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S C Benson

Publications and source records attributed to S C Benson.

9 recordsLinked to original sources
PubMed1987

The effect of cyclic AMP on the accumulation of newly synthesized protein in the extracellular matrix of PFHR-9 teratocarcinoma cells.

The effect of elevated cyclic AMP levels on the accumulation of newly synthesized extracellular matrix protein was examined in PFHR-9 cells producing Type IV collagen. The effect of dbcAMP, 8-BrcAMP, IBMX and forskolin on the synthesis of total protein, non-collagen protein and collagen were compared. DbcAMP increased the accumulation of total protein but did not affect the distribution of collagen and non-collagen protein. 8-BrcAMP, IBMX and forskolin also increased collagen and non-collagen accumulation. However, the effect on collagen was significantly greater with 8-BrcAMP and IBMX. Consequently, 8-BrcAMP and IBMX resulted in an increased percent collagen synthesis in the extracellular matrix. Elevated cAMP levels had no effect on cell proliferation or DNA synthesis but did produce a significant effect on cell morphology.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Regulation of lung fibroblast proliferation and protein synthesis by bronchiolar lavage in experimental silicosis.

Male Sprague-Dawley rats were subjected to a single, intratracheal instillation of 30 mg Min-U-Sil silica in sterile saline and were sacrificed 3, 7, or 14 days following instillation. Control animals were instilled with sterile saline only. Silica instillation produced an inflammatory reaction followed by histological changes characteristic of lung fibrosis. Thickened alveolar septa associated with inflammatory cells transforming into large multifocal fibrotic nodules were detected in silica-exposed animals. Increased numbers of bronchoalveolar cells (principally macrophages), elevated levels of protein (principally serum albumin), and lysozyme, proteolytic (trypsin-like), and myeloperoxidase activities were detected in lavage fluids obtained from animals instilled with silica. These factors (except for lysozyme activity) were elevated above control levels from 3 to 7 days postinstillation and declined to near control levels by Day 14. The rate of DNA, collagen, and noncollagen protein synthesis was significantly elevated in lung tissue minces from silica-treated rats 3 and 7 days after instillation. Elevated levels of total protein, and lung collagen in particular, were observed 9 weeks after insult. Lavage fluid from silica-instilled rats stimulates DNA synthesis in cultures of proliferating and quiescent rat lung fibroblasts. Lavage fluid from silica-instilled rats also stimulates lung fibroblasts to increase collagen and noncollagen protein synthesis.

Animals↗
PubMedDate not supplied

Immunogold detection of glycoprotein antigens in sea urchin embryos.

Four developmental stages of sea urchin embryos were labeled with colloidal gold in an attempt to elucidate the intracellular trafficking patterns within the cells that produce the glycoprotein matrix of the embryonic spicule. The primary mesenchyme cells (PMCs) form a syncytium and secrete an organic matrix on which calcium carbonate is laid down to form an endoskeletal spicule. The organic matrix has been isolated and characterized as glycoprotein consisting of four major bands. Polyclonal antibodies to these glycoproteins were used to label embryos from the mesenchyme blastula, early gastrula, late gastrula, and plutei stages of development. The label is concentrated in the Golgi complex and associated vesicles, in secretory vesicles, and in the organic matrix. The density of the labeling increases as development proceeds.

Animals↗
PubMedDate not supplied

Regulation of lung fibroblast proliferation and collagen synthesis by alveolar macrophages in experimental silicosis. I: Effect of macrophage conditioned medium from silica instilled rats.

Alveolar macrophages were lavaged from silica or saline instilled rats 0, 3, 7 and 14 days after exposure. Macrophages were cultured for twenty-four hours and the conditioned media assayed for the ability to stimulate rat lung fibroblast proliferation and collagen synthesis. Macrophages remained viable throughout the culture period. DNA synthesis was significantly elevated by macrophage conditioned media (MCM) from silica instilled rats (S-MCM) compared to untreated fibroblasts or fibroblasts exposed to MCM from saline instilled control animals (C-MCM). Stimulation of DNA synthesis was not observed when S-MCM was exposed to non-proliferating fibroblasts. Collagen synthesis quantitated as 3H-hydroxyproline accumulation or percent collagen synthesis was also increased by day 3 and day 7 S-MCM. Specific activity measurements of intracellular 3H-proline minimized the possibility that the increase in 3H-proline incorporation into collagen was a reflection of increased proline transport. Non-collagen protein synthesis was also increased in fibroblasts exposed to day 14 S-MCM. These results suggest that alveolar macrophages elaborate factors following silica exposure capable of altering the DNA and protein synthetic activity of lung fibroblasts. These changes in fibroblast DNA and protein metabolism are similar to those observed for lung tissue in vivo and lend further support to the hypothesis of macrophage mediation of the pulmonary response following silica exposure.

Animals↗