RESUMO
UNLABELLED: Multi-detector computed tomography (MDCT) is most commonly used for staging of non-small cell lung cancer (NSCLC). In recent years, 18F- fluorodeoxyglucose positron emission tomography combined with computed tomography (18F-FDG PET/CT) has also been used for the same purpose. Since studies comparing these two methods are scarce, our aim was to determine how the TNM classification and thereby staging of NSCLC compare between 18F-FDG PET/CT and MDCT. 18F-FDG PET/CT and MDCT were collected in 83 patients with NSCLC 3 to 30 days apart (median 17 days). The investigators interpreting 18F-FDG PET/CT were unaware of MDCT results. The Cohen's kappa (κ) was calculated to determine the rate of agreement. The hypothesis was that the strength of agreement between the two methods will be at least moderate (κ>0.40) based on the adopted criteria (κ<0.20 poor; 0.21-0.40 fair; 0.41-0.60 moderate; 0.61-0.80 good; 0.81-1.00 very good agreement). The agreement was moderate for determining the T class (κ=0.45, overall agreement 58%), poor for the N class (κ=0.13, 42%) and fair for the M class (κ=0.22, 58%). The agreement for overall staging of NSCLC was poor (κ=0.20, 45%). The major source of disagreement was that metastases were present more frequently and/or in larger number on 18F-FDG PET/CT than MDCT in the contralateral mediastinal, supraclavicular, and distant lymph nodes, as well as in the bones and suprarenal glands. Since 18F-FDG PET/CT detected more regional and distant metastases than MDCT, we conclude that FDG PET/CT is useful for staging/restaging and planning treatment of patients with NSCLC. KEYWORDS: Non-small cell lung cancer, positron emission tomography, multidetector computed tomography, metastases detection.
RESUMO
Acetylcholine interacts with endothelial muscarinic receptors releasing nitric oxide and causing vasodilatation. To identify the receptor subtype responsible for acetylcholine-induced relaxation in canine uterine artery, the usual organ bath method for in vitro investigation on isolated blood vessels was applied. Using a range of muscarinic receptor antagonists such as atropine (nonselective), pirenzepine (M(1)-selective), methoctramine (M(2)-selective) and p-fluoro-hexahydro-sila-difenidol (p-FHHSiD) (M(1)/M(3)) and determining pA2 value of those antagonists through Shild analysis, we aimed at establishing a precise receptor mechanism underlying acetylcholine-induced relaxation in isolated canine uterine artery. The relaxation of uterine arterial rings in response to acetylcholine in the presence or absence of selective muscarinic receptors antagonists was calculated using concentration response curves. Acetylcholine induced concentration-dependent and endothelium-dependent relaxation of arterial rings precontracted with phenylephrine (pEC(50) = 6.90 +/- 0.02). Muscarinic receptors antagonists atropine, pirenzepine, methoctramine and p-FHHSiD competitively antagonized the response to acetylcholine and obtained pA(2) values were 9.91 +/- 0.06, 6.60 +/- 0.04, 6.21 +/- 0.08 and 8.05 +/- 0.1, respectively. This study showed that acetylcholine induced endothelium-dependent relaxation of canine uterine artery by stimulation of muscarinic receptors localized on the endothelial cells. On the basis of differential antagonist affinity, we suggest that the muscarinic receptors involved in the acetylcholine-induced relaxation of canine uterine artery are predominantly of M(3) subtype.
