Atomic Structure of the Sb-Stabilized GaAs(100)-(2 x 4) Surface.
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Journal Article↗
Biomedical subjects
C Springer
Publications and source records attributed to C Springer.
[An unusual bronchial foreign body: a fragment of a tracheostomy tube].
A fragment of a fractured tracheostomy tube as a foreign body in the bronchus is very unusual. We report an 18-year old male with Hunter's syndrome who presented with fever and bronchorrhea. He had worn a tracheostomy tube for 2 years without its being removed for cleaning. Chest X-ray showed an opaque foreign body in the right main bronchus which was removed through a flexible bronchoscope and found to be a piece of the broken edge of the outer cannula of a tracheostomy tube. We suggest regular examination of tracheostomy tubes for signs of wear-and-tear and recommend their periodic renewal before they become worn out.
Adolescent↗
The transcriptional apparatus required for mRNA encoding genes in the yeast Saccharomyces cerevisiae emerges from a jigsaw puzzle of transcription factors.
The number of identified yeast factors involved in transcription has dramatically increased in recent years and the understanding of the interplay between the different factors has become more and more puzzling. Transcription initiation at the core promoter of mRNA encoding genes consisting of upstream, TATA and initiator elements requires an approximately ribosome-sized complex of more than 50 polypeptides. The recent identification and isolation of an RNA polymerase holoenzyme which seems to be preassembled before interacting with a promoter allowed a better understanding of the roles, assignments and interplays of the various constituents of the basal transcription machinery. Recruitment of this complex to the promoter is achieved by numerous interactions with a variety of DNA-bound proteins. These interactions can be direct or mediated by additional adaptor proteins. Other proteins negatively affect transcription by interrupting the recruitment process through protein-protein or protein-DNA interactions. Some basic features of cis-acting elements, the transcriptional apparatus and various trans-acting factors involved in the initiation of mRNA synthesis in yeast are summarized.
Biological Evolution↗
Comparison of respiratory inductance plethysmography with thoracoabdominal compression in bronchial challenges in infants and young children.
Respiratory inductance plethysmography measuring thoracoabdominal asynchrony (TAA) has been claimed to be a useful tool for measuring changes in airway resistance in infants. In this study we evaluated the response to methacholine by thoracoabdominal compression and respiratory inductance plethysmography. Seventeen infants (mean age, 13.1 +/- 4.7 mo) with recurrent episodes of cough or wheeze underwent bronchial challenge with inhaled methacholine. Lung function was evaluated by measuring maximal expiratory flow at resting lung volume (VmaxFRC), and the degree of TAA was measured by phase angle (theta). Methacholine was inhaled for 1 min during tidal breathing using increasing doubling concentrations until a fall of at least 40% in VmaxFRC was achieved (final concentration). All infants responded to the final concentration of methacholine by a significant fall in VmaxFRC (from 31 +/- 10 to 12 +/- 5 ml/s/kg, p < 0.001). All but one infant responded to methacholine at the final concentration with a significant increase in phase angle (median theta increased from 11.7 to 31.7 degrees, p < 0.001). In two other infants there was an early response in theta compared with the response in VmaxFRC. Phase angle increase after methacholine was expressed as Z-scores (the difference between postmethacholine theta and postbuffer theta divided by the standard deviation of postbuffer theta). An increase of at least 2.0 Z-scores in theta was observed at the same concentration of methacholine when VmaxFRC fell by at least 40% in 15 of the 17 infants (88%). We conclude that respiratory inductance plethysmography is a sensitive method to measure bronchial reactivity to methacholine in most of the infants studied (14 of 17, 82%). A concentration of methacholine causing an increase in theta of at least 2.0 standard deviations above baseline is equivalent to the concentration causing a 40% fall in VmaxFRC.
Airway Resistance↗
Home recording of PEF in young asthmatics: does it contribute to management?
The value of home monitoring of peak expiratory flow (PEF) as part of an action plan for asthma management in children and young adults is uncertain. We sought to determine whether home recording of PEF benefited asthma management and whether any contribution was affected by the severity of the asthma. Twenty-eight children and young adults with asthma of different severity (mean age 14 yrs; 95% confidence interval (95% CI) 12-16 yrs) recorded their symptoms, drug consumption and PEF twice daily for a mean of 82 days over a 12 week period, and attended the laboratory every 2 weeks for measurement of lung function. The number of individual patients with significant correlations for laboratory lung function tests compared with ambulatory PEF and diary scores averaged over the preceeding 2 weeks was low in all severity groups. When measured in the laboratory, PEF meter readings correlated poorly with PEF measured by spirometry. The proportion of patients with significant correlations for PEF, symptoms and rescue bronchodilator use on a day-to-day basis was 70-80% in the group of severe asthmatics and significantly less in the mild asthmatics. In a subgroup of 14 patients who were sick on a mean of 19 days, the mean difference in PEF between well and sick days was 14% of predicted. Diurnal PEF variation correlated poorly with other parameters in all groups. It is concluded that PEF monitoring adds little to daily recording of symptoms and bronchodilator use in the management of young patients with severe asthma, and it is too insensitive to register meaningful clinical changes in those with milder asthma.
Adolescent↗
Advances in physiological chemistry by in vivo NMR. A workshop sponsored by the Society of Magnetic Resonance held in Woods Hole, Massachusetts.
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Animals↗
Sensitivity and specificity of oropharyngeal suction versus bronchoalveolar lavage in identifying respiratory tract pathogens in children with chronic pulmonary infection.
The purpose of this study was to compare the pathogens obtained by oropharyngeal suction (OPS) and bronchoalveolar lavage (BAL) in children with chronic pulmonary infections. Forty-four children (mean age of 6.1 years; range 4 months to 15 years) were included in the study (27 children with recurrent localized lung infection, 5 with bronchiectasis, 5 with cystic fibrosis, 2 with foreign body aspiration, 2 with bronchiolitis obliterans, and 3 with recurrent episodes of cough and shortness of breath). In 27 out of 44 BAL samples (61%) bacterial cultures were positive. The sensitivity of OPS in detecting the same BAL pathogen was 89% (24/27 samples), the specificity was 94% (16/17 samples), and the predictive value was 91% (40/44 samples). Hemophilus influenzae beta-lactamase negative was the main organism recovered from BAL in non-cystic fibrosis patients with recurrent or persistent pneumonia. We conclude that OPS is a simple and efficient noninvasive procedure which may be helpful in the diagnosis and treatment of recurrent or chronic pulmonary infection.
Bacterial Infections↗
Comparison of adenosine 5'-monophosphate and methacholine for the differentiation of asthma from chronic airway diseases with the use of the auscultative method in very young children.
Methacholine and adenosine 5'-monophosphate bronchial challenges were performed in 54 young children--39 with asthma and 15 with other chronic airway diseases (CADs), with the use of the auscultative method. Children with asthma were sensitive to both methacholine and adenosine; children with CAD responded only to methacholine. We conclude that bronchial challenge with adenosine can help differentiate asthma from CAD in young children.
Adenosine Monophosphate↗
Activation and repression of the yeast ARO3 gene by global transcription factors.
The ARO3 gene of Saccharomyces cerevisiae codes for the phenylalanine-inhibited 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase (EC 4.1.2.15) and is regulated by the general control system of amino acid biosynthesis through a single GCN4-binding site in its promoter. A combined deletion and mutation analysis of the ARO3 promoter region in a delta gcn4-background revealed two additional regulatory systems involved in ARO3 transcription. The ARO3 gene is (i) activated through a sequence element which binds the multifunctional DNA-binding protein ABF1 in vitro and (ii) repressed through an URS1 element, which binds the same protein in vitro as the URS1 element in the CAR1 promoter. Since both the ABF1-binding site and the URS1 element represent cis-acting elements of global transcription regulatory systems in yeast, the ARO3 gene is the first example of a GCN4-regulated gene which is both activated and repressed by global transcription factors. Activation of the ARO3 gene through the ABF1-binding site and repression through the URS1 element seem to be independent of each other and independent of activation by the GCN4 protein.
Arginase↗
A complex unidirectional signal element mediates GCN4 mRNA 3' end formation in Saccharomyces cerevisiae.
The yeast GCN4 3' element represents a class of polyadenylation sites which function unidirectionally and efficiently in test systems in vivo as well as in vitro. A complex signal element is required for polyadenylation activity with a minimal size of 116 nucleotides for the functional element. We subdivided this element into five regions (EL1 to EL5) of 16 to 26 nucleotides each. Each region was characterized by deletion analysis in an in vivo test system. Two TTTTTAT motifs are located in different regions (EL1 and EL4) upstream of the poly(A) site. The 3' end processing activity was significantly reduced when both motifs were mutated by site-directed mutagenesis and abolished when EL1 and EL4 were deleted. The major poly(A) site is located in EL5, 3 nucleotides downstream of the second TTTTTAT motif. Additional minor poly(A) sites are used in less than 10% of the mRNA 3' ends. Deletion of EL3 resulted in a changed pattern of mRNA 3' ends by increased usage of the minor poly(A) addition sites. The major poly(A) site in EL5 can be removed without loss of function when sequences upstream of EL1 are present. The tripartite TAG...TATGT...TTT sequence located downstream of EL5 is not required for function.
Base Sequence↗
Adenosine, methacholine, and exercise challenges in children with asthma or paediatric chronic obstructive pulmonary disease.
BACKGROUND: Bronchial hyperreactivity to methacholine is present in children with asthma and other types of paediatric chronic obstructive pulmonary disease (COPD), while hyperreactivity to exercise is more specific for asthma. Adenosine 5'-monophosphate (AMP) is a potent bronchoconstrictor and, like exercise, may provoke asthma by activating mast cells. This study investigated the suitability of AMP as a specific challenge for asthma in children. METHODS: Bronchial provocation challenges with methacholine and AMP were performed in a double blind fashion using tidal breathing in 51 children with asthma, 21 with paediatric COPD of various types, and in 19 control children. Each subject also underwent a standardised exercise challenge after inhalation challenges were completed. Sensitivity and specificity curves were constructed and the intersection point of sensitivity and specificity for each type of challenge was determined. RESULTS: When the asthmatic patients were compared with the children with COPD, the intersection points for AMP, exercise and methacholine were 90%, 85%, and 50%, respectively. When compared with the controls the same intersection points were 98%, 84%, and 92%, and when children with paediatric COPD were compared with controls they were 55%, 50%, and 82%. CONCLUSIONS: Methacholine distinguishes both asthma and paediatric COPD from controls with a sensitivity of 82-92%, but does not distinguish between asthma and paediatric COPD; exercise and AMP distinguish asthma from controls with a sensitivity and specificity of 84-98% but they also distinguish asthma from paediatric COPD with a sensitivity and specificity of 85-90%. AMP inhalation is a practical aid for diagnosing asthma and distinguishing it from COPD in children of all ages.
Adenosine Monophosphate↗
The safety of air transportation of patients with advanced lung disease. Experience with 21 patients requiring lung transplantation or pulmonary thromboendarterectomy.
Air travel can cause severe respiratory decompensation in a patient with advanced lung disease due to high altitude hypoxemia. We report our experience in flying 21 patients with advanced lung disease to a medical center remote from Israel for lung transplantation or pulmonary thromboendarterectomy (PTE). All patients had severe lung disease with marked hypoxemia (PaO2, 40 to 59) and 16 had significant pulmonary hypertension. Nine patients (with emphysema and pulmonary fibrosis) required single lung transplant, four (with cystic fibrosis and emphysema) required double-lung transplant, six (with primary or secondary pulmonary hypertension) required heart-lung transplant, and two (with major vessel pulmonary thrombosis) required PTE. All patients were flown by commercial aircraft to centers located 2,634 to 13,181 km away from Israel. Length of flight was between 4 and 21 h. Patients were given oxygen supplementation during the flight and were monitored by portable oximeters. All but three patients were hemodynamically stable and 19 of them were escorted by physicians. All but one hemodynamically unstable patient who died on board arrived safely at their destinations. We conclude that with careful preparation, sufficient oxygen supply, oximetric monitoring, and medical escort, almost any patient with severe lung disease can travel by air to any necessary destination.
Adult↗
Effect of natural oxygen enrichment at low altitude on oxygen-dependent patients with end-stage lung disease.
OBJECTIVE: To assess the effect of lowering altitude to that of the lowest place on earth (Dead Sea) on arterial oxygenation and exercise performance in patients with hypoxemia and end-stage lung disease. DESIGN: A cohort of 10 patients. SETTING: Pulmonary function laboratories in Jerusalem, Israel, and at the Dead Sea. PATIENTS: 10 patients with end-stage lung disease who were receiving long-term oxygen therapy. The 4 males and 6 females were 12 to 77 years old. Four patients had chronic obstructive pulmonary disease; 2 had cystic fibrosis; 3 had pulmonary fibrosis; and 1 had pulmonary hypertension (thromboembolic). Mean forced vital capacity was 1.54 L (54% of predicted value) and mean forced expiratory volume in 1 second was 0.85 L (35% of predicted value). MEASUREMENTS: Spirometry, blood gas analysis, progressive exercise testing, and sleep oximetry were done in Jerusalem (altitude, 800 m above sea level; barometric pressure, 696 mm Hg); the same measurements were done 6 days after arrival at the Dead Sea (altitude, 402 m below sea level; barometric pressure, 800 mm Hg) and then 7 to 14 days later in Jerusalem. RESULTS: Arterial oxygenation increased from a median partial pressure of arterial oxygen of 51.6 mm Hg in Jerusalem to 67.0 mm Hg at the Dead Sea, an increase of 15.2 mm Hg (95% CI of paired difference, 4.1 to 20.4 mm Hg; P = 0.001). Partial pressure of arterial carbon dioxide increased from a median of 43.2 to 45.9 mm Hg, an increase of 2.7 mm Hg (CI, 0.5 to 6.4 mm Hg; P = 0.004), with a borderline significant change in the alveolar-arterial gradient. Arterial oxygen saturation increased from a median of 87.7% to 92.8%, a change of 4.8% (CI, 1.9% to 9.8%; P = 0.003). Exercise performance also improved as maximum oxygen uptake increased from a median of 827 mL/min to 1056 mL/min, an increase of 203 mL/min (CI, 54 to 388 mL/min; P = 0.006). Sleep oximetry also improved as median arterial oxygen saturation measured during sleep increased from 85% to 90%, a change of 5% (CI, 2% to 7%; P = 0.005), and percentage of sleep time with an oxygen saturation rate of 90% or more increased from a median of 24% to 73%, a change of 49% (CI, 20% to 87%; P = 0.02). No change in spirometry was noted. All patients felt less dyspneic and reported improved functional capacity with reduced need for oxygen. CONCLUSION: Descent to low altitude can improve arterial oxygenation, exercise performance, and sleep oximetry and consequently the quality of life in patients with hypoxemia and advanced lung disease.
Adolescent↗
Tracheoesophageal fistula induced by aspergillus infection following bone marrow transplantation.
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Aspergillosis↗
Protective effect of albuterol delivered via a spacer device (Babyhaler) against methacholine induced bronchoconstriction in young wheezy children.
Nine young asthmatic children aged 2-5 years underwent methacholine challenge after placebo or albuterol administered by metered dose inhaler through a spacer device (Babyhaler) with a face mask in a double-blind, cross-over, randomized study. The methacholine challenge was performed using chest auscultation to define the provocative concentration of methacholine that causes wheezing (PCW). The PCW increased from a geometric mean of 0.28 mg/mL after placebo to 3.59 mg/mL after albuterol (P < 0.0001). The protective effect of albuterol against methacholine-induced bronchospasm was 3.7 +/- 1.2 doubling doses. We conclude that administration of drugs from a metered dose inhaler through the Babyhaler with a face mask is effective. Albuterol causes a major reduction in the bronchial hyperreactivity in young wheezy children shortly after administration.
Albuterol↗
Assessment of the ability of young children to use a powder inhaler device (Turbuhaler).
The purpose of the study was to determine the age at which young asthmatic children could master the use of a new powder inhaler device (Turbuhaler). We studied 59 children with asthma between the ages of 3 and 6 years who consecutively attended the asthma clinic of the pediatric department. Efficiency of inhalation and the pharmacological effect of the terbutaline in the inhaler were measured by scores for inhalation technique and clinical response. None of the 3-year-old children used the device efficiently, but 43% of the 4-year-old, 67% of the 5-year-old, and 80% of the 6-year-old children used the inhaler correctly. Although inhaler technique was not perfect in the younger age group, 50% of the 3-year-old children demonstrated clinical improvement of asthma symptoms after inhalation. In the older age groups, 79%, 92%, and 100% of the 4, 5, and 6-year-old children demonstrated clinical improvement of asthma symptoms after inhalation. It is concluded that the new mode of dry powder delivery system (Bricanyl Turbuhaler) can be used in young asthmatic children who are 4 years of age and above.
Age Factors↗
Recurrent cyanotic spells caused by a segmental intramural cyst of the upper trachea.
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Bronchogenic Cyst↗
Chloroquine treatment of interstitial lung disease in children.
Seven children aged 3 months to 11 years with histologically confirmed interstitial lung disease (ILD) [6 with desquamative interstitial pneumonitis (DIP) and 1 with chronic interstitial pneumonitis] were treated with chloroquine, 10 mg/kg/day. One patient, diagnosed late in the course of the disease, died after three weeks of treatment, despite the addition of systemic corticosteroids. Another patient responded to combined therapy with chloroquine and prednisone and had a normal lung biopsy after 6 months of treatment. He underwent surgical repair of mitral valve stenosis and died after extensive brain infarction. The other 5 patients responded well to chloroquine therapy with major improvement in oxygenation within a few weeks and in lung function over the next few months. They remained well clinically and physiologically, including a normal response to incremental exercise, during a mean follow-up period of 9.8 years (range 3.5 to 15.7 years). None of the patients has developed retinopathy or any other ocular complication. Bronchoalveolar lavage was a useful tool for evaluation of the activity of the disease (predominance of neutrophils) in 3 out of 4 patients. We suggest that chloroquine should be considered as an effective treatment in ILD in children. Incremental exercise test may be helpful for routine follow-up and evaluation of the efficacy of a specific treatment.
Child↗