Experimental paracoccidioidomycosis in high and low antibody responder mice of Selection IV-A

High (H) and low (L) responder mice were selected for their ability to produce antibodies against sheep and human erythrocytes (Selection IV-A). In this selection, the difference in antibody responsiveness between H and L lines (HIV-A and LIV-A mice, respectively) was shown to depend mainly on macrophage function. The more rapid catabolism of antigens by macrophages in L mice has been suggested as the main cause of the low antibody production. Due to this high macrophage activity, L animals have been described as more resistant than H animals to intracellular pathogens. These animals were utilized as an experimental model of paracoccidioidomycosis. HIV-A and LIV-A mice were infected with Paracoccidioides brasiliensis by the intravenous route. As expected, H mice were more susceptible to P. brasiliensis with a shorter survival time and higher levels of specific antibodies when compared to L mice. Contrasting with the survival time, the lungs, spleen and liver from H mice showed typical nodular granulomas containing epithelioid and giant cells and few fungi. on the other hand, in LN-A mice, the lesions of these organs were characterized by looser granulomas with irregular borders and the presence of a large number of fungi, However, the adrenal gland showed different lesion patterns. In H mice these lesions were extensive and characterized by loose granulomas with numerous fungi, while in LIV-A mice the lesions were small and limited to the cortex. Moreover the HIV-A mice presented higher levels of serum corticosterone when compared to LIV-A ones. The higher susceptibility of H mice could be attributed to the extensive lesions of the adrenal glands. These results suggest the use of the H line from the IV-A Selection as an experimental model for further studies of adrenal involvement in paracoccidioidomycosis.

Green Brazilian propolis action on macrophages and lymphoid organs of chronically stressed mice

Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well-being. The interaction between stress and immunity has been widely investigated, involving the neuroendocrine system and several organs. Assays using natural products in stress models deserve further investigation. Propolis immunomodulatory action has been mentioned and it has been the subject of scientific investigation in our laboratory. The aim of this study was to evaluate if and how propolis activated macrophages in BALB/c mice submitted to immobilization stress, as well as the histopathological analysis of the thymus, bone marrow, spleen and adrenal glands. Stressed mice showed a higher hydrogen peroxide (H2O2) generation by peritoneal macrophages, and propolis treatment potentiated H2O2 generation and inhibited nitric oxide (NO) production by these cells. Histopathological analysis showed no alterations in the thymus, bone marrow and adrenal glands, but increased germinal centers in the spleen. Propolis treatment counteracted the alterations found in the spleen of stressed mice. New research is being carried out in order to elucidate propolis immunomodulatory action during stress.

Nitric oxide synthase activity in tissues of the blowfly Chrysomya megacephala (Fabricius, 1794)

Although insects lack the adaptive immune response of the mammalians, they manifest effective innate immune responses, which include both cellular and Immoral components. Cellular responses are mediated by hemocytes, and Immoral responses include the activation of proteolytic cascades that initiate many events, including NO production. In mammals, nitric oxide synthases (NOSs) are also present in the endothelium, the brain, the adrenal glands, and the platelets. Studies on the distribution of NO-producing systems in invertebrates have revealed functional similarities between NOS in this group and vertebrates. We attempted to localize NOS activity in tissues of naive (UIL), yeast-injected (YIL), and saline-injected (SIL) larvae of the blowfly Chrysomya megacephala, using the NADPH diaphorase technique. Our findings revealed similar levels of NOS activity in muscle, fat body, Malpighian tubule, gut, and brain, suggesting that NO synthesis may not be involved in the immune response of these larval systems. These results were compared to many studies that recorded the involvement of NO in various physiological functions of insects.

INVOLVEMENT OF SWIMMING-INDUCED ACUTE STRESS IN THE SENSITIVITY OF RAT VAS-DEFERENS TO NOREPINEPHRINE

1. The effects of swimming-induced stress on rat sensitivity to norepinephrine were studied.2. Through microscopic analysis of the stomach from swimming stressed rats significant ulceration was observed, confirming that the stress situation was really present.3. Sensitivity to norepinephrine either in the presence or in the absence of cocaine and propranolol in acutely swimming stressed rats was not altered significantly.4. Bilateral adrenalectomy was performed in rats 2 days before swimming and acute stress resulted in a supersensitivity to norepinephrine, indicating that adrenal glands may, at least, partially mediate the sensitivity to this drug in vasa deferentia isolated from these animals.

Effects of glucose infusion on the endocrine, metabolic and cardiorespiratory responses to halothane anaesthesia of ponies

Glucose was infused intravenously into six ponies during halothane anaesthesia, to evaluate its effect on their endocrine response to anaesthesia. The ponies were premedicated with acepromazine, and anaesthesia was induced with thiopentone and maintained with halothane in oxygen for two hours. Glucose was infused to maintain the plasma glucose concentration above 20 mmol/litre. Anaesthesia was associated with hypothermia, a decrease in haematocrit, hypotension, hyperoxaemia, respiratory acidosis and an increase in the plasma concentrations of lactate and arginine vasopressin. The concentration of β-endorphin in plasma increased transiently after 20 minutes but there were no changes in concentrations of adrenocorticotrophic hormone, dynorphin, cortisol or catecholamines. These data suggest that the glucose infusion attenuated the normal adrenal response of ponies to halothane anaesthesia.

Baseline and stress-induced plasma corticosterone concentrations of mice selectively bred for high voluntary wheel running

The hypothalamic-pituitary-adrenal (HPA) axis is important in regulating energy metabolism and in mediating responses to stressors, including increasing energy availability during physical exercise. In addition, glucocorticoids act directly on the central nervous system and influence behavior, including locomotor activity. To explore potential changes in the HPA axis as animals evolve higher voluntary activity levels, we characterized plasma corticosterone (CORT) concentrations and adrenal mass in four replicate lines of house mice that had been selectively bred for high voluntary wheel running (HR lines) for 34 generations and in four nonselected control (C) lines. We determined CORT concentrations under baseline conditions and immediately after exposure to a novel stressor (40 min of physical restraint) in mice that were housed without access to wheels. Resting daytime CORT concentrations were approximately twice as high in HR as in C mice for both sexes. Physical restraint increased CORT to similar concentrations in HR and C mice; consequently, the proportional response to restraint was smaller in HR than in C animals. Adrenal mass did not significantly differ between HR and C mice. Females had significantly higher baseline and postrestraint CORT concentrations and significantly larger adrenal glands than males in both HR and C lines. Replicate lines showed significant variation in body mass, length, baseline CORT concentrations, and postrestraint CORT concentrations in one or both sexes. Among lines, both body mass and length were significantly negatively correlated with baseline CORT concentrations, suggesting that CORT suppresses growth. Our results suggest that selection for increased locomotor activity has caused correlated changes in the HPA axis, resulting in higher baseline CORT concentrations and, possibly, reduced stress responsiveness and a lower growth rate. © 2007 by The University of Chicago. All rights reserved.

Localization of myosin-Va in subpopulations of cells in rat endocrine organs

Myosin-Va is a Ca 2+/calmodulin-regulated unconventional myosin involved in the transport of vesicles, membranous organelles, and macromolecular complexes composed of proteins and mRNA. The cellular localization of myosin-Va has been described in great detail in several vertebrate cell types, including neurons, melanocytes, lymphocytes, auditory tissues, and a number of cultured cells. Here, we provide an immunohistochemical view of the tissue distribution of myosin-Va in the major endocrine organs. Myosin-Va is highly expressed in the pineal and pituitary glands and in specific cell populations of other endocrine glands, especially the parafollicular cells of the thyroid, the principal cells of the parathyroid, the islets of Langerhans of the pancreas, the chromaffin cells of the adrenal medulla, and a subpopulation of interstitial testicular cells. Weak to moderate staining has been detected in steroidogenic cells of the adrenal cortex, ovary, and Leydig cells. Myosin-Va has also been localized to non-endocrine cells, such as the germ cells of the seminiferous epithelium and maturing oocytes and in the intercalated ducts of the exocrine pancreas. These data provide the first systematic description of myosin-Va localization in the major endocrine organs of rat. © 2008 Springer-Verlag.

Cellular localization of androgen synthesis in equine granulosa-theca cell tumors: Immunohistochemical expression of 17α-hydroxylase/17,20-lyase cytochrome P450

Elevated blood testosterone concentrations, often accompanied by male-typical behaviors, is a common signalment of mares with granulosa-theca cell tumors (GCTCs), but no definitive information exists regarding the cellular differentiation of tumors associated with androgen secretion. This study was conducted to localize and thereby define the cellular expression of 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17), the enzyme most directly responsible for androgen synthesis, in 30 GTCTs and control tissues (gonads and adrenal glands) using immuno-histochemistry (IHC). Immuno-reactivity for P450c17 was evident in approximately half of 30 specimens examined, was most consistent in the interstitial cells surrounding existing or developing cysts, and was less intense in cells within cysts in the smaller proportion of specimens where this was observed. In control tissues, the expression of P450c17 was localized primarily in theca interna of normal ovarian follicles, in theca-lutein cells of some corpora lutea, but not in granulosa-lutein cells. Testicular interstitial cells and islands of adreno-cortical cells located in the adrenal medulla of the adrenal cortex further established the specificity of the antisera used. These data provided the first substantive evidence that polyhedral cells identified previously in GTCTs by histopathology have the potential to synthesize and secrete androgens, similar to theca interna and theca lutein cells in normal equine ovaries. © 2010 Elsevier Inc.

Visceral mast cell tumor and mastocythemia in a dog

Mast cell tumor manifests as a localized proliferation of mast cells in the skin, or less frequently as a systemic disorder, which may be accompanied by the presence of neoplastic mast cells in the peripheral blood (mastocythemia). In some cases, the neoplastic circulating mast cells originate in the bone marrow, designated as mast cell leukemia, rarely observed in dogs, or the cells may arise from visceral mast cell tumors, characterizing systemic mastocytosis. The aim of this report was to describe a case of a six-year-old female German shepherd dog presenting with history of anorexia, hematemesis and diarrhea. The blood work revealed intense mastocythemia (43%), with degranulated mast cells, and anisocytosis. At necropsy, white nodular lesions in the thymic region and an infiltrative mass in mesenteric and abdominal lymph nodes were observed. Those lymph nodes were enlarged and off-white. Histopathological examination revealed neoplastic mast cells in the liver, spleen, lymph nodes, kidneys, lungs, gastric and enteric mucosae, and adrenal glands. The clinical, hematological and histopathological findings were compatible with mastocythemia, associated with a moderately differentiated visceral mast cell tumor.

Ultrassonografia abdominal de cães e gatos hígidos, adultos e filhotes

Pós-graduação em Medicina Veterinária - FMVZ

Avaliação hormonal adrenocortical em cães com infecção natural por Ehrlichia canis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da própolis sobre parâmetros imunológicos de camundongos Balb/c submetidos a estresse crônico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparação das características e medidas ultrassonográficas das glândulas adrenais de cães e gatos filhotes saudáveis

The aim of the study was to analyze and compare the ultrasound characteristics of adrenal glands between healthy puppies and kittens by establishing standards of normality and references. Fifteen healthy crossbred puppies with mean weight of 3 kg and fifteen healthy crossbred kittens with mean weight of 2 kg, aged between five and six months, participated in the study. The animals were submitted to ultrasound exam of adrenal glands for visualization of their internal characteristics. The frequency of visualization of adrenal glands was 100% in kittens. In puppies the frequency was 75% for the right gland and 100% for the left gland. The puppy's adrenal gland, both right and left, were bigger in length (1.08 ± 0.01 cm, 1.11 ± 0.01 cm) and width (0.42 ± 0.02 cm, 0.45 ± 0.01 cm) in relation to kittens' adrenal gland length (0.64 ± 0.01 cm, 0.63 ± 0.01 cm) and width (0.30 ± 0.02 cm, 0.34 ± 0.01 cm). The adrenal gland of puppies and kittens was hypoechogenic to the surrounded fat, delimited by a hyperechogenic line and without distinction of the cortical and medullar region. The ultrasound dimensions of length and width of the adrenal glands, both right and left, were the same in puppies and kittens. The right and left puppies' adrenal glands were longer and wider than the kittens' glands.

Conventional and Doppler Abdominal Ultrasonography in Pacas (Cuniculus paca)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Implicações da disponibilidade de espaço no confinamento de bovinos de corte

Pós-graduação em Zootecnia - FCAV