Schiefer counter: An alternative method for clonogenic assay evaluation.

INTRODUCTION: Clonogenic assay evaluates the potential of cells to undergo division or generate clones following treatment with a chemical or other agent, thereby allowing the evaluation of cytotoxic and/or antiproliferative effects. Clonogenic assay analysis using traditional methods tends to be time-consuming and yield inconsistent results, whereas results from analyses conducted using automated image processing methods may be misleading or subject to misinterpretation. Thus, the aim of this work was to validate and demonstrate the applicability of a recently developed software. METHODS: Repeatability of measurements was evaluated by comparing results from 10 replicate images from a single well. To evaluate the viability of the software, results were compared with those obtained from manual counting, crystal violet optical density, and up-to-date automated methods. A clonogenic index was experimentally developed using the individual area occupied by colonies, while clone stratification was used to differentiate between antiproliferative and cytotoxic effects. RESULTS: The developed software showed to be a reliable and consistent tool for clonogenic assay evaluation, presenting a repeatability mean error of 0.79% for the number of colonies and 0.89% for the total area of colonies, as well as exhibiting a significant correlation (p < 0.05) with results obtained from widely adopted gold standard methods. The software was also able to detect an appropriate dose-dependent effect as well as a predominant cytotoxic effect of vincristine on MCF-7 cells and calculate the clonogenic index. DISCUSSION: Therefore, this software is adequate for the analysis of clonogenic assay images, differentiating between cytotoxic and antiproliferative trends.

Morphological aspects of the capybara stomach (Hydrochaeris hydrochaeris): gross and microscopic structure.

The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.

The gallbladder of the Capivara Hydrochoerus hydrochoeris (Mammalia: Rodentia).

The authors studied morphological and histochemically the mucopolysaccharides and proteins in the gallbladder tubular glands and epithelial cells of the capivara Hydrochoerus hydrochoeris. Based on the results the authors concluded: 1. the gallbladder single columnar epithelium consists of secretory, migrating, and goblet cells; 2. in the lamina propria are single coiled tubular glands; 3. goblet and tubular gland cells show neutral and sulphated mucopolysaccharides and sialic acid; 4. columnar cells show neutral mucopolysaccharides and protein radicals; 5. migrating cells show only protein radicals.