Disseminated transmissible venereal tumour associated with Leishmaniasis in a dog.

This report addresses an atypical transmissible venereal tumour in an 8-year-old bitch that was pluriparous and seropositive for leishmaniasis. There were ascites and a serosanguineous discharge from the vulva, but no lesions on the external genital mucosa. An aspirate of the peritoneal fluid showed mononuclear round cells characteristic of transmissible venereal tumour (TVT). Exploratory laparotomy revealed light red, granulomatous structures in the peritoneum, omentum, spleen, liver and uterine horns. Cytological and histopathological tests confirmed the diagnosis of intra-abdominal TVT. Dissemination of the TVT to several organs inside the abdominal cavity probably resulted from immunosuppression caused by leishmaniasis, which favoured the presence and aggressiveness of TVT.

Evaluation of antinociceptive and antiinflammatory activities of the essential oil (EO) of Ocimum micranthum Willd. from Northeastern Brazil.

The EO of Ocimum micranthum was studied for a possible analgesic effect on the acetic acid induced writhing and formalin test in mice and antioedema activities on the carrageenan and dextran induced paw oedema in rats. The EO demonstrated antinociceptive effects, and pretreatment with naloxone did not reverse the antinociception, indicating that the opioid system is not involved. On the other hand, pretreatment with L-arginine (L-arg) reversed the antinociception, suggesting involvement of the nitric oxide (NO) system. The EO did not present an antioedematogenic effect in the carrageenan and dextran models.

Effects of dopaminergic and cholinergic interactions on rat behavior.

The present work studied the effects of dopaminergic and muscarinic receptor agonists and antagonists on rat locomotor activity and catalepsy. Results showed that carbachol at the highest dose used (10 mg/kg, p.o.) decreased and pimozide at the dose used abolished locomotor activity. Atropine at a low dose (1 mg/kg, p.o.) increased and at a high dose decreased this parameter. Mazindol at a high dose also increased locomotor activity. A significant and dose-dependent increase in the time on the bar was observed in animals treated with carbachol or pimozide as compared to controls. The increase observed with pimozide was greater than 60 s. Effects of carbachol on locomotor activity were observed already after the first drug exposure, but the increased time on bar produced by this drug in the test of catalepsy was observed only after repeated exposure (7th day). The effect of the highest dose (10 mg/kg, p.o.) of atropine (decreased activity) as related to the lowest one was evident at the 7th day, but the increased locomotor activity seen at the low dose was detected already at the first day. There was a predominance of the effect of pimozide on the open field as well as on catalepsy after its association with each one of the three doses of carbachol. The association of atropine and mazindol did not seem to alter locomotor activity and catalepsy as related to each drug alone. Our results indicate that interactions between dopaminergic and cholinergic systems play an important role on behavior and motor functions.

Early withdrawal from repeated cocaine administration upregulates muscarinic and dopaminergic D2-like receptors in rat neostriatum.

The present results show an increase in locomotor activity 24 h following repeated cocaine administration only with the higher dose (10 mg/kg, i.p., daily for 1 week) compared to controls (administered with saline). Binding assays were done and the ligands used were [3H]N-methylscopolamine ([3H]-NMS), [3H]-SCH 23390, and [3H]-spiroperidol to determine muscarinic (M1- and M2-like), D1 and D2 receptors, respectively. Scatchard analyses revealed alterations in Bmax not only for muscarinic, but also for D2-like receptors that were significantly increased. On the other hand, no alterations were detected on D1-like receptors densities and dissociation constant values. However, the Kd value was significantly increased for D2 receptors. The changes in muscarinic receptors were observed predominantly on M2-like, which presented an increase of 84% with the 10 mg/kg, i.p., dose only. On D2-like receptors, increases of 63 and 54% were demonstrated with the doses of 5 and 10 mg/kg, i.p.. The preferential effects of cocaine on muscarinic and D2-like receptors were also demonstrated in vitro where decreases in [3H]-NMS and [3H]-spiroperidol binding were observed. The results indicate that the effects of cocaine on muscarinic and dopaminergic postsynaptic receptors are functions of dose, duration of treatment, and time of drug withdrawal.

Distribution of heparin and other sulfated glycosaminoglycans in vertebrates.

1. A comparative study on the distribution of sulfated glycosaminoglycans in several tissues of six specimens of different vertebrate classes is reported. 2. Each tissue has a characteristic composition differing from each other regarding the relative amount, type and molecular size of chondroitin 4.6-sulfate, dermatan sulfate and heparan sulfate. 3. The same tissue from different vertebrates has, in general, the same types of sulfated glycosaminoglycans, but with different molecular weights. 4. Exception to this rule was observed for the distribution of heparin which was present only in a few tissues of the 6 vertebrates studied. 5. The possible involvement of the sulfated glycosaminoglycans in cell recognition and/or adhesiveness is discussed in view of this characteristic distribution.