Two mechanisms of oral malodor inhibition by zinc ions

Abstract Objectives The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. Material and Methods The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Results Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Conclusions Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria.

Relación entre los niveles de compuestos volátiles sulfurados con los niveles de RANKL y OPG en pacientes con periodontitis crónica moderada o severa: estudio transversal / Relationship between the levels of volatile sulfur compounds with the levels of RANKL and OPG in patients with moderate or severe periodontitis: A cross sectional study

Antecedentes: El efecto de los Compuestos Volátiles Sulfurados (CVS) sobre los tejidos periodontales, específicamente a nivel del eje RANKL/OPG, no ha sido dilucidado y en la actualidad existe escasa literatura al respecto publicada. Objetivo: Evaluar si los CVS medidos en la cavidad oral de pacientes con periodontitis crónica moderada a severa se relacionan con la expresión de RANKL y OPG a nivel de fluido gingival crevicular (FGC). Método: Se realizó un estudio transversal con 71 pacientes derivados de la Unidad de Diagnóstico de la Clínica Odontológica Docente Asistencial de la Universidad de los Andes. Posterior a la realización de un examen periodontal completo se tomaron muestra de los niveles de CVS de la boca de los pacientes mediante un monitor de sulfuros y muestras de FGC para evaluar los niveles de RANKL y OPG mediante test de ELISA. Los datos obtenidos fueron analizados mediante test de correlación de Spearman. Resultados: Al evaluar la correlación de los niveles de CVS con los niveles de RANKL, OPG y la razón RANKL/OPG, se observó un R de 0.098 con un p value = 0.41; -0.084 con un p value= 0.48 y 0.067 con un p value = 0.57 respectivamente. Conclusiones: El presente estudio no pudo demostrar si existe una relación entre los niveles de CVS con la expresión de RANKL y OPG en el FGC de pacientes con periodontitis crónica.

Background: The effect of the Volatile Sulfur Compounds (VSC) on the periodontal tissues, specifically at the RANKL/OPG level has not been elucidate and there is little literature published on this subject. Aim: To explore if the VSC levels measured in the oral cavity of patients with moderate or severe chronic periodontitis are correlated with the expression of RANKL and OPG at the gingival fluid level (GF). Method: A cross-sectional study was conducted with 71 patients referred by the Universidad de los Andes’s dentistry diagnosis department. After undergoing full-mouth periodontal exam, levels of CVS were recorded using a sulfur monitor and then GF was extracted to assess RANKL and OPG levels with ELISA. Data was analyzed with Spearman correlation test. Results: The correlation (R) between the VSC and the GF levels was 0.098 with a p value = 0.41; -0.084 with a p value = 0.48 y 0.067 with a p value = 0.57 respectively. Conclusions: This study could not demonstrate if there is a relation between the VSC levels and the expression of RANKL and OPG in the GF in patients with chronic periodontitis.

Aislamiento y cultivo de bacterias sulfato reductoras acidófilas para la Producción de Sulfuro Biogénico para la precipitación de metales pesados / Isolation and culture of bacteria `sulfate` reducing acidophil for the Production of Sulfide Biogenic for the precipitation of heavy metals

Los drenajes ácidos de mina (DAM) están caracterizados por acidez extrema y altas concentraciones de metales pesados y sulfatos. Las bacterias sulfato reductoras (BSR) reducen sulfatos oxidandola materia orgánica para la producción de sulfuro de hidrógeno y bicarbonato. la biorremediación consiste en la precipitación insoluble del sulfuro con los metales pesados y la alcalinización del medio por el bicarbonato.

Estimation of hydrogen sulphide in the human lymphocytes.

Hydrogen sulphide (H2S), a signaling gasotransmitter and a potent vasorelaxant is endogenously produced by the enzymes cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE). CBS is a predominant source of H2S in the central nervous system, while CSE is the major H2S producing enzyme in the brain and other nervous tissues. Though the expression of these enzymes in the blood lymphocytes is known, H2S formation in the lymphocytes has not been reported so far. In the present study, H2S levels in the lymphocytes of healthy control subjects were estimated, after suitable modifications in a routine method [Stipanuk M H & Beck P W (1982) Biochem J 206, 267-277] used for detecting tissue levels of H2S. In this method, homocysteine (Hcys) due to its higher solubility was used as the substrate in place of L-cysteine and NaOH was used in place of zinc acetate to increase the entrapment of H2S in the central well. A mean H2S level of 11.64 +/- 6.36 microM/min/mg protein was detected in the lymphocytes of 8 subjects (mean age, 24 +/- 2; 2 male, 6 female). The modified method was found to be more sensitive for H2S estimation in human lymphocytes. As endogenous H2S is reported to be involved in the pathogenesis of various cardiovascular and pulmonary diseases, the levels of H2S in lymphocytes can be a marker of the endogenous tissue levels.

A study on physicochemical parameters of an aquaculture body in Mysore city, Karnataka, India.

Monthly changes in water quality parameters (physicochemical) of a rain fed lake (Bilikere) in Mysore city, were investigated for two calendar years (2002 and 2003) to assess the suitability of this lake for pisciculture. Although there were monthly fluctuations in water temperature, total suspended solids (TSS), dissolved oxygen (DO), nitrite and ammonia, they were within the desirable limits. On the other hand, total alkalinity and hydrogen sulphide throughout the study period and pH for a major part, were higher than the desirable limits. Other parameters viz; turbidity, biological oxygen demand (BOD), phosphate, and nitrate in a few months were higher than the desirable limits for waters used for fish culture. The high levels of these factors are due to the entry of agricultural run off and occasional flow of sewage into the lake. In addition dense algal growth was noticed at times of the year which is caused by surge in nutrients level whenever there was a rainfall. Since, the lake has a great aquacultural potential, it is suggested that control of nutrient load that enters the lake occasionally, might help the lake to continue its mesotrophic status.

Producción biogénica de Sulfuro deHidrógeno a partir de material celulósicoy xilanósico / Biogénica production of xilanósico sulfide de hidrógeno based on material celulósicoy

Las Bacterias Sulfato Reductoras (BSR) son responsables de la producción de sulfuro de hidrógeno (H2S) en anaerobiosis a partir de sulfatos y un donador de electrones. El sulfuro producido podría utilizarse para precipitar metales catiónicos divalentes,permitiendo la biorremediación de efluentes contaminados. El presente estudio forma parte del proyecto: “Biodiversidad Microbiana del programa UMSA-SAREC” con cooperación del departamento deBiotecnología de la Universidad de Lund y establece la posibilidad de montar biorreactores en el altiplano Boliviano para generar H2S. En el trabajo, se”utilizó paja de trigo (donador de electrones) y consorcio bacteriano A10 (BSR) obtenido de la laguna ChalviriPotosí. Bajo condiciones de cultivo batch, se obtuvo una concentración de H2S entre 5 y 8 mM, y en condiciones de cultivo continuo una concentración de25 mM a los 100 días, concentraciones similares se sostuvieron por 90 días, lo que hace este modelo prometedor para su aprovechamiento a escala industrial.

Desarrollo y validación de laboratorio de un dosimetro pasivo de tira reactiva para sulfuro de hidrogeno / Laboratory development and validation of a passive reactive strip dosimeter for sulfur hydrogen

Se describe la elaboración, calibración y validación de laboratorio de un dosímetro pasivo de tira reactiva para la determinación de la concentración de sulfuro de hidrógeno en el aire. El dosímetro es válido para determinar concentraciones del orden de 10 a 100 mg/m3 (0,5 a 5 CMA) y tiempos de exposición de 15 min a 1,5 h. El error total de la determinación es de más o menos 15,2 por ciento . El método es sencillo y no requiere de análisis posterior en un laboratorio