PubMed Health⌕ Search

Biomedical subjects

H Shin

Publications and source records attributed to H Shin.

At least 19 recordsLinked to original sources
PubMed2006

The genome of black cottonwood, Populus trichocarpa (Torr. & Gray).

We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.

Arabidopsis↗
PubMed2004

[CT-based liver volumetry in a porcine model: impact on clinical volumetry prior to living donated liver transplantation].

PURPOSE: Exact preoperative determination of the liver volume is of great importance prior to hepatobiliary surgery, especially in living donated liver transplantation (LDLT). In the current literature, a strong correlation between preoperatively calculated and intraoperatively measured liver volumes has been described. Such accuracy seems questionable, primarily due to a difference in the perfusion state of the liver in situ versus after explantation. Purpose of the study was to asses the influence of the perfusion state on liver volume and the validity of the preoperative liver volumetry prior to LDLT. METHODS: In an experimental study, 20 porcine livers were examined. The livers were weighted and their volumes were determined by water displacement prior and after fluid infusion to achieve a pressure physiologically found in the liver veins. The liver volumes in the different perfusion states were calculated based on CT-data. The calculated values were compared with the volume measured by water displacement and the weight of the livers. RESULTS: Assessment of calculated CT volumes and water displacements at identical perfusion states showed a tight correlation and differed on average by 4 +/- 5 %. However, livers before and after fluid infusion showed a 33 +/- 8 % (350 +/- 150 ml) difference in volume. CONCLUSION: CT-volumetry acquires highly accurate data as confirmed by water displacement studies. However, the perfusion state has major impact on liver volume, which has to be accounted for in clinical use.

Animals↗
PubMed2003

Performance and membrane fouling in a pilot scale SBR process coupled with membrane.

The performance of the pilot-scale submerged membrane coupled with sequencing batch reactor (SM-SBR) for upgrading effluent quality was investigated in this study. The reactor was operated with 3-hour cycle with alternating anoxic and aerobic conditions to treat organics, nitrogen and phosphate. Despite various influent characteristics, COD removal was always higher than 95%. Sufficient nitrification was obtained within a few weeks after start-up and during the stable period, complete nitrification occurred despite short aeration time. Total nitrogen (TN) removal efficiency was reached up to 85%. Membrane flux was critical for TN removal so that the decrease of flux by membrane fouling led to increase of HRT, and it caused the endogenous respiration of microorganisms such as nitrifying bacteria. The stirred cell test revealed the significant role of the soluble fraction in membrane permeability and dissolved solids played a major role in the short-term fouling mechanism. The cake resistance by the soluble COD fraction of supernatant or soluble microbial products (SMP) was investigated as a major part of total resistance.

Bacteria↗
PubMed2003

Inhibitory effects of long-chain fatty acids on VFA degradation and beta-oxidation.

The inhibitory effects of major long-chain fatty acids (LCFA), which have 16 or 18 carbons, not only on acetate degradation, but also on propionate degradation and beta-oxidation were examined in anaerobic serum bottle tests at 35 degrees C with the acclimated granular sludges. A modified Gompertz equation described cumulative methane production to assess the rates of VFA degradation and beta-oxidation, which were applied to a simplified noncompetitive model and a simplified substrate inhibition model, respectively. The specific methane production rates on acetate decreased as LCFA concentration increased, which was in good agreement with the noncompetitive inhibition model. Unsaturated oleate (C18:1) and linoleate (C18:2) were more inhibitory than saturated stearate (C18:0) and palmitate (C16:0) on acetate degradation. LCFA inhibition on propionate degradation was similar to that for acetate; however, propionate degradation was less inhibited than acetate degradation. Beta-oxidation was the rate-limiting step in LCFA degradation in most cases. As LCFA concentration increased, beta-oxidation rate reached the maximum value, and then decreased, which confirmed the substrate inhibition of LCFA. Oleate, the most abundant LCFA in wastewater, could be degraded more quickly than saturated LCFA containing the same or even less carbon in spite of relatively high toxicity on acetate degradation.

Acetates↗
PubMed2002

Neurotrophin potentiation of iron-induced spinal cord injury.

Previous studies have shown that pretreatment with neurotrophins can potentiate the vulnerability of cultured neurons to excitotoxic and free radical-induced necrosis, in contrast to their well known neuroprotective effects against apoptosis. Here we tested the hypothesis that this unexpected injury-potentiating effect of neurotrophins would also take place in the adult rat spinal cord. Fe(3+)-citrate was injected stereotaxically into spinal cord gray matter in adult rats in amounts sufficient to produce minimal tissue injury 24 h later. Twenty-four-hour pretreatment with brain-derived neurotrophic factor, neurotrophin-3, or neurotrophin-4/5, but not nerve growth factor, markedly enhanced tissue injury in the gray matter as evidenced by an increase in the damaged area, as well as the loss of neurons and oligodendrocytes. Consistent with maintained free radical mediation, the neurotrophin-potentiated iron-induced spinal cord damage was blocked by co-application of the antioxidant N-tert-butyl-(2-sulfophenyl)-nitrone. These data support the hypothesis that the overall neuroprotective properties of neurotrophins in models of acute injury to the spinal cord may be limited by an underlying potentiation of free radical-mediated necrosis.

Animals↗
PubMed2002

[Interactive direct volume rendering of CT-data: technical principle and applications].

The advantages of interactive Volume Rendering Technique (VRT) for routine diagnostics of CT and particularly Multislice CT data are unquestionable. However, with apart from Virtual Endoscopy, where besides Shaded Surface Display, perspective Volume Rendering is used in some cases, VRT at present is only playing a minor role in routine diagnostics. One reason is time consuming calculation, so far requiring powerful computers. Due to the variety of possible parameter settings and the poorly predictable outcome of the resulting images, there also exists a certain discomfort in using the technique. In this paper the underlying principles of VRT are illustrated. Different parameter settings and their impact on the final images are explained. Possible pitfalls in VRT and also suitable parameter settings and indications for VRT are shown.

Angiography↗
PubMed2002

Interactive PC-based volume rendering of CT datasets.

In radiology, the reading of large CT volumes is a time consuming task. Interactive volume rendering (iVRT) is a promising new technique. Using dedicated hardware (VP1000, Terarecon Inc.) it can now be realized on a standard PC in a cost effective manner. For this purpose, a program built using the Visualization Toolkit with integrated functionality for the VP 1000 is used for almost real-time iVRT (8-9 frames/second). It is possible to embed opaque and translucent polygon surfaces (e.g., segmented structures). By interactively varying the opacity, color and gradient transfer functions as well as using freely placable cutting planes, the visualization can easily be adapted to different diagnostic needs.

Humans↗
PubMed2001

Human kinesin superfamily member 4 is dominantly localized in the nuclear matrix and is associated with chromosomes during mitosis.

In a previous study, we identified the human counterpart of murine kinesin superfamily member 4 (KIF4), a microtubule-based motor protein [Oh, Hahn, Torrey, Shin, Choi, Lee, Morse and Kim (2000) Biochim. Biophys. Acta 1493, 219-224]. As an initial step to understand the function(s) of human KIF4, its subcellular localization in HeLa cells was examined by using immunocytochemical and subcellular fractionation methods, and it was found that most KIF4 is localized in the nucleus. Since murine KIF4 is known to transport cytoplasmic vesicles, dominant nuclear localization of the human counterpart was somewhat surprising. Subsequent subnuclear fractionation revealed predominant association of KIF4 with the nuclear matrix. These results clearly indicate that human KIF4 is, at least, a nuclear protein. In further confirmation of this conclusion, the hexapeptide PKLRRR (amino acids 773-778) in the molecule was found to function as a nuclear localization signal. During the mitotic phase of the cell cycle, human KIF4 was associated with the chromosomes, suggesting that human KIF4 might be a microtubule-based mitotic motor, with DNA as its cargo.

Adenocarcinoma↗
PubMed2001

The dependence receptor DCC (deleted in colorectal cancer) defines an alternative mechanism for caspase activation.

The expression of DCC (deleted in colorectal cancer) is often markedly reduced in colorectal and other cancers. However, the rarity of point mutations identified in DCC coding sequences and the lack of a tumor predisposition phenotype in DCC hemizygous mice have raised questions about its role as a tumor suppressor. DCC also mediates axon guidance and functions as a dependence receptor; such receptors create cellular states of dependence on their respective ligands by inducing apoptosis when unoccupied by ligand. We now show that DCC drives cell death independently of both the mitochondria-dependent pathway and the death receptor/caspase-8 pathway. Moreover, we demonstrate that DCC interacts with both caspase-3 and caspase-9 and drives the activation of caspase-3 through caspase-9 without a requirement for cytochrome c or Apaf-1. Hence, DCC defines an additional pathway for the apoptosome-independent caspase activation.

Apoptosis↗
PubMed2001

Pattern recognition for road traffic accident severity in Korea.

An increasing number of road traffic accidents (RTA) in Korea has emerged as being harmful both for the economy and for safety. An accurately estimated classification model for several severity types of RTA as a function of related factors provides crucial information for the prevention of potential accidents. Here, three data-mining techniques (neural network, logistic regression, decision tree) are used to select a set of influential factors and to build up classification models for accident severity. The three approaches are then compared in terms of classification accuracy. The finding is that accuracy does not differ significantly for each model and that the protective device is the most important factor in the accident severity variation.

Accidents, Traffic↗
PubMed2001

Optimal positioning of temporary epicardial atrial pacing leads after cardiac surgery.

OBJECTIVES: Atrial pacing plays an important role in preventing low output syndrome and arrhythmia after cardiac surgery. We studied the optimal positioning for temporary epicardiac atrial pacing. METHODS: The performance of temporary epicardiac atrial pacing leads was examined after 13 cases of elective coronary artery bypass grafting between October 1999 and January 2000. Two bipolar electrode leads were used--1 on the cephalic atrial wall between the left and right atrial appendages, where the Bachmann bundle indwells (site A), and the other on the interatrial groove (site B). To assess pacing performance on postoperative days 1, 2, and 7, we measured 3 pacing patterns--bipolar use of sites A and B leads, and combined use of the 2 with the site A lead acting as the negative electrode and the site B lead as the ground. The pacing threshold was measured at a 0.5 ms pulse width, using the P wave amplitude and slew rate as indicators of sensing performance. RESULTS: Bipolar pacing both at sites A and A-B was superior to that at site B in pacing threshold and sensing parameters. CONCLUSIONS: The negative electrode at site A is mandatory for high atrial pacing and sensing performance.

Cardiac Pacing, Artificial↗
PubMed2001

Port-access cardiac surgery. Experience with 34 cases at Keio University Hospital.

OBJECTIVES: We reviewed our experience with port-access cardiac surgery and evaluated the medical effects and benefits of this technique in view of postoperative quality of life and medical expenses incurred during hospitalization. METHODS: From June 1998 to August 2000, port-access cardiac surgery was conducted on 34 patients--22 with atrial septal defect, 6 with mitral regurgitation, 2 with coronary artery disease, 2 with partial endocardial cushion defect, 1 with ventricular septal defect, and 1 with atrial and ventricular septal defects. Two types of endoaortic-balloon catheters were used to execute aortic cross-clamping. Skin incisions were 5 cm long. RESULTS: No hospital or late deaths were observed. Patients with atrial septal defect were discharged on postoperative day 3.7, patients of mitral regurgitation on postoperative day 4.2, and patient of ventricular septal defect on postoperative day 4.0 on the average. None were readmitted. Patients appeared undisturbed by early discharge and were able to resume physical work on day 22 on the average after discharge. CONCLUSION: Patients undergoing port-access cardiac surgery recovered quickly from surgery and resumed work quickly. This technique thus proved satisfactory both physically and mentally to patients and improved their quality of life. Medically and economically this technique proved extremely beneficial. We confirmed it to constitute a viable approach and option for cardiac surgery in selected patients.

Adolescent↗
PubMed2001

Detection and management of concomitant coronary artery disease in patients undergoing thoracic aortic surgery.

OBJECTIVES: No method has been established to detect and manage coronary artery disease in patients undergoing thoracic aortic surgery. METHODS: Subjects were 192 patients scheduled for elective thoracic aortic surgery. Selection criteria for coronary angiography included a history of coronary artery disease or a positive dipyridamole myocardial perfusion imaging test. RESULTS: Four patients were inoperable due to complications associated with coronary angiography or aneurysm rupture following coronary revascularization. A total of 55 patients with coronary angiography (group A) underwent 57 thoracic aortic operations and 133 patients without coronary angiography (group B) underwent 143 similar operations. Of 13 group A patients with significant coronary stenosis, 9 underwent either preoperative percutaneous transluminal coronary angioplasty (n = 3) or concomitant coronary artery bypass (n = 6). Perioperative myocardial infarction occurred in 3 group A patients (5%) and in 4 group B patients (1%, ns). The incidence of cardiac events--perioperative myocardial infarction or cardiac death--in group A (11%, 6/57) was higher than that in group B (3%, 4/143; p < 0.05). Multivariate analysis demonstrated incomplete revascularization of major coronary arteries with significant stenosis as a risk factor for cardiac events (p = 0.0106). CONCLUSIONS: Although dipyridamole myocardial perfusion imaging was useful, additional selection criteria for coronary angiography is needed. Complete revascularization of major coronary arteries with significant stenosis is essential to reduce postoperative cardiac events.

Adolescent↗
PubMed2001

Precise determination of aortic length in patients with aortic stent grafts: in vivo evaluation of a thinning algorithm applied to CT angiography data.

The aim of this study was to develop a technique for precise determination of the aortic length using volumetric CT data for potential use prior to endovascular stent-graft placement. The study population consisted of 20 patients (38 measurements) with already performed endoluminal grafting. This allowed for in vivo evaluation of our technique. Its length according to the graft specifications served as a gold standard for our own measurements. The implemented graft length varied between 120 and 195 mm. Computed tomography angiography was performed with 3-mm slice collimation, 5-mm table feed and a reconstruction interval of 2 mm. Following semi-automatic segmentation of the aorta and its large side branches, the median centerline (skeleton) of the vessels was determined employing a modified three-dimensional thinning algorithm. The algorithm was validated by comparing the calculated length of the resulting skeleton with the specifications of the grafts. The calculated length was sufficiently precise despite the limiting reconstruction interval of 2 mm of our CT data which only permitted an assessment of stent length in 2-mm steps. The differences in the measured length and graft length were in the range between 0 and 8 mm (< 5%) with a mean fractional error of 2.46 +/- 2.37 mm. The use of an intelligent region growing algorithm capable of coping with variable arterial enhancement significantly reduced operator post-processing time. The average time necessary for segmentation was 7 min (range 3-10 min). Our algorithm provides a non-invasive method for objective and precise measurement of aortic length apparently even in tortuous vessels. It has the potential to replace angiography for aortic and iliac length measurements with calibrated catheters prior to endovascular intervention.

Algorithms↗
PubMed2001

A putative plant homolog of the yeast beta-1,3-glucan synthase subunit FKS1 from cotton (Gossypium hirsutum L.) fibers.

A novel plant gene CFL1 was cloned from cotton (Gossypium hirsutum L.) fibers by expressed sequence tag (EST) database searching and 5'-RACE (rapid amplification of cDNA ends). This gene shows sequence homology with FKS1 which has been identified as the putative catalytic subunit of the yeast beta-1,3-glucan synthase. It encodes a protein (CFL1p) of 219 kDa with 13 deduced transmembrane helices and 2 large hydrophilic domains, one of which is at the N-terminus and the other in the internal region of the polypeptide. CFL1 displays 21% identity and 41% similarity to FKS1 at the amino acid level over its entire length, with 31% identity and 52% similarity for the hydrophilic central domain. Using RNA and protein blot analysis, CFL1 was found to be expressed at higher levels in cotton fibers during primary wall development. CFL1 also had a strong expression in young roots. Using a calmodulin (CaM)-gel overlay assay, the hydrophilic N-terminal domain of CFL1p was shown to bind to CaM, while the hydrophilic central domain did not. A putative CaM-binding domain, 16 amino acids long, was predicted in the hydrophilic N-terminal domain. Moreover, a product-entrapment assay demonstrated that a protein associated with an in vitro-synthesized callose pellet could be labeled by anti-CFL1 antibodies. Our finding suggests that CFL1 is a putative plant homolog of the yeast beta-1,3-glucan synthase subunit FKS1 and could be involved in callose synthesis.

Calmodulin-Binding Proteins↗
PubMed2001

Sinus node function after mitral valve surgery using the superior septal approach.

UNLABELLED: BACKGROUND; Sinus node function after the superior septal approach (SSA) in mitral valve surgery is controversial. We assessed sinus node function after this approach based on electrophysiological examinations and electrocardiographic change. METHODS: Forty-six patients underwent successful mitral valve surgery via the SSA. Preoperatively, 25 patients were in atrial fibrillation (AF), 20 were in normal sinus rhythm (SR), and 1 patient was paced. Thirteen patients who demonstrated no sinus node dysfunction preoperatively underwent postoperative electrophysiological studies. Peripostoperative cardiac rhythm was monitored using a portable four-lead electrocardiograph, and late cardiac rhythm was examined using standard 12-lead electrocardiography in the outpatient clinic. RESULTS: Twelve of 20 patients with preoperative SR experienced early postoperative supraventricular arrhythmias, but all spontaneously recovered SR. Electrophysiological studies revealed a basic cycle length of 767 +/- 74 ms, sinoatrial conduction time of 72 +/- 34 ms, sinus node recovery time of 1,119 +/- 139 ms, and corrected sinus node recovery time of 349 +/- 114 ms, thus demonstrating a lack of sinus node dysfunction. During the postoperative period (34 +/- 24 months), 2 of the 20 patients with preoperative SR developed persistent AF, and 3 of the 25 patients with preoperative AF achieved normal SR. CONCLUSIONS: The SSA does not appear to cause longterm adverse effects on sinus node function, although temporary effects may occur.

Adult↗
PubMed2001

Intraoperative assessment of coronary artery bypass graft: transit-time flowmetry versus angiography.

BACKGROUND: Transit-time flowmetry has been used to assess graft status intraoperatively. This study examines the validity of this method by comparing its results with the findings of simultaneously performed graft angiography. METHODS: The left internal thoracic artery (LITA) anastomosed to the left anterior descending artery (LAD) was assessed intraoperatively with both transit-time flowmetry and graft angiography in 30 patients. The patients were stratified into two groups based on intraoperative angiographic findings. In 18 patients (group A), the LITA and the LAD were well filled with contrast medium and the anastomosis was widely patent. In the other 12 patients (group B), spastic LITA or LAD was observed. Postoperative angiography was also performed before discharge from the hospital. RESULTS: The mean graft flow was 44.0 +/- 25.4 mL/min in group A and 23.4 +/- 10.0 mL/min in group B (p = 0.0129). Diastolic-dominant flow pattern was observed in both groups, and the ratio of peak diastolic flow to peak systolic flow and the percent diastolic time-flow integral were not statistically different between the groups. The pulsatility index was almost the same between the two groups and was acceptable in both. Postoperative angiography revealed that all grafts were patent without spasm or anastomotic stenosis. CONCLUSIONS: LITA graft status is satisfactory when high graft flow with diastolic dominance is obtained. When there is vasospasm but no anastomotic problems, decreased graft flow with an acceptable pulsatility index and diastolic augmentation is observed.

Angiography↗