Preparation and evaluation of unitary doses of propafenone used in children with supraventricular tachycardia: a pilot study.

PURPOSE: The aim was to prepare and evaluate unitary doses of propafenone (UDP) used in children with supraventricular tachycardia. METHODS: UDP were prepared from four brands of tablets at doses of propafenone, 11, 25 and 90 mg, used in the Cardiology Service of this Institute. The stability of doses was determined at 20±5°C and 40°C for up to day 30. Besides, a weight variation test was performed. Plasma levels of propafenone were determined at steady state in 3 children diagnosed with supraventricular tachycardia under treatment with UDP. Concentrations of drug in blood were measured using a high pressure liquid chromatography method, previously validated. RESULTS: The stability of UDP, showed no significant statistical differences (p > 0.05) between doses or brands up to day 30, at both temperatures. The coefficient of variation from the weight variation was less than 6%. The plasma levels of propafenone at steady state were: patient 1, 31.57 ng/ml; patient 2, 226.46 ng/ml; and patient 3, 221.29 ng/ml. CONCLUSIONS: The actual administered dose for the patients could vary up to 6%, and doses prepared from different brands of tablets remain stables for up to day 30 at both temperatures. UDP is a temporal, safe and alternative option when pediatrics formulation of this drug is lacking.

Mutations in NPHS2 (podocin) in Mexican children with nephrotic syndrome who respond to standard steroid treatment.

Human nephrotic syndrome has been related to mutations in glomerular proteins. Mutations in the NPHS2 gene that encodes podocin have been described as responsible for steroid-resistant nephrotic syndrome. It has been advised to test for NPHS2 mutations in parallel or before giving steroid treatment in nephrotic syndrome patients in order to avoid unnecessary therapy. We identified NPHS2 mutations in Mexican children with nephrotic syndrome. The study included 13 children with nephrotic syndrome and 2 healthy control individuals; 8 patients were steroid-resistant and 5 were steroid-sensitive. We analyzed the 3rd exon of NPHS2 by DNA sequencing. Podocin heterozygous missense mutations L139R and L142P were found; the former was found in both steroid-sensitive and steroid-resistant children, while the latter was found in a steroid-resistant child. We conclude that NPHS2 mutations should be investigated to help decide the course of treatment in nephrotic syndrome patients.

[Transcranial Doppler ultrasound, bispectral index, and electroencephalographic monitoring of entropy during sevoflurane anesthesia in children]. / Doppler transcraneal, BIS y entropía como medición indirecta del flujo cerebral durante la anestesia inhalatoria en pacientes pediátricos.

BACKGROUND AND OBJECTIVE: Transcranial Doppler ultrasound is a noninvasive technique for monitoring the velocity of blood flow in the main intracranial arteries, particularly those in the circle of Willis. Our aim was to assess whether changes in cerebral arterial blood flow in pediatric patients under sevoflurane anesthesia demonstrated by pulsed Doppler ultrasound correlate with changes in the bispectral (BIS) index and electroencephalographic state and response entropy (ES and ER, respectively). MATERIAL AND METHODS: Prospective, blinded observational study of 36 pediatric patients (age range, 5 to 11 years; ASA physical status classification, 1-2) under sevoflurane anesthesia for minor surgical procedures. Anesthesia was induced with sevoflurane and maintained with 2.5% sevoflurane in an inspired oxygen fraction of 50% in air. A continuous perfusion of remifentanil was provided for analgesia. In all patients we monitored hemodynamic and respiratory patterns, gases, temperature, and hypnosis (BIS, ES and ER) as well as cerebral blood flow estimated by pulsed Doppler ultrasound in the middle cerebral artery. The resistance index, pulsatility index, mean velocity, and estimated baseline cerebral blood flow were calculated from the Doppler sonogram. Correlations (Pearson's r) were calculated between BIS, ES, ER, the pulsatility index, resistance index, mean flow velocity, estimated cerebral blood flow, fraction of end-tidal carbon dioxide, and temperature. A regression model was constructed. RESULTS: Induction caused a pattern of high velocity (elevated mean velocity and normal or reduced pulsatility index) until the lowest BIS and ES values of 31 and 29, respectively, were reached. During maintenance, the Doppler sonogram pattern was slower (normalization of the pulsatility index, the resistance index, and mean velocity). Changes in flow and absolute entropy and BIS values were statistically correlated (Pearson's r values > or = 0.91); there was 95.6% agreement between Doppler values and BIS and agreement between BIS and ES values of 35 to 45. On awakening, flow velocities approached baseline values when BIS and ES rose to between 90 and 98. The estimated cerebral blood flow underwent fluctuations coinciding with an approximately concomitant increase or decrease in BIS (r > 0.95); the BIS response occurred with a slight delay of no more than a minute. The entropy measurements did not reflect the fluctuations. CONCLUSIONS: We show Doppler ultrasound patterns during anesthetic induction with sevoflurane. Systems for monitoring hypnosis could be considered indirect measurements of cerebral blood flow; BIS measurements are more sensitive to change. Transcranial Doppler ultrasound facilitates the observation of changes in blood flow that occur at different levels of hypnosis during anesthesia.

Methods of estimation of pleural effusion by ecography. / Métodos de estimación de derrame pleural por ecografía.

Pleural effusion is a frequent pathology in intensive care units. The diagnosis has improved after the introduction of pulmonary ultrasound, an accessible method at the bedside, which allows not only the diagnosis but also the treatment of this entity. The aim of our study is to determine the accuracy of published mathematical equations to calculate the volume of pleural effusion from ultrasound measurements. After doing a systematic review, seven articles were selected that each proposed a mathematical equation. In all of them the results were statistically significant. However, there is no ideal formula among those studied.

Imaging performance of a dedicated radiation transparent RF coil on a 1.0 Tesla inline MRI-linac.

This work describes the first imaging studies on a 1.0 Tesla inline MRI-Linac using a dedicated transmit/receive RF body coil that has been designed to be completely radio transparent and provide optimum imaging performance over a large patient opening. A series of experiments was performed on the MRI-Linac to investigate the performance and imaging characteristics of a new dedicated volumetric RF coil: (1) numerical electromagnetic simulations were used to measure transmit efficiency in two patient positions; (2) image quality metrics of signal-to-noise ratio (SNR), ghosting and uniformity were assessed in a large diameter phantom with no radiation beam; (3) radiation induced effects were investigated in both the raw data (k-space) and image sequences acquired with simultaneous irradiation; (4) radiation dose was measured with and without image acquisition; (5) RF heating was studied using an MR-compatible fluoroptic thermometer and; (6) the in vivo image quality and versatility of the coil was demonstrated in normal healthy subjects for both supine and standing positions. Daily phantom measurements demonstrated excellent imaging performance with stable SNR over a period of 3 months (42.6 ± 0.9). Simultaneous irradiation produced no statistical change in image quality (p > 0.74) and no interference in raw data for a 20 × 20 cm radiation field. The coil was found to be efficient over large volumes and negligible RF heating was observed. Volunteer scans acquired in both supine and standing positions provided artefact free images with good anatomical visualisation. The first completely radio transparent RF coil for use on a 1.0 Tesla MRI-Linac has been described. There is no impact on either the imaging or dosimetry performance with a simultaneous radiation beam. The open design enables imaging and radiotherapy guidance in a variety of positons.

Gradient induced artifacts in simultaneous EEG-fMRI: Effect of synchronization on spiral and EPI k-space trajectories.

The nature of the gradient induced electroencephalography (EEG) artifact is analyzed and compared for two functional magnetic resonance imaging (fMRI) pulse sequences with different k-space trajectories: echo planar imaging (EPI) and spiral. Furthermore, the performance of the average artifact subtraction algorithm (AAS) to remove the gradient artifact for both sequences is evaluated. The results show that the EEG gradient artifact for spiral sequences is one order of magnitude higher than for EPI sequences due to the chirping spectrum of the spiral sequence and the dB/dt of its crusher gradients. However, in the presence of accurate synchronization, the use of AAS yields the same artifact suppression efficiency for both pulse sequences below 80Hz. The quality of EEG signal after AAS is demonstrated for phantom and human data. EEG spectrogram and visual evoked potential (VEP) are compared outside the scanner and use both EPI and spiral pulse sequences. MR related artifact residues affect the spectra over 40Hz (less than 0.2 µV up to 120Hz) and modify the amplitude of P1, N2 and P300 in the VEP. These modifications in the EEG signal have to be taken into account when interpreting EEG data acquired in simultaneous EEG-fMRI experiments.

A reliable method to quantify sildenafil and its metabolite N-demethylsildenafil by HPLC in plasma of children.

The aim of this study was to develop a simple method for quantifying plasma levels of sildenafil and its metabolite by liquid chromatography with a C18 reverse-phase column and UV detection. For both compounds, linearity was assessed in the range from 10 and 1 000 ng · ml-1 and had correlation coefficients of r=0.995 and r=0.997 for sildenafil and its metabolite, respectively. The inter- and intra-day coefficients of variation was<5.3%. The limits of detection and quantification were 1 and 10 ng · ml-1. Drug levels were determined satisfactorily in two patients. A simple and reliable method was developed for use in children with Pulmonary Arterial Hypertension under treatment with sildenafil.

Epidemiology of depression in Latin America.

The focus of this review will center on the Epidemiology of affective disorders in Latin America. The prevalence seems to be very similar in the general population. Argentina reports 12%, Chile 15.3%, Dominican Republic 9.8% and Peru 11%. In non-psychiatric outpatient program, the prevalence is 53% in Costa Rica, 40% in Cuba, 39% in Dominican Republic and 19% in Mexico. Women outnumber men in all samples. There are reports of higher prevalence in special groups: Mariategui found 25% in Lima and Vega 26% in Mexico. It is suggested that the Latin American Socio-Economic situation may be an important determinant of these high rates.

Insuficiencia renal aguda como manifestacion inicial de leucemia. Informe de 1 caso. / Acute renal failure as initial manifestation of leukemia.Report of a case

Se informa el caso de un adolescente de 14 anos de edad que ingreso al Hospital del Nino del Noroeste DIF, por presentar cuadro clinico y bioquimico de insuficiencia renal aguda, estableciendose el diagnostico de leucemia un dia antes de su fallecimiento. El estudio postmortem revelo crecimiento renal bilateral por infiltracion de celulas leucemicas. Se describe el caso en sus aspectos clinicos; de laboratorio y anatomopatologicos mas sobresalientes ademas se enfatiza la necesidad de hacer diagnostico diferencial con leucemia ante un paciente con insuficiencia renal aguda y pancitopenia periferica

Enfermedad de Gilbert. Presentacion de dos casos. / Gilbert's disease.Report of 2 cases

Se presentan dos casos de hiperbilirrubinemia familiar no conjugada (enfermedad de Gilbert), detectada en dos hermanos, uno del sexo masculino de 12 anos de edad, con manifestacion clinica (ictericia) apreciada desde la primera semana de vida, con remision y reaparicion a los 5 anos, cursando posteriormente asignologico y asintomatico hasta su admision al hospital; el otro, una hermana de 15 anos de edad cuyos sintomas se iniciaron a los 12 anos. Se practicaron diversos examenes de laboratorio tendientes a descartar padecimientos tales como anemias hemoliticas, hepatitis persistente, enfermedad de Crigler-Najjar, Dubin-Johnson y sindrome de Rotor.Se practico biopsia hepatica y estudio de medula osea resultado normales. El unico parametro de laboratorio alterado fue elevacion de bilirrubina no conjugada de manera moderada hasta 6 mg/dl; por exclusion se diagnostico enfermedad de Gilbert, instalandose prueba terapeutica con excelentes resultados