Liver transplantation in Korea: past, present, and future

PURPOSE

This study reviewed the past and present status of liver transplantation (LT) and outlooks for the future of LT in Korea.

METHOD

The first LT in Korea was successfully performed using a deceased donor graft in 1988. Pediatric and adult living donor liver transplantations (LDLTs) were initiated in 1994 and 1997, respectively. From 1988 to 2013, 10,581 LTs were performed at 40 centers, whereas LDLT accounted for 76.5% of all LTs.

RESULTS

In the early 1990s, the deceased organ donation rate was less than 1.5 per million population (PMP) per year, but it increased to 5 PMP beginning in 2008. Despite the increasing number of deceased donor liver transplantations (DDLTs), high prevalence of hepatitis B virus (HBV)-induced cirrhosis and hepatocellular carcinoma (HCC) has provoked persistent performance of adult LDLT with technical advancement including middle hepatic vein (MHV) reconstruction of right lobe graft and dual graft LDLT with 1 nationwide donor mortality.

CONCLUSION

The number of LTs in Korea in 2010 was 23.2 PMP (1042 LTs/45 million population), lower than 23.5 PMP of Spain, but higher than 20 PMP of the United States. However, future LT numbers may decrease because of lowering the HBV carrier rate (neonatal HBV universal vaccination began in 1992), new potent anti-HBV agents, and lowest birth rate (1.22 children per family) with a decrease of potential live donors.

Expression pattern analysis of hepatocellular carcinoma tumor markers in viral hepatitis B and C patients undergoing liver transplantation and resection

BACKGROUND

This study was conducted to compare the expression patterns of serum alpha-fetoprotein (AFP) and proteins induced by vitamin K absence or antagonist-II (PIVKA-II) in hepatocellular carcinoma (HCC) patients undergoing liver transplantation (LT) and resection at a high-volume single institution.

METHODS

First, 663 liver transplant recipients with HCC were selected. They were divided into hepatitis B virus (HBV) (n = 628) and hepatitis C virus (HCV) groups (n = 35). Their medical records were retrospectively reviewed. Second, another cohort of 2709 patients who underwent HCC resection included 2258 HBV, 143 HCV, and 308 non-HBV non-HCV (NBNC) patients.

RESULTS

In the transplantation group, pretransplantation AFP level >20 ng/mL was observed in 42.5% of HBV patients and 60% of HCV patients (P = .042). PIVKA-II level >40 mAU/mL was observed in 30.6% of HBV patients and 42.9% of HCV patients (P = .127). In the resection group, a preoperative AFP level >20 ng/mL was observed in 51.7% of HBV patients and 43.3% of HCV patients (P = .052). PIVKA-II level >40 mAU/mL was observed in 59.7% of HBV patients and 56.6% of HCV patients (P = .47). Preoperative AFP level >20 ng/mL and PIVKA-II level >40 mAU/mL were observed in 35.7% and 61% of NBNC patients, respectively. Receiver-operator characteristic curve analyses revealed that the expression pattern of PIVKA-II in patients with elevated AFP level was not predictable and vice versa, regardless of background liver diseases.

CONCLUSIONS

This study indicates that serum AFP and PIVKA-II may be expressed variably regardless of the types of background liver disease. Further large-volume multicenter studies are needed to evaluate the possibility of the etiology-dependent expression of tumor markers.

Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR

A second electron cyclotron emission imaging (ECEI) system has been installed on the KSTAR tokamak, toroidally separated by 1/16th of the torus from the first ECEI system. For the first time, the dynamical evolutions of MHD instabilities from the plasma core to the edge have been visualized in quasi-3D for a wide range of the KSTAR operation (B0 = 1.7∼3.5 T). This flexible diagnostic capability has been realized by substantial improvements in large-aperture quasi-optical microwave components including the development of broad-band polarization rotators for imaging of the fundamental ordinary ECE as well as the usual 2nd harmonic extraordinary ECE.

Upgrades of imaging x-ray crystal spectrometers for high-resolution and high-temperature plasma diagnostics on EAST

Upgrade of the imaging X-ray crystal spectrometers continues in order to fulfill the high-performance diagnostics requirements on EAST. For the tangential spectrometer, a new large pixelated two-dimensional detector was deployed on tokamaks for time-resolved X-ray imaging. This vacuum-compatible detector has an area of 83.8 × 325.3 mm(2), a framing rate over 150 Hz, and water-cooling capability for long-pulse discharges. To effectively extend the temperature limit, a double-crystal assembly was designed to replace the previous single crystals for He-like argon line measurement. The tangential spectrometer employed two crystal slices attached to a common substrate and part of He- and H-like Ar spectra could be recorded on the same detector when crystals were chosen to have similar Bragg angles. This setup cannot only extend the measurable Te up to 10 keV in the core region, but also extend the spatial coverage since He-like argon ions will be present in the outer plasma region. Similarly, crystal slices for He-like iron and argon spectra were adopted on the poloidal spectrometer. Wavelength calibration for absolute rotation velocity measurement will be studied using cadmium characteristic L-shell X-ray lines excited by plasma radiation. A Cd foil is placed before the crystal and can be inserted and retracted for in situ wavelength calibration. The Geant4 code was used to estimate X-ray fluorescence yield and optimize the thickness of the foil.

Wavelength calibration of x-ray imaging crystal spectrometer on Joint Texas Experimental Tokamak

The wavelength calibration of x-ray imaging crystal spectrometer is a key issue for the measurements of plasma rotation. For the lack of available standard radiation source near 3.95 Å and there is no other diagnostics to measure the core rotation for inter-calibration, an indirect method by using tokamak plasma itself has been applied on joint Texas experimental tokamak. It is found that the core toroidal rotation velocity is not zero during locked mode phase. This is consistent with the observation of small oscillations on soft x-ray signals and electron cyclotron emission during locked-mode phase.

Performance of select color-difference formulas in the blue region

The main objective of this work was to test the performance of major formulas for assessment of small suprathreshold color differences in the blue region. The models examined include CIELAB color space based equations, including CIELAB, CIE94, CIEDE2000, CMC (l:c), BFD (l:c), and formulas based on more uniform color spaces, such as DIN99d, CAM02-SCD, CAM02-UCS, OSA-GP, and OSA-Eu in comparison against data obtained via visual assessments. For this purpose, a dataset around the CIE high-chroma blue color center, hereafter called NCSU-B2, was developed. The NCSU-B2 dataset comprised 65 textile substrates and a standard, with a mean ΔE(ab)* color difference of 2.72, ranging from 0.54-5.72. Samples were visually assessed by 26 subjects against the reference gray scale in three separate trials with at least 24 h between assessments. A total of 5070 assessments were obtained. The standardized residual sum of squares (STRESS) index was used to examine the performance of various formulas for this dataset, as well as a previously developed NCSU-B1 low-chroma blue dataset [Color Res. Appl. 36, 27, 2011], and blue centers from other established visual datasets. Results show that formulas based on more recent uniform color spaces provide better agreement with perceptual data compared with models based on CIELAB space.

Toroidal mode number estimation of the edge-localized modes using the KSTAR 3-D electron cyclotron emission imaging system

A new and more accurate technique is presented for determining the toroidal mode number n of edge-localized modes (ELMs) using two independent electron cyclotron emission imaging (ECEI) systems in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The technique involves the measurement of the poloidal spacing between adjacent ELM filaments, and of the pitch angle α* of filaments at the plasma outboard midplane. Equilibrium reconstruction verifies that α* is nearly constant and thus well-defined at the midplane edge. Estimates of n obtained using two ECEI systems agree well with n measured by the conventional technique employing an array of Mirnov coils.

A pilot study on the safety and efficacy of generic mycophenolate agent as conversion maintenance therapy in stable liver transplant recipients

PURPOSE

The patent covering mycophenolate mofetil (MMF) in Korea has expired and, thus, several generic MMF agents are now commercially available. The supply of Cellcept (Roche Korea) was interrupted at the end of 2011, so it was inevitable that a generic MMF would be used instead. During this period, we performed a prospective pilot study to examine the safety and efficacy of a generic mycophenolate agent (Myconol: Hanmi Pharmaceutical, Seoul Korea) for use as conversion maintenance therapy in stable liver transplantation (OLT) recipients.

METHODS

OLT recipients, who were treated with MMF on an outpatient basis from January 2012 to March 2012, attended follow-up interviews conducted. The patients had undergone OLT ≥ 2 years before the study, had tolerated Cellcept, and showed stable liver function. Fifty-three patients were followed up for more than 3 months after conversion to the same dose of Myconol.

RESULTS

After conversion to Myconol, 6 patients (11.3%) experienced new side effects, which disappeared when they reverted to Cellcept (n = 5) or stopped taking Myconol medication (n = 1). The side effects associated with Myconol included gastrointestinal symptoms (indigestion and diarrhea; n = 3), skin eruptions (n = 1), pruritus (n = 1), and insomnia (n = 1). The mean mycophenolic acid levels were 1.71 ± 0.88 μg/mL for Cellcept and 1.83 ± 0.91 μg/mL for Myconol, which showed a strong correlation (r(2) = 0.92, P < .001).

CONCLUSIONS

Myconol showed similar pharmacokinetics to those of Celcept, but a small proportion of patients experienced agent-specific side effects; therefore, patients should be closely monitored when taking Myconol. Also, further studies, with a greater number of patients, are required to identify the full spectrum of drug-associated side effects.

First Report of Powdery Mildew Caused by Erysiphe alphitoides on Japanese Snailseed (Cocculus trilobus) in Korea

Japanese snailseed (Cocculus trilobus DC.) has been known as a medicinal herb to treat dieresis, rheumatoid arthritis, and dropsy. In September 2011, severe powdery signs were found on several Japanese snailseed plants near Andong, Korea. Diseased leaves showed chlorotic or necrotic lesions, along with leaf distortion and senescence. Diseased leaves were associated with a fungus that resulted in what appeared to be white colonies, predominately associated with the upper leaf surfaces, and rarely on the lower surfaces. The colonies increased in size and coalesced, subsequently covering the entire surface. The fungus-produced chasmothecia were 92 to 123 μm in diameter, blackish brown, and had a depressed, globose shape. Each chasmothecium had approximately 8 to 12 appendages that were straight to mildly bent, and were four to six times dichotomously branched and often entwined. There were three to six asci per chasmothecium, 38 to 57 × 32 to 43 μm in size, each of which held six to eight ascospores. Conidiophores were single or sometimes two on a hyphal cell, arising from the upper part of mother cells, mostly positioned central, 6.5 to 8 μm with width. Conidiophores were erect and up to 150.5 μm long. Conidia were ellipsoidal or sometimes lemon-shaped. The conidial size was 31.5 to 40 × 19 to 24.5 μm with length/width. These morphological characteristics were identified as being similar to Erysiphe alphitoides (1). DNA was extracted from collected hyphae of infected leaves using the NucleoSpin Tissue Kit (Macherey-Nagel, Duren, Germany). The ITS region of rDNA was amplified using primers ITS4/ITS5 and sequenced (GenBank Accession No. KF734882). The isolate (APEC-F1203) was 99% homologous to other E. alphitoides isolates from oak trees in Japan (AB292704, AB292699, AB292697, and AB292701) and Europe (EF672350, AJ417497). In Korea, this fungus is an oak tree pathogen (2). As proof of pathogenicity, infected leaves having abundant sporulation were pressed onto leaves of five healthy plants. Inoculated and non-inoculated plants were incubated in a moist chamber for 48 h and then maintained in a greenhouse at 15 to 22°C. After 10 to 12 days, powdery mildew colonies developed on inoculated plants. Uninoculated control plants did not show powdery mildew. Microscopic observation of the pathogen growing on the inoculated plants revealed that it was the same as the original fungus. We also observed powdery mildews on oak tree leaves around Japanese snailseed and analyzed their ITS sequences with the above-mentioned methods. As a result, the ITS sequences of powdery mildew pathogens obtained from Japanese snailseed and oak tree were identical. To our knowledge, this is the first report of the presence of E. alphitoides on Japanese snailseed in Korea. This fungus has been reported in association with numerous oak (Quercus spp.) species in Korea, showing that it may be a potential source of inoculum in Japanese snailseed. References: (1) S. Takamatsu et al. British Mycol. Res. 111:809. 2007. (2) S. H. Yu. List of Plant Diseases in Korea, 5th ed. The Korean Society of Plant Pathology, 2009.

Upgraded high time-resolved x-ray imaging crystal spectroscopy system for J-TEXT ohmic plasmas

This paper presents the upgraded x-ray imaging crystal spectrometer (XICS) system on Joint Texas Experimental Tokamak (J-TEXT) tokamak and the latest experimental results obtained in last campaign. With 500 Hz frame rate of the new Pilatus detector and 5 cm × 10 cm spherically bent crystal, the XICS system can provide core electron temperature (Te), core ion temperature (Ti), and plasma toroidal rotation (VΦ) with a maximum temporal resolution of 2 ms for J-TEXT pure ohmic plasmas. These parameters with high temporal resolution are very useful in tokamak plasma research, especially for rapidly changed physical processes. The experimental results from the upgraded XICS system are presented.

Toward more than 400 liver transplantations a year at a single center

BACKGROUND

For the first time at Asan Medical Center (AMC) we performed more than 400 liver transplantations (LTs) per year in 2011, despite same number of living donor liver transplantations (LDLTs).

METHODS

Our OLT program was started in 1992, but not activated well due to the scarcity of deceased donor organs. Since adult LDLTs using a left lobe and then a right lobe were successfully performed in 1997, we have developed several innovative techniques and approaches for adult LDLT, for example, modified right-lobe graft reconstructing middle hepatic branches in 1998, dual graft LDLT using 2 left lobes in 2000; new criteria for hepatocellular carcinoma (HCC); as well as ABO-incompatible LDLT, the first in the world. As a result, the number of LDLTs has increased rapidly but reached a plateau recently. Nationwide efforts to promote deceased donation increased the number of deceased donor liver transplantation (DDLT).

RESULTS

We have performed 317 LDLTs per year in 2010 and 2011, respectively. The number of LTs reached 403 in 2011. This large number was possible due to a remarkable increase of DDLTs from 50 in 2010 to 86 in 2011. Seventy-nine patients (68.1%) among 116 patients (28.8%) required an urgent LT receiving a DDLT. LT for HCC or ABO-mismatch comprised 50.3% (n = 150) or 8.7% (n = 35), respectively. In-hospital mortality rate in 2011 was 4.7%.

CONCLUSIONS

The increased LTs number at AMC was aided by the nationwide campaign.

Rotational resonance of nonaxisymmetric magnetic braking in the KSTAR tokamak

One of the important rotational resonances in nonaxisymmetric neoclassical transport has been experimentally validated in the KSTAR tokamak by applying highly nonresonant n=1 magnetic perturbations to rapidly rotating plasmas. These so-called bounce-harmonic resonances are expected to occur in the presence of magnetic braking perturbations when the toroidal rotation is fast enough to resonate with periodic parallel motions of trapped particles. The predicted and observed resonant peak along with the toroidal rotation implies that the toroidal rotation in tokamaks can be controlled naturally in favorable conditions to stability, using nonaxisymmetric magnetic perturbations.

Apparent treatment-resistant hypertension among elderly Korean hypertensives: an insight from the HIT registry

The aim of this study was to determine the clinical characteristics of patients with resistant hypertension (RH) and predictors among elderly Korean hypertensives. This prospective, multi-center, observational study evaluated 2439 elderly hypertensive patients between December 2008 and November 2011, who visited secondary hypertension clinics for high blood pressure (BP). Patients were categorized as resistant if their BP was ≥140/90 mm Hg and if they reported using antihypertensive medications from three different drug classes, including a diuretic or drugs from ≥4 antihypertensive drug classes, regardless of BP. Characteristics of patients with RH were compared with those of patients who were controlled with one or two antihypertensive medications after 6-month antihypertensive treatment. In comparison with 837 patients with non-RH, 404 patients with RH were more likely to be aware of their status of high BP before enrollment and have a high baseline systolic BP ≥160 mm Hg, microalbuminuria, high body mass index (BMI) ≥24 kg m(-2) and diabetes mellitus (DM). In drug-naive patients, awareness of hypertension at baseline was the only independent predictor for RH. In elderly Korean hypertensives, BMI (≥24 kg m(-2)), baseline systolic BP (≥160 mm Hg), microalbuminuria, DM and awareness of hypertension showed an association with RH.

First Report of Cane and Leaf Rust on Rubus fruticosus Caused by Kuehneola uredinis in Korea

In September 2011, we observed a rust disease affecting about 90% of the leaves of several Rubus fruticosus L. plants at Andong (36°32'12.4″ N, 128°47'20.1″ E), Korea. Pustule formation occurred on cane surfaces and on the undersurfaces of leaves, with yellowing, reddening, and necrosis on the corresponding upper leaf surface. Leaf distortion and senescence also occurred. For light and scanning electron microscopy, uredinia were detached from leaf lesions using a razor blade and then mounted in water without staining. Leaves with lesions were prepared by gold sputtering and then observed by SEM (Hitachi S-2500C microscope, Japan). We observed the development of uredinial colonies with abundant sporulation. The echinulate urediniospores, which were 16.3 to 19.8 × 17.5 to 25.3 μm, were yellowish or occasionally pale brown, with a globose or subglobose shape (2). Telia were a floccose and pale yellowish-buff or almost white. Teliospores were four- to seven-celled. Cells were trapezoid-cylindric, 15 to 40 × 14 to 24 μm, with hyaline walls. Cell wall surface was smooth but often bearing coronate projections or bumps at the top (in apical cells) or upper rim (in intercalary cells). Cell wall thickness was about 0.5 μm at the sides and 2 to 4 μm at the apex; apical pores occurred on short cell-wall projections. Teliospore pedicels were short (0.17 to 1.34 × 0.78 to 1.45 μm), hyaline, and fragile (3). The pathogen was identified as Kuehneola uredinis L. on the basis of morphology (3), and this identification was confirmed by internal transcribed spacer (ITS) analysis. ITS rDNA of the fungus was amplified using the ITS1 and ITS4 primer set (ITS1: 5'-TCCGTAGGTGAACCTGCGG-3', ITS4: 5'-TCCTCCGCTTATTGATATGC-3'). BLAST analysis of the PCR product showed that the sequence shared 99% identity with the published nucleotide sequences for K. uredinis (Accession No. EU14069). The D1/D2 domain of 28S rDNA was amplified by PCR using the primer pair 5'-ACCCGCTGAAYTTAAGCATAT-3' and 5'-CTTCCTTGGTCCGTGTTTCAAGACGG-3' (1). Phylogenetic analysis using 28S rDNA sequences identified the causal fungus as K. uredinis. The identity of the fungus was confirmed as K. uredinis by DNA sequencing; the sequence was 99% similar to that of other K. uredinis (AF426218, AY745696, DQ354551, and GU058013). To the best of our knowledge, this is the first report of an outbreak of cane and leaf rust on Rubus fruticosus Linné caused by K. uredinis in Korea. References: (1) V. der Auwera et al. FEBS Microbiol. Lett. 338:133, 1994. (2) D. E. Gardner. Plant Dis. 67:963, 1983. (3) G. F. Laundon and A. F. Rainbow. CMI Descriptions of Pathogenic Fungi and Bacteria 202:1, 1969.

First Report of Branch Dieback of Walnut Caused by Neofusicoccum parvum in Korea

Walnut (Juglans sinensis Dode) is an economically important tree in the world, both for its wood and its fruit. Walnut fruits, as rich sources of omega-3 essential fatty acid, are valuable nutritionally. Consumer interest in Korea for walnuts has increased in recent years, and production has increased to 1,042 ha with the Kyoungbuk region consisting of 402 ha (2). In May 2012, lethal dieback disease of walnut tree was detected in two orchards in Andong, Kyoungbuk region, Korea, each with an incidence of 25 to 30%. Disease symptoms included blight and dieback of the stems, flowing resin, dark decay inside the bark of dead twigs, and defoliation. The bark of dead twigs was removed and sliced thinly using a razor blade, and water-mounted, without staining, for observation of fungal structures, if present. Pycnidia were found embedded within the bark of dead twigs and conidia were mostly characterized by fusoid, hyaline, smooth, thin-walled, unicellular and 16.25 to 21.25 μm long and 4.37 to 6.87 μm wide. These characteristics are consistent with those reported previously for Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips (1). Diseased branch tissues collected from the two locations were surface sterilized with 1% NaOCl, rinsed with sterile distilled water, and plated on potato dextrose agar (PDA). The fungal isolates, recovered from the two different orchards, produced white, aerial mycelium and became light gray within a week after incubating plates at 25°C. To confirm the identities of the isolates, the complete internal transcribed spacer (ITS) rDNA of the fungi was amplified and sequenced using PCR. The sequences were compared with other DNA sequences in the GenBank database, using a BLAST search. BLAST analysis of the PCR product showed that the sequence had 99% identity with the nucleotide sequences for N. parvum (JQ411396.1 and GU997688.1). Additionally, the chitin synthase 1 gene was sequenced and analyzed using the BLAST server. The sequence of PCR product had 100% identity with the nucleotide sequences of N. parvum strain CMW9080 chitin synthase 1 gene (EU339501). Thus, both morphological and molecular characters confirmed this species as N. parvum. Pathogenecity tests were performed by inoculating 2-year-old J. sinensis trees. Inoculations consisted of inserting 5-mm-diamter agar plug bearing fresh mycelium of the fungal isolates into the wounds. Within 2 weeks, black lesions appeared on all inoculated plants accompanied by defoliation, whereas no symptoms were observed in the control plants. N. parvum has been reported a member of Botryosphaeriaceae, commonly associated with dieback and cankers of woody plants (1). To our knowledge, this study is the first report of N. parvum as a pathogen of Juglans sinensis in Korea. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) Statistics Korea. Forest Households by Growing Area of Walnut/Total Area. 2010.

Comparison of 2 retrieval devices for heartworm removal in 52 dogs with heavy worm burden

BACKGROUND

For treating dogs with heavy heartworm infection, mechanical removal using various retrieval devices is useful. However, the efficacy and safety of retrieval devices have rarely been studied.

HYPOTHESIS

Catheter-based heartworm removal using 2 retrieval devices (basket and tripod grasping forceps) is efficient and safe for treating dogs with heavy worm burden.

ANIMALS

Fifty-two client-owned dogs with heavy (Class III and IV) worm burden.

METHODS

A retrospective study was performed on 52 dogs, using a catheter-based heartworm removal approach using 2 types of retrieval devices (ie, the basket and the tripod grasping forceps). The efficacy and complications associated with the 2 devices were assessed.

RESULTS

The basket device was used on 22 of the study group dogs, and the tripod grasping forceps was used on 30 of the dogs. The postoperative survival rate was 95.5% for the basket device and 80% for the tripod grasping forceps, but the difference was not statistically significant. The worm number captured per attempt was 3.5 ± 1.7 using the basket device and 1.9 ± 0.85 for the tripod grasping forceps (P < .05). Various complications associated with heartworm removal were noticed with both retrieval devices.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study suggests that catheter-based heartworm removal is not only a relatively safe and efficient therapeutic method in dogs with heavy worm burden, but more efficient using the basket device. Our data do not indicate a clear safety advantage between the 2 devices evaluated, although the survival rate was numerically higher in dogs undergoing a basket intervention.

Effects of electron-cyclotron-resonance-heating-induced internal kink mode on the toroidal rotation in the KSTAR Tokamak

It is observed that the magnitude of the toroidal rotation speed is reduced by the central electron cyclotron resonance heating (ECRH) regardless of the direction of the toroidal rotation. The magnetohydrodynamics activities generally appear with the rotation change due to ECRH. It is shown that the internal kink mode is induced by the central ECRH and breaks the toroidal symmetry. When the magnetohydrodynamics activities are present, the toroidal plasma viscosity is not negligible. The observed effects of ECRH on the toroidal plasma rotation are explained by the neoclassical toroidal viscosity in this Letter. It is found that the neoclassical toroidal viscosity torque caused by the internal kink mode damps the toroidal rotation.

Inversion technique to obtain local rotation velocity and ion temperature from line-integrated measurements for elongated tokamak plasma

An inversion technique is presented to calculate local toroidal and poloidal rotation velocity and ion temperature from line-integrated measurements of impurity lines by a matrix method. The effects of the rotation velocity on the ion temperature are analyzed in particular. An accurate inversion formula for the ion temperature is obtained. Several experimental geometries or configurations of line-integrated diagnostics in tokamaks are presented. For a plasma that is up-down symmetric, both the toroidal rotation velocity and poloidal rotation velocity can be deduced from one special line-integrated measurement.

Upgrades of the high resolution imaging x-ray crystal spectrometers on experimental advanced superconducting tokamak

Two imaging x-ray crystal spectrometers, the so-called "poloidal" and "tangential" spectrometers, were recently implemented on experimental advanced superconducting tokamak (EAST) to provide spatially and temporally resolved impurity ion temperature (T(i)), electron temperature (T(e)) and rotation velocity profiles. They are derived from Doppler width of W line for Ti, the intensity ratio of Li-like satellites to W line for Te, and Doppler shift of W line for rotation. Each spectrometer originally consisted of a spherically curved crystal and a two-dimensional multi-wire proportional counter (MWPC) detector. Both spectrometers have now been upgraded. The layout of the tangential spectrometer was modified, since it had to be moved to a different port, and the spectrometer was equipped with two high count rate Pilatus detectors (Model 100 K) to overcome the count rate limitation of the MWPC and to improve its time resolution. The poloidal spectrometer was equipped with two spherically bent crystals to record the spectra of He-like and H-like argon simultaneously and side by side on the original MWPC. These upgrades are described, and new results from the latest EAST experimental campaign are presented.

Tangential x-ray imaging crystal spectrometer on J-TEXT tokamak

A tangential x-ray imaging crystal spectrometer (XICS) has been developed for the J-TEXT tokamak to measure the ion temperature and the plasma toroidal rotation velocity. The resonance spectral line and its satellites of Ar XVII in the ranges of 3.94 Å-4.0 Å are detected. A spherically bent quartz crystal with 2d = 4.913 Å is used in this system. The crystal has a dimension of 9 cm high and 3 cm wide and the radius of curvature 3823 mm. The XICS is designed to receive emission of Ar XVII from -10 cm to +10 cm region with a spatial resolution of 3.1 cm in the vertical direction considering the parameters of the J-TEXT plasma. The XICS has a tangential angle of 27° with respect to toroidal direction in the magnetic axis. A two-dimensional 100 mm by 300 mm multi-wire proportional counter is applied to detect the spectra.

Standardization of modified right lobe grafts to minimize vascular outflow complications for adult living donor liver transplantation

BACKGROUND

After >2000 adult living donor liver transplants (LDLTs), we observed minimization of the complication rate using case-by-case modification of venous outflow reconstruction in right liver graft (RLG), standardization seeking intend to provide a hemodynamic- based, regeneration-compliant hepatic outflow reconstruction.

METHODS

We retrospectively examined 100 consecutive adult LDLT using modified RLG before and after application of RLG standardization to compare the 6-month incidences of vascular outflow complications.

RESULT

The right hepatic vein stenting rate for first 6 months was 5% in the customized group and 1% in the standardized group (P=.212). The middle hepatic vein stenting rate for first 6 months was 9% in the customized group and 4% in the standardized group (P=.373). The inferior right hepatic vein stenting rate for first 6 months was 12.8% in the customized group and 7.1% in the standardized group (P=.472). The overall 6-month patient survival rate was 94% in the customized group and 95% in the standardized group (P=.867). The overall incidence of significant RLG venous outflow complications was 19% in the customized group and 8% in the standardized group (P=.023).

CONCLUSION

Standardization as a universal graft model seemed to be more effective and feasible than conventional graft customization requiring individualized case-by-case modification.

De novo malignancies after liver transplantation: incidence comparison with the Korean cancer registry

PURPOSE

De novo malignancy is not uncommon after liver transplantation (OLT). We have compared the incidence of novo malignancy following OLT with those among the general Korean population.

METHODS

Between January 1998 and December 2008, 1952 adult OLT were performed, including 1714 living donor and 238 deceased donor grafts whose medical records were retrospectively reviewed.

RESULTS

Among the 1952 patients, 44 (2.3%) showed de novo malignancies after a mean posttransplant period of 41 months. Among the 14 types of malignancy the most frequent was stomach cancer (n = 11; 25.0%), colorectal cancer (n = 9; 20.5%), breast cancer (n = 4; 9.1%), and thyroid cancer (n = 3; 6.8%). These patients underwent aggressive treatment, including surgery, chemotherapy, and radiotherapy, except for one patient with an aggressive primary liver cancer. Over a mean follow-up of 45 months after diagnosis of de novo malignancy, 13 patients (29.5%) died; the overall 3-year patient survival rate was 67.5%. The relative risk of malignancy following OLT was 7.7-fold higher in men and 7.3-fold higher in women than the Korean general population.

CONCLUSIONS

OLT recipients must be checked periodically for de novo malignancy throughout their lives, especially for cancers common in the general population.

Suppression of edge localized modes in high-confinement KSTAR plasmas by nonaxisymmetric magnetic perturbations

Edge localized modes (ELMs) in high-confinement mode plasmas were completely suppressed in KSTAR by applying n=1 nonaxisymmetric magnetic perturbations. Initially, the ELMs were intensified with a reduction of frequency, but completely suppressed later. The electron density had an initial 10% decrease followed by a gradual increase as ELMs were suppressed. Interesting phenomena such as a saturated evolution of edge T(e) and broadband changes of magnetic fluctuations were observed, suggesting the change of edge transport by the applied magnetic perturbations.

Cloning of a Family 11 Xylanase Gene from Bacillus amyloliquefaciens CH51 Isolated from Cheonggukjang

Bacillus amyloliquefaciens CH51, an isolate from cheonggukjang, Korean fermented soyfood, secretes several enzymes into culture medium. A gene encoding 19 kDa xylanase was cloned by PCR. Sequencing showed that the gene encoded a glycohydrolase family 11 xylanase and named xynA. xynAHis, xynA with additional codons for his-tag, was overexpressed in Escherichia coli BL21(DE3) using pET-26b(+). XynAHis was purified using HisTrap affinity column. Km and Vmax of XynAHis were 0.363 mg/ml and 701.1 μmol/min/mg, respectively with birchwood xylan as a substrate. The optimum pH and temperature were pH 4 and 25 °C, respectively. When xynA was introduced into Bacillus subtilis WB600, active XynA was secreted into culture medium.