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Biomedical subjects

R Penttinen

Publications and source records attributed to R Penttinen.

At least 55 records · Page 3Linked to original sources
PubMed1982

Desmosines in aneurysms of the ascending aorta (annulo-aortic ectasia).

Amino acid chromatography was used for determination of the elastin-specific amino acids desmosine and isodesmosine in acid hydrolyzates of intima-medial samples taken intraoperatively from aneurysms of human ascending aorta. Elastin concentration of the specimens was also estimated by hot alkali extraction followed by nitrogen determination of the extracted material and the insoluble residue. All patients studied had annulo-aortic ectasia i.e., dilatation of the aortic annulus and the ascending aorta. Two patients with the Marfan syndrome had low aortic elastin concentration determined by both methods. A third Marfan syndrome patient, youngest of the three, also had a slightly reduced concentration of elastin in the aorta. Aortic samples were studied from five patients who did not have the classical Marfan syndrome. Two patients of those five had decreased aortic elastin concentration. The change in elastin concentration was accompanied by high hydroxyproline/proline or hydroxylysine/lysine ratios which indicates that the proteins of the aneurysmatic aortic wall contained more collagen than the proteins of the control aortic wall. These findings point to a change in the structure or metabolism of elastin in the aortic wall in the Marfan syndrome and at least in some other patients with annulo-aortic ectasia.

Adolescent↗
PubMed1982

A method for the hyaluronic acid synthetase assay in human skin.

A method for the determination of hyaluronic acid synthetase activity of human skin is described. Skin samples were crush-homogenized, and incubated with UDP-14C-glucuronic acid and UDP-N-acetylglucosamine in Tris-HCl-buffer containing MgCl2. After papain digestion of the samples, the 14C-labeled hyaluronic acid was separated in Sephadex G 50 chromatography. The radioactivity incorporated into hyaluronic acid was an expression of the activity of hyaluronic acid synthetase. This activity was found to be increased in skin biopsies obtained from psoriatic lesions and decreased after local treatment with potent corticoids.

Adrenal Cortex Hormones↗
PubMed1982

Synthesis of underpolymerized hyaluronic acid by fibroblasts cultured from rheumatoid and non-rheumatoid synovitis.

Fibroblast cultures were started from synovial tissue of normal controls and patients with seronegative and seropositive rheumatoid arthritis, juvenile rheumatoid arthritis and chronic non-rheumatoid synovitis. Glycosaminoglycan synthesis of the cultures was studied by metabolic labeling with 3H-glucosamine. Molecular weight of hyaluronic acid produced and secreted into culture medium by these fibroblast strains was studied by gel filtration in a Sepharose 2 B column. All fibroblast strains from joints with active inflammation produced hyaluronate with decreased molecular weight. The synthesis of underpolymerized hyaluronate thus appears to be a property of activated synovial fibroblasts common to rheumatoid and non-rheumatoid inflammation.

Adolescent↗
PubMed1982

Metabolism of collagen in aspartylglycosaminuria: decreased synthesis by cultured fibroblasts.

Fibroblasts from patients with aspartylglycosaminuria (AGU) and from age-matched healthy controls were studied in culture. The rate of synthesis of collagenous proteins was lower in AGU fibroblasts than in control cells despite the fact that the growth rates and growth patterns were similar. Qualitative differences in culture media proteins between AGU and control cultures were not revealed by gradient gel electrophoresis or by CM-cellulose chromatography after pepsin treatment. DEAE-cellulose chromatography of AGU culture media components showed that they contained more [3H]glucosamine-labelled glycoproteins than the control cultures. Decreased collagen synthesis may explain the connective tissue symptoms (e.g. skeletal deformations and susceptibility to hernias) frequently present in AGU patients. Products from the incomplete intracellular degradation of glycoproteins can interfere with collagen synthesis in AGU. Aspartylglycosaminuria might thus provide a model for studying the regulation of collagen synthesis.

Acetylglucosamine↗
PubMed1981

Collagen synthesis in cells cultured from v. Recklinghausen's neurofibromatosis.

Subcutaneous tumors of a patient with v. Recklinghausen's neurofibromatosis contained about 31% collagen calculated on the basis of lipid-free dry weight. Slices of the tumors synthesized collagen at a rate (4.7-8.5% from total protein) which was higher than that of the skin slices (2.8-5.9%). Neurofibromatosis cells were cultured from tumors of two patients. They synthesized relatively much more collagen than cultures of skin fibroblasts of the same patient or of healthy age-matched control persons. The second patient's cultures were studied in detail. The cell densities of these cultures were higher and expressed more variation than the densities of control skin fibroblasts. Ion exchange cellulose chromatograms, SDS-polyacrylamide gel electrophoresis and 3-hydroxyproline analysis of the radioactive proteins made by the cultures indicate that most of the collagenous proteins resembled type I collagen. High proliferative capacity and high collagen synthesis of selected neurofibromatosis cells explains the growth of solid tumors.

Cells, Cultured↗
PubMed1981

Biochemical changes in bone grafts stabilized with rigid plates. I. Cancellous grafts.

The effect of rigid plate fixation on the chemical composition of cancellous interposition grafts was studied in rabbit-fibular bones. The concentrations of hexosamines and, to a lesser degree, of hydroxyproline and nitrogen, were high in the graft for the first 6 weeks, decreased from weeks 6 to 12, but remained higher than the corresponding values for the controls throughout the experiment (52 weeks). The ratio of hexosamines to hydroxyproline was highest for the graft at 3 weeks, indicating formation of cartilage and osteoid. The initially low calcium concentration of the graft increased by 35 per cent from weeks 1 to 6, decreased from weeks 6 to 12, and remained below normal thereafter in comparison with corresponding values for the cortical host bone. The ratio of calcium to hydroxyproline increased throughout the experiment, reflecting maturation of the graft to lamellar bone. Thus, biochemically the early incorporation of rigidly fixed cancellous interposition grafts resembles the healing of unimmobilized fractures by callus formation.

Animals↗
PubMed1981

Biochemical changes in bone grafts stabilized with rigid plates. II. Cortical grafts.

The effect of rigid plate fixation on the chemical composition of cortical interposition grafts were studied in rabbit tibio-fibular bones. The concentration of hexosamines increased both in the graft and in the host bone during the first 6 weeks, but thereafter decreased. The concentrations of hydroxyproline and nitrogen increased throughout the experiment. The ratio of hexosamines to hydroxyproline increased in the graft for the first 6 weeks, indicating formation of immature osteoid and bone during this period, but thereafter decreased. The calcium concentration of the graft decreased significantly during the first 12 weeks and remained below normal (-10 to -19 per cent). The mineralization of the graft, assessed by the ratio of calcium to hydroxyproline, decreased continually. The results suggest that cortical bone grafts stabilized with rigid plates heal with only slight chemical signs of callus formation. The demineralization of the graft reflects the porotic changes that take place under the plate.

Animals↗
PubMed1981

Collagen synthesis in cultured mesothelial cells. Response to silica.

Mesothelial cells were isolated from the peritoneal surface of rats using trypsinization. The cells were polygonal-shaped and proliferated rapidly forming confluent cultures. Application of colloidal silica to mesothelial cell cultures in doses known to induce peritoneal adhesion disease was injurious to the cells and reduced their synthesis of total proteins and collagen. This effect was dose dependent. Media from silica-treated mesothelial cells and granulation tissue fibroblasts were applied to similar but non-treated mesothelial cell and granulation tissue fibroblast cultures. Media from SiO2-treated mesothelial cells increased collagen synthesis markedly both in the mesothelial cell and fibroblast cultures compared with the control cultures as estimated from the incorporation of radioactive proline into hydroxy-proline-containing proteins. However, no stimulation of collagen synthesis was induced by media from the SiO2-treated granulation tissue fibroblasts. Similar effects are known to be induced in fibroblast cultured by media from silica-treated peritoneal macrophage cultures. The alkaline ribonuclease activities of the media were decreased in silica-treated mesothelial cell and macrophage cultures but not in the media of fibroblast cultures. These results suggest that mesothelial cells, like macrophages, can interfere with the protein synthesis of fibroblasts and thus contribute to the regeneration of mesothelium after injury and to the formation of adhesions.

Animals↗
PubMed1981

Fibronectin in early phases of wound healing in children.

Fibronectin, an adhesive glycoprotein, was demonstrated with the Cellstic device in healing wounds of 13 children after routine surgery. An indirect immunofluorescent method was adapted to cytological and histological specimens made from the Cellstic sponges 1 to 92 hours after operation. As early as one hour after Cellstic implantation some bright fluorescent spots could be seen in the cytological specimens, although cell morphology still fully resembled to that of peripheral blood. The intensity of the fibronectin fluorescence increased rapidly until the maximum was reached 24-48 hours after surgery. Thereafter the fluorescence gradually decreased to the level of the first hours. Rapid appearance of fibronectin, its abundance on the second day and gradual diminution upon the activation of type I collagen synthesis indicate its role as a biological guide for localization of cellular activity in wound repair.

Adolescent↗
PubMed1980

Synthesis of hyaluronic acid and collagen in skin fibroblasts cultured from patients with osteogenesis imperfecta.

Collagen and hyaluronic acid syntheses were studied in skin fibroblast cultures from patients with osteogenesis imperfecta and age-matched controls by labeling the cultures either with [3H]proline and separating the collagenous proteins with DEAE- and CM-cellulose chromatographies, or double-labeling the cultures with [3H]glucosamine and [14C]glycine and separating radioactive hyaluronic acid from glycoproteins and sulphated proteoglycans by DEAE-cellulose chromatography. The activities of the cell layer hyaluronate synthesizing enzyme complex (hyaluronate synthetase) were also determined. The osteogenesis imperfecta cultures were classified into three variants on the basis of type III collagen synthesis. Type III collagen amounted to approx. 40--50% from total collagen in the first variety and approx. 25--30% in the second variety. No difference was noted in the ratio of type III collagen to total collagen in the third variety in comparison with control cultures. The radioactivities of 3H-labeled hyaluronic acid in DEAE-cellulose chromatograms were compared with those of the 14C-labeled proteins. The ratios ranged 9.2--17.3 in the cultures from the patients and 4.6--8.8 in the control cultures. Hyaluronate synthetase activities were 1.3--2.0-fold higher in the osteogenesis imperfecta cells than in their controls. Increased hyaluronic acid synthesis in skin fibroblasts correlated with the severity of the disease but not with the increase in type III collagen synthesis.

Adolescent↗
PubMed1980

Cortisol decreases the synthesis of hyaluronic acid by human aortic smooth muscle cells in culture.

The effect of cortisol on the synthesis of glycosaminoglycans (GAGs) was studied in cultured human aortic smooth muscle cells. Cortisol, at a level slightly exceeding the physiological concentration (10(-6) M), decreased the synthesis of hyaluronic acid (HA) by 50% but had no significant effect on the synthesis of sulphated GAGs. The ratio of HA to sulphated GAGs decreased by 47%. These effects were most marked in the fraction secreted into the culture medium. Cortisol neither affected the activity of the hyaluronic acid synthesizing enzyme complex in a cell-free system nor the molecular weight distribution of hyaluronic acid. We suggest that the atherogenity of cortisol and stress may be associated with their effect on the synthesis of HA by the smooth muscle cells of the arterial wall.

Aorta↗
PubMed1980

A rapid assay to measure collagen synthesis in cell cultures.

Limited pepsin digestion and precipitation of resistant parts of proteins with perchloric acid on glass-fiber filters has been used as a rapid way to determine the radioactive collagen secreted into fibroblast culture media. The specificity of the pepsin cleavage was tested by digesting [14C]- or [3H]proline- and [3H]tyrosine-labeled procollagens. Radioactivities obtained with this method were comparable with those obtained with collagenase digestions or hydroxyproline determinations. Dialysis of the samples is avoided and the radioactive collagen can thus be determined from the small medium samples obtained from microtest plates. The method was used to localize a collagen synthesis-increasing factor in preparative isoelectric focusing of microphage culture media.

Animals↗
PubMed1980

An arthropathic form of osteogenesis imperfecta.

A 14-year-old girl gradually developed severe osteoporosis and destructive generalized joint disease, resulting in joint stiffness and anchyloses. She also had moderate hydroxyprolinemia and hydroxyprolinuria. Rheumatoid arthritis was highly unlikely. Anamnestic data revealed two long bone fractures. Collagen biosynthesis was studied in fibroblasts cultured from the patient's skin. Chromatograms of 3H-labelled culture media proteins on ion exchange celluloses revealed an increased ratio of type III collagen to type I collagen when compared with the chromatograms of age-matched control fibroblasts. This finding is typical of certain cell strains in osteogenesis imperfecta. The patient might thus express a new variety of osteogenesis imperfecta with chronic arthropathy.

Adolescent↗