Ultrastructural analysis and residual DNA evaluation of rabbit vein scaffold

Abstract Purpose: To investigate the ultrastructural characteristics and analysis of residual DNA in scaffold models, produced with decellularized vena cava in an experimental model with rabbits. Methods: Three groups were created for ultrastructural and residual DNA analysis: group 1 - control, consisting of samples of vena cava in natura; group 2 - SD, consisting of vein fragments submitted to 2% sodium deoxycholate decellularization by shaking (160rpm - Shaker News Brunswick Scientific®) for 1 hour at controlled temperature shaker at 37°C; group 3 - SDS, consisting of vein fragments submitted to 1% sodium dodecyl sulfate decellularization under the same previous condition, for 2 hours. Results: The ultrastructural matrix of the blood vessel maintained its vintegrity after either decellularization models. The results of the two quantification methods demonstrated a significant decrease in the DNA content of the decellularized vena cava samples as compared to the control samples and, differed statistically from each other, p <0.05. Conclusion: The 2% DS protocol for vein decellularization, in this experimental model, was considered the best protocol because it presented less amount of residual DNA without causing substantial destruction of the extracellular matrix.

Biología molecular y medicina: conceptos básicos / Molecular biology and medicine: basic concepts

Through the advancements of molecular genetics, physicians and researchers are in an extraordinary period of study concerning the molecular basis of medicine. Molecular biology is making a tremendous impact on both diagnosis and treatment of diseases through the clinical introduction of molecular methods. These techniques, restricted for many years to basic biological research, include the polymerase chain reaction, DNA and protein electrophoresis, cloning of genes into viral or bacterial vectors and methods to rapidly sequence DNA and identify mutations. In this article the authors attempt to provide basic concepts on these themes for the non-trained physicians in order to help them to understand recent developments and foresee their future implications

Estudo morfométrico e bioquímico do crescimento das glândulas sublinguais do rato durante a vida pós-natal / Morphometrical and biochemical study of the rat sublingual glands growth during postnatal period

As glândulas sulinguais do rato albino crescem marcadamente nos primeiros 40 dias de vida pós-natal. Na presente pesquisa estudamos a participaçäo da atividade proliferativa e do aumento do volume celular neste crescimento. A atividade proliferativa foi medida pelo aumento do DNA total avaliado bioquimicamente e o aumento do volume celular foi determinado por métodos morfométricos. A análise dos resultados mostrou que: a) o DNA aumentou 717 por cento (P < 0,01) no período de 2 a 40 dias de vida pós-natal; b) o volume das células acinosas mucosas exibiu flutuaçöes estatisticamente näo significativas até o 15§ dia, sofrendo, a partir daí, um aumento de 101 por cento (P < 0,05) até o 40§ dia; c) o volume das células das semiluas serosas mostrou decréscimo de 27 por cento (P < 0,05) no período de 10 a 15 dias, seguido de aumento de 71 por cento (P < 0,05) no período de 15 a 30 dias. Esses resultados indicam que o aumento significativo de massa de glândulas sublinguais do rato durante o período inicial de vida pós-natal, ocorreu principalmente por atividade proliferativa, e também, com menor participaçäo, por aumento de volume celular, notadamente das células acinosas mucosas.

Análisis ultraestructural e inmunocitoquímico del complejo sinaptonémico al inicio de la sinapsis / Ultraestructual analysis and immunocytochemical of synaptonemal complex at begging of synapsis

Los complejos sinaptonémicos (CSs) son estructuras nucleares específicas de las meiosis. Juegan un papel central en el apareamiento de cromosomas homólogos, se consideran esenciales en los eventos de crossing over y la segregación cromosómica durante la primera división meiótica. Cuando finaliza su ensamble en el estadio paquiteno, cada complejo sinaptonémico se extiende a lo largo del bivalente uniendo sus extremos a la envoltura nuclear. Los CSs se caracterizan por la presencia de dos elementos laterales y una región central. Los elementos laterales son paralelos y equidistantes. La cromatina de los cromosomas homólogos, se unen en una serie de asas a estos elementos. La región central se localiza entre los elementos laterales. Está formada por las fibrillas latero-mediales y el elemento medial. Las primeras se orientan perpendicularmente al eje longitudinal de CS y conectan los elementos laterales con el elemento medial. Los nódulos de recombinación juegan un papel activo en los procesos de recombinación y formación de quiasmas, se asocian a intervalos con la región central entre los cromosomas homólogos. La localización y función de los ácidos nucleicos en la formación y apareamiento del complemento sinaptonémico es poco conocida, por lo que se buscan alternativas metodológicas para resolver este tipo de problemas. En el presente trabajo se estudió la distribución de ADN en ovocitos de pollo en citeno utilizando técnicas para icroscopía electrónica de inmuno-oro. Además se emplearon técnicas citoquímicas como: contraste preferencial para ADN o preferencial para ribonucleoproteínas (RNPs). La combinación de tinción preferencial para RNPs e inmunolocalización de ADN nos demuestran que la cromatina se acumula conujuntamente con las ribonucleoprotéinas en los elementos laterales no apareados y la presencia de numerosas fibrillas RNPs distribuidas laxamante alrededor de los elementos laterales. Se encontraron nódulos de recombinación entre los elementos laterales durante el apareamiento, estos nódulos son PTA positivos lo que nos indica la presencia de ADN en éstos y por lo tanto la presencia de ADN entre los elementos laterales. La presencia de un puente de fibrillas marcadas con oro coloidal (ADMN) uniendo a los elementos laterales no apareados, sugeriría al ADN como una especie de macromolécula formadora de sitios de sinapsis

Eurytrema coelomaticum: influence of the infection on the reproduction and nucleic acids contents in the albumen gland and ovotestis of Bradybaena similaris

The number of eggs laid per snail in Bradybaena similaris and the nucleic acids (DNA and RNA) in the albumen gland and ovotestis were quantified in snails infected with sporocysts of the digenetic trematode Eurytrema coelomaticum. The total number of eggs laid per mollusc was reduced by 96.32 por cento at the end of the larval development. The DNA concentration increased by 700 por cento and the RNA concentration was reduced by 8,38 por cento by the time when the daughter sporocysts of E. coelomaticum were released from B. similaris. The relation between these values and the inhibition of the reproduction observed in infected molluscs is discussed.

The effect of discontinuous Percoll gradient centrifugation on sperm morphology and nuclear DNA normality.

To determine the improvement of sperm morphology and sperm nuclear DNA normality after discontinuous Percoll gradients preparation, sperm morphology and sperm nuclear DNA normality from 157 semen samples from 45 donors and 63 male partners of infertile couples were assessed before and after discontinuous Percoll gradients preparation. In semen samples, about 67.5 per cent of the nuclei exhibited green acridine orange fluorescence. The percentage of normal sperm morphology, percentage of progressive motility, and percentage of green-fluorescing sperm were significantly better after this sperm preparation. Therefore, this sperm preparation technique is a convenient and efficient method to select progressive motile, normal morphological and normal nuclear DNA sperm for assisted conceptive technology.

La biología molecular en psiquiatría / Molecular biology in psychiatry

En el presente trbajo realizamos una revisión de las principales aportaciones, tanto nacionales como extranjeras, de la biología molecular a la psiquiatría. Se describen algunos conceptos fundamentales con el objeto de permitir al lector un entendimiento claro de las aportaciones actuales, y sentar las bases teóricas para el seguimiento de la literatura en el campo. Hasta ahora los hallazgos principales se han dado en las siguientes patologías: trastornos afectivos, esquizofrenia, alcoholismo, ansiedad y psicofarmacología. Finalmente, se describen algunas de las principales innovaciones metodológicas que se están llevando a cabo, y que seguramente se traducirán en la generación de un mayor nivel de conocimiento en cuanto a los mecanismos moleculares etiológicos en la patología mental

The effect of short-wavelength ultraviolet light on antigens, lection receptors and the ultraestructure of Crithidia fasciculata

Crithidia fasciculata is an important trypanosomatid parasite commonly affecting insects and is used extensively as a model for the study of the biochemistry, ultrastructure and organization of the kDNA network of trypanosomatids. The present study describes the evolution of UV-induced morphological changes detectable by transmission electron microscopy in Crithidia fasciculata. Although only rare and minor changes in Kinetoplast DNA were demonstrable 7 h after UV irradiation, alterations of this orgtanelle were present in almost al flagellates observed 24 h and 48 h after irradiation. Other cell structures were apparently undamaged. Ultrastructural changes in kDNA did not correspond to changes in antigenicity of protein bands in western blotting against serum from Chagas' disease patients or in the presence of 3 different lectin receptors on the surface of the parasite