Cytogenetic assays in genotoxic studies: Somatic cell effects of benzene and germinal cell effects of dibromochloropropane

The genotoxic effc of NO2 was investigated on somatic human chromosomes obtained from lymphocytes of45 goldsmiths exposed to 1770.5 mg/m3 NO1 in ambient air at normal temperatre and pressure and compared to an equal number of matched control breadting air containing 50 pg/m3 NOr. Short-term lymphocyte culres were set up from blood collected from both exposed and control individuals by venipuncue in heparinized sterile syringes. Mitotic We conducted an epidemiological survey using a proforma especially designed for this purpose. After obtaining consent, we performed subsequent medical examinations of subjects suffering from asthma.Short-term lymphocyte cultures were prepared from heparinized blood (heparin 500 IU/ml without preservative) according to the method of Moorhead et al. (3), with slight modifications. Blood (0.5 ml) was added to 5 ml RPMI 1640 medium containing 20% fetal calf serum, 100 IU/ml penicillin, 100 pg/ml streptomycin, and 0.1 ml phytohemagglutinin (Sigma, St. Louis, MO). Colchicine (10 pg/ml) was added to the culture 2 hr before harvesting.Lymphocytes were harvested after 48 hr for determination of mitotic index (MI), chromosomal aberrations (CAs), and satellite associations (SAs). Slides were air dried and stained with 4% Giemsa. As many as 100 good metaphases (well-spread metaphases showing 2N-46 and proper morphology of chromosomes) per individual were screened for CAs.To determine sister chromatid exchanges (SCEs), we added 5-bromodeoxyuridine (10 pg/ml/culture; Sigma) 24 hr after preparing cultures. We used the method of Perry and Wolff (4) with the following modifications: 1) the cells on slides were stained directly in excess solution of Hoechst 33258 (50 pg/ml in H20; Sigma); 2) the slides were exposed to long-wave UV light of about 320-400 mm intensity; 3) the slides were rinsed with water and incubated for 15-30 min in 2X SSC at 65°C; and 4) the slides were rinsed with water and stained with 2-3% Giemsa in phosphate buffer (pH 6.8 ResultsThe epidemiological survey showed that 6 individuals out of the sample of 45 goldsmiths were asthmatic. As many as 30 persons also complained of irritation in the eyes.The data obtained during this study are presented in Tables 1-8. It is evident from Tables 1 and 2 that mean MI in exposed workers (9.57) was significantly higher (p<0.01) than in matched controls (5.01). It was highest in workers with an exposure period of 0-5 years. Thereafter, the MI showed a gradual decline.We found chromosomal aberrations to be elevated in the group exposed to NOX.Yields of aberrations in goldsmiths are presented in Table 3, and raw data are given in Table 4. Frequencies of all types of CAs such as dicentrics, rings, acentric fragments, chromatid gaps, breaks, and isochromatid aberrations were significantly higher in the

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“…To determine sister chromatid exchanges (SCEs), we added 5-bromodeoxyuridine (10 pg/ml/culture; Sigma) 24 …”

Section: Methodsmentioning

confidence: 99%

Effect of NOx on the somatic chromosomes of goldsmiths.

Yadav

Seth

1998

Environ Health Perspect

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“…Total volatile organic compound measurements may not correlate with symptoms in these individuals (79). There is also evidence that low levels of mixtures of genotoxic chemicals (including benzene) may actually be more damaging than higher levels because they do not trigger an appropriate induction of detoxification enzymes (80). In addition, there is evidence that the synergistic effect of multiple low levels of potentially toxic xenobiotics may be clinically relevant, as appears to be the case in chemically exposed Persian Gulf War (PGW) veterans (81).…”

Section: The Patterns Of Exposure Causing Symptoms Of Mcs/ieimentioning

confidence: 99%

Multiple chemical sensitivity and idiopathic environmental intolerance (part one)

Watanabe

Tonori

Aizawa

2003

Environ Health Prev Med

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Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms. These symptoms have been described and commented on for more than 15 years in the USA. Recently, it has also been observed in Japan. The main features of this syndrome are multiple symptoms involving in multiple organ systems that are precipitated by a variety of chemical substances with relapses and exacerbation under certain conditions when exposed to very low levels which do not affect the population at large. There are no laboratory markers or specific investigative findings. Although traditional medical organizations have not agreed on a definition for this syndrome due to the lack of obvious evidence to demonstrate the existence of these symptoms, it is being increasingly recognized. It constitutes an increasing percentage of the caseload at occupational/environmental medical clinics.Part one of this review article discusses pathophysiological theories, substances which cause symptoms, prevalence in the general and specific populations, past history and family history, and clinical symptoms of MCS/IEI patients.

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“…Others contend that these substances are foreign to the body and that the ordinary dose-response curve assumptions may not apply for low levels of these toxic xenobiotics. Indeed, there is evidence that low levels of mixtures of genotoxic chemicals (including benzene) may actually be more damaging than higher levels because they do not trigger an appropriate induction of detoxification enzymes (31). In addition, there is evidence that the synergistic effect of multiple low levels of potentially toxic xenobiotics may be clinically relevant, as appears to be the case in chemically exposed Gulf War veterans (32).…”

Section: L-boratory Investigationmentioning

confidence: 99%