Self-expandable metal stents for malignant esophageal obstruction: a comparative study between extrinsic and intrinsic compression.

Self-expandable metal stents (SEMSs) are effective for malignant esophageal obstruction, but usefulness of SEMSs in extrinsic lesions is yet to be elucidated. This study is aimed at evaluating the clinical usefulness of SEMSs in the extrinsic compression compared with intrinsic. A retrospective review was conducted for 105 patients (intrinsic, 85; extrinsic, 20) with malignant esophageal obstruction who underwent endoscopic SEMSs placement. Technical and clinical success rates were evaluated and clinical outcomes were compared between extrinsic and intrinsic group. Extrinsic group was mostly pulmonary origin. Overall technical and clinical success rate was 100% and 91%, respectively, without immediate complications. Extrinsic and intrinsic group did not differ significantly in clinical success rate. The median stent patency time was 131.3 ± 85.8 days in intrinsic group while that of extrinsic was 54.6 ± 45.1 due to shorter survival after stent insertion. The 4-, 8-, and 12-week patency rates were 90.5%, 78.8%, and 64.9% respectively in intrinsic group, while stents of extrinsic group remained patent until death. Uncovered, fully covered, and double-layered stent were used evenly and the types did not influence patency in both groups. In conclusion, esophageal SEMSs can safely and effectively be used for malignant extrinsic compression as well as intrinsic.

The effects of 5-hydroxytryptamine1a receptor agonist, buspirone on the gastric fundus accommodation in an animal model using guinea pigs.

BACKGROUND: To date, few animal experiments have been conducted to examine the effects and mechanisms of buspirone in inducing the relaxation of the gastric fundus. The aim of this study is to examine the effects and mechanisms of buspirone, 5-HT(1a) receptor agonist, in the accommodation of gastric fundus muscle in an animal experimental model using guinea pigs. METHODS: In the current study, we performed an immunohistochemistry for 5-HT(1a) receptors in the tissue samples collected from the stomach of guinea pig, an ex vivo experiment to examine the electrical field stimulation (EFS)-induced relaxation of the circular muscle in the gastric fundus in guinea pigs and an in vivo experiment to measure the intragastric pressure through the insertion of the balloon catheter in the fundus. KEY RESULTS: Immunohistochemical stains for 5-HT(1a) receptor could confirm the expression of 5-HT(1a) receptor in guinea pig stomach. There was a significant dose-dependent inhibition of the EFS-induced relaxation of fundic muscle strips following the treatment with WAY-100635 (5-HT(1a) antagonist), but this was significantly improved following the treatment with buspirone. An in vivo measurement of the gastric fundic tone showed that there was a significant decrease in the intragastric pressure at same volume by pretreatment with buspirone as compared with the vehicle control, but this could be prevented with the treatment with WAY-100635. CONCLUSIONS & INFERENCES: Based on our results, it can be concluded that buspirone is effective in relaxing the gastric fundus via 5-HT(1a) receptor pathway in both in vitro and in vivo experimental models using guinea pigs.

Treatment outcomes of 70 cases of early esophageal carcinoma: 12 years of experience.

Early esophageal cancer (EEC) has an excellent prognosis compared to advanced esophageal cancer. Nowadays, endoscopic mucosal resection (EMR) may offer another alternative to cure early cancers of the gastrointestinal tract. We aimed to evaluate the clinical outcomes of EEC in Korea after curative treatments; EMR or surgery. We retrospectively reviewed the medical records of patients diagnosed as EEC from January 1994 to August 2005 at Yonsei University Medical Center, Seoul, Korea. Among 888 patients diagnosed with esophageal cancer, 70 (7.9%) were included as EEC. Among them, 10 patients (14.3%) were treated by EMR, and 50 (71.4%) by operation. The treatment outcomes of EEC in relation to various clinicopathologic factors along with survival rates were analyzed. There were 18 cases (30%) of mucosal lesions and 42 cases (70%) of submucosal lesions. Overall 5-year survival rate was 84.3%. When comparing treatment outcomes between EMR-treated and operated groups, there were no significant differences in complete remission (80%vs. 84%), recurrence (20%vs. 16%) and 5-year survival rate (100%vs. 78.3%). EEC is a potentially curable entity with a good clinical prognosis. EMR can be considered as another treatment arm for EEC, along with surgical resection.

Factors affecting long-term clinical outcomes of endoscopic mucosal resection of early gastric cancer.

BACKGROUND/AIMS: Endoscopic mucosal resection (EMR) has been widely accepted as a treatment option for early gastric cancer (EGC) in selected cases. The purposes of this study were to evaluate the long-term outcomes and the factors affecting the clinical outcomes, of EMR performed in EGC. METHODOLOGY: Between April 1996 and March 2005, 147 patients have undergone EMR to treat EGC at Yonsei University Medical Center, Seoul, Korea. We assessed the clinical outcomes of the EMR for EGC in a long-term follow-up period. We also reviewed the medical records of the patients including demographic data, endoscopic characteristics of the lesion and histopathologic findings. RESULTS: The histopathologic evaluations after the EMR treatment showed that overall complete resection rate was 84.6% (126/149) while complete resec tion rate of 93.5% was achieved in mucosal cancers (115/123). The success of complete resection was significantly affected by endoscopic gross type (depressed lesion), the degree of differentiation, and the depth of invasion, independently. There were only 5 cases of local recurrence during the follow-up periods, and the recurred or incompletely resected lesions were successfully treated by salvage operation or endoscopic retreatment. There was no disease-related or treatment-related mortality during the follow-up period. CONCLUSIONS: EMR is a good and safe curative treatment option with feasible clinical outcomes in patients with EGC. It must be emphasized that a proper selection of candidates is mandatory to improve the clinical outcome of EMR in EGC.

The metallic composition of aerosols at three monitoring sites in Korea during winter 2002.

In the present study, the distribution patterns of various metals were analyzed and compared using PM samples collected concurrently from three monitoring sites located in Korea (Seoul, Busan, and Jeju island) in December 2002. As these sites can represent metal pollution with different degrees of anthropogenic activities, their concentration levels were distinguished in a systematic manner in the order of Jeju, Busan, and Seoul. By comparing the present data sets with those measured previously from other locations in Korea and around the world, we attempted to diagnose the general status of elemental pollution on the Korean peninsula. Through an application of different statistical approaches, the major processes controlling elemental levels were assessed for each of the three study sites. The results indicated the importance of both crustal and anthropogenic sources in all sites with their relative roles varying significantly from each other. The results of the metal analysis data, when examined in relation to back trajectory analysis, confirmed that their concentration changes are affected quite sensitively with air mass movement patterns. The overall results of this study consistently indicated the contribution of a strong anthropogenic source area (e.g., China) to the observed metal concentration levels in the study area, but the strengths of such signals vary considerably across the Korean peninsula.

The effects of wind speed on the relative relationships between different sized-fractions of airborne particles.

The concentrations of three different size fractions of particulate matter (PM) including PM2.5, PM10, and TSP were determined continuously at hourly intervals from four different sites in Seoul, Korea during the spring of 2001. To learn the effects of wind speed change on PM fractionation, the entire data sets were initially sorted into three particle fractions such as: fine (F: PM2.5), coarse (C: PM10-PM2.5), and giant (G: TSP-PM10). The inter-fraction relationships of PM were then explored by linear regression analysis of the data divided into four wind speed regimes. The results of this analysis, when examined in terms of either relative dominance between different PM fractions (i.e., in terms of their slope values) or strength of correlations, indicate the existence of diverse inter-fraction patterns. Most importantly, the physical influence of wind speed is seen to be reflected most efficiently between fine and coarse particle fractions, as the relative contribution of coarse fraction to the mass concentration of total particles (e.g., PM10) changes proportionally with changes in wind speed. However, such systematic patterns decrease noticeably between fine and giant fractions, as they can be affected more sensitively by such factors as the nature of their sources or the surrounding environmental conditions. The results of our comparative analysis thus confirm that wind speed is a useful barometer to distinguish and predict the behavior of different particle fractions in relation to each other.

Neural crest stem cell and cardiac endothelium defects in the TrkC null mouse.

TrkC null mice have multiple cardiac malformations. Since neural crest cells participate in cardiac outflow tract septation, the aim of this study was to determine at the cellular level the putative neural crest defect. We have identified three types of progenitor cells: stem cells that undergo self-renewal and can generate many cell types, cells that are restricted in their developmental potentials, and cells that are committed to the smooth muscle cell lineage. In TrkC null mice, there is a greater than 50% decrease in stem cell numbers and an equivalent increase in fate-restricted cells. The outflow tract wall is thickened and the endothelial tube is disorganized. We conclude that deletion of the TrkC gene causes precocious fate restrictions of the neural crest stem cell and a defect of the outflow tract endothelium, both of which may contribute to the outflow tract malformations that occur in TrkC null mice.

Ubiquitous embryonic expression of the norepinephrine transporter.

We report that the norepinephrine transporter (NET) is expressed in avian and mouse embryos by numerous tissues that are derived from all three germ layers. In the nervous system, NET is expressed in the neuroepithelium of the brain and the spinal cord (ventral horn and floor plate), forming mesencephalic nuclei, neural crest, dorsal root ganglion, sympathetic ganglion and spinal nerve. Nonneuronal embryonic NET-expressing structures include the olfactory epithelium, the notochord, the somitic dermamyotome and mesenchymal cells in the limb bud. NET is expressed prominently in the cardiovascular system, including endothelial cells of forming blood vessels, the walls of the aorta and veins, the epicardium, myocardium and a subset of blood cells. The gut, lung buds, and in particular the kidneys, are intensely NET immunoreactive. Since neurotransmitters are known to affect proliferation, survival and differentiation of many mesenchymal cell types, NET function may be a physiologically relevant regulatory element in embryonic development. A working model is proposed for neurotransmitter transporter function in the embryo as a system for the concentration and targeted delivery of neurotransmitter.

Surface measurements of global warming causing atmospheric constituents in Korea.

The expansion of the industrial economy and the increase of population in Northeast Asian countries have caused much interest in climate monitoring related to global warming. However, new techniques and better platforms for the measurement of global warming and regional databases are still old-fashioned and are not being developed sufficiently. With respect to this agenda, since 1993, at the request of the World Meteorological Organization (WMO), to monitor functions of global warming, the Korea Meteorological Administration (KMA) has set up a Global Atmospheric Watch (GAW) Station on the western coast of Korea (Anmyun-do) and has been actively monitoring global warming over Northeast Asia. In addition, atmospheric carbon dioxide (CO2) has been measured for a similar KMA global warming program at Kosan, Cheju Island since 1990. Aerosol and radiation have also been measured at both sites as well as in Seoul. The observations have been analyzed using diagnostics of climate change in Northeast Asia and also have been internationally compared. Results indicate that greenhouse gases are in good statistic agreement with the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) long-term trends of monthly mean concentrations and seasonal cycles. Atmospheric particulate matter has also been analyzed for particular Asian types in terms of optical depth, number concentration and size distribution.