Pressure-induced left ventricular hypertrophy in canine model of aortic stenosis using nylon tie

The aim of this study was to develop an experimentally-induced canine model of left ventricular hypertrophy through banding of the ascending aorta using nylon ties. Seven clinically normal dogs free of cardiovascular disease were used. Nylon tie was used in banding the mid-ascending aorta. Clinical, radiographic and echocardiographic evaluations were done at 1.5, 3 and 6 months. Dogs were euthanized at 6 months for post mortem and histopathological evaluation. Clinically, dogs did not exhibit any signs of cardiovascular disease at 1.5 or 3 months, while at 6 months two dogs (28.6 %) exhibited mild weight loss, exercise intolerance and heart murmurs. Radiographic evaluation revealed significant increase in cardiac size only at 6 months based on measurement of the cardiothoracic area evaluation. Echocardiography revealed increased left ventricular wall thickness starting from 1.5 month, although this increase was statistically significant at 3 and 6 months (p > 0.05). Left ventricular hypertrophy was confirmed by post mortem examination. Histopathological sections of left ventricle in all dogs demonstrated myocyte hypertrophy and interstitial fibrosis. This model simulates the naturally occurring ventricular hypertrophy using a rapid and economic technique. Such models are required to understand pathogenesis of heart disease and to develop effective treatment strategy.

Efficacy of some drugs and pathological studies on toxoplasma gondii infection in mice

The present investigation was conducted to study the effect of infection with Toxoplasma gondii and the efficacy of azithromycin and garlic tablets on treatment of acute murine toxoplasmosis in addition to study the histopathojogical changes due to infection. For this purpose, sixty Albino mice were used as experimental animals that equally divided into 6 groups. Estimation of survival rate, pathological studies, bioassay trial and immunofluorescent study were performed for each group of mice. High efficacy of azithromycin at a dose of 250 mg/kg/day on infected mice was shown, that increased survival rate [90% at the 7th day PI] and decreased the histopathological changes when compared with control groups. Garlic tablets at a dose of 500 mg/kg/day showed fewer efficacies in infected mice, survival rate [40% at the 6th and 7th day P.1] which was lesser than those groups treated with azithromycin Pathologically, group treated with azithromycin showed improvement in histological pictures compared with group treated with garlic. To identify the efficacy of the drug, at the end of the experiment subinoculation of healthy mice by visceral and brain suspensions from surviving mice treated with azithromycin or garlic was performed as compared with subinoculation of suspension of brain and visceral of infected non treated mice inoculated into healthy mice, that showed death of these mice after three days post-infection [survival rate 0%]. It was concluded that azithromycin has a significant effect in treatment of murine model toxoplasmosis, but it did not eradicate the parasite completely as few cysts remained in the brain, while garlic tablets had a limited effect for treating toxoplasmosis