Secondary dengue infection in immunocompetent murine model leads to heart tissue damage.

Dengue, considered the most important arthropod-borne viral disease affecting humans, is transmitted by the bite of mosquitoes of the genus Aedes and caused by one of the four distinct serotypes of dengue virus (DENV-1, -2, -3 and -4). Infection with one of the four serotypes provides lifelong homotypic immunity. However, immunity against the heterologous serotypes is transient. As a consequence, secondary infection may lead to severer manifestations due to cross-reactivity of antibodies and T-cells. Over 500,000 people are hospitalized every year and around 2,5 million, living in endemic areas, are at risk of infection. Given the background, the development of vaccines and anti-DENV drugs is of the utmost importance, as is the characterization of an animal model for testing them. The purpose of this study was to investigate ultrastructural alterations caused by DENV secondary infection in BALB/c mice heart. To achieve our goal, six BALB/c mice were infected with DENV-1 and, 4 months later, reinfected with DENV-2. Uninfected mice were used as negative controls. Heart samples were collected and processed for ultrastructural and histopathological analysis. Our results showed edema, endothelium activation characterized by the presence of transport vesicles, free platelets in interstitium, mitochondria presenting rarefied matrix and degenerated cristae, and disorganization of muscle fibers. These results point not only to BALB/c mice susceptibility to DENV infection, but also to the fact that, although it is not an often reported occurrence, dengue can lead to heart damage. Keywords: dengue; experimental model; reinfection; BALB/c mice.

Crystallization of bothrombin, a fibrinogen-converting serine protease isolated from the venom of Bothrops jararaca.

Bothrombin, a snake-venom serine protease, specifically cleaves fibrinogen, releasing fibrinopeptide A to form non-crosslinked soft clots, aggregates platelets in the presence of exogenous fibrinogen and activates blood coagulation factor VIII. Bothrombin shares high sequence homology with other snake-venom proteases such as batroxobin (94% identity), but only 30 and 34% identity with human alpha-thrombin and trypsin, respectively. Single crystals of bothrombin have been obtained and X-ray diffraction data have been collected at the Laboratorio Nacional de Luz Sincrotron to a resolution of 2.8 A. The crystals belong to the space group P2(1)2(1)2(1), with unit-cell parameters a = 94.81, b = 115.68, c = 155.97 A.

[An introductory vision of the quality of life in work]. / Visão introdutória de qualidade de vida no trabalho.

The present paper refers to an introductory study about "Quality of work life" (QWL), subject which requires a growing importance in certain organizations. At first it is a discussion on the origin of this movement and its conceptualization by some authors. Afterwards two approaches to QWL are exposed--the classical and the situational. This is a classification used by the authors themselves to emphasize the original, conventional concept of QWL and to differentiate it from the second approach which is really situational and which has a broader sense, adapting to reality and to the context of the organization. The paper concludes with a reflection on the future courses of organizations, its human resources and QWL.

Invasive pulmonary aspergillosis after near-drowning.

After near-drowning following a car accident, a 27-year-old man developed severe ARDS. Six days later Aspergillus fumigatus was isolated in his sputum, and invasive pulmonary aspergillosis developed thereafter. Aspergillus titre increased, and chest tomograms revealed cavities in both lungs. The treatment consisted essentially of Amphotericin B and 5 fluorocytosine, intravenously and by inhalation, intensive postural drainage and mechanical ventilation with PEEP. After 41 days he was cured and discharged from the ICU. Six months later he returned to his job and clinical examination was normal.

Influence of some factors on the fit of cemented crowns.

In the study, cast gold crowns were cemented similar to methods used for patients. Conclusions were that: 1. Fresh cement painted with a camel brush in the part of the crown to be cemented promotes a better fit than when the crown is completely filled with cement. 2. Mechanical vibration of the crown at cementation promotes a better fit. 3. Venting the crown, an internal relief by acid etching, or a combination of both these procedures improve the seating of the crown during cementation. 4. The association of one or numerous variables used in this study considerably improves the fit of the cemented crown.

Influence of pressure and vibration during cementation.

Vibration, applied at the beginning of cementation, improves the fit of MOD inlays and cast complete crowns when they are compared to the same castings cemented without vibration. The Medart pressure applicator produced better adaptation. Orange wood blocks and Burlew disks produced similar results. They were less efficient than the Medart pressure applicator. Cotton rolls resulted in the highest fit discrepancy.

Fluoride release and physical properties of a fluoride-containing amalgam.

1. The amount and percentage of fluoride released from amalgam were less for the 1:1.6 alloy/mercury ratio than for the 1:1 ratio. 2. Higher fluoride concentrations resulted in a greater quantity but lower percentage of fluoride released from the amalgam. 3. Longer immersion times resulted in a greater amounts and percentages of released fluoride. However, the fluoride released per hour decreased with immersion time. 4. Immersion of the amalgam in lactic acid caused a greater release of fluoride than immersion in distilled water. 5. Disintegration of the amalgam was greater in lactic acid than in distilled water. The contribution of calcium fluoride to weight loss was greater in water than in lactic acid, indicating a corrosive effect for lactic acid. 6. The higher calcium fluoride content (2 per cent) decreased the compressive strength of the amalgam but did not alter the dimensional change.

Changes in physical properties of joined gypsum fragments.

(1) The dimensional change in joined fragments of gypsum models was small. The highest percentage occurred with zinc phosphate cement. (2) The cyanoacrylate cements produced the strongest bonds. Mendent Formula VI and the epoxy cement were least effective. (3) The bond strength was generally greater after 24 hours. The exceptions were Mendent Formula VI and zinc phosphate cement. (4) Different gypsum products responded differently to bonding agents. Some are superior for plaster of Paris; others for artificial dental stone.

Tissue reaction to dispersion alloy amalgam.

Dental amalgam implanted in rat connective tissue is injurious for the first 16 days. At 32 days, the implanted amalgam is tolerated. The increased copper content of Dispersalloy did not evoke a more serious response of the connective tissue than Fine Cut or Spheraloy amalgam.