Brilliant cresyl blue staining negatively affects mitochondrial functions in porcine oocytes.

The aim of the present study was to examine the effects of brilliant cresyl blue (BCB) staining on mitochondrial functions in porcine oocytes. Cumulus-oocyte complexes (COCs) collected from slaughterhouse-derived porcine ovaries were cultured with (13 µM) or without (0 µM, control) BCB for 60 min. Mitochondrial functions in oocytes were examined immediately after staining or after in vitro maturation. The BCB-stained oocytes produced reactive oxygen species (ROS) at higher levels than control oocytes immediately after staining (2.2-fold, P < 0.001) and after maturation (1.7-fold, P < 0.001). The adenosine triphosphate (ATP) content and mitochondrial membrane potential (MMP) in oocytes were similar for the two groups immediately after staining. However, ATP and relative MMP levels were significantly (P < 0.05) lower in BCB-treated oocytes than in the control (2.18 versus 2.83 pM and 0.82 versus 1.0, respectively). There was no difference in mitochondrial DNA copy number between the two groups after maturation. The ATP content in early developmental stage embryos (3 days after parthenogenetic activation) was lower in the BCB-stained group than that in the control group but the difference was not significant. In conclusion, BCB staining of oocytes at the immature stage compromises mitochondrial functions throughout oocyte maturation, but function is restored during early embryo development.

Contamination by persistent organochlorines in cetaceans incidentally caught along Brazilian coastal waters.

Wide ranges of organochlorine residues were determined in the blubber of franciscana (Pontoporia blainvillei), estuarine dolphin (Sotalia guianensis), Atlantic spotted dolphin (Stenella frontalis), and long-beaked common dolphin (Delphinus capensis) incidentally caught along Brazilian coastal waters. Concentrations of DDTs and PCBs were the highest, followed by CHLs, TCPMOH, dieldrin, TCPMe, heptachlor epoxide, HCB, and HCHs. Unexpectedly, significant pollution of PCBs, DDTs, TCPMe, and TCPMOH were observed in cetaceans from Brazil, implying the occurrence of local sources in the Southern Hemisphere comparable to those in the Northern Hemisphere, probably by high industrialization in Brazil. On the other hand, CHLs, HCB, HCHs, heptachlor epoxide, and dieldrin residue levels in Brazilian dolphins were much lower than those in other species from the Northern Hemisphere. Significant correlations of TCPMe and TCPMOH were found along with PCBs and DDTs, indicating the highly bioaccumulative nature of all these compounds and/or possible similar pollution sources.

Cytochrome P-450 lA1 genotype in lung cancer patients and controls in Rio de Janeiro, Brazil.

Mspl restriction fragment length polymorphism in cytochrome P-450 IA1 (CypIA1) gene, which has been associated with lung cancer susceptibility in Japanese, was studied in persons from Rio de Janeiro, in the framework of a hospital-based, age, race (black or nonblack), and gender-matched case-control study (n = 222; 110 cases and 112 controls). Contrary to the hypothesis, there was no difference in the frequency of the C genotype (Mspl site-present homozygous), even after racial breakdown. There were no significant differences between cases and controls when categorized according to tobacco consumption. The lifetime quantity of tobacco smoked was not different among lung cancer patients with three different genotypes (A, Mspl site-absent, homozygous; B, heterozygote; and C). The background frequency of the Mspl polymorphism C genotype is a little less than 10%, similar to that of the Japanese healthy population. The CyplA1 Mspl polymorphism itself does not seem to be related to susceptibility to bronchial carcinogenesis in this area.