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Biomedical subjects

S H Bae

Publications and source records attributed to S H Bae.

At least 37 records · Page 2Linked to original sources
PubMed2000

One-year follow-up of Graves' disease treatment by four different protocols of radioiodine administration.

BACKGROUND: Studies have been performed in order to assess a treatment with 131I able to induce a consistent improvement in Graves' hyperthyroidism. METHODS EXPERIMENTAL DESIGN: For this purpose, four different protocols based on four different doses of radioiodine have been tested in Graves' disease patients. Patients never submitted previously to antithyroid drug treatment were given 1 mCi/10 gm of the estimated thyroid weight (group I; n = 50). Group II (n = 48) included patients not previously treated with antithyroid drugs and who were given doses of iodine based on a formula taking into account the rate of thyroid iodine uptake, i.e. 131I dose = microCi/gm of the estimated thyroid weight x 100/24 hrs 131I uptake (%). Patients previously submitted to antithyroid drug therapy were treated with radioiodine whose dose was calculated according to the formula reported above, but the dose was increased in order to overcome the possible resistance of this kind of patients to the effect of 131I. One group (group III; n = 24) received the calculated dose plus 1 microCi/gm of the estimated thyroid weight. Finally, group IV (n = 27) received the calculated dose plus 0.25 microCi/gm of the estimated thyroid weight. RESULTS: The analysis of the patients one year later demonstrated that groups I and II presented the higher percent of euthyroid patients (60% and 58%, respectively) followed by group IV (37%) and group III (29.2%). The percent of patients still exhibiting hyperthyroidism was 28% in group I, 26% in group IV, 12.5% in group III and 8.3% in group II. The highest number of hypothyroid patients was present in group III (58.3%) followed by group IV (37%), group II (33.3%) and group I (12%). CONCLUSIONS: The data here presented suggest that protocols I and II based on relatively low doses of radioiodine are rather effective in reducing Graves' hyperthyroidism in patients not submitted previously to antithyroid drug therapy. The most satisfactory therapy seems that utilized in protocol II, that in front of a fair amount of euthyroid patients (58.3%) presents a very low number of subjects still hyperthyroid (8.3%). However, the number of patients who became hypothyroid (33.3%) as a consequence of the therapy was too high. Hopefully, a better design of the protocol will reduce this figure. The high incidence of hyperthyroidism observed in groups III and IV submitted to a therapy with 131I doses consistently higher than those utilized in groups I and II seems to confirm the hypothesis that hyperthyroid subjects submitted to a therapy with antithyroid drugs become rather resistant to a radioiodine treatment.

Adolescent↗
PubMed1999

Cholesterol biosynthesis from lanosterol. Molecular cloning, tissue distribution, expression, chromosomal localization, and regulation of rat 7-dehydrocholesterol reductase, a Smith-Lemli-Opitz syndrome-related protein.

The cDNA encoding the 471-amino acid rat 7-dehydrocholesterol reductase (DHCR), an enzyme that has been implicated in both cholesterol biosynthesis and developmental abnormalities (e.g. Smith-Lemli-Opitz syndrome) in mammals, has been cloned and sequenced, and the primary structure of the enzyme has been deduced. The DHCR gene was mapped to chromosome 8q2.1 by fluorescence in situ hybridization. Rat DHCR, calculated molecular mass of 54.15-kDa polypeptide, shares a close amino acid identity with mouse and human DHCRs (96 and 87%, respectively) as compared with its other related proteins (e.g. fungal sterol Delta14-reductase) and exhibits high hydrophobicity (>68%) with 9 transmembrane domains. Five putative sterol-sensing domains were predicted to be localized in transmembrane domains 4-8, which are highly homologous to those found in 3-hydroxymethylglutaryl-CoA reductase, sterol regulatory element-binding protein cleavage-activating protein, and patched protein. The polypeptide encoded by DHCR cDNA was expressed in yeast as a 55.45-kDa myc-tagged fusion protein, which was recognized with anti-myc monoclonal antibody 9E10 and shown to possess full DHCR activity with respect to dependence on NADPH and sensitivity to DHCR inhibitors. Northern blot analysis indicates that the highest expression of DHCR mRNA was detected in liver, followed by kidney and brain. In rat brains, the highest level of mRNA encoding DHCR was detected in the midbrain, followed by the spinal cord and medulla. Feeding rats 5% cholestyramine plus 0.1% lovastatin in chow resulted in both approximately a 3-fold induction of DHCR mRNA and a 5-fold increase of the enzymic activity in the liver. When rats were fed 0.1% (w/w) AY-9944 (in chow) for 14-days, a complete inhibition of DHCR activity and a significant reduction in serum total cholesterol level were observed. However, the level of hepatic DHCR mRNA fell only slightly, suggesting that AY-9944 may act more rapidly at the protein level than at the level of transcription of the DHCR gene under these conditions.

Amino Acid Sequence↗
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↗
PubMed1998

Dna2 of Saccharomyces cerevisiae possesses a single-stranded DNA-specific endonuclease activity that is able to act on double-stranded DNA in the presence of ATP.

To gain further insights into the biological functions of Dna2, previously known as a cellular replicative helicase in Saccharomyces cerevisiae, we examined biochemical properties of the recombinant Dna2 protein purified to homogeneity. Besides the single-stranded (ss) DNA-dependent ATPase activity as reported previously, we were able to demonstrate that ssDNA-specific endonuclease activity is intrinsically associated with Dna2. Moreover, Dna2 was capable of degrading duplex DNA in an ATP-dependent fashion. ATP and dATP, the only nucleotides hydrolyzed by Dna2, served to stimulate Dna2 to utilize duplex DNA, indicating their hydrolysis is required. Dna2 was able to unwind short duplex only under the condition where the endonuclease activity was minimized. This finding implies that Dna2 unwinds only partially the 3'-end of duplex DNA and generates a stretch of ssDNA of limited length, which is subsequently cleaved by the ssDNA-specific endonuclease activity. A point mutation at the conserved ATP-binding site of Dna2 inactivated concurrently ssDNA-dependent ATPase, ATP-dependent nuclease, and helicase activities, indicating that they all reside in Dna2 itself. By virtue of its nucleolytic activities, the Dna2 protein may function in the maintenance of chromosomal integrity, such as repair or other related process, rather than in propagation of cellular replication forks.

Adenosine Triphosphate↗
PubMed1998

Development of a medical record and radiographic image transmission system using a high-speed communication network.

A medical record and radiographic image transmission system has been developed using a high-speed communication network. The databases are designed to store and transmit the data acquired from the scanner. To maximally utilize the communication bandwidth, the medical records and radiographic images are compressed using the G3 facsimile and JPEG coding standard method, respectively. TCP/IP, OOP and Windows-based system software enable a modular design, future expandability, open system interconnectivity, and diverse image manipulation functions.

Computer Communication Networks↗
PubMed1998

Implementation of a low-cost PACS/CR for clinical use in Yonsei Cardiovascular Center.

The PACS/CR for clinical use in Yonsei Cardiovascular Center has been designed and implemented. Our system is open architecture to comply with emerging standards such as DICOM. database SQL, TCP/IP and to reduce operational and maintenance costs, PC-based low cost workstations running Microsoft Windows, database as Microsoft SQL based on Client/Server, Long-term storage using CD-ROM Jukebox are developed. Also, auto routing and image pre-fetching are implemented.

Ambulatory Care Facilities↗
PubMed1997

Cholesterol biosynthesis from lanosterol: development of a novel assay method and characterization of rat liver microsomal lanosterol delta 24-reductase.

The membrane-bound sterol delta 24-reductase (24-reductase) catalyses anaerobic reduction of the 24(25)-enes of lanosterol and other obligatory intermediates of cholesterol biosynthesis from lanosterol. A novel assay method and properties of the 24-reductase are described. More than a 120-fold induction of the 24-reductase activity was achieved by feeding rats a diet containing 5% cholestyramine plus 0.1% lovastatin in chow and by modulating diurnal variation. With this enzyme induction condition, lanosterol was converted efficiently into dihydrolanosterol in both intact hepatic microsomes and freshly isolated hepatocytes only when either miconazole or CO was added to inhibit 14 alpha-demethylation of lanosterol. AR45 cells, which are deficient in 14 alpha-methyl demethylase (14 alpha-DM), exhibit lanosterol 24-reductase activity without addition of either CO or miconazole. Conversely, inhibition of the 24-reductase was not required for the expression of 14 alpha-DM activity. Studies on the substrate specificities for the 24-reductase using different 24(25)-enes showed that the most reactive substrate was 5 alpha-cholesta-7,24-dien-3 beta-ol, which exhibited a maximal 18-fold higher kcat than that of lanosterol without the aid of the 14 alpha-DM inhibitor. In addition, both the kinetic behaviour of lanosterol substrate in relation to the 24-reductase and a non-competitive inhibition mode of U18666A (Ki 0. 157 microM) as well as Triparanol (Ki 0.523 microM), two well-known 24-reductase inhibitors, were determined. On the basis of our new findings on the preferred substrate and on the negative effect of 14 alpha-DM on the 24-reductase, we suggest that C-24 reduction of sterols takes place straight after sterol delta 8-->7 isomerization of zymosterol, which occurs several steps after C-32 demethylation of lanosterol in the 19-step pathway of cholesterol biosynthesis from lanosterol.

Animals↗
PubMed1997

Functioning islet cell tumor of the pancreas. Localization with dynamic spiral CT.

PURPOSE: The purpose of this study was to evaluate the usefulness of dynamic spiral CT, including multidimensional reformation, in the detection and localization of islet cell tumors of the pancreas. MATERIAL AND METHODS: Seven patients with histopathologically proven functioning islet cell tumors of the pancreas were studied with 2-phase contrast-enhanced spiral CT. Scanning of the arterial phase and late phase was started 30 s and 180 s, respectively, after injection of 100 ml of contrast medium at a rate of 3 ml/s. RESULTS: Axial images in the arterial phase depicted the lesions in 5 patients, but in the late phase in only one patient. Multiplanar reformatted images of the arterial phase depicted the lesions in all 7 patients. Maximal intensity projection images demonstrated all lesions with information of their relationship to the vascular structure. CONCLUSION: Dynamic spiral CT with scanning during the arterial phase and retrospective multidimensional reformation is useful for preoperative detection and localization of small islet cell tumors of the pancreas.

Adenoma, Islet Cell↗
PubMed1997

Decreased gastric proliferation of foveolar epithelial cells after the eradication of Helicobacter pylori.

Increased epithelial cell proliferation is associated with an increased risk of gastric carcinoma. Helicobacter pylori infection is an established risk factor for gastric cancer and the organism has recently been classified as a group I carcinogen by an IARC working group. In this study, we describe differences in gastric epithelial cell proliferation between a H. pylori eradicated group (n = 21) and a not eradicated group (n = 8) after anti-H. pylori eradication therapy to show that increased cell proliferation is associated with H. pylori infection. H. pylori infection was determined by rapid urease test and immunohistochemical method with anti-H. pylori polyclonal antibody. Gastric epithelial cell proliferation was assessed using immunohistochemical method using Ki-67 monoclonal antibody. Ki-67 positive cells in H. pylori associated chronic active gastritis were observed in the glandular neck and the upper portion of foveolar epithelium. Patients who cleared their H. pylori infections showed a significant decrease of Ki-67 labeling index after therapy (0.73 +/- 0.10 vs. 0.48 +/- 0.08, p < 0.01). By contrast, Ki-67 labeling index before and after treatment in patients who remained positive for H. pylori showed no significant difference (0.78 +/- 0.08 vs 0.74 +/- 0.10, p > 0.05). These results indicate that H. pylori infection increases the proliferation of gastric foveolar epithelium, which is reduced by the eradication therapy. We suggest that anti-H. pylori eradication therapy can prevent mucosal cell proliferation to be closely associated with gastric carcinogenesis.

Adolescent↗
PubMed1996

Spinal anaesthesia with 0.25% hyperbaric bupivacaine for Caesarean section: effects of volume.

To investigate the safety and efficacy of 0.25% hyperbaric bupivacaine for spinal anaesthesia in Caesarean section, we studied 60 parturients allocated randomly to one of three groups. According to the patient's height, groups 1, 2 and 3 received 3.2-3.6 ml (8-9 mg), 3.6-4.0 ml (9-10 mg) and 4.0-4.4 ml (10-11 mg) of 0.25% bupivacaine in 5% glucose, respectively. Subarachnoid injection was performed in the right lateral decubitus position, and parturients were then turned immediately supine with left uterine displacement. Mean spread of sensory analgesia was significantly higher in group 3 (T2-3) than in groups 1 and 2 (T4-5 in each group). Duration of sensory analgesia was significantly longer in groups 2 and 3 than in group 1. Complete motor block of the lower extremities occurred in all patients but in only one in group 1. Onset time and duration of motor block were not significantly different between the three groups. The incidence of hypotension was significantly higher in group 3 (75%) than in groups 1 and 2 (40% in each group). The efficacy of intraoperative analgesia was significantly greater in groups 2 and 3 than in group 1. The incidence of patients requiring analgesics during operation was significantly lower in groups 2 (25%) and 3 (10%) than in group 1 (70%). There was no difference in neonatal condition between the three groups. Spinal anaesthesia with 3.6-4.0 ml of 0.25% bupivacaine in 5% glucose was satisfactory for Caesarean section.

Adult↗
PubMed1995

[Magnetic resonance imaging of renal lymphoma with computed tomography correlation].

The magnetic resonance (MR) imaging and computed tomography (CT) findings in four patients (five kidneys) with non-Hodgkin's lymphoma involving the kidneys and perirenal spaces are presented. The patterns of disease in each case were as follows: bilateral renal nodules, infiltration in the perirenal space, infiltration in the perirenal space with renal involvement, and direct invasion from contiguous retroperitoneum. On plain CT, the lesions showed slight hyperdensity (three kidneys) and isodensity (two kidneys) as compared with normal renal parenchyma. But all lesions appeared as hypodense masses with more definite margins after contrast enhancement. MR imaging findings showed iso- or slight hypointense masses on T1-weighted images and definite hypointense masses on T2-weighted images as compared with the signal intensity of the renal cortex. Dynamic imaging and conventional delayed T1-weighted imaging following Gd-DTPA injection showed no significant enhancement of the lesions. In comparison with contrast enhanced CT, despite its poorer resolution, T2-weighted MR imaging showed nearly the same accuracy in the evaluation of number and extent of the lesions without contrast medium administration. MR imaging was also useful to evaluate the patency of vessel lumen surrounded by tumor mass and to determine the location and extent of huge lesions by its multiplanar imaging capabilities.

Aged↗
PubMed1994

Assessment of reducibility of ileocolic intussusception in children: usefulness of color Doppler sonography.

PURPOSE: To assess the diagnostic usefulness of ultrasonography (US) in intussusception in children and determine whether color Doppler sonography (CDS) can indicate bowel viability and help in prediction of reducibility. MATERIALS AND METHODS: US was used to examine 176 children in whom the presence of intussusception was clinically suspected. CDS was performed in 64 patients with 65 cases of intussusception proved with US. RESULTS: The positive US findings were confirmed with air enema; the negative findings, with air enema in 46 patients and clinical follow-up in 66 patients (100% specificity and sensitivity). CDS indicated blood flow in 62 of 65 cases of intussusception; pneumatic reduction was achieved in 58 (94%) of these 62 cases. Four patients (6%) underwent manual reduction of viable bowel; three patients (5%) who had no color Doppler signal underwent segmental resection. The difference in reduction rates based on blood flow was statistically significant (P = .0008). CONCLUSION: US is sensitive and specific in the diagnosis of intussusception, and CDS is a promising predictor of bowel viability.

Air Pressure↗
PubMed1992

Diagnosis of acute appendicitis in pregnant women: value of sonography.

OBJECTIVE: The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limited because of the potentially hazardous effects of radiation. This study was done to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women. SUBJECTS AND METHODS: We obtained sonograms in 45 pregnant women with clinically suspected acute appendicitis. Our sonographic technique included graded-compression scanning. The left lateral decubitus position was used in the third trimester of gestation. The sonographic criterion for the diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter greater than 7 mm. We correlated the sonographic findings with the surgical findings in 22 cases and with the results of clinical follow-up in 23 cases. RESULTS: Sonography could not be used to make the diagnosis in three (7%) of 45 patients because the size of the gravid uterus prevented use of the graded-compression technique. These three patients were in the third trimester of pregnancy (greater than 35 weeks' gestation). Sonographic findings were used as a basis for diagnosis in 42 cases. Acute appendicitis was diagnosed on the basis of sonograms in 16 patients, and in all but one of these patients, acute appendicitis was confirmed by surgical and pathologic findings. In the 42 cases in which the imaging findings indicated the diagnosis, the overall sensitivity of sonography was 100%, the specificity was 96%, and the accuracy was 98%. CONCLUSION: Our experience suggests that graded-compression sonography is a valuable procedure for detecting acute appendicitis in pregnant women despite technical difficulty in performing it during the third trimester of pregnancy.

Acute Disease↗
PubMed1981

Visual evoked potentials in occipital lobe lesions.

Recording of visual evoked potentials (VEPs) to pattern reversal is considered to be a reliable diagnostic procedure for examining patients with anterior visual pathway lesions (optic nerves and chiasm). Less consistent results have been reported in studies of more posterior lesions. The VEPs were recorded in 20 patients with occipital lobe lesions. A maximal VEP response (P94) was recorded at the scalp electrodes situated over the involved occipital lobes and contralateral to the hemianoptic visual field defect, indicating a positive correlation of unilateral occipital lobe lesions, homonymous visual field loss, and the VEP abnormality.

Adult↗
PubMed1981

Visual evoked potentials in sarcoidosis.

The visual evoked potential to pattern reversal was recorded in 50 patients with sarcoidosis. Abnormalities of latency and amplitude were found in 15 patients (30%), including all 4 patients with clinically evident brain disease and 4 of 17 patients with overt ocular disease. Twenty-nine patients had no clinical evidence of ocular or neurologic disease, and 7 of them (24%) had abnormalities of the VEP, implying subclinical sarcoid lesions in structures at the base of the brain.

Adult↗