First report of knockdown mutations in the malaria vector Anopheles gambiae from Cameroon

We report the first finding of the knockdown Leu-Phe and Leu-Ser mutations associated with resistance to pyrethroids and DDT insecticides in the malaria mosquito Anopheles gambiae from Cameroon. The Leu-Phe mutation was found in both the M and S molecular forms of An. gambiae. Importantly, two specimens of the S molecular form were found to carry both mutations in a heterozygous state.     

Synthesis of Potential Impurities of Cefalexin and Cefradine

The synthesis of some impurities of the cephalosporin antibiotics cefalexin and cefradine is described. These impurities which may be present in commercial samples are formed during the semi-synthetic preparation of these antibiotics or upon their degradation. The preparation of these compounds enables the validation of selective quantitative analytical methods, such as column liquid chromatography and thin layer chromatography.     

Trends in DDT and pyrethroid resistance in Anopheles gambiae s.s. populations from urban and agro-industrial settings in southern Cameroon

Background  

Pyrethroid insecticides are widely used for insect pest control in Cameroon. In certain insect species, particularly the malaria vector Anopheles gambiae, resistance to this class of insecticides is a source of great concern and needs to be monitored in order to sustain the efficacy of vector control operations in the fields. This study highlights trends in DDT and pyrethroid resistance in wild An. gambiae populations from South Cameroon.     

Effects of Experimental Lead Exposure on Testis of the Chestnut Capped Blackbird <Emphasis Type="Italic">Chrysomus ruficapillus</Emphasis>

Lead (Pb) effects on testis histology, as well as sperm quality and oxidative status were evaluated in male Chestnut Capped Blackbird (Chrysomus ruficapillus). Wild blackbirds were captured, immediately sampled (field group) or kept in captivity and treated with a single intraperitoneal injection of saline solution (control) or saline solution with Pb acetate (50 or 100 mg/kg Pb). Seven days after injection, whole blood, ductus deferens and testis samples were collected. Increased Pb concentrations were observed in whole blood and testis of Pb-exposed blackbirds with respect to those from field and control blackbirds. Sperm cells of Pb-exposed blackbirds showed loss of membrane integrity, mitochondrial functionality, and DNA integrity. Also, oxidative damage was observed in testis of blackbirds injected with 100 mg/kg Pb. These findings indicate that Pb is accumulated in testis of C. ruficapillus, inducing severe morphological and biochemical injury that can compromise the reproductive performance of male blackbirds. Although the exposure scenario (Pb acetate, high dosage and intraperitoneal injection) tested in the present study would likely not occur in the wild, it was adequate to show potential and relevant toxic effects of Pb in wild birds.     

Multivitamin-mineral supplementation prevents lipid peroxidation during "the Marathon des Sables"

OBJECTIVE: We investigated the effect of a moderate mutivitamin and mineral supplementation containing mainly vitamin C (150.0 mg.day(-1)), vitamin E (24.0 mg.day(-1)) and beta-carotene (4.8 mg.day(-1)) prior to and during an extreme running competition -the Marathon des Sables (MDS)- that consisted of six long races in the desert. METHODS: Seventeen athletes participated in our double blind, placebo-controlled study. Blood samples were collected prior to the supplementation i.e. three weeks before the competition (D-21), two days prior to the MDS (D-2), after the third race (D3) and at the end of the competition (D7). Erythrocyte antioxidant enzyme activity (glutathione peroxidase (GPx), superoxide dismutase (SOD)), erythrocyte glutathione level (GSH), plasma non-enzymatic antioxidant status (uric acid, vitamin C, alpha-tocopherol, retinol, beta-carotene), markers of plasma lipid peroxidation (thiobarbituric reactive substances (TBARS)), reactive carbonyl derivatives (RCD) and membrane damage (creatine kinase and lactate dehydrogenase activities) were measured. RESULTS: In both groups, GSH levels, uric acid levels and membrane damage significantly increased during the competition while SOD activity significantly decreased. In Supplemented group, plasma alpha-tocopherol, beta-carotene and retinol levels significantly increased after three weeks of supplementing. In contrast to Placebo group, alpha-tocopherol, vitamin C and retinol levels were significantly affected by the competition in Supplemented group. Moreover, no increase in TBARS was observed in Supplemented group during the competition, whereas TBARS significantly increased at D3 in the placebo group. CONCLUSION: The moderate multivitamin-mineral supplementation prevented the transient increase in TBARS levels during this extreme competition.     

Knowledge and practices by adolescents in preventing occupational injuries: a qualitative study

OBJECTIVE: To describe knowledge and practices adopted by high school students to prevent occupational injuries. STUDY DESIGN: The study was carried out in a public school located in S?o Paulo, in 2003. Fifty-three evening students aged 14 to 21 years old participated the study, they were divided into two groups with and without job experience (32 and 21 students, respectively). The students answered two questions: "Why do occupational injuries occur?" and "How do you avoid occupational injuries?" Analyses were performed using the software "Quali-quanti" to structure collective discourses. ANALYSIS OF DISCOURSES: Adolescents with work experience reported that occupational injuries occur due to carelessness of the employee, bad luck of the employee, employer's negligence, lack of training, and unsafe workplace. Adolescents without work experience reported that the main causes of work injuries were carelessness of the employee and employer's negligence. Regarding the ways to protect themselves against occupational injuries, both groups reported that: they pay attention (would pay attention) and wear safety equipment (would wear) safety equipment. CONCLUSIONS: Adolescents from both groups showed limited knowledge about occupational injuries and prevention methods. Students "blamed the victim" to explain the injuries and considered "paying attention to work" as the best way to protect themselves. These facts showed that the culture of blaming the victim is present since adolescence and probably it is an outcome of a learning process of the society.     

Selenium and mortality in the elderly: results from the EVA study

BACKGROUND: Inadequate plasma selenium can adversely affect the maintenance of optimal health; therefore, reported decreases in plasma selenium in an aging population are cause for concern. To further examine this hypothesis, we explored the relationships between plasma selenium and mortality in an elderly population: the EVA (Etude du Vieillissement Artériel) study. METHODS: The EVA study was a 9-year longitudinal study with 6 periods of follow-up. During the 2-year period from 1991 to 1993 (EVA0), 1389 men and women born between 1922 and 1932 were recruited. The effects of plasma selenium at baseline on mortality were determined by Cox proportional hazards regression analysis, adjusting for the following variables: sociodemographic characteristics, dietary habits, health, and cognitive factors. RESULTS: During the 9-year follow-up, 101 study participants died. Baseline plasma selenium was higher in individuals who were alive at the end of follow-up [mean (SD), 1.10 (0.20) micromol/L] than in those who died during the follow-up [1.01 (0.20) micromol/L; P <10(-4)]. Mortality rates were significantly higher in individuals with low selenium [increments = 0.2 micromol/L; relative risk (RR) = 1.56 (95% confidence interval, 1.28-1.89)]. After we controlled for various potential confounding factors, this association remained significant [RR = 1.54 (1.25-1.88)]. When the underlying causes of death were considered, we found an association with cancer-related mortality [adjusted RR = 1.79 (1.32-2.44)]. CONCLUSIONS: Even if it is premature to present selenium as a longevity indicator in an elderly population, our results are in accordance those of large, interventional, randomized trials with selenium, which suggest that this essential trace element plays a role in health maintenance in aging individuals.