Search PubMed⌕ Search

Biomedical subjects

M J Kim

Publications and source records attributed to M J Kim.

At least 127 records · Page 7Linked to original sources
PubMed2000

Oxidation of arsenite in groundwater using ozone and oxygen.

Oxidation of arsenite [As(III)] with ozone and oxygen was investigated in groundwater samples containing 46-62 micrograms/l total dissolved arsenic, 100-1130 micrograms/l Fe and 9-16 micrograms/l Mn. Conversion of As(III), which constituted over 70% of dissolved arsenic in the samples, to As(V) was fast with ozone, but sluggish with pure oxygen and air. Iron and manganese in the samples were also oxidized and, by sequestering the resultant As(V), played a significant role in the rate of reaction. Sorption capacity of freshly precipitated Fe(OH)3 was estimated to be 15.3 mg As/g. The kinetics of As(III) oxidation were interpreted using modified pseudo-first-order reaction. Half-lives of As(III) in experimental solutions involving saturation with each gas were approximately 4 min for the ozone reaction and, depending on the Fe concentrations, 2-5 days for pure oxygen and 4-9 days for air.

Arsenites↗
PubMed2000

Modulation of lysophosphatidic acid-induced Cl- currents by protein kinases A and C in the Xenopus oocyte.

The roles of protein kinase C (PKC) and protein kinase A (PKA) in the regulation of lysophosphatidic acid (LPA)-induced Cl- currents in Xenopus oocytes were examined. PKC activation by phorbol 12-myristate 13-acetate (PMA) treatment completely blocked LPA-induced Cl- currents by inhibiting inositol 1,4,5-trisphosphate (IP3) elevation. This inhibitory effect of PMA on the LPA response was blocked by pretreatment of oocytes with staurosporine and 3-[N-(dimethylamino)propyl-3-indiolyll-4-[3-indolyl]maleimide (GF109203X), PKC inhibitors. In addition, treatment of oocytes with GF109203X enhanced the LPA response by increasing IP3 production. Elevation of the intracellular adenosine 3',5'-cyclic monophosphate (cAMP) concentration by treating oocytes with either forskolin (FK) plus isobutylmethylxanthine (IBMX) or 2'-O-dibutyryl-cAMP (dB-cAMP) reduced LPA-induced Cl- currents. The effect of activation of the cAMP pathway appears to be mediated by PKA, since treatment of oocytes with FK plus IBMX or dB-cAMP enhanced PKA activity. Furthermore, the inhibitory effect of dB-cAMP on the LPA response was blocked by treatment of oocytes with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulframide-2 HCl (H-89), a selective inhibitor of PKA. Both FK plus IBMX and dB-cAMP treatment reduced IP3 generation in response to LPA stimulation. Inhibition of PKA activity with H-89 or Rp-cyclic 3',5'-hydrogen phosphorothioate adenosine triethylammonium had no effect on LPA-induced Cl- currents. Finally, inhibition of the LPA response by activation of PKA was independent of extracellular Ca2+. These results demonstrate that both PKC and PKA play active roles in modulating the LPA-induced signaling pathway.

Animals↗
PubMed2000

Kinetics and inhibition of cyclomaltodextrinase from alkalophilic Bacillus sp. I-5.

The cyclomaltodextrinase from alkalophilic Bacillus sp. I-5 (CDase I-5) was expressed in Escherichia coli and the purified enzyme was used for characterization of the enzyme action. The hydrolysis products were monitored by both HPLC and high-performance ion chromatography analysis that enable the kinetic analysis of the cyclomaltodextrin (CD)-degrading reaction. Analysis of the kinetics of cyclomaltodextrin hydrolysis by CDase I-5 indicated that ring-opening of the cyclomaltodextrin was the major limiting step and that CDase I-5 preferentially degraded the linear maltodextrin chain by removing the maltose unit. The substrate binding affinity of the enzyme was almost same for those of cyclomaltodextrins while the rate of ring-opening was the fastest for cyclomaltoheptaose. Acarbose and methyl 6-amino-6-deoxy-alpha-d-glucopyranoside were relatively strong competitive inhibitors with K(i) values of 1.24 x 10(-3) and 8.44 x 10(-1) mM, respectively. Both inhibitors are likely to inhibit the ring-opening step of the CD degradation reaction.

Acarbose↗
PubMed2000

Structure of the asparagine-linked sugar chains of porcine kidney and human urine cerebroside sulfate activator protein.

The specific sugar residues and their linkages in the oligosaccharides from pig kidney and human urine cerebroside sulfate activator proteins (saposin B), although previously hypothesized, have been unambiguously characterized. Exhaustive sequential exoglycosidase digestion of the trimethyl-p-aminophenyl derivatives, followed by either matrix-assisted laser desorption/ionization and/or mass spectrometry, was used to define the residues and their linkages. The oligosaccharides were enzymatically released from the proteins by treatment with peptidyl-N-glycosidase F and separated from the proteins by reversed-phase high-performance liquid chromatography (HPLC). Reducing termini were converted to the trimethyl-p-aminophenyl derivative and the samples were further purified by normal-phase HPLC. The derivatized carbohydrates were then treated sequentially with a series of exoglycosidases of defined specificity, and the products of each digestion were examined by mass spectrometry. The pentasaccharides from pig kidney and human urine protein were shown to be of the asparagine-linked complex type composed of mannose-alpha 1-6-mannose-beta 1-4-N-acetylglucosamine-N-acetylglucosamine(alpha 1-6-fucose). This highly degraded structure probably represents the final product of intra-lysosomal exoglycosidase digestion. Oligosaccharide sequencing by specific exoglycosidase degradation coupled with mass spectrometry is more rapid than conventional oligosaccharide sequencing. The procedures developed will be useful for sequencing other oligosaccharides including those from other members of the lipid-binding protein class to which cerebroside sulfate activator belongs. (c) 2000 John Wiley & Sons, Ltd.

Animals↗
PubMed2000

Evaluation of ictal brain SPET using statistical parametric mapping in temporal lobe epilepsy.

An automated voxel-based analysis of brain images using statistical parametric mapping (SPM) is accepted as a standard approach in the analysis of activation studies in positron emission tomography and functional magnetic resonance imaging. This study aimed to investigate whether or not SPM would increase the diagnostic yield of ictal brain single-photon emission tomography (SPET) in temporal lobe epilepsy (TLE). Twenty-one patients (age 27.14 +/- 5.79 years) with temporal lobe epilepsy (right in 8, left in 13) who had a successful seizure outcome after surgery and nine normal subjects were included in the study. The data of ictal and interictal brain SPET of the patients and baseline SPET of the normal control group were analysed using SPM96 software. The t statistic SPM¿t¿ was transformed to SPM¿Z¿ with various thresholds of P<0.05, 0.005 and 0.001, and corrected extent threshold P value of 0.05. The SPM data were compared with the conventional ictal and interictal subtraction method. On group comparison, ictal SPET showed increased uptake within the epileptogenic mesial temporal lobe. On single case analysis, ictal SPET images correctly lateralized the epileptogenic temporal lobe in 18 cases, falsely lateralized it in one and failed to lateralize it in two as compared with the mean image of the normal group at a significance level of P<0.05. Comparing the individual ictal images with the corresponding interictal group, 15 patients were correctly lateralized, one was falsely lateralized and four were not lateralized. At significance levels of P<0.005 and P<0.001, correct lateralization of the epileptogenic temporal lobe was achieved in 15 and 13 patients, respectively, as compared with the normal group. On the other hand, when comparison was made with the corresponding interictal group, only 7 out of 21 patients were correctly lateralized at the threshold of P<0.005 and five at P<0.001. The result of the subtraction method was close to the single case analysis on SPM at P<0.05. However, at higher thresholds (P<0.005 and 0.001) the subtraction method was comparable to the SPM results only when individual ictal images were compared with the normal control group, and not when comparison was with the interictal group. It is concluded that SPM is an alternative diagnostic method for the localization or lateralization of the seizure focus in temporal lobe epilepsy and that interictal SPET could be omitted if a normal brain SPET database were to be established. The medical cost of seizure localization would thereby be reduced.

Adolescent↗
PubMed2000

Preoperative staging of rectal cancer with MRI: accuracy and clinical usefulness.

BACKGROUND: Preoperative staging is essential for planning of optimal therapy for patients with rectal cancer. Recently, magnetic resonance imaging (MRI) is used frequently because of its benefits of clear pelvic image are better than other diagnostic methods. The purpose of this study was to determine accuracy rates and clinical usefulness of MRI in preoperative staging of rectal cancer. METHODS: Between February, 1997, and December, 1999, 217 patients with histologically proven rectal cancer were staged preoperatively and had surgical resections performed. MRI criteria for depth of invasion was determined by the degree of disruption of the rectal wall. Metastatic perirectal lymph nodes were considered to be present if they showed heterogenous texture, irregular margin, and enlargement (>10 mm). RESULTS: The accuracy of the MRI for determining depth of invasion was 176/217 (81%) and regional lymph node invasion was 110/217 (63%). In the T stage, accuracy rate of T1 was 3/4 (75%), T2 was 20/37 (54%), T3 was 141/162 (87%), and T4 was 12/14 (86%), respectively. The specificity of lymph node invasion was 45/110 (41%) and the sensitivity was 91/107 (85%). The accuracy rate of regional lymph node involvement was 136/217 (63%). T1 and T2 were overstaged in 1/4 (25%) and 17/37 (46%), respectively, and T3 was understaged in 15/162 (9.2%). The accuracy rate to detect metastatic lateral pelvic lymph node was 4/14 (29%) after lateral pelvic lymph node dissection was done in 14 patients under MRI. The accuracy rate in assessing levator ani muscle tumor involvement was 8/11 (72%). CONCLUSIONS: MRI showed a good, comparable accuracy rate for determining depth of tumor invasion, compared with transrectal ultrasonography, which still has a low accuracy rate for detecting metastatic lymph node. MRI with endorectal coil may increase the accuracy rate of T1 and T2 lesions. In addition, clear sagittal and coronal sectional pelvic images can give a lot of information about adjacent organ invasion or any invasion of levator ani muscle. MRI can be useful for choosing an appropriate extent of lymph node dissection and type of surgery.

Adult↗
PubMed2000

Differential stereoselectivity of D- and L-myo-inositol 1,2,4, 5-tetrakisphosphate binding to the inositol 1,4,5-trisphosphate receptor and 3-kinase.

D- and L-myo-inositol 1,2,4,5-tetrakisphosphate (Ins(1,2,4,5)P(4)) were investigated for their ability to bind to the D-myo-inositol 1, 4,5-trisphosphate (Ins(1,4,5)P(3)) receptor in a bovine adrenal cortical membrane fraction, to mobilize intracellular Ca(2+) stores in Xenopus oocytes, and to bind to the rat brain Ins(1,4,5)P(3) 3-kinase overexpressed and purified in E. coli. In competitive binding experiments with the Ins(1,4,5)P(3) receptor, D-Ins(1,2,4, 5)P(4) effectively displaced [(3)H]Ins(1,4,5)P(3) in a concentration-dependent manner with a potency comparable to that of D-Ins(1,4,5)P(3), while L-Ins(1,2,4,5)P(4) was approximately 50-fold less effective than D-Ins(1,4,5)P(3) and D-Ins(1,2,4,5)P(4). The DL-Ins(1,2,4,5)P(4) racemate bound to the Ins(1,4,5)P(3) receptor with an apparent intermediate efficiency. Injection of D-Ins(1,2,4, 5)P(4) into oocytes evoked a chloride current dependent on intracellular Ca(2+) mobilization in which the agonists ranked in a similar order of potency as in the Ins(1,4,5)P(3) receptor binding. On the other hand, D-Ins(1,2,4,5)P(4) only inhibited the binding of [(3)H]Ins(1,4,5)P(3) to 3-kinase very weakly with a markedly reduced potency compared to D-Ins(1,4,5)P(3), indicating that D-Ins(1,2,4, 5)P(4) is not an effective competitor in the phosphorylation of [(3)H]-Ins(1,4,5)P(3) by 3-kinase. The results, therefore, clearly indicate that D-Ins(1,2,4,5)P(4) is as effective as D-Ins(1,4,5)P(3) in the binding to the receptor but not 3-kinase, and access of Ins(1, 2,4,5)P(4) over the Ins(1,4,5)P(3) receptor calls for stringent stereospecificity with D-Ins(1,2,4,5)P(4) being the active form in DL-Ins(1,2,4,5)P(4)-mediated Ca(2+) mobilization.

Animals↗
PubMed2000

The effect of antagonists selective for mu- and delta-opioid receptor subtypes on alcohol consumption in C57BL/6 mice.

Several studies have demonstrated that non-selective opioid receptor antagonists effectively reduce alcohol consumption in both animal models and at the clinical level. However, research examining the contribution of specific opioid receptor subtypes to this effect has yielded conflicting results. Some of these studies have shown that the effect is contingent upon the action of mu receptors while others have suggested that delta receptors are primarily responsible. The data reported here re-examine this question using the alcohol-preferring C57BL/6 mice. The results of this experiment demonstrate that D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) (CTOP), a mu-selective antagonist, and naltrindole, a delta-selective antagonist, are equally effective at reducing alcohol consumption in a limited access model compared to a saline control group. While there was no specific comparison of the effects of these drugs on alternative appetitive behavior, neither of these drugs had effects on measured off-session food or water consumption. The results of this experiment suggest that alcohol consumption is mediated by both mu- and delta-opioid receptor subtypes.

Alcohol Drinking↗
PubMed2000

Transglycosylation of neohesperidin dihydrochalcone by Bacillus stearothermophilus maltogenic amylase.

Neohesperidin dihydrochalcone (NHDC), a sweet compound derived from citrus fruits, was modified to a series of its oligosaccharides by transglycosylation activity of Bacillus stearothermophilus maltogenic amylase (BSMA). Maltotriose as a donor was reacted with NHDC as an acceptor to glycosylate for the purpose of increasing the solubility of NHDC. Maltosyl-NHDC was a major transglycosylation product among the several transfer products by TLC analysis. The structure of the major transglycosylation product was determined to be maltosyl-alpha-(1,6)-neohesperidin dihydrochalcone by MALDI-TOF/MS and (1)H and (13)C NMR. Maltosyl-NHDC was 700 times more soluble in water and 7 times less sweet than NHDC.

Chalcone↗
PubMed2000

Identification and sequencing of pineal-specific enhancing region in the mouse tryptophan hydroxylase promoter.

Pineal-specific expression of the tryptophan hydroxylase (TPH) gene has been demonstrated by a number of studies. However, little is known about the regulatory mechanism for pineal-specific expression of the TPH gene. To identify the cis-acting region responsible for pineal-specific expression of the TPH gene, we investigated a 6.1-kb 5'-flanking region of the mouse TPH gene using an immortalized pineal cell line (PGT-beta) derived from transgenic mice. By deletion analysis, it was demonstrated that the pineal-specific enhancing region resides approximately between -6.1 and -4.7 kb upstream from the transcription initiation site of the mouse TPH gene. Additionally, nucleotide sequence analysis of this region showed that the (AC/TG)22 repetitive sequence is located approximately -5.78 kb upstream of the mouse TPH gene, and several known tissue-specific cis-acting elements, such as Pit-1 and the pituitary specific element (PSE), have also been identified in the region. We believe that the analysis of the sequence and several cis-acting elements in the pineal-specific enhancing region of the mouse TPH promoter would enhance our understanding of the precise mechanism of pineal-specific expression.

Animals↗
PubMed2000

The role of specific retinoid receptors in sebocyte growth and differentiation in culture.

Retinoic acid derivatives (retinoids) exert their pleiotropic effects on cell development through specific nuclear receptors, the retinoic acid receptors and retinoid X receptors. Despite recent progress in understanding the cellular and molecular mechanisms of retinoid activity, it is unknown which of the retinoid receptor pathways are involved in the specific processes of sebocyte growth and development. In this study, we investigated the roles of specific retinoid receptors in sebocyte growth and differentiation, by testing the effects of selective retinoic acid receptor and retinoid X receptor ligands at concentrations between 10-10 M and 10-6 M in a primary rat preputial cell monolayer culture system. Cell growth was determined by number of cells and colonies, and cell differentiation by analysis of lipid-forming colonies. All-trans retinoic acid and selective retinoic acid receptor agonists (CD271 = adapalene, an RAR-beta,gamma agonist; CD2043 = retinoic acid receptor pan-agonist; and CD336 = Am580, an RAR-alpha agonist) caused significant decreases in numbers of cells, colonies, and lipid-forming colonies, but with an exception at high doses of all-trans retinoic acid (10-6 M), with which only a small number of colonies grew but they became twice as differentiated as controls (42.2 +/- 4.0% vs 22.6 +/- 2.7%, mean +/- SEM, lipid-forming colonies, p < 0.01). Furthermore, the RAR-beta,gamma antagonist CD2665 antagonized the suppressive effects of all-trans retinoic acid, adapalene, and CD2043 on both cell growth and differentiation. In contrast, the retinoid X receptor agonist CD2809 increased cell growth slightly and lipid-forming colonies dramatically in a clear dose-related manner to a maximum of 73.7% +/- 6.7% at 10-6 M (p < 0. 001). Our data suggest that retinoic acid receptors and retinoid X receptors differ in their roles in sebocyte growth and differentiation: (i) retinoic acid receptors, especially the beta and/or gamma subtypes, mediate both the antiproliferative and antidifferentiative effects of retinoids; (ii) retinoid X receptors mediate prominent differentiative and weak proliferative effects; (iii) the antiproliferative and antidifferentiative effects of all-trans retinoic acid are probably mediated by retinoic acid receptors, whereas its differentiative effect at high dose may be mediated by retinoid X receptors via all-trans retinoic acid metabolism to 9-cis retinoic acid, the natural ligand of retinoid X receptors.

Adapalene↗
PubMed2000

Effect of dialysis modalities on gastric myoelectrical activity in end-stage renal disease patients.

Gastric motility is controlled by gastric myoelectrical activity, which propagates from the proximal body to the distal antrum at a frequency of 3 cycles/min. In uremic patients, dyspeptic symptoms are common. To investigate whether dialysis modality affects gastric myoelectrical activity in uremic patients, we performed electrogastrography (EGG) in 41 patients without diabetes with end-stage renal disease (ESRD) undergoing hemodialysis (HD; n = 22) and continuous ambulatory peritoneal dialysis (CAPD; n = 19). EGG was performed noninvasively using abdominal surface electrodes in the fasting state before and 4 hours after HD and at empty and 2 hours after CAPD with 2,000 mL of dialysate. There were no significant differences in age, sex, body weight, duration of dialysis, and percentage of patients with upper gastrointestinal (UGI) symptoms (63.6% versus 42.1%). CAPD patients had significantly lower serum albumin levels (3.4 +/- 0.4 versus 3.9 +/- 0.4 g/dL; P < 0.05), greater serum total-cholesterol levels (189 +/- 33 versus 157 +/- 36 mg/dL; P: < 0.05), and greater percentages of patient with early satiety (42.1% versus 13.6%; P < 0.05) than HD patients. Dominant power significantly increased after HD (251.3 +/- 157.5 versus 512.9 +/- 390.0 dB; P < 0.05) but seemed to decrease after CAPD without statistical significance (416.2 +/- 323.6 versus 283.8 +/- 280.7 dB). There was no difference in the normal slow-wave frequency (NSWF) between HD and CAPD patients (predialysis, 60.7% +/- 29.3% versus 52.2% +/- 36.7%; postdialysis, 56.3% +/- 32.0% versus 50.9% +/- 34.2%). Tachygastria significantly increased after CAPD (pre-CAPD, 2.35% +/- 4.3% versus post-CAPD, 10.0% +/- 14.8%; P < 0.05). There was a significant correlation between changes in tachygastria after CAPD and grade of early satiety in CAPD patients with UGI symptoms (r = 0.74; P: < 0.05). Changes in NSWF after CAPD significantly correlated with age (r = -0.51; P: < 0.05). In conclusion, dialysis modalities seem to have different effects on gastric myoelectrical activity in patients with ESRD.

Female↗
PubMed2000

Tailgut cyst in a neonate.

Tailgut cyst is a rare lesion of developmental origin located in the retrorectal space, which usually presents as a multilocular cystic mass. It is usually found in adults, and neonatal cases are extremely rare. The authors report a tailgut cyst in a neonate that was found by prenatal ultrasonogram, which was like a teratoma in gross appearance.

Cysts↗
PubMed2000

25,27-(6-Tosyl-3,9-dioxa-6-azaundecane-1,11-diyldioxy)-26,28-(3,6, 9-trioxaundecane-1,11-diyldioxy)calix[4]arene.

A new calix[4]-crowned azacrown ether, C(51)H(59)NO(11)S, consisting of four phenyl rings in a 1,3-alternate conformation was synthesized from the reaction of 25, 27-bis(5-chloro-3-oxapentyloxy)calix[4]crown-5 and p-toluenesulfonamide in the presence of Cs(2)CO(3). A crown-5 loop was attached on the two facing lower rims of the calix[4]arene and the N-tosyl azacrown group was attached on the other set of lower rims of the calix[4]arene backbone. This molecule seems to offer an inside cavity for the formation of a host-guest complex.

Journal Article↗
PubMed2000

Template nucleotide moieties required for de novo initiation of RNA synthesis by a recombinant viral RNA-dependent RNA polymerase.

The recombinant RNA-dependent RNA polymerase of the bovine viral diarrhea virus specifically requires a cytidylate at the 3' end for the de novo initiation of RNA synthesis (C. C. Kao, A. M. Del Vecchio, and W. Zhong, Virology 253:1-7, 1999). Using RNAs containing nucleotide analogs, we found that the N3 and C4-amino group at the initiation cytidine were required for RNA synthesis. However, the ribose C2'-hydroxyl of the initiating cytidylate can accept several modifications and retain the ability to direct synthesis. The only unacceptable modification is a protonated C2'-amino group. Quite strikingly, the recognition of the functional groups for the initiation cytidylate and other template nucleotides are different. For example, a C5-methyl group in cytidine can direct RNA synthesis at all template positions except at the initiation cytidylate and C2'-amino modifications are tolerated better after the +11 position. When a 4-thiouracil (4sU) base analog that allows only imperfect base pairing with the nascent RNA is placed at different positions in the template, the efficiency of synthesis is correlated with the calculated stability of the template-nascent RNA duplex adjacent to the position of the 4sU. These results define the requirements for the specific interactions required for the initiation of RNA synthesis and will be compared to the mechanisms of initiation by other RNA-dependent and DNA-dependent RNA polymerases.

Animals↗
PubMed2000

Biliary dilatation: differentiation of benign from malignant causes--value of adding conventional MR imaging to MR cholangiopancreatography.

PURPOSE: To determine the value of conventional T1 - and T2-weighted images and gadolinium-enhanced dynamic magnetic resonance (MR) images as a supplement to MR cholangiopancreatographic (MRCP) images in differentiation of benign from malignant causes of biliary dilatation. MATERIALS AND METHODS: MR studies in 62 patients with biliary dilatation with proved causes included conventional T1- and less heavily T2-weighted images, as well as gadolinium-enhanced dynamic images and heavily T2-weighted MRCP images. Two radiologists reviewed MRCP images alone, MRCP images with nonenhanced T1 - and T2-weighted MR images, and MRCP images with nonenhanced and gadolinium-enhanced dynamic images. RESULTS: For differentiation of benign from malignant causes of biliary dilatation, the area under the receiver operating characteristic curve (A(z)) was significantly (P < .05) larger for MRCP images interpreted with T1 - and T2-weighted images (0.9547 for reader 1, 0.8404 for reader 2) than for MRCP images alone (0.8144 for reader 1, 0.8122 for reader 2). The addition of gadolinium-enhanced dynamic MR images to MRCP images with nonenhanced T1- and T2-weighted images did not significantly increase accuracy (A(z) = 0.9554 for reader 1 and 0.8650 for reader 2), but the level of confidence was increased in 17%-24% of cases. CONCLUSION: Use of nonenhanced T1- and less heavily T2-weighted images with MRCP images significantly improved the diagnostic accuracy of MR examinations of pancreaticobiliary disease.

Adolescent↗
PubMed2000

Biliary atresia in neonates and infants: triangular area of high signal intensity in the porta hepatis at T2-weighted MR cholangiography with US and histopathologic correlation.

PURPOSE: To correlate a triangular area of high signal intensity in the porta hepatis on T2-weighted magnetic resonance (MR) cholangiograms of biliary atresia with ultrasonographic (US) and histopathologic findings in a portal mass observed during a Kasai procedure. MATERIALS AND METHODS: Twenty-one consecutive neonates and infants (age range, 13-88 days; mean age, 59 days) with cholestasis underwent US and single-shot MR cholangiography. In 12 patients with biliary atresia diagnosed at histopathologic examination, MR cholangiographic findings in the porta hepatis were correlated with US and histopathologic findings in the portal mass. RESULTS: At US, eight of the 12 patients had round, linear, or tubular hypoechoic portions within a triangular cord; MR cholangiography revealed a triangular area of high signal intensity confined to the porta hepatis. Histopathologic examination of the portal mass revealed a cystic or cleftlike lesion surrounded by loose myxoid mesenchyme and platelike fetal bile ducts. Neither the large cystic lesion without ductal epithelium nor the small cleftlike lesion with scanty epithelium demonstrated bile staining. Similar areas of high signal intensity were not seen on T2-weighted images in the remaining patients (four with biliary atresia and nine with neonatal hepatitis). CONCLUSION: In biliary atresia, T2-weighted single-shot MR cholangiography can show a triangular area of high signal intensity in the porta hepatis that may represent cystic dilatation of the fetal bile duct.

Bile↗