Contact activation, heparins and cardiopulmonary bypass.
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Biomedical subjects
Publications and source records attributed to W Heller.
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Aprotinin has been used in our hospital in open heart surgery for almost 20 years and recently published studies have revealed a reduction in postoperative blood loss under this therapy. In the present study patients undergoing aorto-coronary bypass operations received either 20,000 KIU aprotinin/kg body weight (group 2) or 60,000 KIU aprotinin/kg body weight (group 3). Another group of patients without aprotinin served as a control (group 1) and postoperative bleeding was more pronounced in these patients compared with the other groups. In parallel, slight reductions in kallikrein-like activity were observed in patients treated with aprotinin. Furthermore, we have shown that the main inhibitor of the contact phase, C1-esterase-inhibitor, loses some of its activity against beta-FXIIa in the presence of heparin. Aprotinin was able to partly antagonize this phenomenon. All studies dealing with the effect of aprotinin in extracorporeal circulation demonstrate hyperfibrinolysis in untreated patients. Aprotinin is known to inhibit plasmin at low concentrations and thus reduced the postoperative bleeding tendency (group 2). In addition, plasma kallikrein is inhibited by high aprotinin concentrations and is responsible for a reduced activation of the contact phase system. This effect led to a further reduction in blood loss (group 3).
PMN elastase concentration of gingival crevicular fluid (GCF) was investigated in 11 healthy volunteers before professional tooth cleaning and after a 5-week period of intensive oral hygiene. GCF was collected using filter paper strips and the enzyme concentration was evaluated by the ELISA-technique. Intensive daily oral hygiene led to a considerable improvement in the clinical indices and to a reduction in the concentration of elastase in GCF. Despite the changes in the oral hygiene status, functional elastase was still present in the samples at the end of the experiment. This could mean that even at clinically healthy sites there is a lack of alpha-1-proteinase inhibitor, the major serum protein inactivating PMN elastase.
Chromogenic peptide substrate assays were used to compare the effects of fractionated and unfractionated heparins on plasma inhibition of alpha and beta FX11a, with and without various concentrations of aprotinin. All of the heparins reduced beta FX11a inhibition at 1 or 2U/ml. Four heparins increased alpha FX11a inhibition. Aprotinin counteracted the reduction in beta FX11a inhibition and augmented the heparin potentiation of alpha FX11a inhibition.
Components of the FX11-kallikrein systems were determined in blood samples from non diabetics and diabetics undergoing cardiopulmonary bypass (CPB). FX11 and prekallikrein levels fell in both groups with the largest falls in the diabetic group. Kallikrein inhibition was also lower in the diabetic group. Alpha-2-macroglobulin levels were lower in the diabetic group before operation and were markedly lower throughout CPB. Kallikrein like activities were also lower in the diabetic group. Beta FX11a inhibition values were higher in the diabetic group and fell in both groups during CPB. From the results obtained we concluded that the lower levels of FX11, prekallikrein, kallikrein inhibition and alpha-2-macroglobulin in the diabetic patients during CPB reflect enhanced activation of the FX11-plasma kallikrein systems. Blood loss in the diabetic group was higher than the for non diabetic group.
1. Denial of illness, mood, eating attitudes, and the responses to visual-constructive tasks were assessed in eight right-handed female patients with restricting anorexia nervosa during the acute phase and following weight gain. 2. A lower body weight and more pronounced anorectic symptomatology were associated with increased left hemispheric activation. 3. Weight gain, greater awareness of negative affect, and overestimation of body parts were correlated with an increase in right hemispheric activation. 4. The results suggest a relationship between anorectic symptomatology and asymmetric brain activation.
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The plasma protein FXII (Hageman factor) has been shown to be linked with the plasma defence systems of coagulation, fibrinolysis, kallikrein-kinin and complement. It can be activated by surface contact activation and in solution. Surface contact activation is a complex phenomenon involving negatively charged surfaces, FXII, high molecular weight kininogen and plasma kallikrein. Fluid-phase activation can be effected by a variety of serine proteases. In both types of activation the FXII zymogen is converted to active enzymes. FXII levels in plasma are low or undetectable in both inherited deficiencies and in a variety of clinical conditions. FXII levels can also be elevated in some clinical conditions. Although discovered as a clotting protein FXII appears to play an important role in the kallikrein-kinin and fibrinolytic systems and also has effects on cells. Recent studies suggest that therapeutic blockade of activation of FXII can be of benefit in certain clinical conditions.
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Whole-blood serotonin (5-HT) and plasma norepinephrine (NE) were studied in 16 autistic children, 21 siblings of autistic children, and 53 parents of autistic children. Both plasma NE and whole-blood 5-HT were negatively correlated with vocabulary performance. Whole-blood 5-HT and plasma NE did not differ between autistic children with or without histories of self-injurious behavior or decreased pain sensitivity. Eighteen subjects were hyperserotonemic (whole-blood 5-HT greater than 270 ng/ml). For these subjects, plasma NE was significantly higher than for subjects without hyperserotonemia. Seven of 10 families with one hyperserotonemic member had two or more hyperserotonemic members. Observations of familiarity of whole-blood 5-HT suggest that larger-scale and more focused study of whole-blood 5-HT as a possible genetic marker may be productive.
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