Advanced glycation end products, oxidative stress and metalloproteinases are altered in the cerebral microvasculature during aging

Biological aging is associated with an increased incidence of cerebrovascular disease. Recent findings indicate that oxidative stress promoting age-related changes of cerebral circulation are involved in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease. The aim of this study was to evaluate the contribution of cerebral microvessels to the oxidative stress during brain aging, by: (i) assessment of precursors for advanced glycation end products (AGE) formation, (ii) activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione disulfide reductase (GR), and (iii) the activities of metalloproteinases (MMPs), MMP-2 and MMP-9, involved in synaptogenesis and memory consolidation. The experiments were performed on two groups of male Wistar rats: 15 young (3-6 months old) and 15 aged (18-24 months old) animals. The cerebral microvessels were isolated by mechanical homogenization, the concentration of protein carbonyls and the activity of antioxidant enzymes were evaluated by spectrophotometry, and gelatin SDS-PAGE zymography was employed to evaluate MMP-2 and MMP-9 activities. The results showed that, by comparison with young rats, aged brain microvessels contain: (i) approximately 106 % increase of protein carbonyls production; (ii) approximately 68% higher GPx activity, unmodified activities of SOD and GR; (iii) approximately 30% diminishment in MMP-2 activity, and the specific occurrence of MMP-9 enzyme. The data suggest that the age-related changes of microvessels could increase the propensity for cerebral diseases and might represent, at least in part, a prerequisite for the deterioration of mental and physical status in the elderly.     

Murine T-lymphocytes express vasoactive intestinal peptide receptor 1 (VIP-R1) mRNA

Vasoactive intestinal peptide (VIP), a neuropeptide present in primary and secondary lymphoid organs has been previously reported to inhibit IL-2 and IL-4 production, as well as the proliferation of mitogen- or antigen-stimulated T-cells. Binding studies suggested that the immunoregulatory effects of VIP are mediated through specific VIP-binding sites present on lymphocyte subpopulations. Here we report on the expression of VIP-R1 mRNA in various murine lymphocyte subpopulations. By using RT-PCR, RNase protection assay, cDNA cloning, and sequence analysis, we show that stimulated and unstimulated murine spleen cells, thymocytes, CD4⁺ and CD8⁺ T-cells express VIP-R1. The VIP-R1 fragment amplified from murine brain, thymocytes, spleen cells and CD4⁺ T-cells share identical nucleotide sequences, and a high degree of homology with the corresponding nonlymphoid rat and human VIP-R1 sequences. The expression of VIP-R1 in thymocytes and peripheral lymphocytes, and especially in the CD4⁺ T-cell subset supports the idea that VIP produced or released locally in the lymphoid microenvironment could directly affect cytokine production and proliferation of T-lymphocytes.     

Hemagglutination assay for human serum fibronectin

A hemagglutination assay for human serum fibronectin (Fn) is described. The assay is based on the capacity of Fn to bind to gelatin. Purified and human serum Fn agglutinate chromic chloride treated sheep red cells coated with gelatin in a quantitative and reproducible manner. The lowest Fn concentration giving positive hemagglutination was found to be 7 micrograms/ml, a sensitivity making it suitable for measurement of Fn in both normal and pathologic sera. The assay is simple and rapid and does not require specialized equipment.     

Uveal melanoma

The paper present a clinic and histological study, including all cases of uveal malignant tumours, hospitalized in Ophthalmological Clinic of Craiova in the last 15 years. The follow-up period of cases were 4 years. The diagnosis was established by clinic and paraclinic examination (imaging methods-- MRI, CT, Echo) and histologic examination. The histologic examination has been done for all cases. There were investigated several parametres: tumour cytology, the level of pigmentation, intravascular embolus, sclera infiltration, vascular invasion, vascular pattern, tumoral necrosis, mitotic activity. The histologic aspects of tumoral progression were: the high level mitotic activity, high surface area of intratumoral necrosis, the infiltrative process to the vessels, sclera, and ciliary body. The arcuat and network vascular patterns were involved in the systemic metastasis and local invasion. The most predominant type of cellularity related with a severe evolution of cases were the epithelioid cells and the mixed type cells.     

Increased susceptibility to proteolytic action of gastric superficial mucosa after sialic acid release

The purpose of this investigation was to find out (1) whether a pH dependent, chemical extraction, of sialic acid might occur in the superficial mucous layer of gastric mucosa as a result of prolonged states of hyperacidity of gastric juice and (2) whether the release of sialic acid could induce increased susceptibility of this mucin to proteolytic action. We have demonstrated that the superficial layer of gastric mucosa in a group of selected normoacid subjects exhibits an important resistance to pepsin, trypsin, and papain digestion. This resistance decreases after sialidase incubation and especially after mild acid hydrolysis in 0.02 N HCl at pH 1.6. On the other hand, the superficial layer of gastric mucosa in a group of selected hyperacid subjects exhibits both an important loss of mucin basophilia and an augmented susceptibility to prteolytic action.The authors are indebted to Ernestina Ponova for skilled technical assistance and to Louisa Schioiu for the statistical treatment of the results.     

The cellular mechanisms involved in the vasodilator effect of nebivolol on the renal artery

Nebivolol is known as a highly selective beta1-adrenoceptor antagonist. Based on the reported vasodilator effect of nebivolol, we examined the cellular mechanisms by which the drug induces renal artery vasodilation, an issue of potential relevance for condition associated with high blood pressure. To this purpose, myograph and patch-clamp techniques were used. Small mouse renal arteries were placed in the myograph chamber, and after the optimal concentration for the vasodilator effect of nebivolol was established (50 microM), the arteries were further investigated to assess the potential contribution of nitric oxide (NO) and of Ca2+ ions to the nebivolol-induced effect, by exposing the arteries to the specific inhibitors such as N(G)-nitro-L-arginine methylester (L-NAME, 100 microM), ethylenglycol-bis-(beta-amino-ethylen ester) N,N'-tetraacetic acid (EGTA, 4 microM) and thapsigargin (1 microM). The expression of NO synthase was evaluated by the Western-blot technique. Using myograph and patch-clamp techniques applied on intact renal artery, we investigated the role of beta2-adrenoceptors, of myoendothelial junctions and of Ca(2+)-activated K+ channels in the vasodilatory effects of nebivolol, using 100 microM butoxamine, 40 microM 18 beta-glycyrrhetinic acid, 1 mM tetraethylammonium, and 100 nM iberiotoxin, respectively. The results showed that the cellular mechanisms of the vasodilator effect of nebivolol on the renal artery entail (i) activation of the endothelial beta2-adrenoceptor, (ii) participation of [Ca2+]i, (iii) increase in NO and eNOS, and (iv) activation of Ca(2+)-activated K+ channels. The cellular mechanisms underlying vasodilator effect of nebivolol on the artery explain the favorable effect of this drug in hypertension.