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Biomedical subjects

J Sodek

Publications and source records attributed to J Sodek.

At least 145 records · Page 8Linked to original sources
PubMed1983

Effects of cells of epithelial rests of Malassez and endothelial cells on synthesis of glycosaminoglycans by periodontal ligament fibroblasts in vitro.

Cultures of fibroblast-like cells (PLF) and epithelial rest cells (PLE) prepared from explants of porcine periodontal ligament synthesized and secreted four glycosaminoglycans (GAG) in differing proportions. The PLF produced predominantly chondroitin sulfate (greater than 60%) with smaller amounts of hyaluronic acid (HA) (17%), dermatan sulfate (13%), and heparan sulfate (7%), whereas PLE produced predominantly HA (greater than 80%). In coculture and under conditions of reciprocal transfer of conditioned media neither cell type affected the other's GAG synthesis. Endothelial cells (EC), however, or their conditioned growth media, were able to stimulate increased GAG synthesis, especially HA, in PLF. A similar result was obtained with smooth muscles cells (SMC) cultured in EC growth media but here again PLE were unable to stimulate GAG synthesis by SMC. These findings suggest that the spectrum of GAG found in whole ligament results both from independent production by, and from interaction between, the different cell types within the ligament. The results also provide support for a general hypothesis that loose connective tissues, which are rich in HA, are formed and maintained under the influence of epithelial, including endothelial, cells.

Animals↗
PubMed1983

Independent expression of type I collagen and fibronectin by normal fibroblast-like cells.

A double-label immunofluorescence technique was used to determine whether all normal fibroblast-like cells cultured from porcine connective tissues simultaneously express both type I collagen and fibronectin (FN). Cells surrounding explants in primary cultures from gingival and periodontal ligament (PL) tissue were heterogeneous in the expression of collagen and FN. Mass population cells at first and second subculture after primary explanting of gingival tissue were also heterogeneous in the expression of collagen and FN. When clonal populations were analyzed, four distinct phenotypes were observed: Coll+/FN+;Coll+/FN-;Coll-/FN+;Coll-/FN-. Mass populations of PL cells were more homogeneous than gingival fibroblasts and when clones were analyzed only two phenotypes were observed. These data suggest that normal fibroblast-like cells in vitro are capable of expressing collagen and FN independently and that FN-negative cells may utilize a FN-independent attachment mechanism in culture.

Animals↗
PubMed1982

Characterization of the collagens synthesized by Chinese hamster ovary cells. Effect of colcemid and dibutyryladenosine cyclic monophosphate.

The collagens synthesized by Chinese hamster ovary cells have been isolated and characterized. Although these cells produce very small amounts of collagen, at least five distinct collagenous chains could be identified from radiolabeled media and cell extracts after limited pepsin digestion. Two chains were characterized as alpha 1(V) and alpha 2(V), based on electrophoretic mobility, resistance to vertebrate collagenase, chromatographic properties on carboxymethylcellulose, and cyanogen bromide peptide patterns. Two smaller collagenous proteins (Mr 34000 and 37000) were also isolated by carboxymethylcellulose chromatography and characterized by cyanogen bromide digestion patterns. These collagens showed similarities to type IV collagen fragments but may be unique to Chinese hamster ovary cells. A colcemid-resistant mutant of Chinese hamster ovary cells designated CMR795 [Ling, V., Aubin, J.E., Chase, A., & Sarangi, F. (1979) Cell (Cambridge, Mass.) 18, 423-430] was found to synthesize the same collagen chains but in different proportions. In the wild-type cells colcemid (0.05-0.1 microgram/mL) reduced the amount of type V collagen in the culture media but had little effect on the other collagen type, whereas the type V collagen reduction was less pronounced in the CMR795 cells treated with the same concentrations of colcemid. Dibutyryladenosine cyclic monophosphate caused a fibroblast-like "reverse transformation" of the Chinese hamster ovary cells similar to that described previously [Hsie, A.W., & Puck, T. T. (1971) Proc. Natl. Acad. Sci. U.S.A. 68, 358-361]. However, collagen synthesis was increased only slightly. Furthermore, no apparent alteration in the types of collagens synthesized was detected.

Amino Acids↗
PubMed1982

Metabolism of collagen types I, III, and V in the estradiol-stimulated uterus.

The synthesis and deposition of collagen in uterine tissues stimulated with 17 beta-estradiol was studied in ovariectomized nulliparous rats. Eight days after ovariectomy 200-g rats were given a single intraperitoneal injection of 100 micrograms of estradiol. [14C]Glycine, 1.5 mCi. was administered intraperitoneally 40 h later and the animals were killed between 0.5-6 h following isotope injection. Radiolabeled proteins were extracted from uterine tissues sequentially with 0.45 and 1.0 M neutral salt, 0.5 M acetic acid, 0.1 M penicillamine, and 4 M guanidine hydrochloride or pepsin digestion. The radiolabeled collagens from each pool were analyzed by a combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Types I, III, and V collagens were identified in uterine pools. In the salt-soluble pool, each collagen type underwent rapid maturation into salt-insoluble collagen, although the initial appearance of type V collagen was delayed in both salt-soluble and insoluble pools. Type I procollagens were rapidly converted to alpha-chains through pc-intermediates. At 0.5 h, 28% of the type I collagen was already in a alpha-chain form. Type II procollagen was also rapidly converted but to a more stable intermediate designated p alpha 1 (III). Radiolabeled procollagens were also observed in the acetic acid, penicillamine, and guanidine hydrochloride pools suggesting that collagen precursor molecules complex through covalent and noncovalent interactions with other connective tissue macromolecules. These results indicate that both procollagen conversion and collagen assembly can follow different pathways depending upon the nature of the collagen and the tissue studied.

Animals↗
PubMed1982

Collagen metabolism in rat incisor predentine in vivo: synthesis and maturation of type I, alpha 1 (I) trimer, and type V collagens.

Collagen synthesis and deposition in the predentine of the continuously erupting rat incisor was analyzed in vivo following a single intraperitoneal injection of [14C]glycine. Newly synthesized collagen was extracted from the dissected predentine with a solution of 1.0 m sodium chloride containing proteolytic enzyme inhibitors. Mature, cross-linked collagen was solubilized by limited pepsin digestion following extractions with 0.5 M acetic acid or 0.1 M penicillamine. Analysis of the radiolabeled collagens by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography showed that over 97% of collagen synthesized migrated in the alpha 1 (I) and alpha 2 positions following pepsin digestion; the remaining 3% migrated in the positions of alpha 1 (V) and alpha 3 (V) collagens. However, from the ratio of the alpha 1 (I): alpha 2 it was estimated that approximately 30% of the salt-extractable collagen was alpha 1 (I) trimer. The presence of this collagen was confirmed by salt-fractionation and cyanogen bromide digestion patterns. Type I, alpha 1 (I) trimer, and type V collagens were also found in the salt-insoluble tissue residue. In this fraction the alpha 1 (I) trimer comprised 10-15% of the collagen measured as radioactivity but was difficult to discern colorimetrically. Type III collagen could not be detected in any of the fractions analyzed. From the profiles of isotope incorporation into collagens and collagen precursors, it was evident that collagen synthesis and processing was rapid. Processing of type I collagen and probably also alpha 1 (I) trimer proceeded almost entirely through procollagen intermediates. Rapid maturation of the types I and V collagens in the salt-insoluble fraction and the appearance of beta and gamma chains as early as 30 min after isotope administration. Radiolabeled procollagens were also extracted with acetic acid and penicillamine, indicating that cross-linking of collagen precursors may be involved in fiber formation.

Animals↗
PubMed1982

Effect of ascorbic acid on protein synthesis and collagen hydroxylation in continuous flow organ cultures of adult mouse periodontal tissues.

A continuous flow organ culture system (CFCS) was used to determine the effect of ascorbic acid on the synthesis of collagen and noncollagenous protein by bone of the alveolar process and periodontal ligament in organ cultures of adult mouse periodontium. For the last 24 h of 2 day cultures, 5 microCi/ml 3H-proline was added to the medium. Highly purified collagenase was used to separate the collagenous and noncollagenous proteins and the incorporation of isotope into each fraction measured. Collage synthesized in the presence of less than 10 micrograms/ml ascorbic acid was found to be highly under-hydroxylated (pro:hypro ap. acts. 2.3-3.1) in both tissues. When the ascorbic acid levels were between 25 and 100 micrograms/ml, the synthesis of collagenous proteins was selectively stimulated and hydroxylation significantly improved (pro:hypro sp. acts 1.72-1.89). The effect of ascorbic acid was not related to tissue viability since tissues cultured initially in the absence of ascorbic acid were able to recover completely when compared to controls given ascorbic acid continuously. The proportion of radioactivity in collagen and noncollagenous protein, collagen hydroxylation, and percentage of collagen synthesized as type III (av.23%) in bone of the alveolar process was similar to that found in vivo. However, in the periodontal ligament in vitro the proportion of noncollagenous protein synthesized was increased from 70% to 87% and the percentage of type III collagen increased from 14% to 26% compared to in vivo results.

Alveolar Process↗
PubMed1982

Isolation of bone cell clones with differences in growth, hormone responses, and extracellular matrix production.

Clones of nontransformed hormone-responsive bone cells have been isolated in vitro from mixed cell populations of fetal rat calvaria. In several independent isolations, microscopically visible colonies appeared at plating efficiencies of 5-10% of the starting cell numbers. Of these clones, approximately 10% grew to mass populations which could be assayed for a number of growth and biochemical properties. Although some similarities existed among the clones, they could be distinguished from each other and from the mixed cell populations. Population-doubling times (tDs) and saturation densities varied over a wide range: e.g., tDs of 24-72 h and saturation densities of 0.4-5 x 10(5) cells/cm2. Morphologies varied from roughly polygonal multilayering cells to typically spindle-shaped monolayering cells. Hormone responsiveness, as measured by stimulation of cAMP by hormones, indicated that some clones were responsive to both parathyroid hormone (PTH) and prostaglandin E2 (PGE2), while others responded to PTH only. Analysis of extracellular matrix components revealed that all clones produced type I and type III collagens, though in different proportions. Similarly, although all clones synthesized four glycosaminoglycans (hyaluronic acid, heparan sulfate, chondroitin sulfate, and dermatan sulfate), the quantities of each were distinctive from clone to clone. Further investigation of such clones is continuing to define more precisely the heterogeneity of clonal bone cell populations in vitro. They represent an important step in the study of the endocrinology and differentiation of bone.

Animals↗
PubMed1980

Specific immunohistochemical localization of type III collagen in porcine periodontal tissues using the peroxidase-antiperoxidase method.

Specific antibodies to porcine gingival type III collagen were raised in sheep. After purification on collagen affinity columns the antibodies were used for immunohistochemical localization of type III collagen in porcine periodontal and dental tissues employing the peroxidase-antiperoxidase (PAP) procedure. The extent of staining of the periodontal tissues was found to approximate the amount of type III collagen measured biochemically. A fairly uniform distribution of type III collagen was observed in the periodontal ligament and gingiva with more intense staining often being associated with blood vessels. A regular pattern of weakly staining fibers could be demonstrated throughout the cementum and in parts of the alveolar bone tissue. In addition, occasional sites in the cementum having a different morphological appearance from the rest of the cementum exhibited bundles of positively stained fibers. Although the bone tissue was essentially unstained, fibers in the endosteal spaces stained strongly. Sharpey's fibers passing from the soft connective tissues into alveolar bone and cementum also stained strongly. Three distinct arrangements of collagen fibers stained by the type III collagen antibodies could be identified: first, a reticular pattern, which was seen at the junction of the gingival epithelium and connective tissue, and in the endosteal spaces and dental pulp; second, a more diffuse pattern of fibers intermingled with type I collagen in the soft connective tissues; and third, a coating of some Sharpey's fibers, having a core believed to be type I collagen, and of fibers in the cementum inclusions.

Amino Acids↗
PubMed1980

The effect of 17 beta-estradiol on collagen and noncollagenous protein synthesis in the uterus and some periodontal tissues.

The effect of a single dose of 17 beta-estradiol on collagen metabolism in the uterus and various oral tissues was determined in ovariectomized nulliparous rats. Eight days after ovariectomy, 200-g rats were given 100 micrograms estradiol ip. Forty hours later, 2 mCi [3H]proline were administered by ip injection, and the animals were killed 2 h later. The specific radioactivities of hydroxyproline and proline in both salt-soluble and salt-insoluble proteins were used as a measure of collagen and noncollagenous protein metabolism. Estradiol was found to induce a 2-fold increase in the specific radioactivity of newly synthesized collagen and an 8-fold increase in the specific radioactivity of the insoluble collagen in the uterus. The discrepancy between these results could be largely accounted for by a 2- to 3-fold increase in the size of the newly synthesized collagen pool. Stimulation of noncollagenous protein synthesis was also observed. The total collagen content of the uterus was not significantly altered in estradiol-treated animals, suggesting that estradiol stimulates both the synthesis and degradation of collagen. Using [14C]glycine as a precursor, the nature of the collagens synthesized in the uterus was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Estradiol was found to stimulate the synthesis of both type I and type III collagens, but no change in the pattern of procollagen conversion could be discerned. In contrast to the uterine tissues, the only significant effect of estradiol on protein metabolism in the oral tissues was a decrease in the newly synthesized collagen specific radioactivity in the molar periodontal ligament.

Animals↗