PubMed Health⌕ Search

Biomedical subjects

G Siegert

Publications and source records attributed to G Siegert.

30 records · Page 2Linked to original sources
PubMed1997

Anomalies of lipoprotein pattern and fibrinolysis in acromegalic patients: relation to growth hormone levels and insulin-like growth factor I.

The influence of hGH and IGF-I levels on lipid-, lipoprotein metabolism and fibrinolysis were studied in 23 patients with active acromegaly (14 women and 9 men, mean age 49.8 +/- 2.1 years) compared to a sex, BMI and age-matched control group. Mean Lp(a) levels were significantly higher in acromegalics than in controls (469.8 +/- 140.1; n = 23 vs. 162.7 +/- 64.9 mg/l; n = 111; p < 0.01). We found elevated apolipoprotein A-I and Apo E-concentrations in acromegalic patients compared to controls (apo A-I: 1.79 +/- 0.06 vs. 1.46 +/- 0.04 g/l; p < 0.01; apo E: 98.35 +/- 6.4 vs. 72.53 +/- 3.38 mg/l; p < 0.05). 30% of the acromegalics showed increased plasminogen activator inhibitor activity (PAI) while 66% had increased tissue-type plasminogen activator (t-PA) concentrations. There was a correlation between hGH and Lp(a) (r = 0.414; p = 0.05), between hGH and PAI (r = -0.59; p < 0.005) and IGF-I and t-PA activity (r = -0.44; p < 0.05). In a subgroup of nine acromegalics Lp(a) was reduced by 32.2 +/- 6.7% (p < 0.05) after a six-month octreotide therapy and HDL2-cholesterol-concentration increased from 0.17 +/- 0.04 to 0.24 +/- 0.04 mmol/l (p < 0.05). In conclusion, our results demonstrate that elevated Lp(a)-concentrations and changes in fibrinolysis contribute to the cardiovascular complications and should therefore be controlled in acromegalic patients.

Acromegaly↗
PubMed1996

Detection of circulating tissue factor and factor VII in a normal population.

The plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 +/- 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 +/- 15% and the factor VIIag was 0.77 +/- 0.19 microgram/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Adolescent↗
PubMed1995

Plasma concentration of tissue factor and factor VII in patients after abdominal surgery.

Tissue injury following trauma and surgery may induce alterations in blood coagulation and fibrinolysis. Hypercoagulable state after surgery can be associated with the risk of postoperative thromboembolic complications. The contact of coagulation factors with TF after injury of vessel wall and organ tissues may contribute to the development of thrombosis after surgery (1). TF, the cell surface receptor and cofactor of factor VII/VIIa is normally not expressed by cells within the vasculature. Only monocytes and endothelial cells can be stimulated to express TF transiently by a variety of inflammatory and immunological reactions (for review see 2,3). Also surgical treatment was reported to induce TF synthesis in monocytes (4,5,6). TF is present in many extravascular tissues as vascular adventitia, organ capsules, epidermis, colonic mucosal epithelium, liver stroma, pancreas stroma and also on tumor cells (7-12). In this study, we investigated, whether we can detect the release of TF from the traumatized tissues and from activated monocytes into the circulation following abdominal surgery. To test the dependence of the extension of tissue injury during surgery we segregated the patients into group A with major abdominal operations and group B consisting of patients with appendectomy and cholecystectomy. No relationship could be established between changes of TF and postoperative thromboembolic complications.

Abdomen↗
PubMed1992

[Changes in the blood coagulation and fibrinolysis system in the course of normal pregnancy].

In the present study we investigated several factors of hemostasis and fibrinolysis during the normal pregnancy in 52 women. Whereas the Thrombin-Time did not show any change, the increase of the Hepato-Quick and the decrease of the Partial Thromboplastin-Time was significant. During pregnancy we observed a significant increase of the activity of fibrinogen, factor XII and prekallikrein as well as of the von-Willebrand-factor-antigen (VIIIR:Ag). The activity of factor II and X remained constantly. The increased activity of factors of hemostasis was accompanied by an increase of activity and concentration of antithrombin-III. In contrast to the activity of the hemostatic system we could not find any significant alteration of the fibrinolytic system. The cause must be searched in the observed increase of plasminogen-activator-inhibitor (PAI)--likly in combination with a decrease of the tissue-type plasminogen activator (t-PA). Our data indicate, that the highest risk for thrombosis already might exist in week 24 of pregnancy, because a distinct increase of hemostatic activity is combined with a nearly unchanged fibrinolytic activity.

Adult↗
PubMed1991

False-negative prenatal exclusion of Wiskott-Aldrich syndrome by measurement of fetal platelet count and size.

The study of the fetal platelet count and size can, according to the literature, be used for the prenatal diagnosis of the Wiskott-Aldrich syndrome (WAS). So far, no affected fetuses have been identified by this method. All pregnancies in which this method had been applied to resulted, as correctly predicted, in the birth of normal children. Here we report on a familial case of WAS where the haematological parameters failed to reveal the affected second child. Hence we assume that the platelet count and size of platelets remain normal in fetuses with WAS to the gestational age of 22 weeks and cannot be used for prenatal diagnosis.

Adult↗
PubMed1990

[Effect of postprandial lipoprotein fractions on the fibrinolytic system].

Plasma was obtained from fasting normolipemic healthy donors, 150 minutes past fat intake (1 g/kg body weight). Lipoproteins were isolated by sequential and density gradient ultracentrifugation. All lipoprotein fractions from fasting plasma did not show any inhibitory effect of fibrinolysis, whereas postprandial triglyceride-rich fractions (chylomicrons and VLDL) showed inhibitory effects of plasmin induced fibrinolysis. The inhibitor was identified as alpha-2-antiplasmin associated with chylomicrons and VLDL but lipoproteins itself are not responsible for inhibitory effect. It is possible that association is responsible for elevation of alpha-2-antiplasmin in patients with hypertriglycidemia.

Chylomicrons↗
PubMed1988

[Disorders in the contact phase system of blood coagulation as a cause of increased partial thromboplastin time].

Deficiency conditions in the contact phase system of the blood coagulation belong to the rare hereditary defects. Clinically, there is as a rule no inclination to haemorrhage but an increased risk of thrombosis. Therefore, the diagnosis is frequently made on the basis of incidental findings within the framework of routine examinations. Indicating sign is a greatly prolonged partial thromboplastin time (PTT) without clinical signs of haemorrhage. 3 patients with factor XII deficiency are presented and the diagnostic method in prolonged PTT is explained.

Blood Coagulation Tests↗