Juan Francisco Hernández-Sierra

The antimicrobial sensitivity of Streptococcus mutans to nanoparticles of silver, zinc oxide, and gold.

Dental caries is a worldwide public health problem for which Streptococcus mutans has been identified as the possible infectious etiology. In recent years nanotechnology has permitted the development of new properties of materials. The objective of this study was to compare the bactericidal and bacteriostatic effects of nanoparticles of silver, zinc oxide, and gold on S. mutans. We used the liquid dilution method to find the minimum inhibitory concentrations (MICs) and with subcultures obtained the minimum bactericidal concentrations (MBCs). For silver the results showed an average MIC of 4.86 +/- 2.71 microg/mL and MBC of 6.25 microg/mL; for zinc the MIC was 500 +/- 306.18 muicrog/mL and MBC of 500 microg/mL; the gold nanoparticles demonstrated an effect only at an initial concentration of 197 mug/mL. We established a higher antimicrobial effect against S. mutans of silver nanoparticles at lower concentrations than gold or zinc, which would allow achieving important clinical effects with a reduced toxicity.

Fluorosis en dentición temporal en un área con hidrofluorosis endémica

OBJETIVO: Determinar la prevalencia de fluorosis dental en la poblacion infantil de la ciudad de San Luis Potosi, y su asociacion con la concentracion de fluor en agua de consumo y de orina. Asimismo, desarrollar, validar y probar un indice especifico para fluorosis en denticion temporal. MATERIAL Y METODOS: Se efectuo un estudio transversal analitico, de mayo de 1997 a enero de 1999, en tres jardines de ninos, seleccionados al azar, en tres areas de riesgo en San Luis Potosi. Se seleccionaron 100 ninos de edades entre tres y seis anos. El indice especifico de fluorosis para dientes temporales fue validado mediante la cuantificacion de concentraciones de fluor en esmalte de dientes con y sin fluorosis. Para estimar la asociacion entre las concentraciones de fluor en agua y orina y el grado de fluorosis dental se utilizo la prueba estadistica Kruskal-Wallis. En el caso de la asociacion entre el area de riesgo y el desarrollo de fluorosis dental se utilizo ji2 de Mantel-Haenszel. RESULTADOS: La prevalencia de fluorosis en denticion temporal fue de 78%, la cual tuvo patrones diferentes de presentacion, siendo los dientes posteriores los mas afectados en ambos maxilares y la coloracion predominante fue blanco mate. Se encontro una correlacion (r=0.93) entre la concentracion de fluor en esmalte de dientes temporales y el indice de fluorosis para denticion temporal (IFDDT). Se encontraron asociaciones entre la concentracion de fluor en el agua de consumo y orina con el grado de fluorosis dental (Kruskal-Wallis, p=0.00001) y entre el area de riesgo y el grado de fluorosis (ji² de Mantel-Haenszel p=0.00001). CONCLUSIONES: El IFDDT identifica y gradua adecuadamente la fluorosis en denticion temporal. Es importante detectar el primer efecto toxico de exposicion a fluor para ser usado como predictor de fluorosis en denticion permanente y fluorosis esqueletica.

Análisis de factores asociados al fracaso del tratamiento médico del absceso hepático amebiano

INTRODUCTION To identify the laboratory and ultrasound factors that could predict the response to medical treatment of amoebic liver abscess. MATERIAL AND METHOD Retrospective study of patients diagnosis with amoebic liver abscess in Hospital Central in San Luis Potosí, Mexico. We included patients greater than 15 years of both sexes. We excluded those with probable pyogenic abscess, immunosupression, history of abdominal or biliary surgery, abdominal neoplasm abdominal or sepsis. We identified patients with good response to medical treatment and patients who needed the abscess drained. We studied the ultrasound findings, plasma levels of albumin, alkaline phosphatase and bilirubin. RESULTS We analysed 45 patients, 31 had a good response (controls) and 14 needed drainage (cases). The medians of the variables with statistical significance in bivariate analysis were: albumin 2.65 g/dl and 1.7 g/dl (p < 0.001); alkaline phosphatase 133 U and 259 U (p = 0.02) and diameter of absences 5.9 cm and 9.95 cm (p < 0.001), controls and cases respectively. By logistic regression the diameter of the abscess showed a determination coefficient of 0.447 (p < 0.05) and OR = 14.85 (95% CI, 2.11-104.9) for drain if it was > or = 8 cm. CONCLUSIONS A diameter bigger than 8 cm in hepatic amoebic abscess is associated with failure of medical treatment. Low albumin could be related to malnutrition and increased alkaline phosphatase with extrinsic compression of extrahepatic conducts due to big abscesses.Resumen Introduccion Identificar los factores de laboratorio y ultrasonograficos que pudieran predecir la respuesta al tratamiento medico del absceso hepatico amebiano. Material y metodo Se realizo un estudio retrospectivo de pacientes con diagnostico de absceso hepatico amebiano en el Hospital Central de San Luis Potosi, Mexico. Se incluyo a los pacientes mayores de 15 anos de ambos sexos. Se excluyo a los sujetos con sospecha clinica de absceso piogeno, inmunosupresion o con antecedentes de cirugia abdominal o biliar o neoplasia abdominal. Se identifico a los pacientes que respondieron favorablemente al tratamiento medico y aquellos que requirieron de intervencion para el drenaje del absceso. Se estudiaron los hallazgos ultrasonograficos, concentraciones sericas de albumina, fosfatasa alcalina y bilirrubinas. Resultados Se analizo a 45 pacientes, 31 respondieron al tratamiento (controles) y 14 requirieron intervencion (casos). Las medianas de las variables con significacion estadistica en el analisis bivariable fueron: concentraciones de albumina de 2,65 y 1,7 g/dl (p Conclusiones Un diametro > 8 cm del absceso hepatico amebiano se relaciono con fracaso del tratamiento medico. La asociacion con hipoalbuminemia probablemente se relaciona con desnutricion, mientras que valores elevados de fosfatasa alcalina pueden deberse a compresion extrinseca de los conductos extrahepaticos por abscesos de gran tamano.

Prognostic indications of the failure to treat amoebic liver abscesses

Abstract Objectives: To identify the variables that predict the failure to treat amoebic liver abscesses. Methods: We prospectively carried out a case–control study on a cohort of patients who had been diagnosed with amoebic liver abscesses using clinical, ultrasonic, and serologic methods. Patients with pyogenic abscesses, negative ELISA tests for amoebiasis, immunosuppression status, or previous abdominal surgery were excluded. All patients received metronidazole, and those who demonstrated 4 days of unfavorable clinical responses received percutaneous or surgical draining of the abscess. Demographic, laboratory, and ultrasonographic characteristics were assessed as prognostic indications of failure. Results: Of 40 patients with amoebic liver abscess, 24 (mean age: 36·7±11·2 years) responded to medical treatment and 16 (41·8±11·6 years) required drainage, including 14 patients who underwent percutaneous drainage and two patients who required surgery. The albumin level, abscess volume, abscess diameter, and alkaline phosphatase level were all statistically significant (P<0·05) on the bivariate analysis. The highest (>99%) sensitivity and negative predictive value were observed for an abscess volume >500 ml and diameter >10 cm, while the best specificity and positive predictive value were achieved with the combination of low serum albumin level, high alkaline phosphatase level, and large abscess volume or diameter. Conclusions: The prognostic indications of the failure to treat amoebic liver abscesses include low albumin, high alkaline phosphatase, and large abscess volume or diameter. The combination of these variables is a useful and easy tool for determining appropriate therapy.

Amoebic toxic colitis: analysis of factors related to mortality

Abstract Background: Toxic or fulminant colitis due to Entamoeba histolytica infrequently presents but is very serious. Unfortunately, there are numerous contradictory factors related to mortality. Methods: We analyzed several cases of E. histolytica infection to determine the factors related to mortality. We included patients >15 years of age who were histopathologically diagnosed with amoebic toxic colitis and treated from January 2000 through December 2006. We evaluated demographic, clinical, laboratorial, surgical, and histopathological characteristics. Results: We examined 24 patients and recorded 12 deaths (50%). Twenty patients underwent surgery within a mean time of 24 hours (range: 8–120 hours). Tenesmus and intestinal perforation were determined to be statistically significant (P<0·05) by univariate analysis. Three models of logistic regression were able to determine three statistically significant factors that affected mortality: (1) tenesmus and a lymphocyte count <1·5×103 cell/μl; 2) depth of invasion beyond the mucosa and a lymphocyte count <1·5×103 cell/μl; 3) time spent with symptoms and perforation. Conclusions: The mortality rate determined in this study is similar to previously reported series. A low lymphocyte count, significant depth of invasion, and intestinal perforation were determined to be the factors related to increased mortality, while tenesmus and limited amount of time spent with symptoms were associated with survival. Quick diagnosis and appropriate treatment are important factors that reduce mortality.

Feasibility for Non Invasive Estimation of Glucose Concentration in Newborns Using NIR Spectroscopy and PLS

We report the preliminary results obtained for estimation of glucose concentration in newborns using near infrared spectroscopy (NIR) and a prediction model calibrate for an adult using multivariate analysis techniques, in a concentration range between 30 to 100 mg/dL. In addition we compared the results of prediction by PLS and the two commercial glucometers used for a rapid monitoring in neonates against the clinic standard.

Effect of Silver Nanoparticle-Added Pit and Fissure Sealant in the Prevention of Dental Caries in Children

OBJECTIVE The objective of this study was to evaluate the effects of pit and fissure sealant mixed with silver nanoparticles on dental caries, by means of monthly measurement of fluorescence with DIAGNOdent over six months. STUDY DESIGN This study was divided in two phases: experimental and clinical. In the experimental phase, the adhesion and microleakage of the pit and fissure sealant experiment were evaluated. Two groups of 10 teeth, without serious carious lesions, were included. Conventional (group A) and silver nanoparticles (group B) were added to the pit and fissure sealant. For the clinical phase, a split-mouth study was performed on 40 children aged 6-10 years old with healthy, erupted permanent first molars. A conventional pit and fissure sealant or a silver nanoparticle-mixed sealant was randomly placed. Repeated measures analysis was performed. RESULTS Conventional sealant presented an average microleakage of 30.6%, and the silver nanoparticle-mixed sealant showed 33.6% (P=NS). A three times greater reduction in fluorescence was found in the silver nanoparticles group compared to the conventional group (P<0.05). No sex- or age-based associations were found. CONCLUSIONS The silver nanoparticle-mixed sealant reduced tooth demineralization significantly and likely increased remineralization, compared to the conventional sealant.

Eficacia de la auriculoterapia modificada como tratamiento para el control del dolor postoperatorio en pacientes intervenidos mediante colecistectomía laparoscópica

BACKGROUND The high frequency of post-operative pain in the patients after laparoscopic cholecystectomy has led to the need to use multiple analgesic therapies. These include auriculotherapy, although not very good results have been obtained with the traditional techniques. OBJECTIVE To evaluate the effectiveness of modified auriculotherapy for post-operative pain control in laparoscopic cholecystectomy patients. MATERIAL AND METHODS Double-blind controlled clinical trial. Experimental group: Different points ear puncture with xylocaine without needles vs. placebo group. Post-operative visual analogue scale (VAS) at 6, 12, 18, 24, 36, and 48h and rescue doses of analgesics, were measured in both groups. RESULTS At 6h post-operative, 87% of the auriculotherapy group had a VAS of<4 vs. 48% of placebo group (p = 0.004), and 96 vs. 74% (p = 0.008) at 18hours. At 24, 36 and 48h after surgery there were no differences, and as all of the patients in both groups had a VAS<4, they were discharged to the hospital. CONCLUSIONS Modified auriculotherapy was better to the conventional analgesics for post-operative pain control in patients subjected to laparoscopic cholecystectomy.