Oxidant-antioxidant status in the blood of horses with symptomatic recurrent airway obstruction (RAO).

BACKGROUND: Systemic oxidative stress in horses with recurrent airway obstruction (RAO) is poorly characterized. OBJECTIVES: The goal of this study was to investigate whether equine RAO is associated with systemic disturbances in the oxidant-antioxidant equilibrium. ANIMALS: Seven healthy horses and 7 horses with symptomatic RAO. METHODS: A prospective study. Healthy and RAO-affected horses were exposed to a 48-hour challenge with moldy hay and straw to induce clinical exacerbation of RAO. Venous blood was collected and the activities of the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in equine erythrocyte lysates were measured. The concentration of thiobarbituric acid-reactive substances (TBARSs) was assessed both in erythrocyte lysates and in plasma. RESULTS: A significant increase in the activities of GPx and SOD was detected in RAO-affected horses compared with the control animals. There was no significant difference between groups in terms of the erythrocyte lysate activities of CAT, GR, or TBARs or the plasma concentration of TBARs. CONCLUSION AND CLINICAL IMPORTANCE: Our results support the hypothesis that RAO in horses is associated with systemic oxidative stress. Future studies are needed to assess whether horses suffering from RAO can benefit from antioxidant supplementation.

Analysis of soluble CD14 and its use as a biomarker in neonatal foals with septicemia and horses with recurrent airway obstruction.

Soluble CD14 (sCD14) binds bacterial lipopolysaccharide (LPS) and acts as an anti-inflammatory LPS-inhibitor in vivo. In humans, sCD14 is one of the soluble biomarkers used for various inflammatory diseases and conditions, however, sCD14 assays have not yet been evaluated in horses. Here, we developed and optimized a bead-based assay for the quantification of sCD14 in horses. The assay was then used to determine native sCD14 concentrations in serum from healthy and septic foals, in the colostrum of healthy mares and in plasma from adult horses with recurrent airway obstruction (RAO) and control horses. Healthy foals and adult horses had sCD14 concentrations in serum or plasma in the high ng/ml range. The concentration of sCD14 in colostrum samples from healthy mares was in the µg/ml range. Foals with septicemia and adult horses with RAO had significantly higher sCD14 concentrations in their circulation than the respective control groups. The findings suggest that sCD14 can become a valuable biomarker for neonatal septicemia, RAO and possibly also for other inflammatory diseases in horses. Further studies and larger samples numbers are required to determine normal sCD14 concentration ranges and those that are indicative of disease progression, severity or prognosis.

[Salbutamol improves diaphragmatic contractility in chronic airway obstruction]. / El salbutamol mejora la contractilidad diafragmática en la obstrucción crónica de la vía aérea.

INTRODUCTION: Chronic airflow obstruction in conditions such as chronic obstructive pulmonary disease is associated with respiratory muscle dysfunction. Our aim was to study the effects of salbutamol-a beta-adrenergic agonist known to improve muscle strength in physiologic and pathologic conditions-on diaphragm contractility in an animal model of chronic airway obstruction achieved by tracheal banding. MATERIALS AND METHODS: Twenty-four Sprague-Dawley rats were randomized into a control group and 3 tracheal banding groups, 1 that received acute salbutamol treatment, 1 that received chronic salbutamol treatment, and 1 that received nothing. Arterial blood gases, acid-base balance, and in vitro diaphragmatic contractility were evaluated by measuring peak twitch tension, contraction time, contraction velocity, half-relaxation time, relaxation velocity, and force-frequency curves. RESULTS: The 3 study groups had significantly reduced arterial pH and increased PaCO2 and bicarbonate levels compared to the control group (P<.05). The untreated tracheal banding group had significantly reduced peak twitch tension and contraction velocity, and a significantly lower force-frequency curve in comparison with the other groups (P<.05). The chronic treatment group had a higher relaxation velocity than the untreated study group (P<.05). The mean (SE) peak twitch tension values were 6.46 (0.90)N/cm(2) for the control group, 3.28 (0.55)N/cm(2) for the untreated tracheal banding group, 6.18 (0.71)N/cm(2) for the acute treatment group, and 7.09 (0.59)N/cm(2) for the chronic treatment group. CONCLUSIONS: Diaphragmatic dysfunction associated with chronic airflow obstruction improves with both the acute and chronic administration of salbutamol. The mechanisms involved in respiratory muscle dysfunction warrant further study.

[Arterial blood gas changes in patients with malignant airway obstruction treated with Nd-YAG laser under local anesthesia].

The purpose of this report is to observe the changes in arterial blood gas in patients with malignant airway obstruction treated with Nd-YAG laser under local anesthesia. Nine inoperable lung cancers (7 primary, 2 metastatic) with tracheal and/or bronchial obstruction were studied. Recanalization of the obstructing airway was the goal of Nd-YAG laser treatment. Arterial blood gas levels were measured at rest, post-bronchoscopy, during treatment with Nd-YAG laser, immediately after treatment, and at each hour post-treatment for 5 hours. Blood samples were obtained from a cannula that had already been inserted into the radial artery. A significant decrease in PaCO2 levels was noted after bronchoscopy (12.1 +/- 7.47 mmHg, p less than 0.005), during laser phot resection (16.9 +/- 6.37 mmHg, p less than 0.001), immediately (17.7 +/- 8.51 mmHg, p less than 0.001) and at 1 hour (12.4 +/- 14.01 mmHg, p less than 0.05) after the Nd-YAG laser treatment. No significant changes (p greater than 0.05) in PaCO2 levels were found at 2, 3, 4, 5 hours after treatment. Both PaCO2 and PH showed no significant changes during the process. Because of the marked decline in PaCO2 during and after the Nd-YAG laser treatment, it is suggested that oxygen supplementation should be considered, particularly in hypoxemic patients.