T and B lymphocytes in the brains of dogs with concomitant seropositivity to three pathogenic protozoans: Leishmania chagasi, Toxoplasma gondii and Neospora caninum.

BACKGROUND: Visceral leishmaniasis is a disease with great variability regarding the clinical manifestations in humans and dogs. Chronically infected dogs may develop neurological disorders, however, there are few reports that characterize the lesions and make clear the pathogenesis of the canine cerebral leishmaniasis. Concomitant with Leishmania chagasi, dogs may be infected by opportunistic pathogens, such as Toxoplasma gondii and Neospora caninum, which may contribute to the occurrence of lesions in the central nervous system. Hence, we aimed to compare the T and B lymphocytes population in the brains of infected dogs with seropositivity to L. chagasi, T. gondii and N. caninum concurrently (n = 24), seropositivity only to L. chagasi (n = 31), and seropositivity to T. gondii and N. caninum (n = 16). Uninfected dogs were used as control (n = 10). RESULTS: Inflammatory lesions, characterised by mononuclear cell accumulation, composed mainly of CD3+ T lymphocytes predominated in several encephalic regions of the dogs from all the three infected groups, with no difference among them (P = 0.0004), whereas CD79α+ B lymphocytes were detected in very small intensity and presented no difference among groups (P = 0.5313). Furthermore, no association among diseases was detected at the serological enquire. CONCLUSIONS: We demonstrate that the peripheral infection by L. chagasi per se can promote the influx of lymphocytes within the nervous milieu as occurs during Toxoplasma and Neospora infections, and the concomitant seropositivity against these pathogens does not exacerbate the inflammatory brain lesions. Therefore, these findings give additional support that the brain should be included in the list of organs affected by visceral leishmaniasis and that even asymptomatic infected dogs may develop brain lesions.

Evaluation of the Perkins handheld applanation tonometer in the measurement of intraocular pressure in dogs and cats.

OBJECTIVE: To evaluate and to validate the accuracy of the Perkins handheld applanation tonometer in the measurement of IOP in dogs and cats. ANIMALS: Twenty eyes from 10 dogs and 10 cats immediately after sacrifice were used for the postmortem study and 20 eyes from 10 clinically normal and anesthetized dogs and cats were used for the in vivo study. Both eyes of 20 conscious dogs and cats were also evaluated. PROCEDURE: Readings of IOP postmortem and in vivo were taken using manometry (measured with a mercury column manometer) and tonometry (measured with a Perkins handheld applanation tonometer). The IOP measurement with Perkins tonometer in anesthetized and conscious dogs and cats was accomplished by instillation of proxymetacaine 0.5% and of 1% fluorescein eye drops. RESULTS: The correlation coefficient (r(2)) between the manometry and the Perkins tonometer were 0.982 (dogs) and 0.988 (cats), and the corresponding linear regression equation were y = 0.0893x + 0.1105 (dogs) and y = 0.0899x + 0.1145 (cats) in the postmortem study. The mean IOP readings with the Perkins tonometer after calibration curve correction were 14.9 +/- 1.6 mmHg (range 12.2-17.2 mmHg) in conscious dogs, and were 15.1 +/- 1.7 mmHg (range 12.1-18.7 mmHg) in conscious cats. CONCLUSION: There was an excellent correlation between the IOP values obtained from direct ocular manometry and the Perkinstonometer in dogs and cats. The Perkins handheld tonometer could be in the future a new alternative for the diagnosis of glaucoma in veterinary ophthalmology.

Uso tópico do amitraz em concentração terapêutica em gatos / Topical use of amitraz in therapeutic concentration in cats

O amitraz é um inseticida do grupo das formamidinas muito utilizado como acaricida e carrapaticida em medicina veterinária. O presente trabalho teve como objetivo analisar as alterações induzidas com o uso do amitraz por via tópica, através de banho, em concentração terapêutica de 0,05 por cento, avaliando-se a freqüência cardíaca, o eletrocardiograma, a pressão arterial sistólica, a freqüência respiratória, a temperatura retal, o diâmetro pupilar e o grau de sedação, além da dosagem da concentração de glicose, insulina e cortisol. As alterações observadas foram diminuição da pressão arterial, hipotermia, vômito, salivação, midríase, grau de sedação leve e aumento no nível de glicose. Alguns animais, individualmente, em alguns momentos, também apresentaram arritmia sinusal. Apesar de ter ocorrido diminuição da freqüência cardíaca e pressão arterial sistólica e aumento no nível de glicose, esses valores estavam dentro da normalidade referida para a espécie felina. O trabalho demonstrou que a utilização do amitraz por via tópica em concentração terapêutica é segura em gatos hígidos e, assim como ocorre em outras espécies, o seu uso deve ser contra-indicado em gatos diabéticos, com problemas cardíacos e hipotérmicos.

Amitraz is an insecticide of the formamidine group very used as acaricide and tickicide in veterinary medicine. The present research was aimed at analyzing the alterations induced by the topical use of amitraz in therapeutic concentration of 0.05 percent. Heart rate, electrocardiogram, systolic blood pressure, respiratory rate, rectal temperature, pupil diameter and degree of sedation, dosage of the glucose, insulin and cortisol concentration were measurements. The alterations were blood pressure decrease, hypothermia, vomit, salivation, mydriasis, light degree of sedation and increase in plasma glucose level. Some animals also presented sinusal arrhthymia. In spite of having occurred decrease of the heart rate and systolic blood pressure and increase in the glucose levels, these values were inside of the normality referred for the feline species. The research demonstrated that the use of the amitraz by topical way in therapeutic concentration is safe in healthy cats, and as well as it happens in other species, itÆs use should be contraindicated in cats with diabetic, heart problems and hypothermia.