Oral exposure to methylmercury modifies the prostatic microenvironment in adult rats

Methylmercury (MeHg) is an environmental pollutant that is highly toxic to the central nervous system. As its effects on male reproductive system are poorly understood, this study was carried out to analyse the effects of MeHg on the rat prostate. To evaluate the MeHg toxicity on ventral prostate, three groups of adult male Wistar rats received oral doses of 0.5, 1.0 and 3.0mg/kg MeHg, respectively, on a daily basis for 14days. A fourth group was used as a control. The prostate weight was decreased in rats treated orally with 0.5mg/kg MeHg compared to controls. Also, Hg concentration increased significantly in the prostate after treatments. There were reductions in serum testosterone levels and androgen receptor immunoreactivity in animals receiving 3.0mgMeHg/kg. The stereological data showed changes in the prostatic epithelial, stromal and luminal compartments which varied according to the different doses. Histopathological alterations, such as chronic inflammation, stratified epithelial hyperplasia and epithelial inflammatory reactive atypia, were observed in the 0.5mg/kg MeHg-treated group. Epithelial atrophy was observed in the 3.0mg/kg MeHg-treated group. In conclusion, the MeHg affects prostatic homoeostasis resulting in histopathological changes that may be relevant in the pathogenesis of prostatic disease.

Prenatal retinoic acid improves lung vascularization and VEGF expression in CDH rat

OBJECTIVE: We sought to investigate the effects of antenatal retinoic acid on the pulmonary vasculature and vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) expression in a nitrofen-induced congenital diaphragmatic hernia (CDH) model. STUDY DESIGN: Rat fetuses were exposed to nitrofen at gestational day 9.5 and/or all-trans retinoic acid (ATRA) at gestational days 18.5-20.5. We assessed lung growth, airway, and vascular morphometry. VEGF, VEGFR1, and VEGFR2 expression was analyzed by Western blotting and immunohistochemistry. Continuous data were analyzed by analysis of variance and Kruskal-Wallis test. RESULTS: CDH decreased lung to body weight ratio, increased mean linear intercept and mean transection length/airspace, and decreased mean airspace cord length. ATRA did not affect lung growth or morphometry. CDH increased proportional medial wall thickness of arterioles while ATRA reduced it. ATRA recovered expression of VEGF and receptors, which were reduced in CDH. CONCLUSION: Retinoic acid and VEGF may provide pathways for preventing pulmonary hypertension in CDH.

Gross morphology and topography of the digestive apparatus in rheas (Rhea americana americana)

Rodrigues M.N., Oliveira G.B., Silva R.S.S, Tivane C.T., Albuquerque J.F.G., Miglino M.A. & Oliveira M.F. 2012. [Gross morphology and topography of the digestive apparatus in rheas (Rhea americana americana).] Macroscopia e topografia do aparelho digestorio de emas (Rhea americana americana). Pesquisa Veterinaria Brasileira 32(7):681-686. Departamento de Cirurgia, Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, Cidade Universitaria, Av. Prof. Dr. Orlando Marques de Paiva 87, Sao Paulo, SP 05508270, Brazil. E-mail: marcio_medvet@hotmail.com Rheas are birds belonging to the ratites group and, among ostriches and emus, are the largest birds currently alive. In this work we studied the macroscopic aspects of rheas' digestive tract in order to provide important information to a better understanding of these birds' eating habits as well their anatomy. Twenty young animals aging between two and six months from the Centre for Wild Animals Multiplication (Cemas, scientific breeding license form Ibama no.1478912) were used. After dissection it was observed that their tongue was small and presented a rhomboid form, being disposed on the oral cavity floor, and inserted in its base by a frenulum. The esophagus was a rectilinear tube with elastic aspect and longitudinal elastic fibers, without dilation, which gives it an absence of crop. The proventriculus presented a fusiform form and the gastric ventricle showed and slightly oval form when filled, and was internally coated with a thick gastric cuticle. The small intestine was composed of three distinct regions: duodenum, jejunum and ileum. The duodenum had a light gray color and showed a "U" curved shaped. The jejunum was dark green, long and composed of several short loops arranged above each other. The ileum had a gray color and was connected with the jejunum. In ventral line to the rectum and cloaca, the ileum extended cranially, dorsally to the ascending duodenum. The large intestine was composed of two caeca, one right and one left, and colon-rectum and ileum were continuous with the cloaca. The structures of the rhea digestive tract resemble those described in the literature regarding to its shape and topography, even though rhea's caeca are well developed and relatively long.

ANATOMY OF NERITINA ZEBRA FROM GUYANA AND BRAZIL (MOLLUSCA: GASTROPODA: NERITIDAE)

Neritina zebra is a common brackish water gastropod living on muddy bottoms with poorly known morphological characters. The morphology, including the variety of colour and pattern of shells, and the anatomy are described. We mainly analyzed the animals collected in the estuary of the Ceara river, Ceara, Brazil, from "Parque Estadual do rio Coco", and specimens from other places deposited in institutional collections, from French Guyana (topotypes) to Sao Paulo. A complete anatomical description is performed, including illustration and discussion ninth concerned to systematics. Amongst the more important anatomical data are: heart diotocardian; kidneys solid; anterior esophagus with pair of ventral esophageal pouches; odontophore with 4 cartilages and 2 horizontal muscles (m6, m6a); males with penis dorsal-right to snout, bearing a terminal papilla; pallial oviduct triaulic, possessing 3 pallial apertures.

Motor cortex stimulation inhibits thalamic sensory neurons and enhances activity of PAG neurons: Possible pathways for antinociception

Motor cortex stimulation is generally suggested as a therapy for patients with chronic and refractory neuropathic pain. However, the mechanisms underlying its analgesic effects are still unknown. In a previous study, we demonstrated that cortical stimulation increases the nociceptive threshold of naive conscious rats with opioid participation. In the present study, we investigated the neurocircuitry involved during the antinociception induced by transdural stimulation of motor cortex in naive rats considering that little is known about the relation between motor cortex and analgesia. The neuronal activation patterns were evaluated in the thalamic nuclei and midbrain periaqueductal gray. Neuronal inactivation in response to motor cortex stimulation was detected in thalamic sites both in terms of immunolabeling (Zif268/Fos) and in the neuronal firing rates in ventral posterolateral nuclei and centromedian-parafascicular thalamic complex. This effect was particularly visible for neurons responsive to nociceptive peripheral stimulation. Furthermore, motor cortex stimulation enhanced neuronal firing rate and Fos immunoreactivity in the ipsilateral periaqueductal gray. We have also observed a decreased Zif268, delta-aminobutyric acid (GABA), and glutamic acid decarboxylase expression within the same region, suggesting an inhibition of GABAergic interneurons of the midbrain periaqueductal gray, consequently activating neurons responsible for the descending pain inhibitory control system. Taken together, the present findings suggest that inhibition of thalamic sensory neurons and disinhibition of the neurons in periaqueductal gray are at least in part responsible for the motor cortex stimulation-induced antinociception. (C) 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Contribution of the retrotrapezoid nucleus/parafacial respiratory region to the expiratory-sympathetic coupling in response to peripheral chemoreflex in rats

Moraes DJ, Dias MB, Cavalcanti-Kwiatkoski R, Machado BH, Zoccal DB. Contribution of retrotrapezoid nucleus/parafacial respiratory region to the expiratory-sympathetic coupling in response to peripheral chemoreflex in rats. J Neurophysiol 108: 882-890, 2012. First published May 16, 2012; doi:10.1152/jn.00193.2012.-Central mechanisms of coupling between respiratory and sympathetic systems are essential for the entrainment between the enhanced respiratory drive and sympathoexcitation in response to hypoxia. However, the brainstem nuclei and neuronal network involved in these respiratory-sympathetic interactions remain unclear. Here, we evaluated whether the increase in expiratory activity and expiratory-modulated sympathoexcitation produced by the peripheral chemoreflex activation involves the retrotrapezoid nucleus/parafacial respiratory region (RTN/pFRG). Using decerebrated arterially perfused in situ rat preparations (60-80 g), we recorded the activities of thoracic sympathetic (tSN), phrenic (PN), and abdominal nerves (AbN) as well as the extracellular activity of RTN/pFRG expiratory neurons, and reflex responses to chemoreflex activation were evaluated before and after inactivation of the RTN/pFRG region with muscimol (1 mM). In the RTN/pFRG, we identified late-expiratory (late-E) neurons (n = 5) that were silent at resting but fired coincidently with the emergence of late-E bursts in AbN after peripheral chemoreceptor activation. Bilateral muscimol microinjections into the RTN/pFRG region (n = 6) significantly reduced basal PN frequency, mean AbN activity, and the amplitude of respiratory modulation of tSN (P < 0.05). With respect to peripheral chemoreflex responses, muscimol microinjections in the RTN/pFRG enhanced the PN inspiratory response, abolished the evoked late-E activity of AbN, but did not alter either the magnitude or pattern of the tSN reflex response. These findings indicate that the RTN/pFRG region is critically involved in the processing of the active expiratory response but not of the expiratory-modulated sympathetic response to peripheral chemoreflex activation of rat in situ preparations.

Hérnias abdominais e inguinais em pacientes cirróticos: qual é a melhor conduta?

INTRODUÇÃO: Tradicionalmente os procedimentos abdominais eletivos em pacientes cirróticos têm sido amplamente desencorajados graças à elevada morbi-mortalidade consequente às complicações da cirrose, descritas por diversos autores. Outros serviços, em contrapartida, obtiveram resultados distintos, advogando a favor de cirurgia eletiva. MÉTODOS: Uma revisão de artigos utilizando-se a palavras "abdominal wall hernia" e "cirrhotic patients" foi realizada na base de dados PubMed. Dos resultados obtidos, 28 artigos foram considerados para elaboração desta revisão. RESULTADOS: Pôde-se observar que a incidência de hérnias em parede abdominal é relativamente elevada em pacientes cirróticos, sendo que muitas delas têm evolução desfavorável e requerem tratamento cirúrgico específico. Com o advento do sistema de alocação de órgãos baseados no escore de MELD, muitos centros estão repensando suas condutas em situações como esta, dado que muitos dos pacientes em questão encontram-se em lista de espera para transplante hepático. Dessa forma a cirurgia eletiva tem conquistado maior papel no manejo desta condição com intuito de diminuir morbi-mortalidade nesses pacientes. Além disso, a qualidade de vida mostrou-se um importante fator a ser considerado, estando muito prejudicada nesta condição. CONCLUSÃO: Poucos estudos com grandes amostragens foram conduzidos até o momento e não há consenso sobre qual conduta é a mais indicada levando em consideração taxas de morbi-mortalidade.

Horse spleen segmentation technique as large animal model of preclinical trials

The parenchymal distribution of the splenic artery was studied in order to obtain anatomical basis for partial splenectomy. Thirty two spleens were studied, 26 spleens of healthy horses weighing 320 to 450kg, aged 3 to 12 years and 6 spleens of fetus removed from slaughterhouse. The spleens were submitted to arteriography and scintigraphy in order to have their vascular pattern examined and compared to the external aspect of the organ aiming establish anatomo-surgical segments. All radiographs were photographed with a digital camera and the digital images were submitted to a measuring system for comparative analysis of areas of dorsal and ventral anatomo-surgical segments. Anatomical investigations into the angioarchitecture of the equine spleen showed a paucivascular area, which coincides with a thinner external area, allowing the organ to be divided in two anatomo-surgical segments of approximately 50% of the organ each.

Chronic unpredictable mild stress alters an anxiety-related defensive response, Fos immunoreactivity and hippocampal adult neurogenesis

Previous results show that elevated T-maze (ETM) avoidance responses are facilitated by acute restraint. Escape, on the other hand, was unaltered. To examine if the magnitude of the stressor is an important factor influencing these results, we investigated the effects of unpredictable chronic mild stress (UCMS) on ETM avoidance and escape measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to map areas activated by stress exposure in response to ETM avoidance and escape performance. Additionally, the effects of the UCMS protocol on the number of cells expressing the marker of migrating neuroblasts doublecortin (DCX) in the hippocampus were investigated. Corticosterone serum levels were also measured. Results showed that UCMS facilitates ETM avoidance, not altering escape. In unstressed animals, avoidance performance increases Fos-ir in the cingulate cortex, hippocampus (dentate gyrus) and basomedial amygdala, and escape increases Fos-ir in the dorsolateral periaqueductal gray and locus ceruleus. In stressed animals submitted to ETM avoidance, increases in Fos-ir were observed in the cingulate cortex, ventrolateral septum, hippocampus, hypothalamus, amygdala, dorsal and median raphe nuclei. In stressed animals submitted to ETM escape, increases in Fos-ir were observed in the cingulate cortex, periaqueductal gray and locus ceruleus. Also, UCMS exposure decreased the number of DCX-positive cells in the dorsal and ventral hippocampus and increased corticosterone serum levels. These data suggest that the anxiogenic effects of UCMS are related to the activation of specific neurobiological circuits that modulate anxiety and confirm that this stress protocol activates the hypothalamus-pituitary-adrenal axis and decreases hippocampal adult neurogenesis.

Hypothyroidism in adult male rats alters posttranscriptional mechanisms of luteinizing hormone biosynthesis

BACKGROUND: Studies in men are not consistent regarding the effects of thyroid hormone on the production of gonadotropins. In hypothyroidism consequent to diverse causes, an increase or no change in serum luteinizing hormone (LH) have been reported. The attempt to explain the mechanisms involved in this pathology using rats as an experimental model also seems to repeat this divergence, since hypothyroidism has been shown to induce hypogonadotropic hypogonadism, a hypergonadotropic state, or not to affect the basal levels of LH. Notably, the promoter region of the gene encoding the Lh beta subunit and GnRH (gonadotropin-releasing factor) does not contain a thyroid responsive element. Therefore, we investigated the hypothesis that, in male rats, posttranscriptional mechanisms of LH synthesis are altered in hypothyroidism. We also attempted to determine if hypothyroidism directly affects testicular function in male rats. METHODS: Male Wistar rats, 60 days old, were thyroidectomized or sham-operated. After 20 days, they were decapitated, and the pituitaries were collected and analyzed for Lh mRNA, LH content, poly(A) tail length, and polysome profile. The testes were collected and analyzed for Lh receptor mRNA, LH receptor content, and histology using morphometric analyses. The testis, epididymis, seminal vesicle, and ventral prostate were weighed, and serum concentrations of LH, testosterone, thyrotropin (TSH), and triiodothyronine (T3) were measured. RESULTS: Hypothyroidism was associated, in the pituitary, with an increase in Lh mRNA expression, a reduction in Lh mRNA poly(A) tail length, a reduction in the number of LH transcripts associated with polysomes. Pituitary LH was decreased but serum LH was increased from 102 to 543 pg/mL. Despite this, serum testosterone concentrations were decreased from 1.8 to 0.25 ng/mL. A decreased germinative epithelium height of the testes and a reduced weight of androgen-responsive tissues were observed (ventral prostrate: 74 vs. 23 mg/100 g body weight [BW]; seminal vesicle undrained: 280 vs. 70 mg/100 g BW; and seminal vesicle drained: 190 vs. 60 mg/100 g BW). CONCLUSIONS: Hypothyroidism in adult male rats has dual effects on the pituitary testicular axis. It alters posttranscriptional mechanisms of LH synthesis and probably has a direct effect on testicular function. However, these data suggest the possibility that reduced LH bioactivity may account in part for impaired testicular function.