bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beta‐adrenergic receptors of lymphocytes in children with allergic respiratory diseases
Authors: Bittera István , Gyurkovits Kálmán , Falkay György , Eck Erna , Koltai Mátyás 
Published: March 2007

AbstractThe beta‐adrenergic receptor binding sites on peripheral lymphocytes in children with bronchial asthma (n = 16) and seasonal allergic rhinitis (n = 8) were examined in comparison with normal controls (n = 18) by means of 124l‐cyanopindolol. The number of beta‐adrenergic receptors was significantly lower in the asthmatic group (858 ± 460/lymphocyte) than in the controls (1564 ± 983/lymphocyte). The value (1891 ± 1502/lymphocyte in children with allergic rhinitis was slightly higher than that in healthy controls. Of the 24 patients suffering from allergic diseases of the lower or upper airways, the bronchial histamine provocation test was performed in 21; 16 gave positive results, while 5 were negative. No difference in beta‐adrenergic receptor count was found between the histamine‐positive and negative patients. Neither was there any correlation between the number of beta‐adrenergic receptors and the high (16/24) and low (8/24) serum IgE concentrations found in allergic patients. The significant decrease in beta‐adrenergic receptor count in asthmatic children lends support to Szentiványi's concept. Further qualitative and quantitative analysis of lymphocyte beta‐adrenergic receptors may provide an individual approach to the treatment of bronchial asthma with beta‐sympathomimetic drugs.
The effect of age on postpneumonectomy growth in rabbits
Authors: Cagle Philip T. , Langston Claire , Thurlbeck William M. 
Published: March 2007

AbstractTo assess the effect which age at pneumonectomy has on pulmonary compensatory growth, male New Zealand white rabbits underwent left pneumonectomy or sham thoracotomy at 10, 18, or 26 weeks of age. Morphometric and biochemical evaluation of the remaining lungs was carried out four weeks later. There was significant compensatory growth in terms of lung volume, weight, DNA, RNA, and protein in all three age groups. Lung volume response was incomplete, i.e., right lung volume of the experimental animals did not match the volume of both lungs of controls; other variables were not significantly different between the right lung of experimentals and both lungs of the controls. An unchanged surface area per unit volume accompanied by a stable mean linear intercept indicated that alveolar multiplication occurred in the 10 and 18 week age groups. The oldest group had significantly decreased surface area per unit volume and significantly increased mean linear intercept, suggesting an increase in the size of existing alveoli at 26 weeks of age.
Mechanisms of bronchial hyperreactivity in cystic fibrosis
Authors: Van Asperen Peter P. , Manglick Patricia , Allen Hugh 
Published: March 2007

AbstractWe studied 14 patients with cystic fibrosis (CF) who had evidence of bronchial hyperreactivity on a standardized histamine challenge. Patients had a histamine challenge on the first day. Then they were pretreated with either 0.25 mg ipratropium bromide or 0.5 mg fenoterol hydrobromide on 2 separate days, and the histamine challenge was repeated. Baseline forced expiratory volume in 1 sec was similar on the 3 days; however, there was a small but significant (P<0.05) improvement after fenoterol. Mean PC20 on the control day was 1.50 mg/ml, which increased significantly after pretreatment with ipratropium (2.88 mg/ml, P<0.01) and fenoterol (3.64 mg/ml, P<0.005), indicating protection against histamine‐induced bronchial hyperreactivity. The six CF patients with “coexistent asthma,” as defined by recurrent episodes of wheezing responsive clinically to bronchodilator therapy, had no significant protection from ipratropium, whereas the eight “nonasthmatic” CF patients were protected by both ipratropium and fenoterol. We postulate that at least two mechanisms contribute to histamine‐induced bronchial hyperreactivity in patients with CF, one related to vagally mediated reflex bronchoconstriction and another that acts independently of this mechanism.
Inherent variability of pulmonary function tests in infants with bronchiolitis
Authors: Mallol Javier , Hibbert Marienne E. , Robertson Colin F. , Olinsky Anthony , Phelan Peter D. , Sly Peter D. 
Published: March 2007

AbstractDuring the last decade, many new methods of assessing pulmonary function in infants have been introduced. However, considerable controversy has arisen when these different techniques are used to assess the efficacy of various inhaled medications. The currently employed measures of pulmonary function have been reported to have coefficients of variation of less than 10%. However, these figures refer to repeated measurements made in individual babies over a short period of time, with the infant in a constant position. They may not be applicable to studies on the effects of drugs when a significant time interval elapses between measurements, particularly if the infant is repositioned during this time. In the present study, we found that the variability of measurements of thoracic gas volume (TGV), passive respiratory mechanics, and forced expiration approximately doubled if the infant was taken out of the plethysmograph, or repositioned within the plethysmograph, between sets of measurements. The between‐test coefficients of variation ranged from 4.8% to 18.9% for TGV, 7.8% to 23.5% for respiratory system resistance, from 5.0% to 24.1% for respiratory system compliance, and from 10.8% to 36.1% for maximal flow at functional residual capacity. These results demonstrate that the commonly employed infant pulmonary function tests have wide variability in infants with acute wheezing illnesses. Before studying the efficacy of therapeutic interventions in such infants, it is necessary to establish the individual variability of the tests in the infants under the conditions of the study. Failure to do so may result in erroneous conclusions and recommendations.
Activation of alveolar macrophages from children with the acquired lmmunodeficiency syndrome‐related complex
Authors: Clement A. , Sardet A. , Chadelat K. , Grimfeld A. , Tournier G. 
Published: March 2007

AbstractThe ability of alveolar macrophages (AM) to release hydrogen peroxide (H2O2), an indicator of AM function, was studied in five children with the acquired immunodeficiency syndrome (AIDS) related complex and, for comparison, in 11 children without disorders of the lung parenchyma. In the AIDS‐related complex group, pulmonary manifestations were mild, and lung involvement was suspected by moderate clinical and/or radiological features. None had a past history of opportunistic infections; neither did any have lymphopenia. Cytologic study of the bronchoalveolar lavage (BAL) fluid revealed increased cellularity with increased percentage of lymphocytes. The study of H2O2 release was performed on unstimulated AM and on AM stimulated by phorbol myristate acetate (PMA). Under both experimental conditions, the amount of H2O2 accumulated in the medium was significantly increased in the group with AIDS‐related complex (P < 0.001). As no enhanced oxidative activity has been reported in AM from patients with full‐blown AIDS, an increased ability of AM to release oxygen metabolites from children with AIDS‐related complex may reflect an initial and temporary step in the course of the LAV/HTLV‐III pulmonary disease. Determining AM activation might be a reliable method of assessing the evolution of lung disorder in AIDS.
Pulmonary function following mild respiratory tract infections (“common cold”) in teenagers
Authors: Teculescu Dan B. , Pham Quang Thieu , Chau Nearkasèn , Aubry Catherine , Kuntz Claude 
Published: March 2007

AbstractVentilatory function—forced vital capacity (VC)—forced expiratory volume (in 1‐sec forced expiratory flows) static lung volumes, closing volume, and phase III slope (singlebreath N2 test) were compared in 94 children with and 436 children without a history of recent mild acute respiratory infection. Their age ranged from 10 to 16 years; subjects with symptoms on the day of the study were excluded. We found no difference in lung function between the two groups, with the exception of a slight (inconsistently significant) increase in closing volume (CV) and the CV/VC ratio. Although the influence of a persistent increase in interstitial lung pressure leading to early small airways closure cannot be ruled out, this isolated functional abnormality probably represents a spurious positive result, arising by chance when a large number of statistical tests are done.
Respiratory control during nipple feeding preterm infants
Authors: Mathew Oommen P. 
Published: March 2007

AbstractThe present study was designed to investigate the development of respiratory control during feeding in premature infants. Cardiorespiratory disturbances during feeding were evaluated with polygraphic monitoring in 24 premature infants within 1 week of beginning nipple feeds. During the initial study, 15 infants exhibited one or more episodes of short apnea (≥ 10 sec) and three infants exhibited prolonged apnea (≥20 sec). Bradycardia developed in seven infants; apnea and decreases in oxygen saturation invariably preceded the development of bradycardia. In contrast, short apnea occurred during sleep in five infants and associated bradycardia developed in four infants. Occurrence of apnea during sleep was significantly lower than that observed during feeding (P < 0.05). Subsequently, 18 of these infants were reevaluated 7–10 days later. Seven infants developed one or more episodes of short apnea, five developed prolonged apnea, and four developed bradycardia. These occurrences were not significantly different from those observed during the initial study (P > 0.05). Short apnea persisted during sleep in four infants during reevaluation. Most of the apneic episodes in both studies were mixed apnea. The high frequency of cardiorespiratory disturbances during the first 2 weeks of nipple feeding indicates that in most preterm infants respiratory control during feeding is still immature at the postconceptional age of 35–36 weeks.
Airway pressures during crying in healthy infants
Authors: Shardonofsky Felix R. , Perez‐Chada Daniel , Carmuega Esteban , Milic‐Emili Joseph 
Published: March 2007

AbstractMaximal inspiratory and expiratory airway pressures (PI max and PE max) were measured in 100 healthy infants (51 males, 49 females; age range, 0.06–3.76 years) by occluding the airway with a suitable face mask during a crying effort. Mean values ± SD for PI max and PE max were 118 ± 21 cm H2O and 125 ± 35 cm H2O, respectively. Maximal inspiratory pressure was independent of age, sex, and anthropometrics, while maximal expiratory pressure showed a low but statistically significant positive correlation with body weight (P < 0.001).
Predicting arterial oxygen tension from maximum expiratory flow volume curves in cystic fibrosis
Authors: Stecenko Arlene A. , Postotnik Linda , Thomas Ronald G. 
Published: March 2007

AbstractMeasurements of arterial oxygen tension (PaO2) while breathing room air, and maximum expiratory flow volume curves were performed in 34 patients with cystic fibrosis (age range 7–27 years, 24 males and 10 females). Logistic regression was performed using forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), and forced expiratory flow at 75% of expired vital capacity (FEF75) to model an equation for predicting when PaO2 would be less than 55 mmHg (severe hypoxemia). Equations were modelled using one, two, three, or all four of the variables. For the univariate logistic regression, each of the four variables was a significant (P < 0.001) predictor for severe hypoxemia. FVC was the best predictor with an R2 = 0.56, sensitivity of 100% (false negative rate = 0%), and a specificity of 88.5% (false positive rate = 27%). The model predicted that patients with an FVC < 35% of the predicted normal were at risk of having PaO2 ≤ 55 mmHg. Adding FEV1, FEF75, or PEFR in various combinations to FVC made the model equation more complicated but did not add significantly to the ability to predict severe hypoxemia.
Reducing inadvertent peep by controlling end‐tidal pressures in the trachea
Authors: Gonzalez Felipe , Carlstrom Jeffrey , Richardson Peter 
Published: March 2007

AbstractMechanical ventilation using exhalation times too brief for completion of exhalation results in inadvertent positive end‐expiratory pressure (IPEEP) and increased functional residual capacity (FRC). The endotracheal (ET) tube with side lumen allows us to monitor tracheal airway pressures and to determine the contributions of the ET tube to IPEEP. We hypothesized that, during rapid rate ventilation, controlling the positive end‐expiratory pressure (PEEP) level in the trachea rather than at the ET tube adaptor will counter effects of the ET tube on IPEEP and result in less increase of FRC.Thirteen anesthetized rabbits were ventilated at rates of 30, 60, 90, and 120 breaths per minute (BPM). Peak inspiratory pressure was held constant, and PEEP was adjusted to 2 cmH2O, measured conventionally at the proximal end of the ET tube. Pulmonary function tests were made and then repeated while PEEP was held constant in the trachea, measured at the distal end of the ET tube.Controlling PEEP conventionally resulted in mean (± SE) FRC values of 13.7 ± 3.8, 14.8 ± 3.9, 17.1 ± 4.5, and 21.1 ± 5.3 ml/kg at 30, 60, 90, and 120 BPM, respectively. Controlling PEEP at the trachea yielded FRC values of 13.7 ± 3.8, 13.6 ± 3.4, 15.3 ± 4.4, and 16.3 ± 5.4 ml/kg, respectively. Increasing the ventilator rate above 60 BPM did not affect minute ventilation or blood gases.These results suggest that controlling PEEP in the trachea reduces effects of IPEEP on FRC by countering the contribution of the ET tube to the resistance of gas flow during exhalation.
Mechanics and energetics of breathing in newly diagnosed infants with cystic fibrosis: Effect of combined bronchodilator and chest physical therapy
Authors: Hardy Karen A. , Schidlow Daniel V. , Wolfson Marla R. , Shaffer Thomas H. 
Published: March 2007

AbstractResponse to bronchodilator (BD) and chest physical therapy (CPT) was evaluated in newly diagnosed infants with cystic fibrosis (n = 13; age, 6.9 ± 1.5 SE months) who were asymptomatic for lung disease at the time of the study. Lung function was assessed from the mechanics and energetics of breathing prior to and following combined BD and CPT. After therapy, respiratory rate, tidal volume, minute ventilation, and pulmonary compliance were not statistically different from values under baseline conditions. In contrast, there was a significant decrease in pulmonary resistance (‐34%; P <0.05) and the resistive work of breathing (‐26%; P <0.05) following the combined treatment. The effect of combined BD and CPT in decreasing the resistive respiratory load may be related to relief of subclinical bronchospasm, reduction in mucosal edema, and mobilization of mucous secretions.
Prenatal relationship of surfactant lipid and protein constituents in infants with respiratory distress syndrome: A preliminary communication
Authors: Wilbur Deborah B. , Kanarek Keith S. , Balis John U. , Paciga June E. , Shelley Sue A. , Cohen Gary 
Published: March 2007

AbstractThe prenatal relationships between surfactant disaturated phosphatidylcholine (DSPC) and surfactant‐associated proteins of preterm infants with respiratory distress syndrome (RDS) have not been well documented. In the present study we measured the concentration of DSPC, surfactant glycoproteins (GP), and surfactant proteolipids (PLP) in amniotic fluids obtained within 6 hours prior to delivery of 16 newborn infants with gestational ages between 27 and 32 weeks. In control infants of 27–32 weeks gestation without RDS, the values of DSPC, GP, and PLP per milliliter of amniotic fluid were 20 ± 2.9 μg, 684 ± 115.3 ng and 289 ± 62.5 ng, respectively. These values were significantly higher, threefold for PLP, fourfold for DSPC, and fivefold for GP, than amniotic fluid levels in infants with RDS. The findings support the concept that immaturity of surfactant in RDS involves both phospholipids and surfactant‐associated proteins. Measurements of surfactant lipid‐protein complex appear to enhance the reliability for identifying prenatally, infants at risk of developing hyaline membrane disease. More extensive studies are warranted to assess the usefulness of these assays for clinical application.
The reproducibility and agreement of three indices of airway responsiveness to histamine in asthmatic children
Authors: van Aalderen W. M. C. , Gerritsen J. , Knol K. , Koëter G. H. , Postma D. S. , van der Weele L. T. 
Published: March 2007

AbstractIn 12 asthmatic children, aged 8–14 years, we investigated the possibility of using a provocation concentration of histamine (PC) causing a 10% or 15% fall in baseline forced expiratory volume in 1 sec (FEV1), instead of a PC20 histamine, in the assessment of bronchial hyperreactivity. Inhalation challenge tests were performed on days 6 and 7 after withdrawal of medication. PC10, PC15, and PC20 were calculated from the dose‐response curves.Reproducibilities for PC10, PC15, and PC20, values for both days, determined by Student's t‐test, were not significantly different. Correlation coefficients between PC20 and PC15 values on days 6 and 7 and between PC10 values on days 6 and 7 were 0.82 and 0.76, respectively; between PC20 values on day 6 and PC15 values on day 7; and between PC20 values on day 6 and PC10 values on day 7 they were 0.84 and 0.82, respectively. (P <0.01 for all r values).The predictive value of PC20 for PC10 and PC15 was determined by a least‐squares regression line with 95% confidence intervals. Variances between PC10, PC15, and PC20, were not significantly different on either day 6 or 7.Our data show that a PC10, as well as a PC15, can be used in the assessment of the degree of bronchial hyperreactivity in children with asthma.
A correction formula for computing specific airway resistance from a single‐step measurement
Authors: Haluszka Janusz , Willim Grzegorz , Filtcher Slavi , Cutrera Renato , Ronchetti Roberto 
Published: March 2007

AbstractSpecific 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.5,6 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.
Estimation of maximum expiratory flow‐volume variables in children
Authors: Houthuijs Danny , Remijn Bregt , Brunekreef Bert , Koning Rian De 
Published: March 2007

AbstractDifferent protocols for pulmonary function testing were evaluated in 611 children, 6–9 years old. Attention was paid to the necessary minimum number of acceptable maneuvers, the necessary maximum number of attempts, and the best of seven different methods for summarizing variables from maximum expiratory flow‐volume (MEFV) curves. The results of the study indicate that it is not useful to continue pulmonary function testing after eight attempts. The differences between the results from three or five acceptable maneuvers are not substantial for any method; in children, obtaining three acceptable curves seems sufficient. When flow variables are selected from one acceptable curve, as in the American Thoracic Society (ATS) guidelines, the reproducibility is somewhat less good than in methods in which results of various curves are averaged or selection is made from different curves. The method that has been recommended by the European Community for Coal and Steel for the selection of MEFV variables in teenagers and adults in Europe, was also demonstrated to be suitable for younger children.
Nontypable Haemophilus influenzae nosocomial pulmonary infections in children following intubation
Authors: Hicks Ralph A. , Burry V. Fred , Olson Lloyd C. , Jackson Mary Anne 
Published: March 2007

AbstractTwenty‐nine intubated pediatric patients were prospectively studied to determine whether nontypable Haemophilus influenzae (NTHI) is associated with the development of nosocomial pneumonia. Throat cultures and tracheal Gram stains, leukocyte counts and cultures were obtained immediately following intubation, then serial studies on tracheal secretions were performed. Median patient age was 13 months. One patient had preexisting lung disease and 14 (48%) had pneumonia when intubated. There were five deaths. NTHI was recovered from the initial throat or tracheal culture in seven patients (24%); none developed a nosocomial lower respiratory tract infection. NTHI was not associated with any of three cases of nosocomial pneumonia. Three of 12 NTHI isolates were beta‐lactamase producers. Tracheal leukocyte counts and Gram stains were not predictive of pneumonia, either at the time of intubation or subsequently. We conclude that NTHI in the oropharynx or trachea is not predictive of pneumonia among intubated pediatric patients.
Characterization of prolonged apneic episodes associated with respiratory syncytial virus infection
Authors: Pickens Deborah L. , Schefft Georgia L. , Storch Gregory A. , Thach Bradley T. 
Published: March 2007

AbstractWe used high‐speed polygraphic recordings to document in detail the sequence of events during prolonged apneic spells in two infants with respiratory syncytial viral (RSV) infection. Also, we elicited upper airway reflexes by stimulating the airway with saline during sleep. Spontaneous prolonged apneic spells were recorded in both infants, and these consisted of two distinctly different apnea types. A number of similarities between apnea of prematurity, upper aiway reflex apnea and the apneas in these two infants with RSV infection suggests the possibility that these various kinds of apnea may have related causal mechanisms.
Changes in the spatial distribution of pulmonary blood flow during the fetal/neonatal transition: an in vivo study in the rabbit
Authors: Lipsett Jill , Hunt Kerri , Carati Colin , Gannon Bren 
Published: March 2007

AbstractThe spatial distribution of pulmonary blood flow was investigated in term fetal and neonatal rabbit littermates, using the plasma tracer fluorescein‐isothiocyanate bovine serum albumin (FITC‐BSA). A tracer bolus was injected intravenously and allowed 2 minutes to circulate in vivo, prior to arrest of the circulation and tissue preparation.In the fetus, fluorescence was only present in 43% of the lung volume, contained within discrete regions or “lobules.” Some 57% of lung volume received no tracer inflow at all (during 2 min). In the fetal lung, the size of the potential airspaces in the perfused regions was 1.5 times larger than those in the nonperfused regions.In the fetus, a high pulmonary vascular resistance (PVR) is maintained. It is generally accepted that pulmonary blood flow in the fetus is evenly distributed to the entire vascular bed. Our results show that fetal pulmonary blood flow is distributed to discrete “lobules,” while (over a 2 min period) the majority of “lobules” receive no flow at all. Thus, by directing flow to a lesser proportion of the vasculature, greater flow rates are achieved, and the risk of blood sludging and stasis is reduced. Alternation of perfusion with nonperfusion in each “lobule,” perhaps regulated by the lobular arterioles, would permit both maintenance of the high fetal PVR and uniform lung development.In the neonatal lung, the plasma tracer was distributed uniformly to the entire vascular bed. This suggests that some of the reduction in PVR at birth is due to recruiting 50–60% of lung vasculature.