A new multiresponse optimization approach in combination with a D-Optimal experimental design for the determination of biogenic amines in fish by HPLC-FLD.

A new strategy to approach multiresponse optimization in conjunction to a D-optimal design for simultaneously optimizing a large number of experimental factors is proposed. The procedure is applied to the determination of biogenic amines (histamine, putrescine, cadaverine, tyramine, tryptamine, 2-phenylethylamine, spermine and spermidine) in swordfish by HPLC-FLD after extraction with an acid and subsequent derivatization with dansyl chloride. Firstly, the extraction from a solid matrix and the derivatization of the extract are optimized. Ten experimental factors involved in both stages are studied, seven of them at two levels and the remaining at three levels; the use of a D-optimal design leads to optimize the ten experimental variables, significantly reducing by a factor of 67 the experimental effort needed but guaranteeing the quality of the estimates. A model with 19 coefficients, which includes those corresponding to the main effects and two possible interactions, is fitted to the peak area of each amine. Then, the validated models are used to predict the response (peak area) of the 3456 experiments of the complete factorial design. The variability among peak areas ranges from 13.5 for 2-phenylethylamine to 122.5 for spermine, which shows, to a certain extent, the high and different effect of the pretreatment on the responses. Then the percentiles are calculated from the peak areas of each amine. As the experimental conditions are in conflict, the optimal solution for the multiresponse optimization is chosen from among those which have all the responses greater than a certain percentile for all the amines. The developed procedure reaches decision limits down to 2.5 µg L-1 for cadaverine or 497 µg L-1 for histamine in solvent and 0.07 mg kg-1 and 14.81 mg kg-1 in fish (probability of false positive equal to 0.05), respectively.

Pareto-optimal front as a tool to study the behaviour of experimental factors in multi-response analytical procedures.

This work presents a methodology to analyse the behaviour of an analytical procedure, above all when optimization of the procedure is needed. The methodology starts by the design of an experiment suitable to fit response surfaces to some analytical responses of interest in the problem being studied. Then, a pareto-optimal front is estimated that accounts for the optimal possibly trading-off solutions among the responses. The analysis of the behaviour of the optimal values of the response surfaces and the experimental conditions that provide these values allows going deeply into the analytical procedure.

[Respiratory morbidity after hospital discharge in premature infants born at < or = 32 weeks gestation with bronchopulmonary dysplasia]. / Morbilidad respiratoria tras el alta hositalaria en prematuros (< or = 32 semanas) con displasia broncopulmonar.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is the most frequent cause of respiratory morbidity in the first 2 years of life among preterm infants who survive the first 28 days. OBJECTIVES: To evaluate respiratory morbidity in the first 2 years of life in a group of preterm infants born at (32 weeks' gestation with BPD (oxygen requirement at 36 weeks' postconceptional age) by comparing it with that in preterm infants born at (32 weeks without BPD and with a control group of full term infants without neonatal morbidity. To determine whether respiratory morbidity in children with BPD decreases after the age of 2 years. PATIENTS AND METHOD: Group I: preterm children with BPD (n = 29). Group II: preterm children without BPD (n = 29). Group III: children with appropriate gestational age and weight (n = 32). A cross-sectional, descriptive study of the three groups was performed over a 2-year period. In 17 children in group 1, the study was prolonged to the age of 4 years. We analyzed wheezing on at least two occasions, use of inhaled bronchodilators, use of inhaled glucocorticosteroids for more than 6 months, and hospitalization for respiratory illness. The chi-square test and Fischer's exact test were performed. RESULTS: At least one episode of wheezing occurred in 25 children (86.2%) in group I compared with 12 children (41.4%) in group II and 6 (18.8%) in group III. Nineteen children (65.5%) in group I and none in the remaining two groups received treatment with inhaled glucocorticosteroids for more than 6 months (p < 0.001). Inhaled bronchodilators were used by 25 children (86.2%) in group I compared with 12 (41.4%) in group II and 6 (18.8%) in the control group (p < 0.001). Twelve children (41.3%) in group I were hospitalized for respiratory illness compared with 8 (27.6%) in group II. There were no admissions among the control group. None of the children with BPD who received prophylaxis with palivizumab contracted respiratory syncytial virus infection. Seventeen children with BPD were evaluated until the age of 4 years. Episodes of wheezing decreased from 88.2% in the first year to 41 % between the third and fourth years (p < 0.001). Treatment with inhaled glucocorticosteroids for more than 6 months was given to 88.2% in the first year, 41.2 % between the first and second year and to 0 % after the second year (p < 0.001). Hospital admissions for respiratory illness decreased from 52.9% in the first year to 17.6% in the second year. None of the children were hospitalized after the age of 2 years (p < 0.001). CONCLUSIONS: During the first 2 years of life, children with BPD showed a greater number of admissions and episodes of wheezing and a greater need for medical treatment. Respiratory morbidity improved with age, 40% showed recurrent wheezing episodes at the age of 4 years.

Morbilidad respiratoria tras el alta hospitalaria en prematuros (32 semanas) con displasia broncopulmonar / Respiratory morbidity after hospital discharge in premature infants born at<= 32 weeks´ gestation with bronchopulmonary dysplasia

Antecedentes: La displasia broncopulmonar es la causa más frecuente de morbilidad respiratoria en los primeros 2 años en el niño pretérmino que sobrevive a los 28 días de vida. Objetivos: Valorar la morbilidad respiratoria durante los primeros 2 años de vida en un grupo de niños pretérmino (>=32 semanas) con displasia broncopulmonar (necesidad de oxígeno a las 36 semanas de edad posconcepcional), comparándola con la de niños pretérmino (<=32 semanas) sin displasia broncopulmonar y con un grupo control de nacidos a término sin enfermedad neonatal. Comprobar si la morbilidad respiratoria en los niños con displasia broncopulmonar disminuye a partir de los 2 años de edad. Pacientes y método: Grupo I: niños pretérmino con displasia broncopulmonar (n=29). Grupo II: niños pretérmino sin displasia broncopulmonar (n=29). Grupo III: niños de peso y edad gestacional adecuados (n=32). En los 3 grupos se realizó estudio longitudinal descriptivo durante 2 años, y en 17 niños del grupo I se realizó el mismo estudio hasta la edad de 4 años. Se analizaron las siguientes variables: sibilancias en al menos dos ocasiones, empleo de broncodilatadores inhalados, utilización de glucocorticoides inhalados durante más de 6 meses, ingresos hospitalarios por problemas respiratorios mediante test de chi cuadrado (X2) y test de Fischer. Resultados: Tuvieron algún episodio de sibilancias 25 niños del grupo I (86,2 por ciento) frente a 12 (41,4 por ciento) del grupo II y 6 (18,8 por ciento) del grupo III. Fueron tratados con glucocorticoides inhalados durante más de 6 meses, 19 niños del primer grupo (65,5 por ciento) y ninguno de los otros 2 grupos (p < 0,001). Utilizaron broncodilatadores inhalados 25 niños del grupo I (86,2 por ciento) frente a 12 (41,4 por ciento) del grupo II y 6 (18,8 por ciento) del grupo control (p < 0,001). Fueron hospitalizados por problemas respiratorios 12 niños del grupo I (41,3 por ciento) frente a 8 (27,6 por ciento) del grupo II, sin que ingresara ninguno del grupo control. De los niños con displasia broncopulmonar que recibieron profilaxis con palivizumab ninguno tuvo infección demostrada por virus respiratorio sincitial (VRS).Se evaluaron hasta los 4 años de edad 17 niños con displasia broncopulmonar. Los episodios de sibilancias disminuyeron del 88,2 por ciento en el primer año al 41 por ciento entre el tercer y cuarto años (p < 0,001). Recibieron tratamiento con glucocorticoides inhalados durante más de 6 meses el 88,2 por ciento en el primer año, el 41,2 por ciento entre el primer y segundo años y ninguno a partir del segundo año (p < 0,001).Los ingresos hospitalarios por problemas respiratorios descendieron del 52,9 por ciento en el primer año al 17,6 por ciento en el segundo, y ningún niño necesitó ingreso a partir de los 2 años (p < 0,001). Conclusiones: Durante los primeros 2 años, los niños con displasia broncopulmonar tienen mayor número de ingresos, más episodios de sibilancias y más necesidad de tratamiento médico; mejoran con la edad, aunque a los 4 años el 40 por ciento tienen episodios repetidos de sibilancias (AU)

[Neonatal candidiasis and liposomal amphotericin B treatment: our experience]. / Candidiasis neonatales y tratamiento con anfotericina B liposomal: nuestra experiencia.

OBJECTIVE: Nosocomial Candidiasis in low birth weight (LBW) infants have increased. Toxic side effects limit the use of conventional Amphotericin B for treatment of fungal infections. The liposomal forms have lowered this risk considerably, even at higher doses. Our aim was to evaluate treatment response to liposomal Amphotericin B in neonates with Candidiasis. PATIENTS AND METHODS: Fifteen neonates diagnosed both clinically and biologically of Candidiasis infection and who were treated with liposomal Amphotericin B from June 1994 through July 1997 were included. Duration of treatment, when culture became negative, secondary effects, complications, other medication, basal pathology and clinical course were analyzed. RESULTS: Mean gestational age was 36 +/- 6 weeks and 60% were preterm. Mean age at diagnosis was 13.4 days. Eleven patients presented sepsis (1 C. Sp., 9 C. albicans and 1 C. parapsilosis). They were treated with liposomal Amphotericin B, starting dose 0.5-1 mg/kg/day). One patient had associated 5-fluorocytosine. Cultures became negative at approximately 13 days and mean duration of therapy was 21.13 days. Seven patients showed additional bacterial infections. Side effects during treatment were anemia and hypotension. CONCLUSIONS: Liposomal Amphotericin B has been effective in the treatment of Candidiasis without toxic signs that can be attributed solely to the medication.

An optimization procedure for determination of indomethacin and acemethacin by differential pulse adsorptive stripping voltammetry. Application on urine samples.

Procedures for the determination of indomethacin and acemethacin by differential pulse adsorptive stripping voltammetry with a mercury electrode have been described and optimised. The selection and optimization of the experimental parameters was done using factorial and central composite designs. Indomethacin and acemethacin in urine were determined by this method with good results and without the need for tedious prior separation. For routine calibration and calculation of the 'capacity to detect', the robust regression method least median squares (LMS) has been proposed.