Effects of exposure to halogenated organic compounds combined with dietary restrictions on the antioxidant defense system in herring gull chicks

The Herring gull (HG) (Larus argentatus) is naturally exposed to halogenated organic compounds such as polychlorinated biphenyls (PCBs) through its diet. During periods of food scarcity, arctic seabirds experience lipid mobilization, allowing stored lipid soluble contaminants to re-enter the body circulation. In the present study, we investigated the effects of PCB exposure and fasting on the antioxidant defense system in HG chicks. Forty newly hatched chicks were exposed to contaminated cod liver oil for 6 weeks and then fasted for 1 week. We assessed the hepatic total oxyradical scavenging capacity (TOSC) against peroxynitrite, hydroxyl and peroxyl radicals, and measured glutathione (reduced: GSH, and oxidized: GSSG) levels and the enzymatic activities of catalase, glutathione peroxidase, glutathione reductase and superoxide dismutase. The results show that fasting significantly increased the HOC levels in the HG chick livers. Limited effects were observed on antioxidant responses; significant effects were only found for catalase (CAT) activity, Se-dependent GPX activity and the GSH/GSSG ratio in the exposed and fasted group. CAT and Se-dependent GPX activities correlated negatively with the PCB concentrations within this group, and a nonlinear relationship between glutathione and contaminant levels was also found. These effects were generally not observed after exposure or fasting alone and were likely related to the high PCB levels induced by the combination of exposure and fasting.     

Biomarker responses and PAH uptake in Mya truncata following exposure to oil-contaminated sediment in an Arctic fjord (Svalbard)

Expanding industrial activity (notably oil and gas exploration) in the Arctic requires assessment of the potential impact of chemicals on marine organisms living in seawater at low temperature. The bivalve Mya truncata is common in Svalbard fjord (Norway) where it experiences low temperature throughout the year. To measure the impact of polycyclic aromatic hydrocarbons (PAH) on M. truncata, the responses of three biomarkers [total oxyradical scavenging capacity-assay (TOSC), plasma membrane stability of haemocytes and respiration rates] were investigated from bivalves exposed to sediment contaminated with a PAH mixture (crude oil). After two weeks of exposure to the contaminated sediment, TOSC showed no change. The high TOSC value (4010+/-1339 unit mg(-1) protein) of Mya truncata (control group) is thought to protect biomolecules with a low turnover rate efficiently in a low food availability environment. In the exposed bivalves, the haemocyte cellular membranes were significantly destabilised compared with controls (P<0.05). Respiration rate of control and PAH-exposed individuals (0.055+/-0.020 mg O(2) dw(-1) h(-1)) was similar and relatively low as is typical for polar bivalves, reflecting a strategy to minimise energy expenditure to cope with 9 months of starvation. Bioaccumulation of PAH by M. truncata was also low, due probably to a combination of low metabolic rate and reduced solubility of the oil compounds at low temperature. Data indicated an uptake of mainly low molecular weight compounds (two and three ring molecules). A good correlation of logBAF(lipid) (bioaccumulation factor) and logK(ow) (octanol/water partitioning coefficient) was shown (r(2)=0.87). Tissue sensitivity and/or functional differences (digestive gland vs. haemocytes), PAH uptake route (dietary vs. gills), the low metabolic rate of M. truncata and the low environmental temperature (reducing the bioavailability of PAH) are factors that help explain these findings.     

Synthesis of ferroquine enantiomers: first investigation of effects of metallocenic chirality upon antimalarial activity and cytotoxicity

Ferroquine (FQ) is a new antimalarial agent with a high blood schizotoncidal activity. Previous studies on this compound were done with racemate mixtures. As FQ possesses planar chirality, pure enantiomers were obtained by enzymatic resolution in order to compare their antimalarial activities and cytotoxicities. (+)-FQ and (-)-FQ were equally active in vitro, at nanomolar concentrations. Both enantiomers were slightly less active than the racemate in vivo; cytotoxicities were similar. Actually, the racemate represents the optimal formulation. To the best of our knowledge, this is the first investigation of biological activities of compounds with metallocenic chirality.     

Prognostic sperm factors in intra-uterine insemination with partner's sperm

We studied the prognostic value of sperm characteristics for the outcome of intra-uterine insemination with partner sperm (IUIPS). A total of 712 cycles of IUIPS following induction of ovulation with gonadotrophin (hMG/hCG) for 277 sterile couples attending the assisted reproductive technology centre of Poissy Hospital (78300-France) between January 1991 and December 1994 was studied retrospectively. Ninety-two clinical pregnancies were obtained giving an overall rate of 12.9% per cycle. None of the characteristics of the sperm as assessed initially correlated with outcome. In contrast, the number of motile spermatozoa given (n) affected outcome: for n < 1 x 10(6) the pregnancy rate was 2%; for n = 5 to 8 x 10(6) the rate was 19%. However, for +/- 8 x 10(6) the proportion of biochemical pregnancies and miscarriages was 40% which was significantly higher than for smaller concentration. The resort of IVF following 4 IUIPS failures leads to a pregnancy rate per cycle of only 6.7%.