Regression equations for spirometry in children aged 6 to 17 years in Delhi region.

Background. Most of the studies carried out in India to develop regression equations for spirometry in children are now several years-to-decades old and had used equipment and measurement protocols that have since changed. Prediction equations using the current standardisation protocols for spirometry are not available. The lung health of the population may have changed too. Objective. To develop regression equations for spirometry for children aged 6 to 17 years of north Indian origin in Delhi region. Methods. School children of north Indian origin, as determined by mother tongue and parentage, aged 6 to 17 years were screened by a health questionnaire and physical examination and those found “normal” underwent spirometry according to the standardised procedure recommended by the American Thoracic Society/ European Respiratory Society (ATS/ERS) task force in 2005. Pearson’s correlation analysis was carried out to identify the predictor variables for spirometric parameters. Prediction equations were developed using the multiple linear regression procedure. The independent variables were entered in sequence of height, age and weight. R2, adjusted R2 and R2 change, standard errors of the estimate (SEE), and estimates of regression coefficients were obtained and the goodness of fit was examined. Results. Data was obtained in 365 boys and 305 girls. Forced vital capacity (FVC), forced expiratory volume in one second(FEV1), peak expiratory flow rate (PEFR), forced expiratory flow rate at 50% and 75% exhalation of vial capacity (F50 and F75) and mean forced expiratory flow rate over the middle 50% of the vital capacity (F25-75) showed moderate to strong correlations with age, height and weight in both boys and girls. In both genders, the equations explained very high variability of FVC, FEV1 and PEFR as shown by the R2 values. The explained variability for flow rates was lesser, with that for F75 being the least. Conclusions. Regression equations for spirometry variables for children of north Indian origin in Delhi region have been developed. These represent the first such effort from India after the publication of the ATS/ERS task force 2005 guidelines on standardisation of spirometry.

Investigation of the effects of extracts of Manilkara zapota (L.) P. van Royen on blood pressure and heart rate of rats

The objective of the study was to investigate the hypotensive effect produced by leaf extracts of Manilkara zapota. Methanol extracts of Manilkara zapota leaves were prepared using a soxhlet apparatus. The methanol was removed with a rotor evaporator. Sprague-Dawley rats were anaesthetized with urethane (1.2 mg/kb) and doses of 0.63, 1.25, 2.5, 5.0, 10.0 and 20.0 mg/kg body weight of extract were administered intavenously. Saline (0.9 percent) was given as a control. The effects on blood pressure and heart rate were recorded using a Pressure transducer (Spectramed model 23XL) coupled to a Grass polygraph (model 79E). The plant extract showed a dose-related hypotensive activity and no significant change in heart rate (P.0.05). Toxicity was observed with doses greater than 20mg/kg body weight. These results indicate that Manilkara zapota leaf tea used in folklore medicine to treat hypertension does indeed show various degrees of hypotensive activity when tested in lab animals. However, larger doses were toxic. It is therefore necessary to assess the beneficial as well as the adverse effects of this herb before usage by the hypertensive patient