Glucocorticoids in vivo induce both insulin hypersecretion and enhanced glucose sensitivity of stimulus-secretion coupling in isolated rat islets

Although glucocorticoids are widely used as antiinflammatory agents in clinical therapies, they may cause serious side effects that include insulin resistance and hyperinsulinemia. To study the potential functional adaptations of the islet of Langerhans to in vivo glucocorticoid treatment, adult Wistar rats received dexamethasone (DEX) for 5 consecutive days, whereas controls (CTL) received only saline. The analysis of insulin release in freshly isolated islets showed an enhanced secretion in response to glucose in DEX-treated rats. The study of Ca2 2+ signals by fluorescence microscopy also demonstrated a higher response to glucose in islets from DEX-treated animals. However, no differences in Ca2 2+signals were found between both groups with tolbutamide or KCl, indicating that the alterations were probably related to metabolism. Thus, mitochondrial function was explored by monitoring oxidation of nicotinamide dinucleotide phosphate autofluorescence and mitochondrial membrane potential. Both parameters revealed a higher response to glucose in islets from DEX-treated rats. The mRNA and protein content of glucose transporter-2, glucokinase, and pyruvate kinase was similar in both groups, indicating that changes in these proteins were probably not involved in the increased mitochondrial function. Additionally,weexplored the status of Ca2 2+-dependent signaling kinases. Unlike calmodulin kinase II, we found an augmented phosphorylation level of protein kinase Cα as well as an increased response of the phospholipase C/inositol 1,4,5-triphosphate pathway in DEX-treated rats. Finally, an increased number of docked secretory granules were observed in the β-cells of DEX animals using transmission electron microscopy. Thus, these results demonstrate that islets from glucocorticoid-treated rats develop several adaptations that lead to an enhanced stimulus-secretion coupling and secretory capacity. Copyright © 2010 by The Endocrine Society.

rastreamento histoquímico, fitoquímico e biológico de folhas de Plinia cauliflora (DC.) Kausel (Myrtaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Exercise at anaerobic threshold intensity and insulin secretion by isolated pancreatic islets of rats

To evaluate the effect of acute exercise and exercise training at the anaerobic threshold (AT) intensity on aerobic conditioning and insulin secretion by pancreatic islets, adult male Wistar rats were submitted to the lactate minimum test (LMT) for AT determination. Half of the animals were submitted to swimming exercise training (trained), 1 h/day, 5 days/week during 8 weeks, with an overload equivalent to the AT. The other half was kept sedentary. At the end of the experimental period, the rats were submitted to an oral glucose tolerance test and to another LMT. Then, the animals were sacrificed at rest or immediately after 20 minutes of swimming exercise at the AT intensity for pancreatic islets isolation. At the end of the experiment mean workload (% bw) at AT was higher and blood lactate concentration (mmol/L) was lower in the trained than in the control group. Rats trained at the AT intensity showed no alteration in the areas under blood glucose and insulin during OGTT test. Islet insulin content of trained rats was higher than in the sedentary rats while islet glucose uptake did not differ among the groups. The static insulin secretion in response to the high glucose concentration (16.7 mM) of the sedentary group at rest was lower than the sedentary group submitted to the acute exercise and the inverse was observed in relation to the trained groups. physical training at the AT intensity improved the aerobic condition and altered insulin secretory pattern by pancreatic islets. © 2010 Landes Bioscience.

Retention mucocele on the lower lip associated with inadequate use of pacifier

Mucocele forms because of salivary gland mucous extravasation or retention and is usually related to trauma in the area of the lower lips. Ruptured ducts release the mucous that accumulates into adjacent tissues, leading to swelling. This report describes a large mucocele involving the lower lip, which was produced in a child by incorrect use of a pacifier. A few important concepts are discussed to help clinicians in the diagnosis and treatment of this pathology. © 2010 Dermatology Online Journal.

Estruturas secretoras de Pavonia alnifolia (Malvaceae), uma espécie ameaçada de extinção

Malvaceae shows a rich morphological diversity of secretory structures, which are of great ecological and taxonomical relevance. Nonetheless, until the present moment, studies on the secretory structures of the studied species were not found. Pavonia alnifolia A.St.-Hil. is endangered species of extinction with restricted distribution within the restingas of Rio the Janeiro and Espírito Santo, Brazil. The species were collected from the former and usual techniques on plant anatomy and histochemistry were performed. Anatomical and histochemical studies of the secretory structures of Pavonia alnifolia are showed in this work. The presence of external and internal secretory structures of mucilage in many organs, idioblasts of phenolic and lipid substances and floral nectaries what is a very important adaptative survival mechanism of the species in the restinga environment. The secretion produced by nectaries is envolved with maintenance of interations with visiting insects, what constitutes a good model to experimental studies with an ecological approach.

Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

Imbalance in the resident microbiota may promote the growth of opportunistic microorganisms, such as yeasts of Candida genus and the development of diseases, especially in aged people. This study evaluated whether the consumption of the probiotic Yakult LB® (Lactobacillus casei and Bifidobacterium breve) was able to influence on the specific immunological response against Candida and on the presence of these yeasts in the oral cavity of 42 healthy aged individuals. Saliva samples were collected before and after the probiotic use for 30 days, 3 times a week. The samples were plated in Dextrose Saboraud Agar with chloramphenicol, the colony-forming units (CFU/mL) were counted and the Candida species were identified. Anti-Candida IgA analysis was conducted using the ELISA technique. ANOVA and Student's t-test were used for normally distributed data and the Wilcoxon test was used for data with non-normal distribution (α=0.05). The results showed a statistically significant reduction (p<0.05) in Candida prevalence (from 92.9% to 85.7%), in CFU/mL counts of Candida and in the number of non-albicans species after consumption of the probiotic. Immunological analysis demonstrated a significant increase (p<0.05) in anti-Candida IgA levels. In conclusion, probiotic bacteria reduced Candida numbers in the oral cavity of the elderly and increased specific secretory immune response against these yeasts, suggesting its possible use in controlling oral candidosis.

Agelaia MP-I: A peptide isolated from the venom of the social wasp, Agelaia pallipes pallipes, enhances insulin secretion in mice pancreatic islets

Peptides isolated from animal venoms have shown the ability to regulate pancreatic beta cell function. Characterization of wasp venoms is important, since some components of these venoms present large molecular variability, and potential interactions with different signal transduction pathways. For example, the well studied mastoparan peptides interact with a diversity of cell types and cellular components and stimulate insulin secretion via the inhibition of ATP dependent K + (K ATP) channels, increasing intracellular Ca 2+ concentration. In this study, the insulin secretion of isolated pancreatic islets from adult Swiss mice was evaluated in the presence of synthetic Agelaia MP-I (AMP-I) peptide, and some mechanisms of action of this peptide on endocrine pancreatic function were characterized. AMP-I was manually synthesized using the Fmoc strategy, purified by RP-HPLC and analyzed using ESI-IT-TOF mass spectrometry. Isolated islets were incubated at increasing glucose concentrations (2.8, 11.1 and 22.2 mM) without (Control group: CTL) or with 10 μM AMP-I (AMP-I group). AMP-I increased insulin release at all tested glucose concentrations, when compared with CTL (P < 0.05). Since molecular analysis showed a potential role of the peptide interaction with ionic channels, insulin secretion was also analyzed in the presence of 250 μM diazoxide, a K ATP channel opener and 10 μM nifedipine, a Ca 2+ channel blocker. These drugs abolished insulin secretion in the CTL group in the presence of 2.8 and 11.1 mM glucose, whereas AMP-I also enhanced insulin secretory capacity, under these glucose conditions, when incubated with diazoxide and nifedipine. In conclusion, AMP-I increased beta cell secretion without interfering in K ATP and L-type Ca 2+ channel function, suggesting a different mechanism for this peptide, possibly by G protein interaction, due to the structural similarity of this peptide with Mastoparan-X, as obtained by modeling. © 2012 Elsevier Ltd.

Interdisciplinary approach to the management of Ewing sarcoma: A case report

Ewing sarcoma is a common primary bone malignancy occurring in childhood and adolescence. This case report describes a 4-year-old female patient who had Ewing sarcoma in the left clavicular region. The patient underwent total excision of the left clavicle and subsequently developed periodontitis and multiple carious lesions after chemotherapy. Caries risk and salivary flow rate tests were performed, followed by periodontal treatment, topical fluoride application, restoration of caries, and oral hygiene instruction. The care of this patient demonstrates that an interdisciplinary approach is essential to eliminate all foci of infection, minimize morbidity, and improve the patient's general health before, during, and after oncological treatment. © 2012 Special Care Dentistry Association and Wiley Periodicals, Inc.

The role of fibres and the hypodermis in Compositae melanin secretion

Melanins are dark, insoluble pigments that are resistant to concentrated acids and bleaching by oxidising agents. Phytomelanin (or phytomelan) is present in the seed coat of some Asparagales and in the fruits of some Compositae. In Compositae fruits, melanin is deposited in the schizogenous spaces between the hypodermis and underlying fibrous layer. Phytomelanin in Compositae is poorly understood, and there are only speculations regarding the cells that produce the pigment and the cellular processes involved in the secretion and polymerisation of phytomelanin. This report describes the cellular processes involved in the secretion of phytomelanin in the pericarp of Praxelis diffusa, a species with a structure typical of the family. The ovaries and fruits at different stages were fixed and processed according to the standard methods of studies of light microscopy and transmission electron microscopy. Hypodermal cells have abundant rough endoplasmic reticulum and mitochondria, and the nuclei have chromatin that is less dense than other cells. These characteristics are typical of cells that synthesise protein/amino acids and suggest no carbohydrate secretion. The fibres, however, have a dense cytoplasm rich in the Golgi bodies that are associated with vesicles and smooth endoplasmic reticulum, common characteristics of carbohydrate secretory cells. Our results indicate that the hypodermal cells are not responsible for the secretion of phytomelanin, as previously described in the literature; in contrast, this function is assigned to the adjacent fibres, which have an organisation typical of cells that secrete carbohydrates. © 2012 Elsevier Ltd.

Estrogen receptors alpha and beta in male and female gerbil prostates

The Mongolian gerbil (Meriones unguiculatus, Gerbilinae: Muridae) is useful for prostate studies, because both males and females spontaneously develop prostatic disorders with age. Estrogens regulate prostate homeostasis via two estrogen receptors, ER alpha (ESR1) and ER beta (ESR2), but the cellular distribution and regulation of these receptors in the gerbil prostate has not been described. Both receptors were localized by immunohistochemistry in the ventral prostate of intact male and female gerbils, in males 7 and 21 days after castration, and in females treated with testosterone for 7 and 21 days. In male and female adult gerbils, ER alpha was detected mainly in prostatic stromal cells, whereas ER beta was present mostly in secretory and basal cells. More ER alpha-positive stromal cells were found in females than in males, as was a reduction toward the male value in females treated with testosterone. Castration did not alter ER alpha expression. Testosterone was necessary for maintenance of ER beta in the male prostate epithelium: ER beta expression declined markedly in prostates of males older than 1 yr, and castration of 4-mo-old males caused a reduction in ER beta to levels seen in 1-yr-old males. Because ER beta is an antiproliferative receptor, its loss with age may predispose the aging gerbil to proliferative diseases of the prostate. © 2013 by the Society for the Study of Reproduction, Inc.

The reproductive cycle of the male sleep snake Sibynomorphus mikanii (Schlegel, 1837) from southeastern brazil

This study describes the male reproductive cycle of Sibynomorphus mikanii from southeastern Brazil considering macroscopic and microscopic variables. Spermatogenesis occurs during spring-summer (September-December) and spermiogenesis or maturation occurs in summer (December-February). The length and width of the kidney, the tubular diameter, and the epithelium height of the sexual segment of the kidney (SSK) are larger in summer-autumn (December-May). Histochemical reaction of the SSK [periodic acid-Schiff (PAS) and bromophenol blue (BB)] shows stronger results during summer-autumn, indicating an increase in the secretory activity of the granules. Testicular regression is observed in autumn and early winter (March-June) when a peak in the width of the ductus deferens occurs. The distal ductus deferens as well as the ampulla ductus deferentis exhibit secretory activities with positive reaction for PAS and BB. These results suggest that this secretion may nourish the spermatozoa while they are being stored in the ductus deferens. The increase in the Leydig cell nuclear diameter in association with SSK hypertrophy and the presence of sperm in the female indicate that the mating season occurs in autumn when testes begin to decrease their activity. The peak activity of Leydig cells and SSK exhibits an associated pattern with the mating season. However, spermatogenesis is dissociated of the copulation characterizing a complex reproductive cycle. At the individual level, S. mikanii males present a continuous cyclical reproductive pattern in the testes and kidneys (SSK), whereas at the populational level the reproductive pattern may be classified as seasonal semisynchronous. © 2012 Wiley Periodicals, Inc.

Effects of exposure to estradiol and estradiol plus testosterone on the mongolian gerbil (Meriones unguiculatus) female prostate

The female prostate is a differentiated organ found in several mammal species, including humans and rodents. This gland has been related to important functions on female reproductive biology. Although the factors, which regulate prostate's development and activity are not well known, its functionality has been related to steroid hormones. It is well established that cyclic changes of estradiol and progesterone levels promote histophysiological adaptations of the whole female body. In contrast, only a few is found about those adaptations in female prostate. Thus, this study aimed to evaluate the effect of estradiol and estradiol+testosterone association on gerbil female prostate in order to verify, which hormonal associations are necessary to its homeostasis. For this, adult females had the ovaries surgically removed. After recovering, they received estradiol and estradiol+testosterone doses through 30 days, each 48 h. The prostatic tissue underwent morphological and morphometric-estereological analysis. Hormonal restriction caused great gland involution and decreased secretory activity, aspects that were reverted by exposure to estradiol and estradiol+testosterone. However, these hormones were not able to re-establish the normal prostate histoarchitecture. The immunoreaction of steroid receptors (ER-α, ER-β, and AR) responded differently among the experimental and control groups, and PCNA assay showed a decrease in epithelial cell proliferation within groups that had hormone privation. Therefore, we conclude that estradiol and testosterone are able to influence prostate morphophysiology and the maintenance of gland homeostasis depends on a balance among these and other hormones. © 2013 Wiley Periodicals, Inc.

Progesterone restores the female prostate activity in ovariectomized gerbil and may act as competitor of testosterone in intraprostatic environment

Aims Little is known about the effect of progesterone on gerbil female prostate. It is known that normal oscillation in the progesterone and estradiol levels during the estrous cycle phases influence the morphophysiology of this gland. The present study aims to evaluate the isolated effect of prolonged administration of progesterone combined or not with testosterone on the prostate of ovariectomized female gerbil. Main methods To observe the morphological changes caused by castration in the prostate of different groups stereologic analyses of all prostate compartments, analysis of nuclear area and perimeter, and morphometric measurements of epithelial and smooth muscle cells layers were used. In addition, immunocytochemistry was performed to investigate the distribution of the androgen, estrogen alfa and beta and progesterone receptors in different prostatic compartments. Key findings This study demonstrated that both treatments partially recovered the structure of the gland. In the group treated with progesterone plus testosterone a higher incidence of epithelial and stromal disorders occurred, besides the absence of secretory activity. Thus, treatment only with progesterone showed better results in the restoration of glandular homeostasis mainly seen by the regulation of the secretory activity. Significance Collectively, the findings of this study indicate that progesterone may have a significant role on the maintenance of prostate morphophysiology, and showed an interesting evidence of hormonal competition between progesterone and testosterone. © 2013 Elsevier Inc.

Morphology and biometric of the vesicular and bulbourethral glands in castrated and non-castrated Santa Ines breed sheep

Introduction: The purpose of this paper is to determine the topography, biometry and light microscopy image of the vesicular and bulbourethral glands in order to analyze morphologic features of the accessory sexual glands in castrated and non-castrated animals. Materials and Methods: The morphology of the accessory sexual glands was investigated in 14 adult Santa Ines breed sheep, weighing 32 kg, on average. Six of them were castrated, and eight, non-castrated. For macroscopic study, the description of these two glands was carried out, as well as dissection and biometry study. Moreover, weight, length, height and width measurements were evaluated. For histological analysis, the vesicular and bulbourethral glands were sampled. Results: The topography of the reproductive glands was similar to bovine species. However, lower macroscopic measurements (p < 0,05) in the glands of the castrated sheep were evidenced when compared with the non-castrated ones. Characteristics such as shape of the glands, composition of the layer mucosa, the lamina propria, muscular, the excretory ducts and the adventitia were determined. Conclusion: Sheep castration promoted changes in the biometric measures of the glands, which were lower in castrated animals. The morphological and biometric characteristics of the vesicular and bulbourethral glands in sheep were determined.

Estudos morfológicos e histoquímicos do tubo digestivo de Hemisorubim platyrhynchos (Valenciennes, 1840)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)