RESUMEN
The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCEs) in the peripheral blood lymphocytes of 360 persons, 180 workers in a petrochemical corporation and 180 appropriate controls, were studied. A significant increase in chromosomal aberrations and SCEs, compared to the control group, was observed in two sewage-treatment workshop workers; however, there were no significant differences between petrochemical workers from four workshops and a control group.
Asunto(s)
Industria Química , Aberraciones Cromosómicas , Medicina del Trabajo , Petróleo , Intercambio de Cromátides Hermanas , Adulto , Femenino , Humanos , Linfocitos/ultraestructura , Masculino , Ocupaciones , FumarRESUMEN
Hydroxyurea (HU) is an inhibitor of DNA synthesis, which can inhibit the enzyme ribonucleotide reductase, reduce the syntheses of all four deoxyribonucleoside diphosphates (dNDP), and disturb the balance of the dNTP pool. We have studied the effect of HU on the common fragile site at 3p14 (FRA3B) and have found that G2 treatment with HU increased not only the frequency of chromosomal aberration but also the expression of FRA3B in both complete and folate deficient media. There is a synergistic effect between HU and growth in folate deficient medium on the induction of FRA3B. Our results suggest that the inhibition of DNA repair, including the inhibition in G2 phase, plays an important role in the expression of FRA3B, supporting other authors' data on the effect of other DNA repair inhibitors, such as aphidicolin, caffeine, 1-beta-D-arabinofuranosylcytosine, and 5-fluorodeoxyuridine, on the expression of FRA3B.
Asunto(s)
Fragilidad Cromosómica , Cromosomas Humanos Par 3 , Regulación de la Expresión Génica/efectos de los fármacos , Hidroxiurea/farmacología , Cafeína/farmacología , Aberraciones Cromosómicas , Sitios Frágiles del Cromosoma , Reparación del ADN/efectos de los fármacos , Replicación del ADN/efectos de los fármacos , Femenino , Humanos , Interfase/efectos de los fármacos , MasculinoRESUMEN
There is a synergistic effect between hydroxyurea (HU) and high concentrations of thymidine (TdR) on the induction of the common fragile sites at 3p14 and 16q23. The frequencies of expression of these fragile sites were significantly higher than in the controls when excessive TdR (0.5 mM) and HU (4 mM) were added into lymphocyte cultures in MEM medium 24 h and 2 h before harvest. Two conditions for the maximum expression of common fragile sites, such as fra(3)(p14), fra(16)(q23) are discussed. The TdR-HU fra(3)(p14)-inducing system might be modified effectively and consistently to improve the prenatal diagnosis of the fragile X syndrome.
Asunto(s)
Fragilidad Cromosómica , Cromosomas Humanos Par 16 , Cromosomas Humanos Par 3 , Hidroxiurea/farmacología , Timidina/farmacología , Sitios Frágiles del Cromosoma , Sinergismo Farmacológico , HumanosRESUMEN
The effect of the G2-treatment of 1-beta-D-arabino-furanosyl-cytosine (araC) on the expression of the common fragile site at 3p14 (FRA3B) was studied. A significantly increased frequency of FRA3B induced by G2 treatment of araC was found in the lymphocytes grown in folate-deficient medium (positive rate 100%). A relatively low frequency of FRA3B was also induced in the cultures with folate in four of the seven subjects. There is a synergistic effect between araC and growth in folate-deficient medium on the induction of FRA3B. The results suggest that the DNA lesions related to the expression of FRA3B induce the long-patch repair and that the low DNA polymerase alpha activity and inefficient repair process during G2 phase is involved in the expression of FRA3B.