The Effect of Coloring Beverages on Color Stability of Hybrid Ceramics with Different Surface Treatments

ABSTRACT Objective To assess the effects of coloring beverages on the color stability of two types of hybrid ceramics with different surface treatments. Material and Methods 180 specimens of two hybrid ceramics (Vita Enamic and Mazic Duro) and a feldspathic ceramic (Vita Mark II) were prepared (n=60 in each group). Half of the discs in each group were glazed while the other was polished. The specimens were then divided into three subgroups and immersed in distilled water, carrot juice, and coffee. The overall color difference (∆E) was calculated based on CIE L*a*b* color space. Data were analyzed using three-way and one-way ANOVA; Tukey's honest significant difference was also done for pairwise comparisons (α=0.05). Results Vita Mark II specimens revealed less overall color changes compared to other groups. The ∆E of the glazed Vita Enamic specimens was greater than polished specimens following immersion in distilled water (p=0.03) and coffee (p=0.001), but it was not significant for carrot juice. The same results were obtained for polished Mazic Duro specimens. Relatively similar amounts of ∆E were recorded in polished and glazed subgroups of Vita Mark II. Conclusion The ∆E of hybrid ceramics was higher than Vita Mark II. Polishing could be recommended for surface treatment of hybrid ceramics instead of glazing, saving time and facilitating the process.

Spectrophotometric Analysis of Streptococcus mutans Growth and Biofilm Formation in Saliva and Histatin-5 Relate to pH and Viscosity

ABSTRACT Objective: To analyze the ability of saliva in controlling the growth and the biofilm formation of Streptococcus mutans (S. mutans) as well as the effect of histatin-5 anti-biofilm relate to pH and saliva viscosity. Material and Methods: The S. mutans biofilm assayed by crystal violet 1% and its growth measured by spectrophotometer. The saliva viscosity was analyzed by viscometer, and pH of saliva was measured by pH meter. Results: Based on the optical density values, growth of S. mutans in saliva ranged <300 CFU/mL (0.1 nm) at concentrations of 25%, 12.5% and 6.25% for 24 hours. Whereas at the 48 h and 72 h period of incubation shown an increase in growth of S. mutans ranged 300-600 CFU/mL (0.2-0.36 nm). The inhibitory biofilm formation of S. mutans in saliva was significantly higher at concentrations of 12.5% and 6.25% at 24 h incubation times on a moderate scale, whereas the histatin-5 was effective to inhibit S. mutans biofilm on the 50 and 25 ppm. The saliva possessed a higher inhibitory of biofilm S. mutans than histatin-5 and good level viscosity (0.91-0.92 cP). Conclusion: The saliva was able to control the growth of S. mutans, and histatin-5 can inhibit the biofilm formation S. mutans. Furthermore, the saliva was also able to respond to the pH change with good viscosity of saliva.

Analysis of the qPCR Assay Efficacy as Molecular Diagnostic in Patients with Chemotherapy and/or Antibiotic Therapy

Abstract High sensitivity of qPCR assay can be compromised by the presence of PCR inhibitors in samples analyzed. The aim of this study was to analyze the RT-qPCR assay efficiency considering the RNA quality/quantity and the presence of PCR inhibitors in patients with chemotherapy and/or antibiotic therapy. We analyzed 60 samples using RT-qPCR from individuals suspected of leukemia and 44 samples were quantified by fluorimetry and spectrophotometry. The efficiency of the RT-qPCR assay was evaluated comparing the threshold cycle (Ct) from tested samples and the standard curve. The 260/280 and 260/230 ratios, the presence of PCR inhibitors and the amount of sample (ng) used in the RT-qPCR reaction can be associated with 56.8% (R²=0.56, p<0.05) in the Ct obtained. The decrease of the RT-qPCR efficiency can be explained in 42,8% due to the variation of the 260/280 ratio (R²=0.42,p<0.05). The presence of antibiotics in the blood sample can be associated in 11.3% with the variability of 260/280 ratio (R²=0.11,p<0.05). Presence of chemotherapeutic drugs in the blood sample was not correlated with Ct variation (p=0.17). The spectrophotometer determines a RNA quantification with 2.2 times higher than the fluorimeter (t=2.2, p=0,03) and this difference is correlated with the 260/280 ratio (R²=0.36, p<0.05). Samples with low purity had a reduction in the qPCR efficiency, although we did not observe false results.

Evaluation of Sample Preparation Procedures for Determination of Cr(VI) in Cr2O3 Pigments by Vis Spectrophotometry

Abstract Six sample preparation procedures were evaluated for selective extraction of Cr(VI) from commercial samples of chromium oxide green (Cr2O3) pigments prior to formation of its diphenylcarbazone complex [CrDPCO]- for determination by visible spectrophotometry: (I) water-soluble chromium; (II) EPA method 3060A without Mg2+; (III) EPA method 3060A with Mg2+; (IV) Na3PO4 based extraction; (V) method IRSA16 based on acidic extraction and; (VI) Na2CO3 based extraction. Evaluation of the influence of concomitant Cr(III) ions, time and stability of the [CrDPCO]- complex was investigated. Recoveries of soluble and insoluble Cr(VI) species were 86% and 80%, respectively, using procedure (VI). Direct calibration against aqueous standards prepared in the extraction medium was successful for Cr(VI) in the concentration range 0.05-1.50 μg L-1. Limits of detection and quantitation were 0.3 µg g-1 and 1.0 µg g-1, respectively, for 250 mg subsamples/25 mL. Procedure (VI) was applied to the analysis of four commercial samples of Cr2O3 pigments, three determined to have Cr(VI) within compliance limits below 1.0 µg g-1, but one at 16.6 ± 0.6 µg g-1, prohibiting use of this pigment in cosmetic formulations. This sample was conveniently employed to evaluate the accuracy of the method. The recommended procedure is simple and accurate and has been adopted by Tecpar's laboratory of Parana Institute of Technology (Curitiba, Brazil).

Ocotea daphnifolia: phytochemical investigation, in vitro dual cholinesterase inhibition, and molecular docking studies

This study aimed to evaluate the anticholinesterase activities of extracts and fractions of Ocotea daphnifolia in vitro and characterize its constituents. The effects of hexane, ethyl acetate, and ethanolic extracts on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity were determined with a spectrophotometry assay. All extracts inhibited cholinesterase activity, and the ethanolic extract (2 mg/mL) exhibited the highest inhibition of both enzymes (99.7% for BuChE and 82.4% for AChE). The ethanolic extract was fractionated by column chromatography resulting in 14 fractions that were also screened for their anticholinesterase effects. Fraction 9 (2 mg/mL) showed the highest activity, inhibiting AChE and BuChE by 71.8% and 90.2%, respectively. This fraction was analyzed by high-performance liquid chromatography high-resolution mass spectrometry which allowed the characterization of seven glycosylated flavonoids (containing kaempferol and quercetin nucleus) and one alkaloid (reticuline). In order to better understand the enzyme-inhibitor interaction of the reticuline toward cholinesterase, molecular modeling studies were performed. Reticuline targeted the catalytic activity site of the enzymes. Ocotea daphnifolia exhibits a dual cholinesterase inhibitory activity and displays the same pattern of intermolecular interactions as described in the literature. The alkaloid reticuline can be considered as an important bioactive constituent of this plant.

The influence of storage method on the transparency of pig crystalline lens / A influência do método de armazenamento na transparência do cristalino de porco

ABSTRACT Purpose: The porcine eye is frequently used as a research model. This paper analyzes the effect of different storage methods on the transparency of pig crystalline lens. Methods: A spectral transmission curve (from 220 to 780 nm) for the crystalline lens was determined experimentally after storage in different conditions: saline solution, formalin, castor oil, and freezing at -80°C. The total transmission in the visible spectrum, which was used as an index of transparency, was calculated from these curves. For comparative purposes, fresh lenses were evaluated and used as controls. Results: Storing the porcine crystalline lens in saline solution or castor oil resulted in a transparency loss of approximately 10% after 24 h and storage in formalin resulted in a loss of nearly 30%. Storage by freezing at -80°C for 4 weeks maintained the transparency of the crystalline lens; the spectral transmission measured immediately after defrosting at room temperature coincided exactly with that of the freshly extracted lens. Conclusions: The transparency of porcine crystalline lens is affected by the storage method. The visible spectrum is the most affected, evidenced by the effect on the transparency and consequently the amount of light transmitted. The results show that freezing at -80°C maintains the transpa rency of the crystalline lens for at least 4 weeks.

RESUMO Objetivos: Olho de porco é frequentemente usa do como modelos de pesquisa. Este estudo analisa o efeito de di ferentes métodos de armazenamento na preservação da transparência do cristalino de porco. Métodos: Uma curva de transmissão espectral (de 220 até 780 nm) para o cristalino foi experimentalmente determinada após armazenamento em diferentes condições: solução salina, formol, óleo de mamona e congelamento a -80°C. Transmissão total do espectro visível, que foi usada como um índice de transparência foi calculada a partir dessas curvas. Para fins comparativos, lentes frescas foram avaliadas e usadas como controles. Resultados: O armazenamento do cristalino suíno em solução salina ou óleo de mamona resultou uma perda de transparência de aproximadamente 10% após 24 h e o armazenamento em formol resultou uma perda de quase 30%. O armazenamento por congelamento a -80°C durante 4 semanas manteve a transparência do cristalino; a transmissão espectral medida imediatamente após o descongelamen to à temperatura ambiente coincidiu exatamente com a da lente extraída recentemente. Conclusão: A transparência do cristalino suíno é afetada pelo método de armazenamento. O espectro visível é o mais afetado, evidenciado pelo efeito sobre a transparência e consequentemente a quantidade de luz transmitida. Os resultados mostram que o congelamento a -80°C mantém a transparência do cristalino suíno por pelo menos 4 semanas.

Prospecção de sideróforos do tipo hidroxamato e quinona para terapia de sobrecarga de ferro / Prospection of hydroxamate and quinone-type siderophores for iron overload chelation therapy

A sobrecarga de ferro é uma condição prejudicial para os pacientes, que apresentam uma diminuição significativa na qualidade de vida. Os fármacos quelantes são moléculas que têm capacidade de uso clínico para atuar como atenuadores da sobrecarga de metais. Neste trabalho apresentamos uma análise de sideróforos do tipo hidroxamato e quinona, com o objetivo de ampliar a gama de terapia de sobrecarga de ferro. Para cada composto foi realizado um ensaio competitivo com a sonda calce- ína para verificar a capacidade de ligação do ferro, e um ensaio antioxidante baseado na supressão da oxidação dependente de ferro da dihidrorrodamina (DHR) sob ascorbato. Foi observado que o hidroxamato cíclico piridoxatina apresentou capacidade de sequestrar ferro de substratos de alta afinidade, tanto em meio tamponado quanto em meio intracelular. Em ambas as situações também se mostrou um antioxidante eficiente. Entretanto, parece ser o mais tóxico do grupo dos hidroxamatos (que ainda continha o hidroxamato linear desferricoprogênio e o aromático desferriastercromo). Outros compostos naturais também foram estudados como possíveis candidatos a fármacos para sobrecarga de ferro. Complexos de ferro foram caracterizados por espectrofotometria para avaliar a estequiometria possível, considerando os sítios de ligação para cada composto. Ensaios de fluorescência revelaram que entre os quatro compostos em estudo (ácido clorogênico, lapachol, hemateína e hematoxilina), o complexo entre ferro e hemateína apresenta maior estabilidade relativa do que outros

Iron overload is a harmful condition for patients, who have a significant decrease in life quality. Chelating drugs are molecules that have the capacity for clinical use to act as attenuators of metal overload. In this work we present an analysis of hydroxamate and quinone-type siderophores, intending to broaden the range of iron overload therapy. For each compound it was conducted a competitive assay with the fluorescent probe calcein to verify the iron binding ability, and an antioxidant assay based on suppression of the iron-dependent oxidation of dihydrorhodamine (DHR) under ascorbate. It was observed that cyclic hydroxamate pyridoxatin displayed good ability to scavenge iron from high affinity substrates both in buffer and in intracellular medium. It was also an efficient antioxidant in both setups. However, pyridoxatin seems to be the most toxic from the hydroxamate group (composed also by the linear desferricoprogen and the aromatic desferriasterchrome). Other natural compounds have also been studied as possible candidates for iron-overload drug therapy. Iron complexes were characterized by spectrophotometry to assess the possible stoichiometry considering the binding sites for each compound. Fluorescence assays revealed that among the four compounds in study (chlorogenic acid, lapachol, hematein and hematoxylin), the complex between iron and hematein has higher relative stability than others

Salivary calcium and phosphate stability in different time and temperature storage

ABSTRACT The non-invasive collection and inexpensive nature of saliva has made it an attractive sample for use for diagnosis and research on several diseases. Storage circumstances may affect salivary component concentrations. The objective was to analyze calcium and phosphate stability in saliva samples stored at different conditions. Saliva of healthy people was stored and analyzed by spectrophotometry under different time and temperature conditions in order to evaluate calcium and phosphate stability. Calcium concentration was measured by Arsenazo III reaction at 600nm and phosphate by an acid-molybdate method at 650nm. Using Lin's concordance correlation coefficient (k), we observed very good agreement (k>0.8) for all samples frozen at -20 oC up to 50 days. Thaw/refreezing cycles can compromise phosphate stability even though there is good agreement (0.61<k<0.8). Because of higher variability for refrigerated samples, they are not the best storage method, although calcium and phosphate levels could be considered stable when the samples were stored at 4 oC for 7 days. Our results revealed that under different conditions, calcium and phosphate levels are stable in saliva samples, and that freezing at -20oC is the storage condition of choice, allowing to accumulate a higher number of samples before analysis, making it suitable for routine and research assays.

Color stability of ceramic brackets immersed in potentially staining solutions

OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

OBJETIVO: avaliar a estabilidade da cor de cinco tipos de braquetes cerâmicos após imersão em soluções potencialmente corantes.MÉTODOS: noventa braquetes foram divididos em 5 grupos (n = 18) de acordo com a marca comercial dos braquetes e as soluções em que foram imersos (café, vinho tinto, Coca-Cola e saliva artificial). Os baquetes avaliados foram Transcend (3M / Unitek, Monrovia, CA, EUA), Radiance (American Ortodontia, Sheboygan, WI, EUA), Mystique (GAC International Inc., Bohemia, NY, EUA) e Luxi II (Rocky Mountain Orthodontics, Denver, CO, EUA). Alterações cromáticas foram analisadas com o uso de um espectrofotômetro de reflectância e por inspecção visual, em cinco intervalos de tempo específicos. Os momentos de avaliação foram: 24 horas (T1), 72 horas (T2), 7 dias (T3) e 14 dias (T4) de imersão nas soluções. Os resultados foram submetidos à avaliação estatística com análise de variância e correção de Bonferroni, bem como a uma análise do perfil multivariada para amostras independentes e pareadas, com nível de significância de 5%.RESULTADOS: a duração do período de imersão influenciou na alteração de cor de todos os braquetes testados, mesmo admitindo-se que essas alterações nem sempre puderam ser observadas visualmente. Diferentes comportamentos foram observados em cada solução de imersão; no entanto, braquetes imersos em um mesmo tipo de solução progrediram de forma semelhante, apesar das pequenas variações.CONCLUSÕES: a coloração se tornou mais intensa com o tempo, e todos os braquetes sofreram alteração de cor nas soluções imersas.

Evaluación de la capacidad acumuladora de mercurio del ají (Capsicum annuum) / Evaluation of the mercury accumulating capacity of pepper (Capsicum annuum)

Objetivo Evaluar la capacidad acumuladora de mercurio por parte la planta de ají (Capsicum annuum), en suelos contaminados procedentes del corregimiento Mina Santa Cruz, Sur de Bolívar, Colombia, con el propósito de establecer el riesgo para la salud de la población consumidora. Materiales y Métodos Se tomaron muestras de tejidos (raíces, tallos y hojas) de plantas de C. annuum sembradas en dos suelos contaminados con mercurio y un suelo control, durante sus primeros cinco meses de crecimiento para determinar mercurio total mediante la técnica de espectrofotometría de absorción atómica por vapor frio. Se determinó mercurio total en muestras de frutos de ají consumido en Mina Santa Cruz. Resultados Las concentraciones medias de mercurio total en raíces fueron mayores en comparación con tallos y hojas. Los niveles de mercurio en suelos y el tiempo influyeron en la acumulación en tejidos. Las concentraciones de mercurio en frutos de C. annuum fueron bajas en relación a la ingesta tolerable semanal dispuesta por la OMS. Conclusión Los porcentajes de translocación de mercurio a las partes aéreas de la planta fueron bajos tanto en el suelo control como en los suelos contaminados. A pesar de los bajos niveles de mercurio en este alimento se debe disminuir al máximo el consumo de alimentos contaminados con dicho metal.(AU)

Objective To assess the mercury accumulating capacity in contaminated soils from the community of Mina Santa Cruz, in the south of the department of Bolívar, Colombia, of the pepper plant (Capsicum annuum), in order to establish the risk to the health of the consuming population. Materials and Methods Samples were taken from tissues (roots, stems, and leaves) of pepper plants grown in two soils contaminated with mercury and a control soil during the first five months of growth to determine total mercury through cold vapor atomic absorption spectrometry. Total mercury was determined in the samples of pepper plant fruits consumed in Mina Santa Cruz. Results The mean concentrations of total mercury in the roots were higher than in stems and leaves. Accumulation in tissues was influenced by mercury levels in soil and the growth time of the plants. Mercury concentrations in fruits of pepper plant were lower than tolerable weekly intake provided by WHO. Conclusion Percent of translocation of mercury to aerial parts of the plant were low in both control and contaminated soils. Despite low levels of mercury in this food, it is necessary to minimize the consumption of food contaminated with this metal.(AU)

Validation of a spectrophotometric method to determine ciprofibrate content in tablets / A validação de um método espectrofotométrico para determinar o conteúdo de ciprofibrato em comprimidos

Ciprofibrate is a drug indicated in cases of hypertriglyceridemia and mixed hyperlipidemia, but no monographs are available in official compendia for the analysis of this substance in tablets. The objective of this work was to develop and validate a spectrophotometric method for routine analysis of ciprofibrate in tablets. In this study, commercial and standard ciprofibrate were used, as well as placebo in absolute ethanol, analyzed by UV spectrophotometer. All tests followed the rules of Resolution RE-899, 2003. The results showed that the developed and validated method offers low cost, easy implementation, precision and accuracy, and may be included in the routine of quality control laboratories.

O ciprofibrato é um fármaco indicado em casos de hipertrigliceridemia e hiperlipidemia mista, mas não há monografias em compêndios oficiais para a análise desta substância em comprimidos. O objetivo deste trabalho é desenvolver e validar um método espectrofotométrico para análise de rotina de ciprofibrato em comprimidos. Neste estudo foram empregados ciprofibrato comercial, padrão e placebo em etanol absoluto, analisadas por espectrofotometria UV. Todos os testes seguiram as regras da Resolução RE- 899, 2003. Os resultados mostraram que o método desenvolvido e validado apresenta baixo custo, fácil implementação, precisão e exatidão e pode ser incluído em rotina de laboratórios de controle de qualidade.

Effect of surface sealant on the color stability of composite resin restorations

This study investigated the effect of sealant application on the color stability of composite resin restorations. Cavities in bovine incisors were restored with composite resin (Opallis; FGM) and the teeth were assigned to 4 groups (n=10). A sealant (Fill Glaze; Vigodent) was applied over the restorations of 2 groups. Baseline color measurements based on the CIEL*a*b* system were carried out using a spectrophotometer. Half the number of specimens was immersed in distilled water, and half was immersed in coffee 4 h/day. Color measurements were repeated after 1 h, 24 h, 7 days and 3 months. Data for each immersion solution were separately subjected to a two-way repeated measures ANOVA and Tukey’s test (α=0.05). For the group without sealant immersed in water, no significant differences were observed among the periods (p≥0.138), but the color was different compared with baseline (p<0.001). For the group with sealant application, the periods baseline, 1 h and 3 months presented similar results (p≥0.924). For groups immersed in coffee, when the sealant was not used, no significant differences were detected between the baseline and the periods 1 h and 24 h (p≥0.499), but the color changed significantly thereafter (p≤0.003). In the group with sealant, significant differences were detected for all periods compared with each other (p<0.001). In conclusion, application of sealant dramatically increased the staining of the restorations exposed to coffee.

Este estudo avaliou o efeito da aplicação de selante na estabilidade de cor de restaurações de compósito. Cavidades foram restauradas em incisivos bovinos com resina composta (Opallis, FGM) e os dentes separados em quatro grupos (n=10). O selante (Fill Glaze; Vigodent) foi aplicado sobre as restaurações em dois grupos. Aferição inicial de cor baseada no sistema CIEL*a*b* foi realizada com espectrofotômetro. Metade do número de espécimes foi imersa em água destilada, e metade imersa 4 h/dia em café. Aferições de cor foram repetidas após 1 h, 24 h, 7 dias e 3 meses. Os dados para cada solução de imersão foram submetidos separadamente à Análise de Variância de 2 vias para medidas repetidas e teste de Tukey (α=0,05). Para o grupo sem selante imerso em água, não foram observadas diferenças entre os períodos (p≥0,138), mas a cor foi diferente comparada à inicial (p<0,001). Para o grupo com selante, os períodos inicial, 1 h e 3 meses apresentaram resultados similares (p≥0,924). Para os grupos imersos em café, quando o selante não foi utilizado, não foram detectadas diferenças entre os períodos inicial, 1 h e 24 h (p≥0,499), mas a cor alterou significativamente após (p≤0,003). No grupo com selante, diferenças significativas foram detectadas para todos os períodos comparados entre si (p<0,001). Em conclusão, a aplicação de selante aumentou drasticamente o manchamento das restaurações expostas ao café.

Transcutaneous bilirubinometry in preterm neonates.

This prospective study was conducted to evaluate the accuracy of transcutaneous bilirubinometry in preterm newborns less than 32 weeks of gestation. Serum bilirubin values measured by direct spectrophotometry were considered as standard, the range was 2.2-12.5 mg/dL. 32 jaundiced infants of less than 32 weeks of gestation without phototherapy, including 10 ELBW neonates, were enrolled. Close correlation (R=0.933) existed between total serum bilirubin and transcutaneous bilirubin values measured over sternum.

Total polyphenols from syzygium cumini (L) skeels fruit extract / Polifenóis totais de Ssyzygium cumini (L) skeels extrato de frutas

A precise, accurate and low cost spectrophotometric method was developed and validated for routine determination of total polyphenols, as pyrogallic acid equivalents, from the percolated and lyophilized extract of Syzygium cumini (L.) Skeels fruits. Validation was assessed experimentally and data were rigorously treated by statistical analysis. Analytical parameters were: linearity, interval (range), precision and recovery/accuracy, limit of detection (LOD, μg mL-1) and limit of quantification (LOQ, μg mL-1). The visible spectrophotometric method presented linearity (r² = 0.9979 ± 0.0010) over the concentration range 0.25-7.5 μg mL-1 of standard pyrogallic acid, precision < 2.918171 percent, recovery/accuracy ranging from 96.228693 to 107.17701 percent, LOD = 0.21 μg mL-1 and LOQ = 0.64 μg mL-1.

Um método espectrofotométrico preciso, rigoroso e de baixo custo foi desenvolvido e validado para a determinação de polifenóis totais, utilizando-se como padrão o ácido pirogálico. O extrato dos frutos de Syzygium cumini (L.) Skeels foi preparado empregando-se o método de percolação com posterior liofilização. A validação foi executada experimentalmente e os dados foram submetidos à análise estatística. Os parâmetros analíticos considerados foram: linearidade, intervalos de precisão e de recuperação, limite de detecção (LD, μg.mL-1) e o limite de quantificação (LQ, μg.mL-1). O método espectrofotométrico apresentou linearidade (r² = 0,9979 + 0,0010) ao longo do intervalo de concentração de 0,25-7,5 μg mL-1 de ácido pirogálico, padrão de precisão menor do que 2,918171 por cento; recuperação/precisão entre 96,228693 a 107,17701 por cento, e LD = 0,21 μg-mL-1 e LOQ = 0,64 μg mL-1.

Comparison of two transcutaneous bilirubinometers--Minolta AirShields Jaundice Meter JM103 and Spectrx Bilicheck--in Thai neonates.

Transcutaneous bilirubin (TcB) has been reported to have a high correlation with serum bilirubin. The objectives of this study were: (1) to compare the accuracy of two transcutaneous bilirubinometer (Minolto AirShields Jaundice Meter, JM103 (JM) and SpectRx, Bilicheck (BC) in estimating total serum bilirubin (TSB) levels; and (2) to assess the predictive ability of transcutaneous bilirubin in relation to specific selected TSB levels. A total of 154 measurements of TcB, using JM and BC, and TSB were recruited from 134 term and near-term infants. Postnatal ages ranged from 19 to 160 hours (x = 64.7, SD = 25.6). TSB levels ranged from 4.5 to 17.5 mg/dl (x = 10.4, SD = 2.5). The correlation coefficients between TcB (JM and BC) and TSB measurements were significant and similar (r 0.80 and 0.82, respectively). The errors of distribution were, for TSB and TcB-JM, the mean difference of 0.7 mg/dl (SD 1.6 mg/dl and 95% confidence interval of the mean (CI) 0.4 and 1.0]; and, for TSB and TcB-BC, the mean difference of -0.6 mg/dl (SD 1.5 mg/dl and 95% CI -0.4 and -0.8). TcB-JM had a tendency to underestimate TSB levels, and TcB-BC had a tendency to overestimate TSB levels. The sensitivity of BC was higher, but specificity was lower, than JM in corresponding to different TSB levels, except at a TSB level of 15 mg/dl when both instruments yielded 100% sensitivity. The accuracy of JM in predicting TSB was higher than BC at all TSB levels. Operating the JM was simple and uncomplicated. It would be suitable for clinical use when a number of personnel perform the measurement.

Effectiveness of composite resin polymerization using light-emitting diodes (LEDs) or halogen-based light-curing units

A longevidade clínica das resinas compostas é grandemente influenciada pela qualidade do aparelho fotopolimerizador utilizado. O objetivo deste trabalho foi comparar a eficácia de um aparelho fotopolimerizador de diodos emissores de luz e a de um de luz halógena através do grau de penetração de um corante em uma resina composta micro-híbrida. A resina composta utilizada (Filtek Z250/3M Dental) foi inserida em matrizes acrílicas e fotopolimerizada por 40 segundos por um aparelho fotopolimerizador de diodos emissores de luz (Ultraled/Dabi Atlante) ou de luz halógena (Degulux/Degussa Hüls). Imediatamente depois, os corpos-de-prova foram imersos em 1 ml de solução de azul de metileno a 2% e mantidos em estufa a 37ºC ± 2ºC. Após 24 horas, foram lavados com água corrente destilada por 1 minuto e armazenados em estufa a 37ºC ± 2ºC em umidade relativa por 24 horas. As resinas compostas foram removidas das matrizes, individualmente trituradas e imersas em 1 ml de álcool absoluto por 24 horas. As soluções foram filtradas e centrifugadas por 3 minutos a 4.000 rpm, e o sobrenadante foi utilizado para determinar a absorbância em um espectrofotômetro a 590 nm. O teste t foi aplicado para verificar as diferenças entre os grupos. Não houve diferenças estatísticas entre os grupos fotopolimerizados por diodos emissores de luz ou luz halógena (p > 0,05). O aparelho fotopolimerizador de diodos emissores de luz apresentou a mesma efetividade em polimerizar uma resina composta micro-híbrida quanto o de luz halógena.

Biokinetics of inorganic iron in female volunteers

Iron biokinetics of absorption and disposition were investigated following a single oral dose of 150 mg ferrous sulfate to 10 healthy female volunteers. The blood and serum samples collected at different time intervals were analyzed by atomic absorption spectrophotometer. Total iron in blood showed about 25% lower values than those given in literature. In blood, iron showed mean +/- SD value of Tmax 2.37 +/- 0.17 hours, Cmax 422 +/- 26.9 mcg.m/L t1/2mcg 0.54 +/- 0.03 hour, kabs 1.29 +/- 0.08/h, AUC 6923 +/- 1624 h.mg/L, CI 0.36 +/- 0.00 mL/h/Kg, Vd 5.36 +/- 0.02 mL/Kg and t1/2B 9.54 +/- 2.07 hour. In serum, iron showed mean ' SD values of Tmax 6.73 +/- 0.00 hour, Cmax 10.8 +/- 0.57 mcg.m/L, t1/2mcg 8.05 +/- 1.32 hour, kabs 0.09 +/- 0.01/h, AUC 412 +/- 91.8 h.mg/L, CI 6.80 +/- 0.07 mL/h/Kg, Vd 82.5 +/- 0.55 mL/Kg and t1/2B 8.59 +/- 0.96 hour

Valores de referência do ácido delta-aminolevulínico na urina de populaçäo da regiäo sul de Minas Gerais, näo ocupacionalmente exposta ao chumbo / Reference values for urinary delta-aminolevulinic acid (ALA) in a lead nonoccupationally exposed population from South Minas Gerais, Brazil

Neste trabalho determinaram-se os valores de referência para o ácido delta-aminolevulínico urinário (`deltaï-ALA U), indicador biológico da exposição humana aos compostos inorgânicos do chumbo, na região Sul de Minas Gerais. O `deltaï-ALA U foi determinado segundo método espectrofotométrico de Tomokuni e Ogata. A população estudada foi constituída de 117 voluntários não-expostos ocupacionalmente ao chumbo, saudáveis, sendo 56 homens e 64 mulheres, de idades entre 18 e 60 anos, Os valores de referência do `deltaï-ALA U, expressos em mg/g de creatinina, foram: valor médio ñ desvio padrão de 1,51 ñ 0,53; mediana de 1,40; intervalo de confiança 95 por cento entre 1,41 e 1,61; valor de referência superior de 2,59; percentil 95 por cento de 2,45...

Serum zinc level in children with malnutrition

Serum zinc level amongst children with protein energy malnutrition [PEM] was evaluated in a control study conducted in the Department of Paediatrics, Allama lqbal Medical College and Jinnah Hospital, Lahore. Twenty-five children with PEM and 25 healthy children as control from the community were screened. Mean serum zinc level was found to be 54.48 +/- 18.91 mg/dl in children with PEM while it was 72.72 +/- 8.21 mg/dl in control group [P< 0.001]. No significant difference in zinc level was noted between both sexes in each group. Marasmic 16 children revealed mean serum zinc level of 57.55 +/- 18.16 mg/dl while in Kwashiorkor it was 44.57 +/- 13.66 mg/dl. Serum zinc was significantly low in Kwashiorkor than in marasmus [P < 0.001]. It was also significantly low in children with acute or chronic diarrhoea associated with malnutrition [44.66 +/- 16.0 mg/dl]. Acute respiratory infections in these children were not associated with low serum zinc level [71.66 +/- 16.51 mg/dl]

Validación de espectrofotómetro portátil para el estudio del reflujo duodeno-gastro-esofágico / Validation of portable spectrophotometer in the study of duodenogastroesophageal reflux

Además del reflujo ácido, el reflujo de componentes duodenales en el esófago ha sido postulado como factor asociado a la génesis de la esofagitis por reflujo y especialmente al esófago de Barrett, aunque su pesquisa era difícil o muy inexacta. Un espectrofotómetro portátil para la detección de bilirrubina como marcador de reflujo duodenal en el esófago fue evaluado a través de pruebas in vitro, para estudiar su capacidad de detectar este pigmento en condiciones que simulaban el medio gastroesofágico. El sistema demostró gran linearidad de respuesta en concentraciones de bilirrubina menores de 5 mg/dl y no se observó falsos positivos en otros componentes del contenido gástrico. La pesquisa de bilirrubina es levemente subestimada en un medio ácido y episodios de reflujo más breves que 20 s pueden ser no detectados. En estudios clínicos, el sistema permitió observar gran reflujo biliar (31,6 por ciento del tiempo) en el esófago de pacientes con esófago de Barrett, siendo estos valores significativamente mayores que en pacientes con reflujo gastroesofágico (RGE) sin Barrett (5,2 por ciento) y en controles (2,1 por ciento). La bilimetría ambulatoria portátil puede aportar valiosa información en el estudio del RGE