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Biomedical subjects

R Ronchetti

Publications and source records attributed to R Ronchetti.

At least 19 recordsLinked to original sources
PubMed1992

Enhanced allergic sensitisation related to parental smoking.

The objective of this study was to assess the role of parental smoking in changes, after a four year interval (1983-7), in the prevalence and severity of the atopic state in 166 pre-adolescent children. Allergy skin prick tests were related to parental smoking habits and their changes during this same interval. The total number of cigarettes smoked by parents decreased in 56 families while it increased in only 16. Boys had significantly more persistently positive skin tests and changed more frequently from negative to positive. The skin test index did not show significant changes in girls. This index did not change in children of persistent non-smokers or those starting to smoke during this period, while it increased among sons of those that quit smoking and of persistent smokers. This was not only due to those boys who became skin test positive during follow up. When analysis was restricted to 14 boys who had been skin test positive in 1983 and whose parents were persistent smokers, the index increased in eight, remained unchanged in four, and decreased in only two. This report supports the hypothesis that parental smoking is a factor that, together with specific allergenic exposure, may enhance allergic sensitisation in children.

Child↗
PubMed1991

Analysis of expiratory pattern for monitoring bronchial obstruction in school-age children.

This study was designed to assess the validity of the percent of volume expired at tidal peak flow (dV/Vt) as an indicator of bronchial obstruction in school-age children. We analyzed 126 dV/Vt ratios and compared them with spirometric and plethysmographic results measured in 24 healthy (14 males) and 60 asthmatic (41 males) children; 42 of them underwent measurements before and after bronchial challenge with histamine. The two groups differed in resistance, forced expiratory volume in 1 sec (FEV1), and forced expiratory flows, as percents of predicted (FEV1: 94.6 +/- 2.4% in controls vs 86.7 +/- 1.6% in asthmatics; P less than 0.001). They did not differ in peak expiratory flow (PEF), forced vital capacity, functional residual capacity, measured by body plethysmography, and in dV/Vt. The dV/Vt was found to correlate with FEV1 (r = 0.58, P less than 0.001), PEF (r = 0.57, P less than 0.001), and other lung function parameters. Forty-two of the asthmatic children performed a bronchoprovocation histamine test. The fall of dV/Vt after histamine was significantly correlated (r = 0.61, P less than 0.001) with the variation in FEV1 and other lung function parameters. We conclude that dV/Vt is a good indicator of bronchial obstruction, as useful in school-age children as in adults and infants, with no need for the subject's cooperation.

Adolescent↗
PubMed1990

Passive smoking in childhood--tobacco smoke.

Prevalence of cigarette smoking varies widely in different countries, ranging, at the age of 13, from 2% to 5% (Sweden, United States) to more than 30% (Australia, Uruguay). Even if the prevalence of smokers among male adolescents is decreasing in western countries, it is increasing among girls and, in developing countries, male adolescent smokers still reach 40% (and up to 70%-80%). The determination of saliva cotinine levels, a product of nicotine metabolism, is an useful indicator of exposure to passive or active smoking. In a study of 210 children aged 9-13 years, we found detectable levels of saliva cotinine in 13% of children who lived in nonsmoking families and denied being regular smokers and in only 60% of children living in families with heavy cigarette consumption. This wide variations of a marker of smoking exposure may explain the differences in reported consequences of tobacco smoke in investigations conducted in different places and on different target populations. We later studied the effects of environmental tobacco smoke (ETS) in a sample of 166 nine-year-old children. The relationship between parental smoking and degree of bronchial responsiveness in males was significant. Also, prick skin test reactivity to allergens was significantly increased in children of smoking parents. Many studies concerning the effects of ETS exposure seem to demonstrate that not only the lungs and not only children are affected even if the difficulty of the epidemiology in such a field must suggest caution in interpreting the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1990

Increased serum IgE and increased prevalence of eosinophilia in 9-year-old children of smoking parents.

We studied the relationship of serum IgE levels and eosinophil counts with passive smoking in 9-year-old, nonselected children from three Italian towns near Rome. Male children of smoking parents had a significantly higher total count and percentage of eosinophils (p = 0.008) and higher IgE levels (p = 0.01) than male children of nonsmoking parents. Prevalence of eosinophilia (defined as greater than or equal to 4% of total white blood cell count) was significantly correlated with the number of cigarettes smoked by parents among boys (p = 0.003) but not among girls (p = 0.20). There was a significant trend (p = 0.008) for prevalence of eosinophilia to increase with increasing levels of serum IgE. For any given level of serum IgE, the frequency of eosinophilia was higher among children of smoking parents than among children of nonsmoking parents. When parental smoking was studied in a multivariable analysis and after controlling for the other variable, it was still significantly associated with eosinophilia in the children of these smoking parents but not with serum IgE levels. We conclude that parental smoking is associated with a significant enhancement of the expression of the most important markers of allergic sensitization in the children of smoking parents. This is particularly evident for boys and may explain, at least in part, the increased frequency of respiratory symptoms in children of smoking parents.

Child↗
PubMed1989

A correction formula for computing specific airway resistance from a single-step measurement.

Specific airway resistance (SRaw) is conventionally determined by multiplying the plethysmographically measured values of airway resistance and functional residual capacity (FRC). An alternative single-step method, which avoids the need for airway occlusion during determination of FRC, has been described by Dab and Alexander. The single-step method provides no correction for resistance or dead space of the apparatus and, as a result, systematically overestimates SRaw. Using 1,000 paired measurements, it was possible to compute a formula for correcting the single-step measurement. This correction formula can be adjusted and applied to measurements made in any laboratory. The unlimited applicability of the proposed correction has been demonstrated by 234 plethysmographic measurements made in the Pediatric Clinic in Rome.

Adolescent↗
PubMed1988

Parental smoking enhances bronchial responsiveness in nine-year-old children.

We studied the relationship between parental smoking habits and atopy and bronchial responsiveness (BR) in 9-year-old, non-selected schoolchildren. A questionnaire on respiratory disease and maternal and paternal smoking habits was administered to one parent. Skin prick tests using the most common allergens present in central Italy, a flow-volume spirometric test, and a bronchial provocation test using carbachol in increasing doses were performed. Male children with smoking parents had significantly increased BR when compared to those whose parents did not smoke (Odds Ratio (OR) = 4.3, p = 0.009). No such significant increase in BR was found in female children of smoking parents (OR = 1.5, p = 0.4). The relationship between BR in children and smoking in parents was stronger in asthmatics (p = 0.02), but was still significant after controlling for asthma and atopy. Bronchial responsiveness was significantly correlated with atopy (p = 0.001). This was also true for nonasthmatic children and for both males and females separately. Male children of smoking parents had increased reactivity to allergens as assessed by the skin prick test index (p = 0.001). It is hypothesized that passive smoking, by increasing the frequency of BR and of atopy, may increase the risk of asthma in childhood and particularly in boys.

Adult↗
PubMed1987

Controlled studies of childhood asthma self-management in Italy using the "open airways" and "living with asthma" programs: a preliminary report.

The concept of self-management for childhood asthma was introduced to Italy through a scientific exchange agreement with the United States. Two self-management programs, Living with Asthma (LWA) and Open Airways (OA), are being evaluated in three studies, two of which (Pilot and Atri-Viterbo) were conducted by the Respiratory Service of the Pediatric Department of the University "La Sapienza" in Rome and one by 14 Italian university pediatric respiratory centers (Project Italia). In October 1985, 20 children and their 40 parents were enrolled in the Pilot Study. One hundred percent of the mothers and children and 70% of the fathers attended all of the sessions. Theoretical knowledge about asthma and knowledge of asthma self-management behavior were assessed three times by a questionnaire: at the beginning of the program, at the end of the program and one year later. Significant improvements in knowledge of asthma and in knowledge of asthma self-management behavior were demonstrated by both parents and children at the end of the program and one year later. Analysis of clinical symptoms and drug consumption indicated a statistically nonsignificant trend towards a reduction of asthma severity in the year after the program. In the Atri-Viterbo study 8229 children were initially screened by a questionnaire. One hundred eighty-two children with asthma (2.4%) were identified and invited to participate in a self-management program. Open Airways was used in a shortened version. Only 29 families in Atri (22% of the eligible families) and 24 families in Viterbo (50%) ultimately agreed to participate in the program. A comparison of these families with those who did not participate showed that higher social status (p less than 0.001) and more severe asthma (p less than 0.05) were significantly associated with participation. Attendance by mothers and children was 78% in Atri and 61% in Viterbo. Only 5% of the fathers regularly attended the program. Parents who received the program registered a statistically significant increase in knowledge of asthma and knowledge of asthma self-management behavior relative to controls (+13% versus -4%; p less than 0.05). Fourteen university-based pediatric respiratory centers participated in Project Italia, in which the LWA and OA programs were compared in both full length and shortened versions (8 versus 4 h). Four hundred children and their families were enrolled in the study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1978

Decreased serum thymic factor activity in asthmatic children.

Serum thymic factor (STF) activity was assayed in 26 young asthmatic patients and in 20 age-and sex-matched controls, in view of the increasing importance attributed to this thymic product in regulating several immune mechanisms. Determinations of total and specific IgE and of other immunoglobulins and skin tests were also performed. Decreased STF activity and high total and specific IgE concentrations were observed in the majority of asthmatic patients. In controls, STF activity was within normal limits in all cases and total and specific IgE concentrations were increased only on one case. The decreased STF activity may be responsible for a possible impairment of cell-mediated immunity and for the increased stimulation of the reaginic system observed in asthmatic patients, via its effects on some T cell subpopulation, namely, suppressor T lymphocytes, which seem particularly sensitive to STF variations. On the basis of these data and of the results of our study, a possible, although speculative, correlation between reduced STF activity and high IgE concentrations in asthmatic patients may be postulated. The reported increased occurrence of autoimmune phenomena in asthmatic patients is in agreement with the hypothesis of a STF-mediated suppressor T-lymphocyte quantitative and/or qualitative defect in this disease.

Asthma↗
PubMed1975

Clinical application of regional lung function studies in infants and small children using 13N.

A technique is described for the investigation of regional lung function in infants and children using 13N and a gamma camera. Boluses of isotopic gas are inhaled and perfused while the lung fields are scanned. The child is lightly sedated and breathes normally throughout. Regional function is assessed in terms of the distribution of gas and blood, and the balance between ventilation and perfusion is estimated by comparing an index of the ventilation per unit volume of ventilated lung with that of perfused lung. The use of the method in 8 infants and children with different clinical problems is described to show its application. The method is capable of defining the severity and localization of any abnormality and may also be useful in showing normal function in suspect areas.

Child, Preschool↗
PubMed1975

Generalized pulmonary hyperinflation and Fallot's tetralogy in a neonate investigated by pulmonary physiological and radioisotopic methods.

An infant is described who presented a complex cardiopulmonary problem which was evaluated with the help of new physiological techniques. the infant was born at term after an emergency Caesarian section for fetal distress and was found to have meconium aspiration. He remained persistently tachypnoeic and hypoxic despite high ambient oxygen. Chest radiography suggested cystic lesions at the lung bases, and lung function tests confirmed hyperinflation with delayed nitrogen washout. In addition the child had signs of Fallot's tetralogy, and this diagnosis was confirmed by cardiac catheterization. Because of persistent hypoxia and tachypnoea disproportionate to the cardiac condition, the possibility of localized lung disease was considered. Regional lung function tests were carried out in the neonatal period and again at six months of age useing radioisotopic 13N given by both inhalation and injection. These studies showed gross ventilation/perfusion imbalance in the lungs, particularly marked at the bases, but with enough generalized abnormality to preclude the possibility of surgical intervention. The principles of the measurement of lung mechanics in the newborn by whole-body plethysmography, nitrogen washout, and regional radioisotopic spirometry are outlined. The particular value of these techniques in the evaluation of complex disorders is discussed, especially where both cardiac and pulmonary abnormalities are present.

Airway Resistance↗
PubMed1975

An analysis of a rebreathing method for measuring lung volume in the premature infant.

Functional residual capacity (FRC) and thoracic gas volume (TGV) were measured in 20 infants, of whom 11 were healthy preterm infants, 5 were recovering from the respiratory distress syndrome (RDS), and 4 had other pulmonary problems. In addition, some of the theoretical aspects of rebreathing techniques, including the lung to bag N2 difference at equilibrium, were studied by constructing a simple digital computer model of the system. In both the normal preterm infants and the post-RDS group, the TGV was significantly greater than the FRC (0.02 greater than P greater than 0.01), indicating the presence of trapped gas (Fig. 2). The mean time taken to reach equilibrium during rebreathng was 44 sec in the normal infants and 52 sec in the post-RDS group (Table 2). In one infant with generalized cystic lung disease, equilibrium was not achieved even after 3 min of rebreathing (Fig. 1). The computer-generated analysis of rebreathing for a normal 3-kg infant is shown in Figure 3, with an in vivo curve for comparison. The rapid equilibration of N2 was completed within 55 sec but, as in the in vivo experiments, there was a change in slope of the line afer 1.7 min. It can be seen from Table 3 that, if a small initial bag volume (11 ml) is used, 30 sec of rebreathing is adequate for equilibration only when FRC and dead space are normal, and errors would occur if either were enlarged. The computer study showed that the gradient for N2 between bag and lung at equilibrium is of the order of 0.2-0.37% which would cause a negligible error when calculating FRC and assuming that lung N2 is equal to the measured bag N2. The combined in vivo and computer studies served to validate the rebreathing technique as a method for measuring FRC, and have enabled it to be modified for use even in small or very sick infants with poor ventilation. The most useful procedure to employ would seem to be to use an initial bag volume of 150-200 ml and to continue the rebreathing for 1.5-2 min, with samples being taken for analysis at approximately 20-sec intervals.

Computers↗