Concentration of nitrite in respirable particulate matter of ambient air in Vadodara, Gujarat, India.

Water extract of respirable particulate matter (RPM) was analyzed by Ion chromatography technique to investigate the presence of nitrite (NO2) as secondary aerosol in ambient environment. The nitrite particulates undergo photo hydroxyl radical reaction in environment produce nitrous acid, which reacts with metal and absorbs on RPM as water-soluble metal salt. The mean concentration of nitrite was 20.86 microg m(-3) in ambient environment. Regression analysis showed that the relationship for respirable particulate matter and nitrite (RPM-NO2, R2 = 0.742) was positively significant. We are reporting the presence of nitrite as an aerosol in ambient environment.

Environmental monitoring of benzene and toluene produced in indoor air due to combustion of solid biomass fuels.

Exposure to benzene and toluene from the combustion of solid biomass fuels is one of the important causes of morbidity and mortality in developing countries. In this study, we assessed the exposure of cooks to benzene and toluene from biomass fuel combustion in 55 rural homes. The GC-MS was used for quantification while a personnel sampler was used for environmental monitoring. The benzene exposure differed significantly (p < 0.0001) across different types of indoor kitchen fuel combinations. The geometrical mean (GM) of benzene exposure for cooks during cooking hours in an indoor kitchen using mixed fuel was 75.3 microg/m3 (with partition) and 63.206 microg/m3 (without partition), while the exposure was 11.7 microg/m3 for open type. The benzene exposure was significantly higher (p < 0.05) in an indoor kitchen with respect to open type using mixed fuels. Concentration of benzene (114.1 microg/m3) for cooks in an indoor kitchen with partition using dung fuel was significantly higher in comparison to non-cooks (5.1 microg/m3) for open type. Benzene exposure was not significantly different for kitchen with ventilation (31.2 microg/m3) and without ventilation (45.0 microg/m3) using wood fuel. However, this value was significantly (p < 0.05) lower than in indoor kitchens with or without partition. An almost similar trend was observed for toluene but the difference was statistically non-significant. This study may be helpful in developing a regional exposure database and in the facilitation of health risk assessment due to volatile organic pollutants in our day-to-day environment.

A correlation of secondary aerosol (nitrate and sulfate) with respirable particulate matter (RPM) in ambient air at different traffic junctions of Vadodara city.

The correlation study of secondary aerosol (nitrate and sulfate) with RPM in ambient air at different traffic junctions of Vadodara city is reported. RPM was analyzed using Ion Chromatography technique and measured the level of nitrate and sulfate in ambient air. The correlation studies of these particulates with RPM have been established. The average concentration of sulfate and nitrate in ambient air was found 35.74 microg/m3 and 24.22 microg/m3, which ranged of 5.33-84.69 and 1.93-77.86 microg/m3 respectively. The correlation of RPM and SO4 (r = 0.813, P<0.01), RPM-NO3 (r = 0.5549, P<0.01) and SO4-NO3 (r = 0.6133, P<0.01) were found significant. The presence of sulfate and nitrate in RPM is 8.25% and 5.60% . The pH of water extract of RPM averaged 6.81, which ranged 6.17-7.28. Regression analysis result showed that the relationship between RPM-SO4 was significantly (R2=0.66215) correlated. This indicate that probably the secondary aerosols such as nitrate and sulfate in excess may cause irritation and increasing lung disease.

Gas chromatographic-mass spectroscopic determination of benzene in indoor air during the use of biomass fuels in cooking time.

A gas chromatography-mass spectroscopic method in electron ionization (EI) mode with MS/MS ion preparation using helium at flow rate 1 ml min(-1) as carrier gas on DB-5 capillary column (30 m x 0.25 mm i.d. film thickness 0.25 microm) has been developed for the determination of benzene in indoor air. The detection limit for benzene was 0.002 microg ml(-1) with S/N: 4 (S: 66, N: 14). The benzene concentration for cooks during cooking time in indoor kitchen using dung fuel was 114.1 microg m(-3) while it was 6.6 microg m(-3) for open type kitchen. The benzene concentration was significantly higher (p < 0.01) in indoor kitchen with respect to open type kitchen using dung fuels. The wood fuel produces 36.5 microg m(-3) of benzene in indoor kitchen. The concentration of benzene in indoor kitchen using wood fuel was significantly (p < 0.01) lower in comparison to dung fuel. This method may be helpful for environmental analytical chemist dealing with GC-MS in confirmation and quantification of benzene in environmental samples with health risk exposure assessment.

Epithelial healing rates with topical ciprofloxacin, ofloxacin, and ofloxacin with artificial tears after photorefractive keratectomy.

PURPOSE: To determine whether corneal epithelial healing differs after the use of topical ciprofloxacin alone, topical ofloxacin alone, or topical ofloxacin with artificial tears in patients having photorefractive keratectomy (PRK). SETTING: Department of Ophthalmology and Visual Science, The University of Texas Health Science Center at Houston, Houston, Texas, USA. METHODS: Eighteen patients (6 women, 12 men) with moderate myopia (-1.50 to -6.00 diopters [D]) had standardized PRK. Patient age ranged from 25 to 62 years. The 28 eyes (16 right, 12 left) were randomized into 3 treatment groups: ofloxacin alone, n = 9 eyes; ciprofloxacin, n = 9 eyes; and ofloxacin with Refresh Plus, n = 10 eyes. The drugs were administered immediately after surgery and then every 6 hours. Video recordings of the corneal wounds stained with fluorescein were performed at 8:00 AM and 4:00 PM using a video slitlamp camera with a cobalt-blue light until the wound completely healed. The videotaped images were recorded and analyzed by a computer planimetry program. Wound areas were recorded and compared among the 3 drugs. The square-root transformation was applied to the wound area to obtain a constant healing rate. Statistical comparisons were analyzed using an analysis of variance test. RESULTS: Mean recovery time was 82.67 hours +/- 14.42 (SD) in the ofloxacin eyes, 120.89 +/- 34.05 hours in the ciprofloxacin eyes, and 76.80 +/- 19.30 hours in the ofloxacin with Refresh Plus eyes. Mean healing rate was 0.66 +/- 0.17 hours, 0.54 +/- 0.16 hours, and 0.67 +/- 0.15 hours, respectively. The healing rate was significantly higher in the ofloxacin with Refresh Plus eyes than in the ciprofloxacin eyes (P < .0001). There was no significant difference between the ofloxacin eyes and the ofloxacin with Refresh Plus eyes (P = .42). CONCLUSION: Ofloxacin with Refresh Plus and ofloxacin alone had a more positive effect on epithelial healing than ciprofloxacin. The ciprofloxacin eyes were significantly more prone to impaired or delayed wound healing and to the development of corneal haze.

Nitric oxide synthase inhibitors alter ventilation in isoflurane anesthetized rats.

BACKGROUND: Nitric oxide (NO) is present in medullary structures and can modulate respiratory rhythm. The authors determined if spontaneous ventilation at rest and in response to increased carbon dioxide is altered by selective neuronal NO synthase (NOS; 7-nitro-indazole, 7-NI) or nonselective (neuronal plus endothelial) NOS (NG-L-arginine methyl ester [L-NAME] and NG-monomethyl L-arginine [L-NMMA]) inhibitors in rats anesthetized with isoflurane. METHODS: Fifty-four rats received either L-NAME or L-NMMA (1, 10, and 30 mg/kg) or 7-NI (20, 80, and 400 mg/kg) and were compared with time controls (isoflurane = 1.4%), with isoflurane concentrations (1.6%, 1.8%, and 2%) increased consistent with the increased anesthetic depth caused by NOS inhibitors, or with L-arginine (300 mg/kg). Tidal volume (VT), respiratory frequency (f), minute ventilation (VE), and ventilatory responses to increasing carbon dioxide were determined. RESULTS: L-NAME and L-NMMA decreased resting VT and VE, whereas 7-NI had no effect. Increasing concentrations of isoflurane decreased resting f, VT, and VE. L-NAME and L-NMMA decreased VT and VE, whereas 7-NI had no effect at 8%, 9%, and 10% end-tidal carbon dioxide (ETCO2). Increasing concentrations of isoflurane decreased f, VT, and VE at 8%, 9%, and 10% ETCO2. The slope of VE versus ETCO2 was decreased by isoflurane but was unaffected by L-NAME, L-NMMA, or 7-NI. L-arginine alone had no effect on ventilation. CONCLUSIONS: Nonselective NOS inhibitors decreased VT and VE at rest and at increased carbon dioxide levels but did not alter the slope of the carbon dioxide response. Selective neuronal NOS inhibition had no effect, suggesting that endothelial NOS may be the isoform responsible for altering ventilation. Finally, the cause of the decreased ventilation is not a result of the enhanced anesthetic depth caused by NOS inhibitors.