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Biomedical subjects

M L Eaton

Publications and source records attributed to M L Eaton.

5 recordsLinked to original sources

Assessing differential drug effect.

The regression effect gives a misleading impression of the relationship between drug or treatment effect and baseline measurement. We propose a method of adjusting for the regression effect; we also suggest a corresponding test for the differential drug effect. The likelihood ratio test for no differential drug effect is equivalent to a test for equality of variances, suggested by Pitman (1939, Biometrika 31, 9-12) and Morgan (1939, Biometrika 31, 13-19). The proposed adjustment and test are applied to an example of blood pressure data.

Biometry

Isotretinoin in severe, recalcitrant cystic acne: a review.

Isotretinoin, an isomer of retinoic acid, recently has been approved by the Food and Drug Administration for treatment of severe, recalcitrant acne. The most impressive effects include inhibition of sebum production and a reversible decrease in sebaceous gland size. Isotretinoin has proved to be an effective drug; response to therapy has been seen in virtually 100 percent of patients treated. Almost all patients experience reversible cutaneous and mucous-membrane symptoms while on isotretinoin treatment. Other common side effects include conjunctivitis (38 percent) and eye irritation (50 percent). The recommended dosage is 1-2 mg/kg/d for no longer than 16 weeks. Isotretinoin is currently the treatment of choice for severe, recalcitrant acne; however, because of potential side effects associated with retinoids, isotretinoin should be reserved for those patients who are unresponsive to conventional therapy, including topical and systemic antibiotics.

Acne Vulgaris

Effects of theophylline on breathlessness and exercise tolerance in patients with chronic airflow obstruction.

Theophylline is commonly prescribed for patients with nonasthmatic chronic airflow obstruction (CAO) even though clinical efficacy is not well established. We studied objective and subjective responses to theophylline in 14 men with CAO. Subjects randomly received week-long treatments of placebo or theophylline at two dosages: one that produced low (8.7-13.0 micrograms/ml) and the other high (16.0-23.6 micrograms/ml plasma concentrations. During the final three days of each treatment, we measured spirometric and hemodynamic function. Exercise tolerance was assessed with the 12 minute walk and progressive cycle ergometry. The patients' perception of breathlessness during the usual activities of daily living was evaluated with the oxygen cost diagram and the breathlessness rating. For low and high dose theophylline there were significant (p less than .05) increases in forced vital capacity (7.1 +/- 2.1 percent; 12.0 +/- 1.7 percent), forced expiratory volume at one second (14.6 +/- 4.9 percent; 12.1 +/- 3.3 percent) and in pulse rate (8.3 +/- 1.2 percent; 19.1 +/- 3.1 percent), but no changes in blood pressure. There were also no significant differences among the three treatments for any of the tests which assessed exercise tolerance or breathlessness. These results suggest that most patients with CAO experience little symptomatic benefit from taking theophylline.

Adult

Chronic hypervitaminosis A.

A case of chronic hypervitaminosis A in a 51-year-old female is discussed. The patient was ingesting 27,500--35,000 international units of vitamin A daily for 30 years. The patient displayed the classic symptoms of the disease, including skin and hair changes, esophageal varices and extensive liver disease. Vitamin A products were discontinued and the patient's dietary intake of the vitamin was minimized. Previous reports and studies of hypervitaminosis A are reviewed. Social factors causing increased consumption of vitamin A and regulations governing the sale of vitamin A are discussed. By being aware of the factors influencing vitamin A consumption, hypervitaminosis A can be detected and prevented more readily.

Chronic Disease