binding proteins to the smooth endoplasmatic reticulum, where it is converted to a water-soluble ester glucuronide by bilirubin UDP-glucuronyl transferase. The physiological significance of non-glucoronide conjugates (sulphate, disaccharides) is only of minor importance. Following conjugation, bilirubin is transferred rapidly across the canalicular membrane into the bile canaliculi. This process is energy-dependent and occurs against a concentration gradient. The epithelial lining of the intestine and of the gall bladder, which can easily reabsorb lipid-soluble unconjugated bilirubin, is virtually impermeable to organic anions of the size and charge of conjugated bilirubin, thereby ensuring efficient excretion of this pigment. In the intestinal tract bilirubin is reduced to urobilinogen, which is subsequently reabsorbed to some extent into the enterohepatic circulation, removed from plasma by the liver and excreted unchanged in the bile. This rapid bacterial reduction of bilirubin makes it unlikely that unconjugated bilirubin is formed and absorbed to an appreciable degree. The residual part of urobilinogen is further reduced to urobilin, stercobilin and dipyrrolmethenes and excreted in the faeces.

Bilirubin↗
PubMed1976

A morphologically different type of smooth muscle cell in the inner media of the splenic artery.

A morphologically different cell type to the typically smooth muscle cell has been found in the inner medial layers of the splenic artery. Besides the morphological differences, typical criteria for a smooth muscle cell are demonstrated, giving an account of their identity. Morphological details are described. The importance of these cells as regards lesions of the vessel wall is briefly discussed.

Adolescent↗
PubMed1976

Alterations of the internal elastic membrane in the coeliac trunk and its branches.

Changes in the internal elastic membrane of the coeliac trunk and its branches begin in the foetus. Usually these changes increase with advancing age. The intensity of involvement varies in different arteries, localized swelling is of particular importance as a measure of atherosclerotic involvement. There is a close relationship between morphology and chemical structure.

Adolescent↗
PubMed1976

Corticosteroids and proliferation of smooth muscle cells in arteries of renal transplants.

In the arteries of 17 rejected renal grafts 'activated' smooth muscle cells (ASMC) were discerned from a 'resting' type. Proliferation and fibre production by ASMC resulted in a marked thickening of intima. Each of four normal Wistar rats received 20 mg prednisolone i.v./day for one week and the development of hypertension was therapeutically prevented. Changes similar to those in the graft arteries were found in the rat aortas. We assume that SMC were stimulated by several mechanisms in rejection but also by extremely high dosed corticoids.

Adrenal Cortex Hormones↗
PubMed1976

[The use of an artificial kidney in edema therapy].

An artificial kidney (HFAK 5) was evaluated as an ultrafiltration device and was found to efficiently remove water from fluid-overloaded patients. The fluid removal rate was quantitated on a chronically hemodialyzed patient and an example of clinical application on a patient without renal insufficiency, is reported. It is suggested that ultrafiltration is a helpful method for treating refractory edematous states.

Adult↗
PubMed1975

Quantitative morphological investigations on smooth muscle cells in vascular surgical specimens and their clinical importance.

A distinct distribution of activated SMC could be demonstrated in atherosclerotic plaques and the neighbouring media of human beings. An increased proliferation was found in the younger age group and generally in the marginal regions of the plaques. The occurrence of activated SMC is thought to be a sequel of metabolic hypoxic damages. A high frequency of activated SMC is a bad prognostic sign in surgical specimens indicating a tendency for proliferation and occlusion.

Adult↗
PubMed1975

[Immunglobulin levels after kidney transplantation and during rejection crisis (author's transl)].

In the first three weeks after kidney transplantation the patients were examined for daily changes in immunoglobulin levels. Only very seldom was a decrease of IgM detected in our patients who had undergone splenectomy. During half of the rejection crisis there were indeed short periods of increase (spikes) in immunoglobulins. These were observed always before or concomitantly with the clinical diagnosis of a rejection reaction. In order to determine the connection between immunoglobulin-spikes and an approaching rejection episode the general one-sided binominal test was used. A significant relation was established between IgM peaks and an approaching rejection crisis. No such relation could be found for the IgA peaks observed. The IgG globulins showed no consistent pattern during a transplantation rejection. A persistent fall of the IgG globulins was noted in the first ten days after renal allograft with the immunosuppressive regimen of an initial gramme of methylprednisolon and high dosage of azothioprine. A good correlation was observed with the simultaneous depression of serum albumin concentrations. As losses of protein in urine are minimal (already confirmed by other authors), it must be assumed that in the first place a high rate of catabolism and a restriction in the protein synthesis is responsible for the decrease in the IgG globulins and the serum albumins.

Azathioprine↗
PubMed1975

A simple test for early detection of severe renal homograft rejection.

Adding urine to a standard buffered fibrinogen solution and then coagulating it with thrombin gives reproducible coagulation times with normal urines. Coagulation of fibrinogen by thrombin is prolonged in acid solutions with a pH below six. Urines of high acidity lower the buffer pH of the fibrinogen solution below a value of six thus rendering the system uncoagulable or significantly prolonging the coagulation time. With this test system we found that out of 16 severe homograft rejections 15 were accompanied by a high acid excretion in six-hour urine specimens. Ten of these acid episodes became apparent 12 to 48 hr before clinical symptoms and before elevation of the serum creatinine could be detected.

Creatinine↗