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Biomedical subjects

A Zivelin

Publications and source records attributed to A Zivelin.

66 records · Page 4Linked to original sources
PubMed1986

Immunologic and biochemical characterization of homozygous and heterozygous Glanzmann thrombasthenia in the Iraqi-Jewish and Arab populations of Israel: comparison of techniques for carrier detection.

To define biochemically and immunologically the platelet defect in Iraqi-Jews and Arabs with Glanzmann thrombasthenia in Israel, we tested the platelets of 32 thrombasthenics and 37 obligate carriers from 19 families with affected members. Thrombasthenic platelets were devoid of glycoprotein IIb (GPIIb) as judged by polyacrylamide gel electrophoresis and devoid of the GPIIb/IIIa complex as judged by radio-electroimmunoassay. Binding of a murine monoclonal antibody directed at GPIIb and/or GPIIIa to intact thrombasthenic platelets averaged less than 2% of the control value. Evaluation of the number of molecules of antibody bound per platelet permitted discrimination between controls and obligate carriers with a high degree of accuracy (sensitivity = 91.9%, specificity = 92.3%). Obligate carriers could also be discriminated from controls by determining the ratio of GPIIb to GPIb by polyacrylamide gel electrophoresis and by quantifying the GPIIb/IIIa complex by radio-electroimmunoassay. These studies indicate that the thrombasthenics in Israel have the severe form of the disease (type I) and that the platelets of heterozygotes have significantly reduced amounts of both total and surface-exposed GPIIb and/or GPIIIa.

Adolescent↗
PubMed1985

Inhibition of tissue factor/factor VIIa activity in plasma requires factor X and an additional plasma component.

A study was carried out to explore requirements for the inhibition of tissue factor-factor VIIa enzymatic activity in plasma. Reaction mixtures contained plasma, 3H-factor IX or 3H-factor X, tissue factor (vol/vol 2.4% to 24%), and calcium. Tissue factor-factor VIIa activity was evaluated from progress curves of activation of factor IX or factor X, plotted from tritiated activation peptide release data. With normal plasma, progress curves exhibited initial limited activation followed by a plateau indicative of loss of tissue factor-factor VIIa activity. With hereditary factor X-deficient plasma treated with factor X antibodies, progress curves revealed full factor IX activation. Adding only 0.4 micrograms/mL factor X (final concentration) could restore inhibition. Inhibition was not observed in purified systems containing 6% to 24% tissue factor, factor VII, 0.5 micrograms/mL, factor IX, 13 micrograms/mL, and factor X up to 0.8 micrograms/mL, but could be induced by adding barium-absorbed plasma to the reaction mixture. Thus, both factor X and an additional material in plasma were required for inhibition. The amount of factor X needed appeared related to the concentration of tissue factor; adding more tissue factor at the plateau of a progress curve induced further activation. These results also indicate that inhibited reaction mixtures contained active free factor VII(a). Preliminary data suggest that inhibition may stem from loss of activity of the tissue factor component of the tissue factor-factor VII(a) complex.

Barium↗
PubMed1984

Homozygous protein C deficiency manifested by massive venous thrombosis in the newborn.

We studied a family in which two infants had died with massive venous thrombosis shortly after birth. Protein C antigen was undetectable by immunologic assays of plasma available from one infant. (Protein C is a potent naturally occurring anticoagulant that inactivates activated coagulation factors V and VIII). The parents, who were first cousins, both had partial protein C deficiency. Reduced protein C levels were also observed in 12 of 25 additional family members. None of the partially deficient family members (age range 4 to 70 years) had thrombotic episodes. Our data support the view that hereditary protein C deficiency is an autosomal disorder in which the homozygous state may be manifested by the virtual absence of plasma protein C and by fatal thrombosis in the neonatal period.

Adult↗
PubMed1984

Hereditary factor XIII deficiency: report of four families and definition of the carrier state.

Definition of the carrier state of hereditary factor XIII deficiency was attempted by a study of four unrelated families with patients affected by the disease. Ten homozygotes, 14 obligatory carriers and 20 suspected carriers were available for determination of plasma factor XIII subunits A and B levels (by electroimmunoassay) and for assay of factor XIII enzymatic activity (by 14C-putrescine incorporation into casein). Evaluation of the ability of seven variables related to these tests to discriminate between healthy controls and obligatory carriers disclosed that two variables related to the enzymatic assay classified correctly 92.9% of the carriers and 73.3% of the controls, whereas the variables related to subunit A had a lower discriminative ability. Entering both enzymatic and immunologic variables into the discriminant function did not improve the result of the former. A classification function was established from which the posterior probability of suspected carriers can be determined by measuring the incorporation of 14C-putrescine into casein at 90 min after adding the labelled amine.

Caseins↗
PubMed1983

Cold-promoted activation of factor VII: is It a problem under blood bank conditions?

Transfusion of blood or plasma kept at 4 degrees C for 12-14 h could be hazardous since about 15% of plasmas from healthy donors undergo cold activation of factor VII under such conditions. In this study we were unable to demonstrate in plasma from 209 healthy donors a significant rise in mean factor VII level after storage of plasma in the blood bank bags at 4 degrees C for 24 h. The blood bank unfavorable conditions for cold activation of factor VII were manifested in the plasma from a known cold activator whose plasma underwent cold activation in a plastic test tube while in the blood bank bag it did not. The lack of cold activation observed in blood bank versus laboratory conditions did not stem from differences in anticoagulant, in speed of centrifugation, in proportion anticoagulant-blood or in the plastic ware; it appeared to stem from differences in the ratio between plasma volume and surface of the containers used in the blood bank versus the laboratory. Since plasma factor VII from 3 out of 16 women taking contraceptives became activated in the cold even at relatively small surface exposure it seems advisable to separate and freeze as fast as possible plasma components from blood donated by women on contraceptives.

Blood Banks↗
PubMed1979

Detection of Haemophilia A carriers by replicate factor VIII activity and factor VIII antigenicity determinations.

Factor VIII (fVIII) activity and antigenicity were determined on replicate fresh blood samples drawn on three separate occasions in 48 normal females and 37 obligatory haemophilia A carriers, in an attempt to improve the detection rate. fVIII activity was assayed by a one-stage method and fVIII antigenicity by the Laurell's technique employing an anti-fVIII antiserum prepared in rabbits. The mean results for the individual subjects were analysed after establishing a discriminant function. The probability of being a carrier was determined on the basis of laboratory data and family history. The probability data were translated into more simple terms applicable for genetic counselling by defining three categories: Definite carriers, doubtful carriers and definite normals. Of the obligatory carriers, 83.8% were classified definite carriers, 13.5% doubtful carriers and 2.7% as definite normals. Of the normal females, 4.2% were classified as definite carriers, 18.7% doubtful carriers and 77.1% as definite normals. Adjustment of the results according to age was found unnecessary. The precision of the determinations of fVIII antigenicity and fVIII activity in individual subjects was calculated for different numbers of replicate tests performed in the same individual. It was found that if only one test is performed, a substantial error might occur. Three replicate tests considerably diminish this error, although it is still in the range of +/- 16--29%. For suspected carriers who fall in the doubtful category it is suggested that six or even more tests are performed.

Adolescent↗
PubMed1976

Fibrinogen response to turpentine and endotoxin in busulfan-treated rabbbits.

The response of the plasma fibrinogen level to the subucutaneous injection of turpentine and to the intravenous injection of endotoxin was measured in normal rabbits and in rabbits made granulocytopenic and thrombocytopenic with busulfan. Plasma fibrinogen levels rose sharply in both normal and busulfan-treated rabbits and the extent of the rise in fibrinogen level after turpentine. As discussed herein, these data are consistent with the hypothesis that material from granulocytes plays a pathophysiologic role in the stimulation of fibrinogen synthesis in inflammation and after tissue trauma.

Agranulocytosis↗
PubMed1975

Fibrinogen levels after inflammation or endotoxin in normal and hypophysectomized rats.

The hypothesis that pituitary hormones are required for increased fibrinogen synthesis after inflammation or endotoxin was tested by measuring plasma fibrinogen concentrations after inflammation or endotoxin in normal and hypophysectomized rats. Animals were divide into groups receiving no exogenous adrenal steroids, low-dose adrenal steroids, or high-dose adrenal steroids. Hypophysectomy failed to prevent fibrinogen levels from rising after intramuscular turpentine (mean 240 mg/100 ml prior to and 556 mg/100 ml 24 h after turpentine). Steroids did not suppress this rise. Endotoxin, 5 mug/100 g, caused a marked rise in fibrinogen in normal rats at 24 h (mean 296 mg/100 ml before endotoxin and 554 mg/100 ml after endotoxin). This dose of endotoxin killed hypophysectomized rats within 12 h. Hoevr, if hypophysectomized rats were protected with high-dose adrenal steroids, then 5 mug of endotoxin per 100 g caused the same fibrinogen rise as in normal rats (mean 299 mg/100 ml before endotoxin and 587 mg/100 ml after endotoxin). Aparently, pituitary hormones are not necessay for increased fibrinogen synthesis after either inflammation or endotoxin in the rat.

Animals↗
PubMedDate not supplied

Factor VII in plasma of women taking oral contraceptives. Lack of cold activation under blood bank conditions.

Factor VII in plasma from about 15 percent of healthy subjects undergoes activation when samples are kept in plastic tubes at 4 degrees C. In women taking oral contraceptives, this phenomenon is observed much more frequently. If this phenomenon occurred under blood bank conditions as well, the transfusion of such plasma from donors taking oral contraceptives to patients afflicted by trauma could enhance thromboembolism. Plasma packs of 72 female donors taking oral contraceptives were separated and stored at 4 degrees C for 24 hours in the blood bank. No significant change in factor VII:C level was observed: The initial level was 110.2 +/- 6.2 U per dl (mean +/- SEM), and the 24-hour level, 97 +/- 3.3 U per dl. Among the 72 donors, 10 were identified as cold activators; their factor VII:C level increased from 85.6 +/- 2.5 U per dl (mean +/- SEM) to 222.0 +/- 7.5 U per dl when their plasma samples were kept in plastic tubes for 24 hours at 4 degrees C. In contrast, the factor VII:C level in the plasma packs kept simultaneously in the blood bank at 4 degrees C was only 101.1 +/- 9.0 U per dl at 24 hours. Thus, it appears that plasma from donors taking oral contraceptives can be used safely even when they are not frozen immediately.

Blood Preservation↗