Identification and quantification of glucose degradation products in heat-sterilized glucose solutions for parenteral use by thin-layer chromatography.

During heat sterilization of glucose solutions, a variety of glucose degradation products (GDPs) may be formed. GDPs can cause cytotoxic effects after parenteral administration of these solutions. The aim of the current study therefore was to develop a simple and quick high-performance thin-layer chromatography (HPTLC) method by which the major GDPs can be identified and (summarily) quantified in glucose solutions for parenteral administration. All GDPs were derivatized with o-phenylenediamine (OPD). The resulting GDP derivatives (quinoxalines) were applied to an HPTLC plate. After 20 minutes of chamber saturation with the solvent, the HPTLC plate was developed in a mixture of 1,4-dioxane-toluene-glacial acetic acid (49:49:2, v/v/v), treated with thymol-sulfuric acid spray reagent, and heated at 130°C for 10 minutes. Finally, the GDPs were quantified by using a TLC scanner. For validation, the identities of the quinoxaline derivatives were confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Glyoxal (GO)/methylglyoxal (MGO) and 3-deoxyglucosone (3-DG)/3-deoxygalactosone (3-DGal) could be identified and quantified in pairs, glucosone (2-KDG), 5-hydroxymethylfurfural (5-HMF), and 3,4-dideoxyglucosone-3-ene (3,4-DGE) each individually. For 2-KDG, the linearity of the method was demonstrated in the range of 1-50 µg/mL, for 5-HMF and 3,4-DGE 1-75 µg/mL, for GO/MGO 2-150 µg/mL, and for 3-DG/3-DGal 10-150 µg/mL. All GDPs achieved a limit of detection (LOD) of 2 µg/mL or less and a limit of quantification (LOQ) of 10 µg/mL or less. R2 was 0.982 for 3.4-DGE, 0.997 for 5-HMF, and 0.999 for 2-KDG, 3-DG/3-DGal, and GO/MGO. The intraday precision was between 0.4 and 14.2% and the accuracy, reported as % recovery, between 86.4 and 112.7%. The proposed HPTLC method appears to be an inexpensive, fast, and sufficiently sensitive approach for routine quantitative analysis of GDPs in heat-sterilized glucose solutions.

A standardized glucose-insulin-potassium infusion protocol in surgical patients: Use of real clinical data from a clinical data warehouse.

AIMS: We evaluated the clinical usefulness of a new unified glucose-insulin-potassium (GIK) regimen in a general surgical department. METHODS: Surgical patients treated under the previous diverse GIK regimens (September 2016 to August 2017) and the new unified GIK regimen (September 2017 to August 2018) were identified in records of the Clinical Data Warehouse of Seoul National University Bundang Hospital. Serial and area under the curve (AUC) glucose levels, and percentages of time within the target glucose levels were compared in propensity score matched patients in the diverse GIK regimen and in the unified GIK regimen (n = 227 in each group). RESULTS: The AUC of glucose at 6 h and 12 h was lower under the unified GIK regimen than the diverse GIK regimen. The percentage of target glucose levels was higher in the unified GIK regimen compared to the diverse GIK regimen (81.5% vs. 75.0%, P = 0.026), but the occurrence of hypoglycaemia did not differ significantly between groups. CONCLUSIONS: The unified GIK regimen was more effective than the diverse GIK regimen for glycaemic control and did not increase the number of patients developing hypoglycaemia. This validated written GIK regimen can be safely used in a general surgical department.

The EuBIVAS: Within- and Between-Subject Biological Variation Data for Electrolytes, Lipids, Urea, Uric Acid, Total Protein, Total Bilirubin, Direct Bilirubin, and Glucose.

BACKGROUND: The European Federation of Clinical Chemistry and Laboratory Medicine European Biological Variation Study (EuBIVAS) has been established to deliver rigorously determined data describing biological variation (BV) of clinically important measurands. Here, EuBIVAS-based BV estimates of serum electrolytes, lipids, urea, uric acid, total protein, total bilirubin, direct bilirubin, and glucose, as well as their associated analytical performance specifications (APSs), are presented. METHOD: Samples were drawn from 91 healthy individuals (38 male, 53 female; age range, 21-69 years) for 10 consecutive weeks at 6 European laboratories. Samples were stored at -80 °C before duplicate analysis of all samples on an ADVIA 2400 (Siemens Healthineers). Outlier and homogeneity analyses were performed, followed by CV-ANOVA on trend-corrected data, when relevant, to determine BV estimates with CIs. RESULTS: The within-subject BV (CVI) estimates of all measurands, except for urea and LDL cholesterol, were lower than estimates available in an online BV database, with differences being most pronounced for HDL cholesterol, glucose, and direct bilirubin. Significant differences in CVI for men and women/women <50 years of age were evident for uric acid, triglycerides, and urea. The CVA obtained for sodium and magnesium exceeded the EuBIVAS-based APS for imprecision. CONCLUSIONS: The EuBIVAS, which is fully compliant with the recently published Biological Variation Data Critical Appraisal Checklist, has produced well-characterized, high-quality BV estimates utilizing a stringent experimental protocol. These new reference data deliver revised and more exacting APS and reference change values for commonly used clinically important measurands, thus having direct relevance to diagnostics manufacturers, service providers, clinical users, and ultimately patients.

Systematic review of preservation solutions for allografts for liver transplantation based on a network meta-analysis.

AIMS: The aim of this work was to determine the best preservation solutions for allografts for liver transplantation by quantitative network meta-analysis. METHODS: Global electronic databases including PubMed, EMBASE, and Cochrane Library were searched for relevant randomized controlled trials. Seven pieces of parametric data were extracted from included studies for pooled estimation. A consistency model was used for direct and indirect comparisons. The cumulative probability P value was utilized to rank the solutions. A node-splitting model was utilized for testing the consistency of final data. Quality of evidence was assessed using the GRADE (Grades of Recommendations Assessment, Development and Evaluation) system. RESULTS: Eleven 2-arm trials including 1319 patients and 5 different solutions were finally included. HTK (Histidine-tryptophan-ketoglutarate) solution exhibited the best efficacy for decreasing the primary dysfunction rate, biliary complications and ICU-stay time (probability P = 0.43, 0.45 and 0.58, respectively). Celsior solution significantly decreased the rate of rejection and early retransplantation (probability P = 0.73 and 0.38, respectively), and enhanced patient and graft survival (probability P = 0.90 and 0.98, respectively) more than did other solutions. Overall, the quality of evidence was rated high or moderate. CONCLUSIONS: We suggested that HTK solution may offer the best safety during the perioperative period. However, Celsior solution led to better graft tolerance and exhibited greater benefit for long-term outcomes. And our conclusions still need to be further validated.

Calcium Chloride and Calcium Gluconate in Neonatal Parenteral Nutrition Solutions without Cysteine: Compatibility Studies Using Laser Light Obscuration Methodology.

There are no compatibility studies for neonatal parenteral nutrition solutions without cysteine containing calcium chloride or calcium gluconate using light obscuration as recommended by the United States Pharmacopeia (USP). The purpose of this study was to do compatibility testing for solutions containing calcium chloride and calcium gluconate without cysteine. Solutions of TrophAmine and Premasol (2.5% amino acids), containing calcium chloride or calcium gluconate were compounded without cysteine. Solutions were analyzed for particle counts using light obscuration. Maximum concentrations tested were 15 mmol/L of calcium and 12.5 mmol/L of phosphate. If the average particle count of three replicates exceeded USP guidelines, the solution was determined to be incompatible. This study found that 12.5 and 10 mmol/L of calcium and phosphate, respectively, are compatible in neonatal parenteral nutrition solutions compounded with 2.5% amino acids of either TrophAmine or Premasol. There did not appear to be significant differences in compatibility for solutions containing TrophAmine or Premasol when solutions were compounded with either CaCl2 or CaGlu-Pl. This study presents data in order to evaluate options for adding calcium and phosphate to neonatal parenteral nutrition solutions during shortages of calcium and cysteine.

Análisis de desempeño de laboratorios clínicos en la determinación de glucosa y creatinina / Performance analysis of clinical laboratory in glucose and creatinine determinations / Análise de desempenho de laboratórios clínicos na determinação de glicose e creatinina

Los Programas de Evaluación Externa de la Calidad (PEEC) de los laboratorios clínicos (LC) son indispensables para la comparación del desempeño en una o varias determinaciones de analitos entre diferentes laboratorios. Se evaluó el desempeño de los LC del estado Carabobo en la determinación de las concentraciones séricas de glucosa y creatinina. El estudio fue no experimental, descriptivo, de campo y de corte transversal. Se evaluaron 22 laboratorios entre públicos y privados del estado Carabobo. Se distribuyeron a cada LC 5 sueros controles (SC) nivel I (NI) y 5 nivel II (NII) para glucosa y creatinina. Se evaluó la imprecisión intra- e interlaboratorios, el sesgo y el error total de los resultados. No hubo LC con competencia para la determinación de glucosa y creatinina en ambos niveles ensayados. Solo 3 (13,3%) LC fueron competentes en la determinación de creatinina en el NI y NII. Se concluye que los resultados obtenidos en los SC de glucosa y creatinina no pueden ser transferibles entre los diferentes LC, por lo que es importante poner en marcha programas de control de calidad intralaboratorios o mejorar los existentes para eliminar los errores sistemáticos y disminuir los aleatorios, así como también se hace necesaria la participación en PEEC para determinar la universalización de los resultados emitidos por los LC.

External Quality Assessment Schemes (EQAS) of clinical laboratories (CL) are indispensable to compare performance in one or more analyte determinations among different laboratories. Performance of CL in Carabobo state for the determination of serum glucose and creatinine was evaluated. The study was not experimental, descriptive and cross-sectional field. A total of 22 public and private laboratories in Carabobo state were evaluated. Each CL was distributed 5 control sera (CS) level I (LI) and 5 level II (LII) for glucose and creatinine. Intra- and inter-laboratory precision, bias and total error of the results were evaluated. There was no CL competition for determining glucose and creatinine both levels tested. Only 3 (13.3%) CL were proficient in the determination of creatinine in the LI and LII. It can be concluded that the results obtained in CS glucose and creatinine may not be transferable between different CL, so it is important to implement quality control programs within laboratories or improve the existing ones to eliminate systematic errors and reduce randomization; besides, participation in EQAS is also necessary to determine the universalization of the CL results.

Os Programas de Avaliação Externa da Qualidade (PAEQ) dos laboratórios clínicos (LC) são essenciais para comparar o desempenho numa ou varias determinações de analitos entre diferentes laboratórios. Avaliou--se o desempenho dos LC do estado Carabobo na determinação das concentrações séricas de glicose e creatinina. O estudo foi não experimental, descritivo, de campo e seção transversal. Avaliaram-se 22 laboratórios entre públicos e privados do estado Carabobo. Foram distribuídos a cada laboratórios 5 soros controle (SC) nível I (NI) y 5 soros controle nível II (NII) para a glicose e creatinina. Foi avaliada a imprecisão intra e inter-laboratórios, o desvio percentual relativo e o erro total dos resultados. Não houve LC com competência para a determinação de glicose e creatinina em ambos os níveis testados. Apenas 3 (13,3%) LC foram competentes na determinação de creatinina no NI e NII. Conclui-se que os resultados obtidos nos SC de glicose e creatinina não podem ser transferíveis entre os diferentes LC, por isso é importante implementar programas de controle de qualidade intralaboratórios ou melhorar os já existentes para eliminar erros sistemáticos e reduzir os aleatórios; bem como se torna necessária a participação em PAEQ, para determinar a universalização dos resultados emitidos pelos LC.

Bacteria-Templated NiO Nanoparticles/Microstructure for an Enzymeless Glucose Sensor.

The bacterial-induced hollow cylinder NiO (HCNiO) nanomaterial was utilized for the enzymeless (without GOx) detection of glucose in basic conditions. The determination of glucose in 0.05 M NaOH solution with high sensitivity was performed using cyclic voltammetry (CV) and amperometry (i-t). The fundamental electrochemical parameters were analyzed and the obtained values of diffusion coefficient (D), heterogeneous rate constant (ks), electroactive surface coverage (Г), and transfer coefficient (alpha-α) are 1.75 × 10(-6) cm²/s, 57.65 M(-1)·s(-1), 1.45 × 10(-10) mol/cm², and 0.52 respectively. The peak current of the i-t method shows two dynamic linear ranges of calibration curves 0.2 to 3.5 µM and 0.5 to 250 µM for the glucose electro-oxidation. The Ni(2+)/Ni(3+) couple with the HCNiO electrode and the electrocatalytic properties were found to be sensitive to the glucose oxidation. The green chemistry of NiO preparation from bacteria and the high catalytic ability of the oxyhydroxide (NiOOH) is the good choice for the development of a glucose sensor. The best obtained sensitivity and limit of detection (LOD) for this sensor were 3978.9 µA mM(-1)·cm(-2) and 0.9 µM, respectively.

Influence of 5% dextrose volume on amphotericin B deoxycholate preparation.

OBJECTIVES: Preparation of amphotericin B deoxycholate (AmB-d) in different volumes of 5% dextrose (D5W) was studied to investigate a interesting phenomenon that AmB-d was easy to bring pipe blockage when diluted in 500 ml but not in 50 ml. METHODS: AmB-d (25 mg/vial) in 50 ml, 250 ml or 500 ml D5W was prepared. Fluids were collected before and after infusion, then were assayed by validated high-performance liquid chromatography (HPLC) method. Light obscuration assay was used to detect the particles in transfusions. KEY FINDINGS: pH values of different volumes of D5W were all about 3.7, which was lower than the requirement of AmB-d package insert (pH > 4.2). The number of insoluble particles >10 µm/25 µm in 25 mg/500 ml infusions exceeded China Pharmacopoeia limit. Filters in 25 mg/500 ml infusion set were full of AmB-d after dripping slowly for 6 h, and 331.3 ml solution was left in the bottles and only 11.3% of AmB-d could flow out. Whereas the AmB-d infusion consists of 25 mg/50 ml, 25 mg/250 ml and 50 mg/500 ml could meet with China Pharmacopoeia standards, and they flowed out easily and completely. CONCLUSIONS: In practice, 25 mg/250 ml and 50 mg/500 ml would be more suitable for clinical use, rather than 25 mg/500 ml. We provided a convenient method for AmB-d preparation.

How to define a significant deviation from the expected internal quality control result.

BACKGROUND: Internal quality control (IQC) is an everyday practice described in several documents. Its planning requires the definition of quality goals and a documentation system able to provide alarms as soon as the goals are not reached. We propose the use of the uncertainty approach to develop an effective alarm system. METHODS: The use of the uncertainty information to verify the conformity to specifications is described. A top-down approach to the definition of the uncertainty of the method is described. Once the uncertainty is calculated, the complete measurement result (result ± expanded uncertainty) is compared with the maximum permissible error (quality goal). An alternative and more immediate presentation is obtained defining an "acceptance zone" derived from the maximum permissible error reduced on either sides by expanded uncertainty. This approach is applied to two analytes: glucose and creatinine. RESULTS: The relationship between quality goal and expanded uncertainty defines the width of the acceptance zone; if uncertainty is equal or larger than the quality goal, the goal is not attainable. CONCLUSIONS: The proposed approach uses an information, expanded uncertainty, that each laboratory seeking ISO 15189 accreditation should already have. The data presentation is immediate and easy to interpret allowing a direct comparison between the performance of the method and the quality goals.

Intervalos de referencia de determinaciones bioquímicas en el laboratorio central del Hospital de Trelew / Reference intervals of biochemical determinations in the central laboratory in Trelew Hospital / Intervalos de referencia de determinagóes bioquímicas no laboratorio central do Hospital de Trelew

El objetivo del presente trabajo fue establecer los intervalos de referencia de las determinaciones: glucosa, urea, colesterol, proteínas totales, albúmina, ácido úrico, creatinina, hematocrito y hemoglobina en el Laboratorio Central del Hospital Zonal de Trelew. La población bajo estudio fueron pacientes mayores de 18 años atendidos por consultorio externo entre diciembre de 2008 y marzo de 2009. El estudio fue completado entre marzo y abril de 2011. Las determinaciones se realizaron con un autoanalizador de química clínica Metrolab 2300 plus y un contador hematológico Sysmex 2100. Se comprobó que los valores de las determinaciones se ajustaran a una distribución normal y se realizó el cálculo de los fractiles 0,025 y 0,975 para la obtención del intervalo de referencia (IR) del 95%. En un caso se utilizó transformación logarítmica de los datos y para dos categorías se aplicó el método no paramétrico. Para los valores de referencia inferior y superior se establecieron los intervalos con un 90% de confianza (IC). Los valores de referencia obtenidos fueron: glucosa de 0,74 a 1,07 g/L, urea de 0,19 a 0,51 g/L, colesterol de 1,21 a 2,43 g/L, proteínas totales de 6,45 a 7,99 g/dL, albúmina de 3,62 a 4,61 g/dL, creatinina de 0,57 a 1,10 mg/dL, ácido úrico para el sexo femenino de 18,69 a 51,93 mg/L y para el sexo masculino de 30,50 a 62,92 mg/L, hematocrito para sexo femenino de 37 a 45% y para el sexo masculino de 40 a 50%, hemoglobina para el sexo femenino de 11,70 a 15,17 g/dL y para el sexo masculino de 13,09 a 17,19 g/dL. Los valores de ácido úrico, hematocrito y hemoglobina se separaron por sexo para dar continuidad a la política del laboratorio y de los fabricantes de CAICYTtivos, que consiste en considerar las diferencias existentes entre ambos sexos. Dentro del rango dado por el fabricante se obtuvieron los resultados para glucosa, albúmina y hemoglobina; sobre el mismo, para urea, colesterol, proteínas y ácido úrico y por debajo del mismo para creatinina.

The aim of the present work was to establish the reference intervals of the following determinations, glucose, urea, cholesterol, total proteins, albumin, uric acid, creatinine, hematocrite and hemoglobin in the Central Laboratory of Trelew Zonal Hospital. The population under study was defined as 18-year-old or older patients that came to the laboratory from the ambulatory consulting room since December 2008 to March 2009, and then between March and April 2011. Blood samples were processed with a Metrolab 2300 plus clinical chemistry autoanalyser and a Sysmex 2100 hematological counter. After checking if the result distribution applied to a normal distribution, fractiles 0.025 and 0.975 were calculated to obtain a 95% Reference Interval (RI). In one case, a logarithmic transformation of the results was needed and for two categories a non-parametric method was used. For the upper and lower reference values, the intervals were calculated at 90% confidence (CI) The reference values obtained were; 0.74-1.07 g/L glucose, 0.19-0.51 g/L urea, 1.21-2.43 g/L cholesterol, 6.45-7.99g/dL total proteins, 3.62-4.61 g/dL albumin and 0.57-1.10 mg/dL creatinine, 18.69 - 51.93 mg/L uric acid in women, and 30.50 - 69.92 mg/L in men; 37 - 45% hematocrite in women and 40 - 50% in men; 11.70 - 15.17 g/dL hemoglobin in women and 13.09 - 17.19 g/dL hemoglobin in men. Uric acid, hematocrite and hemoglobin values were calculated according to sex in order to offer concordance with commercial kit and the laboratory policies which consist in considering the significant differences between both sexes. The results obtained for glucose, albumin and hemoglobin were within the reference interval given by the commercial kits; urea, cholesterol, total protein and uric acid were above it; and creatinine reference interval was lower than the reference interval from the commercial kits.

O objetivo do presente trabalho foi estabelecer os intervalos de referencia das determinagóes: glicose, ureia, colesterol, proteínas totais, albumina, ácido úrico, creatinina, hematocrito e hemoglobina no Laboratorio Central do Hospital Zonal de Trelew. A populagao sob estudo foram pacientes de mais de 18 anos atendidos através de consultorio externo entre dezembro do ano 2008 e margo de 2009. O estudo foi completado entre margo e abril de 2011. As determinagóes foram realizadas com um auto-analisador de química clínica Metrolab 2300 plus e um contador hematológico Sysmex 2100. Comprovouse que os valores das determinagóes se ajustaram a uma distribuigao normal e se realizou o cálculo dos quantis 0,025 e 0,975 para a obtengao do intervalo de referencia (IR) de 95%. Num caso foi utilizada transformagao logarítmica dos dados e para duas categorias se aplicou o método nao paramétrico. Para os valores de referencia inferior e superior foram estabelecidos os intervalos com 90% de confianga (IC). Os valores de referencia obtidos foram: glicose de 0,74 a 1,07 gr/L, ureia de 0,19 a 0,51 gr/L, colesterol de 1,21 a 2,43 g/L, proteínas totais de 6,45 a 7,99 gr/dL, albumina de 3,62 a 4,61 gr/dL, creatinina de 0,57 a 1,10 mg/dL, ácido úrico para o sexo feminino de 18,69 a 51,93 mg/L e para o sexo masculino de 30,50 a 62,92 mg/l, hematocrito para sexo feminino de 37 a 45% e para o sexo masculino de 40 a 50%, hemoglobina para o sexo feminino de 11,70 a 15,17 g/dL e para o sexo masculino de 13,09 a 17,19 g/dL. Os valores de ácido úrico, hematocrito e hemoglobina foram separados por sexo para dar continuidade a política do laboratorio e dos fabricantes de reagentes, que consiste em considerar as diferengas existentes entre ambos os sexos. Dentro do intervalo dado pelo fabricante foram obtidos os resultados para glicose, albumina e hemoglobina; superior ao mesmo para ureia, colesterol, proteínas e ácido úrico e inferior ao mesmo para creatinina.

[Validation of pharmaceutical quality of a [6,6-(2)H(2)]-glucose parenteral solution used for insulin-resistance measurement during human clinical trials]. / Validation de la qualité pharmaceutique de préparations de [6,6-(2)H(2)]-glucose en solution aqueuse administrées par voie parentérale pour la mesure de l'insulino-résistance dans le cadre d'essais cliniques.

INTRODUCTION: Deuterated glucose ([6,6-(2)H(2)]-glucose) is a stable isotopic tracer administered parenterally in healthy volunteers, obese or diabetic patients in clinical trial to study glucose metabolism during euglycemic hyperinsulinemic clamps. In accordance with the Health Authorities on drug safety, we evaluated the pharmaceutical quality of this preparation for biomedical research with a stability study. METHODS: After pharmaceutical qualification of the raw material, the [6,6-(2)H(2)]-glucose was dissolved in water for injection, then sterile, filtered under positive pressure of nitrogen and then autoclaved. Two batch products (500mg/10mL and 2g/15mL) were sampled to evaluate glucose alteration, isotope shift, limpidity, apyrogenicity and sterility at regular intervals for 2 years. Deuterated glucose solutions were stored in the dark, at +2°C+8°C, in type II glass bottles. RESULTS: Neither significant decrease of glucose concentration nor pH variation were observed for 2 years. The 5-hydroxymethylfurfural concentration was below the human harmful levels, attesting a non-generation of metabolites during autoclaving. Isotopic enrichment higher than 99% reflected the stability of deuterated label on the 6-carbon of glucose molecules. The non-visible particle concentration below the minimal permissible concentration tolerated by the European Pharmacopoeia and the absence of bacterial endotoxin and bacterial growth attested limpidity, apyrogenicity and sterility of the [6,6-(2)H(2)]-glucose solutions. CONCLUSION: After the 2-year study, 500mg/10mL and 2g/15mL deuterated glucose solutions stored in the dark at +2°C+8°C were stable in aqueous solution, allowing to ensure safety administration for human clinical trials using euglycemic hyperinsulinemic clamps.

Two evaluation budgets for the measurement uncertainty of glucose in clinical chemistry.

BACKGROUND: Measurement uncertainty characterizes the dispersion of the quantity values attributed to a measurand. Although this concept was introduced to medical laboratories some years ago, not all medical researchers are familiar with it. Therefore, the evaluation and expression of measurement uncertainty must be highlighted using a practical example. METHODS: In accordance with the procedure for evaluating and expressing uncertainty, provided by the Joint Committee for Guides in Metrology (JCGM), we used plasma glucose (Glu) as an example and defined it as the measurand. We then analyzed the main sources of uncertainty, evaluated each component of uncertainty, and calculated the combined uncertainty and expanded uncertainty with 2 budgets for single measurements and continuous monitoring, respectively. RESULTS: During the measurement of Glu, the main sources of uncertainty included imprecision, within-subject biological variance (BV(w)), calibrator uncertainty, and systematic bias. We evaluated the uncertainty of each component to be 1.26%, 1.91%, 5.70%, 0.42%, and -2.87% for within-run imprecision, between-day imprecision, BV(w), calibrator uncertainty, and systematic bias, respectively. For a single specimen, the expanded uncertainty was 7.38% or 6.1±0.45 mmol/L (κ=2); in continuous monitoring of Glu, the expanded uncertainty was 13.58% or 6.1±0.83 mmol/L (κ=2). CONCLUSIONS: We have demonstrated the overall procedure for evaluating and reporting uncertainty with 2 different budgets. The uncertainty is not only related to the medical laboratory in which the measurement is undertaken, but is also associated with the calibrator uncertainty and the biological variation of the subject. Therefore, it is helpful in explaining the accuracy of test results.

Wavelet analysis used for spectral background removal in the determination of glucose from near-infrared single-beam spectra.

Wavelet analysis is developed as a preprocessing tool for use in removing background information from near-infrared (near-IR) single-beam spectra before the construction of multivariate calibration models. Three data sets collected with three different near-IR spectrometers are investigated that involve the determination of physiological levels of glucose (1-30 mM) in a simulated biological matrix containing alanine, ascorbate, lactate, triacetin, and urea in phosphate buffer. A factorial design is employed to optimize the specific wavelet function used and the level of decomposition applied, in addition to the spectral range and number of latent variables associated with a partial least-squares calibration model. The prediction performance of the computed models is studied with separate data acquired after the collection of the calibration spectra. This evaluation includes one data set collected over a period of more than 6 months. Preprocessing with wavelet analysis is also compared to the calculation of second-derivative spectra. Over the three data sets evaluated, wavelet analysis is observed to produce better-performing calibration models, with improvements in concentration predictions on the order of 30% being realized relative to models based on either second-derivative spectra or spectra preprocessed with simple additive and multiplicative scaling correction. This methodology allows the construction of stable calibrations directly with single-beam spectra, thereby eliminating the need for the collection of a separate background or reference spectrum.

Standardization and in vivo antioxidant activity of ethanol extracts of fruit and leaf of Piper sarmentosum.

The present study aimed to investigate standardized ethanol extracts of fruit and leaves of Piper sarmentosum for their in vivo antioxidant activity in rats using a CCl (4)-induced oxidative stress model. The standardization was based on the quantification of the markers pellitorine, sarmentine and sarmentosine by high performance liquid chromatography (HPLC), and determination of total primary and secondary metabolites. The rats, divided into 7 groups each (n = 6), were used as follows: group 1 (CCl (4), negative control), group 2 (untreated, control), groups 3 and 4 (fruit extract 250 and 500 mg/kg, respectively), groups 5 and 6 (leaf extract 250 and 500 mg/kg, respectively) and group 7 (vitamin-E 100 mg/kg, positive control). The doses were administered orally for 14 days; 4 h following the last dose, a single dose of CCl (4) (1.5 mg/kg) was given orally to all the groups except group 2, and after 24 h, blood and liver of each animal were obtained. Analysis of plasma and liver homogenate exhibited significant preservation of markers of antioxidant activity, total plasma antioxidant activity (TPAA), total protein (TP), superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid reactive species (TBARS), in the pretreated groups as compared to the CCl (4) group (p < 0.05). Histology of the liver also evidenced the protection of hepatocytes against CCl (4) metabolites in the pretreated groups. The results of this study indicate the IN VIVO antioxidant activity of both extracts of the plant, which may be valuable to combat diseases involving free radicals.

[Quantitative determination of glucose by internal standard laser Raman spectra].

In the present paper we report quantitative analysis of glucose using internal standard laser Raman spectra. A good linear correlation was observed between the intensities of the -COO band at 1 125 cm(-1) using excition wavelength of 632.81 nm (r = 0.998 8) and the glucose concentration over the range 0-1.8 mol x L(-1). Band intensities were normalized against an internal standard (water band at 1 643 cm(-1)), and the limit of detection (L. O. D.) of glucose is 0.022 7 mol x L(-1). The interference ions would not influence the quantitative analysis. When this method was used to determine 5% glucose NaCl, 5% glucose, and 10% glucose injections, the result showed that the recoveries are 71.88%-126.31%, 81.02%-124.89% and 74.87%-121.32%, and the RSDs are 5.44%, 4.34% and 0.94%, respectively. The non destructive, non intrusive nature of the method makes internal standard laser Raman spectra a convenient, accurate, and green quantitative analysis method.

Stability of vancomycin in icodextrin peritoneal dialysis solution.

BACKGROUND: Icodextrin is a glucose polymer used as an alternative osmotic agent in peritoneal dialysis (PD) solutions. There are few data regarding the long-term stability of vancomycin in icodextrin PD solution. OBJECTIVE: To determine the chemical stability of vancomycin in icodextrin PD solution in polyvinyl chloride containers over a 7 day period at 4, 24, and 37 degrees C. METHODS: Study samples were prepared by adding 2000 mg vancomycin HCl to commercially available 2.0 L bags of icodextrin 7.5% PD solution. Nine bags were prepared and stored in the following conditions: 3 under refrigeration (5 degrees C), 3 at room temperature (24 degrees C), and 3 at body temperature (37 degrees C). Samples were withdrawn from each bag immediately after preparation and at predetermined intervals over the subsequent 7 days. Solutions were visually inspected for precipitation, cloudiness, or discoloration at each sampling interval. Total concentration of vancomycin in dialysate fluid was determined by high performance liquid chromatography. RESULTS: Under refrigeration, a mean +/- SD of 99.7% +/- 0.5% of the initial vancomycin concentration remained at 168 hours (7 days). At room temperature, 97.5% +/- 3.4% remained at 168 hours. At body temperature, 94.3% +/- 3.9% remained at 24 hours. Stability was not assessed beyond these time points. CONCLUSIONS: Premixed vancomycin-icodextrin PD solutions, whether stored refrigerated or at room temperature, were found to be stable for up to 7 days. However, we recommend that these solutions be kept refrigerated whenever possible. Solutions stored at body temperature were stable for up to 24 hours, permitting the practice of prewarming solutions prior to administration.

[Analysis of multi-component sugar aqueous solution in low-concentration by near-infrared spectrometry].

Near infrared spectrophotometry was used to determine the concentrations of one, two and three-component sugar aqueous solutions. However, this method was always applied to dry or low moisture products and was not practicable for fresh fruits and vegetables because of the strong absorption of water in near infrared region. In this paper, the authors applied NIR method to aqueous solutions and discussed how to enhance the sensitivity. In aqueous solution systems, concentration of each individual sugar was in range of 0.01-0.25 mol x L(-1). Different calibrations and predicted results were gotten and compared to each other when full spectra or significant spectra regions were considered. By selecting relevant spectra regions due to important structural information to overcome the disturbance from absorption of water, calculations could be optimized and predicted results of concentrations were more accurate regarding the standard error of calibration (SEC) and standard error of prediction (SEP).