Monoclonal antibody-directed analysis of cytochrome P-450-dependent monooxygenases and mutagen activation in the livers of DBA/2 and C57BL/6 mice.

Monoclonal antibodies (MAb 1-7-1 and Mab 2-66-3) specific for cytochrome P-450 (cyt. P-450) isozymes inhibited the metabolism of carcinogens, other xenobiotics, and endogenous compounds in two strains of mice. Postmitochondrial liver supernatant (S9) was prepared from untreated, 3-methylcholanthrene-treated, phenobarbital-treated, and pregnenolone 16 alpha-carbonitrile-treated C57BL/6 (B6) and DBA/2 (D2) mice. The modifying effect of two types of MAb to a 3-methylcholanthrene-induced cyt. P-450 and a phenobarbital-induced cyt. P-450 was investigated for: (a) S9-mediated mutagenicity of aflatoxin B1, benzo(a)pyrene 7,8-dihydrodiol, 2-acetylaminofluorene, and N-nitrosomorpholine in Salmonella typhimurium strains; and (b) the activity of aryl hydrocarbon hydroxylase, ethoxycoumarin O-deethylase, ethoxyresorufin O-deethylase, aminopyrine N-demethylase, and testosterone 6 beta-, 7 alpha-, and 16 beta-hydroxylases. With certain S9s, MAb-1-7-1 inhibited only those cytochrome P-450 isozymes involved predominantly in activity of aryl hydrocarbon hydroxylase, ethoxyresorufin O-deethylase, and ethoxycoumarin O-deethylase and mutagenicity of 2-acetylaminofluorene and benzo(a)pyrene 7,8-dihydrodiol; MAb 2-66-3 inhibited only those involved in aminopyrine N-demethylase and testosterone 6 beta-, 7 alpha, and 16 beta-hydroxylase activity and aflatoxin B1 mutagenicity. Both Mab 1-7-1 and MAb 2-66-3 inhibited cytochrome P-450 isozyme(s) implicated predominantly in testosterone 7 alpha-hydroxylation in S9 from pregnenolone 16 alpha-carbonitrile-treated B6 mice. MAb 1-7-1 did not inhibit N-nitrosomorpholine mutagenicity and MAb 2-66-3 increased it by 2- to 6-fold depending on the source of S9. Using these MAbs, it is thus possible to identify the contribution of the epitope-defined single or class of cyt. P-450 to specific metabolic reactions in S9 from untreated and inducer-treated mice.

Long-lasting effects of tobacco smoking on pulmonary drug-metabolizing enzymes: a case-control study on lung cancer patients.

Lung tissue specimens were taken during surgery from middle-aged men with either lung cancer (LC, n = 54) or a nonneoplastic lung disease (n = 20). Aryl hydrocarbon hydroxylase (AHH), 7-ethoxycoumarin O-deethylase (ECDE), epoxide hydrolase (EH), glutathione S-transferase (GST), and UDP-glucuronosyltransferase (UDPGT) activities and glutathione and malondialdehyde contents were determined in 12,000 X g supernatant fractions from nontumorous parenchymal tissues. Interindividual differences in enzyme activities ranged from 11- to 440-fold, and glutathione content varied by 17-fold; the values showed unimodal distributions. AHH, ECDE, EH, and UDPGT activities were significantly and positively correlated to each other; a significant negative correlation was found between GST and the other enzymes. A relationship between enzyme activity and number of cigarettes smoked (pack-years) was found only for GST. Ignoring detailed smoking histories in the 6-month period preceding surgery, no difference was found in enzyme activities or glutathione content between LC and nonneoplastic lung disease patients or between smokers and nonsmokers. However, when the number of days since stopping smoking was considered, in smokers a significant increase was found for AHH, EH, and UDPGT activities and a significant decrease was found for GST activity, as compared to nonsmokers. LC patients who had smoked until the day before surgery had higher activities of AHH, ECDE, EH, and UDPGT than nonsmokers, while GST activity was reduced by one-third. The activities of these enzymes returned to the basal level found in nonsmokers within 59 (AHH), 108 (EH), 67 (UDPGT), and 40 (GST) days. LC patients who were recent smokers (within 30 days prior to surgery) had significantly induced AHH and ECDE activities when compared with smoking nonneoplastic lung disease patients. These results show that pulmonary drug metabolism can be altered by tobacco smoking and that these effects can last 40 to 108 days after cessation of smoking. These new findings should be considered in studies on the role of carcinogen-metabolizing enzymes in determining susceptibility to lung cancer.

Metabolic polymorphism affecting DNA binding and excretion of carcinogens in humans.

A case-control study on lung cancer patients demonstrated the pronounced effect of tobacco smoke on pulmonary carcinogen metabolism and suggested the existence of a metabolic phenotype at higher risk for tobacco-associated lung cancer. Lung cancer patients who were recent smokers showed in their lungs (i) significantly induced CYP1A1-related enzyme activity vs smoking non-lung cancer patients; (ii) increased benzo(a)pyrene (BP) tetrol formation from BP 7,8-diol by lung microsomes; and (iii) high levels of cytochrome P4501a1 by immunohistochemical staining. Levels of bulky aromatic DNA adducts (by 32P-postlabelling) and of BP-diol-epoxide (BPDE) adducts (by HPC/fluorometry) were quantified in lung parenchyma. Aryl hydrocarbon hydroxylase activity and the level of BPDE-DNA adducts (r = 0.91; p < 0.001) and to a lesser degree bulky DNA adducts were correlated. Thus pulmonary CYP1A1 expression (inducibility) controls in part polycyclic aromatic hydrocarbon-DNA adduct formation in tobacco smokers and, therefore, appears to be associated with lung cancer risk. High risk subjects for lung cancer among smokers may be identifiable through genotyping for polymorphic drug metabolizing enzymes in combination with molecular dosimetry of carcinogen-DNA adducts and mutation analysis in target (surrogate) cells. Such studies in a Finnish cohort of lung cancer patients and controls are in progress. Interim results of the effect of metabolic polymorphism on the level of PAH-DNA adducts and on the excretion of mutagens in urine are summarized.

Diagnosis of polymorphisms in carcinogen-activating and inactivating enzymes and cancer susceptibility--a review.

Up to 90% of all cancers are possibly caused by environmental factors, such as tobacco smoke, diet and occupational exposures. The majority of chemical carcinogens require metabolic activation before they interact with cellular macromolecules and can cause cancer initiation. The xenobiotic-metabolising machinery contains two main types of enzymes: the phase-I cytochromes P-450 (CYP) mediating oxidative metabolism, and phase-II conjugating enzymes. Several phase-I and phase-II genes have recently been cloned and identified in humans. Many of them show polymorphism and have been suggested to contribute to individual cancer susceptibility as genetic modifiers of cancer risk. Altered phenotypes and genotypes in the CYP subfamilies CYP1A1, CYP2D6 and CYP2E1 have been associated with tobacco smoke-induced lung cancer and other cancers. Defective glutathione S-transferase (GST) and N-acetyltransferase (NAT) enzymes have been associated with an increased risk of developing lung and bladder cancer. There are also several studies in each category in which no associations have been found. The risk of developing lung cancer is dramatically (up to 40-fold) elevated in subpopulations having simultaneously high-risk genotypes in CYP1A1 and GSTM1. There are several difficulties in this area of research. First, many of the observed restriction-fragment length polymorphisms (RFLPs) are due to mutations in introns or other silent areas of DNA, raising the possibility that any associations found between RFLPs and cancer occur only by chance. Second, biologically plausible mechanisms linking genotypes and cancer are lacking in most of the observed cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogenic nitrosamines: free radical aspects of their action.

NDMA and other nitrosamines may be activated into DNA binding intermediates by a cytochrome P450-dependent formation of alpha-nitrosamino radicals or photochemically. Within the catalytic site of cytochrome P450, these radical intermediates either combine with HO. to form alpha-hydroxynitrosamines or decompose into nitric oxide and N-methylformaldimine. In the presence of phosphate, nutagenic alpha-phosphonooxy derivatives are formed from radicals generated chemically/photochemically. Studies on lipid peroxidation, in vivo and in vitro, have further suggested that radicals are formed as intermediates from N-nitrosodialkylamines. The level of nitrosamine-induced lipid peroxidation parallels hepatocarcinogenicity in rats. These data, although preliminary, provide further evidence that free radical damage and DNA alkylation are involved in carcinogenesis induced by nitrosamines.

A molecular and epidemiological study on bladder cancer: p53 mutations, tobacco smoking, and occupational exposure to asbestos.

In this study, we found an unexpected association (crude odds ratio = 2.8; 95% confidence interval = 0.9-8.4) between definite work-related exposure to asbestos and carcinoma of the urinary bladder in a small group of patients (n = 28) initially recruited as referents for an epidemiological feasibility study on the occupational causes of lung cancer. We extended the study by using molecular methods to examine mutations in the p53 tumor suppressor gene in the same cases of bladder cancers. The same number of archival samples of transitional cell carcinoma, mainly of grade 3, were added to the analysis. We failed to show any association between occupational exposure to asbestos and p53 mutations among bladder cancer patients. We observed an increasing occurrence of p53 mutations in nonsmokers (5 of 17, 29%), former smokers (8 of 21, 38%), and current smokers (9 of 16, 56%) in that order; however, this was not statistically significant. The most prevalent type of mutation was G:C to A:T transition. Tumor grade was not associated with the frequency of mutations, but the higher stage (T3-T4) tumors appeared to have mutations more frequently than did the less invasive tumors (T1-T2).

Activities of antioxidant enzymes and lipid peroxidation in endometrial cancer.

Antioxidant enzyme activities and lipid peroxidation were analysed in normal endometrium and endometrial cancer tissues from Finnish and Japanese patients. The catalase and glutathione peroxidase activities of normal endometrium were significantly lower in Finns than in Japanese. Lipid peroxidation was slightly higher in endometrial cancer as compared with normal endometrium both in the Finns and in the Japanese. When cancer tissues were compared with normal endometrium both in Finns and Japanese the activity of superoxide dismutase was significantly lower in cancer tissue than in normal endometrium. In Finns glutathione S-transferase activity was also lower in endometrial cancer tissue than in normal endometrium, and a similar tendency was also found in Japanese. This study suggests that endometrial cancer tissue is associated with an impaired enzymic antioxidant defence system.

Lipid peroxidation status, somatic mutations and micronuclei in peripheral lymphocytes: a case observation on a possible interrelationship.

A controlled dietary study was conducted in healthy female volunteers and reported elsewhere [1]. In a subset of samples four different biomarkers were analyzed: plasma malondialdehyde (MDA) levels and urinary 8-isoprostaglandin-F(2alpha) were measured as markers for lipid peroxidation. The frequency of hprt (hypoxanthine guanine phosphoribosyl transferase) mutants and micronuclei in peripheral blood lymphocytes were analyzed as indicators of genotoxic effects. One of the ten individuals showed extremely high background levels in all of the four endpoints measured. This case observation raises the possibility that life style factors and dietary habits affect the level of DNA reactive lipid peroxidation products, which in turn increase mutagenic and cytogenetic effects. A possible association between these biomarkers, particularly in relation to dietary fat intake and antioxidant status, should now be studied in a larger trial.

Monoclonal antibody-directed characterization of benzene, ethoxyresorufin and pentoxyresorufin metabolism in rat liver microsomes.

The contribution of cytochrome P450IA, P450IIB, P450IICII and P450IIEI to the oxidative metabolism of benzene, 7-ethoxyresorufin and 7-pentoxyresorufin was investigated using monoclonal antibodies (MAb) in liver microsomes from fed, one-day fasted, phenobarbital (PB)-, 3-methylcholanthrene (MC)- and ethanol-treated rats. Overall catalytic activity varied with different pretreatments and thereby the contribution of different P450s. MAb 1-91-3 against P450IIE1 did not influence alkoxyresorufin dealkylation but inhibited benzene aromatic hydroxylase (BAH) in relation to its increasing inducibility as follows: MC, PB (less than or equal to 48%) less than fed (less than or equal to 59%) less than fasted (less than or equal to 70%) less than ethanol (less than or equal to 91%). MAbs 2-66-3, 4-7-1 and 4-29-5, all against P450IIB, had no effect on 7-ethoxyresorufin O-deethylase (EROD) but inhibited the activities of high-Km BAH (greater than or equal to 58%) and 7-pentoxyresorufin O-depentylase (PROD) (greater than or equal to 96%) in PB-treated microsomes. MAb 1-7-1 against P450IA inhibited EROD (79%), PROD (50%) and high-Km BAH (42%) activities in MC-microsomes. MAb 1-68-11 against P450IIC11 inhibited EROD, PROD and high-Km BAH activities. Thus, P450IIE1 contributed to benzene metabolism as a low-Km BAH but not to alkoxyresorufin metabolism. P450IIB was responsible besides for the major part of 7-pentoxyresorufin metabolism also, selectively, for benzene hydroxylation at high benzene concentrations. P450IA contributed primarily to 7-ethoxyresorufin metabolism and only slightly to PROD and high-Km BAH activities. P450IIC11 contributed slightly to high-Km BAH and to alkoxyresorufin metabolism.

Hypolipidemia and peroxisome proliferation induced by phenoxyacetic acid herbicides in rats.

Male Wistar rats were treated daily by gavage with two phenoxy herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D)(100-200 mg/kg body wt) and 4-chloro-2-methylphenoxyacetic acid (MCPA) (100-200 mg/kg body wt), and with the chemically different glyphosate N-phosphonomethyl glycine (300 mg/kg body wt) 5 days per week for 2 weeks. A hypolipidemic drug, clofibrate [ethyl-2-(4-chlorophenoxy)-2-methylpropionate], which is structurally related to phenoxy acids, was used as a positive control (200 mg/kg body wt). 2,4-D and MCPA had several effects similar to those of clofibrate: all three compounds induced proliferation of hepatic peroxisomes, decreased serum lipid levels, and increased hepatic carnitine acetyltransferase and catalase activities. 2,4-D and MCPA, but not clofibrate, decreased lipoprotein lipase activity in the adipose tissue to about a third of the control value but did not change the lipoprotein lipase activity in the heart muscle. The data suggest that these compounds cause hypolipidemia not by enhancing the storage of peripheral lipids in adipose tissue but by preferentially increasing lipid utilization in the liver. Glyphosate caused no peroxisome proliferation or hypolipidemia, suggesting that these effects are associated with the structural similarity between phenoxy acid herbicides and clofibrate.

Monoclonal antibody characterization of hepatic and extrahepatic cytochrome P-450 activities in rats treated with phenobarbital or methylcholanthrene and fed various cholesterol diets.

Monoclonal antibodies (MAb) against 3-methylcholanthrene (MC)- and phenobarbital (PB)-inducible forms of cytochrome P-450 isozyme were used to characterize changes in aryl hydrocarbon hydroxylase (AHH) and ethoxycoumarin O-deethylase (ECDE) activities modulated by dietary cholesterol. Rats were induced by MC or PB, and immunochemical inhibition of AHH and ECDE activities was studied as an indication of changes in cytochrome P-450 isozyme patterns. Feeding of a cholesterol-free diet markedly decreased enzyme activities both in liver and in small intestinal mucosa, and the highest activities were observed after feeding rats a high (2%)-cholesterol diet for one month. As a control, a normal pelleted diet (0.1% cholesterol) was used; in rats fed this diet, intermediate levels of monooxygenase activities were present. Although no diet-dependent change in total AHH and ECDE activities was observed in kidneys and lungs, diet apparently modulated isozyme composition in the lungs, as indicated by a change in the immunochemical inhibition pattern with MAb; no such shift was observed in the kidneys. In liver and intestine, in addition to changes in total activity, isozyme composition was also altered, as indicated by inhibition of the catalytic activities of cytochrome P-450 by MAb. Our data infer that dietary cholesterol can: (i) modulate total monooxygenase activities, especially in the intestine; (ii) change the cytochrome P-450 isozyme composition in liver and intestine; (iii) change isozyme composition without changing overall enzyme activity, e.g. in lungs; and (iv) have no effect in a tissue (e.g. kidney) that lacks constitutionally the P-450 isozyme responsive to cholesterol.

Monoclonal antibody-directed characterization of cytochrome P450 isozymes responsible for toluene metabolism in rat liver.

Monoclonal antibodies (MAbs) were used to study the contribution of cytochromes P450IA1/IA2, P450IIB1/IIB2, P450IIC11/IIC6 and P450IIE1 to toluene side-chain (benzyl alcohol, BA, formation) and ring (o- and p-cresol formation) oxidation in liver microsomes from fed, one-day fasted, and phenobarbital (PB)-, 3-methylcholanthrene (MC)- and ethanol-treated rats. All rats were fed synthetic liquid diets. MAb 1-7-1 against P450IA1/IA2 inhibited markedly o-cresol formation and slightly p-cresol formation but not BA formation only in microsomes from MC-treated rats. MAbs 2-66-3, 4-7-1 and 4-29-5 against P450IIB1/IIB2 strongly inhibited BA, o-cresol and p-cresol formation only in PB-induced microsomes. MAb 1-68-11 against P450IIC11/IIC6 inhibited BA formation at high toluene concentration in the following order: fed greater than fasted greater than ethanol = MC greater than PB, and ethanol greater than or equal to fed = fasted greater than MC greater than PB on the basis of the percentage and net amount inhibition, respectively. MAb 1-91-3 against P450IIE1 inhibited BA formation at low toluene concentration, but not at high concentration, in the following order: ethanol greater than fasted = fed greater than MC, and ethanol greater than fasted greater than fed greater than MC on the basis of percentage and net inhibition, respectively. MAbs 1-68-11 and 1-91-3 also inhibited p-cresol formation at high and low toluene concentrations, respectively. These results indicate that (i) both P450IIE1 and P450IIC11/IIC6 are constitutive isozymes mainly responsible for the formation of BA and p-cresol from toluene as low- and high-Km isozymes, respectively; (ii) P450IIE1, but not P450IIC11/IIC6, is induced by one-day fasting and ethanol treatment; (iii) both P450IIE1 and P450IIC11/IIC6 are decreased by PB and MC treatments; (iv) P450IIE1 is inhibited by high concentration of toluene; (v) P450IIB1/IIB2 can contribute to the formation of BA, o- and p-cresol from toluene, while P450IAI/IA2 preferentially contributes to the formation of o-cresol.

The role of individual susceptibility in cancer burden related to environmental exposure.

Individual susceptibility to cancer may result from host factors including differences n metabolism, DNA repair, altered expression of protooncogenes and tumor suppressor genes, and nutritional status. Since most carcinogens require metabolic activation before binding to DNA, variations in an individual's metabolic phenotype that have detected in enzymes involved in activation and detoxification should play an essential role in the development of environmental cancer. This phenotypic metabolic variation has now been related to genetic polymorphisms, and many genes encoding carcinogen-metabolizing enzymes have been identified and cloned. Consequently, allelic variants or genetic defects that give rise to the observed variation and new polymorphisms have been recognized. Development of simple polymerase chain reaction (PCR)-based assays has enabled identification of an individual's genotype for a variety of metabolic polymorphisms. Thus, recent knowledge of the genetic basis for individual metabolic variation has opened new possibilities of studies focusing on increased individual susceptibility to environmentally induced cancer, which are reviewed with special reference to smoking-induced lung cancer. Cancer susceptibility due to chemical exposure is likely to be determined by an individual's phenotype for a number of enzymes (both activating and detoxifying) relevant to that of a single carcinogen or mixtures of carcinogens. Given the number and variability in expression of carcinogen-metabolizing enzymes and the complexity of chemical exposures, assessment of a single polymorphic enzyme (genotype) may not be sufficient. Mutations in the p53 gene are among the most common genetic changes in human cancer. The frequency and type p53 mutations can act as a fingerprint of carcinogen exposure and may therefore provide information about external etiological agents, intensity of exposure, and host factors affecting the tumorigenesis process. In human lung cancer, p53 mutations (both the mutation pattern and frequency) have been linked with tobacco smoking; the type of mutation most frequently observed is G:C to T:A transversion, a mutation preferentially induced by benzo[a]pyrene diol epoxide. An association between the presence of this transversion and the genotype deficient in glutathione S-transferase M1-mediated detoxification has been observed in lung cancer. Taken together, these findings suggest that determination of metabolic at risk genotypes in combination with levels of DNA adducts in target (surrogate) tissues and the p53 mutation pattern should allow the identification of susceptible individuals and subgroups in carcinogen-exposed populations.

Interaction between dose and susceptibility to environmental cancer: a short review.

Increased risk of environmentally induced cancer is associated with various types of exposures and host factors, including differences in carcinogen metabolism. Since many carcinogenic compounds require metabolic activation to enable them to react with cellular macromolecules, individual features of carcinogen metabolism may play an essential role in the development of environmental cancer. In this context, cigarette smoking has often been the main type of carcinogenic exposure examined in human studies. Increasing attention has recently been paid to the dose level at which individual susceptibility may be observed. Present studies on increased risk of smoking-related lung cancer associated with phenotypic or genotypic variation of the genes encoding for CYP1A1 or CYP2D6 enzymes are summarized. Similarly, higher risks of lung or bladder cancer seen at various levels of smoking in association with polymorphism of the glutathione S-transferase gene GSTM1 or NAT1 and NAT2 genes involved in N-acetylation are reviewed. Finally, the influence of CYP2E1, GSTM1, or the combined at-risk genotype on the risk of hepatocellular carcinoma in smokers is briefly discussed.

Carcinogen metabolism in human lung tissues and the effect of tobacco smoking: results from a case--control multicenter study on lung cancer patients.

Cigarette smoking is the strongest risk factor for lung cancer, but genetically determined variations in the activities of pulmonary enzyme that metabolize tobacco-derived carcinogens may affect individual risk. To investigate whether these enzymes (e.g., CYP1A-related) can serve as markers for carcinogen-DNA damage, lung tissue specimens were taken during surgery from middle-aged men with either lung cancer or non-neoplastic lung disease. Phase I [aryl hydrocarbon hydroxylase (AHH), ethoxycoumarin O-deethylase (ECOD)] and phase II (epoxide hydrolase, UDP-glucuronosyltransferase, glutathione S-transferase) enzyme activities, glutathione and malondialdehyde contents were determined in lung parenchyma and/or bronchial tissues; some samples were also analyzed for DNA adducts, using 32P-postlabeling. The data were then analyzed for the following: a) differences in metabolic profiles between bronchial and parenchymal lung tissue; b) the effect of recent exposure to tobacco smoke on enzyme inducibility and benzo[a]pyrene metabolism; c) differences in enzyme inducibility between lung cancer and non-lung cancer patients; d) the effect of smoking on metabolism of mutagens in vitro; e) pulmonary DNA adduct levels and AHH activity in lung parenchyma of smokers and ex-smokers; f) lipid peroxidation products in lung tissue from lung cancer and non-lung cancer patients, as related to smoking habits and degree of airway obstruction; and g) prognostic value of AHH pulmonary activity in lung cancer patients. The results demonstrate a pronounced effect of tobacco smoke on pulmonary metabolism of xenobiotics and prooxidant state and suggest the existence of a metabolic phenotype at higher risk for tobacco-associated lung cancer.

Immunohistochemical detection of pulmonary cytochrome P450IA and metabolic activities associated with P450IA1 and P450IA2 isozymes in lung cancer patients.

The main polycyclic aromatic hydrocarbon-inducible cytochrome P450 was studied in lung tissue from 57 lung cancer patients by immunohistochemistry, using a monoclonal antibody (1-7-1) that recognizes P450IA1 and P450IA2 isozymes. The intensity of immunostaining was compared with the pulmonary activity of a P450IA1-dependent enzyme, aryl hydrocarbon hydroxylase (AHH), and with P450IA2-related metabolic activity estimated from the ratio of caffeine metabolites in urine. Immunostaining was not observed in peripheral lung tissue of nonsmokers or ex-smokers but was seen in the bronchiolar and alveolar epithelium of all patients who were smokers and had a peripheral carcinoma (16/16) and of 60% (10/17) of those who had a bronchial carcinoma. AHH activity was positively related to the intensity of immunostaining, and an almost 2-fold increase due to smoking was detected in the ratios of caffeine metabolites. These results demonstrate that tobacco smoke induces P450IA1 in the lung and probably P450IA2 in the liver, and suggest a role for certain metabolic phenotypes of P450IA1 in peripheral pulmonary carcinoma.

Gastroesophageal reflux in asthmatics: A double-blind, placebo-controlled crossover study with omeprazole.

STUDY OBJECTIVES: To investigate the prevalence of gastroesophageal reflux (GER) among patients with asthma and to determine the effect of omeprazole on the outcome of asthma in patients with GER. DESIGN: A double-blind, placebo-controlled crossover study. SETTING: Asthmatic patients who attended the pulmonary outpatient clinic of Turku University Central Hospital, Finland. PATIENTS: One hundred seven asthmatic patients. INTERVENTIONS: The patients who were found to have GER in ambulatory esophageal pH monitoring were randomized to receive either omeprazole, 40 mg qd, or placebo for 8 weeks. After a 2-week washout period, the patients were crossed over to the other treatment. Spirometry was performed at baseline and immediately after both treatment periods. Peak expiratory values, use of sympathomimetics, and pulmonary and gastric symptoms were recorded daily in a diary. RESULTS: Pathologic GER was found in 53% of the asthmatic patients. One third of these patients had no typical reflux symptoms. Daytime pulmonary symptoms did not improve significantly (p = 0.14), but a reduction in nighttime asthma symptoms (p = 0.04) was found during omeprazole treatment. In the patients with intrinsic asthma, there was a decline in [corrected] FEV(1) values (p = 0.049). Based on symptom scores, 35% of the patients were regarded as responders to 8-week omeprazole treatment. The reflux (time [percent] of pH < 4) was found to be more severe (p = 0. 002) in the responders. CONCLUSIONS: There is a high prevalence of GER in the asthmatic population. This reflux is often clinically "silent." After an 8-week omeprazole treatment, there was a reduction in nocturnal asthma symptoms, whereas daytime asthma outcome did not improve. There seems to be a subgroup of asthma patients who benefit from excessive antireflux therapy.

Pulmonary lipid peroxidation in cigarette smokers and lung cancer patients.

Lipid peroxidation (LPO) was studied in lung tissues of patients with lung cancer (LC, n = 37) or nonlung cancer (NLC, n = 13) and its relationships with the smoking habits and the degree of airway obstruction were investigated. Specimens of peripheral lung parenchyma, free of tumor tissue, were taken and the malondialdehyde (MDA) content was measured in the S-12 fractions. Airway obstruction was assessed by flow-volume curves, and data were expressed as percentage of the predicted values. Cigarettes smoked were expressed as pack-years. The patients with LC and NLC did not differ by MDA content, age, and number of pack-years. On the contrary, FEF75-85 and MEF75 were significantly lower in LC than in NLC patients (p less than 0.05). The MDA content was inversely correlated to number of days patients had refrained from smoking (r = -0.66, p less than 0.001). The MDA content was higher in recent smokers (ie, people smoking during the last 30 days before surgery) than in the other patients (0.136 +/- 0.007 vs 0.116 +/- 0.007 mumol/g of tissue, p less than 0.05) and, by considering only recent smokers, MDA content was higher in LC patients (0.144 +/- 0.008 mumol/g of tissue) than in NLC patients (0.113 +/- 0.014 mmol/g tissue, p = 0.059). When patients were divided into "high MDA" and "low MDA" groups, MEF75 was much lower in the high MDA group (35.1 +/- 3.4 percent) than in the low MDA group (55.1 +/- 8.1 percent) (p less than 0.01). These results suggest the following: (1) enhanced level of prooxidant state in the lungs is associated with recent cigarette smoking; (2) LC patients may be more prone than respective NLC patients to oxidative stress; (3) MDA level and degree of small airway obstruction were associated and differed between LC and NLC patients even though these groups did not differ in the percentage of recent smokers; and (4) a common free-radical mediated pathway may be active for both LC and small airway obstruction.

Phospholipids and fatty acids in breast cancer tissue.

The fatty acid composition of fractionated phospholipids and neutral lipids was analyzed in human breast cancer tissues and the surrounding, apparently healthy tissue. In the cancer tissues the relative amounts of unsaturated fatty acids were increased in all the phospholipid subclasses analyzed. The differences were more marked in phosphatidylethanolamine than in the other phospholipid fractions and, furthermore, the relative amount of phosphatidyl-ethanolamine was increased in cancerous tissue. In blood-erythrocyte phospholipids, no differences in fatty acid composition could be found between breast cancer and control patients. The present study suggests that the lipid composition of cancerous breast tissues differs from that of the surrounding tissue and may be involved in carcinogenesis.

Little effect of ordinary antihypertensive therapy on nocturnal high blood pressure in patients with sleep disordered breathing.

The antihypertensive effects of four different antihypertensive medications (beta-blocking agent, atenolol 50 mg; calcium-antagonist, isradipine SRO [slow release] 2.5 mg; diuretic, hydrochlorothiazide [HCTZ] 25 mg; and angiotension converting enzyme-inhibitor, spirapril 6 mg) on obese patients with sleep disordered breathing and hypertension were compared by the ambulatory blood pressure measurement (ABPM). Eighteen patients were randomized in a double-blind, crossover fashion to receive each of the four different medications for 8 weeks. ABPM was performed at baseline and after an 8-week treatment with these medications. A 2- to 3-week washout period occurred both at baseline and between each of the four medications. Three patients were omitted from statistical analysis because of technical problems of ABPM. Atenolol, isradipine SRO, and spirapril decreased significantly (P < .01) the mean 24-h systolic blood pressure, whereas HCTZ did not. The mean 24-h diastolic blood pressure decreased significantly after all four medications: 12 (SD+/-14) mm Hg with atenolol, 7 (SD+/-10) mm Hg with isradipine SRO, 3 mm Hg (SD+/-14) with HCTZ, and 6 (SD+/-15) mm Hg with spirapril (P < .01). During nighttime none of the medications reduced the mean diastolic or systolic blood pressure significantly. According to the 24-h blood pressure curve the influence of these four medications during the whole measurement period was not similar. Atenolol and spirapril lost their antihypertensive effect during the early morning hours. The antihypertensive effect of HCTZ varied markedly from hour to hour. The trough-to-peak ratio of no medication was >0.50. Negative correlation was observed between the apnea time and the mean systolic 24-h (r = -0.604, P = NS) and the mean systolic nocturnal blood pressure change (r = -0.590, P = NS). Our study revealed that the daytime high blood pressure was quite easily controlled by the ordinary monotherapy in these patients with partial upper airway obstruction and hypertension. Instead none of the medications used decreased nocturnal high blood pressure markedly.