PubMed Health⌕ Search

Biomedical subjects

D W Rowe

Publications and source records attributed to D W Rowe.

At least 91 records · Page 5Linked to original sources
PubMed1979

Regulation of procollagen synthesis during the development of chick embryo calvaria. Correlation with procollagen mRNA content.

During the embryonic development of chick calvaria (membranous cranial bones), the relative rate of procollagen synthesis increased from about 12% of total protein synthesis on Day 10 to about 65% on Day 17. This increase is due to a 1.7-fold increase in the absolute rate of procollagen synthesis and a 3-fold decrease in the synthesis of noncollagenous proteins. The increase in procollagen synthesis is directly proportional to an increase in procollagen mRNA content per cell as measured either by cell-free translation or by hybridization with complementary DNA. The results indicate that translational control of procollagen mRNA does not play a substantial role during calvaria development and that the specialization in the synthesis of this protein is largely due to the loss or inactivation of mRNAs for noncollagenous proteins.

Animals↗
PubMed1979

NH2-terminal sequence of the chick proalpha1(I) chain synthesized in the reticulocyte lysate system. Evidence for a transient hydrophobic leader sequence.

Translation of chick procollagen mRNA in a reticulocyte lysate system yields a larger proalpha1(I) chain than is observed in vivo. The NH2-terminal sequence of this putative precursor, determined by automated radiosequencing, is Met-Phe-Ser-Phe-Val-X-Ser-Arg-Leu-Leu-Leu-Leu-Ile-Ala-Ala-X-X-Leu-Leu. This sequence closely resembles the transient hydrophobic leader (signal) sequences observed on most secreted proteins. When synthesized in the presence of microsomal membranes from dog pancreas, which contain signal peptidase activity, proalpha chains with the electrophoretic mobility of underhydroxylated procollagen polypeptides synthesized in vivo are produced. Estimates of the molecular weight of the NH2-terminal extension of the precursor suggest that the leader sequence may be longer than those commonly found in precursors of secreted proteins.

Amino Acid Sequence↗
PubMed1978

Inhibitory effects of glucocorticoids on collagen synthesis by mouse sponge granulomas and granuloma fibroblasts in culture.

The basis for the glucocorticoid-mediated decrease in tissue collagen was studied in mouse granulomas and in primary granuloma fibroblast cultures. Injection of mice for 12 days with dexamethasone (0.35 mg/kg body weight) resulted in a 50--70% inhibition of collagen synthesis and accumulation in polyvinyl sponge-induced granulomas whereas total protein synthesis was inhibited by only about 25%. The decreased collagen content of the granuloma was accounted for by both a reduced fibroblast number and diminished synthesis per cell. Growth rates, total protein synthesis and collagen synthesis were the same in granuloma fibroblast cultures derived from control or steroid-treated mice. However, addition of 3.10(-7) M hydrocortisone to the culture medium caused a 30--50% inhibition of both collagen and non-collagen protein synthesis in firbroblasts from either source. These inhibitory effects were dose- and time-dependent with a lag time of 12--24 h. Prolyl hydroxylase activity was reduced both in sponge granulomas from glucocorticoid-treated mice and in hydrocortisone-treated fibroblast cultures. However, protein synthesis was inhibited to the same extent as the inhibition of prolyl hydroxylase activity and there was no effect on peptidyl prolyl hydroxylation. These results indicate that the glucocorticoid-induced reduction of collagen synthesis and accumulation observed in mouse granulomas and primary granuloma fibroblast cultures is not specific for this protein. Furthermore, glucocorticoid-induced inhibition of collagen synthesis cannot be attributed to underhydroxylation of collagen prolyl residues.

Animals↗
PubMed1978

The effect of amphotericin B-deoxycholate on proliferation and protein synthesis in human skin fibroblast cultures.

Cultures of adult human skin fibroblasts were grown in the presence of the recommended antifungal dose (3 microgram per ml) of amphotericin B-deoxycholate. A reduction in cell culture growth, measured as DNA content and protein content per culture, was observed. However, radioisotope incorporation into noncollagen protein and, to a lesser extent, collagen protein was enhanced. These effects were due to amphotericin B, not to deoxycholate. These observations were made under several growth conditions and indicate that cell proliferation or isotope-labeling studies in fibroblasts in the presence of amphotericin B-deoxycholate are susceptible to errors in interpretation.

Amphotericin B↗
PubMed1978

Effects of component length and of the transitions among components in multiple schedules.

Pigeons received equal variable-interval reinforcement during presentations of two line-orientation stimuli while five other orientations appeared in extinction. Component duration was 30 seconds for all orientations and the sequence was arranged so that each orientation preceded itself and each other orientation equally often. The duration of one component (0 degrees ) was shortened to 10 seconds and the other (90 degrees ) was lengthened to 50 seconds. All animals showed large increases in response rate in the shortened component and this increase was recoverable after an interpolated condition in which all components were again 30 seconds in duration. This effect was replicated in a second experiment in which component duration was changed from 150 seconds to 50 seconds and 250 seconds. An examination of local contrast effects during the first experiment showed that the shortened component produced local contrast during subsequent presentations of the lengthened component, just as would a component associated with more frequent reinforcement. When the presentation sequence was changed so that the lengthened component was always followed by the shortened component, response rates generally increased during the lengthened component. When the sequence was arranged so that the shortened component always preceded the longer component, response rate decreased in the former. These effects, as well as the increases in response rate following change in component length, seem not to be the product of local contrast effects among components.

Journal Article↗
PubMed1977

Decreased lysyl oxidase activity in the aneurysm-prone, mottled mouse.

Inbred mice bearing certain alleles at the Mottled locus have defects in connective tissue which result in weakness of skin and of blood vessels. Previous studies have established that cross-links in collagen and elastin are decreased in these animals due to impaired formation of lysine-derived aldehydes. Lysyl oxidase activity in extracts of skin is markedly lower in those prepared from affected animals than control mice. An inhibitor of lysyl oxidase is present in equal amounts in affected and control skins and does not account for diminished activity found in affected animals.

Amino Acid Oxidoreductases↗
PubMed1977

Differences in growth response to hydrocortisone and ascorbic acid by human diploid fibroblasts.

The effects of hydrocortisone and ascorbic acid on growth parameters were measured in human diploid skin fibroblasts from fetal and adult donors. In the presence of culture medium containing 10% fetal bovine serum, 0.3 micrometer hydrocortisone produced a 20% increase in the population growth rate and a 50 to 70% increase in the confluent density of fibroblasts from adult donors. Daily addition of 28 micrometer ascorbic acid also stimulated the population growth rate and cell density at confluency. The effects of hydrocortisone and ascorbic acid on the final cell density were additive. The action of hydrocortisone was restricted to cells in log-phase growth, whereas ascorbic acid affected cells in both the log and the post-confluent phases of the growth cycle. In fibroblasts from fetal donors, ascorbic acid was stimulative but hydrocortisone was not. The data suggest that whereas both compounds stimulate cell growth in an additive manner, they do so by different cellular mechanisms.

Adult↗
PubMed1977

Abnormalities in proliferation and protein synthesis in skin fibroblast cultures from patients with diabetes mellitus.

Several aspects of in-vitro cell growth and protein synthesis were assessed in cultures of skin fibroblasts from subjects with juvenile-onset diabetes mellitus (JODM) or adult-onset diabetes mellitus (AODM) and from age-matched nondiabetic controls (C). There was an inverse correlation between increasing age and both the log-phase doubling rate and saturation density at confluence in C fibroblasts. JODM and AODM cells had a reduction in both indices of cell population growth in comparison with age-matched C fibroblasts. Fibroblasts grown in the presence of 0.3 micronM hydrocortisone were stimulated to grow more rapidly and to a greater saturation density. Stimulation of cell division by hydrocortisone accentuated the abnormalities in growth of JODM and AODM fibroblasts. Total protein and collagen synthesis was measured whtn the fibroblasts had grown to confluency in medium with or without hydrocorticone. Hydrocorticone did not produce a significant change in total protein and collagen synthesis per cell by C fibroblasts. Fibroblasts from AODM had a 180 per cent increase in total protein and collagen synthesis in the presence of hydrocortisone. In contrast, total protein and collagen synthesis decreased 40 per cent in fibroblasts from JODM when grown in the hydrocortisone medium. These studies indicate that skin fibroblast cultures from patients with diabetes exhibit abnormalities in cell proliferation. Furthermore, hydrocortisone appears to unmask diffeerences in protein synthesis that distinguish JODM and AODM fibroblasts in culture.

Adult↗
PubMed1975

Patients with Ehlers-Danlos syndrome type IV lack type III collagen.

One of the genetically distinct collagens (type III) normally found in skin, aorta, and intestine is missing from the tissues of patients with the Ehlers-Danlos syndrome type IV. While skin fibroblasts from other individuals synthesize both types I and III collagen. Ehlers-Danlos syndrome IV cells synthesize only type I. These results suggest that the fragile skin, blood vessels, and intestines of Ehlers-Danlos syndrome IV patients result from an absence of type III collagen.

Amino Acid Sequence↗
PubMed1974

A sex-linked defect in the cross-linking of collagen and elastin associated with the mottled locus in mice.

A genetic abnormality in collagen and elastin cross-linking resembling experimental lathyrism has been identified in mice. The defect is an X-linked trait, attributed to the mottled locus which also influences coat color. The affected mice have aneurysms of the aorta and its branches, weak skin, and bone deformities in a spectrum of severity varying with the alleles at the mottled locus. A defect in the cross-linking of collagen was demonstrated in the skin of the affected animals by a marked increase in collagen extractability and a reduced proportion of cross-linked components in the extracted collagen. A decrease in lysine-derived aldehyde levels was found in both skin collagen and aortic elastin similar to that found in lathyritic tissue. Furthermore the in vitro formation of lysine-derived aldehyde was reduced. Thus the cause of the connective tissue abnormalities in these mice appears to be a defect in cross-link formation due to an impairment in aldehyde formation.

Animals↗