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Summary: Phosphorylation of protein tyrosines is an important modulatory process for cell signaling and other cellular functions. Rat brain regions were examined for altered protein phosphotyrosines, using Western blot analysis and microwave irradiation to limit postmortem alterations, after administration of two convulsants: lithium plus pilocarpine or kainic acid (KA). Most phospho-tyrosine proteins were unaltered by these treatments, but there was a large, specific increase in the tyrosine phosphorylation of a 40-Kd protein. This increase was evident in all three regions examined: cerebral cortex, hippocampus, and striatum; it occurred abruptly with onset of generalized status epilepticus (SE) and remained elevated for at least 90 min. Most of the tyrosine phosphorylated 40-Kd protein was in the cytosolic fraction. These results demonstrate a large, specific effect of chemically induced seizures on a single phosphotyrosine protein in rat brain. RESUME La phosphorylation des tyrosines proteiques est un processus de modulation important pour la communication intercellulaire et d'autres fonctions cellulaires. Des regions cerebrales de rat ont ete examinees a la recherche de modification de phosphoty-rosines proteiques, au moyen d'une analyse de type Western blot et d'une irradiation par micro-ondes afin de limiter les alterations post-mortem, apres administration de 2 produits convulsivants, lithium + pilocarpine ou acide kainique. La plupart des proteines avec phosphotyrosines n'etaient pas modifees par ces traitements, les auteurs ont constate une augmentation importante, specifique de la phosphorylation de la tyrosine dans une proteine 40 kD. Cette elevation a ete mise en eAvidence au niveau des 3 regions cerebrates examinees, le cortex cerebral, ľhippo-campe et le striatum. Cette augmentation s'est produite de facon brutale au moment de la mise en place d'un etat de mal generalise, ľeievation s'est maintenue pendant au moins 90 mn. La majorite de la proteine 40 kD avec tyrosine phosphoryiee a ete trouvee au niveau de la fraction cytosolique. Ces resultats demontrent un effet important, specifique des crises induites par convulsivants chimiques, sur une proteine particuliere du cerveau du rat.

The effects of substitution of X = C by Si or Ge in X(CH(3))(3) moieties attached to the formal double bond of 3,3-dimethylcyclopropene are examined. Regularities in observed trends of vibrational frequencies implicating the moieties containing the X atom, as the X atomic mass is increased, are extrapolated to X = Sn. The results of this extrapolation made it possible to assign the known experimental vibrational frequencies of 3,3-dimethyl-1-(trimethylstannyl)cyclopropene and 3,3-dimethyl-1,2-bis(trimethylstannyl)cyclopropene.

Pulmonary injury occurs after vascular surgery, with xanthine oxidase (an oxidant generator) released from reperfusing liver and intestines mediating a significant component of this injury. Because halogenated anesthetics have been observed to enhance oxidant-mediated injury in vitro, the authors hypothesized that desflurane would increase alveolar-capillary membrane permeability mediated by circulating xanthine oxidase after thoracic occlusion and reperfusion.Rabbits were assigned to one of five groups: aorta occlusion groups administered desflurane (n=14), desflurane and tungstate (xanthine oxidase inactivator, n=12), fentanyl plus droperidol (n=13), and two sham-operated groups (desflurane, n=7 and fentanyl plus droperidol, n=7). Aortic occlusion was maintained for 45 min with a balloon catheter, followed by 3 h of reperfusion. Alveolar-capillary membrane permeability was assessed by measurement of bronchoalveolar lavage fluid protein. Xanthine oxidase activity was determined in plasma and lung tissue. Ascorbic acid content (an antioxidant) was determined in lung tissue.Desflurane was associated with significantly increased alveolar-capillary membrane permeability after aortic occlusion-reperfusion when compared with the fentanyl plus droperidol anesthesia or sham-operated groups (P0.05). Inactivation of xanthine oxidase abrogated the alveolar-capillary membrane compromise associated with desflurane. Although significantly greater than for sham-operated animals, plasma xanthine oxidase activities released after aortic occlusion-reperfusion were not different between the two anesthetics. There were no anesthetic-associated differences in lung tissue xanthine oxidase activity. However, desflurane anesthesia resulted in a significant reduction in lung ascorbic acid after aortic occlusion-reperfusion compared with the sham-operated animals.Desflurane anesthesia increased xanthine oxidase-dependent alveolar-capillary membrane compromise after aortic occlusion-reperfusion in concert with depletion of a key tissue antioxidant.

We hypothesized that multiple organ injury and concentrations of xanthine oxidase (an oxidant-generating enzyme released after hepatoenteric ischemia) would be decreased by the administration of a bolus of a colloid solution at reperfusion.Randomized, masked, controlled animal study.University-based animal research facility.Fifty-four New Zealand white male rabbits, weighing 2 to 3 kg.Anesthetized rabbits were assigned to either the hepatoenteric ischemia-reperfusion group (n = 27) or the sham-operated group (n = 27). Hepatoenteric ischemia was maintained for 40 mins with a balloon catheter in the thoracic aorta, followed by 3 hrs of reperfusion. Each group was randomly administered a bolus of one of three fluids at the beginning of reperfusion: Hextend (hetastarch solution); 5% human albumin; or lactated Ringer's solution. The investigators were masked as to the identity of the fluid administered.Multiple organ injury was assessed by the release of lactate dehydrogenase activity into the plasma and by indices of gastric and pulmonary injury. Circulating lactate dehydrogenase activity was significantly greater (p.001) in animals receiving lactated Ringer's solution than in rabbits receiving either colloid solution. Gastric injury (tissue edema, Histologic injury Score) was significantly decreased (p.01) by administration of both colloid solutions. Lung injury (bronchoalveolar lavage lactate dehydrogenase activity) was significantly decreased (p.05) by the hetastarch solution administration. The hetastarch solution administration resulted in 50% less xanthine oxidase activity release during reperfusion compared with albumin or lactated Ringer's solution administration (p.001).We conclude that multiple organ injury and xanthine oxidase release after hepatoenteric ischemia-reperfusion are decreased by colloid administration.