PubMed Health⌕ Search

Biomedical subjects

F Sandhofer

Publications and source records attributed to F Sandhofer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Studies on the role of specific cell surface receptors in the removal of lipoprotein (a) in man.

The binding of 125I-lipoprotein (a) [Lp(a)] to cell surface receptors was studied on cultured human fibroblasts. The results were compared with corresponding data obtained with 125I-low density lipoproteins (LDL). Equilibrium binding studies showed that Lp(a) is bound with high affinity by the cell surface receptors. The maximum binding capacity for Lp(a) was 37% lower than for LDL. For Lp(a) and LDL, the Scatchard plots displayed linearity, indicating a single category of binding sites. Half-maximal saturation occurred at a concentration of 9.52 +/- 1.04 nM for Lp(a) and 7.76 +/- 1.29 nM for LDL. Competition binding experiments revealed that Lp(a) and LDL are nearly equally potent in competing each other for the binding sites. Binding of Lp(a) and LDL were followed by suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. Cyclohexanedione treatment of Lp(a) and LDL completely abolished receptor binding. Neither Lp(a) nor LDL were specifically bound by fibroblasts obtained from a patient with homozygous familial hypercholesterolemia (FH). The removal mechanisms for Lp(a) and LDL were further compared by in vivo studies. Radioiodinated Lp(a) and LDL were injected intravenously into 12 normolipemic individuals to measure kinetic parameters of these two lipoproteins simultaneously in each subject. Mean fractional catabolic rate (FCR) of Lp(a) was 0.260 +/- 0.060 and mean FCR of LDL was 0.377 +/- 0.077 (mean +/- SD). In each subject, FCR of Lp(a) was lower than the FCR of LDL; the mean difference was 31%. The absolute synthetic rate of Lp(a) was significantly lower than the corresponding value of LDL. In each individual, the percentage of total Lp(a) that was contained in the intravascular space was higher than the corresponding value of LDL; the mean difference was 19%. A highly significant positive correlation was found between FCR of LDL and FCR of Lp(a) (r = 0.853, P less than 0.01). No relationship was found between the serum concentration of LDL-apolipoprotein B and Lp(a). The serum level of Lp(a) was positively related to the absolute rate of Lp(a) synthesis (r = 0.979, P less than 0.01). The serum level of LDL-apolipoprotein B was inversely related to FCR of LDL (r = 0.613, P less than 0.05). In a patient with homozygous FH, FCR of LDL was 0.205 and FCR of Lp(a) was 0.210. The results of these studies show that Lp(a) is specifically bound with high affinity to the same receptors of human fibroblasts as LDL. The affinity and maximum binding capacity are slightly lower for Lp(a) than for LDL. The results of the turnover studies are consistent with the assumption that Lp(a) is removed from the plasma by similar mechanisms as LDL.

Adolescent↗
PubMed1983

[Wegener's granulomatosis as a rare cause for kidney failure].

Course and treatment of a case of Wegener's granulomatosis are reported. A 39-year-old man admitted to the hospital because of abnormal densities demonstrated by the X-ray examination of the chest. The patient developed a rapidly progressive renal failure with renal insufficiency. Diagnosis was obtained by biopsys from the upper respiratory tract and from the kidney. During hemodialysis and immunosuppressive therapy renal function improved and hemodialysis could be stopped. The patient was discharged from the hospital and kept on immunosuppressive therapy. The patient omitted the medication by himself and renal insufficiency reappeared. The disease was progressive and the patient died because of intestinal bleeding. Apart from the description of the symptoms of this rare disease, problems of diagnosis and treatment are discussed.

Acute Kidney Injury↗
PubMed1982

[Treatment of ulcers with pirenzepin. Results from clinic and practice].

In two studies the beneficial effect of Pirenzepine in the treatment of peptic duodenal and gastric ulcers was investigated in 1686 outpatients. Study 1 includes patients treated and controlled mainly in hospitals, in study 2 treatment and control was performed mainly by practitioners. After four weeks of treatment healing of duodenal ulcers was observed in 68% of the patients in study 1 and 66% in study 2. Healing of peptic gastric ulcers was observed in 62% of the patients in study 1 and 53% of the patients in study 2. Mild anticholinergic side effects were observed in approximately 10% of the patients. Healing rates under Pirenzepine are similar those reported for Cimetidin or Carbenoxolon. It is concluded that Pirenzepine has a beneficial effect in the treatment of peptic duodenal and gastric ulcer disease.

Adult↗
PubMed1980

Symptomatology of the most severe form of tuberculous meningitis.

Seven cases of the most severe form of tuberculous meningitis, in which a midbrain syndrome developed, are reported. Three different types of progress were observed. Exudative inflammation and cerebral edema dominated in the first group, causing the rapid development of the acute midbrain syndrome, which may turn into a bulbar syndrome. In the second group the development of the midbrain was delayed and an apallic syndrome followed. The morphological examination disclosed local diencephalic and midbrain lesions caused by herniation and specific vasculitis and vascular compression. The third group showed disintegration of cortical function as a result of parenchymal lesions, apart from local midbrain symptoms which never fully intensified into the midbrain syndrome. Observation of the progress of the disease proved that late diagnosis and delayed therapy were decisive in cases of the most severe form of tuberculous meningitis.

Adolescent↗
PubMed1980

Turnover of lipoprotein (a) in man.

An elevated concentration of lipoprotein (a) [Lp(a)] in the serum has been considered a risk factor for coronary heart disease by various investigators. In the present study, the turnover of Lp(a) was investigated in nine individuals with serum Lp(a) levels ranging from 1 to 68 mg/100 ml. After intravenous injection of radioiodinated Lp(a), the radioactivity time-curve of the serum and the specific activitity time-curves of the isolated Lp(a) and Lp(a) apolipoproteins were measured for 14 d. More than 97% of the label was found in the protein moiety of Lp(a). During the entire study period, the serum radioactivity remained with Lp(a), only insignificant amounts of radioactivity were detectable in other lipoprotein fractions. The serum radioactivity time-curves and the specific activity time-curves of the isolated Lp(a) and Lp(a) apolipoproteins were identical. The kinetic parameters of Lp(a) turnover were calculated in terms of a two-compartment model. 76.5+/-5.1% (mean+/-1 SD) of total Lp(a) was contained in the intravascular space. The biological half-life of Lp(a) was 3.32+/-0.52 d, the fractional catabolic rate (FCR) was 0.306+/-0.054/d, and the rate of synthesis was 5.00+/-3.37 mg/kg/d. A positive correlation was found between serum concentration and synthetic rate of Lp(a) apoprotein. No relationship could be demonstrated between serum level and FCR of Lp(a). The results of this study indicate that Lp(a) is not converted to other serum lipoproteins. From the correlations between serum concentration and kinetic parameters of Lp(a) it is concluded that an elevated Lp(a) level is the consequence of an increased Lp(a) apoprotein synthesis.

Adult↗
PubMed1979

Lipoprotein (a) is not a metabolic product of other lipoproteins containing apolipoprotein B.

125I-Labeled autologous very low density lipoprotein (VLDL) was injected intravenously into three lipoprotein (a) positive individuals. One other lipoprotein (a) positive subject received 125I-labeled VLDL from a a lipoprotein (a) negative donor. Specific activity of apolipoprotein B in VLDL, low density lipoprotein (LDL) and lipoprotein (a) was measured for 5 days. In the lipoprotein (a) fraction only traces of radioactivity could be detected, which were caused by contamination with labeled LDL. No precursor-product relationship existed between apolipoprotein B in VLDL or LDL and apolipoprotein B in lipoprotein (a). One lipoprotein (a)-positive individual was kept on a fat-free diet for 4 days to prevent chylomicron formation; no change in the serum level of lipoprotein (a) could be detected under these conditions. The data of this study indicate that lipoprotein (a) is not a metabolic product of VLDL or LDL. Also chylomicrons are not likely to play role as a precursor for lipoprotein (a). It is concluded that lipoprotein (a) is synthesized as a separate lipoprotein.

Adult↗
PubMed1978

Studies on the metabolism of the lipoprotein Lp (a) in man.

Lp(a) was isolated and labeled by reductive alkylation. Radioactivity only entered the protein moiety of the lipoprotein. No change in the immunological or physicochemical properties of Lp(a) was noted after the radiomethylation. After incubation of labeled Lp(a) with whole serum for 24 h in vitro, more than 99% of the radioactivity of the incubated sample was found in Lp(a). In 4 subjects Lp(a) was injected intravenously. A linear decline of the specific activity of Lp(a) in the serum was found when it was plotted semilogarithmically against time. Half-lives of Lp(a) in the serum were 35, 38, 53 and 58 h. In one subject, the "soluble" and the "insoluble" apoproteins of Lp(a) showed the same half-life as the whole Lp(a) molecule. This suggests that no exchange of Lp(a) apoproteins with lipoproteins of other density classes took place. At different times after the injection of Lp(a), 3--8% of the radioactivity of the serum was found in Lp B, and less than 2% of the radioactivity was detectable in VLDL and the fraction having a density of greater than 1.110 g/ml.

Adult↗
PubMed1978

Hepatic and extrahepatic triglyceride lipase activity in uraemic patients on chronic haemodialysis.

In eleven patients with chronic renal insufficiency treated by intermittent haemodialysis and in ten normal subjects, hepatic and extrahepatic triglyceride lipase activity of post heparin plasma was selectively measured, utilizing the different sensitivity of both enzymes to inhibition by protamine sulphate. In uraemic patients, hepatic triglyceride lipase activity was significantly decreased and extrahepatic triglyceride lipase activity was normal when compared with the control group. The uraemic subjects showed a moderate hypetriglyceridaemia; their serum cholesterol level, however, was normal. The high triglyceride concentration was due to an increase of very low density lipoproteins and low density lipoproteins of the density between 1.006 and 1.019 g/ml (LDL1). The concentration of low density lipoproteins of the density between 1.019 and 1.063 g/ml (LDL2) was decreased. LDL2 were relatively rich in triglycerides when compared with LDL2 from the control group.

Adult↗
PubMed1974

Separation of the main lipoprotein density classes from human plasma by rate-zonal ultracentrifugation.

The major lipoprotein density classes (chylomicrons-VLDL, LDL, HDL(2) and HDL(3)) were isolated from human plasma in a two-step ultracentrifugal procedure using the Ti-14 zonal rotor. The isolation of the two major high density lipoprotein subclasses (HDL(2) and HDL(3)) was achieved in a 24-hr run using a nonlinear NaBr gradient in the density range of 1.00-1.40. The lipoproteins with a density < 1.063 found in the rotor's center were isolated in a second run of 140 min duration using a continuous linear NaBr gradient in the density range of 1.00-1.30. The isolated lipoproteins were analyzed for chemical composition and for electrophoretic mobility; purity of isolated fractions was checked by immunochemistry. The lipoproteins exhibited flotation rates, chemical compositions, and molecular weights similar to those found with the common sequential procedures in angle-head rotors. The amount of lipoprotein lipids in the bottom fraction of the zonal rotor was comparable to that of the angle-head rotor. The described method yields the main lipoprotein density classes free from albumin in a very short running time; compared with the rate-zonal techniques already in use, this method allows the quantitative separation of an additional lipoprotein density class (HDL(2)) without increasing the running time. Furthermore, this procedure proved to be suitable for isolation of plasma lipoproteins from subjects with various types and varying degrees of hyperlipoproteinemia.

Adolescent↗