The CFHT Open Star Cluster Survey. IV. Two Rich, Young Open Star Clusters: NGC 2168 (M35) and NGC 2323 (M50)

We continue our study of rich Galactic clusters by presenting deep CCD observations of both NGC 2168 (M35) and NGC 2323 (M50). Both clusters are found to be rich (NGC 2168 contains at least 1000 stars brighter than V = 22 and NGC 2323 contains approximately 2100 stars brighter than our photometric limit of V = 23) and young (age of NGC 2168 = 180 Myrs, age of NGC 2323 = 130 Myrs). The color-magnitude diagrams for the clusters exhibit clear main sequences stretching over 14 magnitudes in the V, B-V plane. Comparing these long main sequences with those of earlier clusters in the survey, as well as with the Hyades, has allowed for accurate distances to be established for each cluster (dist. of NGC 2168 = 912 +/- 70/65 pc, dist. of NGC 2323 = 1000 +/- 81/75 pc). Analysis of the luminosity and mass functions suggest that despite their young ages, both clusters are somewhat dynamically relaxed exhibiting signs of mass-segregation. This is especially interesting in the case of NGC 2323, which has an age of only 1.3 times the dynamical relaxation time. The present photometry is also deep enough to detect all of the white dwarfs in both clusters. We discuss some interesting candidates which may be the remnants of quite massive (M > 5 Mo) progenitor stars. The white dwarf cooling age of NGC 2168 is found to be in good agreement with the main-sequence turn-off age. These objects are potentially very important for setting constraints on the white dwarf initial-final mass relationship and upper mass limit for white dwarf production.Comment: 34 pages, including 12 diagrams and 5 tables. Accepted for publication in AJ. Minor typos correcte

The genotoxic risk of underground coal miners from Turkey

PubMedID: 16337427A cytogenetic monitoring study was carried out on a group of workers from a bituminous coal mine in Zonguldak province of Turkey, to investigate the genotoxic risk of occupational exposure to coal mine dust. Cytogenetic analysis, namely sister chromatid exchanges (SCEs), chromosomal aberrations (CAs) and micronucleus (MN) tests were performed on a strictly selected group of 39 workers and compared to 34 controls matched for gender, age, and habit. Smoking and age were considered as modulating factors. Both SCE and CA frequencies in coal miners appeared significantly higher than in controls. Similarly, there was a significant increase in the frequency of total micronuclei in exposed group as compared to control group. The effect of smoking on the level of SCE and MN was significant in the control group. A positive correlation between the age and the level of SCE was also found in controls. The frequencies of both SCE and CA were significantly enhanced with the years of exposure. The results of this study demonstrated that occupational exposure to coal mine dust leads to a significant induction of cytogenetic damage in peripheral lymphocytes of workers engaged in underground coal mining. © 2005 Elsevier B.V. All rights reserved.2003/7-47We are grateful to Osman Balamir, manager of the Armutçuk Coal Mining Institution, for his contribution to the study. The authors would like to thank health technicians of the Armutçuk Coal Mining Institution for collecting blood samples. This research was financially supported by the Research Fund of Kahramanmaras Sutcu Imam University (Grant 2003/7-47)

A biomonitoring study on the workers from textile dyeing plants

We evaluated the genotoxic risk of workers from textile dyeing plants in Kahramanmaras, Turkey. Sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) were investigated in peripheral blood lymphocyte cultures of 40 workers and compared to those of 32 age-, sex-, and habit-matched healthy controls. Groups were selected after a questionnaire administration. Use of Maras powder (a kind of smokeless tobacco) was considered as modulating factor. The SCEs level did not show significant differences between workers and controls. The frequency of CA was significantly higher in workers than in controls. Use of Maras powder was a significant factor to increase the frequencies of SCE and CA in control group. The level of SCE and CA did not correlate with the age whereas there was a significant correlation between years of exposure and CA frequency. The results of this study revealed the genotoxic risk of textile dyers. Protective measures such as masks and gloves are desirable for preventing or minimizing the occupational exposure. © Pleiades Publishing, Inc., 2006.2003/2-29ACKNOWLEDGMENTS We would like to thank the staff of the genetic laboratory of Biology Department, Çukurova University, for their kind contribution to the preparation of slides and the Research Foundation of Kahramanmaras Sütçü Imam University for financial support (project no. 2003/2-29)

Genotoxic potential of cyfluthrin

PubMedID: 18692594Cyfluthrin (CAS no. 68359-37-5), a synthetic fluorinated pyrethroid insecticide, is widely used in the home environment and in agriculture because of its high activity against a broad spectrum of insect pests and its low animal toxicity. There are no adequate data on genotoxic effects of cyfluthrin. The aim of this study was to analyze the potential genotoxic effects of cyfluthrin. The genotoxicity of cyfluthrin was evaluated, in vitro, by assessing the ability of the insecticide to induce gene mutation (evaluated using the Ames/microsome test), chromosomal aberrations (CA), sister chromatid exchange (SCE) and micronucleus (MN) formation in cultured human peripheral blood lymphocytes. Additionally, CAs and cytotoxicity induced by cyfluthrin were investigated in rat (Rattus norvegicus var. Albinos) bone-marrow cells to assess in vivo genotoxicity of cyfluthrin. The counts of reverse mutations in Salmonella typhimurium were not significantly increased (P > 0.05). The frequency of CAs in human lymphocytes, treated with any concentration of cyfluthrin (500, 1000 or 2000 µg/ml) for a 24-h period, was not significantly increased (P > 0.05). In contrast, CA was significantly increased for the highest two concentrations (1000 and 2000 µg/ml) in the 48-h treatment group compared with the control group (dimethyl sulfoxide, DMSO). Micronucleus formation was significantly (P 0.05). Mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) decreased significantly (P < 0.05) due to the potential cytotoxicity of cyfluthrin, especially after the 48-h treatment period. The frequency of chromosome aberrations in bone-marrow cells of rats treated with the test substance increased significantly (P < 0.05) for all doses (250, 500 and 1000 mg/kg body weight) for the two treatment periods (12 and 24 h) and the two administration routes, viz. intraperitoneal injection (i.p.) and oral gavage (gvg). In vivo cytotoxicity of cyfluthrin was detected only after administration by gavage for the 24-h treatment period. All these findings were not dose-dependent. © 2008 Elsevier B.V. All rights reserved

In vitro genotoxicity of rocuronium bromide in human peripheral lymphocytes

Rocuronium bromide (RB), an aminosteroid type neuromuscular blocking agent, acts by reducing or inhibiting the depolarising effect of acetylcholine on the terminal disc of the muscle cell. To our knowledge, there is no adequate information on the genotoxic effects of RB, up to now. In the present study, possible genotoxic effects of RB have been determined by means of sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) analyses in human peripheral blood lymphocytes. The human peripheral blood lymphocytes were exposed to three different concentrations of RB (60, 80 and 100 μg/mL) for 24- and 48-h. In this study, RB increased the frequency of CAs, however, did not increase the frequency of SCEs. RB did not decrease the proliferation index (PI) and mitotic index (MI). Accordingly, RB increased the frequency of micronucleus (MN) but did not decrease the nuclear division index (NDI). Findings from this study suggest that rocuronium bromide is clastogenic but not cytotoxic to cultured human peripheral blood lymphocytes