In vivo differentiation of Trypanosoma cruzi - 1. Experimental evidence of the influence of vector species on metacyclogenesis

Vector species has not hitherto been studied as influencing metacyclogenesis of Trypanosoma cruzi, while the role of the parasite strain has been frequently stressed as of dominant importance in this process. In order to fill this gap in our knowledge, metacyclogenesis was monitored in nine triatomine species. The first part of this paper presents photographs of the main and intermediate parasite stages in each vector species studied. In the second part of the study the proportional distribution of all these forms, as seen in Giemsa stained smears is summarized, thus providing an opportunity to analyze both: the length of time between the ingestion of the blood trypomastigotes and the appearance of metacyclic forms and the rates of developmental stages leading to these latter. The most remarkable observation was that metacyclogenesis rates in vivo appear to be vector dependent, reaching 50 in Rhodnius neglectus, 37 in its congener R. prolixus and being dramatically lower in the majority of Triatoma species (5 in T. sordida, 3 in T. brasiliensis and 0 in T. pseudomaculata) at the 120th day of infection. These observations suggest that through screening of different vector species it is possible to find some that are capable of minimizing or maximizing metacyclic production.

Integrated control measures against Culex quinquefasciatus, the vector of filariasis in Recife

Integrated control measures against Culex quinquefasciastus have been implemented in a pilot urban area in Recife, Brazil. About 3,000 breeding sites found within the operational area were responsible for very high mosquito densities recorded during the pretrial period. Physical control measures have been applied to cess pits before starting a series of 37 treatments of the other sites with Bacillus sphaericus strain 2362, over 27 months. In spite of the difficulties due to environmental conditions, very significant reductions in preimaginal population of C. quinquefasciatus were achieved and, as a consequence, low adult mosquito densities were maintained for a relatively long period of time. Entomological and environmental data gathered in this pilot project can contribute to design an integrated mosquito control program in Recife city.

Highly inducible synthesis of heterologous proteins in epithelial cells carrying a glucocorticoid-responsive vector.

A glucocorticoid-responsive vector is described which allows for the highly inducible expression of complementary DNAs (cDNAs) in stably transfected mammalian cell lines. This vector, pLK-neo, composed of a variant mouse mammary tumor virus long terminal repeat promoter, containing a hormone regulatory element, a Geneticin resistance-encoding gene in a simian virus 40 transcription unit, and a polylinker insertion site for heterologous cDNAs, was used to express the polymeric immunoglobulin (poly-Ig) receptor and the thymocyte marker, Thy-1, in Madin-Darby canine kidney (MDCK) cells and in murine fibroblast L cells. A high level of poly-Ig receptor or Thy-1 mRNA accumulation was observed in MDCK cells in response to dexamethasone with a parallel ten- to 200-fold increase in protein synthesis depending on the recombinant protein and the transfected cell clone.

Life history correlates of adult size in the malaria vector Anopheles darlingi

Adult dry weights of laboratory-reared Anopheles darlingi were highly correlated with wing lengths, which were used to estimate size variation in natural populations of this species. Significant differences in mean wing lengths of females trapped at baits were detected among collections in the same week at one site, but not between three sites in Brazil and Boliva. Relatively higher variability of wing lengths, compared to collections of other Anopheles (Nyssorhynchus), and platykurtic size distributions in large, single-night collections suggested that An. darlingi females caught at baits emerged from heterogenous larval habitats. No relationship was detected between parous state and the body size of wild-caught females. Adult males and females of laboratory-reared An. darlingi did not differ in body size. This absence of sexual size dimorphism is rare among mosquitoes and has not been noted previously in the genus Anopheles.

Primordial Perturbations in Einstein-Aether theories

El nostre objectiu es l'estudi d'extensions de la Relativitat General i, en particular, estem interessats en les teories que continguin camps vectorials addicionals. En aquests tipus de teories es necessari imposar que el vector ha de tenir norma fixa per evitar la presència d'un fantasma o grau de llibertat amb terme cinètic negatiu, i això implica que la simetria Lorentz està trencada espontàniament. El camp del aether només interactua gravitatòriament i la seva presència es difícil de detectar, no obstant això, durant inflació les fluctuacions del buit a escales petites d'un camp lleuger pot deixar una empremta en observables com les anisotropies del fons de radiació de microones. Les fluctuacions del Einstein-aether es comporten com els camps sense massa i això fa que inflació generi modes de longitud de ona llarga en els sectors escalar i vectorial. Hem estudiat la signatura del Einstein-aether dins l'espectre de pertorbacions primordials lluny del límit de de Sitter de inflació. Aquests modes escalars i vectorials poden deixar una empremta significativa en la radiació de fons de microones en funció dels paràmetres del model. Les observacions del fons de radiació de microones imposen restriccions fenomenològiques que redueixen els límits existents per aquesta classe de teoria. Amb aquest estudi del aether també esperem millorar el coneixement que tenim de una classe més ampla de teories que exhibeixen el mateix tipus de trencament de simetria.

Chagas Disease Vector Control in Tupiza, Southern Bolivia

Heavy domestic and peridomestic infestations of Triatoma infestans were controlled in two villages in southern Bolivia by the application of deltamethrin SC25 (2.5% suspension concentrate) at a target dose of 25 mg a.i./m². Actual applied dose was monitored by HPLC analysis of filter papers placed at various heights on the house walls, and was shown to range from 0 to 59.6 about a mean of 28.5 mg a.i./m². Wall bioassays showed high mortality of T. infestans during the first month after the application of deltamethrin. Mortality declined to zero as summer temperatures increased, but reappeared with the onset of the following winter. In contrast, knockdown was apparent throughout the trial, showing no discernible temperature dependence. House infestation rates, measured by manual sampling and use of paper sheets to collect bug faeces, declined from 79% at the beginning of the trial to zero at the 6 month evaluation. All but one of the houses were still free of T. infestans at the final evaluation 12 months after spraying, although a small number of bugs were found at this time in 5 of 355 peridomestic dependencies. Comparative cost studies endorse the recommendation of large-scale application of deltamethrin, or pyrethroid of similar cost-effectiveness, as a means to eliminate domestic T. infestans populations in order to interrupt transmission of Chagas disease

The Potential for Dispersal of Onchocerciasis in Ecuador in Relation to the Distribution of the Vector Simulium exiguum (Diptera:Simuliidae)

The future dispersal of onchocerciasis in Ecuador is dependent on the distribution of cytotypes of the vector species complex Simulium exiguum. Over the last 14 years, collections of larvae have been made from over 25 rivers, between 80-1600 m altitude, from various sites on both sides of the Andes. Analysis of larval polytene chromosomes was used to determine the distributions of each cytotype. On the western side of the Andes, the Cayapa cytotype (the only cytotype directly incriminated as a vector) has a distribution from Santo Domingo de los Colorados northwards. The Quevedo and Bucay cytotypes occur from Santo Domingo de los Colorados southwards. On the eastern side of the Andes, the Aguarico cytotype occurs in the Rio Aguarico and a new cytotype is present in the tributaries of the Rio Napo. Whether the disease will spread south of Santo Domingo and on the eastern side of the Andes depends on vector capacity of the cytotypes and the dispersal patterns of individuals infected with onchocerciasis. At present the Aguarico, Bucay and Quevedo cytotypes are known to be efficient hosts, but their biting preferences and biting densities have not yet been evaluated

An algorithm for semi-infinite polynomial optimization

"Vegeu el resum a l'inici del document del fitxer adjunt."

Rearing and Colonization of Lutzomyia evansi (Diptera: Psychodidae), a Vector of Visceral Leishmaniasis in Colombia

The sandfly Lutzomyia evansi from a focus of visceral leishmaniasis in northern Colombia was reared and maintained under laboratory conditions for five generations. The average time for total development was 41.8 days (range = 35.1- 49.6) at 25 oC and 89-95% of relative humidity. The mean number of eggs laid was lower in laboratory bred females either in pots (13.2 eggs/female) or vials (29.9 eggs/female) than in wild caught females (33.4 eggs/female). Immature mortality, mainly due to fungal and mite contamination, was higher during the first two instars than in the remaining immature stages. Adults were robust and healthy although difficult to feed on hamster or chick skin membrane. In summary, Lu. evansi is a colonizable species but requires specific conditions.

Studies on the Bacillus sphaericus Larvicidal Activity against Malarial Vector Species in Amazonia

In this work, bioassays were carried out in laboratory conditions (average temperature 26 ± 2ºC) to test ten strains of Bacillus sphaericus, isolated from Brazilian soils against third instar larvae from anopheline species recorded as malaria vectors in Amazonian - Anopheles nuneztovari and An. darlingi. With the former mosquito, three strains - S2, S20 and S46 showed relative activity, in 24 and 48 hr exposure to the B. spahericus strains. With the latter only the S2 and S20 were effective in the 48 hr reading. The studied strains that showed the most adequate response in the Amazonian region were S2 and S20 showing broader and more efficient results. Therefore, S2 was the most effective when the 24 and 48 hr readings were considered, because it showed the greatest relative activity values.

Reversible congestive heart failure associated with primary carnitin deficiency: report of a case and review of the literature.

A 5-year-old previously healthy boy was admitted for abdominal pain and vomiting. Physical examination showed tachypnoe (32/min), hepatomegaly and painful palpation of the upper right abdominal quadrant. Laboratory tests were normal except for elevated ammonium (202mcmol/l). Chest X-ray was performed, showing cardiomegaly and interstitial edema. Transthoracic echocardiography revealed dilated left cavities and LV hypertrophy together with a diffuse hypokinesia and LVEF of 30-40%. Diuretics and ACE-inhibitors were introduced. At that time, the differential diagnosis for the DCM included myocarditis, congenital or genetic, metabolic or autoimmune disease. The next day, the boy underwent cardiac magnetic resonance (CMR) examination, showing a severe dilatation of the LV with an end-diastolic diameter of 50mm and a volume of 150ml. LVEF was 20% with diffuse LV hypokinesia (Fig. 1). No late enhancement was present after Gadolinium injection, ruling out myocarditis. Further laboratory metabolic analysis indicated severely decreased total and free carnitin levels and low renal carnitin reabsorption, corroborating the diagnosis of primary carnitin deficiency (PCD). Carnitin substitution was initiated. The clinical condition rapidly improved. No symptoms of heart failure were present anymore. A follow-up CMR performed 9 months later confirmed the recovery. LV end-diastolic volume decreased from 150ml to 66ml, LVEF increased from 20% to 55% (Fig. 2). Late enhancement was absent after Gadolinum injection (Fig. 3).Carnitin is required for the transport of fatty acids from the cytosol into mitochondria during lipid breakdown. 75% of carnitin is obtained from food, 25% is endogenously synthesized. PCD is an autosomal recessive disorder resulting from impairment of a transporter activity, caused by mutation of the SLC22A5 gene. Incidence is about 1 in 40'000 newborns. Diagnosis is usually made at age 1 to 7. Three forms of PCD are described. In the form associated with cardiomyopathy, the disease is progressive and patient die from heart failure if not treated. Substitution of L-Carnitin leads to a dramatic improvement of disease course.This case underlines the crucial role of etiologic diagnostics in this reversible form of DCM. Early diagnostics and therapy are critical for the prognosis of the patient. This is furthermore an example of a role played by CMR in the diagnostic work-up of heart failure and its follow-up under therapy.