Abdominal TRPV1 channel desensitization enhances stress-induced hyperthermia during social stress in rats.

AIMS: In rats, stress-induced hyperthermia caused by social interaction depends on brown adipose tissue (BAT) thermogenesis and peripheral vasoconstriction. However, the peripheral mechanisms responsible for regulating the level of hyperthermia during social stress are still unknown. The transient receptor potential vanilloid 1 (TRPV1) subfamily, expressed in sensory and visceral neurons, can serve as a thermoreceptor. Here, we tested the hypothesis that the abdominal TRPV1 is essential in regulating stress-induced hyperthermia during social stress. MAIN METHODS: Male Wistar rats received an intraperitoneal injection of Resiniferatoxin (RTX) - an ultra-potent capsaicin analog, (i.e., to desensitize the TRPV1 channels) or vehicle. Seven days later, we evaluated the effects of abdominal TRPV1 channels desensitization on core body temperature (CBT), brown adipose tissue (BAT) temperature, tail skin temperature, and heart rate (HR) of rats subjected to a social stress protocol. KEY FINDINGS: We found abdominal TRPV1 desensitization increased CBT and BAT temperature but did not change tail skin temperature and HR during rest. However, under social stress, we found that abdominal TRPV1 desensitization heightened the increase in CBT and BAT caused by stress. Also, it abolished the increase in tail skin temperature that occurs during and after social stress. TRPV1 desensitization also delayed the HR recovery after the exposure to the social stress. SIGNIFICANCE: These results show that abdominal TRPV1 channels desensitization heightens stress-induced hyperthermia, causing heat dissipation during and after social stress, enabling optimal thermal control during social encounters.

Cutaneous Leishmaniosis caused by Leishmania martiniquensis in a Horse in Florida.

We report a new case of cutaneous leishmaniosis caused by Leishmania (Mundinia) martiniquensis in a horse in Florida, USA. A 10-year-old neutered male Quarter horse was presented with multifocal to coalescing, raised, ulcerated and oozing, non-healing wounds on both pinnae of several weeks' duration. After a few months, the lesions regressed spontaneously. Biopsies of the lesions were performed with microscopical findings of epidermal hyperplasia with multifocal ulceration and focally extensive, dermal pyogranulomatous inflammation with numerous intact and degenerate neutrophils being surrounded by epithelioid macrophages, lymphocytes and plasma cells, as well as rare eosinophils. Within the macrophages, and freely within the inflammatory infiltrate, were small (2-4 µm) round, basophilic protozoal organisms. Immunohistochemistry and colourimetric in-situ hybridization were positive for amastigote forms of Leishmania spp. The species L. martiniquensis was identified by polymerase chain reaction targeting the ITS-1 gene performed with extracts from formalin-fixed and paraffin wax-embedded samples of skin lesions. L. martiniquensis causes an ulcerative pyogranulomatous dermatitis in horses with spontaneous healing. This second autochthonous case in Florida, 5 years after the first case, suggests that this parasite may have become endemic in this state.

Association of high-fat diet with neuroinflammation, anxiety-like defensive behavioral responses, and altered thermoregulatory responses in male rats.

Overweight and obesity are a worldwide pandemic affecting billions of people. These conditions have been associated with a chronic low-grade inflammatory state that is recognized as a risk factor for a range of somatic diseases as well as neurodevelopmental disorders, anxiety disorders, trauma- and stressor-related disorders, and affective disorders. We previously reported that the ingestion of a high-fat diet (HFD; 45% fat kcal/g) for nine weeks was capable of inducing obesity in rats in association with increased reactivity to stress and increased anxiety-related defensive behavior. In this study, we conducted a nine-week diet protocol to induce obesity in rats, followed by investigation of anxiety-related defensive behavioral responses using the elevated T-maze (ETM), numbers of FOS-immunoreactive cells after exposure of rats to the avoidance or escape task of the ETM, and neuroinflammatory cytokine expression in hypothalamic and amygdaloid nuclei. In addition, we investigated stress-induced cutaneous thermoregulatory responses during exposure to an open-field (OF). Here we demonstrated that nine weeks of HFD intake induced obesity, in association with increased abdominal fat pad weight, increased anxiety-related defensive behavioral responses, and increased proinflammatory cytokines in hypothalamic and amygdaloid nuclei. In addition, HFD exposure altered avoidance- or escape task-induced FOS-immunoreactivity within brain structures involved in control of neuroendocrine, autonomic, and behavioral responses to aversive stimuli, including the basolateral amygdala (BLA) and dorsomedial (DMH), paraventricular (PVN) and ventromedial (VMH) hypothalamic nuclei. Furthermore, rats exposed to HFD, relative to control diet-fed rats, responded with increased tail skin temperature at baseline and throughout exposure to an open-field apparatus. These data are consistent with the hypothesis that HFD induces neuroinflammation, alters excitability of brain nuclei controlling neuroendocrine, autonomic, and behavioral responses to stressful stimuli, and enhances stress reactivity and anxiety-like defensive behavioral responses.

Comparison of the Sensitivity of Three Methods for the Early Diagnosis of Sporotrichosis in Cats.

Sporotrichosis is caused by species of fungi within the Sporothrix schenckii complex that infect man and animals. In Rio de Janeiro, Brazil, an epidemic has been observed since 1998, with most of the cases being related to transmission from infected cats. Although the definitive diagnosis of feline sporotrichosis is made by fungal culture, cytopathological and histopathological examinations are used routinely, because the long culture period may delay treatment onset. However, alternative methods are desirable in cases of low fungal burden. Immunohistochemistry (IHC) has been described as a sensitive method for diagnosing human and canine sporotrichosis, but there are no reports of its application to cats. The aim of this study was to analyse the sensitivity of cytopathological examination (Quick Panoptic method), histopathology (Grocott silver stain) and anti-Sporothrix IHC by blinded comparisons, using fungal culture as the reference standard. Samples were collected from 184 cats with sporotrichosis that exhibited skin ulcers. The sensitivities of Grocott silver stain, cytopathological examination and IHC were 91.3%, 87.0% and 88.6%, respectively. Grocott silver stain showed the best performance. IHC showed high sensitivity, as did cytopathological examination and these may be considered as alternative methodologies. When the three methods were combined, the diagnosis was established in 180 (97.8%) out of 184 cases. Taken together, these findings indicate the need to implement these methods as routine tools for the early diagnosis of sporotrichosis in cats, notably when fungal culture is not available.

Philometra saltatrix (Nematoda: Philometridae) in the ovary of the bluefish, Pomatomus saltatrix (Linnaeus, 1766), off the coast of the state of Rio de Janeiro, Brazil.

The aims of the present study were to identify and describe the occurrence of nematode parasites in the gonads of bluefish Pomatomus saltatrix from off the coast of the state of Rio de Janeiro, Brazil. Only females were found to be parasitized by the nematodes, which were identified as P. saltatrix using morphological, morphometric and molecular data. Infection of female bluefish by this nematode had the following values: prevalence, 48.7%; mean intensity, 2.6; mean abundance, 1.3; and range of infection, 1-10 specimens. Histopathological examination of transverse and longitudinal sections of the parasitized ovaries showed nematodes at different stages of development among oocytes, but no indication of any associated inflammatory reaction. The presence of nematodes in the ovaries of bluefish is an important indication of fish hygiene, and parasitized fish are usually rejected by consumers because of their repugnant appearance.

Avaliação da confiabilidade entre dois observadores em exames citopatológico e imunocitoquímico de aspirado de medula óssea no diagnóstico da leishmaniose visceral canina / Reliability evaluation between two evaluators in the cytopathologic and immunocytochemical exams from bone marrow aspirate in the canine visceral leishmaniasis diagnosis

Visceral leishmaniasis is a zoonosis in which the dog appears as the main source of infection in urban areas. Its diagnosis is complex and the cytopathological exam is a fast and cheap alternative to parasite direct visualization and its sensitivity can be increased by immunocytochemistry, though with a higher cost. The accuracy of such methods is dependent on the microscopist's experience and therefore, this study evaluated the reliability of such techniques between two observers, from bone marrow aspirates of 50 dogs from an endemic area for the disease. The parasitological culture in Novy-MacNeal-Nicolle medium was used as the reference standard. Among the main findings, the sensitivities obtained by observers I and II were respectively 62.5% and 37.5%, while specificities were 81.1% and 100%. On immunocytochemistry evaluation, the sensitivity was 0% for both evaluators and the specificity 97.3% and 100%. The agreement between evaluators was weak (κ = 0.167) for the cytopathological test and it could not be evaluated for immunocytochemistry, for which there was no detection by the evaluator II. The agreements among the diagnostic methods and the standard reference for the observer I were reasonable (κ = 0.364) for cytopathological examination and bad (κ = -0.041) for immunocytochemistry. For observer II, such agreement could be assessed only for the cytopathological test, being moderate (κ = 0.497). The results point to the possible expertise difference between evaluators, with the evaluator II demonstrating greater experience when interpreting the citopathological test. Although there was the expected sensitivity increase with immunocytochemistry, the technique used in this study was not effective for the diagnosis of infection, regardless of the evaluator.(AU)

Cell-block Immunohistochemistry of Bone Marrow Aspirates: a Novel Tool to Improve the Diagnosis of Leishmania Infection in Dogs.

Parasitological methods are the most specific procedures used for the diagnosis of Leishmania spp. infection, but their limited sensitivity poses a disadvantage and prompts the need for alternatives. The choice of site for sample collection influences diagnostic sensitivity. The combination of an accurate diagnostic method and a technique that allows large-scale field studies is highly desirable to enhance the investigation of Leishmania spp. infection in dogs, especially in endemic regions. The bone marrow is a good target for the detection of Leishmania spp. in dogs. In this context, bone marrow aspiration is rapid and less invasive compared with biopsy procedures, and also enables cell block processing, paraffin wax embedding and the sectioning of samples for further histological and immunohistochemical analyses. The aim of this study was to describe for the first time parasitological methods (immunohistochemistry [IHC] and histopathology) using the cell block technique with bone marrow aspirates for the diagnosis of Leishmania spp. infection in dogs. Bone marrow aspiration was performed in 45 dogs from an area endemic for visceral leishmaniosis for parasitological culture and the cell block technique (histopathology and IHC). Fourteen (31.1%) dogs tested positive for Leishmania spp. by IHC, six (13.3%) by parasitological culture and four (8.9%) by histopathology. Cell block IHC was a useful tool for the diagnosis of canine visceral leishmaniosis. Further studies should be conducted to validate this method for routine epidemiological screening.

The role of dorsomedial hypotalamus ionotropic glutamate receptors in the hypertensive and tachycardic responses evoked by Tityustoxin intracerebroventricular injection.

The scorpion envenoming syndrome is an important worldwide public health problem due to its high incidence and potential severity of symptoms. Some studies address the high sensitivity of the central nervous system to this toxin action. It is known that cardiorespiratory manifestations involve the activation of the autonomic nervous system. However, the origin of this modulation remains unclear. Considering the important participation of the dorsomedial hypotalamus (DMH) in the cardiovascular responses during emergencial situations, the aim of this work is to investigate the involvement of the DMH on cardiovascular responses induced by intracerebroventricular (icv) injection of Tityustoxin (TsTX, a α-type toxin extracted from the Tityus serrulatus scorpion venom). Urethane-anaesthetized male Wistar rats (n=30) were treated with PBS, muscimol or ionotropic glutamate receptor antagonists, bilaterally in DMH and later, with an icv injection of TsTX, or treated only with PBS in both regions. TsTX evoked a marked increase in mean arterial pressure and heart rate in all control rats. Interestingly, injection of muscimol, a GABAA receptor agonist, did not change the pressor and tachycardic responses evoked by TsTX. Remarkably, the injection ionotropic glutamate receptors antagonists in DMH abolished the pressor and the tachycardic response evoked by TsTX. Our data suggest that the central circuit recruited by TsTX, whose activation results in an array of physiological and behavioral alterations, depend on the activation of DMH ionotropic glutamate receptors. Moreover, our data provide new insights on the central mechanisms involved in the development of symptoms in the severe scorpion envenomation syndrome.

Amygdalar neuronal activity mediates the cardiovascular responses evoked from the dorsolateral periaqueductal gray in conscious rats.

There is ample evidence that both lateral/dorsolateral periaqueductal gray (l/dlPAG) and basolateral amygdala (BLA) are essential for the regulation of the autonomic responses evoked during innate reactions to threatening stimuli. However, it is not well established to what extent the BLA regulates the upstream functional connection from the l/dlPAG. Here we evaluated the role of the BLA and its glutamatergic receptors in the cardiovascular responses induced by l/dlPAG stimulation in rats. We examined the influence of acute inhibition of the BLA, unilaterally, by injecting muscimol on the cardiovascular responses evoked by the injection of N-methyl D-aspartate (NMDA) into the l/dlPAG. We also evaluated the role of BLA ionotropic glutamate receptors in these responses by injecting antagonists of NMDA and AMPA/kainate receptor subtypes into the BLA. Our results show that the microinjection of NMDA in the BLA increased the mean arterial pressure (MAP) and heart rate (HR). Injection of NMDA into the l/dlPAG caused similar increases in these variables, which was prevented by the prior injection of muscimol, a GABAA agonist, into the BLA. Moreover, injection of glutamatergic antagonists (2-amino-5-phosphonopentanoate (AP5) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)) into the BLA reduced the increase in MAP and HR induced by l/dlPAG activation. Finally, the inhibition of the central amygdala neurons failed to reduce the cardiovascular changes induced by l/dlPAG activation. These results indicate that physiological responses elicited by l/dlPAG activation require the neuronal activity in the BLA. This ascending excitatory pathway from the l/dlPAG to the BLA might ensure the expression of the autonomic component of the defense reaction.

Sensitivity and specificity of serological tests, histopathology and immunohistochemistry for detection of Toxoplasma gondii infection in domestic chickens.

Since free-range chickens are important for the epidemiology of toxoplasmosis, this study evaluated the sensitivity and specificity of different laboratory techniques for the diagnosis of Toxoplasma gondii in these animals. Serum samples from 135 adult domestic chickens were tested for anti-T. gondii antibodies by the indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and indirect hemagglutination test (IHAT). Tissue samples from all animals were analyzed by histopathology, immunohistochemistry and mouse bioassay (gold standard). Fifty-four chickens were positive for T. gondii in the bioassay. The sensitivity and specificity of the different tests were, respectively, 85% and 56% for ELISA; 80% and 52% for IFAT; 76% and 68% for MAT; 61% and 80% for IHAT; 7% and 98% for immunohistochemistry, and 6% and 98% for histopathology. The MAT was the most effective method for the diagnosis of T. gondii infection in chickens, followed by ELISA. Histopathology and immunohistochemistry are useful tools for the diagnosis of T. gondii infection in chickens due to their specificity.

Blunted GABA-mediated inhibition within the dorsomedial hypothalamus potentiates the cardiovascular response to emotional stress in rats fed a high-fat diet.

Rats fed a high-fat diet (HFD) present an exaggerated endocrine response to stress conditions, which, like obesity, show a high correlation with cardiovascular diseases. Meanwhile the GABAergic neurotransmission within the dorsomedial hypothalamus (DMH) is involved in the regulation of the physiological responses during emotional stress. Here we evaluated the influence of obesity, induced by a HFD, on the cardiovascular responses induced by air jet stress in rats, and the role of the GABAergic tonus within the DMH in these changes. Our results showed that consumption of a HFD (45% w/w fat) for 9 weeks induced obesity and increases in baseline mean arterial pressure (MAP) and heart rate (HR). Moreover, obesity potentiated stress responsiveness, evidenced by the greater changes in MAP and HR induced by stress in obese rats. The injection of muscimol into the DMH reduced the maximal increases in HR and MAP induced by stress in both groups; however, the reduction in the maximal increases in MAP in the HFD group was less pronounced. Moreover, the injection of muscimol into the DMH of obese rats was less effective in reducing the stress-induced tachycardia, since the HR attained the same levels at the end of the stress paradigm as after the vehicle injection. Injection of bicuculline into DMH induced increases in MAP and HR in both groups. Nevertheless, obesity shortened the tachycardic response to bicuculline injection. These data show that obesity potentiates the cardiovascular response to stress in rats due to an inefficient GABAA-mediated inhibition within the DMH.

An anatomopathological study of hepatic coccidiosis (Calyptospora sp. ) in the Acará-pixuna, Aequidens plagiozonatus Kullander, 1984 from the Brazilian state of Pará / Estudo anatomopatológico de coccidiose hepática (Calyptospora sp. ) em Acará-pixuna, Aequidens plagiozonatus Kullander, 1984, no Brasil, estado do Pará

The present study focuses on the anatomopathological alterations provoked by parasitism by Calyptospora sp. in 40 specimens of Aequidens plagiozonatus collected in Pará, Brazil. Examinations of the fresh material by compression of the hepatopancreas and histological sections showed immature forms and oocysts characteristic of the genus Calyptospora, in addition to a large quantity of melanomacrophagic centers spread throughout the organ. No significant inflammation of the hepatic tissue was observed. The melanomacrophagic centers and the compression of the hepatocytes are part of the response of the host to the parasite. This study represents the first record of parasitism by Calyptospora in A. plagiozonatus.

Descreveram-se as alterações anatomopatológicas provocadas pelo parasitismo por Calyptospora sp. em 40 espécimes de Aequidens plagiozonatus, provenientes do município de Peixe-boi, Pará, Brasil. Foram encontradas formas imaturas e oocistos característicos do gênero Calyptospora, nos exames frescos por compressão e cortes histológicos, além de um grande número de centros melanomacrofágicos dispersos por todo o órgão. Digna de nota foi a ausência de inflamação significativa no tecido hepático. Centros melanomacrofágicos e compressão dos hepatócitos estão envolvidos na resposta do hospedeiro ao parasito. Este é o primeiro registro de ocorrência de parasitismo por Calyptospora sp. na espécie estudada.

Gastric lesions in free-ranging black caimans (Melanosuchus niger) associated with Brevimulticaecum species.

The stomachs of 100 free-ranging black caimans (Melanosuchus niger Spix, 1825) from the Mamirauá Sustainable Development Reserve, Amazonas state, Brazil, were examined for parasitism and pathologic lesions. All animals were harvested for human consumption. Ascaridoid nematodes were found in 67 caimans and were identified as Brevimulticaecum sp. These parasites were associated with focally extensive, chronic gastric ulcers and formation of localized intramural granulomas containing nematodes. All caiman were in good nutritional condition, which suggests that effects of gastric nematodiasis on the crocodilian hosts were minimal at the time of slaughter.

Inactivation of neuronal function in the amygdaloid region reduces tail artery blood flow alerting responses in conscious rats.

Few studies have investigated whether neuronal function in the amygdaloid complex is necessary for the occurrence of the cardiovascular response to natural (unconditioned) environmental threats. In the present investigation in conscious unrestrained Sprague-Dawley rats we inactivated neuronal function in the amygdaloid complex acutely (bilateral muscimol injections) or chronically (unilateral or bilateral ibotenic acid injections) and measured the effect on sudden falls in tail artery blood flow elicited by non-noxious salient stimuli (sympathetic cutaneous vasomotor alerting responses, SCVARs). After acute bilateral injection of vehicle (200nl Ringer's solution) the SCVAR index was 81 ± 2%, indicating that tail blood flow was reduced by 81% in response to the salient stimuli. After acute bilateral injection of muscimol (1 nmol in 200 nl of Ringer's solution) into the amygdaloid complex the SCVAR index was 49 ± 5%, indicating that tail blood flow was reduced by 49% in response to the salient stimuli (p<0.01 versus vehicle, n=7 rats for vehicle and 6 for muscimol). One week after unilateral ibotenic acid lesions, the SCVAR index was 68 ± 3%, significantly less than 90 ± 1%, the corresponding value after unilateral injection of vehicle (p<0.01, n=6 rats in each group). After bilateral ibotenic acid lesions the SCVAR index was 52 ± 4%, significantly less than 93 ± 1%, the corresponding value after bilateral injection of vehicle (p<0.001, n=6 rats in each group). Ibotenic acid caused extensive neuronal destruction of the whole amygdaloid complex, as well as lateral temporal lobe structures including the piriform cortex. Our results demonstrate that the amygdaloid complex plays an important role in mediating the tail artery vasoconstriction that occurs in rats in response to the animal's perception of a salient stimulus, redirecting blood to areas of the body with more immediate metabolic requirements.

Helmintos oxiuridae parasitos de Iguana iguana (Squamata, Lacertilia, Iguanidae) procedentes do Brasil / Oxiuridae helminths parasites of Iguana iguana (Squamata, Lacertilia, Iguanidae) in Brazil

The results of a study on nematode fauna occurring in wild iguanas (Iguana iguana) from Brazilian Northeast (Alagoas and Maranhão) and Central-west (Goiás and Mato Grosso) areas were presented. Six adult iguanas, three males and three females, were necropsied and the digestive system removed to examination. All the iguana specimens were heavily parasitized. The helminths diagnosed were: Ozolaimus cirratus in the cecum and colon of five iguanas; Ozolaimus megatyphlon in cecum, colon and rectum of three iguanas; and Alaeuris vogelsangi in the small intestine, cecum, colon and rectum of five animals. Two larvae of Ozolaimus sp. were recovered from the pyloric region of the stomach of one iguana. The three diagnosed species of nematodes were reported for the first time in the Brazilian Central-West region.

The dorsomedial hypothalamus and the central pathways involved in the cardiovascular response to emotional stress.

Psychological stress elicits increases in sympathetic activity accompanied by a marked cardiovascular response. Revealing the relevant central mechanisms involved in this phenomenon could contribute significantly to our understanding of the pathogenesis of stress-related cardiovascular diseases, and the key to this understanding is the identification of the nuclei, pathways and neurotransmitters involved in the organization of the cardiovascular response to stress. The present review will focus specifically on the dorsomedial hypothalamus, a brain region now known to play a primary role in the synaptic integration underlying the cardiovascular response to emotional stress.

Neoplasias espontâneas em camundongos de um centro de criação de animais de laboratório / Spontaneous neoplasms in mice from a center of a laboratory animal breeding

Verificaram-se a prevalência e as características anatomopatológicas de neoplasias espontâneas encontradas em camundongos, provenientes de biotério. Foram necropsiados 9.219 camundongos pertencentes a 13 linhagens, entre agosto de 2002 e janeiro de 2007, para monitoramento sanitário. Amostras de tecidos foram colhidas, fixadas em formol tamponado a 10 por cento e processadas pelas técnicas habituais para inclusão em parafina. Foram realizados 84 diagnósticos de neoplasmas, sendo acometidos 82 camundongos (0,9 por cento). As principais neoplasias diagnosticadas com as respectivas ocorrências foram: carcinoma mamário, 27,4 por cento; linfoma, 19,0 por cento; adenocarcinoma papilífero pulmonar primário, 17,9 por cento; carcinoma epidermoide, 8,3 por cento; osteossarcoma osteoblástico, 4,8 por cento; e outros com menor porcentagem de ocorrência. Houve predomínio de tumores malignos, sendo mais frequentes os carcinomas mamários. A linhagem BALB/c An foi a que apresentou a maior variedade de tipos de neoplasias, seguida das linhagens outbred Swiss Webster e NIH. Fibrossarcoma em camundongos C57BL/10 ScSn-Dmd mdx/J e carcinoma mamário na linhagem NOD foram relatados pela primeira vez.

The prevalence and the pathologic features of spontaneous neoplasms found in mice from a breeding colony were verified. Nine thousand two hundred and nineteen mice belonging to 13 strains were submitted to necropsy from August 2002 to January 2007 for health monitoring. Tissue samples were collected, fixed in 10 percent buffered formalin, and processed by the usual techniques for inclusion in paraffin. Eighty-four neoplasms were diagnosed and 82 mice had tumors (0.9 percent). The main neoplasms were diagnosed with the following occurrences: mammary carcinoma, 27.4 percent; lymphoma, 19.0 percent; primary papillary pulmonary adenocarcinoma, 17.9 percent; squamous carcinoma, 8.3 percent; osteoblastic osteosarcoma, 4.8 percent; and others with a lower percentage of occurrence. The malignant tumors predominated and the most common tumor was the mammary carcinoma. The wider variety of neoplasm types was found in the BALB/c An strain, followed by the outbred strains Swiss Webster and NIH. The fibrossarcoma in C57BL/10 ScSn-Dmd mdx/J mice and mammary carcinoma in NOD mice were reported for the first time.

Comparative histopathological study of sporotrichosis and American tegumentary leishmaniasis in dogs from Rio de Janeiro.

Pyogranulomatous lesions from 80 dogs with sporotrichosis and 26 dogs with American tegumentary leishmaniasis (ATL) were compared microscopically in order to identify features that would support the diagnostic suspicion and direct the subsequent search for the aetiological agent of either infection. Odds ratios and their respective 95% confidence intervals were calculated in order to evaluate the impact of the microscopical findings on the diagnosis of either disease. Lesions with well-formed granulomata were 14 times more likely to be due to sporotrichosis than ATL. Marked neutrophil infiltration into granulomata was 12.26 times more likely to be associated with sporotrichosis when compared with lesions having mild neutrophilic infiltration. Absence of lymphocytes and macrophages in the peripheral infiltrate was associated with a 9.71 and 4.93 higher chance, respectively, of being sporotrichosis rather than ATL compared with lesions where these cells were present. Lesions with a perivascular, perifollicular and interstitial peripheral inflammatory infiltrate were 5.48 times more likely to be due to sporotrichosis than ATL when compared with lesions with a diffuse peripheral infiltrate. Histopathological analysis may therefore contribute to the diagnosis of sporotrichosis or ATL skin lesions in dogs since this method permits the identification of features that direct the diagnostic suspicion, thus facilitating the search for the aetiological agent in histological sections, permitting the precise request of subsequent tests and thereby reducing costs and time taken to achieve a definitive diagnosis and the initiation of appropriate therapy.

Efficacy of an indirect immunofluorescence test in the diagnosis of canine leishmaniosis.

Of 146 dogs from a visceral leishmaniosis-endemic area that tested seronegative by indirect immunofluorescence (IIF) on blood samples collected on filter paper (IIFp), 51 (34.9%) and 10 (6.8%) tested positive by IIF on serum samples (IIFs) and enzyme immunoassay, respectively. Three samples (2.0%) tested positive by PCR. Leishmania chagasi was isolated from the skin of five (3.4%) dogs. Amastigote forms were identified in two of these five animals following histopathological and immunohistochemical examination. The findings highlight that detection methods such as IIFp can permit dogs infected with L. chagasi to remain undetected in endemic areas with attendant consequences for the epidemiology of infection both in the canine and human populations.

Brown adipose tissue thermogenesis heats brain and body as part of the brain-coordinated ultradian basic rest-activity cycle.

Brown adipose tissue (BAT), body and brain temperatures, as well as behavioral activity, arterial pressure and heart rate, increase episodically during the waking (dark) phase of the circadian cycle in rats. Phase-linking of combinations of these ultradian (<24 h) events has previously been noted, but no synthesis of their overall interrelationships has emerged. We hypothesized that they are coordinated by brain central command, and that BAT thermogenesis, itself controlled by the brain, contributes to increases in brain and body temperature. We used chronically implanted instruments to measure combinations of bat, brain and body temperatures, behavioral activity, tail artery blood flow, and arterial pressure and heart rate, in conscious freely moving Sprague-Dawley rats during the 12-h dark active period. Ambient temperature was kept constant for any particular 24-h day, varying between 22 and 27 degrees C on different days. Increases in BAT temperature (> or = 0.5 degrees C) occurred in an irregular episodic manner every 94+/-43 min (mean+/-SD). Varying the temperature over a wider range (18-30 degrees C) on different days did not change the periodicity, and neither body nor brain temperature fell before BAT temperature episodic increases. These increases are thus unlikely to reflect thermoregulatory homeostasis. Episodic BAT thermogenesis still occurred in food-deprived rats. Behavioral activity, arterial pressure (18+/-5 mmHg every 98+/-49 min) and heart rate (86+/-31 beats/min) increased approximately 3 min before each increase in BAT temperature. Increases in BAT temperature (1.1+/-0.4 degrees C) were larger than corresponding increases in brain (0.8+/-0.4 degrees C) and body (0.6+/-0.3 degrees C) temperature and the BAT episodes commenced 2-3 min before body and brain episodes, suggesting that BAT thermogenesis warms body and brain. Hippocampal 5-8 Hz theta rhythm, indicating active engagement with the environment, increased before the behavioral and autonomic events, suggesting coordination by brain central command as part of the 1-2 h ultradian basic rest-activity cycle (BRAC) proposed by Kleitman.