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21.
Alberts GL Pregenzer JF Im WB Zaworski PG Gill GS 《European journal of pharmacology》1999,383(3):311-319
The 5-HT(2C) receptor as heterologously expressed in various mammalian cells mediates inositol 1,4,5-triphosphate (IP(3)) signal by activating G(q/11) subtypes of G proteins, but minimally promotes agonist-induced GTPgamma35S binding in membranes due to slow GTP turnover rates of the G proteins. Here we discovered robust (over 200%) agonist-induced GTPgamma35S binding mediated by the human receptor expressed in human embryonic kidney (HEK) 293 cells, and investigated its pharmacology. Agonists concentration-dependently increased GTPgamma35S binding in isolated membranes, which was competitively blocked by antagonists. Intrinsic efficacies of agonists from GTPgamma35S binding were comparable to those from IP(3) measurement. Pertussis toxin treatment largely blocked serotonin-induced GTPgamma35S binding, serotonin high affinity sites by 70% without altering the total binding sites, and reduced IP(3) release by 40%. GTPgamma35S-bound Galpha subunits from serotonin-activated membranes were mainly Galpha(i), judging from immobilization studies with various Galpha-specific antibodies. Inhibition of forskolin-stimulated cAMP formation, however, was not observed. Apparently, the 5-HT(2C) receptor-mediated GTPgamma35S binding is a unique phenotype observed in HEK293 cells, reflecting its coupling to pertussis toxin-sensitive G(i) subtypes, which contribute to the IP(3) signal, along with pertussis toxin-insensitive G(q/11) subtypes. 相似文献
22.
To elucidate the nature of the apical opacity that is commonly seen in patients with tuberculosis--usually referred to as an "apical cap" or "apical pleural thickening"--18 patients with upper lobe tuberculosis were studied with high-resolution computed tomography (HRCT). All had a homogeneous apical opacity at least 1 cm thick on chest radiographs. Fifteen of the 18 had a history of pulmonary tuberculosis of more than 5 years duration, and nine showed evidence of ipsilateral pleurisy. HRCT scans at the apex of the thorax in all nine patients scanned at this level showed that extrapleural fat with interspersed vessels accounted for most of the plain radiographic opacity. Scans obtained at a level slightly above visible aerated lung showed extrapleural fat 3-25 mm thick peripherally and atelectatic lung centrally. At more caudal levels, at which both aerated lung and "thickened pleura" were visible on plain radiographs, HRCT showed extrapleural fat (3-20 mm thick), thickened pleura (1-3 mm thick), and atelectatic lung peripherally and areas of emphysematous bullae, bronchiectasis, and atelectatic lung centrally. 相似文献
23.
24.
Moon WK Chang KH Weinmann HJ Koh YH Im JG Yeon KM Han MC 《AJR. American journal of roentgenology》2000,174(5):1385-1390
OBJECTIVE: The objective of this study was to compare enhancement patterns of a blood-pool contrast agent, Gadomer-17, with those of gadopentetate dimeglumine in bacterial abscesses and VX2 carcinoma in rabbits. MATERIALS AND METHODS: Fourteen rabbits with experimentally induced bacterial abscesses and VX2 carcinoma in both thighs underwent dynamic contrast-enhanced MR imaging with Gadomer-17 and gadopentetate dimeglumine at a 24-hr interval. The enhancement ratios (postcontrast to precontrast signal intensities) of lesions in the same animal were assessed and correlated with microvessel density. RESULTS: For Gadomer-17, the enhancement ratio of the abscesses (1.66 +/- 0.39) peaked 15 min after the injection, while that of the carcinoma (2.05 +/- 0.16) peaked at 10 min. The enhancement ratios of the carcinoma were consistently higher than those of the abscesses up to 30 min. For gadopentetate dimeglumine, peak enhancement ratio of the abscesses (2.30 +/- 0.75) was seen 5 min after the injection, while that of the carcinoma (2.32 +/- 0.51) was seen at 3 min. The enhancement ratios of the carcinomas were significantly higher at 1 min, but significantly lower at 20-30 min, compared with those of the abscesses, as a result of rapid decrease of enhancement ratios in the carcinomas. The microvessel density was 9.8 +/- 5.2 vessels per field of view for the abscesses and 36.3 +/- 9.5 vessels per field of view for the carcinoma (p < 0.001). CONCLUSION: Delayed peak enhancement and slow decay were found in both bacterial abscess and VX2 carcinoma with Gadomer-17, whereas early peak enhancement and rapid decay were found especially in VX2 carcinoma with gadopentetate dimeglumine. Enhancement ratios on MR imaging with a blood-pool contrast agent correlated well with the microvessel density in bacterial abscess and VX2 carcinoma. 相似文献
25.
Boo-Kyung Han Jung-Gi Im Hak Soo Kim Jin Mo Koo Hong Dae Kim Kyung Mo Yeon 《Korean journal of radiology》2000,1(3):127-134
Objective
To determine the extent to which thin-section and volumetric three-dimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity.Materials and Methods
In eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were measured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways.Results
Cross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pressure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size.Conclusion
Thin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size. 相似文献26.
Qihang Chen Jin Mo Goo Joon Beom Seo Myung Jin Chung Yu-Jin Lee Jung-Gi Im 《Korean journal of radiology》2000,1(3):135-141
Objective
To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases.Materials and Methods
Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radiography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall information.Results
SSD images were the most informative with regard to the detection (3.95±0.31), localization (3.95±0.22) and extent of a lesion (3.85±0.42), and overall information (3.83±0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56±0.50) and characterization of the lesion (3.51±0.61).Conclusion
SSD images and thin-section spiral CT scans can provide valuable information for the evaluation of tracheobronchial disease. 相似文献27.
Digital chest radiography with a selenium-based flat-panel detector versus a storage phosphor system: comparison of soft-copy images 总被引:5,自引:0,他引:5
Goo JM Im JG Kim JH Seo JB Kim TS Shine SJ Lee W 《AJR. American journal of roentgenology》2000,175(4):1013-1018
OBJECTIVE. We compared the soft-copy images produced by a digital chest radiography system that uses a flat-panel X-ray detector based on amorphous selenium with images produced by a storage phosphor radiography system for the visualization of anatomic regions of the chest. MATERIALS AND METHODS. Two chest radiologists and two residents analyzed 46 pairs of posteroanterior chest radiographs on high-resolution video monitors (2560 x 2048 x 8 bits). In each pair, one radiograph was obtained with a storage phosphor radiography system, and the other radiograph was obtained with a selenium-based flat-panel detector radiography system. Each pair of radiographs was obtained at the same exposure settings. The interpreter rated the visibility and radiographic quality of 11 different anatomic regions. Each pair of images was ranked on a five-point scale (1 = prefer image A, 3 = no preference, 5 = prefer image B) for preference of technique. Statistical significance of preference was determined using the Wilcoxon's signed rank test. RESULTS. The interpreters had a statistically significant preference for the selenium-based radiography system in six (unobscured lung, hilum, rib, minor fissure, heart border, and overall appearance) of 11 anatomic regions (p<0.001) and for the storage phosphor system in two regions (proximal airway and thoracic spine) (p<0.05). Chest radiologists strongly preferred selenium-based images in eight regions, and they did not prefer storage phosphor images in any region. CONCLUSION. The soft-copy images produced by the selenium-based radiography system were perceived as equal or superior to those produced by the storage phosphor system in most but not all anatomic regions. 相似文献
28.
Renal and pulmonary lymphangioleiomyomatosis: a case report 总被引:1,自引:0,他引:1
Lymphangioleiomyomatosis (LAM) is a rare disease that most commonly involves the lung. However, extrapulmonary lymphangioleiomyomatosis rarely occurs with or without subsequent involvement of the lung. We report a case of incidentally found renal and pulmonary lymphangioleiomyomatosis in a patient who had no stigmata of tuberous sclerosis. 相似文献
29.
30.
Chang-Hee Kim Jung Eun Shin Young Soo Yang Donghyuk Im 《International journal of audiology》2016,55(10):541-546
Objectives: To investigate the initial findings of positional nystagmus in patients with sudden sensorineural hearing loss (SSNHL) and positional vertigo, and to compare hearing improvement among patients with different types of positional nystagmus. Design: The characteristics of positional nystagmus upon initial examination were analysed, and the initial mean pure-tone audiometry (PTA) threshold was compared with that at three months after treatment. Study sample: Forty-four SSNHL patients with concomitant positional vertigo were included. Results: Positional nystagmus was classified into five subgroups; persistent geotropic direction-changing positional nystagmus (DCPN) in head-roll test (HRT) and negative Dix-Hallpike test (DHT), persistent apogeotropic DCPN in HRT and negative DHT, positive DHT and negative HRT, persistent geotropic DCPN in HRT and positive DHT, and persistent apogeotropic DCPN in HRT and positive DHT. PTA threshold improvement was significantly greater in SSNHL patients with negative DHT than with positive DHT (p?=?0.027). Conclusions: When geotropic DCPN was elicited by HRT, the nystagmus was persistent, which suggests that alteration of specific gravity of the endolymph, rather than the lateral canal canalolithiasis, may be a cause of this characteristic positional nystagmus. Positive DTH may be a prognostic factor for worse hearing recovery among patients with SSNHL and positional vertigo. 相似文献