PubMed Health⌕ Search

Biomedical subjects

D D Stewart

Publications and source records attributed to D D Stewart.

8 recordsLinked to original sources
PubMed1995

Expert role assignment and information sampling during collective recall and decision making.

Previous research has found that decision-making groups do not effectively pool unshared information. This study examined how personal expertise facilitates the mentioning and validation of unshared information in collective recall and decision-making groups by increasing members' awareness of who holds what types of information. Assigned expertise increased substantially the proportion of unshared information mentioned during both collective recall and decision-making tasks. Two results supported the hypothesis that assigned expertise provides validation for the recall of unshared information. When expertise was assigned, (a) more of the unshared information mentioned during the recall task was retained on the collectively endorsed written protocol, and (b) unshared information that was mentioned in discussion was more likely to be correctly recognized by members after group interaction.

Adult↗
PubMed1986

Chronic syndrome of inappropriate antidiuretic hormone secretion and hypertension in a patient with olfactory neuroblastoma. Evidence of ectopic production of arginine vasopressin by the tumor.

A 28-year-old man with the chronic syndrome of Inappropriate antidiuretic hormone secretion and hypertension was found to have an olfactory neuroblastoma. We demonstrated evidence of elevated circulating arginine vasopressin levels, significantly elevated arginine vasopressin and vasopressin neurophysin levels in the tumor extract, and immunohistochemical staining for arginine vasopressin and vasopressin neurophysin in the tumor cells. The patient's clinical syndrome, including hypertension, resolved following subtotal removal of the tumor and radiation therapy. This study identified olfactory neuroblastoma as a definite cause of ectopic arginine vasopressin secretion causing the syndrome of inappropriate antidiuretic hormone secretion.

Adult↗
PubMed1980

Passage of extravascular tracers into canine jugular veins and carotid arteries.

Biologically active substances arising in the interstitial space (cell-fiber matrix) of a medium-sized blood vessel or in surrounding tissue might reach the lumen by diffusion. Substances so delivered to the vessel wall-blood interface would be situated to effectively influence the endothelium and to initiate deposition of blood elements on the luminal surface of vessels, thereby contributing to thrombosis and atherosclerosis. This study showed that 125I, 125I-albumin and 125I-fibrinogen passed across the walls of segments of canine jugular veins and carotid arteries that were maintained under 20 cm H2O presure while being suspended in solutions containig the radioactive substances. The ratio of 125I to 125I-protein (albumin, fibrinogen) was predictably greatly increased by diffusion across the vessel wall. Frozen sections cut parallel with the luminal surface of flattened segments of vessels showed a gradient of radioactivity from adventitial to luminal surface of the vessels. Part of the fibrogen (but no albumin) that had reached the inside of the vessel had been broken down into fragments. These observations show that ions and proteins originating in perivascular fluid transverse the wall of medium-sized veins and arteries, presumably by diffusion across complex water-filled channels. Thus biologically active substances arising in perivascular tissue or in the vessel wall itself can be expected to reach the luminal surface of the vessel wall where they can influence endothelium and/or initiate deposition of blood elements on the vessel wall. Furthermore, the action of proteolytic enzymes on protein molecules such as zymogens might give rise to active substances not previously present.

Animals↗
PubMed1975

An epizootic of necrotic dermatitis in laboratory mice caused by Lancefield group G streptococci.

During a 7-mo period, mice from a group of 383 being used in a toxicology experiment developed severe progressive necrotic dermatitis, and some animals developed paralysis. The overall mortality rate for the group was 134/383 (35%). Seventeen mice were necropsied for bacteriologic and histopathologic examination. A streptococcus identified as Lancefield group G was isolated from the skin lesions of 15 of the mice, from 8 of 9 throats cultured, from 4 of 8 spleens, and occasionally from other sites. It was thought that the infections were initiated and perpetuated by bites from mice carrying the streptococcus in their mouth and throats. Microscopic examination of affected skin revealed necrotic dermatitis characterized by epithelial ulceration with suppuration. The skin lesions were reproduced in 6 of 15 mice inoculated with the isolated streptococcus.

Animals↗
PubMed1975

The occurrence of Mycoplasma arthritidis in the throat and middle ear of rats with chronic respiratory disease.

Twenty-three rats with chronic respiratory disease were examined for the presence of Mycoplasma arthritidis in the throat and middle ear. Samples were taken at necropsy and swabbed onto an agar medium. Morphologically typical colonies were subcultured and identified serologically. All of the rats showed evidence histopathologically of chronic respiratory disease, and typical M pulmonis colonies were isolated from 21 of 23. M arthritidis was isolated from 7 (30=) of the middle ears and 3 (13%) of the throats, confirming a previous observation of the occurrence of this organism in the middle ear of rats and also indicating it can be present in the throat.

Animals↗
PubMedDate not supplied

T cell subsets in human colostrum.

Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population.

Antibodies, Monoclonal↗