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Biomedical subjects

D Williamson

Publications and source records attributed to D Williamson.

At least 109 records · Page 6Linked to original sources
PubMed1978

The diagnosis of microscopic carcinoma of the esophagus.

Microscopic squamous cell carcinoma of the esophagus with early submucosal spread was diagnosed in two patients with hiatal hernia and evidence of esophageal reflux. The lesions were not suggestive of malignancy on endoscopic examination. Both patients are known to be alive more than one year after resection and presumably without recurrence. More liberal use of endoscopic brush cytology and biopsy or intubation cytology particularly in the cases at high risk, might substantially improve the chances of very early diagnosis and favorably alter the present grim mortality rate.

Biopsy↗
PubMed1977

Enhancement of urethan tumorigenesis in mouse lung by butylated hydroxytoluene.

Intraperitoneal injection of the antioxidant butylated hydroxytoluene (BHT) produces cell proliferation in mouse lungs within 2-4 days. We examined whether the presence of an increased number of proliferating lung cells would influence urethan tumorigenesis. Male Swiss-Webster mice were treated with 1 mg urethan/g before, during, or after BHT-stimulated cell growth in the lung. The number of pulmonary tumors found 13-15 weeks later was not different in BHT-treated mice compared to that in controls. On the other hand, repeated stimulation of cell growth after urethan treatment enhanced tumorigenesis. Male Swiss-Webster and A/J mice were given a single dose of urethan (1 mg/g) and, beginning 7 days later, weekly injections of BHT or corn oil. Repeated injections of BHT significantly increased the yield of lung tumors in both strains. Weekly injections of BHT into mice pretreated with 0.9% NaCl reduced the number of spontaneous pulmonary adenomas.

Animals↗
PubMed1977

Praecordial ST segment elevation. New technique for continuous recording and analysis.

The measurement of praecordial ST segment elevation after myocardial infarction is of value in assessing the natural history of ischaemic injury and the effectiveness of intervention. Hand analysis is, however, time consuming and inaccurate. A technique for continuous recording from 35 praecordial leads and subsequent computer analysis is presented, together with illustrative case studies. Changes in body posture and in heart rate are of importance in subsequent data interpretation.

Adult↗
PubMed1976

Advancement to independent living: a model behavioral program for the intermediate care of adults with behavioral and emotional problems.

This article describes and evaluates the treatment effectiveness of a behaviorally oriented intermediate day-care clinic for adults with psychiatric disturbances. The goals of the program included reducing the number of psychiatric hospital admissions and readmissions, providing a community-based controlled environment to assist patients in the modification of specific problem behavior, improving interpersonal relations with "significant others" in the natural environment, teaching patients how to use community resources, and preparing them for employment and/or continued outpatient treatment. The program was structured so that patients advance through a series of four achievement levels for a variety of extrinsic and intrinsic reinforcers. While in the program, patients were introduced to available community resources, and were gradually phased into follow-up services. Results showed that 79% of all patients thus far treated partially, if not completely, advanced through the levels. There was also a high probability that a patient would advance from any given level. Outside-clinic behavior showed sustained improvement, with the authors concluding that the day-care clinic offered promise for the future.

Adult↗
PubMed1976

Biochemical paramters of BHT-induced cell growth in mouse lung.

Male mice of 7 different strains were injected i.p. with 400 mg/kg of butylated hydroxytoluene (BHT). 2 and 4 days later, the incorporation of thymidine into pulmonary DNA was significantly increased in all treated animals and this was accompanied by an increase in lung weight and pulmonary DNA. Thymidine kinase activity and DNA polymerase activity were enhanced in the lungs of BHT-treated animals and maximum activity of these enzymes appeared to precede maximum thymidine incorporation by 24 h. 3 days after BHT a good correlation was found between administered dose and thymidine kinase activity. Measuring the activity of this enzyme might serve as a convenient biochemical marker to follow and to quantitate BHT-produced cell proliferation in lung. The concentrations of cyclic AMP and the activity of adenylate cyclase were not altered by BHT on days 1-9 after administration. BHT produced also some dose-dependent, time-dependent increases in the activities of pulmonary 5'-nucleotidase and glucose-6-phosphate dehydrogenase (G6PDH), but had little effect on isocitric dehydrogenase (ICDH), pyruvate kinase (PK) and lactic dehydrogenase (LDH).

Animals↗
PubMed1975

An explanation fro chloracne -- an industrial hazard.

Patients with chloracne were investigated and the results compared with data matched for age and site from patients with acne vulgaris. The ultrastructural appearances of pilo-sebaceous ducts in both groups were similar. The industrial group had significantly fewer C. acnes than the patients with ordinary acne. They also showed a significant increase in the surface lipid percentage composition of squalene, wax ester and cholesterol and this was associated with a significant decrease in the triglyceride free fatty acids and total triglyceride pool. We suggest that the acnegenic agent has produced its effect by modifying the metabolism of the pilo-sebaceous fluid.

Acne Vulgaris↗
PubMedDate not supplied

The correspondence between coronary heart disease mortality and risk factor prevalence among states in the United States, 1991-1992.

OBJECTIVE: This study aimed to examine the correspondence between seven established risk factors for coronary heart disease (CHD) and CHD mortality among the states in the United States. An ecologic analysis relating CHD risk factor prevalences to CHD mortality rates among 49 states was undertaken in 1991-1992. METHODS: Approximately 68,000 men and women ages 45-74 were randomly sampled and interviewed by telephone in surveys conducted in 49 states in 1991 and 1992. From these interviews, we estimated state-specific prevalences of smoking, overweight, physical inactivity, hypertension, elevated cholesterol, diabetes, and alcohol abstinence. These seven CHD risk factors were also combined to create a CHD risk index for each state. The main outcome measures were mortality rates from CHD (ICD9 codes 410.0-414.9) in each of 49 states in 1991-1992 for men and women ages 45-74. The analysis was based on multiple linear regression and Spearman's rank-order correlations between the CHD risk factor prevalences, the combined CHD risk index, and the CHD mortality rates among the 49 states. RESULTS: The prevalences of most of the CHD risk factors correlated with CHD mortality rates in the expected directions, and correlations were similar for men and women. The CHD risk index correlated strongly with CHD mortality for both men (r = 0.75) and women (r = 0.80). CONCLUSION: About 60% of the variance in CHD mortality between the states in the United States (56% for men and 64% for women) is attributable to differences between the states in the prevalences of seven established risk factors for CHD. As state health agencies prioritize resources for chronic disease prevention programs, they should consider the potential benefits of increased efforts to reduce the prevalences of modifiable CHD risk factors in their populations to reduce CHD mortality.

Aged↗
PubMedDate not supplied

Antimalarial activity of rifampicin in vitro and in rodent models.

The antimalarial activity of rifampicin, a specific inhibitor of bacterial ribonucleic acid (RNA) polymerase, was confirmed with Plasmodium falciparum in vitro and with P. chabaudi in vivo. The viability of ring forms of P. falciparum, measured by [3H]hypoxanthine and [14C]isoleucine uptake, was significantly reduced within 5 h of exposure to 2.5 microM rifampicin, the 50% inhibitory concentration. Streptolydigin and tagetitoxin, other specific inhibitors of bacterial RNA polymerase, were much less effective as antimalarials. A rifampicin-tolerant sub-line of P. falciparum was selected in vitro. When released from drug pressure, the tolerant line showed appreciably greater rates of incorporation of precursors and growth than the parent line, but over a period of months these characteristics gradually reverted. Rifampicin was effective against a chloroquine-resistant line of P. falciparum and the rifampicin-tolerant line had increased chloroquine sensitivity. Treatment of patent parasitaemias of P. chabaudi in mice with more than 100 mg/kg rifampicin twice daily significantly reduced the parasitaemia within 24 h and parasites were barely detectable on blood films by the fourth day. Recrudescence occurred on release of drug pressure.

Aminoglycosides↗