[Evaluation of coagulation factor XIII. Critical study of the different techniques used (author's transl)]

A critical study of various techniques of factor XIII determination was performed. The method using dansyl-cadaverin seems to be the most sensitive one but not easily usable in routine tests. The biological techniques using factor XIII-free fibrinogen (screening test and classical test) are satisfactory in clinical trials but are not sensitive for the detection of moderate deficiency of factor XIII. The immunological tests used are the electro-immuno-diffusion test and the test of the consumption of an anti-serum. However, only the antibody directed against the sub unit. A must be used. All these techniques were performed in acquired deficiency of factor XIII and a good correlation was obtained. However, in factor XIII congenital deficiency, we propose to associate a biological assay and the antigenic determination of factor XIII in order to detect a possible abnormal factor XIII.

[Metabolic control in 107 maturity onset diabetic out patients (author's transl)]

Hemoglobin A1c concentrations were measured in 107 out patients with non insulin treated diabetes. A good correlation was observed between Hb A1c and random post-prandial plasma glucose levels. Mean Hb A1c concentrations were slightly higher in these diabetics than in controls but markedly lower than values observed in insulin treated patients. Sixty three per cent of the patients had Hb a1c levels below three standard deviations above our normal mean value. Random post-prandial plasma insulin levels were correlated to the degree of overweight but not other parameters. The best results were observed in patients treated by diet alone (31 % of the whole population) and in those on diet and sulfonylureas (30 %) who were also the less older and the less overweight subjects.

Fibrinogen Marseille. A new case of congenital dysfibrinogenaemia

A new case of congenital dysfibrinogenaemia was found in 2 members of the same family. The anomaly was characterized by an abnormal polymerization of fibrin monomers, whereas the release of fibrinopeptides by thrombin and fibrin stabilization by F XIII were normal. Investigation of the fibrinogen molecule did not lead to localizing the structural abnormality.

A New Inhibitor of Factor XIII and Platelet Aggregation. Influence of Fibrin Stabilization on Thrombolysis

Antifactor XIII and antiplatelet aggregation activities were discovered in vitro for a synthetic compound with a benzothiophen keton structure. It was found to inhibit the stabiliiation of fibrin as shown by S.D.S. Polyacrylamide gel electrophoresis of a clot previously dissociated by urea and mercaptoethanol, among other tests. The mechanism of action was studied using dansyl cadaverin incorporation into casein : the inhibitor effect was not competitive, related to the inactivation of factor XIIIa, and independant of calcium concentrations. It was much more pronounced in a purified system than in plasma, due to its binding to albumin. We therefore studied its possible displacement from albumin by various drugs.

The thrombolytic activity of urokinase only slightly increased when clot stabilization was inhibited by the studied compound.

Abnormalities in Fibrin Formation in Hepatic Disease. Consequences of Acquired Dysfibrinogenemia on Fibrin Formation and on Platelet Aggregation Cofactor Activity

Different causes of abnormal fibrin formation can be identified in severe hepatic diseases.

A decrease in the level of Aα band of isolated fibrinogen can be related to increased fibrinolysis.

Soluble complexes detected by the haemagglutination assay of red blood cells sensitized with fibrin monomers are present in cases with associated intravascular coagulation. An abnormal fibrin monomers aggregation can be due either to a plasma inhibitor or to dysfibrinogenemia. The anomaly is only present in plasma in the former case and in both plasma and isolated fibrinogen in the latter case.

In acquired dysfibrinogenemia an increase in sialic acid content in the fibrinogen molecule can be demonstrated and is associated with an increase of ADP platelet aggregation cofactor activity. The effect of desialidation was also studied. These results are in good correlation with the hypothesis that oreviously isolated fibrinogen glycopeptides might play an important, roie in platelet aggregation.

Plasminogen Activity in Plasma and in Serum Before and After Venostasis

When venostasis is applied in men for 10 minutes at a pressure half-way between diastolic and systolic, various results may be obtained as far as fibrinolysis is concerned, normally the euglobulin lysis time reduced from above 3 hours to less than one hour. In these conditions, after venostasis the estimation of plasminogen after activation by Streptokinase (S.K.) on synthetic substrate S2251, shows 20-80% greater activity in serum than in plasma. In some patients at high risks of thrombosis, the euglobulin lysis time 15 unchanged after venostasis. In these cases, the biological activity of plasminogen is slightly greater in plasma than in serum, as is observed before venostasis in all subjects.

In order to explain these observations, experiments were performed using placental or plasmatic (glu or lys) plasminogen ; these show that for the same antigen activity, the biological activity of placental plasminogen previously activated by S.K. is greater than that of plasmatic plasminogen. We suggest a modification of the structure of plasminogen in the presence of activators and of fibrin clots. Further experiments will be necessary to explain the modification of plasminogen structure

[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.

Glycosylated haemoglobin concentrations and clinitest results in insulin-dependent diabetes

In 11 insulin-dependent diabetic outpatients, haemoglobin AIc (HbAIc) was measured by an electrofocusing method. Diabetic control was evaluated by the semiquantitative urine test for sugar, 'Clinitest', three times a day every day in the 8 weeks before the HbAIc determination. 24-hour glycosuria and fasting and postprandial blood-glucose levels were measured one to five times during this period. The HbAIc concentration correlated highly with the semi-quantitative urinary-sugar-concentration index but not with the other parameters.

Effect of clomiphene on prolactin secretion and lactation in puerperal women

Clomiphene citrate treatment neither inhibited milk secretion nor had a suppresive effect on serum prolactin levels in 10 puerperal women.

Spin label studies of ATP phosphoribosyltransferase of E. coli

Covalently bound bromoacetamide nitroxides have been used to detect the conformational changes and enzyme association induced by its feedback inhibitor, histidine.

Gonadotropic responsiveness to clomiphene, LRH, estradiol, and bromocriptine in galactorrheic women

Twenty hyperprolactinemic patients with galactorrhea were studied to determine their gonadotropic responses to various stimuli. Five women lacked response to gonadotropin following the administration of clomiphene citrate. Ten patients who had luteinizing hormone releasing hormone (LRH) tests before and during bromocriptine administration exhibited varied FSH and LH responses that apparently were unaffected by bromocriptine therapy. A loss of the normal positive feedback of estrogens at the level of the hypothalamus was demonstrated in most patients before and during bromocriptine therapy. Long-term treatment with bromocriptine in 11 women resulted in a decrease of serum prolactin, cessation of lactation in all, and pregnancy in 8. These results suggest that the failure of normal secretion of gonadotropins in hyperprolactinemic women may result from 1) inadequate release of endogenous LRH, and 2) loss of the positive feedback of estrogens, as a result of the same hypothalamic disturbance that provokes the hyperprolactinemia. In turn, the elevated prolactin levels may exert a short-loop negative feedback at the hypothalamic level, inhibiting cyclic gonadotropin release.