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Biomedical subjects

H Prydz

Publications and source records attributed to H Prydz.

At least 163 records · Page 9Linked to original sources
PubMed1978

An immunoradiometric assay for factor III (tissue thromboplastin).

A solid-phase immunoradiometric assay for tissue thromboplastin (factor III) has been established based on its displacing effect on the binding of 125I-labelled factor III-antibodies to polyvinyl tubes coated with the purified protein component of factor III (apoprotein III). By this method circulating tissue thromboplastin can be detected in experimental animals receiving infusions of crude or purified tissue thromboplastin and in patients undergoing major orthopaedic surgery.

Animals↗
PubMed1978

The effect of nalidixic acid, rifampicin and chloramphenicol on the synthesis of phospholipase C in Bacillus cereus.

The effect of nalidixic acid, rifampicin and chloramphenicol on the synthesis of phospholipase C (EC 3.1.4.3) has been studied in washed Bacillus cereus cells resuspended in nutrient broth. In the absence of inhibitors, the synthesis showed a biphasic pattern. No synthesis of release of enzyme was found in the presence of chloramphenicol. When rifampicin was added, phospholipase C synthesis continued for 10-15 min. Nalidixic acid, at concentrations which inhibited DNA synthesis completely, permitted the synthesis of phospholipase C at the same rate and for a similar length of time as rifampicin.

Bacillus cereus↗
PubMed1977

DNA replication intermediates in whole HeLa cells and isolated nuclei.

Replicative intermediates have been studied in intact HeLa cells and in nuclei isolated from such cells. In whole cells the smallest DNA (primary DNA pieces) observed after pulse labelling with [3H]thymidine were 90-160 nucleotides long, and the size of the molecules in this class of DNA did not increase with increasing pulse length. Some increase in size was, however, observed when cells were pulse labelled at 25 degrees C instead of 37 degrees C. Chase experiments using nuclei from pulse-labelled cells suggested that the primary DNA pieces could be chased rapidly into DNA of high molecular weight (30-70 S, corresponding to a molecular weight of 0.7 - 10(7)-6.4-10(7)). Longer chases showed that the label eventually accumulated in DNA with s values greater than 150 S. In isolated nuclei the primary DNA pieces after a 1 min pulse at 37 degrees C were approximately 200 nucleotides long. Primary pieces of this size were also rapidly chased into the 30-70 S region. However, during longer pulses in vitro a fraction of the primary DNA pieces grew beyond their normal size to reach a size of up to 2000-3000 nucleotides before being attached to the 30-70 S molecules.

Cell Nucleus↗
PubMed1977

The N-terminal activation fragment of bovine prothrombin. Immunological studies leading to a one step purification.

Some immunological studies on prothrombin fragment 1 from bovine prothrombin and its warfarin-induced precursor acarboxyprothrombin are reported. Based on the results, a rapid and simple immunoadsorption method for the isolation of prothrombin fragment 1 in good yield has been established. The method exploits the conformational change induced in the fragment by removal of Ca2+. The principle may be applicable to other gamma-carboxyglutamyl-containing proteins or fragments therof.

Apoproteins↗
PubMed1977

The effect of phospholipase C on platelet factor 3 in human blood platelets.

Intact human platelets isolated by gel filtration have been treated with purified phospholipase C. The effect of the enzyme on available and total platelet factor 3 has been tested. The available procoagulant platelet factor 3 was very low. A further small reduction was observed after incubation with phospholipase C when the enzyme was washed away before testing. External attack on platelets by phospholipase C led to a marked inactivation of total platelet factor 3.

Blood Coagulation Factors↗
PubMed1977

Localization of tissue thromboplastin in the human brain.

Monospecific antisera against the purified protein component of tissue thromboplastin (apoprotein-III) from human brain have been raised in goats and rabbits. The antisera neutralized tissue thromboplastin prepared from brain, thyroid gland and pulmonary tissue, indicating that apoproteins in the various preparations cross-reacted immunologically and therefore were similar or identical. Comparison of the activities of tissue thromboplastin preparations from 34 different areas of the brain demonstrated a characteristic distribution pattern and a wide range of activities. White and grey matter from the same areas had similar activities. Bulbus and tractus olfactorius, medulla oblongata, corpus pineale, hippocampus and hypothalamus contained 160-270% of the average activity, whereas cerebellum globus pallidus, nucleus ruber and substantia nigra contained 30-60%. The distinct distribution pattern was unrelated to tissue vascularization, and may suggest that apoprotein-III could serve other functions, apart from the coagulation of blood. The predominance in phylogenetically older brain regions would suggest that it represents a primitive or fundamental feature.

Animals↗
PubMed1977

Inhibition of the synthesis of phospholipase C in Bacillus cereus by a component of the growth medium.

A low molecular weight compound, probably of peptide nature, present in the Beef Heart Extract component of the growth medium, inhibits post-transcriptionally the biosynthesis of phospholipase C by a strain of Bacillus cereus. The compound also prevents the increase of proteolytic activity in the growth medium, thus suggesting that the synthesis of another enzyme, an extracellular protease, is also inhibited, and that the inhibitory compound may therefore have a more general effect on exoenzyme synthesis in this strain of Bacillus cereus.

Bacillus cereus↗
PubMed1976

The influence of ethanol feeding on the activities of factors II, VII, VIII, IX and X in rats.

The effect of chronic administration of ethanol to rats in a controlled regimen upon the activities of the coagulation factors II, VII, VIII, IX and X has been studied. No significant differences were found for factor II, IX and X between the ethanol-treated rats and the control group given an isocaloric diet with carbohydrate replacing ethanol. Factor VII activity was somewhat higher and factor VIII activity decreased significantly in the experimental group when ethanol treatment was combined with an approximately two-fold increase in dietary polyunsaturated fatty acid.

Animals↗
PubMed1976

The effect of phospholipase C on DNA synthesis, morphology and phospholipid content of isolated HeLa cell nuclei.

Isolated HeLa cell nuclei have been treated with purified phospholipase C (Bacillus cereus) and sphingomyelinase (Staphylococcus aureus). The phospholipids of untreated nuclei consisted of about 67% phosphatidylcholine, 23% phosphatidylethanolamine, 7% sphingomyelin, 2% phosphatidylserine and 1% phosphatidylinositol. Phospholipase C degraded 80-90% of the total phospholipids of the nuclei. Such nuclei seemed ultrastructurally intact, and had an average diameter and a protein loss during incubation which were not significantly different from those of controls. Their rate of DNA synthesis was only slightly reduced after treatment with phospholipase C alone and slightly more reduced when phospholipase C was used in combination with sphingomyelinase. This suggests that the polar head-groups of the nuclear phospholipids are of very limited importance in DNA synthesis. Since it has been reported that phospholipase C treatment releases nascent DNA from a membrane complex, the absence of a concommitant reduction in DNA synthesis may suggest that this complex is not necessary for the replication of DNA. Phospholipase C did not significantly influence the stability of the DNA product and gave only a slight inhibition of cytosol and nuclear DNA polymerases when tested with exogenous template.

Cell Nucleus↗
PubMed1976

Effect of 1-beta-D-arabinofuranosylcytosine triphosphate on DNA synthesis in isolated HeLa cell nuclei.

1-beta-D-Arabinofuranosylcytosine 5'-triphosphate (ara-CTP) was found to be a competitive inhibitor of DNA synthesis in nuclei isolated from synchronized S-phase HeLa S3 cells. The inhibition was reversed by dCTP. The main inhibitory effect was to reduce the rate of elongation of the primary DNA pieces from ara-CTP-treated nuclei after a 60-s pulse was about 115-120 nucleotides vs. 215-220 in control nuclei. A reduction in the frequency of initiation of primary DNA pieces probably also occurred. A slight inhibition of the transfer of labeled material from the primary pieces into high-molecular weight DNA was noted and probably arose from the fact that the reduced rate of growth of the primary pieces caused the critical size for ligation to be reached later. Synchronized HeLa S3 cells in suspension were treated with 1-beta-D-arabinofuranosylcytosine for 2 h in S-phase to give a 99% inhibition of DNA synthesis prior to isolation of nuclei. Neither the rate nor the extent of [3H]TTP incorporation into DNA decreased when such nuclei were incubated in the absence of ara-CTP, but the rate of ligation of primary pieces was reduced.

Cell Division↗
PubMed1976

The effect of antithrombin III on the activity of the coagulation factors VII, IX and X.

Antithrombin III, purified to homogeneity according to polyacrylamide gel disc electrophoresis and immunoelectrophoresis, inhibited the activity of purified factor IXa and Xa, whereas factor VII was not inhibited either in the active or in the native form. Antithrombin III is the single most important inhibitor of factor Xa in plasma. Factor Xa does not, however, reduce the activity of antithrombin III against thrombin.

Antithrombins↗
PubMed1976

The effect of intravenous injection of purified human tissue thromboplastin in rats.

As a background for the development and testing of phospholipase C in the therapy of post-traumatic and post-surgical intravascular coagulation, highly purified tissue thromboplastin was injected i.v. into rats. The levels of factor V, VII, VIII and blood platelets and the activity of the intrinsic coagulation pathway in general (the cephalin test) were followed. Histological examination of pulmonary, kidney and liver tissue was carried. The dose-response was highly dependent on the injection rate. A marked activation of factor VII and a fall in the activities of factors V and VIII as well as in thrombocyte counts were observed. Very few or no thrombi were seen beyond the pulmonary circulation. The main changes (fibrin-containing thrombi and platelet aggregates) were observed in the lungs during the first 15 min after injection. Atter 15 min virtually no thrombi or platelet aggregates could be detected. The effect of tissue thromboplastin was counteracted by large doses of antithrombin III.

Animals↗