The characterization of mutant Bacillus subtilis adenylosuccinate lyases corresponding to severe human adenylosuccinate lyase deficiencies.

Adenylosuccinate lyase is a homotetramer that catalyzes two discrete reactions in the de novo synthesis of purines: the cleavage of adenylosuccinate and succinylaminoimidazole carboxamide ribotide (SAICAR). Several point mutations in the gene encoding the enzyme have been implicated in human disease. Bacillus subtilis adenylosuccinate lyase was used as a model system in which mutations were constructed corresponding to those mutations associated with severe human adenylosuccinate lyase deficiency.

The spectrum of tuberculosis in a New York City men's shelter clinic (1982-1988).

The objective of this study was to determine the prevalence of tuberculous infection and the incidence of active tuberculosis in homeless men attending a shelter-based clinic and to examine risk factors for acquisition of infection and development of active disease. The design was a prospective cross-sectional survey. Men were evaluated by standardized interviews using a questionnaire.

Early predictors of in-hospital mortality for Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome.

One hundred forty-five patients were initially seen with Pneumocystis carinii pneumonia (PCP). Of the many features examined, several variables were identified early in the hospitalization for PCP that were associated with poor survival. These included multiple admissions, leukocytoses, elevated serum lactate dehydrogenase levels, decreased arterial oxygen pressure (tension), decreased arterial carbon dioxide pressure (tension), and decreased serum albumin levels.

Further observations on tuberculin reactions in active tuberculosis.

One hundred patients with active tuberculosis were tested for tuberculin reactivity within 24 hours of their admission to the hospital. Commercial intermediate tuberculin, Tween stabilized intermediate tuberculin and the Tine test as well as a mumps antigen were applied simultaneously. False negative reactions were obtained in 28 per cent with Tine testing and in 21 per cent with Tween stabilized as well as plain tuberculin.

A computer-assisted instruction course in the diagnosis and treatment of respiratory diseases.

A computer-assisted simulation of the 'chart method' of teaching has been developed and was used to provide instruction in clinical decision-making in the diagonosis and treatment of pulmonary diseases. The course requires a student to reach and to defend a diagonisis and to provide appropriate treatment for each of 10 simulated cases. Evaluation of performance and immediate feedback and correction of errors of commission and ommission are an integral part of the course.