Hydrogen peroxide and nitrite reduction in exhaled breath condensate of COPD patients.

Chronic obstructive pulmonary disease (COPD) is predominantly the result of years of cigarette smoking. Increased oxidative stress in COPD derives from the increased burden of inhaled oxidants (cigarette smoke), air pollution and the increase in reactive oxygen and nitrogen species (ROS and RNS), generated by some inflammatory, immune, and structural airways cells. In view of the lack of therapy that might inhibit the progress of the disease, there is an urgent need for a successful therapeutic approach. Apocynin is a molecule inhibiting activation of NADPH oxidase - enzyme generating ROS and RNS precursor. Thus, our aim was to analyze apocynin influence on hydrogen peroxide and nitrite concentrations in EBC of COPD patients. Apocynin reduced concentration of H(2)O(2) in COPD patients 60 and 120 min after apocynin inhalation, in comparison to placebo (0.43 µM vs. 0.59 µM, and 0.4 µM vs. 0.59 µM respectively, p < 0.05). Moreover, apocynin decreased NO(2)(-) ions concentration in airways of COPD patients after apocynin nebulization (3.97 µM vs. 4.48 µM after 30 min, 3.82 µM vs. 4.48 µM after 60 min, and 3.76 µM vs. 4.48 µM after 30 min respectively, p < 0.05). No adverse effects have been observed. The results suggest that apocynin might be considered as anti-inflammatory agent, and, possibly used in therapy of COPD.

Apocynin reduces reactive oxygen species concentrations in exhaled breath condensate in asthmatics.

Asthma is an inflammatory airway disease, and oxidative stress was proven to be involved in its pathogenesis. Apocynin effectively inhibits the main source of reactive oxygen species (ROS)-nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-by blocking its activation. The aim of this study was to investigate the effect of inhaled apocynin on ROS and RNS (reactive nitrogen species) concentration in 14 nonsmoking mild asthmatics. Effects of nebulized apocynin (0.5 mg/mL) were assessed in exhaled breath condensate (EBC) after 30, 60, and 120 minutes, and safety parameters have been analyzed. Apocynin significantly decreased H2O2 concentration in EBC in comparison with placebo after 60 and 120 minutes. Moreover, apocynin significantly reduced NO(-2) concentration 30 and 60 minutes after nebulization and caused a significant decrease of NO(-3) concentration in EBC 60 and 120 minutes after administration, comparing with placebo. No adverse events have been observed throughout the study. This research confirmed anti-inflammatory properties of nebulized apocynin, which might be an effective and safe drug in bronchial asthma.

Apocynin decreases hydrogen peroxide and nitrate concentrations in exhaled breath in healthy subjects.

The imbalance between reactive oxygen species (ROS) synthesis and antioxidants might be involved in the pathogenesis of many inflammatory diseases. NADPH oxidase, an enzyme responsible for ROS production, may represent an attractive therapeutic target to inhibit, for the treatment of these diseases. Apocynin is an inhibitor of activation of NADPH oxidase complex present in the inflammatory cells. In double blind, placebo-controlled, cross-over study, we investigated the effect of nebulized apocynin on ROS synthesis in 10 nonsmoking healthy volunteers. Apocynin (6ml of 0.5mg/ml) was administered by nebulization and its effects on H(2)O(2), NO(2)(-) and NO(3)(-) generation were assessed after 30, 60 and 120min by collecting exhaled breath condensate (EBC) samples using an EcoScreen analyzer. Additionally, respiratory parameters have been evaluated, utilizing spirometry and DLCO. We also analyzed peripheral blood differential counts and NO(2)(-) serum level, cough scale control and blood pressure as safety parameters. Apocynin caused reduction of H(2)O(2) concentration in EBC as compared to placebo, after 60min. of inhalation (0.18microM vs. 0.31microM, p<0.05) as well as after 120min. (0.2microM vs. 0.31microM, p<0.05). Similarly, apocynin significantly decreased concentration of NO(3)(-) as compared to placebo, after 60 and 120min. (6.8microM vs. 14.4microM and 6.5microM vs. 14.9microM respectively, p<0.05). Apocynin was well tolerated and no adverse events have been observed throughout the study. Thus, as apocynin significantly influence ROS concentration, it might have also antiinflammatory properties. As it is safe, it may have a potential to become a drug in airway inflammatory diseases treatment.

Increased exhaled H2O2 and impaired lung function in patients undergoing bioincompatible hemodialysis.

BACKGROUND: Chronic renal failure (CRF) and hemodialysis (HD) accumulate an inflammatory milieu, contributing to increased systemic and airway oxidative stress that may lead to lung damage. OBJECTIVES: This study was designed to assess exhaled hydrogen peroxide (H2O2), lung function and whole blood chemiluminescence in HD and CRF patients and healthy controls. METHODS: The study included 59 patients (Polyamide STM or Hemophan membranes--19, cuprophane--16, hemodiafiltration--14, continuous ambulatory peritoneal dialysis--10), 16 CRF and 16 healthy controls. The assessment of lung function included FVC (forced vital capacity), FEV1 (forced expiratory volume in the first second) and DLCOc (single breath CO diffusing capacity). Exhaled H2O2 was determined fluorometrically and resting and n-formyl-methionyl-leucyl-phenylalanine (fMLP) luminol-dependent whole blood chemiluminescence (LBCL) were measured simultaneously. RESULTS: Only cuprophane HD patients presented decreased lung function (FVC 63.8+/-17.4%, FEV1 55.9+/-20.3 and DLCOc 72.1+/- 9.3 % of predicted; p<0.05 vs. controls). These patients exhaled the highest H2O2 levels in comparison to CRF (p<0.01): median 0.36 microM (range R: 0.09-0.56 microM) and controls (p<0.05): 0.17 microM (0.2-17.8 microM). These levels were not decreased during the HD session: preHD 1.25 microM (0.2-16.5 microM) and postHD 1.3 microM (0.2-17.8 microM). As a marker of systemic oxidative stress, fMLP-induced LBCL (total light emission) was increased in these patients (1570.6 aUxs/10(4) phagocytes; R: 274.2-8598.9) and in the CRF group (2389.4 aUxs /10(4) phagocytes; R: 491.5- 6184; p<0.05 vs. controls). Other patient groups did not express elevated LBCL and revealed decreased exhaled H2O2 after a session. CONCLUSIONS: An increased oxidative burden in the lungs may contribute to functional lung impairment in patients dialyzed with a cellulose membrane. Biocompatible dialysis with other modalities might reduce airway-borne oxidative stress and is not related with lung damage.

A novel sulfonylurea receptor family member expressed in the embryonic Drosophila dorsal vessel and tracheal system.

Sulfonylurea receptors (SURx) are required subunits of the ATP-sensitive potassium channel. SURx alone is electrophysiologically inert. However, when SURx is combined with an inward rectifier Kir6.2 subunit, ATP-sensitive potassium channel activity is generated. We report the identification, characterization, and localization of Dsur, a novel Drosophila gene that is highly related to the vertebrate SUR family. The Dsur coding sequence contains structural features characteristic of the ABC transporter family and, in addition, harbors 1.7 kilobases of a distinctive sequence that does not share homology with any known gene. When Dsur alone is expressed in Xenopus oocytes glibenclamide-sensitive potassium channel activity occurs. During Drosophila embryogenesis, the Dsur gene is specifically expressed in the developing tracheal system and dorsal vessel. Studies of the Drosophila genome support that only a single Dsur gene is present. Our data reveal conservation of glibenclamide-sensitive potassium channels in Drosophila and suggest that Dsur may play an important role during Drosophila embryogenesis. The lack of gene duplication in the Drosophila system provides a unique opportunity for functional studies of SUR using a genetic approach.

Comparison of the Seralyzer and EMIT systems for determination of theophylline concentrations.

A reflectance photometry assay for measurement of serum theophylline concentration was evaluated by comparison with an enzyme-multiplied immunoassay technique (EMIT). The concentration of theophylline in blood samples obtained from patients receiving intravenous theophylline therapy in the pediatric intensive-care unit was measured by both the Seralyzer and the EMIT systems. The interday and intraday variability of each method were also determined by means of calibrators of known concentration (5 to 40 micrograms/mL). There was significant correlation between the serum theophylline concentrations determined by the Seralyzer system and the EMIT system. The overall standard error of the estimate was 2.3 micrograms/mL, but with operator experience this improved to 1.3 micrograms/mL. Intraday variability was 1.2 micrograms/mL for the Seralyzer and 0.7 micrograms/mL for EMIT; the respective values for interday variability were 1.4 micrograms/mL and 0.8 micrograms/mL. The Seralyzer method measures theophylline concentrations with reliability, convenience, and speed. It could be potentially useful in a satellite, clinic, or acute-care pharmacy area.

Reye syndrome and juvenile rheumatoid arthritis in Michigan.

Reye syndrome (RS) is believed to occur infrequently among children receiving long-term aspirin therapy. We reviewed all cases of RS reported to the Michigan Department of Public Health during 1982 and 1983. Three of the 36 patients were receiving aspirin for the treatment of juvenile rheumatoid arthritis. All three patients had clinical courses characteristic of RS and two had supportive histologic findings on liver biopsy. The incidence of RS among children with juvenile rheumatoid arthritis is significantly greater than the incidence of RS among children who do not have juvenile rheumatoid arthritis. These findings support previous studies that showed that the use of aspirin during the antecedent illness may be a risk factor for the development of RS. Physicians should be aware of the potential for the development of RS among children who are receiving long-term aspirin therapy for the treatment of systemic inflammatory illnesses.