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Biomedical subjects

E Ritz

Publications and source records attributed to E Ritz.

At least 883 records · Page 49Linked to original sources

Improved sexual function in male haemodialysis patients on bromocriptine.

The effect of bromocriptine on sexual activity was studied in male haemodialysis patients in a single-blind placebo controlled trial with random cross-over. At a dose of 2.5 mg bromocriptine twice day, plasma-prolactin concentrations were consistently reduced, while sexual function as assessed by a questionnaire was markedly improved. At the doses used, side-effects, particularly hypotension, were common, but bromocriptine helped to restore sexual function in dialysed patients.

Bromocriptine↗

Analysis of clinical laboratory data by biplot methods using a three-dimensional display: discrimination of renal stone-patients with idiopathic hypercalciuria and primary hyperparathyroidism.

The biplot technique is a very useful graphical method to display the relationships between row and column characteristics in two-way tables. This method is applicable as long as the rank-2 approximation explains a large part (e.g. 95%) of the whole variability. However, since in large tables only a rank-3 approximation will yield such a high degree of explanation, a three-dimensional biplot technique has been introduced, using a 3d-screen as a matter of presentation of clinical laboratory data. The value of such a procedure is illustrated using as a clinical example a patient population with recurrent renal stone formation due either to primary hyperparathyroidism or to idiopathic hypercalciuria.

Adult↗

Urinary matrix calculi consisting of microfibrillar protein in patients on maintenance hemodialysis.

In seven patients on maintenance hemodialysis, de novo recurrent renal stone formation was observed. In all patients, the underlying disease was glomerulonephritis, with or without the nephrotic syndrome. All patients had considerable persistent proteinuria. The stones consisted predominantly of protein, as revealed by amino acid analysis, and had a negligible carbohydrate and lipid content. Only in some specimens, X-ray diffraction and scanning electron microscopy revealed the presence of small amounts of whewellit (calcium oxalate monohydrate) and/or uric acid. In semithin sections, the stones had a laminated texture and exhibited structural anisotropy under polarized light. With transmission electron microscopy, they were found to consist of peculair microfibrils. The proteinaceous material differed from fibrin or Tamm-Horsfall-protein, as indicated by ultrastructure, carbohydrate analysis, and amino acid analysis. Symptomatic de novo matrix stone formation constitutes another complication of dialyzed patients which has not been reported so far.

Adult↗

Isolation and renal localisation of urokinase.

Physico-chemical characteristics of urokinase in urine were studied by immunological and chemical methods. By agar zone electrophoresis, commercial urokinase preparations could be separated into an anodic and cathodic fraction. The latter reacted with urokinase antibodies with two precipitation bands. Band I displayed the major part of urokinase activity and migrated as a beta-globulin with a molecular weight of 32,000 daltons. Band II showed immunological identity with human serum, human albumin, alpha-2-macroglobulin and alpha-2-HS-glycoprotein. The specific activity of the cathodic fractions was up to 80,000 ploug units/mg protein. The ratio esterase/fibrinolytic activity did not change during the purification procedure. Further purification of the fractions with higher specific activity by affinity chromatography was unable to eliminate material cross reacting with human antisera (Band II). These findings permit the conclusion, that urokinase activity in urine is not confined to a homogeneous protein fraction. Activity is found both in a low molecular weight fraction and in a high molecular weight complex which contains serum proteins. These cannot be removed by exhaustive purification procedures and may play an important role in stabilizing and/or protecting urinary urokinase against proteolytic degradation. With Todd's technique diffuse fibrinolytic activity could be demonstrated in the kidney in the iuxtamedullary border region, (venae arcuatae, venae interlobulares, vasa recta) and in the epithelium of the calyces. Urokinase activity was specifically blocked by highly purified urokinase antibodies and could thus be distinguished from nonspecific proteolytic activity. The topographic relationship to medulla and uroepithelium may point to a role of urokinase in maintaining patency in slow flow systems.

Endopeptidases↗

[Lactic acidosis--a possible complication in buformin-treated diabetics (author's transl)].

Lactic acidosis is defined as a state of metabolic acidosis (arterial pH below 7.36) due to an increase in the blood concentration of lactate above 2 mEq/l. Lactic acidosis may occur under a variety of conditions; the biguanide-induced lactic acidosis is due to the toxic effects of biguanides (buformin, metformin, phenformin). The clinical picture is characterized by the occurrence of disturbances of consciousness, severe acidosis with Kussmaul's respiration, shock, hypothermia and in about 30% of all cases hypoglycemia. Apart from the general principles of intensive medical care, therapy should comprise correction of the acid-base-disturbances and elimination of the offending biguanide. The efficacy of hemodialysis in the treatment of biguanide-induced lactic acidosis is difficult to evaluate. By a more sensible use of biguanides, lactic acidosis secondary to drug administration should become a rare event.

Acidosis↗