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Biomedical subjects

P J Rowling

Publications and source records attributed to P J Rowling.

7 recordsLinked to original sources
PubMed1994

A single purification procedure for the major resident proteins of the ER lumen: endoplasmin, BiP, calreticulin and protein disulfide isomerase.

We have developed a single purification procedure for the four major resident endoplasmic reticulum (ER) proteins: protein disulfide isomerase (PDI), BiP, endoplasmin, and calreticulin. Three of these proteins are thought to play a role in protein folding in vivo, whereas calreticulin is thought to be the major calcium binding protein in the ER. The proteins were purified from fresh bovine liver by taking advantage of individual characteristics of the proteins. Liver microsomes were prepared and then premeabilized to release the lumenal contents. After ammonium sulfate precipitation, the proteins were purified by chromatography; BiP was purified by affinity chromatography on ATP-agarose, and both endoplasmin and calreticulin were purified by affinity chromatography on Con A-Sepharose. PDI was purified by anionic ion exchange chromatography.

Amino Acid Sequence↗
PubMed1992

Folding in vitro of bovine pancreatic trypsin inhibitor in the presence of proteins of the endoplasmic reticulum.

The rates of folding and disulfide bond formation in reduced BPTI were measured in vitro in the presence and absence of total protein from the endoplasmic reticulum. The rates were increased substantially by the endoplasmic reticulum proteins, but only to the extent expected from the known content and activity of protein-disulfide-isomerase. No effects of added ATP or Ca2+ were observed, even though protein-disulfide-isomerase binds Ca2+ tightly.

Adenosine Triphosphate↗
PubMed1990

Fabrication and reorganization of dermal equivalents suitable for skin grafting after major cutaneous injury.

The incorporation of fibroblasts into a hydrated collagen lattice results in lattice contraction and collagen reorganization to form a dermal equivalent. Lattices fabricated with 7.7 mg collagen and seeded with 1 X 10(5) cells were found to give the best results in terms of their mechanical properties and ability to maintain cell viability. Newly-cast lattices were found to be completely digested by 0.085 units/ml bacterial collagenase in 3 h, whereas after 30 d in culture, limited digestion took place over 24 h. Electrophoretic analysis showed that the proportion of cross-linked collagen in the 30 d lattice was increased by 2.5-fold compared to the initial collagen preparation. These results indicate that a dermal equivalent better suited for grafting may be produced after 20-30 d in culture.

Animals↗
PubMed1984

The distribution of (Na+ + K+)-ATPase along the villus crypt-axis in the rabbit small intestine.

The migration of intestinal epithelial cells from the crypts to the tips of villi is associated with progressive cell differentiation. The changes in Na+-pump levels during migration have been measured in epithelial cells isolated from rabbit small intestine. A significant proportion of ouabain-sensitive (Na+ + K+)-ATPase in the cell homogenates was latent but could be unmasked by detergent treatment. Highest detergent activation was observed in villus cells. The distribution of pumping sites was also assessed by measuring ouabain binding to intact cells. The kinetics of specific binding was consistent with the interaction of the cardiac glycoside with a single population of binding sites with an apparent Kd of around 10(-7) M. Both enzyme assay and ouabain-binding measurements suggest that a 2-3-fold increase in the number of Na+-pumping sites accompanies cell differentiation in rabbit jejunal epithelium. This increase in pumping capacity might be an adaptation of the cells to their absorptive function.

Animals↗