Role of Serum Pepsinogen II and Helicobacter pylori Status in the Detection of Diffuse-Type Early Gastric Cancer in Young Individuals in South Korea

Background/Aims

The utility of serum pepsinogen (sPG) I and the sPGI/II ratio as biomarkers for screening individuals with gastric cancer (GC) has not been established in Korea. The aim of this study was to define the role of sPG, especially sPGII, in GC screening.

Methods

This study enrolled 2,940 subjects, including patients with GC (n=1,124) or gastric dysplasia (n=353) and controls (n=1,463). Tests to determine sPG levels and Helicobacter pylori (HP) infection status were performed. Area under the curve and receiver operating characteristic curve were calculated to identify the optimal cutoff values for sPG. The usefulness of sPG levels for the detection of GC and gastric dysplasia was validated by multivariate logistic regression.

Results

The sPGI/II ratio was associated with the risk of gastric dysplasia and advanced-stage intestinal-type GC (IGC). In contrast, sPGII was associated with the risk of early-stage diffuse-type GC (DGC). Significantly higher risk was indicated by an sPGI/II ratio <3 for gastric dysplasia and advanced-stage IGC and by sPGII levels ≥20 µg/L for early-stage DGC. Positive HP status showed a stronger association with DGC than with IGC. When sPGII level and HP status were combined, the prevalence of DGC was higher in the ≥20 µg/L sPGII and HP-positive group. Age younger than 40 years was strongly related to early-stage DGC, especially in females (odds ratio, 21.00; p=0.006).

Conclusions

sPGII ≥20 ng/mL and positive HP status suggest a risk of early-stage DGC, particularly in young adult females in South Korea.

Vertebral fracture is associated with myocardial infarction in incident hemodialysis patients: a Korean nationwide population-based study

Chronic kidney disease (CKD)-mineral and bone disorder suggests that fragile bone and vascular disorder might be connected closely in CKD patients. In this study, fracture event was significantly associated with myocardial infarction (MI) in end-stage renal disease patients on hemodialysis (HD), especially for vertebral fractures.

INTRODUCTION

CKD-mineral and bone disorder is characterized by biochemical abnormalities, bone disorders, and vascular calcification. We aimed to verify the association between fracture and MI in CKD patients.

METHODS

Records for incident CKD stage 3 to 5 patients and patients who initiated HD between July 2014 and June 2018 were retrieved from the Korean Health Insurance Review & Assessment Service Database. Fractures were defined using diagnostic codes and were classified into vertebral, femoral, and other site fractures. MI was defined using a combination of MI diagnostic codes and related procedure codes. Multiple logistic regressions and 1:1 propensity score matching analysis were conducted.

RESULTS

A total of 38,935 patients (HD, 11,379; pre-dialysis CKD, 27,556) were included in this study. A total of 5,057 (13.0%) patients experienced fracture, and 1,431 (3.7%) patients had MI. Multiple logistic regression analysis showed that fracture was significantly associated with MI in the HD group (odds ratio (OR) 1.34, P = 0.024), but not in the pre-dialysis CKD group (OR 1.04, P = 0.701). After propensity score matching for age, gender, and diabetes mellitus between patients with and without fracture, fracture still significantly correlated with MI in HD patients (OR 1.47, P = 0.034) but not in patients with pre-dialysis CKD (OR 1.04, P = 0.751). Subgroup analysis by fracture site found that vertebral fracture was associated with MI in HD patients (OR 2.11, P = 0.024), but femoral or other site fractures were not.

CONCLUSION

In HD patients, fracture was significantly associated with MI, especially for vertebral fractures patients.

[Development of Koreans Gut Quotient Measurement Scales]

Background/Aims

The aim of this study was to develop 'Koreans Gut Quotient Measurement Scales (GQ)', in which Koreans respond to questionnaires about the subjective feelings and symptoms of their intestinal health status.

Methods

Among 66 items pooled from previous studies and 4 items that were added following a focus group interview, 15 items were chosen using the Delphi survey. The content validity was evaluated using the content validity ratio. Data collected from 1,120 people from the general public in Korea were analyzed to verify the reliability and validity of GQ.

Results

The finalized GQ consisted of 17 items (including two exploratory measurement items) that were classified into three independent factors based on exploratory factor analysis (EFA): 'perceived intestine discomfort', 'bowel movement discomfort', and 'bowel movement control discomfort'. The discriminant and convergent validity of GQ were identified using EFA, reliability test, and confirmatory factor analysis. In addition, the criterion-related validity of GQ was identified using correlation and multiple regression analysis.

Conclusions

The GQ, which is a simplified intestinal health index developed based on an easy questionnaire for the public to understand, can be used as a tool for the public to evaluate their own intestinal health and determine when to visit clinics.

The prevalence of histologic atrophy and intestinal metaplasia in the corpus has decreased over 15 years in females in the Korean population

BACKGROUND

The aim of this study was to investigate the trends of atrophy and intestinal metaplasia (IM) in 2002 subjects without significant gastroduodenal diseases.

MATERIALS AND METHODS

A total of 2002 subjects were prospectively enrolled and divided into three periods (2003-2007, 2008-2012, and 2013-2018). Trends of H pylori and atrophy/IM scored by Updated Sydney System were analyzed according to sex, and multivariate logistic analysis was performed for the risk factors for atrophy/IM.

RESULTS

H pylori-negative and H pylori-positive subjects were 1220 (61.0%) and 782 (38.0%), respectively. H pylori positivity decreased from 149/303 (49.2%), 207/515 (40.2%) and 426/1184 (36.0%), in the three periods, respectively (P < 0.001). The prevalence of atrophy (P < 0.001) and IM in the corpus (P < 0.001) significantly decreased over 15 years in females, but not in males. The mean grade of atrophy and IM was higher in males (0.36 and 0.51) than in females (0.28 and 0.41) in the corpus (P = 0.027) and in the antrum (P = 0.006), respectively. Similarly, the mean grade of IM in males (0.34) was higher in females (0.19; P < 0.001) in the corpus. Multivariate analysis showed that old age, study period, and H pylori were statistically significant in atrophy of antrum and corpus, and IM in the corpus. In cases of IM of antrum, old age, H pylori, and smoking were statistically significant.

CONCLUSION

A significant decrease in atrophy and IM in the corpus in females over 15 years suggests sex- or gender-specific characteristics.

Dispersion in Ferroelectric Switching Performance of Polycrystalline Hf0.5Zr0.5O2 Thin Films

Interests in nanoscale integrated ferroelectric devices using doped HfO₂-based thin films are actively reviving in academia and industry. The main driving force for the formation of the metastable non-centrosymmetric ferroelectric phase is considered to be the interface/grain boundary energy effect of the small grains in polycrystalline configuration. These small grains, however, can invoke unfavorable material properties, such as nonuniform switching performance. This study provides an in-depth understanding of such aspects of this material through careful measurement and modeling of the ferroelectric switching kinetics. Various previous switching models developed for conventional ferroelectric thin-film capacitors cannot fully account for the observed time- and voltage-dependent switching current evolution. The accurate fitting of the experimental results required careful consideration of the inhomogeneous field distribution across the electrode area, which could be acquired by an appropriate mathematical formulation of polarization as a function of electric field and time. Compared with the conventional polycrystalline Pb(Zr,Ti)O₃ film, the statistical distribution of the local field was found to be three times wider. The activation field and characteristic time for domain switching were larger by more than 1 order of magnitude. It indicates that doped HfO₂ is inhomogeneous and "hard" ferroelectric material compared with conventional perovskite-based ferroelectrics.

Atomic layer deposition of GeSe films using HGeCl3 and [(CH3)3Si]2Se with the discrete feeding method for the ovonic threshold switch

The ovonic threshold switch (OTS) based on the voltage snapback of amorphous chalcogenides possesses several desirable characteristics: bidirectional switching, a controllable threshold voltage (V _th) and processability for three-dimensional stackable devices. Among the materials that can be used as OTS, GeSe has a strong glass-forming ability (∼350 °C crystallization temperature), with a simple binary composition. Described herein is a new method of depositing GeSe films through atomic layer deposition (ALD), using HGeCl₃ and [(CH₃)₃Si]₂Se as Ge and Se precursors, respectively. The stoichiometric GeSe thin films were formed through a ligand exchange reaction between the two precursor molecules, without the adoption of an additional reaction gas, at low substrate temperatures ranging from 70 °C-150 °C. The pseudo-saturation behavior required a long time of Ge precursor injection to achieve the saturation growth rate. This was due to the adverse influence of the physisorbed precursor and byproduct molecules on the efficient chemical adsorption reaction between the precursors and reaction sites. To overcome the slow saturation and excessive use of the Ge precursor, the discrete feeding method (DFM), where HGeCl₃ is supplied multiple times consecutively with subdivided pulse times, was adopted. DFM led to the saturation of the GeSe growth rate at a much shorter total injection time of the Ge precursor, and improved the film density and oxidation resistance properties. The GeSe film grown via DFM exhibited a short OTS time of ∼40 ns, a ∼10⁷ ON/OFF current ratio, and ∼10⁴ selectivity. The OTS behavior was consistent with the modified Poole-Frenkel mechanism in the OFF state. In contrast, the similar GeSe film grown through the conventional ALD showed a low density and high vulnerability to oxidation, which prevented the OTS performance. The ALD method of GeSe films introduced here will contribute to the fabrication of a three-dimensionally integrated memory as a selector device for preventing sneak current.

Balancing the Source and Sink of Oxygen Vacancies for the Resistive Switching Memory

The high nonuniformity and low endurance of the resistive switching random access memory (RRAM) are the two major remaining hurdles at the device level for mass production. Incremental step pulse programming (ISPP) can be a viable solution to the former problem, but the latter problem requires material level innovation. In valence change RRAM, electrodes have usually been regarded as inert (e.g., Pt or TiN) or oxygen vacancy (V_O) sources (e.g., Ta), but different electrode materials can serve as a sink of V_O. In this work, an RRAM using a 1.5 nm-thick Ta₂O₅ switching layer is presented, where one of the electrodes was V_O-supplying Ta and the other was either inert TiN or V_O-sinking RuO₂. Whereas TiN could not remove the excessive V_O in the memory cell, RuO₂ absorbed the unnecessary V_O. By carefully tuning (balancing) the capabilities of V_O-supplying Ta and V_O-sinking RuO₂ electrodes, an almost invariant ISPP voltage and a greatly enhanced endurance performance can be achieved.

Nociceptive Memristor

The biomimetic characteristics of the memristor as an electronic synapse and neuron have inspired the advent of new information technology in the neuromorphic computing. The application of the memristors can be extended to the artificial nerves on condition of the presence of electronic receptors which can transfer the external stimuli to the internal nerve system. In this work, nociceptor behaviors are demonstrated from the Pt/HfO₂ /TiN memristor for the electronic receptors. The device shows four specific nociceptive behaviors; threshold, relaxation, allodynia, and hyperalgesia, according to the strength, duration, and repetition rate of the external stimuli. Such nociceptive behaviors are attributed to the electron trapping/detrapping to/from the traps in the HfO₂ layer, where the depth of trap energy level is ≈0.7 eV. Also, the built-in potential by the work function mismatch between the Pt and TiN electrodes induces time-dependent relaxation of trapped electrons, providing the appropriate relaxation behavior. The relaxation time can take from several milliseconds to tens of seconds, which corresponds to the time span of the decay of biosignal. The material-wise evaluation of the electronic nociceptor in comparison with other material, which did not show the desired functionality, Pt/Ti/HfO₂ /TiN, reveals the importance of careful material design and fabrication.

Dog and Cat Allergies and Allergen Avoidance Measures in Korean Adult Pet Owners Who Participated in a Pet Exhibition

Purpose

This study evaluated dog and cat allergies and their association with allergen avoidance measures in Korean adults.

Methods

The study population consisted of 537 adults who currently kept dogs or cats and participated in a pet exhibition in Korea. The subjects were asked to complete questionnaires regarding pet ownership, allergen avoidance, and allergy symptoms, and underwent skin prick tests. They were considered to have a dog or cat allergy if they suffered from one or more of allergy symptoms during contact with their pets.

Results

In total, 103 of 407 dog owners (25.3%) and 45 of 130 cat owners (34.6%) had a dog or cat allergy, respectively. Dog owners kept 1.3±1.5 dogs; this number did not differ according to the presence of dog allergy. Dog owners with a dog allergy had owned their dogs longer than those without (88.0±72.0 vs 67.5±72.7 months, P<0.05). Cat owners kept 2.1±3.6 cats; this number did not differ according to the presence of cat allergy, nor did the duration of cat ownership. Cat owners with a cat allergy had facial contact and slept with their cats less frequently (8.6±11.9 vs 18.3±27.0 times/day, P<0.01; 71.1% vs 81.2%, P<0.05); however, they had their cats shaved and beds cleaned less frequently than those without (1.8±3.3 vs 3.2±4.4 times/year, P<0.05; 1.5±1.5 vs 3.9±6.0 times/month, P<0.01).

Conclusions

Cat owners with a cat allergy tried to minimize contact with their cats, but efforts to avoid indoor cat allergens were lower than those without. In comparison, dog owners with a dog allergy had kept their dogs for longer time than those without; however, current contact with their dogs and allergen avoidance measures did not differ between the 2 groups.

The current limit and self-rectification functionalities in the TiO2/HfO2 resistive switching material system

To replace the present NAND flash memory, resistance switching random access memory (ReRAM), which has both memory and selection functionalities with a simple metal-insulator-metal structure should be implemented. To accomplish this goal, ReRAM must be self-rectifying, low-power-consuming, and highly uniform, and it must have reliable states. In this work, the Pt/TiO₂/HfO_2-x/TiN resistive switching memory structure showed self-rectifying resistive switching behavior with unprecedented unique I-V curves. This is named "self-current saturation," which can give an extremely uniform variation of the low resistance state. The plausible reasons for the whole switching behavior, including the unique I-V curves, in this material system are presented herein. The diffusion of Ti along the grain boundaries of HfO₂ down to the bottom electrode TiN and the defect formation within the HfO₂ layer near the TiO₂/HfO₂ interface made the resistance switching device have the characteristics of both the unidirectional diode and electronic bipolar switching devices.

A study of the transition between the non-polar and bipolar resistance switching mechanisms in the TiN/TiO2/Al memory

Thermochemical and electronic trapping/detrapping mechanism-based resistance switching in TiO2 is one of the most extensively researched topics in the field of resistance-switching random access memory (ReRAM). In this study, the subtle correlation between the formation and rupture of the Magnéli-based conducting filament (CF), which is the mechanism of non-polar thermochemical-reaction-based switching, and the electron trapping/detrapping at the defect centers, which is the mechanism of bipolar electronic switching, is examined in detail. The chemical interaction between the TiN top electrode and the TiO2 layer generates a stable and immobile electron trapping layer, which is called a "switching layer", whereas the thin region between the just-mentioned switching layer and the remaining Magnéli CF after the thermochemical reset comprises a non-switching layer. The seemingly very complicated switching behavior with respect to the bias polarity, compliance current, and detailed biasing sequence could be reasonably explained by the phenomenological model based on the combined motions of the CF, switching layer, and non-switching layer. Light-induced detrapping experiments further supplement the suggested switching model.

ROS1 Kinase Inhibitors for Molecular-Targeted Therapies

ROS1 is a pivotal transmembrane receptor protein tyrosine kinase which regulates several cellular processes like apoptosis, survival, differentiation, proliferation, cell migration, and transformation. There is increasing evidence supporting that ROS1 plays an important role in different malignancies including glioblastoma, colorectal cancer, gastric adenocarcinoma, inflammatory myofibroblastic tumor, ovarian cancer, angiosarcoma, and non small cell lung cancer; thus, ROS1 has become a potential drug discovery target. ROS1 shares about 49% sequence homology with ALK primary structure; therefore, wide range of ALK kinase inhibitors have shown in vitro inhibitory activity against ROS1 kinase. After Crizotinib approval by FDA for the management of ALK-rearranged lung cancer, ROS1-positive tumors have been focused. Although significant advancements have been achieved in understanding ROS1 function and its signaling pathways plus recent discovery of small molecules modulating ROS1 protein, a vital need of medicinal chemistry efforts is still required to produce selective and potent ROS1 inhibitors as an important therapeutic strategy for different human malignancies. This review focuses on the current knowledge about different scaffolds targeting ROS1 rearrangements, methods to synthesis, and some biological data about the most potent compounds that have delivered various scaffold structures.

Uniform Self-rectifying Resistive Switching Behavior via Preformed Conducting Paths in a Vertical-type Ta2O5/HfO2-x Structure with a Sub-μm(2) Cell Area

To replace or succeed the present NAND flash memory, resistive switching random access memory (ReRAM) should be implemented in the vertical-type crossbar array configuration. The ReRAM cell must have a highly reproducible resistive switching (RS) performance and an electroforming-free, self-rectifying, low-power-consumption, multilevel-switching, and easy fabrication process with a deep sub-μm(2) cell area. In this work, a Pt/Ta2O5/HfO2-x/TiN RS memory cell fabricated in the form of a vertical-type structure was presented as a feasible contender to meet the above requirements. While the fundamental RS characteristics of this material based on the electron trapping/detrapping mechanisms have been reported elsewhere, the influence of the cell scaling size to 0.34 μm(2) on the RS performance by adopting the vertical integration scheme was carefully examined in this work. The smaller cell area provided much better switching uniformity while all the other benefits of this specific material system were preserved. Using the overstressing technique, the nature of RS through the localized conducting path was further examined, which elucidated the fundamental difference between the present material system and the general ionic-motion-related bipolar RS mechanism.

Time-Dependent Negative Capacitance Effects in Al2O3/BaTiO3 Bilayers

The negative capacitance (NC) effects in ferroelectric materials have emerged as the possible solution to low-power transistor devices and high-charge-density capacitors. Although the steep switching characteristic (subthreshold swing < sub-60 mV/dec) has been demonstrated in various devices combining the conventional transistors with ferroelectric gates, the actual applications of the NC effects are still some way off owing to the inherent hysteresis problem. This work reinterpreted the hysteretic properties of the NC effects within the time domain and demonstrated that capacitance (charge) boosting could be achieved without the hysteresis from the Al2O3/BaTiO3 bilayer capacitors through short-pulse charging. This work revealed that the hysteresis phenomenon in NC devices originated from the dielectric leakage of the dielectric layer. The suppression of charge injection via the dielectric leakage, which usually takes time, inhibits complete ferroelectric polarization switching during a short pulse time. It was demonstrated that a nonhysteretic NC effect can be achieved only within certain limited time and voltage ranges, but that these are sufficient for critical device applications.

Effect of weed extracts against pulse beetle, Callosobruchus chinensis L. (Coleoptera: Bruchidae) of mung bean

The n-hexane extracts of the weeds ‘bhatpata’ Clerodendrum viscosum, ‘kashiature’ Cassia tora, ‘dhakishak’ Dryoptris filix-max, ‘bonmorich’ Croton bonpalandianum and ‘ghagra’ Xanthium strumarium were used to evaluate their effectiveness for suppressing pulse beetle, Callosobruchus chinensis reared on mung bean Vigna radiata grains. The investigations were done with 1, 2 and 4% n-hexane extracts of the weeds and an untreated control. The weed extracts exhibited considerable effectiveness which varied with weed species, concentrations and exposure durations. The higher concentrations showed the higher rate of insect mortality, fecundity, adult emergence inhibition, and grain protection. The LC50 values of the extracts ranged from 5.3 to 7.8, 4.7 to 6.5 and 4.1 to 6.0 g/100 ml at 24, 48 and 72 hours after treatment, respectively. The fecundity inhibition varied from 31.7 to 78.7%, adult emergence inhibition from 33.8 to 81.1%, and grain damage inhibition from 10.3 to 60.1% when ‘bhatpata’ with concentration of 1 g/100 ml and ‘ghagra’ with concentration of 4g/100 ml were applied, respectively. Among the tested weeds, ghagra (4g/100 ml) showed better efficacy against C. chinensis compared to other tested extracts and may be suggested to control pulse beetle and protection of mung bean grains.Bangladesh J. Agril. Res. 41(1): 75-84, March 2016

Pt/Ta2 O5 /HfO2- x /Ti resistive switching memory competing with multilevel NAND flash

Pt/Ta2 O5 /HfO2- x /Ti resistive switching memory with a new circuit design is presented as a feasible candidate to succeed multilevel-cell (MLC) NAND flash memory. This device has the following characteristics: 3 bit MLC, electroforming-free, self-rectifying, much higher cell resistance than interconnection wire resistance, low voltage operation, low power consumption, long-term reliability, and only an electronic switching mechanism, without an ionic-motion-related mechanism.

Mixing-sequence-dependent nucleic acid complexation and gene transfer efficiency by polyethylenimine

Polyplexes, complexed nucleic acids by cationic polymers, are the most common forms of nonviral gene delivery vectors. In contrast to a great deal of efforts in synthesizing novel cationic polymers and exploring their extracellular and intracellular delivery pathways, polyplex preparation methods of mixing nucleic acids and cationic polymers are often overlooked. In this study, the mixing sequence, that is adding nucleic acids to polymers or vice versa, was found to greatly affect complexation of both plasmid DNA and siRNA, polyplexes' size, and polyplexes' surface charge, which all collaboratively affected the transfection efficiency and cytotoxicity. Adding polyethylenimine (PEI), the most conventionally used standard in nonviral gene delivery, to plasmid DNA and siRNA resulted in larger polyplexes, higher gene expression and silencing, but higher cytotoxicity than polyplexes prepared in the reverse order. Based on the experimental results, the authors developed a model that gradual addition of cationic polymers (e.g., PEI) to nucleic acids (e.g., plasmid DNA and siRNA) incorporates more copies of nucleic acids in larger polyplexes in a smaller number, results in higher gene expression and silencing levels in transfected cells, and generates higher cytotoxicity by leaving more free polymers upon complete mixing than the other mixing sequence. The proposed model can be explored using a broad range of cationic polymers and nucleic acids, and provide insightful information about how to prepare polyplexed nonviral vectors for efficient and safe gene delivery.

A lazy learning-based QSAR classification study for screening potential histone deacetylase 8 (HDAC8) inhibitors

Histone deacetylases 8 (HDAC8) is an enzyme repressing the transcription of various genes including tumour suppressor gene and has already become a target of human cancer treatment. In an effort to facilitate the discovery of HDAC8 inhibitors, two quantitative structure-activity relationship (QSAR) classification models were developed using K nearest neighbours (KNN) and neighbourhood classifier (NEC). Molecular descriptors were calculated for the data set and database compounds using ADRIANA.Code of Molecular Networks. Principal components analysis (PCA) was used to select the descriptors. The developed models were validated by leave-one-out cross validation (LOO CV). The performances of the developed models were evaluated with an external test set. Highly predictive models were used for database virtual screening. Furthermore, hit compounds were subsequently subject to molecular docking. Five hits were obtained based on consensus scoring function and binding affinity as potential HDAC8 inhibitors. Finally, HDAC8 structures in complex with five hits were also subjected to 5 ns molecular dynamics (MD) simulations to evaluate the complex structure stability. To the best of our knowledge, the NEC classification model used in this study is the first application of NEC to virtual screening for drug discovery.

Safety of transorally-inserted anvil for esophagojejunostomy in laparoscopic total gastrectomy

BACKGROUND

To assess the safety of transorally-inserted anvil (TOA) for use during esophagojejunostomy (EJ) reconstruction during laparoscopic total gastrectomy (LTG).

METHODS

Between March 2009 and December 2011, 39 consecutive open total gastrectomies (OTGs) and 36 LTGs using TOA for gastric cancer were comparatively evaluated. We investigated postoperative complications, using the Clavien-Dindo classification. To evaluate the effect of a learning period in using TOA for LTG, we also investigated shifts in the patterns of complications and changes in total operation time over the course of the study.

RESULTS

The patient characteristics at baseline were not different between both groups, except for the extent of lymphadenectomy (P < 0.001) and depth of tumor invasion (P = 0.003). Multivariate analysis revealed that TOA usage elevated the occurrence of infectious complications significantly (OR = 3.32, P = 0.042), but was not associated with EJ-related complications. TOA usage did not need a learning period for the length of time required to complete the operation, or the likelihood of developing an EJ-related or infectious complication.

CONCLUSIONS

TOA use for EJ during LTG is relatively simple and easy enough not to require a learning period for surgeons. This procedure did not elevated the occurrence of EJ-related complications compared to circular stapling in open surgery, but it does require special prevention efforts to avoid infectious complications.

Hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation: incidence, risk factors, and outcome

Four hundred and sixty-seven hematopoietic stem cell transplantations (HSCTs) (217 autologous and 250 allogeneic HSCT) were performed in 374 children at four pediatric HSCT centers in Korea from January 2005 to December 2007. Among 467 transplants, veno-occlusive disease (VOD) developed in 72 transplants (15.4%) at a median of 10 days after HSCT. Multivariate analysis showed that BU or TBI-containing regimen (P=0.002), VOD prophylaxis without lipo-prostaglandin E1 (PGE1) (P=0.012), number of previous HSCT (P=0.014), and pretransplant serum ferritin (P=0.018) were independent risk factors for developing VOD. Mean serum ferritin levels were significantly higher in HSCT with VOD (2109.6+/-2842.5 ng/ml) than in HSCT without VOD (1315.9+/-1094.4 ng/ml) (P<0.001). The relative risk of death within 100 days of HSCT in transplants with VOD compared with transplants without VOD was 3.39 (confidence interval: 1.78-6.45). Our results suggest that lipo-PGE1 might have a protective effect against the development of VOD, and pretransplant serum ferritin could act as a risk factor for VOD. A larger prospective study is needed to confirm a possible role of lipo-PGE1 and iron chelation therapy in reducing the incidence of VOD.

Limits on interactions between weakly interacting massive particles and nucleons obtained with CsI(Tl) crystal detectors

The Korea Invisible Mass Search (KIMS) experiment presents new limits on the weakly interacting massive particle (WIMP)-nucleon cross section using data from an exposure of 3409 kg.d taken with low-background CsI(Tl) crystals at the Yangyang Underground Laboratory. The most stringent limit on the spin-dependent interaction for a pure proton case is obtained. The DAMA signal region for both spin-independent and spin-dependent interactions for the WIMP masses greater than 20 GeV/c2 is excluded by the single experiment with crystal scintillators.

Observation of large CP violation and evidence for direct CP violation in B0-->pi(+)pi(-) decays

We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value.

Observation of B --> J/psi K(1)(1270)

We report the first observation of the exclusive decay process B-->J/psi K(1)(1270) using a sample of 11.2M BB macro meson pairs collected in the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. We measure branching fractions of B[B(0)-->J/psi K(0)(1)(1270)] = (1.30+/-0.34+/-0.32) x 10(-3) and B[B(+)-->J/psi K(+)(1)(1270)] = (1.80+/-0.34+/-0.39) x 10(-3), where the first error is statistical and the second is systematic. These modes constitute approximately 15% of the total number of B-->J/psi X decays. No evidence is seen for B-->J/psi K(1)(1400) and we set an upper limit for this branching fraction.

Observation of Cabibbo suppressed B --> D(*)K- decays at Belle

We report observations of the Cabibbo suppressed decays B-->D((*))K- using a 10.4 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B--->D0K-)/B(B--->D0pi(-)) = 0.079+/-0.009+/-0.006, B(B(0)-->D+K-)/B(B(0)-->D+pi(-)) = 0.068+/-0.015+/-0.007, B(B--->D(*0)K-)/B(B--->D(*0)pi(-)) = 0.078+/-0.019+/-0.009, and B(B(0)-->D(*+)K-)/B(B(0)-->D(*+)pi(-)) = 0.074+/-0.015+/-0.006. These are the first observations of the B-->D+K-, D(*0)K-, and D(*+)K- decay processes.

Observation of large CP violation in the neutral B meson system

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.

Renal biopsy in elderly patients: clinicopathological correlation in 117 Korean patients

AIM

In the elderly with renal disease, the clinical presentations are frequently inconsistent with the pathologic findings. We tried to clarify the differences in pathological findings between the young and the elderly, in Korea and in Western countries, and the usefulness of a percutaneous renal biopsy in the elderly with renal disease.

PATIENTS AND METHODS

We analyzed the clinical presentations and spectrums of renal histopathology by reviewing medical records and renal biopsy reports retrospectively in 117 Korean patients aged 60 years or more with renal disease.

RESULTS

85 patients had primary renal disease. The remaining 32 patients had renal diseases associated with systemic conditions. Out of the 85 patients with primary renal disease, 61 cases presented as idiopathic nephrotic syndrome. Compared with renal biopsy results of younger adult patients (age 15-59, n = 1,908), membranous nephropathy, crescentic glomerulonephritis, membranoproliferative glomerulonephritis, amyloidosis, light chain disease, and thrombotic thrombocytopenic purpura were more prevalent, but IgA nephropathy and lupus nephritis were less common in the elderly patients. In clinical presentation, nephrotic syndrome and rapidly progressive renal failure were more prevalent, but asymptomatic urinary abnormality was less common in elderly patients. The responsiveness to treatment was good in elderly patients with minimal-change lesion (complete remission in all patients) but poor in crescentic glomerulonephritis, IgA nephropathy, and membranoproliferative glomerulonephritis. From the above findings, the clinical presentation, patterns of histopathology and responsiveness to treatment of elderly Korean patients were similar to those of the younger Korean control group and the Western elderly group.

CONCLUSION

Percutaneous renal biopsy is a useful diagnostic aid and can be used as a therapeutic guideline even in elderly patients with renal disease.

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S)

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

Measurement of the CP violation parameter sin2 phi(1) in B(0)(d) meson decays

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

Impact of cell growth morphology on retroviral transduction: effect of contact inhibition

Retrovirus-mediated gene transfer is one of the most commonly used methods to deliver, integrate, and express the gene of interest because the retrovirus can insert the desired gene into the chromosome of the target cells with high stability. However, to deliver the gene successfully, the retrovirus requires active division to integrate reversely transcribed DNA into the chromosome of target cells. In this study, we focused on the effect of cell-cell contact inhibition on the efficiency of retroviral transduction with two anchorage-dependent cell lines: NIH 3T3 and 293 cells. These two cell lines have very different cell morphologies and growth patterns on surfaces. Human embryonic kidney epithelial 293 cells tend to stick together after dividing, while NIH 3T3 cells migrate to occupy available surface and spread. Experimental data indicate that the abatement of the transduction rate of 293 cells was initiated in the early stage of the culture, whereas effect of contact inhibition of NIH 3T3 cells on the transduction rate became dominating at the end of the culture period. Experimental results were also quantitatively illustrated by plotting normalized multiplicity of infection (MOI) versus normalized cell density. According to the outcomes, cell inoculation density plays an important role in optimizing the retroviral transduction rate. The optimal time of retroviral transduction should be confined to the accelerating growth phase for 293 cells and at the exponential growth phase for NIH 3T3 cells. The implication drawn from this study is that contact inhibition effect on retroviral transduction should be taken into account for large-scale gene transfer systems such as the microcarrier bioreactor.

Enhanced retroviral transduction of 293 cells cultured on liquid-liquid interfaces

In clinical research, retrovirus-mediated gene therapy is one of the most commonly used methods to deliver and express the gene of interest due its ability to allow for stable gene integration into the chromosomes of target cells. To elevate the efficiency of viral transduction, several restrictions, such as low virus-cell encounters and the necessity for cell division, must be improved. In this study, we focused on the possibility of accelerating cell division and the ensuing increment of viral transduction on flexible substrata. Perfluorocarbon FC-40 was harnessed to form a liquid-liquid interface with culture medium. Enhanced green fluorescence protein (EGFP) was employed as the marker gene to quickly illustrate the percentage of viral infection. The results indicate that the gene transfer efficiency to 293 cells cultured on protein-precoated liquid-liquid interfaces was higher than in cells cultured on rigid polystyrene surfaces. This increased transduction rate on the liquid-liquid interface is consistent with the acceleration of division of 293 cells on a flexible interface, which exhibited less adhesiveness. The effect of cell-cell contact inhibition on the rate of gene transduction is also addressed in this study.

Nonocclusive mesenteric ischemia in a patient on maintenance hemodialysis

Nonocclusive mesenteric ischemia (NOMI) is known to occupy about 25% to 60% of intestinal infarction. NOMI has been reported to be responsible for 9% of the deaths in the dialysis population and the postulated causes of NOMI include intradialytic hypotension, atherosclerosis and medications, such as diuretics, digitalis and vasopressors. Clinical manifestations, such as fever, diarrhea and leukocytosis, are nonspecific, which makes early diagnosis of NOMI very difficult.

CASE

A 66-year-old woman on maintenance hemodialysis for 5 years was admitted with syncope, abdominal pain and chilly sensation. Since 7 days prior to admission, blood pressure on the supine position during hemodialysis had frequently fallen to 80/50 mmHg. Four days later, she complained of progressive abdominal pain. Rebound tenderness and leukocytosis (WBC 13900/mm3) with left shift were noted. Stool examination was positive for occult blood. Abdominal CT scan showed a distended gall bladder with sludge. Under the impression of acalculous cholecystitis, she was operated on. Surgical and pathologic findings of colon colon were compatible with NOMI. Because of recurrent intradialytic hypotension, we started midodrine 2.5 mg just before hemodialysis and increased the dose up to 7.5 mg. After midodrine therapy, blood pressure during dialysis became stable and the symptoms associated with hypotension did not recur.

CONCLUSION

As NOMI may occur within several hours or days after an intradialytic hypotensive episode, abdominal pain should be carefully observed and NOMI should be considered as a differential diagnosis. In addition, we suggest that midodrine be considered to prevent intradialytic hypotensive episodes.

ACE gene polymorphism and renal responsiveness to ACE inhibitors in IgA nephropathy patients

We examined the renal responsiveness to ACE inhibitor in IgA nephropathy (IgAN) patients according to the grouping of ACE gene polymorphism. Sixty one patients diagnosed as IgAN by renal biopsy and prescribed with ACE inhibitors were enrolled. Genomic DNA was extracted from whole blood and PCR was performed. The I/D polymorphism was determined by the presence of the 287 bp fragment in intron 16 of chromosome 17. During the follow-up period (mean; 44.6 months, median: 44.5 months, 5 to 113 months), the blood pressure of 61 patients was controlled below 130/80 mmHg. The renal responsiveness was determined by the degree of changes of proteinuria at 12 months after initiation of ACE inhibitors and by the slope of reciprocal variation of the serum creatinine against follow-up duration ¿(1/Cr2-1/Cr1)/durations¿. The distribution of the II, ID and DD genotype among 61 patients was 21, 16 and 24 patients, respectively. There were no differences among three genotypes in age, sex, the number of patients with initial blood pressure over 140/90 mmHg, initial serum creatinine level, the number of patients with initial azotemia (> 1.4 mg/dL) and with initial 24-hr proteinuria amount over 2.0 g. Significant anti-proteinuric effect of ACE inhibitor was found in IgAN (p = 0.001), but no significant difference was found among genotypes. Significant difference (p = 0.011) was noticed between II type and DD type in the slope of reciprocal variation of the serum creatinine against follow-up duration. In conclusion, efficacy of ACE inhibitors on renal function preservation in IgAN was more pronounced in DD genotype than II genotype.

Homocyst(e)ine and atherosclerosis in patients on chronic hemodialysis

Hyperhomocyst(e)inemia is an established risk factor for atherosclerosis. We performed this study to identify the correlating variables and risk factors for atherosclerosis, as measured by the atherosclerotic score (AS), and to determine the relative risk for cardiovascular disease in relation to plasma homocyst(e)ine levels in patients on chronic hemodialysis. We evaluated and measured 61 patients on chronic hemodialysis for clinical and biochemical parameters including atherosclerotic score (AS) and plasma homocyst(e)ine. We divided patients into high and low groups, first, by the mean AS, and second, by the median value of plasma total homocyst(e)ine levels. Then we compared the variables between the two groups. Out of the 61 patients, the median plasma total homocyst(e)ine level was 24.4 micromol/L (mean+/-SD, 27.7+/-17.4; range, 9.8-127.4 micromol/L), and the median AS was 5 (mean+/-SD, 6.2+/-2.8; range, 3-13) out of a possible 20 points. AS was significantly correlated with plasma total homocyst(e)ine levels (r=0.37) and age (r=0.67). Through multivariate analysis, plasma total homocyst(e)ine level and age were determined as significant risk factors for the high-AS group (p<0.05). However, plasma total homocyst(e)ine level did not correlate with age (p>0.05). Eighteen of the 61 patients, presented with cardiovascular disease until the present study, had an AS>6. Cardiovascular disease was found more often in the high-homocyst(e)ine group (>24.4 micromol/L) than in the low-homocyst(e)ine group (odds ratio, 9.3; 95% confidence interval, 2.3-37.4). Regardless of age, hyperhomocyst(e)inemia (especially homocyst(e)ine levels >24.4 micromol/L) is a risk factor that can be modified for the development of cardiovascular disease in patients on chronic hemodialysis.

Sjögren's syndrome with acute renal failure

We experienced a 65-year-old woman with Sjögren's syndrome who presented with acute renal failure, hypergammaglobulinemia with monoclonal gammopathy, and hypocomplementemia. She improved with steroid pulse therapy (methylprednisolone 0.5 g/day for 3 days). This patient had also sensorineural hearing loss, symmetric sensory polyneuropathy of legs, and interstitial lung disease. Ten months after recovery from acute renal failure, low-dose oral prednisolone (0.1 mg/kg/day) was withdrawn. On the third month of steroid withdrawal, acute renal failure recurred with hypergammaglobulinemia, hyperamylasemia, and autoimmune cholangitis-like biochemical derangements, which also responded to steroid pulse therapy (methylprednisolone 0.3 g/day for 3 days). When we would withdraw steroid in a patient with visceral involvement of Sjögren's syndrome, we should consider multiple clinical and laboratorial variables, including erythrocyte sedimentation rate, serum levels of IgG, total protein, C3/C4, CRP, amylase, lipase, and alkaline phosphatase. We report this case which exhibited various unusual manifestations with a review of literature.

A case of Wegener's granulomatosis complicated by diffuse pulmonary hemorrhage and thrombotic thrombocytopenic purpura

Wegener's granulomatosis is a distinct form of necrotizing granulomatous vasculitis which usually affects the kidneys and the upper and lower respiratory tracts. Unusual manifestations have also been reported, and these include colitis, urethritis and diabetes insipidus. We describe a case of Wegener's granulomatosis which presented with rapidly progressive renal insufficiency, sudden deafness, red eye, facial palsy, and complicated by uncommon manifestations that were diffuse pulmonary hemorrhage and thrombotic thrombocytopenic purpura.

The National Institute on Aging/Alzheimer's Association recommendations on the application of apolipoprotein E genotyping to Alzheimer's disease

In a conference held in Chicago during October 1995, a working group of the National Institute of Aging (NIA) and the Alzheimer's Association (AlzA) drafted consensus recommendations on research and clinical applications of APOE genetic susceptibility testing for Alzheimer's disease (AD). The NIA/AlzA Working Group concluded that in considering future applications of APOE genotyping and other knowledge that has been gained about the genetic basis of AD, the interests of AD patients and their family members must be held paramount. The group acknowledged that a robust association exists between possession of the APOE epsilon 4 allele and the risk of late-onset AD and cited evidence that this allele is more strongly associated with AD than any other form of dementia. They recommended against the use of APOE genotyping to predict the-future development of AD in asymptomatic individuals at this time, and warned against the use of the test in isolation as the sole means for diagnosing AD. The group endorsed the concept of discretionary use of APOE genotyping as an adjunct to other AD diagnostic procedures. However, routine clinical use of the test for this purpose was not recommended at this time. Physicians were advised to weigh any potential benefits of testing against the possibility that genotype disclosure could adversely affect the insurability, employability, and social standing of AD patients and their family members. Adequate provisions for pre-test and post-test counseling and psychosocial support were advised for all future clinical and research applications of APOE genotyping. The group called for the development of improved protocols for AD genetic counseling as well as supplemental measures to assure genetic privacy for AD patients and their family members.

An outbreak of Heinz body positive hemolytic anemia in chronic hemodialysis patients

During the four month period, from December 1988 to March 1989, there was an outbreak of Heinz body positive hemolytic anemia in 34 patients undergoing hemodialysis in a 500-bed hospital, Seoul, Korea. The episodes of hemolysis were not reduced by changing the charcoal column and reverse osmosis system, or by adding ascorbic acid to the dialysate. The concentrations of nitrate, copper, aluminum and zinc in the treated water were all within the standards for hemodialysis. The chloramine concentration of the treated water was over 0.6 mg/L, markedly exceeding the allowable level of 0.1 mg/L. This high level of chloramine was proved to be due to the contamination of the water source by raw sewage. After we changed the source of water supply to another, no more episodes of hemolytic anemia occurred. It is concluded that chloramine is one of the major contaminants causing dialysis-induced hemolytic anemia and regular determinations are necessary, especially during winter and dry seasons.

Mycobacterium fortuitum peritonitis associated with continuous ambulatory peritoneal dialysis

Runyon group IV atypical mycobacteria, Mycobacterium fortuitum, is an environmental organism and is capable of producing a variety of clinical infections such as cutaneous infection, abscess and pulmonary and ocular infection. Rarely, it has been a documented cause of peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD). We report a case of M. fortuitum peritonitis in a patient undergoing CAPD and emphasize the importance of mycobacterial cultures in patients with CAPD-associated peritonitis whose routine culturing yields no organisms repeatedly.

Disturbances in autoregulatory responses of rat pial arteries by sulfonylureas

It was aimed to test the role of ATP-sensitive K+ channels in the autoregulatory response of cerebral arterioles in vivo. Changes in pial arterial caliber (mean, 43.2 +/- 2.3 microns in diameter) in response to changes in systemic arterial blood pressure (mean, 104.3 +/- 1.4 mmHg) were observed directly through closed cranial windows in anesthetized normotensive rats. During superfusion with vehicle, pial arterial caliber automatically increased in response to hypotension induced by arterial bleeding into a reservoir and decreased on reverse of arterial blood pressure by infusion of blood. After pretreatment with sulfonylureas, glibenclamide (1 and 3 microM) and glipizide (30 and 100 microM), arteriolar dilatation and constriction observed during hypotension and its reverse were disturbed. A similarity was evidenced when hypotension was induced by sodium nitroprusside (750 nmol kg-1min-1, i.v.). Cromakalim, a K+ channel opener, exerted a concentration-dependent vasodilatation of the pial artery and its effect was antagonized by glibenclamide. These data suggest that the endogenous glibenclamide-sensitive K+ channel opener is involved in the modulation of cerebral microvascular autoregulation.

Clinical review of 20 cases of Addison's disease in Korea--including previously reported cases and 6 new cases at the National Medical Center

Addison’s disease is a rare disorder resulting from a chronic deficiency of adrenol cortical hormone. The clinical manifestations and data of 20 patients with Addison’s disease were reviewed. They include 14 previously reported cases, total cases in korea upto 1987, and 6 new cases at National Medical Center. 13 patients were male and 7 female. The mean age was 39 years and ranged from 16 to 61 years. Common symptoms included mucocutaneous pigmentation (95 %), general weakness (90%), nasuea and/or vomiting (80%), and weight loss (60%). Initial mean blood pressure was 96±21/63±14 mmHg and adrenal crises were found in 5 cases (25%). Laboratory data indicated hyponatremia and hyperkalemia, resulting in a decreased Na/K ratio. Serum basal cortisol and ACTH levels were 2.86±1.93 ug/dl and 482.5/269.3 pg/ml, respectively. Extra-adrenal tuberculosis was present in 14 cases (70%) as a very high incidence. These 14 cases (70%) were presumed to be due to adrenal tuberculosis, although only two cases were confirmed as such by histopathology. The other cases were likely to be non-tuberculous.

Thus, tuberculosis may be-considered as a predominant cause of Addision’s disease in Korea. Other features were not unusual. But further detailed and extensive studies are necessary including more pathologically confirmed cases.