Biomedical subjects

L R Pedersen

Publications and source records attributed to L R Pedersen.

9 recordsLinked to original sources

PubMed1990

Collagen distribution in developing experimentally induced granulation tissue. A morphometric study.

Viscose cellulose sponges were implanted subcutaneously on the back of full-grown Sprague-Dawley rats. Seven, 14, 21, 28, 42, 60 and 90 days after implantation, groups of 12 animals decapitated and the sponges were removed and processed for light microscopy. Five microns sections were stained with Picro-Sirius Red. Morphometry was performed on the zone of ingrowth and the collagen. The intersectional variation in the morphometrically determined collagen density within the sponges was below 20%. The hydroxyproline content was determined biochemically in 5 microns sections of sponges implanted for 14, 42, 60 and 90 days. A positive correlation (rho = 0.79, p less than 0.0001) was observed between the biochemically and morphometrically determined collagen contents. The morphometric determinations showed a steady increase in the granulation tissue ingrowth. At day 60 the ingrowth was complete. There was an increasing collagen density from days 7 and 14 through days 21 and 28, followed by a nearly steady state up to day 90 and a significantly higher collagen density peripherally than centrally in the day 42 sponges. The study has shown that morphometric collagen determination at light microscopical level using Sirius Red-stained sections may add quantitative data describing the dynamic changes in collagen content and distribution within developing granulation tissue.

Animals↗

PubMed1990

Gallbladder stones classified by chemical analysis of cholesterol content. Frederiksberg, 1987-1988.

Gallstones from 80 cholecystectomies and 81 autopsies were chemically analysed and showed a trend of decreasing cholesterol content with increasing age (p = 0.00009). The frequency of cholesterol stones (cholesterol content greater than 70%) was higher in operated women (81%) than in operated men (33%) (p = 0.0006) and in the total autopsy material (42%). The study supports the theory that the predominance of gallstone disease in women is an effect of the preponderance of cholesterol stones. The accuracy of estimates of cholesterol content of gallstones from the appearance of the cut surface was low. When the chemical analysis was used as a key, only one in three was correct. There was a tendency to underestimate cholesterol content.

Age Factors↗

PubMed1989

Lipid metabolism and coagulation of two contraceptives: correlation to serum concentrations of levonorgestrel and gestodene.

The effects of two triphasic oral contraceptives containing the same amount of ethinylestradiol (EE) in combination with levonorgestrel (LNG) or gestodene (GES), respectively, on lipid metabolism and coagulation were studied. Serum concentrations of GES and LNG were determined at the same time. Thirty-three healthy women were randomized into two groups receiving either of the preparations. Before treatment and in the 3rd and the 6th cycle, blood samples were drawn in the morning while subjects were still in bed to obtain basal conditions. HDL2-cholesterol decreased in the LNG group but was unchanged in the GES group, whereas apolipoprotein A1 increased in the GES but not in the LNG group. Antithrombin III decreased in the GES group but was unchanged in the LNG-treated women. Factor VII increased in both groups, but more in the GES group. It is concluded that GES has a positive influence on lipid metabolism, and has a slightly negative influence on coagulation but the latter is more likely to be without clinical relevance. The positive influence of GES compared to LNG on lipids is probably due to its lower androgenicity and not to differences in bioavailability.

Adult↗

PubMed1988

Collagen type IV and procollagen type III during granulation tissue formation: a serological, biochemical, immunohistochemical and morphometrical study on the viscose cellulose sponge rat model.

The serum concentrations of collagen type IV,7S, collagen type IV,nc1, and aminoterminal type III procollagen peptide immunoreactive components were measured by means of specific radioimmunoassays during development of granulation tissue in rats. The results were compared with tissue deposition of basement membranes and interstitial collagens in the granulation as measured morphometrically. A parallel sequential pattern in tissue deposition of collagen types III and IV, and serum increase of collagen types III- and IV-related fragments, was observed. Serum collagen type IV was less sensitive as a marker for development of granulation tissue than the serum procollagen type III N-peptide. This was in accordance with a low collagen type IV/interstitial collagen ratio in the granulation tissue. However, a cross-sectional study showed that serum collagens types IV,7S and IV,nc1 may be useful as early quantitative indicators of granulation tissue formation. Simultaneously, measurement of collagen type IV- and procollagen type III N-peptide-related antigens in serum provides a differentiated reflection of the dynamic matrix processes in developing granulation tissue.

Animals↗

PubMed1988

Serum aminoterminal type III procollagen peptide. Relation to biosynthesis of collagen type III in experimentally induced granulation tissue in rats.

Serum aminoterminal type III procollagen peptide was measured in rats during the development of granulation tissue induced by subcutaneous implantation of viscose cellulose sponges. Active collagen type III synthesis in granulation tissue during the first three weeks was accompanied by an increase in serum propeptide level. A positive correlation was observed between the increase in serum propeptide level on the one hand and the increase in granulation tissue collagen type III content and the in vitro formation of tissue 3H-hydroxyproline on the other hand. In some animals the serum propeptide level remained low, despite biochemical signs of collagen synthesis, indicating variations in the release into serum and/or the metabolism of circulating propeptide. The increase in propeptide antigen concentration was mainly due to an elevated content of material with molecular weight equal to or twice that of the propeptide. A minor fraction of the propeptide remained attached to the interstitial collagen fibres in the granulation tissue. The correlation between the serum propeptide level and the biosynthesis of collagen at the site of the focal fibroproliferative process suggests that the serum propeptide level may be a valuable indicator of fibrogenesis and thereby of disease activity in fibrotic conditions.

Animals↗

PubMed1987

Serum lipids in hyper- and hypothyroidism before and after treatment.

Total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), triglycerides (TG) and apoprotein A (Apo A) were determined in serum from 21 hyperthyroid patients and 11 hypothyroid patients before and after treatment to euthyroid state. The above-mentioned components were also determined in a reference population. In the hyperthyroid group the concentration of total cholesterol and low density lipoprotein-cholesterol increased significantly upon treatment. High density lipoprotein also increased except for 9 patients also receiving propranolol. The ratio between high density lipoprotein-cholesterol and total cholesterol decreased in the patients receiving propranolol. In the hypothyroid group the values after treatment decreased significantly for cholesterol, high density lipoprotein-cholesterol and low density lipoprotein-cholesterol. The ratio between high density lipoprotein-cholesterol and total cholesterol was unchanged.

Adult↗

PubMed1985

Receptor-mediated endocytosis of a ricin-colloidal gold conjugate in vero cells. Intracellular routing to vacuolar and tubulo-vesicular portions of the endosomal system.

We have prepared a conjugate (Ri-Au) of the toxic plant protein ricin and colloidal gold (particle size 5 nm) and used it for internalization studies in monolayer cultures of Vero cells. The Ri-Au conjugate was very stable, with only little release of ricin ([125I]Ri) from the gold particles within a pH range of 4.5-8.0. Within 2 h at 37 degrees C, only very little intracellular degradation of the ricin preparation ([125I]Ri-Au) occurred. The cells bound the same proportion of native ricin ([125I]Ri) and Ri-Au from the medium, and the kinetics of toxicity (decrease in cellular incorporation of [3H]leucine) of [125I]Ri and [125I]Ri-Au were also comparable. At 4 degrees C, the cell-surface binding of Ri-Au was continuous and distinct, as revealed by electron microscopy. This binding was specific, since almost no Ri-Au surface binding occurred at 4 degrees C in the presence of 0.1 M lactose or 1 mg/ml native (unlabelled) ricin. Within the first 30 min of warming prelabelled cells to 37 degrees C, the amount of surface-associated Ri-Au decreased considerably (from 150 to 60 gold particles per micron cell surface in 40 nm sections). Coated pits and vesicles were involved in the internalization of Ri-Au, and within 5-30 min at 37 degrees C Ri-Au had been delivered to vacuolar and tubulo-vesicular portions of the endosomal system, and later also to lysosomes. Analysis of very thin (ca 20 nm) serial sections revealed that most of the tubulo-vesicular elements were separate structures not connected to the membrane of the vacuolar portion. Data here presented indicate that our ricin conjugate, like many "physiological' ligands and viruses, is internalized by receptor-mediated endocytosis via the coated pit-endosomal pathway.

Animals↗

PubMed1979

Determination of total 3 alpha-hydroxy bile acids in serum.

The usual techniques for determination to total 3 alpha-hydroxy bile acids in serum involving liquid-solid extraction of the bile acids with the adsorbent XAD-2 and fluorimetric measurement of NADH generated from the reaction with a NAD-linked 3 alpha-hydroxysteroid dehydrogenase are evaluated and improved. The influence of different types of enzyme preparations on the results is examined. The results with the improved technique are compared to the results obtained with another method, avoiding extraction of the bile acids before the enzymatic reaction which is followed by fluorimetric measurement of resorufin, produced by transfer of the hydrogen of the generated NADH by diaphorase to resazurin. No significant difference between the results with the two types of methods was found. The concentration of total 3 alpha-hydroxy bile acids in serum of 46 fasting 'healthy' individuals aged 17 to 82 years is estimated. 30 were females, of whom 10 were taking estrogen-containing oral contraceptives, and 16 were males. Mean +/- standard deviation in all the females was 3.0 +/- 1.1 micromol/l, and in the males 4.0 +/- 1.9 micromol/l. There was no significant difference between any of the groups.

3-Hydroxysteroid Dehydrogenases↗

PubMed1977

Criteria for selection of patients for medical treatment (chenodeoxycholic acid therapy) of gallstones.

With the introduction of medical treatment (chenodeoxycholic acid therapy) of cholesterol gallstones, the prediction of the gallstone type, cholesterol--non-cholesterol stones, (i.e. cholesterol predominating or not), has become important. In 24 consecutive patients admitted for surgery because of gallstones, the value of various criteria for differentiation between the two types of stones was assessed. It is concluded that the combined requirements of radiolucency of the stones and a cholesterol saturation index in duodenal bile above 1.00 constitutes a fairly reliable method for selection of patients for dissolution therapy with chenodeoxycholic acid.

Adult↗