Extraction and characterization of collagen from the skin of Amazonian freshwater fish pirarucu

The need to fully exploit fishing resources due to increasing production and consequent waste generation requires research to promote the sustainability of the fishing industry. Fish waste from the industry is responsible for relevant environmental contamination. However, these raw materials contain high amounts of collagen and other biomolecules, being attractive due to their industrial and biotechnological applicability. Thus, to reduce the waste from pirarucu (Arapaima gigas) processing, this study aimed to obtain collagen from pirarucu skin tissue. The extraction process used 0.05 M sodium hydroxide, 10% butyl alcohol, and 0.5 M acetic acid, with extraction temperature of 20°C. The obtained yield was 27.8%, and through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), it was determined that the collagen obtained was type I. This study showed that collagen solubility was highest at pH 3 and the lowest solubility was at concentrations of 3% sodium chloride. The denaturation temperature of collagen was 38.1°C, and its intact molecular structure was observed using the Fourier transform infrared spectrophotometry technique with an absorption radius of 1. The results showed that it was possible to obtain collagen from pirarucu skin at 20°C, which has the typical characteristics of commercial type I collagen. In conclusion, the procedures used may be considered to be an interesting alternative for collagen extraction, a new product obtained from the processing of fish waste.

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol.

Proconvulsant effects of high doses of venlafaxine in pentylenetetrazole-convulsive rats

Venlafaxine, an atypical antidepressant drug, has been used to treat several neurological disorders, presenting excellent efficacy and tolerability. Clinical seizures after venlafaxine treatment have occasionally been reported when the drug was used at very high doses or in combination with other medications. The aim of the present study was to investigate the convulsant effects of venlafaxine in rats under controlled laboratory conditions. Adult male Wistar rats (8 per group) receiving venlafaxine or saline at the doses of 25-150 mg/kg were subjected 30 min later to injections of pentylenetetrazole at the dose of 60 mg/kg. The animals receiving 75, 100 and 150 mg/kg venlafaxine presented increased severity of convulsion when compared to controls (P = 0.02, P = 0.04, and P = 0.0004, respectively). Indeed, an increased percentage of death was observed in these groups (50, 38, and 88 percent, respectively) when compared to the percentage of death in the controls (0 percent). The group receiving 150 mg/kg showed an reduction in death latency (999 + or - 146 s) compared to controls (1800 + or - 0 s; cut-off time). Indeed, in this group, all animals developed seizures prior to pentylenetetrazole administration. Surprisingly, the groups receiving venlafaxine at the doses of 25 and 50 mg/kg showed a tendency towards an increase in the latency to the first convulsion. These findings suggest that venlafaxine at doses of 25 and 50 mg/kg has some tendency to an anticonvulsant effect in the rat, whereas doses of 75, 100 and 150 mg/kg presented clear proconvulsant effects in rats submitted to the pentylenetetrazole injection. These findings are the first report in the literature concerning the role of venlafaxine in seizure genesis in the rat under controlled conditions

Erros de confeccao das lentes progressivas e suas manifestacoes clinicas. / Manufacturing errors of progressive lenses and its clinical manifestations

Estudando uma amostra de 176 casos de portadores de lentes progressivas, o autor, mostrando a eficacia do seu metodo de exames destas lentes, correlaciona os defeitos encontrados as queixas dos seus portadores

Aspectos conceituais da refratometria introducao a logica de refracao ocular. / Conceptual aspects of the refractometry: introduction to the ocular refraction logic

O autor estabelece conceitos sobre a variabilidade da refratometria ocular utilizando metodos da logica formal

Modelo de formacao de imagens nas lentes progressivas. / Optical model for images formation in the progressive lenses

O modelo apresentado pelo autor, permite conhecer certas especificidades das lentes progressivas como centros opticos prismados, diferenca entre as lentes progressivas concavas e convexas, variabilidade das zonas de progressao e os efeitos das descentracoes

Aspecto histologico do epitelio do pterigio. / Histologic aspects of the epithelium of pterygium

O epitelio do pterigio apresenta, como principal alteracao, a metaplasia escamosa. Ela e tambem predominante e parece uma sua caracteristica. Ha comumente pigmentacao melanica assim como pseudo-glandula. A presenca de glandulas, mesmo nao sendo muito frequente, nao pode ser considerada como anomalia. A presenca de displasia, relativamente alta, sugere a observacao do pterigio como campo potencial de neoplasias

Prebiopia: conceitos atuais. / Presbyopia current concepts

O Autor estudou os componentes da acomodacao sob os aspectos embriologicos, anatomicos e fisiologicos. Atualizou o conceito de Weale sobre o carater multifatorial da acomodacao e acrescentou o papel do vitreo baseado nos achados de Coleman. Foram assinalados dados sobre a manifestacao e a evolucao da presbiopia na nossa regiao. Dados clinicos levaram o autor a sustentar o carater limitado da atuacao do corpo ciliar atribuindo ao cristalino papel preponderante na acomodacao