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L Svendsen

Publications and source records attributed to L Svendsen.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Localized nodular myositis--a variation of polymyositis].

A case of focal nodular myositis is reported. The patient was a 37-year old male with no prior medical history. He had three episodes of focal nodular myositis over a three month period, recovering completely after each attack. During the last attack there were three lesions in the left quadriceps and one in the biceps muscle of the left arm. Histologically there was severe myositis. After the last attack he has been well for 12 months without sequelae.

Adult↗
PubMed1991

Dietary calorie restriction does not affect the levels of protein elongation factors in rat livers during ageing.

Dietary calorie restriction of rats has been previously shown to increase protein synthetic rates in liver and kidney cells during ageing. Here we have compared the activity and amounts of active elongation factors EF-1 alpha and EF-2 in cell-free extracts prepared from livers isolated from male Fischer 344 rats of different ages. Although there is some age-related decline in the catalytic activity and amounts of active EF-1 alpha during ageing, no differences between freely-fed and calorie-restricted animals were observed. In the case of EF-2, the amounts of ADP-ribosylatable EF-2 neither declined during ageing nor differed between freely-fed and calorie-restricted animals. Thus differences in the protein synthetic rates in calorie-restricted and freely-fed rats are not reflected at the level of protein elongation factors, and may involve some other mechanisms of regulation.

Aging↗
PubMed1989

A new assay for the determination of factor XII in plasma using a chromogenic substrate and a selective inhibitor of plasma kallikrein.

A new chromogenic assay for factor XII in plasma was designed by the use of the soluble activator Kalliplastin, the substrate H-D-HHT-Gly-Arg-pNA and a synthetic inhibitor of plasma kallikrein (Pefabloc PK). The assay was carried out in one and the same cuvette and did not require factor XII-deficient plasma. There was a good correlation between F XII coagulant and amidolytic assays.

Benzamidines↗
PubMed1989

Precision of arterial blood gases and cutaneous oxygen saturation in healthy non-smokers.

Arterial blood from 20 healthy non-smokers (mean age 36 years) was sampled with a pre-heparinized syringe (Radiometer B129), and analysed with an automatic blood gas analyser (AVL945). Cutaneous oxygen saturation (sO2) was recorded on an ear oxymeter (Biox IIA). Mean pH +/- 2 SD was 7.392 +/- 0.072, mean arterial pCO2 +/- 2 SD was 5.15 +/- 0.90 kPa, and mean arterial pO2 +/- 2 SD was 13.68 +/- 1.90 kPa. Standard deviation for differences in pairs of analyses (SD) was, for pH 0.008, 0.20 kPa for pCO2, and 0.33 kPa for pO2. In arterial blood from 20 hypoxic patients, SD for pO2 was 0.10 kPa. Mean cutaneous sO2 +/- 2 SD was 96.7 +/- 2.2%, and mean calculated arterial sO2 +/- 2 SD was 97.6 +/- 1.0%. Mean arterial pO2 was higher than that expected from the literature.

Adult↗
PubMed1987

Characterization of the protein C activator Protac from the venom of the southern copperhead (Agkistrodon contortrix) snake.

A single chain glycopeptide with a molecular weight of approximately 37,000, an isoelectric point of 3.0 +/- 0.2 and a carbohydrate content of approximately 20% was isolated from the venom of the southern copperhead Agkistrodon contortrix contortrix. It was capable of converting zymogen protein C in plasma of man and various vertebrates into its activated form, a serine proteinase which exerts an anticoagulant effect. Conversion of the zymogen protein C into the active proteinase was demonstrated by measuring the prolongation of the activated partial thromboplastin time due to proteolytic degradation of factors Va and VIIIa by the activation product, as well as by direct measurement of the generated enzyme activity by means of a synthetic chromogenic substrate. Intravenous injection of the venom protein C activator into rabbits caused prolonged activated partial thromboplastin time. Repeated subcutaneous injections led to formation of an antibody which formed, with purified protein C activator as well as with crude A. contortrix venom, a precipitating complex devoid of protein C activator potency. As revealed by activity measurements and by immunodiffusion experiments, the venoms of various A. contortrix, A. bilineatus subspecies contain similar protein C activators.

Animals↗
PubMed1986

Protein C activators in snake venoms.

Venoms of 32 snake species were tested for protein C (PC) activating potency. As measured with the chromogenic PC substrate D-Pro-L-Pro-L-Arg-pNA, eleven venoms were able to generate amidolytic activity from purified bovine PC. In five venom solutions (Bothrops moojeni, B. pradoi, Cerastes cerastes, Vipera lebetina and V. russellii) the PC activating potency was destroyed during 10 min heating at 70 degrees C at pH 3, whereas in six venom solutions (Agkistrodon contortrix contortrix, A. c. mokasen, A. c. pictigaster, Agkistrodon piscivorus, A. p. leucostoma and A. bilineatus) the PC activator was stable under these conditions. PC activator from A. c. contortrix (Protac) was purified to homogeneity and characterized as a single chain polypeptide with a molecular weight of approx. 39-42,000 Dalton. Protac does not exert proteinase activity and is not inhibited by proteinase inhibitors; PC activation with Protac seems to be a stoichiometric reaction. The use of Protac in quantitative PC determination bears significant advantages over the use of thrombin as an activator. In rabbits, i.v. injection of Protac caused a prolonged APTT and did not provoke acute toxic reactions.

Animals↗
PubMed1983

A study of hepatic protein synthesis, three subcellular enzymes, and liver morphology in chronically ethanol fed rats.

Male Wistar rats were given ethanol chronically (20-30% of the energy as ethanol) in a nutritionally sufficient regimen. Controls received lipid as isoenergetic substitute for ethanol. Treatment lasted for 2 or 8 weeks. Hepatic protein synthesis was measured in fasted rats during a 32 min. continuous infusion of 3H-valine. After 2 weeks of treatment accumulation of hepatic protein was observed in the ethanol group, but there was no change in hepatic protein synthesis or morphology. After 8 weeks the rate of hepatic protein synthesis was decreased by 35% in the ethanol group, but there was no accumulation of protein and a slight accumulation of intracellular lipid droplets. Neither the subcellular distribution of incorporated 3H-valine, nor the activities and distributions of alcohol dehydrogenase and NADPH cytochrome c reductase were changed. Mitochrondrial cytochrome c oxidase activity was decreased in the ethanol group, and cytosolic and microsomal fractions showed higher cytochrome c oxidase activity in this group. Chronic ethanol treatment for 8 weeks had an adverse effect on general protein synthesis as well as on a specific enzyme in the liver in the absence of serious morphologic abnormalities.

Alcoholism↗
PubMed1982

Effect of calcium and synthetic peptides on fibrin polymerization.

Human fibrinogen was subjected to limited proteolytic attack by thrombin, batroxobin or Agkistrodon contortrix thrombin-like enzyme, yielding desAB-, desA- or desB-fibrin monomers, respectively. Turbidity curves demonstrated that, with all three enzymes, the polymerization process was strongly accelerated by increasing the calcium concentration from 10(-5) M to 10(-4) M. Synthetic peptide Gly-His-Arg (5 mM), an analogue of the aminoterminal sequence of fibrin beta-chain, inhibited aggregation of desB-fibrin monomers at physiological calcium concentration whereas it enhanced aggregation of desA- and desAB-fibrin monomers at calcium concentrations below 10(-4) M. On the other hand, Gly-Pro-Arg (1 mM) corresponding to the amino-terminus of fibrin alpha-chain, dramatically inhibited aggregation of both desA- and desB-fibrins, but it only moderately affected the polymerization of thrombin-induced monomers. We conclude that the observed effects of Gly-Pro-Arg and Gly-His-Arg are not due solely to their competition with fibrin amino-termini for the respective binding sites in the D-domain, but rather reflect conformational changes in fibrin monomers which affect the polymerization process.

Batroxobin↗
PubMed1982

Protein synthesis in different populations of rat hepatocytes separated according to density.

Hepatocytes were isolated from fasted rats by a two-step CA++-free/collagenase perfusion method. The cells were subjected to centrifugation under mild conditions at 12 degrees C in a linear metrizamide gradient (1.075-1.12 gm/cm3). The cells were distributed in the gradient in a bell-shaped manner. According to their position in the gradient the cells were divided in five different populations. The heaviest population was omitted from the subsequent evaluation because it contained a high proportion of dead cells. The activity of alanine aminotransferase increased with increasing cell density indicating that the lightest cell population was enriched in perivenous cells, whereas the heaviest cell population had an excess of periportal cells. Protein synthesis was more rapid in the light (perivenous) cell population than in the heavy (periportal) cell population as measured by means of incorporation of radioactively labeled valine into protein. The distribution measured in vitro indicated approximately 80% higher rates in perivenous cells. On the other hand, the synthesis and secretion of export proteins were similar in all cell populations regardless of their density. Protein degradation measured as appearance of free valine in cell media was higher in the light (perivenous) cell population than in the other populations. Thus protein metabolism seemed to be faster in the light cell population.

Alanine Transaminase↗
PubMed1982

[Simultaneous determination of zymogen activation time and zymogen level using chromogenic substrates in blood coagulation analysis].

The amidolytic activities of plasma generated by means of thromboplastin and Ca++, on the one hand, and by means of partial thromboplastin, a contact activator and Ca++, on the other hand, were determined using synthetic, chromogenic factor Xa substrates with low affinity for thrombin (CH3SO2-D-Leu-Gly-Arg-pNA and CH3SO2-D-Nleu-Gly-Arg-pNA). In this way, the activation process by splitting off the p-nitroaniline was followed. Besides the summary detection of factor Xa was obtained after addition of hirudin. During preincubation with partial thromboplastin and contact acti (Actin) in Ca++-free medium, an amidolytic activity so far unidentified was generated that renders evaluation of the activation process difficult. In the test system with partial thromboplastin, factor Xa could not be determined and the thrombin-like activity that can be inhibited by hirudin did not correspond to the amount of prothrombin present in plasma. In contrast, activation of factor X and prothrombin by thromboplastin and Ca++ could be followed and the content of the two zymogenes could be detected simultaneously. In general, under optimized reaction conditions, automated systems might be developed that would provide additional diagnostic information about determination of clotting time, on the one hand, and about quantitative determination of zymogen, on the other hand.

Calcium↗
PubMed1979

Incorporation of labelled amino acids into proteins of isolated parenchymal and nonparenchymal rat liver cells in the absence and presence of ethanol.

Parenchymal and nonparenchymal cells were isolated from perfused rat livers and incubated at 37 degrees C in the absence and presence of ethanol (50 mM). 1. Nonparenchymal cells prepared by means of centrifugation showed a higher rate of incorporation of L-[U-14C]valine into protein than nonparenchymal cells prepared by means of pronase. Cells prepared by the former method were used for further studies. 2. Protein degradation was present in suspensions of both parenchymal and nonparenchymal cells evidenced by increasing levels of branched amino acids in the intracellular and extracellular compartment during cell incubation. 3. The rate of cellular protein synthesis (corrected for precursor pool specific radioactivity) was of the same order of magnitude in nonparenchymal and parenchymal cells when expressed as nmol valine incorporated per mg protein. This rate was also close to the value found in intact liver by other workers. 4. Approximately 25% of the total radioactivity incorporated during incubation for 2 h was found in proteins released to the medium from parenchymal cells, while the corresponding figure for nonparenchymal cells was 3.5%. 5. Ethanol inhibited incorporation of labelled valine into stationary and medium proteins of parenchymal cells. No such effects were found in nonparenchymal cells. 6. Nonparenchymal cells did not metabolize ethanol while parenchymal cells did, shown by changes in lactate/pyruvate ratio and medium pH. It was concluded that nonparenchymal cells are capable of synthesizing proteins at a rate comparable to that found in parenchymal cells. Protein synthesis in parenchymal cells was inhibited by ethanol, but nonparenchymal protein synthesis was unaffected. This difference may be linked to the ability of the former cell type to metabolize ethanol.

Animals↗