PubMed Health⌕ Search

Biomedical subjects

B G Choi

Publications and source records attributed to B G Choi.

At least 19 recordsLinked to original sources
PubMed2006

The role of high-density lipoprotein cholesterol in the prevention and possible treatment of cardiovascular diseases.

Despite significant progress in the management of atherosclerosis and its resultant complications, cardiovascular disease remains the principal cause of death in the world. The National Cholesterol Education Project Adult Treatment Panel III (NCEP ATP III) recognizes low levels of high-density lipoprotein cholesterol (HDL) as a risk factor for coronary heart disease (CHD) and high levels of HDL as a risk-reducing factor; however, the elevation of HDL as a specific therapeutic target for the prevention and treatment of CHD has yet to be accepted on the same level as low-density lipoprotein (LDL)-reducing therapies. Current HDL elevators including nicotinic acid, fibric acid derivatives, peroxisome proliferator activated receptor (PPAR) agonists and statins also affect other lipid constituents which make interpretation of the clinical trials of these drugs difficult in teasing out the independent effect of HDL elevation. Ample laboratory investigation suggests that HDL elevation would reduce atherosclerotic burden through multiple independent mechanisms. In this review, we explore HDL biology, its potential mechanisms in the treatment of atherosclerotic disease, and promising new drugs with HDL-raising activity.

Animals↗
PubMed2004

Gallbladder wall thickening: MR imaging and pathologic correlation with emphasis on layered pattern.

The aim of this study was to correlate MR findings of gallbladder wall thickening with pathologic findings on the basis of the layered pattern and to evaluate the diagnostic value of MR imaging in gallbladder disease. We retrospectively evaluated the source images of HASTE sequences for MR cholangiography in 144 patients with gallbladder wall thickening. The layered pattern of thickened wall was classified into four patterns. Type 1 shows two layers with a thin hypointense inner layer and thick hyperintense outer layer. Type 2 has two layers of ill-defined margin. Type 3 shows multiple hyperintense cystic spaces in the wall. Type 4 shows diffuse nodular thickening without layering. MR findings of a layered pattern of thickened gallbladder were well correlated with histopathology. Chronic cholecystitis matched to type 1, acute cholecystitis corresponded to type 2, adenomyomatosis showed type 3, and the gallbladder carcinomas showed type 4. All four layered patterns were associated with PPV of 73% or greater, sensitivity of 92% or greater and specificity of 95% or greater. Our results indicate that MR findings of gallbladder wall thickening are characteristic in each entity and correlate well with pathologic findings. The classification of the layered pattern may be valuable for interpreting thickened gallbladder wall.

Adult↗
PubMed2002

Primary antiphospholipid syndrome presenting with abdominal angina and splenic infarction.

The antiphospholipid syndrome is an autoimmune hypercoagulability syndrome in which a wide variety of thromboembolic diseases may occur. Gastrointestinal manifestations associated with vascular occlusion include Budd-Chiari syndrome, hepatic and splenic infarction, pancreatitis, omental and intestinal infarction, and esophageal variceal bleeding due to portal vein thrombosis, but chronic mesenteric ischemia associated with mesenteric arterial thrombosis is very rare in this syndrome. We experienced a female patient with primary antiphospholipid syndrome with abdominal angina and splenic infarction associated with celiac trunk and mesenteric arterial thromboses. This is the first report describing chronic mesenteric ischemia and splenic infarction in a patient with primary antiphospholipid syndrome.

Abdominal Pain↗
PubMed2001

Interactive 3-dimensional segmentation of MRI data in personal computer environment.

We describe a method of interactive three-dimensional segmentation and visualization for anatomical magnetic resonance imaging (MRI) data in a personal computer environment. The visual feedback necessary during 3-D segmentation was provided by a ray casting algorithm, which was designed to allow users to interactively decide the visualization quality depending on the task-requirement. Structures such as gray matter, white matter, and facial skin from T1-weighted high-resolution MRI data were segmented and later visualized with surface rendering. Personal computers with central processing unit (CPU) speeds of 266, 400, and 700 MHz, were used for the implementation. The 3-D visualization upon each execution of the segmentation operation was achieved in the order of 2 s with a 700 MHz CPU. Our results suggest that 3-D volume segmentation with semi real-time visual feedback could be effectively implemented in a PC environment without the need for dedicated graphics processing hardware.

Adult↗
PubMed2001

Human brain mapping of auditory imagery: event-related functional MRI study.

We used event-related fMRI methodology to investigate human brain activity during auditory imagery. A series of susceptibility-weighted MR images covering the whole brain were acquired to obtain blood oxygenation level-dependent (BOLD) signal changes associated with the imagery event of hearing simple monotone. Group analysis across the 12 right-handed subjects revealed activations in the medial and inferior frontal gyri, precuneus, middle frontal gyri, superior temporal gyri, and anterior cingulate gyri. Bilateral primary and secondary auditory areas in the superior temporal gyri also exhibited the event-related MR signal changes. The proposed method allowed for the analysis of brain areas responsive to the event of auditory imagery while our results suggest that auditory imagery and actual audition share common neural substrates.

Acoustic Stimulation↗
PubMed2001

Correlation of color Doppler sonographic findings with pH measurements in gastroesophageal reflux in children.

PURPOSE: We conducted a prospective study of color Doppler sonography in children with suspected gastroesophageal reflux (GER). The purpose of this study was to compare the accuracy of color Doppler sonography with that of continuous 24-hour pH monitoring of the esophagus in diagnosing GER and to determine how to interpret the reflux episodes detected on color Doppler sonography in children at high risk for reflux. METHODS: Color Doppler sonography and 24-hour esophageal pH monitoring were performed in 54 children ranging in age from 2 months to 10 years (mean, 3 years). The stomach of each patient was filled for adequate gastric distention just before the color Doppler sonographic examination. We counted the number of reflux episodes over a period of 15 minutes. One day after the sonographic examination, the reflux was evaluated with esophageal pH monitoring, and the resultant reflux index (ReI) was obtained. The ReI was considered to be pathologic when it was equal to or greater than 11.99%. The number of refluxes on color Doppler sonography and the ReI were correlated for each patient. RESULTS: The 2 tests showed an 81.5% agreement in the detection of GER. When pH monitoring was taken as the reference test, color Doppler sonography had a high sensitivity (95.5%) for diagnosing GER but a very low specificity (11.0%), with a positive predictive value of 84.3% and a negative predictive value of 33.3%. There was no statistically significant correlation between the frequencies of GER detected on color Doppler sonography and the ReIs on pH monitoring (p = 0.1103). There was no correlation between the reflux grades on sonography and the ReI grades on pH monitoring (p = 0.422). CONCLUSIONS: Color Doppler sonography is highly sensitive and easier to use than pH monitoring. Although there are no definite criteria for evaluating the severity of GER on color Doppler imaging, this modality may be useful in screening children for GER.

Child↗
PubMed2001

Characteristic MR findings of cervical pregnancy.

The aim of this study was to define the characteristic MR findings of cervical pregnancy. Twelve patients with cervical pregnancy underwent MRI because of difficulty in the diagnosis by ultrasonography, human chorionic gonadotropin assessment, and other clinical evaluations. The assessment of MRI included size and location of the lesion, margin, MR signal intensity, rim of low-signal intensity, enhancement pattern, appearance of enhancing solid component, parametrial change, endometrial change, pelvic fluid collection, and ovarian change. All cases showed ill-marginated mass with very heterogeneous signal intensity on T2-weighted images, irregular internal high-signal intensities on T1-weighted images, a partial or circumferential rim of low-signal intensity, dense irregular peripheral enhancement and enhancing papillary solid components with accompanying tubular signal voids, and variably increased parametrial vascularities. This heterogeneous hemorrhagic mass with densely enhancing papillary solid components may be the typical MR finding for cervical pregnancy. J. Magn. Reson. Imaging 2001;13:918-922.

Adult↗
PubMed2001

Proton magnetic resonance chemical shift imaging (1H CSI)-directed stereotactic biopsy.

INTRODUCTION: To add metabolic information during stereotactic biopsy target selection, the authors adopted proton chemical shift imaging (1H CSI)-directed stereotactic biopsy. Currently, proton single voxel spectroscopy (SVS) technique has been reported in stereotactic biopsy. We performed 1H CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, and evaluated the pathological results. PATIENTS AND METHOD: The 1H CSI-directed stereotactic biopsy was performed in four patients. 1H CSI and conventional Gd-enhancement stereotactic MRI were performed simultaneously after the fitting of a stereotactic frame. After reconstructing the metabolic maps of N-acetylaspartate (NAA)/phosphocreatine (Cr), phosphocholine (Cho)/Cr, and Lactate/Cr ratios, focal areas of increased Cho/Cr ratio and Lac/Cr ratios were selected as target sites in the stereotactic MR images. RESULTS: 1H CSI is possible with the stereotactic headframe in place. No difficulty was experienced performing 1H CSI or making a diagnosis. Pathological samples taken from areas of increased Cho/Cr ratios and decreased NAA/Cr ratios provided information upon increased cellularity, mitoses and cellular atypism, and facilitated diagnosis. Pathological samples taken from areas of increased Lac/Cr ratio showed predominant feature of necrosis. CONCLUSION: 1H CSI was feasible with the stereotactic headframe in place. The final pathological results obtained were concordant with the local metabolic information from 1H CSI. We believe that 1H CSI-directed stereotatic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting.

Adult↗
PubMed2001

The findings of ruptured hepatocellular carcinoma on helical CT.

To evaluate the helical CT findings of ruptured hepatocellular carcinoma (HCC), 12 patients with ruptured HCC were reviewed with regard to the tumour's location, size and contour protrusion, the appearance of the mass, the enhancement pattern, multiplicity and secondary changes. All ruptured tumours were located at the periphery of the liver and had a protruding contour. The maximum diameter of tumours ranged from 2 cm to 16 cm. Discontinuity of the hepatic surface was seen in 11 cases. In eight cases, CT images during the arterial phase showed a non-enhancing low attenuating lesion with focal discontinuity and peripheral rim enhancement. Seven cases showed separation of tumour content from the peripheral enhancing rim and intraperitoneal rupture of tumour content into the perihepatic space. Because of the similar appearance to an enucleated orbital globe with remaining sclera, this was termed the "enucleation sign". As well as ruptured masses, 10 cases with non-ruptured masses also showed a non-enhancing low attenuating pattern. Seven cases showed a haematoma with high attenuation around the ruptured mass. The peripheral location, protruding contour, discontinuity of the hepatic surface and surrounding haematoma are helpful signs in the diagnosis of ruptured HCC. The "enucleation sign" may be a characteristic finding in ruptured HCC.

Adult↗
PubMed2001

CT differentiation of pneumonic-type bronchioloalveolar cell carcinoma and infectious pneumonia.

The objective was to analyse the potential of CT to distinguish pneumonic-type bronchioloalveolar cell carcinoma (BAC) from infectious pneumonia. The study consisted of 21 patients with pathologically proven BAC and 30 patients with infectious pneumonia. Both groups of patients had patchy or diffuse consolidation of more than half the area of a lobe or lobes on CT. CT findings in these two groups were compared with regard to morphological appearance, including CT angiogram, air bronchogram, mucous bronchogram, contrast enhancement pattern, pseudocavitation, cavity with air-fluid level, location, satellite lesion, ground-glass opacity and bulging of the interlobar fissure. Air-filled bronchi were morphologically analysed as dilatation, stretching, sweeping, widening of the branching angle, squeezing and crowding. Lymphadenopathy and pleural effusion were also analysed. CT findings favouring the diagnosis of BAC included an air-filled bronchus within the consolidation with stretching, squeezing, sweeping, widening of the branching angle and bulging of the interlobar fissure (p<0.05). It is concluded that CT may be helpful in differentiating pneumonic-type BAC from infectious pneumonia if the air-filled bronchus within the consolidation shows stretching, squeezing, widening of the branching angle or bulging of the interlobar fissure.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2001

Vinorelbine-associated myelopathy in a patient who previously received paclitaxel: a case report.

Vinorelbine seems to cause less neurotoxicity than other vinca alkaloids because of its selective activity on mitotic cells over axonal microtubules. Clinical trials report very mild peripheral neurotoxicity with distal paresthesiae and there are no reports of myelopathy in these series of patients. The authors describe a patient who developed a rare event of myelopathy while on vinorelbine for non-small-cell lung cancer.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Metabolic changes in pericontusional oedematous areas in mild head injury evaluated by 1H MRS.

In order to define metabolic brain changes associated with mild traumatic brain injury, proton magnetic resonance spectroscopy (MRS) was performed in patients with regional brain contusion and 13-15 of initial GCS score. The authors measured N-acetylaspartate(NAA)/creatine(Cr) ratio and lactate signal on in vivo proton MRS, which indicated cell loss and ischaemic dAmage respectively, in pericontusional oedematous areas (region of interest; ROI) adjacent to traumatic brain contusion on brain MRI to determine possible metabolic changes. The metabolic ratio of NAA/Cr and lactate/Cr peaks was measured both in the ROI and a corresponding region of the contralateral hemisphere (ROC) in seven patients and twenty-five normal control. In initial NAA/Cr ratios, the values of ROIs were significantly lower than those of the control (p = 0.009), but there was no difference either between ROI and ROC (p = 0.410) or between ROC of patients and the control (p = 0.199). In lactate/Cr ratios, the ROI in all seven patients and the ROC in two showed increased lactate signals. The lacate/Cr ratios of the ROIs were significantly elevated as compared to those of the ROCs (p = 0.02) and the control (p = 0.015). In 2-month follow up, lactate signals were absent or significantly reduced (p = 0.015). In no patients, clinical or radiological deterioration has been observed. Our results demonstrate that there is significant neuronal dysfunction in pericontusional oedematous areas as indicated by NAA/Cr ratios in the patients with mild head injury at both early and late stages. And there are significant ischaemic changes as indicated by increase of lactate level in ROI at early stage. These findings suggest that pericontusional oedematous areas can be vulnerable to secondary brain insults even in the patients with mild head injury.

Adolescent↗
PubMed2000

Synthesis and antiviral activity of novel methylene cyclopropyl nucleosides.

Novel exomethylene cyclopropyl nucleosides were synthesized as potential antiviral agents. The key intermediate 5 was synthesized in 4 steps, from Feists acid 1 and was condensed with purine derivatives by the SN2 type reaction to give some cyclopropyl nucleosides. The synthesized nucleosides did not showed any significant antiviral activity against HSV-1, HSV-2, HCMV, HIV-1, HIV-2, and HBV up to 100 microM.

Antiviral Agents↗
PubMed2000

A phase II study of a daily x4 schedule of vinorelbine plus cisplatin for advanced non-small cell lung cancer.

BACKGROUND: Because dose intensity may be important as a determinant response to vinorelbine, we explored the possibility of increasing the dose intensity of vinorelbine on a daily x4 schedule. METHODS: Between February 1998 and March 1999, 31 patients with previously untreated advanced non-small cell lung cancer were enrolled. Vinorelbine 15 mg/m2 and cisplatin 20 mg/ m2 were administered intravenously daily for 4 days and repeated every 21 days. RESULTS: A total 96 cycles were administered (median 3, range 1-6); 42% of vinorelbine and 39% of cisplatin injections were dose-reduced or delayed owing to toxicity. The actual dose intensity (DI) of vinorelbine was 17.7 mg/m2/week and that of cisplatin was 24 mg/m2/week. These figures represent 88 and 90% of the theoretical DI, respectively. The overall response rate was 40% (12/30, one CR). The main toxicity was myelosuppression: granulocytopenia WHO grade 3 and 4 in 24 patients (77%) and thrombocytopenia grade 3 in two patients (6%). The non-hematological toxicity was mild and tolerable. After a median follow-up of 7.5 months (range 3-21 months), the median progression-free survival and overall survival times were 5 months (95% CI, 3.8-6.2) and 8 months (95% CI, 4.5-11.5), respectively. CONCLUSIONS: This regimen has a comparable therapeutic activity in patients with advanced lung cancers. However, despite supportive care there were excessive hematological toxicities. In view of increased toxicity and similar efficacy, this regimen is not indicated outside a clinical trial.

Adult↗
PubMed2000

Cleft lip nose correction with onlay calvarial bone graft and suture suspension in Oriental patients.

To correct the secondary cleft lip nose deformity in Oriental patients, many alar cartilage mobilization and suspension techniques have been developed. However, these techniques have critical limitations. One of the limitations is the suspension vector, and another is suspension power. The suspension vector is from inferior to superior and from the deformed alar cartilage to the normal alar cartilage. Thus, the vector is not suitable for normal nasal tip projection. The suspension power is not satisfactory because Oriental people have underdeveloped, thin alar cartilages and thick skin. So, the suspended, deformed alar cartilage may relapse and pull the normal alar cartilage to the deformed side. To overcome these limitations, the authors use the cantilever calvarial bone graft for tip projection; it also serves as a strong, rigid framework for cartilage and soft-tissue suspension. Using these techniques, the authors can create normal nasal tip projection and a normal looking nasal aperture.

Abnormalities, Multiple↗