Direct oral challenge for immediate and non-immediate beta-lactam allergy in children: A real-world multicenter study

BACKGROUND

Allergy to beta-lactam antibiotics (BLA) is frequently suspected in children, but a drug provocation test (DPT) rules it out in over 90% of cases. Direct oral DPT (DODPT), without skin or other previous tests, is increasingly been used to delabel non-immediate BLA reactions. This real-world study aimed to assess the safety and effectiveness of DODPT in children with immediate and non-immediate reactions to BLAs.

METHODS

Ambispective registry study in children (<15 years), attended between 2016 and 2023 for suspected BLA allergy in 15 hospitals in Spain that routinely perform DODPT.

RESULTS

The study included 2133 patients with generally mild reactions (anaphylaxis 0.7%). Drug provocation test with the implicated BLA was performed in 2014 patients (94.4%): 1854 underwent DODPT (86.9%, including 172 patients with immediate reactions). One hundred forty-five (7.2%) had symptoms associated with DPT, although only four reactions were severe: two episodes of anaphylaxis and two of drug-induced enterocolitis syndrome, which resolved rapidly with treatment. Of the 141 patients with mild reactions in the first DPT, a second DPT was considered in 87 and performed in 57, with 52 tolerating it without symptoms. Finally, BLA allergy was ruled out in 90.9% of the sample, confirmed in 3.4%, and remained unverified, usually due to loss to follow-up, in 5.8%.

CONCLUSIONS

Direct oral DPT is a safe, effective procedure even in immediate mild reactions to BLA. Many reactions observed in DPT are doubtful and require confirmation. Severe reactions are exceptional and amenable to treatment. Direct oral DPT can be considered for BLA allergy delabeling in pediatric primary care.

Epidemiology of pediatric parapneumonic pleural effusion during 13-valent pneumococcal conjugate vaccine implementation

INTRODUCTION

The reported incidence of parapneumonic pleural effusion, including empyema, has shown fluctuations in the last decades. It has been related to the implementation of different types of conjugate pneumococcal vaccines.

METHODS

We have retrospectively reviewed data from all 10 public hospitals in Alicante Province (Spain) covering a population of 279,000 children under 15 years of age, between 2010 and 2018. Effusions less than 10 mm (PE-) and those of 10 mm or more (PE+) were separated.

RESULTS

A total of 366 episodes of parapneumonic pleural effusion have been analyzed, 178 PE- (48.6%) and 188 PE+ (51.4%), with a median age of 4 years (interquartile range: 2-7 years) and marked seasonality with the maximum in winter and the minimum in summer. A culture proven bacterial agent was identified in 34 patients (9.3%), mainly Streptococcus pneumoniae (24 patients) followed by Streptococcus pyogenes (7 patients). The most frequent S. pneumoniae serotype was 19A (6 patients) and 3 vaccine failures were observed. The mean annual incidence rate was 14.3 cases per 100,000 children under 15 years of age (7.0 for PE- and 7.3 for PE+). No significant changes were observed in incidence over time, but noticeable differences in incidence were observed in different health departments.

CONCLUSIONS

We have not found temporal variations in incidence of parapneumonic effusion despite the implementation of the 13-valent pneumococcal conjugate vaccine. The unexplained disparity in incidence between close departments is noteworthy.

Relationship between thyroid disfunction and fertility

Thyroid dysfunctions have been associated with maternal-fetal development abnormalities. The evidence about the influence that thyroid dysfunctions can have on delayed conception is not very numerous. However, the benefit of a systematic screening of such alterations is not well established. The main objective is to determine if thyroid dysfunctions are associated with delays in conception in patients treated in an obstetric clinic.

Population-Based Cohort of Children With Parapneumonic Effusion and Empyema Managed With Low Rates of Pleural Drainage

Introduction: The most appropriate treatment for parapneumonic effusion (PPE), including empyema, is controversial. We analyzed the experience of our center and the hospitals in its reference area after adopting a more conservative approach that reduced the use of chest tube pleural drainage (CTPD). Methods: Review of the clinical documentation of all PPE patients in nine hospitals from 2010 to 2018. Results: A total of 318 episodes of PPE were reviewed; 157 had a thickness of <10 mm. The remaining 161 were 10 mm or thicker and were subdivided into three increasing sizes: PE+1, PE+2, and PE+3. There was a strong relationship between the size of the effusion and complicated effusion/empyema, defined by its appearance on imaging studies or by the physical or bacteriological characteristics of the pleural fluid. The size of effusion was also strongly related to the duration of fever and intravenous treatment and was the best independent predictor of the length of hospital stay (LHS) (p < 0.001). CTPD was placed in 2.9% of PE+1 patients, 19.3% of PE+2, and 63.9% of PE+3 (p < 0.001). The referral of patients with PE+1 decreased over time (p = 0.033), as did the use of CTPD in the combined PE+1/PE+2 group (p = 0.018), without affecting LHS (p = 0.814). There were no changes in the use of CTPD in the PE+3 group (p = 0.721). Conclusions: The size of the PPE is strongly correlated with its severity and with LHS. Most patients can be treated with antibiotics alone.

Microchip in situ electrosynthesis of silver metallic oxide clusters for ultra-FAST detection of galactose in galactosemic newborns' urine samples

This work describes for the first time the coupling of microfluidic chips (MC) to electrosynthetized silver metallic oxide clusters (AgMOCs). As an early demonstration of this novel approach, the ultrafast detection of galactose in galactosemic newborns' urine samples is proposed. AgMOCs were in situ electrosynthetized on integrated microchip platinum electrodes using a double pulse technique and characterized in full using scanning electronic microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques revealing the presence of silver oxides and electrocatalysis towards galactose as a galactosemia biomarker. Galactose detection in galactosemic newborns' urine samples proceeded in less than 30 s, differentiating between ill and healthy urine samples and requiring negligible urine sample consumption. The significance of the newborns' urine samples confirmed the analytical potency of the MC-AgMOCs approach for future implementation of screening for rare disease diagnosis such as galactosemia.

Peripheral Lymphocytes, Obesity, and Metabolic Syndrome in Young Adults: An Immunometabolism Study

BACKGROUND

Obesity is characterized by a low-intensity chronic inflammatory process in which immune system cells interact in a complex network, which affects systemic metabolic processes. This raises interest in analyzing possible changes in the proportions of immune system cells in individuals with obesity with and without metabolic syndrome (MS), in relation to their body composition.

METHODS

Circulating cells were analyzed with flow cytometry in young adults: monocytes, granulocytes, lymphocytes (T, B, and natural killer [NK]), TCD4⁺CD62^-, TCD8⁺CD28^-, and naive and memory cells of TCD3⁺ and TCD4⁺. Body composition was obtained by bioelectrical impedance analysis and dual-energy X-ray absorptiometry, and metabolic parameters.

RESULTS

A total of 169 persons were evaluated: 20% presented normal body mass index (BMI); 49% was overweight, and 31% had obesity; 28% had MS. It was observed that with an increase in BMI and visceral adipose tissue increase (VATI), body composition and biochemical variables were negatively altered. With regard to cell subpopulations, total lymphocytes increased and granulocytes and NK lymphocytes decreased in patients with MS and VATI. Memory cells increased with BMI and VATI. In individuals with MS, monocytes, and NK lymphocytes comprised a negative association with VAT, fat mass, and skeletal muscle mass (SMM). In individuals with MS and VATI, a negative correlation was observed between monocytes and SMM.

CONCLUSIONS

Significant changes were detected in the subpopulations of lymphocytes, suggesting that weight gain, SMM, and VAT accumulation gave rise to immunological changes at the peripheral level, and the presence of increased memory cells could be related to low-intensity chronic inflammation.

Correction: Microchip in situ electrosynthesis of silver metallic oxide clusters for ultra-FAST detection of galactose in galactosemic newborns' urine samples

Correction for 'Microchip in situ electrosynthesis of silver metallic oxide clusters for ultra-FAST detection of galactose in galactosemic newborns' urine samples by Laura García-Carmona et al., Analyst, 2016, 141, 6002-6007.

Spanish validation of the PAS-ADD Checklist Questionnaire for people with intellectual disabilities for Spanish population

BACKGROUND

The Psychiatric Assessment Schedule for Adult with Developmental Disability (PAS-ADD) is an international reference tool for the diagnosis and assessment of mental health problems and behavioural disorders among people with intellectual disabilities. Although the original PAS-ADD instrument has been validated in the Spanish language, the shorter PAS-ADD Checklist has yet not been validated. The aim of this study is to validate the PAS-ADD Checklist for the Spanish population.

METHODS

The PAS-ADD Checklist Questionnaire was administered to 208 adults with intellectual disabilities at a vocational centre in Madrid, Spain. The psychometric analyses included internal consistency, inter-rater and test-retest reliability, Varimax rotation factor analysis for construct validity, criterion validity and feasibility.

RESULTS

The Cronbach's alpha was 0.80 for the overall questionnaire and between 0.40 and 0.79 for the subscales. The Kappa coefficients for test-retest and inter-rater reliability were between 0.66 and 0.80. Varimax rotation factor analysis showed five well-defined factors. The Kappa coefficients for criterion validity were between 0.30 and 0.70. Feasibility was also good.

CONCLUSIONS

The PAS-ADD Checklist is a feasible and reliable instrument for carrying out initial assessment of the mental health status of adults with intellectual disabilities, referring cases to more specialised diagnosis and treatment.

Aligned copper nanowires as a cut-and-paste exclusive electrochemical transducer for free-enzyme highly selective quantification of intracellular hydrogen peroxide in cisplatin-treated cells

The role and reliable quantification of intracellular hydrogen peroxide during cancer therapy constitutes an unexplored and fascinating application. In this work, we report the fabrication of vertically aligned copper nanowires (v-CuNWs) using electrosynthesis on templates, and their application as a cut-and-paste exclusive and flexible electrochemical transducer. This easily adaptable electrodic platform is demonstrated for a fast, simple and free-enzyme selective quantification of intracellular hydrogen peroxide in Cisplatin-treated human renal HK-2 cells. The v-CuNWs sensor was compared with an HRP-enzyme-based biosensor showing excellent correlation and indicates the good selectivity and analytical performance of the v-CuNWs. This sensing approach opens novel avenues for monitoring cell death processes and shows the potential of H₂O₂ as a cellular damage biomarker, with a clear potency for further developments for in vitro diagnosis and its implication in cancer therapy.

Vertically-Oriented and Shape-Tailored Electrocatalytic Metal Nanowire Arrays for Enzyme-Free Galactosemia Rapid Diagnosis

Metallic catalytic nanowires such as nickel and copper nanowires (NWs) for electrochemical detection of carbohydrates involved in metabolic rare diseases are proposed. NWs were electrodeposited using a polycarbonate membrane template, which was cut with the desired shape, stuck in double-sided adhesive tape, pasted into a non-conductive substrate and in situ removed. This simple and versatile approach allowed to obtain NWs vertically oriented (v-NWs), which are contained in the double-sided adhesive tape, becoming highly versatile. The high specific surface of working electrode in which the transduction is supported exclusively by the nanomaterial yielded a high analytical performance [extremely low fouling for galactose (RSD<2 %; n=25)]. Likewise, v-NWs exhibited a superior analytical performance with respect to commercial sputtered thick-film electrodes showing also a clear advantage related with the price, as well as with non-need clean room facilities. The analytical potency of the new approach was clearly demonstrated towards the fast and reliable diagnosis of galactosemia using precious newborn urine samples compared to standard clinical diagnosis. These results revealed new opportunities for future enzyme-free diagnosis and development of future point-of-care applications.

Genetic predisposition to albuminuria is associated with increased arterial stiffness: role of elastin

BACKGROUND AND PURPOSE

The Munich Wistar Frömter (MWF) rat strain represents an experimental model to study cardiovascular alterations under conditions of progressive albuminuria. The aim of this study was to evaluate the association between genetic predisposition to albuminuria and the development of arterial stiffness and/or vascular remodelling.

EXPERIMENTAL APPROACH

Experiments were performed in mesenteric arteries from 12-week-old MWF, Wistar Kyoto (WKY) and consomic MWF-6(SHR) and MWF-8(SHR) rats in which chromosomes 6 or 8 associated with albuminuria from MWF were replaced by the respective chromosome from spontaneously hypertensive rats (SHR).

KEY RESULTS

Incremental distensibility, wall stress and strain were reduced, and arterial stiffness was significantly increased in albuminuric MWF compared with WKY. Albuminuria suppression in both consomic strains was associated with lower β-values in MWF-8(SHR) and MWF-6(SHR) compared with MWF. Moreover, elastin content was significantly lower in MWF external elastic lamina compared with WKY and both consomic strains. In addition, a reduction in arterial external and internal diameter and cross-sectional area was detected in MWF compared with WKY, thus exhibiting an inward hypotrophic remodelling. However, these alterations remained unchanged in both consomic strains.

CONCLUSION AND IMPLICATIONS

These data demonstrate that albuminuria in MWF is associated with increased arterial stiffness due to a reduction of elastin content in the external elastic lamina. Moreover, inward hypotrophic remodelling in MWF is not directly associated with albuminuria. In contrast, we demonstrated that two major genetic loci affect both the development of albuminuria and arterial stiffness, thus linking albuminuria and impairment of mechanical properties of resistance arteries.

Antioxidant capacity index based on gold nanoparticles formation. Application to extra virgin olive oil samples

A simple gold nanoparticles (AuNPs) based colorimetric assay for the antioxidant activity determination has been developed. The AuNP formation is mediated by extra virgin olive oil (EVOO's) endogenous polyphenols; the reaction is described by a sigmoidal curve. The ratio KAuNPs/Xc(50) (slope of the linear part of the sigmoid/concentration at half value of the absorbance) was found to be the optimal parameter to report the antioxidant capacity with respect to the single KAuNPs or Xc(50) values. The obtained data demonstrated that the compounds with ortho-diphenols functionality are most active in reducing gold (III) to gold (0). Thus, intermediate activity was found for gallic acid, while tyrosol (mono-phenols) had a significant lower activity than the others antioxidant compounds (at least one order of magnitude). In the analysis of olive oil samples, a significant correlation among classical methods used to determine antioxidant activity and the proposed parameter was found with R values in the 0.96-0.97 range.

Association between an inflammatory-nutritional index and nutritional status in cancer patients

INTRODUCTION

Cachexia is a multifatorial syndrome characterized by loss of body weight, fat and muscle, increasing morbidity and mortality. The use of an index accounting for both serum albumin and C Reactive Protein levels could make early identification of cachexia easier.

OBJECTIVE

To evaluate the variation of an inflammatory nutritional index related to nutritional status in cancer patients.

METHODS

Cross sectional study including patients with gastrointestinal and lung cancer of a public chemotherapy service in Brazil. Serum albumin and C Reactive Protein were measured and the nutritional status was defined by Subjective Global Assessment. Statistical analyses were performed using Stata 9.2(TM).

RESULTS

A total of 74 patients were evaluated, 58.1% of them were male, mean age 63.4 ± 11.9 years old. Gastrointestinal cancer was the most prevalent type (71.6%). Only 13.7% of the patients were well nourished and 21.9% were severely malnourished. C Reactive Protein significantly increased according to nutritional status decline (p=0.03). When the albumin from patients with systemic inflammation was evaluated, there was no significant variation in relation to nutritional status (p=0.06). The Inflammatory Nutritional Index significantly varied in relation to nutritional status independent of the systemic inflammation (p=0.02).

CONCLUSIONS

Inflammatory Nutritional Index can be an adjuvant way for biochemical nutritional assessment and follow up in cancer patients with systemic inflammation.

Effect of Saccharomyces strains on the quality of red wines aged on lees

Ageing on lees involves ageing the wine in contact with yeast cells after fermentation. If combined with the addition of oak chips, it can soften the wood flavour and increase the aromatic complexity of wine. The aim of the present work is to optimise both ageing techniques through selection of an adequate Saccharomyces cerevisiae strain. The study lasted 6 months and content of polysaccharides, anthocyanins, proanthocyanidins, volatile compounds, colour parameters and sensory analysis, were periodically evaluated. Among the strains tested, G37 showed the highest release of polysaccharides (24.4±5.5 mg l(-1)). Vanillin, syringaldehyde and furfuryl alcohol increased with ageing time in 7VA2 treatment. The wine aged with CTPL14 strain presented fewer monomeric and oligomeric proanthocyanidins (12.4±0.6 and 83.4±8.3 mg l(-1), respectively), and showed the lowest astringency and bitterness sensations. Results show an improvement in the sensory profile of the red wine aged with a combination of these two techniques.

Formation of pyranoanthocyanins by Schizosaccharomyces pombe during the fermentation of red must

Schizosaccharomyces pombe is a non-Saccharomyces yeast strain that can ferment grape musts with high sugar contents - but it also has other metabolic and physiological properties that render it of great interest to wine biotechnologists. This work compares the production of pyranoanthocyanins by S. pombe, Saccharomyces cerevisiae and Saccharomyces uvarum during fermentation. Total pyranoanthocyanins ranged from 11.9 to 19.4 mg/l depending on the strain of S. pombe used. On average, S. pombe produced more pyruvic acid than did either Saccharomyces species; as a consequence it also formed more vitisin A-type pigments. S. pombe 938 produced the largest quantity of vitisin A (11.03±0.82 mg/l). The formation of large amounts of pyranoanthocyanins intensifies the post-fermentation colour of wines somewhat, a phenomenon that helps them maintain their colour over ageing as the natural grape anthocyanins become degraded. Some of the S. pombe strains showed hydroxycinnamate decarboxylase activity, which favours the formation of vinylphenolic pyranoanthocyanins. Fermentation with S. pombe therefore provides an interesting way of increasing the overall pyranoanthocyanin content of red wines, and of stabilising their colour during ageing.

Long-term nutritional assessment of patients with severe short bowel syndrome managed with home enteral nutrition and oral intake

BACKGROUND

Parenteral nutrition (PN) is used to control the nutritional state after severe intestinal resections. Whenever possible, enteral nutrition (EN) is used to promote intestinal rehabilitation and reduce PN dependency. Our aim is to verify whether EN + oral intake (OI) in severe short bowel syndrome (SBS) surgical adult patients can maintain adequate nutritional status in the long term.

METHODS

This longitudinal retrospective study included 10 patients followed for 7 post-operative years. Body mass index (BMI), percentage of involuntary loss of usual body weight (UWL), free fat mass (FFM), and fat mass (FM) composition assessed by bioelectric impedance, and laboratory tests were evaluated at 6, 12, 24, 36, 48, 60, 72, and 84 months after surgery. Energy and protein offered in HPN and at long term by HEN+ oral intake (OI), was evaluated at the same periods. The statistical model of generalized estimating equations with p < 0,05 was used.

RESULTS

With long term EN + OI there was a progressive increase in the UWL, a decrease in BMI, FFM, and FM (p < 0,05). PN weaning was possible in eight patients. Infection due to central venous catheter (CVC) contamination was the most common complication (1.2 episodes CVC/patient/year). There was an increase in energy and protein intake supply provided by HEN+OI (p < 0.05). All patients survived for at least 2 years, seven for 5 years and six for 7 years of follow-up.

CONCLUSIONS

In the long term SBS surgical adult patients fed with HEN+OI couldn't maintain adequate nutritional status with loss of FM and FFM.

High NIR-purity index single-walled carbon nanotubes for electrochemical sensing in microfluidic chips

Single-walled carbon nanotubes (SWCNTs) should constitute an important natural step towards the improvement of the analytical performance of microfluidic electrochemical sensing. SWCNTs inherently offer lower detection potentials, higher surfaces and better stability than the existing carbon electrodes. However, pristine SWCNTs contain some carbonaceous and metallic impurities that influence their electrochemical performance. Thus, an appropriate processing method is important for obtaining high purity SWCNTs for analytical applications. In this work, a set of 0.1 mg mL(-1) SWCNT dispersions with different degrees of purity and different dispersants (SDBS; pluronic F68 and DMF) was carefully characterized by near infrared (NIR) spectroscopy giving a Purity Index (NIR-PI) ranging from 0.039 to 0.310. The highest purity was obtained when air oxidized SWCNTs were dispersed in SDBS, followed by centrifugation. The SWCNT dispersions were utilized to modify microfluidic chip electrodes for the electrochemical sensing of dopamine and catechol. In comparison with non-SWCNT-based electrodes, the sample with the highest NIR-PI (0.310) exhibited the best analytical performance in terms of improved sensitivity (3-folds higher), very good signal-to-noise ratio, high resistance-to-fouling in terms of relative standard deviation (RSD 7%; n = 15), and enhanced resolution (2-folds higher). In addition, very well-defined concentration dependence was also obtained with excellent correlation coefficients (r ≥ 0.990). Likewise, a good analytical sensitivity, suitable detection limits (LODs) and a very good precision with independence of the concentration assayed (RSDs ≤ 5%) was achieved. These valuable features indicate the suitability of this material for quantitative analysis. NIR-PI and further TEM and XRD characterization demonstrated that the analytical response was driven and controlled by the high NIR-PI of the SWCNTs used. The significance of this work is the demonstration for the first time of the sensitivity-purity relationship in SWCNT microfluidic chips. A novel and valuable analytical tool for electrochemical sensing has been developed: SWCNTs with high purity and a rich surface chemistry with functional groups, both essential for analytical purposes. Also, this work helps to better understand the analytical potency of SWCNTs coupled to microfluidic chips and it opens new gates for using these unique dispersions in real-world applications.

Resting energy expenditure in white and non-white severely obese women

This study aimed to compare the resting energy expenditure (REE) of white and non-white severely obese Brazilian women. REE was examined in 83 severely obese Brazilian women (n = 58 white and 25 non-white) with mean (+/- SD) age 42.99 +/- 11.35 and body mass index 46.88 +/- 6.22 kg/m(2) who were candidates for gastric bypass surgery. Body composition was assessed by air displacement plethysmography (ADP) BOD PODO body composition system (Life Measurement Instruments, Concord, CA) and REE was measured, under established protocol, with an open-circuit calorimeter (Deltatrac II MBM-200, Datex-Ohmeda, Madison, WI, USA). There was no significant difference between the REE of white and non-white severely obese women (1,953 +/- 273 and 1,906 +/- 271 kcal/d, respectively; p = 0.48). However, when adjusted for fat free mass (MLG), REE was significantly higher in nonwhite severely obese women (difference between groups of 158.4 kcal, p < 0.01). REE in white women was positively and significantly correlated to C-reactive protein (PCR) (r = 0.418; P < 0.001) and MLG (r = 0.771; P < 0.001). In the non-white women, REE was only significantly correlated to MLG (r = 0.753; P < 0.001). The multiple linear regression analysis showed that skin color, MLG and PCR were the significant determinants of REE (R(2) = 0.55). This study showed that, after adjustment for MLG, non-white severely obese women have a higher REE than the white ones. The association of body composition inflammation factors and REE in severely obese Brazilian women remains to be further investigated.

Factors modulating fibrates response: therapeutic implications and alternative strategies

Peroxisome proliferator-activated receptor alpha (PPARalpha) regulates transcription of genes involved both in lipid and glucose metabolism as well as in inflammation. Fibrates are PPARalpha ligands used to normalize lipid and glucose parameters and exert antiinflammatory effects. In fact, fibrates have already been demonstrated to benefit metabolic syndrome, type 2 diabetes and cardiovascular diseases. This article reviews the mechanism of action and the functional roles of fibrates, emphasizing the factors modulating their capacity to activate PPARalpha and affecting their effectiveness. These factors may possibly explain the findings obtained in animal studies and clinical trials with fibrates which showed either untoward effects and/or inefficient hypolipidemic action of PPARalpha activation. We also discuss briefly the natural and synthetic agonists of PPARalphawhich are currently being developed and supposedly display greater effectiveness and fewer adverse effects than fibrates.

A swimming pool-related outbreak of pharyngoconjunctival fever in children due to adenovirus type 4, Gipuzkoa, Spain, 2008

An outbreak of pharyngoconjunctival fever affecting 59 children was detected in a municipality of northern Spain in July 2008. The outbreak was related to insufficient doses of water disinfectant in the municipal swimming pool. Adenovirus was detected in the pharyngeal swabs of five of six affected children and the four strains that were sequenced were all Adenovirus type 4.

Towards lab-on-a-chip approaches in real analytical domains based on microfluidic chips/electrochemical multi-walled carbon nanotube platforms

"Lab-on-a-chip" approaches based on the novel marriage between an electrokinetic microfluidic platform and nanotechnology is proposed for analytical domains. Conceptually, the analytical challenges are linked with the analytical promises offered from the integration of lab-on-a-chip and nanotechnologies. The analytical suitability of the electrokinetic microfluidic platform with multi-walled carbon nanotubes as detectors is proposed based on its dual format/use as a flow and separation system, independently. Two relevant applications of high significance, determination of total isoflavones and fast detection of antioxidant profiles were chosen to demonstrate their analytical potential. For both analytical uses, the target challenges, the strategy proposed, the expected role of microfluidics and carbon nanotubes and future prospects are discussed and demonstrated. A good analytical performance of the proposed microfluidic platform in terms of reliability, versatility and fast analytical solutions is demonstrated.

Food analysis on microfluidic devices using ultrasensitive carbon nanotubes detectors

Microfluidic devices using carbon nanotube (CNT) materials (single-walled and two multiwalled (MWCNT)) for the analysis of selected analyte groups of significance in foods such as dietary antioxidants, water-soluble vitamins, vanilla flavors, and isoflavones involved in representative food samples have been explored for the first time. Ultrafast separations resulted in well-defined and resolved peaks with enhanced voltammetric current in comparison with those obtained from unmodified screen-printed electrodes, turning MWCNT into an ideal material for electrochemical sensing in food analysis. Resolution was improved by a factor of 2, and sensitivity was dramatically enhanced with amplification factors toward calibration slopes from 4- to 16-fold. In both qualitative and quantitative domains, this impressive performance of CNTs integrated on microfluidics allowed solving specific challenges in food environments such as the direct detection of analytes in complex natural samples and unambiguous analytes in the control of fraud, which was not possible on nonmodified surfaces, avoiding the integration of complex preconcentration steps on these microdevices. The use of these unique materials in microfluidics for food analysis has opened new expectations in "lab-on-a-chip" domains.

Different topologies for a herding model of opinion

Understanding how opinions spread through a community or how consensus emerges in noisy environments can have a significant impact on our comprehension of social relations among individuals. In this work a model for the dynamics of opinion formation is introduced. The model is based on a nonlinear interaction between opinion vectors of agents plus a stochastic variable to account for the effect of noise in the way the agents communicate. The dynamics presented is able to generate rich dynamical patterns of interacting groups or clusters of agents with the same opinion without a leader or centralized control. Our results show that by increasing the intensity of noise, the system goes from consensus to a disordered state. Depending on the number of competing opinions and the details of the network of interactions, the system displays a first- or a second-order transition. We compare the behavior of different topologies of interactions: one-dimensional chains, and annealed and complex networks.

Oral-health workshop targeted at 0-5-yr. old deprived children's parents and caregivers: effect on knowledge and practices

One-session oral-health workshop was targeted at 770 parents and 60 caregivers of 0-5-year-old low-income children. Lower plaque scores (Silness & Löe-modified index) were observed in test-group-(TG) children after 1 and 6-months (Median=0) than control-group-(CG) (Median=1)(p<0.05), with a significant improvement from baseline among the TG (p<0.05). The questionnaire showed improvement in the TG parents/caregivers' knowledge after 1- 6-months regarding white-spot lesion visual recognition; with respect to the practices, these improved after 1-6 but decreased after 6-months.

CE microchips: An opened gate to food analysis

CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.

Electrochemical valveless flow microsystems for ultra fast and accurate analysis of total isoflavones with integrated calibration

A novel strategy integrating methodological calibration and analysis on board on a planar first-generation microfluidics system for the determination of total isoflavones in soy samples is proposed. The analytical strategy is conceptually proposed and successfully demonstrated on the basis of (i) the microchip design (with the possibility to use both reservoirs), (ii) the analytical characteristics of the developed method (statically zero intercept and excellent robustness between calibration slopes, RSDs < 5%), (iii) the irreversible electrochemical behaviour of isoflavone oxidation (no significant electrode fouling effect was observed between calibration and analysis runs) and (iv) the inherent versatility of the electrochemical end-channel configurations (possibility of use different pumping and detection media). Repeatability obtained in both standard (calibration) and real soy samples (analysis) with values of RSD less than 1% for the migration times indicated the stability of electroosmotic flow (EOF) during both integrated operations. The accuracy (an error of less than 6%) is demonstrated for the first time in these microsystems using a documented secondary standard from the Drug Master File (SW/1211/03) as reference material. Ultra fast calibration and analysis of total isoflavones in soy samples was integrated successfully employing 60 s each; enhancing notably the analytical performance of these microdevices with an important decrease in overall analysis times (less than 120 s) and with an increase in accuracy by a factor of 3.

A fast and reliable route integrating calibration and analysis protocols for water-soluble vitamin determination on microchip-electrochemistry platforms

A novel analytical route to determine water-soluble vitamins (B group and C) using single channel microchip-electrochemistry platforms is presented. The electrochemical detection protocol was carefully optimized, and it was shown that it was crucial to use 1 M nitric acid in the detector compartment to detect folic acid. A phosphate buffer (pH 6, 10 mM) and a separation voltage of 2 kV gave the complete separation of vitamins in less than 130 s, with good reproducibility (RSDs less than 10%) and accuracy (error less than 9%). In addition, a methodological innovation integrating calibration and analysis of water-soluble vitamins on the chip is also proposed. The strategy consisted in sequentially using both reservoirs (named calibration and analysis reservoirs) as well as a calibration factor (defined as signal/concentration of analyte). The analytical route required 350 s in the overall protocol (employing 130 s in calibration plus 130 s in analysis), an improvement over the times used in both conventional and microchip protocols.

Tetrahydrobiopterin stimulates L-DOPA release from striatal tissue

In the present study we have analyzed the effect of tetrahydrobiopterin (BH4) essential cofactor for tyrosine hydroxylase and nitric oxide synthase, on the 3,4-dihydroxyphenylalanine (L-DOPA) release from in vitro incubated striatal tissue. dl-6-methyl-5,6,7,8 tetrahydropterine (6-MPH4)-stimulated L-DOPA release in a concentration-dependent manner in the range from 25 to 100 microM. At these concentrations 6-MPH4 did not have any effect on dopamine release. Presence of Nomega-Nitro-L-arginine methyl ester (L-NAME, 200 microM), a nitric oxide synthase inhibitor, but not of alpha-methyl-rho-tyrosine (alpha-MPT, 100 microM), a tyrosine hydroxylase inhibitor, blocked L-DOPA release induced by 6-MPH4 (200 microM). Also, the addition to the incubation medium of melatonin (MEL, 300 microM), which is a scavenger of NO and other free radicals, blocked the L-DOPA release induced by 6-MPH4 (200 microM) but this effect did not occur with the addition of the peroxynitrite scavenger uric acid (UA, 300 microM). Sodium nitroprusside (SNP, 100 muM), a NO generator and l-DOPA releaser as previously reported, potentiated the L-DOPA releasing effect of 6-MPH4 (200 microM) which was also blocked by melatonin. In summary 6-MPH4 stimulates L-DOPA release from striatal fragments incubated in vitro by a mechanism which involves NO or other free radicals derived from NO but not peroxynitrite.

Fast and simultaneous detection of prominent natural antioxidants using analytical microsystems for capillary electrophoresis with a glassy carbon electrode: A new gateway to food environments

This paper examines for the first time the analytical possibilities of fast and simultaneous detection of prominent natural antioxidants including examples of flavonoids and vitamins using a CE microchip with electrochemical detection (ED). Unpinched injection conditions, zone electrophoretic separation and amperometric detection were carefully assayed and optimised. Analysis involved the zone electrophoretic separation of arbutin, (+)-catechin and ascorbic acid in less than 4 min using a borate buffer (pH 9.0, 50 mM), employing 2 kV as the separation voltage and +1.0 V as the detection potential. In addition, the separation of different 'couples' of natural antioxidants of food significance including (+)-catechin and ascorbic acid, (+)-catechin and rutin, as well as arbutin and phlorizdin is proposed. To demonstrate the potential and future role of CE microsystems, analytical possibilities and a new route in the raw sample analysis are presented. The preliminary results obtained allow the proposal of CE-ED microchips as a real gateway to microanalysis in foods.

Effect of intracerebroventricular injection of lipopolysaccharide on the tuberoinfundibular dopaminergic system of the rat

Numerous studies indicate that monoaminergic systems are sensitive to both peripheral and central inflammatory stimuli, and in particular dopaminergic neurons in the nigrostriatal system degenerate after local injection of lipopolysaccharide (LPS). However, data about the response of other dopaminergic groups to local inflammation are very sparse. In this study, we have examined the effect of i.c.v. injection of LPS on the tuberoinfundibular dopaminergic (TIDA) system by using biochemical and morphological parameters. Our results show that 6 h after i.c.v. injection of LPS, in parallel to a transient and intense immunoreaction to interleukin-1beta in arcuate microglial cells, there is a decrease in tyrosine hydroxylase (TH) activity in the median eminence and in the number of TH- and TH mRNA-positive cells in the arcuate nucleus, and at 12 h, an increase of prolactin levels in serum. Posterior changes were found in the TH mRNA labeling pattern, mostly in the ventrolateral region of the arcuate nucleus, but they were not accompanied by any changes in TH activity and immunoreactivity and TH-cell count. This suggests that the TIDA system is functionally susceptible to local inflammation, but the effects are transient and do not induce neurodegeneration.