Clinical laboratory automated urinalysis: comparison among automated microscopy, flow cytometry, two test strips analyzers, and manual microscopic examination of the urine sediments.

Urinalysis is one of the habitual clinical laboratory procedures, which implies that one of the largest sample volumes currently requires significant labor to examine microscopic sediments. Different analyzers currently used to perform this task have been compared with the manual microscopic sediment examination. The Atlas Clinitek 10 (Bayer Corporation, Diagnostics Division, Tarrytown, NY) and Urisys 2400 (Hitachi Science Systems Ltd., Ibaraki, Japan) test strips analyzers and two automated urinalysis systems, Sysmex UF-100 (Sysmex Corporation Kobe, Japan) and IRIS iQ200 (International Imaging Remote Systems, Chatsworth, CA), have been considered. We assessed the concordance between the results obtained from 652 freshly collected urine samples for erythrocytes (RBC), leukocytes (WBC), squamous epithelial cells (EC), nitrites/bacteria, and crystals using the methodologies mentioned. A principal components analysis was performed in order to examine the correlation between these parameters. Instrument accuracy was also assessed. The Spearman's statistic (p) showed an adequate agreement between methods for RBC (iQ200=0.473; UF-100=0.439; Atlas=0.525; Urisys=0.539), WBC (iQ200=0.695; UF-100=0.761; Atlas=0.684: Urisys=0.620), and bacteria/nitrites (iQ200=0.538; UF-100=0.647; Atlas=0.532; Urisys=0.561) counts. By applying the Wilcoxon and McNemar tests, a concordance degree was found between 82-99 and 52-95% for the values obtained from the two test strips analyzers considered and from the iQ200 and UF-100 systems, respectively. From these results, we can conclude that both test strips analyzers are similar and, on the other hand, that automated urinalysis is needed to improve precision and the response time; but sometimes manual microscopic revisions are required, mainly when flags, because of crystals, are detected.

[Comparison of 2 devices to measure spinal fluid glucose concentration in hyperbaric spinal anesthesia]. / Comparación de dos sistemas de medida de las concentraciones de glucosa en líquido cefalorraquídeo en la anestesia intradural hiperbara.

OBJECTIVES: To compare spinal fluid glucose measurements recorded by the laboratory analyzer Synchron LX20 Pro and the glucometer Ascensia Elite XL during continuous spinal anesthesia after injection of 10 mg of hyperbaric bupivacaine, in order to assess the reliability and speed of the 2 devices for monitoring changes in glucose concentration. PATIENTS AND METHODS: Prospective study of 34 patients under continuous spinal anesthesia administered through a 22-gauge catheter; 9 samples of spinal fluid were extracted from each patient for glucose level measurement. The first extraction was before administration of the anesthetic and the remaining ones were during spinal anesthesia until the end of complete motor block. Correlation was assessed with the Pearson test and agreement with the Bland-Altman method. RESULTS: A total of 241 pairs of measurements were obtained. The correlation was r = 0.96 (P < .01). The mean (SD) difference in measurements from the 2 devices was -1.06 (34.82 mg x dL(-1)). The percentage of variation (systematic error) was -1.9% (11.8%), placing the 95% confidence interval between -25% and 21.2%. CONCLUSIONS: Measurements from the 2 devices are highly correlated. The absolute and percentage systematic error (bias) is negligible. Finding that 95% of measurements are within 23% of the mean seems a fair percentage of error to us. We therefore believe the percentage variation, or systematic error, is clinically acceptable and that either device can be used.

Comparación de dos sistemas de medida de las concentraciones de glucosa en líquido cefalorraquídeo en la anestesia intradural hiperbara / Comparison of 2 devices to measure spinal fluid glucose concentration in hyperbaric spinal anesthesia

OBJETIVOS: Comparar las mediciones de glucorraquia realizadas en el Laboratorio con el autoanalizador Synchron LX20 PRO(R) (Beckman Coulter) con las realizadas con un glucómetro Ascensia EliteXL&Elite(R) durante la anestesia espinal, después de administrar 10 mg de bupivacaína hiperbara para así disponer de un método rápido y fiable al medir las cifras de glucorraquia durante una anestesia espinal continua y seguir su evolución. PACIENTES Y MÉTODOS: Estudio prospectivo de 34 pacientes bajo anestesia espinal continua con un catéter 22 G a través del cual se extrajeron 9 muestras por paciente de líquido cefalorraquídeo para determinar la glucorraquia, la primera antes de la administración del anestésico y los siguientes durante la anestesia espinal hasta el final del bloqueo motor completo. La correlación se midió con el test de Pearson y el grado de concordancia con el método de Bland-Altman. RESULTADOS: Se obtuvieron 241 pares de medidas. El coeficiente de correlación fue de r = 0,96 (p < 0,01). La diferencia media entre los dos métodos fue de –1,06 ± 34,82 mg dL–1. El porcentaje de variación (error sistemático) fue de –1,9 ± 11,8%, situándose el intervalo de confianza del 95% entre el –25% y el 21,2%. CONCLUSIONES: Se obtiene una buena correlación entre ambos métodos. El error sistemático absoluto y porcentual (bias), es despreciable. Encontrar el 95% de los valores con un margen de un 23% sobre la media del error porcentual nos parece razonable, por lo que consideramos la variación porcentual del error sistemático clínicamente aceptable para poder intercambiar ambos métodos de medida

OBJECTIVES: To compare spinal fluid glucose measurements recorded by the laboratory analyzer Synchron LX20 Pro and the glucometer Ascensia Elite XL during continuous spinal anesthesia after injection of 10 mg of hyperbaric bupivacaine, in order to assess the reliability and speed of the 2 devices for monitoring changes in glucose concentration. PATIENTS AND METHODS: Prospective study of 34 patients under continuous spinal anesthesia administered through a 22-gauge catheter; 9 samples of spinal fluid were extracted from each patient for glucose level measurement. The first extraction was before administration of the anesthetic and the remaining ones were during spinal anesthesia until the end of complete motor block. Correlation was assessed with the Pearson test and agreement with the Bland-Altman method. RESULTS: A total of 241 pairs of measurements were obtained. The correlation was r=0.96 (P<.01). The mean (SD) difference in measurements from the 2 devices was –1.06 (34.82 mg·dL-1). The percentage of variation (systematic error) was –1.9% (11.8%), placing the 95% confidence interval between -25% and 21.2%. CONCLUSIONS: Measurements from the 2 devices are highly correlated. The absolute and percentage systematic error (bias) is negligible. Finding that 95% of measurements are within 23% of the mean seems a fair percentage of error to us. We therefore believe the percentage variation, or systematic error, is clinically acceptable and that either device can be used

Relación de los niveles de la glucorraquia con el bloqueo sensitivo y motor durante la anestesia raquídea con bupivacaína hiperbara / Relation between glucose concentrations in cerebrospinal fluid and sensory and motor block during spinal anesthesia with hyperbaric bupivacaine

OBJETIVO: Estudiar la relación de la glucorraquia conel nivel más alto del bloqueo sensitivo y con la duracióndel bloqueo motor después de la administración intratecalde 2 mL de bupivacaína hiperbara. Averiguar lascifras de glucorraquia al finalizar el bloqueo motor.PACIENTES Y MÉTODOS: Estudio prospectivo de 34pacientes bajo anestesia espinal continua con un catéter22 G, a través del cual se extraen muestras de líquidocefalorraquídeo para determinar la glucorraquia a los 5,10, 15, 20, 30, 45, 60 minutos y al final del bloqueomotor. Después de cada extracción se valora el grado delbloqueo motor y durante los primeros 20 minutos elnivel del bloqueo sensitivo.RESULTADOS: Se observa una tendencia descendente delos niveles de glucorraquia desde los 5 minutos (1027,07 ±349,04 mg dL-1), hasta el final del bloqueo motor completo(247,50 ± 20,39 mg dL-1). La probabilidad de no encontrarbloqueo motor con cifras de glucorraquia de 287,5 mgdL-1 o superiores es menor del 5%. Identificamos unacorrelación positiva entre el nivel más alto de bloqueo sensitivoy la duración del bloqueo motor completo (r = 0,62,p < 0,01) y entre las glucorraquias obtenidas en el momentodel nivel más alto de bloqueo sensitivo y al final del bloqueomotor completo (r = 0,50, p <0,01).CONCLUSIÓN: Después de una anestesia espinal continuacon bupivacaína hiperbara, la glucorraquia guardauna relación directa con el nivel más alto de bloqueosensitivo, la evolución y el final del bloqueo motor

OBJECTIVE: To study the relation between cerebrospinalfluid (CSF) glucose levels, the highest level of sensoryblock, and the duration of motor block after intrathecalinjection of 2 mL of hyperbaric bupivacaine. Todetermine CSF glucose levels upon recovery from motorblock.PATIENTS AND METHODS: A prospective study of 34patients administered a spinal anesthetic in continuousinfusion through a 22-gauge catheter. CSF samples wereextracted through the catheter 5, 10, 15, 20, 30, 45, and60 minutes after start of infusion and upon motor recovery.After each extraction the intensity of the motorblock was assessed; the intensity of the sensory blockwas assessed after each extraction up to 20 minutes.RESULTS: Glucose concentrations in CSF tended todecrease from 5 minutes (1027.07 [SD 349.04] mg dL-1)until full motor recovery (247.50 [20.39] mg dL-1). Theprobability not to find a motor block at a CSF glucoseconcentration of 287.5 mg dL-1 or higher was less than5%. We identified a positive correlation between the highestlevel of sensory block and the duration of full motorblock (r=0.62, P<0.01) and between CSF glucose levels atthe moment of greatest sensory block and upon fullmotor recovery (r=0.50, P<0.01).CONCLUSIONS: After continuous spinal anesthesia withhyperbaric bupivacaine, glucose concentrations in CSFare directly related to the highest level of sensory block,the course of the blockade, and its reversal

Efficiency of antidepressant drugs as monoamine reuptake inhibitors: analysis of the hydrophobicity influence using biopartitioning micellar chromatographic data.

The reuptake blockade of biogenic amines by antidepressants is related not only to their therapeutics effects, but also to their side effects and potential drug-drug interactions. As an alternative to classical quantitative structure-activity relationships studies, in this work we propose different quantitative retention-activity relationships (QRAR) models that are able to describe the monoamine reuptake inhibition by antidepressants. The retention of compounds is measured using a biopartitioning micellar chromatography (BMC) system that can simulate the same hydrophobic, electronic and steric molecular interactions as those that condition drug activity. Since all the compounds considered in this work are structurally related because all of them share the same molecular features as the corresponding basic pharmacophore, the results obtained show that there is a retention range in which antidepressants present the highest monoamine reuptake inhibitor potency.

Role of hydrophobicity on the monoamine receptor binding affinities of central nervous system drugs: a quantitative retention-activity relationships analysis using biopartitioning micellar chromatography.

Biological action and activity reflect an aspect of the fundamental physicochemical properties of the bioactive compounds. As an alternative to classical QSAR studies, in this work different quantitative retention-activity relationships (QRAR) models are proposed, which are able to describe the role of hydrophobicity on the binding affinity to different brain monoamine receptors (H(1)-histamine, alpha(1)-noradrenergic and 5-HT(2)-serotonergic) of different families of psychotherapeutic drugs. The retention of compounds is measured in a biopartitioning micellar chromatography (BMC) system using Brij-35 mobile phases. The adequacy of the QRAR models developed is due to the fact that both the retention of compounds in BMC and the drug-receptor interaction are described by the same hydrophobic, electronic and steric properties of compounds. The obtained results indicate that, for structurally related compounds that present the same molecular features as the basic pharmacophore, there is a retention range in which compounds present the highest affinity to all of monoamine receptors.

QRAR models for central nervous system drugs using biopartitioning micellar chromatography.

The capability of biopartitioning Micellar Chromatography, BMC, to describe and estimate pharmacokinetic and pharmacodynamic parameters of central nervous system drugs is reviewed in this article. BMC is a mode of micellar liquid chromatography, MLC, that uses micellar mobile phases of Brij35 (polyoxyethilene(23) lauryl ether) prepared in physiological conditions (pH, ionic strength). The retention of a drug in this system depends on its hydrophobic, electronic and steric properties, which also determine its biological activity. The results of BMC studies suggest that this in vitro approach is an attractive useful tool to be implemented into the lead optimization step of drug development scheme.

Opioid analgetics retention-pharmacologic activity models using biopartitioning micellar chromatography.

Opioids are drugs used in medicine for pain control. In this paper, retention-pharmacokinetics and retention-pharmacodynamics relationships of opioids are proposed and statistically validated. These models are based on the compound retention in the biopartitioning micellar chromatography system (BMC), a new methodology which has successfully been used to develop QRAR models for many other families of compounds. The obtained results are compared to the traditional QSAR models using lipophilicity data. The adequacy of QRAR models is due to the fact that the characteristics of the compounds such as the hydrophobicity, electronic charge and steric effects determine both their retention in BMC and their pharmacokinetic and pharmacodynamic behavior.

Retention pharmacokinetic and pharmacodynamic parameter relationships of antihistamine drugs using biopartitioning micellar chromatography.

Antihistamines are drugs which act by competitive inhibition of the H1 or H2 histamine receptors. Little has been known about their clinical pharmacokinetics and biological responses until the last few years. In this paper, we propose quantitative retention-activity relationship, QRAR, models based on the retention data of antihistamines in a biopartitioning micellar chromatography (BMC) system using a Brij35 mobile phase for describing pharmacokinetic parameters such as half-life and volume of distribution, or the pharmacodynamic parameters, therapeutic plasma levels, lethal doses and drug-receptor dissociation constant. The predictive ability of these models is statistically validated. These results are compared to traditional quantitative structure-activity relationship, QSAR, models using lipophilicity data. The adequacy of QRAR models can be explained taking into account the fact that the retention of compounds in BMC depends on their hydrophobic, electronic and steric characteristics which are of great importance in pharmacokinetic and pharmacodynamic behavior.

An LD50 model for predicting psychotropic drug toxicity using biopartitioning micellar chromatography.

The LD50 determination is the main way to measure the acute toxicity of all types of substances. At the present time, however, there is increasing opposition to the use of living animals in research and testing activities from animal rights groups as well as some scientists. Nevertheless, the need to have a tool for estimating the potential toxicity of new compounds for human consumption has encouraged the development of alternative methods. Under adequate conditions, the partitioning in micellar liquid chromatography can describe the drug biopartitioning. We have named this chromatographic system biopartitioning micellar chromatography (BMC). In this paper, an LD50 QRAR model developed for psychotropic drugs from their retention data in BMC, is described. The model's ability to predict new psychotropic drug toxicity is statistically proved.

Determination of amobarbital and secobarbital in plasma samples using micellar liquid chromatography.

A new liquid chromatographic procedure for the determination of amobarbital and secobarbital in plasma samples is proposed. The method uses a Spherisorb octadecylsilane ODS-2 C(18) analytical column, a guard column of similar characteristics and 0.04 M CTAB solution buffered at pH 7.5 containing 3% 1-propanol as micellar mobile phase. The UV detection was carried out at 250 nm. Butabarbital was used as internal standard. Plasma samples preparation only required adequate dilution with the mobile phase before injection into the chromatographic system. The limits of detection were 0.2 and 0.4 mg/L for amobarbital and secobarbital, respectively. The proposed method allows the determination of amobarbital and secobarbital in plasma at therapeutic levels.

Development of predictive retention-activity relationship models of tricyclic antidepressants by micellar liquid chromatography.

The distribution of tricyclic antidepressants from plasma to brain, where these drugs exert their main clinical action, and other organs is related to transport events across the cell membranes of the different tissues. It could be expected that all the molecular features that condition the transport processes (mainly hydrophobicity and molar total charge) also control the pharmacokinetic and biochemical behavior. Micellar liquid chromatography (MLC) has been proposed to emulate in vitro the partitioning process in the biomembranes. The use of micellar solutions of Brij35 as mobile phases in reversed-phase liquid chromatography has proven to be valid to predict the biological activities of local anesthetics, barbiturates, catecholamines, and benzodiazepines. In this paper, the relationships between the capacity factor in MLC and some pharmacokinetic parameters and biological responses of tricyclic antidepressants are studied. Predictive regression models for the estimation of these parameter values, using the logarithm of the retention data (log k) as independent variable, are also proposed.