Blackfoot disease (BFD) is an endemic peripheral vascular disorder resulting in gangrene of the lower extremities, especially the feet, among residents in a limited area on the southwest coast of Taiwan. In the present study, the concentrations of zinc, cadmium, lead, and copper in urine of BFD patients with matched normal controls are investigated by differential pulse anodic stripping voltammetry (DPASV) on a hanging mercury drop electrode (HMDE). The analytical results indicate that urinary copper, cadmium, and lead of the BFD patients are significantly higher than those of the controls. In addition, the patients showed a significantly lower concentration of zinc in the urine than the normal controls. The possible connection of these elements with the etiology of the disease is discussed.

In this work, the poly(methacrylic acid-co-N-isopropylacrylamide) thermosensitive composite hollow latex particles was synthesized by a three-step reaction. The first step was to synthesize the poly(methyl methacrylate-co-methacrylic acid) (poly(MMA-MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second step was to polymerize methacrylic acid (MAA), N-isopropylacrylamide (NIPAAm), and N,N 0 -methylenebisacrylamide in the presence of poly(MMA-MAA) latex particles to form the linear poly(methyl methacrylate-co-methacrylic acid)=crosslinking poly(methacrylic acid-co-N-isopropylacrylamide) (poly(MMA-MAA)=poly(MAA-NIPAAm)) core-shell latex particles. In the third step, the core-shell latex particles were heated in the presence of ammonia solution to form the crosslinking poly (MAA-NIPAAm) thermosensitive hollow latex particles. The morphologies of poly(MMA-MAA)=poly(MAA-NIPAAm) coreshell latex particles and poly(MAA-NIPAAm) hollow latex particles were observed. The influences of crosslinking agent and shell composition on the lower critical solution temperature of poly(MMA-MAA)=poly(MAA-NIPAAm) core-shell latex particles and poly(MAA-NIPAAm) hollow latex particles were, respectively, studied. Besides, the poly(MAA-NIPAAm) thermosensitive hollow latex particles were used as carriers to load with the model drug, caffeine. The effect of various variables on the amount of caffeine loading and the efficiency of caffeine release was investigated.

Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Though extensive epidemiological study has implicated that high arsenic content in artesian well water of the endemic area bears some important connection with the disease, the etiology of the disease is still unknown. In this study, attention is paid to multielement determination in order to find out whether the trace elements in hair of Blackfoot disease patients are different from those of the controls. Experimental results indicate that the concentrations of As and Se in hair of patients are significantly higher than those of the controls, but Ca and Zn are significantly lower than those of the controls. The possible connection of these elements with the etiology of the disease is discussed.

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