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Biomedical subjects

S Davis

Publications and source records attributed to S Davis.

At least 397 records · Page 22Linked to original sources
PubMed1986

Platelet activation during exercise induced asthma: effect of prophylaxis with cromoglycate and salbutamol.

Peak expiratory flow (PEF) and plasma concentrations of platelet factor 4 and beta thromboglobulin were measured before and after exercise in nine asthmatic patients and 12 non-asthmatic volunteers. Exercise was preceded by administration in random order of either placebo, salbutamol 200 micrograms, or sodium cromoglycate 2 mg from a pressurised inhaler. In control subjects there were minimal changes in PEF and plasma concentrations of platelet factor 4 and beta thromboglobulin. In the asthmatic patients the typical changes in PEF were seen on exercise; plasma concentrations of platelet factor 4 and beta thromboglobulin rose significantly in parallel, the rise preceding the fall in PEF. The changes in peak flow and platelet activation induced by exercise were attenuated by prior administration of salbutamol or cromoglycate. These results indicate that exercise induced asthma is associated with a rise in platelet release products similar to that observed in antigen induced asthma.

Adult↗
PubMed1986

Immunological studies in patients with alcoholic liver disease: evidence for the in vivo activation of helper T cells and of the monocyte-macrophage system.

Immunologic parameters were evaluated in 22 patients with alcoholic liver disease (ALD). Patients with ALD had increased levels of circulating immune complexes (CIC) and serum immunoglobulins, particularly IgA. The classical complement pathway was preferentially activated in CIC-positive patients. There was no increase in total lymphocyte or total T lymphocyte counts, but a significant rise in both the helper/inducer population (OKT4) and helper/suppressor cell ratio (T4/T8) was noted. The presence of interleukin-2 receptors and HLA-DC/DS and HLA-DR antigens suggested in vivo activation of ALD patients' T cells. The rate of differentiation of B cells to plasma cells was high in both pokeweed mitogen-stimulated and unstimulated cultures of ALD patients' B cells, whereas plasma cell generation doubled when patient T lymphocytes were added to enriched normal B cells. The above data support a role for activated helper (T4+) T cells in the immune response initiated by alcoholic hepatitis. Serum angiotensin-converting enzyme levels and lysozyme levels were increased in ALD patients, and cultured adherent mononuclear cells from ALD patients secreted more lysozyme in vitro than normal cells, suggesting the presence of an activated monocyte-macrophage system in ALD.

Adult↗
PubMed1986

Incremental dynamic computed tomography: practical method of imaging the carotid bifurcation.

A simple, practical method of applying incremental dynamic computed tomography (CT) to the imaging of 20 carotid bifurcations is described. The results are compared with those obtained by conventional carotid angiography and intravenous digital subtraction angiography (DSA). Conventional angiography provided additional information about the carotid bifurcation in only one of 14 cases, while incremental dynamic CT provided information not available from intravenous DSA in two of eight cases. Conventional brain CT is being used increasingly in the workup of patients with transient ischemic symptoms, and dynamic CT scanning at 3-mm increments requires only an extra 5 min of scanner time. The addition of incremental dynamic CT through the carotid bifurcation to the conventional brain CT scan procedure may obviate other screening tests before more definitive angiographic procedures.

Carotid Artery Diseases↗
PubMed1986

A population-based study of lung cancer incidence trends by histologic type, 1974-81.

All incident cases of microscopically confirmed lung cancer diagnosed between 1974 and 1981 in western Washington State were identified through the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, Bethesda, MD. The incidence of lung cancer by histologic type was studied in relation to time, with age, sex, and stage of disease at diagnosis being taken into account. Overall and within each sex, the incidence of adenocarcinoma has increased significantly since 1974. The rate of increase has been higher among females (86% increase) than among males (54% increase), with most of the increase in both sexes being among those over age 65 years with distant or unstaged disease at diagnosis. Similar patterns were not observed for squamous cell carcinoma. The potential effects of changes in diagnostic and pathology practice during the study period in producing these results were explored, and etiologic implications of the observed increase in adenocarcinoma were discussed.

Adenocarcinoma↗
PubMed1985

The epidemiology of drowning in Cape Town--1980-1983.

The results of a 4-year retrospective study on the epidemiology of drowning in greater Cape Town are presented. With rates corrected to per 100 000 population, the highest incidences of drowning were found to be in white children and adult black males. The commonest sites of drowning were the coastline and harbours of greater Cape Town. The majority of adult drownings were associated with positive blood alcohol tests (64,6%) and in the case of black men occurred while at work. The majority of drownings in children occurred in home swimming pools.

Accidents↗
PubMed1985

Mitochondrial and plasma membrane potentials cause unusual accumulation and retention of rhodamine 123 by human breast adenocarcinoma-derived MCF-7 cells.

Quantitative studies of MCF-7 cells (derived from human breast adenocarcinoma) and CV-1 cells (from normal African green monkey kidney epithelium), using the permeant cationic compound tetraphenylphosphonium (TPP), in conjunction with fluorescence microscopy using rhodamine 123 (Rh123), indicate that the mitochondrial and plasma membrane potentials affect both uptake and retention of these compounds. Under conditions that depolarize the plasma membrane, uptake and retention of TPP and Rh123, driven only by the mitochondrial membrane potential, is greater in MCF-7 than in CV-1. An ionophore that dissipates the mitochondrial membrane potential of MCF-7 cells causes them to resemble CV-1 cells by decreasing uptake and retention. Hyperpolarizing the mitochondrial membrane of CV-1 increases accumulation and prolongs retention; hyperpolarization of the plasma membrane further heightens this effect, causing the uptake of CV-1 cells to resemble that of MCF-7 cells even more closely. The greater uptake and retention by MCF-7 appears to be a consequence of elevated mitochondrial and plasma membrane potentials. The plasma membrane potential affects mitochondrial retention of TPP and Rh123 and its role in enhancing the effect of a difference in mitochondrial membrane potential is explained.

Adenocarcinoma↗
PubMed1985

Participants in prospective, randomized clinical trials for resected non-small cell lung cancer have improved survival compared with nonparticipants in such trials.

The survival of 78 patients with resected non-small cell lung cancer entered in prospective, randomized investigational trials is compared to that of a population-based group of control patients not included in such trials. The survival of trial patients is significantly better than that of controls (P less than 0.001). This survival advantage for trial participants is most apparent among late Stage I patients, and is observed after matching for known prognostic factors (i.e., primary tumor size, nodal status, tumor histology) and after adjusting in the analysis for age, sex, and the administration of radiation therapy. Several explanations for the improved outcome for trial patients are explored, including differences in preoperative evaluation, staging, surgical technique, placebo effects, and patient motivation. These results suggest the possibility that inclusion in these controlled cancer trials may have had an inherent advantage for all participants.

Adult↗
PubMed1985

Long-term survival in small-cell carcinoma of the lung: a population experience.

Small-cell lung carcinoma (SCLC) is a rapidly progressive and fatal disease. Historically, surgical resection or radiotherapy of the primary tumor has done little to prolong survival, although the use of combination chemotherapy is more effective. Reported here is the survival experience of 1,538 incident cases of SCLC identified through the Surveillance, Epidemiology and End Results Program in western Washington State from 1974 to 1982. The survival experience of this population series is similar to that reported from specialized referral centers. For 71 of 78 persons surviving at least 24 months, the original diagnostic slides were independently reviewed, 47 cases being confirmed as SCLC. No differences were found in actuarial survival estimates between those confirmed and those not confirmed as SCLC. Multivariate survival analysis was conducted to estimate the effects on survival of stage, therapy, age, sex, primary site, and histologic type. All factors except primary site and histologic type significantly influence initial survival rates. However, the only factor related to post--two-year (ie, long-term) survival, once stage is accounted for, is whether surgery was received as a first course of therapy. Those not receiving surgery were at four times the risk of death as those who did. These results indicate that long-term survival can be achieved in patients with SCLC treated in the community, and that the chance of surviving an additional two years for such patients is approximately 40%.

Adult↗
PubMed1985

Drownings of children and youth in a desert state.

Despite the fact that New Mexico is a desert state, the drowning rate (4.3) is 40% higher than that nationally (3.0). More than half of those who drown are younger than 25 years, toddlers and adolescents being at greater risk than other age groups. In an epidemiologic study of a six-year period, male drowning victims outnumbered female and American Indian and Hispanic victims outnumbered whites. Other major risk factors were epilepsy, mental retardation and alcohol abuse. In most drownings in the under-25 age group, the victim was involved in recreation near the water or swimming, although many were partially or fully clothed. Most drownings occurred in lakes, ditches or rivers. Because New Mexico is not a water-oriented state, public awareness of drowning hazards needs to be increased and more intensive preventive efforts instituted.

Adolescent↗