Epidermal growth factor receptors, testosterone levels and parotid gland changes in rats infected with Trypanosoma cruzi

It has been demonstrated that parotid glands of rats infected with Trypanosoma cruzi present severe histological alterations; changes include reduction in density and volume of the acini and duct systems and an increase in connective tissue. We evaluated the association between morphological changes in parotid glands, circulating testosterone levels and epidermal growth factor receptor (EGF-R) expression in experimental Chagas disease in rats. Animals at 18 days of infection (acute phase) showed a significant decrease in body weight, serum testosterone levels and EGF-R expression in the parotid gland compared with a control group. Since decreases in body weight could lead to a reduction in circulating testosterone concentration, we believe that the reduction in EGF-R expression in parotid glands of infected rats is due to alterations in testosterone levels and atrophy of parotid glands is caused by changes in EGF-R expression. Additionally, at 50 days (chronic phase) of infection parotid glands showed a normal histological aspect likely due to the normalization of the body weight. These findings suggest that the testosterone-EGF-R axis is involved in the histological changes

Xenodiagnóstico artificial "post-mortem" em chagásicos crônicos

A fim de obter metodologias que permitam estabelecer, com segurança, o diagnóstico "post-mortem " da infecção chagásica, adaptou-se o xenodiagnóstico artificial a necropsiados com diferentes tempos de óbito. O testefoi positivo em três (30%) de dez chagásicos autopsiados. O tempo decorrido entre o êxito letal e o início do repasto pelos triatomineos destes chagásicos foi de duas horas, duas horas e quinze minutos e sete horas, respectivamente. Discutem-se os fatores que podem explicara sobrevivência do Trypanosoma cruzi no hospedeiro morto bem como as aplicações práticas do achado

Plasma total homocysteine (tHcy) levels and methylenetetrahydrofolate reductase gene polymorphism in patients with type 2 diabetes mellitus

Background: thrombotic episodes account for approximately 80% of deaths in type 2 diabetic patients. Hyperhomocysteinaemia is a well recognized independent risk factor for atherosclerosis and thromboembolism. Increased homocysteine levels may occur due to a number of factors including inherited gene polymorphism of methylenetetrahydrofolate reductase (MTHFR) C677T. Here, we evaluate plas- ma total homocysteine (tHcy) levels and frequency of the MTHFR C677T gene polymorphism in asymptomatic healthy volunteers and type 2 diabetic patients with hypertension but without nephropathy. We have also investigated the relationship between tHcy levels and the presence of MTHFR C677T gene polymorphism. Methods: plasma tHcy levels and MTHFR C677T genotype were investigated in a total of 53 subjects. These included asymptomatic healthy volunteers (n = 16), patients with type 2 diabetes (n = 7), subjects with hypertension (n = 12) and patients with both type 2 diabetes and hypertension (n = 18). Renal function, serum lipids and other metabolites were also assessed. Results: there was no significant difference in tHcy levels between the groups studied. The frequency of MTHFR C677T gene polymorphism observed was similar to that obtained for the general Brazilian population. In patients with type 2 diabetes and hypertension but without impaired renal function, we observed no meaningful correlation between increased tHcy levels and the presence of MTHFR C677T gene polymorphism. Conclusions: type 2 diabetics who are homozygous or heterozygous for the MTHFR C677T gene polymorphism showed normal tHcy levels. Our results further suggest that diabetes without an associated adverse risk profile is not an independent correlate of increased tHcy level