Effect of hematoporphyrin derivative and light on sulfhydryl groups in brain tumour cells

Effect of hematoporphyrin derivative (HpD) and light on sulfhydryl (SH) groups in brain tumor cells was studied. Sulfhydryl groups were measured by 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and a fluorescent probe 3,4-maleimidylphenyl-4-methyl-7-diethylaminocoumarin (CPM). Incubation of cells with HpD in dark resulted in the loss of DTNB as well as CPM reactive SH groups. After 2 hr of incubation DTNB reactive SH groups showed a negligible change while a continuous decrease was observed in CPM reactive SH groups. Cells treated with HpD showed a further degradation of SH groups upon light irradiation. A comparison of cytotoxicity and SH groups under identical conditions showed that blockage of SH groups by HpD binding is not leathal to the cells where as photoinduced cell death was observed on photodegradation of SH groups.     

In vivo pharmacology of an angiotensin AT1 receptor antagonist with balanced affinity for AT2 receptors

L-163,017 (6-[benzoylamino]-7-methyl-2-propyl-3-[[2'-(N-(3-methyl-1-butoxy) carbonylaminosulfonyl)[1,1']-biphenyl-4-yl]methyl]-3H-imidazo[4,5- b]pyridine) is a potent, orally active, nonpeptide angiotensin II receptor antagonist. Conscious rats and dogs were dosed p.o. and i.v.; in both species the plasma bioequivalents are similar at the angiotensin AT1 and AT2 receptor sites indicating balanced activity is maintained in vivo. L-163,017 prevents the pressor response to intravenous (i.v.) angiotensin II in the conscious rat, dog, and rhesus monkey. L-163,017 also significantly reduces blood pressure in a renin-dependent model of hypertension, similar to an angiotensin converting enzyme inhibitor (Enalapril) and an angiotensin AT1 receptor-selective antagonist (L-159,282). These studies indicate that neither the angiotensin AT2 receptor nor bradykinin is important in the acute antihypertensive activity of angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists.     

In vitro corrosion behavior and microstructure examination of a gallium-based restorative

Concerns of mercury toxicity have led to the development of gallium-based restorative materials to replace dental amalgam. A new gallium-based dental restorative, Galloy, was compared with a high-copper amalgam, Permite, for anodic polarization behavior in deoxygenated Ringer's solution and by immersion testing in normal Ringer's solution at 37 degrees C. Corrosion products were analyzed using energy dispersive X-ray spectrometry and transmission electron diffraction. The data from both sources were consistent with the presence of alpha-Ga2O3 and SnO2 as the primary corrosion products of Galloy. Anodic polarization behavior of Galloy- and Permite-coupled specimens suggests that coupling Galloy with the more noble Permite amalgam may cause accelerated electrochemical corrosion and that Galloy is more corrosion prone than Permite.     

Peak mitral inflow velocity predicts mitral regurgitation severity

Glutamate transport is a primary mechanism for the synaptic inactivation of glutamate. Excitatory amino acid transporter 4 (EAAT4) is a novel glutamate transporter with properties of a ligand-gated chloride channel that was recently cloned from human brain. Here we report the cloning of rat EAAT4 (rEAAT4) cDNA from rat cerebellum. The nucleotide sequence of rEAAT4 was 88% identical to the human sequence, and the predicted peptide was 89% identical to the human protein. The transport activity encoded by rEAAT4 has high affinity for L-glutamate. In Xenopus laevis oocytes expressing rEAAT4, L-glutamate and other transporter substrates elicited a current predominantly carried by chloride ions. Like human EAAT4, the rEAAT4 mRNA was largely restricted to cerebellar Purkinje cells; the rEAAT4 protein was localized to Purkinje cell somas and dendrites.     

Inhibition of transforming growth factor beta 1 induction by dietary vitamin E in unilateral ureteral obstruction in rats

OBJECTIVE: To assess the effect of incomplete, midsagittal fractures of the proximal phalanx (P1) on racing performance in Standardbreds. DESIGN: Retrospective cohort study. ANIMALS: 49 Standardbred horses admitted to the George D. Widener Hospital for Large Animals between July 1986 and December 1992 with a definitive radiographic diagnosis of an incomplete, midsagittal fracture of P1 and a known method of treatment. PROCEDURE: Performance index and racing time were compared before and after diagnosis and treatment of fracture, using ANOVA that controlled for the effects of horse, gender, age, track length, and track condition. RESULTS: Expected racing time increased by 0.7 seconds and performance index decreased by 0.7 points, although controlling for factors known to affect racing performance had a substantial impact on these results. CLINICAL IMPLICATIONS: Standardbreds with incomplete, midsagittal fractures of P1 have a favorable prognosis for return to racing; recovered horses will likely have slower racing times and decreased performance indices.     

Evolutionary shifts in three major structural features of the mitochondrial genome among iguanian lizards

A phylogenetic tree for major lineages of iguanian lizards is estimated from 1,488 aligned base positions (858 informative) of newly reported mitochondrial DNA sequences representing coding regions for eight tRNAs, ND2, and portions of ND1 and COI. Two well-supported groups are defined, the Acrodonta and the Iguanidae (sensu lato). This phylogenetic hypothesis is used to investigate evolutionary shifts in mitochondrial gene order, origin for light-strand replication, and secondary structure of tRNACys. These three characters shift together on the branch leading to acrodont lizards. Plate tectonics and the fossil record indicate that these characters changed in the Jurassic. We propose that changes to the secondary structure of tRNACys may destroy function of the origin for light-strand replication which, in turn, may facilitate shifts in gene order.