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Biomedical subjects

A Oikarinen

Publications and source records attributed to A Oikarinen.

At least 145 records · Page 8Linked to original sources
PubMed1980

Effects of divalent cations on collagen biosynthesis in isolated chick embryo tendon cells.

Isolated chick embryo tendon cells were used in [14C]proline and [14C]lysine labelling experiments to investigate the effect of divalent cations on collagen biosynthesis with a special reference to prolyl hydroxylation and lysyl modifications. The following metals were studied by adding them to the incubation medium of the cells: Ca2+, Cd2+, Co2+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+ and Zn2+. Zn2+ caused a potent reductin in collagen prolyl hydroxylation with a concomitant increased cellular retention of collagenase-digestible material. These effects were detectable even at physiological concentrations. At the same concentrations of Zn2+, lysyl hydroxylation was considerably less inhibited than prolyl hydroxylation, and the extent of hydroxylysyl glycosylation was even increased. Co2+ was also an efficient inhibitor of collagen prolyl hydroxylation, but at concentrations ten times higher than those of Zn2+. In the presence of other metal ions, no or only up to 10% inhibition of prolyl hydroxylation was noted even at those concentrations at which [14C]proline incorporation into the protein was decreased. However, an increased cellular retention of collagen was detected in the presence of some metal ions. No reduction in lysyl hydroxylation was found in the presence of Ca2+ or Mg2+.

Animals↗
PubMed1980

The effects of long-term local PUVA treatment on collagen metabolism in human skin.

The effect of photochemotherapy on skin collagen metabolism was investigated in 57 patients with psoriasis. Twenty-eight patients were treated with trioxsalen baths and UVA irradiation, nine with ditranol and UVB irradiation, and 20 untreated psoriasis patients served as controls. No significant changes were found between the treated groups and the control group in urinary hydroxyproline excretion, skin hydroxyproline content, or in the activities of two enzymes catalyzing collagen biosynthesis, prolyl hydroxylase, and galactosylhydroxylysyl glucosyltransferase in the skin. When the same parameters were compared with the cumulative doses of UVA irradiation, skin prolyl hydroxylase activity slightly decreased with increasing UVA doses, whereas no changes were found in skin hydroxyproline content or galactosyl-hydroxylysyl glucosyltransferase activity. It was concluded that long-term local PUVA therapy does not significantly alter collagen metabolism in the skin.

Collagen↗
PubMed1980

Serum steroid sulphates in ichthyosis.

Serum concentrations of pregnenolone sulphate, dehydroepiandrosterone sulphate and 5-androstene-3 beta,17 beta-diol sulphate were measured by radioimmunoassays in twelve patients with various types of ichthyosis. In X-linked ichthyosis (n = 5), ichthyosis vulgaris (n = 5) and lamellar ichthyosis (n = 1), steroid sulphates were not significantly higher than in the control subjects. In one baby with ichthyosiform erythroderma and associated deafness serum 5 -androstene-3 beta,17 beta-diol sulphate concentration was about 60 fold higher (31 microgram/ml) than the mean of the control children. The other steroid sulphate levels were normal in this baby. These results indicate that it is not possible to demonstrate the steroid sulphatase deficiency in X-linked ichthyosis by determining blood steroid sulphates. The cause of the high 5-androstene-3 beta,17 beta-diol sulphate concentration in the baby with ichthyosiform erythroderma needs further evaluation.

Adolescent↗
PubMed1980

A congenital ichthyosiform syndrome with deafness and elevated serum steroid disulphate levels.

This is a report on a child with a syndrome characterized by an extensive congenital ichthyosiform eruption, neurosensory deafness and abnormally elevated serum steroid disulfates neonatally. When analysed by gas-liquid chromatography (glc) and gas chromatography-mass spectrometry (gc-ms) the following serum steroid disulfates were very high 5 days after birth: 5-androstene-3 beta,17 alpha-diol (56 micrograms/ml), 5-androstene-3 beta,17 beta-diol (25 micrograms/ml) and 5-pregnene-3 beta,20 alpha-diol (26 micrograms/ml). The values are about one hundred times higher than the reference values at this age. At the same time serum steroid monosulphate concentrations were normal. The patient had normal steroid sulfatase activity in skin biopsies, indicating that enzyme deficiency was not the reason for the high steroid disulfate concentrations. When serum steroid disulphatases were next analysed at 16 months of age they were normal. No hepatomegaly was observed but the other laboratory data support the hypothesis that the serum steroid disulphate concentrations were due to neonatal hepatography. Later, no indications of chronic liver disease were observed. These indications have not been described earlier in ichthyosiform erythrodermia and it is possible that the patient represents a new type of this rare disease.

Androstenediol↗
PubMed1979

Hormonal analysis and delayed hypersensitivity reactions in identical twins with severe acne.

Identical twins aged 17 and another pair aged 21 are described. One pair had febrile ulcerative conglobate acne; the other, cystic acne. The location of acne, the type of the lesions and the course of the disease were very similar in the two twins of each pair. The testosterone levels of the 17-year-old pair varied and their acne was in the active stage, while the 21-year-old pair had high testosterone levels and their acne was abating. The 17-year-old pair had negative Mantoux reactions and they reacted negatively to DNCB sensitization. The authors suggest that acne skin may have a certain genetically determined local factor, e.g. hormone receptor, which gives rise to acne in a certain hormonal situation.

Acne Vulgaris↗
PubMed1977

Further studies on the effect of the collagen triple-helix formation on the hydroxylation of lysine and the glycosylations of hydroxylysine in chick-embryo tendon and cartilage cells.

The hydroxylation of lysine and glycosylations of hydroxylysine were studied in isolated chick-embryo tendon and cartilage cells under conditions in which collagen triple-helix formation was either inhibited or accelerated. The former situation was obtained by incubating the tendon cells with 0.6mm-dithiothreitol, thus decreasing their proline hydroxylase activity by about 99%. After labelling with [(14)C]proline, the formation of hydroxy[(14)C]proline was found to have declined by about 95%. Since the hydroxylation of a relatively large number of proline residues is required for triple-helix formation at 37 degrees C, the pro-alpha-chains synthesized under these conditions apparently cannot form triple-helical molecules. Labelling experiments with [(14)C]lysine indicated that the degree of hydroxylation of the lysine residues in the collagen synthesized was slightly increased and the degree of the glycosylations of the hydroxylysine residues more than doubled, the largest increase being in the content of glucosylgalactosylhydroxylysine. Recovery of chick-embryo cartilage cells from temporary anoxia was used to obtain accelerated triple-helix formation. A marked decrease was found in the extent of hydroxylation of the lysine residues in the collagen synthesized under these conditions, and an even larger decrease occurred in the glycosylations of the hydroxylysine residues. The results support the previous suggestion that the triple-helix formation of the pro-alpha-chains prevents further hydroxylation of lysine residues and glycosylations of hydroxylysine residues during collagen biosynthesis.

Animals↗
PubMed1977

Effect of cortisol acetate on collagen biosynthesis and on the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in chick-embryo tendon cells.

Collagen synthesis and the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase were studied in isolated chick-embryo tendon cells after the administration of cortisol acetate to the chick embryos. When the steroid was injected 1 day before isolation of the tendon cells, collagen synthesis was decreased, even though the enzyme activities were not changed. When cortisol acetate was given as repeated injections over a period of 4 days, both collagen synthesis and the enzyme activities decreased. The hydroxylase activities decreased even more than the two collagen glycosyltransferase activities, both in isolated cells and in whole chick embryos. The amount of prolyl hydroxylase protein diminished to the same extent as the enzyme activity, indicating that cortisol acetate inhibits enzyme synthesis. The inhibitory effect of cortisol acetate on collagen synthesis and on the enzyme activities was partially reversible in 3 days. Total protein synthesis was completely restored within this time. Only massive doses of cortisol acetate inhibited collagen synthesis in vitro. Additional experiments indicated that cortisol acetate did not decrease the rate of the enzyme reactions when added directly to the enzyme incubation mixtures. The results suggest that cortisol acetate decreases collagen synthesis both by its direct effect on collagen polypeptide-chain synthesis and by decreasing the activities of enzymes involved in post-translational modifications.

Animals↗
PubMed1977

Age-related changes in human skin collagen galactosyltransferase and collagen glucosyltransferase activities.

Collagen galactosyltransferase and collagen glucosyltransferase activities were assayed in human skin specimens of about 100 mg wet weight. The assay of the glucosyltransferase activity was found to be highly specific. The assay of the galactosyltransferase activity was somewhat less specific, but there was no difference in specificity between the foetal and adult human skin samples. The activities of the two collagen glycosyltransferases in human skin extract were found to vary with age, being highest in foetal skin, and higher in the skin of young children that in that of adults. The galactosyltransferase and glucosyltransferase activities in foetal skin were respectively about 4 times and 6 times those in adult skin. The magnitudes of the changes with age in the two collagen glycosyltransferase activities were smaller than those occurring in the activities of the two other intracellular enzymes of collagen biosynthesis namely prolyl and lysyl hydroxylase. This difference suggests that the four intracellular enzyme activities of collagen biosynthesis are not regulated in an identical manner.

Adolescent↗
PubMed1977

Intracellular enzymes of collagen biosynthesis in human platelets.

Activities of four intracellular enzymes of collagen biosynthesis--prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase, and collagen glucosyltransferase--were demonstrated in human platelets, and the presence of prolyl hydroxylase protein was further demonstrated by direct radioimmunoassay. The ratio of the specific activities of the four enzymes in the four enzymes in the human platelet extract to those in human adult skin extract varied from about 0.1 to 1, the lowest relative activity being found with prolyl hydroxylase and the highest with collagen glucosyltransferase. Only a very small amount of prolyl hydroxylase protein, probably 1%, was in the form of the active enzyme tetramer. The collagen glucosyltransferase from human platelets readily glucosylated galactosylhydroxylysine in denatured collagen, but did not glucosylate native collagen. Also, native collagen did not act as an inhibitor of the glucosylation reaction. Therefore, platelet collagen glucosyltransferase cannot form either an enzyme--substrate complex or an enzyme--inhibitor complex with native collagen. The results thus argue against the theory which maintains that platelet collagen glucosyltransferase is involved in collagen--platelet adhesion.

Blood Platelets↗
PubMed1976

Effect of L-azetidine-2-carboxylic acid on glycosylations of collagen in chick-embryo tendon cells.

The glycosylations of hydroxylysine during collagen biosynthesis in isolated chick-embryo tendon cells were studied by using pulse-chase labelling experiments with [14C]-lysine. The hydroxylation of lysine and the glycosylations of hydroxylysine continued after a 5 min pulse label for up to about 10 min during the chase period. These data differ from those obtained previously in isolated chick-embryo cartilage cells, in which, after a similar 5 min pulse label, these reactions continued during the chase period for up to about 20 min. The collagen synthesized by the isolated chick-embryo tendon cells differed markedly from the type I collagen of adult tissues in its degree of hydroxylation of lysine residues and glycosylations of hydroxylysine residues. When the isolated tendon cells were incubated in the presence of L-azetidine-2-carboxylic acid, the degree of glycosylations of hydroxylysine during the first 10 min of the chase period was identical with that in cells incubated without thcarboxylic acid for at least 60 min, whereas no additional glycosylations took place in the control cells after the 10 min time-point. As a consequence, the collagen synthesized in the presence of this compound contained more carbohydrate than did the collagen synthesized by the control cells. Additional experiments indicated that azetidine-2-carboxylic acid did not increase the collagen glycosyltransferase activities in the tendon cells or the rate of glycosylation reactions when added directly to the enzyme incubation mixture. Control experiments with colchicine indicated that the delay in the rate of collagen secretion, which was observed in the presence of azetidine-2-carboxylic acid, did not in itself affect the degree of glycosylations of collagen. The results thus suggest that the increased glycosylations were due to inhibition of the collagen triple-helix formation, which is known to occur in the presence of azetidine-2-carboxylic acid.

Animals↗
PubMed1976

Hydroxylation of lysine and glycosylation of hydroxylysine during collagen biosynthesis in isolated chick-embryo cartilage cells.

Hydroxylation of lysine and glycosylation of hydroxylysine during collagen biosynthesis in isolated chick-embryo cartilage cells were studied by using continuous labelling and pulse-chase labelling experiments with [14C]lysine. Control experiments with [14C]proline indicated that in continuous labelling the hydroxylation of [14C]proline became linear with time after about 4 min and the secretion of collagen after about 35 min, as reported previously. In similar experiments with [14C]lysine the hydroxylation of [14C]lysine and the glycosylations of hydroxy[14C]lysine became linear at about 4 min, suggesting that these reactions were initiated while the polypeptide chains were growing on the ribosomes. Pulse-chase labelling experiments with [14C]lysine indicated that after a 5 min pulse-label the hydroxylation of [14C]lysine and the glycosylations of hydroxyl[14C]lysine continued during the chase period for about 20 min. The data suggest that these reactions are continued after the release of complete polypeptide chains into the cisternae of the endoplasmic reticulum, whereas the reactions are probably not continued after the formation of the triple helix and the movement of the molecules into the Golgi vacuoles.

Animals↗
PubMedDate not supplied

Radiation therapy induces tenascin expression and angiogenesis in human skin.

In analysing radiation-induced connective tissue changes, we studied tenascin expression, elastic fibres, angiogenesis and physio-mechanical properties in irradiated and contralateral healthy skin of radiotherapy-treated breast cancer patients. Skin biopsies were obtained from a radiotherapy-treated skin area and a corresponding non-treated skin area. Haematoxylin-eosin and Verhoeff stainings as well as immunohistochemical stainings for tenascin and factor VIII were performed. Epidermal and total skin thickness, together with the amount of elastic tissue calculated by computerized digital image analysis, were measured. Suction blisters were induced on both skin areas. Transepidermal water loss was analysed. Skin elasticity was also measured. Tenascin expression was found to be increased in irradiated human skin. In haematoxylin-eosin and factor VIlI-stained sections, an increase in the number of blood vessels was detected. Although skin stiffness measured by an elastometer was increased in irradiated skin, no marked difference in the elastic fibres could be found between treated and non-treated skin. The increased tenascin expression could be due to activation of cytokines as a result of irradiation. An increase in angiogenesis could be caused by an activation of angiogenetic factors by irradiation or due to direct radiation damage on blood vessel walls. Our findings suggest that the effects of irradiation tend to accumulate in the dermal parts of skin. The higher skin stiffness values measured by elastometer in irradiated skin could be due to an accumulation of dermal connective tissue as a result of irradiation.

Adult↗