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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During anesthesia, wheezing and difficult breathing are dangerous, requiring prompt therapy. The pressurized isoproterenol cartridge described in this report may be interposed conveniently in the anesthesia breathing system, is inexpensive, and provides accurate dosage. This device proved effective in treating bronchospasm and decreasing wheezing and secretions in 11 out of 12 cases. The mean (+/- SEM) peak airway pressure was 43 (+/- 2) torr before and 31 (+/- 2) torr after treatment; mean Paco2 was lowered from 60 (+/- 6) to 47 (+/- 4) torr; mean pH increased from 7.24 (+/- 0.03) to 7.33 (+/- 0.03), and mean percent increase in Pao2 was 32 (+/- 13.4). No cardiac arrhythmias, tachycardia, or rise in blood pressure were observed.
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PMID:Treatment of bronchospasm during anesthesia. 123 18

Asthma is associated with dysfunction of the beta-adrenergic receptor adenylyl cyclase signal transduction pathway. It has been argued that this results from receptor down-regulation by beta-agonist therapy. This study examined the relationship between nonspecific bronchial responsiveness (NSBR) to methacholine (Newcastle dosimeter method) and beta-adrenergic receptor density (Bmax) and affinity (%KH) in membranes from peripheral blood mononuclear leukocytes (MNL) in 12 male (27.3 +/- 1.7 yr old) and 14 female (31.4 +/- 1.7 yr old) drug-naive subjects with and without symptoms of mild intermittent wheezing. None had ever smoked or received any antiasthma medication. "Hyperresponsive" subjects were defined as those (n = 11) whose simplified slope of FEF50 (calculated as the percent fall in FEF50 divided by the dose of methacholine) was more than one SD above the mean for asymptomatic subjects. The log of the slope was reproducible (repeatability coefficient = 0.43) on two nonconsecutive days. Multiple regression analysis (overall R2 = 0.57) revealed negative relationships between the log of the slope and both Bmax (p = 0.016) and %KH (p = 0.011). Analysis of variance confirmed a lower mean (+/- SEM) value of %KH in "hyperresponsives" (45.7 +/- 5.5%) than in "normoresponsives" (60.4 +/- 4.1%, p = 0.04) with a similar trend for Bmax (hyperresponsives = 33.5 +/- 4.1 fmol/mg, normoresponsives = 45.9 +/- 7.1 fmol/mg, p = 0.18). These relationships between bronchial responsiveness, Bmax, and %KH cannot be explained by drug therapy, and they provide further evidence that there is an intrinsic impairment in the function of beta-adrenergic receptors on peripheral MNLs from subjects with high levels of nonspecific bronchial responsiveness.
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PMID:Relationship between nonspecific bronchial responsiveness to methacholine and peripheral mononuclear leukocyte beta-adrenergic receptor function in young drug-naive subjects. 132 48

Increased parasympathetic tone does not fully explain the night-time bronchoconstriction responsible for nocturnal cough and wheezing in asthmatic subjects. The overnight variation in function of the other neural pathway innervating bronchial smooth muscle--the non-adrenergic, non-cholinergic (NANC) system--was thus examined. NANC function was tested after parasympathetic and beta-adrenergic blockade in 12 normal subjects and 12 patients with mild asthma by comparing the bronchodilator effect (measured as oscillatory resistance, Ros) of capsaicin (an NANC stimulant) at 0400 h with that at 1600 h. The order in which capsaicin or diluent was given was randomised, and observers were blind as to which substance had been inhaled. Bronchodilatation was greater at 1600 h than at 0400 h in both the normal subjects (mean decrease in Ros 1-3 min after capsaicin at 1600 h 9% [SEM 1], at 0400 h -2% [1]; p less than 0.001) and the asthmatic group (1% [1], -7% [2]; p = 0.001). The results suggest that inhibition of NANC function in the early morning may contribute to overnight bronchoconstriction.
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PMID:Non-adrenergic, non-cholinergic nervous system and overnight airway calibre in asthmatic and normal subjects. 168 85

Noninvasive blood gas monitoring is a new, simple, and reliable method for assessing hyperreactivity associated with bronchial asthma. In this study, 104 atopic rhinitic subjects with no history of wheezing and 104 healthy volunteers were challenged with ultrasonically nebulized distilled water (UNDW). Blood gases were monitored transcutaneously (PtcO2 and PtcCO2) over 42 min (20 min for electrode stabilization, 3 min for monitoring a steady baseline, 5 min during UNDW, and 14 min after UNDW). Mean baseline PtcO2 and PtcCO2 values were comparable in the two groups. In rhinitic subjects only, a sudden decrease in PtcCO2 (starting immediately after the beginning of the challenge and maximal 34.7 +/- 0.4 mm Hg SEM versus baseline 41.8 +/- 0.2 SEM mm Hg at the third minute of UNDW exposure) was induced by the challenge and proved significant (p less than 0.001). In the same subjects, a slightly delayed decrease in PtcO2 (starting immediately after the end of UNDW inhalation and maximal 64.5 +/- 1.1 mm Hg SEM versus baseline 78.3 +/- 0.7 SEM mm Hg at 4 min post-UNDW) was also induced by the challenge and proved highly significant (p less than 0.001). The effects of UNDW inhalation on blood gases in normal subjects were negligible and nonsignificant. UNDW in nonasthmatic rhinitis but not in normal subjects gives rise to a sudden hyperventilation and to gas-exchange abnormalities presumably reflecting a ventilation-perfusion mismatching, which, however, is of shorter duration in rhinitic than in asthmatic subjects.
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PMID:Blood gas changes in nonasthmatic rhinitis during and after nonspecific airway challenge. 173 38

Methacholine challenges were performed in ten subjects with mild asthma at 2 h before and 20 min after placebo or 5, 10, 20, 40, 80, and 160 mg of inhaled verapamil given in a single-blind randomized crossover manner on different days. While verapamil did not have a bronchodilator effect, the 10-mg dose modestly increased the concentration of methacholine required to decrease FEV1 by 20 percent (PC20). The mean (+/- SEM) increase in PC20 from baseline was 2.1 +/- 0.2 times baseline after 10 mg of verapamil, compared to 1.1 +/- 0.1 times baseline after placebo (p less than 0.001). Unexpectedly, bronchoconstriction (greater than 10 percent decrease in FEV1) associated with cough or wheezing was observed in seven of ten subjects at doses of 20 mg or more. This adverse effect was not related to the osmolarity of the nebulized solutions. Thirty minutes before a standardized exercise challenge, 13 subjects inhaled placebo, 10 mg, or the highest dose of verapamil tolerated during the methacholine study (20 to 160 mg) in a double-blind randomized crossover manner. The exercise challenge was aborted in three subjects because of bronchospasm that occurred after administration of the higher dose. The mean (+/- SEM) maximum change in FEV1 after exercise in the ten subjects completing all three regimens of treatment was -17.1 +/- 4.0 percent after placebo, -12.7 +/- 4.3 percent after 10 mg (p less than 0.05), and -6.4 +/- 3.6 percent after the highest dose (p less than 0.05). We conclude that increasing the dose of verapamil above 10 mg did not provide greater benefit but, paradoxically, induced bronchoconstriction in most of the subjects. Because of this potential bronchoconstrictor effect, high doses of oral or intravenous verapamil should be used with caution in asthmatic subjects.
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PMID:Inhaled verapamil-induced bronchoconstriction in mild asthma. 206 Mar 39

Acute bronchiolitis (AB) is a common lung disease in infants manifested clinically by dyspnea and wheezing. The purpose of this study was to measure simultaneous plasma levels of histamine and a stable prostaglandin F2 alpha metabolite [13,14-dihydro-15-keto-PGF2 alpha (PG metabolite)], by radioenzymatic and radioimmunoassays, respectively, during and after recovery from AB. Blood was obtained from 15 infants during AB and from 14 and 9 of these infants when re-evaluated 6 and 18 months later, respectively. Mean (+/- 1 SEM) pre- and posttherapy (inhaled isoetharine) histamine levels (pg/ml), 1,923 +/- 980 and 1,035 +/- 250 during AB, respectively, were markedly higher than those of the same nonwheezing subjects at 18 months, 360 +/- 125, but unexpectedly lower than those at 6 months, 9,210 +/- 5,242. Of the 14 infants evaluated at 6 months, 7 had elevated histamine levels along with histories of recurrent wheezing after AB. Similarly, pre- and posttherapy PG metabolite levels (pg/ml), 1,033 +/- 419 and 1,613 +/- 527, respectively, were significantly higher than those of the same children when asymptomatic at 6 (27 +/- 7) and 18 months (68 +/- 25). Pre- and posttherapy levels of histamine and PG metabolite were higher than those of normal and sick, nonwheezing infants. These data indicate that histamine and PG metabolite are detectable in plasma during AB and suggest a role for histamine and PGF2 alpha in the pathogenesis of airways inflammation in AB.
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PMID:Plasma elevations of histamine and a prostaglandin metabolite in acute bronchiolitis. 238

Plasma concentrations of a stable prostaglandin F2 alpha metabolite were measured by radioimmunoassay during and after recovery from acute airway obstruction in 15 infants. Mean (SEM) metabolite concentrations (ng/l) in plasma obtained both before (1033 (418)) and after (1470 (413)) initial treatment for airway obstruction were significantly higher than those obtained from the same subjects after resolution of the obstruction--25.5 (6.6)--and those obtained from two comparison groups. Infants positive for respiratory syncytial virus (mean 1122 (227)) had significantly higher concentrations than those who were negative (207.6 (46)). Additionally, seven subjects with a history of recurrent wheezing after resolution of airway obstruction had a significantly higher mean level (3500 (1400)) during attacks of airway obstruction than those without (600 (100)). These data suggest that prostaglandin F2 alpha mediates respiratory inflammation in airway obstruction and that trials of specific anti-inflammatory agents for the treatment of airway obstruction may be warranted.
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PMID:Increases in plasma concentrations of a prostaglandin metabolite in acute airway obstruction. 235 3

Airway reactivity is known to increase in relation to the severity of asthma, and, in the community, hyperreactivity has been shown to be associated with respiratory symptoms such as wheezing and shortness of breath. However, the relation between change in airway reactivity and change in the severity of respiratory symptoms and change in the use of asthma medications within subjects has not been studied. We have investigated this relationship in a community population. In September 1984 and March 1985, the provocative dose of histamine producing a 20% fall in FEV1 (PD20) was measured, and respiratory symptoms and medication use assessed by questionnaire in 78 subjects taking part in a study of seasonal changes in airway reactivity. On both occasions, PD20 was negatively correlated with current frequency of wheezing, with the amount of asthma medication in regular use, and with the current general assessment of breathing problems. In the 45 subjects who had a PD20 value of 8 mumol or less on at least one of the two occasions tested, PD20 increased between September and March by 0.46 (SEM, 0.32) doubling doses of histamine (p = 0.16). Within subjects, change in PD20 was negatively correlated with change in the frequency of wheezing in the past month (p less than 0.005) and with change in medication use (p less than 0.05). This study demonstrates that PD20 is related to the severity of respiratory symptoms and medication use, and that change in airway reactivity within subjects in a community population is associated with changes in the frequency of wheezing and in the use of asthma medication.
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PMID:The relation between change in airway reactivity and change in respiratory symptoms and medication in a community study. 320 8

A survey was carried out in a steel foundry in Brisbane to evaluate the nature and frequency of respiratory symptoms and to assess ventilatory function. The foundry used many moulding processes including the Furane, Isocure, Shell, carbon dioxide, and oil sand systems. Nasal symptoms and wheeze were often reported, particularly by workers in the general foundry and core shop, and on a semiautomated line. By contrast, workers in the aftercast section not exposed to fumes or vapours from the various moulding processes reported these symptoms less often. Of 46 workers exposed to moulding fumes and vapours, 11 had developed a wheeze while working at the foundry. Wheeze and other respiratory tract symptoms were often attributed by the workers to exposure to substances at work, particularly from the Shell process which uses phenol formaldehyde resin and hexamethylenetetramine. Symptoms were reported also, but less often, on exposure to materials used in the Furane process (urea formaldehyde and furfuryl alcohol) and the Isocure process (methylene diphenyl diisocyanate, phenol formaldehyde, and dimethylethylamine). Ventilatory function studied over Monday and Friday showed a small and inconsistent changes. The six subjects working on the semiautomated line showed a small decrease in FEV1 (+/- SEM) (208 +/- 70 ml) only on Monday; this differed significantly from that in 17 aftercast workers (9 +/- 50 ml, p less than 0.05). Ventilatory function recorded before work on Monday morning showed no evidence of chronic airway obstruction in any group. Most environmental measurements were below the threshold limit values (TLV) except in the general foundry, where furfuryl alcohol was detected at concentrations of up to 50 ppm and formaldehyde at 4 ppm. The onset of symptoms in relation to exposure to various fumes and vapours suggests that both irritant and hypersensitivity mechanisms are present. As environmental modifications had occurred recently the apparent hypersensitivity may relate to past exposure levels above the TLV.
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PMID:Respiratory disease in foundry workers. 397 Aug 67

Multiple aspects of pulmonary mechanics were measured before and after bronchial challenges consisting of hyperpnea with cold air inhalation in 20 normal control subjects, 16 subjects with hay fever, and 44 asymptomatic asthmatics. These challenges had no effect on the lung function of the normal subjects. In the hay fever group, however, postchallenge mechanics changed a small, but significant, amount, e.g., mean decrease in forced expiratory volume in one second (FEV1) was -5.1 +/- 1.7% (SEM). The asthmatics had a much more marked response (mean fall in FEV1, -32.7 +/- 2.6%). There was considerable overlap between the responses of the normal subjects and those with hay fever, but no overlap at all between asthmatic and normal subjects. The only subjects with hay fever whose responses overlapped the asthmatic response were those who had histories of occasional episodes of wheezing. This pattern of response suggests that the use of hyperpnea and subfreezing air is a very sensitive and highly specific means of detecting increased air reactivity.
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PMID:Airway responsiveness to cold air and hyperpnea in normal subjects and in those with hay fever and asthma. 738 75


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