Determination of a new constant to estimate glomerular filtration rate in pediatrics. / Determinación de una nueva constante para la estimación del filtrado glomerular en pediatría.

INTRODUCTION: In pediatrics, glomerular filtration rate (GFR) may be estimated by measured corrected creatinine clearance (mcCrCl) (mL/min/1.73 m2) or the Schwartz formula (eGFR = height/plasma creatinine x k). The constant k depends on the plasma creatinine determination method: k = 0.55 for the Jaffe colorimetric method and k = 0.413 for the enzymatic method. Our laboratory uses the compensated kinetic colorimetric assay (CKC), and differences are observed between the estimated and measured GFR. Hypothesis: The proposed values of k do not adjust to the CKC method for plasma creatinine. OBJECTIVE: To calculate a k value that allows to estimate GFR through creatinine measurement with CKC. METHODS: Correlational, descriptive design. Patients aged 3-18 years seen at the Division of Pediatric Nephrology between July 2017 and January 2018 with normal or altered GFR, bladder and bowel control, and signed consent were included. Malnourished and myelomeningocele patients were excluded. Studied variables were plasma and urine creatinine, height, and 24-hour urine output. RESULTS: A total of 184 patients were analyzed, their mean age was 10 years. Median mcCrCl was 123 mL/min/1.73 m2. The linear correlation between height and plasma creatinine and mcCrCl resulted in a k value of 0.499 (r = 0.974 and r2 = 0.949). The linear correlation between the estimated GFR (k = 0.499) and mcCrCl resulted in a 0.999 ß coefficient (r = 0.951 and r2 = 0.903). CONCLUSION: According to this study, the constant that allows to estimate GFR when measuring plasma creatinine with the CKC method is 0.499.

Introducción. En pediatría, el filtrado glomerular (FG) se puede calcular con el clearance (depuración) de creatinina medida corregida en ml/min/1,73 m2, o se puede estimar según la fórmula de Schwartz (FGe = talla/ creatinina plasmática x k). La constante k depende del método de determinación de creatinina plasmática: k = 0,55 para el método colorimétrico de Jaffe, y k =0,413 para el método enzimático. Nuestro laboratorio utiliza el método colorimétrico cinético compensado (MCCC), se observan discordancias entre el FG estimado y el medido. Hipótesis: Los valores de k propuestos no se ajustan al MCCC de creatinina plasmática. Objetivo. Calcular el valor de k que permita estimar el FG mediante la cuantificación de la creatinina con el MCCC. Métodos. Diseño descriptivo correlacional. Se incluyeron pacientes de entre 3 y 18 años con FG normal o alterado atendidos en el Servicio de Nefrología Infantil entre julio de 2017 y enero de 2018 con control de esfínteres y firma del consentimiento. Se excluyeron pacientes desnutridos y con mielomeningocele. Las variables estudiadas fueron: creatinina plasmática y urinaria, talla y diuresis de 24 horas. Resultados. Se analizaron 184 pacientes, con una edad media de 10 años. La mediana del clearance de creatinina medido corregido fue de 123 ml/ min/1,73 m2. La correlación lineal entre la talla y la creatinina plasmática y el clearance de creatinina medido corregido arrojó un valor de k de 0,499 (r = 0,974 y r2 = 0,949). La correlación lineal entre el FG estimado (k = 0,499) y el clearance de creatinina medido corregido mostró un coeficiente b = 0,999 (r = 0,951 y r2= 0,903). Conclusión. Según este estudio, la constante que permite estimar el filtrado glomerular al cuantificar la creatinina plasmática con el método colorimétrico cinético compensado es de 0,499.

Determinación de una nueva constante para la estimación del filtrado glomerular en pediatría / Determination of a new constant to estimate glomerular filtration rate in pediatrics

Introducción. En pediatría, el filtrado glomerular (FG) se puede calcular con el clearance (depuración) de creatinina medida corregida en ml/min/1,73 m2, o se puede estimar según la fórmula de Schwartz (FGe = talla/creatinina plasmática x k). La constante k depende del método de determinación de creatinina plasmática: k = 0,55 para el método colorimétrico de Jaffe, y k =0,413 para el método enzimático. Nuestro laboratorio utiliza el método colorimétrico cinético compensado (MCCC), se observan discordancias entre el FG estimado y el medido.Hipótesis: Los valores de k propuestos no se ajustan al MCCC de creatinina plasmática. Objetivo. Calcular el valor de k que permita estimar el FG mediante la cuantificación de la creatinina con el MCCC. Métodos. Diseño descriptivo correlacional. Se incluyeron pacientes de entre 3 y 18 años con FG normal o alterado atendidos en el Servicio de Nefrología Infantil entre julio de 2017 y enero de 2018 con control de esfínteres y firma del consentimiento. Se excluyeron pacientes desnutridos y con mielomeningocele. Las variables estudiadas fueron: creatinina plasmática y urinaria, talla y diuresis de 24 horas. Resultados. Se analizaron 184 pacientes, con una edad media de 10 años. La mediana del clearance de creatinina medido corregido fue de 123 ml/min/1,73 m2. La correlación lineal entre la talla y la creatinina plasmática y el clearance de creatinina medido corregido arrojó un valor de k de 0,499 (r = 0,974 y r2 = 0,949). La correlación lineal entre el FG estimado (k = 0,499) y el clearance de creatinina medido corregido mostró un coeficiente b = 0,999 (r = 0,951 y r2= 0,903). Conclusión. Según este estudio, la constante que permite estimar el filtrado glomerular al cuantificar la creatinina plasmática con el método colorimétrico cinético compensado es de 0,499.

Introduction. In pediatrics, glomerular filtration rate (GFR) may be estimated by measured corrected creatinine clearance (mcCrCl) (mL/min/1.73 m2) or the Schwartz formula (eGFR = height/plasma creatinine x k). The constant k depends on the plasma creatinine determination method: k = 0.55 for the Jaffe colorimetric method and k = 0.413 for the enzymatic method. Our laboratory uses the compensated kinetic colorimetric assay (CKC), and differences are observed between the estimated and measured GFR.Hypothesis: The proposed values of k do not adjust to the CKC method for plasma creatinine. Objective. To calculate a k value that allows to estimate GFR through creatinine measurement with CKC. Methods. Correlational, descriptive design. Patients aged 3-18 years seen at the Division of Pediatric Nephrology between July 2017 and January 2018 with normal or altered GFR, bladder and bowel control, and signed consent were included. Malnourished and myelomeningocele patients were excluded. Studied variables were plasma and urine creatinine, height, and 24-hour urine output. Results. A total of 184 patients were analyzed, their mean age was 10 years. Median mcCrCl was 123 mL/min/1.73 m2. The linear correlation between height and plasma creatinine and mcCrCl resulted in a k value of 0.499 (r = 0.974 and r2 = 0.949). The linear correlation between the estimated GFR (k = 0.499) and mcCrCl resulted in a 0.999 ß coefficient (r = 0.951 and r2 = 0.903). Conclusion. According to this study, the constant that allows to estimate GFR when measuring plasma creatinine with the CKC method is 0.499.

Monitoring cellulose oxidation for protein immobilization in paper-based low-cost biosensors.

The oxidation of paper by periodate was investigated and systematically characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, X-ray diffraction, goniometry, and dynamic mechanical analysis. For the first time, in situ FTIR microscopy analysis was performed, yielding chemical images of carbonyl groups on the cellulose fibers. The enhancement of protein immobilization on oxidized paper was quantified by a colorimetric assay with Ponceau dye, demonstrating that 0.5-h oxidation suffices to functionalize the paper-based devices. The oxidized paper was applied as a sensor for protein quantification in urine, a test able to detect levels of proteinuria and even microalbuminuria. The quantification was based on the capture of proteins through covalent bonds formed with the carbonyl groups on the oxidized paper followed by the staining of the region with Ponceau dye. There is a linear dependency between human serum albumin (HSA) concentration and the length of the stained blot from 0.1 to 3 mg mL-1. This method correlated linearly with a reference method showing a higher sensitivity (0.866 cm mL mg-1) than the latter. The limit of quantification was 0.1 mg mL-1, three times lower than that of the commercial strip. Graphical abstract Paper oxidation with periodate and extensive characterization, including microspectroscopy. The conversion of cellulose hydroxyl groups to aldehyde enhances covalent immobilization of protein on paper for application as analytical device. The oxidized paper determined protein in urine, suitable for proteinuria diagnosis.

Microwave Application for Controlling Oryzaephilus surinamensis Insects Infesting Dried Figs and Evaluation of Product Color Changes Using an Image Processing Technique.

In this study, microwave heating was employed for controlling Oryzaephilus surinamensis adult beetles infesting stored Iranian dried figs. The dried fig samples were artificially infested with O. surinamensis and then heated in a microwave oven (2,450 MHz) at power outputs of 450, 720, and 900 W for 20, 30, 40, and 50 s. Changes in the color of the samples after these microwave applications were evaluated for lightness (ΔL*), redness (Δa*), and yellowness (Δb*) using an image processing technique. Both parameters of microwave power and exposure time had significant effects on beetle mortality ( P < 0.01). A direct positive relationship was found between the mortality rate and microwave power. Complete mortality was achieved at 900 W and for 50 s. The color parameters of the dried fig samples did not change significantly. These results indicate that microwave irradiation can be introduced as an appropriate alternative to chemical fumigants without affecting product quality.

Biological characterization of implant surfaces - in vitro study / Caracterização biológica de superfície de titânio - estudo in vitro

Objective: Evaluate the biological performance of titanium alloys grade IV under different surface treatments: sandblasting and double etching (Experimental surface 1; Exp1, NEODENT); surface with wettability increase (Experimental surface 2; Exp2, NEODENT) on response of preliminary differentiation and cell maturation. Material and method: Immortalized osteoblast cells were plated on Exp1 and Exp2 titanium discs. The polystyrene plate surface without disc was used as control group (C). Cell viability was assessed by measuring mitochondrial activity (MTT) at 4 and 24 h (n = 5), cell attachment was performed using trypan blue exclusion within 4 hours (n = 5), serum total protein and alkaline phosphatase normalization was performed at 4, 7 and 14 days (n = 5). Data were analyzed using one-way ANOVA and Tukey test. Result: The values of cell viability were: 4h: C - 0.32±0.01A; Exp1 - 0.34±0.08A; Exp2 - 0.29±0.03A. 24h: C - 0.43±0.02A; Exp1 - ; 0.39±0.01A; Exp2 - 0.37±0.03A. The cell adhesion counting was: C -85±10A; Exp1- 35±5B; Exp2& - 20±2B. The amounts of serum total protein were 4d: C - 40±2B; Exp1 - 120±10A; Exp2 -130±20A. 7d: C 38±2B; Exp1 - 75±4A; Exp2 -70±6A. 14 d: C - 100±3A; Exp1 - 130±5A; Exp2 - 137±9A. The values of alkaline phosphatase normalization were: 4d: C - 2.0±0.1C; Exp1 - 5.1±0.8B; Exp2 - 9.8±2.0A<. 7d: C -1.0±0.01C; Exp1 - 5.3±0.5A; Exp2 - 3.0±0.3B. 14 d: C - 4.1±0.3A; Exp1 - 4.4±0.8A; Exp2 - 2.2±0.2B. ...

Objetivo: Avaliar o desempenho biológico de ligas de titânio grau IV submetidos a diferentes tratamentos de superfície - jateamento e duplo ataque ácido (Superfície experimental 1; Exp1, NEODENT) e superfície com aumento na molhabilidade (Superfície experimental 2; Exp2, NEODENT) em resposta preliminar de diferenciação e maturação celular. Material e método: Foram plaqueados osteoblastos imortalizados sobre discos de titânio de Exp1 e Exp2 e como controle o poço da placa de cultura sem disco (C). Empregou-se ensaios de viabilidade celular (MTT) em 4 e 24 horas (n = 5), adesão celular em 4 horas (n = 5), dosagem de proteínas totais e fosfatase alcalina normalizada em 4, 7 e 14 dias (n = 5). Os dados foram analisados por ANOVA em fator único seguido de teste de Tukey. Resultado: Os valores de viabilidade celular foram: 4h: C - 0,32±0,01A; Exp1 - 0,34±0,08A; Exp2 - 0,29±0,03A. 24h: C - 0,43±0,02A; Exp1 - 0,39±0,01A; Exp2 - 0,37±0,03A. A contagem de adesão celular foi: C - 85±10A; Exp1 - 35±5B; Exp2 - 20±2B. Os valores de proteínas totais foram: 4d: C - 40±2B; Exp1 - 120±10A; Exp2 - 130±20A. 7d: C - 38±2B; Exp1 - 75±4A; Exp2 - 70±6A. 14 d: C - 100±3A; Exp1 - 130±5A; Exp2 - 137±9A. Os valores de fosfatase alcalina normalizada foram: 4d: C - 2,0±0,1C; Exp1 - 5,1±0,8B; Exp2 - 9,8±2,0A, 7d: C - 1,0±0,01C; Exp1 - 5,3±0,5A; Exp2 - 3,0±0,3B, 14 d: C - 4,1±0,3A; Exp1 - 4,4±0,8A; Exp2 - 2,2±0,2B. Letras diferentes representam ...

Desarrollo y validación de un método de determinación por espectrofotometría visible de antimoniato de meglumina en inyectables / Development and validation of a colorimetric assay for the determination of meglumine antimoniate in injections

En este artículo se presentan los resultados del desarrollo y de la validación de un método analítico para realizar la determinación de antimoniato de meglumina en un inyectable para uso humano. El método se funda en la medida de la absorción a 352 nm de la coloración producida al hacer reaccionar el antimoniato de meglumina con yoduro de potasio en medio ácido. El método validado se desarrolló para hacer la determinación del antimoniato de meglumina como parte del control de calidad y para llevar a cabo estudios de estabilidad de la molécula en el inyectable. Como variables de validación se estudiaron la selectividad, la linealidad, la precisión, la exactitud y la robustez.

In this paper we present the results obtained during the development and validation of an analytical methodology by a colorimetric method for the assay of meglumine antimoniate in injections. The quantification implies the formation of a colored complex resulting after of meglumine antimoniate and potassium iodure in acid media. The absorbance was made at 352 nm. The validated methodology may be used as a part of quality control with release purpose and also, in chemical stability studies of the injections. As validation parameters, we studied selectivity, lineality, precision, accuracy and robustness.