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Biomedical subjects

M Karpatkin

Publications and source records attributed to M Karpatkin.

49 records · Page 3Linked to original sources
PubMed1979

Humoral factor that specifically regulates prothrombin (factor II) levels (coagulopoietin-II).

Prothrombin (Factor II) was decreased in rabbits by injection of a goat antiserum to prothrombin. When plasma from these rabbits was injected into normal animals, circulating prothrombin increased in the recipients, suggesting transfer of a humoral regulating factor ("coagulopoietin-II"). This coagulopoietin-II resisted boiling for 20 min. On Sephadex G-50 gel filtration, it remained in the retained volume, suggesting a molecular weight of less than 30,000. In an in vitro liver system, prothrombin increased in the incubation medium in the presence of coagulopoietin-II.

Animals↗
PubMed1979

Humoral factor that specifically regulates factor X levels in rabbits (coagulopoietin-X).

A heat-stable humoral substance (coagulopoietin-X) is present in rabbits partially depleted of Factor X, which is capable of raising Factor X levels when injected into recipient rabbits. Rabbits were partially depleted of Factor X by slow infusion of a globulin fraction of goat anti-rabbit Factor X antibody. This resulted in the reduction of Factor X to 40--50% of normal at 1 h and 60--70% of normal at 6 h. No effect was noted on levels of Factors II, V, or VII. Plasma from these animals, when injected into 10 recipients, specifically raised Factor X levels when measured by four different assay: one-stage assay with bovine VII- and X-deficient plasma and Russell's viper venom; one-stage assay with human X-deficient plasma and thromboplastin; chromogenic substrate assay with Russell's viper venom; and an immunologic assay (Laurell technique). No rise was noted in two control experiments in which normal plasma was injected into recipient rabbits from 2 rabbits injected with a globulin fraction of normal goat serum, nor in 12 rabbits injected with plasma from normal rabbits, nor in 5 rabbits injected with boiled plasma from normal rabbits. The rise in biologic activity of 120--150% of base line was significantly greater than the rise in immunologic activity of 114--117% of base line (P less than 0.05) on 3 different days, suggesting the production of a molecule with greater specific activity rather than increased protein synthesis.

Animals↗
PubMed1978

Antibody to varicella-zoster virus after passive immunization against chickenpox.

Antibody titers to varicella-zoster virus were measured in varicella-susceptible immunocompromised children 48 h after they received either one of two lots of zoster immune globulin (ZIG) or a selected lot of immune serum globulin (ISG). Globulin was given to modify varicella in these children after exposure to varicella or zoster. Indirect immunofluorescence antibody titers (FAMA) of children after receipt of globulin ranged from less than 1:2 to 1:32. Geometric mean FAMA titers were highest after 1.2 ml of ISG per kg (FAMA titer 1:128) and 0.16 ml of ZIG lot A per kg (FAMA titer 1:1,024). Selected batches of ISG titering 1:128 or greater by FAMA, at a dose of 1.2 ml/kg, may be used to attempt to modify varicella in susceptible high-risk individuals when ZIG is not available.

Antibodies, Viral↗
PubMed1978

Identification of a coagulopoietin for prothrombin.

A coagulopoietin specific for factor II has been demonstrated in the rabbit, and termed 'coagulopoietin-II'. A goat antiserum was used to lower the factor II level in a rabbit. When plasma from this rabbit was then injected into other rabbits, factor II rose in the recipients without increase in other coagulation factors measured (V, VII, and X). The coagulopoietin is stable to boiling for 30 minutes, and appear to have a molecular weight of less than 30,000.

Animals↗
PubMed1977

The platelet factor 3 immunoinjury technique re-evaluated. Development of a rapid test for antiplatelet antibody. Detection in various clinical disorders, including immunologic drug-induced and neonatal thrombocytopenias.

A modified version of the platelet factor 3 immunoinjury technique for the detection of antiplatelet antibody is described in detail; heat-inactivated sera and frozen platelets are employed. The modification allows the results of the test to be available within 4 to 5 hours after drawing the blood sample, in contrast to the 3 days required in the original method. The technical work involved is significantly reduced. The reproducibility of the technique is improved. Results obtained with the two tests correlate well. Data accumulated in 458 cases of clinical disorders associated with antiplatelet antibody are reported. Drug-dependent antiplatelet antibody was demonstrated in 26 cases of thrombocytopenia associated with 19 different drugs. Data are also presented for 23 cases of neonatal thrombocytopenia.

Autoantibodies↗
PubMed1976

Evidence suggesting the regulation of a coagulation factor levels in rabbits by a transferable plasma agent.

New Zealand white rabbits were given 30 ml of goat serum intravenously. This procedure resulted in an immediate decrease in platelet count, fibrinogen, and levels of coagulation factors II, V, VII, and X, due to consumption coagulopathy. These factors returned toward baseline levels approximately 12 hr after the injection. Plasma from rabbits who had received goat serum 48 hr previously (donor rabbits) was injected into recipient rabbits. This procedure resulted in a slight rise in the level of coagulation factor II (range, 20%-30%) and a significant rise in factors V (35%-75%), VII (35%-235%), and X (35%-75%) in the recipients. When plasma from control donor rabbits who had not received goat serum was injected into recipients, there was no change in these coagulation factors. It is postulated that the reduction in coagulation factor levels in donor rabbits induces a "coagulopoietin" for each factor or one "coagulopoietin" for all factors which stimulates increased synthesis and/or release of these factors in recipient rabbits.

Animals↗