Genotoxic and histotoxic effects of air pollutants at a benzene station on albino rats

Background: This study was designed to explore the hazardous effects of occupational exposure to air pollutants arising from benzene stations.Methods: A total of 48 albino rats were divided into three groups each of sixteen animals. Groups-I and II were kept at a benzene station for 60 and 120 days, respectively; while group-III was kept as a control under normal laboratory conditions. At the end of the experiment, animals were sacrificed and bone marrow samples were taken to investigate the effect of air pollutants at a benzene station on chromosomal aberrations and micronuclei formation. Tissue samples were also picked out to evaluate histotoxic effects of these air pollutants.Results: Results indicated pronounced time-dependent effects because of the work place pollutants. Genetic examination revealed higher frequency of chromosomal aberrations and elevated mitotic index after exposure to air pollutants. Micronuclei formation also increased either in polychromatic or normochromatic erythrocyte due to air pollutants. Histopathological examination revealed congestion of the pulmonary blood vessels with pulmonary edema. Bronchial hyperplasia and metaplasia were also seen in late stage of exposure. The liver showed degenerative changes or even necrosis of hepatocytes, while the kidneys showed congestion of the renal blood vessels and glomerular tufts. Hyalinization of the glomeruli was also detected. The heart showed various mononuclear infiltration and the testes showed degenerative changes of seminiferous tubules. Spleen showed hemosiderosis while testes showed degenerative changes of seminiferous tubules.Conclusions: The findings of the present study indicated that benzene exposure may lead to toxic effects including, genotoxicities and histotoxicities. In order to minimize the predicted toxic effect of occupational exposure to benzene the strict protective measures should be put in consideration

Genotypic detection of rifampicin and isoniazid resistant Mycobacterium tuberculosis strains by DNA sequencing: a randomized trial

Correction to Genotypic detection of rifampicin and isoniazid resistant Mycobacterium tuberculosis strains by DNA sequencing: a randomized trial Amina Abdelaal, Hassan Abd El-Ghaffar, Mohammad Hosam Eldeen Zaghloul, Noha El mashad, Ehab Badran, Amal Fathy Annals of Clinical Microbiology and Antimicrobials 2009, 8:4 (30 January 2009

Fan and Ventilation Rate Monitoring of Cage-Free Layer Houses in California

Ventilation rates were continuously monitored in two cage-free layer houses located in California from March 1, 2012 to May 13, 2013. The average number of brown Lohmann laying hens in each house was 33,300. Temperature, relative humidity, static pressure, and running status of 48 ventilation fans were continuously monitored and recorded every minute. Regression models were developed to relate house temperature and ventilation rate to inlet air temperature, and to relate airflow rate to building static pressure (R2 = 0.98). Results showed that the daily mean ventilation rate per hen ranged from 1.91 to 8.72 m3 h-1 hen-1, averaging at 4.49 ±1.53 m3 h-1 hen-1. The standard uncertainty of daily mean ventilation rate was determined to be 3.7%. The 91-cm and 130-cm fans were found to perform at 82% and 63% of the manufacturer rated airflow rates, respectively. The minimum and maximum static pressure was 11.0 and 50.6 Pa, respectively, corresponding to 2 and 16 running tunnel fans. When the house temperature exceeded 30ºC, an evaporative cooling system was activated, which could reduce the inlet air temperature by 6.3ºC and concurrently increased the indoor air humidity ratio by 3.4 g per kg dry air. Cooling pad efficiency was 66%. The sidewall fans and tunnel fans were operated at 65% and 20% of the total time when layers occupied the houses. The new rational formula to calculate dry base ventilation rates was developed based upon the ratio of water vapor volume to moist air volume. The developed models and data collected in this research can be used to calculate the ventilation rates in cage-free layer houses so that it can be possible to assure healthy conditions needed for layers. They can also be used in the design of cage free houses and in the calculations of emissions of air pollutants from these houses