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Biomedical subjects

F Zacchello

Publications and source records attributed to F Zacchello.

At least 19 recordsLinked to original sources
PubMed1999

Reference values of exhaled nitric oxide for healthy children 6-15 years old.

Nitric oxide (NO) can be detected in human exhaled air, and its endogenous production is increased in patients with asthma. It may provide a noninvasive means for measuring airway inflammation. The aim of this study was to establish reference values for exhaled NO concentrations in a large number of healthy school-age children. We measured exhaled NO levels in 159 white healthy children (88 girls, 71 boys, age range 6-15 years) recruited from two public schools of Padua, Italy. Exhaled NO levels in exhaled gas were measured by a tidal breathing method with a chemiluminescence analyzer, and NO steady-state levels were recorded. Nasal NO levels were measured by direct sampling from the nose during mouth breathing. The mean concentration of endogenous NO in orally exhaled gas was 8.7 parts per billion (ppb) (95% confidence interval (C.I.), 8.1-9.2 ppb) and sampled data followed a log-normal distribution (Kolmogorov-Smirnov d = 0.77, P > 0.2). No difference was found between boys (mean value, 8.4 ppb; 95% C.I., 7.3-9.4 ppb) and girls (mean value, 8.9 ppb; 95% C.I., 7.9-9.9 ppb). No significant correlation was found between age, height, or spirometric data and exhaled NO levels (r < 0.2). The mean value of nasal NO concentrations was 216 ppb (95% C.I., 204-228 ppb). There was no correlation between exhaled and nasal NO values (r = 0.16, P = ns). In conclusion, this study establishes a reference range for exhaled NO values measured by a tidal breathing method in children between age 6-15 years. The observed levels are independent of age, gender, and lung function, and can be used to monitor airway inflammation in asthmatic children.

Adolescent↗
PubMed1999

Effect of natural grass pollen exposure on exhaled nitric oxide in asthmatic children.

Exhaled nitiric oxide (NO) is increased in exhaled breath of asthmatic patients. The aim of this study was to investigate the longitudinal changes of exhaled NO outside and during the pollen season in pollen-allergic asthmatic children. Twenty-one children (age 6 to 16 yr), with a seasonal allergic asthma sensitive to grass pollen, underwent measurements of exhaled NO and pulmonary function before (March), during (May), and after (November) the pollen season. Exhaled NO was measured by a tidal breathing method with a chemiluminescence analyzer and NO steady-state levels were recorded. The timing of the measurements during the pollen season was based on the atmospheric pollen count. Exhaled NO values of asthmatic children were compared with those of 21 sex- and age-matched healthy children. Pulmonary function and symptoms of asthma were also evaluated at each visit. The mean value of exhaled NO before the grass season was 12.7 +/- 5.1 ppb (mean +/- SD), significantly higher when compared with controls (7.8 +/- 2.7 ppb, p < 0.001). In the pollen season there was a significant (p < 0.001) twofold increase in exhaled NO (21.4 +/- 7.6 ppb) that, after the season, returned to values similar (12.8 +/- 5.8 ppb, p = NS) to those found before the season. There were no significant changes in FEV1 before and during the season (98.6% predicted versus 101% predicted, p = NS). We conclude that natural allergen exposure is related to an increase of exhaled NO in asthmatic grass pollen-allergic children even in absence of significant changes in airways function. We speculate that measurement of exhaled NO could be a sensitive noninvasive marker of asthma disease activity.

Adolescent↗
PubMed1999

Endogenous surfactant metabolism in critically ill infants measured with stable isotope labeled fatty acids.

Little is known about endogenous surfactant metabolism in infants, because radioactive isotopes used for this purpose in animals cannot be used in humans. We developed a novel and safe method to measure the endogenous surfactant kinetics in vivo in humans by using stable isotope labeled fatty acids. We infused albumin-bound [U-13C]palmitic acid (PA) and [U-13C]linoleic acid (LLA) for 24 h in eight critically ill infants (mean+/-SD: weight: 3.7+/-1.3 kg: age: 51.3+/-61.6 d) who required mechanical ventilation. The 13C enrichment of PA and LLA in surfactant phosphatidylcholine (PC), obtained from tracheal aspirates, was measured by gas chromatography combustion interface-isotope ratio mass spectrometry. We measured a significant incorporation of both 13C-PA and 13C-LLA into surfactant PC. PC-PA and PC-LLA became enriched after 8.7+/-4.9 h (range: 3.4-17.3) and 10.0+/-7.2 h (range: 3.0-22.4), respectively; the times at maximum enrichment were 49.2+/-8.9 and 45.6+/-19.3 h, respectively. The fractional synthesis rate of surfactant PC-PA ranged from 0.4 to 3.4% per h, whereas the fractional synthesis rate of PC-LLA ranged from 0.5 to 3.8% per h. The surfactant PC-PA and PC-LLA half-lives ranged from 16.8 to 177.7 and 23.8 to 144.4 h, respectively. This method provides new data on surfactant metabolism in infants requiring mechanical ventilation. We found that synthesis of surfactant from plasma PA and LLA is a slow process and that there were marked differences in PC kinetics among infants. This variability could be related to differences in lung disease and could affect the clinical course of the respiratory failure.

Carbon Isotopes↗
PubMed1998

Effect of atmospheric nitric oxide (NO) on measurements of exhaled NO in asthmatic children.

The measurement of exhaled nitric oxide concentrations [NO] may provide a simple, noninvasive means for measuring airway inflammation. However, several measurement conditions may influence exhaled NO levels, and ambient NO may be one of these. We measured exhaled NO levels in 47 stable asthmatic children age 5 to 17 years and in 47 healthy children, gender and age matched. Exhaled [NO] in expired air was measured by a tidal breathing method with a chemiluminescence analyzer, sampling at the expiratory side of the mouthpiece. NO steady-state levels were recorded. In order to keep the soft palate closed and avoid nasal contamination, the breathing circuit had a restrictor providing an expiratory pressure of 3-4 cm H2O at the mouthpiece. To evaluate the effect of [NO] in ambient air, measurements were randomly performed by breathing ambient air or NO-free air from a closed circuit. Breathing NO-free air, exhaled [NO] in asthmatics (mean +/- SEM) was 23.7 +/- 1.4 ppb, significantly higher (P < 0.001) than in healthy controls (8.7 +/- 0.4 ppb). Exhaled NO concentrations measured during ambient air breathing were higher (49 +/- 4.6 ppb, P < 0.001) than when breathing NO-free air (23.7 +/- 1.4 ppb) and were significantly correlated (r = 0.89, P < 0.001) with atmospheric concentrations of NO (range 3-430 ppb). These findings show that 1) exhaled [NO] values of asthmatic children are significantly higher than in healthy controls, and 2) atmospheric NO levels critically influence the measurement of exhaled [NO]. Therefore, using a tidal breathing method the inhalation of NO-free air during the test is recommended.

Adolescent↗
PubMed1998

Effect of topical steroids on nasal nitric oxide production in children with perennial allergic rhinitis: a pilot study.

It has been hypothesized that concentrations of exhaled nitric oxide (NO) may be related to the extent of cytokine-mediated airway inflammation. Recent findings indicate the nasal airways as an important site of NO production. Our objective was to evaluate whether children with allergic rhinitis show different nasal NO levels when compared with normal healthy subjects and the effect of topical steroids and anti-histamine therapy. We have measured the concentration of NO drawn from the nose of 21 children (5-17 years old) affected by perennial allergic rhinitis (house dust mite) out of therapy for at least 3 weeks. Thirteen children were then treated with nasal beclomethasone dipropionate (BDP) (400 micrograms daily) and eight subjects with nasal anti-histamine levocabastine (200 micrograms daily). Measurements were performed before and after 10 days of treatment. As a control group we evaluated 21 healthy children aged 5-15 years. To measure NO we used a chemiluminescence analyser. Before treatment the whole group of children with allergic rhinitis showed a mean (+/- SEM) nasal NO concentration of 267 +/- 18 ppb, significantly higher (P < 0.01) than the control group (186 +/- 15 ppb). The group of children treated with BDP showed, after 10 days of therapy, a significant (P < 0.05) decrease of nasal NO concentration (271 +/- 21 ppb vs. 212 +/- 20 ppb). Indeed, in the group treated with levocabastine, nasal NO concentrations did not present a significant difference (P not significant) compared with baseline (261 +/- 33 ppb and 252 +/- 31 ppb, respectively). These data suggest that (1) children with allergic rhinitis have higher levels of nasal NO than non-atopic controls and (2) intranasal steroid therapy significantly reduces nasal NO production in children with allergic rhinitis. We speculate that the allergic inflammatory response may influence the nasal NO levels and that NO measurements may be a useful marker of nasal inflammation.

Adolescent↗
PubMed1998

The guanine triphosphatase (GTPase) activating protein (GAP)-related domain of the neurofibromatosis type 1 gene is not mutated in neural crest-derived sporadic tumours.

We conducted a mutation analysis of the most conserved region of the neurofibromatosis type 1 (NF1) gene, the guanine triphosphatase (GTPase) activating protein (GAP)-related domain (NF1 GRD), to which the function of tumour suppressor is attributed. Sixty primary neuroectodermal tumours were analysed. The rationale for the study was based on the likelihood of finding structural alterations resulting in loss of function of this region in tumours of neuroepithelial tissues, where the activity of neurofibromin seems to be crucial in regulating the mechanisms of signal transduction and cell transformation mediated by p21 ras. Following analysis of the whole NF1 GRD sequence, no mutations were identified in the tumours analysed. We conclude that the loss of NF1 gene tumour suppressor function, that might lead or contribute to the development of malignancies in neuroectodermal tissues, is not due to structural abnormalities of the region of the gene which interacts with p21 ras.

Base Sequence↗
PubMed1998

In vitro and in vivo antitumor effects of retrovirus-mediated herpes simplex thymidine kinase gene-transfer in human medulloblastoma.

Herpes simplex virus thymidine kinase gene (HSVtk) transfer together with treatment with the prodrug ganciclovir (GCV) represents the most commonly used suicide gene approach for the gene therapy of human central nervous system malignancies. Despite encouraging results reported in clinical trials conducted in adults, very little is known about the feasibility of this approach for the treatment of CNS tumors of childhood. We studied the effects of the HSVtk/GCV system on human medulloblastoma cells in vitro and in vivo. The transfer of tk gene to medulloblastoma cells was capable of mediating cell suicide in vitro and in vivo upon treatment with GCV, but the overall effect in vivo appeared to be suboptimal. The relatively low sensitivity of the medulloblastoma cells to viral infection and a limited bystander effect, coupled with a low expression of connexin-43 protein, might partially explain these results. Whether this is a peculiarity of the cell line studied or a general characteristic of medulloblastoma remains to be determined. These findings should be taken into account for the future planning of gene therapy trials for human medulloblastoma.

Cerebellar Neoplasms↗
PubMed1998

Inhaled nitric oxide in hypoxaemic newborns who are candidates for extracorporeal life support.

The aim of this study was to evaluate the effect of inhaled nitric oxide (NO) in newborns with acute hypoxaemic respiratory failure and the impact of this NO therapy on survival and the need for extracorporeal membrane oxygenation (ECMO). A cohort of newborns with a gestational age of > or = 34 weeks and an oxygenation index (OI) > 25 were prospectively evaluated. Patients were given NO at an initial dose of 10 parts per million (ppm). Oxygenation parameters were evaluated prior and during NO inhalation. From January 1994 to December 1996, 20 infants were enrolled in the study. Based upon their outcome, patients were divided into two groups: survivors with no need for ECMO, group A (n=8) and survivors requiring ECMO or nonsurvivors, group B (n=12). All infants approached or met ECMO criteria before NO inhalation. Eight patients (40%) were successfully managed with NO and conventional treatment (group A). Newborns in this group showed a rapid and sustained improvement of systemic oxygenation during NO inhalation. Mean arterial oxygen tension (Pa,O2) increased significantly from 4.5 kPa (34 mmHg) (95% confidence interval (95% CI) 1.9-7.1 kPa (14.4-53.7 mmHg)) to 10.1 kPa (75.7 mmHg) (95% CI 6.5-13.6 kPa (49.1-1023 mmHg)) after 1 h and was 9.0 kPa (67.7 mmHg) (95% CI 7.1-11.0 kPa (53.1-82.4 mmHg)) at 24 h. Conversely, none of the oxygenation parameters improved in the 12 patients who ultimately required ECMO or died (group B). The results indicate that inhaled nitric oxide can improve systemic oxygenation in newborns with acute respiratory failure and may reduce the need for extracorporeal membrane oxygenation support in candidates. Lack of a rapid response to nitric oxide may be an early predictor of unfavourable short-term outcome, prompting a move towards alternative treatments.

Administration, Inhalation↗
PubMed1998

Successful treatment of recurrent rejection in renal transplant patients with photopheresis.

Photopheresis (ECP) is a new form of photochemotherapy that induces a selective inhibition of the host response to foreign histocompatibility antigens and reverses allograft rejection after organ transplantation. This report describes four adolescent patients with recurrent rejection episodes after renal transplantation, all uncontrolled using standard protocols of immunosuppression (intravenous steroids and OKT3), yet successfully treated with a 6-mo course of ECP. The ECP treatment was performed at weekly intervals during the first month, at 2-wk intervals during the second and third months, and then monthly for another 3 mo. Creatinine clearance improved throughout the treatment in three patients and remained unchanged in one. All patients had a pre-ECP biopsy with a grade 2 or 3 rejection (Banff) with a diffuse infiltrate CD8, CD14, LFA-1 (166 cells positive/0.048 mm2), and VLA-4 (51 cells positive/0.048 mm2) positive, as well as a tubular expression of HLA-DR (6.2 sections of tubule positive/0.048 mm2), ICAM-1, and VCAM-1 (3.1 and 2.9 sections of tubule positive/0.048 mm2). A strong reduction of cell infiltrate and expression of LFA-1 (6.6 cells positive/0.048 mm2). VLA-4 (0.7 cells positive/0.048 mm2), HLA-DR (0.2 section of tubules positive/0.048 mm2), ICAM-1 (0.3 section of tubules positive/0.048 mm2), and a disappearance of VCAM-1 staining were observed in the biopsies performed after 3 mo of ECP. All patients remained rejection-free during ECP, without infections or other complications commonly observed with increasing doses of standard immunosuppression. The clinical improvement allowed a progressive reduction of oral steroids in three of the four patients treated.

Adolescent↗
PubMed1998

Simultaneous HPLC determination with light-scattering detection of lactulose and mannitol in studies of intestinal permeability in pediatrics.

We describe a new HPLC method for the simultaneous determination of lactulose and mannitol in urine, in which cation-exchange chromatography and evaporative light-scattering detection are used. The two sugars are orally administered for the estimation of intestinal permeability in children. Samples were purified by solid phase extraction on a C18 cartridge and subsequent addition of anion-exchange resin. Cellobiose may be used as an internal standard. The chromatographic separation was carried out in 16 min at a flow rate of 0.5 mL/min, using deionized water as the mobile phase. Within-run precision (CV) measured at three concentrations was 1.6-2.3% for lactulose and 1.0-1.9% for mannitol. Between-run CVs were 2.1-4.1% and 1.3-2.7% for lactulose and mannitol, respectively. Analytical recovery of both sugar probes was 97-101%. The detection limits (signal-to-noise ratio = 3) were 0.82 mg/L for lactulose and 0.65 mg/L for mannitol. The lactulose/ mannitol ratio in control subjects was 0.024 +/- 0.006; in patients with Crohn's and coeliac diseases in active phase, the ratios were 0.200 +/- 0.082 and 0.072 +/- 0.025, respectively. The method is rapid, simple, and sensitive, and suitable for determination of intestinal permeability in children.

Administration, Oral↗
PubMed1997

Rapid determination of p-aminohippuric acid in serum and urine by high-performance liquid chromatography.

We report a simple and rapid HPLC procedure for measuring p-aminohippuric acid in serum and urine. After deproteinization with acetonitrile and addition of p-aminobenzoic acid as an internal standard, the chromatographic run is performed on a C18 column with the absorbance detector set at 275 nm. The separation is carried out in 10 min at a flow-rate of 1.0 ml/min with a mobile phase composed of 7 mmol/l 1-decanesulfonic acid, pH 3.70, and acetonitrile (82:18, v/v). The relationship between p-aminohippuric acid concentration and the p-aminohippuric acid/internal standard peak area is linear up to 100 microg/ml. Within-run precision measured at three different p-aminohippuric acid concentrations ranges from 1.73 to 1.98% in serum and from 0.72 to 1.32% in urine. Between-run precision varies from 1.80 to 4.06% in serum and from 1.05 to 2.66% in urine. Analytical recovery is between 98.26 and 99.44% in serum and from 99.57 to 100.45% in urine. The method is very simple, sensitive, and requires small volumes of sample for the assay (100 microl). Therefore, it could be a useful tool for the analysis of p-aminohippuric acid in the evaluation of renal plasma flow.

Adult↗
PubMed1997

Hypertensive cardiomegaly caused by an aldosterone-secreting adenoma in a newborn.

A case of primary hyperaldosteronism and cardiomegaly due to a unilateral adrenal adenoma in a newborn is presented. Some peculiarities, most likely in relation to the onset of the disease during fetal life were evident: plasma cortisol was slightly increased before surgery, plasma renin activity was elevated 9 months after surgery and mineralcorticoid receptors remained suppressed 4 months after surgery. Unilateral adrenalectomy reversed both hypertension and cardiomegaly. We speculate that cardiomegaly was related to both hyperaldosteronism and hypertension and that individual factors are involved in the pathogenesis of cardiomegaly in hyperaldosteronism.

Adenoma↗
PubMed1997

Evoked potentials in pediatrics: economic audit.

In the present era of resource management, there is increasing emphasis on the need to make the best possible use of available resources. We therefore measured the productive factors directly involved in performance of 59 evoked potential examinations (brainstem auditory evoked potentials, BAEPs; flash visual evoked potentials, F-VEPs; and electroretinograms, ERGs) in different pediatric age groups. In order to ascertain the gap between the costs of instrumental examinations performed in our service on children and the fees reimbursed by the Italian national health service (NHS) a breakdown was made of the costs of tests and their scheduling in relation to the different age variables involved. It was found that the fees reimbursed do not cover the real costs, because they underestimate the actual consumption of resources. The findings recorded indicate that for pediatric tests the economic audit should be graded according to the ages of the children examined and should include an analysis of different test phases. The economic audit should also be considered a preliminary step in clinical audit. It is concluded that it is financially punitive to reimburse a pediatric service with a fee based on the examination of adults, because in pediatrics the variable "age" influences the duration and complexity of tests and also their interpretation.

Adolescent↗
PubMed1997

Home oxygen therapy in infants with bronchopulmonary dysplasia: a prospective study.

UNLABELLED: We followed the clinical course of 21 infants with bronchopulmonary dysplasia enrolled in a prospective home O2 therapy programme during a 4-year-period. Mean gestational age was 28.5 weeks (range, 25-36 weeks) and mean birth weight 1093 g (range 630-2750 g). Infants were regularly monitored to maintain pulse oximeter O2 saturation over 94%-95%. The source of O2 was liquid oxygen and was delivered by nasal cannula. During the follow up oxygenation was assessed by SatO2 measurement, cardiac function by Doppler echocardiography and respiratory function by the occlusion technique. All patients had an ophthalmological follow up. The mean age of the infants at discharge was 3.7 months (range 1.7-8.6) and mean weight 2830 g (range 2150-3780 g). At discharge 8 infants had right ventricular hypertrophy (RVH) and four of them had pulmonary hypertension. Mean duration of home O2 therapy was 97 days (range 15-320 days) and the mean age of discontinuation of O2 was 6.9 months (range 3-14.7 months). The cardiological follow up was benign: the ECG signs of RVH disappeared by 12 months of age in six out of eight infants and the right ventricular pulmonary pressure, as measured by the Doppler method, normalised in the four patients in whom it was detected. No relationship was found between respiratory mechanics and the duration of O2 therapy. Weight gain was poor with mean growth at the 3rd percentile for females and just below the 3rd percentile for males. Twelve of the 21 infants required 25 rehospitalizations. No one presented deterioration of retinopathy of prematurity that was present in 16 infants at discharge; at 12 months retinopathy was resolved in 14 infants. A total of 2025 hospital days were saved, representing a significant financial saving. CONCLUSION: Home O2 therapy permits the safe early discharge of O2-dependent BPD infants and it reduces significantly the length of time spent in hospital which represents a considerable financial saving.

Bronchopulmonary Dysplasia↗
PubMed1997

Corticosteroids decrease exhaled nitric oxide in children with acute asthma.

OBJECTIVES: Nitric oxide (NO) produced in human airways seems to have both homeostatic and proinflammatory actions in the respiratory system. NO production has been shown to be higher in the exhaled air of asthmatic adults than in normal subjects. The aim of this study was to evaluate exhaled NO production during asthma exacerbation in children and the effect of a rescue course of oral steroid therapy. STUDY DESIGN: We measured NO in the exhaled air of 16 children (8 girls and 8 boys, aged 6 to 13 years) with an acute asthmatic episode before and after 5 days of therapy with prednisone, and in 16 healthy children. To measure NO, children inhaled NO-free air and, breathing at tidal volume, exhaled in a circuit from which a chemiluminescence analyzer sampled continuously. To assess the effect of acute changes in bronchial caliber on exhaled NO levels, we measured NO before and after a positive bronchodilation test result with albuterol in seven children with asthma whose disease was stable. RESULTS: In the group with acute asthma (forced expiratory volume in 1 second 62% +/- 4.4% predicted, mean +/- SEM), NO levels were significantly higher (31.3 +/- 4.2 parts per billion [ppb]) than in healthy children (5.4 +/- 0.4 ppb, p < 0.001). Administration of prednisone (1 mg/kg per day orally) for 5 days resulted in a mean decrease of 46% +/- 4% in exhaled NO concentrations (16.5 +/- 2.3 ppb, p < 0.001) compared with baseline, accompanied by a significant improvement in lung function (forced expiratory volume in 1 second 90.7% +/- 4.3% predicted). However, in patients with asthma exhaled NO levels remained significantly higher than in control children (p < 0.001) after steroid treatment. When exhaled NO was measured before and after a positive result after bronchodilator reversibility testing, we found no difference in exhaled NO levels (24 +/- 3.8 ppb vs 23.8 +/- 3 ppb; difference not significant). This demonstrates that inhaled albuterol and acute changes in bronchial caliber do not affect exhaled NO measurement. CONCLUSIONS: These data show that children with asthma exacerbation have high levels of exhaled NO that rapidly decrease with oral steroid therapy. We suggest that measurement of exhaled NO may represent a noninvasive method of monitoring airway inflammation in children with asthma.

Acute Disease↗
PubMed1997

ExGen 500 is an efficient vector for gene delivery to lung epithelial cells in vitro and in vivo.

Nonviral vectors might represent a safe alternative to adenovirus for gene therapy of lung disorders, in particular cystic fibrosis (CF). Cationic lipids have been shown to correct the CF defect both in vitro and in vivo, but more efficient vectors are needed to improve the low gene transfer efficiency. Here, we show that the cationic polymer ExGen 500, a linear polyethylenimine derivative, is more efficient than cationic lipids in transferring reporter genes to lung epithelial cells in vitro. In vivo ExGen 500 was able to mediate gene transfer into both newborn and adult rabbit lungs with comparable efficiencies. The best levels of transfection were obtained using neutral complexes. Under such conditions, luciferase activities corresponding to about 10(3) RLU/10 s/mg of protein were reproducibly obtained 2 days after transfection throughout the four lung lobes of newborn and adult rabbits. A nlslacZ reporter gene showed transfected cells around the lumen of large and small bronchi. No signs of acute toxicity (inflammation, cellular infiltration etc) were detected by direct histopathological analysis. Within 1 week after instillation, transgene expression decreased by two orders of magnitude.

Animals↗