A Multi-Variate framework to assess reliability and discrimination power of Bayesian estimation of Intravoxel Incoherent Motion parameters

PURPOSE

To propose a multivariate multi-step framework for a systematic assessment of the estimation reliability and discriminability of Intravoxel Incoherent Motion (IVIM) model parameters.

METHODS

Monte-Carlo simulations were generated on a range of SNRs and in different IVIM combinations considering: i) a dense discretization with 24 b-values; ii) a discretization with 9 b-values. A state-of-the-art Bayesian fitting method was adopted. The framework assessed: i) the best model between mono- and bi-exponential, through the BIC index; ii) the fitting accuracy; iii) the power in discriminating two different IVIM parameters distributions of estimated coefficients, using a multivariate test. Exemplificative oncologic cases were also presented.

RESULTS

The bi-exponential fitting was reliable for perfusion fraction higher than 5%, with high accuracy in D estimation, acceptable error for f, but high uncertainty in D*. The discrimination of two distributions is generally feasible if differences in D values (at least 0.3 x10^-3 mm²/s) are present; in the case of similar D values, a minimal difference of 5% in f can be discriminated just in case of balanced sample size and dense b-values discretization, whereas the impact of D* is quite negligible. These results were also supported by clinical examples.

CONCLUSIONS

IVIM model is generally accurate in estimating diffusion, but uncertainties related to perfusion estimation are not negligible and compromise the discrimination power when different populations should be differentiated. The proposed framework should be adopted as interpretative guidelines to better understand when IVIM model applied on real data can provide reliable findings.

Serum and exhaled breath condensate leptin levels in asthmatic and obesity children: a pilot study

BACKGROUND

Recent studies have highlighted the possible involvement of leptin in inflammation. The leptin receptor is also expressed by alveolar macrophages, T lymphocytes and bronchial epitelial cells, suggesting a possible role in the cascade of airway inflammation.

OBJECTIVES

The aim of the study was to evaluate the levels of leptin in exhaled breath condensate (EBC) from asthmatic, normal- and overweight children, in relationship with airway inflammation.

METHODS

15 asthmatic non-obese children, 15 healthy non-asthmatic non-obese children, 11 obese children with asthma (OA) and 20 obese children without asthma (ONA) were enrolled. Body impedance of body weight, EBC collection, FeNO, spirometry and a blood sampling for serum leptin were assessed.

RESULTS

Leptin EBC levels were significantly higher (3.9 ng ml^-1 ± 1.3) in overweight children than those obese with asthma (3.6 ng ml^-1 ± 1.6; p = 0.97), non-owerweight asthmatics (2.2 ng ml^-1 ± 1.2; p < 0.0001) and in healthy children (0.9 ng ml^-1 ± 0.6; p < 0.001). Leptin EBC levels in asthmatic children were significantly higher than in healthy children (p = 0.05). Leptin serum levels were significantly higher in the overweight children compared with the asthmatics (12.7 ng ml^-1 ± 13.2; p < 0.001) and the healthy group (11.1 ng ml^-1 ± 11.2; p < 0.001). We observed a significant correlation between EBC-leptin levels and the serum-leptin levels (p = 0.001). No correlations were found between EBC-leptin levels, FeNO and lung function.

CONCLUSIONS

This study shows that leptin is measurable in EBC in children and that EBC-leptin levels are significantly higher in the obese subjects and in asthmatic ones compared with healthy subjects. Leptin may therefore represent a non-invasive marker of non-specific airway inflammation in children.

IL-8 and pH Values in Exhaled Condensate after Antibiotics in Cystic Fibrosis Children

Interleukin (IL)-8 is a major factor in inflammatory response and the IL-8 levels in exhaled breath condensate (EBC) may be used as a marker of airway inflammation. Airway acidification is implicated in the pathophysiology of obstructive airway diseases and pH EBC values have been used as a marker of airway acidification. The aim of our study is to investigate whether IL-8 and pH levels in EBC of cystic fibrosis (CF) children with respiratory exacerbations change after antibiotic treatment. Lung function, IL-8 and pH EBC values were measured in fifteen CF children (mean age 11 years) with acute exacerbation before (T0) and after two weeks (T1) of antibiotic treatment. IL-8 and pH values were compared by paired t-test. A p<0.05 was considered significant. IL-8 EBC levels decreased after antibiotic treatment (TO 0.36±0.03pg/ml vs T1 0.28±0.03pg/ml; p=0.03) and pH values increased (TO 7.3610.09 vs T1 7.61±0.08; p=0.04). Results suggest possible application of EBC as a non-invasive tool to monitor efficacy of antibiotic treatment in CF patients.

Markers of oxidative stress are increased in exhaled breath condensates of children with atopic dermatitis

BACKGROUND

Airway inflammation may be present in subjects affected by atopic dermatitis (AD) but still without asthma symptoms. Exhaled breath condensate (EBC) reflects the composition of bronchoalveolar extracellular lining fluid that contains a large number of mediators of airway inflammation and oxidative damage.

OBJECTIVES

  We assessed inflammatory markers in the EBC of patients with AD. Fifty-six children (34 girls and 22 boys) were enrolled: 33 affected by AD and 23 healthy controls.

METHODS

  EBC was collected using a condenser device. We measured EBC pH and concentrations of leukotriene B4 (LTB4), 8-isoprostane, H(2) O(2) , malondialdehyde and 4-hydroxynoneal. Respiratory resistance was also evaluated.

RESULTS

  EBC pH in patients with AD was significantly lower than in healthy children, median (range) being 8·02 (7·94-8·12) in AD vs. 8·11 (8·05-8·16) (P = 0·02). The values of exhaled 8-isoprostane and LTB4 were significantly increased in subjects with AD compared with normal controls (P < 0·01 and P < 0·001, respectively). There was increased 4-hydroxynoneal in patients with AD but this did not reach statistical significance. Evaluating respiratory resistance, no bronchoreversibility was demonstrated in the children with AD.

CONCLUSIONS

pH, LTB4 and 8-isoprostane in EBC could be sensitive markers of airway inflammation in children with AD. Prospective studies would be of interest to evaluate if airway inflammation, not yet clinically evident, could predict the development of asthma later in life in children with AD.

Inhibition of somatosensory evoked potentials during spinal cord stimulation and its possible role in the comprehension of antalgic mechanisms of neurostimulation for neuropathic pain

BACKGROUND

Spinal cord stimulation (SCS) has been widely used for pain relief of patients with neuropathic chronic pain, frequently with only partial efficacy. Further advancements probably need a better understanding of SCS mechanisms, yet largely unknown. Aims of this paper were to answer the question if the lumbar SCS inhibits the tibial nerve somatosensory evoked potentials (SEPs) and to discuss the role of lemniscal afferents modulation in the antalgic mechanism of SCS.

METHODS

Ten consecutive patients successfully treated with implanted SCS devices for chronic pain in the lower limbs (four males, six females, age range 42-72 years) were enrolled. All the patients had an implanted system with an epidural lead connected to a pulse generator. The vertebral level ranged from T9 to T12. The cortical SEPs complex P39-N50-P60 was recorded at the basal (T0) evaluation, during the stimulation (T1) and immediately after the stimulation (T2).

RESULTS

In two of ten patients (20%) the complex P39-N50-P60 became unrelievable at the T1 control (stimulator on). In the remaining eight patients statistical analysis showed a significant reduction of the P39/N50 amplitude at T1 recording. In all patients considered, T0 and T2 recordings were not significantly different, suggesting a fast recovery of the SCS effect on SEPs.

CONCLUSION

The results obtained in the present study show an inhibitory effect of SCS on SEPs and support the hypothesis that in some forms of neuropathic pain the antalgic effect of SCS could be attributed to the collision of action potentials travelling in opposite direction on peripheral large diameter fibres.

Nasal nitric oxide and nitric oxide synthase expression in primary ciliary dyskinesia

No study has evaluated the correlation between different expression of nitric oxide synthase (NOS) isoforms in nasal epithelial cells and nasal NO (nNO) level in primary ciliary dyskinesia (PCD). Gene expression of endothelial (NOS3) and inducible NOS (NOS2) and their correlation with nNO level, ciliary function and morphology were studied in patients with PCD or secondary ciliary dyskinesia (SCD). NOS3 gene polymorphisms were studied in blood leukocytes. A total of 212 subjects were studied (48 with PCD, 161 with SCD and three normal subjects). nNO level correlated with mean ciliary beat frequency (p = 0.044; r = 0.174). The lower the nNO level the higher was the percentage of immotile cilia (p<0.001; r = -0.375). A significant positive correlation between NOS2 gene expression and nNO levels was demonstrated in all children (p = 0.001; r = 0.428), and this correlation was confirmed in patients with PCD (p = 0.019; r = 0.484). NOS2 gene expression was lower in PCD than in SCD (p = 0.04). The NOS3 isoform correlated with missing central microtubules (p = 0.048; r = 0.447). nNO levels were higher in PCD subjects with the NOS3 thymidine 894 mutation, and this was associated with a higher ciliary beat frequency (p = 0.045). These results demonstrate a relationship between nNO level, NOS mRNA expression and ciliary beat frequency.

Nasal nitric oxide levels in healthy pre-school children

The evaluation of nasal nitric oxide (nNO) has been proposed as a screening tool in children with clinically suspectable primary ciliary dyskinesia. Nevertheless, normal values have been reported for school-aged children. This study was designed to identify normal nNO levels in pre-school children. nNO was assessed in 300 healthy children aged between 1.5 and 7.2. Two hundred and fifty of them were unable to fulfill the guideline requirements for nNO measurement and were assessed by sampling the nasal air continuously with a constant trans-nasal aspiration flow for 30 s during tidal breathing. For those children who were able to cooperate, the average nNO concentration was calculated according to guidelines. A statistically significant relationship between nNO level and age was demonstrated in this study group of pre-school children (p < 0.001). An increase in nNO of about 100 ppb was observed in children older than 6 yr vs. those aged < 3. This study presents a description of normal nNO values in pre-school children. The effect of the age and the eventual presence of rhinitis and snoring need to be considered whenever nNO is evaluated in the clinical practice, in particular in non-cooperative children.

Exhaled nitric oxide levels in childhood asthma: a more reliable indicator of asthma severity than lung function measurement?

The level of exhaled nitric oxide (NO) has been demonstrated to reflect the degree of airway inflammation in patients with asthma and to be related to the severity of asthma, as well as to the efficacy of treatment. In contrast, lung function tests provide information about airway volumes and flows reflecting the level of airway obstruction, but do not allow any direct information about the degree of airway inflammation. Several studies have evaluated the relationships between the level of airway inflammation assessed by exhaled NO and the levels of airway obstruction and/or bronchial hyperresponsiveness in asthmatic adults and children. These studies highlight the complex pathophysiology of asthma and suggest that exhaled NO may have a promising role in addition to lung function measurement in the evaluation of asthma severity in children.

Childhood Asthma Control Test and airway inflammation evaluation in asthmatic children

BACKGROUND

The Childhood Asthma Control Test (C-ACT) has been proposed as a tool in assessing the level of disease control in asthmatic children. To evaluate the position of C-ACT in the clinical management of asthmatic children, in relationship to the level of airway inflammation as assessed by fractional exhaled nitric oxide (FeNO) and with lung function.

METHODS

A total of 200 asthmatic children were included in the study: 47 children with newly diagnosed asthma ('New') and without any regular controller therapy; and 153 children with previously diagnosed asthma, treated according to GINA guidelines, and evaluated during a scheduled follow-up visit ('Follow-up'). Childhood Asthma Control Test, FeNO and lung function [forced expiratory volume 1 (FEV1) and forced vital capacity (FVC)] were evaluated.

RESULTS

In New vs Follow-up participants, C-ACT score (P < 0.001), FVC (P < 0.005) and FEV1 (P < 0.05) were significantly lower, and FeNO (P = 0.011) were significantly higher. In New, but not in Follow-up participants, significant correlations were observed between C-ACT score and FeNO (r = -0.51; P < 0.001), FEV1 (r = 0.34; P = 0.022) and FEV1/FVC (r = 0.32; P = 0.03). This lack of correlation in Follow-up visits seemed attributable to dissociation between inadequately controlled asthma by C-ACT ratings with normalization of other measures such as FeNO levels.

CONCLUSIONS

This study confirms and expands the concept that C-ACT is complementary to, but not a substitute for, other markers of disease control in asthmatic children, especially in the context of follow-up visits.

Bioimpedance monitoring of airway inflammation in asthmatic allergic children

BACKGROUND

Asthma in childhood is characterized by chronic inflammation. Measurement of bioimpedance (BI) is a non-invasive way of detecting airway inflammation. The aim was to compare BI with exhaled nitric oxide (eNO) and lung function evaluations in asthmatic allergic children while not exposed to offending allergens.

METHODS

22 asthmatic children allergic to house dust mites have been enrolled while residents at high altitude in an environment free of house dust mites. They were evaluated at T0 after allergen exposure at home, at T1 and at T2 after 1 and 4 months of allergen avoidance, respectively.

RESULTS

eNO decreased from 32.21 +/- 5.70 ppb at T0 to 21.92 +/- 4.36 ppb at T1, after one month at high altitude (p = 0.038), without a further decrease at T2. Data in electrical activity showed a significant decrease in conductivity of lower airways between T0 (48.53 +/- 3.53 microA) and T1 (42.08 +/- 3.47 microA) (p = 0.023). deltaB parameter (difference between conductivity of lower respiratory tract and average yield) showed significant decrease from T0 (20.75 +/- 2.64 microA), and T1 (12.84 +/- 2.52 microA) (p < 0.01), but no further decrease at T2. No difference in lung function parameters was observed.

CONCLUSION

Allergen avoidance regimen modifies inflammatory parameters in allergic asthmatics. Evaluation of extracellular bioelectrical conductivity seems to represent a promising non-invasive method to assess airway inflammation.

Quantitative versus qualitative modeling: a complementary approach in ecosystem study

Natural disturbance or human perturbation act upon ecosystems by changing some dynamical parameters of one or more species. Foreseeing these modifications is necessary before embarking on an intervention: predictions may help to assess management options and define hypothesis for interventions. Models become valuable tools for studying and making predictions only when they capture types of interactions and their magnitude. Quantitative models are more precise and specific about a system, but require a large effort in model construction. Because of this very often ecological systems remain only partially specified and one possible approach to their description and analysis comes from qualitative modelling. Qualitative models yield predictions as directions of change in species abundance but in complex systems these predictions are often ambiguous, being the result of opposite actions exerted on the same species by way of multiple pathways of interactions. Again, to avoid such ambiguities one needs to know the intensity of all links in the system. One way to make link magnitude explicit in a way that can be used in qualitative analysis is described in this paper and takes advantage of another type of ecosystem representation: ecological flow networks. These flow diagrams contain the structure, the relative position and the connections between the components of a system, and the quantity of matter flowing along every connection. In this paper it is shown how these ecological flow networks can be used to produce a quantitative model similar to the qualitative counterpart. Analyzed through the apparatus of loop analysis this quantitative model yields predictions that are by no means ambiguous, solving in an elegant way the basic problem of qualitative analysis. The approach adopted in this work is still preliminary and we must be careful in its application.

Azithromycin may reduce cholestasis in primary sclerosing cholangitis: a case report and serendipitous observation

The newer macrolides have been shown to exert additional anti-inflammatory effects. We report the possible effect of azithromycin on primary sclerosing cholangitis in a patient treated with the drug for severe asthma. A 45-year-old woman with Crohn?s disease and primary sclerosing cholangitis, also suffering from severe asthma, was treated with azithromycin 500 mg OD for 3 consecutive days a week because of the clinical suspicion of bronchiectasis and the severity of her asthma. When the therapy was discontinued, her urine again became darker, pruritus reappeared with the usual severity and laboratory parameters, evaluated after 6 weeks without azithromycin, also worsened. For these reasons macrolide treatment was re-established. Cholestasis-related symptoms and the dark colour of the urine were again reduced 6 weeks later and laboratory parameters were again reversed. We are therefore tempted to speculate that azithromycin may have an effect on primary sclerosing cholangitis on the basis of its anti-inflammatory properties.

Prevalence and risk factors for atopic dermatitis in preschool children

BACKGROUND

Atopic dermatitis (AD) is a common condition in infancy which usually disappears by 3 years of age in a significant proportion of children. The prognosis is mostly determined by severity and presence of atopic sensitization.

OBJECTIVES

To investigate prevalence of AD, comorbidities and risk factors in a population of preschool children aged 3-5 years.

METHODS

Children in kindergartens were evaluated. The International Study of Asthma and Allergies in Childhood written questionnaire (WQ) was used, with additional questions on risk factors. Atopy was investigated by skin prick tests.

RESULTS

One thousand, four hundred and two valid WQs (92% response rate) were returned for evaluation. The prevalence of AD symptoms in the last 12 months in the whole population was 18.1% (254 cases). Seventy-two per cent of these children presented AD-specific localizations. The prevalence of eczema as a doctor's diagnosis in the total population was 15.4%. Positive atopic sensitization was present in 18.6% of the total and in 32.2% of the AD study population, respectively. Multiple sensitivities were observed in 58.2% of sensitized children. The prevalence of sensitization demonstrated that the most common sensitizing allergens in children with AD were mites and grass pollen. Rhinitis symptoms and wheezing were present in 32.2% and 24.2%, respectively, of children with AD. Allergic sensitization to egg, cat, grass pollen and mites, as well as the presence of symptoms of rhinitis, and a positive family history of atopy were all significant risk factors for AD.

CONCLUSIONS

The study demonstrates a high prevalence of AD and a close relationship with rhinitis symptoms. Significant risk factors for AD were sensitization to food or inhalant allergens as well as parental history of atopy.

Exhaled air temperature in asthma: methods and relationship with markers of disease

BACKGROUND

Exhaled breath temperature has been proposed as a surrogate marker for the evaluation of airway inflammation in asthmatic patients.

OBJECTIVE

The aim of the present study was to extend the investigation of exhaled air temperature as a means for the evaluation of airway inflammation using a professionally developed instrument.

METHODS

Fifty-seven children, 41 allergic mild asthmatics and 16 healthy controls have been evaluated. They underwent exhaled air temperature and lung function measurement. The asthmatic children also underwent exhaled nitric oxide measurement, and hypertonic saline sputum induction for the evaluation of eosinophil (EOS) percentage.

RESULTS

The level of exhaled temperature was significantly higher in asthmatics than in controls, being 30.18+/-0.14 degrees C vs. 27.47+/-0.24 degrees C (P<0.001). In asthmatic children, a positive relationship was observed between exhaled air temperature and both exhaled nitric oxide (r=0.39; P=0.01) and EOS percentage in samples from induced sputum (rho=0.53; P=0.04).

CONCLUSION

The data from the present study support the hypotheses that exhaled breath temperature is related to the degree of airway inflammation in asthma.

Flunisolide decreases exhaled nitric oxide and nitrotyrosine levels in asthmatic children

BACKGROUND

Exhaled nitric oxide (FeNO) has been reported to be elevated in the oxidative stress involved in asthmatic patients, and the reaction of nitric oxide (NO) with superoxide anions results in the formation of nitrotyrosine. The purpose of this study was to investigate the effect of inhaled steroid treatment on nitrotyrosine levels collected by exhaled breath condensate (EBC) and on FeNO.

METHODS

This was a single-blind placebo-controlled study. The lung function, FeNO, and nitrotyrosine levels were evaluated in 10 asthmatic children.

RESULTS

The nitrotyrosine levels were stable during the placebo period (T0 = 1.16 ng/ml versus T1 = 1.05 ng/ml; NS.), whereas they decreased after the treatment with flunisolide (T2 = 1.14 ng/ml versus T3 = 0.88 ng/ml; P < .001). No significant reduction in FeNO levels was observed after placebo treatment (T0 = 38.4 ppb versus T1 = 34.7 ppb, NS.). In contrast, FeNO values decreased significantly being at T3 = 14.9 ppb (T1 versus T3; P = .024).

CONCLUSIONS

This study shows that corticosteroid treatment reduces nitrotyrosine levels in EBC of asthmatic subjects.

Effect of budesonide and montelukast in asthmatic children exposed to relevant allergens

BACKGROUND

Montelukast has been shown to be effective in controlling the increase in exhaled NO in asthmatic children re-exposed to house dust mite (HDM). This study compared the effect of low dose inhaled budesonide and oral montelukast in preventing the expected relapse of airway inflammation and reactivity in a group of 24 mild asthmatic children allergic to HDM after a brief period of exposure to relevant allergens.

METHODS

Lung function, bronchial hyperresponsiveness (BHR) to methacholine (PC(20)), fractional exhaled nitric oxide (FeNO) levels and sputum eosinophilia were evaluated.

RESULTS

Pulmonary function remained stable. The BHR was unchanged after exposure in the group treated with budesonide, whereas a significant increase (P = 0.028) was observed in the patients receiving montelukast. No significant difference was observed in FeNO levels after exposure to mite antigen in the two groups. In both the groups of asthmatic children we observed a significant increase in sputum eosinophil % after the exposure to mite antigen.

CONCLUSIONS

The significant increase in BHR level observed in the group of children receiving montelukast suggests a more comprehensive effect as disease controller by inhaled steroids than by leukotriene antagonist in allergic asthmatic children re-exposed to relevant allergens.

Efficacy in allergen control and air permeability of different materials used for bed encasement

BACKGROUND

Different types of textile are used for the preparation of covers for bed encasement. The aim of the present study was to evaluate different fabrics employed for mattress covers regarding their efficacy in blocking Der p 1 and Fel d 1 as well as their air permeability.

METHODS

Eleven different commercially available fabrics manufactured for allergen avoidance have been tested and compared with regular cotton. Dust samples titered for Der p 1 and Fel d 1 were pulled through the different fabrics using a modified Fussnecker dust trap and collected by a filter located downstream. Airflow through the dust trap was controlled by a vacuum pump operating for 5 min and measured at the beginning (T0) and at the end (T1) of the test.

RESULTS

All the tightly woven and laminated materials were able to control mite allergen permeability allowing air passage but they significantly differed in Fel d 1 permeability. Laminated tissues and laminated tissue not tissued were effective in controlling both the allergens but they did not allow air permeability.

CONCLUSIONS

Detailed knowledge about the actual properties of the products for bed encasement needs to be considered in order to optimize allergen avoidance, disease control and sleep comfort.

Exhaled breath condensate eicosanoids and sputum eosinophils in asthmatic children: a pilot study

Cysteinyl leukotrienes (cys-LTs), LTB4 and 8-isoprostane are increased in the exhaled breath condensate (EBC) from asthmatic patients. The aim of this study was to investigate whether the measurement of cys-LTs, LTB4 and 8-isoprostane in EBC can reflect the level of airway inflammation assessed by induced sputum in asthmatic children sensitized to house dust mite (HDM) during natural avoidance of HDM allergens. Twelve children were evaluated at the time of admission (T0) and after 3 months of stay (T1) at the Istituto Pio XII (Misurina, Italian Dolomites 1756 m). Sputum eosinophil percentage and measurement of cys-LTs, LTB4 and 8-isoprostanes in the breath condensate at T0 and T1 were evaluated. Eosinophil percentage in induced sputum was 8.5 +/- 1.1% at T0 and 3.5 +/- 0.4% at T1 (p = 0.011). Neutrophil percentage in sputum was 1.1 +/- 0.5% at T0 and 1.5 +/- 1.0% at T1 (ns). Cys-LTs mean level was 14.24 +/- 4.53 pg/ml at T0 and 4.65 +/- 0.68 pg/ml at T1 (p = 0.0125). LTB4 level was 2.36 +/- 0.19 pg/ml at T0 and 2.41 +/- 0.23 pg/ml at T1 (ns). 8-Isoprostane level reduced from 17.47 +/- 3.18 pg/ml at T0 to 7.36 +/- 3.26 pg/ml at T1 (p = 0.003). This study show that exhaled cys-LTs and 8-isoprostane, as well as eosinophil percentage in induced sputum, are reduced after allergen avoidance in asthmatic children suggesting a potential application of EBC for the non-invasive evaluation of airway inflammation in asthma in allergic asthmatic children.

Cysteinyl leukotrienes and 8-isoprostane in exhaled breath condensate of children with asthma exacerbations

BACKGROUND

Cysteinyl leukotrienes (Cys-LTs) and isoprostanes are inflammatory metabolites derived from arachidonic acid whose levels are increased in the airways of asthmatic patients. Isoprostanes are relatively stable and specific for lipid peroxidation, which makes them potentially reliable biomarkers for oxidative stress. A study was undertaken to evaluate the effect of a course of oral steroids on Cys-LT and 8-isoprostane levels in exhaled breath condensate of children with an asthma exacerbation.

METHODS

Exhaled breath condensate was collected and fractional exhaled nitric oxide (FE(NO)) and spirometric parameters were measured before and after a 5 day course of oral prednisone (1 mg/kg/day) in 15 asthmatic children with an asthma exacerbation. Cys-LT and 8-isoprostane concentrations were measured using an enzyme immunoassay. FE(NO) was measured using a chemiluminescence analyser. Exhaled breath condensate was also collected from 10 healthy children.

RESULTS

Before prednisone treatment both Cys-LT and 8-isoprostane concentrations were higher in asthmatic subjects (Cys-LTs, 12.7 pg/ml (IQR 5.4-15.6); 8-isoprostane, 12.0 pg/ml (9.4-29.5)) than in healthy children (Cys-LTs, 4.3 pg/ml (2.0-5.7), p=0.002; 8-isoprostane, 2.6 pg/ml (2.1-3.0), p<0.001). After prednisone treatment there was a significant decrease in both Cys-LT (5.2 pg/ml (3.9-8.8), p=0.005) and 8-isoprostane (8.4 pg/ml (5.4-11.6), p=0.04) concentrations, but 8-isoprostane levels remained higher than in controls (p<0.001). FE(NO) levels, which fell significantly after prednisone treatment (p<0.001), did not correlate significantly with either Cys-LT or 8-isoprostane concentrations.

CONCLUSION

After a 5 day course of oral prednisone there is a reduction in Cys-LT and 8-isoprostane levels in EBC of children with an asthma exacerbation, although 8-isoprostane levels remain higher than in controls. This finding suggests that corticosteroids may not be fully effective in reducing oxidative stress in children with an exacerbation of asthma.

Reduction in exhaled nitric oxide immediately after methacholine challenge in asthmatic children

BACKGROUND

The measurement of exhaled nitric oxide (NO) has recently been proposed as a useful technique for the evaluation of airway inflammation in asthma. The purpose of this study was to determine the effect of methacholine bronchial provocation on the levels of exhaled NO in asthmatic children.

METHOD

Exhaled NO was measurement immediately before and after methacholine provocation in 51 children with mild to moderate asthma.

RESULTS

A significant decrease occurred in the level of exhaled NO (p<0.0001) after methacholine bronchial provocation which was not correlated with the percentage fall in forced expiratory volume in 1 second (FEV(1)).

CONCLUSIONS

The methacholine test should not be used immediately before measurement of exhaled NO in children with asthma.

Relationship between exhaled air temperature and exhaled nitric oxide in childhood asthma

Airway inflammation is a characteristic of asthma. Exhaled nitric oxide (eNO) has been demonstrated to be related to actual levels of airway inflammation in asthmatic patients. The purpose of this study was to investigate whether the temperature of exhaled air is related to eNO levels. Temperature of exhaled air and eNO were measured in 52 asthmatic children with a cross-sectional design. A significant relationship was demonstrated between eNO and temperature of peak and plateau exhaled air temperature. The relationship between both the peak and the plateau values and eNO was more evident when it was corrected for environmental temperature. These results suggest a relationship between exhaled nitric oxide and the temperature of exhaled air in asthmatic patients not treated with systemic steroids.

Mite avoidance can reduce air trapping and airway inflammation in allergic asthmatic children

BACKGROUND

We investigated the effects of prolonged allergen avoidance in 18 house dust mite-sensitized asthmatic children during a prolonged residential period at a high altitude, allergen-free environment.

METHODS

Evaluations of residual volume (RV) and exhaled nitric oxide (eNO) were performed (i) at admission to the residential house in September, (ii) in December after 3 months of stay, (iii) in January after 15 days at home, exposed to allergens, and (iv) in June after 9 months of stay.

RESULTS

During the study period RV showed a significant decrease in December (from 117.5 +/- 7.7% to 96.5 +/- 3.2%) (P < 0.02) and a following increase in January (126.2 +/- 17.2%), after allergen re-exposure (P < 0.03). RV decreased again in June at the end of the study period (91.1 +/- 6.0%) (P = 0.001). FEV(1), FEF(25-75) and VC values did not present significant variations. ENO showed a significant decrease in December after 3 months at high altitude (from 21.3 +/- 3.9 p.p.b. to 11.9 +/- 1.7 p.p.b.) (P = 0.03), but no further significant change. No correlation was found between lung volumes and eNO, probably reflecting different aspects of asthma.

CONCLUSIONS

Results suggest that RV may be more sensitive than other respiratory function parameters in identifying children with air trapping, being influenced significantly as the inflammatory indices by effective allergen avoidance/exposure regimen.

Environmental quality and sustainability in the province of Reggio Emilia (Italy): using multi-criteria analysis to assess and compare municipal performance

Sustainability has become an increasingly significant issue, although practical implementation remains difficult. In Italy, promoting sustainability is particularly problematic at the provincial and municipal level, where the lack of resources and expertise, and the effects of uncoordinated policies make it difficult to achieve minimum requirements to make sustainable policies operational. One essential requirement is knowledge of baseline environmental conditions in each municipality. In the province of Reggio Emilia (Northern Italy) Legambiente, an environmental association, launched an initiative called 'Ecopaese' aimed at gathering data on environmental conditions and stimulating local administrations to implement sustainable policies. To this end, the state of the environment in the 45 municipalities within the province has been monitored using 25 indicators. Their values have been used to rank the municipalities by multiple criteria analysis (MCA). The results of this comparative approach provide information about the level of sustainability attained in the province as a whole as well as in the single municipalities. It is hoped that it will provide the basis for direct action plans at the provincial level by identifying areas for remedial action, as recommended by Agenda 21, the declaration adopted by many countries attending the Rio Summit in 1992.

Snail anaphylaxis during house dust mite immunotherapy

This study reports a 12-year-old girl who developed an anaphylactic reaction following snail ingestion during house dust mite (HDM) immunotherapy treatment. Radioallergosorbent (RAST) inhibition showed cross-reactivity between the two allergens, leading to consideration of HDM as the sensitizing agent. Children undergoing HDM immunotherapy treatment should be aware of the potential risks of hypersensitivity reactions to invertebrate foods.

A Multimethodological Approach for the Sustainable Management of Perifluvial Wetlands of the Po River (Italy)

/ Marginal aquatic systems (wetlands) of the Po River (Italy) have become the target of a renewed interest because of their value for recreation, natural reserves, and deposits of sand. To preserve these sites, wise management must be the objective of local administrations. In this paper a strategy for the sustainable use of 11 wetlands is presented. It uses simple economic analysis and multiple criteria techniques and provides suggestions to promote sustainability in terms of conservation of natural resources, economic self-sufficiency, and minimization of potential conflicts about the use of the wetlands. In the understanding that sustainability is framed in a long-term perspective, stability analysis is also considered and performed by means of loop analysis, a qualitative technique. Conditions for stability are then discussed about management opportunities.

[Visual reaction times in a group of patients with single cerebrovascular lesions in rehabilitation]

Approximately fifty percent of stroke survivors have neurological deficits. The evaluation of reaction times permits a study of psychomotor performance, which could be very important for a good rehabilitation outcome.

AIM

The aim of the study was the evaluation of visual reaction times in a group of patients with cerebrovascular lesions, during inpatient hospitalisation in a rehabilitation centre.

MATERIALS AND METHODS

46 right-handed patients (34M, 12F) with unilateral cerebrovascular lesion, confirmed by CT or MRI, were enrolled in the study. In each patients visual Simple Reaction Times (SRT) and Multiple Choice Reaction Times (MCRT) were studied. The patients were asked to react by using the hand ipsilateral to the side of the cerebral lesion. Functional impairment of walking, upper limb and hand were measured by a tailored clinical scale with score ranging from 1 to 12. Depression was measured by a modified version of Hamilton scale, tailored for this kind of patient.

RESULTS

13 of 46 patients (28.2%) showed a pathologic reaction time. There was a lack of correlation between reaction times and age, aphasia, lesion size, time from stroke, functional impairment. Patients with hemorrhagic lesions had significantly lower SRT and MCRT. The subgroup of patients with pathologic reaction times were significantly more depressed than patients with normal reaction times.

CONCLUSION

Judging from the present set of results: a) patients with hemorrhagic lesions have lower reaction times; b) the prolongation of reaction times and post-stroke depression appear to be related in stroke patients. This relationship seems to suggest that post stroke depression can negatively affect functional recovery also by means of an impairment of psychomotor performance.

Exhaled nitric oxide is reduced after sputum induction in asthmatic children

Exhaled nitric oxide (ENO) and eosinophil sputum markers are considered noninvasive markers of airway inflammation in asthma. The aim of this study was to evaluate whether the procedure of sputum induction can affect the level of ENO. We measured ENO before and after sputum induction by inhalation of hypertonic saline solution in 22 asthmatic children and 9 healthy controls. The ENO mean (+/- S. E.M.) value in the group of asthmatic children was reduced from a baseline value of 20.8 (+/- 3.0) ppb to 17.4 (+/- 2.4) ppb after sputum induction (P = 0.0012). In the healthy controls, the mean baseline value of ENO was 9.1 (+/- 2.1) ppb and it was reduced to 4. 8 (+/- 1.1) ppb after induction of sputum (P < 0.01). We suggest that measurements of ENO should be performed after the induction of sputum in asthmatic patients whenever both tests are done in sequence.

Exhaled nitric oxide, serum ECP and airway responsiveness in mild asthmatic children

The purpose of the present study was to assess the possible relationships between exhaled nitric oxide (ENO), a circulating marker of eosinophil activation, serum eosinophil cationic protein (SECP), level of airway responsiveness to methacholine and lung function in asthmatic children, as well as to compare these markers between children with and without inhaled steroid therapy. In a cross-sectional study ENO, SECP and bronchial hyperresponsiveness to methacholine were evaluated in a group of 57 asthmatic children (21 without and 36 with regulator inhaled steroid therapy; aged 6-13 yrs). ENO was significantly lower in steroid treated children (p<0.01). No significant differences between steroid treated and untreated children were observed for the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1; PC20), SECP and FEV1. In the whole study population significant increase correlations were observed between PC20 and SECP (r=-0.329, p=0.013) and between ENO and FEV1% of predicted (r=-0.348, p<0.01). In the group not receiving inhaled steroids the inverse relationship between PC20 and SECP was more evident (r=-0.581, p<0.001). In the steroid-treated group a significant inverse relationship was observed between ENO and FEV1 (r=-0.426, p=0.0011). The level of exhaled nitric oxide and the relationships between lung function, bronchial reactivity and markers of inflammation are different between steroid-treated and untreated asthmatic children. This has implications for the monitoring of asthma in childhood.

Exhaled nitric oxide in asthmatic children exposed to relevant allergens: effect of flunisolide

Inhaled corticosteroids are capable of reducing the level of exhaled nitric oxide (expiratory nitric oxide fraction (FE,NO)) in asthmatic patients in a dose-dependent fashion. The aim of this study was to evaluate whether or not treatment with an inhaled steroid can prevent changes in FE,NO after the exposure to relevant allergens, following avoidance, in asthmatic children allergic to house dust mite. Thirty-two house dust mite-allergy asthmatic children were randomly allocated to treatment with inhaled flunisolide (500 microg b.i.d) or placebo and evaluated before and 2 weeks after a period of natural exposure to mite antigens. Lung function and FE,NO were evaluated. FE,NO was increased in the placebo-treated group after antigen exposure. Treatment with inhaled flunisolide prevented such increase in FE,NO (p<0.001). No change was observed in lung function parameters. Inhaled flunisolide is effective in preventing the increase in airway inflammation observed in allergic asthmatic children re-exposed to allergens.

High level antibody response to retrovirus-associated but not to melanocyte lineage-specific antigens in mice protected against B16 melanoma

Mice vaccinated with Mycobacterium tuberculosis Ag38 gene-transduced B16 melanoma cells showed significant protection from intravenous challenge with parental B16 melanoma cells. No cytotoxic T-cell activity was found against melanoma cells, although the endogenous presence of the mycobacterial gene induced a preferential Th1 response. After immunization, a low serological response against melanoma cells was detected, while a high titer of antibodies directed to parental B16 cells, mainly of IgG2(a) isotype, was found in protected mice after challenge. These antibodies exhibited complement-dependent cytotoxicity against melanoma cells in vitro, while in vivo, used in passive immunization, they induced a decrease in a number of experimental B16 lung metastases. Most of the antibodies were directed against endogenous murine leukemia viruses. No reactivity against melanocyte lineage-specific antigens was observed. In particular, no reactivity was found in sera from protected mice against tyrosinase-related protein 2 (TRP-2), either stably expressed in a non-melanoma cell line or obtained by in vitro transcription-translation, or against tyrosinase, TRP-1 and gp100 antigens immunoprecipitated from B16 cells. Thus, in the B16 murine model, the presence of dominant viral antigens induces a very strong humoral response that might be protective and may inhibit or mask the presence of minor clonotypes.

Exhaled nitric oxide and sputum eosinophil markers of inflammation in asthmatic children

Exhaled nitric oxide and eosinophil sputum markers are considered noninvasive ways in which to evaluate airway inflammation in asthma. The aim of this study was to evaluate the relationships between these methods of evaluation in asthmatic children. In a cross-sectional study of 25 mild-moderate asthmatic children (aged 6-13 yrs, 10 patients on inhaled steroids) exhaled NO was measured along with induced sputum by inhalation of hypertonic saline solution. The sputum was processed for eosinophil count and eosinophil cationic protein (ECP) determination. Serum ECP and lung function (forced expiratory volume in one second (FEV1)) were also measured. A significant correlation was observed between exhaled NO and sputum eosinophils (r = 0.438, p = 0.032) as well as between sputum eosinophils and sputum ECP (r = 0.532, p<0.01). No correlation was observed among exhaled NO and serum ECP, sputum ECP, FEV1, respectively. Furthermore no correlation was observed between sputum eosinophil (%) and serum ECP and between sputum eosinophils and FEV1. There was no correlation among the investigated parameters in children treated with inhaled steroids. In conclusion, exhaled NO and sputum eosinophil counts are concordant in evaluating the degree of airway inflammation in patients with mild-to-moderate asthma. However, the association between these two noninvasive markers becomes less in steroid treated patients.

Environmental allergens and childhood asthma

Exposure to allergens has been shown to lead to sensitization and to the subsequent development of airway hyperresponsiveness in genetically predisposed individuals. Increasing interest is being devoted to mechanisms for the prevention of allergen sensitization and asthma development. Primary prevention (avoiding the sensitization to allergens) requires a large effort as the majority of atopic sensitizations occur in children with no demonstrable risk at the birth. Secondary prevention (deterrence of disease expression despite prior IgE sensitization) requires methods for detecting the population at risk by means of large population screening. Tertiary prevention (minimizing the morbidity for those who already have the disease) may be achieved by allergen avoidance, which has been demonstrated to effectively decrease inflammation in symptomatic patients.

Influence of environmental concentrations of NO on the exhaled NO test

Measurement of levels of exhaled nitric oxide (NO) has been proposed as a noninvasive method for evaluating the degree of airway inflammation in asthmatic patients. Some concern in the interpretation of results of such measurement may arise from possible interference by high environmental concentrations of NO inhaled by these patients. The aim of this study was to verify whether environmental concentrations of NO in the range from 0 to 150 ppb can influence levels of exhaled NO. We tested two groups of subjects. The first group, consisting of 16 subjects, was tested when environmental levels of NO were from 0 to 3 ppb and from 20 to 60 ppb, and exhaled NO mean ppb (+/- SEM) levels were 9.81 +/- 1.43 and 9.78 +/- 1.47 (p = ns) (mean +/- SEM), respectively. The second group, consisting of 30 subjects, was tested at ambient NO concentrations of 0 to 3 ppm, 80 to 100 ppm, and 120 to 150 ppb, and for 18 of these subjects who underwent testing under all three conditions investigated, the mean levels of exhaled NO were 9.23 +/- 1.51, 7.78 +/- 1.19, and 9.33 +/- 1.55 ppb (p = ns), respectively. The results of this study suggest that significantly different ambient levels of NO have no effect on levels of exhaled NO.

Central motor conduction after magnetic stimulation in diabetes

Central motor conduction times (CMCTs), obtained by means of magnetic stimulation of the motor cortex and spinal roots, were studied in 138 patients affected by diabetes mellitus but with no signs or symptoms of central nervous system (CNS) involvement. CMCTs were significantly increased in diabetic patients (p < 0.001, t-test) with respect to normal controls, with values exceeding upper confidence limits (mean +/- 2.5 SD of controls) in about 30% of patients. There was no correlation between CMCT delay and type of diabetes (insulin-dependent or non-insulin-dependent), patient age, disease duration, degree of metabolic control compensation, presence or absence of retinopathy or nephropathy, and presence or absence of peripheral or autonomic neuropathy. CNS involvement in diabetes mellitus is discussed. Particular emphasis is given to the sensitivity and reliability of CMCTs obtained by means of magnetic stimulation as a tool in the early diagnosis of CNS functional alterations in diabetes mellitus.

What is the role of predation on stability of natural communities? A theoretical investigation

A basic question in ecology concerns the role of species interaction on dynamics of natural communities. In this framework, ecologists have considered predation, competition, mutualism, the three most important interactions, highlighting their specific effects on distribution and abundance of species, providing knowledge about phenomena like coexistence and extinction. This paper seeks to identify the effects of predation on stability of natural communities by mathematical models. Simple multispecies community models, organized in trophic levels, are analyzed by means of a qualitative technique, loop analysis, combined with a computer calculation procedure. Results do not support the hypothesis of predation as a stabilizing factor. Rather, the outcomes of the analysis suggest that predation may or may not stabilize a community. This depends on the predator's behaviour and on the network of the community.

The qualitative approach in investigating the role of species interactions on stability of natural communities

Community models with competition and mutualism are qualitatively analyzed using the methodology of loop analysis combined with computer stochastic simulation. The concept of "moving equilibrium" in the growth rate of the species is discussed in 14 "tables of predictions", presented as analytical tools that can help to shed light on controversial ecological issues such as direct versus indirect interaction and positive feedback effects on stability. While the stochastic simulation shows that only little or no difference exists in probability of stability between models with competition and models with mutualism, the related tables of predictions show that the networks among links are able to activate indirect interactions, with both negative and positive effects, between any pair of species. This phenomenon makes it difficult to determine how much stability is related to the direct interactions.