Clinical forms of Trypanosoma cruzi infected individuals in the chronic phase of Chagas disease in Puebla, Mexico

In Mexico, despite the relatively high seroprevalence of Trypanosoma cruzi infection in humans in some areas, reported morbidity of Chagas disease is not clear. We determined clinical stage in 71 individuals seropositive to T. cruzi in the state of Puebla, Mexico, an area endemic for Chagas disease with a reported seroprevalence of 7.7%. Diagnosis of Chagas disease was made by two standardized serological tests (ELISA, IHA). Individuals were stratified according to clinical studies. All patients were submitted to EKG, barium swallow, and barium enema. Groups were identified as indeterminate form (IF) asymptomatic individuals without evidence of abnormalities (n = 34 cases); those with gastrointestinal alterations (12 patients) including symptoms of abnormal relaxation of the lower esophageal sphincter and absent peristalsis in the esophageal body, grade I megaesophagus, and/or megacolon; patients with clinical manifestations and documented changes of chronic Chagas heart disease who were subdivided as follows: mild (8 patients) - mild electrocardiographic changes of ventricular repolarization, sinus bradychardia); moderate (6 patients) - left bundle branch block, right bundle branch block associated with left anterior fascicular block); severe (8 patients) - signs of cardiomegaly, dilated cardiomyopathy); and the associated form (3 cases) that included presence of both cardiomyopathy and megaesophagus. These data highlight the importance of accurate evaluation of the prevalence and clinical course of Chagas disease in endemic and non-endemic areas of Mexico.

Understanding mechanisms and the role of differentiation in pathogenesis of Toxoplasma gondii: a review

Parasite differentiation from proliferating tachyzoites into latent bradyzoites is central to pathogenesis and transmission of the intracellular protozoan pathogen Toxoplasma gondii. The presence of bradyzoite-containing cysts in human hosts and their subsequent rupture can cause life-threatening recrudescence of acute infection in the immunocompromised and cyst formation in other animals contributes to zoonotic transmission and widespread dissemination of the parasite. In this review, we discuss the evidence showing how the clinically relevant process of bradyzoite differentiation is regulated at both transcriptional and post-transcriptional levels. Specific regulatory factors implicated in modulating bradyzoite differentiation include promoter-based cis-elements, epigenetic modifications and protein translation control through eukaryotic initiation factor -2 (eIF2). In addition to a summary of the current state of knowledge in these areas we discuss the pharmacological ramifications and pose some questions for future research.

Spontaneous perforation of gallbladder with intrahepatic biloma formation: sonographic signs and correlation with computed tomography

Spontaneous perforation of gallbladder is a severe and infrequent complication of acute cholecystitis that requires early and accurate diagnosis. Concomitant development of intrahepatic collections is rarely observed in such cases. The present report emphasizes the relevance of imaging studies in this setting, describing the typical sonographic and tomographic findings for the diagnosis of such condition.

Conhecimento escolar em química: processo de mediação didática da ciência

xThe aim of this article is to present a contribution of the school knowledge research to Chemistry Teaching. The object of research is school knowledge on physical sciences, considering the existence of a rupture between scientific knowledge and everyday knowledge. The differences between analogies and metaphors and the process of didactic mediation were thoroughly examined. The conclusion is that the process of didactic mediation is built on their own cognitive configurations, which not always make public the private scientific knowledge to certain social groups.

Descomposicion termica del diperoxido de pinacolona (3,6-diterbutil-3,6-dimetil-1,2,4,5-tetraoxaciclohexano) en solución de 2-metoxietanol

The thermal decomposition reaction of pinacolone diperoxide (DPP; 0.02 mol kg-1) in 2-methoxyethanol solution studied in the temperature range of 110.0-150.0 °C, follows a first-order kinetic law up to at least 50% DPP conversion. The organic products observed were pinacolone, methane and tert-butane. A stepwise mechanism of decomposition was proposed where the first step is the homolytic unimolecular rupture of the O-O bond. The activation enthalpy and activation entropy for DPP in 2-methoxyethanol were calculated (deltaH# = 43.8 ± 1.0 kcal mol-1 and deltaS# = 31.9 ± 2.6 cal mol-1K-1) and compared with those obtained in other solvents to evaluate the solvent effect.

Produção, purificação, clonagem e aplicação de enzimas líticas

Lytic enzymes such as beta-1,3 glucanases, proteases and chitinases are able to hydrolyse, respectively, beta-1,3 glucans, mannoproteins and chitin, as well as the cell walls of many yeast species. Lytic enzymes are useful in a great variety of applications including the preparation of protoplasts; the extraction of proteins, enzymes, pigments and functional carbohydrates; pre-treatment for the mechanical rupture of cells; degradation of residual yeast cell mass for the preparation of animal feed; analysis of the yeast cell wall structure and composition; study of the yeast cell wall synthesis and the control of pathogenic fungi. This review presents the most important aspects with respect to lytic enzymes, especially their production, purification, cloning and application.

A formação do pós-graduando em química para a docência em nível superior

The article presents a brief analysis on chemistry post-graduate students' perception on teaching in higher education. This study was done based on the context of students' formation in chemistry post-graduate programs and makes suggestions on how to improve the formation process of post-graduate students in order to decrease the rupture between teaching and research in chemistry post-graduate programs.

Concepções e ações de formadores de professores de química sobre o estágio supervisionado: propostas brasileiras e portuguesas

The purpose of this paper is to investigate lecturers'actions and conceptions about pre-service teaching practices in chemistry. In this sense, it takes into account several theoretical references concerned with teacher education, which support the qualitative analysis of 18 interviews, gathered with 14 brazilian and 4 portuguese lecturers. Results reveal that the pre-service teaching practices in chemistry have been performed far from a technical approach, showing a paradigmatic rupture and presenting another logic related with teacher education in chemistry, which have improved the comprehension of the teachers' real practices, since these have been shaped by complex and unprescribed factors.

Efficient synthesis of benzothiazine and acrylamide compounds

This article describes the synthesis of the new (2Z)-2-(4-methoxybenzylidene)-6-nitro-4H -benzo[1,4]thiazin-3-one, (2Z)-2-(4-methoxybenzylidene)-4-methyl-6-nitro-4H-benzo[1,4]thiazin-3-one, (2Z)-6-amino-2-(4-methoxybenzylidene)-4H -benzo[1,4]thiazin-3-one, (2Z)-6-butylamino-2-(4-methoxybenzylidene)-4-methyl-4H-benzo[1,4]-thiazin-3-one and (2E)-N-alkyl-N-(2-hydroxy-5-nitrophenyl)-3-phenylacrylamides and the spectroscopic data. The arylidenebenzothiazine compounds were prepared using the Knoevenagel condensation with substituted benzaldehydes in the presence of sodium methoxide in DMF. The presence of a nitro substituent in the 4-position, water and a slightly acid reaction medium in this condensation caused the rupture of the benzothiazine ring and subsequent formation of the phenylacrylamide compounds. A crystallographic data was presented for (2E)-3-(4-bromophenyl)-N-dodecyl-N -(2-hydroxy-5-nitrophenyl) acrylamide.

NANOPARTICLES OF TUNGSTEN AS LOW-COST MONOMETALLIC CATALYST FOR SELECTIVE HYDROGENATION OF 3-HEXYNE

Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surface. The effects of the content of W nanoparticles and reaction temperature on activity and selectivity for the partial hydrogenation of 3-hexyne, a non-terminal alkyne, were assessed under moderate conditions of temperature and pressure. The monometallic catalysts prepared were found to be active and stereoselective for the production of (Z )-3-hexene, had the following order: 7.1WN/A > 8.5 WN/A ≥ 4.5 WN/A. Additionally, the performance of the synthesized xWN/A catalysts exhibited high sensitivity to temperature variation. In all cases, the maximum 3-hexyne total conversion and selectivity was achieved at 323 K. The performance of the catalysts was considered to be a consequence of two phenomena: a) the electronic effects, related to the high charge of W (+6), causing an intensive dipole moment in the hydrogen molecule (van der Waals forces) and leading to heterolytic bond rupture; the H+ and H- species generated approach a 3-hexyne adsorbate molecule and cause heterolytic rupture of the C≡C bond into C- = C+; and b) steric effects related to the high concentration of WO3 on 8.5WN/A that block the Al2O3 support. Catalyst deactivation was detected, starting at about 50 min of reaction time. Electrodeficient W6+ species are responsible for the formation of green oil at the surface level, blocking pores and active sites of the catalyst, particularly at low reaction temperatures (293 and 303 K). The resulting best catalyst, 7.1WN/A, has low fabrication cost and high selectivity for (Z )-3-hexene (94%) at 323 K. This selectivity is comparable to that of the classical and more expensive industrial Lindlar catalyst (5 wt% Pd). The alumina supported tungsten catalysts are low-cost potential replacements for the Lindlar industrial catalyst. These catalysts could also be used for preparing bimetallic W-Pd catalysts for selective hydrogenation of terminal and non-terminal alkynes.

Resultados científicos do cruzeiro do "Baependi" e do "Vega" à Ilha da Trindade: contribuição para o conhecimento da plataforma insular da Ilha da Trindade

The oceanographic work realized during 10 days in the surroundings of the eruptive island of Trindade, 20º30'36" lat. S - 29º19'26" long. W, had as principal aim the determination of the insular plateau, whose knowledge was very insufficient. Thus were established some oceanographic stations and sounding lines were realized by means of an echobathymeter whose responses were initially verified with mechanical soundings obtaneid by means of a Thomson sounder. The insular plateau is very narrow and exhibits a sudden fall between the 100 and 120 m. depth line at 740 m. - 2950 m. from the coast. Its greatest depth is of 108,30 m. and its mean inclination is of 8,12%. The plateau of the island of Trindade is separated from that of the neighbouring group of Martim Yaz by great depths. The bottoms are rocky near the coast, the blocks having been produced by the rupture of the magmatic mass of the island. Further away from the coast, the size of the rocks gradually diminishes up to the fine sand thickness. In the litoral zone there are abundant tufts of living Lithothamnion with a rich associated flora and fauna, which partly covers the rocks themselves. Further off at sea, the spheres of the dead alga with its commensals are cimented together by sedimentation. The spheres are further broken up and become an integrating part of the sand. The results of the physical and chemical analyses of the sand bottoms are shown in tables 2 and 3. The coast is either of abrupt rocky walls falling down to sea level, or of shores, made of pebbles or of sand. Anyhow, there are frequently Lithothamnion terraces slightly inclinated towards the bottom (chemical analysis table 1).

Early detection of injuries in leaves of Clusia hilariana Schltdl. (Clusiaceae) caused by particulate deposition of iron

This study aims to evaluate the prognostic value of microscopic parameters of asymptomatic leaves of Clusia hilariana Schltdl. subjected to particulate deposition of iron (2.14 mg cm-2 day-1) for 45 consecutive days. Samples of young and expanded leaves without symptoms were collected and subjected to light and scanning electron microscopy techniques. The height of the epidermal cells on both surfaces of the leaf and the thickness of the hypodermis, the chlorophyll parenchyma, and the leaf blade were measured. Micromorphological injury occurred in the abaxial surface of young leaves and on both surfaces of expanded leaves. Erosion of the epicuticular wax and cuticle rupture were frequent on the adaxial surface, while on the abaxial surface of both leaves there was a loss of sinuosity on the anticlinal wall of the epidermal cells, stomatal deformity and obstruction. Micromorphometric alterations were seen in all leaf tissues except in the height of epidermic cells, probably due to the thick cuticle and prominent cuticular flanges. The highest difference in thickness of the leaf blade was seen in young leaves of plants subjected to SPMFe, indicating greater sensibility to particulate iron in comparison to the expanded leaves. The micromorphological and micromorphometric alterations in the leaf blade of Clusia hilariana Schltdl. showed the prognostic potential of these tools on the evaluation of impacts caused by the deposition of particulate matter, especially in the 'Restinga' natural vegetation, where the exposure is increasing due to the presence of iron ore industry in their surroundings.

Mechanical properties of castor beans subject to different drying temperatures aiming to disrupt the bean coat

In castor oil extraction process, the bean coat is abrasive to the equipment and releases substances that modify the oil color, reducing its quality. A potential solution would be to run the extraction by compressing only the endosperm. Due to lack of information, the objective of this study was to evaluate the influence of forced air drying at 40, 60, 80 and 100 ºC and farmyard drying, in the mechanical properties of the beans, aiming to break the bean coat. Castor beans were subjected to compression tests, in two perpendicular directions, at a strain rate of 0.6 mm.s-1. Average values of force, deformation energy, strain, all at rupture, and stiffness were used to evaluate the effects of dehydration. It was observed that the heat treatments did not alter the mechanical properties of castor beans, the strain and stiffness values discriminate the differences between the directions and had the lowest coefficients of variation. It was concluded that forced air drying, more costly than farmyard drying, does not bring benefits to the decortication. However, regardless the heat treatment used, the mechanical stress lengthwise is the most suitable to promote decortication.

Cisto esplênico não-parasitário e não-neoplásico

The authors present a rare case of pathology from spleen, a nonparasitic, non-neoplastic splenic cyst, in an adult male patient without a previous history of abdominal trauma. Principal clinical findings were pain in left upper quadrant, nausea, regurgitation and precocious satiation. On investigation, ultrasonography and CT scan showed an expansive lesion in the spleen, compressing the stomach. Surgical procedure was splenectomy and a microscopical examination revealed a non- parasitic, non-neoplastic splenic cyst. Splenic cysts are usually benigns, but surgical remotion is necessary when they are symptomatic or exist risk of rupture. In this report is presented the classification of splenic cysts, clinical manifestations, diagnostics methods and discussed their surgical treatment.

Pseudo-aneurisma gigante de artéria axilar esquerda

A case of a gunshot of the left axilary artery with a giant pseudoaneurism formation with sixteen years of evolution is presented. The 61- years-old male patient present since them a small assintomatic tumoration in infraclavicular localization. In the last eight months the tumor became symptomatic and volumous, reaching 20 cm in diameter, with signals of infection and imminent rupture. The patient was operated on with ligature of the axilary artery and evacuation of the pseudoaneurysm. The surgical handling and endovascular therapeutic options available in the present time are discussed. A short review about the disease as well as a bibliographic update are present. The authors also call attention for the necessity of a correct management of the vascular injures in the event of the first management.