Rare earth elements recovery from secondary wastes by solid-state chlorination and selective organic leaching.

Processing of end-of-life products (EoL) containing rare earth elements (REE) has gained increasing importance in recent years with the aim of avoiding supply risks. In addition, circular economy renders complete recirculation of technology metals mandatory. Fluorescent lamp wastes are an important source for REE recovery since they contain significant amounts, up to 55 wt%, of Y and Eu in red phosphors. For these purposes, solid-state chlorination (SSC) is an economically attractive alternative to wet acid leaching treatment, which profits from a considerable reduction of chemicals consumption and process costs. Chlorination takes place with dry HCl(g) produced from thermal decomposition of NH4Cl(s), not only converting the REE content of the Hg-free phosphor waste into water soluble REE metal chlorides, but also avoiding the implications of aqueous complex chemistry of REE. To establish an industrial process viable on a commercial scale, the SSC process has been optimized by (i) using a design of experiment (DOE) varying temperature, residence time, and gNH4Cl/gsolid ratio and (ii) improved leaching of the chlorinated metals with an organic mixture selective for REE. As a result, 95.7% of the Y and 92.2% of the Eu were selectively recovered at 295.9 °C, 67 min and a ratio of 1.27 gNH4Cl/gsolid, followed by quantitative selective leaching of the REE. Owed to its low chemicals consumption and operation costs, the current process allows for valorizing lamp waste even when raw material prices are low.

Rare earths separation from fluorescent lamp wastes using ionic liquids as extractant agents.

Processing of end-of-life products has become essential in the rare earth elements (REEs) recovery field because the demand for these metals has increased over the last years due to their intensive use in advanced technologies. Fluorescent lamp wastes are considered one of the most interesting end-of-life products for investigation due to their high REEs content, mainly yttrium and europium. As a result, red phosphors (Y2O3:Eu3+ - YOX) have been chosen for evaluating their REEs' recovery potential. The REEs from a YOX reach liquor, coming from a soft leaching process have been precipitated adding oxalic acid and calcined to get the REEs in oxide form. Cyanex 572, D2EHPA and the ionic liquids, Primene 81R·Cyanex 572 IL and Primene 81R·D2EHPA IL, have been chosen to investigate the efficiency of REEs separation in chloride media. Yttrium, europium and cerium have been individually recovered by a four stages cross-flow solvent extraction process using the Primene 81R·D2EHPA IL and the Primene 81R·Cyanex 572 IL as extractants. Ce(III), Eu(III) and Y(III) have been obtained at high purities ≥ 99.9%. 4 mol/L HCl has been used to recover the yttrium and the europium from the organic phases.

Neodymium recovery from NdFeB magnet wastes using Primene 81R·Cyanex 572 IL by solvent extraction.

The necessity of Rare Earth Elements (REEs) recycling is crucial to minimizing their supply risk and provide an alternative to greener technologies. Hence, the REEs recovery from NdFeB magnet wastes using cationic extractants by solvent extraction technique has been investigated in this research. Due to the difficulty in maintaining the aqueous pH in the industrial counter-current devices when extractants like Cyanex 272 or Cyanex 572 are used, the Primene 81R·Cyanex 572 ionic liquid has been synthesised to overcome this. 99.99% Nd(III) recovery with a purity of 99.7% from an aqueous mixture of Nd/Tb/Dy in chloride medium, the three representative REEs present in the NdFeB magnets wastes, has been achieved after two stages counter-current extraction process using 0.30 M of Primene 81R·Cyanex 572 ionic liquid (1:4 A:O ratio) diluted in Solvesso 100, without any aqueous pH conditioning.

Fusion of genomic, proteomic and phenotypic data: the case of potyviruses.

Data fusion has been widely applied to analyse different sources of information, combining all of them in a single multivariate model. This methodology is mandatory when different omic data sets must be integrated to fully understand an organism using a systems biology approach. Here, a data fusion procedure is presented to combine genomic, proteomic and phenotypic data sets gathered for Tobacco etch virus (TEV). The genomic data correspond to random mutations inserted in most viral genes. The proteomic data represent both the effect of these mutations on the encoded proteins and the perturbation induced by the mutated proteins to their neighbours in the protein-protein interaction network (PPIN). Finally, the phenotypic trait evaluated for each mutant virus is replicative fitness. To analyse these three sources of information a Partial Least Squares (PLS) regression model is fitted in order to extract the latent variables from data that explain (and relate) the significant variables to the fitness of TEV. The final output of this methodology is a set of functional modules of the PPIN relating topology and mutations with fitness. Throughout the re-analysis of these diverse TEV data, we generated valuable information on the mechanism of action of certain mutations and how they translate into organismal fitness. Results show that the effect of some mutations goes beyond the protein they directly affect and spreads on the PPIN to neighbour proteins, thus defining functional modules.

Characterization and performance of carbonaceous materials obtained from exhausted sludges for the anaerobic biodecolorization of the azo dye Acid Orange II.

This work presents the preliminary study of new carbonaceous materials (CMs) obtained from exhausted sludge, their use in the heterogeneous anaerobic process of biodecolorization of azo dyes and the comparison of their performance with one commercial active carbon. The preparation of carbonaceous materials was conducted through chemical activation and carbonization. Chemical activation was carried out through impregnation of sludge-exhausted materials with ZnCl2 and the activation by means of carbonization at different temperatures (400, 600 and 800°C). Their physicochemical and surface characteristics were also investigated. Sludge based carbonaceous (SBC) materials SBC400, SBC600 and SBC800 present values of 13.0, 111.3 and 202.0m(2)/g of surface area. Biodecolorization levels of 76% were achieved for SBC600 and 86% for SBC800 at space time (τ) of 1.0min, similar to that obtained with commercial activated carbons in the continuous anaerobic up-flow packed bed reactor (UPBR). The experimental data fit well to the first order kinetic model and equilibrium data are well represented by the Langmuir isotherm model. Carbonaceous materials show high level of biodecolorization even at very short space times. Results indicate that carbonaceous materials prepared from sludge-exhausted materials have outstanding textural properties and significant degradation capacity for treating textile effluents.

Auditory steady state response in sound field.

OBJECTIVE: Physiological and behavioral responses were compared in normal-hearing subjects via analyses of the auditory steady-state response (ASSR) and conventional audiometry under sound field conditions. DESIGN: The auditory stimuli, presented through a loudspeaker, consisted of four carrier tones (500, 1000, 2000, and 4000 Hz), presented singly for behavioral testing but combined (multiple frequency technique), to estimate thresholds using the ASSR. STUDY SAMPLE: Twenty normal-hearing adults were examined. RESULTS: The average differences between the physiological and behavioral thresholds were between 17 and 22 dB HL. The Spearman rank correlation between ASSR and behavioral thresholds was significant for all frequencies (p < 0.05). Significant differences were found in the ASSR amplitude among frequencies, and strong correlations between the ASSR amplitude and the stimulus level (p < 0.05). CONCLUSIONS: The ASSR in sound field testing was found to yield hearing threshold estimates deemed to be reasonably well correlated with behaviorally assessed thresholds.

Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier.

This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H(n)CdCl((2+n)) species and the formation of H(n)CdCl((2+n))L(q) complexes in the organic phase, where n=0, 1, 2 and q=1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

Immobilisation of horseradish peroxidase on EupergitC for the enzymatic elimination of phenol.

In this study, three different approaches for the covalent immobilisation of the horseradish peroxidase (HRP) onto epoxy-activated acrylic polymers (EupergitC) were explored for the first time, direct HRP binding to the polymers via their oxirane groups, HRP binding to the polymers via a spacer made from adipic dihydrazide, and HRP binding to hydrazido polymer surfaces through the enzyme carbohydrate moiety previously modified by periodate oxidation. The periodate-mediated covalent immobilisation of the HRP on hydrazido EupergitC was found to be the most effective method for the preparation of biocatalysts. In this case, a maximum value of the immobilised enzyme activity of 127 U/g(support) was found using an enzyme loading on the support of 35.2mg/g(support). The free and the immobilised HRP were used to study the elimination of phenol in two batch reactors. As expected, the activity of the immobilised enzyme was lower than the activity of the free enzyme. Around 85% of enzyme activity is lost during the immobilisation. However, the reaction using immobilised enzyme showed that it was possible to reach high degrees of phenol removal (around 50%) using about one hundredth of the enzyme used in the soluble form.

Combining fetal nuchal fold thickness with second-trimester biochemistry to screen for trisomy 21.

OBJECTIVE: To assess second-trimester screening for trisomy 21 by combining ultrasound nuchal fold (NF) measurement with maternal serum biochemistry. METHODS: NF, maternal serum alpha-fetoprotein (AFP) and free beta-human chorionic gonadotropin (beta-hCG) were determined concurrently at 14-19 weeks' gestation in a study population comprising 1813 women with singleton pregnancies, including 1257 unselected women undergoing serum screening for trisomy 21 (1999-2002), and 556 high-risk pregnancies prior to amniocentesis (2003-2005), 402 of whom had positive serum screening tests. The results were expressed in multiples of the gestation-specific normal median (MoMs). RESULTS: There were 1799 unaffected singleton pregnancies, and their NF values approximately fitted a log Gaussian distribution over a wide range. There was a weak but statistically significant correlation between log NF and log AFP (r = - 0.069, P < 0.005) and the correlation coefficient between log NF and log free beta-hCG was even smaller and not statistically significant (r = 0.038, P = 0.11). Among the seven trisomy 21 pregnancies, the median NF level was 1.53 MoM (geometric mean 1.75 MoM), a highly statistically significant increase compared with unaffected pregnancies (P < 0.0001, one-tail Wilcoxon Rank Sum Test). In pregnancies referred because of positive serum screening tests (391 unaffected, seven cases of trisomy 21, one of monosomy X and three other chromosomal anomalies) the use of NF to modify the serum screening risk would have reduced the invasive procedures in unaffected pregnancies by 46% without affecting the detection rate of trisomy 21 or other anomalies. Statistical modeling predicted that adding NF to AFP and free beta-hCG would increase detection more than would adding unconjugated estriol as well as inhibin-A, an analyte that is difficult to measure with precision. CONCLUSIONS: The addition of NF measurement to second-trimester biochemical markers improves screening performance, and could overcome drawbacks in the implementation of inhibin-A assay in clinical practice.

Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.

Long-term efficacy and tolerability of flutamide combined with oral contraception in moderate to severe hirsutism: a 12-month, double-blind, parallel clinical trial.

OBJECTIVE: Our objective was to test the efficacy and tolerability of three doses of flutamide (125, 250, and 375 mg) combined with a triphasic oral contraceptive (ethynylestradiol/levonorgestrel) during 12 months to treat moderate to severe hirsutism in patients with polycystic ovary syndrome or idiopathic hirsutism. DESIGN: We conducted a randomized, double-blind, placebo-controlled, parallel clinical trial. PATIENTS: A total of 131 premenopausal women, suffering from moderate to severe hirsutism, were randomized to placebo or 125, 250, or 375 mg flutamide daily associated with a triphasic oral contraceptive pill. Hirsutism (Ferriman-Gallwey), acne and seborrhea (Cremoncini), and hormone serum levels were monitored at baseline and at 3 (except hormone serum levels), 6, and 12 months. Side effects and biochemical, hematological, and hepatic parameters were assessed. METHODS: We used three-way ANOVA (subject, dose, and visit) with Scheffé adjustment for multiple comparisons or nonparametrical Friedman test and least-squares mean (paired data) and Kruskall-Wallis test for unpaired data analyses. We used chi(2) or Fisher's test for categorical data. RESULTS: A total of 119 patients were included in the intention-to-treat analysis. All flutamide doses induced a significant decrease in hirsutism, acne, and seborrhea scores after 12 months compared with placebo without differences among dose levels. Similar related side effects were observed with placebo and 125 mg flutamide (12.5%), and slightly higher with 250 mg (17.3%) and 375 mg (21.2%). No statistically significant differences were observed either among doses or compared with placebo. CONCLUSIONS: Flutamide at 125 mg daily during 12 months was the minimum effective dose to diminish hirsutism in patients with polycystic ovary syndrome or with idiopathic hirsutism.

Técnicas diagnósticas más utilizadas para la identificación temprana de las pérdidas auditivas / Diagnostics tests more used in the early detection of hearing losses

Las pérdidas auditivas en la infancia afectan al desarrollo emocional del lenguaje y del niño, así como su adaptación al medio social y familiar. Estos efectos adversos pueden evitarse si el diagnóstico de las pérdidas auditivas, y el inicio del tratamiento y la rehabilitación, se establecen antes de los 6 meses de edad. Para la detección temprana de las pérdidas auditivas se han empleado técnicas diversas, tanto subjetivas (basadas en respuestas conductuales a estímulos sonoros), como objetivas (que utilizan respuestas fisiológicas). Actualmente, las más efectivas y confiables son las otoemisiones acústicas y los potenciales evocados auditivos de tronco cerebral. Numerosos grupos de investigadores, en todo el mundo, trabajan arduamente en la búsqueda de una técnica diagnóstica ideal. Recientemente, algunos autores han propuesto la aplicación de la técnica de los potenciales evocados auditivos de estado estable, como una nueva alternativa diagnóstica en la detección temprana de las pérdidas auditivas, y la utilizan en el contexto de un programa de cribado auditivo. En este artículo, se revisan las principales ventajas y desventajas de cada uno de estos procedimientos, así como los principales resultados, en términos de sensibilidad y especificidad, que se han obtenido al utilizarlos en los programas de cribado auditivo

Hearing impairment in early infancy has been linked with lifelong deficits in speech and language acquisition, personal-social maladjustments, and emotional difficulties. Early identification of hearing loss and appropriate intervention within the first 6 months of life has been demonstrated to prevent many of these adverse consequences. There are several available techniques which can reliably identify hearing impairments. The most frequently used are behavioral techniques, otoacoustic emissions, click auditory brainstem response and automated auditory brainstem response. Numerous groups of investigators worldwide work arduously in the search of an ideal diagnostic test. Recently, the multiple auditory steady state responses have been proposed as a new tool in the identification of hearing losses. Also, there are some initial studies focused on developing the technique for hearing screening protocol. The main advantages and disadvantages of each one of these techniques are described. The main results of test performance in terms of sensibility and specificity in a hearing screening context are discussed

Evolución del cribado ecográfico prenatal de defectos congénitos y su impacto sobre los sistemas de información / Evolution of the prenatal ultrasound screening of birth defects and its impact on information systems

Introducción. La ecografía obstétrica es el método más utilizado en el cribado prenatal de defectos congénitos (DC), con resultados muy dispares en cuanto a su efectividad. Los objetivos de este artículo son describir la evolución de la tasa de detección prenatal (TDP) de DC mediante ecografía obstétrica en Barcelona durante el período 1992-1999 y, por otra parte, sugerir un método para evitar el sesgo producido por la propia evolución de los métodos de diagnóstico prenatal cuando comparamos diferentes períodos. Métodos. Entre 1992 y 1999 el Registro poblacional de Defectos Congénitos de Barcelona detectó 1.976 casos (1.462 recién nacidos [RN] y 514 interrupciones voluntarias del embarazo) entre 99.753 gestaciones. Se calcula la TDP de una serie de defectos congénitos aislados agrupados por sistemas anatómicos. En algunos de estos grupos se observa un incremento de la prevalencia, motivo por el que se sugiere una corrección de sus TDP. Resultados. Se registra un incremento de la prevalencia de defectos congénitos aislados de órganos internos (sistema nervioso, respiratorio, digestivo y urinario). Una vez corregidas las TDP de estos grupos se observa un incremento de las TDP globales de todos los grupos de DC aislados, excepto del cardiovascular. Conclusiones. El aparente incremento de las prevalencias observadas de ciertos grupos de DC se debe probablemente a la mejora de los métodos de detección prenatal. Los registros poblacionales están en disposición de medir el impacto de estas variaciones y evitar los sesgos que provocan al comparar diferentes períodos (AU)

Introduction. Obstetrical ultrasound is the most common method to screen for birth defects, showing a great variation in its reported effectivity. The aim of this study is to assess the evolving trends in prenatal ultrasound detection of birth defects and to suggest a method to avoid the bias produced by an increasing detection rate, when comparing different periods of time. Methods. In the population-based Registry of Birth Defects of Barcelona, 1,976 birth defects cases (1,462 newborns and 514 terminations of pregnancy) were detected among 99,753 pregnancies, from 1992 to 1999. Detection rates for isolated birth defects by anatomical systems was evaluated. Since an increasing prevalence was observed in some birth defects systems, adjustment for detection rate was suggested. Results. A rise in the prevalence was observed in isolated birth defects involving internal organs (central nervous system, respiratory, digestive, and urinary). After adjustment in these groups, ultrasound detection rate was found to increase in all system groups of isolated birth defects along the study period, but for the cardiovascular defects. Conclusions. The apparent rise in observed prevalences of certain birth defects may be largely due to the improvements in the prenatal detection methods. Population- based registries are able to measure this impact of evolving prenatal diagnosis, to avoid biases in comparing different periods

Cribado de trisomía 21 en el primer trimestre mediante test combinado de bioquímica y ecografía. Estudio prospective de intervención / First trimester screening for trisomy 21 with the use of the biochemistry-ultrasound combined test. A prospective intervention trial

Objetivo: Evaluar la efectividad del Test Combinado (bioquímica y ecografía en el primer trimestre) para la detección prenatal del síndrome de Down en la población general. Material y métodos: Se determinaron los marcadores bioquímicos de primer trimestre (proteína plasmática A asociada al embarazo y fracción libre de la gonadotropina coriónica) en suero materno a las 7-12 semanas. La translucencia nucal fetal y la edad gestacional se determinaron mediante ecografía a las 10-14 semanas. Se estimó el riesgo combinado el mismo día de la ecografía y se ofreció el diagnóstico citogenético mediante biopsia de corion si el riesgo era de 1:250 o superior. Resultados: La edad gestacional media en la determinación bioquímica fue de 9,5 semanas y de 12,1 para la ecografía. En las 4.447 gestaciones estudiadas con seguimiento completo, los índices de detección fueron del 91% (10/11) para la trisomía 21 y del 83% (5/6) para la trisomía 18 o 13, con una tasa de falsos positivos del 3,8% (167/4.423). Conclusión: El Test Combinado, al determinar los valores de marcadores bioquímicos y de translucencia nucal en intervalos gestacionales óptimos durante el primer trimestre, mostró una tasa de detección del 91% para la trisomía 21 con una reducción en la tasa de falsos positivos al 3,8%

Objetive: To assess the efectiveness of the Combined Test (first-trimester biochemistry and ultrasound) in the prenatal detection of Down syndrome in the general pregnant population. Material and methods: First-trimester biochemical markers (pregnancy associated plasma protein-A and free -hCG) were determined in maternal serum at 7-12 weeks. Nuchal translucency and the gestational age were assessed in a 10-14 weeks scan. The estimated combined risk was delivered the same day of the scan, and when it was 1:250 or above, cytogentic diagnosis was offered by means of chorion villus sampling. Results: The mean gestational age at biochemistry was 9.5 weeks and 12.1 for ultrasound. In the 4,447 studied pregnancies with a complete follow-up, detection rate for trisomy 21 was 91% (10/11), 83% (5/6) for trisomies 18-13, with a 3.8% (167/4423) false-positive rate. Conclusion: The Combined Test, with the assessment of biochemical markers and nuchal translucency in their optimal gestational periods during the first trimester, showed a 91% detection rate for trisomy 21 with a reduced false-positive rate of 3.8%

Transfusión intravascular fetal en el tratamiento de la isoinmunización / Fetal intravascular transfusión in the treatment of alloimmunization

Objetivo: Evaluar los resultados de la transfusión fetal intravascular en el tratamiento de la isoinmunización, durante el período 1990-2003. Sujetos y métodos: Se ofreció una cordocentesis para realizar un hemograma fetal a las gestantes isoinmunizadas con sospecha de anemia fetal significativa. Se practicó transfusión intrauterina cuando el valor del hematocrito fetal fue inferior a -2 desviaciones estándar para la edad gestacional. Las transfusiones se repitieron aproximadamente cada 3 semanas hasta la semana 34-35. Resultados: Se practicó una cordocentesis en 32 gestaciones, en 11 (34%) de las cuales no se objetivó una anemia fetal significativa de acuerdo con los criterios establecidos. En 19 gestaciones se realizaron un total de 50 transfusiones entre las 21 y 35 semanas. No se observó ninguna pérdida fetal espontánea. A los 0-13 años de vida, todos los niños presentan una evolución correcta para su edad. Conclusión: La transfusión intravascular fetal es una técnica efectiva en el tratamiento prenatal de la anemia fetal con resultados favorables a largo plazo

Objective: To assess perinatal outcome after fetal intravascular transfusion in the treatment of alloimmunization between 1990 and 2003. Subjects and methods: Fetal blood sampling was offered to immunized pregnant women when significant fetal anemia was suspected. Intravascular fetal transfusion was performed when the fetal hematocrit was below -2 standard deviations for gestational age. Serial transfusions were scheduled every 3 weeks until approximately 34-35 weeks. Results: Cordocentesis was performed in 32 singleton pregnancies. In 11 (34%) of these, no fetal anemia as defined by the established criteria was detected. Fifty intravascular fetal transfusions were performed in 19 pregnancies, from the 21st to the 35th week. No spontaneous fetal losses were observed. At 0-13 years of age, all the children showed normal development for their age. Conclusion: Fetal intravascular transfusion is an effective procedure in the prenatal treatment of fetal anemia with favorable long-term outcome

Cribado bioquímico y ecográfico de aneuploidía fetal en el segundo trimestre de la gestación / Biochemical and ultrasonographic screening for fetal aneuploidy in the second trimester of pregnancy

Objetivo: Estudio de la efectividad del cribado bioquímico y ecográfico en el segundo trimestre de la gestación para la detección prenatal de trisomía 21 en población de bajo riesgo de aneuploidía. Método: Estudio prospectivo de intervención de 8.894 gestaciones únicas de bajo riesgo de aneuploidía. Se realizó ecografía y extracción simultánea de sangre materna para determinación de alfafetoproteína (AFP) y fracción Beta de la gonadotropina coriónica (Beta-hCG) entre las 14 y 18 semanas. Se consideró como criterio de riesgo para ofrecer amniocentesis una estimación de riesgo superior a 1/270 combinando la edad materna y los valores de marcadores bioquímicos, valores séricos de AFP <= 0,4 múltiplos de la mediana (MoM), de Beta-hCG <= 0,2 MoM (riesgo de trisomía 18), o pliegue nucal superior al percentil 95 para la edad gestacional. Resultados: Las tasas de detección para la trisomía 21 fueron las siguientes: 65 por ciento para la bioquímica y edad materna (con un 11 por ciento de falsos positivos) y 45 por ciento para el pliegue nucal (con 5,3 por ciento de falsos positivos). Los resultados obtenidos con la aplicación de los criterios de riesgo proporcionados indistintamente por cualquiera de ambos parámetros, bioquímica o pliegue nucal, mostraron una tasa de detección del 75 por ciento con una tasa del 14,9 por ciento de falsos positivos. Conclusión: La aplicación simultánea e independiente de los marcadores bioquímicos (AFP y Beta-hCG) y del pliegue nucal para la estimación del riesgo de trisomía 21 en el segundo trimestre permitió detectar el 75 por ciento de fetos afectados, con una tasa de falsos positivos del 14,9 por ciento (AU)

Electroaudiometría con potenciales evocados auditivos en pacientes sordociegos / Auditory evoked potentials electroaudiometry in deafblind patients

La sordoceguera es una discapacidad única caracterizada por una deprivación multisensorial de los sistemas auditivo y visual. La mayoría de la población sordociega presenta capacidades sensoriales residuales, que si se aprovechan adecuadamente constituyen una herramienta fundamental en su rehabilitación. En este trabajo se propone la utilización de los potenciales evocados auditivos (PEA) como una alternativa válida para poner de manifiesto de manera objetiva las capacidades auditivas residuales en pacientes sordociegos. Se estudiaron seis adolescentes (edad promedio: 13 años) con sordoceguera congénita, lesión cerebral y pérdidas auditivas severas, profundas o ambas. Con el sistema AUDIX se exploraron respuestas auditivas (vía aérea) transitorias, y de estado estable multifrecuencia como una combinación de cuatro tonos modulados en amplitud (95 por ciento de profundidad) de 0.5, 1, 2 y 4 kHz. Se lograron identificar restos auditivos aprovechables en todos los pacientes. Con la técnica multifrecuencia se estimaron curvas audiométricas completas para las frecuencias exploradas, incluso en ausencia de respuestas transitorias. La menor diferencia entre los umbrales auditivos estimados con ambos tipos de PEA se obtuvo para el tono de 4000 Hz, y la mayor diferencia para el tono de 500 Hz. Se demuestra que los PEA constituyen una técnica útil en la exploración audiológica objetiva de los pacientes sordociegos. Los PEA de estado estable multifrecuencia presentan cierta ventaja potencial sobre las respuestas evocadas transitorias en la caracterización de la audición residual en pacientes con perdidas auditivas severas o profundas (AU)

Difícil equilibrio / A difficult balance

No disponible

Jugular vein and carotid artery blood flow in fetuses with increased nuchal translucency at 10-14 weeks' gestation.

OBJECTIVE: The aim of our study was to obtain measurements of the jugular vein and carotid artery pulsatility index (PI) at 10-14 weeks' gestation in chromosomally normal and abnormal fetuses with or without increased nuchal translucency (NT), in order to explore whether a relationship exists between increased NT and overperfusion of the head. METHODS: This was a prospective study involving 179 pregnant women at high risk for chromosomal anomalies or structural malformations who were referred for chorionic villus sampling or first-trimester ultrasound examination at 10-14 weeks' gestation, respectively. Color and pulsed Doppler ultrasound were used to obtain jugular vein and carotid artery blood flow velocity waveforms at the level of the mid-neck. All Doppler measurements were obtained by a single investigator. The PIs of the jugular vein and carotid artery were correlated with NT measurement and fetal karyotype. RESULTS: Doppler measurements of the jugular vein and carotid artery were successfully obtained in 90.5% of the fetuses. The fetal karyotype was abnormal in 13 cases, including three trisomies 21 and two trisomies 18, and normal in 149 cases. In the group with normal karyotype the NT was above the 95th percentile in 22 cases (15%). No correlation between the jugular vein or the carotid artery PI and the thickness of the NT was found. There were no significant differences when comparing the values of the jugular vein and carotid artery PI between the group with normal NT and the group with increased NT, or between the group with a normal karyotype and an abnormal karyotype. CONCLUSION: Our results suggest that NT is not related to blood flow impedance in either the carotid artery or the jugular vein. Overperfusion and venous congestion of the head do not appear to be a causative pathophysiological mechanism involved in increased NT.

Marcadores bioquímicos de cromosomopatía durante el embarazo / Biochemical marked of chromosomopathy during pregnancy

La edad materna como único criterio se utilizó para seleccionar las gestaciones de alto riesgo de aneuploidía en los inicios de la amniocentesis para diagnóstico prenatal. La introducción del cribado bioquímico de segundo trimestre (alfafetoproteína + hCG) permitió en la década de 1990 duplicar la detección prenatal del síndrome de Down del 30 al 65 por ciento, manteniendo la misma tasa de falsos positivos, según han mostrado los amplios estudios prospectivos poblacionales. Aumentar hasta el 90 por ciento los diagnósticos parece estar a nuestro alcance si se combina la translucencia nucal con los marcadores bioquímicos de primer trimestre (PAPP-A+ hCG) (AU)