Angiotensin-(1-7) prevents development of severe hypertension and end-organ damage in spontaneously hypertensive rats treated with L-NAME

We examined the influence of chronic treatment with ANG-(1-7) on development of hypertension and end-organ damage in spontaneously hypertensive rats (SHR) chronically treated with the nitric oxide synthesis inhibitor L-NAME (SHR-L-NAME). L-NAME administered orally (80 mg/l) for 4 wk significantly elevated mean arterial pressure (MAP) compared with SHR controls drinking regular water (269 +/- 10 vs. 196 +/- 6 mmHg). ANG-(1-7) (24 microg x kg(-1) x h(-1)) or captopril (300 mg/l) significantly attenuated the elevation in MAP due to L-NAME (213 +/- 7 and 228 +/- 8 mmHg, respectively), and ANG-(1-7) + captopril completely reversed the L-NAME-dependent increase in MAP (193 +/- 5 mmHg). L-NAME-induced increases in urinary protein were significantly lower in ANG-(1-7)-treated animals (226 +/- 6 vs. 145 +/- 12 mg/day). Captopril was more effective (96 +/- 12 mg/day), and there was no additional effect of captopril + ANG-(1-7) (87 +/- 5 mg/day). The abnormal vascular responsiveness to endothelin-1, carbachol, and sodium nitroprusside in perfused mesenteric vascular bed of SHR-L-NAME was improved by ANG-(1-7) or captopril, with no additive effect of ANG-(1-7) + captopril. In isolated perfused hearts, recovery of left ventricular function from 40 min of global ischemia was significantly better in ANG-(1-7)- or captopril-treated SHR-L-NAME, with additive effects of combined treatment. The beneficial effects of ANG-(1-7) on MAP and cardiac function were inhibited when indomethacin was administered with ANG-(1-7), but indomethacin did not reverse the protective effects on proteinuria or vascular reactivity. The protective effects of the ANG-(1-7) analog AVE-0991 were qualitatively comparable to those of ANG-(1-7) but were not improved over those of captopril alone. Thus, during reduced nitric oxide availability, ANG-(1-7) attenuates development of severe hypertension and end-organ damage; prostaglandins participate in the MAP-lowering and cardioprotective effects of ANG-(1-7); and additive effects of captopril + ANG-(1-7) on MAP, but not proteinuria or endothelial function, suggest common, as well as different, mechanisms of action for the two treatments. Together, the results provide further evidence of a role for ANG-(1-7) in protective effects of angiotensin-converting enzyme inhibition and suggest dissociation of factors influencing MAP and those influencing end-organ damage.     

Binding of Eu3+ to cardiac sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPase-laser excited Eu3+ spectroscopic studies.

The binding of Eu3+ with Ca2+-stimulated, Mg2+-dependent adenosine triphosphatase ([Ca2+ + Mg2+]-ATPase) of cardiac sarcoplasmic reticulum (SR) has been investigated using direct laser excited Eu3+ luminescence. Eu3+ is found to inhibit both Ca2+-dependent ATPase activity and Ca2+-uptake in a parallel manner. This is attributed to the binding of Eu3+ to the high affinity Ca2+-binding sites. The Ki for Ca2+-dependent ATPase is approximately 50 nM. The 7F0----5D0 excitation spectrum of Eu3+ in cardiac SR shows a peak at 579.3 nm, as compared to 578.8 nm in potassium-morpholino propane sulfonic acid (K-MOPS) pH 6.8. Upon binding with cardiac SR, Eu3+ shows an increase in fluorescence intensity as well as in lifetime values. The fluorescence decay of bound Eu3+ exhibits a double-exponential curve. The apparent number of water molecules in the first coordination sphere of Eu3+ in SR is 2.8 for the short component and 1.0 for the long component. In the presence of ATP, a further increase in fluorescence lifetimes is observed, and the number of water molecules in the first coordination sphere of Eu3+ is reduced further to 1.3 and 0.5. The double exponential nature of the decay curve and the different number of water molecules coordinated to Eu3+ for both decay components suggest that Eu3+ binds to two sites and that these are heterogeneous. The reduction in the number of H2O ligands in the presence of ATP shows a change in the molecular environment of the Eu3+-binding sites upon phosphoenzyme formation, with a movement of Eu3+ to an occluded site on the enzyme.     

Purification and characterization of the 45,000-dalton fragment from tryptic digestion of (Ca2++Mg2+)-adenosine triphosphatase of sarcoplasmic reticulum

Summary Tryptic digestion of (Ca²⁺+Mg²⁺)-ATPase from sarcoplasmic reticulum of rabbit skeletal muscle has previously been shown to cleave the enzyme initially into a 55,000-dalton fragment and a 45,000-dalton fragment. In the present study the two fragments are solubilized in sodium dodecyl sulfate (SDS) and separated by preparative polyacrylamide gel electrophoresis. The 45,000-dalton fragment is found to be a relatively nonselective, divalent cation-dependent ionophore when incorporated into an oxidized cholesterol membrane (BLM). Ionophoric activity of this fragment is inhibited by low concentrations of LaCl₃, HgCl₂, and various reducing agents. There appears to be one or two relatively inaccessible disulfide bonds in the 45,000-dalton fragment that are essential for transport. Addition of reducing agents inhibits the ionophoric activity of the succinylated undigested enzyme and the 45,000-dalton fragment, but has no effect on the 55,000-dalton fragment. These experiments imply that the 45,000-dalton fragment and the 55,000-dalton fragment are in a series arrangement in the membrane.     

Incidence of virulence factors and antibiotic resistance among Enterococci isolated from food

The incidence of virulence factors among 48 Enterococcus faecium and 47 Enterococcus faecalis strains from foods and their antibiotic susceptibility were investigated. No strain was resistant to all antibiotics, and for some strains, multiple resistances were observed. Of E. faecium strains, 10.4% were positive for one or more virulence determinants, compared to 78.7% of E. faecalis strains. Strains exhibiting virulence traits were not necessarily positive for all traits; thus, the incidence of virulence factors may be considered to be strain specific.     

Librational motions of membrane-embedded Ca2+-ATPase of sarcoplasmic reticulum labeled with fluorescein isothiocyanate

Continuing our investigation of the relationships between internal motions and functional properties of soluble and membrane-bound proteins we have explored the lifetimes and correlation times associated with the fluorescence emission of fluorescein-labeled Ca2+-dependent ATPase of sarcoplasmic reticulum. The emission was characterized by two lifetime components near 1.8 and 4.1 ns, probably due to exposure of the probe to environments of different polarities. The time-dependent anisotropy showed the presence of two correlation times near 0.8 and 6.6 ns. The shorter correlation time was due to motions of the probe around its point of attachment on the surface of the protein. The longer correlation time indicated the presence of internal motions of the protein. Both lifetimes and correlation times were insensitive to temperature between 2 and 10 degrees C. They were also insensitive to addition and removal of 100 microM free Ca2+.     

Isolation of a Ca2+ carrier from calf heart inner mitochondrial membrane

A protein has been isolated from calf heart inner mitochondrial membrane with the aid of an electron paramagnetic resonance (EPR) assay based on the relative binding properties of Ca2+, Mn2+, and Mg2+ to the protein. The molecular weight of this protein has been estimated to be about 3000 by urea/sodium dodecyl sulfate-gel electrophoresis and amino acid analysis. The isolated protein has been shown to have high affinity and high specificity for Ca2+ (Jeng, A. Y., Ryan T. E., and Shamoo, A. E. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 2125-2129). However, the protein was found to be contaminated with a large amount of phospholipids. There are 150 mol of phospholipids associated with each mole of the protein. The protein is delipidated using Sephadex LH-20 column chromatography. The contaminating phospholipids can be reduced to 0.1 mol of phospholipids/mol of protein. There are no detectable free fatty acids, hexosamines, or sialic acids associated with the delipidated protein. This protein is named "calciphorin," meaning calcium ionophore protein.     

Effect of the Deposition Temperature on Ammonia Gas Sensing Based on SnO2/Porous Silicon

Plasmonics - Enhancing the performance of the room temperature gas sensing that based on a wide surface area of the metal oxide semiconductor is the most important field. In this paper, tin dioxide...     

Expression of IL-32 modulates NF-κB and p38 MAP kinase pathways in human esophageal cancer

BackgroundEsophageal cancer is the seventh leading cause of cancer death in males in USA, and there is a strong link has been demonstrated between inflammation and esophageal cancer, interleukin (IL)-32 is a recently described pro-inflammatory cytokine characterized by the induction of nuclear factor NF-κB activation, the p38MAPK also plays an important role in key cellular processes related to inflammation and cancer. We investigated whether the IL-32 expression may be involved in esophageal carcinogenesis through modulates the activity of NF-κB and p-p38 MAPK.MethodMalignant esophageal tissue and blood samples were obtained from 65 operated untreated patients, normal samples was obtained from 35 patients operated for other reasons as control. IL-32 expression visualized by immunohistochemistry, Real time RT–PCR for IL-32 mRNA expression, NF-κB phosphorylation and phosphorylated p38mapk were analyzed by immunoblotting, ELISA for further detection IL-32 and cytokines (TNF-α, IL-1β, IL-6 and IL-8) concentration in the patient’s sera.ResultsIL-32 expression was increased in immunohistochemical staining for malignant esophageal tissue and it’s correlated with the relative expression level of IL-32 mRNA P = 0.007, the P-NF-κB level elevated in tumor tissue compared with control and no difference in the total NF-κB level P = 0.003 while the IL-32 up-regulated the P-pNF-κB in the esophageal tumor P = 0.005. There is increase in p-p38MAPK activation underlying IL-32 expression in tumor P = 0.004, but no change in total p38 MAPK in malignant esophagus. The plasma level of IL-32 expression was increased in malignant esophageal patients P = 0.01, with increased in the levels of the cytokines TNF-α, IL-6, and IL-1β P<0.05.ConclusionsUnderstanding the pathway of IL-32 expression to stimulate the secretion cytokines via the activation of NF-κB and up-regulation of p-p38MAPK may or may not prove to be a therapeutic target, or a biomarker, and future studies will finally answer this hypothesis generated.     

Laminin isoforms in endothelial and perivascular basement membranes

Laminins, one of the major functional components of basement membranes, are found underlying endothelium, and encasing pericytes and smooth muscle cells in the vessel wall. Depending on the type of blood vessel (capillary, venule, postcapillary venule, vein or artery) and their maturation state, both the endothelial and mural cell phenotype vary, with associated changes in laminin isoform expression. Laminins containing the α4 and α5 chains are the major isoforms found in the vessel wall, with the added contribution of laminin α2 in larger vessels. We here summarize current data on the precise localization of these laminin isoforms and their receptors in the different layers of the vessel wall, and their potential contribution to vascular homeostasis.     

Anionic detergents as divalent cation ionophores across black lipid membranes

Summary Three ionic detergents commonly used in membrane-bound protein isolation and reconstitution experiments, SDS, cholate, and DOC, are shown to act as divalent cation ionophores when incorporated into black lipid membranes made from either oxidized cholesterol or a mixture of phosphatidylcholine and cholesterol (PC/cholesterol=51 mg). At a concentration greater than or equal to 1 m, SDS shows large selectivity differences between cations and anions and among the different cations tested (Ba²⁺, Ca²⁺, Sr²⁺, Mg²⁺, and Mn²⁺). Deoxycholate and cholate at concentrations greater than 4×10^–4 m and 10^–3 m, respectively, also act as divalent cation ionophores. The selectivity sequence measured for these two detergents is evidence for a strong ionic interaction between the divalent cation, and the anionic charged groups on the detergent. In the case of cholate, the conductance depends on the third or fourth power of the cholate concentration and shows a linear dependence on CaCl₂ concentration. The conductance for deoxycholate depends on the sixth or seventh power of the DOC concentration and is also linearly dependent on the CaCl₂ concentration. In an oxidized cholesterol black lipid membrane in the presence of 5mm CaCl₂, small concentrations of LaCl₃ (<1 m) inhibit the ionophoric activity of each of the detergents tested. Evidence is presented to show that this inhibitory effect is a nonspecific effect on oxidized cholesterol BLM's, and is not due to a direct effect of La³⁺ on detergent-mediated transport.