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Biomedical subjects

J Uitto

Publications and source records attributed to J Uitto.

At least 505 records · Page 28Linked to original sources
PubMed1980

Morphea and lichen sclerosus et atrophicus. Clinical and histopathologic studies in patients with combined features.

Ten patients with skin lesions clinically consistent with morphea and lichen sclerosus et atrophicus were studied. In all cases, histopathologic changes of both morphea and lichen sclerosus et atrophicus were also present. The coexistence of morphea and lichen sclerosus et atrophicus in the same patient suggests that these lesions represent a spectrum which may reflect similar etiologic events or closely related pathologic processes in these two diseases.

Adolescent↗
PubMed1980

Comparison of nerve cell and nerve cell plus Schwann cell cultures, with particular emphasis on basal lamina and collagen formation.

The availability of cultures of normal cells (NCs) and Schwann cells (SCs) with and without fibroblasts has allowed us to investigate the sources of endoneurial and perineurial constituents of peripheral nerve. NCs cultured alone, devoid of ensheathment but healthy in appearance, lack basal lamina and extracellular fibrils. In contrast, when SCs accompany NCs, basal lamina and extracellular fibrils are consistently visible around SCs in outgrowth areas formed de novo in culture. These fibrils average 18 nm in diameter, exhibit a repeating banding pattern, and are trypsin-resistant and collagenase-sensitive. Collagen synthesis is also indicated by the incorporation of [14C]proline into peptide-bound hydroxy-proline in NC + SC or SC cultures. That the [14C]hydroxyproline polypeptides formed in NC + SC cultures are collagenous was determined in part by pepsin digestion-ammonium sulfate precipitation-polyacrylamide gel electrophoresis techniques; the 14C-polypeptides migrate to the positions of alpha 1 (I), alpha 2, alpha 1 (III), and alpha B chains of type I, type III, and A-B collagens. Also formed are thin, ruthenium red-preserved strands interconnecting basal laminae. SC ensheathment of axons is similar to that found in the animal; one SC is related to a number of unmyelinated axons or a single myelinated axon. This proclivity to ensheathe and myelinate axons indicates that SC function is not lost during the preparative procedures or after lengthy isolation in culture and provides the most reliable means for SC identification. Perineurial ensheathment and macrophages are lacking in NC + SC culture preparations divested of fibroblasts. We conclude that SCs do not form perineurium or the larger diameter collagen fibrils typical of endoneurium but that in combination with neurons they generate biochemically detectable collagens and morphologically visible basal lamina and thin collagenous fibrils.

Animals↗
PubMed1980

Lung collagen in type IV Ehlers-Danlos syndrome: ultrastructural and biochemical studies.

A patient with type IV Ehlers-Danlos syndrome developed recurrent pneumothoraces. At operation for poudrage of the pleura, an apical bulla was resected. Biochemical analysis of the lung tissue revealed increased solubilization of collagen by acetic acid extraction and by pepsin proteolysis. The relative proportion of type III collagen in the pepsin-solubilized collagen fraction was markedly decreased. Fibroblasts cultured from the patient's lung produced less type III procollagen relative to type I procollagen than control lung fibroblasts. Electron microscopic examination of the lung tissue showed dilated endoplasmic reticulum of the fibroblasts, and collagen fibers were normal. These observations suggested that the structural abnormalities in the lung that led to pneumothorax in this patient were due to deficiency of type III collagen.

Adult↗
PubMed1980

Increased collagen cross-linkages in experimental diabetes: reversal by beta-aminopropionitrile and D-penicillamine.

The effects of diabetes on collagen cross-link formation and solubility were investigated in granulation tissue collagen induced by polyester fabric implanted subcutaneously in rats at the same time diabetes was produced by injection of streptozotocin. Thus, all the collagen analyzed was formed in a diabetic milieu. Ten days later the implants were removed and the total collagen content as well as the fraction soluble in 0.5 M acetic acid was determined. Predominantly type I collagen accumulated in the implants. Total collagen content was the same in diabetics and controls; however, the acid-soluble fraction in diabetic animals was only half that of controls (8.5% and 17.7%, respectively), and the ratio of beta chains to alpha chains in the acid-soluble fraction was higher in diabetics (0.89) than in controls (0.69). In animals treated with beta-aminopropionitrile or D-penicillamine the acid-soluble fraction of collagen from diabetics equaled that from controls. These observations indicate that both intramolecular and intermolecular cross-links are increased in type I collagen from diabetic animals. Since these cross-links interfere with degradation of collagen by collagenase, they may contribute to accelerated intimal sclerosis of arteries and to capillary basement membrane thickening in diabetes.

Amino Acids↗
PubMed1980

Collagen biosynthesis in bleomycin-induced pulmonary fibrosis in hamsters.

Bleomycin results in pulmonary interstitial fibrosis characterized by accumulation of collagen. We studied the mechanisms of this accumulation in hamsters 4 to 24 days after intratracheal injection of 1 U of bleomycin. Lung collagen was significantly increased within 11 days. Collagen synthesis was increased 10-fold in explant cultures obtained 8 days after injection. Prolyl hydroxylase activity and the degradation of newly synthesized collagen were also increased proportionally to collagen synthesis. Total protein synthesis also increased but not as much as collagen synthesis. We conclude that the accumulation of collagen in the lung following proceeds from an increased rate of collagen synthesis that is maximal early after injection and persists for at least 24 days after exposure.

Animals↗
PubMed1980

Connective tissue nevi of the skin. Clinical, genetic, and histopathologic classification of hamartomas of the collagen, elastin, and proteoglycan type.

Connective tissue nevi of the skin are hamartomatous lesions consisting predominantly of one of the components of the extracellular matrix, namely, collagen, elastin, or glycosaminoglycans. On the basis of clinical, histopathologic, and genetic considerations, the connective tissue nevi can be classified into defined categories. Association with extracutaneous features allows further delineation of these disease entities and aids in establishing an accurate diagnosis.

Adolescent↗
PubMed1979

Increased collagen prolyl hydroxylase activity in the aortic wall of rabbits exposed to chronic hypoxia.

The activity of collagen prolyl hydroxylase in aortic wall was studied in rabbits exposed to chronic 10% ambient oxygen tension for 30 days. Prolyl hydroxylase in rabbit aorta was shown to be similar to the enzyme from other sources in that it required molecular oxygen, alpha-ketoglutarate, ferrous iron and ascorbate for its activity. The activity of prolyl hydroxylase was increased to 180% of controls in the intima-media samples from rabbits exposed to hypoxia. No atherosclerotic lesions could be seen in arteries of animals kept in chronic hypoxia. If the arteries of rabbits were injured with a single mechanical dilatation, the activity of prolyl hydroxylase increased more than 2-fold, as reported previously. The exposure of these animals to chronic hypoxia further elevated the prolyl hydroxylase activity.

Animals↗
PubMed1979

Biochemistry of the elastic fibers in normal connective tissues and its alterations in diseases.

The elastic fibers present in various connective tissues of the body are responsible for physiologic elasticity of the organs. These fibers consist of 2 distinct components, elastin and the elastic fiber microfibrils. Controlled synthesis and balanced interaction of these 2 components are essential for normal fibrillogenesis. The intracellular biosynthesis of elastin by connective tissue cells, such as smooth muscle cells, involves assembly of the polypeptide chains on the membrane-bound ribosomes, hydroxylation of some prolyl residues to hydroxyproline, and secretion of the polypeptides packaged in Golgi vacuoles. In the extracellular space the elastin molecules assemble into fiber structures which are stabilized by the synthesis of complex covalent cross-links, desmosines. Recently, aberrations in the structure or metabolism of elastin have been detected in a variety of heritable and acquired diseases affecting skin and other connective tissues. These conditions include pseudoxanthoma elasticum, cutis laxa, and elastosis perforans serpiginosa, as well as arteriosclerosis and other degenerative changes of the vascular connective tissues.

Amino Acids↗
PubMed1979

Familial cutaneous collagenoma: genetic studies on a family.

Familial cutaneous collagenoma is an inherited condition characterized by the presence of multiple dermal nodules symmetrically distributed on the trunk and upper arms. In this study, six patients, the proband, his four siblings and a niece, representing a kindred of fifty-two subjects, were examined for aymptomatic cutaneous nodules mainly on the back and chest. The individual lesions varying from a few millimetres to several centimetres in size, were indurated, and showed minimal epidermal changes. Histologically, the nodules were characterized by an excessive accumulation of dense, coarse collagen fibres in the dermis. The elastic fibres appeared diminished in number, and in some areas they were abnormally thin and fragmented. The lesions, therefore, were connective tissue naevi of the collagen type. On the basis of the family history and histological observations the patients were diagnosed as having familial cutaneous collagenoma. Examination of the family pedigree indicated that the dermal nodules in familial cutaneous collagenoma were inherited in an autosomal dominant pattern. It was also observed that the lesions had an onset at the age of 15 to 19 years, and their number increased significantly during pregnancy. It is conceivable that familial cutaneous collagenoma is an inherited condition whose expression may be under a hormonal control.

Adolescent↗
PubMed1979

Chromomycosis. Successful treatment with 5-fluorocytosine.

A case of chromomycosis, caused by Fonsecaea pedrosoi, was treated with 5-fluorocytosine. After 18 weeks of treatment the initial lesions had largely resolved, and no evidence of active disease was observed clinically, histologically or from fungal cultures of the biopsy material. Further resolution of the remaining hypertrophic scar was achieved by intralesional injections of triamcinolone acetonide. Minimal side-effects were encountered during the therapy, and no recurrence during an 18-month follow-up period was observed. The results of this study indicate that 5-fluorocytosine is an effective and relatively safe mode of therapy in chromomycosis.

Adult↗
PubMed1979

Scleroderma: increased biosynthesis of triple-helical type I and type III procollagens associated with unaltered expression of collagenase by skin fibroblasts in culture.

To assess potential abnormalities in collagen metabolism in systemic scleroderma, skin fibroblast lines from patients with this disease were established and compared to control cell lines derived from healthy subjects. For studies on the biosynthesis of procollagen, the cells were incubated with [(14)C]proline in a medium supplemented with ascorbic acid and beta-aminopropionitrile, and the synthesis of nondialyzable [(14)C]hydroxyproline, in relation to DNA or cell protein, was taken as an index of procollagen formation. Five of eight scleroderma fibroblast cell lines demonstrated procollagen biosynthesis rates significantly higher than the controls, and the mean rate of procollagen synthesis by scleroderma fibroblasts was about twice that of the control cells. Control experiments demonstrated that the specific activity of the intracellular free proline was not different in scleroderma and control fibroblasts, and the mean population doubling times of the scleroderma and the control fibroblast cell lines were the same. The relative synthesis of the genetically distinct procollagens was examined by isolating type I and type III procollagens from the cell culture medium using DEAE-cellulose chromatography. The ratios of type I/III procollagens in scleroderma cell lines did not differ from the controls. The helical stability of the collagenous portion of type I and type III procollagens, estimated by the resistance of (14)C-collagen to limited proteolytic digestion with pepsin under nondenaturing conditions, was the same in both scleroderma and control cultures. The capacity of the cells to synthesize enzymatically active and immunologically reacting collagenase was also studied; no marked differences in these parameters could be observed. The results suggest that cultured skin fibroblasts from patients with scleroderma demonstrate a metabolic abnormality expressed as increased synthesis of type I and type III procollagens in a normal ratio. This abnormality may play a role in the excessive accumulation of collagen in the skin and other organs affected in scleroderma.

Adolescent↗
PubMed1979

Enhanced collagenase production by fibroblasts derived from human basal cell carcinomas.

Fibroblast cultures derived from human basal cell carcinomas demonstrated an increased capacity to synthesize and secrete collagenase. Although the levels of collagenase were up to 8-fold greater than those of normal control cell lines, this phenotypic trait was not permanent and was expressed only for a few passages following primary explanation. The basal cell carcinoma fibroblast collagenase was secreted as a proenzyme. The kinetics of activation and the catalytic efficiency of the basal cell carcinoma fibroblast enzyme were equal to control collagenase, indicating that increased activity was due to increased synthesis of enzyme protein. Increased synthesis of collagenase was not due either to altered cell growth or to an overall increase in protein synthesis. Furthermore, synthesis of another major protein, of another major protein, collagen, was not enhanced. The data suggest that the tumors may have stimulated adjacent fibroblasts to produce more collagenase which is of importance in tumor invasion.

Basal Cell Carcinoma↗