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Biomedical subjects

M Samama

Publications and source records attributed to M Samama.

At least 253 records · Page 14Linked to original sources
PubMed1978

[Congenital dysfibrinogenaemia. Two new cases (author's transl)].

Congenital dysfibrinogenaemia is a rare disorder related to an abnormality in the behaviour of the fibrinogen molecule. The diagnosis may be made with the aid of simple tests, including prothrombin'time, even though this examination may be normal in a small number of cases. Two new cases are reported here. Neither of the two women involved had a past history of severe haemorrhage, the diagnosis being made at the time of routine coagulation studies. According to the international nomenclature, we suggest the names fibrinogen Paris IV and fibrinogen Buenos-Aires II. In order to avoid missing the diagnosis, fibrinogen should be estimated by different methods in the presence of hypofibrinaemia. There is disagreement between fibrinogen levels estimated by the thrombin chronometric method, in general low, and levels obtained by gravimetric and immunological methods, usually normal.

Adolescent↗
PubMed1978

[Platelet volume in essential thrombopenia].

The electronic method for measuring platelet volume using the Coulter Z BI Counter coupled with a Channelyser C 1000 has been standardized. The distribution of platelet volumes was studied in 28 cases of idiopathic thrombocytopenic purpura (ITP) and in 59 cases of thrombocytopenia attributed to a failure of platelet production. Results showed that the volumetric distribution curve of platelet rich plasma (PRP) was altered in 40 cases, by the presence of small particles interfering with platelets of small volume and/or by residual red cells modifying its terminal segment. These abnormalities seem linked to the degree of thrombopenia, but independent of its central or peripheral origin. A method of isolation and concentration of platelets in an albumin gradient allowed the restoration of the classical volume distribution in 24 cases out of 40. Simulated thrombopenias obtained by dilution of platelets in their own platelet poor plasma (PPP) showed that the abnormalities in the small volume range could be reproduced in vitro by modifying the proportion of platelets and of small residual elements in the PRP. When the albumin gradient method was used, the classical distribution of platelet volumes was found. Preliminary electron-microscopy studies show that the small elements in the PRP of thrombopenic subjects could be formed by red cell fragments. Cytoenzymologic studies should be able to confirm this. Volumetric parameters were determined from the asymmetric and unimodual distribution of platelets, either directly on PRP or after concentration and separation of platelets in an albumin gradient. They showed that platelet volumes were very often increased in ITP but also occasionnally in thrombopenia of attributed to a failure of production.

Blood Platelets↗
PubMed1978

[Trial of an automatic apparatus for coagulation : Auto-Fi Dade (author's transl)].

Auto-Fi Dade has been used for thromboplastin time, activated partial thromboplastin time, fibrinogen determination and a few determinations of factors V, VII + X, II and VIII. The results of the thromboplastin time, using Dade Tromboplastin or thromboplastins from two other commerical firms, show a coefficient of variation (CV) ranging from 1.11 to 3.43% for short times and 1.97 to 2.64% for longer times.

Afibrinogenemia↗
PubMed1978

[Thrombolytic treatment (theoretical basis, therapeutic protocols, monitoring)].

Thrombolytic therapy is aimed at dissolving thrombi. Streptokinase (SK) and urokinase (UK) are currently used in France but their mode of action has not been completely elucidated, which renders the establishment of therapeutic protocols and the choice of doses difficult. This treatment has a certain number of contraindications which must be strictly respected. The effectiveness of SK and UK in high doses has been demonstrated, in particular in pulmonary embolism and acute arterial obstruction of the limbs, but there is a risk of haemorrhage, whilst UK in moderate doses is usually well tolerated but has yet to prove its effectiveness in randomised double blind trials. Laboratory control has been simplified but it is essential not to forget the importance of clinical monytoring. Finally, drugs have recently been used in association with thrombolytics and more particularly the administration of plasminogen or defibrinating agents before or after thrombolytics.

Arterial Occlusive Diseases↗
PubMed1977

[The detection of soluble fibrin complexes by a haemagglutination test. Clinical applications (author's transl)].

Testing for soluble fibrin complexes was performed using a sensitive and reliable haemagglutination assay, with red cells sensitized by fibrin monomers. The principle is based on the fact that the monomers linked to red cells and induce their agglutination. This test, used in clinical trials, has revealed the presence of soluble complexes in every confirmed case of acute DIC, but also in Chronic DIC where diagnosis is difficult to establish (negative ethanol gelation test, normal or sub-normal levels of fibrin breakdown products). In Cirrhosis of the liver, the test gives positive results in a non negligible number of cases. Several hypotheses are made to explain why in certain confirmed cases of DIC, low fibrin breakdown products levels are found.

Aged↗
PubMed1977

[Antivitamin K].

Explore the source record for details and available documents.

Anticoagulants↗
PubMed1977

[Volume distribution studies on the platelet populations (author's transl)].

The volume distribution into human platelet populations was investigated in order to determine if thereis a relationship between the cell density and the cell size and if the isolated platelets are homogeneous populations of cells. The platelet populations were isolated from platelet rich plasma or from washed platelets by isopycnic centrifugation on sucrose density gradients. Platelet volume was measured electronically with Coulter F or Coulter Z Bic coupled with Channelyser C 1000. The results show that there exists a direct relationship between platelet density and size, since the volumetric parameters gradually increase from the small platelets of lower density to the larger ones isolated at higher density. Evidence was also obtained that the isolated populations of platelets were heterogeneous and their volume distribution was log-normal. Both the heavy and the light platelet populations were found as a mixture of mainly large or mainly small platelets respectively.

Blood Platelets↗
PubMed1977

[Study of the bleeding mechanism during fibrinolysis induced by streptokinase in the rabbit (author's transl)].

Our aim in this work has been to obtain precisions on the bleeding mechanism during fibrinolysis induced by streptokinase in the rabbit. Haemostasis was studied in vivo by the method oh Honour and Russell. The injection of 40 000 u/kg of streptokinase in 10 minutes induces rapidly fibrinolysis, which lasts for approximately one hour which is not accompanied by changes either in coagulation factors, or in platelet function. In vivo : . the adhesion of platelets to the vascular lesion is normal; . platelet aggregation is normal as is the formation of intravascular thrombi; . on the other hand the intra mural platelet thrombus is unstable. The embolization of the intravascular thrombi is responsible for new hemorrhages which can be correlated with the intensity of fibrinolysis. Thus, even in the absence of fibrinogenolysis, of fibrinogen degradation products FPD, of abnormal thrombin generation and of altered platelet function, the fibrinolytic activity induced by streptokinase could alone be responsible for bleeding episodes, occuring during thrombolytic treatment by streptokinase in man.

Animals↗