Apparent resistance to fall in forced vital capacity in children with increasing mass level of fine particulate: A physiological phenomenon

Abstract

Forced vital capacity (FVC) of children in the age group 10–12 years are reported as a function of quantum increase in PM_2.5 level in ambient air. The data are reported for the children in the categories based on their respective body mass index (BMI). FVC (% predicted) values decreased with increasing level of PM_2.5. The subjects are found to respond in a selective manner as plateau was observed for FVC values against some selected ranges of PM_2.5 concentration levels (74 µgm^?3 to >117 µgm^?3). To explain this unusual behavior, sac theory is proposed which explains the observations of FVC for subjects of all categories with different BMI values.     

Altered hemolysin production in urine-grown uroisolates ofEscherichia coli

Fifteen uroisolates ofE. coli were studies for both cell-free and cell-bound hemolysin production. Estimations were done inTrypticase soy broth (TSB, providing iron-replete medium) TSB +2,2′-bipyridine (providing experimentally created iron-depleted conditions) and pooled normal human urine (providing natural iron-depleted growth medium). In TSB 40% of strains showed no detectable cell-free hemolysin, they were able to produce it in the presence of 2,2′-bipyridine and more so when grown in urine. The cell-bound hemolysin was produced by all the strains in TSB, but in the presence of 2,2′-bipyridine and urine an insignificant increase was observed. All the strains when given 2nd and 3rd passage in urine, were found to elaborate significantly more cell-free as well as cell-bound hemolysin.