OxyR Positively Influences Phaseolotoxin Synthesis and Pyoverdin Production in Pseudomonas savastanoi pv. phaseolicola NPS3121.

Phaseolotoxin is a major virulence factor of the bean pathogen bacterium P. savastanoi pv. phaseolicola. This toxin plays a key role in the development of the halo blight disease in bean plants. So far, the signal transduction pathways involved in the synthesis of phaseolotoxin have not been elucidated. The influence of regulation mechanisms related to the oxidative stress response, in particular the OxyR protein, it has been suggested to be involved in this process.. In this study we evaluated the role of OxyR in P. savastanoi pv. phaseolicola, mainly compared to the synthesis of phaseolotoxin and the virulence of this phytopathogen. Generation of the oxyR-mutant, pathogenicity and virulence tests, and analyses of gene expression by RT-PCR assays were performed. The results showed that OxyR exerts an effect on the synthesis of phaseolotoxin and positively influences the expression of the Pht and Pbo cluster genes. Likewise, OxyR influences the production of pyoverdine by the control of the expression of the genes encoding the PvdS sigma factor, involved in the synthesis of this pigment. This study is the first report on members of the OxyR regulon of P. savastanoi pv. phaseolicola NPS3121.

Antioxidant capacity and structural changes of human serum albumin from patients in advanced stages of diabetic nephropathy and the effect of the dialysis.

Changes in the antioxidant capacity of albumin and alterations of the albumin structural conformation were examined in patients in advanced stages of diabetes nephropathy. Human serum albumin was purified from diabetic patients in pre-dialysis (glomerular filtration rate [GFR] between 15 and 29 ml min(-1) 1.73 m(-2)) and those in dialysis (GFR ≤ 15 ml min(-1) 1.73 m(-2)) and then compared with albumin from patients with a normal GFR (>90 ml min(-1) m(-2)). We evaluated the antioxidant capacity of albumin using an enhanced chemiluminescence-based assay and thiol group content, and the structural changes were evaluated by circular dichroism and fluorescence spectroscopy. The antioxidant capacity and thiol content of albumin from patients in advanced stages of diabetic nephropathy were markedly reduced. The circular dichroism spectra showed a mean albumin α-helix content reduction from 44 to 37 % and from 44 to 30 % between the control group and pre-dialysis and dialysis patients, respectively. Additionally, the fluorescence intensity was reduced by 4.2 and 13 % for the groups 4 and 5, respectively, in relation with the control. These data provide evidence for the partial denaturation of albumin and exacerbated oxidative stress among patients in advanced stages of diabetes nephropathy before and even after dialysis.

Nicotinamide, a glucose-6-phosphate dehydrogenase non-competitive mixed inhibitor, modifies redox balance and lipid accumulation in 3T3-L1 cells.

AIMS: Excessive energy uptake of dietary carbohydrates results in their storage as fat and requires glucose-6-phosphate dehydrogenase (G6PD)-mediated NADPH production. We sought to assess whether the nicotinamide-induced reduction of G6PD activity might modulate redox balance and lipid accumulation in 3T3-L1 cells. MAIN METHODS: 3T3-L1 preadipocytes (days 4 and 6 of differentiation) and adipocytes were cultured in the presence of 5 or 25 mM glucose. The cells cultured in 25 mM glucose were supplemented with nicotinamide (5-15 mM). Next, we evaluated the following parameters: cell viability, apoptosis, lipid accumulation, lipolysis, reducing power, reactive oxygen species (ROS), NAD(P)H and NAD(P)(+), isocitrate dehydrogenase (IDP), malic enzyme and G6PD, as well as the protein and mRNA levels of G6PD. We also analysed the kinetics of the nicotinamide-induced inhibition of G6PD. KEY FINDINGS: G6PD mRNA levels increased at day 4 of adipocyte differentiation, whereas G6PD activity progressively increased at days 4 and 6 of differentiation and was reduced in adipocytes. Concomitantly, ROS, reducing power and lipid accumulation increased gradually as the preadipocytes matured into adipocytes. High glucose increased the activity of G6PD, which coincided with an increase in ROS, reducing power and lipid accumulation. All of these changes are prevented by nicotinamide, with the exception of lipid accumulation in adipocytes. Nicotinamide increased IDP activity without affecting NADPH levels. Lastly, nicotinamide inhibited G6PD in a non-competitive mixed way. SIGNIFICANCE: Nicotinamide modulates G6PD via a non-competitive mixed inhibition and decreases high glucose-dependent oxidative stress and lipid accumulation. Nicotinamide maintains NADPH levels by increasing the activity of IDP.

Técnica indireta com resinas compostas para uso direto em restauração de dentes posteriores: cimentação resinosa - Parte III / Indirect technique with composite resins for direct use in restorations of posterior teeth: luting resin (Part III)

A escolha do agente de cimentação ideal para restaurações indiretas depende do material restaurador utilizado, das propriedades e características dos agentes cimentantes e do preparo dentário. Porém, a preferência profissional é um fator determinante na escolha. Este artigo descreve o passo a passo da cimentação de restauração indireta em resina composta para uso direto

The choice of ideal cementing agent for indirect restorations depends on the restorative material, the properties and characteristics of cementing agents and dental preparation. However, the professional preference is a determining factor in choice. This article describes the step by step cementation of indirect restoration with composite resin for direct use

Tecnica indireta com resinas compostas para uso direto para restauraçao de dentes posteriores: estratificação, escultura dental e polimerização adicional (Parte II) / Indirect technique with composite resins for direct use in restorations of posterior teeth: stratification, dental sculpture and addition polymerization (Part II)

O desenvolvimento constante e evolução dos compósitos, juntamente das técnicas restauradoras em dentes posteriores, possibilitam melhores propriedades mecânicas e ópticas desses materiais, aumentando sua longevidade clínica. O emprego da polimerização adicional das resinas compostas realizado com calor, luz e pressão (ou associação dos métodos) resulta em melhores resultados na estabilidade dimensional, bem como da resistência diametral e à compressão. Este artigo descreve a técnica de estratificação e escultura dental em restauração de resina composta em dente posterior e destaca o uso e a importância da polimerização adicional

Constant development and evolution of the composites, along with restoration techniques in posterior teeth, allow better mechanical and optical properties of these materials, extending their clinic longevity. The usage of addition polymerization of the composite resins performed with heat, light and pressure (or a combination of these methods), presents better results for dimensional stability as well as for diametric resistance and compression. This work describes the technique of stratification and dental sculpture on composite resin restoration in posterior teeth, and highlights the use and the importance of addition polymerization

Técnica indireta com resinas compostas para uso direto para restauração de dentes posteriores: preparo dentário, moldagem e provisório - parte I / Indirect technique with composite resins for direct use in restorations of posterior teeth: dental preparation, molding and provisional - part I

A utilização de sistemas adesivos autocondicionantes de dois passos em restaurações de dentes posteriores e para o selamento imediato da dentina, garante melhores resultados na resistência de união dente-prótese, diminui a sensibilidade dentinária e protege o complexo dentino-pulpar. As resinas fluidas aplicadas para regularização e forramento da cavidade são essenciais para diminuir as tensões geradas pelo estresse de contração. A confecção de restauração provisória é essencial para manutenção funcional do dente e, consequentemente, proteção das estruturas envolvidas

The use of adhesive systems self-etching of two steps in posterior restorations and for the immediate dentin sealing, ensures better results in the bond strength of tooth-prosthesis, decrease the sensitivity of dentin and protect the pulp-dentin complex. The fluid resins applied for regularization and lining of the cavity are essential to reduce the tensions generated by the shrinkage stress. Making the provisional restoration is essential for functional maintenance of the tooth and, consequently, protection of the structures involved

Chemical and functional changes of human insulin by in vitro incubation with blood from diabetic patients in oxidative stress.

Oxidative stress damage to biomolecules has been implicated in several diseases including diabetes mellitus. In the present study, we investigated the effect of oxidative stress in whole blood (WB) from diabetic patients (n = 60) on recombinant human insulin. Insulin was incubated with WB obtained from diabetic patients (DP) who had hyperglycemia (>300 mg/dL) or from 41 healthy volunteers (HV). Whole blood of DP, unlike WB of HV, induced higher values of formazan (142%), dityrosines (279%), and carbonyls (58%) in the insulin residues. Interestingly, the insulin modified by WB of DP showed less hypoglycemic activity in rat (30%) in comparison with insulin incubated with WB of HV. The incubation of insulin in WB from DP induces chemical changes in insulin and a decrease in its biological activity, events that might be associated with the high levels of oxidative stress markers found in the plasma of these patients.

Determination of acrolein by high-voltage capillary electrophoresis from oxidized fatty acids.

Acrolein is an alpha,beta-unsaturated aldehyde with enormous capacity of reaction, occurs in the air like a pollutant, but it is (we know now) an important lipid peroxidation product as well. The compound is one of the several aldehydes produced from fatty acid oxidation, although it is particularly important because it constitutes the major electrophyle aldehyde derived from lipid oxidation. Acrolein can be formed actively from oxidized fatty acids and undergo aldolic condensation in alkaline pH; this is a particular characteristic that we have used in its process of separation with capillary electrophoresis. We have shown that the oxidation of unsaturated fatty acids forms acrolein, and that the use of capillary electrophoresis to be a powerful, sensitive, and attractive method for separation, identification, and quantization of this and other aldehydes from in vitro lipid peroxidation.

Formation of an adduct between insulin and the toxic lipoperoxidation product acrolein decreases both the hypoglycemic effect of the hormone in rat and glucose uptake in 3T3 adipocytes.

Lipid peroxidation induced by reactive oxygen species might modify circulating biomolecules because of the formation of alpha,beta-unsaturated or dicarbonylic aldehydes. In order to investigate the interaction between a lipoperoxidation product, acrolein, and a circulating protein, insulin, the acrolein-insulin adduct was obtained. To characterize the adduct, gel filtration chromatography, sodium dodecylsulfate-polyacrylamide gel electrophoresis and carbonyl determination were performed. Induction of hypoglycemia in the rat and stimulation of glucose uptake by 3T3 adipocytes were used to evaluate the biological efficiency of the adduct compared with that of native insulin (Mackness, B., Quarck, R., Verte, W., Mackness, M., and Holvoet, P. (2006) Arterioscler., Thromb. Vasc. Biol. 26, 1545-1550). Formation of the acrolein-insulin complex in vitro increased the carbonyl group concentration from 2.5 to 22.5 nmol/mg of protein, and it formed without intermolecular aggregates (Halliwell, B., and Whiteman, M. (2004) Br. J. Pharmacol. 142, 231-255. The hypoglycaemic effect 18 min after administration to the rat is decreased by 25% (Robertson, R. P. (2004) J. Biol. Chem. 279, 42351-42354. An adduct concentration of 94 nM, compared to 10 nM for native insulin, was required to obtain the A 50% (concentration needed to obtain 50% of maximum transport of glucose uptake by 3T3 adipocytes). In conclusion, formation of the acrolein-insulin adduct modifies the structure of insulin and decreases its hypoglycemic effect in rat and glucose uptake by 3T3 adipocytes. These results help explain how a toxic aldehyde prone to be produced in vivo can structurally modify insulin and change its biological action.

Oxidation by reactive oxygen species (ROS) alters the structure of human insulin and decreases the insulin-dependent D-glucose-C14 utilization by human adipose tissue.

The formation of dityrosine of human insulin oxidized by metal-catalyzed oxidation system (H2O2/Cu) was estimated by fluorescent methods. The oxidation of tyrosine and phenylalanine residues present on the insulin molecule was evident after 2 minutes of in vitro oxidation due to the formation of protein-bound dityrosine. The success of oxidative protein modification was followed until available aromatic residues were consumed (60 minutes), measured by their emission at 405 nm. The structural and chemical changes on insulin molecule are related to the loss of biological activity as assessed by measuring the increase of U-14C-glucose utilization by human adipose tissue in a radiorespirometry system. The oxidation of glucose (14CO2 production) of the adipose cells was increased 35 % (301 +/- 119 to 407 +/- 182 cpm/mg in dry weight. P < 0.05) in presence of 0.1 IU and 69 % (301 +/- 119 to 510 +/- 266 cpm/dry weight. P < 0.05) for 1.0 IU of insulin. The recombinant human insulin oxidized for 5 minutes only increased the glucose oxidation by 25 %. In conclusion, these observations show that dityrosine formation and other oxidative chemical changes of insulin due to its in vitro oxidation decrease and can abolish its biological activity.

Changes in human serum antioxidant capacity and peroxidation after four months of exposure to air pollutants

Twenty-one adult volunteers (aged 27-32 years), who had been living in Mexico City for four continuous months (physicians working as fellows) were studied the first and sixteenth week of their stay in order to learn the effect of the pollutants contained in Mexico City's atmosphere on some serum biochemical parameters. The activity of serum superoxide dismutase (SOD) decreased after 16 weeks in comparison with the values obtained the first week (109.6 to 56.9 mU/mg protein; 50 percent less). In contrast, the inhibitory capacity of serum vs. induced in vitro lipoperoxidation increased in relation to the length of stay (22 percent). The serum levels of thiobarbituric-reactive material also decreased in almost 30 percent (from 6.10 to 4.12 nmol). The other lipoperoxides measured were unchanged (chromolipids and diene conjugation). We propose that this may be as a result of the adaptive capacity of the human orgnaisms, within a pollutant atmosphere in which the ozone levels might participate in a decrease of SOD activity during chronic exposure, to air pollution

Possible effect of air pollutants (Mexico City) on superoxide dismutase activity and serum lipoperoxides in the human adult

The action of air pollutants, through their constituents, (O3, NO2, tobacco smoke) are capable of causing damage due to their lipoperoxidative properties or, indirectly, by inducing production of free radicals. As a consequence of photochemical processes, the ozone levels in the atmosphere of Mexico City are generally higher (mean of 0.325 ppm; period between 1987 - 1992) and may be harmful to health. Sixty two volunteers (medical doctors), aged 27-32 years, were divided into three groups. Group A was composed of those persons /17) who had never lived in Mexico City; a second group (B) (21) had recently arrived in Mexico City (1-8 days); and a third group (C) (24) who had permanently resided in mexico City. Serum was obtained from fresh whole blood. Superoxide dismutase (SOD) activity and thiobarbituric acid-reactive materials were higher in group B while chromolipids and the serum inhibitory capacity (for lipoperoxidation) was higher in group C. The acute exposure to pollutants in group B apparently may have induced SOD as an antioxidant defense and was responsible for the increased level of TBA reactive material. In group C, the significant finding is better antioxidative defenses and slightly higher chromolipids

Cocaína: aspectos clínicos, tratamiento y rehabilitación / Cocaine: treatment, rehabilitacion and clinical aspects

Estudia el problema del uso y abuso de la cocaína, analizando los aspectos epidemiológicos, clínicos, de tratamiento y de rehabilitación. Presenta al enfoque conductual-cognoscitivo como un muy eficaz instrumento teórico práctico para la comprensión de las diversas fases de la rehabilitación. Propone un programa conductal cognitivo para el tratamiento y rehabilitación de este tipo de pacientes

Uso del halo cefálico preoperatorio en las deformidades estructuradas de la columna vertebral / Pre-operative halo-traction in treatment of structural spinal deformities. Report of 32 cases

En el departamento de ortopedia del Hospital Universitario de Monterrey, N.L., México, desde enero de 1983 se han aplicado 32 halos cefálicos en pacientes con deformidades de la columna verteral. El objetivo de este trabajo es comentar la técnica empleada en la aplicación del halo; mencionar los casos en que se ha utilizado, así como dar a conocer el alto porcentaje de seguridad en su aplicación y la baja incidencia de complicaciones.

Instrumentación de Harrington con alambrado sublaminar total en escoliosis flexibles / Harrington instrumentation and sublaminar wiring for flexible scoliosis

De marzo de 1984 a noviembre de 1988 en el Servicio de Ortopedia del Hospital Universitario "Dr. José E. González" y del Hospital Regional del ISSSTE de Monterrey, Nuevo León, se trataron quirúrgicamente 25 pacientes con diagnóstico de escoliosis idiopática del adolescente y paralítica por poliomielitis que presentaban curvas torácicas o toracolumbares arriba de 40 grados, que dinámicamente corregían 50%o más. Se practicó instrumentación de Harrington más alambrado sublaminar total; el seguimiento mínimo fue de un año. No hubo complicaciones importantes. La corrección obtenida fue de 62%en promedio.

Sindrome de Eaton-Lambert / Eaton-Lambert's Syndrome

Se presenta un paciente de 63 anos con sindrome de Eaton-Lambert asociado a un carcinoma de celulas en avena en el pulmon. El paciente presentaba debilidad muscular proximal, ptosis palpebral izquierda que luego se hizo bilateral, cambio en el tono de la voz, dificultad para toser y para degluir alimentos. Los RX de torax mostraron una imagen densa en el tercio superior del pulmon derecho y la broncoscopia demostro una masa tumoral que ocluia totalmente la luz del bronquio superior y parcialmente del bronquio intermediario derecho. La EMG demostro la facilitacion post-ejercicio al estimulo repetitivo. Llamamos la atencion sobre este sindrome en pacientes mayores de 50 anos con sintomatologia de miastenia y sobre la necesidad de buscar un carcinoma broncogenico.