bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facile synthesis of dumbbell‐shaped dendritic‐linear‐dendritic triblock copolymer via reversible addition‐fragmentation chain transfer polymerization
Authors: Ge Zhishen , Chen Daoyong , Zhang Jingyan , Rao Jingyi , Yin Jun , Wang Di , Wan Xuejuan , Shi Wenfang , Liu Shiyong 
Published: March 2007

AbstractWe report the first instance of facile synthesis of dumbbell‐shaped dendritic‐linear‐dendritic triblock copolymer, [G‐3]‐PNIPAM‐[G‐3], consisting of third generation poly(benzyl ether) monodendrons ([G‐3]) and linear poly(N‐isopropylacrylamide) (PNIPAM), via reversible addition‐fragmentation chain transfer (RAFT) polymerization. The key step was the preparation of novel [G‐3]‐based RAFT agent, [G‐3]‐CH2SCSSCH2‐[G‐3] (1), from third‐generation dendritic poly(benzyl ether) bromide, [G‐3]‐CH2Br. Due to the bulky nature of [G‐3]‐CH2Br, its transformation into trithiocarbonate 1 cannot go to completion, a mixture containing ∼80 mol % of 1 and 20 mol % [G‐3]‐CH2Br was obtained. Dumbbell‐shaped [G‐3]‐PNIPAM310‐[G‐3] triblock copolymer was then successfully obtained by the RAFT polymerization of N‐isopropylacylamide (NIPAM) using 1 as the mediating agent, and trace amount of unreacted [G‐3]‐CH2Br was conveniently removed during purification by precipitating the polymer into diethyl ether. The dendritic‐linear‐dendritic triblock structure was further confirmed by aminolysis, and fully characterized by gel permeation chromatography (GPC) and 1H‐NMR. The amphiphilic dumbbell‐shaped triblock copolymer contains a thermoresponsive PNIPAM middle block, in aqueous solution it self‐assembles into spherical nanoparticles with the core consisting of hydrophobic [G‐3] dendritic block and stabilized by the PNIPAM central block, forming loops surrounding the insoluble core. The micellar properties of [G‐3]‐PNIPAM310‐[G‐3] were then fully characterized. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1432–1445, 2007
New highly luminescent cationic polyelectrolytes based on poly(phenylenevinylene‐alt‐fluorenevinylene) or poly(fluorenevinylene) derivatives and their neutral precursors
Authors: Mikroyannidis John A. , Barberis Vasilis P. 
Published: March 2007

AbstractPoly(phenylenevinylene‐alt‐fluorenevinylene) (PF) or poly(fluorenevinylene) (F) derivatives that carried alkyl chains with terminal tertiary amino groups were successfully synthesized via Heck coupling. They were postquaternized by reacting with bromoethane to the corresponding cationic polyelectrolytes PFQ and FQ. The neutral polymers PF and F as well as the quaternized polymer FQ were soluble in common organic solvents such as THF, chloroform, dichloromethane, and toluene. In contrast, the quaternized polymer PFQ did not dissolve in these solvents but was soluble in environmentally friendlier solvents like water and alcohols. The neutral precursors exhibited higher thermal stability and glass‐transition temperatures than the corresponding quaternized counterparts. All polymers emitted intense blue‐greenish light in solution (462–489 nm) with relatively high photoluminescence (PL) quantum yields 0.32–0.57, and as thin films (475–557 nm) with optical band gaps of 2.48–2.57 eV. The water soluble PFQ could find potential applications as chemo or biosensor. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1481–1491, 2007
The assessment of pulmonary arterial pressures in bronchopulmonary dysplasia by cardiac catheterization and M‐mode echocardiography
Authors: Newth C. J. L. , Gow R. M. , Rowe R. D. 
Published: March 2007

AbstractSevere (Stage IV) bronchopulmonary dysplasia (BPD) has been associated with pulmonary hypertension and right heart failure, with a mortality rate of 39%. Recently, M‐mode echocardiography has been used to measure right‐sided systolic time intervals (the ratio of right ventricular pre‐ejection period to ejection time; RVPEP/RVET), with a value > 0.35 predicting pulmonary hypertension. This measurement has also been used to predict outcome of BPD and response to oxygen therapy. A retrospective study of six infants with Stage IV BPD who had had cardiac catheterizations and M‐mode echocardiography is reported. By catheterization criteria, four of the six had pulmonary hypertension. By echocardiographic criteria, only two of the six had unequivocally prolonged RVPEP/RVET ratios, and correlations with mean or diastolic pulmonary arterial pressures were poor (0.069 and 0.255, respectively). The validity of M‐mode echocardiography in the assessment of the pulmonary vascular bed in Stage IV BPD is open to debate, and its role in predicting outcome and response to therapy is unknown.
Refractoriness to bronchoconstriction following hyperventilation with cold dry air
Authors: Soto Manuel E. , Schnall Robert , Landau Louis I. 
Published: March 2007

AbstractFifteen subjects undertook repeated periods of hyperventilation of cold dry air and hyperventilation of warm humidified air followed by cold dry air. Hyperventilation of cold dry air induced a biphasic response with initial bronchodilatation followed by bronchoconstriction. However, exercise produced a greater rise in forced expiratory volume in 1 second (FEV1) than hyperventilation alone. Hyperventilation of cold dry air resulted in a period of refractoriness to a second stress of the same type. Refractoriness induced by exercise or hyperventilation of cold dry air may be the result of refractoriness of the trigger site in the large airways.
The role of piperacillin therapy in pulmonary exacerbations of cystic fibrosis: A controlled study
Authors: Macfarlane P. I. , Hughes D. M. , Landau L. I. , Olinsky A. 
Published: March 2007

AbstractPiperacillin was evaluated as an antipseudomonas antibiotic in a double‐blind controlled trial involving 18 pulmonary exacerbations of cystic fibrosis. Standard antibiotic treatment (flucloxacillin plus tobramycin) was compared with standard treatment plus intravenous piperacillin administered according to two regimens. No added benefit from piperacillin was demonstrable on the basis of improvement in symptoms, physical signs, weight gain, pulmonary function tests, radiologic signs, or sputum Pseudomonas bacterial counts. Some patients experienced sensitivity reactions to piperacillin. In vitro, piperacillin was a potent antibiotic against all β‐lactamase‐producing mucoid strains of Pseudomonas aeruginosa; however, in spite of the fact that adequate serum antibiotic concentrations were achieved, sputum bacterial counts did not correlate with either the clinical status or the use of piperacillin therapy. (Key words: combined parenteral antibiotics;cystic fibrosis; dosage intervals; /3‐lactamase‐pos. mucoid ps. a.; piperacillin effectiveness;piperacillin with probenicid.) Pediatr Pulmonol 1985; 7:249‐255.
The value and safety of percutaneous lung aspiration for children with serious pulmonary infections
Authors: Berge Rolando , Arango Leon 
Published: March 2007

AbstractIt is often difficult to establish the etiology of pulmonary infections in children. The diagnostic value and safety of percutaneous needle aspiration of the lung were investigated in 98 children who were suspected of having a bacterial pulmonary infection and who were seriously ill or had failed to respond to apparently adequate empiric antimicrobial therapy. The etiology of the pulmonary infection was established in 60 patients (61%); in the remaining 38 cases (39%) no bacterial microorganisms were recovered from the lung aspirate. Twenty‐four (40%) patients in whom the pathogen(s) were identified were already receiving empiric antimicrobial therapy, and in 18 (66%) the original therapeutic regimen had to be changed to optimally treat the isolated microorganism(s). A total of 11 complications occurred in 10 children (10%): 9 pneumothoraces and two instances of mild, self‐limited hemoptysis. Six of the pneumothoraces (66%) required treatment by either a thoracostomy and chest‐tube or simple percutaneous aspiration. There were no deaths related to the procedures. It was concluded that percutaneous needle aspiration of the lung in children is a potentially useful and reasonably safe technique for the diagnosis of pulmonary infection in carefully selected cases when an exact etiologic diagnosis is needed.
Aerosol delivery to the rabbit lung with an infant ventilator
Authors: Flavin M. , Macdonald M. , Dolovich M. , Coates G. , O'Brodovich H. 
Published: March 2007

AbstractLittle is known about delivery of aerosolized medications to infants undergoing assisted positive pressure ventilation. To assess delivery of medications to the lung with an infant ventilator (Bournes LS104), 27 experiments were performed on anesthetized adult rabbits. Lung deposition was determined by using aerosol radiolabeled with 99m technetium sulfur colloid. Initially a traditional nebulizer was studied and very inefficient delivery to the lung was observed (0.19 ± 0.10 SD% of the initial nebulizer dose). Subsequent experiments using a nebulizer that generates submicronic aerosol particles, at equivalent aerosol output, achieved a highly significant increase in delivery (1.96 ± 1.19 SD%, P < 0.001). Our experiments demonstrated that modifications to traditional nebulizer systems can enhance delivery of aerosolized medication to the lungs of rabbits.
Primary central alveolar hypoventilation in a child: Early diagnosis during acute illness; trials with respiratory stimuli; studies related to endorphins
Authors: Moss Immanuela R. , Cataletto Mary , Winnik Giora E. 
Published: March 2007

AbstractPrimary central alveolar hypoventilation (PCAH) has been described in adults, children, and infants. It is usually diasnosed clinically at an advanced stage when the secondary effects of chronic hypoxia and hypercapnia become evident. We report here PCAH in its early stage in a 7‐year‐old child, whose disease appeared as acute respiratory failure during an acute illness. When the acute illness subsided, the salient features of PCAH remained and were studied in some detail. We also describe the child's response to respiratory stimuli, and some results related to endorphins, including his plasma endorphin levels and response to a trial of naloxone.
Diurnal variation of peak expiratory flow rate in asthmatic children
Authors: Sly Peter D. , Hibbert Marienne E. , Landau Louis I. 
Published: March 2007

AbstractA diurnal variation in peak expiratory flow rate (PEFR) has been described in normal and asthmatic adults. This variation has been apparent in data reported from children, but the rhythm has not been characterized. Sixty‐eight asthmatic children recorded PEFR three times a day for 4 weeks at home. Data were analyzed using paired t‐tests, cosinor analysis, and spectral analysis. Fifty subjects (73.5%) had significant diurnal variations in PEFR on paired t‐tests. Mean amplitude, derived from cosinor analysis, was 22.6% (SD = 13.2%) of mean PEFR. The troush of the PEFR rhythm occurred at 0345 hours for the sroup. Spectral analysis confirmed that the major component of the variation in PEFR was due to a rhythm with a period of 24 hours. The amplitude of the diurnal variation was not related to the subjects' age, sex, or medications taken but was inversely related to mean lung function (expressed as percentage predicted).
Normocarbic hyperventilation fails to induce pulmonary vasodilation
Authors: Lindenberg Jeffrey A. , Goetzman Boyd W. , Milstein Jay M. , Bennett Stephen H. 
Published: March 2007

AbstractThe pulmonary vasodilator effect of increased rate of mechanical ventilation, with and without respiratory alkalosis, was studied in chronically instrumented newborn lambs. Pulmonary hypertension was first induced by ventilating with a hypoxic gas mixture. Subsequent respiratory alkalosis caused significant decreases in pulmonary arterial pressure and pulmonary vascular resistance. When normocarbia was re‐established by adding carbon dioxide to the inspired gas, with the ventilator rate being held constant, the pressure and resistance returned to the baseline hypertensive state. Therefore, mechanical factors, either direct or indirect, appear to be of minor importance in the mechanism of pulmonary vasodilation secondary to frequency‐induced hyperventilation.
Protective value of BCG vaccination in children in Bangkok, Thailand
Authors: Chavalittamrong Burana , Chearskul Sanay , Tuchinda Montri 
Published: March 2007

AbstractThe protective effect of bacille Calmette‐Guérin (BCG) vaccination asainst tuberculosis is controversial. In a study, 330 patients less than 12 years of age with tuberculosis, 52.1% of whom had had BCG vaccination, were compared with a control group of 1106 patients free of tuberculosis, 81% of whom had BCG vaccination. The occurrence of disseminated forms of tuberculosis, tuberculous meningitis, tuberculous peritonitis, and tuberculosis of bone and joints in BCG‐vaccinated patients was quite low. With BCG vaccination, the incidence of the disseminated form of tuberculosis was significantly lower than that of pulmonary tuberculosis with pulmonary parenchymal lesions, primary pulmonary complexes, and pleural effusion. Tuberculous peritonitis was significantly less frequent than pulmonary tuberculosis with pulmonary parenchymal lesions, enlarged hilar glands, pulmonary primary complex, and pleural effusions. The study demonstrated that BCG gave an overall protective effect of 74% and that a major effect of this immunity was to produce a localized form of tuberculosis.
Does nifedipine affect the diurnal variation of asthma in children?
Authors: Sly Peter D. , Olinsky Anthony , Landau Louis I. 
Published: March 2007

AbstractDiurnal variations in airway caliber and in bronchial reactivity have been described. The mechanisms underlyins these variations are not known. The hypothesis that these variations can be diminished by calcium channel blockers was tested by giving 22 asthmatic children 10 mg of nifedipine or identical placebo three times a day for 4 weeks in a double‐blind, randomized, crossover‐designed study. Treatment with nifedipine did not diminish the diurnal variations in airway caliber, judged from peak expiratory flow rates, or in bronchial reactivity, judged from bronchodilator responsiveness. Group mean amplitude of the diurnal variation in airway caliber was 10.5% on nifedipine and 10.6% on placebo. Group mean amplitude of the diurnal variation in bronchodilator responsiveness was 75.4% on nifedipine and 69.5% on placebo. There were no differences in mean peak expiratory flow rate between nifedipine and placebo periods. This study did not find any evidence to support the hypothesis that the diurnal variations in airway caliber and in bronchial reactivity can be diminished by calcium channel blockers.
Aminophylline reduces hypoxic ventilatory depression without increasing catecholamines
Authors: Bruce R. Dean , Darnall Robert A. , Althaus John S. 
Published: March 2007

AbstractAminophylline reduces hypoxic ventilatory depression in newborn piglets and can enhance the release of catecholamines (CATs), which in turn may stimulate ventilation. To determine if the effect of aminophylline on ventilation was due to the release of CATs, we measured plasma CATs and ventilation in two groups of spontaneously breathing newborn piglets less than 4 days old, treated with either aminophylline (n = 7) or normal saline solution (n = 6) during both normoxia and hypoxia. The piglets were anesthetized with ketamine and xylazine and intubated, and the femoral artery was catheterized. Epinephrine and norepinephrine were measured before and 30 minutes after treatment with aminophylline (15 mg/kg) or normal saline. The animals were exposed to 10% oxygen and the CATs again measured after 5 minutes of hypoxia. Respiratory rate, expiratory flow integrated to minute ventilation (VE), heart rate, and blood pressure were continuously recorded. CATs were assayed by high‐pressure liquid chromatography with electrochemical detection. Treatment with aminophylline during normoxia was associated with an increase in tidal volume. During hypoxia, treatment with aminophylline prevented a fall in VF and respiratory rate seen in the normal saline group. Epinephrine and norepinephrine increased during hypoxia, but there was no difference between the groups at 5 minutes. In our model the increase in CATs observed during hypoxia was not enhanced by aminophylline. This is consistent with the hypothesis that some mechanism other than catecholamine release is responsible for the effect of aminophylline in reducing neonatal hypoxic respiratory depression.
Congenital tracheal stenosis with associated cardiopulmonary anomalies: Report of two cases with a review of the literature
Authors: Voland Joseph R. , Benirschke Kurt , Saunders Brian 
Published: March 2007

AbstractWe present two infants with congenital tracheal stenosis with complete tracheal rings. Both had associated congenital anomalies. The first case showed cardiac malformations, and the second case had agenesis of the right lung. We review the literature, in particular with reference to tracheal stenosis and pulmonary agenesis. We also propose that the constellation of anomalies may result from defects in the cervical mesenchyme and, as such, may represent one end of a spectrum of cervical mesenchymal field defects.
Modification of nonspecific bronchial reactivity in hypothyroid children under different regimens of substitutive opotherapy
Authors: Villa M. P. , Bernardi F. , Macri F. , Alonge C. , Cacciari E. , Cerimoniale G. , Criscione S. , Ronchetti R. 
Published: March 2007

AbstractAlthough it has been experimentally proved that thyroid hormones stimulate beta2 receptor activity and tissue responsiveness to catecholamines, previous studies have established that asthma and nonspecific bronchial reactivity (NSBR) can worsen if complicated by hyperthyroidism. Our study is an effort toward the analysis of this contradiction. In 20 congenitally hypothyroid children, substitutive opotherapy was completely withdrawn for 1 month, resumed in the original dosage for 2 months, and then increased by 20% from day 91 to day 110. Mean NSBR, expressed in carbachol‐related PD20‐FEV1 and PD25‐V25, was significantly increased by day 30, remained significantly elevated by day 90, and returned to initial values by day 110. These results suggest that thyroid hormones per se in nonasthmatic subjects decrease bronchial reactivity. This observation should be taken into consideration when attempting to explain the worsening condition of asthmatics who become affected with hypothyroidism. Bronchial reactivity appears to be under the control of many factors (including thyroid hormone levels). Once it is altered, a period of time seems necessary to restore the original bronchomotor tone (2 months in our study).
Forced expirations against a variable resistance: A new chest physiotherapy method in cystic fibrosis
Authors: Oberwaldner Beatrice , Evans Johannes C. , Zach Maximilian S. 
Published: March 2007

AbstractTwenty patients with cystic fibrosis (CF) were trained to mobilize intrabronchial secretions by a new method of positive expiratory pressure mask (PEP mask) physiotherapy (PT). Patients repeatedly expired forcefully through the PEP mask; expiratory resistance was varied by eight different internal diameter resistors at the outlet. Forced vital capacity with the mask (FVCPEP) was determined for each resistor and was compared with the one measured without the instrument (FVC); simultaneously the sustained expiratory pressure (SEP) developed against the resistance was recorded. After training, each patient exceeded FVC with one or more resistors; “optimum” FVCPEP was 124 ± 16% FVC at a SEP of 61 ± 21 cm H2O. Using the PEP mask, patients cleared a higher percentage of their daily sputum volume than with conventional PT (78 ± 22% versus 53 ± 17%, p < 0.01). In 11 patients (subgroup 1), multiple aspects of lung function were measured at the beginning of the study, after 10 months with PEP mask PT, after two further months without using the mask but with conventional PT, and after six more months with PEP mask PT. Results showed significantly increased expiratory flow rates, significantly decreased hyperinflation and airway instability with PEP mask PT, and a marked decline of lung function without it. The remaining nine patients (subgroup 2) entered into the same protocol; based on findings in subgroup 1 and on ethical considerations, however, the control period without PEP mask PT was then omitted, resulting in a steady and statistically significant improvement of lung function over the entire observation period. In the course of preliminary trials, two children transiently used a suboptimal resistance (FVCPEP < FVC) and responded with a deterioration of lung function. By dilating airways and evacuating trapped gas, this method of PEP mask PT improves lung function and mucus clearance in CF. Thorough practice with the technique and frequent control of the optimal resistance are mandatory.
Differences in drug susceptibility between isolates of pseudomonas cepacia recovered from patients with cystic fibrosis and other sources and its relationship to beta‐lactamase focusing pattern
Authors: Aronoff Stephen C. , Labrozzi Pauline H. 
Published: March 2007

AbstractPseudomonas cepacia, a significant pulmonary pathogen among children with cystic fibrosis (CF), often possesses an inducible β‐lactamase. The β‐lactamase isoelectric focusing pattern and β‐lactam susceptibility of CF and non‐CF isolates of P. cepacia were compared. Against all of the test strains, ceftazidime and piperacillin were more effective than aztreonam. More CF isolates were resistant to 8 μg/ml of ceftazidime than non‐CF isolates. Isoelectric focusing of cefoxitin‐induced, cell‐free preparations of the CF isolates produced significantly more bands than comparable preparations of non‐CF isolates. Organisms producing a β‐lactamase band that focused in the pH range of 8.5 to 8.7 were significantly more resistant to 8 μg/ml of ceftazidime than other isolates. The increased resistance of CF isolates of P. cepacia to ceftazidime may be the result of the production of a specific bacterial β‐lactamase.
Exhalation time effects on arterial and venous blood oxygen content and arterial P during high frequency jet ventilation of surfactant‐depleted cats
Authors: Johnston Jerrilyn , Carlstrom Jeffrey R. , Gonzalez Felipe , Richardson Peter 
Published: March 2007

AbstractSince high frequency jet ventilation (HFJV) relies on lung mechanics for the passive removal of expiratory gas, one would predict that the time allowed for exhalation would have serious effects on cardiopulmonary function. To document these effects we lavaged the lungs of ten cats with 30 ml/kg of saline six times, then sampled arterial and venous blood while the animals were ventilated conventionally at 30 BPM and then with HFJV at 600 BPM, varying inspiratory/expiratory ratios (I/E) from 1:1 to 1:5. The animals breathed 100% O2 throughout the study, and the mean airway pressure was held constant for each animal when the I/E was varied during HFJV. Decreasing the I/E from 1:1 to 1:5 during HFJV resulted in an increase of arterial oxygen content (Ca) from 11.3 ± 1.2S E to 13.6 ± 1.2 ml O2/100 ml blood (P < 0.01), a decrease of Pa from 43 ± 6 to 27 ± 4 mm Hg, and an increase of alveolar to arterial oxygen gradient from 351 ± 49 to 377 ± 49 mm Hg. The ratio of systemic blood flow to oxygen consumption (Q̇/V̇) was similar during conventional ventilation and with HFJV at I/E of 1:1 (18.9 ± 3.7 vs 18.0 ± 2.9) but decreased when I/E was reduced to 1:5 during HFJV (13.9 ± 2.1). The ratio of the product of Ca and Q̇ (systemic oxygen availability) to V̇ (ST/V̇) remained unchanged during all modes of ventilation (1.75 ± 0.15). The increase in Ca observed when I/E was reduced from 1:1 to 1:5 during HFJV was counterbalanced by a decrease in Q̇/V̇ such that ST/V̇ remained relatively constant. Pediatr Pulmonol 1987; 3:19–23.