Development of a knowledge test in the science of prevention of lung diseases.

We developed a 50-item multiple choice test to assess knowledge of preventive pulmonary medicine. We derived the content of test items from a comprehensive preventive pulmonary curriculum, which we developed. The test was administered to 167 medical students, residents, and practicing physicians to establish its psychometric properties and to determine if the test scores discriminated between different levels of training. Using this sample, the reliability of the test was 0.86, and the test significantly differentiated between levels of training in pulmonary medicine. We are using this multiple choice test to assess changes in knowledge of second-year medical students and of fourth-year medical students completing a pulmonary medicine elective rotation.

Chronic and recurrent pneumonia.

Recurrent pneumonia is defined as two or (usually) more separate episodes of lower respiratory tract infection that generally are accompanied by fever, leucocytosis, and purulent sputum production. These episodes are separated by an asymptomatic interval of at least 1 month or clearing of the chest visible by radiograph. Clinical improvement and radiological clearing should result after appropriate antimicrobial therapy. Chronic pneumonia is an illness that lasts at least 6 weeks and is caused by a microorganism. The chest radiograph usually shows diffuse or focal shadows. The incidence of either chronic or recurrent chest infections is unknown. Neither condition is common, but when present, they frequently present a difficult diagnostic challenge. Chronic pneumonias are usually caused by slow-growing organisms, such as fungi or mycobacteria. Occasionally, chronic pneumonias cannot be diagnosed, even when lung biopsy specimens are cultured or studied histopathologically. When a patient presents with recurrent pulmonary parenchymal infections, the clinician needs to identify the likely etiologies. Possible etiologies are structural abnormalities, underlying medical conditions, and immunological abnormalities, including infection by the human immunodeficiency virus (HIV).

Short-term regulation of fatty acid synthesis in isolated alveolar type II cells from adult rat lung. Effects of free fatty acids and hormones.

We measured the total rate of fatty acid synthesis in alveolar type II cells freshly isolated from the lungs of adult rats. The rate of incorporation of 3H from 3H2O into cellular fatty acids was linear during 3-hr incubations and was very brisk [18 ng-atoms 3H/10(6) cells/hr +/- 2 (mean +/- SD, n = 23)]. When the nutrient medium (Minimum Essential Medium) was supplemented with various hormones or free fatty acids, the long-chain fatty acids (C14-C20) caused a decrease in the rate of 3H incorporation to a variable degree depending on the species of fatty acid. Stearate (10(-4) M) and palmitate (10(-4) M) caused the greatest inhibition of de novo cellular fatty acid synthesis, followed by myristate, arachidonate, and oleate. Insulin (10(-7) M), glucagon (10(-8) M), terbutaline (10(-5) M), 8-bromo-cyclic AMP (10(-3) M), the essential fatty acid linoleate (10(-4) M), and the medium-chain-free fatty acids laurate and octanoate (10(-4) M) did not alter the rate of fatty acid synthesis in type II cells. We demonstrated that the alveolar type II cell is a major lipogenic cell type in the rat. We also demonstrated that the availability of preformed fatty acids in the extracellular milieu is one factor regulating the rate of fatty acid synthesis in these cells.

Metabolic properties and ultrastructure of alveolar type II cells isolated with elastase.

We used porcine pancreatic elastase to isolate type II cells from the lungs of rats; the yield and purity of the type II cells was better than that obtained by methods using trypsin. In 102 experiments we obtained 82 +/- 23 . 10(6) cells/rat, 68 +/- 11% (mean +/- S.D.) of which type II cells. This preparation of cells, when centrifuged over a discontinuous density gradient, yielded 25 +/- 10 . 10(6) cells/rat, 80 +/- 13% of which were type II cells (n = 102). The cells, after density gradient centrifugation, could be futher purified by centrifugal elutriation (94 +/- 3% type II cells, n = 22) or adherence in primary culture (94 +/- 2% type II cells, n = 34). Type II cells isolated with elastase are similar morphologically and biochemically to type II cells isolated from rats with trypsin. The preparations of cells appeared healthy by several different criteria: ultrastructure, exclusion of vital dye, lack of stimulation of oxygen consumption by exogenous sodium succinate, and linear rates of oxidation of [1-14C]palmitic acid and of incorporation of [1-14C]acetate into fatty acids. Type II cells consumed 75 +/- 20 nmol O2/10(6) cell per h, oxidized [1-14C]palmitic acid at a rate of 0.4 nmol/10(6) cells per h, and incorporated [1-14C]acetate into fatty acids at a rate of 7.5 nmol/10(6) cells per h.

The pathogenesis of pulmonary and miliary tuberculosis.

Tuberculosis is spread from human to human by airborne transmission; it is not a highly infectious disease. Primary infection remits in 90% of cases and is progressive in the remainder; it is accompanied by lymphohematogenous seeding of many organs, and reactivation may occur as early as three months or many years after initial infection. Primary infection generally confers immunity from subsequent reinfection. The risk of reactivation of tuberculosis is greatest in the year after infection, declining sharply thereafter for most patients. Acute miliary tuberculosis has a distinctive pathogenesis that is different from localized postprimary disease. Miliary tuberculosis may appear in a patient with a normal chest roentgenogram; even in patients with abnormal chest roentgenograms, sputum cultures for acid-fast organisms may be negative. Transbronchial biopsy is the preferred method of diagnosis and prompt initiation of treatment is essential.

Public health and preventive aspects of pulmonary tuberculosis. Infectiousness, epidemiology, risk factors, classification, and preventive therapy.

Tuberculosis is usually of a low order of infectivity. Once treatment has begun, patients are no longer infectious to close contacts, and there is no benefit to isolating them. Among the risk factors associated with tuberculosis that reactivates after many years of dormant infection, the coexistence of silicosis, diabetes mellitus, and the postgastrectomy state with tuberculosis are reasonably well demonstrated. Preventive treatment begins with prompt institution of chemotherapy in the index case. Isoniazid is extremely effective in preventing tuberculosis infection from becoming tuberculosis disease. The benefits of BCG vaccine are controversial, and it is little used in the United States. Hepatotoxicity is a potential serious side effect of isoniazid chemoprophylaxis. Clinical monitoring for prodromal symptoms makes the drug safe and effective for patients under 35 years of age.

An investigation of the mechanism of ethanol-induced bronchoconstriction.

A 28-year-old Asian-American woman complained of symptoms of acute bronchoconstriction after drinking alcohol beverages. We documented the presence of ethanol-induced bronchoconstriction in this patient by administering oral ethanol challenges under controlled conditions. Bronchoconstriction was not prevented by pretreatment with atropine sulfate or cromolyn, suggesting that neither cholinergic postganglionic pathways nor mediator release from mast cells was the cause of the acute airway narrowing. The rapid decrease in specific airway conductance after ethanol ingestion and the association with symptoms of vasomotor sensitivity suggest that ethanol may have acted in this patient by releasing one or more secondary mediators with vasoactive and bronchoactive properties.