Polymeric Composites with Silver (I) Cyanoximates Inhibit Biofilm Formation of Gram-Positive and Gram-Negative Bacteria.

Biofilms are surface-associated microbial communities known for their increased resistance to antimicrobials and host factors. This resistance introduces a critical clinical challenge, particularly in cases associated with implants increasing the predisposition for bacterial infections. Preventing such infections requires the development of novel antimicrobials or compounds that enhance bactericidal effect of currently available antibiotics. We have synthesized and characterized twelve novel silver(I) cyanoximates designated as Ag(ACO), Ag(BCO), Ag(CCO), Ag(ECO), Ag(PiCO), Ag(PICO) (yellow and red polymorphs), Ag(BIHCO), Ag(BIMCO), Ag(BOCO), Ag(BTCO), Ag(MCO) and Ag(PiPCO). The compounds exhibit a remarkable resistance to high intensity visible light, UV radiation and heat and have poor solubility in water. All these compounds can be well incorporated into the light-curable acrylate polymeric composites that are currently used as dental fillers or adhesives of indwelling medical devices. A range of dry weight % from 0.5 to 5.0 of the compounds was tested in this study. To study the potential of these compounds in preventing planktonic and biofilm growth of bacteria, we selected two human pathogens (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and Gram-positive environmental isolate Bacillus aryabhattai. Both planktonic and biofilm growth was abolished completely in the presence of 0.5% to 5% of the compounds. The most efficient inhibition was shown by Ag(PiCO), Ag(BIHCO) and Ag(BTCO). The inhibition of biofilm growth by Ag(PiCO)-yellow was confirmed by scanning electron microscopy (SEM). Application of Ag(BTCO) and Ag(PiCO)-red in combination with tobramycin, the antibiotic commonly used to treat P. aeruginosa infections, showed a significant synergistic effect. Finally, the inhibitory effect lasted for at least 120 h in P. aeruginosa and 36 h in S. aureus and B. aryabhattai. Overall, several silver(I) cyanoximates complexes efficiently prevent biofilm development of both Gram-negative and Gram-positive bacteria and present a particularly significant potential for applications against P. aeruginosa infections.

PATHOGENETIC ADVANCES OF FOSINOPRIL SODIUM WITH HYDROCHLOROTHIAZIDE IN OBESE HYPERTENSIVE PATIENTS.

Purpose - to improve antihypertensive therapy on the basis of studying the antioxidant properties of an angiotensin-converting enzyme (ACE) inhibitor (fosinopril sodium) and a diuretic (hydrochlorothiazide), their impact on endothelial dysfunction and pro-inflammatory cytokines activity in hypertensive patients with overweight and obesity. A combination of fosinopril sodium 20 mg/day and hydrochlorothiazid 12.5 mg/day was prescribed to 54 patients with essential hypertension of 1-3 grades, 30 to 65 years old . The control group included 10 healthy subjects matched for age and sex. During the course of combined antihypertensive therapy we observed a significant decrease of i-NOS activity, reduce of TNF-α type I of its soluble receptor (sTNF-αRI), and 8-iso-PgF2α in the patients. Activity of e-NOS, superoxide dismutase and catalase, in contrast, were increased in patients with hypertension and concomitant obesity. Thus, the improvement of endothelial function, a significant decrease autoimmune activation due to lower tension of oxidative stress in the examined patients optimizes use of a combination of fosinopril sodium and hydrochlorothiazid for differentiated therapy in hypertensive patients with obesity.

[Endothelial immune activation and functional state in patients with hypertensive disease]. / Immunnaia aktivatsiia i funktsional'noe sostoianie éndoteliia u bol'nykh gipertonicheskoi bolezn'iu.

AIM: To investigate the nitric oxide (NO) system, the activity of endothelial NO synthase (e-NOS) and inducible NO synthase (i-NOS) in relation to the levels of tumor necrosis factor-α (TNF- α) and its soluble receptor type I (sTNFRI) depending on the grade of hypertensive disease (HD). SUBJECTS AND METHODS: A total of 317 patients, including 284 patients aged 30 to 65 years (mean age 54.7±0.58 years) with Grades 1-3 HD who had not previously received regular antihypertensive therapy and 33 apparently healthy individuals, were examined at Kharkov City Clinical Hospital Eleven. Immune activation was judged by the serum levels of the proinflammatory cytokine TNF-α in all the examinees and y those of sTNFRI, which were measured by enzyme immunoassay. To study the endothelial functional state, the level of stable end metabolites of nitric oxide, that of S-nitrosothiol and the activity of NO synthases were biochemically determined in 100 patients from this group. A control group consisted of 16 apparently healthy individuals. RESULTS: There were increases in the circulating levels of proinflammatory cytokines (TNF-α, sTNFRI), the content of S-nitrosothiol and the activity of i-NOS. At the same time, there were decreases in the activity of e-NOS and the level of end nitric oxide metabolites, such as nitrites and nitrates. CONCLUSION: In patients with HD, the end metabolites of nitric oxide decrease, which indirectly shows a reduction in its vasoactive part, and the stable NO metabolite S-nitrosothiol increases. This is associated with enhanced NO oxidation under conditions of oxidative stress and endothelial dysfunction. The higher amount of S-nitrosothiol in the examinees may be associated with increased i-NOS. The immunoinflammatory activation mediated by the proinflammatory cytokines, particularly by the enhanced activity of TNF-α and sTNFRI, has been proven to play a role.

Redox cycling by motexafin gadolinium enhances cellular response to ionizing radiation by forming reactive oxygen species.

PURPOSE: To examine the mechanism of radiation enhancement by motexafin gadolinium (Gd-Tex) in vitro. METHODS AND MATERIALS: Oxidation of ascorbate and NADPH by Gd-Tex was evaluated in a neutral buffer. Growth inhibition of human uterine cancer cell line MES-SA was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye. Clonogenic assays were used to measure radiation response in MES-SA, A549 human lung carcinoma, E89, a CHO cell line variant deficient in glucose-6-phosphate dehydrogenase activity, and murine lymphoma cell lines LYAR and LYAS. RESULTS: Gd-Tex catalyzed the oxidation of NADPH and ascorbate under aerobic conditions, forming hydrogen peroxide. Decreased viability was observed in MES-SA cells incubated with Gd-Tex in media containing NADPH or ascorbate. Gd-Tex and ascorbate increased fluorescence in dichlorofluorescin acetate-treated cultures. Synergistic effects on the aerobic radiation response in MES-SA and A549 were seen using Gd-Tex in combination with L-buthionine-(S,R)-sulfoximine (BSO). Incubation with Gd-Tex in the presence of ascorbate increased the aerobic radiation response of E89 and the apoptosis-sensitive B-cell line (LYAS). CONCLUSIONS: Gd-Tex sensitizes cells to ionizing radiation by increasing oxidative stress as a consequence of futile redox cycling. Optimization of the concentration of ascorbate (or other reducing species) may be required when evaluating Gd-Tex activity in vitro.

Synthesis of a metal-free texaphyrin.

The synthesis of a metal-free form of texaphyrin, an aromatic porphyrin-like macrocycle, is described. Previously, texaphyrins could only be obtained reproducibly in the form of metal complexes. Using ferrocenium cation as the oxidizing agent and starting with a reduced porphyrinogen-like nonaromatic form of texaphyrin, we isolated, in good yield, the metal-free oxidized texaphyrin as its HPF(6) salt. This product was characterized by X-ray diffraction analysis, UV-vis spectroscopy, and cyclic voltammetry. [structure: see text]

Organoantimony(V) cyanoximates: synthesis, spectra and crystal structures.

A series of 25 new organoantimony(V) cyanoximates has been synthesized and studied using IR, visible, and NMR spectroscopy and X-ray analysis. Crystal structures were determined for compounds (C6H5)4Sb[ONC(CN)C(O)NH2] (1) and (C6H5)4Sb[ONC(CN)C(O)N(CH3)2] (2). Both complexes crystallized in the monoclinic space group P2(1)/c (Z = 4) with unit cell parameters (A, grad) of a = 14.921(3), b = 10.165(2), c = 17.571(7), beta = 113.26(6) for compound 1, and a = 16.415(4), b = 10.406(3), c = 17.152(3), beta = 17.152(3), beta = 117.79(2) for compound 2. For 5438 and 5056 independent reflections the refinement yielded R-factors 0.022 and 0.037 for the structures of 1 and 2, respectively. Cyanoxime anions are bound to the antimony(V) atoms in a monodentate fashion via the oxygen atoms of the oxime groups. The ligands adopt trans-anti configuration in these compounds. The coordination polyhedron in both complexes is a distorted trigonal bipyramid with the axial location of the cyanoxime ligand. A similar binding mode of other anions in synthesized organoantimony(V) complexes has been offered on the basis of the similarity of their IR spectra to those of the compounds whose structures were determined crystallographically. The exact assignment of vibrations involving the oxime group was carried out using synthesized 15N(53%), isotopomers.