Analysis of neutral surfactants by non-aqueous medium capillary electrophoresis hyphenated to mass spectrometry (ion trap).

Non-derivatized Brij 58 oligomers were analyzed by using non-aqueous capillary electrophoresis (NACE) hyphenated to mass spectrometry (ion trap). The separation of this neutral polyethylene oxide surfactant was based on its complexation with ammonium cation in methanolic medium. Cationic complexes were formed within the capillary and migrated against the anodic electroosmotic flow. The latter was obtained by using a pre-treatment of the capillary with hexadimethrine bromide. By optimizing mass detection and the separation conditions separately, it was demonstrated that two different salts had to be used. Ammonium acetate was used in the sheath liquid to optimize detection sensitivity whereas ammonium iodide was used in the running electrolyte in order to obtain the more appropriate electroosmotic flow for the separation. Despite an aspiration effect due to the hyphenation with MS. that did not allow us to obtain a baseline resolution for the entire mixture, we were able to visualize and characterize more than 25 oligomers of Brij 58. As regards detection sensitivity, the limits of detection (LOD) were estimated at about 7.5 ng for the entire distribution of Brij 58 and 15 pg for C(16)E(5) or C(16)E(6) used as standards.

Analysis of neutral surfactants by non-aqueous capillary electrophoresis using an electroosmotic flow reversal.

The separation of KM 20, that is in fact a mixture of non-ionic surfactants, was carried out by non-aqueous capillary electrophoresis. This complex mixture resulting from the condensation of ethylene oxide with fatty alcohols does not have chromophoric moieties. So, we analysed it after derivatization by means of 3,5-dinitrobenzoyl chloride. The proposed approach is based both on the formation of complexes with alkaline or ammonium cations in methanol and on the utilisation of a positively charged capillary. From a comparative study on the capillary treatment procedure, we used hexadimethrine bromide as electroosmotic flow reverser in order to obtain both repeatable analyses and good resolutions of the largest KM 20 oligomers. Then, among the five cations used to form complexes with KM 20, we pointed out that ammonium cation led to the best resolutions. Moreover, we evidenced that the counter-ion of this cation had a great influence on resolution because it modified the magnitude of electroosmotic flow. Ion pair formation that is more or less strong between ammonium and its counter-ion was involved in this variation of electroosmotic flow. So, we calculated the association constants for various ammonium salts in methanol. Then, using ammonium chloride as background electrolyte, we optimised the concentration of this salt, in methanol, in order to reach the optimal separation of KM 20 oligomers. Thus, a baseline separation was obtained by using 6 x 10(-2) mol/L NH4Cl as running electrolyte. In these conditions, we separated, in about 30 min, more than 30 oligomers of KM 20. The distribution of these oligomers that was determined from the optimal separation, appeared consistent with that obtained from HPLC analyses. Indeed, we determined that the mean ethoxylation number was equal to 18 while its real value is equal to 20.

Electrophoretic separations of twelve phenothiazines and N-demethyl derivatives by using capillary zone electrophoresis and micellar electrokinetic chromatography with non ionic surfactant.

We focused our work on the separation of phenothiazines that are important drugs used for the treatment of psychic diseases. For a better understanding of the metabolism of these solutes, we wanted to separate not only a mixture of 12 phenothiazines but also a mixture containing phenothiazines and their N-demethyl metabolites by capillary electrophoresis. Separations in capillary zone electrophoresis were performed using 3 x 10(-2) mol/L H3PO4 (pH 2.5) but the obtained resolutions were not entirely satisfactory especially with regard to phenothiazine -N-demethyl derivative pairs. To improve the obtained results, we have performed separations by using micellar electrokinetic chromatography. In this approach, we used a running electrolyte containing 3 x 10(-2) mol/L H3PO4 electrolyte (pH 2.5) and octaethylene glycol monododecyl ether (C12E8) as neutral surfactant. By introducing 2 x 10(-3) mol/L C12E8 in the electrolyte, 11 out of 12 phenothiazines have been baseline separated. With respect to the separation of a mixture containing 3 phenothiazines and their 3 demethyl derivatives, we obtained an excellent separation by using a running electrolyte prepared with 7.5 x 10(-4) mol/L C12E8 and 3 x 10(-2) mol/L H3PO4.

Study of the acid hydrolysis of (3-methacryloxypropyl)trimethoxysilane by capillary electrophoresis-ion-trap mass spectrometry.

The sol-gel method is a widely used technique for the synthesis of various functional coating films. Alkoxysilanes such as (3-methacryloxypropyl)trimethoxysilane (MEMO) are largely used as precursors for inorganic-organic hybrid sol-gel materials. Indeed, these compounds can form complex network, through hydrolysis and condensation reactions. The latter have to be perfectly controlled to obtain the required properties. In such a context, we have studied the potentialities of capillary electrophoresis-ion-trap mass spectrometry (CE-MS) coupling to resolve both separation and characterization of the synthesized compounds as a function of the hydrolysis time. The study of acid hydrolysis of MEMO was carried out as an example. After optimization of the running electrolyte in capillary zone electrophoresis (CZE) with UV detection, we characterized the synthesized compounds in CE-MS by using positive detection mode. The obtained resolution in CZE-UV was not entirely satisfactory because of the very closed charge/mass ratio of formed solute but also because of the interaction between the solutes and the capillary walls. Nevertheless, several oligomers were characterized in CE-MS. The absence of detection with regard to oligomers that possess higher molecular masses than octamer is discussed in this work.

Utilization of fluorescein sodium salt for the indirect fluorimetric detection in micellar electrokinetic chromatography.

The potential of fluorescein sodium salt to generate a background signal in indirect fluorimetric detection in micellar electrokinetic chromatography (MEKC) has been studied by using a sample test containing various alcohols (methanol, ethanol, propan-1-ol, propan-2-ol, 2-methylpropan-1-ol, pentan-3-ol, 2-methylbutan-1-ol, 3-methylbutan-1-ol), acetaldehyde, acetone and ethyl acetate. In order to optimize sample test resolution and detection sensitivity, we have studied different parameters: sodium dodecyl sulfate concentration, electrolyte ionic strength, applied voltage as well as that of the addition of an organic cosolvent within the running electrolyte. Although the micellar pseudo-phase was not able to be saturated with the fluorophore in order to obtain the maximal detection sensitivity, the detection thresholds were satisfactory. By way of example, the detection threshold reached for 3-methylbutan-1-ol is 0.03% (v/v). The quantitative aspect was approached with ethanol titration in a commercial white wine. Finally the repeatability relating to, on the one hand, the effective electrophoretic mobilities and, on the other hand, the corrected areas has also been studied.

[Prick tests using RM steel lancets]. / Pruebas cutáneas por punción con lancetas de acero RM.

There exist several technics of application for allergy skin tests: intradermal in which the antigen is injected in the dermis: mean while in the other puncture method (PRICK), the antigen is applied on the skin and it is introduced with a device in the epidermis which there exist several technics of application. Realizing an analysis of different methods it's known that in the patients in which are indicated to realize direct skin test, we should practice first the puncture test, which are easy to apply with less or a minimum systemic and local reactions. To facilitate its application and reduce costs, we suggest the modified method, in a tray Multiwell with antigen, where are put sterilized reusable steel lancets previous sterilization to realize the punctures. We analyze different costs in materials that are used so they would be of easy acquisition.

Percutaneous revascularization of complex iliac artery stenoses and occlusions with use of Wallstents: three-year experience.

PURPOSE: To assess the outcome of percutaneous placement of Wallstents for treatment of hemodynamically significant diffuse stenoses (> 3 cm in length), chronic occlusions, failed angioplasty procedures, and flow-limiting dissection in the iliac arteries. MATERIALS AND METHODS: Lesions in 94 iliac limbs were treated in 66 patients. Indications for stent placement included claudication in 49 limbs and limb-threatening ischemia in 45. Forty-two limbs were treated for diffuse disease, 39 for chronic occlusion, nine for failed angioplasty, and four for flow-limiting dissection. RESULTS: Technical success was achieved in 86 of 94 limbs (91%), with major complications in 9% of patients. One death occurred within 30 days (not procedure-related). Ankle-brachial indexes improved from 0.51 +/- 0.24 to 0.76 +/- 0.22 (P < .001). Eighty-five percent demonstrated improvement under Rutherford criteria. Follow-up was obtained up to 38 months (mean, 14 months +/- 8). Cumulative primary patency rates were 78% at 1 year and 53% at 2 and 3 years (standard error 10%). Secondary patency rates were 86% at 1 year and 82% up to 32 months (standard error > 10% after 32 months). No significant decrease in mean ankle-brachial index was observed during follow up. No difference in primary patency was observed based on lesion type, symptom severity, lesion location, or runoff status. The limb salvage rate for patients with limb-threatening ischemia was 98% at a mean follow-up of 14 months +/- 7. CONCLUSIONS: Technical success and complication rates for percutaneous iliac artery revascularization with use of Wallstents are favorable, symptoms improved in the majority of patients, and excellent secondary patency can be achieved. With use of Wallstents, most patients with iliac artery insufficiency as a result of long-segment disease or chronic occlusions can be treated percutaneously.

[Hypersensitivity to airborne allergens common in the central region of Coahuila]. / Estudio de hipersensibilidad a aeroalergenos frecuentes en la región centro de Coahuila.

A retrospective review of 247 clinical files of patient that have responded to the office allergy and immunology since 1990 to 1993 in Monclova, Coah., for allergy illness. This study was to determine the frequency of Aeroalergens and foods sensitization in Monclova, Coahuila, mediated Allergy Test Skin (intradermo reactions, and Prick) and MAST immuno Systems (Multiple Allergy System Test). The patients were highly sensitive to house dust (13.5%) others aeroalergen pollen grains, were; rusian thistle (7.1%), Pigweed (5.4%), Cynodon Dactylon (4.9%), Pecan (4.8%), Ragweed Mix (4.8%), Rye grass (4.8%) other polen (32.4%). The molds: Candida (3.2%), Alternaria (2.7%), Rhizopus (3.6%), Penicillium (2.1%), Fusarium (2.1%), other molds (8.7%). The foods more important were: Wheat (21.3%), Cheese (10.0%), Shellfish Mix (10.0%), Pork (8.8%), Egg Yolk (7.5%).

[Hypersensitivity to common allergens in the central region of Coahuila]. / Estudio de hipersensibilidad a alergenos frecuentes en la región centro de Coahuila.

A retrospective review of 247 clinical files of patient that have responded to the office Allergy and immunology since 1990 to 1993 in Monclova, Coah, for allergy illness. This study was to determine the frequency of Aeroalergens and foods sensitization in Monclova, Coahuila, mediated Allergy Test Skin (intradermo reactions, and Prick) and MAST immuno Systems (Multiple Allergy System Test). The patients were highly sensitive to house dust (13.5%) others aeroalergen pollen grains, were: rusian thistle (7.1%), Pigweed (5.4%), Cynodon Dactylon (4.9%), Pecan (4.8%), Radweed Mix (4.8%), Rye grass (4.8%) other pollen (32.4%). The molds: Candida (3.2%), Alternaria (2.7%), Rhizopus (3.6%), Penicillium (2.1%), Fusarium (2.1%), other molds (8.7%). The foods more important were: wheat (21.3%), Cheese (10.0%), Shelfish Mix (10.0%), Pork (8.8%), Egg Yolk (7.5%).

Bilateral compartment syndrome after a long gynecologic operation in the lithotomy position.

Compartment syndrome occurred after a tubal anastomosis in a prolonged lithotomy position. This syndrome carries the risk of permanent neuromuscular and kidney damage. The pathophysiologic features of the syndrome are reviewed. Specific guidelines for the prevention and management of this syndrome in patients undergoing gynecologic procedures are presented.

Monoclonal antibodies to TEM-1 plasmid-mediated beta-lactamase.

At least 28 plasmid-mediated beta-lactamases have been described in gram-negative bacteria. To assess the relationship among these enzymes, we produced and characterized 28 murine monoclonal antibodies to the TEM-1 plasmid-mediated beta-lactamase. Radial immunodiffusion identified 3 monoclonal antibodies as immunoglobulin M (IgM), 18 as subclass IgG1, 2 as IgG2a, and 5 as IgG2b. Using a newly described enzyme immunoassay, cross-reactivity of 16 of these monoclonal antibodies was tested against 24 plasmid-determined beta-lactamases. The 16 monoclonal antibodies cross-reacted with TEM-2 and TLE-1 and, to a certain extent, SHV-1. Different levels of cross-reactivity were also observed with OXA-3 (11 of 16), OXA-7 (8 of 16), OXA-1 (2 of 16), OXA-6 (2 of 16), and AER-1 (2 of 16). Six monoclonal antibodies demonstrated partial neutralization of beta-lactamase activity. This study suggests that common epitopes are shared by nine biochemically distinct plasmid-mediated beta-lactamases. On the basis of cross-reactivities with these monoclonal antibodies, we identified four epitopes on TEM-1, TEM-2, TLE-1, and SHV-1 beta-lactamases.