Quantitative morphology update: image analysis / Actualización de morfología cuantitativa: análisis de imagen

Quantitative morphology is a reliable tool in developmental, clinical and aging biology. Quantitative data of histological improvement and/or impairment due to dietary manipulations or pharmacological interventions draws the attention of countless researchers worldwide. Morphometry allows a wide range of two-dimension analysis to be performed, whereas image segmentation allows the measurement of a single structure or the determination of the intensity of its color after adequate immunostaining or even the area occupied by a specific sort of cell. When it comes to unbiased analysis, consideration should be given to suitable tissue perfusion, fixation and embedding, avoiding artifacts. Furthermore, tissue shrinkage should be taken into account. In order to ensure reproducibility, one of the most important principles in scientific research, and to allow different groups to be compared, image acquisition and image segmentation emerge as crucial steps and should be standardized. This paper aims to approach some important care for appropriate tissue processing and evaluation, and shows some practical examples of how morphometry and image segmentation can be applied to your experiment.

La morfología cuantitativa es una herramienta confiable en la biología del desarrollo, clínica y en el envejecimiento. Los innumerables datos cuantitativos de mejoras histológica y / o deterioro debido a las manipulaciones dietéticas o intervenciones farmacológicas atraen la atención de los investigadores en todo el mundo. La morfometría permite realizar una amplia gama de análisis en dos dimensiones, mientras que la segmentación de imágenes permite la medición de una única estructura o la determinación de la intensidad de su color después de una adecuada inmunotinción o incluso el área ocupada por un tipo específico de célula. Cuando se trata de un análisis imparcial, debe considerarse la posibilidad de la perfusión tisular adecuada, fijación e inclusión, evitando artefactos. Además, se debe considerar la contracción del tejido. Con el fin de asegurar la reproducibilidad, uno de los principios más importantes en la investigación científica, y para permitir que diferentes grupos se comparen, la adquisición y segmentación de la imagen aparecen como pasos cruciales y deben ser estandarizados. En este trabajo se abordan algunos cuidados importantes para el procesamiento de tejidos y evaluación apropiadas, y se muestran algunos ejemplos prácticos de cómo la segmentación morfométrica y la imagen se pueden aplicar a su experimento.

Histologic Changes of Pulmonary Arteries in Congenital Heart Disease with Left-to-Right Shunt (Part 1): Correlated with Preoperative Pulmonary Hemodynamics. Emphasizing the Significance of Pulmonary Arterial Concentration

The hemodynamic findings related to the histologic changes in the small pulmonary arteries in congenital heart disease were analyzed with a left-to-right shunt. A lung biopsy was performed during the repair because of pulmonary arterial (PA) hypertension (mean PA pressure > or = 15 mmHg) in 38 patients. There were 13 patients whose age ranged from 2 years to 25 years old. A preoperative cardiac catheterization was performed to locate the site of the defect and to determine the preoperative hemodynamic findings. Among them, 29 patients had pulmonary vascular resistance (PVR) > 2.5 unit/m2. The lung biopsy specimens were investigated microscopically for the Heath- Edward grade, morphometric analysis of medial wall thickness (MWT) and the rate of the decrease in the pulmonary arteriolar concentration (PAC) obtained by the alvoelo-arterial ratio divided by patients' age. All patients were in the Heath-Edward grade I to III (29 patients in grade I). This grade correlated with the MWT, but did not correlate with a decrease in the PAC. The MWT and the rate of the decrease in the PAC did not accompany each other, but either one had the tendency dominate the pattern in individual patients. The MWT had a close correlation with the mean PA pressure and PVR, and an even closer correlation in patients with a high PVR and those older than 2 years of age. The rate of the decreased in the PAC showed a weak correlation with the shunt volume in patients over 2 years of age or with a large shunt. In the high flow group (PVR 2.0, n=14) the MWT was significantly thinner and the rate of the decrease in the PAC was significantly higher than the high resistance group (PVR > 2.5 unit/m2, Qp/Qs2 < 2.0, n=13). The rate of the decrease in the PAC correlated with the patients' age, but the MWT did not. The lung biopsy results in patients who had both left-to-right shunts and pulmonary hypertension showed that the rate of the decrease in the PAC was weakly related to the shunt volume and the MWT was related to the PA pressure and PVR. Either an increased MWT or the rate of the decrease in the PAC tended to dominate. These phenomena were prominent in patients older than 2 in whom a wide range of individual variations were noted in the morphometric pattern. The medial hypertrophy and the rate of the decrease in the PAC may be induced by different stimuli or that medial hypertrophy may play a role in preventing PAC decrease.

Histologic Changes of Pulmonary Arteries in Congenital Heart Disease with Left-to-Right Shunt (Part 2): Emphasis on the Significance of Pulmonary Arterial Concentration in the Correlation with Pulmonary Hemodynamics after Repair Ed- The Above is An Altern

We performed this study to assess the correlation of residual pulmonary hypertension in the immediate postoperative period with that in the late follow-up period, to assess the histologic changes of pulmonary arteries (PA) at the time of repair for patients with congenital heart disease consisting of left-to-right shunt, and to clarify the role of lung biopsy in determining the operability and reversibility of pulmonary vascular changes. Lung biopsy was performed during repair in 38 patients, with a wide range of age, who had congenital left to right shunt and pulmonary hypertension. All were Heath-Edward grade III or less. Morphometric study included measurement of medial wall thickness (MWT) and decrease rate of pulmonary arterial concentration (PAC). Mean PA pressure in the immediate postoperative period was measured in all 38 patients. Follow-up cardiac catheterization was performed in 15 patients (average 3.8 years after repair). At operation, 5 patients of this late follow-up group were under 2 years of age and the other 10 were 2 or more. During catheterization, pulmonary hemodynamic reaction was observed both under room air inhalation and after inhalation of hypoxic gas FiO2 0.15. Mean PA pressure and pulmonary vascular resistance (PVR) in the immediate postoperative period had a significant correlation with PA pressure and PVR values before the operation, but not with morphometry, Heath-Edward grade, or with pulmonary hemodynamics in late follow-up. During the late follow-up study, 5 of the 15 patients had pulmonary hypertension (defined as mean PA pressure > or = 15 mmHg) under room air inhalation, and PA hypertension was induced in 4 additional patients after hypoxic gas inhalation. There was no incidence of PA pressure or PVR values registering above the preoperative level. The degree of PA hypertension showed a correlation with the rate of PAC decrease and also with patients' age-at-operation. Multiple regression analysis showed that both the rate of PAC decrease and the age-at-operation contributed significantly to the degree of PA hypertension. Some of the patients over age 2 had a decreased rate of PAC above the regression line, which none of the patients under age 2 experienced. In patients with Heath-Edward grade III or less, residual pulmonary hypertension in the immediate postoperative period was not correlated with histology, but in late follow-up, it was with PAC and the age-at-operation. Therefore, a decrease of PAC is assumed to be a totally or partially irreversible pulmonary vascular change depending on the patient's age-at-operation, while medial hypertrophy is thought to be a reversible pulmonary vascular change. Lung biopsy could play an important role in determining the reversibility of pulmonary vascular obstruction, particularly in patients older than 2 years. Ed- re highlights above: such hyphenation is optional, but if used then it should be applied consistently throughout the paper. As 3 of the 4 entries in the abstract use it, I have maintained it consistently below.