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T L Janson

Publications and source records attributed to T L Janson.

9 recordsLinked to original sources
PubMed1987

A simple method for determination of the factor VII-phospholipid complex using Normotest.

We report here a highly significant positive correlation observed when the factor VII-phospholipid complex (the phospholipase-C sensitive component of factor VII) in plasma was tested in a specific factor VII system and in Normotest (p less than 0.0001). The Normotest system, which is sensitive to variations in coagulation activity within the normal range, was not influenced by phospholipase C when the enzyme was added immediately before the start of the coagulation assay. Normotest is well suited for determination of the factor VII-phospholipid complex in plasma.

Animals↗
PubMed1984

Species specificity of tissue thromboplastin.

The species specificity of thromboplastin (tissue factor) is an important fact to take into consideration when clotting assays or experiments are planned. We have (re)investigated all possible combinations of thromboplastin and plasma from several of the most commonly used species of experimental animals.

Animals↗
PubMed1983

Intravenous injections of tissue thromboplastin and phospholipase C in rabbits.

Previous experiments (Gollub et al. [10]. Giercksky et al.) have shown that phospholipase C (PLC) has a protective effect on rats and rabbits receiving thromboplastin infusions. As a step towards the possible use of PLC in humans, we have investigated further the use of PLC in rabbits. Infusions of human or rabbit thromboplastin caused a rapid fall in factors V and VIII. LD50 for our standard human thromboplastin preparation was estimated to be 1.5--1.8 ml/kg. Highly purified PLC was given as an intravenous bolus immediately before thromboplastin. No improvement of survival and only a slight difference in factors V and VIII were observed, in contrast to earlier observations in the rat. This may in part be due to differences in the susceptibility to PLC of the thromboplastins used. PLC was also more toxic in rabbits than in rats.

Animals↗
PubMed1982

In vitro effect of phospholipase C from Bacillus cereus on tissue thromboplastin from different species.

Purified phospholipase C from Bacillus cereus caused a significant loss in the procoagulant activity of thromboplastin preparations from man, rabbit, sheep, cow, rat and mouse. However, marked differences were observed with respect to the degree of inactivation. Rat, mouse, bovine and one type of rabbit preparations (prepared from acetone powdered brain) were markedly more sensitive to attack by phospholipase C than were preparations of human, sheep and standard rabbit preparations. The relative amounts of the individual phospholipids in thromboplastin preparations showed only minor variations among the species. The effect of phospholipase C on each of these phospholipids in the various thromboplastin preparations showed some significant differences.

Animals↗
PubMed1980

Electron microscopy of lanthanum in plasma.

Aqueous solutions of lanthanum nitrate may be used as electron microscopic tracers in vivo to study vascular permeability in the experimental animal. However, with this technique the size of the tracer articles is not known. To gain information about the tracer size, we injected lanthanum nitrate into the blood circulation of living rabbits. The plasma obtained from such animals 30 min later, was studied with the electron microscope. The plasma contained an electron-dense material, readily visible in the electron microscope. A precipitate obtained after centrifugation of the whole blood to separate the cells, also contained the tracer. Lanthanum was found in large amounts in the fibrin clot obtained after treating the plasma with thrombin. The tracer was not detected in the "serum" (i.e. thrombin-treated plasma). The study indicates that ionic lanthanum injected into the blood circulation of living rabbits, is to a great extent bound to fibrinogen, and that the smallest possible size of the tracer is that of the fibrinogen molecule (m.w. 330,000). Larger particles are present as well.

Animals↗
PubMed1975

Biological and immunological activity of prothrombin in rough and smooth microsomes isolated from rat liver.

1. The presence of biological and immunological activity of prothrombin in sonicates from rough and smooth microsomes has been investigated. 2. Biological activity of prothrombin was detected in both the rough and smooth microsomal fraction. The specific and the total activity of prothrombin in the sonicates from smooth microsomes were 3-4-fold higher than in the corresponding fraction from rough microsomes. 3. Prothrombin could be identified in both microsomal fractions by double immunodiffusion. 4. The presence of a macromolecular inhibitor of blood coagulation in the microsomes is reported.

Animals↗