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Biomedical subjects

J H Yoon

Publications and source records attributed to J H Yoon.

139 records · Page 8Linked to original sources
PubMed1992

Comparison of outcome among double, bifoil and Inoue balloon techniques for percutaneous mitral valvuloplasty in mitral stenosis.

The efficacy and complications of three different methods of percutaneous mitral valvuloplasty (PMV) were evaluated in 245 patients with mitral stenosis (MS). Eight six patients (35%) had severe MS defined in the mitral valve area (MVA) less than 1.0 cm2 (0.8 +/- 0.2) and Echoscore greater than or equal to 8(8.9 +/- 1.1). The results including post MCA greater than or equal to 1.5cm2 and complications, i.e, increment of mitral regurgitation (MR) greater than or equal to +1 and atrial septal defect (ASD) with Qp/Qs greater than or equal to 1.5 were compared in overall and in severe MS groups. There was no statistically significant difference in size of MVA before and after PMV between overall patients group and severe mitral stenosis group (0.8 +/- 0.1 vs 1.7 +/- 0.4cm2 in the double technique, 0.8 +/- 0.2 vs 1.5 +/- 0.3cm2 in the Bifoil technique and 0.7 +/- 0.2 vs 1.8 +/- 0.3cm2 in the Inoue technique. p: NS). However, a significantly larger number of patients in the severe MS group had better MVA with the double than the Bifoil technique [MVA greater than or equal to 1.5cm2; 42 (72%) vs 6 (46%), p less than 0.005] whereas higher complications were observed with the Bifoil than the Inoue technique (MR greater than or equal to +1; 9 (69%) vs 4 (27%), ASD (Qp/Qs greater than or equal to 1.5' 6 (46%) vs 2 (13%) p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Atypical clinical manifestations of amebic colitis.

Amebic colitis is a disease revealing diverse clinical manifestations and endoscopic gross features and often confused with other types of colitis. In case of misdiagnosis as an idiopathic inflammatory bowel disease or delayed recognition of intestinal amebiasis, an undesirable outcome may occur resulting from erroneous administration of steroids or delayed antiamebic treatment. To demonstrate the pitfalls in the diagnosis and treatment of intestinal amebiasis, 3 cases of amebic colitis with atypical clinical manifestations are presented in this paper. In conclusion, despite the low sensitivities of routine stool examination for parasite and histopathologic confirmation in biopsy specimen, every effort must be made to find amebic trophozoites either in fresh stool or biopsy specimens for prompt and correct diagnosis of amebic colitis when we manage patients with chronic intestinal ulcerations, even though their clinical course and endoscopic findings are not typical of amebiasis. Moreover, following initial successful anti-amebic therapy, more careful clinical, endoscopical, and parasitological follow-up should be done for the early detection of recurrence.

Adult↗
PubMed1989

A case of recurrent infantile polycystic kidney associated with hydrops fetalis.

Nonimmune hydrops fetalis is becoming a predominant form of fetal hydrops due to the declining incidence of immune hydrops fetalis triggered by Rh isoimmunization. Infantile polycystic kidney appeared to be related to hydrops fetalis whether it is causal or merely coincidental and may represent another entry to differential diagnoses. Infantile polycystic kidney was diagnosed by an elevated maternal serum alpha-fetoprotein (AFP) value coupled with an ultrasonographic abnormality scanned as a multicystic mass with ascites in the fetal abdomen antenatally. This study presents a case of infantile polycystic kidney that resulted in a stillborn baby with hydrops fetalis and extensive placental calcification; it was the first case in Korea in which nonimmune hydrops fetalis was associated with infantile polycystic kidney in consecutive siblings by autosomal recessive inheritance in one family. In addition, this paper comprehensively reviews the incidence, etiology, prenatal diagnosis and proper management of nonimmune hydrops fetalis.

Adult↗
PubMed1989

Clinical and histopathological study of fibro-osseous lesions of the jaws.

Seventy-two cases of benign fibro-osseous lesions of the jaws were reassessed, and a modified classification is proposed that may be helpful in their understanding and management. The anatomical distribution of these cases is described and compared to previously reported cases. The histogenesis of each particular lesion is also discussed. Correlative analysis of histopathologic and oral radiographic features is essential for definitive diagnosis.

Adolescent↗
PubMed1984

Relationship between polyphenol intake and blood glucose response of normal and diabetic individuals.

Five leguminous and eight nonleguminous foods were analyzed for polyphenol concentration by the Prussian Blue and the Folin Denis methods and correlated with blood glucose response (glycemic index) in normal or diabetic volunteers. Polyphenol concentrations and intakes per 50 g available carbohydrate portions were higher in the leguminous foods than those in the nonleguminous foods. In both normal and diabetic individuals, a negative correlation was observed between glycemic index and the concentration or total intake of polyphenols. Polyphenols, especially the large polymeric type or condensed tannins, appear to be responsible in part for the reduced glycemic response to carbohydrate foods and in part to lower blood glucose response to legumes compared with cereal products.

Blood Glucose↗
PubMed1983

The effect of phytic acid on in vitro rate of starch digestibility and blood glucose response.

The effect of phytic acid on starch digestibility was studied in vitro and related to the blood glucose response (glycemic index) in healthy volunteers. The glycemic index was found to correlate negatively with the phytic acid content of the food tested. In vitro digestion studies involving human saliva at physiological pH and temperature showed that in the presence of sodium phytate (equivalent to 2% phytic acid based on the starch portion), the rate of digestion of raw wheat starch was reduced significantly by 50%. This was reversed by the addition of calcium which is known to complex phytic acid. Similarly, when sodium phytate was added to unleavened bread, its digestibility was also decreased and in feeding trials high phytate bread produced a flattened blood glucose response.

Blood Glucose↗
PubMedDate not supplied

Development of three-dimensional descriptors represented by tensors: free energy of hydration density tensor.

In order to describe the degree of interaction of a molecule with its environments by descriptors, several three-dimensional descriptors have been proposed. With the physical properties calculated around a molecule, scalar, vector, and tensor (zeroth, first, and second moments) of the physical properties were calculated and were used as descriptors for calculating the similarity index between the molecules. The tensors contain the information on the spatial distribution of those physical properties around the molecule. Hydration Free Energy Density (HFED) proposed by No et al. was used to calculate HFED tensor. The descriptors were used for the similarity index calculations between substituted benzenes and between lead compounds of HIV-1 protease inhibitors. The substituted benzenes are grouped according to the similarity indices. The grouping seems reasonable from the viewpoint of a chemical sense. The lead fragments of the HIV-1 protease inhibitors have a high similarity among themselves though their chemical formulas are not very similar, the lead fragments are diverse. Although the chemical formulas are diverse, the spatial distribution of the physical properties around the molecules is similar. The descriptors have high discriminating power in the similarity calculation between the molecules.

Binding Sites↗
PubMedDate not supplied

Diffuse micronodular lung disease: HRCT and pathologic findings.

PURPOSE: The purpose of our study was to compare the findings seen on HRCT with those from pathologic examination in patients with diffuse micronodular lung disease (DMLD). METHOD: Forty consecutive patients with biopsy-proven DMLD (each nodule being <5 mm in diameter and occupying more than two-thirds of lung volume on chest radiograph) were included. High resolution CT (HRCT) scans were analyzed with particular attention to the location of nodules in and around the secondary pulmonary lobule (centrilobular, perilymphatic, and random) and the zonal distribution. The findings were compared to pathology. RESULTS: CT scans showed centrilobular nodules in the patients with diffuse panbronchiolitis (n = 4), infectious bronchiolitis [n = 4; Hemophilus influenzae (n = 3) and Mycoplasma pneumoniae (n = 1)], hypersensitivity pneumonia (n = 3), bronchogenic disseminated tuberculosis (n = 3), pneumoconiosis (n = 1), primary lymphoma of the lung (n = 1), and foreign body-induced necrotizing vasculitis (n = 1). They demonstrated perilymphatic nodules in the patients with pneumoconiosis (n = 5), sarcoidosis (n = 2), and amyloidosis (n = 2). They demonstrated micronodules of random distribution in the patients with miliary tuberculosis (n = 9) and pulmonary metastasis (n = 5). Upper and middle zonal predominance was seen in two of two patients with sarcoidosis and in two of six patients with pneumoconiosis. The CT location of nodules in the secondary pulmonary lobule represented the location and nature of the lesion on pathologic examination. CONCLUSION: By showing the distribution of micronodules in and around the secondary pulmonary lobule, HRCT enables the narrowing of the differential diagnosis of DMLD. CT findings reflect gross morphologic features of pathologic examination.

Adult↗
PubMedDate not supplied

Evaluation of tracheobronchial disease with helical CT with multiplanar and three-dimensional reconstruction: correlation with bronchoscopy.

The advantage of volumetric computed tomography in the thorax is the possibility of acquiring both multiplanar and three-dimensional (3D) images, thus enabling precise diagnosis and evaluation of extent of disease involving the airways. Multiplanar and 3D images appear to be useful for global understanding of the status of the tracheobronchial tree, particularly for evaluation of focal stenosis of the airways. Such images seem to be especially useful in evaluating the longitudinal extent of airway lesions, thus providing valuable information for preparing a road map for bronchoscopy, for surgical planning, and for follow-up of treatment response. However, multiplanar and 3D images do not appear to be useful in lesion detection or evaluation of transaxial extension. Multiplanar and 3D images also seem to be helpful in demonstrating whether a lesion is endobronchial, submucosal, or peribronchial. The quality of such images appears to be excellent or good in almost all patients.

Adult↗
PubMedDate not supplied

The use of contrast-enhanced color Doppler ultrasound in the differentiation of retinal detachment from vitreous membrane.

OBJECTIVE: To compare the clinical utility of contrast-enhanced color Doppler US in the differentiation of retinal detachment (RD) from vitreous membrane (VM) with that of various conventional US modalities, and to analyze the enhancement patterns in cases showing an enhancement effect. MATERIALS AND METHODS: In 32 eyes examined over a recent two-year period, RD (n=14) and VM (n=18) were confirmed by surgery (n=28) or clinical follow-up (n=4). In all cases, gray-scale, color Doppler, and power Doppler US were performed prior to contrast injection, and after the intravenous injection of Levovist (Schering, Berlin) by hand for 30 seconds at a dose of 2.5 g and a concentration of 300 mg/mL via an antecubital vein, contrast-enhanced color Doppler US was performed. At Doppler US, the diagnostic criterion for RD and VM was whether or not color signals were visualized in membranous structures. RESULTS: Diagnostic accuracy was 78% at gray-scale US, 81% at color Doppler US, 59% at power Doppler US, and 97% at contrast-enhanced color Doppler US. The sensitivity of color Doppler US to color signals in RD increased from 57% to 93% after contrast enhancement. The enhancement patterns observed were signal accentuation (n=3), signal extension (n=2), signal addition (n=3), and new signal visualization (n=5). CONCLUSION: Contrast-enhanced color Doppler US was the most accurate US modality for differentiating RD from VM, showing a significantly increased signal detection rate in RD.

Adolescent↗
PubMedDate not supplied

Localized proton MR spectroscopic detection of nonketotic hyperglycinemia in an infant.

Nonketotic hyperglycinemia (NKH) is a rare metabolic brain disease caused by deficient activity of the glycine cleavage system. Localized proton MR spectroscopy (echo-time 166 msec), performed in an infant with the typical clinical and biochemical features of neonatal NKH, showed a markedly increased peak intensity at 3.55 ppm, which was assigned to glycine. Serial proton MR spectroscopic studies indicated that glycine/choline and glycine/total creatine ratios correlated closely with the patient's clinical course. Proton MR spectroscopy was useful for the non-invasive detection and monitoring of cerebral glycine levels in this infant with NKH.

Humans↗
PubMedDate not supplied

Selective gene expression in hepatic tumor with trans-arterial delivery of DNA/liposome/transferrin complex.

Since hepatocellular carcinoma (HCC) is frequently presented at an advanced stage, only a small portion of patients with HCC can be treated with local modalities. Gene therapy is, therefore, one of the more promising approaches for patients with advanced HCC. To develop a new strategy for targeting gene delivery to the hepatic tumor, the efficiency of the transarterial delivery of liposome-DNA complex was evaluated in VX2 carcinoma implanted into the liver of rabbits. A mixture of pSV-beta galactosidase plasmid (40 micrograms), lipofectin (80 microliters), and transferrin (852 micrograms), the optimal proportion of which determined in vitro, was infused via the hepatic artery of a rabbit with VX2 hepatic tumors. The efficiency of trans-arterial gene delivery was compared to that of intra-tumoral injection. Rabbits (5 in each group) were sacrificed 48 hours after gene delivery and hepatic tissues were examined using X-gal staining. beta-galactosidase staining was observed exclusively within the tumor following the trans-arterial gene transfer. In contrast, adjacent peritumoral cells in addition to hepatic tumor cells were transfected by the intra-tumoral injection of transgene. These data indicate that enhanced gene expression in hepatic tumors is possible using trans-arterial delivery of the liposome-DNA complex.

Animals↗