Retrospective definition of reaction risk in Italian children with peanut, hazelnut and walnut allergy through component-resolved diagnosis.

BACKGROUND: Serum IgE evaluation of peanut, hazelnut and walnut allergens through the use of component-resolved diagnosis (CRD) can be more accurate than IgE against whole food to associate with severe or mild reactions. OBJECTIVES: The aim of the study was to retrospectively define the level of reaction risk in children with peanut, hazelnut and walnut sensitization through the use of CRD. METHODS: 34 patients [n=22 males, 65%; median age eight years, interquartile range (IQR) 5.0-11.0 years] with a reported history of reactions to peanut and/or hazelnut and/or walnut had their serum analyzed for specific IgE (s-IgE) by ImmunoCAP® and ISAC® microarray technique. RESULTS: In children with previous reactions to peanut, the positivity of Arah1 and Arah2 s-IgE was associated with a history of anaphylaxis to such food, while the positivity of Arah8 s-IgE were associated with mild reactions. Regarding hazelnut, the presence of positive Cora9 and, particularly, Cora14 s-IgE was associated with a history of anaphylaxis, while positive Cora1.0401 s-IgE were associated with mild reactions. Concerning walnut, the presence of positive Jug r 1, Jug r 2, Jug r 3 s-IgE was associated with a history of anaphylaxis to such food. ImmmunoCAP® proved to be more useful in retrospectively defining the risk of hazelnut anaphylaxis, because of the possibility of measuring Cor a14 s-IgE. CONCLUSIONS: Our data show that the use of CRD in patients with allergy to peanut, hazelnut and walnut could allow for greater accuracy in retrospectively defining the risk of anaphylactic reaction to such foods.

Study on hydrophilicity and degradability of chitosan/polylactide-co-polycaprolactone nanofibre blend electrospun membrane.

Electrospinning is an interesting technique to produce polymer membranes made of entangled nanofibres. The technique is raising interest in pharmaceutical and biomedical areas. Either electrospun membranes are studied for tissue regeneration purposes, or incorporation of nanoparticles in electrospun membranes can be an opportunity to control the delivery of drug or to obtain dual drug delivery system. In this work suspensions of hydrochloride chitosan salt in copolymer polylactide-co-polycaprolactone (PLA-PCL) solution were electrospun in order to assess an advanced study for developing polymer nanofibre blend membrane loaded with chitosan polymer. The aim of the work was to investigate the properties and stability of chitosan/PLA-PCL electrospun membranes considering their application for tissue regeneration and drug delivery. The electrospun membranes were characterized for their physico-chemical (FT-IR) morphology (SEM) and in vitro biological properties (cytocompatibility and cells engraftment). Results show that homogeneous electrospun PLA-PCL/chitosan blend nanofibres in the range size 800 nm were obtained. Chitosan was loaded inside the nanofibres up to 27.2% (w/w) without modifying nanofibre shape, and only 6% of the loaded chitosan resulted to be on the nanofibre surface. The presence of chitosan in the nanofibres has shown to accelerate the electrospun membranes degradation in vitro.

Multivariate analysis for the optimization of microfluidics-assisted nanoprecipitation method intended for the loading of small hydrophilic drugs into PLGA nanoparticles.

Design of Experiment-assisted evaluation of critical process (total flow rate, TFR, flow rate ratio, FRR) and formulation (polymer concentration and structure, drug:polymer ratio) variables in a novel microfluidics-based device, a staggered herringbone micromixer (SHM), for poly(lactic-co-glycolic acid) copolymer (PLGA) nanoparticles (NPs) manufacturing was performed in order to systematically evaluate and mathematically describe their effects on NPs sizes and drug encapsulation; a small hydrophilic moiety, N-acetylcysteine, was chosen as challenging model drug. SHM-assisted nanoprecipitation method consistently yielded NPs with tailor made sizes (in the range of 100-900 nm) and polydispersity index range from 0.061 to 0.286. Significant effects on NPs sizes were highlighted for TFR and FRR: increasing TFR (from 5 to 15 mL/min) and decreasing FRR (from 1:1 to 1:5 v/v, acetonitrile: buffer) NPs with mean diameter <200 nm were obtained. SHM technique allowed for flexible, application-specific tuning of PLGA NPs size using organic solvents with relatively low toxicity (acetone, acetonitrile), varying aqueous phase composition (Tris buffer vs PVA aqueous solution) and PLGA characteristics (Mw ranging from 25-90 kDa, capped or un-capped PLGA, different lactide:glycolide molar ratio). A very satisfactory N-Ac encapsulation efficiency (more than 67%) and a prolonged release (by 168 h) were achieved.

Internalized chitosan nanoparticles persist for long time in cultured cells.

Chitosan-based nanoparticles (chiNPs) are considered to be potentially good carriers for the sustained intracellular delivery of specific molecules. However, scarce attention has been paid to the long-lasting permanence of these NPs in the intracellular milieu, as well as to their intracellular fate (i.e., distribution, interaction with cell organelles, and degradation) in the long term. In the present study, the presence and subcellular location of FITC-labelled chiNPs were monitored in HeLa cells up to 14 days post-administration using multicolor-fluorescence confocal microscopy and diaminobenzidine photo-oxidation at transmission electron microscopy. The main result of the present study is the demonstration that internalized chiNPs persist inside the cell up to two weeks, occurring in both the cytoplasm and nucleus; accordingly, chiNPs are able to pass from mother to daughter cells through several mitotic cycles. The cells did not show increased mortality or structural damage up to 14 days after chiNP exposure.

Vaccine allergy evaluation and management at the specialized Green Channel Consultation Clinic.

BACKGROUND: Suspected vaccine allergy may be a cause of incomplete or delayed vaccination. Patients at risk of adverse reactions or suspected contraindications need specialized consultation about subsequent vaccinations. OBJECTIVE: To analyse consultancy results for patients at risk of allergic reactions to vaccines as evaluated by the Green Channel University Hospital Immunization Consultancy Clinic. METHODS: A review of cases of allergic reactions to vaccines or contraindications due to underlying diseases or sensitization to vaccine components submitted to the Green Channel was carried out. Analysed data included detailed clinical reaction history, skin and in vitro allergy testing with vaccine components, recommendations for vaccination and outcome of subsequent vaccine administrations. RESULTS: A total of 519 cases, 370 referred for previous local or systemic reactions to vaccines, mostly cutaneous, and 149 sent for suspected contraindications were evaluated. Skin testing was performed on 152 patients, specific IgE determination in 37 subjects and patch testing in 173 cases. After consultation, 442 (85%) subjects were advised to continue vaccination, with personalized precautions (premedication, or alternative brand, or administration in graded doses) for 200 of them. Among the 352 (80%) patients vaccinated as per Green Channel instructions, 33 subjects (9.3%) reported mild allergic or non-specific symptoms and one (0.3%) urticaria with bronchospasm. CONCLUSION AND CLINICAL RELEVANCE: Even though vaccine allergy occurs very rarely, a safe procedure for immunization can be applied, through specialized allergy consultancy, for most subjects with suspected allergy to vaccines, and who could be potentially excluded from vaccination for risk of adverse reactions.

Observational study on HIV-infected subjects failing HAART receiving tenofovir plus didanosine as NRTI backbone.

We evaluated the efficacy of tenofovir (TDF) - and didanosine (ddI)-containing backbones in HIV-infected experienced subjects. We included in the study 245 subjects who started a TDF/ddI-containing HAART with HIV-RNA > 3 log(10) cp/ml and an available genotypic resistance test at baseline. At baseline, median CD4 counts and HIV-RNA were 278 cell/mmc and 4.32 log(10) cp/ml, respectively. Seventy-four subjects (30.2%) discontinued TDF and/or ddI, 23 of them for drug-related toxicities or intolerance. One-hundred and twenty-six (51.4%) subjects achieved virologic success (HIV-RNA < 50 copies/ml in two consecutive determinations) in a median time of 6.1 months; higher HIV-RNA levels (HR: 0.66, 95% CI: 0.54- 0.79, p < 0.001 for each additional log(10) copies/ml), and the total number of mutations either for PI and NNRTI at baseline (HR: 0.87, 95% CI: 0.81-0.92, p < 0.001 for each additional mutation) were both predictors of virologic success. M184V was marginally associated with virologic success (HR: 1.34, 95% CI: 0.94-1.90, p = 0.10 vs no M184V), whilst the number of TAMs was not associated. One-hundred-thirty-three (54.3%) subjects achieved immunologic success (increase of > or = 100 cells/mm(3) from baseline) in a median time of 7.5 months; immunologic success was associated with HIV-RNA levels at baseline (HR: 0.91, 95% CI: 0.79-0.98, p = 0.04 for each additional log(10) copies/ml), the total number of mutations either for PI or NNRTI (HR: 0.91, 95% CI: 0.85-0.98, p = 0.01 for each additional mutation) and CD4 count at baseline (HR: 1.11, 95% CI: 1.00-1.23, p = 0.05 for each additional 100 cells/mm(3)). Results obtained by the on-treatment analyses were comparable. In our study, HAART containing TDF/ddI seem associated with a virologic and immunologic response, when such regimens are chosen according to a genotypic resistance test.

A family outbreak of Escherichia coli O157 haemorrhagic colitis caused by pork meat salami.

A family outbreak of Escherichia coli O157 infection was microbiologically associated with consumption of dry-fermented salami made with pork meat only and produced in a local plant. E. coli O157 strains isolated from a wife and husband, both hospitalized with bloody diarrhoea, and from the salami carried vt1, vt2 and eae genes and shared the same PFGE pattern. The food vehicle implicated in this outbreak is unusual because of both the animal species from which it originates and the fermentation and drying steps of the manufacturing process. This could be the first report of an outbreak associated with a product containing pork meat only. Even though sources of contamination other than pork meat could not be excluded, pork products should not be neglected in E. coli O157 outbreak investigations.

Computing power in case-control association studies through the use of quadratic approximations: application to meta-statistics.

In the framework of case-control studies many different test statistics are available to measure the association of a marker with a given disease. Nevertheless, choosing one particular statistic can lead to very different conclusions. In the absence of a consensus for this choice, a tempting option is to evaluate the power of these different statistics prior to make any decision. We review the available methods dedicated to power computation and assess their respective reliability in treating a wide range of tests on a wide range of alternative models. Considering Monte-Carlo, non-central chi-square and Delta-Method estimates, we evaluate empirical, asymptotic and numerical approaches. Additionally we introduce the use of the Delta-Method, extended to order 2, intended to provide better results than the traditional order-1 Delta-Method. Supplementary data can be found at: http://stat.genopole.cnrs.fr/software/dm2.

A fast, unbiased and exact allelic test for case-control association studies.

Association studies are traditionally performed in the case-control framework. As a first step in the analysis process, comparing allele frequencies using the Pearson's chi-square statistic is often invoked. However such an approach assumes the independence of alleles under the hypothesis of no association, which may not always be the case. Consequently this method introduces a bias that deviates the expected type I error-rate. In this article we first propose an unbiased and exact test as an alternative to the biased allelic test. Available data require to perform thousands of such tests so we focused on its fast execution. Since the biased allelic test is still widely used in the community, we illustrate its pitfalls in the context of genome-wide association studies and particularly in the case of low-level tests. Finally, we compare the unbiased and exact test with the Cochran-Armitage test for trend and show it perfoms similarly in terms of power. The fast, unbiased and exact allelic test code is available in R, C++ and Perl at: http://stat.genopole.cnrs.fr/software/fueatest.

Declining incidence of AIDS and increasing prevalence of AIDS presenters among AIDS patients in Italy.

Presented here are the results of a cohort study conducted on 3,483 consecutive HIV/AIDS patients between January 1993 and December 2000 to determine trends in AIDS incidence and presentation. The incidence of AIDS was calculated in the general population and examined further according to gender, age (< or = or >49 years), and heterosexual behaviour as a risk factor for HIV. Multivariate analysis was used to identify variables associated with AIDS presenters (defined as patients diagnosed with AIDS within 1 month of the first HIV-positive test). The numbers of patients with AIDS classified as (i) AIDS presenters, (ii) known HIV-positive patients on antiretroviral treatment, and (iii) known HIV-positive patients not receiving antiretroviral treatment were calculated. The overall incidence of AIDS decreased over time, mainly due to the lower number of patients on antiretroviral treatment developing AIDS. Factors associated with a higher risk of being an AIDS presenter were male gender and year of HIV diagnosis. Among patients with AIDS, the proportion of AIDS presenters increased from 13.8% prior to 1997 (when protease inhibitors were introduced in Italy) to 32.5% after 1997. Variables predictive of being an AIDS presenter were male gender, age at diagnosis, and AIDS diagnosis in the years 1997-2000. Heterosexuals had a higher risk of being AIDS presenters and a lower risk of being HIV-positive and not receiving antiretroviral treatment than intravenous drug users. In Italy, AIDS occurs mainly in subjects unaware of their HIV status (especially males, the elderly, and those infected heterosexually) or in patients refusing antiretroviral therapy (mainly intravenous drug users who do not refer to specialised centres).

Predictive role of the three-month CD4 cell count in the long-term clinical outcome of the first HAART regimen.

The aim was to evaluate whether the three-month CD4 cell counts are a reliable predictor of the long-term clinical outcome of HAART-treated patients, by an observational study of 585 patients initiating HAART in a clinical setting. Clinical failure was defined as the occurrence of new or recurrent AIDS-defining events or death, and was analysed by means of intention-to-treat, univariate and multivariate analyses. An adjusted Cox regression model was used to evaluate the effect of three-month CD4+ counts on clinical outcome. Clinical failure occurred in 65 patients (11.1%) during a median follow-up of 31 months (1-65) as a result of new AIDS-defining events (ADEs) in 48 patients, ADE recurrence in six, and death in 11. The mean (median; range) CD4+ counts were 156/microL (155; 4--529) in patients with and 362/microL (326; 18--1162) in patients without clinical failure (P < .0001). Moreover, the proportion of patients with mean CD4+ counts < 200 microL was higher in those experiencing subsequent clinical failure (chi2: 41.11; P< .00001). Multivariate analysis showed that baseline CD4+ counts < 50 microL, HIV-RNA > 100,000 copies/mL and AIDS at baseline predicted failure; after adjusting for three-month CD4+ counts, this marker was the only one independently associated with clinical failure (HR 2.93; 95% Cl: 1.16--7.38). The three-month immunologic response is a reliable predictor of long-term clinical outcome.

Forecasting the growth of multicell tumour spheroids: implications for the dynamic growth of solid tumours.

The growth dynamics of multicell tumour spheroids (MTS) were analysed by means of mathematical techniques derived from signal processing theory. Volume vs. time trajectories of individual spheroids were fitted with the Gompertz growth equation and the residuals (i.e. experimental volume determinations minus calculated values by fitting) were analysed by fast fourier transform and power spectrum. Residuals were not randomly distributed around calculated growth trajectories demonstrating that the Gompertz model partially approximates the growth kinetics of three-dimensional tumour cell aggregates. Power spectra decreased with increasing frequency following a 1/f(delta) power-law. Our findings suggest the existence of a source of 'internal' variability driving the time-evolution of MTS growth. Based on these observations, a new stochastic Gompertzian-like mathematical model was developed which allowed us to forecast the growth of MTS. In this model, white noise is additively superimposed to the trend described by the Gompertz growth equation and integrated to mimic the observed intrinsic variability of MTS growth. A correlation was found between the intensity of the added noise and the particular upper limit of volume size reached by each spheroid within two MTS populations obtained with two different cell lines. The dynamic forces generating the growth variability of three-dimensional tumour cell aggregates also determine the fate of spheroid growth with a strong predictive significance. These findings suggest a new approach to measure tumour growth potential.

Outcome of a second-line protease inhibitor-containing regimen in patients failing or intolerant of a first highly active antiretroviral therapy.

The outcome of second-line protease inhibitor (PI)-containing highly active antiretroviral therapy (HAART) was investigated in 263 patients who were failed by (n = 148) or intolerant of (n = 115) a first HAART regimen. The endpoints were virologic failure (decline in HIV RNA < 1 log10 copies/ml after > or = 2 months) and discontinuation due to intolerance/toxicity. During a median follow-up of 483 days (33-1087 days), 154 patients (59%) discontinued the second regimen, 86 (33%) because of intolerance/toxicity; another 135 patients (51.3%) showed virologic failure. Independent factors associated with virologic failure (Cox's model) were 7 to 12 months of first HAART (hazard ratio [HR] 1.70 versus < or = 6 months: 95% confidence interval [CI], 1.08-2.70) and gender (HR 1.58 males versus females: 95% CI, 1.04-2.30); the negatively associated factors were advanced age (HR 0.61 > 34 years versus < or = 34 years: 95% CI, 0.42-0.88), a saquinavir-containing first HAART (HR 0.57 versus indinavir: 95% CI, 0.34-0.93) and change due to intolerance/toxicity (HR 0.58 versus failure: 95% CI, 0.35-0.98). The independent variables predictive of discontinuation due to intolerance/toxicity were the reason for switching (HR 1.79 intolerance versus failure: 95% CI, 1.02-3.16) and the first protease inhibitor (PI) regimen (HR 0.42 ritonavir versus indinavir: 95% CI, 0.22-0.80). Given that patients who are failed by a first regimen are at high risk of having rescue therapy fail as well, second-line regimens including therapies directed by testing of drug resistance patterns of clinical viral isolates are warranted. Patients experiencing toxicity due to a first PI-containing regimen are at risk of toxicity to other PIs and should be addressed to PI-sparing HAART.

Genetic grafting of membrane-acting peptides to the cytotoxin dianthin augments its ability to de-stabilize lipid bilayers and enhances its cytotoxic potential as the component of transferrin-toxin conjugates.

Three chimeric proteins were obtained by fusing together the dianthin gene and DNA fragments encoding for the following membrane-acting peptides: the N-terminus of protein G of the vesicular stomatitis virus (KFT25), the N terminus of the HA2 hemagglutinin of influenza virus (pHA2), and a membrane-acting peptide (pJVE). Chimeric dianthins (KFT25DIA, pHA2DIA and pJVEDIA) retained full enzymatic activity in cell-free assays and showed increased ability to induce pH-dependent calcein release from large unilamellar vesicles (LUVs). pHA2DIA and pJVEDIA also showed faster kinetics of interaction with LUVs, while KFT25DIA and pHA2DIA displayed a reduced cytotoxicity as compared to wild-type dianthin. Conjugates made by chemically cross-linking KFT25DIA or pJVEDIA and human transferrin (Tfn) showed greater cell-killing efficiency than conjugates of Tfn and wild-type dianthin. As a consequence, by fusion of membrane-acting peptides to the dianthin sequence the specificity factor (i.e., the ratio between non-specific and specific toxicity) of Tfn-KFT25DIA, Tfn-pHA2DIA and Tfn-pJVEDIA was increased with respect to that of Tfn-based conjugates made with wild-type dianthin. Taken together, our results suggest that genetic fusion of membrane-acting peptides to enzymatic cytotoxins results in the acquisition of new physico-chemical properties exploitable for designing new recombinant cytotoxins and to tackle cell-intoxication mechanisms.

CD4 cell counts at the third month of HAART may predict clinical failure.

OBJECTIVE: To evaluate the influence of immunological and virological markers on clinical outcome in patients receiving their first highly active antiretroviral therapy (HAART) regimen. DESIGN AND METHODS: Observational study of 585 patients initiating HAART in a clinical setting. Clinical failure was defined as the occurrence of new or recurrent AIDS-defining events or death, and was analysed by means of intention-to-treat, univariate and multivariate analyses. An adjusted Cox regression model was used to evaluate the effect of 3-month CD4 cell counts on clinical outcome. RESULTS: Clinical failure occurred in 55 patients (9.4%) during a median follow-up of 483 days (range 33-1334 days): 45 new AIDS-defining events (ADEs) in 38, ADE recurrence in six, and death in 11. Twenty-four of the 45 new ADEs (53.4%) occurred during the first 3 months of HAART, and 11 of 45 (24.4%) in the presence of CD4 cell counts > 200 x 10(6) cells/l. The mean (median, range) CD4 counts were 144 x 10(6) cells/l (128, 4-529) in patients with and 322 x 10(6) cells/l (288, 14-1162) in patients without clinical failure (P < 0.0001). Moreover, the proportion of patients with mean CD4 cell counts < 200 x 10(6) cells/l was higher in those experiencing subsequent clinical failure (X2 test: 26.75; P < 0.00001). Multivariate analysis showed that baseline CD4 cell counts < 50 x 10(6) cells/l and AIDS at enrolment predicted failure; after adjusting for 3-month CD4 cell counts, this marker was the only one independently associated with clinical failure (hazard risk, 4.79; 95% confidence interval, 1.40-16.47). CONCLUSIONS: The 3-month immunological response is a reliable predictor of long-term clinical outcome.

Oscillating growth patterns of multicellular tumour spheroids.

The growth kinetics of 9L (rat glioblastoma cell line) and U118 (human glioblastoma cell line) multicellular tumour spheroids (MTS) have been investigated by non-linear least square fitting of individual growth curves with the Gompertz growth equation and power spectrum analysis of residuals. Residuals were not randomly distributed around calculated growth trajectories. At least one main frequency was found for all analysed MTS growth curves, demonstrating the existence of time-dependent periodic fluctuations of MTS volume dimensions. Similar periodic oscillations of MTS volume dimensions were also observed for MTS generated using cloned 9L cells. However, we found significant differences in the growth kinetics of MTS obtained with cloned cells if compared to the growth kinetics of MTS obtained with polyclonal cells. Our findings demonstrate that the growth patterns of three-dimensional tumour cell cultures are more complex than has been previously predicted using traditional continuous growth models.

A non-parametric method for the analysis of experimental tumour growth data.

Analysis of tumour growth is required to investigate the biology of tumours and to determine the effects of new anti-tumour therapies. A non-parametric mathematical method for the analysis of a set of experimental tumour growth data is described. The method is based on the similarity between time series of tumour size measurements (e.g. tumour volume), similarity being defined as the Euclidean distance between data measured for each tumour at the same time. Subsets of similar time series are found for a given population of tumours. A biologically meaningful parameter H has been derived which is a measure of the scattering of experimental volume samples. The method has been applied to the analysis of the growth of (i) untreated multicellular tumour spheroids obtained with different cell lines and (ii) spheroids treated with cytotoxic drugs (immunotoxins). Results are compared with those previously obtained by applying the classical Gompertz growth model to the analysis of treated and untreated spheroids.

Clinical outcome and predictive factors of failure of highly active antiretroviral therapy in antiretroviral-experienced patients in advanced stages of HIV-1 infection.

OBJECTIVE: To verify the effectiveness of highly active antiretroviral therapy (HAART) and to identify any factors predictive of clinical outcome in a clinical setting. DESIGN: Observational study. METHODS: Treatment failure (i.e., the occurrence of new or recurrent AIDS-defining events, death or any definitive discontinuation) and the course of CD4+ cell counts and HIV RNA copies were evaluated in 250 heavily pretreated HIV-infected patients starting HAART [153 with indinavir (IDV), 55 with ritonavir (RTV), 43 with saquinavir (SQV)]. Univariate and multivariate analyses were performed to identify predictors of worse outcome. RESULTS: During a median follow-up of 8 months, 75 patients (30%) had treatment failure because of the occurrence of an AIDS-defining event or death (n = 24), inefficacy (n = 24), or severe intolerance (n = 27). Twenty new and six recurrent AIDS-defining events, and nine deaths occurred (six out of 20 AIDS-defining events and two out of nine deaths within 1 month of treatment). CD4+ counts were above 200 x 10(6)/l at AIDS diagnosis in only two patients. None of the SQV patients, 12 (7.8%) of the IDV patients, and 15 (27.3%) of the RTV-treated patients were considered non-compliant. The SQV-containing regimens independently correlated with treatment failure (relative risk, 2.46; 95% confidence interval, 1.20-5.03; versus IDV). Low compliance partially determined outcome in RTV-treated patients; both severe immunodepression and AIDS at baseline were predictive of treatment failure. There was a 10-fold increase in CD4+ cell counts in the patients treated with IDV and RTV; the best virological outcome occurred in IDV-treated patients, with 68.4% of patients showing undetectable HIV RNA copies after 6 months. CONCLUSIONS: HAART was effective in 70% of patients; low compliance and previous AIDS diagnosis represented predictive factors of therapy failure.