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Reactive oxygen species (ROS) are currently recognized as a key driver of several physiological processes. Increasing evidence indicates that ROS levels can affect myogenic differentiation, but the molecular mechanisms still need to be elucidated. Protein kinase C (PKC) epsilon (PKCe) promotes muscle stem cell differentiation and regeneration of skeletal muscle after injury. PKCs play a tissue-specific role in redox biology, with specific isoforms being both a target of ROS and an up-stream regulator of ROS production. Therefore, we hypothesized that PKCe represents a molecular link between redox homeostasis and myogenic differentiation. We used an in vitro model of a mouse myoblast cell line (C2C12) to study the PKC-redox axis. We demonstrated that the transition from a myoblast to myotube is typified by increased PKCe protein content and decreased ROS. Intriguingly, the expression of the antioxidant enzyme superoxide dismutase 2 (SOD2) is significantly higher in the late phases of myogenic differentiation, mimicking PKCe protein content. Furthermore, we demonstrated that PKCe inhibition increases ROS and reduces SOD2 protein content while SOD2 silencing did not affect PKCe protein content, suggesting that the kinase could be an up-stream regulator of SOD2. To support this hypothesis, we found that in C2C12 cells, PKCe interacts with Nrf2, whose activation induces SOD2 transcription. Overall, our results indicate that PKCe is capable of activating the antioxidant signaling preventing ROS accumulation in a myotube, eventually promoting myogenic differentiation.

In cancer metastasis, intravasation of the invasive tumor cell (TCi) represents one of the most relevant events. During the last years, models regarding cancer cell intravasation have been proposed, such as the "endocanalicular transendothelial crossing" (ETC) theory. This theory describes the interplay between two adjacent endothelial cells and the TCi or a leukocyte during intravasation. Two endothelial cells create a channel with their cell membranes, in which the cell fits in without involving endothelial cell intercellular junctions, reaching the lumen through a transendothelial passage. In the present study, ten SCID mice were subcutaneously xenotransplanted with the HEK-EBNA293-VEGF-D cell line and euthanized after 35 days. Post-mortem examinations were performed and proper specimens from tumors were collected. Routine histology and immunohistochemistry for Ki-67, pAKT, pERK, ZEB-1, TWIST-1, F-actin, E-cadherin and LYVE-1 were performed followed by ultrastructural serial sections analysis. A novel experimental approach involving Computed Tomography (CT) combined with 3D digital model reconstruction was employed. The analysis of activated transcription factors supports that tumor cells at the periphery potentially underwent an epithelial-to-mesenchymal transition (EMT)-like process. Topographical analysis of LYVE-1 immunolabeled lymphatics revealed a peritumoral localisation. TEM investigations of the lymphatic vessels combined with 3D digital modelling enhanced the understanding of the endotheliocytes behavior during TCi intravasation, clarifying the ETC theory. Serial ultrastructural analysis performed within tumor periphery revealed numerous cells during the ETC process. Furthermore, this study demonstrates that ETC is an intravasation mode more frequently used by the TCi than by leukocytes during intravasation in the HEK-EBNA293-VEGF-D xenograft model and lays down the potential basis for promising future studies regarding intravasation blocking therapy., Competing Interests: The authors have declared that no competing interests exist.

In the last 15 years, it emerged that the practice of regular physical activity reduces the risks of many diseases (cardiovascular diseases, diabetes, etc.) and it is fundamental in weight control and energy consuming to contrast obesity. Different groups proposed many molecular mechanisms as responsible for the positive effects of physical activity in healthy life. However, many points remain to be clarified. In this mini-review we reported the latest observations on the effects of physical exercise on healthy skeletal and cardiac muscle focusing on muscle stem cells. The last ones represent the fundamental elements for muscle regeneration post injury, but also for healthy muscle homeostasis. Interestingly, in both muscle tissues the morphological consequence of physical activity is a physiological hypertrophy that depends on different phenomena both in differentiated cells and stem cells. The signaling pathways for physical exercise effects present common elements in skeletal and cardiac muscle, like activation of specific transcription factors, proliferative pathways, and cytokines. More recently, post translational (miRNAs) or epigenetic (DNA methylation) modifications have been demonstrated. However, several points remain unresolved thus requiring new research on the effect of exercise on muscle stem cells., Competing Interests: Conflict of interests: No authors report any conflict of interest.

Rationale: Vessel formation is a crucial event in tissue repair after injury. Thus, one assumption of innovative therapeutic approaches is the understanding of its molecular mechanisms. Notwithstanding our knowledge of the role of Protein Kinase C epsilon (PKCε) in cardio-protection and vascular restenosis, its role in vessel progenitor differentiation remains elusive., Objective: Given the availability of PKCε pharmacological modulators already tested in clinical trials, the specific aim of this study is to unravel the role of PKCε in vessel progenitor differentiation, with implications in vascular pathology and vasculogenesis., Methods and Results: Mouse Peri-Vascular Adipose Tissue (PVAT) was used as source of mesenchymal vessel progenitors. VEGF-induced differentiation of PVAT cells down-regulates both PKCε and p-PAK1 protein expression levels. PKCε overexpression and activation: i) reduced the expression levels of SMA and PECAM in endothelial differentiation of PVAT cells; ii) completely abrogated tubules formation in collagen gel assays; iii) increased the expression of p-PAK1., Conclusion: PKCε negatively interferes with vessel progenitor differentiation via interaction with PAK-1., (Copyright © 2014 Elsevier Inc. All rights reserved.)

How the lymphocyte crosses the blood endothelium during transendothelial migration is demonstrated through the study of serial sections of high endothelial venules (HEVs) of peripheral (mesenteric lymph nodes) and mucosa-associated lymphoid tissue (Peyer's patches, vermiform appendix) during normal lymphocyte homing and experimental intestinal inflammation. The sequence of serial ultrastructural features of lymphocytes englobed in the endothelial wall at different moments of transmigration made it possible to bring out that their transendothelial migration toward the extracellular matrix of lymphoid tissues occurs through an intraendothelial canalicular formation constituted by two adjacent endothelial cells that have closed interendothelial junctions. This intraendothelial canalicular formation, morphologically unlike the transcellular and paracellular migratory pathways, is an innovative model of migratory route for lymphocyte diapedesis that does not compromise the continuity of the endothelial wall. The increased presence of lymphocytes and intraendothelial canalicular formations during experimental inflammation and the metabolic hyperactivity of the spring/summer months compared to the lethargic fast in Chiropters underscores an influence on lymphocyte traffic through the HEVs of the peripheral and mucosa-associated lymphoid tissue.

The mode of lymphocyte transendothelial migration in the postcapillary high endothelial venules (HEVs) of Peyer's patches during normal homing and acute inflammation in the guinea pig was studied. It is common opinion that the lymphocyte transendothelial passage from the blood stream into the extravasal lymphoid tissue calls for a multistep process of endothelial and lymphocyte molecules favoring tethering, rolling, activation, arrest and its firm adhesion to the endothelial luminal surface. Ultrastructural serial pictures and the three-dimensional reconstruction of HEVs with lymphocytes during different moments of their transmigration through the endothelial wall enabled us to demonstrate in vivo the morphological modality of their extravasation in lymphoid tissue. The latter is accomplished by means of an intraendothelial canalicular formation (6.8-7.2 microm long and 2.1-2.2 microm in diameter), whose creation depends on the particular behavior of adjacent endothelial cells, without compromising the interendothelial contacts. This new canalicular pathway of lymphocyte extravasation, particularly selective for the B cell, does not permit confirmation of the dogmas of the transcellular and paracellular (open interendothelial junctions) modes that have prevailed in recent decades. The lack of knowledge regarding the molecular bases that would induce constitution of this intraendothelial canalicular formation is a critical point for stimulating future interdisciplinary research aimed at developing strategies for modulating normal lymphocyte homing and in inflammation.

The present work aims at investigating the changes in motor responsiveness of rat intestine hypertrophied by chronic mechanical obstruction. Motor responses to pharmacological agents and electrical field stimulation (EFS) were studied in hypertrophic ileal segments excised from rats subjected to experimental stenosis (n = 20) and compared with responses of control tissues from sham-operated animals (n = 20). Spontaneous motility and contractile responses to exogenous agents (KCl, acetylcholine and substance P) and EFS (10-s trains every minute, 120 mA, 0.5 ms, 1-10 Hz) were increased in hypertrophic longitudinal segments; however, normalization of motor responses to tissue wet weight revealed a remarkable reduction of contractile efficiency in hypertrophied tissues coupled with a loss of sensitivity to nitric oxide-mediated relaxation. Furthermore, EFS under non-adrenergic non-cholinergic (NANC) conditions unveiled a major role of the cholinergic component over the peptidergic one in the neurogenic contraction of hypertrophic intestine. On the whole, hypertrophic intestinal growth emerges as a dynamic process entailing adaptation of smooth muscle and neuronal structures to the increased functional load imposed by lumen obstruction.

The topography and structure of the follicular cells and the follicular cavity of the hypophyseal pars tuberalis (PT) were studied in adult hibernating bats (Pipistrellus pipistrellus and Rhinolophus ferrumequinum) of both sexes, during the annual seasonal cycle and the reproductive cycle. The follicular cells were found to be organized around a central cavity. They showed a polyhedral shape and apical microvilli protruding into central cavities. During hibernation, the follicular cells showed active cytoplasmic organelles, clusters of glycogen particles, and lipid droplets. In the supranuclear cytoplasm, 9+2 type cilia, some dense bodies, microvesicular vacuoles, and thin actin-like filaments (rather scarce during autumn) were detected. The contents of the follicular cavity showed well-defined ultrastructural seasonal characteristics, with a colloid-like aspect during awakening and a strongly granular aspect during autumn oestrus and mating. Positive staining for PAS and paraldehyde fuchsin, and a marked reaction to lectins PHA-L4, MAM, and RCA 60 suggested the presence of sialo-glycoproteins in the follicular cavities. Both follicular and endocrine PT-specific cells appeared to mark the boundary of follicular cavities. This finding suggests that the follicular cavity contents are comprised of both types of cells, rather than by cell fragmentation or degeneration products., (Copyright 2003 Wiley-Liss, Inc.)

In Pars tuberalis (PT) of pituitary gland of hibernating bats, extending cranially along the ventral face of the hypothalamic median eminence, around the hypophyseal stalk, and caudally continuing in the Pars distalis (PD), pt specific cells, follicular cells and gonadotropic cells were distinguished. Pt specific cells contain peculiar secretory granules positive to lectin WGA and negative to lectins LFA and PNA, positive to S-100 protein labeling and to PD hormones antisera. During hibernation they present a low numerical density of both secretory granules and melatonin binding sites. After light exposure, on the other hand, the latter increase in density and are associated with marked secretion synthetic activity and exocytosis. These aspects result to be more balanced in animals sacrificed during summer. These changes seem to support the hypothesis of marked annual changes even in animal species with seasonal rhythmicity of metabolisms and gonads. Follicular cells, organized in closed follicles, have slightly developed RER and Golgi apparatus during hibernation, whereas they seem to show an increased secretory activity after light exposure and during summer. In perinuclear and supranuclear cytoplasm, glycogen particles clusters (peculiar of hibernation), cilia 9+2 and multivesicular bodies were identified. Concerning FSH cells, a reduced numerical density during hibernation, the secretory granules morphological characteristics and their probable involvement in photoperiod-linked reproductive functions are investigated.

Corrosion casts from neoprene direct injection of lymphatic and blood vessels in guinea pig gut-associated lymphoid tissue, that is, solitary lymphoid follicles and Peyer's patches, have shown both their numerical density and their topographical arrangement in physiological conditions, after starvation and lymphatic stasis. The absorbing peripheral lymphatic vessel (ALPA) begins with the lacteal vessel, which continues in the mucosal lymphatic network. The latter is formed by subepithelial and interfollicular vessels wrapping single lymphoid follicles like a basket. Interfollicular vessels drain in the submucosal network, which flows into muscular tunica vessels with nonsegmentary bicuspid valves. They in turn drain lymph in subserosal precollectors and then in prelymphonodal collectors with conduction function. The follicles' germinal center and dome are completely devoid of ALPA vessels, while they are rich in blood vessels. Ultrastructurally, the ALPA vessel wall consists of a monolayer of endothelial cells devoid of pores, fenestrations, and open junctions and lacking a continuous basal lamina. Endothelial cells are joined by overlapping and interdigitating intercellular contacts, while end-to-end contacts are rare. They have a sizeable cell body, containing the nucleus and the common endocytoplasmic organelles, and a peripheral cytoplasm with actin-like filament bundles, free microvesicles or forming channels and a few rough-surfaced encloplasmic reticulum (RER) canaliculi. The presence of intraendothelial channels crossed by lymphocytes can often be detected within the endothelial wall during the different phases of cell transendothelial migration from lymphoid tissue to lymphatic vessel lumen. These channels undergo a numerical increase during starvation, while they are scarce during lymphatic stasis. We have quantitatively evaluated the prevalence of T lymphocytes in the lymph of interfollicular ALPA vessels and of prelymphonodal collectors draining the small intestine tract with or without Peyer's patches, under physiological and experimental conditions (starvation, lymphatic stasis).

We studied the absorbing lymphatic peripheral vessels of the Peyer's patches of the small and large intestine of the rabbit by means of light microscopy after injection of Neoprene latex and transmission electron microscopy in order to highlight their topographical distributions to blood vessels as well as the morphologic mechanism of transendothelial passage of the lymphocytes to the lymph. The distribution of absorbing lymphatic vessels originates from the lacteal vessels and the subepithelial mucosal lymphatic network, which continue without interruptions and dilations into the vessels of the interfollicular area which are woven into basket-like networks entwining the medio-basal portion of each lymphoid follicle. The interfollicular area vessels then drain into the large vessels of the tunica submucosa, which in turn drain into the valved precollector vessels of the subserosa by way of intramuscular vessels. TEM revealed the absorbing lymphatic vessels to have a continuous endothelial wall without open junctions, fenestrations, and continuous basal lamina. We observed many lymphocytes wedged in the lymphatic endothelial wall. This underlines the different phases of their migration from the lymphoid tissue in the lumen of the lymphatic vessel. Results of ultrathin serial sections and three dimensional reconstruction of lymphatic vessel segments with included lymphocyte showed the transendothelial passage of lymphocyte, through the "intraendothelial channels.", (Copyright 2000 Wiley-Liss, Inc.)

(R)-alpha-Methylhistamine, a selective agonist of histamine H3 receptors, prevents macroscopically visible gastric lesions by absolute ethanol in the rat. A further insight into its activity was the aim of our study. Rats were given saline or (R)-alpha-methylhistamine (100 mg/kg) intragastrically. After 30 min, absolute ethanol was given and gastric mucosa was sampled 60 min later. Histologic damage and intracellular and adherent mucus were quantified. Luminal surface and mucous cells were examined by scanning and transmission electron microscopy. (R)-alpha-Methylhistamine reduced the extent of lesions by ethanol from 96 to 18%. Surface mucous cells and mucous neck cells were increased in volume and number, packaging of intracellular mucus was modified, and the secretory processes were promoted by (R)-alpha-methylhistamine itself, although these modifications were mostly evident in stomachs subsequently exposed to ethanol. Adherent mucus layer thickness was increased by (R)-alpha-methylhistamine only after ethanol exposure. It is concluded that (R)-alpha-methylhistamine predisposes mucous cells to react to ethanol.

The cells of vallate, foliate and fungiform papillae were studied in insectivore hibernating bats (Pipistrellus pipistrellus and Rhinolophus ferrumequinum) in the various epochs of the year in order to show cell types the seasonal changes. On the basis of the ultrastructural aspects and the relationships with nerve endings, besides the few basal cells, three types of sensorial cells can be identified: dark type I cells, light type II cells and light type III cells. All gustatory cells, long and narrow shaped, extend from the epithelial basal lamina to the gustatory canal, where they send long microvillous expansions of the apical cytoplasm. These expansions, except those of the fungiform papillae which never extend beyond the lower two thirds, usually reach the external opening of the taste pore, always completely void of dense substance. Dark type I cells are characterized by a developed RER and large granules. Light type III cells show peculiar dense core light vesicles, labelled protein A-gold particles immunoreactive to 5-HT. These cells only in the foliate and fungiform papillae also have bundles of microtubules whose function is still unknown. After comparative evaluation and discussion of topographical and ultrastructural aspects with those of other mammals and humans, the Authors states that bats are provided with a valid gustatory system and that all cell types are involved in taste transduction.

Background: The mechanisms responsible for the gastric ulcerogenic effect of indomethacin are unclear. The importance of basal acid secretion on morphological changes by indomethacin was investigated., Methods: Gastric lesions were macroscopically evaluated 6 h after indomethacin, 20 mg/kg intragastrically, in rats pre-treated with omeprazole (10-100 mumol/kg intragastrically) or lansoprazole (3-30 mumol/kg intragastrically). Glandular mucosa was processed for light, scanning and transmission electron microscopy 3 and 6 h after indomethacin in rats pre-treated with omeprazole (100 mumol/kg) or lansoprazole (30 mumol/kg)., Results: After 3 h, indomethacin caused extensive vasocongestion, oedema in the subepithelial region and superficial erosions. After 6 h, deeply extending focal necrosis involved 11% of the tissue. Leukocyte margination was occasionally seen at 3 h and consistently present at 6 h. Only at 6 h were endothelial cells altered. In rats pre-treated with omeprazole (100 mumol/kg) or lansoprazole (30 mumol/kg) grossly visible lesions were prevented. Oedema, erosions and necrosis were absent. Vasocongestion, vascular leakage and leukocytic margination were seen both at 3 and 6 h while no major damage of endothelial cells was observed., Conclusion: Indomethacin appears primarily to alter microcirculation, and microcirculation damage is dependent on acid for the progression to haemorrhagic lesions.

1. The protective activity of lansoprazole was evaluated on gastric mucosal lesions induced by intragastric 25% NaCl (1 ml/rat for 1 hr) and by indomethacin (20 mg/kg for 6 hr) in the rat and compared with that of omeprazole. 2. Lansoprazole (3, 10 and 10 mumol/kg i.g.) dose-dependently prevented the formation of indomethacin-induced lesions, the inhibition being 99% at the highest dose. Omeprazole, 10 mumol/kg i.g., enhanced the damage by indomethacin while higher doses caused a reduction, lesion index being reduced by 98% at 100 mumol/kg. 3. Histologically in lansoprazole- as well as in omeprazole-pretreated rats, indomethacin-induced necrosis of the mucosa was absent, luminal epithelium being intact. 4. Lansoprazole (30, 100 and 300 mumol/kg) and omeprazole (30, 100 and 300 mumol/kg) dose-dependently reduced the formation of lesions by hypertonic saline. 5. Present results indicated that lansoprazole and omeprazole protect the gastric mucosa in different experimental models of gastric ulceration.

The gallbladder of the insectivorous hibernating bats (Pipistrellus pipistrellus et Rhinolophus ferrumequinum) in fullness, shows a fundus, a corpus and a neck. Its wall is formed by three layers: mucous membrane, with simple columnar epithelium on a thin basal lamina, beneath which is a "lamina propria" of connective tissue with blood and lymphatic vessels; lamina muscularis, constituted by three of four parallel bundles of smooth muscle cells, arranged in circular pattern; serous membrane of loose connective tissue, with precollecting lymphatic vessels and covered by mesothelial cells. By SEM the luminal surface of mucous membrane shows more or less prominent folds delimiting irregular areas with hexa-pentagonal outlines of the apical region of epithelial cells. This latter present a convex dome aspect with numerous microvilli, not changed significantly, during the different year periods. In summer and autumn the epithelial cells are characterized by developed organelles in supranuclear cytoplasm. During the prehibernating period, chiefly the cytoplasm shows multivesicular and heterogeneous dense bodies. In summer, autumn and initial hibernating period, epithelial cell cytoplasm presents microvilli with prominent "antennulae microvilares", numerous light micropinocytosis vesicles, little rough vesicles in apical portion. The mitochondria, grouping in supranuclear and basal cytoplasm, in lethargy, are characterized by small matrix osmiophilic granules. The epithelial cells are held together near the apical surface by tight and gap junctions, and some rare desmosomes only in Rhinolophus f.e. The cell membranes are deep pleated or interdigitate with wide intercellular spaces during the prehibernating period and experimental arousing, while in lethargy and summer months these present linear outline with scanty invaginations. The Authors compared these morphological aspects of bat gallbladder with other micromammalia's one, underline particularly the functional role of dense bodies, wide intercellular spaces and apical micropinocytosis vesicles. The different seasonal ultrastructural characteristics of epithelial cells are considered in close relation to an absorbing function connecting with balance of different metabolisms.

The Pituitary of the Alosa fallax nilotica consists of a pars distalis, a pars intermedia and a pars nervosa. The pars distalis is divided into rostral and proximal. The pars nervosa extends also into proximal pars distalis. The rostral pars distalis, on the contrary in primitive Teleostei, has organized into cellular cords defining cavities or intercommunicating follicles. These latter finish into the oral adenohypophysial duct, which don't open in pharyngeal cavity. The cords contain three cell types: the columnar cells LTH, TSH cells and basal cells not yet functionally determined. The cord cells are separated from follicle cavity by an one layer of flat degranulated cells. The LTH cell, the chief cell type, together the TSH and basal cells shows evident cytologic differences in organelles of synthesis and secretion during the various stages of the reproductive migration. Besides globular and baton-shape projections are underlined in the apical cytoplasm of LTH cells. These structure, extending into follicle cavity, seem to dispatch sensory function probably. The proximal pars distalis consists of compact cords of gonadotropic cells (particularly active during the stage of migration from rivers to the sea) with inserted orangiophilic cells (probably STH) and phloxine cells: these latter cells are chiefly arranged at the periphery and immunocytochemical positive for the antibodies against ACTH. The pars intermedia contains cord of ACTH cells, particularly manifest during the periods of transit from sea water to fresh water and on the contrary, they are characterized by positive-ACTH dense granules. On the ground of ultrastructural aspects of vesicles, the pars nervosa shows three types of nervous fibers which correlate with neurosecretory hypothalamus and catecholaminergic dopaminergic fibers. The Authors think of underlining particularly that the all cells of rostral pars distalis and chiefly the LTH cells are involved significantly in the regulation of reproduction and hydro-mineral metabolic equilibrium.

The papillae of the tongue dorsal surface of the insectivorous, hibernating bats (Vespertilionidae and Rhinolophidae), whose function is mainly sensorial, consist of two circumvallate papillae, two foliate papillae, located at the side edges at the glossopalatine arch, and numerous fungiform papillae. The circumvallate and foliate papillae are characterized not only by their position, but also by presence of several taste buds which open through the external orifice of the gustatory canal into the cavity of the vallum, or furrow, which divides the two folds of the lingual mucosa. The fungiform papillae (extremely numerous on the whole dorsal surface) are characterized by an unusual arrangement (along 3 oblique lines on the anterior two-thirds and predominantly on the middle line of the tongue body) and by the presence of only one to three taste buds which open on the heavily keratinized dorsal epithelial surface. The taste buds are made up of sensory cells with a light or dark matrix; their apical cytoplasmic expansions are not found beyond the middle part of the gustatory canal, in contrast with the circumvallate and foliate papillae which protrude from the orifice of the gustatory pore. Comparisons with the papillae of other types of bats and Insectivora and evaluations of the morphological characteristics and their functional values (unusual areas of distribution of the papillae, apical cytoplasmic expansions and behaviour of microfolds observed under SEM) have been made in different environmental conditions and nutritional habits, with attention to the mechanical events in the course of feeding.

In primary or physiological ageing, the brain undergoes a 10% weight reduction. This datum was confirmed in vivo by radiological investigation and post mortem by morphological research (Grandi and Coll. 1990, 1990, 1991, 1991), that underscores the same reduction in the medulla oblongata and in the cerebellum. Morphological and cytohistological aspects of primary ageing have been considered for the inferior olivary nucleus and for the dentate nucleus in 41 male subjects, 32 belonging to the decades 7th, 8th, 9th, and 9 to the decades from the 3rd to the 6th. From the two latter structures, separated along standard cut surfaces, serial histological slices were carried out, and histochemical reactions were accomplished, together with immunohistochemistry, for synaptophysin, NF-2F11, NSE, S-100, GFAP, chromogranin. As the weight progressively decreased from the 7th to the 9th decade, it was noted neuronal loss, both in the inferior olivary nucleus, and in the dentate nucleus. Furthermore, the loss appeared to be followed by substitutive astroglial proliferation. Immunocytochemical reaction for synaptophysin revealed peculiar aspects. A consistently regular result of such method concerned the two nuclei studied, in primary ageing, thus allowing the interpretation of the perfect structure of synaptic vesicles as an indirect argument for neuronal plasticity.