Canine leishmaniasis: epidemiological risk and the experimental model

Increasing risk factors are making zoonotic visceral leishmaniasis a growing public health concern in many countries. Domestic dogs constitute the main reservoir of Leishmania infantum and Leishmania chagasi, and play a key role in the transmission to humans. New reagents and tools allow the detailed investigation of canine leishmaniasis, permitting the monitoring of the immunological status of dogs in both natural and experimental infections. Such studies are essential to determine the basis of the canine protective immune response and to establish a laboratory model, a significant aspect for the development of vaccines against canine leishmaniasis.     

Differential response of lymphocytes and neutrophils to high intensity physical activity and to vitamin C diet supplementation

We have determined the effects of chronic vitamin C intake on neutrophil and lymphocyte antioxidant defences during the acute phase immune response induced by intense exercise. Blood samples were taken from 16 voluntary athletes in basal conditions, both immediately after and 1 h after a duathlon competition. Sportsmen's nutrient intakes were determined before the competition. After determining the basal plasmatic ascorbate levels, the results were analysed taking into account the vitamin C intake and their plasmatic levels. Two groups were constituted, the vitamin C supplemented group and the control group, with the dietary vitamin C intake as the only statistical difference between groups. The duathlon competition induced a significant neutrophilia, which was higher in the supplemented group. Lymphocyte antioxidant enzyme activities increased after the competition, with a higher increase in SOD activity in the control group than in the supplemented one. The competition decreased neutrophil antioxidant enzyme activities and neutrophil ascorbate concentration. The decrease in the SOD activity in the supplemented group was higher than in the control group. Finally, the duathlon competition increased the expression of MAC-1 neutrophil adhesion molecule in the supplemented group. High vitamin C intake influenced the response of neutrophils and lymphocytes to oxidative stress induced by exercise, increasing the neutrophil activation.     

Protective efficacy of a DNA influenza virus vaccine is markedly increased by the coadministration of a Schiff base-forming drug

Effective vaccination against heterologous influenza virus infection remains elusive. Immunization with plasmid DNA (pDNA) expressing conserved genes from influenza virus is a promising approach to achieve cross-variant protection. However, despite having been described for more than a decade, pDNA vaccination still requires further optimization to be applied clinically as a standard vaccination approach. We have recently described a simple and efficient approach to enhance pDNA immunization, based on the use of tucaresol, a Schiff base-forming drug. In this report we have tested the ability of this drug to increase the protection conferred by pDNA vaccination against influenza virus infection. Our results demonstrate that a significant protection was achieved in two strains of mice by using the combination of pDNA and tucaresol. This protection was associated with an elevated humoral and cellular response and a switch in the type of the T helper cell (Th) immune response from type 2 to type 1. This vaccine combination represents a promising strategy for designing a clinical study for the protection from influenza and similar infections.     

Maximizing strength development in athletes: a meta-analysis to determine the dose-response relationship

The efficiency, safety, and effectiveness of strength training programs are paramount for sport conditioning. Therefore, identifying optimal doses of the training variables allows for maximal gains in muscular strength to be elicited per unit of time and also for the reduction in risk of overtraining and/or overuse injuries. A quantified dose-response relationship for the continuum of training intensities, frequencies, and volumes has been identified for recreationally trained populations but has yet to be identified for competitive athletes. The purpose of this analysis was to identify this relationship in collegiate, professional, and elite athletes. A meta-analysis of 37 studies with a total of 370 effect sizes was performed to identify the dose-response relationship among competitive athletes. Criteria for study inclusion were (a) participants must have been competitive athletes at the collegiate or professional level, (b) the study must have employed a strength training intervention, and (c) the study must have included necessary data to calculate effect sizes. Effect size data demonstrate that maximal strength gains are elicited among athletes who train at a mean training intensity of 85% of 1 repetition maximum (1RM), 2 days per week, and with a mean training volume of 8 sets per muscle group. The current data exhibit different dose-response trends than previous meta-analytical investigations with trained and untrained nonathletes. These results demonstrate explicit dose-response trends for maximal strength gains in athletes and may be directly used in strength and conditioning venues to optimize training efficiency and effectiveness.     

An alpha-glucan elicitor from the cell wall of a biocontrol binucleate Rhizoctonia isolate

Binucleate Rhizoctonia (BNR) isolate (232-C6) is an effective biocontrol agent for protection of potato from Rhizoctonia canker, a disease caused by Rhizoctonia solani. Production of hydrolytic enzymes is one of the best known inducible defense responses following microbial infection. We isolated and characterized a cell wall alpha-glucan from BNR, which induces beta-1,3 glucanase activities in potato sprouts, the primary site of infection by R. solani. An autoclaving method, previously reported for isolation of oligosaccharide elicitors was used, and the glucan purified by chromatographic techniques. Maximal induction of beta-1,3 glucanase activity in potato sprouts was obtained with 250 microg of the alpha-glucan elicitor after 6 days from inoculation time. Both, BNR mycelium and the alpha-glucan produced a similar kinetic response of beta-1,3 glucanase. However, the alpha-glucan did not induce phytoalexin accumulation, previously correlated with the defense response. Uronic acids (approximately 10% with respect to total neutral sugars) were determined and identified as glucuronic acid by high-pH anion-exchange chromatography. Methylation analysis showed that the glucan consists of (1-->3) and (1-->4)-linked glucose units with preponderance of the first ones. Some of the (1-->4) linkages were branched at position 6. The glucan was partially degraded with amyloglucosidase. This, together with the NMR spectra data and the high optical rotation of the original (+195 degrees ) and degraded glucans (+175 degrees ) proved the alpha configuration. Further methylation of the amyloglucosidase degraded glucans indicated that they consist of (1-->3)-linked glucoses. The present study is the first report on the isolation and characterization of an alpha-glucan from Rhizoctonia, that may be important as a biocontrol factor.     

Prevalence of Pre‐obesity and Obesity in Urban Adult Mexicans in Comparison with Other Large Surveys

Objective: 1. To estimate the prevalence of pre‐obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. Research Methods and Procedures: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5 to 24.9 kg/m²), pre‐obesity (PreOB = BMI 25 to 29.9 kg/m²) and obesity (OB = BMI 30+ kg/m²). Estimates for Mexican Americans were calculated from U.S. survey data. Results: Overall, 38% of the Mexican urban adult population were classified as pre‐obese and 21% as obese. Men had a higher prevalence of pre‐obesity than women did at all ages, but women had higher values of obesity. Both pre‐obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre‐obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre‐obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre‐obesity and obesity. Discussion: Pre‐obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.     

Linking fisheries management and conservation in bioengineering species: the case of South American mussels (Mytilidae)

We examined a complete list of South American mussels (Mytilidae) to identify species with current or potential needs for management and conservation actions. Based on ecological/ecosystem (aggregations, beds or banks affecting ecosystem functioning) and socio-economic (artisanal fisheries or aquaculture systems) attributes species with high relevance were identified. At least 14 species exhibited large ecosystem level effects at local scales. Further, most of them also sustain important fisheries: nearly one/third of these fisheries showed characteristics that may contribute to their lack of sustainability and overexploitation, while half are either in the initial exploitation phase or in the stabilization of extraction and institutionalization phase. Invading species are modifying the structure of mussel habitats. Allocation of spatially explicit management tools, notably Territorial User Rights in Fisheries and Marine Reserves, together with co-management initiatives, are suggested as relevant tools to fulfill management and conservation objectives for these key bioengineering species.