Allergen challenge-induced entry of alpha 2-macroglobulin and tryptase into human nasal and bronchial airways.

BACKGROUND: Microvascular-epithelial exudation of bulk plasma may characterize inflammatory airway diseases. This study compares the acute allergen challenge-induced mast cell and exudative responses in nasal and bronchial airways. The focus is on alpha 2-macroglobulin as an index of luminal entry of plasma exudates. METHODS: Separate nasal and bronchial allergen challenges were carried out outside the pollen season in eight patients with pollen-induced seasonal allergic rhinitis. The levels of different-sized plasma proteins (albumin molecular weight, 66,000 d and alpha 2-macroglobulin molecular weight, 725,000 d) and tryptase were determined in pre- and postchallenge nasal lavage and bronchoalveolar lavage (BAL) fluids. Diluent and increasing doses of allergen were sprayed into the right nasal cavity, and each challenge was followed by a nasal lavage (volume, 15 ml) with a "nasal pool" device (recovery, > 80%). Endobronchial allergen challenge (individual doses) and BAL (volume, 2 x 25 ml) were performed in a lobe bronchus through a fiberoptic bronchoscope (recovery, 30%). Saline challenge and BAL were carried out in the contralateral lung as control. RESULTS: The levels of albumin, alpha 2-macroglobulin, and tryptase increased dose-dependently in postchallenge nasal lavage fluids (p < 0.05) and correlated to nasal symptoms. In particular, albumin and alpha 2-macroglobulin correlated (r = 0.98, p < 0.001). Both alpha 2-macroglobulin and tryptase, but not albumin, were increased in BAL fluids from the allergen-challenged side (p < 0.05). CONCLUSION: Local allergen challenge causes luminal entry of tryptase and alpha 2-macroglobulin in the nose and bronchi of patients with allergy. We suggest that mast cell and plasma exudation responses may be similar in human nasal and bronchial airways and that albumin levels (in BAL fluids) may not well reflect the exudation process in bronchial airways.

Investigation of the role of reactive oxygen species in bilirubin metabolism in the Gunn rat.

It has been previously established that the attenuation of hepatic lipid peroxidation by a fat-free diet is accompanied by a marked rise in plasma bilirubin in Gunn rats. Present in vitro studies confirmed that microsomal lipid peroxidation caused the concurrent degradation of added bilirubin but failed to show that microsomal superoxide, hydroxyl radical or hydrogen peroxide would degrade bilirubin. Moreover, although injection of vitamin E completely inhibited microsomal lipid peroxidation and bilirubin degradation it had no effect on plasma bilirubin. No evidence has therefore been obtained that in Gunn rats, in the absence of bilirubin glucuronidation, that reactive oxygen species provide a significant physiological pathway of bilirubin disposal.

Dose intensity of the CAVE regimen in small cell lung cancer correlates to response rate.

Sixty-three patients with limited or extensive small cell lung cancer (SCLC), were treated in the Department of Respiratory Diseases, Huddinge Hospital, between 1985 and 1990, with chemotherapy consisting of cyclophosphamide, doxorubicin, vincristine and etoposide (CAVE). The patients were analyzed retrospectively concerning dose intensity (DI) of the chemotherapy actually delivered during induction treatment, the response rate, toxicity and survival. The mean combined relative DI (CRDI) of the induction treatment, consisting of three chemotherapy courses, was 0.7 (projected CRDI = 1.0). The overall response rate was 57% and the median survival time was 291 days. We found a correlation between the combined relative DI (all four drugs together) and the response rate. Increasing the CRDI from the range of 0.28-0.6 to 0.76-0.90 resulted in an increase in the response rate from 35 to 90%. Toxicity was scarce, suggesting that the actual delivered chemotherapy had low intensity. No correlation was found between DI and toxicity or between the response rate and toxicity. A correlation between DI of this induction treatment and survival could not be established. Our findings suggest the utility of reporting the actual DI of chemotherapy trials in SCLC.

Bronchial exudation of bulk plasma at allergen challenge in allergic asthma.

This study examined plasma exudation into the bronchial lumen after allergen challenge. A novel low-trauma technique was developed to challenge and lavage a medium-sized lingular or middle lobe bronchus. Eleven subjects with challenge-assessed pollen-sensitive asthma were allocated to fiberbronchoscopy in the supine position. In the control bronchus 0.5 ml diluent was instilled. The bronchus was occluded proximally 3 min later by inflation of a balloon, and lavage was carried out twice with 25 ml saline. Incremental doses of allergen solution (0.5 ml) were then instilled in the contralateral lung. The challenge continued until a clearly visible bronchial reaction occurred and was immediately followed by the same lavage as on the control side. The lavage liquids were analyzed for the presence of plasma exudation and mast cell activation indices. On the allergen-challenged side, tryptase, reflecting mast cell activation, was increased by 150% (p < 0.01) compared with the control side. Fibrinogen (mol wt 340,000), reflecting large protein exudation, was increased by 840% (p < 0.05), and N-alpha-tosyl-L-arginine-methyl esterase activity, reflecting both large protein exudation and mast cell activation, increased by 480% (p < 0.01). The level of albumin (mol wt 69,000), the major luminal protein under baseline conditions, increased but not significantly. We conclude that activation of mast cells and luminal entry of little sieved plasma exudates occur early after endobronchial allergen provocation in human subjects with allergic asthma.

Expired-breath ethanol measurement in chronic obstructive pulmonary disease: implications for transurethral surgery.

If ethanol is added to the irrigant used during transurethral prostatic resection, the absorption of fluid can immediately be detected by measuring the ethanol concentration in the expired breath. To evaluate this method further, we studied the influence of chronic obstructive pulmonary disease (COPD) on the agreement between expired-breath and blood-ethanol concentrations. In 14 men with a mean age of 62 years (range 55-68), the concentrations of ethanol in whole blood and end-expired breath were measured at 12 exactly timed intervals before, during, and after an intravenous infusion of 0.6 g.kg-1 ethanol for 60 min. The pulmonary function was normal in seven of the subjects (control group) whereas the other seven suffered from severe COPD (study group). The results show that the accuracy and precision of breath-alcohol analysis to predict the blood-ethanol level were poorer during the infusion of ethanol than afterwards. However, at all times of sampling the estimation of blood-ethanol concentration indirectly by analysis of breath was not significantly different for COPD patients and the control group. We conclude that ethanol monitoring of irrigant absorption can be used successfully in patients with COPD.

Dietary modulation of plasma bilirubin and of hepatic microsomal lipid peroxidation in the Gunn rat.

An in vitro assay for the simultaneous measurement of lipid peroxidation (LPO) and bilirubin degradation (BRD) activities in rat liver microsomes has been developed; a good correlation between the 2 activities was observed (r = 0.78). In the Gunn rat a lipid free diet caused an increase in plasma bilirubin (62.4 +/- 25.8%, n = 6) and a concomitant decrease in both hepatic microsomal LPO and BRD to zero. In contrast, on a 25% lipid diet there was a decrease in plasma bilirubin (46.1 +/- 3.6%; n = 8) associated with an increase in LPO (1.26 +/- 0.11 nmol/min/mg protein, and BRD (0.21 +/- 0.6 nmol/min/mg protein). Therefore, in the absence of bilirubin glucuronidation, dietary modulation of plasma bilirubin and lipid peroxidation appear to be closely associated.

Induction of theophylline metabolism by pentobarbital.

Theophylline concentrations in plasma and urine were determined during maintenance treatment in nine healthy volunteers during one dosage interval before and after 10 days of simultaneous treatment with pentobarbital (100 mg each night). During the pentobarbital period, total plasma clearance of theophylline increased by 40% (range -4-79%), whereas renal clearance remained unchanged. It is concluded that therapeutic doses of pentobarbital induce the metabolism of theophylline with marked interindividual variation.

Felodipine reduces the absorption of theophylline in man.

Ten healthy male volunteers (mean age 26 years) received 200 mg theophylline aminopropanol orally 8-hourly for 4 days, followed by 5 mg felodipine 8-hourly for 6 days, and then the combination of oral felodipine and theophylline for a further 4 days. Plasma concentrations of theophylline and felodipine were determined, and theophylline and its metabolites in urine were also measured. Felodipine led to a reduction in the plasma AUC of theophylline of 18.3%. The metabolic and renal clearances of theophylline remained unchanged, but the total recovery of theophylline-derived products was significantly reduced during felodipine treatment. No change in felodipine pharmacokinetics was observed during simultaneous treatment with theophylline. Compared to theophylline treatment alone, the diastolic blood pressure was significantly reduced during felodipine treatment alone and in combination with theophylline. It is concluded that felodipine slightly but significantly lowered the plasma theophylline concentration by interfering with its absorption. The interaction in most instances would probably be of minor clinical consequence.

The effect of secretin on bile flow and bile acid and bilirubin excretion following relief of prolonged bile duct obstruction in the rat.

Bile flow was re-established in rats whose bile ducts had been obstructed for 5, 10, 15 and 28 days (Groups I, II, III and IV, n = 5). The effect of i.v. secretin on bile flow in control rats, whose bile ducts had been cannulated, was minimal, but in cholestatic rats there was an immediate response which was related to the duration of the obstruction and the degree of bile duct proliferation. In 40 min the mean excess bile flow production amounted to 76, 258, 320 and 432 microliters/100 g body wt. in Groups I, II, III and IV, respectively. Choleresis was prolonged in the Group IV rats that had developed cirrhosis. Synthetic secretin had a minimal effect on bile acid and bilirubin excretion. It is postulated that the proliferating bile ductules are the site of secretin choleresis, although the possibility that reduced inactivation of the hormone plays a role cannot be excluded.

Enzymatic oxidation of bilirubin by intestinal mucosa.

Bilirubin oxidase, an aerobic enzyme which degrades bilirubin 'in vitro' to colourless diazo-negative compounds, including propentdyopents and trace amounts of biliverdin, has been demonstrated in homogenates of rat intestine, kidney and liver. The enzyme in the intestinal mucosa has been partially characterised and appears to be mitochondrial in origin; maximal activity was detected in the jejunum. Intestinal bilirubin oxidase has a mean activity of 0.51 +/- 0.03 (S.D.) nmol bilirubin degraded/min per mg protein. Similar bilirubin oxidase activities were found in the tissue of Sprague-Dawley and Gunn rats. The role of the enzyme 'in vivo' remains to be determined.

The use of Bond-Elut for the estimation of serum bile pigments bonded covalently to albumin.

A simple and precise method has been devised for the quantitation of biliprotein (delta-bilirubin or albumin bound bilirubin) in serum. In the presence of caffeine/benzoate, Bond-Elut (C8, 200 mg) extracts unconjugated and conjugated bilirubin but not pigments that are covalently bonded to albumin which pass through the column and can be quantitated by a standard diazo method. Following elution from the Bond-Elut column with methanol-acetonitrile (50:50, v/v) unconjugated and conjugated bilirubin can be quantitated either as total pigments or individually by HPLC.

Theophylline in maintenance treatment of chronic asthma: concentration-dependent additional effect to beta 2-agonist therapy.

The effect of long-term treatment with theophylline was studied in 20 chronic asthmatic patients receiving oral and inhaled beta 2-agonists. In a double-blind, randomized cross-over fashion during three consecutive 6-week periods, the patients received theophylline in individually adjusted dosages or placebo to obtain plasma concentrations of 25-45 mumol/l, 50-85 mumol/l and 0, respectively. PEF, beta 2-aerosol consumption, symptom scores and side-effects were recorded daily. The addition of theophylline caused a significant further bronchodilating effect. There was, however, a large interindividual variation in response to additional theophylline and only half of the subjects were responders. Those responding had increased therapeutic efficacy from a steady-state concentration in the range of 50-85 mumol/l compared to the lower concentration. The responders had, on average, more pronounced air-flow obstruction. The incidence of adverse reactions increased with increasing concentrations of theophylline.

Enzymic oxidation of unconjugated bilirubin by rat liver.

The presence of the enzyme bilirubin oxidase, which degrades bilirubin in vitro, was demonstrated in the liver. Subcellular-fractionation experiments indicate that bilirubin oxidase is located in both the inner and outer membranes of the mitochondria. The mean rate of the reaction is 1.57 +/- 0.38 (S.D.) nmol of bilirubin degraded/min per mg of mitochondrial protein (munits/mg of protein). With respect to the overall breakdown of bilirubin, the enzyme has a Km' of 136 microM-bilirubin and a Vmax.' of 9.13 munits/mg of protein. Its activity is influenced by the ionic strength of the media and is inhibited by KCN, thiol reagents, NADH and albumin. The enzyme is aerobic, and between 1 and 1.5 mol of O2 are consumed per mol of bilirubin degraded. The products of the reaction include propentdyopents. The hepatic bilirubin oxidase activity of the jaundiced Gunn-rat liver is not significantly different from that of the Sprague-Dawley rat, and it is not induced by beta-naphthoflavone.

Comparison of theophylline and theobromine metabolism in man.

The total plasma and partial metabolic and renal clearances of theobromine and theophylline were determined in 13 healthy volunteers. Total plasma clearance for theobromine was 46% greater than that for theophylline, but the unbound clearances were almost identical. Theobromine renal clearance was 67% greater than that for theophylline but most of the difference was due to the lower protein binding of theobromine (free fraction = 0.86 compared to 0.58 for theophylline). Clearance by N-demethylation at the 3-position was 3.7-fold higher (unbound clearance 2.5-fold higher) for theobromine than for theophylline, showing that the position of the other methyl substituent (positions 1 or 7) is a major determinant of metabolic rate. There was a high degree of correlation between theophylline and theobromine plasma clearances (r = 0.86) and also between partial metabolic clearances both within drugs and across drugs (r = 0.65-0.99). The renal clearances of theophylline and theobromine were also correlated (r = 0.71). The results support the view that theophylline and theobromine are metabolized by a common group of cytochromes P-450 under similar regulatory control. Theobromine is a good model compound for assessing the activity of these enzymes in man as it has low pharmacological activity and low protein binding, its total and partial metabolic clearances correlate closely with those of theophylline, and close to 100% of the dose can be recovered as known metabolites.

Effect of prolonged bile duct obstruction in the rat on hepatic transport of bilirubin.

In order to investigate the effect of extra-hepatic biliary obstruction on bilirubin transport, bile flow was re-established after 5, 10, 15 and 28 days when the mean (+/- SEM) plasma bilirubin concentrations of the four groups of five rats were 226 +/- 17.9, 201 +/- 22.4, 178 +/- 8.1 and 145 +/- 3.8 mumol/l, respectively. After 12 h of bile drainage in the conscious animal, the mean plasma bilirubin concentrations of the four groups had decreased by 88, 86, 73 and 46%, respectively. The bile flow rate increased with the duration of the obstruction and was maximal in the 28 day obstructed rats, although the bilirubin output in these animals was significantly less than in the other groups. Histological evidence of biliary obstruction was apparent in the livers of the 5 and 10 day obstructed animals. After 15 days of obstruction cirrhosis developed. In conclusion, the disposal of endogenous bilirubin in the bile duct obstructed rat appears to be influenced by the development of cirrhosis.

Enhancement of the urinary excretion of non-sulphated and sulphated radioactive bile acids by sodium acetate in the bile duct obstructed rat.

The renal clearances of [14C]glycocholate, [14C]taurocholate and [3H]glycochenodeoxycholate-3-sulphate were determined in bile duct obstructed rats. Comparisons of the bile acid clearances with glomerular filtration rates (GFR) indicate that most of the filtered bile acids are reabsorbed. Inhibition studies with p-aminohippurate (PAH) and probenecid suggest that a proportion of the bile acids in urine is secreted. Attempts were made to increase the renal clearance of the bile acids by the administration of pharmacological agents. An infusion of sodium acetate (0.3 mol/l) increased the clearance of the radioactive bile acids and augmented the urinary excretion of endogenous 3 alpha-hydroxy bile acids and reduced their concentration in plasma.

The biliary excretion of sulphated and non-sulphated bile acids and bilirubin in patients with external bile drainage.

The biliary excretion of total bilirubin and bile acids, and the fate of tracer doses of radioactive sulphated and non-sulphated bile acids, were studied in patients with percutaneous transhepatic bile drainage. Non-sulphated bile acids were excreted in bile early after biliary decompression, and the serum total 3 alpha-hydroxy bile acid concentrations fell rapidly to normal. Biliary bilirubin excretion was both less than and delayed compared with that of bile acids, and the serum bilirubin concentration fell more slowly. The serum disappearance of [3H]chenodeoxycholate-3-sulphate was slower than that of [14C]glycocholate in all patients with bile drainage, the difference being more marked in the jaundiced patients. The radioactive sulphated bile acids were recovered predominantly in the urine of the jaundiced patients. In contrast [14C]glycocholate was excreted almost exclusively in bile. In an anicteric patient, radioactive sulphated bile acid disappeared from the serum more quickly, and biliary recovery exceeded that in the urine. The studies demonstrate the differences in handling of total bilirubin, and sulphated and non-sulphated bile acids in man after the relief of bile duct obstruction. The biliary excretion of radioactive labelled sulphated bile acids is low for at least 1 week after biliary drainage, but later becomes the predominant route for excretion in the anicteric patient.

Prolonged bile duct obstruction: a new experimental model for cirrhosis in the rat.

Hepatic morphological abnormalities were examined in rats whose bile ducts had been either cannulated and then obstructed or irreversibly ligated for 5, 10, 15 and 28 days or longer. Throughout the experiment most of the morphological changes observed in the cannulated group were comparable to those in the ligated group. Portal inflammation and marginal bile duct proliferation were noted with the same frequency in both groups. Biliary obstruction for 15 days or more led to cirrhosis. After 28 days obstruction, five out of six cannulated rats and four out of six ligated animals respectively developed cirrhosis. The development of cirrhosis was progressive and associated with ascites. It is concluded that in the rat the morphological sequelae of long term cholestasis induced by either cannulation and obstruction or ligation of bile ducts are similar and are accompanied by cirrhosis. The advantages of this experimental model for the study of human cirrhosis are discussed.

Hepatic transport of sulfated and nonsulfated bile acids in the rat following relief of bile duct obstruction.

The effect of bile duct ligation for 5 days on the hepatic transport of sulfated and nonsulfated bile acids was studied. Tracer doses of radioactive bile acids [3H]taurochenodeoxycholate-3-sulfate [3H]chenodeoxycholate-3-sulfate, [3H]taurochenodeoxycholic acid and [14C]taurocholic acid were injected 90 min after relief of obstruction when the plasma total bile acid concentration had reverted to normal. Plasma clearance and biliary excretion of sulfated bile acids were lower than those of nonsulfated bile acids, particularly in the cholestatic rats (p less than 0.02). For each bile acid, hepatic transport in the cholestatic rats was significantly reduced compared with the control rats. [3H]Chenodeoxycholate-3-sulfate and [3H]taurochenodeoxycholic acid were partially metabolized to [3H]taurochenodeoxycholate-3-sulfate prior to biliary excretion. This data suggests that the hepatic transport system for sulfated bile acids is less efficient and more easily impaired by cholestasis than that for nonsulfated bile acids.