RESUMO
SUMMARY: Fixation is a crucial step in processing of tissue specimen for preservation of cellular architecture and composition of cells. Alcohol-based fixatives are considered some of the most promising alternatives to formalin. We evaluated the performance of alcohol-based fixatives (EthMeth and methacarn) and formalin as a comparator fixative in the research laboratory. Following 24 hours of fixation, tissue morphology and cellular details of the liver, spleen and brain (cerebral cortex) were evaluated. Morphological characteristics were evaluated by gross observations and analyzing cellular details, tissue architecture and overall staining characteristics (Hematoxylin and Eosin). EthMeth and methacarn fixation gave generally comparable and satisfactory results on the tissue morphology and subsequent identification of tissue characteristics. Particularly, tissues were well preserved and all nuclear as well as cytoplasmic details were clearly visible. However, formalin fixed tissues showed some peculiarity such as improper fixation, mild shrinkage, and alterations of tissue components. These results confirm that alcohol-based fixation is the superior alternative to formalin for preservation of tissue morphology. However, it is required to standardize the formalin-free methods and harmonize diagnosis in the laboratory worldwide.
RESUMEN: La fijación es un paso crucial en el procesamiento de muestras de tejido para preservar la arquitectura celular y la composición de las células. Los fijadores a base de alcohol se consideran algunas de las alternativas más prometedoras a la formalina. Evaluamos el rendimiento de los fijadores a base de alcohol (EthMeth y metacarn) y formalina como fijador comparativo en el laboratorio de investigación. Después de 24 horas de fijación, se observó la morfología del tejido y los detalles celulares del hígado, bazo y corteza cerebral. Se evaluaron las características morfológicas mediante observaciones generales y analizando detalles celulares, arquitectura de tejidos y características generales de tinción (hematoxilina y eosina). La fijación de EthMeth y metacarn dio resultados generalmente comparables y satisfactorios en la morfología del tejido y la posterior identificación de las características del mismo. Particularmente, los tejidos estaban bien conservados y todos los detalles nucleares y citoplasmáticos eran claramente visibles. Sin embargo, los tejidos fijados con formalina mostraron cierta peculiaridad, tal como una fijación inadecuada, la contracción leve y alteraciones de los componentes del tejido. Estos resultados confirman que la fijación a base de alcohol es la mejor alternativa a la formalina, para preservar la morfología del tejido. Sin embargo, es necesario estandarizar los métodos sin formalina y armonizar el diagnóstico en los laboratorios.
Assuntos
Fixação de Tecidos/métodos , Álcoois/química , Fixadores , Formaldeído/química , Clorofórmio/química , Ácido Acético/química , Metanol/químicaRESUMO
PURPOSE: Although there is limited evidence regarding the pathophysiological effects of a high-protein diet (HD), it is believed that this type of diet could overload the body and cause damage to the organs directly involved with protein metabolism and excretion. The aim of this study was to verify the effects of HD on biochemical and morphological parameters of rats that completed a resistance training protocol (RT; aquatic jump) for 8 weeks. METHODS: Thirty-two adult male Wistar rats were divided into four groups (n = 8 for each group): sedentary normal protein diet (SN-14%), sedentary high-protein diet (SH-35%), trained normal protein diet (TN-14%), and trained high-protein diet (TH-35%). Biochemical, tissue, and morphological measurements were made. RESULTS: Kidney (1.91 ± 0.34) and liver weights (12.88 ± 1.42) were higher in the SH. Soleus muscle weight was higher in the SH (0.22 ± 0.03) when compared to all groups. Blood glucose (123.2 ± 1.8), triglycerides (128.5 ± 44.0), and HDL cholesterol levels (65.7 ± 20.9) were also higher in the SH compared with the other experimental groups. Exercise reduced urea levels in the trained groups TN and TH (31.0 ± 4.1 and 36.8 ± 6.6), respectively. Creatinine levels were lower in TH and SH groups (0.68 ± 0.12; 0.54 ± 0.19), respectively. HD negatively altered renal morphology in SH, but when associated with RT, the apparent damage was partially reversed. In addition, the aquatic jump protocol reversed the damage to the gastrocnemius muscle caused by the HD. CONCLUSIONS: A high-protein diet promoted negative metabolic and morphological changes, while RT was effective in reversing these deleterious effects.