Airway circulation in health and disease.
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Bronchi↗
Biomedical subjects
P Paré
Publications and source records attributed to P Paré.
Endogenous nitric oxide influences acetylcholine-induced bronchovascular dilation in sheep.
To test whether endogenous endothelial nitric oxide (NO) influences baseline bronchial vascular tone and mediates acetylcholine (ACh)-induced bronchial vascular dilation and/or modulates bronchoconstriction in ovine airways, we studied anesthetized ventilated open-chest sheep and measured bronchial blood flow (Qbr) and pulmonary resistance (RL). In six sheep we measured the response of Qbr and RL to the dose of ACh required to produce 50% of the maximal increase in Qbr at baseline during infusion of the NO synthase inhibitor NG-nitro-L-arginine (L-NNA; 10(-2) M). Infusion of L-NNA decreased both the baseline Qbr (28 +/- 13 to 8 +/- 2 ml/min, P < 0.01) and the change in Qbr (delta Qbr) from the baseline value (84 +/- 42 to 33 +/- 18 ml/min, P < 0.05). There was no difference in baseline RL or in the response of RL to ACh at any time. In another six sheep, phenylephrine (5 x 10(-6) to 5 x 10(-7) M) decreased baseline Qbr (22 +/- 6 to 10 +/- 3 ml/min, P < 0.05) but not delta Qbr (62 +/- 13 to 66 +/- 21 ml/min, not significant). Infusion of L-NNA in these sheep decreased the baseline Qbr to a similar extent (11 +/- 5 ml/min) and also decreased delta Qbr (42 +/- 16 ml/min, P < 0.05). We conclude that endogenous endothelial NO influences baseline vascular tone and ACh-induced vasodilation of the ovine bronchial vasculature but has no effect on baseline RL or ACh-induced bronchoconstriction.
Acetylcholine↗
Relation of smoking to immunoreactive endothelin in the bronchiolar epithelial cells.
BACKGROUND: Endothelin is a potent bronchoconstrictor which appears to be important in asthma. To ascertain whether cigarette smoking is associated with any alteration in the proportion of bronchiolar epithelial cells which express endothelin immunoreactivity, the airways in the lungs of non-smokers and smokers were analysed. Since an increase in immunoreactivity has been found in the bronchial epithelial cells of asthmatic subjects, cigarette smokers with and without evidence of airway hyperresponsiveness were also selected. METHODS: A point counting method which examined the proportion of endothelin immunoreactive epithelial cells in membranous and respiratory bronchioles was used. RESULTS: Neither smoking itself nor evidence of airway hyperresponsiveness altered the percentage of endothelin immunoreactive epithelial cells in the membraneous and respiratory bronchioles. CONCLUSIONS: Cigarette smoke does not induce endothelin production in bronchiolar epithelial cells, and the airway hyperresponsiveness seen in some patients with lung disease induced by cigarette smoking is not related to exaggerated endothelin production in epithelial cells.
Bronchi↗
Blood flow distribution to upper airway muscles.
Radiolabeled (15-microns) microspheres were used to measure blood flow to upper airway muscles [alae nasi (AN), intrinsic laryngeal, tongue, cervical strap, and hyoid musculature], diaphragm (DI), and parasternals (PS) during spontaneous breathing in 24 anesthetized tracheotomized supine dogs. Six dogs were also studied while -28 +/- 3 (SE) cmH2O tracheal airway pressure was generated against an inspiratory resistance (IR) (upper airway bypassed). Blood flow to posterior cricoarytenoid muscle (PCA) [24.0 +/- 2.1 (SE) ml.min-1.100 g-1] was greater than that to DI (18.0 +/- 2.3 ml.min-1.100 g-1) and comparable to that to PS (21.4 +/- 2.9 ml.min-1.100 g-1). Blood flow per unit weight did not differ between AN, tongue muscles, laryngeal adductors, cervical strap muscles, and cricothyroid (CT). Average blood flow to these muscles was only 8.0 +/- 0.8 ml.min-1.100 g-1. With the exception of CT, blood flow to these upper airway muscles was less than that to DI and PCA. Relative to blood flow during spontaneous breathing, IR loading increased blood flow to AN by a factor of 7.5, to PCA by 3.4, to DI by 3.2 and to PS by 1.9. There was no change in blood flow in the other muscles during loading. Our results show that at rest blood flow to main glottic dilator (PCA) is similar to that to main inspiratory muscles. Furthermore, in response to an IR load, blood flow to PCA and AN increased by an equivalent or greater amount than that to DI.(ABSTRACT TRUNCATED AT 250 WORDS)
Airway Resistance↗
In vivo loads on airway smooth muscle: the role of noncontractile airway structures.
The degree of airway smooth muscle contraction and shortening that occurs in vivo is modified by many factors, including those that influence the degree of muscle activation, the resting muscle length, and the loads against which the muscle contracts. Canine trachealis muscle will shorten up to 70% of starting length from optimal length in vitro but will only shorten by around 30% in vivo. This limitation of shortening may be a result of the muscle shortening against an elastic load such as could be applied by tracheal cartilage. Limitation of airway smooth muscle shortening in smaller airways may be the result of contraction against an elastic load, such as could be applied by lung parenchymal recoil. Measurement of the elastic loads applied by the tracheal cartilage to the trachealis muscle and by lung parenchymal recoil to smooth muscle of smaller airways were performed in canine preparations. In both experiments the calculated elastic loads applied by the cartilage and the parenchymal recoil explained in part the limitation of maximal active shortening and airway narrowing observed. We conclude that the elastic loads provided by surrounding structures are important in determining the degree of airway smooth muscle shortening and the resultant airway narrowing.
Animals↗
Aerosol pentamidine-induced bronchoconstriction. Predictive factors and preventive therapy.
OBJECTIVE: To describe the frequency of aerosol pentamidine-induced bronchoconstriction, its relationship to non-specific airway responsiveness, and its response to preventive therapy using salbutamol, ipratropium bromide, or sodium cromoglycate. METHODS: Consecutive HIV-infected individuals starting prophylactic AP were eligible if they had not been previously treated with this agent. Simple spirometry was performed before and 10 min after a single 60-mg dose given through an ultrasonic nebulizer. Methacholine challenge was performed in all subjects 24 h to four days after the initial AP dose. Subjects with a change in FEV1 (delta FEV1) greater than or equal to 10 percent decrease after the initial AP dose were restudied on three separate occasions (greater than 24 hours apart) after premedication with two puffs of salbutamol (200 micrograms), ipratropium bromide (40 micrograms), or sodium cromoglycate (2 mg), in random order. RESULTS: Fifty-three subjects were studied. The median delta FEV1 after a single dose of AP was -7.0 percent (range: -47 percent, 1.8 percent). The delta FEV1 following AP was only partially predicted by the degree of nonspecific bronchial responsiveness as measured by a standard methacholine challenge. Age, current smoking, history of asthma, baseline FEV1, or a prior episode of PCP failed to predict the delta FEV1 following AP. Eighteen subjects (34 percent) had a delta FEV1 greater than or equal to 10 percent decrease (median: -17.0 percent). In these subjects, after premedication with salbutamol, ipratropium bromide, and sodium cromoglycate, the median delta FEV1 was 1.0, 0.8, and -9.6 percent, respectively. CONCLUSION: Aerosol pentamidine produced a decrease in FEV1 greater than or equal to 10 percent in 34 percent of subjects. This was not accurately predicted by the methacholine response. The bronchoconstriction induced by AP was effectively prevented by either salbutamol or ipratropium, whereas cromoglycate was only partially effective.
Adult↗
Tracheal smooth muscle mechanics in vivo.
We applied the technique of sonomicrometry to directly measure length changes of the trachealis muscle in vivo. Pairs of small 1-mm piezoelectric transducers were placed in parallel with the muscle fibers in the posterior tracheal wall in seven anesthetized dogs. Length changes were recorded during mechanical ventilation and during complete pressure-volume curves of the lung. The trachealis muscle showed spontaneous fluctuations in base-line length that disappeared after vagotomy. Before vagotomy passive pressure-length curves showed marked hysteresis and length changed by 18.5 +/- 13.2% (SD) resting length at functional residual capacity (LFRC) from FRC to total lung capacity (TLC) and by 28.2 +/- 16.2% LFRC from FRC to residual volume (RV). After vagotomy hysteresis decreased considerably and length now changed by 10.4 +/- 3.7% LFRC from FRC to TLC and by 32.5 +/- 14.6% LFRC from FRC to RV. Bilateral supramaximal vagal stimulation produced a mean maximal active shortening of 28.8 +/- 14.2% resting length at any lung volume (LR) and shortening decreased at lengths above FRC. The mean maximal velocity of shortening was 4.2 +/- 3.9% LR.S-1. We conclude that sonomicrometry may be used to record smooth muscle length in vivo. Vagal tone strongly influences passive length change. In vivo active shortening and velocity of shortening are less than in vitro, implying that there are significant loads impeding shortening in vivo.
Animals↗
Adult celiac sprue: changes in the pattern of clinical recognition.
We report the clinical, laboratory, and pathological findings in a series of 52 consecutive patients with adult celiac sprue observed over a 20-year period. The frequency of that diagnosis increased from an average of 0.7 case/year during the period 1966-1975 to 5.8 cases/year during the period 1981-1985. Apart from two patients with dermatitis herpetiformis, nonclassical clinical presentations were observed in 16 of 50 (32%) patients overall and in 13 of 28 (46%) patients diagnosed since 1981. Diarrhea was the most common complaint leading to the diagnosis; since 1981, hematologic abnormalities warranted investigation in 38% of the patients. Decreased iron stores (88%), decreased red cell folate (82%), or both (74%), and abnormal radiographic studies of the small bowel (83%) were the most sensitive tests in the diagnostic investigation. We conclude that atypical or nonclassical presentations of adult celiac sprue, mostly with hematologic abnormalities, are not uncommon.
Abdomen↗
Differential diagnosis of bronchiolitis obliterans with organizing pneumonia and usual interstitial pneumonia: clinical, functional, and radiologic findings.
To assess the role of chest radiography in the differential diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP) and usual interstitial pneumonia (UIP), records of 34 patients with biopsy-proved BOOP (16 patients) or UIP (18 patients) were reviewed. Chest radiographs taken before biopsy were available in 26 patients, clinical information in 33, and pulmonary function data in 22. These data were reviewed independently, without knowledge of the pathologic diagnosis. The clinical symptoms of BOOP were similar to those of UIP, although the duration of symptoms was longer in UIP (P less than .05), and the prevalence of systemic symptoms was higher in BOOP (P less than .025). The physical findings were similar except that finger clubbing was more common in patients with UIP than in those with BOOP (P less than .01). There was no significant difference in lung volumes, flows, or diffusing capacity between BOOP and UIP. The chest radiograph showed distinguishing features between UIP and BOOP in 23 of 26 patients. The most characteristic radiologic finding in BOOP was the presence of patchy areas of air-space consolidation (eight of 11 patients).
Adult↗
A comparative trial of ranitidine 300 mg at night with ranitidine 150 mg twice daily in the treatment of duodenal and gastric ulcer.
A multicenter double-blind comparative trial of oral ranitidine, 300 mg hs versus 150 mg bid, was conducted in 89 patients with duodenal ulcer (DU) and 54 with gastric ulcer (GU). Antacid tablets were prescribed prn. After 4 wk of treatment there were no statistically significant differences in the ulcer healing rates associated with the once daily (DU 86.4%, GU 62.5%) and the twice daily (DU 84.4%, GU 73.3%) regimens. Antacid consumption, by both DU and GU patients, was higher in the 150 mg bid group, but the differences did not achieve statistical significance. Further improvement in cumulative healing rates in response to both treatment regimens was observed following a second 4-wk treatment for those patients whose ulcers had failed to heal during the 1st month. Smoking adversely affected the rate of ulcer healing in DU patients, but had no significant effect on GU healing. No serious adverse effects or biochemical abnormalities were observed. Ranitidine 300 mg hs appears to be equally safe and effective as the standard regimen of 150 mg bid in the short-term treatment of uncomplicated gastroduodenal ulcer.
Adult↗
Impaired renal acidification in alcoholic liver disease.
The prevalence of impaired renal acidification in alcoholic liver disease and its relationship to clinical and biochemical features were evaluated during a one-year period in a 60-bed liver unit. No cases of overt renal tubular acidosis (RTA) were found; all of 12 patients with low serum bicarbonate values and normal anion gap proved to have chronic respiratory alkalosis. However, there was a 57% prevalence of incomplete distal RTA in 42 patients who were tested with an acid load. Subjects with RTA had higher serum bilirubin levels (5.3 +/- 6.1 v 2.1 +/- 2.7 mg/dL) and lower prothrombin times (45% +/- 22% v 64% +/- 20%). Urinary pH correlated directly with serum bilirubin levels (r = +.38) and inversely with prothrombin times (r = -.46). The frequency of ascites and encephalopathy did not differ notably between the two groups of patients. No pathogenetic relation was observed with avid sodium retention, decreased excretion of nonreabsorbable anions, and elevated urinary excretion of bile acids. Therefore, we conclude that impaired renal acidification in alcoholic liver disease may be a sign of liver cell failure since it is more frequently observed in patients with a greater degree of liver dysfunction.
Acid-Base Equilibrium↗
Bile-duct cyst with cystlithiasis: a case report.
Cystic dilatation of the biliary tree is an uncommon congenital condition, most often discovered in infancy. It should be suspected in an adult who has a history, over a long period, of intermittent pain in the right upper quadrant, episodes of jaundice or cholangitis, or both, and has a palpable mass in the right hypochondrium. Ultrasonography and especially endoscopic retrograde cholangiopancreatography allow the biliary cyst to be diagnosed preoperatively more often than previously. The authors describe the case of a 60-year-old woman with congenital cystic dilatation of extra- and intrahepatic bile ducts with cystlithiasis that followed an unusual course. Of the various theories of causation, Babbitt 's is now the most widely accepted, especially since the advent of endoscopic retrograde cholangiopancreatography. The presence of stones is an uncommon and late complication. The treatment is surgical, excision of the biliary cysts being the treatment of choice; however, Roux-en-Y choledochocystojejunostomy is performed when excision is technically impossible.
Bile Duct Diseases↗
Effect of ranitidine on healing of peptic ulcer: a 2-month study.
A multicenter trial of oral ranitidine 150 mg bid was conducted in 41 patients with duodenal and 30 with gastric ulcers. Patients were randomly allocated in double-blind fashion to 4 wk treatment with either ranitidine or placebo, after which all unhealed patients were given 4 wk on the active drug without breaking the original allocation code. After 4 wk of treatment the healing rate associated with ranitidine was significantly superior to that of placebo in both duodenal and gastric ulcer patients. Further improvement in cumulative healing rates was observed after the 2nd month of the study. After the allocation code was broken and all patients had had the opportunity of up to 8 wk on the active drug, there remained only a single unhealed pyloric ulcer. No serious adverse effects or biochemical abnormalities were observed. Ranitidine is a potent and well-tolerated H2 antagonist. Therapy for 4 or 8 wk is highly effective in the treatment of uncomplicated gastroduodenal ulcer.
Adult↗
Serum-ascites albumin concentration gradient: a physiologic approach to the differential diagnosis of ascites.
Serum-ascites albumin concentration gradient, a parameter of oncotic pressure gradient reflecting presence or absence of portal hypertension, was compared with the usual parameters of ascitic fluid analysis in the differential diagnosis of ascites. Twenty-nine patients with liver disease and 15 patients with malignant neoplasm were prospectively studied. The group with malignant neoplasm showed higher ascitic fluid total protein level (3.70 +/- 1.28 vs. 1.66 +/- 1.20 g/dl), ascites to serum ratio of total protein level (0.58 +/- 0.14 vs. 0.26 +/- 0.14), ascitic fluid lactic dehydrogenase level (756 +/- 693 vs. 151 +/- 125 U/L), ascites to serum ratio of lactic dehydrogenase level (1.13 +/- 0.79 vs. 0.35 +/- 0.22), and lower serum-ascites albumin gradient (0.72 +/- 0.30 vs. 1.85 +/- 0.45) (p less than 0.001 for all parameters). Results of the serum-ascites albumin gradient overlapped the least between the two groups: all but 1 patient with malignant ascites while only 1 patient with liver disease had a gradient lower than 1.1. We conclude that the serum-ascites albumin gradient offers the best diagnostic discrimination between ascites caused by liver disease and ascites caused by a neoplasm.
Ascites↗
Double-blind, controlled trial of propylthiouracil in patients with severe acute alcoholic hepatitis.
Sixty-seven patients entered a double-blind, controlled trial to evaluate the efficacy of propylthiouracil treatment in severe alcoholic hepatitis. Twenty-three percent (7 of 31) given propylthiouracil and 19% (7 of 36) given placebo died during the 6-wk study. Propylthiouracil treatment did not reduce the frequency and incidence of complications in alcoholic hepatitis, but induced hypothyroidism in 4 patients. Treatment produced no beneficial effect on any of the hepatic biochemical tests. We were unable to show any beneficial effect of propylthiouracil treatment on morbidity and mortality in patients with severe acute alcoholic hepatitis.
Adult↗
Determinants of serum bile acids in chronic liver disease.
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Bile Acids and Salts↗
The effect of H2-blocking agents on systemic anaphylaxis in guinea pigs.
Theoretically, histamine H2 antagonists could aggravate allergic bronchoconstriction (1) by increasing mediator release, and (2) by blocking histamine-induced bronchodilatation. We measured dynamic compliance, subdivisions of lung volume, and mortality in immunized guinea pigs after parenteral administration of antigen, with and without pretreatment with the H2-blocking agents cimetidine and metiamide. Administration of antigen caused significant mortality as well as decreases in dynamic compliance, total lung capacity, and vital capacity and increases in functional residual capacity. The prior administration of cimetidine or metiamide did not protect against or enhance these effects of antigen challenge.
Anaphylaxis↗
Nonvisualization of the gallbladder by 99mTc-HIDA cholescintigraphy as evidence of cholecystitis.
Cholescintigraphy with N-substituted iminodiacetic acid (HIDA) labelled with technetium-99m is a new noninvasive technique for evaluation of the hepatobiliary system. The significance of nonvisualization of the gallbladder by this method in comparison with standard radiologic examinations was studied. In 43 healthy subjects the gallbladder was visualized by the two methods. By contrast, all 27 patients in whom the gallbladder was not visualized by cholescintigraphy had cholecystitis. When visualization failed to occur, a repeat cholescintigraphic study after an injection of cholecystokinin demonstrated the status of the cystic duct. Visualization excludes cystic duct obstruction and acute cholecystitis, whereas persistent nonvisualization indicates cystic duct obstruction.
Acetanilides↗