Cellular and extracellular markers of hemangioma

Several cellular and extracellular markers that distinguish the phases of the hemangioma life cycle have been described previously. However, details of the phenotypic changes of; the various cellular elements during hemangioma development have not been fully reported, and the extracellular matrix composition, especially in the vicinity of the proliferating endothelial cells, is poorly described. This study examined the expression of cellular and extracellular molecules and cytokines in the proliferative, involuting, and involuted phases of hemangioma. Paraffin-embedded hemangioma specimens, four from each phase, were examined histochemically and immunohistochemically. Throughout the three phases, vascular endothelial cells stained positive for CD31 and von Willebrand factor, although in the involuted phase, not all vessels in the tissue expressed these endothelial markers. Proliferating cell nuclear antigen was expressed by the majority of endothelial cells and pericytes in the proliferative and early involuting phases, but its expression was negligible in the involuted phase. In addition to finding that the total number of mast cells was highest in the involuting phase, the authors observed that the proportion of chymase-positive mast cells decreased with the progression of hemangioma and that virtually all mast cells expressed the biogenic amine phenotype throughout the hemangioma life cycle. The localization of vascular endothelial growth factor predominantly to the pericytes and endothelial cells during the proliferative phase and of basic fibroblast growth factor to the endothelial cells in both the proliferative and early involuting phases is consistent with previous reports, although the latter growth factorwas also observed in mast cells. Type IV collagen and the beta chain of laminin and perlecan were detected in the basement membranes in all phases. Interestingly, collagen types I, III, and V were present in basal membranes throughout the phases and with increasing density in the stromal areas with involution, although type I collagen was less prominent during the proliferative phase. Short-chain collagen type VIII was localized extracellularly throughout the development of hemangioma but, during the early proliferative phase, it was also detected within mast cells. The expression of specific cytokines and cellular and extracellular markers may help distinguish the different clinical phases of the hemangioima life cycle. These results provide further insight into the biology of hemangioma.     

The effect of acute heat exposure on rat pituitary corticotroph activation: the role of vasopressin

The increased ambient temperature affects the function of hypothalamic-pituitary-adrenal (HPA) axis. Since the correlation among vasopressin (VP), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses to various stressors have been long recognized, the aim of this study was to reveal the aforementioned hormones production and morphology of the pituitary gland after exposure to acute heat. Rats were exposed to high ambient temperature (38 °C) for 20 or 60 minutes. The circulating hormones were determined by an ELISA test or chemiluminescence's method. The results obtained show the elevation in ACTH and CORT secretion depending on the duration of heat exposure. The VP concentration increased only after prolonged exposure to heat (60 min). The pituitary morphology was examined by routine and fluorescent immunohistochemistry as well as electron microscopy. Observed changes in the anterior and posterior pituitary well corresponded to circulating hormones, regarding the volume density of ACTH-immunopositive cells, percentage of ACTH immunopositive area v. total area and number of VP-immunopositive containing varicose fibers per total area. Acute heat exposure also induced changes in shapes of ACTH-immunopositive cells. Cells appeared stellate with numerous slender cytoplasmic processes and degranulated, which is the most obvious after 20 min. In addition, immunopositivity of endothelial and anterior pituitary cells for VP suggests its influence on ACTH secretion.     

A modified version of fluctuating asymmetry, potential for the analysis of Aesculus hippocastanum L. compound leaves

My research interest was to create a new, simple and tractable mathematical framework for analyzing fluctuating asymmetry (FA) in Aesculus hippocastanum L. palmately compound leaves (each compound leaf with 7 obviate, serrate leaflets). FA, being random differences in the development of both sides of a bilaterally symmetrical character, has been proposed as an indicator of environmental and genetic stress. In the present paper the well-established Palmer's procedure for FA has been modified to improve the suitability of the chosen index (FA1) to be used in compound leaf asymmetry analysis. The processing steps are described in detail, allowing us to apply these modifications for the other Palmer's indices of FA as well as for the compound leaves of other plant species.     

Endothelial cell apoptosis in brown adipose tissue of rats induced by hyperinsulinaemia: the possible role of TNF-α

The aim of the present study was to investigate whether hyperinsulinaemia, which frequently precedes insulin resistance syndrome (obesity, diabetes), induces apoptosis of endothelial cells (ECs) in brown adipose tissue (BAT) and causes BAT atrophy and also, to investigate the possible mechanisms underlying ECs death. In order to induce hyperinsulinaemia, adult male rats of Wistar strain were treated with high dose of insulin (4 U/kg, intraperitonealy) for one or three days. Examinations at ultrastructural level showed apoptotic changes of ECs, allowing us to point out that changes mainly but not exclusively, occur in nuclei. Besides different stages of condensation and alterations of the chromatin, nuclear fragmentation was also observed. Higher number of ECs apoptotic nuclei in the BAT of hyperinsulinaemic rats was also confirmed by propidium iodide staining. Immunohistochemical localization of tumor necrosis factor-alpha (TNF-α) revealed increased expression in ECs of BAT of hyperinsulinaemic animals, indicating its possible role in insulin-induced apoptotic changes. These results suggest that BAT atrophy in hyperinsulinaemia is a result of endothelial and adipocyte apoptosis combined, rather than any of functional components alone.     

Effect of acute heat stress on rat adrenal cortex — a morphological and ultrastructural study

The stereological structure of rat adrenal gland was analysed by light and electron microscopy after an acute (60 min) exposure to high ambient temperature (38°C). Under these conditions a significant increase in plasma corticotrophin (ACTH), serum corticosterone and aldosterone levels were observed. Histological and stereological investigation at light microscopy showed significant decrease in volume density of capsule and zona glomerulosa, increase in volume of fasciculata cells, and decrease of numerical density of zona fasciculata cells and mean diameter of blood vessels. At the ultrastructural level, volume density of nuclei and mitochondria of zona glomerulosa cells were significantly increased and that of lipid droplets decreased. Volume density of mitochondria of fasciculata cells was significantly increased, while number of lipid droplets per μm² of cell was reduced. In the cells of zona reticularis significant increase in the number of lipid droplets was found. The response of zona glomerulosa may be interpreted as immediate reaction to dehydration, while alterations detected in zona fasciculata, which were less extensive, were related to purely stressogenic effects of high ambiental temperature.     

Calcium-Induced Alteration of Mitochondrial Morphology and Mitochondrial-Endoplasmic Reticulum Contacts in Rat Brown Adipocytes

Mitochondria are key organelles maintaining cellular bioenergetics and integrity, and their regulation of [Ca²⁺]_i homeostasis has been investigated in many cell types. We investigated the short-term Ca-SANDOZ^® treatment on brown adipocyte mitochondria, using imaging and molecular biology techniques. Two-month-old male Wistar rats were divided into two groups: Ca-SANDOZ^® drinking or tap water (control) drinking for three days. Alizarin Red S staining showed increased Ca²⁺ level in the brown adipocytes of treated rats, and potassium pyroantimonate staining localized electron-dense regions in the cytoplasm, mitochondria and around lipid droplets. Ca-SANDOZ^® decreased mitochondrial number, but increased their size and mitochondrial cristae volume. Transmission electron microscopy revealed numerous enlarged and fusioned-like mitochondria in the Ca-SANDOZ^® treated group compared to the control, and megamitochondria in some brown adipocytes. The Ca²⁺ diet affected mitochondrial fusion as mitofusin 1 (MFN1) and mitofusin 2 (MFN2) were increased, and mitochondrial fission as dynamin related protein 1 (DRP1) was decreased. Confocal microscopy showed a higher colocalization rate between functional mitochondria and endoplasmic reticulum (ER). The level of uncoupling protein-1 (UCP1) was elevated, which was confirmed by immunohistochemistry and Western blot analysis. These results suggest that Ca-SANDOZ^® stimulates mitochondrial fusion, increases mitochondrial-ER contacts and the thermogenic capacity of brown adipocytes.Key words: Brown adipocyte, mitochondrial dynamics, calcium, endoplasmic reticulum     

Leaf fluctuating asymmetry of common plantain as an indicator of habitat quality

Abstract

Although developmental instability (DI), measured as fluctuating asymmetry (FA), is expected to be positively related to environmental stress and negatively to habitat quality, the pattern found here was the reverse. Developmental instability of leaf traits (leaf width and vein distances within a leaf) was estimated (using two indices of FA: FA₄ and σ_i ²) and compared between three populations of Plantago major L. (Plantaginaceae) from northern Serbia. Two of the populations are from chronically polluted areas (Karaburma & Zemun), while Crni Lug is from an unpolluted, natural area. Results obtained using both FA indices were the same; higher asymmetry levels in the unpolluted area than in the polluted sites, were found for both traits. Between the two polluted sites, FA values were significantly higher in Karaburma site for vein distances within a leaf. Concerning differences in FA₄ values between samples, in two cases, results are similar to those found for σ_i ² values, for vein distances within leaf. These are the first quantitative data on P. major indicating that (i) plants living in the stressful sites are more symmetrical and (ii) leaf FA for plant species with wide ecological distribution such as P. major should be considered as an ‘index of habitat quality.’