NaHS induces relaxation response in prostaglandin F-2 alpha precontracted bovine retinal arteries partially via K-v and K-ir channels

Hydrogen sulphide (H2S) is known to be produced endogenously in ocular tissues with the highest levels in the retina and cornea. However, it is yet unclear whether it can modulate retinal arterial tone. Herein, we aimed to investigate the effectiveness and the mechanism of the action of H2S in the isolated bovine retinal arteries. For this purpose, the probable vasorelaxant and inhibitory effects of H2S on vascular reactivity were tested comparatively in the retinal arteries by using the donor, sodium hydrosulphide (NaHS). Thereafter, in relation to the mechanism of action of H2S, the role of nitric oxide (NO) and endothelial vasodilators of cyclooxygenase pathway as well as ATP-sensitive potassium channel (K-ATP), voltage-dependent potassium channel (K-v), calcium-activated potassium channel (K-Ca(++)), inwardly rectifying potassium channel (K-ir), L-type voltage-dependent calcium channel and adenylate cyclase pathway were evaluated. NaHS (1 mu M-3 mM) displayed prominent relaxations over the concentrations of 300 mu M in both PGF(2 alpha) and K+ precontracted retinal arteries. Comparatively, in the presence of NaHS (3 mM) pretreatment, the maximum contractile responses and pEC(50) values to PGF(2 alpha) and K+ were significantly reduced as well. Neither the presence of the known inhibitors of NO synthase, guanylate cyclase, cyclooxygenase, adenylate cyclase, KA(ATP) and K-Ca(++) type K+ channels, and L-type voltage-dependent calcium channels nor the removal of endothelium, modified the relaxation response to NaHS in retinal arteries. However, a remarkable decrease was observed in the presence of the inhibitors of K-v or K-ir type K+ channels. In addition, administration of L-cysteine (1 mu M-3 mM), the precursor of H2S, induced a modest relaxation response in PGF(2 alpha) precontracted retinal arteries, which was significantly decreased in the presence of cystathionine-beta-synthase (CBS) inhibitor, aminooxyacetic acid, but was unmodified in the presence of the cystathionine-gamma-Iyase (CSE) inhibitor, DL-propargylglycine or the deendothelization of retinal arteries. Our findings suggested that H2S might play a substantial role in the regulation of retinal arterial tone possibly by acting on K-v and K-ir channels. (C) 2015 Elsevier Ltd. All rights reserved

Immunization status in chronic obstructive pulmonary disease: A multicenter study from Turkey

OBJECTIVE: The purpose of this study is to detect the prevalence and the factors associated with influenza and pneumococcal vaccination and outcomes of vaccination during 2013-2014 season in patients with chronic obstructive pulmonary disease (COPD) in Turkey

Immunization status in chronic obstructive pulmonary disease: A multicenter study from Turkey

OBJECTIVE: The purpose of this study is to detect the prevalence and the factors associated with influenza and pneumococcal vaccination and outcomes of vaccination during 2013-2014 season in patients with chronic obstructive pulmonary disease (COPD) in Turkey. METHODS: This was a multicenter retrospective cohort study performed in 53 different centers in Turkey. RESULTS: During the study period, 4968 patients were included. COPD was staged as GOLD 1-2-3-4 in 9.0\%, 42.8\%, 35.0\%, and 13.2\% of the patients, respectively. Influenza vaccination rate in the previous year was 37.9\%; and pneumococcus vaccination rate, at least once during in a life time, was 13.3\%. Patients with older age, higher level of education, more severe COPD, and comorbidities, ex-smokers, and patients residing in urban areas had higher rates of influenza vaccination. Multivariate logistic regression analysis showed that advanced age, higher education levels, presence of comorbidities, higher COPD stages, and exacerbation rates were associated with both influenza and pneumococcal vaccination. The number of annual physician/outpatient visits and hospitalizations due to COPD exacerbation was 2.73 +/- 2.85 and 0.92 +/- 1.58 per year, respectively. Patients with older age, lower education levels, more severe COPD, comorbid diseases, and lower body mass index and patients who are male and are residing in rural areas and vaccinated for influenza had significantly higher rates of COPD exacerbation. CONCLUSIONS: The rates of influenza and pneumococcal vaccination in COPD patients were quite low, and the number of annual physician/outpatient visits and hospitalizations due to COPD exacerbation was high in Turkey. Advanced age, higher education levels, comorbidities, and higher COPD stages were associated with both influenza and pneumococcal vaccination