VNS and pregnancy: A multicentric experience of four cases.

BACKGROUND: Vagus nerve stimulation system (VNS) has been employed worldwide as adjunctive therapy in drug-resistant epileptic patients. Only nine previous pregnancies with six-positive outcomes have been reported in women with epilepsy treated with VNS since 1998. AIMS OF THE STUDY: To communicate the experience of pregnancies in women treated with VNS in our country. METHODS: Clinical data of four female patients treated with VNS during pregnancy and delivery in five gestations is described. RESULTS: Four pregnancy outcomes were positive and one ended in spontaneous abortion, probably more related to the use antiepileptic drugs than VNS itself. Two births were vaginal and the other two with cesarean section. None of the complications during delivery were attributed to VNS. No teratogenicity was documented. CONCLUSIONS: Based on our experience VNS constitutes a safe therapy for the treatment of drug-resistant epilepsy in women of childbearing potential and during pregnancy and delivery. Larger series will be useful to confirm this finding.

Simultaneous microwave-assisted extraction of bioactive compounds from aged garlic.

In this work, the simultaneous extraction of bioactives (organosulfur compounds, such as S-allyl-L-cysteine (SAC), carbohydrates, such as neokestose and neonystose, and total phenolic compounds) from aged garlic has been optimized for the first time to obtain multifunctional extracts for further application as food ingredients. Analytical methods using liquid chromatography coupled to mass spectrometry (HPLC-MS) and by hydrophilic interaction liquid chromatography with evaporative light scattering detection (HILIC-ELSD) were also previously optimized. High sensitivity (limits of detection between 0.013 and 0.77 µg mL-1) and appropriate repeatability (< 12%) and accuracy (> 92%) for the analysis of bioactives were achieved. After selecting water as the extraction solvent and microwave-assisted extraction (MAE) as the most efficient technique, operation conditions were optimized using a Box-Behnken experimental design (60 min; 120 °C; 0.05 g mL-1; 1 cycle) to maximize the content of bioactives from different aged garlic samples. Regarding organosulfur compounds, only SAC (traces-2.32 mg g-1 dry sample) and cycloalliin (1.23-3.01 mg g-1 dry sample) were detected in all samples, while amino acids such as arginine (0.24-3.45 mg g-1 dry sample) and proline (0.43-3.91 mg g-1 dry sample) were, in general, the most abundant. Bioactive carbohydrates (from trisaccharides to nonasaccharides) were only detected in fresh garlic and aged garlic processed under mild conditions, whereas all garlic extracts showed antioxidant activity. The developed MAE methodology is shown as a successful alternative to other procedures for the simultaneous extraction of aged garlic bioactives intended by the food and nutraceutical industries, among others.

Exploitation of artichoke byproducts to obtain bioactive extracts enriched in inositols and caffeoylquinic acids by Microwave Assisted Extraction.

Byproducts from artichoke represent the majority of the mass collected from the plant and constitute an interesting source of bioactive compounds such as inositols and caffeoylquinic acids. In this work, a microwave assisted extraction (MAE) methodology was developed for the simultaneous extraction of these compounds from artichoke stalks, leaves, receptacles and external bracts. Optimal MAE conditions to maximize the extraction of these bioactives and the antioxidant activity were 97 °C, 3 min, ethanol:water (50:50, v/v). Moreover, a GC-MS methodology was also developed for the simultaneous determination of these compounds in a single run; optimal derivatization conditions were achieved using hexamethyldisilazane and N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane. Artichoke receptacle extracts were the richest in caffeoylquinic acids (28-35 mg g-1 dry sample), followed by the bracts (9-18 mg g-1 dry sample), while those from leaves showed the highest concentrations of inositols (up to 15 mg g-1 dry sample). Receptacle extracts also had the highest antioxidant activity (123 mg TE g-1 dry sample) and the greatest concentration of total phenolic compounds (47 mg GAE g-1 dry sample). Therefore, the developed methodology could be considered as a valuable procedure to obtain and characterize bioactive ingredients with industrial interest from artichoke byproducts, opening new routes of revalorization of artichoke agro-industrial residues.

Advances in structure elucidation of low molecular weight carbohydrates by liquid chromatography-multiple-stage mass spectrometry analysis.

Oligosaccharides are gaining importance because of their beneficial properties in human health. They normally appear in natural and synthetic products as complex mixtures of different monomeric units, glycosidic linkages and degrees of polymerization, being disaccharides and trisaccharides usually the most abundant ones. Although liquid chromatography-mass spectrometry is a useful technique for oligosaccharides analysis, the similarity of their structures makes difficult their characterization. Moreover, there is still scarce information about the relationship between carbohydrate chemical structure, mass spectra and chromatographic data. Then, in this work, chromatographic parameters for 23 disaccharides with different linkages and monomeric units (glucose, galactose, mannose and fructose) were determined using porous graphitized and hydrophilic interaction liquid chromatography columns. Moreover, diagnostic ions of these disaccharides obtained by tandem mass spectra (MS2) were established by stepwise linear discriminant analysis. The relationship between carbohydrate chemical structure and their chromatographic retention data and characteristic ions obtained by multiple-stage mass spectrometry (MSn) was successful in establishing some specific criteria that allowed the characterization of trisaccharides with different structural features.

Use of gas chromatography-mass spectrometry for identification of a new disaccharide in honey.

Gas chromatography-mass spectrometry has been used to separate and identify disaccharides of edible honey. According to the characteristic fragmentation behaviour of disaccharide TMS-oximes, fructofuranosyl-(2-1)-fructose (inulobiose) has been structurally characterized. Identification was carried out on the basis of retention time on two columns of different polarity and mass spectrometric analysis. Inulobiose was found in honeys of different origins for the first time, varying within 0.93 and 6.14 mg/g of honey. Its occurrence in honeys is discussed.

A new methodology based on GC-MS to detect honey adulteration with commercial syrups.

Honey adulterations can be carried out by addition of inexpensive sugar syrups, such as high fructose corn syrup (HFCS) and inverted syrup (IS). Carbohydrate composition of 20 honey samples (16 nectar and 4 honeydew honeys) and 6 syrups has been studied by GC and GC-MS in order to detect differences between both sample groups. The presence of difructose anhydrides (DFAs) in these syrups is described for the first time in this paper; their proportions were dependent on the syrup type considered. As these compounds were not detected in any of the 20 honey samples analyzed, their presence in honey is proposed as a marker of adulteration. Detection of honey adulteration with HFCS and IS requires a previous enrichment step to remove major sugars (monosaccharides) and to preconcentrate DFAs. A new methodology based on yeast (Saccharomyces cerevisiae) treatment has been developed to allow the detection of DFAs in adulterated honeys in concentrations as low as 5% (w/w).

Purification of lactulose from mixtures with lactose using pressurized liquid extraction with ethanol-water at different temperatures.

The viability of the purification of lactulose from a mixture with lactose [70:30 (w/w)] using pressurized liquid extraction (PLE) at 1500 psi for 30 min was studied. Different temperatures (from 40 to 130 degrees C) and proportions of ethanol:water (70:30, 80:20, 90:10, 95:5, and 100:0) as the extraction solvent were assayed. Lactose and lactulose were measured by gas chromatographic analysis as their trimethylsilyl derivatives. Data were fitted through multiple linear regressions to different quadratic models to describe both the extraction yield (in terms of mg of lactulose) and the purity of the lactulose extracted. The optimum extraction conditions provided by the model were as follows: extraction temperature, 40 degrees C; and solvent composition, 70:30 ethanol:water. PLE extraction under the optimized conditions was also applied to purify lactulose from lactose in a synthesis mixture. To our knowledge, this is the first time that PLE has been tested for extraction and purification of lactulose from its mixture with lactose; this technique showed several advantages over classical methods such as the short extraction time and the low solvent consumption.

Characterization of cyclitol glycosides by gas chromatography coupled to mass spectrometry.

Several cyclitol glycosides have been characterised as trimethylsilyl derivatives by their gas chromatographic (GC) retention data (linear retention indices) and electron impact mass spectrometric (MS) profiles. Both GC-MS results have been related to cyclitol glycosides structural features. Abundance ratios of characteristic m/z ions 133/129 and 260/265 have been proposed to distinguish glycosyl-inositols from glycosyl-methyl-inositols. These ratios in combination with the presence or absence of m/z 375 ion allowed the unequivocal characterization of cyclitol glycosides. These criteria have been applied to the characterization of new cyclitol glycosides in chickpea (Cicer arietinum) and adzuki bean (Vigna angularis) and in leaves of Coriaria myrtifolia and Coriaria ruscifolia.

Aetiology and resistance patterns of community-acquired pneumonia in León, Nicaragua.

We conducted a prevalence study to gain greater insight into the aetiology, bacterial resistance and risk factors for community-acquired pneumonia (CAP) in the region of León, Nicaragua. During the period from July 2002 to January 2005, all consecutive patients with signs and symptoms suggestive of CAP were included in the study. Sputum samples, paired serum samples and urinary samples were collected for the detection of respiratory pathogens. The most frequently identified pathogens were Streptococcus pneumoniae (17%), followed by Staphylococcus aureus (5%), Chlamydia pneumoniae (5%) and Mycoplasma pneumoniae (4%). Pseudomonas aeruginosa was cultured from 5% of patients. No pathogens were identified in 55%. All tested S. pneumoniae were sensitive to erythromycin and penicillin. In contrast, resistance of S. aureus to penicillin and erythromycin was high.

Application of guidelines on preoperative antibiotic prophylaxis in León, Nicaragua.

BACKGROUND: To determine adherence to the guideline for preoperative antibiotic use in Nicaragua. METHODS: An observational study in the University Hospital of León, Nicaragua. All surgical patients in the departments of general surgery, orthopaedics, gynaecology and obstetrics, and paediatrics during a four-week period were included. Patients with infections prior to surgery were excluded. Main outcome measures were the proportion of patients that received appropriate preoperative antibiotics based on wound classification, suspected pathogens, administered antibiotics (type and dose), therapy duration and timing according to the local protocol. RESULTS: In the study, 297 patients received a total of 395 antibiotics with 2595 doses for a total of 1087 days. Only 68% of patients received antibiotic prophylaxis for indications mentioned in the protocol. Antibiotics were given without indication or as treatment in 23%. In 9% of the cases no preoperative antibiotic therapy was given (no indication for 6%, but indicated for 3%). Of the 201 patients with an indication for prophylaxis, 25% received more antibiotic therapies than indicated. Antibiotic choice was discordant with the protocol in 69%, dose in 20%, and both the moment of administration and duration in 78%. Overall adherence was achieved in 7% of patients. Complete protocol violations were observed in 12%. The 243 patients in the prophylaxis group received 1707 doses, 83% of which were administered unnecessarily. CONCLUSION: Protocol violations are frequent in preoperative antibiotic prophylaxis in Nicaragua leading to considerable overprescription. Educational strategies to reinforce protocolised antibiotic use are essential for reducing costs and antibiotic resistance rates.

Characterization of goat colostrum oligosaccharides by nano-liquid chromatography on chip quadrupole time-of-flight mass spectrometry and hydrophilic interaction liquid chromatography-quadrupole mass spectrometry.

A detailed qualitative and quantitative characterization of goat colostrum oligosaccharides (GCO) has been carried out for the first time. Defatted and deproteinized colostrum samples, previously treated by size exclusion chromatography (SEC) to remove lactose, were analyzed by nanoflow liquid chromatography-quadrupole-time of flight mass spectrometry (Nano-LC-Chip-Q-TOF MS). Up to 78 oligosaccharides containing hexose, hexosamine, fucose, N-acetylneuraminic acid or N-glycolylneuraminic acid monomeric units were identified in the samples, some of them detected for the first time in goat colostra. As a second step, a hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-MS) methodology was developed for the separation and quantitation of the main GCO, both acidic and neutral carbohydrates. Among other experimental chromatographic conditions, mobile phase additives and column temperature were evaluated in terms of retention time, resolution, peak width and symmetry of target carbohydrates. Narrow peaks (wh: 0.2-0.6min) and good symmetry (As: 0.8-1.4) were obtained for GCO using an acetonitrile:water gradient with 0.1% ammonium hydroxide at 40°C. These conditions were selected to quantify the main oligosaccharides in goat colostrum samples. Values ranging from 140 to 315mgL(-1) for neutral oligosaccharides and from 83 to 251mgL(-1) for acidic oligosaccharides were found. The combination of both techniques resulted to be useful to achieve a comprehensive characterization of GCO.

Resistance of uropathogens in symptomatic urinary tract infections in León, Nicaragua.

Management of urinary tract infections (UTI) in Central America and especially Nicaragua, is complicated by the lack of knowledge about the antibiotic resistance of uropathogens. We conducted a prevalence study to gain more insight into the aetiology, bacterial resistance and risk factors for symptomatic UTI in the region of León, Nicaragua. In 2002, all consecutive patients with UTI symptoms and pyuria >/=10 WBC/hpf were admitted to the study. Positive cultures from midstream urine specimens were defined as >/=10(5) cfu/ml of a single uropathogen. Susceptibility tests were performed with disc diffusion tests using the Kirby-Bauer method and broth microdilution using National Committee for Clinical Laboratory Standards criteria both in León and a reference laboratory in Utrecht. A positive culture was present in 62 of 208 study subjects (30%). Escherichia coli (56%), Klebsiella spp. (18%) and Enterobacter spp. (11%) were the most frequent pathogens isolated. Presence of cystocele, incontinence and increasing age were risk factors for bacterial UTI. E. coli was least resistant to ceftriaxone, amikacin and nitrofurantoin (>90% susceptible). We observed high resistance rates in E. coli to amoxicillin (82%, MIC(90) 128 mg/l), trimethoprim-sulphamethoxazole (TMP-SMX) (64%, MIC(90) 32 mg/l), cephalothin (58%, MIC(90), 32 mg/l), ciprofloxacin (30%; MIC(90), 32 mg/l), amoxicillin/clavulanate (21%, MIC(90) 8 mg/l) and gentamicin (12%, MIC(90) 2 mg/l). Our results suggests that community acquired uropathogens in Nicaragua are highly resistant to many antimicrobial agents. The use of amoxicillin, trimethoprim-sulphamethoxazole and cephalothin against uropathogens needs to be reconsidered. High quinolone resistance rates among E. coli in Nicaragua gives cause for great concern.

Characterization of trimethylsilyl ethers of iminosugars by gas chromatography-mass spectrometry.

A combination of gas chromatographic retention data (linear retention indices) on two different stationary phases (100% methyl- and 50% phenylmethylsilicone) and electron impact mass spectrometric relative abundances for characteristic m/z ratios of 12 trimethylsilylated piperidine and pyrrolidine iminosugars are reported. These results have been related to their structural features and applied to the characterization of iminosugar composition of an Aglaonema treubii root extract. Seven iminosugars were detected in this extract, two of them were described for the first time.

Improvement of a gas chromatographic method for the analysis of iminosugars and other bioactive carbohydrates.

The analysis of derivatised iminosugars and other bioactive low molecular weight carbohydrates present at low concentrations in different vegetable extracts (hyacinth, mulberry and buckwheat) required the improvement of a previously developed gas chromatographic method. Among the different parameters optimized, the temperature of the injection port, evaluated for the first time, resulted to be the most important. Thus, 240 °C was chosen as a tradeoff to achieve the required volatility, to avoid degradation and to provide symmetric peaks for bioactive carbohydrates highly retained such as glycosyl inositols. GC-MS operating under selective ion monitoring (SIM) acquisition mode and GC-FID provided limits of detection and quantitation for the target compounds of 0.2 and 0.7 ng g(-1) and of 1 and 3 ng g(-1) on average, respectively. Therefore, both methodologies could be considered appropriate to extend the range of quantitation of these bioactives.

Derivatization of carbohydrates for GC and GC-MS analyses.

GC and GC-MS are excellent techniques for the analysis of carbohydrates; nevertheless the preparation of adequate derivatives is necessary. The different functional groups that can be found and the diversity of samples require specific methods. This review aims to collect the most important methodologies currently used, either published as new procedures or as new applications, for the analysis of carbohydrates. A high diversity of compounds with diverse functionalities has been selected: neutral carbohydrates (saccharides and polyalcohols), sugar acids, amino and iminosugars, polysaccharides, glycosides, glycoconjugates, anhydrosugars, difructose anhydrides and products resulting of Maillard reaction (osuloses, Amadori compounds). Chiral analysis has also been considered, describing the use of diastereomers and derivatives to be eluted on chiral stationary phases.

Increasing resistance in community-acquired urinary tract infections in Latin America, five years after the implementation of national therapeutic guidelines.

BACKGROUND: The worldwide increasing resistance to antibiotics has complicated antimicrobial treatment of urinary tract infections (UTIs), especially in Latin America. This study aimed to report the present etiology and antimicrobial susceptibility of UTIs, and the effects of the national guidelines for UTIs introduced in 2003. METHODS: Urine samples were collected from 304 patients with a clinical suspicion of UTI at the university hospital and primary health centers of León, Nicaragua. When bacterial growth was reported, antimicrobial susceptibility tests for nine frequently used antibiotics were performed. RESULTS: Ninety-one (29.9%) patients had a positive urine culture. The most frequently isolated microorganisms were Escherichia coli (n=44), Serratia spp (n=11), and Escherichia fergusonii (n=10). High resistance rates were observed in E. coli to ampicillin (61.4%), cefalothin (45.5%), trimethoprim-sulfamethoxazole (38.6%), ciprofloxacin (31.8%), and ceftriaxone (20.5%). Amikacin and nitrofurantoin were the only drugs to which >90% of E. coli were susceptible. E. fergusonii and Serratia spp showed comparable high resistance patterns. Thirteen strains (29.5%) of E. coli were suspected to produce extended-spectrum beta-lactamase (ESBL). CONCLUSIONS: Resistance rates in community-acquired UTIs in Nicaragua are increasing. The introduction of therapeutic guidelines with ceftriaxone recommended for upper UTIs and nitrofurantoin for lower UTIs, has led to increasing resistance against both antibiotics. The emergence of ESBL-producing E. coli is worrisome, along with the appearance of Serratia spp in the population.