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Biomedical subjects

W R Wood

Publications and source records attributed to W R Wood.

10 recordsLinked to original sources
PubMed1990

Retinoic acid inhibition of human melanoma cell invasion through a reconstituted basement membrane and its relation to decreases in the expression of proteolytic enzymes and motility factor receptor.

Treatment of four A375 human melanoma sublines (A375, A375P, A375P-5, A375M), exhibiting distinct metastatic potentials in vivo, with beta-all-trans-retinoic acid in vitro caused a dose- and time-dependent inhibition of the ability of these cells to penetrate Matrigel-coated filters using a reconstituted basement membrane invasion assay. The possible mechanisms of action responsible for the antiinvasive effect were further investigated, and the data showed that compared with untreated cells the retinoic acid-treated cells: (a) secreted lower levels of collagenolytic enzymes, as demonstrated by a decreased ability of the cells to degrade [3H]proline-labeled type IV collagen substrate and by a reduction in the activity of a secreted Mr 64,000 collagenolytic enzyme detected in type IV collagen-containing polyacrylamide gels; (b) expressed lower levels of the human type IV collagenase mRNA (except in the A375P cells), as detected by Northern blot analysis; (c) exhibited decreased levels of tissue plasminogen activator activity, as demonstrated by a chromogenic assay; (d) were 10-40% less adhesive to a reconstituted basement membrane matrix, as determined by a 60-min Na2(51)CrO4-labeled cell attachment assay; (e) exhibited an increase in the high affinity metastasis-associated cell surface laminin receptor, as determined by flow cytometry after binding of fluorescently labeled laminin receptor antibody; and (f) expressed decreased amounts of gp78, a cell surface receptor for motility factor, demonstrated by immunoblotting and immunofluorescence. Collectively, these data suggest that retinoic acid inhibits tumor cell invasion through a basement membrane-like matrix by suppressing matrix degradation and by altering cell surface receptors.

Basement Membrane↗
PubMed1989

Inhibition by retinoic acid of type IV collagenolysis and invasion through reconstituted basement membrane by metastatic rat mammary adenocarcinoma cells.

The activity of type IV collagenase, which enables tumor cells to degrade collagen type IV found in the subendothelial basement membrane, has been correlated with the metastatic potential in several tumor types, including the rat 13762NF mammary adenocarcinoma cell line and its clones. In this study, we examined whether all-trans-retinoic acid (all-trans-RA) and other retinoids, which exhibit antitumor activity in vitro and in vivo, affect the collagenolytic activity of metastatic rat 13762NF mammary adenocarcinoma cells. Cells of the highly metastatic lung-colonizing clone MTF7.T35.3, derived from the 13762NF cell line, were treated for 3 days with 0.1, 1, or 10 microM all-trans-RA, harvested, and seeded on [3H]proline-labeled extracellular matrix deposited by cultured rat lung endothelial cells or on a film of purified [3H]proline-labeled type IV collagen. The amount of radioactivity released into the medium during the subsequent 24 to 72 h was measured, and it was found that all-trans-RA treatment inhibited degradation of extracellular matrix and type IV collagen by 50 to 60%. This effect was observed whether the cells had been treated with all-trans-RA in serum-free medium or in medium supplemented with heat-inactivated or acid-treated fetal bovine serum. The growth of the cells was not inhibited under these conditions, except after treatment with 10 microM all-trans-RA in serum-free medium. The reduction in collagenolytic activity was observed in viable cells as well as in conditioned medium. A 24-h exposure of cells to all-trans-RA was sufficient to cause a 30% decrease in the collagenolytic activity, and this inhibitory effect was reversible. The direct addition of all-trans-RA to conditioned medium had no effect on secreted collagenase activity. The apparent molecular weights of the collagenolytic enzymes were determined by electrophoresis of cell extracts and concentrated conditioned medium in type IV collagen-embedded polyacrylamide gels followed by renaturation and activation of the enzymes within the gels. Two major type IV collagenolytic metalloproteinases exhibiting molecular weights of 64,000 and 88,000, respectively, were detected by this method. These two enzymes were also found to have specificity for gelatin. The Mr 64,000 enzyme could be extracted from viable cells (presumably from the cell membrane) by 2% 1-butanol. Treatment with all-trans-RA decreased the level of these enzymes in the cellular, cell membrane, and conditioned medium compartments.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1989

Tooth loss in patients with moderate periodontitis after treatment and long-term maintenance care.

Records of 63 patients diagnosed as having moderate periodontitis who had been treated and maintained by scaling and root planing for 10 years or longer (mean 13.6 years, range 10 to 34 years) in dental school clinics were reviewed for tooth loss. The patients averaged 45 years of age (range 24 to 67 years) at the initial appointment, and 41 were female. Record audit determined type of periodontal treatment, total tooth loss, periodontally related tooth loss, loss of teeth with furcation invasion, plaque scores, and maintenance interval. Results of therapy were evaluated by groups on the basis of number of teeth lost. At the completion of active periodontal therapy 1,607 teeth were present in the patients. During the maintenance period, 115 teeth (7.1%) were lost and of these 88 (5.0%) were lost due to periodontal reasons. Maxillary and mandibular molar teeth, particularly maxillary second molars, were the teeth lost most frequently to periodontal disease. Of the 164 teeth initially indicated as having furcation invasion, 23% were subsequently lost. This retrospective study confirms the low rate of tooth mortality occurring when patients with periodontal disease are treated and kept on a maintenance program. Canines were the teeth least frequently lost.

Adult↗
PubMed1982

Three case-type classifications: suitability for use in reimbursing hospitals.

This study compared three case-type classifications--the cross-classification of the Commission on Professional and Hospital Activities, Diagnosis-Related Groups (DRGs) and Staging--with respect to per cent of variance in total patient charges accounted for. The purpose was to assess the relative usefulness of the classifications for application in hospital reimbursement schemes. The sample consisted of 50 hospitals. A nested analysis of variance was performed with case type nested within hospital. Per cent of variance accounted for was calculated for each of three data sets: the full data set, a truncated version of that set and a logarithmically transformed version. Results support the contention that none of the currently available classifications accounts for enough variance to permit straightforward use of case-type standard costs in a reimbursement mechanism. New developments in case-type classification may result in a classification that is more suitable for this use.

Analysis of Variance↗
PubMed1981

Case mix complexity differences between teaching and nonteaching hospitals.

In the study reported here, the authors measured the differences between teaching and nonteaching hospitals in case mix complexity and provided some detail concerning the differences. They measured case complexity in a sample of 200 short-term general hospitals by the Resource Need Index (RNI) using a cross-classification of 3,490 case types with weights compiled from patient charges. Median RNI values were moderately higher for teaching than for nonteaching hospitals both for the hospital as a whole and for each clinical service except obstetrics-gynecology. The most resource-intensive case type were relatively more frequent in the teaching hospitals, but the least resource-intensive types were of about equal relative frequency in the two hospital groups. The results show that teaching hospitals could be expected to cost somewhat more per patient even if case mix were the only factor.

Costs and Cost Analysis↗
PubMed1979

Diffusion and nucleation of gas in gel and some implications for the development of decompression procedures.

Attention is directed to certain incongruities among accepted diving procedures in order to emphasize the need for a more complete understanding of the interactions between the factors involved in diving and decompression and in the onset of decompression sickness. It is suggested that physiological responses derived from the effects of diffusion and nucleation of gas in tissue might be interpreted in terms of similar events in specimens of gelatin subjected to patterns of compression and decompression. A model for behavior of specimens in gel is developed and conformity with the results of a program of experimentation is demonstrated. With the insight provided by this model, a substantial analogy between important aspects of the behavior of gel and tissue is claimed and application of this model to the refinement and development of diving and decompression procedures is proposed.

Decompression↗
PubMed1976

Influence of operating room surface contamination on surgical wounds: a prospective study.

The influence of operating room contamination on wound infection rates in clean, clean-contaminated, contaminated, and septid procedures was studied by a prospective randomized study of 2,020 surgical wounds. Operating room surface contamination was assessed by the RODAC bacterial plate method. Control rooms uniformly received Wet-Vac cleaning between operations. Experimental rooms were not cleaned between consecutive clean operations, but were cleaned after contaminated operations. The difference in surface contamination between groups of experimental and control rooms was found to be significant at the P less than .05 level. Patients operated on in experimental and control rooms were followed up postoperatively to assess whether they experienced wound infection. No statistically significant differences in wound infection rates were found between experimental and control room operations as total groups, clean procedures, or operations of long duration.

Bacteria↗
PubMedDate not supplied

Retinoic acid inhibits human melanoma tumor cell invasion.

The anticancer effects of retinoids have been recognized both in vivo and in vitro; however, little is known about their mechanism of action. Our study evaluated the effects of retinoic acid on the invasiveness of four human melanoma cell lines in vitro and showed a time-dependent inhibition of the ability of these cells to penetrate matrigel-coated filters. The possible mechanisms of action responsible for the anti-invasive effect were further investigated, and the data showed that retinoic acid-treated cells: (a) secreted lower levels of collagenolytic enzymes detected in type IV collagen-containing polyacrylamide gels compared with control cells, which was demonstrated by a decreased ability to degrade [3H]proline-labeled type IV collagen substrate; (b) showed a reduction in PA activity, primarily in the form of tPA, as demonstrated by chromogenic analysis; (c) showed a heterogeneous response with regard to c-myc, c-fos and c-jun mRNA expression, as determined by Northern blot analysis; and (d) demonstrated a decrease in B-actin levels and an increase in vimentin, as demonstrated by Northern blot analysis and SDS-PAGE transblot analysis. Collectively, these data suggest that RA causes an inhibitory effect on tumor cell invasion through a reconstituted basement basement membrane matrix by suppressing type IV collagenolytic activity and PA activity, which is probably triggered through a complex series of oncogene trans-acting factors, ultimately affecting cytoskeletal expression.

Actins↗