Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BRONCHUS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1983

Effect of hypothermia on beta 1-adrenoceptor-mediated relaxation of pig bronchus.

The relaxant potencies of (+/-)-isoprenaline and of (-)-noradrenaline (NA) in the pig isolated bronchus were increased 5.4 and 3.1 fold respectively by lowering the organ bath temperature from 37 degrees C to 27 degrees C, whereas the potencies of the non-catecholamine beta-adrenoceptor agonists fenoterol and orciprenaline were not significantly changed. At 37 degrees C, the catechol-O-methyl transferase (COMT) inhibitor U-0521 (30 microM), caused a 7.2 fold increase in the potency of isoprenaline but had no effect on the potency of fenoterol. At 27 degrees C the potency of isoprenaline was similar in the absence or presence of U-0521 (30 microM). Furthermore, in bronchi where extraneuronal uptake was inhibited by phenoxybenzamine, the potency of NA was not significantly altered by reducing bathing temperature from 37 degrees C to 27 degrees C. These results suggest that the hypothermic potentiation of isoprenaline in pig bronchus resulted from inhibition of COMT or of access to COMT, rather than from sensitization of beta 1-adrenoceptors.

Adrenergic beta-Agonists↗
PubMed1983

Classification of beta-adrenoceptors in isolated bronchus of the pig.

1 (+/-)-Isoprenaline (Iso), (-)-adrenaline (Ad), (-)-noradrenaline (NA), the beta 2-selective adrenoceptor agonist (+/-)-fenoterol (Fen) and the beta 1-selective adrenoceptor agonist (+/-)-RO363 caused concentration-dependent relaxation of preparations of pig bronchus pre-contracted with carbachol 40-ng/ml (0.22 microM). Iso, Ad, NA and Fen caused complete relaxation of carbachol-induced tone, but RO363 caused relaxation equivalent to only 59% of the maximal response to Iso. 2 When relaxation responses to these amines were plotted as a % of their maximal effects, comparison of EC50 values showed that the order of potency was RO363 greater than Iso greater than NA greater than Fen greater than Ad (14.4:4.6:1:0.4:0.3). 3 pA2 values determined for the beta-adrenoceptor antagonists propranolol (non-selective) and atenolol (beta 1-selective), or the partial agonist salbutamol (beta 2-selective) using Iso as agonist were 8.3, 7.3 and 4.4 respectively. The pA2 value for atenolol using RO363 as the agonist was 7.6. 4 These results indicate that porcine bronchus contains a homogeneous population of beta 1-adrenoceptors.

Animals↗
PubMed1992

Effects of BRL 38227 on neurally-mediated responses in the guinea-pig isolated bronchus.

1. In guinea-pig isolated bronchus treated with indomethacin (2.8 microM), electrical field stimulation (EFS; 10 Hz, 0.5 ms, 60-70 V, for 10 s) evoked a tetrodotoxin (3 microM)-sensitive, biphasic contraction comprising a rapid, atropine (1 microM)-sensitive cholinergic response succeeded by a slowly developing, capsaicin (10 microM)-sensitive, non-adrenergic, non-cholinergic excitatory (NANCe) response. 2. BRL 38227 (0.3-3 microM), salmeterol (0.003-3 microM) and ketotifen (1.0-300 microM) each produced concentration-dependent inhibition of both NANCe and cholinergic responses to EFS in guinea-pig isolated bronchus. 3. Substance P (SP; 1 microM) and neurokinin A (NKA; 0.07 microM) produced contractions equivalent in magnitude to the NANCe response to EFS, which were inhibited by salmeterol (1 microM), but not by BRL 38227 (3 microM) or ketotifen (100 microM). 4. Acetylcholine (ACh; 6 microM) was equi-effective with the electrical activation of cholinergic neurones. BRL 38227 (3 microM) slightly inhibited responses to ACh (6 microM). Salmeterol (1 microM) and ketotifen (100 microM) markedly inhibited responses to ACh (6 microM). 5. In bronchial rings pre-contracted with ACh (100 microM), BRL 38227 (0.1-30 microM), salmeterol (0.001-3 microM) and ketotifen (0.1-100 microM) each produced concentration-dependent relaxation. Unlike ketotifen, BRL 38227 and salmeterol only partially (18.8 +/- 2.1% and 51.8 +/- 3.9% respectively) reversed the ACh-induced contraction. 6. The (+)-analogue of BRL 38227, BRL 38226 (0.3-100 microM), was without effect on responses to EFS and had no effect on the inhibition caused by BRL 38227. The K+-channel activators pinacidil (3.0-30 microM) and RP 52891 (3.0-30 microM) exerted similar inhibitory actions on responses to EFS as BRL 38227, but were less potent. Glibenclamide (0.1-1.O microM) and phentolamine (3 microM) antagonized the inhibitory effects of BRL 38227 on responses to EFS.7. It is concluded that BRL 38227 and ketotifen can inhibit NANCe neuroeffector transmission at concentrations exerting little or no inhibitory effects on responses to exogenously applied tachykinins.By contrast, in addition to suppressing NANCe responses to EFS, salmeterol also markedly inhibits responses to SP and NKA. At concentrations markedly suppressing cholinergic neuroeffector transmission, BRL 38227 has only minor effects on responses to exogenously-applied ACh. Salmeterol and ketotifen both depress responses to ACh within the concentration-range over which they inhibit cholinergic responses to EFS. The inhibitory effects of BRL 38227 on responses to EFS exhibit stereo-specificity and may involve the opening of a neuronal K+-channel. This K+-channel is glibenclamide-and phentolamine-sensitive and appears similar to the smooth muscle K+-channel which is modulated by BRL 38227.

Albuterol↗
PubMed1992

Contractile activity of big endothelin-1 on the human isolated bronchus.

1. We have studied the contractile activity of the 39 amino acid precursor of endothelin-1 (ET-1), big endothelin-1 (big ET-1), on human isolated bronchi. The contribution of the metalloproteases, neutral endopeptidase (NEP) and angiotensin converting enzyme (ACE), in the presence or absence of the epithelium lining, by use of specific inhibitors, was also evaluated on the effects of big ET-1. 2. Big ET-1 elicited a potent contraction of human isolated bronchus. The -log EC50 value for big ET-1 was 7.53 +/- 0.08 (n = 11) and Emax 78.5 +/- 3.8% (% of ACh 3mM). 3. Incubation of human isolated bronchi with the NEP inhibitor phosphoramidon (10(-5) M) induced a rightward shift of the concentration-response curve induced by big ET-1 (10(-9) M to 3 x 10(-7) M). Similar results were observed when human bronchi were incubated with thiorphan (10(-5) M), but the shift to the right was significantly less (P less than 0.01) than that observed in the case of phosphoramidon (-0.35 +/- 0.05 vs -0.67 +/- 0.07 log unit). 4. The two inhibitors of angiotensin I converting enzyme (ACE), captopril or enalapril diacid, did not affect the concentration-response curve for contraction induced by big ET-1. 5. When the epithelium was removed, a leftward shift of the concentration-response curve of big ET-1 (10(-9) M to 3 x 10(-7) M) was observed. Incubation of human isolated bronchi with phosphoramidon or thiorphan (10-5M) or with enalapril diacid or captopril did not modify the leftward shift of the concentration-response curve for big ET-1 after epithelium removal.6. These results suggest that big ET-1 elicits potent contractile activity in the human isolated bronchus and that its effect is the consequence of the conversion to ET-1 by a phosphoramidon-sensitive metalloprotease which, although different from NEP and ACE, appears to be similar to the endothelinconverting enzyme (ECE) described in other studies in animals.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Effects of rolipram and siguazodan on the human isolated bronchus and their interaction with isoprenaline and sodium nitroprusside.

1 The effects of the selective inhibitors of cyclic AMP phosphodiesterase type IV (rolipram) and type III (siguazodan) and their interactions with isoprenaline and sodium nitroprusside have been studied in the human isolated bronchus. 2 On bronchi under resting tone rolipram was, in terms of potency (pD2 = 7.77 +/- 0.14, n = 8), very similar to isoprenaline (pD2 = 7.31 +/- 0.12, n = 12) and salbutamol (pD2 = 7.12 +/- 0.17, n = 10) and approximately 10 fold more potent than siguazodan (pD2 = 6.80 +/- 0.12, n = 6). In terms of efficacy (Emax, expressed as percentage of maximal effect induced by theophylline 3 mM), both rolipram and siguazodan were less efficient (Emax = 74 +/- 6.7%, n = 8 and 66 +/- 7.5%, n = 6, respectively) than isoprenaline (Emax = 98 +/- 0.4%, n = 12) and salbutamol (Emax = 83 +/- 2.4%, n = 10). 3 During precontraction induced by methacholine (3 x 10(-7) M) or acetylcholine (10(-3) M), concentration-response curves to rolipram and siguazodan were shifted to the right and maximal effects reduced. Rolipram was more potent than siguazodan and, in terms of efficacy, it was less active. 4. Rolipram 10(-8) and 10(-7) M but not siguazodan potentiated the effects of isoprenaline as shown by the shift to the left of the concentration-response curve to isoprenaline. Sodium nitroprusside-induced relaxation was not modified by either drug. 5. These results show that rolipram is a potent relaxant of the human isolated bronchus, potentiating the effects of beta-adrenoceptor stimulation and suggest that, as previously demonstrated in other species(guinea-pig, cow) (Tomkinson et al., 1993), there may be a connection between the beta2-adrenoceptor subtype, which predominate in human airway smooth muscle, and the cyclic AMP phosphodiesterase type IV.

Albuterol↗
PubMed1994

Characterization of the tachykinin NK2 receptor in the human bronchus: influence of amastatin-sensitive metabolic pathways.

1. The aim of this study was to characterize the tachykinin NK2 receptor subtype mediating the spasmogenic response in the human isolated bronchus. The motor response to neurokinin A (NKA) and the selective NK2 agonist [beta Ala8]NKA(4-10), as well as the antagonistic effects of cyclic (L659,877) and linear (MEN 10376) peptide NK2 antagonists were assessed in the presence or absence of amastatin (an inhibitor of aminopeptidases A and M). 2. NKA was more potent than [beta Ala8]NKA(4-10) in eliciting bronchoconstriction (pD2 being 7,43 and 6,87 respectively). In the presence of amastatin (1 microM), the estimated affinity of [beta Ala8]NKA(4-10), but not that of NKA, was significantly increased to yield a pD2 of 7,44. 3. L659,877 and MEN 10376 inhibited [beta Ala8]NKA(4-10)-induced contraction with similar affinities; pA2 values were 5.7 +/- 0.22 and 6.3 +/- 0.32, respectively. Amastatin (1 microM) increased the potency of MEN 10376 to 7.28 +/- 0.46, whereas that of L659,877 was unaffected. 4. In the presence of amastatin the pseudopeptide MDL 28,564 behaved as a partial agonist. 5. We conclude that the NK2 receptor subtype present in the human bronchus has properties similar to those described for the circular muscle of the human colon and thus may be classified as a 'NK2A' subtype. We show that the apparent potency of peptides, bearing N-terminal acidic residues, is influenced by an amastatin-sensitive peptidase, possibly aminopeptidase A.

Amino Acid Sequence↗
PubMed1994

The interaction between salmeterol and beta 2-adrenoceptor agonists with higher efficacy on guinea-pig trachea and human bronchus in vitro.

1. In guinea-pig tracheal preparations precontracted with 1 mumol l-1 carbachol, formoterol, procaterol, fenoterol, salmefamol, salbutamol and terbutaline (in that order of potency) caused a concentration-dependent and almost complete, relaxation. However, under these conditions, the maximum relaxation by salmeterol was approximately 30% of the maximum attainable relaxation. 2. We have therefore explored the ability of salmeterol to inhibit the relaxant response to beta 2-adrenoceptor agonists of different chemical structure and relatively higher efficacy in smooth muscle preparations from guinea-pig trachea and human bronchus. 3. With 1 mumol l-1 salmeterol in the organ bath, the concentration-effect curves for the other agonists were shifted to the right in a variable way by 1.8-2.8 log units, fenoterol and salbutamol being the extremes. 4. When 20 mumol l-1 sulfonterol, another low efficacy beta 2-adrenoceptor agonist, was substituted for salmeterol, the difference in the magnitude of the rightward shift between fenoterol and salbutamol was eliminated. 5. In the human bronchus, formoterol and terbutaline had a higher apparent efficacy than salmeterol. With 1 mumol l-1 salmeterol in the organ bath, the concentration-effect curve for formoterol was shifted 2.7 log units to the right. 6. Salmeterol inhibits, competitively, relaxant responses to beta 2-adrenoceptor agonists with higher efficacy. The degree of inhibition seems to be dependent on the agonist used. This contrasts with results obtained with sulfonterol and suggests that salmeterol interacts with the beta 2-adrenoceptor in a complex way.

Adrenergic beta-2 Receptor Agonists↗
PubMed1995

Regulation by phosphodiesterase isoenzymes of non-adrenergic non-cholinergic contraction in guinea-pig isolated main bronchus.

1. We have investigated the role of phosphodiesterase isoenzymes in modulating electric field stimulation (EFS), substance P and capsaicin-induced contraction of the guinea-pig isolated main bronchus. 2. Non-adrenergic non-cholinergic contractile responses were elicited by EFS (3 Hz, 20 s) in the guinea-pig isolated main bronchus in the presence of the non-selective muscarinic antagonist, atropine (0.1 microM), the non-selective beta-adrenoceptor antagonist, propranolol (1 microM), the neutral endopeptidase inhibitor, thiorphan (10 microM) and the cyclo-oxygenase inhibitor, indomethacin (5 microM). The type III, type III/IV, type IV and type V phosphodiesterase isoenzyme inhibitor, SKF 94836, benzafentrine, Ro-20-1724 and zaprinast respectively, significantly attenuated the contractile response to EFS. The IC50 (95% confidence limits) value for SKF 94836, benzafentrine, Ro-20-1724 and zaprinast was 8.3 microM (0.89-78); 0.7 microM (0.1-4.5); 0.5 microM (0.2-1.2) and 13 microM (2-87) respectively. 3. The phosphodiesterase isoenzyme inhibitors, SKF 94836, Ro-20-1724 and zaprinast, partially attenuated the contractile response to substance P (10 nM). Benzafentrine significantly inhibited the contractile response to substance P, yielding an IC50 value of 1.9 microM (0.9-3.8). 4. The phosphodiesterase isoenzyme inhibitor, Ro-20-1724 (0.1-100 microM) failed to reduce significantly the contractile potency of capsaicin (P > 0.05). In contrast, SKF 94836 (1 microM), benzafentrine (10 microM) and zaprinast (100 microM) significantly reduced the contractile potency of capsaicin (P < 0.05). 5 The selective phosphodiesterase isoenzyme inhibitors, SKF 94836, benzafentrine, Ro-20-1724 andzaprinast (0.01-100 microM) reversed in a concentration-dependent manner the contractile response toexogenously administered capsaicin (EC50) yielding ICm values of 3.91 microM (0.68-22); 3.37 microM (1.86-6.11); 0.366 microM (0.201-0.564) and 50.1 microM (18.6- 135) respectively.6 In conclusion, phosphodiesterase isoenzymes appear to regulate the contractile response to electricalfield stimulation and our results provide circumstantial evidence for a regulatory role ofphosphodiesterase type IV isoenzyme on sensory nerve function in vitro.

Animals↗
PubMed1990

Effects of cularine and other isoquinoline alkaloids on guinea-pig trachea and human bronchus.

The relaxant effects of the isoquinoline alkaloids, cularine, antioquine, obaberine and 6, 7-dimethoxy-1, 2, 3, 4-tetrahydroisoquinoline, with structures related to that of papaverine, have been studied on the guinea-pig isolated trachea and human bronchus against contractions induced by acetylcholine (ACh), histamine, neurokinin A (NKA) and KCl. These effects were compared with those of papaverine and theophylline. Among the alkaloids tested, the most potent was cularine, the relaxant activity of which, in terms of pD2, was between those of papaverine and theophylline. The results showed that for the guinea-pig isolated trachea and the human bronchus, the cularine concentrations required to inhibit K(+)-induced contractions were close to those necessary to counteract ACh-, histamine- and NKA-induced contractions. The relaxant activity of cularine was not modified when it was tested on tracheal preparations under resting tone or after epithelium removal. In addition, cularine was able to inhibit Ca2(+)-induced contractions in a Ca2(+)-free, K(+)-enriched solution at the same concentrations as those which inhibited the action of the different contractile agents in normal Krebs solution. All these data show that cularine displays non-specific antispasmogenic activity on guinea-pig and human airways. The lower relaxant activity (pD2) of cularine compared with papaverine suggests the importance of free rotation of the isoquinoline-benzyl ring linkage as well as of the degree of hydrogenation of the heterocyclic ring in the spasmolytic effects of isoquinoline compounds.

Adenosine↗
PubMed1993

Effect of molsidomine and linsidomine on the human isolated bronchus and the guinea-pig isolated trachea.

The effects of molsidomine and its metabolite linsidomine were studied on the guinea-pig isolated trachea and on the human isolated bronchus. These effects were compared with those of nitrate derivatives (sodium nitroprusside, isosorbide dinitrate), theophylline, zardaverine and isoprenaline. Linsidomine exerted a relaxant effect similar to that of sodium nitroprusside on the two types of preparations precontracted with acetylcholine, histamine or potassium chloride. Molsidomine was about one-hundredth as potent as linsidomine, and less efficacious. The effects of the two substances were not modified by removal of the human bronchial epithelium. The concentration-response curves of linsidomine and sodium nitroprusside were significantly shifted to the right by methylene blue (3 x 10(-5) M) but the effects of isoprenaline were unmodified. The effects of linsidomine and sodium nitroprusside were potentiated specifically by zaprinast (10(-6)-10(-5) M), an inhibitor of type Ia or V phosphodiesterases, whereas the effects of isoprenaline were potentiated by zardaverine (10(-9)-10(-8) M), an inhibitor of class III and IV phosphodiesterases. The effects of all three substances (linsidomine, isoprenaline and sodium nitroprusside) were potentiated equally by theophylline (10(-5)-10(-4) M), a nonspecific inhibitor of phosphodiesterases. It is concluded that linsidomine is a potent relaxant of the smooth muscle of the guinea-pig isolated trachea and human isolated bronchus. In terms of potency and efficacy, its effect is much superior to that of the parent compound molsidomine. It is suggested that linsidomine acts, like nitrate derivatives, through the guanylate cyclase-cGMP system.

Animals↗
PubMed1965

Phycomycosis of the bronchus.

A case of phycomycosis of the bronchus in a 29-year-old diabetic man is reported. The interval between infection and death was not less than 35 days. Infection of the bronchus appears to have been direct. The diagnosis of phycomycosis could have been made before death.

Adult↗
PubMed1979

Resection of proximal left main bronchus carcinoma.

A carcionoma at the orifice of the left main bronchus is generally considered inoperable. Since 1963, in six patients, we have mobilised the transverse aortic arch and, working above the aortic arch, cut the left main bronchus off the trachea and closed the stump. The operation is completed as a pneumonectomy; it is referred to as a supra-aortic pneumonectomy. The indications, technique, and results are described.

Adult↗
PubMed1980

Survival after resection of small cell carcinoma of the bronchus.

Forty patients who underwent curative resection for oat cell carcinoma of the bronchus between 1959 and 1974 are reviewed. During the same period there were 24 patients who underwent thoracotomy but who were found to have inoperable lesions. Of the 40 patients who underwent curative resection, 11 patients remain alive and well with no evidence of recurrence. Ten of these patients have survived five years or more, an overall five-year survival rate of 25%. We consider that surgery should be considered as a possible first line of treatment in patients with small cell carcinoma of the bronchus.

Adult↗
PubMed1984

Carcinoid tumours of the bronchus: a 33 year experience.

The term adenoma of the bronchus is discussed, and 79 cases of bronchial carcinoid seen from 1951 to 1983 are reviewed. The symptoms, radiological findings, and bronchoscopic appearances are described. There was no case of the carcinoid syndrome. In no case did haemorrhage cause any serious problem after biopsy at rigid bronchoscopy. In three patients the tumour was reported to be an oat cell carcinoma-in two on the basis of material obtained at fibreoptic bronchoscopy. Resection was by pneumonectomy in 10 cases, lobectomy in 52, segmentectomy in six, a bronchoplastic procedure without resection of lung in seven cases, enucleation in two, and a wedge resection in one case. There was one case of atypical carcinoid which was found at operation to be unresectable. A 5-30 year follow up in 57 cases revealed a recurrence of tumour in two cases, nine and 16 years after lung resection. No recurrence occurred in the nine cases treated by conservative bronchial resection with conservation of lung tissue. An actuarially assessed life table analysis shows survival rates of 94% after 10 years, 80% after 15 years, and 64% after 25 years without recurrence. The similarity of carcinoid to oat cell carcinoma is noted and the serious clinical implications of this are analysed, especially in view of the increasing use of fibreoptic bronchoscopy. The malignant potential of carcinoid and the extent of pulmonary resection is discussed. It is concluded that a carcinoid tumour of the lung has only slight malignant potential and that it may be treated by bronchotomy or sleeve resection of the bronchus in suitable cases. If serious infective changes have occurred in the lung distal to the tumour or if the tumour has extended into the lung parenchyma (88% of cases in this series) lung resection will be necessary. The follow up period should be for at least 25 years, in view of the incidence of late recurrence.

Adolescent↗
PubMed1985

Solitary squamous papilloma of the bronchus.

A case of solitary squamous papilloma of the bronchus is described and 11 other cases from the reports published worldwide are reviewed. These tumours present in middle aged men with symptoms similar to those of bronchial carcinoma. Treatment by bronchoscopic removal or lobectomy is usually curative. Symptoms are similar to those of bronchial carcinoma, but a correct preoperative diagnosis permits more conservative surgery to be carried out. Difficulties in the histological classification of papillary tumours of the bronchus are discussed.

Aged↗
PubMed1991

Interphase nucleolar organiser regions and survival in squamous cell carcinoma of the bronchus: a 10 year follow up study of 138 cases.

BACKGROUND: Good prognostic indicators for patients with squamous cell carcinoma of the lung would help to determine the most appropriate treatment for individual patients. METHODS: A silver colloid technique that shows interphase nucleolar organiser regions (AgNORs) has been applied to representative paraffin sections from 138 cases of squamous cell carcinoma of the bronchus treated by surgical resection of the primary tumour at East Birmingham Hospital in 1977. Of the 138 patients, 23 (17%) were alive 10 years after their operation. RESULTS: The mean (SD) AgNOR count per cell was significantly higher for all grades of malignancy (well differentiated 10.5 (2.6), moderately differentiated 10.7 (3.2), and poorly differentiated 12.7 (4.5)) than for normal pseudostratified columnar epithelium from non-affected areas (2.3 (0.78)). There was a trend for AgNOR counts to be higher in poorly differentiated tumours, but a wide range of AgNOR counts was observed in all histological grades. AgNOR counts did not predict clinical outcome, irrespective of the stage of the disease, and did not relate to DNA ploidy or the percentage of cells in the proliferation phase of the cell cycle. Nine of 47 patients (19%) with tumours classified as DNA diploid and eight of 63 patients (13%) with DNA aneuploid tumours were alive 10 years after operation. Principal component analysis identified the clinicopathological stage of disease as the variable best related to survival. The percentage of patients surviving 10 years was 30% for stage I, 20% for stage II, 10% for stage IIIa, 9% for stage IIIb, and none for stage IV. CONCLUSION: The AgNOR technique is not of prognostic value in postoperative patients with squamous cell carcinoma of the bronchus.

Adult↗
PubMed1993

Static lung volumes in healthy subjects assessed by helium dilution during occlusion of one mainstem bronchus.

BACKGROUND: Single lung function is usually assessed by radioisotopes or, more rarely, by bronchospirometry in which a double lumen catheter is used to separate ventilation of the two lungs. The latter is more precise but less comfortable. An alternative bronchoscopic method is described for determining the volume of a single lung. METHODS: One mainstem bronchus was temporarily occluded with an inflatable balloon during fibreoptic bronchoscopy in 12 healthy volunteers aged 18-29 years. The functional residual capacities (FRC) of the right, left, and both lungs were measured in duplicate by closed circuit helium dilution. Supplementary vital capacity (VC) manoeuvres permitted calculation of single lung capacities (TLC) and residual volumes (RV). RESULTS: The standard deviation of a single determination of capacities of the right, left, and both lungs were: TLC, 80, 96, and 308 ml; VC, 56, 139, 171 ml; FRC, 131, 74, and 287 ml; RV, 112, 185, and 303 ml, respectively. The sum of the right and left unilateral TLC was not different from bilateral TLC (6.12 v 5.95 l) and the sum of the unilateral FRC was not different from the bilateral FRC (2.60 v 2.78 l). The sum of the unilateral VC was lower than bilateral VC (4.52 v 4.80 l), that of the unilateral RV was higher than bilateral RV (1.60 v 1.16 l). For all subdivisions of lung volume, the right lung was larger than the left. The most common complaint was substernal discomfort during complete exhalation. Oxygen saturation rarely fell below 90%. CONCLUSIONS: Temporary occlusion of a mainstem bronchus in normal subjects is safe, relatively simple, and allows fairly precise and accurate measurements of unilateral static lung volumes. Occlusion at TLC, however, probably prevents proper emptying of the non-occluded lung.

Adolescent↗