Direct temporal characterization of sub-3-fs deep UV pulses generated by resonant dispersive wave emission.

We report on the complete temporal characterization of ultrashort pulses, generated by resonant dispersive wave emission in gas-filled hollow-capillary fibers, with energy in the microjoule range and continuously tunable from the deep-ultraviolet to the ultraviolet. Temporal characterization of such ultrabroad pulses, particularly challenging in this spectral region, was performed using an all-in-vacuum setup for self-diffraction frequency resolved optical gating (SD-FROG). Sub-3-fs pulses were measured, tunable from 250 nm to 350 nm, with a minimum pulse duration of 2.4 ± 0.1 fs.

A cross-platform metabolomics workflow for volume-restricted tissue samples: application to an animal model for polycystic kidney disease.

Metabolic profiling provides an unbiased view of the physiological status of an organism as a "function" of the metabolic composition of a measured sample. Here, we propose a simple LC-MS based workflow for metabolic profiling of volume-restricted samples, namely individual 20 µm-thick histological sections of a mouse kidney. The main idea of this workflow is to re-use the material after an RPLC-MS run, namely using the volume remaining in the vial after injection, and then introducing a phase changing step to enable HILIC-MS analysis. To test the applicability of the workflow and its ability to extract valuable biological information, we applied it to an animal model of polycystic kidney disease (PKD).

Maternal education, dental visits and age of pacifier withdrawal: pediatric dentist role in malocclusion prevention.

OBJECTIVE: Although discouraged, pacifier usage is widespread and often practiced beyond two years of age. The current study explored the effects of maternal education and dental visits on the age of pacifier withdrawal. STUDY DESIGN: The dental histories of 213 children (53.1% male) attending a primary school in Madrid were obtained along with maternal education level and age at pacifier withdrawal. Data were analyzed by using independent samples t-test, one-way ANOVA two-way ANOVA and a complementary non-parametric approach was also used. RESULTS: There was a significant effect of maternal education on the age of pacifier withdrawal; the higher the maternal education, the younger the age of withdrawal. The frequency of dental visits influenced the relationship between maternal education and the age of pacifier withdrawal. Dental visits considerably shortened pacifier use among children with low- and medium-educated mothers. CONCLUSIONS: Pediatric dentists play a critical role in the correction of unhealthy oral habits such as prolonged pacifier use. The educational component of pediatric dentistry could reverse the lack of knowledge or misinformation among high-risk groups (e.g. low maternal education). As a consequence, we recommend that children start dental visits at an early age and maintain visits with a high frequency.

Determination and characterization of glycerophospholipids in olive fruit and oil by nonaqueous capillary electrophoresis with electrospray-mass spectrometric detection.

A nonaqueous capillary electrophoresis method with electrospray-mass spectrometric detection was developed to study the glycerophospholipid fraction in olive fruit and olive oil samples. In olive fruits, where the information available about the phospholipid fraction was very scarce, results obtained in this work allowed us to complete and improve this knowledge. The glycerophospholipid fraction of the olive fruit samples analyzed was composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), lysophosphatidylethanolamine (lyso-PE), phosphatidylinositol (PI), phosphatidic acid (PA), lysophosphatidic acid (lyso-PA), and phosphatidylglycerol (PG). Differences in the relative abundance of the glycerophospholipid classes determined were observed as a function of the botanical and geographical origin of the olive fruits analyzed. Interestingly, the olive stone and pulp analyzed also showed different glycerophospholipid compositions. For olive oil, five glycerophospholipids (lyso-PA, PC, PE, lyso-PE, and PG) were detected. Finally, identification of the main molecular species in the different glycerophospholipid classes for the olive fruit samples analyzed was accomplished by tandem mass spectrometric experiments and information from the literature.

Rapid separation of tetracycline derivatives and their main degradation products by capillary zone electrophoresis.

A mixture of five tetracycline (TC) derivatives: minocycline (MC), demeclocycline (DMCTC), doxycycline (DC), and sancycline (SC), as well as each TC derivative from its main degradation product were separated by capillary zone electrophoresis (CZE). The influence of the pH and the concentration and nature of the background electrolyte (BGE) on the separations was investigated. Ethylenediaminetetraacetic acid (EDTA; 1 mM) was used as additive in a 25 mM phosphate buffer (pH 2.3) because this BGE enabled the rapid separation of the TC derivatives and of each TC derivative from its respective degradation product in less than 6 min. After optimization of the separation conditions, the analytical characteristics of the method were investigated. The parameters involved were linearity, precision (repeatability and reproducibility), and limits of detection (LODs). LODs obtained for the five TC derivatives studied were about 3 microg/mL. Finally, the CZE method developed was applied to study the stability of TC derivatives and to analyze the TC derivative content in three different pharmaceutical preparations.

Application of capillary zone electrophoresis with off-line solid-phase extraction to in vitro metabolism studies of antifungals.

A simple and robust solid-phase extraction (SPE) procedure for the cleanup and sample preconcentration of antifungals (ketoconazole, clotrimazole, itraconazole, fluconazole, and voriconazole) and their metabolites after incubation with human liver microsomes, as well as a simplified capillary zone electrophoresis (CZE) method for their rapid analysis, have been developed to determine the stability of these compounds in in vitro samples. Three different sample pretreatment procedures using SPE with reversed-phase sorbents (100 mg C8, 100 mg C18, and 30 mg Oasis-HLB) were studied. The highest and most reproducible recoveries were obtained using a 30 mg Oasis-HLB sorbent and methanol containing 2% acetic acid as eluent. Enrichment by a factor of about four times was achieved by reconstituting the final SPE eluates to a small volume. For the CZE separation, good separations without interfering peaks due to the in vitro matrix were obtained with a simple running electrolyte using a fused-silica capillary. The best separation for all components originated by each tested drug after incubation with human liver microsomes (unmetabolized parent drug and its metabolites) was obtained using a 0.05 M phosphate running buffer (pH 2.2) without additives. The effect of the injection volume was also investigated in order to obtain the best sensitivity. Performance levels in terms of precision, linearity, limits of detection, and robustness were determined.

Optimization of the separation of a group of antifungals by capillary zone electrophoresis.

Two simple, rapid, and efficient methods for the analysis of seven antifungal compounds have been developed by capillary zone electrophoresis. Resolutions higher than 1.5 were obtained using 0.025 M phosphate buffer (pH 2.30) (analysis time close to 9 min) or 0.2 M formic acid (pH 2.15) (analysis time close to 6 min), with an applied voltage of 20 kV and a temperature of 30 degrees C. The highest sensitivity and selectivity can be obtained using phosphate buffer but the shortest analysis times are achieved in the formic system. The analytical characteristics of the optimized methods were investigated. The reproducibility obtained for migration times (RSD(n = 10) < or = 1.0%) and peak areas (RSD(n = 10) < or = 4.3%) was acceptable, but better reproducibilities were obtained when verapamil was used as internal standard (RSD(n = 10) < 0.4% for relative migration times and RSD(n = 10) < or = 2.2% for peak area ratios). The lowest limit of detection was obtained for clotrimazole (0.12 microg/ml) and the highest for fluconazole and voriconazole (0.90 microg/ml). The lowest and the highest limits of quantitation were, respectively, 0.40 microg/ml for clotrimazole and 3.00 microg/ml for fluconazole and voriconazole.

Rapid enantiomeric separation of polychlorinated biphenyls by electrokinetic chromatography using mixtures of neutral and charged cyclodextrin derivatives.

Electrokinetic chromatography with cyclodextrin derivatives (CD-EKC) was used to achieve the rapid enantiomeric separation of chiral polychlorinated biphenyls (PCBs). Thirteen of the 19 chiral PCBs stable at room temperature were individually separated into their two enantiomers by using 2-morpholinoethanesulfonic acid (MES) buffer (pH 6.5) containing carboxymethylated gamma-cyclodextrin (CM-gamma-CD) as pseudostationary phase mixed with beta-cyclodextrin (beta-CD) or permethylated beta-cyclodextrin (PM-beta-CD). Urea was also added to increase the solubility of PCBs and cyclodextrins in the aqueous separation buffer. Several experimental parameters such as the nature, concentration, and pH of the buffer, nature and concentration of the cyclodextrin derivatives used, and the addition of different additives were studied in order to improve the enantiomeric separation. In addition, the effect of some instrumental parameters such as separation temperature and applied voltage was also investigated. PCBs were enantiomerically separated in less than 12 min by using a 50 mM MES buffer (pH 6.5) containing 20 mM CM-gamma-CD, 10 mM beta-CD or 20 mM PM-beta-CD, and 2 M urea at a temperature of 45 degrees C and an applied voltage of 20 kV.

Listeriosis: una infección poco frecuente en pacientes con VIH / Listeriosis: an infrequent infection in patients with HIV

Aunque la resistencia a la infección por Listeria monocytogenes requiere que la inmunidad celular este indemne, la listeriosis es una enfermedad poco frecuente en los pacientes VIH+ y existen únicamente alrededor de unos 50 casos publicados. Se presentan los dos únicos enfermos VIH+ con infección por L. monocytogenes atendidos en nuestro hospital desde el inicio de la epidemia del sida en 1981. Caso 1: Varón VIH+ con 364 linfocitos CD4+ por mm3 que ingresó por cefalea occipital y fiebre. La tomografía axial computarizada cerebral fue normal y en el cultivo del líquido cefalorraquídeo creció L. monocytogenes. Se trató favorablemente con ampicilina y tobramicina. Caso 2: Varón de 47 años VIH+ con 44 linfocitos CD4+/ mm3 y cirrosis hepática por VHC que ingresó por fiebre elevada y distensión abdominal. Realizaba profilaxis para PCP con pentamidina IV. Con el diagnóstico de peritonitis bacteriana espontánea se extrajeron 3 hemocultivos y se inició tratamiento con ceftriaxona. Desarrolló encefalopatía hepática y falleció a las 72 h del ingreso. Postmortem se recibió crecimiento de L. monocytogenes. La listeriosis es una enfermedad poco frecuente en los enfermos VIH+, que esporádicamente produce cuadros de difícil diagnóstico, sobre todo en los enfermos que no realizan profilaxis para PCP con cotrimoxazol (AU)

Combined use of supercritical fluid extraction, micellar electrokinetic chromatography, and reverse phase high performance liquid chromatography for the analysis of antioxidants from rosemary (Rosmarinus officinalis L.).

Antioxidants from rosemary were determined by the combined use of supercritical fluid extraction (SFE) prior to reverse-phase high-performance liquid chromatography (RP-HPLC) or micellar electrokinetic chromatography (MEKC). The separation of antioxidants found in the SFE fractions was achieved by using a new MEKC method and a published HPLC procedure, both with diode array detection. The characterization of the different antioxidants was further done by HPLC-mass spectrometry. Advantages and drawbacks of HPLC and MEKC for analyzing the antioxidants found in the different extracts are discussed. From the results it is concluded that HPLC renders higher peak area and is better in its reproducibility than MEKC; both techniques provide similar analysis time reproducibility. The main advantage of MEKC is its much higher separation speed, which is demonstrated to be useful for the quick adjustment of SFE conditions, allowing rosemary fractions of higher antioxidative power to be obtained quickly. Moreover, the possibilities of this approach for following the degradation of antioxidants are discussed.

Influence of mobile phase composition on electroosmotic flow velocity, solute retention and column efficiency in open-tubular reversed-phase capillary electrochromatography.

The effects of some experimental parameters, such as the volume fraction and type of organic modifier in the mobile phase, and the concentration, type and pH of the buffer on the electroosmotic flow velocity, the retention behavior of test solutes, and the column efficiency have been investigated in capillary electrochromatography (CEC) using an open-tubular column of 9.60 microm I.D. with a porous silica layer chemically modified with C18 as stationary phase. The retention of a group of polycyclic aromatic hydrocarbons (PAHs) used as a test mixture varied significantly by changing the organic modifier content in the hydroorganic mobile phase according to the reversed-phase-like selectivity of the stationary phase. In addition, an increase in the percentage of organic modifier resulted in a slight increase in the linear velocity of the EOF. On the other hand, when the phosphate buffer concentration was increased over the range 1-50 mM, the electroosmotic mobility fell dramatically, the retention of the solutes decreased steadily, and the plate height showed a significant increase. The results obtained with phosphate, trishydroxymethylaminomethane or 2-morpholinoethanesulfonic acid as buffers were similar when pH remained constant. Optimization in CEC was essential to achieve further enhancement of separation performance, because the analysis time and separation resolution are essentially affected when varying operating parameters. Separations of seven PAHs with more than 100000 plates are presented within 4 min analysis time.

[Listeriosis: an infrequent infection in patients with HIV]. / Listeriosis: una infección poco frecuente en pacientes con VIH.

Although resistance to Listeria monocytogenes infection requires intact T-cell mediated immunity, listeriosis is an infrequent problem in patients with HIV infection and only about 50 patients have been reported to date. Only two patients with HIV and L. monocytogenes have been attended in our hospital since the beginning of aids epidemic in 1981. Case 1: a man with HIV and 364 CD4+ cells/mm3 presented fever and occipital headache. The cerebral scan was normal and L. monocytogenes grew in licuor culture. He was outcome after treatment with ampicillin and tobramycin. Case 2: a 47 years old man with HIV, 44 CD4+ cells/mm3 and hepatic virus C cirrhosis was admitted to the hospital because fever and abdominal distension. He was on menstrual pentamidine prophylaxis for Pneumocystis carinii pneumonia (PCP). Bacterial peritonitis was diagnosed and the patient begun treatment with ceftriaxone. The patient dead 72 hours later with hepatic encepholopathy. Postmortem L. monocytogenes grew. Listeriosis is an infrequent disease in patients with HIV that causes difficult diagnostic problems, principally in patients without prophylaxis with cotrimoxazole for PCP.

[Left-sided endocarditis in patients with HIV infection]. / Endocarditis de válvulas izquierdas en pacientes con infección por el VIH.

BACKGROUND: Left-sided endocarditis in HIV-infected patients has an special clinical, epidemiological and microbiological characteristics and its relationship with drug addicts subjects is unknown. PATIENTS AND METHODS: Since 1986 up to 1996 we have been diagnosed 214 episodes of infective endocarditis in 190 HIV-infected patients. In 34 cases (15%) there was left-sided endocarditis. These patients are described. RESULTS: Mean age was 30 years and 28 were male (82%). Thirty patients had been intravenous drug addicts (IVDA) but only 18 were active-IVDA. In three cases the endocarditis was nosocomial. Mean CD4+ lymphocyte count was 176 per mm3 and 59% were AIDS-patients. Tuberculosis was the most frequent opportunistic infection (14 cases). The presentation was subacute in 70% and the most important symptom was fever. Only 3 (9%) had septic emboli in chest X-ray. The affected valve was mitral in 31 patients (91%). The blood culture was negative in 21 episodes (62%) and only in 6, Staphylococcus aureus was isolated. The mortality was 18% and 68% were outcome without any problem. CONCLUSIONS: Left-sided endocarditis in patients with HIV infection is a very serious problem. It seems to affect to patients with severe immunosuppression and the culture blood may be negative. Its diagnosis is difficult and the mortality is elevated.

Endocarditis de válvulas izquierdas en pacientes con infecciónpor el VIH / Left-sided endocarditis in HIV infected patients

Fundamento: La endocarditis de localización izquierda en los pacientes VIH+ tiene unas especiales caracteristicas clinicas, epidemiológicas y microbiológicas y es desconocida su relación con la drogadicción. Pacientes y métodos: Entre 1986 y 1996 se diagnosticaron 214 episodios de endocarditis infecciosa en 190 pacientes VIH+. En 34 casos (15%) existió endocarditis de válvulas izquierdas (EVI). Se describen sus hallazgos clínicos, inmunológicos, epidemiológicos y evolutivos. Resultados: La edad media fue 30 años y 28 (82%) eran varones. 30 habían sido drogadictos (88%) y 18 continuaban con consumo activo. En 3 casos, la EVI fue nosocomial. La media de linfocitos CD4+ fue de 176 por mm3 y el 59 porciento cumplían criterios de sida. La infección oportunista diagnosticada con mayor frecuencia fue la tuberculosis (14 casos). La evolución fue subaguda en el 70 porciento y la fiebre la manifestación clínica fundamental. Sólo 3 (9%) presentaron émbolos sépticos en la radiografía de tórax. La localización más frecuente fue la mitral (31 pacientes, 91 porciento). En 21 episodios (62 %) los hemocultivos fueron negativos y sólo en 6 (18%) el responsable fue el Staphylococcus aureus. La mortalidad fue del 18% y el 68 porciento curaron sin secuelas. Conclusiones: La EVI en los pacientes con infección por VIH aparece de forma subaguda, en los gravemente inmunodeprimidos y con frecuencia los hemocultivos son negativos. Tiene una elevada mortalidad y su diagnóstico es difícil (AU)

Chiral separation of polychlorinated biphenyls by micellar electrokinetic chromatography with sodium cholate.

Micellar electrokinetic chromatography (MEKC) with one kind of bile salt (sodium cholate) was used to separate three chiral polychlorinated biphenyls (PCBs; 84, 95, and 176), each one in its two enantiomers. Sodium cholate was used as chiral surfactant in a 2-(N-cyclohexylamino) ethanesulfonic acid (CHES) buffer under alkaline (pH 10) conditions containing urea (2 M). The influence of bile salt concentration on the efficiency and the resolution between the two enantiomers of PCBs 84 and 95 was established. The chiral separation of three PCBs was successfully achieved in less than 30 min (approximately 23 min for PCB 176 and approximately 29 min for PCBs 84 and 95).

[Polymicrobial endocarditis: a clinical and evolutive study of 12 cases diagnosed during a 10-year period]. / Endocarditis polimicrobiana: estudio clínico y evolutivo de doce casos diagnosticados durante un período de diez años.

Polymicrobial endocarditis (PE) is uncommon, whether in series of cases of polymicrobial bacteriemia or of endocarditis. Among the 201 cases of infective endocarditis seen between 1986 and 1995 by an infectious diseases service, 12 patients had PE (6%). Nine were males, mean age was 28 years and ten were active intravenous drug users. All of them were HIV (+) and 50% had AIDS. Eleven subjects had infection of the tricuspid valve and 58% developed septic pulmonary emboli. The most common organism encountered was Staphylococcus aureus in 8 patients followed by Streptococcus viridans and S. pneumoniae in three. The most common combinations of organisms were S. aureus and S. pneumoniae in 3 cases and S. aureus and Pseudomonas aeruginosa in two. Two patients died, one with Xantomona maltophilia and another with Candida albicans. The symptoms of PE were usually indistinguishable from endocarditis caused by a single organism and the prognosis depended on the species rather than the number of organisms isolated.