Caracterización de materiales en banda W

Para medir los coeficientes de transmisión y reflexión, S21 y S11, de diferentes materiales o muestras planas, se usa un sistema de toma de medidas en espacio libre operando banda W (75 – 110 GHz). Usando estos parámetros, S21 y S11, podemos calcular la permitividad dieléctrica relativa compleja (Er ) y la permeabilidad magnética relativa compleja (μr) mediante un proceso llamado NRW (Nicolson-Ross-Weir). El sistema para medir consiste en dos antenas de bocina, una transmisora y otra receptora, dos espejos con los que obtenemos una onda plana para medir las propiedades del material y un ordenador o dispositivo que calcula los resultados. Este dispositivo requiere de calibración para la obtención de resultados óptimos. Dicho sistema se puede simular de manera ideal con un software llamado ADS (Assistance Design System) para el estudio y comparación de grosores, permitividades dieléctricas relativas y permeabilidades magnéticas relativas de los materiales en función de la frecuencia.

Rapid diagnostic tests for the home-based management of malaria, in a high-transmission area.

Rapid diagnostic tests (RDT) are sometimes recommended to improve the home-based management of malaria. The accuracy of an RDT for the detection of clinical malaria and the presence of malarial parasites has recently been evaluated in a high-transmission area of southern Mali. During the same study, the cost-effectiveness of a 'test-and-treat' strategy for the home-based management of malaria (based on an artemisinin-combination therapy) was compared with that of a 'treat-all' strategy. Overall, 301 patients, of all ages, each of whom had been considered a presumptive case of uncomplicated malaria by a village healthworker, were checked with a commercial RDT (Paracheck-Pf). The sensitivity, specificity, and positive and negative predictive values of this test, compared with the results of microscopy and two different definitions of clinical malaria, were then determined. The RDT was found to be 82.9% sensitive (with a 95% confidence interval of 78.0%-87.1%) and 78.9% (63.9%-89.7%) specific compared with the detection of parasites by microscopy. In the detection of clinical malaria, it was 95.2% (91.3%-97.6%) sensitive and 57.4% (48.2%-66.2%) specific compared with a general practitioner's diagnosis of the disease, and 100.0% (94.5%-100.0%) sensitive but only 30.2% (24.8%-36.2%) specific when compared against the fulfillment of the World Health Organization's (2003) research criteria for uncomplicated malaria. Among children aged 0-5 years, the cost of the 'test-and-treat' strategy, per episode, was about twice that of the 'treat-all' (U.S.$1.0. v. U.S.$0.5). In older subjects, however, the two strategies were equally costly (approximately U.S.$2/episode). In conclusion, for children aged 0-5 years in a high-transmission area of sub-Saharan Africa, use of the RDT was not cost-effective compared with the presumptive treatment of malaria with an ACT. In older patients, use of the RDT did not reduce costs. The question remains whether either of the strategies investigated can be made affordable for the affected population.

Quantifying the potential pathogens transmission of the blowflies (Diptera: Calliphoridae)

To quantify the potential capability of transporting and passing infective pathogens of some blowflies (Diptera: Calliphoridae), Mihályi's danger-index was calculated for seven species. The original equation was modified to include synanthropic information to discriminate between asynanthropic, hemisynanthropic, and eusynanthropic status. Three groups were recognized, of which Phaenicia cluvia and Musca domestica proved the flies with lowest index value (D = 2.93 and 3.00 respectively); Cochliomyia macellaria, Chrysomya albiceps and Sarconesia chlorogaster presented a significantly higher index value (p < 0.10; D = 4.28, 4.44 and 5.66 respectively) and C. megacephala, C. vicina and P. sericata appear to represent the heaviest potential sanitary risk with the highest index value (p < 0.10; D = 15.54, 16.88 and 12.49 respectively).

Acute schistosomiasis outbreak in the metropolitan area of Belo Horizonte, Minas Gerais: alert about the risk of unnoticed transmission increased by growing rural tourism

The present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of Belo Horizonte, state of Minas Gerais, Brazil. All individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. The apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. During a malacological survey at the site snails of the species Biomphalaria glabrata were found and tested positive for Schistosoma mansoni. All the patients live in the middle-class area of Barreiro, metropolitan area of Belo Horizonte and have medium grade school education. The difficulties in establishing the right diagnosis is expressed by the search for medical attention in 17 different medical facilities, the wide range of laboratory test and the inadequate treatment administration. A lack of knowledge about the disease was found in all groups studied. The booming rural tourism in endemic areas is identified as a probable risk factor for infection, especially for individuals of the non-immune middle and upper class parts of the society in urban centers. Special attention is given to a multidisciplinary approach to the complex issue of disease control and prevention.

Evaluation of indirect susceptibility testing of Mycobacterium tuberculosis to the first- and second-line, and alternative drugs by the newer MB/BacT system

In order to evaluate the Organon Teknika MB/BacT system used for testing indirect susceptibility to the alternative drugs ofloxacin (OFLO), amikacin (AMI), and rifabutin (RIF), and to the usual drugs of standard treatment regimes such as rifampin (RMP), isoniazid (INH), pyrazinamide (PZA), streptomycin (SM), ethambutol (EMB), and ethionamide (ETH), cultures of clinical specimens from 117 patients with pulmonary tuberculosis under multidrug-resistant investigation, admitted sequentially for examination from 2001 to 2002, were studied. Fifty of the Mycobacterium tuberculosis cultures were inoculated into the gold-standard BACTEC 460 TB (Becton Dickinson) for studying resistance to AMI, RIF, and OFLO, and the remaining 67 were inoculated into Lowenstein Jensen (LJ) medium (the gold standard currently used in Brazil) for studying resistance to RMP, INH, PZA, SM, EMB, and ETH. We observed 100% sensitivity for AMI (80.8-100), RIF (80.8-100), and OFLO (78.1-100); and 100% specificity for AMI (85.4-100), RIF (85.4-100), and OFLO (86.7-100) compared to the BACTEC system. Comparing the results obtained in LJ we observed 100% sensitivity for RMP (80-100), followed by INH - 95% (81.8-99.1), EMB - 94.7% (71.9-99.7), and 100% specificity for all drugs tested except for PZA - 98.3 (89.5-99.9) at 95% confidence interval. The results showed a high level of accuracy and demonstrated that the fully automated, non-radiometric MB/BacT system is indicated for routine use in susceptibility testing in public health laboratories.

Seasonal transmission of Leishmania (Leishmania) mexicana in the state of Campeche, Yucatan Peninsula, Mexico

In the Yucatan Peninsula, Mexico, localized cutaneous leishmaniasis (LCL) caused by Leishmania (Leishmania) mexicana is a typical wild zoonosis restricted to the forest, and humans are only accidentally involved. The transmission of L. (L.) mexicana has been related to the patient's occupation: "chicleros"(gum collectors) and agricultural workers. The objective of this study was to document L. (L.) mexicana seasonally of transmission in endemic areas of LCL in the state of Campeche, Yucatan Peninsula, Mexico. The timing of incidence of LCL in humans during 1993-1994, as well as the rate and time of infection in rodents and sand flies between February 1993 and March 1995 were analyzed. Rodents and sand flies were found infected between November and March, when men carried out their field activities and are exposed. Based on results analyzed, it is concluded that L. (L.) mexicana in the endemic area of LCL in the state of Campeche, Yucatan Peninsula, Mexico, presents a seasonal transmission restricted to the months of November to March. The knowledge of the timing of the transmission cycle in an endemic area of leishmaniasis is very important because intervention measures on the high-risk focus and population might be restricted.

Software de gestión de reclamaciones y denuncias on-line

Alta y gestión de reclamaciones de consumo a través de la web.

Release of extracellular particles by recombinant vaccinia virus over-expressing the major envelope protein p37K.

During the replication cycle of vaccinia virus, four different forms of viral particles are produced. The two extracellular enveloped forms, cell-associated enveloped virus and extracellular enveloped virus, are responsible for cell-to-cell transmission and long-range spread of infection both in vivo and in vitro. Despite the biological importance of the enveloped forms, the mechanism of envelopment and the components involved in this process have been analysed only recently. Therefore the individual steps and the rate-limiting factors of the envelopment process are still unknown. The protein p37K, an unglycosylated but acylated envelope protein of molecular mass 37 kDa, has been shown to be essential for envelopment. However, this study shows that over-expression of p37K by vaccinia virus recombinants reduces rather than increases the yield of infectious enveloped virus which is mainly due to the enveloped virions exhibiting a strongly diminished specific infectivity.

Trends in drug consumption and risk of transmission of HIV and hepatitis C virus among injecting drug users in Switzerland, 1993-2006

As a part of the HIV behavioural surveillance system in Switzerland, repeated cross-sectional surveys were conducted in 1993, 1994, 1996, 2000 and 2006 among attenders of all low threshold facilities (LTFs) with needle exchange programmes and/or supervised drug consumption rooms for injection or inhalation in Switzerland. Data were collected in each LTF over five consecutive days, using a questionnaire that was partly completed by an interviewer and partly self administered. The questionnaire was structured around three topics: socio-demographic characteristics, drug consumption, health and risk/preventive behaviour. Analysis was restricted to attenders who had injected drugs during their lifetime (IDUs). Between 1993 and 2006, the median age of IDUs rose by 10 years. IDUs are severely marginalised and their social situation has improved little. The borrowing of used injection equipment (syringe or needle already used by other person) in the last six months decreased (16.5% in 1993, 8.9% in 2006) but stayed stable at around 10% over the past three surveys. Other risk behaviour, such as sharing spoons, cotton or water, was reported more frequently, although also showed a decreasing trend. The reported prevalence of HIV remained fairly stable at around 10% between 1993 and 2006; reported levels of hepatitis C virus (HCV) prevalence were high (56.4% in 2006). In conclusion, the overall decrease in the practice of injection has reduced the potential for transmission of infections. However as HCV prevalence is high this is of particular concern, as the current behaviour of IDUs indicates a potential for further spreading of the infection. Another noteworthy trend is the significant decrease in condom use in the case of paid sex.

Active transmission of human chagas disease in Colima Mexico

Despite efforts to eradicate American trypanosomiasis (AT) and Chagas disease from the Americas, there are still areas of active transmission that can eventually become a source of reinfection in previously controlled regions. Mexico could be one of those areas, where there are no formal preventive control programs despite the presence of communities infested by Triatominae bugs infected with Trypanosoma cruzi. This study explored the prevalence of T. cruzi infection in 405 habitants of 17 communities in the state of Colima, on the Pacific Mexican coast, through a seroepidemiological probabilistic survey. The results revealed a point seroprevalence of 2.4% positive for anti-T. cruzi. In addition, 2 clinical cases of chronic and 2 of acute Chagas disease were detected in the explored communities. These findings confirm the risk of active transmission of AT in Western Mexico, especially in rural and suburban communities infested with intra-domestic triatominae, where control programs should be implemented.

Phlebotomine sand flies in Porteirinha, an area of American visceral leishmaniasis transmission in the State of Minas Gerais, Brazil

A study of the phlebotomine sand fly fauna was carried out in an endemic area of American visceral leishmaniasis (AVL) in the municipality of Porteirinha, in the Brazilian state of Minas Gerais. Captures were performed with CDC light traps in 7 districts, 5 days per month, during 2 consecutive years (January 2000 to December 2001). A total of 3240 sand flies were captured and identified. Sixteen species were found, among which 15 belonged to the genus Lutzomyia and one to the genus Brumptomyia. Lutzomyia longipalpis, a proven vector of AVL, was the predominant species (71.85%) throughout the time period. The interference of climatic factors (temperature, humidity, and rainfall) over the populational dynamics of the sand flies was determined. Statistical analysis of the data showed a significant correlation among the number of phlebotomine sand flies collected, rainfall, and humidity, whereas the effect of temperature was negligible, in that particular region. The amount of collected phlebotomine, the number of human cases, and the prevalence of canine AVL in the districts of Porteirinha are discussed.

Rabies neutralizing antibody detection by indirect immunperoxidase serum neutralization assay performed on chicken embryo related cell line

The aim of this study was to evaluate the indirect immunoperoxidase virus neutralization (IPVN) and mouse neutralization test (MNT) to detect antibodies against rabies virus from vaccinated dogs and cattle. The IPVN was set up for the ability to measure 0.5 International Units/ml (IU) of antibody required by the World Health Organization and the Office International des Epizooties as the minimum response for proof of rabies immunization. IPVN was developed and standardized in chicken embryo related (CER) cell line when 141 dog and 110 cattle sera were applied by serial five-fold dilutions (1:5, 1:25, 1:125) as well as the positive and negative reference controls, all added in four adjacent wells, of 96-well microplates. A 50 µl amount of CVS32 strain dilution containing 50-200 TCID50/ml was mixed to each serum dilution, and after 90 min 50 µl of 3 x 10(5) cells/mlcell suspension added to each well. After five days of incubation, the monolayers were fixed and the IPVN test performed. The correlation coefficient between the MNT and IPVN performed in CER cells was r = 0.9949 for dog sera (n = 100) and r = 0.9307 for cattle sera (n = 99), as well as good specificity (94.7%), sensitivity (87.5%), and agreement (96.6%) were also obtained. IPVN technique can adequately identify vaccinated and unvaccinated animals, even from low-responding vaccinated animals, with the advantage of low cost and faster then MNT standard test.

Alimentation et transmission mère-enfant

Bien que de nombreux auteurs aient traité, dans la relation mère-enfant, l'importance de l'alimentation, (et donc du rapport à la nourriture) et l'interprétation des troubles qui peuvent en résulter, nous proposons dans cet article de constituer une vérification expérimentale d'une question spécifique: que se transmet-il entre mère et enfant dans le contexte alimentaire ? Au travers d'une recherche multidisciplinaire alliant socio-anthropologie et psychologie, nous avons constitué et étudié un recueil de données couplant représentations socioculturelles, histoires alimentaires personnelles ainsi qu'observations et analyses de la qualité des interactions alimentaires auprès d'une population de mères françaises et leur enfant (sain) âgé de 1 à 2 ans.

Drug susceptibility of Brazilian strains of Mycobacterium bovis using traditional and molecular techniques

Transmission of Mycobacterium bovis from cattle to humans has been reported and can cause tuberculosis (Tb) and a problem in certain risk populations. Therefore, knowledge of resistance of M. bovis towards antibiotics used for therapy of human Tb could help avoiding cure delay and treatment cost increase when dealing with drug resistant organisms. We therefore evaluated the susceptibility of M. bovis isolates towards streptomycin, isoniazide, rifampicin, ethambutol, and ethionamide, the first line antibiotics for human Tb. Therefore, 185 clinical samples from cattle with clinical signs of tuberculosis were processed and submitted to culturing and bacterial isolates to identification and drug susceptibility testing using the proportion method. Among 89 mycobacterial strains, 65 were identified as M. bovis and none were resistant to any of the antibiotics used. Confirmation of present results by future studies, enrolling a large number of isolates and designed to properly represent Brazilian regions, may favor the idea of using isoniazide preventive therapy as part of a Tb control strategy in special situations. Also, nucleic acids from bacterial isolates were submitted to rifoligotyping, a recently described reverse hybridization assay for detection of mutations causing resistance towards rifampicin. Concordance between the conventional and the molecular test was 100%, demonstrating the use of such methodology for rapid evaluation of drug susceptibility in M. bovis.

24 Hours in the Life of HIV-1 in a T Cell Line.

HIV-1 infects CD4+ T cells and completes its replication cycle in approximately 24 hours. We employed repeated measurements in a standardized cell system and rigorous mathematical modeling to characterize the emergence of the viral replication intermediates and their impact on the cellular transcriptional response with high temporal resolution. We observed 7,991 (73%) of the 10,958 expressed genes to be modulated in concordance with key steps of viral replication. Fifty-two percent of the overall variability in the host transcriptome was explained by linear regression on the viral life cycle. This profound perturbation of cellular physiology was investigated in the light of several regulatory mechanisms, including transcription factors, miRNAs, host-pathogen interaction, and proviral integration. Key features were validated in primary CD4+ T cells, and with viral constructs using alternative entry strategies. We propose a model of early massive cellular shutdown and progressive upregulation of the cellular machinery to complete the viral life cycle.