Five hundred and twenty tuberculosis patients admitted to hospital and having a high risk factor for human immunodeficiency virus (HIV) infection were evaluated for HIV seropositivity. Fourty patients (7.7%) were found to be seropositive. The clinical picture of these patients was compared with the seronegative tuberculosis patients. Extrapulmonary tuberculosis was more common in HIV seropositive patients. Weight loss and diarrhoea were more common in these patients but cough and haemoptysis were less frequent. Oral thrush and herpes zoster were seen only in HIV seropositive patients. The findings of this study show that HIV seropositive tuberculosis patients present with an atypical picture in this part of the country.

Polymerase chain reaction (PCR) for Mycobacterium tuberculosis was retrospectively analyzed in 101 suspected cases of tuberculosis to evaluate the role of PCR in the diagnosis of pulmonary and pleural tuberculosis. Of the 101 patients, bronchial wash specimens were obtained from 86 suspected pulmonary tuberculosis patients and pleural fluid from 15 cases of pleural effusion. The PCR was done using IS 6110 probe. Based on clinical, radiological, microbiological, histopatho-logical findings and/or past history of anti-tuberculosis treatment, suspected cases of pulmonary tuberculosis (n=86) were divided into four groups: i) active pulmonary tuberculosis (n:37), ii) old pulmonary tuberculosis (n:9), iii) sarcoidosis (n:6) and iv) other non-tuberculosis pulmonary diseases (n:34). The PCR results from bronchial wash specimens were compared with acid fast bacilli (AFB) smear results of bronchial wash specimens. The PCR was positive in 35 of 37 active pulmonary tuberculosis patients, all cases (n:9) of old pulmonary tuberculosis, all cases (n:6) of sarcoidosis and all cases (n:15) of pleural effusions. It was negative in all cases of non-tuberculosis pulmonary disease (n:34). Bronchial wash AFB smears were positive in 25 of 37 active pulmonary tuberculosis patients and were negative in all other groups. Thus the sensitivity of PCR in the diagnosis of pulmonary tuberculosis was 95% and the specificity was 69%. The low specificity of PCR highlights the high false positive rate. Therefore, PCR results have to be interpreted with caution in the diagnosis of pulmonary tuberculosis. However, PCR appears to be useful in the diagnosis of tuberculous pleural effusions.

Of the 200 patients who had histopathologically confirmed bronchogenic carcinoma during the period January 1990 to March 1996, 24 patients (12%) were found to be below 40 years of age in a tertiary Institute. Of the 24 cases, ten had adenocarcinoma, nine had squamous cell carcinoma, four had poorly differentiated carcinoma and one had large cell carcinoma. These 24 patients were randomly divided into two groups to evaluate the role of radiotherapy alone or radiotherapy with CMF (cyclophosphamide, methotrexate and fluorouracil) regime in the treatment of bronchogenic carcinoma in patients below 40 years. None of the patients in both groups had shown complete response to treatment on follow up. The mean duration of survival of the study subjects was seven months. Bronchogenic carcinoma in young adults, therefore, appears to be aggressive in nature and their response to treatment with radiotherapy and CMF regimen is poor.

The nasal mucociliary clearance (NMCC) was studied using the saccharin method in 100 patients of lower respiratory tract disorders which comprised of 11 patients of bronchiectasis, 35 of chronic bronchitis, 37 of bronchial asthma and 17 of pneumonia. The results were compared with 100 healthy controls. The nasal mucociliary clearance was significantly prolonged in bronchiectasis, chronic bronchitis and bronchial asthma but not in pneumonia. No relationship of nasal mucociliary clearance with duration of disease was observed. Whether this impairment is the cause or effect of the disease needs further elucidation.

Medical expert systems for diagnosis, treatment and management of diseases are gaining importance in the practice of modern medicine. Expert system is a program which uses artificial intelligence to provide solutions to difficult questions requiring specialized training to answer. Decision making in Intensive Care Unit (ICU), analysis of pulmonary function data, management of chronic diseases are some of the problems in the practice of respiratory medicine which will benefit from an unbiased guidance. Artificial neural networks, object oriented framework, fuzzy logic, genetic algorithm are some of the recent techniques used for the development of faster, efficient and reliable medical expert systems.

A 17 year old non-smoker male student, a known asthmatic since birth, presented with high grade fever, purulent non-foul smelling expectoration and breathlessness. Patient gave history of expectorating brownish plugs off and on in past. His father and maternal grand father were asthmatic. Chest auscultation revealed bilateral rhonchi and bronchial breathing with few crepitations in left infraclavicular region. His chest skiagram was as in Fig. 1. Total white blood counts were 13400 mm with 78% neutrophils, 12% lymphocytes and 10% eosinophils and erythrocyte sedimentation rate (ESR) was 44 mm 1st hr (Westergren). Sputum smears for acid fast bacilli were repeatedly negative.

Two cases of histopathologically confirmed primary leiomyoma of the lung are reported.