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Biomedical subjects

J Y Choi

Publications and source records attributed to J Y Choi.

At least 109 records · Page 6Linked to original sources
PubMed1999

Follow-up results of transvenous occlusion of patent ductus arteriosus with the buttoned device.

OBJECTIVES: The purpose of this presentation is to document results of buttoned device (BD) occlusion of patent ductus arteriosus (PDA) in a large number of patients with particular emphasis on long-term follow-up in an attempt to provide evidence for feasibility, safety and effectiveness of this method of PDA closure. BACKGROUND: Immediate and short-term results of BD occlusion of PDA have been documented in a limited number of children. METHODS: During a six-year period ending August 1996, transcatheter BD closure of PDA was attempted in 284 patients, ages 0.3 to 92 years (median 7) under a protocol approved by the local institutional review boards and FDA with an investigational device exemption in U.S. cases. RESULTS: The PDAs measured 1 to 15 mm (median 4) at the narrowest diameter; 20 were larger than 8 mm and 10 larger than 10 mm. They were occluded with devices measuring from 15 to 35 mm delivered via 7F (N = 140) or 8F (N = 144) sheaths. Successful implantation of the device was accomplished in 278 (98%) of 284 patients. The Qp:Qs decreased from 1.8+/-0.6 (mean+/-SD) to 1.09+/-0.19 (p < 0.001). Effective occlusion defined as no (N = 167 [60%]) or trivial (N = 79 [28%]) residual shunt was achieved in 246 (88%) patients. All types of PDAs, irrespective of the shape (conical, tubular or short), size (small or large) or length (short or long) of the PDA and previously implanted Rashkind devices, could be occluded. Follow-up data, 1 to 60 months (median 24) after device implantation, were available in 234 (84%) patients. Seven (3%) patients required reintervention to treat residual shunt with (N = 2) or without (N = 5) hemolysis. Actuarial reintervention-free rates were 95% at 1 and 5 years. There was gradual reduction of actuarial residual shunts and were 40%, 28%, 21%, 14%, 11%, 10%, 6% and 0% respectively at 1 day, 1, 6, 12, 24, 36, 48 and 60 months after device implantation. Incorporation of folding plug over the button loop in 10 additional patients produced immediate and complete occlusion of PDA. CONCLUSIONS: This large multiinstitutional experience confirms the feasibility, safety and effectiveness of buttoned device closure of PDAs. All types of PDAs irrespective of the shape, length and diameter can be effectively occluded. Incorporation of folding plug over the button loop produces complete PDA occlusion at the time of device implantation.

Adolescent↗
PubMed1999

Thermolabile 8-hydroxyguanine DNA glycosylase with low activity in senescence-accelerated mice due to a single-base mutation.

8-hydroxyguanine (8-oxoguanine; oh8Gua) DNA glycosylase (OGG1) repairs oh8Gua, a highly mutagenic oxidative DNA damage. In the present study, we compared two strains of senescence-accelerated mouse (SAM) expressing senescence-prone phenotypes, SAMP1 and SAMP8, with one strain of SAM expressing senescence-resistant phenotype, SAMR1. We found three distinct characteristics of OGG1 in SAMPs: (i) low activity (10-40% of the SAMRI enzyme in all organs and ages observed), (ii) thermolability, and (iii) mutation from Arg (CGG) in SAMR1 to Trp (TGG) at codon 304. There was no difference in the levels of mRNA and protein. As expected, oh8Gua level in tissues was higher in the SAMPs. In contrast, O6-methylguanine-DNA methyltransferase, which repairs alkylated DNA, showed no difference in its activity. The impairment of oh8Gua repair activity caused by the 304 mutation in OGG1 may be one of the factors contributing to the high somatic mutation rate and the accelerated senescence observed in these strains.

Aging↗
PubMed1999

Natural course of supravalvar aortic stenosis and peripheral pulmonary arterial stenosis in Williams' syndrome.

We investigated the catheterization and angiographic findings of 26 patients with Williams' syndrome to evaluate the natural course of supravalvar aortic stenosis and peripheral pulmonary arterial stenosis. The severity of the stenosis was correlated with age and body surface area in terms of the pulmonary arterial index, right ventricular systolic pressure, sinutubular ratio (ratio of measured to mean normal diameter of sinutubular junction), and systolic pressure gradient across the sinutubular junction. In patients with pulmonary arterial stenosis (n=20), right ventricular systolic pressure tended to decrease, and pulmonary arterial index increased, with increase in age and body surface area. Between the groups with and without pulmonary arterial stenosis, there was significant difference in age (mean 4.70 vs. 9.87, p=0.019), body surface area (0.62 vs. 1.16, p=0.002), pulmonary arterial index (152 vs. 317, p=0.002) and right ventricular systolic pressure (73.9 vs. 33.0, p=0.006). As all patients showed similar diameters at the sinutubular junction regardless of age and body size, sinutubular ratio decreased with increases in age and body surface area. The group with abnormal coronary arteries (n=7) had smaller sinutubular ratio (0.46 vs. 0.61, p=0.021) and higher pressure gradients between the left ventricle and the aorta (67.6 vs. 42.2, p=0.023) than did the group with normal coronary arteries. Stenosis of a coronary artery, or a branch of the aortic arch, was observed only in three patients with diffuse aortic stenosis. Our results suggest that, with time, peripheral pulmonary arterial stenosis tends to improve, and supravalvar aortic stenosis to progress. Failure of growth of the sinutubular junction might be responsible for the progression of the aortic lesion. Progression of the aortic lesion may be associated with involvement of the coronary arteries.

Adolescent↗
PubMed1999

Non-linear cardiac dynamics and morning dip: an unsound circadian rhythm.

The frequency of sudden cardiac death increases in the morning. The relationship between decreased complexity of heart rate dynamics and sudden cardiac death has been documented. An understanding of circadian variation in the complexity of cardiac dynamics may be important to predict and prevent sudden cardiac death. Dynamic 24-h electrocardiographic recordings were obtained from 30 healthy ambulant subjects aged 41-50 years, and the digitized data were partitioned into sections of 30 min duration. For each section, four indexes obtained from separate algorithms of non-linear dynamics of the RR interval--modified correlation dimension, Lyapunov exponent, approximate entropy, and fractal dimension--were calculated. Normalized low-(0.04-0.15 hertz) and high-frequency (> 0.15 hertz) components were also calculated. All four indexes of non-linear dynamics showed a remarkably similar circadian rhythm: a prominent morning dip preceded by a steep decline during the late night, a recovery during the evening and a peak around midnight. In the morning, the low-frequency component rose rapidly with concomitant reduction in the high-frequency component. The complexity of cardiac dynamics decreases significantly in the morning, and this may contribute to the ominously increased rate of cardiac death in the morning hours.

Adult↗
PubMed1999

Aging process is accompanied by increase of transglutaminase C.

Crosslinking has been suggested as one of the mechanisms involved in the aging process. Among the various random or enzyme-mediated crosslinking reactions, transglutaminase (TGase)-catalyzed crosslinking activity has been proposed for its possible involvement in cell proliferation, differentiation, carcinogenesis, programmed death, and aging. Moreover, recent findings of TGase C as a putative signal transducer and cell cycle regulator has renewed interest in the study of TGase C in relation to aging phenomena. The ubiquitous presence of TGase C compared to the organ-specific localization of other types of TGases has attracted special attention as a cellular aging device. In the present investigation for in vitro studies, we have compared the pattern of TGase C in young and old human red blood cells, separated by density differentiation, and in early and late-passage or hydrogen peroxide-treated human primary fibroblasts. For in vivo study, we monitored the age-dependent changes of TGase C in the liver and brain tissues of 4, 12, 18, and 24-month-old Sprague-Dawley rats. We obtained evidence that both the activity and protein levels of TGase C were high in old RBC and late-passage or hydrogen peroxide-treated fibroblasts. Similar findings were seen in liver and brain tissue such as age-dependent increases in TGase activity and protein level in an organ-specific pattern. These data suggest that TGase C might play an active role in the cellular process with age.

Adult↗
PubMed1999

Atypical pulmonary artery sling with diffuse-type pulmonary arteriovenous fistula.

The case of a cyanotic infant with a rare combination of atypical pulmonary artery sling, imperforate anus, absence of the left kidney, interruption of the inferior vena cava, left side hemihypertrophy and diffuse-type pulmonary arteriovenous fistula is described. The clinical features were confusing, because of compounding abnormalities involving the respiratory tract and pulmonary circulation. The diagnostic approach to the etiology of cyanosis is discussed and the embryonic origin of pulmonary artery sling is reviewed.

Arteriovenous Fistula↗
PubMed1999

Two cases of common bile duct stone after liver transplantation.

Biliary complications after orthotopic liver transplants are a continuing cause of morbidity and mortality. Biliary stones and sludge are less well known complications of hepatic transplantation, although they have long been recognized. Recently we experienced two cases of biliary stones developed after liver transplantation. One 32-year-old male, who frequently admitted due to recurrent cholangitis, was treated with percutaneous transhepatic biliary drainage and choledochojejunostomy with cholecystectomy. The other 58-year-old male, who had stones in commone bile duct, was treated by endoscopic manipulation. They are in good condition without recurrent bile duct stones or its accompanying complications. Although stones and sludge are relatively infrequent after liver transplantation, surgical or interventional radiologic treatments are usually performed for treatment.

Adult↗
PubMed1999

Monitoring antibody titers to recombinant Core-NS3 fusion polypeptide is useful for evaluating hepatitis C virus infection and responses to interferon-alpha therapy.

To evaluate the clinical feasibility of the antibody titer against a chimeric polypeptide (named Core 518), in which a domain of Core and NS3 of hepatitis C virus (HCV) was fused, ELISA was performed in a total of 76 serum samples. Each serum was serially diluted using two-fold dilution method with distilled water into 10 concentrations. They were all positive for second generation anti-HCV assay (HCV EIA II; Abbott Laboratories). Genotyping RT-PCR, quantitative competitive RT-PCR, and RIBA (Lucky Confirm; LG Biotech) were also assayed. Anti-Core 518 antibody was detected in x 12800 or higher dilutions of sera from 35 of 43 chronic hepatitis C (81.4%) and nine of 16 hepatocellular carcinoma sera (56.3%), one of four cirrhosis (25%), 0 of four acute hepatitis C, and one of nine healthy isolated anti-HCV-positive subjects (p=0.0000). The anti-Core 518 antibody titers were well correlated with the presence of HCV RNA in serum (p=0.002). The anti-Core 518 antibody titers decreased significantly in nine of ten responders to IFN-alpha treatment. Monitoring anti-Core 518 titers may be helpful not only for differentiating the status of HCV infection among patients with various type C viral liver diseases, but also for predicting responses to IFN-alpha treatment.

Adult↗
PubMed1999

Adenovirus-mediated p53 tumor suppressor gene therapy against subcutaneous HuH7 hepatoma cell line nodule of nude mice.

Mutations of the tumor-suppressor gene p53 have been found in 30-50% cases of hepatocellular carcinoma (HCC). In this study, E1-negative adenoviral vector encoding wild-type p53 under the control of the human cytomegalovirus promoter (AdCMV-p53w) was constructed to evaluate its therapeutic efficacy against tumor nodules developing after injection of HuH7 cell lines in ten nude mice. When each nodule had reached 10 mm in perpendicular diameter, 1.5 x 10(8) pfu of AdCMV-p53w per session was injected intratumorally as follows: In group I (n=3), five sessions were injected every other day. In group II (n=3), only one session. Group III (n=4) as negative controls. The mice were sacrificed at 28 days post AdCMV-p53w injection. Tumor growth was significantly suppressed and delayed in group I and II compared to group III as compared by tumor volume at the end of observation. These results suggest that AdCMV-p53w may not only be effective in treating HCCs expressing mutant p53, but also useful as a local injectable gene therapy.

Adenoviruses, Human↗
PubMed1999

Pulmonary hypertension in a child with juvenile-type autosomal recessive polycystic kidney disease.

An 11 year-old girl, whose condition was diagnosed as juvenile-type autosomal recessive polycystic kidney disease (ARPKD) at five years of age, presented with chest pain and dyspnea that had developed suddenly two months previously. Two-dimensional echocardiography, Doppler study and cardiac catheterization confirmed pulmonary hypertension. The underlying mechanism of the diagnosis was not defined. Two and a half months after the onset of symptoms, the patient died of pulmonary hypertensive crisis. Careful regular checks of cardiopulmonary status using two-dimensional echocardiography and Doppler should be considered for the early detection of pulmonary hypertension even in an asymptomatic patient with juvenile-type ARPKD.

Biopsy↗
PubMed1999

Noise level of drilling instruments during mastoidectomy.

Exposure to intense noise has been identified as a potential risk in the development of hearing impairment. Social concern about excessive noise is increasing and this also extends to the operating room. A noise level study was performed in the operating room during mastoidectomy with a sound level meter and it was analyzed by a sound-analyzing program. The drilling instruments used included the Stryker, Midas, M.P.S. and Med-Next. The operator was exposed to sound levels from 69 to 83 dBA. The loudest drilling instrument was the Midas and it produced an average sound level of 83 dBA to the operator. The mean exposure time was 41 minutes during mastoidectomy. This is below the occupational noise-level regulations in Korea. However, considering that individual susceptibility to noise varies and that the otologic surgeon is repeatedly exposed to prolonged drilling noise, ear protection is recommended for the operators of high-speed drilling instruments.

Chronic Disease↗
PubMed1999

Changes in lymphatic function after complex physical therapy for lymphedema.

Twenty-two extremities of 19 lymphedema patients (6 arms, 16 legs) were treated by 2 weeks of complex physical therapy (CPT) and self home maintenance therapy (bandage/wearing of elastic garment and exercise). In addition to the clinical response of volume reduction before and 3 months after CPT, we analyzed the functional changes of the peripheral lymphatic system by use of lymphoscintigraphy (LS). Before CPT, the main LS findings of lymphedema included dermal backflow (100%), absent or faintly visualized regional lymph nodes (95.5%), presence of collateral lymphatic vessels (68.2%), and no or barely visualized lymphatic vessels (27.3%). LS findings suggesting improved lymphatic function after CPT were a decrease in dermal backflow (72.7%), an increase in radioisotope uptake by lymphatic vessels (27.3%), and an increase in radioisotope uptake by lymph nodes (9.1%). 81.8% of limbs showed improved lymphoscintigraphic findings and no change in 9.1%. In the others (9.1%), LS findings appeared worse. There was, however, no correlation between LS "improvement" and the amount of limb volume reduction.

Antimony↗
PubMed1998

Molecular cloning and analysis of transcription initiation in the Anagrapha falcifera multiple nucleocapsid polyhedrosis virus polyhedrin gene.

Using Autographa californica multiple nucleocapsid polyhedrosis virus (AcMNPV) polyhedrin to probe the Southern blots of Anagrapha falcifera multiple nucleocapsid polyedrosis virus (AfMNPV), we identified the location of the AfMNPV polyhedrin gene within the 7.2 kb EcoRI fragment. The 7.2 kb EcoRI fragment of AfMNPV was cloned and the nucleotide sequences of the polyhedrin coding region and its flanking regions were determined. Nucleotide sequence analysis indicated the presence of an open reading frame (ORF) of 735 nucleotides (nt) which could encode 245 amino acids with a predicted molecular mass of 29 kDa. The nucleotide sequences within the coding region of the AfMNPV polyhedrin shared 80% similarity with the polyhedrin gene from AcMNPV but were most closely related to Bombyx mori NPV with 92% sequence identity. The size of the AfMNPV polyhedrin mRNA, determined by the Northern blot analysis, was estimated to be 1200 nt. The consensus promoter sequence (ATAAG) for the baculovirus very late gene was also observed. Two degenerate poly(A) tailing signals were found immediately downstream of the translational stop codon. The transcription initiation site, mapped by primer extension analysis, was found to be at T located 24 nt upstream from the A of the translation initiation codon. This site is located 26 nt downstream from the second A of the consensus TAAG, the transcription initiation site of most other NPVs.

Amino Acid Sequence↗
PubMed1998

Molecular cloning of a novel GTP-binding protein induced in fish cells by rhabdovirus infection.

We have cloned and sequenced a cDNA encoding GTP-binding protein from a fish cell, CHSE-214. The clone was 1493 bp long and contained an open reading frame encoding 364 amino acids. It has the five sequence motifs G1-G5 that are conserved in all GTP-binding proteins. Its amino acid sequences are strikingly different from those of the well-characterized G-proteins. However, sequences closely related to this protein are found in various kinds of species including human, Arabidopsis, Drosophila and archaebacteria, suggesting a novel subfamily within the superfamily of the GTP-binding proteins. Northern analysis indicates that this gene is constitutively expressed at a low level in normal cells but is induced by fish rhabdovirus infection at about 24 h post infection and disappears thereafter. Based on these observations, we propose that this protein represents an evolutionarily conserved novel subfamily of GTP-binding proteins which may play an important role in fish rhabdovirus infection.

Amino Acid Sequence↗
PubMed1998

Telomerase is strongly activated in hepatocellular carcinoma but not in chronic hepatitis and cirrhosis.

Telomerase is highly activated in human immortal cell lines and tumor tissues, whereas it is not activated in primary cell strains and many tumor-adjacent tissues. It is suggested that telomerase activation is one of the critical steps in malignant transformation. In the present study, the telomerase activity was investigated in hepatocellular carcinoma tissues and non-tumor liver tissues from Korean patients with chronic hepatitis and cirrhosis. Eighty two liver tissues (24 chronic hepatitis specimens, 34 cirrhosis specimens, and 24 hepatocellular carcinomas) were obtained from 23 chronic viral hepatitis patients, 19 cirrhosis patients (including 7 liver transplants), and 24 patients with hepatocellular carcinoma, of which the surrounding non-tumor liver tissues were available in 16 patients (1 chronic hepatitis and 15 cirrhosis). As negative controls, 3 normal liver tissues were included. Protein from liver specimens was purified by a detergent lysis method as described elsewhere, and telomerase activity was measured in 2 diluents of each sample (1:1 and 1:100) by a telomeric repeat amplification protocol (TRAP). Telomerase was strongly activated in 79% (19/24) of the hepatocellular carcinomas, while weakly in 8% (2/24) of the chronic hepatitis tissues and in 24% (8/34) of the cirrhosis tissues. All of 3 normal control livers showed no telomerase activation. No relationship could be observed between the enhancement of telomerase activity and tumor nature. None of the chronic heaptitis or cirrhosis patients with mild telomerase activation in the liver have developed hepatocellular carcinoma for at least 2 years of follow-up period. These results suggest that the strong enhancement of telomerase activity may be a critical part of hepatocarcinogenesis, although the exact mechanism of such high activation in hepatocellular carcinoma is not clear. In addition, further study will be necessary to clarify the reason why no telomerase activity detectable by a conventional TRAP can be seen in some hepatocellular carcinoma.

Adult↗
PubMed1998

Cloning of the 52-kDa chitinase gene from Serratia marcescens KCTC2172 and its proteolytic cleavage into an active 35-kDa enzyme.

A chitinase gene (pCHI52) encoding the 52-kDa chitinase was isolated from a Serratia marcescens KCTC2172 cosmid library. This chitinase gene consists of 2526 bp with an open reading frame that encodes 485 amino acids. Escherichia coli harboring the pCHI52 gene secreted not only a 52-kDa but also a 35-kDa chitinase into the culture supernatant. We purified both 52-kDa and 35-kDa chitinases using a chitin affinity column and Sephacryl-S-300 gel filtration chromatography. We determined that the 17 N-terminal amino acid sequences of the 52-kDa and the 35-kDa chitinase are identical. Furthermore, a protease obtained from S. marcescens KCTC2172 cleaved the 52-kDa chitinase into the 35-kDa protein with chitinase activity. These results suggest that the 35-kDa chitinase derives from the 52-kDa chitinase by post-translational proteolytic modification. The optimal reaction temperature of 45 degrees C and the optimal pH of 5.5 were identical for both enzymes. The specific activities of the 52-kDa and 35-kDa chitinases on natural swollen chitin were 67 mumol min-1 mg-1 and 60 mumol min-1 mg-1, respectively.

Amino Acid Sequence↗