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Biomedical subjects

S Valentin

Publications and source records attributed to S Valentin.

23 records · Page 2Linked to original sources
PubMed1991

Inhibition of extrinsic pathway inhibitor shortens the coagulation time of normal plasma and of hemophilia plasma.

An increasing amount of evidence suggests that coagulation factors VIII and IX play a role not only in the intrinsic but also in the extrinsic pathway of coagulation. In this context the influence of the Extrinsic Pathway Inhibitor (EPI) on the coagulation time of hemophilia plasma lacking FVIII or FIX has been investigated. The coagulation time was measured in a dilute thromboplastin assay. Addition of recombinant EPI (rEPI) prolonged the coagulation time of normal plasma while the addition of an inhibitory antibody against EPI shortened the coagulation time. At low concentrations of thromboplastin the coagulation time of hemophilia plasma was prolonged and at all dilutions of thromboplastin, addition of anti-EPI IgG normalized the coagulation time of a hemophilia plasma. Analysis of 10 individual donor plasma samples and 8 individual hemophilia samples showed that addition of anti-EPI IgG shortened the coagulation time more in hemophilia plasma than in normal plasma. This illustrates the importance of a powerful extrinsic FVII dependent pathway to achieve hemostasis in the case of FVIII or FIX deficiency (hemophilia A and B).

Antibody Specificity↗
PubMed1991

Prevention of recurrent variceal bleeding in alcoholic cirrhotic patients: prospective controlled trial of propranolol and sclerotherapy.

We conducted a prospective randomized controlled study to evaluate the effectiveness of propranolol and sclerotherapy, compared to a control group, in the prevention of variceal rebleeding in alcoholic cirrhotic patients. Among the 79 patients included, the distribution of patients according to Child-Pugh classification was: A, 22%; B, 40%; and C, 38%. Propranolol was given twice daily with a mean final dose of 54 +/- 16 mg/day, this resulted in a mean reduction in resting heart rate of 26 +/- 7%. Sclerotherapy was performed weekly using 1% polidocanol. End points were rebleeding or death. During the mean follow up of 19 +/- 16 months, 43 patients bled and 22 patients died. The cumulative percentages of patients free of rebleeding at 1 year were: propranolol, 81% (95% confidence interval (CI): 63-92); sclerotherapy, 64% (95% CI: 45-82); control, 54% (95% CI: 36-71); these differences did not reach statistical significance. The cumulative percentages of patients alive at 1 year were: propranolol, 92% (95% CI: 76-98); sclerotherapy, 79% (95% CI: 58-91); control, 81% (95% CI: 60-93); these differences were not statistically significant. Alcohol withdrawal, which occurred in 66% of patients, was an independent predictive factor associated with a decreased risk of rebleeding or death. In conclusion, a life table analysis of patients free of rebleeding, as well as of patients surviving, revealed a tendency in favour of propranolol. The lack of a statistical support for these two favorable effects could be due to poor statistical power.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1991

Simultaneous presence of tissue factor pathway inhibitor (TFPI) and low molecular weight heparin has a synergistic effect in different coagulation assays.

Injection of heparin releases tissue factor pathway inhibitor (TFPI) to the blood and, after heparin neutralization, it has been recently demonstrated that the released TFPI has an anticoagulant activity. Using recombinant TFPI (rTFPI) we have investigated how the simultaneous presence of TFPI and low molecular weight heparin (LMW heparin) affects different coagulation assays. Coagulation was measured using the activated partial thromboplastin time, the prothrombin time and a dilute tissue factor assay. The anticoagulant activity of partly purified plasma TFPI (pTFPI) was much higher than that of TFPI. However, this high anticoagulant activity was unstable, so in order to investigate the effect of pTFPI and LMW heparin we used an inhibitory antibody towards TFPI and looked at the effect of removing TFPI from plasma. When both rTFPI and LMW heparin was added to plasma a synergistic effect was observed in all assays. In the tissue factor dependent coagulation assays, the effect of adding rTFPI or removing pTFPI was more pronounced in the presence of heparin. TFPI plays a significant role in assays where the coagulation time is prolonged for some reason. This may be caused by dilution of tissue factor, by the presence of heparin or by a defect in the coagulation cascade such as that seen in haemophilia.

Blood Coagulation Tests↗
PubMed1991

[Reconstruction of the medial canthus in oncology. Apropos of 105 cases over 9 years].

Without forgetting that resection of a malignant tumour must always take priority over the problems of reconstruction, based on a series of 105 cases of medial canthus lesions, the authors believe that: for tumours with a reserved prognosis, particularly sclerodermiform basal cell carcinomas of the orbit, full thickness skin graft is the most appropriate technique; for cases with a good prognosis, the cosmetic result takes priority. An intersuperciliary island flap is currently the method of choice; for advanced cancers of the medial canthus, the combination of frontal flaps and nasolabial flaps is the procedure which gives the best aesthetic and functional results. This series includes three cases of radical orbital exenteration, including two because of sclerodermiform basal cell carcinomas, and the authors stress the very serious prognosis of these tumours in the orbit, especially in the presence of a recurrence in an irradiated territory.

Adult↗