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Distribution of extracellular signal-regulated kinase 1- and 2-activated neurons in the rat periaqueductal gray matter after noxious stimulation
No full textThe periaqueductal gray matter (PAG), the midbrain region made up of neuronal columns encircling the cerebral aqueduct, plays a key role in nociception. As the extracellular signal-regulated kinases (ERKs) 1 and 2 are activated after noxious stimulation, we analyzed the distribution of ERK-activated neurons in the PAG after visceral noxious stimulation. Ether- and urethane-anesthetized rats received an intraperitoneal injection of acetic acid or were left untreated and were perfused after 2 hr. Serial sections immunoreacted with an antibody selective for the activated ERKs. Significant ERK activation occurred only in the ether-anesthetized noxious stimulated rats. In these rats, we evaluated the number of ERK-activated neurons and their density as the ratio of the number of immunolabeled neurons to the extension of the region where they were located. ERK-activated neurons were more numerous in the lateral (LPAG) and ventrolateral (VLPAG) columns, but without significant differences. No ERK activation was seen in neurons of the most rostral PAG. The ERK-activated neurons were significantly denser at the intermediate level of the PAG. At the caudal level, they were denser in the LPAG and VLPAG columns, and in the DPAG column at the intermediate and rostral level. These findings suggest that noxious stimulation activates ERKs in neurons involved in the different functional activities related to nociception, overlapping in the PAG columns, and strengthens the role of PAG in integration
Immunocytochemical localization of extracellular signal-regulated kinases 1 and 2 phosphorylated neurons in the brainstem of rat following visceral noxious stimulation
No full textThe aim of the present study was to determine the activation of the extracellular signal-regulated kinases (ERKs) 1 and 2 in brainstem neurons following noxious visceral stimulation. Ether and urethane anaesthetized rats received an intraperitoneal injection of acetic acid (ENS, UNS) or were left untreated (ECT, UCT). Paraffin embedded brain sections immunoreacted with an antibody specific for phosphorylated ERKs. In noxious stimulated rats ERKs activated neuron profiles in the periaqueductal gray matter, parabrachial, dorsal raphe, solitary tract nucleus, area postrema and superior colliculus suggest that ERKs activation takes place mainly in brainstem nuclei in which nociception and visceral activities interact. The comparison between ENS and UNS rats shows that the long acting anaesthetic urethane attenuates the number of the ERKs activated neurons compared to the short acting ether
Analysis of the extracellular signal–regulated kinase 1 and 2 activated neurons distribution in the rat periaqueductal gray matter after noxious stimulation: an immunohistochemical study
No full textA morphometric model to minimize subjectivity in the histological assessment of hepatocellular carcinoma and its precursors in cirrhosis
No full textObjective: To explore how morphometry can minimize subjectivity in the assessment of liver nodules in cirrhosis using a novel classification tool. Study design: Ten hepatocellular carcinoma (HCC), 6 large regenerative nodules (LRN), and 34 regenerative (cirrhotic) nodules (RN), obtained from cirrhotic explant livers, were analyzed using a Kontron-Zeiss KS400 image analyzer. We generated a morphometric model based on the analysis of volume fractions occupied by hepatocyte nuclei/cytoplasm, sinusoidal endothelium and lumen, neoplastic acini, fibrosis, centrilobular veins, portal arteries, veins and bile ducts, individual lesional arteries (smooth muscle actin), and capillarized sinusoids (CD34), and on surface fraction occupied by reticulin, and number in unit volume and size distribution of hepatocyte nuclei, and mean hepatocyte nucleus diameter and volume. Results: Volume fraction of capillarized sinusoids and of individual lesional arteries were more prominent in HCC and LRNs, when compared with RN, whereas surface fraction of reticulin was markedly decreased in HCC. The morphometric values of these three features were integrated into our classification tool to construct a hybrid system, which reclassified the nodules in the same categories. Conclusion: Our novel hybrid classification tool may minimize subjectivity in the histological assessment of nodular lesions in cirrhosis
Friction and morphology of pleural mesothelia
Full text linkTo verify the hypothesis that by enmeshing lubricants, microvilli reduce the coefficient of kinetic friction (μ) of pleural mesothelium, μ was measured during reciprocating sliding of rabbit's visceral against parietal pleura before and after addition of hyaluronan, and related to the morphological features of the microvillar network. Because no relation was found between μ or μ changes after hyaluronan and microvillar characteristics, the latter are not determinants of the frictional forces which oppose sliding of normal mesothelial surfaces under physiological conditions, nor of the effects of hyaluronan. Addition of hyaluronan increased μ slightly but significantly in normal specimens, probably by altering the physiological mix of lubricants, but decreased μ of damaged mesothelia, suggesting protective, anti-abrasion properties. Indeed, while sliding of an injured against a normal pleura heavily damaged the latter and increased μ when Ringer was interposed between the surfaces, both effects were limited or prevented when hyaluronan was interposed between the injured and normal pleura before onset of sliding
Extracellular signal-regulated kinases 1 and 2 phosphorylated neurons in the tele- and diencephalon of rat after visceral pain stimulation: an immunocytochemical study.
No full textWe aimed at verifying whether extracellular signal-regulated kinases (erks) 1 and 2 are activated, i.e. phosphorylated,in forebrain neurons after visceral pain stimulation (VPS). Ether and urethane anaesthetized rats received an intraperitoneal injection of acetic acid or were left untreated (ECT, UCT). After 2 h the animals were perfused. Parafin embedded brain sections immunoreacted with an antibody selective for the phosphorylated erks. The light microscope analysis revealed only a few labelled neurons in ECT, while in UCT, positive cells were detected. In VPS rats (VPSR) positive cells were mainly distributed in regions, such as the hypothalamic anterior and thalamic paraventricular midline nuclei, amygdala, hippocampal and parahippocampal, insular and perirhinal cortex, involved in nociception and/or visceral activities. Our data suggest an association of erks activation with the emotional component of nociception; moreover, they show that erks activation is not suppressed by anaesthesia
Human visceral fat in different anthropometric patterns and in diabetes : a morphometric study
No full textObjective: To evaluate the cellularity of the adipose tissue and the size of adipocytes in unrelated adults and investigate any correlation between morphometric and anthropometric or clinical variables.
Study Design: Surgical biopsies of visceral fat (epiploic appendixes) were obtained from the large intestines of 56 patients. A morphometric model was applied to obtain the volume fraction occupied by adipocytes and the size distribution and number in unit volume of the adipocytes. Body mass index (BMI), lifestyle factors, significant body weight variations and clinical disorders (diabetes) were evaluated.
Results: Volume fraction occupied by adipocytes and size distribution and number in unit volume of the adipocytes have an opposite trend in underweight, normal and overweight subjects and subjects with referred gain, normal, or loss weight. Regression analysis reveals a significant negative linear relationship between number in unit volume of the adipocytes and BMI and body weight variations. The group of normal patients is characterized by a unimodal size distribution of adipocytes when compared with the group affected by diabetes, who show a likely plurimodal pattern.
Conclusion: Our observations seem to confirm the hypothesis that hypertrophy, rather than adipose tissue hyperplasia, plays a fundamental role when significant ponderal variations occur in adult life
Friction and lubrication of pleural tissues
No full textThe frictional behaviour of rabbit’s visceral pleura sliding against parietal pleura was assessed in vitro while oscillating at physiological velocities and amplitudes under physiological normal forces. For sliding velocities up to 3 cm s−1 and normal compressive loads up to 12 cm H2O, the average value of the coefficient of kinetic friction (μ) was constant at 0.019±0.002 (S.E.) with pleural liquid as lubricant. With Ringer-bicarbonate solution, μ was still constant, but significantly increased (Δμ=0.008±0.001; P < 0.001). Under these conditions, no damage of the sliding pleural surfaces was found on light and electron microscopy. Additional measurements, performed also on peritoneum, showed that changes in nominal contact area or strain of the mesothelia, temperature in the range 19–39 °C, and prolonged sliding did not affect μ. Gentle application of filter paper increased μ 10-fold and irreversibly, suggesting alteration of the mesothelia. With packed the red blood cells (RBC) between the sliding mesothelia, μ increased appreciably but reversibly on removal of RBC suspension, whilst no ruptures of RBC occurred. In conclusion, the results indicate a low value of sliding friction in pleural tissues, partly related to the characteristics of the pleural liquid, and show that friction is independent of velocity, normal load, and nominal contact area, consistent with boundary lubrication
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