Effect of fly ash inhalation on biochemical and histomorphological changes in rat lungs.

Effect of respirable fly ash particles inhalation on lungs of rats was investigated by exposing them to respirable aerosols of size classified power plant fly ash at average concentrations of up to 14.4 +/- 1.77 mg/m3 for 4 hr/day for 28 consecutive days. A remarkable increase was found in blood eosinophil counts of fly ash exposed animals. Biochemical indicators of pulmonary damage viz. lactate dehydrogenase (cytoplasmic enzyme used as a measure of cell injury), gamma-glutamyl transferase (Clara cell damage) and alkaline phosphatase (potential measure of Type 11 cell secretions) in broncho alveolar lavage fluid (BALF) of fly ash exposed group showed significant elevation. Clumping of fly ash particles in the lungs was observed as evidenced by fly ash ladened macrophage accumulation in the alveolar region. The results suggest a damage, local inflammation and remodelling of lung as indicated by hypertrophy and hyperplasia. These changes reflect the toxic effects of the fly ash inhalation.

Effect of trichloroethylene (TCE) inhalation on biotransformation enzymes of rat lung and liver.

Trichloroethylene (TCE) is widely used as an industrial solvent and cleaning fluid. In the present study the toxic effects of TCE inhalation on pulmonary and hepatic biotransformation enzymes in rats have been investigated by assay of aniline hydroxylase (AH), aminopyrine-N-demethylase (APD), benzo-a-pyrene hydroxylase (BH) and glutathione-s-transferase (GST) activities and glutathione (GSH) contents in liver as well as lungs of exposed animals. In both organs phase I and phase II drug metabolizing enzymes have been found to be increased along with decrease in GSH contents following TCE inhalation. Pulmonary as well as hepatic MFO's seem to be activated by inhaled TCE probably in an attempt for its rapid detoxification and reduced glutathione is used during its biotransformation.

Evaluation of influenza virus detection by direct enzyme immunoassay (EIA) and conventional methods in asthmatic patients.

Throat gargle specimens of fifty-seven acute asthmatic patients (age range 18-40 years) were collected for the study. Thirty-four patients were found influenza virus positive in acute asthma cases. Influenza virus was isolated by conventional culture method on MDCK cell-line and by enzyme immunoassay test (EIA). The EIA negative specimens were retested after virus amplification on MDCK cell-line. Virus shedding and virus surface receptors assay was carried out to determine influenza virus titre. Airway functions were measured by spirometry. A good relationship was observed between the degree of airflow limitation and presence of influenza virus infection (p < 0.001; r = 0.85). A comparable difference in % FEV1 was observed in relation to the symptoms. The patients with greater viral antigen load had lower % FEV1. Two specimens, which were EIA negative, turned out to be positive after amplification on MDCK cell-line. The sensitivity was 98% and specificity was 100%. It was concluded that EIA method is a useful diagnostic tool as it detects influenza viral antigen quickly as compared to conventional methods.

Influence of influenza viral infection on airway smooth muscle activity.

The contractility of airway smooth muscle (ASM) plays an important role in pathophysiology of several bronchial disorders. Increased contraction of ASM during asthma and respiratory viral infection has been attributed to the release of mediators acting through different receptors. In the present study, influence of influenza type A virus (H1N1) infection has been examined on ASM responsiveness to various bronchoactive agents e.g. adenosine, histamine, 5-hydroxytryptamine (5-HT) and isoproterenol in an organ bath set up for isolated tissue preparation. The contractile effect of adenosine, histamine and 5-HT was enhanced, however, relaxant response of isoproterenol was attenuated with the duration following viral exposure. The most prominent response was observed 48 to 72 hr after infection and tissues from multiple exposure to virus infected animals showed the maximum contractile response. Results demonstrated the deleterious effect of viral infection on ASM function and the findings will be helpful in understanding the mechanism of influenza virus induced bronchoconstriction.

An outbreak of influenza A (H3N2) in Delhi, 1993.

An outbreak of Influenza A, subtype H3N2 occurred in Delhi during July-August, 1993. Both urban and rural areas were affected. Attack rates in children and adults were found to be similar; the mean age of patients from whom the virus was isolated was found to be 21 years. The disease was of acute onset, mild in nature and about one week in duration. Main symptoms included fever, chills, cough, sore throat, bodyaches, backache and headache. Complications were absent. About 82 per cent of the affected house-holds had only a single case. Influenza A subtype H3N2 virus was isolated from 12 of 15 throat swabs collected from PUO cases.

Radionuclide detection of gastroesophageal reflux in children suffering from recurrent lower respiratory tract infection.

Radionuclide gastro-esophageal scintigraphy was performed on 25 control and 183 children suffering from recurrent lower respiratory tract infection. Gastro-esophageal reflux (GER) of varying grades was observed in 135 patients. The severity of clinical symptoms in the patients was found to be directly related to the severity of reflux observed in the radionuclide study. In some patients an attempt was also made to quantitate GER by calculating the Gastro-esophageal reflux index. The results of the scintigraphic study were correlated with the results of the other commonly used and more conventional Barium swallow and fluoroscopy study. Gastro-esophageal scintigraphy was found to be much superior in terms of sensitivity, specificity and accuracy in detecting GER. It was also possible to objectively evaluate and monitor response to treatment following conservative or corrective surgical therapy using the radionuclide technique. The results of the study demonstrated a remarkably high incidence of GER in the patients. Whether GER is the cause of recurrent lower respiratory tract infection or not is difficult to establish firmly. But within the preview of the study the association seems to be very strong and cannot be easily ignored.

Evaluation of a new latex agglutination kit for detection of human rotavirus in faecal specimens.

A commercial latex agglutination (LA) test was compared with ELISA and direct electron microscopy (EM) for detection of rotavirus antigen in 93 stool specimens obtained from as many children with acute gastroenteritis. Seventy one specimens (76.3%) were either positive or negative with all the three techniques, while 22 (23.7%) gave contradictory results. Only 1 sample was positive by LA test but not with ELISA or EM. The sensitivity of LA test and EM was 62.5 per cent (30 of 48) and 75 per cent (36 of 48); the corresponding specificity being 97.7 per cent (44 of 45) and 100 per cent (45 of 45) respectively. ELISA was more sensitive than the LA test and EM for detection of rotavirus antigen. LA test which is highly specific and a rapid method, may be useful in certain situations but its low sensitivity makes it unsuitable for use in routine clinical practice.

Electrophoretic study of the genome of human rotavirus in rural Indian community.

A rural cohort of 507 children, less than 3 yr of age was kept under weekly surveillance for 12 months, for morbidity due to diarrhoea. Stool specimens for rotavirus detection were obtained in 346 of the 360 diarrheal episodes occurring in 354 children and in 211 children without diarrhoeal symptoms. Rotavirus was detected by an ELISA test in 4 per cent of children with diarrhoea and 6.6 per cent of control subjects. Viral genome RNA was extracted by phenol chloroform method from all the positive samples and analysed by polyacrylamide gel electrophoresis followed by silver staining. All the strains isolated, exhibited the same electropherotype with a 'long' RNA migration pattern. This result contrasts with the genomic variability amongst rotavirus strains usually observed in different settings.