Behaviour of albino and melanic variants of Biomphalaria glabrata Say, 1818 (Mollusca: Planorbidae) following infection by Schistosoma mansoni Sambon, 1907

The behaviour of the albino and melanic variants of Biomphalaria glabrata of Belo Horizonte (MG. Brazil) was studied comparatively, in terms of their respective susceptibilities to infection by Schistosoma mansoni of the same origin, through observation of the elimination of cercariae for a three-month period and the calculation of mortality and infection rates, in control and in infected snails. The number of amoebocytes, granulocytes and hyalinocytes in the circulating hemolymph during different periods of infection was analyzed. The evolution of the infection in the tissues was observed by means of histological cross-sections. The melanic variant showed greater susceptibility to infection and a higher mortality rate. The albino variant showed a higher number of circulating amoebocytes, both granulocytes and hyalinocytes. A higher number of degenerated sporocysts were seen in the histological cross-sections of the albino variant. The results suggest that the melanic variant of B. glabrata was more susceptible to infection by S. mansoni than was the albino variant.

Cumulative doses of radioiodine in the treatment of differentiated thyroid carcinoma: knowing when to stop

OBJECTIVE: Evaluate the efficacy of cumulative doses (CDs) of 131I-iodide therapy (RIT) in differentiated thyroid cancer (DTC). SUBJECTS AND METHODS: The probability of progressive disease according to CDs was evaluated in patients < 45 years old and > 45 years old and correlated to tumor-node-metastasis (TNM), thyroglobulin values, histological types and variants, age, and zduration of the disease. RESULTS: At the end of a follow-up period of 69 ± 56 months, 85 out of 150 DTC patients submitted to fixed doses RIT had no evidence of disease, 47 had stable disease and 18 had progressive disease. Higher CDs were used in the more aggressive variants (p < 0.0001), higher TNM stages (p < 0.0001), and follicular carcinomas (p = 0.0034). Probability of disease progression was higher with CDs > 600 mCi in patients > 45 years old and with CDs > 800 mCi in patients < 45 years. CONCLUSION: Although some patients may still respond to high CDs, the impact of further RIT should be carefully evaluated and other treatment strategies may be warranted.