[Evaluation of an automatic clot-sensing instrument : Coag A Pet 200 (author's transl)]

The Coag A Pet 200 is an automatic clot-sensing instrument, with two channels; the variation in the optical density is detected by a photoelectric system. The results are sequentially printed out with the sample number. A critical evaluation of its performance in hospital use over 7 month, is reported. The series of tests thus automated consists of: one stage prothrombin-time, Owren test, activated partial thromboplastin time, analytical determinations of factors II, V, VII + X, VII, IX, XI, XII. The repeatibility is good: CV ranged between 0.5 to 1.5% or 2%, and a high degree of correlation with the standard manual techniques was found: R: 0.93 TO 0.99. This instrument was easy to master, use and maintain.

[Electra 600 d : results of a three year study (author's transl)]

Electra 600 D has been used in our laboratory for 3 years. The Quick's prothrombine time is the only test routinely performed with satisfactory results. The measure of activated partial thromboplastin time, the assays of factor II, factor V and complex VII + X are unsatisfactory, probably because of the type of the reagents which are used.

Insensitivity of factor V and factor Va to diisopropylfluorophosphate and antithrombin III

Bovine plasma Factor V and Factor Va, the latter prepared by thrombin or venom activator action on Factor V, are not inactivated by diisopropylfluorophosphate or antithrombin III nor do they form identifiable complexes with either of these reagents. On the basis of these data, it is concluded that bovine Factor V and Factor Va are not serine proteases.

[The effect of oral contraceptives on levels of thyroid hormone, blood coagulation and ceruloplasmin (author's transl)]

The effect of various hormonal contraceptives on the thyroid hormone level, plasmatic and thrombocytic coagulation, cholesterol and ceruloplasmin levels and the activity of gamma-glutamyl transpeptidase was investigaged by the changes produced by long term cyclic estrogen-gestagen therapy on the metabolism of the organism. The free thyroxine index and the total cholesterol were within the normal range. The thyroxine binding index at 44% was above the normal level and the mean value was significantly raised. The ceruloplasmin concentration in the serum was also significantly increased. Pointers to a general hypercoagulability could not be ascertained with a statistical significance.

Platelet preservation V. Survival, serotonin uptake velocity, and response to hypotonic stress of fresh and cryopreserved human platelets

The survival in vivo of 51Cr-labeled autologous human platelets, the serotonin uptake velocity, and the response to hypotonic stress were determined both before and after cryopreservation. Changes in platelet survival corresponded to changes in serotonin uptake velocity and response to hypotonic stress. No correlation was observed between the values of the survivla in vivo, the serotonin uptake velocity, and the response to hypotonic stress within the separate suspensions of fresh and cryopreserved platelets. There was no indication that hypercoagulability was induced by infusion of small amounts of cryopreserved platelets.

Platelet aggregation as a sign of septicemia in thermal injury. A prospective study

Serial measurements of coagulation activity, platelet counts, and platelet aggregation were done in patients with full-thickness burns involving 25% or more of body surface area to detect specific changes that might correlate with the onset of septicemia. Mean and maximal values for prothrombin time, partial thromboplastin time, thrombin time, activities of factor V and factor VIII, and concentrations of fibrinogen and fibrinogen-related antigens observed in the presence of bacterial septicemia did not differ significantly from those observed in the absence of septicemia. Mean platelet counts were significantly less with sepsis, but values in individual subjects were not indicative of the presence of septicemia. By contrast, platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen always became severely abnormal with the onset of septicemia but not in the absence of sepsis.

Acquired inhibitors in nonhemophilic patients

The occurence, the biological, biochemical and immunological properties of spontaneous inactivating inhibitors (directed against factors VIII, V or XIII) and of interfering inhibitors (inhibiting prothrombin activation) are reviewed. The clinical implications and therapy of these inhibitors are discussed with special reference to the management of patients with spontaneous factor VIII inhibitors.

Stability of freeze-dried plasma prepared from patients on oral anticoagulants

The suitability of freeze-dried plasmas from patients on oral anticoagulants to serve as reference material in the calibration of thromboplastins used in the control of oral anticoagulant treatment was assessed in two centres. One pooled normal plasma and four pooled plasmas from patients at different levels of anticoagulation were collected into HEPES-citrate containing Trasylol. The plasmas, in 1 ml volumes, were freeze dried in siliconized ampoules under the optimal conditions used for biological standards. Small aliquots of the same plasmas were stored at -70 degrees C. Five different thromboplastins were used to carry out the tests on these plasmas. There was little difference in the clotting times obtained with five reference thromboplastins (two human, two rabbit, and one bovine reagent) on frozen and freeze-dried plasma, if the latter was tested immediately after complete reconstitution or within six hours of reconstitution if kept at +4 degrees C. Reconstituted plasmas showed a marked shortening of clotting times when stored at 22 and 37 degrees C if thromboplastins sensitive to activation of factor VII were used. In contrast, when thromboplastins sensitive to factor V were used, prothrombin times in plasmas stored at 22 and 37 degrees C became prolonged due to the loss of factor V.Freeze-dried plasmas from patients on oral anticoagulants can be used to calibrate thromboplastins, provided they are used immediately after complete reconstitution or kept at +4 degrees C for use within four to six hours of reconstitution.