Indoor radon and lung cancer.

Fifty-four hourses, mostly in Bangkok and Nonthaburi, where 54 lung cancer patients had lived for same time were selected for investigating the presence of indoor radon by the charcoal canister method. In only four of these houses were radon level higher than the normal threshold level of 150 Bq.m (i.e. 153, 160, 172 and 283 Bq.m). Thus, the prevalence of elevated radon concentrations was a mere 7.40 percent in contrast with 22.16 percent found in the general survey. Although this finding would apparently suggest a negative relationship between indoor radon concentrations and lung cancer, it is possible that those patients had been exposed earlier to high radon concentrations, perhaps when the buildings were still new. It should be remembered also that exposure to even low radon concentrations dose not rule out the potential hazard of this radioactive gas as a cause of lung cancer. Most houses in this study (92.60%) were constructed of concrete and more than 5 years old. Therefore, it is not surprising to encounter such low radon levels, since rates are usually higher in newer buildings.

Adenosis Deaminase (ADA) activity in tuberculous and in carcinomatous lungs.

Determination of ADA activity in BALF was carried out in 12 patients with active pulmonary tuberculosis, 12 patients with bronchogenic carcinoma and 11 healthy volunteers. Pertinent findings were: (1) ADA activity increased significantly only in tuberculous lungs; and (2) ADA activity in diseased lungs was significantly higher than in apparently non-diseased lungs. The latter findings may reflect the difference in local cellular activity and proliferation rate between the diseased and non-diseased lungs.

The association of adenosine deaminase activity with T-lymphocytes and subsets in pulmonary tuberculosis and bronchogenic carcinoma.

Simultaneous determination of blood/lung ADA activity and T-lymphocyte subsets was conducted in 12 patients with active pulmonary tuberculosis, 12 patients with bronchogenic carcinoma and 11 healthy volunteers. Differences were significant only in the tuberculosis patients, namely, increased mean enzyme values in both the peripheral blood (36.68 +/- 10.90 U/L) and in the BALF (4.25 +/- 2.19 U/L), and correlation of ADA activity between the blood and the diseased lung only; the difference in elevated enzymatic activity between the tuberculosis group and the cancer group was of no statistical significance. We conclude that simultaneous ADA analysis of the blood and the BALF may be of diagnostic value in cases suspected of having tuberculosis as yet undiagnosed by other means. Based on the lowest value of enzymatic activity in the blood of patients with tuberculosis (28 U/L), the test has a sensitivity of 75 per cent and a specificity of 100 per cent; whereas the lowest value in the BALF of tuberculosis patients (2.9 U/L), the test has a sensitivity of 77 per cent and a specificity of 82 per cent. Findings that there was a blood-lung correlation of elevated ADA activity and a correlation of enzymatic elevation with increased numbers of T-cells bearing IL-2 receptor in cases of pulmonary tuberculosis only provide evidence in support of T-lymphocytes actively participating in the ongoing immune process.

Oxygen desaturation during fibreoptic bronchoscopy.

One hundred consecutive patients, who underwent bronchoscopic examination for diagnostic purposes, were studied with regard to various aspects of possible SaO2 deterioration. Relevant findings are as follows: (1) The pulse oximeter is as good as the conventional blood gas analyser for quantitating SaO2; (2) oxygen desaturation in the range of 1 to 25 per cent (median 5, mean 5.6 +/- 4) occurred in approximately 97 per cent of the bronchoscopy examinees; recuperation time of SaO2 was 1 to 34 minutes (median 6, mean 8.2 +/- 6.5); (3) the factor aggravating desaturation included the examination of patients in the sitting position; the fact that bronchial washing was connected with greater SaO2 deterioration in the non-hypoxaemic group of patients needs further investigation with regard to its role in the mechanism of oxygen desaturation; (4) the amount of fluid instilled intra-tracheally, bronchial biopsy and duration of the procedure were not related to the decline in SaO2. Based on the results of the present study, the authors suggest that all procedures ought to be performed on patients undergoing examination in the supine position, and that the patients should be supplemented with low-flow oxygen.

Bronchoalveolar T-lymphocytes and subsets in pulmonary tuberculosis and bronchogenic carcinoma.

Analysis of T-lymphocytes and their subsets in the blood and bronchoalveolar lavage fluids from 12 patients with active pulmonary tuberculosis, 12 patients with bronchogenic carcinoma and 11 healthy volunteers was aimed at identifying their immunologic functions and interrelationships. In patients with active pulmonary tuberculosis, there was a significant increased in the percentage of T-cells bearing IL-2 receptor both in the blood and bronchoalveolar lavage fluids, whereas patients with bronchogenic carcinoma exhibited an increase in the suppressor T-cells and T-cells bearing IL-2 receptor in the blood only. The presence of T-cells bearing IL-2 receptor is generally accepted to be the hallmark of recently active specific antigen activation of the helper T-lymphocytes together with monokine IL-1 stimulation. Suppressor T-cells, on the other hand, play a role in the immunopathogenesis of lung cancers and lung metastasis.