A comparison of simple analytical methods for determination of fluoride in microlitre-volume plasma samples

The aim was to compare potential methods for fluoride analysis in microlitre-volume plasma samples containing nano-gram amounts of fluoride. Methods: A group of 4 laboratories analysed a set of standardised biological samples as well as plasma to determine fluoride concentration using 3 methods. In Phase-1, fluoride analysis was carried out using the established hexamethyldisiloxane (HMDS)-diffusion method (1 mL-aliquot/analysis) to obtain preliminary measurement of agreement between the laboratories. In Phase-2, the laboratories analysed the same samples using a micro-diffusion method and known-addition technique with 200 µL-aliquot/analysis. Coefficients of Variation (CVs) and intra-class correlation coefficients (ICCs) were estimated using analysis of variance to evaluate the amount of variation within- and between-laboratories. Based on the results of the Phase-2 analysis, 20 human plasma samples were analysed and compared using the HMDS-diffusion method and known-addition technique in Phase-3. Results: Comparison of Phase-1 results showed no statistically significant difference among the laboratories for the overall data set. The mean between- and within-laboratory CVs and ICCs were < 0.13 and ≥0.99, respectively, indicating very low variability and excellent reliability. In Phase-2, the overall results for between-laboratory variability showed a poor CV (1.16) and ICC (0.44) for the micro-diffusion method, whereas with the known-addition technique the corresponding values were 0.49 and 0.83. Phase-3 results showed no statistically significant difference in fluoride concentrations of the plasma samples measured with HMDS-diffusion method and known- addition technique, with a mean (SE) difference of 0.002 (0.003) µg/mL. In conclusion, the known-addition technique could be a suitable alternative for the measurement of fluoride in plasma with microlitre-volume samples

An In Vitro Investigation of Anticaries Efficacy of Fluoride Varnishes

Most currently marketed fluoride varnishes (FVs) have not been evaluated for their effectiveness in preventing dental caries. The objective of this study was to investigate the anticaries efficacy, measured as fluoride release into artificial saliva (AS); change in surface microhardness of early enamel caries lesions; and enamel fluoride uptake (EFU) of 14 commercially available FVs and two control groups. Bovine enamel specimens (5×5 mm) were prepared and assigned to 18 groups (n=12). Early caries lesions were created in the specimens and characterized using Vickers microhardness (VHNlesion). FV was applied to each group of specimens. Immediately afterward, specimens were incubated in 4 mL of AS for 18 hours, which were collected and renewed every hour for the first six hours. AS samples were analyzed for fluoride using an ion-specific electrode. Specimens were then brushed for 20 seconds with toothpaste slurry and subjected to pH cycling consisting of a four-hour/day acid challenge and one-minute treatments with 1100 ppm F dentifrice for five days. Microhardness was measured following pH cycling (VHNpost). EFU was determined using microbiopsy. Acid resistance (eight-hour demin challenge) was performed after pH cycling, and microhardness was measured (VHNart) and compared with baseline values to test the FV impact after pH cycling. One-way analysis of variance was used for data analysis (α=0.05). FVs differed in their release characteristics (mean ± SD ranged from 14.97 ± 2.38 μg/mL to 0.50 ± 0.15 μg/mL), rehardening capability (mean ± SD ranged from 24.3 ± 15.1 to 11.7 ± 12.7), and ability to deliver fluoride to demineralized lesions (mean ± SD ranged from 3303 ± 789 μg/cm3 to 707 ± 238 μg/cm3). Statistically significant but weak linear associations were found between ΔVHN(post – lesion), EFU, and fluoride release (correlations 0.21-0.36). The results of this study demonstrated that differences in FV composition can affect their efficacy in in vitro conditions

In vitro Validation of Quantitative Light-Induced Fluorescence for the Diagnosis of Enamel Fluorosis in Permanent Teeth

This study aimed to validate quantitative light-induced fluorescence (QLF) as a diagnostic tool for mild and moderate enamel fluorosis in permanent teeth, comparing it to visual diagnosis and histological assessment completed using polarized light microscopy (PLM). The buccal surfaces of 139 teeth were visually classified using the Thylstrup and Fejerskov Index (TFI) into sound (TFI 0; n = 17), mild (TFI 1-2; n = 69), and moderate (TFI 3-4; n = 43) fluorosis. Fluorosis was then assessed with QLF (variables ΔF, A, and ΔQ at 5-, 15-, and 30-radiance thresholds) using as reference areas the entire surface and a region of interest (ROI), identified as the most representative region of a fluorosis lesion. PLM images of longitudinal thin sections including the ROI were assessed for histological changes. Correlations among TFI, PLM, and QLF were determined. A receiver-operating characteristic curve was conducted to determine QLF's diagnostic accuracy when compared to the TFI and PLM assessments. This was used to assess the probability that the images were correctly ranked according to severity as determined by PLM and TFI. A positive correlation was found between QLF and PLM, and between QLF and TFI. QLF showed the highest sensitivity and specificity for the diagnosis of mild fluorosis. There was also a strong agreement between TFI and PLM. The selection of a ROI resulted in a stronger correlation with TFI and PLM than when the entire surface was used. The study results indicate that defining an ROI for QLF assessments is a valid method for the diagnosis of mild and moderate enamel fluorosis

Presentación, clasificación y evolución de los pacientes con carcinoma hepatocelular en un centro de Veracruz, México

ResumenAntecedentesLa estadificación en el carcinoma hepatocelular (CHC) otorga pronóstico y orientación terapéutica. La resección y el trasplante hepático son opciones curativas y las terapias de ablación se aplican a pacientes que no reciben tratamiento curativo. La sobrevida tras la resección hepática o terapias de ablación es variada.ObjetivoDescribir la presentación, la estadificación, el manejo y la evolución de los pacientes con CHC en nuestro centro.Pacientes y métodosCuarenta y dos pacientes fueron seguidos prospectivamente durante 7 años. La sobrevida se calculó mediante Kaplan-Meier y log-rank entre los sistemas de estadificación (Okuda, BCLC y CLIP) y tipos de tratamiento (resección hepática, ablación por radiofrecuencia y ningún tratamiento quirúrgico).ResultadosLa edad media ± desviación estándar de los pacientes fue 68,9 ± 9,5 años; el 57% fueron mujeres y el 54% cirróticos. El 31% tenía infección por VHC. El tamaño medio del tumor fue 6.48 ± 2.52cm. Los estadios CLIP 0, Okuda I y BCLC A tuvieron mejor sobrevida que otros estadios (p<0.05). La resección tuvo mejor sobrevida (mediana: 32 meses y sobrevida a 1, 3 y 5 años del 83, el 39 y 19.7%) que ablación por radiofrecuencia (25 meses, y el 90 y el 17.2% a 1 y 3 años) y que ningún tratamiento quirúrgico (1 año<5%) (p<0.05).ConclusiónLos pacientes con CHC en nuestro centro al igual que otra población en México son diagnosticados tardíamente. El pronóstico usando CLIP y BCLC es similar a la literatura. Los mejores resultados se observaron en estadios tempranos y los que tuvieron resección quirúrgica del CHC.AbstractBackgroundHepatocellular carcinoma (HCC) staging provides a basis for calculating disease prognosis and therapeutic guidance. Liver resection and transplantation are curative options, and ablation therapies are applied to patients that are not candidates for curative treatment. Survival after liver resection or ablation therapies varies.AimsTo describe the presentation, staging, management, and outcome in patients with HCC in our center.Patients and methodsForty-two patients had a 7-year prospective follow-up. Survival was calculated with the Kaplan-Meier analysis and the log-rank test was used for its comparison between the staging systems (Okuda, BCLC, and CLIP) and types of treatment (liver resection, radiofrequency ablation, and no surgical treatment).ResultsThe mean age of the patients was 68.9 ± 9.5 years; 57% were women. A total of 54% of the patients presented with cirrhosis and 31% were infected with hepatitis C virus (HCV). The mean tumor size was 6.48 ± 2.52cm. The CLIP 0, Okuda I, and BCLC A stages had better survival rates than the other stages (P<0.05). Survival with resection was superior (median of 32 months and survival at 1, 3, and 5 years of 83, 39, and 19.7%, respectively) to that of both radiofrequency ablation (median of 25 months and survival at 1 and 3 years of 90 and 17.2%, respectively) and no surgical treatment (1 year < 5%) (P<0.05).ConclusionThe patients at our center were diagnosed at late stages of HCC, as is the case in other Mexican populations. Outcome in relation to CLIP and BCLC was similar to the prognoses reported in the literature. The best results were observed in the patients with early stage disease and those that underwent HCC resection surgery

Situación de la Varicela y del Herpes Zóster en España, 1998-2012

En España la vacuna de la varicela se introdujo en calendario de vacunación en 2005 para adolescentes susceptibles. Entre 2006 y 2008 Madrid, Navarra, Ceuta y Melilla incluyeron también la vacunación sistemática en la infancia. Además entre 2004 y 2014 la vacuna ha estado disponible en farmacias, con lo que en el resto de comunidades autónomas se ha vacunado a los niños fuera de las recomendaciones oficiales de vacunación. Para evaluar el impacto de la vacunación de varicela en la epidemiología de la varicela y del herpes zóster (HZ), se compara el periodo pre-vacunación (1998-2004) con el periodo post-vacunación (2006-2012) y, las comunidades autónomas que han introducido oficialmente la vacuna de varicela en la infancia con las que no la han introducido. Después de introducir la vacuna en calendario, la incidencia y las hospitalizaciones por varicela se han reducido, más en las comunidades que vacunan sistemáticamente en la infancia que en el resto (la incidencia se redujo un 16% y un 9% respectivamente y las hospitalizaciones un 64% y un 43% respectivamente). Las hospitalizaciones por HZ han aumentado en los mayores de 64 años, sobre todo en las regiones en las que más ha bajado la incidencia de varicela. Coberturas de vacunación entre el 20% y el 80% pueden retrasar la edad de presentación de la varicela, aumentando el riesgo de enfermedad grave y de mortalidad. Esta situación puede haberse reproducido en las comunidades autónomas en las que se ha vacunado a los niños fuera del calendario de vacunación y es previsible que, en mayor o menor medida, se incremente el porcentaje de adolescentes que cumplan los 12 años siendo susceptibles a varicela. Hay que fortalecer los programas de vacunación de varicela para asegurar que todos los adolescentes susceptibles reciban dos dosis de vacuna antes de llegar a la edad adulta. Además es preciso consolidar la vigilancia para monitorizar la evolución de la varicela y del HZ en los próximos años.N

Mars Science Laboratory Observations of the 2018/Mars Year 34 Global Dust Storm

Mars Science Laboratory Curiosity rover observations of the 2018/Mars year 34 global/planet-encircling dust storm represent the first in situ measurements of a global dust storm with dedicated meteorological sensors since the Viking Landers. The Mars Science Laboratory team planned and executed a science campaign lasting approximately 100 Martian sols to study the storm involving an enhanced cadence of environmental monitoring using the rover's meteorological sensors, cameras, and spectrometers. Mast Camera 880-nanometer optical depth reached 8.5, and Rover Environmental Monitoring Station measurements indicated a 97 percent reduction in incident total ultraviolet solar radiation at the surface, 30 degrees Kelvin reduction in diurnal range of air temperature, and an increase in the semidiurnal pressure tide amplitude to 40 pascals. No active dust-lifting sites were detected within Gale Crater, and global and local atmospheric dynamics were drastically altered during the storm. This work presents an overview of the mission's storm observations and initial results

Ringer's lactate improves liver recovery in a murine model of acetaminophen toxicity

<p>Abstract</p> <p>Background</p> <p>Acetaminophen (APAP) overdose induces massive hepatocyte necrosis. Liver regeneration is a vital process for survival after a toxic insult. Since hepatocytes are mostly in a quiescent state (G₀), the regeneration process requires the priming of hepatocytes by cytokines such as TNF-α and IL-6. Ringer's lactate solution (RLS) has been shown to increase serum TNF-α and IL-6 in patients and experimental animals; in addition, RLS also provides lactate, which can be used as an alternative metabolic fuel to meet the higher energy demand by liver regeneration. Therefore, we tested whether RLS therapy improves liver recovery after APAP overdose.</p> <p>Methods</p> <p>C57BL/6 male mice were intraperitoneally injected with a single dose of APAP (300 mg/kg dissolved in 1 mL sterile saline). Following 2 hrs of APAP challenge, the mice were given 1 mL RLS or Saline treatment every 12 hours for a total of 72 hours.</p> <p>Results</p> <p>72 hrs after APAP challenge, compared to saline-treated group, RLS treatment significantly lowered serum transaminases (ALT/AST) and improved liver recovery seen in histopathology. This beneficial effect was associated with increased hepatic tissue TNF-α concentration, enhanced hepatic NF-κB DNA binding and increased expression of cell cycle protein cyclin D1, three important factors in liver regeneration.</p> <p>Conclusion</p> <p>RLS improves liver recovery from APAP hepatotoxicity.</p

It's all about the children: a participant-driven photo-elicitation study of Mexican-origin mothers' food choices

Abstract Background There is a desperate need to address diet-related chronic diseases in Mexican-origin women, particularly for those in border region colonias (Mexican settlements) and other new destination communities in rural and non-rural areas of the U.S. Understanding the food choices of mothers, who lead food and health activities in their families, provides one way to improve health outcomes in Mexican-origin women and their children. This study used a visual method, participant-driven photo-elicitation, and grounded theory in a contextual study of food choices from the perspectives of Mexican-origin mothers. Methods Teams of trained promotoras (female community health workers from the area) collected all data in Spanish. Ten Mexican-origin mothers living in colonias in Hidalgo County, TX completed a creative photography assignment and an in-depth interview using their photographs as visual prompts and examples. English transcripts were coded inductively by hand, and initial observations emphasized the salience of mothers' food practices in their routine care-giving. This was explored further by coding transcripts in the qualitative data analysis software Atlas.ti. Results An inductive conceptual framework was created to provide context for understanding mothers' daily practices and their food practices in particular. Three themes emerged from the data: 1) a mother's primary orientation was toward her children; 2) leveraging resources to provide the best for her children; and 3) a mother's daily food practices kept her children happy, healthy, and well-fed. Results offer insight into the intricate meanings embedded in Mexican-origin mothers' routine food choices. Conclusions This paper provides a new perspective for understanding food choice through the eyes of mothers living in the colonias of South Texas -- one that emphasizes the importance of children in their routine food practices and the resilience of the mothers themselves. Additional research is needed to better understand mothers' perspectives and food practices with larger samples of women and among other socioeconomic groups

Association between neighborhood need and spatial access to food stores and fast food restaurants in neighborhoods of Colonias

Objective To determine the extent to which neighborhood needs (socioeconomic deprivation and vehicle availability) are associated with two criteria of food environment access: 1) distance to the nearest food store and fast food restaurant and 2) coverage (number) of food stores and fast food restaurants within a specified network distance of neighborhood areas of colonias, using ground-truthed methods. Methods Data included locational points for 315 food stores and 204 fast food restaurants, and neighborhood characteristics from the 2000 U.S. Census for the 197 census block group (CBG) study area. Neighborhood deprivation and vehicle availability were calculated for each CBG. Minimum distance was determined by calculating network distance from the population-weighted center of each CBG to the nearest supercenter, supermarket, grocery, convenience store, dollar store, mass merchandiser, and fast food restaurant. Coverage was determined by calculating the number of each type of food store and fast food restaurant within a network distance of 1, 3, and 5 miles of each population-weighted CBG center. Neighborhood need and access were examined using Spearman ranked correlations, spatial autocorrelation, and multivariate regression models that adjusted for population density. Results Overall, neighborhoods had best access to convenience stores, fast food restaurants, and dollar stores. After adjusting for population density, residents in neighborhoods with increased deprivation had to travel a significantly greater distance to the nearest supercenter or supermarket, grocery store, mass merchandiser, dollar store, and pharmacy for food items. The results were quite different for association of need with the number of stores within 1 mile. Deprivation was only associated with fast food restaurants; greater deprivation was associated with fewer fast food restaurants within 1 mile. CBG with greater lack of vehicle availability had slightly better access to more supercenters or supermarkets, grocery stores, or fast food restaurants. Increasing deprivation was associated with decreasing numbers of grocery stores, mass merchandisers, dollar stores, and fast food restaurants within 3 miles. Conclusion It is important to understand not only the distance that people must travel to the nearest store to make a purchase, but also how many shopping opportunities they have in order to compare price, quality, and selection. Future research should examine how spatial access to the food environment influences the utilization of food stores and fast food restaurants, and the strategies used by low-income families to obtain food for the household