The utility of gram stain and semiquantitative culture of the fluid retrieved by bronchoalveolar lavage (BAL) in identifying the causative agent in acute bacterial pneumonia was initially assessed in 92 patients. Fifteen of these patients presented with clinically active bacterial pneumonia; the remaining patients underwent bronchoscopy to evaluate other processes in the lung. Thirteen of the 15 patients with clinically active bacterial pneumonia had a BAL culture greater than or equal to 10(5) colony-forming units per milliliter of BAL fluid, whereas none of the other groups had a positive culture (chi 2 = 70.7, P less than .001). Gram stain of cytocentrifuged BAL fluid was positive (one or more organisms seen per 1,000 X field) only in those patients with an active bacterial pneumonia. Applying this technique, we studied 59 immunocompromised patients presenting with pulmonary infiltrates. Eight (21%) of the 39 patients presenting with microbial-related infiltrates proved to have acute bacterial pneumonia by BAL culture; the pneumonia resolved with appropriate antimicrobial therapy.

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Thyroid nodularity following continuous low-dose radiation exposure in China was determined in 1,001 women aged 50-65 years who resided in areas of high background radiation (330 mR/yr) their entire lives, and in 1,005 comparison subjects exposed to normal levels of radiation (114 mR/yr). Cumulative doses to the thyroid were estimated to be of the order of 14 cGy and 5 cGy, respectively. Personal interviews and physical examinations were conducted, and measurements were made of serum thyroid hormone levels, urinary iodine concentrations, and chromosome aberrations in circulating lymphocytes. For all nodular disease, the prevalences in the high background and control areas were 9.5% and 9.3%, respectively. For single nodules, the prevalences were 7.4% in the high background area and 6.6% in the control area (prevalence ratio = 1.13; 95% confidence interval = 0.82-1.55). There were no differences found in serum levels of thyroid hormones. Women in the high background region, however, had significantly lower concentrations of urinary iodine and significantly higher frequencies of stable and unstable chromosome aberrations. Increased intake of allium vegetables such as garlic and onions was associated with a decreased risk of nodular disease, which seems consistent with experimental studies suggesting that allium compounds can inhibit tumor growth and proliferation. The prevalence of mild diffuse goiter was higher in the high background radiation region, perhaps related to a low dietary intake of iodine. These data suggest that continuous exposure to low-level radiation throughout life is unlikely to appreciably increase the risk of thyroid cancer. However, such exposure may cause chromosomal damage.