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Biomedical subjects

H Sinzinger

Publications and source records attributed to H Sinzinger.

At least 523 records · Page 29Linked to original sources
PubMed1982

[Prostacyclin synthesis-stimulating plasma factor in different age groups].

The vascular synthesis of prostacyclin (PGI2), the most powerful endogenous inhibitor of platelet aggregation and vasodilator, plays a central role in prevention of vascular damages by uncontrolled platelet aggregation. PGI2 seems to be an important defense mechanism of vascular system against, among others, the development of atherosclerosis. The PGI2-production of blood vessels is stimulated and thereby decisively influenced by a plasma factor (PF). This PF participates in the pathogenesis of several diseases. This activity of PF is for instance increased in renal insufficiency, which explains partly the haemorrhagic diathesis occurring in this illness. On the other hand there seems to be a hereditary lack of PF in patients suffering from thrombotic-thrombocytopenic purpura or haemolytic-uraemic syndrome. The PF was estimated in 62 healthy subjects collected in 8 age groups by means of bioassays and RIA-determination of 6-oxo-PGF1 alpha, the stable PGI2-metabolite, in tissue cultures. No differences of PF in the different age groups could be demonstrated. These findings support the view, that the PF as an important regulator of vascular PGI2-synthesis is functioning absolutely normal in older age.

Adolescent↗
PubMed1982

[Molsidomine, a coronary drug with platelet-aggregating inhibitory activity].

The influence of molsidomin (4 mg i.v.) on platelet function, on the plasma concentrations of 6-oxo-PGF1 alpha, the stable metabolite of prostaglandin I2, and thromboxane B2, the stable metabolite of thromboxine A2 was determined in ten patients with coronary heart disease. Prostaglandin I2 is generated in the vessel wall and is a potent vasodilator and inhibitor of platelet aggregation, whereas thromboxane A2 is a vasoconstrictor and a proaggregatory substance. In addition, in-vitro tests were performed, too. 60 min after bolus injection a decrease of systolic and diastolic blood pressure was observed, whereas heart rate remained nearly constant. Platelet aggregation decreased significantly; the addition of PGI2 in vitro had an additive effect. The plasma concentrations of 6-oxo-PGF1 alpha increased after 60 minutes, whereas thromboxane B2 concentrations remained unchanged. In vitro, SIN1, a metabolite of molsidomin generated in the liver, led to a dose-dependent inhibition of ADP-induced platelet aggregation, whereas molsidomin was nearly inactive. Thus molsidomin shows an inhibition of platelet function besides the known antianginal properties. The vasodilatatory and platelet inhibiting effects of this compound may be due partly to a stimulation of the prostaglandin I2 synthesis in the vessel wall.

Angina Pectoris↗
PubMed1982

Increased deposition of 111Indium labelled platelets in chronically rejected kidney transplants.

Increased deposition of 111In-oxine labelled autologous platelets in chronically rejected kidney transplants was demonstrated using a gamma-camera and by measurement of a platelet uptake index (PUI). In this group of patients the PUI correlated indirectly with the platelet half-life and was statistically different from the PUI found in stable transplant patients who acted as controls. It is therefore suggested that platelets may play a key role in chronic rejection by the release of a mitogenic factor which promotes the development of obliterative arterial lesions in the transplant.

Adult↗
PubMed1982

[The use of labeled thrombocytes in the monitoring of patients after kidney transplantation].

Indium 111 (111In) labelled autologous platelets were used in the diagnostic observation of patients after renal transplantation. 75 patients were collected in 3 groups of 25 cases each. The first group consisted of patients who were examined during the first 4 weeks after transplantation. Group 2 were patients suffering from histologically proved chronic graft rejection. The 3rd group included cases with good and stable transplant function tested at least 9 months after transplantation. By means of a computerized static study the transplants were examined under the gamma-camera concerning a platelet trapping. Thereby a platelet-uptake-index (PUI) was calculated and compared with the platelet half-life-time (t1/2). This diagnostic method turned out to be suitable for early diagnosis of acute graft rejection. Hereby the PUI increased from 1.13 +/- 0.11 to 1.74 +/- 0.17. The further course of rejection episode manifested itself in corresponding changes of PUI. In irreversible rejections the PUI stayed in the high range or increased further. On the other hand reversible graft rejections showed a reduction of PUI, however, in the most cases not to the original basic level. The platelet t1/2 exhibited a strong negative correlation with PUI. Cases suffering from chronic transplant rejection revealed significantly higher platelet trapping by the graft than patients with good and stable transplant function.

Adolescent↗
PubMed1982

[Quantitative-histomorphological study of the abdominal aorta in children and adolescents].

127 abdominal aortas of children and adolescents aged 0-20 years were examined histomorphologically. The quantitative analysis gave the following results: (1) The intimal thickness increases continuously with age. The maximal intimal growth can be observed between the 1st and 3rd and the 12th and 19th year of age, respectively. (2) The media exhibits a similar increase in thickness with a maximal growth between the 1st and 3rd and in the 12th year. (3) The intima-media index rises rapidly from birth until the 3rd year, with a plateau thereafter, and then increases again between the 14th and 18th year. (4) The mean values for these measurements were higher in males than in females in all the age groups except for the 1st year.

Adolescent↗
PubMed1982

[Value of the detection of arteriosclerotic lesions with labeled autologous thrombocytes].

In 44 patients with clinical signs of carotid artery stenosis a positive Doppler-ultrasound was obtained. In all patients the lesions were confirmed by angiography. In the patients labelling of autologous platelets with 111Indium-oxine-sulphate was done in order to calculate the platelet half-life. In addition we tried to visualize the verified atherosclerotic lesions under a gamma-camera. In all patients the platelet half-life was significantly shortened in comparison to the controls. In none of the patients studied a visualization of the angiographically verified atherosclerotic lesions could be obtained. These findings point out, that only in recently developed and very severe atherosclerotic lesions the number of platelets deposed on the vascular surface is enough to allow gamma-camera imaging.

Aged↗
PubMed1981

[Prostacyclin formation in human cancer tissue of the gastrointestinal tract (author's transl)].

Prostacyclin synthesis was studied by means of bioassay in histologically classified biopsy material derived from the human gastrointestinal tract. Tumour tissue generated significantly more prostacyclin than normal tissue. Whether this enhanced PGI2 formation is due to an increased number of endothelial cells in tumour tissue, or represents a characteristic property of the tumour cell itself is not yet clear. This property could be used in future for the detection and control follow-up of malignant disease by means of radioimmunological determination of stabile metabolites as a tumour marker.

Adult↗
PubMed1981

[Influence of the venous wall--platelet interaction by dihydroergotamine (author's transl)].

The incubation of rabbit venous rings (vena cava) is followed by the synthesis and release of prostacyclin (prostaglandin I2, PGI2), as measured by the inhibition of ADP-induced platelet aggregation. The incubation of the venous rings in dihydroergotamine leads to a stimulation of PGI2 synthesis and/or release. This effect of dihydroergotamine, apart from the vasoactive properties of this compound, might prove advantageous as a prophylactic measure in venous thrombosis.

Adenosine Diphosphate↗
PubMed1981

[Platelet sensitivity to prostacyclin (PGI2) in patients with juvenile-onset diabetes mellitus (author's transl)].

Platelet function (ADP-induced platelet aggregation) in 20 patients with juvenile-onset diabetes mellitus was not different from that of age- and sex-matched controls. Platelet sensitivity to exogenous PGI2 was not diminished in diabetic patients. No sex differences were detected. There was no correlation between concomitant blood glucose levels and platelet sensitivity to PGI2.

Adenosine Diphosphate↗
PubMed1981

Decreased sensitivity of human platelets to PGI2 during long-term intraarterial prostacyclin infusion in patients with peripheral vascular disease--a rebound phenomenon?

During successful treatment of peripheral vascular disease with synthetic prostacyclin no alteration in platelet function was reported (1). In 8 patients infused with synthetic prostacyclin continuously for 7 days intraarterially, the platelet function was monitored. Special attention was drawn to the platelet sensitivity in vitro for PGI2, which is discussed as an important factor maintaining the hemostatic balance. In all the patients with peripheral vascular disease between 24 and 48 hours after the beginning of the infusion a sudden decrease in platelet sensitivity accompanied by an increase in platelet count could be seen. These dramatic alterations representing probably a rebound phenomenon occurring during long-term PGI2-treatment might be an explanation for a non-beneficial effect of the treatment and in some cases a limiting factor for the continuation of the infusion itself. It is not clear, if this rebound phenomenon is due to a stimulation of an endogenous inhibitor, lowering the synthesis of a naturally occurring substance acting against this inhibitor or tachyphylaxia.

Aged↗
PubMed1981

Sensitivity of platelets to prostaglandins in cornary heart disease and angina pectoris.

The platelet sensitivity to the antiaggregatory prostaglandins (PGI2, PGE1 and PGD2) was studied in patients with angiographically verified coronary heart disease. The sensitivity was tested in vitro by inhibiting the ADP-induced platelet aggregation by various concentrations of these prostaglandins. Beside the age dependent alterations of platelet sensitivity reported earlier, there is a statistically significant decrease in sensitivity for PGI2 and PGE1 in patients with coronary heart disease. In contrast, no significant change for the PGD2-sensitivity could be observed. In angina pectoris a further significant decrease in sensitivity (again only for PGE1 and PGI2) was found which returned back to the starting values within a few hours. In patients with maturity onset diabetes and coronary heart disease the sensitivity was always lower than in those patients with coronary heart disease alone. Changes in platelet sensitivity might play a key role in initiating and progressing atherosclerosis by an immediate disturbance of hemostatic balance. The studies further support the hypothesis that PGI2 and PGE1 share the same receptor on the platelet surface.

Adult↗
PubMed1981

Treatment of chronic kidney transplant rejection with prostacyclin - reduction of platelet deposition in the transplant; prolongation of platelet survival and improvement of transplant function.

8 patients with chronic kidney transplant rejection were treated intravenously with prostacyclin during 5 days. This treatment seemed to have a beneficial effect as measured by platelet deposition in the transplant and prolongation of platelet survival. In the majority of cases the transplant function improved. A longer duration of this therapeutic effect could be a new way for the long-term treatment of chronic kidney transplant rejection.

Adult↗
PubMed1981

Effects of prostacyclin on ultrastructural features of human platelets in vitro.

Examining platelets plasma-membrane by freeze-etching (FE)-technique irregularly place among the "particles", some larger formations, called by us "protuberances" can be seen. These protuberances may represent the stomata of the open canalicular system (OCS) and the morphological aspect of an exocytotic process. Addition of prostacyclin to platelet rich plasma (PRP) leads to a decrease of the average value of protuberances which is statistically significant in comparison to control platelets.

Blood Platelets↗
PubMed1981

Increased plasma levels of 6-oxo-prostaglandin F1 alpha, a stable metabolite of prostacyclin, in acute kidney transplant rejection.

In 30 patients after kidney transplantation, 6-oxo-PGF1 alpha was examined in unextracted plasma by a specific radioimmunoassay. The material was divided into three groups. Patients with acute transplant rejection showing the highest 6-oxo-PGF1 alpha levels, patients with delayed transplant rejection having significantly lower plasma values and a third group of patients with stable transplant function. In these patients the plasma 6-oxo-PGF1 alpha-values were below the lower limit of detection (70 pg/ml). The enhanced 6-oxo-PGF1 alpha during rejection crisis could be interpreted as a self protection mechanism of vascular tissue which is, however, not sufficient in many cases, to prevent the irreversible rejection of the transplant.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Value of platelet sensitivity to antiaggregatory prostaglandins (PGI2, PGE1, PGD2) in 50 patients with myocardial infarction at young age.

Based upon earlier findings of our group that not only the synthesis of antiaggregatory prostaglandins by the vessel wall is altered in atherosclerotic vascular tissue of patients, but also the sensitivity of their platelets to these prostaglandins is changed, we examined a well defined group of 50 patients with myocardial infarction before the age of 40 years. In all patients the coronary heart disease was verified by angiography. The sensitivity of the platelets was examined in relation ot the smoking habit, the type and presence of hyperlipoproteinemia, one, two and three vessel disease and familial history. Except for hyperlipoproteinemia and smoking, all the patients were free of any additional risk factor. It is demonstrated that the platelet sensitivity to the antiaggregatory prostaglandins is significantly diminished in hyperlipoproteinemics in comparison to a control group.

Adult↗