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Biomedical subjects

J Radwan

Publications and source records attributed to J Radwan.

At least 19 recordsLinked to original sources
PubMed1992

Antiplatelet drugs and generation of thrombin in clotting blood.

Platelets participate in formation of thrombin through secretion of coagulation factors and by providing a catalytic surface on which prothrombinase complex is assembled. We studied the effects of four antiplatelet drugs on thrombin formation in healthy volunteers. Thrombin generation was monitored both in vitro--in recalcified plasma--and ex vivo--in blood emerging from a standardized skin microvasculature injury, which also served to determine bleeding time. A mathematical model has been developed to describe the latter reaction. It is based on estimation of the rate of increase in fibrinopeptide A (FPA), a specific marker of thrombin activity, in blood emerging from skin incisions. Two hours after the ingestion of 500 mg of aspirin, thrombin formation became significantly impaired both in vitro and ex vivo. In contrast, 2 hours after the oral administration of placebo, indomethacin 50 mg, or OKY-046 (a thromboxane synthase inhibitor) 400 mg, thrombinogenesis remained unaltered. Ticlopidine, studied either 3 hours after 500 mg oral administration, or after 5 days of intake at a daily dose of 500 mg, had no effect on thrombin generation. Thus, aspirin, contrary to other antiplatelet drugs, depresses thrombin formation in clotting blood, a phenomenon that might be of clinical relevance. It is suggested that aspirin exerts this effect by acetylating prothrombin and/or macromolecules of platelet membrane.

Adult↗
PubMed1992

Persistent generation of thrombin after acute myocardial infarction.

During the acute phase of myocardial infarction, the generation of thrombin is reflected in the sudden rise of fibrinopeptide A (FPA) and the thrombin-antithrombin III (TAT) complex in blood. We have systematically determined the FPA and TAT plasma concentrations over a period of 14 days after acute myocardial infarction in 100 patients. Mean levels of both thrombin markers were the highest on admission, remained elevated over the following few days, and then gradually declined after day 5. Still, by the end of the first week two thirds of the patients had distinctly elevated TAT and FPA levels, and by the end of the second week such an abnormality was present in half of them. Continuous intravenous heparin infusion at a dose of 20,000 units/day, administered for 1 week to patients who had either received (n = 21) or not received (n = 17) streptokinase, led to a significant depression (p less than 0.05) of thrombin markers over the first 48 hours, an effect that did not persist over the subsequent days of treatment. In patients not assigned to heparin treatment, those in heart failure had significantly (p less than 0.05) higher mean TAT and FPA values on days 3, 5, and 7 compared with patients in whom heart failure was absent. Infarct extension, pulmonary embolism, and death were also associated with a rise in one or both thrombin markers, often preceding the onset of clinical symptoms. Thrombinogenesis was not accompanied by changes in mean plasma concentrations of prothrombin, antithrombin III, or alpha 2-macroglobulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗
PubMed1991

[Lipoproteins (A) after a history of myocardial infarction, arteriosclerosis obliterans, hypertension and hyperlipidemia].

Serum lipoprotein(a) concentration in men with hypertension, arteriosclerosis obliterans, hypercholesterolemia and after myocardial infarction was measured using Laurell's immunoelectrophoresis. Lp(a) distribution and mean serum concentrations did not differ significantly from the controls, with the exception of a group of premature myocardial infarction (age below 45), in which high values were more frequent.

Adult↗
PubMed1990

[Sex chromosome aberrations in patients with menstruation disorders].

We studied 150 women with primary/secondary amenorrhea and/or oligomenorrhea; in 61 cases we found an abnormal karyotype (i.e. 40.7%): 51 cases in the first group of 110 patients with amenorrhea (i.e. 46%) and 10 cases in the second group of 40 patients with oligomenorrhea and/or secondary amenorrhea (i.e. 25%). The chromosome aberrations we found consisted in X aneuploidy, male karyotype and the different structural changes as mono- and dicentric X isochromosomes, dicentric, ring, deleted or inverted X chromosomes. Our results suggest a cytogenetic examination in patients with primary amenorrhea as well as in patients with oligomenorrhea and/or amenorrhea secundaria.

Adolescent↗
PubMed1989

[New possibilities of treating acute angioedema caused by C1-inhibitor deficiency].

The authors discuss diagnostic difficulties in 12 cases of hereditary angioneurotic edema due to C1-esterase inhibitor (C1-INH deficiency). Emphasis is on the treatment of the acute attacks with intravenous infusions of C1-inhibitor concentrate (Boehring, West Germany). This proved to be a very efficient and safe therapy, leading to a prompt disappearance of all clinical symptoms. Throughout 12 months following the infusions, indices of the liver function remained within the normal range, and anti-Hbs and anti-HIV tests were negative.

Acute Disease↗
PubMed1987

Specific immunotherapy in hay fever.

The observation included 120 patients suffering from hay fever (HF) in age 18-58. In 77 of them specific immunotherapy (SI) with pollen vaccine was applicated through 3 consecutive years, while 43 patients remained without this form of therapy, as a control group. SI was efficient in 47% of treated patients, and in these cases IgE value came back to normal value, the IgG level increased and suppression of skin test to pollen allergens was observed. In 17% of treated patients side effects appeared during SI and together with exacerbation of HF, an increase of skin reaction to pollen allergens was noted.

Adolescent↗