Emergency management of the child with asthma.
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Asthma↗
Biomedical subjects
B K Rubin
Publications and source records attributed to B K Rubin.
Mucus-depleted frog palate as a model for the study of mucociliary clearance.
To better understand the frog palate model of mucociliary transport, we measured the transport rate of mucus (MTR) from the leopard frog, Rana pipiens, and from the bullfrog, R. catesbeiana, recorded the stability of the MTR over a period of hours and days and over the course of 1 yr, and measured the viscoelasticity, percent solid composition, and spinnability (filance) of mucus from both species. Bullfrog mucus was less rigid than leopard frog mucus (log G* at 1 rad/s 2.09 vs. 2.61; P less than 0.01) and had a higher viscosity-to-elasticity ratio (tan delta at 1 rad/s 0.36 vs. 0.26; P less than 0.05). It also had a lower solids content (8.71 vs. 13.72%; P = 0.02), and there was a trend to lower spinnability for bullfrog mucus (filance 26.7 vs. 33.5 mm). These data suggest that bullfrog mucus has viscoelastic properties similar to normal mammalian respiratory mucus and leopard frog mucus has viscoelasticity similar to sputum samples. MTR was significantly slower in the winter than in the summer months (17 vs. 30 mm/min; P less than 0.0001). Although the leopard frog palate could be used for at least 7 consecutive days without exhaustion, bullfrog palates could be used for only 5 days. Palates of either species could generally be tested for 6 h/day without a significant decrease in MTR. These data clarify some of the sources of variability in the use of this system and suggest methods of standardization.
Animals↗
Collection and analysis of respiratory mucus from subjects without lung disease.
We collected the respiratory mucus coating the endotracheal tubes used during short surgical procedures in 27 patients with no clinical evidence of respiratory disease. Twelve were male and 15 were female, and they ranged from 1 to 64 yr of age (mean, 28.7 yr). The viscoelastic properties, frog palate transport rate, and percent solid composition were in the normal range reported for both canine and human mucus collected using the bronchoscopy brush technique. There were no significant differences noted between male and female patients, and there were no changes in mucus or transport properties seen with aging. Mucus was also collected separately from the inside of the tube exposed to constant gas flow (13 patients), and from the outside of the endotracheal tubes in 25 patients. Although there were no significant differences in viscoelastic properties between inside and outside mucus, there was a greater thread formation (filance, 45 versus 26 mm; p less than 0.005) and a higher percentage of solids in mucus from the inside of the endotracheal tube (15.9 versus 11.4%; p less than 0.05), which is compatible with reduced hydration. The duration of anesthesia ranged from 25 to 195 min (mean, 85 min). There was no effect of duration of anesthesia on any of the measured mucus properties. This technique for mucus collection allows us to study alterations in mucus properties in patients with and without pulmonary disease at the time of incidental surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
The Mexican asthma cure. Systemic steroids for gullible gringos.
Asthmatic patients from western Canada and the United States have reported that after visits to an asthma clinic in Mexicali, Mexico, they return home substantially improved or cured having received "a bronchodilator medication unavailable in the United States or Canada because of the big drug companies." Analysis of these medications reveals that the most commonly prescribed combination is the glucocorticoid triamcinolone (unscored white tablets) and the antihistamine chlorpheniramine (coated biconvex orange or red tablets). Occasionally benzodiazepines are added to these medications. The patients are assured that the medications which they have been given are free of side effects and specifically, that corticosteroids are not used. Such therapy is dangerous to the patient who not only is unaware of the medications that he or she is taking, but is unlikely to mention this therapy to his or her physician. These patients risk drug interactions, medication side effects, and the possibility of adrenal failure either with a stress to their system or on withdrawal of drug treatment. Patients are also at risk of abandoning safer forms of asthma therapy for the miracle cure. We, too, are partially responsible for these unethical practices by avoiding the use of steroids and undertreating our patients at times, leaving them unnecessarily restricted and eager for any form of relief.
Asthma↗
General anesthesia does not alter the viscoelastic or transport properties of human respiratory mucus.
Observations that mucus transport rates (MTR) are depressed in anesthetized animals and humans have led to speculation that general anesthesia depresses ciliary activity or adversely alters the physical properties of the respiratory mucus (RM). We investigated the possibility that anesthesia changes the physical properties of RM in such a way as to depress ciliary transport. We collected 33 samples of RM from the endotracheal tubes (ETTs) of 25 people aged 1 to 79 years undergoing elective surgery who had no clinical evidence of lung disease. We measured the rigidity, viscoelasticity, spinnability, and the percentage of solid composition of these specimens as well as the transport of the collected RM across the mucus-depleted frog palate. These physical properties were not significantly different from RM collected from awake volunteers using the bronchoscopy brush collection technique. Differences in spinnability, transportability, and solid content of paired mucus samples from the inside and outside of the ETTs are suggestive of altered RM hydration, but this requires further study. The decrease in MTR during general anesthesia is probably due to mechanisms other than alterations in the physical properties of mucus.
Adolescent↗
Mucus transport in a miniaturized simulated cough machine: effect of constriction and serous layer simulant.
The transport of mucus gel simulant (MGS) in a constricted simulated cough machine, using blood plasma as a serous layer simulant (SLS), was investigated. MGS was prepared from locust bean gum solutions crosslinked with varying amounts of added borate to produce gels of varying spinnability (filance). The model trachea was a plexiglass channel of rectangular cross-section with the plane bottom surface. The upper surface included a sinusoidal protrusion which provided a flow convergence with minimum gaps of 6, 4 and 2 mm. Experiments for mucus transport were conducted for these minimum gaps, as well as for the non-convergent case (12 mm gap). Miniaturization of sample quantity was achieved by keeping the MGS layer depth constant (0.5 or 1 mm) but reducing the zone of loading from 13.4 cm to 1 cm, thus reducing the sample requirement to as little as 0.2 ml. MGS transport was determined as the minimum displacement of a line of marker dye placed in the MGS layer at the point of minimum constriction gap. It was shown that in all cases (dry as well as with SLS), MGS transport increased as the minimum constriction gap between the plane and the convergent top surface decreased. This increase was further enhanced if an SLS of lesser viscosity was used. It was also found that the transport of MGS increased as the depth of MGS layer increased or as the filance decreased in both non-constricted and constricted cases. The relationship between MGS transport and filance was maintained even in the presence of an SLS layer.
Airway Obstruction↗
Immotile cilia syndrome (primary ciliary dyskinesia) and inflammatory lung disease.
Abnormal mucociliary clearance can either be due to defects of mucus production and rheology or to abnormalities of the cilia. Ciliary dysfunction can be inherited as a genetically determined defect in axonemal structure (called the immotile cilia syndrome or primary ciliary dyskinesia) or acquired defects can result from airway injury. This article examines the defense of the lung as related to ciliary activity and addresses ways in which this activity can be modified by inflammatory mechanisms.
Cilia↗
Myelodysplasia and the Arnold-Chiari malformation.
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Arnold-Chiari Malformation↗
An alternate technique to determine umbilical arterial catheter length.
Sick babies often have an umbilical artery catheter (UAC) inserted. To minimize risk to the baby, the catheter is inserted a distance calculated to place it either between the third and fifth lumbar vertebrae or between the sixth and 10th thoracic vertebrae when checked radiographically. The methods used to calculate this insertion distance require that length measurements of the baby be plotted on reference graphs. Directly measuring the distance from the baby's xiphoid process to his pubis and adding this to the distance from the pubis to mid-umbilicus yields an UAC insertion length that places the catheter between T6 and T10 as accurately as methods that require reference charts.
Body Height↗
The management of anaesthesia for patients with cystic fibrosis.
The clinical problems of patients with cystic fibrosis who require anaesthesia are reviewed. The management and the complications of anaesthesia in 77 patients over a 3-year period are presented. The long term effects of anaesthesia are analysed by a study of the lung function tests of these patients. The results suggest that even multiple procedures, as for instance nasal polypectomy, are not harmful. A method for safe peroperative management is presented.
Adolescent↗
Modification of Welch-Allyn "11500 ophthalmoscope for visuoscopy.
Visuoscopy is an indispensable test in the evaluation of the monocular fixation pattern. Unfortunately, the instrumentation needed to accurately perform the test is often costly. A procedure describing how the Welch-Allyn "11500 ophthalmoscope may be inexpensively modified for the routine performance of visuoscopy is presented.
Fixation, Ocular↗
"Cephalomalacia obfuscate," a fourth generation cephalosporin.
A new fourth generation cephalosporin, cephalomalacia obfuscate, has been synthesized. Limited testing has shown this new class of antibiotic to have substantially greater bacteriopathic properties than the third generation antibiotics. The role that these properties may play in host defense is discussed.
Cephalosporins↗
The evaluation of the child with recurrent chest infections.
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Airway Obstruction↗
Transfer of Typhimurium from tigers to a toddler.
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Adult↗
Bronchial mucus properties in lung cancer: relationship with site of lesion.
OBJECTIVE: To compare the biophysical properties of mucus from the left and right mainstem bronchi in patients undergoing diagnostic bronchoscopy because of a unilateral radiological abnormality. It was hypothesized that abnormalities in the properties of mucus would be greater on the side with the lesion and that this would be most obvious in patients with unilateral lung cancer. PATIENTS AND METHODS: Bilateral paired samples of bronchial mucus were taken from 38 nonatopic patients (aged 59.8+/-12.6 years) including 16 nonsmokers, 14 current smokers and eight exsmokers (more than one year). Twenty of the 38 patients had a radiologically defined unilateral abnormality. Eight of these 20, including one nonsmoker, had lung cancer. The viscoelastic properties of the collected mucus were determined by magnetic microrheometry, and the analysis was carried out without knowledge of the histological diagnosis or source. RESULTS: The rheological properties of mucus strongly suggested which was the abnormal side. Within the group of 20 patients with a unilateral radiological abnormality, mucus from the side of the lesion had a lower value of the loss tangent, tan d100 (P=0.004), indicating greater mucus recoil. This is consistent with poor mucus cough clearability on the lesion side. All eight cancer patients fit this mucus rheological pattern with a lower value of tan d100 on the affected side (P=0.007). Four of the five other patients with a similar mucus abnormality were categorized as high cancer risk by other criteria, while six of seven patients with mucus that did not have this abnormality were considered to be lower risk. Based on the mucus analysis done at the time of the bronchoscopy, two of the 'noncancer' patients initially designated as high risk had cancer detected after several months of follow- up. Only two of the 18 patients without a defined unilateral lesion fit the mucus 'cancer pattern'. CONCLUSIONS: These findings are consistent with the hypothesis that either abnormalities in mucus properties may represent a risk factor for the development of lung cancer or that bronchial mucus abnormalities may be associated with products secreted by the tumours that, in turn, may suppress mucus clearance.
Adult↗
PCR detection of viral nucleic acid in fatal asthma: is the lower respiratory tract a reservoir for common viruses?
BACKGROUND: There is indirect evidence implicating viral respiratory tract infections in the pathogenesis of fatal asthma. However, it is unknown whether viruses are present within the lower respiratory tract in fatal asthma. OBJECTIVES: To apply a nine-virus polymerase chain reaction (PCR) panel to postmortem specimens of lower airway secretions and compare the prevalence of viral nucleic acid among patients who died of asthma, asthmatic patients who died of other causes and persons who died without lung disease. PATIENTS AND METHODS: Postmortem specimens of lower airway secretions from patients who died of asthma (fatal asthma [n=10]), asthmatic patients who died of other causes (n=4) and nonasthma controls (n=6) underwent PCR for nine common respiratory viruses. The prevalence of each virus was compared among the three groups. RESULTS: PCR was positive for at least one virus in 19 of 20 cases, and multiple viruses were detected in 14 of 20 cases. The prevalence of each virus was similar in the three groups studied. CONCLUSIONS: In fatal asthma, lower airway secretions do not show a specific pattern of viral nucleic acid. Intriguingly, these results suggest that the lower respiratory tract may act as a potential reservoir for common respiratory viruses.
Adenoviridae↗