Changes of nerve excitability and urinary deltamethrin in sprayers

The nerve excitability of median nerve as well as the urinary deltamethrin and its metabolite dibromovinyl-dimethyl-cyclopropane carboxylic acid (Br2A) were detected in 24 deltamethrin sprayers in an assessment of the exposure and effect of deltamethrin. Twenty-nine male, unexposed referents of the same age range were also selected. The urinary deltamethrin and its metabolite Br2A were detectable by GC and HPLC in the sprayers after exposure. The nerve excitability detected with an electromyograph and pairs of stimuli at variable intervals showed that there was a prolongation of supernormal period in median nerve of the exposed group after a 3-d spraying compared with that before spraying which became more significant 2 d after cessation of exposure. In the mean time, no change of supernormal period in the median nerve of reference group was found at the 3-d interval. Nearly half of the sprayers had a supernormal period prolonged by more than 4 ms after spraying, whereas nearly none of the reference group showed similar changes after repeated examinations. Although there was neither correlation between the nerve excitability changes and the urinary deltamethrin or Br2A excretion, nor was a case of acute deltamethrin poisoning diagnosed, the non invasive technique used for nerve excitability detection in this study seems to be valuable in studying deltamethrin toxicity on human.

The structures of different diastereomers of bicyclo[2.2.1]hept-5-en-2-yl phenyl sulfoxide

Three diastereomers of bicyclo[2.2.1]hept-5-en-2-yl phenyl sulfoxide were prepared by Diels-Alder [4 + 2] cycloadditions between phenyl vinyl sulfoxide and cyclopentadiene. The isomers were separated by column chromatography on silica gel and repeated recrystallizations gave the pure racemates of three of the four possible diastereomers. It proved to be impossible to assign the stereochemistry of the products from low-resolution NMR spectra. The X-ray diffraction studies of the three diastereomers showed the relative configuration at the two chiral centers and these stereochemical assignments were, subsequently, correlated with the two-dimensional NMR spectroscopic results. Compound (I), exo-(2R*,8S*)-bicyclo[2.2.1]hept-5-en-2-yl phenyl sulfoxide [or the exo-(2S*,8R*)-isomer], C13H14OS, Mr = 218.31, orthorhombic, P2(1)2(1)2(1), a = 10.517 (2), b = 10.914 (2), c = 9.642 (3) A, V = 1106.7 A3, Z = 4, Dx = 1.31 g cm-3, Cu K alpha, lambda = 1.54178 A, mu = 22.14 cm-1, F(000) = 464, T = 138 (2) K, R = 0.042 for 1151 data. Compound (II), exo-(2RS,8RS)-bicyclo[2.2.1]hept-5-en-2-yl phenyl sulfoxide, C13H14OS, Mr = 218.31, triclinic, P1, a = 8.775 (4), b = 16.353 (8), c = 7.804 (3) A, alpha = 90.67 (3), beta = 101.08 (4), gamma = 85.64 (5) degrees, V = 1095.8 A3, Z = 4, Dx = 1.32 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 2.18 cm-1, F(000) = 464, T = 138 (2) K, R = 0.062 for 3264 data. The two molecules in the asymmetric unit are crystallographically independent, but their conformations are similar.(ABSTRACT TRUNCATED AT 250 WORDS)