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S O Choi

Publications and source records attributed to S O Choi.

At least 19 recordsLinked to original sources
PubMed2001

Cystic rectal duplication: a rare cause of neonatal bladder-outlet obstruction and hydronephrosis.

A case of cystic rectal duplication (RD) is presented. A 7-day-old female was admitted with acute urinary retention, voiding difficulty, and abdominal distention since she was 4 days of age. Ultrasound and abdominal computed tomography (CT) demonstrated a huge, cystic mass in the pelvis and abdomen that resulted in acute urinary retention and bilateral hydronephrosis. CT-guided drainage of the lesion followed by transabdominal surgical excision resulted in a cure. Pathologic examination demonstrated a RD lined by respiratory epithelium.

Cysts↗
PubMed2001

Technical innovation for noninvasive and early diagnosis of biliary atresia: the ultrasonographic "triangular cord" sign.

In this article, we introduce our experience regarding a new and noninvasive diagnostic tool, using ultrasonography, for the early and definite diagnosis of biliary atresia. We have focussed on the ultrasonographic image of the cone-shaped periportal fibrous mass in infants with biliary atresia since 1992, and have finally identified a triangular or band-like periportal echogenicity ("triangular cord" sign), mainly cranial to the portal vein. Based on our experience and other reports from Japan and Singapore, the ultrasonographic triangular cord sign is a simple, time-saving, highly reliable, and definite tool in the diagnosis of biliary atresia from infantile intrahepatic cholestasis, representing a positive predictive value greater than 95%. We have proposed a new diagnostic strategy in the evaluation of infantile cholestasis, with emphasis on the ultrasonographic triangular cord sign.

Biliary Atresia↗
PubMed2001

Choroidal tuberculoma with membranous glomerulonephritis.

We report treatment of a 24-year-old man with membranous glomerulonephritis (MGN) who developed a solitary choroidal tuberculoma in association with miliary tuberculosis during steroid therapy. In June 1995, the patient had developed nephrotic syndrome. He had refused renal biopsy at that time. So we treated him with corticosteroids having assumed a diagnosis of minimal change nephrotic syndrome. After initial corticosteroids and diuretics therapy for 5 months, his generalized edema resolved but proteinuria (3 positive) continued, suggesting the presence of other forms of glomerulonephritis. Renal biopsy performed in January 1996. The patient was diagnosed as having MGN. The patient was closely observed over a period of 34 months and remained stable without steroid therapy. However at 34 months, generalized edema was again noted and steroid therapy at high dosage was initiated. After 5 months of steroid therapy, he developed miliary tuberculosis and a solitary choroidal mass. An antituberculosis chemotherapeutic regimen was started and after a further 5 months, all clinical symptoms and signs of the pulmonary lesion were resolved and a measurable shrinking of the choroidal mass was recorded.

Adult↗
PubMed2000

Identification of active-site residues in Bradyrhizobium japonicum malonamidase E2.

Malonamidase (MA) E2 was previously purified and characterized from Bradyrhizobium japonicum USDA 110. The gene encoding this enzyme has been cloned, sequenced and expressed in Escherichia coli. The recombinant MAE2 was purified to homogeneity from the transformed E. coli. The biochemical properties of the recombinant enzyme are essentially identical to those from wild-type B. japonicum. A database search showed that the MAE2 protein has a high sequence similarity with the common signature sequences of the amidase family. The only exception is that the aspartic residue in these signature sequences is replaced by a glutamine residue. In order to identify amino acid residues essential for enzyme activity, a series of site-directed mutagenesis studies and steady-state kinetic experiments were performed. Gln(195), Ser(199), Cys(207) and Lys(213) of the common signature sequences were selected for site-directed mutagenesis. Among the mutants, Q195D, Q195E and S199C showed less than 0.02% of the k(cat) value of the wild-type enzyme, and S199A, Q195L and Q195N exhibited no detectable catalytic activities. Mutants (K213L, K213R and K213H) obtained by replacement of the only conserved basic residue, Lys(213), in the signature sequences, also displayed significant reductions (approx. 380-fold) in k(cat) value, whereas C207A kept full activity. These results suggest that MAE2 may catalyse hydrolysis of malonamate by a novel catalytic mechanism, in which Gln(195), Ser(199) and Lys(213) are involved.

Amidohydrolases↗
PubMed2000

Stereoselective determination of cetirizine and studies on pharmacokinetics in rat plasma.

Enantiomers may confer benefits over racemates in therapeutic uses and we developed a chiral separation method of cetirizine enantiomers, a second generation H1 histamine receptor antagonist, in rat plasma. alpha1-Acidglycoprotein based chiral stationary phase(AGP-CSP), monitored with UV at 230 nm was used to separate the enantiomers. Observed enantioselectivity (alpha) was 2.0. The AGP-CSP was also used at a preparative scale to isolate the enantiomers with an optical purity of greater than ee 99%. In addition, an analysis was carried out for the cetirizine enantiomers in rat plasma to study the differences of enantiomers in pharmacokinetics. Both (+)- and (-)-cetirizine were separated using a reversed-phase column of AGP, and were detected at the range of 2.5-200 microg ml(-1) in plasma. Although there was no recognizable differences in pharmacokinetics between the enantiomers in rat, the method appears to be useful for their pharmacokinetic studies.

Animals↗
PubMed2000

Enantioselective determination of cetirizine in human urine by HPLC.

In order to study the simultaneous determination of (+)- and (-)-cetirizine in human urine we have developed a chiral separation method by HPLC. A chiral stationary phase of alpha1-acidglycoprotein, the AGP-CSP, was used to separate the enantiomers. The pH of the phosphate buffer, as well as the content of the organic modifier in the mobile phase, markedly affected the chromatographic separation of (+)- and (-)-cetirizine. A mobile phase of 10 mmol/l phosphate buffer (pH 7.0)-acetonitrile (95: 5, v/v) was used for the urine assays. Ultraviolet absorption was monitored at 230 nm and roxatidine was employed as the internal standard for quantification. (+)-Cetirizine, (-)-cetirizine and the internal standard were eluted at retention times of 12, 16, and 32 mins, respectively. The detection limit for cetirizine enantiomers was 400 ng/ml of urine. A pharmacokinetic study was conducted with the help of 5 healthy female volunteers who were administered with a single oral dose of racemic cetirizine (20 mg). The peak area ratios provided by the cetirizine enantiomers were linear (r>0.997) over a concentration range of 2.5-200 microg/ml. The peak of the excreted cetirizine enantiomers appeared in the urine sample during the period of 1-2 hrs following the administration of the oral dose. The excreted level of (+)-cetirizine was slightly higher than (-)-cetirizine but the difference was not statistically significant. However, this method appears to have applications for enantioselective pharmacokinetic studies of racemic drugs.

Adult↗
PubMed2000

A case of membranoproliferative glomerulonephritis associated with a hydatidiform mole.

We treated a 54-year-old woman who was suffering from membranoproliferative glomerulonephritis associated with a complete type of hydatidiform mole. The renal manifestations were proteinuria and hematuria. A renal biopsy, performed before gynecologic management, disclosed focal and segmental subendothelial deposits with a proliferation of the mesangial cell and showed irregularly thickened capillary loops by light and electronmicroscoy. Genralized edema, proteinuria and hematuria were completely recovered by suction and curettage of the hydatidiform mole with prophylactic chemotherapy. The clinical manifestation of earlier presented 3 cases have been the nephrotic syndrome. The common feature of them was a complete remission of the nephropathy after the removal of the hydatidiform mole. The relationship between the hydatidiform mole and glomerulonephritis remains unresolved at present. But we concluded that the hydatidiform mole might be a cause of glomerulonephritis in this case.

Diagnosis, Differential↗
PubMed1999

The ultrasonographic 'triangular cord' coupled with gallbladder images in the diagnostic prediction of biliary atresia from infantile intrahepatic cholestasis.

PURPOSE: The aim of this study was to evaluate the importance of the ultrasonographic "triangular cord" (TC) coupled with gallbladder images in the diagnostic prediction of biliary atresia (BA) from infantile intrahepatic cholestasis. METHODS: Seventy-nine infants with cholestatic jaundice underwent ultrasound examinations, focusing on the TC and gallbladder images. The TC was defined as visualization of a triangular or bandlike periportal echogenicity (3 mm or greater in thickness), which represents a cone-shaped fibrotic mass cranial to the portal vein in infants with BA. An abnormal gallbladder (nonvisualized or small) was thought to be more suggestive of BA than infantile intrahepatic cholestasis. RESULTS: Among 25 infants with BA, 21 showed TC, whereas 4 had no TC. Fifty-three of 54 infants with infantile intrahepatic cholestasis had no TC, showing a diagnostic accuracy of 94% with 84% sensitivity and 98% specificity. As for positive predictive value in the diagnosis of BA by the TC coupled with gallbladder images, it was 100% when a positive TC was coupled with an abnormal gallbladder and 88% when a positive TC was coupled with a normal gallbladder. It decreased to 25% when a negative TC was coupled with an abnormal gallbladder. CONCLUSIONS: The TC appears to be a very specific and definite ultrasonographic finding in the early diagnosis of BA. Positive TC regardless of gallbladder images is highly suggestive of BA, showing a 95% positive predictive value, but BA cannot be ruled out when negative TC is coupled with an abnormal gallbladder, requiring further diagnostic modalities such as liver needle biopsy or hepatobiliary scintigraphy.

Bile Ducts, Extrahepatic↗
PubMed1999

Immunoglobulin A nephropathy in patients with non-insulin dependent diabetes mellitus.

The occurrence of immunoglobulin A nephropathy (IgAN) in patients with noninsulin dependent diabetes mellitus (NIDDM) is a rare event and of pathogenetic interest. It is not clear whether this is merely coincidence. We report here five patients with IgAN in NIDDM associated with or without diabetic glomerulosclerosis. All of the patients were Korean males. In three patients, diabetes mellitus was diagnosed at the same time with diagnosis of IgAN, and the known duration of the diabetes in the other two patients were three and seven years, respectively. There was no evidence of diabetic retinopathy in four patients, but it was found in one patient. In all cases, the diagnosis of IgAN was made by immunohistology.

Adult↗
PubMed1999

Environmental controls in reducing house dust mites and nasal symptoms in patients with allergic rhinitis.

A randomized comparison group pretest-posttest experimental design was used to quantitatively determine the effects of environmental control measures on patients with allergic rhinitis. Environmental controls included wrapping the mattress with a vinyl cover, washing the top bedding cover with 55 degrees C hot water every two weeks, removal of soft furniture, and wet cleaning of the bedroom floor every day. Thirty subjects were randomly assigned to experimental and control groups. The amount of house dust mites in dust samples collected from the bedroom floor, bedding and mattress, as well as the nasal symptoms of patients, were measured twice at one-month intervals. A significant decrease in house dust mites in dust samples and relief in patients' nasal symptoms were observed in the experimental group who had environmental controls.

Adult↗
PubMed1999

Non-diabetic renal disease in patients with non-insulin dependent diabetes mellitus.

The diagnosis of diabetic nephropathy (DN) is almost always based on clinical grounds. The diagnosis is supported by a long history of diabetes, evidence of target organ damage and proteinuria preceding azotemia. The validity of this clinical approach is well established in insulin dependent diabetes mellitus but not in non-insulin dependent diabetes mellitus (NIDDM). It is thus important to determine which patients with NIDDM accompanied by non-diabetic renal disease (NDRD) should have a biopsy. However, factors clinically associated with NDRD in patients with NIDDM remain unclear. Therefore we reviewed clinical data, laboratory data and renal biopsies from 22 NIDDM patients who underwent renal biopsy between 1992 and 1998 in Wonju Christian Hospital. From this data, we identified important features that would discriminate between DN and NDRD. There were 8 women and 14 men. Age ranged from 33 to 68 (51.2 +/- 10.7) years. The duration of diabetes at biopsy ranged from 0 to 13 (4.2 +/- 4.2) years. Nephrotic syndrome was present in 13 patients. The patients with NDRD (n = 14) and DN (n = 8) had comparable 24-hour proteinuria, 24-hour albuminuria, creatinine clearance, serum creatinine, albumin, as well as incidences of neuropathy and hypertension. The significant factors that predict the NDRD included a short duration of the diabetes mellitus, the presence of dysmorphic red blood cells in urine, the absence of retinopathy and HbA1c below 9% (p < 0.05, respectively). NDRD included IgA nephropathy (n = 6), minimal change disease (n = 3), membranous nephropathy (n = 3), membranous lupus nephritis (n = 1) and acute interstitial nephritis (n = 1). Multiple logistic regression analysis revealed that the short duration of DM and the absence of retinopathy were factors significantly associated with NDRD. In summary, when there is a short duration of diabetes mellitus, or an absence of retinopathy seen in patients with NIDDM, then renal biopsy in diabetic patients aids in the detection of NDRD.

Adult↗
PubMed1999

Do dialysis patients need extra folate supplementation?

To assess folate status and to evaluate the need for conventional folate supplementation in patients on dialysis, we measured serum folate, vitamin B12, and red cell folate concentrations by radioimmunoassay. Thirty-four continuous ambulatory peritoneal dialysis (CAPD) patients and 60 hemodialysis (HD) patients who had not been supplemented with folate were enrolled. Serum folate levels (5.8 +/- 3.6 ng/mL vs 2.0 +/- 1.1 ng/mL, p < 0.001) and vitamin B12 levels (831.4 +/- 416.9 pg/mL vs 513.9 +/- 213.3 pg/mL, p < 0.001) were significantly higher in CAPD patients than HD patients. The red cell folate levels (849.7 +/- 489.4 ng/mL vs 491.0 +/- 253.2 ng/mL, p < 0.001) were also significantly higher in CAPD patients. The incidences of folate deficiency in CAPD and HD patients were overestimated using the cut-off value for serum folate concentration (3.0% vs 71.7%, respectively), but the incidence of true folate deficiency was lower using the cut-off value for red cell folate level (0.0% vs 10.0%, respectively). In conclusion, the true incidence of folate deficiency in stable CAPD and HD patients is surprisingly low, even in patients who may not be taking folate supplements. The need for conventional folate supplementation in patients with end-stage renal disease on dialysis must therefore be re-evaluated. Before the decision is made to use folate supplementation, measurement of red cell folate is essential to assess of folate reserves of the patients on dialysis.

Adult↗
PubMed1998

Ultrasonographic "triangular cord": the most definitive finding for noninvasive diagnosis of extrahepatic biliary atresia.

Early diagnosis of extrahepatic biliary atresia (EHBA) is very important for a successful bile drainage procedure. An urgent and extensive investigation is warranted to make a differential diagnosis of EHBA from other cholestatic disease, especially neonatal hepatitis (NH). The diagnosis may be made by laparotomy with cholangiogram and liver biopsy but these procedure are invasive. Because a cone-shaped fibrous tissue was always found at the porta hepatis during Kasai's procedure and that type of fibrous tissue has never been seen in other types of cholestatic jaundice, the authors have used ultrasonography (US) to detect fibrous remnants at the porta hepatis in infants clinically suspected of having EHBA and identified a triangular- or tubular-shaped echogenic density in the bifurcation of the portal vein at the porta hepatis in EHBA and called it an ultrasonographic "triangular cord (TC)". The authors determined that the presence of TC denoted the EHBA. On the other hand, nonvisualization of TC was interpreted as consistent with NH. In the present study, the authors reviewed ultrasonographic examination and hepatobiliary scintigraphy in a series of 41 infants suspected of having EHBA or NH. The TC was identified in thirteen infants. In twelve of thirteen infants with TC found by US, the diagnosis of EHBA was confirmed at the time of Kasai's Roux-en-Y hepatoportojejunostomy operation. The remaining one died at 15 months of age without having treatment. TC was not visualized in 28 infants. Twenty-seven of 28 infants with absent TC improved clinically through medical treatment for NH. The other, diagnosed to have NH by needle and wedge liver biopsies, eventually showed a TC on follow-up US examination performed 40 days after the initial examinations. Moreover, follow-up percutaneous liver biopsy specimen showed typical findings of biliary atresia with bile duct proliferation and portal fibrosis. The patient underwent a Kasai hepatoportoenterostomy. On review of the hepatobiliary scintigraphy, all 13 infants with TC had no intestinal excretion of isotope. Thirteen of 28 infants (46%) without TC also had no intestinal excretion of isotope in the 24hour follow-up but all of them were confirmed to have NH by percutaneous liver biopsy and their subsequent clinical course confirmed NH with the detection of bile in their stool except one. On the basis of these results, the authors conclude that ultrasonographic TC is a very specific finding representing the fibrous cone at the porta hepatis and is a quick, simple, and definitive tool in the noninvasive diagnosis of EHBA. If TC is visualized, no further studies are necessary and exploratory-laparotomy can be done. If TC is not visualized, hepatobiliary scintigraphy is recommended to demonstrate bile duct patency. Percutaneous liver biopsy is only required if neither TC nor intestinal excretion of isotope is seen. However, early exploration or close US follow-up study is recommended in any patient suspected of having EHBA clinically, even if liver biopsy confirms the presence of NH.

Algorithms↗
PubMed1997

A new diagnostic approach to biliary atresia with emphasis on the ultrasonographic triangular cord sign: comparison of ultrasonography, hepatobiliary scintigraphy, and liver needle biopsy in the evaluation of infantile cholestasis.

BACKGROUND/PURPOSE: The authors evaluated prospectively the utility of ultrasonography, Tc-99m-DISIDA hepatobiliary scintigraphy, and liver needle biopsy in differentiating biliary atresia (BA) from intrahepatic cholestasis in 73 consecutive infants who had cholestasis. METHODS: Sixty three ultrasonographic examinations of 61 infants with 7.0-MHz transducer were carried out, focusing on the fibrous tissue at the porta hepatis. The authors defined the triangular cord (TC) as visualization of a triangular or tubular shaped echogenic density just cranial to the portal vein bifurcation on a transverse or longitudinal scan. RESULTS: Although 17 of 20 ultrasonographic examinations from infants who had BA denoted TC, 43 ultrasonographic examinations from infants with either neonatal hepatitis (NH) or other causes of cholestasis denoted no TC, showing a diagnostic accuracy of 95% with 85% sensitivity and 100% specificity. Investigation with Tc-99m-DISIDA hepatobiliary scintigraphy showed that 24 of 25 infants who had BA had no gut excretion, and 16 of 46 infants who had either NH or other causes of cholestasis had gut excretion, showing a diagnostic accuracy of 56% with 96% sensitivity and 35% specificity. Therefore, gut excretion of tracer excluded BA, but no gut excretion of tracer needed further investigations as liver needle biopsy. Forty-four liver needle biopsies were carried out in 19 infants who had BA and 24 infants who had either NH or other causes of cholestasis. Although 18 of 20 biopsy findings in infants who had BA were correctly interpreted as having BA, 23 of 24 biopsy results in infants who had either NH or other causes of cholestasis were correctly diagnosed, showing a diagnostic accuracy of 93% with 90% sensitivity and 96% specificity. CONCLUSIONS: Since the introduction of ultrasonographic TC sign in the diagnosis of BA by our institution, we have found that it seemed to be a simple, time-saving, highly reliable, and non-invasive tool in the diagnosis of BA from other causes of cholestasis. The authors propose a new diagnostic strategy in the evaluation of infantile cholestasis with emphasis on ultrasonographic TC sign as first priority of investigations. When the TC is visualized, prompt exploratory laparotomy is mandatory without further investigations. When the TC is not visualized, hepatobiliary scintigraphy is the next step. Excretion of tracer into the small bowel actually rules out BA. Liver needle biopsy is reserved only for the infants with no excretion of tracer. The authors believe that a correct decision regarding the need for surgery can be made in almost all cases with infantile cholestasis by this multidisciplinary approach.

Algorithms↗
PubMed1996

'Triangular cord': a sonographic finding applicable in the diagnosis of biliary atresia.

Biliary atresia (BA) is characterized by luminal obstruction of the extrahepatic bile duct with fibrous remnants. The authors reviewed ultrasonographic examinations of the fibrous tissue in the bifurcation of the portal vein at the porta hepatis and identified the triangular- or tubular-shaped echogenic density, the so-called "triangular cord" (TC), in the vicinity of the portal vein on a transverse or longitudinal scan. In this prospective study, the authors investigated whether TC was useful in the noninvasive diagnosis of biliary atresia in 18 infants who had persistent neonatal jaundice. This was done by comparing the ultrasonographic examination with the histopathologic examination (HPE) of liver specimens obtained from a needle biopsy. The TC was identified in nine patients, all of whom were confirmed to have BA by HPE. The TC was not observed in the other nine patients, who had neonatal hepatitis (NH). The mean size of the TC was 13 mm (wide) x 6 mm (thick) (width range, 5 to 21 mm; thickness range, 4 to 12 mm). The diagnosis of BA was confirmed at the time of Kasai hepatoportojejunostomy in eight of the nine patients whose TC was noted by ultrasonography (US). The other patient was discharged because his parents refused the operation; he died of liver failure at 15 months of age. The nine patients with absent TC were treated medically for NH. Eight of them improved clinically. The other, diagnosed to have NH by needle and wedge liver biopsies, was reexamined 40 days after the initial examination because of worsening jaundice. A 18 x 12-mm TC was visualized ultrasonographically. Additionally, a percutaneous liver biopsy specimen showed BA with severe portal fibrosis and ductal proliferation. The patient underwent a Kasai hepatoportoenterostomy. On the basis of these results, the authors conclude that TC is a very specific ultrasonographic finding, representing the fibrous cone at the porta hepatis, and is a useful tool in the noninvasive diagnosis of BA. However, early exploration or close US follow-up is recommended for any patient suspected of having BA clinically, even if a liver biopsy confirms the NH.

Biliary Atresia↗
PubMed1996

Electron microscopic study of the liver with biliary atresia and neonatal hepatitis.

Eleven cases of biliary atresia (BA) and eight of neonatal hepatitis (NH) were studied, using transmission electron microscopy, to document their different ultrastructural characteristics and to elucidate the possible pathogenesis of biliary atresia. Among 30 consecutive liver biopsies obtained from 19 infants with BA or NH, 21 specimens composed (13 BA, 8 NH) were examined ultrastructurally. The electron microscopic features of NH (patients' age range, 35 to 60 days) were (1) giant hepatocytic transformation with scattered areas of dilated endoplasmic reticulum, indicative of intracytoplasmic degeneration, (2) frequent cytoplasmic biliary necrosis, and (3) relatively intact microvilli in most bile canaliculi, which contained some hepatocytic cytoplasmic fragments. These features strongly suggest that the main pathological process in NH is hepatocellular injury rather than bile duct damage. In contrast, all cases with BA (age range, 27 to 130 days) demonstrated (1) marked hepatocellular cholestasis associated with many lysosomes and myelin figures, (2) marked loss of bile canalicular microvilli, (3) degenerated bile ductular cells containing bile pigments, and (4) periductal inflammatory fibrosis. These features suggest that the main pathological process in BA involves the biliary system. A few viral inclusions were observed in two cases with BA, which suggests that viral infection is a potential cause. In two BA cases (aged 40 and 43 days at the time of first biopsy), the ultrastructural findings essentially were the same as those of NH, and follow-up biopsy specimens (at 48 and 94 days) showed findings consistent with BA. Such results support Landing's hypothesis that BA and NH are different manifestations of a single pathological process.

Biliary Atresia↗