Synthesis of [Cu-2(Me-2[9]aneN(2)S)(2)(OH)(2)] (PF6)(2), a hydroxo-bridged copper(II) complex of N,N '-dimethyl-1-thia-4,7-diazacyclononane (Me-2[9]aneN(2)S). X-ray structural analysis, magnetic susceptibility, EPR and visible spectroscopy

The bis(mu-hydroxo) complex [Cu-2(Me-2[9]aneN(2)S)(2)(OH)(2)](PF6)(2) (Me-2[9]aneN(2)S = N,N'-dimethyl-1-thia-4,7-diazacyclononane) results after reaction of [Cu(Me-2[9]aneN(2)S)(MeCN)] (PF6) with dioxygen at -78 degrees C in acetonitrile. The complex has been characterized by X-ray crystallography: orthorhombic, space group Pnma, with a 18.710(3), b 16.758(2), c 9.593(2) Angstrom, and Z = 4. The structure refined to a final R value of 0.051. The complex contains two copper(II) ions bridged by two hydroxo groups with Cu ... Cu 2.866(1) Angstrom. The solid-state magnetic susceptibility study reveals ferromagnetic coupling, the fitting parameters being J = +46+/-5 cm(-1), g = 2.01+/-0.01 and theta = -0.58+/-0.03 K. The frozen-solution e.p.r. spectrum in dimethyl sulfoxide is characteristic of a monomeric copper(II) ion (g(parallel to) 2.300, g(perpendicular to) 2.063; A(parallel to) 156.2 x 10(-4) cm(-1), A(perpendicular to) 9.0 x 10(-4) cm(-1)) with an N2O2 donor set. Thioether coordination to the copper(II) in solution is supported by the presence of an intense absorption assigned to a sigma(S)-->Cu-II LMCT transition at c. 34000 cm(-1). The single-crystal spectrum of [Cu-2(Me-2[9]aneN(2)S)(2)(OH)(2)] (PF6)(2) (273 K) reveals d-->d transitions at 14500 and 18300 cm(-1) and a weak pi(S)-->Cu-II charge-transfer band at approximately 25000 cm(-1).

Antioxidant behaviour of thia fatty acids

Eight thia fatty acids and other sulfides have been studied as inhibitors of autoxidation of arachidonic acid. The inhibitors extend the lag phase of the oxidation, to varying degrees. A carboxyl group in the vicinity of the sulfur reduces the antioxidant activity, while unsaturated sulfides are more effective than their saturated analogues. The results are consistent with the sulfides acting to reduce fatty acid hydroperoxides, which otherwise accumulate during the early stages of reaction and propagate the free-radical oxidation process.

The status of the Diplosentidae (Acanthocephala : Palaeacanthocephala) and a new family of acanthocephalans from Australian wrasses (Pisces : Labridae)

The status and composition of the Diplosentidae Tubangui et Masilungan, 1937 are reviewed. The type species of the type genus, Diplosentis amphacanthi Tubangui et Masilungan, 1937 from Siganus canaliculatus (Park, 1797) in the Philippines, is concluded to have been described inaccurately,in supposedly possessing, only two cement glands and lemnisci enclosed in a membranous sac. The species is almost certainly very close to species of Neorhadinorhynchus yamaguti, 1939 and Sclerocollum Schmidt of Paperna, 1978 which have also been reported from siganids from the tropical Indo-Pacific. Species of these genera have four cement glands and unexceptional lemnisci. As a result, Diplosentis Tubangui et Masilungan, 1937 is best considered to have affinities with the Cavisomidae Meyer, 1932. The Cavisomidae has priority over the Diplosentidae; thus the Diplosentidae becomes a synonym of the Cavisomidae. Neorhadinorhynchus and Sclerocollum are considered synonyms of Diplosentis. The affinities of the other species and genera formerly included in the Diplosentidae (other species of Diplosentis, Allorhadinorhynchus Yamaguti, 1959, Amapacanthus Salgado-Maldonado et Santos, 2000, Pararhadinorhynchus Johnston et Edmonds, 1947, Golvanorhynchus Noronha, do Fabio et Pinto, 1978 and Slendrorhynchus Amin et Soy, 1996) are discussed. It is concluded that all but Pararhadinorhynchus, two species of Diplosentis and Amapacanthus can be accommodated elsewhere satisfactorily. A new family, Transvenidae, is proposed for a small group of acanthocephalans that genuinely possess only two cement glands. Transvena annulospinosa gen. n., sp. n. is described from the labrids Anampses neoguinaicus Bleeker, 1878 (type host), A. geographicus Valenciennes, 1840, A. caeruleopunctatus Ruppell, 1829, Hemigymnus fasciatus (Bloch, 1792), and H. melapterus (Bloch, 1791) from the Great Barrier Reef, Queensland, Australia. Transvena gen. n. is distinguished from all other acanthocephalan genera by having a combination of a single ring of small spines on its trunk near or at the junction between the neck and trunk, two cement glands, a double-walled proboscis receptacle and hooks which decrease in length from the apex to the base of the proboscis. A second new genus within the Transvenidae, Trajectura, is proposed for T. perinsolens sp. n. from Anampses neoguinaicus, also from the Great Barrier Reef. Trajectura gen. n. is distinguished by the possession of only two cement glands and an anterior conical projection (function unknown) on the females. Diplosentis ikedai Machida, 1992 shares these characters and is recombined as Trajectura ikedai comb. n. Pararhadinorhynchus is transferred to the Transvenidae and Diplosentis manteri Gupta et Fatma, 1979 is recombined as Pararhadinorhynchus manteri comb. n.

Slowed conduction and ventricular tachycardia after targeted disruption of the cardiac sodium channel gene Scn5a

Voltage-gated sodium channels drive the initial depolarization phase of the cardiac action potential and therefore critically determine conduction of excitation through the heart. In patients, deletions or loss-of-function mutations of the cardiac sodium channel gene, SCN5A, have been associated with a wide range of arrhythmias including bradycardia (heart rate slowing), atrioventricular conduction delay, and ventricular fibrillation. The pathophysiological basis of these clinical conditions is unresolved. Here we show that disruption of the mouse cardiac sodium channel gene, Scn5a, causes intrauterine lethality in homozygotes with severe defects in ventricular morphogenesis whereas heterozygotes show normal survival. Whole-cell patch clamp analyses of isolated ventricular myocytes from adult Scn5a(+/-) mice demonstrate a approximate to50% reduction in sodium conductance. Scn5a(+/-) hearts have several defects including impaired atrioventricular conduction, delayed intramyocardial conduction, increased ventricular refractoriness, and ventricular tachycardia with characteristics of reentrant excitation. These findings reconcile reduced activity of the cardiac sodium channel leading to slowed conduction with several apparently diverse clinical phenotypes, providing a model for the detailed analysis of the pathophysiology of arrhythmias.