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Biomedical subjects

K Webb

Publications and source records attributed to K Webb.

61 records · Page 4Linked to original sources

A pilot epidemiologic study of possible health effects associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin contaminations in Missouri.

In 1971, 2,3,7,8-tetrachlorodibenzodioxin (TCDD)-containing waste oils were sprayed for dust control on residential, recreational, and work areas in Missouri. In several of these areas, the magnitude and the extent of this environmental contamination were not known until late 1982 or 1983. In the first phase of the investigation, a group of persons considered to be at highest risk of exposure and an appropriate comparison group were selected from reviews of Health Effects Survey screening questionnaires. These persons received complete medical examinations and a series of laboratory tests focused on detecting presymptomatic effects in key target organ systems (i.e., hepatic, dermatologic, immunologic, and neurologic effects). Comparisons of these two groups did not produce any firm indications of increased disease prevalence directly related to the putative exposures; of significance is the fact that no cases of chloracne or porphyria cutanea tarda were seen. Nevertheless, no overall definitive conclusion should be based just on this initial pilot study. Insights were provided that are being examined in more refined epidemiologic studies using different designs and strategies--especially of larger, more homogeneous population groups in which exposure status can be better characterized--focused primarily on discerning any potential effects on the urinary tract, liver, neurological, and immune systems. Concurrently, research into the development of replicable laboratory analytical methods and reference ranges for measuring TCDD body burden are being pursued.

Adolescent↗

New techniques for changing compliance in diabetes.

The low compliance by diabetic patients to professional recommendations is a major therapeutic challenge today. Patient education programs have been promoted as a remedy, but those developed to date need careful evaluation to see if they change health behavior. The knowledge-action gap has been well demonstrated in a number of chronic disorders. The early evaluation of our program in Sydney indicates that the educational intervention does change health behavior, especially in the difficult area of dietary compliance. This paper describes the evolution and the essential characteristics of the program. On completing the course, the diabetic patient is encouraged to use the home measurement of blood glucose by Eyetone meter to continue self-evaluation of control and monitor the effect of his compliance.

Attitude of Health Personnel↗

Effect of pheochromocytoma and hypophysectomy on blood pressure and catecholamines in NEDH rats.

The New England Deaconess Hospital (NEDH) rat provides a valuable model with which to study pheochromocytoma (P); 59% of male rats 700 to 900 days old and 81% of those 900 days or older developed spontaneous P. One transplantable P (P259), when implanted into other NEDH rats, markedly increased plasma norepinephrine and dopamine as well as blood pressure, and usually caused death within 4 weeks. Even without P, about 83% of NEDH rats became hypertensive by 131/2 weeks of age and remained moderately hypertensive until 2 years of age when some animals developed spontaneous P and hypertension became severe. Whether a common mechanism is responsible for early appearance of hypertension and later development of P remains to be determined. Hypophysectomized NEDH rats remained normotensive or slightly hypotensive despite marked elevations of plasma norepinephrine and dopamine caused by P259 implantation; furthermore, survival was prolonged to 3 months. Catecholamine concentrations in plasma and RBC were usually quite similar, indicating that red blood cells play a significant role in inactivating circulating catecholamines. Unlike the normal adrenal, P259 in NEDH rats contains mainly norepinephrine and dopamine with little epinephrine; it appears that P259 is deficient in the enzyme phenylethanolamine-N-methyltransferase (PNMT), which converts norepinephrine to epinephrine. Why hypophysectomy prevents hypertension and prolongs life in rats with P259 implants is unclear; adrenal cortical and thyroid deficiency may play a role. Preliminary observations indicate that hypophysectomy can prevent spontaneous development of P in NEDH rats.

Adrenal Gland Neoplasms↗