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J Y Choi

Publications and source records attributed to J Y Choi.

161 records · Page 9Linked to original sources
PubMed1991

Study on Doppler waveforms from the fetal cardiovascular system.

In order to see whether Doppler parameters from the fetal cardiovascular system change with fetal growth and to compare Doppler values from the various sites, a total of 274 Doppler studies on 73 human fetuses were analyzed. With advancing gestation, the heart rate decreased, the diastolic filling period of both atrioventricular valves increased, and the systolic ejection time of both semilunar valves remained unchanged. Most of the Doppler parameters from the 4 cardiac valves, the aortic arch, the branch pulmonary artery, and the ductus arteriosus increased with increasing gestation. Doppler waveforms from the branch pulmonary artery, the ductus arteriosus, and the aortic arch each had a distinct shape. More study is needed to define the exact relationship between the gestation period and the Doppler parameters and to determine whether Doppler parameters will be useful in assessing fetal heart function.

Cardiovascular System↗
PubMed1991

Homologous fibronectin enhances healing of excised wounds in rats.

In order to evaluate the effects of a topical application of homologous fibronectin on the healing of skin wounds, we made 2 excisional wounds on the back skin of each rat, applied ointment with or without fibronectin purified from citrated homologous plasma, and evaluated the effect according to wound size and microscopic findings. Excised lesions treated with carrier alone, but the difference was significant only in the early phase of wound healing, 2 and 3 days, according to wound size and microscopic changes. A significant decrease in wound size could be found in both groups, treated with ointment containing and not containing fibronectin, between day 4 and 9 when wound contraction was a major contributor to wound closure. Therefore it can be concluded that topical application of fibronectin has a beneficial effect on wound healing during its early phase, but no significant influence on wound contraction.

Administration, Topical↗
PubMed1990

Anomalous subaortic position of the brachiocephalic vein (innominate vein): an echocardiographic study.

In 24 (0.98%) of 2457 patients with congenital heart disease the brachiocephalic vein was in an anomalous position below the aortic arch. This is a much higher proportion of such cases than reported so far. This high frequency may arise from differences in the study population and the method of diagnosis. This venous anomaly was more common in patients with tetralogy of Fallot or ventricular septal defect with pulmonary atresia. Patients with the venous anomaly were more likely to have a right aortic arch. The anomalous course of the brachiocephalic vein from the neck to the junction of the superior vena cava was shown by cross sectional echocardiography. In doubtful cases, Doppler study usually clarified the anatomical arrangement.

Aorta, Thoracic↗
PubMed1987

Absent right superior caval vein (vena cava) with normal atrial arrangement.

Eight cases of absent right superior caval vein (vena cava) with normal atrial arrangement from the Great Ormond Street database were reviewed. In each case the right subclavian vein and jugular vein drained into a persistent left superior caval vein through a bridging vein. In six cases the left superior caval vein drained into the right atrium by way of the coronary sinus, and in two cases it drained into the left atrium directly because of the complete unroofing of the coronary sinus. The frontal plane P wave axis was displaced leftwards and upwards in four out of seven cases in which an electrocardiogram was available. No case showed arrhythmia on a standard electrocardiogram preoperatively. Echocardiograms were available in four cases and in each case diagnosis of the anomalous connections of the systemic vein was possible. Only one third of the cases showed a crescentic shadow of the persistent left superior caval vein on chest x ray. A chest x ray and electrocardiogram do not provide the means of reliable diagnosis of this condition, though they may suggest the possibility of its existence. Definitive diagnosis requires cross sectional echocardiography or angiocardiography or both.

Child↗
PubMed1980

Adenosine diphosphate ribose pyrophosphohydrolase in human skin.

Adenosine diphosphate ribose (ADPR) pyrophosphohydrolase (ADPR-PPase), which catalyzes the hydrolysis of ADPR to yield adenosine monophosphate (AMP) and ribose-5'-phosphate, was assayed in human penile foreskin. Since ADPR is formed from nicotinamide adenine dinucleotide (NAD) by NAD glycohydrolase (NADase), NADase was also assayed in human skin. The skin tissue obtained by circumcision was separated into three layers; epidermis of the outer prepuce, epidermis of the inner prepuce, and dermis. ADPR-PPase was found to be present in all of the three layers with nearly equal activity. NADase was also present in the epidermis of both the outer and inner prepuce, being about two times higher in the latter, but no activity was found in the dermis. When expressed in units of the same specific activity; i.e., micromoles product formed per hour per mg protein, the ADPR-PPase of human skin had two to five times greater activity than did NADase. The ADPR-PPase of human skin was activated by Mg(+2), but inhibited by AMP and ATP. These results suggest that the breakdown of NAD occurs in human skin via ADPR to AMP and ribose-5'-phosphate by sequential action of NADase and ADPR-PPase.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Magnetic resonance imaging of unroofed coronary sinus: three cases.

Unroofed coronary sinus is a rare cardiac anomaly in which communication occurs between the coronary sinus and the left atrium due to the partial or complete absence of the roof of the coronary sinus. It is usually associated with other cardiovascular anomalies, especially persistent left superior vena cava. It is often not discovered during cardiac catheterization without clinical suspicion. We report three cases of unroofed coronary sinus which were incidentally detected by magnetic resonance imaging.

Adolescent↗
PubMedDate not supplied

Morphology of tricuspid valve in pulmonary atresia with intact ventricular septum.

Pulmonary atresia with intact ventricular septum (PAIVS) is a rare congenital cardiac anomaly that has been classified into two types: one is a more frequent type having dysplasia of tricuspid valve (TV) with a small annulus, underdeveloped right ventricle (RV) with a hypoplastic cavity and a hypertrophic wall; the other type has severe dysplasia of TV and dilatation of RV, right atrium (RA), and right atrioventricular junction with thinning of the RV wall. We performed a morphologic study on 11 autopsied hearts with PAIVS, giving particular emphasis to the variation of morphology of the TV. We could classify these hearts into 3 groups according to the degree of right ventricular development. In the first group of 7 cases (type I), the RVs were underdeveloped. Thick leaflets, restricted valve apparatus with short chordae, and small annuli were characteristics of the TV. In the second group of 3 cases (type II), the RVs showed marked enlargement of the cavity and thinning of the wall. The TV showed redundant, dysplastic, sail-like anterior leaflets, and the downward displacement of septal leaflet and/or posterior leaflet, which are the findings frequently observed in Ebstein's malformation. The RVs were dilated and with partially unguarded tricuspid orifice. The septal leaflet of the TV was dysplastic and, in two cases, the septal leaflet showed chordal structure at the upper surface facing the RA, which is a peculiar finding that has not been described in the literature. The remaining case was a heart with a moderately developed RV (type III). The TV showed mildly dysplastic appearance and we classify this as a separate type, because we could expect the best surgical results in this type. This type had optimal size of RV and the mildest degree of dysplasia of TV. In PAIVS, the morphology of TV correlates well with the type of the right ventricular development.

Child, Preschool↗
PubMedDate not supplied

Secondary cardiac tumor in children.

We describe our clinical experience of eight cases of secondary cardiac tumor. The pathology of the tumors were lymphoma (three), Wilms' tumor (two), malignant teratoma (one), neuroblastoma (one), and pleuropulmonary blastoma (one). Metastatic sites were the right atrium in Wilms' tumor and neuroblastoma, the left atrium in pleuropulmonary blastoma and malignant teratoma, and multiple sites in lymphoma. Primary masses in the mediastinum extended directly to the heart (three lymphoma, malignant teratoma, pleuropulmonary blastoma). Wilms' tumor and neuroblastoma showed cardiac metastases through the inferior vena cava. Many cases revealed vague abnormal cardiovascular findings (symptoms in six; physical signs in five). In five cases surgery was performed to relieve the possible obstruction to flow and to identify the pathology (lymphoma in three, Wilms' tumor in one, and malignant teratoma in one). Chemotherapy prior to operation resulted in the disappearance of the intracardiac masses in each case of Wilms' tumor and pleuropulmonary blastoma. All three patients with lymphoma died immediately after operation. Four died of multiple metastases or Pneumocystis pneumonia several months after operation. This study indicates that suspicion of a secondary cardiac tumor is crucial to early diagnosis. Because of the poor postoperative outcome, surgery for secondary cardiac tumors should be done cautiously only in cases with definite hemodynamic decompensation.

Antineoplastic Agents↗
PubMedDate not supplied

Gating provides improved accuracy for differentiating artifacts from true lesions in equivocal fixed defects on technetium 99m tetrofosmin perfusion SPECT.

BACKGROUND: Because equivocal fixed perfusion defects on single photon emission computed tomography (SPECT) often cause a diagnostic dilemma in patients with suspected coronary artery disease (CAD), we used receiver-operating characteristic (ROC) curve analysis to evaluate the degree of increased accuracy provided by adding gated images for interpretation of such cases. METHODS AND RESULTS: One hundred five (29%) of 365 consecutive patients undergoing technetium 99m tetrofosmin gated SPECT for evaluation of CAD demonstrated an equivocal fixed defect. Two independent observers graded the probability for true lesion with a 5-point system over 3 steps of interpretation: reviewing tomographic images alone (step 1), adding projection images (step 2), and adding gated cine images (step 3). Based on clinical criteria, 66 patients were categorized as disease negative and 25 as disease positive, while the final diagnosis was undetermined in 14 cases. Diagnostic performance was significantly higher at step 3 than at step 1 for both observers (p < 0.05 and < 0.0001) and at step 2 for observer B (p < 0.005). The maximum accuracy increased from 78.0% to 80.2% at step 2 to 84.6% to 86.8% at step 3. Moreover, the agreement of interpretation between the 2 observers was higher at step 3 (kappa = 0.53) than at step 1 (kappa = 0.29) or step 2 (kappa = 0.25). CONCLUSION: In patients showing an equivocal fixed defect on 99mTc tetrofosmin SPECT, gated cine images provide improved differential accuracy and enhanced objectivity of interpretation by reducing interobserver variance.

Artifacts↗
PubMedDate not supplied

Iodine-123 MIBG imaging before treatment of heart failure with carvedilol to predict improvement of left ventricular function and exercise capacity.

BACKGROUND: We examined whether cardiac sympathetic imaging with iodine-123 metaiodobenzylguanidine (MIBG) would predict improvement of left ventricular (LV) function and exercise capacity in patients with heart failure after treatment with carvedilol. METHODS AND RESULTS: Eighteen patients with heart failure and 5 control subjects underwent I-123 MIBG imaging. Heart-to-mediastinum ratios at 20 minutes and 3 hours and myocardial washout rates (WR) were measured. Of the 18 patients, 11 were randomized to receive carvedilol medication, whereas the remaining 7 received a placebo. Only the carvedilol group demonstrated a significant improvement in both heart failure functional class and LV ejection fraction (EF) 1 year after the start of medication. Within the carvedilol group, MIBG WR showed a significant inverse correlation with improvement in LVEF (rho = -0.74, P =.02). The diagnostic accuracy of WR for predicting EF response to carvedilol was 91%. WR also appeared to be inversely related to the peak oxygen consumption rate (rho = -0.65, P =.08), although this did not reach statistical significance. CONCLUSION: I-123 MIBG imaging appears useful in predicting which patients with heart failure are likely to show the most improvement in LV function and exercise capacity after carvedilol treatment. Further studies in this area appear to be warranted.

3-Iodobenzylguanidine↗
PubMedDate not supplied

Focal cortical dysplasia: comparison of MRI and FDG-PET.

PURPOSE: The purpose of this work was to compare the use of MRI and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the diagnosis of focal cortical dysplasia (FCD). METHOD: Nineteen patients with surgically proven FCD were analyzed retrospectively. MRI was performed in all patients, and FDG-PET was performed in 17 patients. We compared the MR and FDG-PET findings of FCD according to the histologic findings that were classified into three grades. RESULTS: Four cases were classified as Grade I, 4 cases as Grade II, and 11 cases as Grade III FCD. The lesions were detected on MRI in 9 (82%) of the 11 patients with Grade III FCD and in only 1 (13%) of the 8 patients with Grade I and II FCD. Cortical hypometabolism of the lesion was revealed on FDG-PET in 6 (86%) of the 7 patients with Grade I and II FCD and in 9 (90%) of the 10 patients with Grade III FCD. The extent of the cortical abnormality was larger on FDG-PET than on MRI in 11 (65%) of the 17 patients. CONCLUSION: FDG-PET is more useful in delineating the cortical abnormality in patients with mild degrees of FCD. The extent of the lesion was larger or similar on FDG-PET compared with that of the MRI.

Adolescent↗
PubMedDate not supplied

Efficacy of MRI in complicated congenital heart disease with visceral heterotaxy syndrome.

PURPOSE: The authors' goal was to assess the diagnostic accuracy and clinical effect of MRI compared with echocardiography and catheterization in the evaluation of cardiac defects with situs ambiguous. METHOD: Twenty-two patients with visceral heterotaxy syndrome were included. RESULTS: Because situs determined by the relation between the pulmonary artery and bronchi showed most predominantly a tendency toward lateralization, this was regarded as the standard reference of situs determination. For the purpose of this study, patients were classified as having right isomerism (n = 13) or left isomerism groups (n = 9). MRI has several advantages compared with echocardiography or cardiac angiography for examining patients with situs ambiguous. (1) The bronchial, pulmonary arterial, and splenic situs can be readily determined, and discrepancies (n = 2) can be assessed easily. (2) Venoatrial connections are adequately imaged. In particular, all types of total and partial anomalous pulmonary venous return are delineated, regardless of whether restrictions of pulmonary blood flow or pulmonary venous obstructions are involved (n = 4). The courses of vertical veins were easily identified, and the prearterial position was revealed in only one of seven right isomerisms with total anomalous pulmonary venous return. The drain pattern of the hepatic vein can be visualized using three-dimensional spatial information and is useful for total cavopulmonary connection design. (3) Associated complicated cardiac anomalies, particularly the size or peripheral stenosis of the pulmonary arteries, may be evaluated, and this information is useful for palliative shunt operations. CONCLUSION: Because of its wide field of view and imaging, which is not restricted by associated anomalies, a thorough understanding of the cardiovascular anatomy of the situs ambiguous can be achieved using MRI, which is of considerable value in the surgical correction of this complicated anomaly. MRI can obviate or facilitate catheterization in these critically ill patients.

Abnormalities, Multiple↗
PubMedDate not supplied

Evidence for symbiont-induced alteration of a host's gene expression: irreversible loss of SAM synthetase from Amoeba proteus.

Symbiont-bearing xD amoebae no longer produce a 45-kDa cytoplasmic protein that functions as S-adenosylmethionine synthetase in symbiont-free D amoebae. The absence of the protein in xD amoebae is attributable to xD amoeba's failure to transcribe the corresponding gene as a result of harboring bacterial symbionts. However, xD amoebae have about half the level of enzyme activity found in D amoebae, indicating that they use an alternative source for the enzyme. xD amoebae originated from D amoebae by bacterial infection and now depend on their symbionts for survival. xD amoebae exhibit irreversible nucleolar abnormalities when their symbionts are removed, suggesting that X-bacteria supply the needed enzyme. A monoclonal antibody against the 45-kDa protein was produced and used as a probe in cloning its corresponding cDNA. The product of the cDNA was found to have S-adenosylmethionine synthetase activity. These results show how symbiotic X-bacteria may become essential cellular components of amoeba by supplementing a genetic defect for an amoeba's house-keeping gene that is brought about by an action of X-bacteria themselves. This is the first reported example in which symbionts alter the host's gene expression to block the production of an essential protein.

Amino Acid Sequence↗
PubMedDate not supplied

Pulmonary veins in total anomalous pulmonary venous connection with obstruction: demonstration using silicone rubber casts.

We studied the postmortem vascular anatomy of four patients with total anomalous pulmonary venous connection (TAPVC) with obstruction using a silicone rubber casting method. Two patients were studied clinically but died before therapeutic intervention, one died after corrective surgery, and another was not diagnosed before death. The morphologic types were supracardiac (2), infracardiac (1), and mixed (1). One of the supracardiac forms had a stenosis at the left vertical vein by a bronchoarterial vise, and a collateral channel to the right superior caval vein was also present. In the other supracardiac case, a left upper pulmonary vein was connected to the left vertical vein above the stenotic portion, resulting in postoperative pulmonary hemorrhage into the left upper lobe. The patient with infracardiac TAPVC had a tree-shaped descending vertical vein and small opening at the inferior caval vein. In the mixed type, a right upper pulmonary vein ran between the pulmonary artery and bronchus draining into the superior caval vein, and the rest of the drainage was to the portal vein.

Autopsy↗