Residual effect of lambdacyhalothrin on Triatoma infestans

Insecticidal residual effect and triatomine infestation rates in houses of a community fumigated with lambdcyhalothrin (Icon) are reported. No mortality was observed in 5th-instar Triatoma infestans nymphs in 72-hr exposure test on three different surfaces, one month after fumigation for a dose of 31.5 mg am/m2. However, during post-exposure observation a mortality of 60% was recorded for those insect exposed on sprayed woodboard. The results observed with mud-containing treated walls, were markedly poorer (0% of mortality). Twelve month after spraying 40% of mortality was observed on first-instar T. infestans nymphs in 72-hr exposure test on woodboard, but lower mortality rates were observed in mud-containing materials. When the effect of deltamethrin (109 mg ai/m2) and lambdcyhalothrin (94 mg ai/m2) was compared, the former did not appear to be superior at similar loads. Both have showed a mortality rate of 30% on 5th-instar T. infestans nymphs three months post-fumigation. The dose utilized in the field fumigation was enough to get a significant (p < 0.0001) control of triatomine domestic infestation, since it was sufficient to keep 95% of the houses uninfested throughout 21 months following treatment, when compared with baseline situation. A remarkable knock-down effect on adult and nymphs forms of the insect and a high in situ mortality were observed as a result of its application, even at very low doses.

An attempt to control Phlebotomine sand flies (Diptera: Psychodidae) by residual spraying with deltamethrin in a Colombian village

An attempt was made to control phlebotomine sand flies biting indoors in a rural community near Cali, Colombia, using the residual insecticide "K-Othrine" (deltamethrin) sprayed on the inside walls of houses. Twelve houses were divided into matched pairs based on physical characteristics, one house in each pair being left untreated while the inside walls of the other were sprayed with 1 deltamethrin at a concentration of 500 mg a.i./m2. Sand flies were sampled each week using protected human bait and sticky trap collections for four months after spraying. The number of sand flies (Lutzomyia youngi) collected on sticky traps was significantly lower (P = 0.004) in the untreated houses than in the treated ones with which they were matched. This difference was not significant for L. columbiana; the other anthropophilic species were not present in large numbers. The numbers collected on human bait in treated and untreated houses were not significantly different for either species. Activity of the insecticide as determined by contact bioassays remained high throughout the study and failure to control the insects was attributed to two factors: the tendency of sand flies to bite before making contact with the insecticide and the fact that the number of sand flies that entered houses represented a relatively small proportion of the population in the wooded areas surrounding the settlement in the study.

Relationship of aerobic fitness and motor skills with memory and attention in preschoolers (Ballabeina): a cross-sectional and longitudinal study.

BACKGROUND: The debate about a possible relationship between aerobic fitness and motor skills with cognitive development in children has recently re-emerged, because of the decrease in children's aerobic fitness and the concomitant pressure of schools to enhance cognitive performance. As the literature in young children is scarce, we examined the cross-sectional and longitudinal relationship of aerobic fitness and motor skills with spatial working memory and attention in preschool children. METHODS: Data from 245 ethnically diverse preschool children (mean age: 5.2 (0.6) years, girls: 49.4%) analyzed at baseline and 9 months later. Assessments included aerobic fitness (20 m shuttle run) and motor skills with agility (obstacle course) and dynamic balance (balance beam). Cognitive parameters included spatial working memory (IDS) and attention (KHV-VK). All analyses were adjusted for age, sex, BMI, migration status, parental education, native language and linguistic region. Longitudinal analyses were additionally adjusted for the respective baseline value. RESULTS: In the cross-sectional analysis, aerobic fitness was associated with better attention (r=0.16, p=0.03). A shorter time in the agility test was independently associated with a better performance both in working memory (r=-0.17, p=0.01) and in attention (r=-0.20, p=0.01). In the longitudinal analyses, baseline aerobic fitness was independently related to improvements in attention (r=0.16, p=0.03), while baseline dynamic balance was associated with improvements in working memory (r=0.15, p=0.04). CONCLUSIONS: In young children, higher baseline aerobic fitness and motor skills were related to a better spatial working memory and/or attention at baseline, and to some extent also to their future improvements over the following 9 months. TRIAL REGISTRATION: clinicaltrials.gov NCT00674544.

Recrudescence induced by cyclophosphamide of chronic Trypanosoma cruzi infection in mice is influenced by the parasite strain

Reactivation of chronic chagasic patients may occur upon use of immunosuppressive drugs related to kidney or heart transplantation or when they are affected by concomitant HIV infection. This recrudescence, however, does not occur in all chagasic patients exposed to immunosuppressive agents. We therefore investigated the influence of Trypanosoma cruzi strains in the recrudescence of the parasitism in mice at the chronic phase treated with cyclophosphamide, an immunosuppressor that blocks lymphocytes DNA synthesis and therefore controls B cells response. A large variation was detected in the percentages of newly established acute phases in the groups of mice inoculated with the different strains. We suggest that reactivation of chronic T. cruzi infections is influenced by the parasite intrinsic characteristics, a phenomenon that might occur in the human disease.

N-terminal amino acid sequences of the major outer membrane proteins from a Neisseria meningitidis group B strain isolated in Brazil

The four dominant outer membrane proteins (46, 38, 33 and 28 kDa) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in a semi-purified preparation of vesicle membranes of a Neisseria meningitidis (N44/89, B:4:P1.15:P5.5,7) strain isolated in Brazil. The N-terminal amino acid sequence for the 46 kDa and 28 kDa proteins matched that reported by others for class 1 and 5 proteins respectively, whereas the sequence (25 amino acids) for the 38 kDa (class 3) protein was similar to class 1 meningococcal proteins. The sequence for the 33 kDa (class 4) was unique and not homologous to any known protein.

Biological comparison between three clones of Trypanosoma cruzi and the strain of origin (Bolivia) with reference to clonal evolution studies

After isolating three clones of Trypanasoma cruzi (Bolivia), we first characterized them according to parasitaemia, pleomorphism and virulence, and then histopathologically. The study's interest lies on the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. Data obtained from the studies of parasitaemia, pleomorphism and virulence showed no differences between the groups studied. As a final point, the histopathological study shows us a muscular tissue tropism both in clones and in their mother strain (Bolivia). In this paper, we conclude that Bolivia strain and clones isolated from it, pertaining to the same major clone share similar biological properties.

Positive Torsional Strain Causes the Formation of a Four-Way Junction at Replication Forks.

Research by L. Postow, C. Ullsperger, R.W. Keller, C. Bustamante, A.V. Vologodskii, and N.R. Cozzarelli, J. Biol. Chem. 2001, 276, 2790 Condensation and commentary by Alexander Bucka and Andrzej Stasiak, Universite ´ de Lausanne, Switzerland Purpose of the Study To demonstrate that positive torsional strain generated during DNA replication can lead to reversals of replication forks and, consequently can result in the formation of four-way DNA junctions

Biological characterization of clones derived from the edmonston strain of measles virus in comparison with schwarz and CAM-70 vaccine strains

Four virus clones were derived from the Edmonston strain of measles virus by repeated plaque purification. These clones were compared with the vaccine strains Schwarz and CAM-70 in terms of biological activities including plaque formation, hemagglutination, hemolysis and replication in Vero cells and chick embryo fibroblasts (CEF). Two clones of intermediate plaque yielded mixed plaque populations on subcultivation whereas the other two, showing small and large plaque sizes, showed stable plaque phenotypes. The vaccine strains showed consistent homogeneous plaque populations. All the Edmonston clones showed agglutination of monkey erythrocytes in isotonic solution while both vaccine strains hemagglutinated only in the presence of high salt concentrations. Variation in the hemolytic activity was observed among the four clones but no hemolytic activity was detected for the vaccine virus strains. Vaccine strains replicated efficiently both in Vero cells and CEF. All four clones showed efficient replication in Vero cells but different replication profiles in CEF. Two of them replicated efficiently, one was of intermediate efficiency and the other showed no replication in CEF. Two of the clones showed characteristics similar to vaccine strains. One in terms of size and homogeneity of plaques, the other for a low hemolytic activity and both for the efficiency of propagation in CEF.

Characterization of subpopulations (clones and subclones) of the 21 SF strain of Trypanosoma cruzi after long lasting maintenance in the laboratory

Several studies have shown a clonal structure of Trypanosoma cruzi and its possible correlation with the behavioral heterogeneity of the parasite strains. In the present study, the 21 SF strain, that have been maintained in laboratory by successive passages in mice, for more than 15 years, showing a stability of biological and isoenzymic characteristics has been cloned, with the objective of establishing the characters of its clones and subclones. With the technique of isolation of a single parasite from the blood of infected mice, 5 clones and 14 subclones have been obtained. After four passages into mice, inoculum of 10(5) was obtained for each clone and subclone and inoculated into mice weighing 10 to 12 g. These were used for the study of the biological behavior of the clones: evolution of parasitemia, morphology of blood forms and host mortality. For isoenzymic characterization, the clones and subclones were analyzed for ALAT, ASAT, GPI and PGM enzymes. Results have shown that the 5 clones and the 14 subclones disclosed a biological behavior similar to the parental strain, with minor variability of the parasitemic profiles and also the same isoenzymic patterns. These results confirm the stability of the 21 SF strain and indicate a clonal homogeneity of its populations. This is compatible with the hypothesis that the T. cruzi strains represent an equilibrium of either homogenous or heterogeneous populations.

The Changing Face of the Epidemiology of Tuberculosis due to Molecular Strain Typing: A Review

About one third of the world population is infected with tubercle bacilli, causing eight million new cases of tuberculosis (TB) and three million deaths each year. After years of lack of interest in the disease, World Health Organization recently declared TB a global emergency and it is clear that there is need for more efficient national TB programs and newly defined research priorities. A more complete epidemiology of tuberculosis will lead to a better identification of index cases and to a more efficient treatment of the disease. Recently, new molecular tools became available for the identification of strains of Mycobacterium tuberculosis (M. tuberculosis), allowing a better recognition of transmission routes of defined strains. Both a standardized restriction-fragment-length-polymorphism-based methodology for epidemiological studies on a large scale and deoxyribonucleic acids (DNA) amplification-based methods that allow rapid detection of outbreaks with multidrug-resistant (MDR) strains, often characterized by high mortality rates, have been developed. This review comments on the existing methods of DNA-based recognition of M. tuberculosis strains and their peculiarities. It also summarizes literature data on the application of molecular fingerprinting for detection of outbreaks of M. tuberculosis, for identification of index cases, for study of interaction between TB and infection with the human immunodeficiency virus, for analysis of the behavior of MDR strains, for a better understanding of risk factors for transmission of TB within communities and for population-based studies of TB transmission within and between countries

Characterization of a Trypanosoma rangeli Strain of Colombian Origin

A Colombian strain of Trypanosoma rangeli was characterized by analyzing its behaviour in different axenic and cellular culture, its infection rate and the histopathological lesions produced in experimental animals. Although slight inflammatory infiltrations were shown in different histopathological sections, no pseudocysts could be observed. Grace's insect medium is better than liver infusion tryptose or artificial triatomine urine supplemented with proline when studying T. rangeli metacyclogenesis, with a peak of 32% trypomastigotes. High infection rates were found in VERO and J774 cells. Because of its 100% infectivity rates and adequacy of parasitemia levels, C23 strain is a suitable model of T. rangeli biology study

Adolescència i preferències vocacionals: anàlisi comparativa per sexes, de les preferències vocacionals expressades per estudiants de 4t. d'Educació Secundària Obligatòria, a través d'un disseny longitudinal amb mostratges de subjectes diferents

Aquest treball de recerca consisteix en un estudi sobre les preferències vocacionals expressades per adolescents que cursen 4t d’Educació Secundària Obligatòria, amb una anàlisi comparativa per sexes. Es tracta d’un estudi de cas realitzat en un centre del Vallès Oriental, de caràcter longitudinal, en el que s’ha recollit durant 7 cursos acadèmics consecutius les seves preferències vocacionals a través de la prova d’interessos Kuder-C. L'objectiu ha estat comparar les preferències expressades pels nois i per les noies, les influències dels models de gènere estereotipats, així com l’existència o no de diferències entre ambdós col·lectius amb el pas del temps.

Chagas' Disease and HIV Co-infection: Genotypic Characterization of the Trypanosoma cruzi Strain

In the past few years, new aspects of the immunopathology of Chagas' disease have been described in immunosuppressed patients, such as fatal central nervous system lesions related to the reactivation of the parasite. This article is the first description of the genotypic characterization, at the strain level, of Trypanosoma cruzi isolated from a patient with Chagas` disease/AIDS co-infection. The presence of four hypodense lesions was observed in the cranial compute tomographic scan. The diagnosis of AIDS was assessed by the detection of anti-HIV antibodies using enzyme-linked immunosorbent assay (ELISA) and Western blot techniques. The CD4+ lymphocyte counts were maintained under 200 cells/mm3 during one year demonstrating the severity of the state of immunosuppression. Chagas' disease was confirmed by serological and parasitological methods. Trypomastigote forms were visualized in a thick blood smear. The parasite isolated is genotypically similar to the CL strain. The paper reinforces that cerebral Chagas' disease can be considered as another potential opportunistic infection in AIDS resulting from the reactivation of a dormant T. cruzi infection acquired years earlier.