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In the present work we established a relationship between some physicochemical properties of two different batches of Prussian blue (PB) and their in vivo efficacy as an antidote against thallium poisoning. The physicochemical properties studied were crystallite size and thallium-adsorbing capacity. One of the batches was synthesized and the other was obtained from commercial sources. The synthesized PB batch with the smallest crystallite size had both the highest adsorption capacity and antidotal efficacy. Synthesized PB protected 100% of the animals against one LD50 thallium dose, whereas the commercial PB batch protected only 80%. Thallium content in blood and tissues (liver, kidney, brain) was also analysed after antidotal PB treatment in rats previously intoxicated with a sublethal dose of T1+. Animals treated with synthesized PB showed significantly less thallium in blood and tissue contents than those values of commercial PB-treated rats, indicating better antidotal properties of the synthesized PB. According to the present study we suggest an in vivo evaluation of the compound before distribution of the product to toxicological units, if X-ray diffractometric analysis is not available, in order to identify and determine the crystallite size of the compound as it plays an important role in the efficacy of PB.

Amantadine is used in the symptomatic treatment of Parkinson's disease to improve the akinesia and rigidity associated with this neurodegenerative disorder. Amantadine acts on the synthesis and release of dopamine (DA). In order to further characterize its mechanism of action, the drug was administered to MPTP-treated mice which were used as a model of the neurochemical deficits associated with Parkinson's disease. The D A turnover in corpus striatum was evaluated. Adult male Swiss albino mice were injected ip with 12.5 mg/kg (82.6 p,mol/kg) or 25 mg/kg (165 kmol/kg) of amantadine and 30 min later with MPTP (30 mg/kg, 143 p,mol/kg). Both the arnantadine and MPTP treatments were repeated for 3 consecutive days. Groups of mice were treated with amantadine or MPTP alone. Seven days after the last injection o f drugs, the striatal content of D A and homovanillic acid (HVA) were measured b y HPLC-EC analysis. Additional groups of mice were treated with 3 consecutive daily doses of MPTP (30 mg/kg, 143 pmol/kg) and 7 days after the last administration received a single dose of amantadine at 25 mg/kg (165 p,mol/kg). Turnover rate was measured by HVA content determination. The results indicate that amantadine induced a significantly increased striatal DA turnover rate (34%) in MPTP-treated animals as compared with those animals treated with only MPTP. o 1993 WiIey-Liss, Inc.

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This study investigated the effects of chronic administration of thalidomide on three different neoplasms of ectodermic origin in rodents: 1) chemically induced tumors of the nervous system of rats by transplacental exposure to ethylnitrosourea; 2) transplanted RPMI-1846 melanoma in hamsters and 3) transplanted C6 glioblastoma in rats. No effects were seen on thalidomide-treated rats on the frequency- and time of tumor development induced by ethylnitrosourea. In contrast, a reduction in tumoral growth and mitotic-index was obtained in animals treated with thalidomide in transplanted tumors, melanoma and glioblastoma, when compared with controls (P < 0.001 and 0.025, respectively). These results suggest that, although thalidomide is not a cytotoxic drug for neoplastic cells, it might partially inhibit the tumoral growth through any of its pharmacological actions; by blockage of cell-surface adhesion receptors induction of DNA oxidation, or inhibition of angiogenesis. Further investigations on the use of thalidomide perhaps associated to cytotoxic drugs, for treatment of ectodermic neoplasms seem guaranteed.

A1 1 bentonites samp e s including those used a s reference were c h a r a c t e r i z e d by x-ray d f f r a c t i o n minerological s t u d y , whole chernial a n a l y s i s ( t o t a l o x i d e s ) , ion exchange c a p a c i t y and physical-chemical p r o p e r t i e s t e s t s . The x-ray d i f f r a c t i o n a n a l y s i s reveal only s l i g h t d i f f e r e n c e s among mexican bentoni tes raw m a t e r i a l . E i t h e r Mexican bentonite or t h e reference material show very s i m i l a r impurity c o n t e n t . Chemical a n a l y s i s o f bentoni t e s show wide v a r i a b i l i t y i n oxide content b u t r e s u l t s a r e i n c l o s e accordance with those reported i n t h e 2249 ('opyriglrt 0 1'1x7 by Marcel Lkkker, Inc. Drug Dev Ind Pharm Downloaded from informahealthcare.com by Washington University Library on 01/05/15 For personal use only.