New magnetic chelating sorbent for chromium speciation by magnetic solid phase extraction on-line with inductively coupled plasma optical emission spectrometry.

A novel sorbent material employing magnetic nanoparticles (MNPs) coupled to graphene oxide (GO) functionalized with 4-aminobenzenesulfonic acid (M@GO-ABS) has been synthesized and applied to develop an inexpensive and automatic method for Cr(III) and Cr(VI) speciation in environmental samples; the developed method combines inductively coupled plasma optical emission spectrometry (ICP-OES) with on-line magnetic solid phase extraction (MSPE). Two magnetic-knotted reactors containing M@GO-ABS were installed in the eight-port injection valve of a flow injection (FI) manifold. Two different eluents were used, one for Cr(VI) (the most toxic chromium species) and one for total Cr concentration. Cr(III) concentration was calculated by the difference between Cr(VI) concentration and total Cr concentration. The optimized method presented detection limits (LOD, peak height) of 0.1 µg L-1 for chromium (VI) and 0.08 µg L-1 for total chromium, and enrichment factors of 15 and 23, respectively. Certified reference materials (TMDA 54.5 fortified lake water and SPS-SW2 surface water) and spiked aqueous samples were used to validate the developed method. The developed method was fruitfully applied to chromium speciation in environmental water samples such as seawater, well water and tap water collected in Málaga (Spain). The obtained values were in good agreement with the certified values, and the recoveries were found in the range of 91-108% for the spiked samples.

Semiautomatic method for the ultra-trace arsenic speciation in environmental and biological samples via magnetic solid phase extraction prior to HPLC-ICP-MS determination.

A novel magnetic functionalized material based on graphene oxide and magnetic nanoparticles (MGO) was used to develop a magnetic solid phase extraction method (MSPE) to enrich both, inorganic and organic arsenic species in environmental waters and biological samples. An automatic flow injection (FI) system was used to preconcentrate the arsenic species simultaneously, while the ultra-trace separation and determination of arsenobetaine (AsBet), cacodylate, AsIII and AsV species were achieved by high performance liquid chromatography combined with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was introduced in the FI system where the MSPE was performed, then 1 mL of eluent was collected in a chromatographic vial, which was introduced in the autosampler of HPLC-ICP-MS. Therefore, preconcentration and separation/determination processes were automatic and conducted separately. To the best of our knowledge, this is the first method combining an automatic MSPE with HPLC-ICP-MS for arsenic speciation, using a magnetic nanomaterial based on MGO for automatic MSPE. Under the optimized conditions, the LODs for the arsenic species were 3.8 ng L-1 AsBet, 0.5 ng L-1 cacodylate, 1.1 ng L-1 AsIII and 0.2 ng L-1 AsV with RSDs <5%. The developed method was validated by analyzing Certified Reference Materials for total As concentration (fortified lake water TMDA 64.3 and seawater CASS-6 NRC) and also by recovery analysis of the arsenic species in urine, well-water and seawater samples collected in Málaga. The developed method has shown promise for routine monitoring of arsenic species in environmental waters and biological fluids.

Direct solid sampling for speciation of Zn2+ and ZnO nanoparticles in cosmetics by graphite furnace atomic absorption spectrometry.

The application of nanoparticles (NPs) in science and technology is a fast growing field. Therefore, reliable and straightforward analytical methods are required for their fast determination in different types of samples. This work investigates a method that enables the determination of ZnO NPs, discriminating them from ionic zinc in cosmetic samples. The method is based on direct solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry (SS-HR-CS-GFAAS), and has been applied to determination of ZnO NPs, Zn2+ and total Zn in eye shadow samples. In this work the deconvolution of the atomization peak and the calibration by standard additions have been done in order to discriminate and quantify ionic zinc and ZnO NPs. A Zn wavelength with low sensitivity was selected. The proper optimization of the graphite furnace temperature program, minimizing the mineralization of the sample matrix, enables different atomization profiles between the different chemical species of the analyte. Two multiple response surface designs have been used in order to optimize the adequate furnace program to achieve our aims. All the optimization experiments were performed using a sample of eye shadow. Further, a method for the determination of total Zn by direct solid sampling with calibration by aqueous standards, was also optimized. The optimized method was successfully applied to the determination of ionic Zn and ZnO NPs in different eye shadow samples, and has been validated by recovery assays, obtaining recovery percentages between 80 and 125%. Total Zn concentration in the solid samples was validated by the determination of total Zn by direct solid sampling and by the analysis of the same eye shadow samples digested in microwave oven.

Experience with Guillain-Barré syndrome in a neurological Intensive Care Unit. / Experiencia del síndrome de Guillain-Barré en una Unidad de Cuidados Intensivos neurológicos.

INTRODUCTION: Guillain-Barré syndrome, an acute polyradiculoneuropathy that presents with weakness and areflexia, is the most common cause of acute flaccid paralysis. In certain patients, respiratory failure is secondary to this disorder, eventually causing patients to require mechanical ventilation and experience additional complications due to diminished respiratory support and related mobility limitations. Prognoses for most of these cases are positive; treatment consists of basic support combined with plasmapheresis or administration of immunoglobulins. OBJECTIVE: This study sought to describe the socio-demographic, clinical, laboratory and neurophysiological characteristics of patients with Guillain-Barré syndrome who were hospitalised in the Intensive Care Unit of the Neurological Institute of Colombia between 2006 and 2012. METHODOLOGY: This study presents a case series. RESULTS: We surveyed 25 patients (32% female and 68% male) with Guillain-Barré syndrome and an average age of 54 years. Sixty per cent of these patients were admitted between days 3 and 7 after symptom onset; 64% had a history of respiratory infection and 20% had a history of intestinal infection. In addition, 84% of the patients presented with albuminocytological dissociation. We observed the following clinical subtypes of Guillain-Barré syndrome: inflammatory demyelinating polyneuropathy in 32%, acute motor-sensory axonal neuropathy in 28%, acute motor axonal neuropathy in 28%, and Miller Fisher syndrome in 12%. CONCLUSIONS: In this descriptive study of a group of critical care patients with GBS, results depended on patients' clinical severity at time of admission. Our findings are similar to results published in the international literature.

[Orbital approach for treatment of carotid-cavernous sinus fistula]. / Abordaje orbitario para el tratamiento de la fístula carótido-cavernosa.

CASE REPORT: A male patient with a left carotid-cavernous sinus fistula (CCSF) and two previous attempts of embolization via the femoral vein was treated with embolization through the superior ophthalmic vein (SOV). DISCUSSION: The main modality of treatment for CCSF is intervention radiology. This aims to occlude the fistula via an arterial route, through the cavernous sinus, or via a venous route, through the inferior petrosus sinus. However, the CCSF is also accessible through the SOV.

[Evidence-based ophthalmology: critical evaluation of the literature in relation to diagnostic tests]. / Oftalmología basada en pruebas: evaluación crítica de la literatura sobre pruebas diagnósticas.

PURPOSE: In general, articles on diagnostic tests have a very poor methodological quality. If we translate their conclusions to daily practice without a proper analysis it is easy to see a typical trend: physicians use new (and expensive) tests without increasing diagnostic capacity; they only increase the health budget. Evidence-based medicine (EBM) consists of using the best evidence in decision-making. It deals with selected and relevant information, supported by data obtained through the most rigorous scientific method: epidemiology and statistics. Critical evaluation of papers related to diagnostic tests is our aim. We provide with basic skills for evaluation and analysis of papers by means of simple topics on statistics, design of clinical assays and clinical epidemiology. METHODS: Review of the medical literature. RESULTS: To evaluate papers on diagnostic tests and to use a test correctly, it is necessary to know its diagnostic capacity, the level of certainty to start treatment, the probability of having the disease before using the test and the test capacity to change that probability. CONCLUSIONS: The maximum performance of a test is reached when it is used in a maximum uncertainty situation (disease probability 50%). Its highest usefulness is obtained when pre-test probability is maximal, after a careful review of the patient's history and a complete patient examination.

[Intraocular lens (IOL) power calculation after keratorefractive procedures]. / Cálculo del poder dióptrico de la lente intraocular (LIO) tras cirugía refractiva.

PURPOSE: To compare various methods of estimating corneal power for IOL calculation for cataract surgery after corneal refractive surgery. METHODS: Review of the medical literature and case reports. RESULTS: For more accurate IOL power calculations we need pre- (Kpre) and post-treatment keratometry records (Kpost) if using 3rd generation formulae, or Kpost records when using 4th generation formulae. CONCLUSIONS: Prior to performing a keratorefractive procedure it is advisable to have pre-treatment refraction and keratometry (K and method) registered. 3rd generation formulae with Aramberri's double-K correction, or 4th generation formulae are recommended.

Cálculo del poder dióptrico de la lente intraocular (LIO) tras cirugía refractiva / Intraocular lens (IOL) power calculation alter keratorefractive procedures

Objetivo: Comparar los distintos métodos de estimación del poder refractivo de la córnea para el cálculo la lente intra-ocular (LIO) para la cirugía de cataratas después de cirugía refractiva corneal.Método: Revisión de la literatura médica y de series de casos clínicos.Resultados: Para el cálculo más exacto de la LIO necesitamos la queratométría previa (Kpre) y posterior (Kpost) a la cirugía refractiva si utilizamos una fórmula de 3.ª generación o solamente la Kpost si optamos por una fórmula de 4.ª generación.Conclusiones: Previamente a la cirugía refractiva es conveniente registrar la refracción y queratometría (K y método). Se recomienda utilizar fórmulas de 3.ª generación con la corrección doble-k de Aramberri o fórmulas de 4.ª generación

Purpose: To compare various methods of estimating corneal power for IOL calculation for cataract surgery after corneal refractive surgery. Methods: Review of the medical literature and case reports. Results: For more accurate IOL power calculations we need pre- (Kpre) and post-treatment keratometry records (Kpost) if using 3rd generation formulae, or Kpost records when using 4th generation formulae. Conclusions: Prior to performing a keratorefractive procedure it is advisable to have pre-treatment refraction and keratometry (K and method) registered. 3rd generation formulae with Aramberri’s double-K correction, or 4th generation formulae are recommended

Nucleotide regulation of vasoactive intestinal peptide binding to bovine thyroid plasma membranes.

The specific binding of vasoactive intestinal peptide (VIP) to bovine thyroid plasma membranes is inhibited by guanine nucleotides. Guanosine 5'-triphosphate (GTP) and the non-hydrolyzable GTP analogs guanosine 5'-beta,gamma-imidotriphosphate (Gpp(NH)p) and guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S) inhibited markedly the binding of VIP to its receptors. This inhibition was higher with GTP than with Gpp(NH)p and GTP-gamma-S and was due to an increase of the rate of dissociation of peptide bound to membranes. Other nucleotides did not show any effect.

Effect of chronic intake of ethanol on the binding of vasoactive intestinal peptide to rat spleen lymphoid cells.

1. The effect of chronic intake of ethanol on the binding of vasoactive intestinal peptide (VIP) to rat spleen lymphoid cells was investigated. 2. The intake chronic of ethanol elicited an increase in specific VIP binding. 3. This increase was due to an increase in binding capacity of both the high and the low affinity binding sites. 4. There was a decrease in the affinities of both classes of VIP binding sites.