Transmural distribution of iron in the hypoxic and reoxygenated rabbit left ventricular myocardium

Transmural distribution of low molecular weight iron (LMWI), total iron, and protein carbonyls (PC) was investigated in the perfused rabbit heart under aerobic conditions, and after 60 min hypoxia followed or not by 3 min reoxygenation. In the aerobic perfused hearts, LMWI, total iron and PC did not show significant transmural differences. Hypoxia increased LMWI and PC levels, which were significantly higher in the subendocardium than in the subepicardium; further significant changes were not observed after reoxygenation. Total iron showed no transmural difference and was not significantly affected by both hypoxia and reoxygenation. Free iron was undetectable in the myocardial effluent of all experimental groups. Thus, hypoxia favors myocardial iron decompartmentalisation and oxidative stress, which are significantly greater in the inner than in the outer ventricular layers. Such findings may add further insight into the problem of the vulnerability of the mammalian subendocardium to injury induced by oxygen deprivation.     

Silver derivatives of tris(pyrazol-1-yl)methanes. A silver(I) nitrate complex containing a tris(pyrazolyl)methane coordinated in a bridging mode

The reaction of AgX (X=ClO₄, NO₃ or SO₃CH₃) acceptors with excesses of tris(pyrazol-1-yl)methane ligands L (L=CH(pz)₃, CH(4-Mepz)₃, CH(3,5-Me₂pz)₃, CH(3,4,5-Me₃pz)₃ or CH(3-Mepz)₂(5-Mepz)) yields 1:1 [AgX(L)], 2:1 [Ag(L)₂]X or 3:2 [(AgX)₂(L)₃] complexes. The ligand to metal ratio in all complexes is dependent on the number and disposition of the Me substituents on the azole ring of the neutral ligand and on the nature of the Ag(I) acceptor. All complexes have been characterized in the solid state as well as in solution (medium- and far-IR, ¹H and ¹³C NMR and conductivity determinations) and the solid-state structures of [Ag(NO₃){(pz)₃CH}]_(∞/∞) and [Ag{(3,5-Me₂pz)₃CH}₂]NO₃ determined by single crystal X-ray studies.     

Synergistic Antibacterial and Anti-Inflammatory Activity of Temporin A and Modified Temporin B In Vivo

Temporins are antimicrobial peptides secreted by the granular glands of the European red frog (Rana temporaria). They are 10–14 amino acid long polypeptides active prevalently against gram positive bacteria. This study shows that a synthetic temporin B analogue (TB-YK), acquires the capacity to act in synergism with temporin A and to exert antimicrobial and anti-inflammatory activity in vivo against gram positive and gram negative bacteria. Administration of 3.4 mg/Kg of temporin A (TA)+1.6 mg/Kg TB-YK, given to individual mice concurrently with a lethal dose of bacteria (gram positive or negative), rescued 100% of the animals. More importantly, the same doses of temporins, administered one week after experimental infection with a sub lethal dose of bacteria, sterilized 100% of the animals within 3–6 days. Also, it is described an animal model based on the use of sub lethal doses of bacteria, which closely mimics bacterial infection in humans. The model offers the possibility to test in a preclinical setting the true potential of TA and TB-YK in combination as antimicrobial and anti-inflammatory agents.     

Excitatory Amino Acid Release from Rat Hippocampal Slices as a Consequence of Free-Radical Formation

The release of D-[3H]aspartate, [3H]noradrenaline, and of endogenous glutamate and aspartate from rat hippocampal slices was significantly increased when the slices were incubated with xanthine oxidase plus xanthine to produce superoxide and hydroxyl free radicals locally. Allopurinol, a specific xanthine oxidase inhibitor, the hydroxyl-radical scavenger D-mannitol, or the superoxide-radical scavenger system formed by superoxide dismutase plus catalase prevented this release. These results suggest that endogenous excitatory amino acids are released consequent to the formation of free radicals. The excess of glutamate and aspartate released by this mechanism could be one of the factors contributing to the death of neurons after anoxic or ischemic injuries.     

The <Emphasis Type="Italic">Nramp1</Emphasis>AA genotype confers susceptibility to <Emphasis Type="Italic">Brucella abortus</Emphasis> in water buffalo

The 3′ untranslated region of the water buffalo Nramp1 (natural resistance-associated macrophage protein 1) gene contains two alleles (Nramp1A and Nramp1B), as detected by the denaturing gradient gel electrophoresis (DGGE) technique. The Nramp1BB genotype is associated with resistance of water buffalo to the intracellular pathogen Brucella abortus. This article provides evidence that the Nramp1AA genotype is associated with susceptibility to the same pathogen. Susceptibility or resistance of water buffalo to B. abortus was established by agglutination, complement fixation, and skin tests. The Nramp1 genotype was established by DGGE analysis. The association between the Nramp1AA genotype and susceptibility to B. abortus was demonstrated in two independent population samples (152 cases and 281 controls; 87 cases and 124 controls, respectively). Macrophages from Nramp1AA subjects displayed a lower Nramp1 mRNA level when compared with macrophages from Nramp1BB subjects. Also, monocytes and macrophages from Nramp1AA subjects displayed a higher number of viable intracellular bacteria in comparison with monocytes and macrophages from Nramp1BB animals, providing biological significance to the results from association studies.