Biomedical subjects

J K Han

Publications and source records attributed to J K Han.

At least 91 records · Page 5Linked to original sources

PubMed1996

Hepatic tumors: predisposing factors for complications of transcatheter oily chemoembolization.

PURPOSE: To elucidate major complications and their predisposing factors in transcatheter oily chemoembolization (TOCE) for hepatic tumors. MATERIALS AND METHODS: In a retrospective study of 351 patients (aged 26-82 years) with hepatic tumors, TOCE was performed 942 times with an emulsion of iodized oil (3-40 mL) and doxorubicin hydrochloride (20-60 mg). In 126 patients, TOCE was followed by absorbable gelatin sponge embolization. RESULTS: Complications were severe postembolization syndrome (n = 53); hepatic insufficiency (n = 20), infarction (n = 1), or abscess (n = 1); intrahepatic biloma formation (n = 3); tumor rupture (n = 3); septicemia (n = 9); coagulopathy (n = 1); gastrointestinal bleeding (n = 10); gallbladder (n = 5) or splenic infarction (n = 4); pulmonary oil embolism (n = 6); and spinal cord injury (n = 1). Important predisposing factors were major portal vein obstruction, compromised hepatic functional reserve, biliary obstruction, previous biliary surgery, excessive amount (> 20 mL) of iodized oil, hepatic arterial occlusion after repeated TOCE, and nonselective embolization. CONCLUSION: Most patients with major complications after TOCE had preexisting risk factors.

Adult↗

PubMed1996

Power versus conventional color Doppler sonography: comparison in the depiction of vasculature in liver tumors.

PURPOSE: To compare power and conventional color Doppler sonography in the depiction of the intratumoral vasculature of hemangiomas, hepatocellular carcinomas (HCCs), and metastases of the liver. MATERIALS AND METHODS: Thirty-two patients with liver tumors (12 hemangiomas, 11 HCCs, and nine metastases) were prospectively evaluated with power and conventional color Doppler sonography by using a 2-4-MHz convex probe with 2-MHz Doppler frequency. Power Doppler sonography was performed with a 75%-88% gain. Conventional color Doppler sonography was performed with a 55%-75% gain and a pulse repetition frequency of 700 Hz. Power Doppler signals and color Doppler signals interrogated in one plane were analyzed by two radiologists, who subjectively rated power Doppler sonography as superior, equal, or inferior to color Doppler sonography. RESULTS: Overall, power Doppler sonography was superior to color Doppler sonography in 18 patients and equal in 14 (P < .01). In hemangiomas, power Doppler sonography was superior to color Doppler sonography in 10 patients and equal in two (P < .01). In HCCs, power Doppler sonography was superior to color Doppler sonography in four patients and equal in seven (P > .05). In metastases, power Doppler sonography was superior to color Doppler sonography in four patients and equal in five (P < .05). CONCLUSION: Power Doppler sonography is more sensitive than color Doppler sonography in the depiction of the vasculature of liver tumors, particularly in hemangiomas.

Adult↗

PubMed1996

Hemodynamic characteristics of extracellular UTP in the perfused rat liver.

Uridine 5'-triphosphate (UTP) is stored in the granules of cells such as platelets and is released into the extracellular space upon cell stimulation. Extracellular UTP is known to influence many biological processes. We investigated the hemodynamic effects of UTP on the perfused rat liver and characterized its receptors. Liver perfusions were performed in a recirculation system under constant pressure (28 cmH2O). The perfusion flow and oxygen consumption rate were measured at 30 second intervals. UTP decreased the perfusion flow and the oxygen consumption rate, dose-dependently. UTP-induced changes were transient and disappeared in about 10 minutes. Suramin (P2-purinergic antagonist, 100 uM) and indomethacin (cyclooxygenase inhibitor, 20 uM) blocked UTP-induced hemodynamic changes significantly. The effects of UTP were also inhibited when Kupffer cells were damaged with treatment of gadolinium chloride (10 mg/kg iv). L-NAME (1 mM), a potent inhibitor of nitric oxide synthase, markedly enhanced and prolonged the contractile response of UTP in the hepatic vessel. These results suggest that UTP acts mainly on suramin-sensitive UTP receptors on the Kupffer cell through prostanoid synthesis. The nitric oxide systems in the endothelium seem to counteract the vasoconstrictile action of UTP in the hepatic circulation.

Animals↗

PubMed1995

Reducing PIP2 hydrolysis, Ins(1,4,5)P3 receptor availability, or calcium gradients inhibits progesterone-stimulated Xenopus oocyte maturation.

In this report, we investigated the possibility that a product of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), and its downstream effector, Ca2+, is involved in oocyte maturation. Microinjection of monoclonal antibody specifically directed to PIP2 into oocytes prior to progesterone addition inhibited meiotic maturation. In addition, preventing or suppressing the progesterone-induced increase in [Ca2+]i and maintaining cytosolic free Ca2+ of oocyte at 0.1 or 0.3 microM by Br2-BAPTA buffered Ca2+ solutions, completely blocked maturation. However, raising cytosolic Ca2+ concentration of oocyte to 1.0 or 3.0 microM, the inhibitory Br2-BAPTA effects on oocyte maturation was greatly diminished. Finally, microinjection of heparin, a potent antagonist of Ins(1,4,5)P3 receptor, inhibited progesterone-induced oocyte maturation in a manner that is linearly proportional to its cytoplasmic concentration. These results strongly support the hypothesis that PIP2 turnover as well as Ins(1,4,5)P3-induced Ca2+ release play crucial roles in regulating normal meiotic cell division in Xenopus oocyte.

Animals↗

PubMed1995

Characterization of focal hepatic tumors. Value of two-phase scanning with spiral computed tomography.

BACKGROUND: Spiral computed tomography (CT) allows imaging of the liver during the peak contrast material levels due to the capability of fast data acquisition. The objective of this study was to evaluate the usefulness of two-phase spiral CT in the differential diagnosis of focal hepatic tumors. METHODS: One hundred two patients who had hepatic tumors (211 nodules; 149 hepatocellular carcinomas [HCCs], 36 metastases, and 26 hemangiomas) underwent two-phase spiral CT with 10-mm collimation at 10 mm/second table speed and 120 mL of contrast material injected at the rate of 3 mL/second. Computed tomography images of the hepatic arterial phase and late (equilibrium) phase were obtained at 35-second and 180-second delays, respectively. The enhancement patterns of tumors were divided into six types and were compared with the attenuation of surrounding liver parenchyma: totally high, peripherally high, centrally high, mixed, iso, and low. RESULTS: The common enhancement patterns of HCC in two-phase spiral CT were totally high in the arterial phase and low (n = 63, 42%) or iso (n = 28, 19%) in the late phase. Metastasis showed peripherally nonnodular high attenuation (n = 9, 25%) or low attenuation (n = 9, 25%) in the arterial phase and low attenuation in the late phase, followed by totally high attenuation in the arterial phase and iso in the late phase (n = 6, 17%). Hemangiomas showed totally or peripherally nodular enhancement in the arterial and late phases (n = 23, 89%). In distinguishing hemangiomas from malignant tumors, totally high or peripherally nodular high attenuation in the late phase was the most useful contrast enhancement pattern (96% of hemangioma vs. 0% of malignant tumors). In distinguishing HCCs from metastases, a combination of contrast enhancement pattern of totally high attenuation in the arterial phase and low in the late phase was the most useful contrast enhancement pattern (42% of HCCs vs. 0% of metastases). The predictability of differentiation between hemangiomas and malignant tumors and between HCCs and metastases was 99% and 90% with spiral CT, respectively. CONCLUSIONS: Two-phase spiral CT is useful in the differential diagnosis of focal hepatic tumors with evaluation of contrast enhancement patterns.

Adult↗

PubMed1995

Oscillation of inositol polyphosphates in the embryonic cleavage cycle of the Xenopus laevis.

Evidence suggests that a transient increase in intracellular calcium ([Ca2+]i) is an important modulator during the cell division cycle in early embryos. We have recently shown that inhibition of Ins(1,4,5)P3-induced Ca2+ release in the cleaving Xenopus embryos greatly lengthens the cell cycle duration. In this report, we have directly measured the changes of Ins(1,4,5)P3 content during the first two cleavage cycles in the Xenopus embryos. HPLC profiles of cell extracts from dividing embryos show oscillations of inositol polyphosphates throughout the cleavage cycle with a transient production of Ins(1,4,5)P3 by the time of cleavage furrow completion. In addition, cyclic changes in inositol phospholipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 4-phosphate (PIP) were detected during the cleavage cycle. These data strongly suggest the involvement of PIP2 turnover and periodic increase in Ins(1,4,5)P3 triggers [Ca2+]i transients during the early embryonic cell cycle in the Xenopus.

Animals↗

PubMed1995

Hepatocellular carcinoma and portal vein invasion: results of treatment with transcatheter oily chemoembolization.

OBJECTIVE: Our objective was to evaluate the efficacy and safety of transcatheter oily chemoembolization therapy in a series of patients with hepatocellular carcinoma and portal vein invasion. MATERIALS AND METHODS: We retrospectively analyzed the results of transcatheter oily chemoembolization for 110 patients with hepatocellular carcinoma invading major portal branches. The Child's classes were A for 94 patients and B for 16. The main portal vein was partially (n = 33) or completely (n = 15) invaded in 48 patients, the right portal vein was invaded in 36, and the left portal vein was invaded in 26. Oily chemoembolization was performed with an emulsion of iodized oil and doxorubicin hydrochloride. Gelatin sponge particle embolization was added for 78 patients. Seventy-one patients underwent multiple treatment sessions. RESULTS: Our initial findings showed that 31 patients had complete or partial remission, with an overall median survival time of 6 months. The cumulative survival rates were 48% (6 months), 30% (1 year), 18% (2 years), and 9% (3 years). The parenchymal tumor extent was the most significant predicting factor for complications and efficacy of therapy. Of 33 patients with a parenchymal tumor limited to one or two segments of a hepatic lobe, 22 had complete or partial remission, with a median survival time of 22 months; this survival time was significantly longer than that (5 months) for 77 patients with a more extensive tumor (p < .0001). Hepatic insufficiency developed in 10 patients, and three of them died within 1 month after chemoembolization. All 10 patients had an extensive parenchymal tumor involving more than two hepatic segments, and four had impaired hepatic functional reserve of Child's class B. CONCLUSION: When a tumor is limited in extent and hepatic function is preserved, transcatheter oily chemoembolization is effective and safe for the palliation of hepatocellular carcinoma and major portal vein invasion. However, when a parenchymal tumor is extensive, chemoembolization is associated with a poor response and a risk of hepatic failure.

Adolescent↗

PubMed1994

Renal parenchymal abnormalities associated with renal vein thrombosis: correlation between MR imaging and pathologic findings in rabbits.

OBJECTIVE: The purpose of this study was to correlate abnormalities of the renal parenchyma seen on MR images with pathologic findings in rabbits with acute thrombosis of the renal vein. MATERIALS AND METHODS: MR images were obtained in 21 rabbits before and 1 hr to 2 weeks after ligation of the renal vein. MR findings were correlated with pathologic findings. RESULTS: The cross-sectional area of the kidney was 1.7, 1.8, 1.9, 2.2, 1.3, and 1.0 times of its initial size at 1 hr, 3 hr, 1 day, 3 days, 1 week, and 2 weeks, respectively, after ligation of the renal vein. Corticomedullary contrast on T1-weighted images decreased persistently from 1 hr to 2 weeks after ligation. Between 1 hr and 1 week after ligation, T2-weighted images showed a layer with low signal intensity that was correlated with medullary congestion and hemorrhage on pathologic specimens. CONCLUSION: MR images show a layer with low signal intensity in the renal medulla that probably represents medullary congestion and hemorrhage of the kidney in rabbits with acute thrombosis of the renal vein.

Adult↗

PubMed1994

Primary angiosarcoma of the spleen. CT and MR imaging.

The CT and MR findings in 2 patients with surgically proven splenic angiosarcoma are presented. Two distinctive radiologic and pathologic patterns were observed: total tumor replacement of the spleen with preservation of normal contour or multiple nodular masses in the spleen. The various findings on CT and MR imaging reflected the hemorrhagic nature of the lesions with increased iron content. MR imaging appeared to be superior to CT in demonstrating these features. In the case of focal lesions, radiologic differentiation from lymphoma or metastasis was impossible.

Adult↗

PubMed1993

Embryonic expression of Fgf-6 is restricted to the skeletal muscle lineage.

As part of an ongoing examination of the functions of the fibroblast growth factor (FGF) gene family in mammalian development, we have carried out an RNA in situ hybridization analysis of the Fgf-6 gene in the mouse embryo. In contrast to what has been found for three other members of the FGF gene family, no Fgf-6 RNA was detected in mouse embryos at E6.5 through E8.5. Fgf-6 RNA was first detected in embryos at E9.5 and was localized exclusively in the myotomal compartment of the somite. Similar results were obtained with embryos at E10.5 and E11.5. At E12.5, expression was still detected in the myotome, and also in the region containing the developing muscles of the body wall. By E14.5, Fgf-6 RNA was found in the majority of skeletal muscles in the fetus. These results are discussed in comparison with what is known about the expression patterns of the genes encoding other FGF family members, as well as their high-affinity receptors.

Animals↗

PubMed1993

Tuberculous stricture of the urinary tract: antegrade balloon dilation and ureteral stenting.

In eight patients with tuberculous strictures of the urinary tract, antegrade balloon dilation and ureteral stenting was attempted. In six patients, antegrade balloon dilation was successfully performed; however, the procedure was aborted in the remaining two patients due to the failure in passing a guidewire through the stenotic lesions. In six patients in whom balloon dilation and ureteral stenting were performed, a total of nine stenotic lesions were dilated. Those were four ureteric lesions, two lesions of ureteropelvic junctions, two lesions of ureterovesical junctions, and a lesion of calyceal infundibulum. In all six patients in whom balloon dilation and ureteral stenting was successfully accomplished, intravenous urograms obtained 9-31 months after the procedure showed improvements both in contrast media excretion and in prestenotic dilatation. Antegrade balloon dilation of the urinary tract combined with ureteral stenting was an effective technique for the management of stenoses secondary to tuberculosis of the urinary tract.

Adult↗

PubMed1993

Radiological findings of human fascioliasis.

Fasciola hepatica is a trematode of herbivorous mammals. Humans are accidentally infected by the ingestion of water or raw aquatic vegetables contaminated with the metacercaria. Radiological findings of six patients with fascioliasis (five hepatic fascioliasis, one biliary fascioliasis) were analyzed. The diagnosis was based on serological testing and/or histopathologic findings of eosinophilic abscess in five patients and identification of the adult worm in one patient. The characteristic radiological features of hepatic fascioliasis were (1) cluster of microabscesses arranged in tract-like fashion (burrow tract), (2) subcapsular location of the hepatic lesions, and (3) very slow evolution of the lesion on follow-up examinations. In biliary fascioliasis, there were multiple conglomerated filling defects in the common bile duct. The authors believe that the demonstration of these features, together with peripheral eosinophilia or eosinophilic aspirate from the hepatic lesion, is very helpful in making the correct diagnosis.

Adolescent↗

PubMed1993

Pulmonary oil embolism after transcatheter oily chemoembolization of hepatocellular carcinoma.

The medical records of 336 patients with hepatocellular carcinoma who underwent transcatheter oily chemoembolization (TOCE) performed via the hepatic artery were retrospectively reviewed to ascertain the occurrence of symptomatic pulmonary oil embolism. In 14 patients, more than 20 mL of iodized oil was administered. In six of these 14 patients, respiratory symptoms of cough, hemoptysis, and dyspnea developed 2-5 days after TOCE, and their chest radiographs showed diffuse bilateral pulmonary parenchymal infiltrate. Their arterial partial pressure of oxygen while they breathed room air ranged from 39 to 60 mm Hg during maximum hypoxemia. The symptoms, arterial hypoxemia, and chest radiographic abnormalities completely cleared 10-28 days after TOCE in the five patients who survived. One patient died 10 days after TOCE because of respiratory arrest with a progression of pulmonary infiltrate. Although histopathologic proof is lacking, it is concluded that massive pulmonary embolization of iodized oil was the primary cause of the clinical and radiographic manifestations in these six patients.

Adult↗

PubMed1993

Left paracardiac mass caused by dilated pericardiacophrenic vein: report of four cases.

OBJECTIVE: The pericardiacophrenic vein is a possible route of collateral circulation when either the superior or the inferior vena cava is obstructed. When the vein is dilated, it can cause an abnormal appearance on chest radiographs. We describe four such patients. MATERIALS AND METHODS: We studied four patients who had abnormalities on conventional chest radiographs due to a grossly dilated pericardiacophrenic vein, confirmed by means of venacavography, CT, or MR imaging. We analyzed the cause of the dilatation and the radiologic findings associated with the dilated pericardiacophrenic vein. RESULTS: The cause of the dilated pericardiacophrenic vein was the membranous obstruction of the inferior vena cava in all four patients. Chest radiographs revealed an undulating vascular shadow (in two cases) or a shadow of several masses (in one case) along the left border of the heart or a poorly defined haziness mimicking a pulmonary parenchymal infiltrate (in one case). A direct communication between the left hepatic vein and the left inferior phrenic vein was seen near their insertion into the inferior vena cava in three cases. Hepatic venous outflow and some of the systemic venous return were directed to this left inferior phrenic-pericardiacophrenic route. CONCLUSION: When obstruction of the inferior vena cava is clinically suspected and the chest radiograph shows abnormalities at the left paracardiac area, a dilated pericardiacophrenic vein due to obstruction in the suprahepatic portion of the inferior vena cava, most likely a membrane, should be considered in the differential diagnosis.

Adult↗

PubMed1993

Piezoelectric lithotripsy of radiopaque gallstones: results and six-month follow-up.

Sixty-eight patients with radiopaque gallbladder stones (38 with a single stone, 30 with multiple stones) were treated with piezoelectric extracorporeal shock wave lithotripsy (ESWL) and results were compared with those of 69 patients with radiolucent stones (28 with a single stone, 41 with multiple stones). Stones were fragmented to 4 mm or less in 76.8% after 41,466 +/- 36,504 shock waves in the radiolucent stone group and 77.9% after 54,686 +/- 51,024 shock waves in the radiopaque stone group (p = 0.876 and 0.130, respectively). In 137 patients, ten patients were lost to follow-up. Average period of follow-up was 220 +/- 198 days. Six-month clearance rate of the radiolucent stone group was 43.5% and that of the radiopaque stone group was 16.4% (p less than 0.05) Figure 1. Six-month clearance rate of patients with single stones smaller than 2 cm was also significantly higher in the radiolucent stone group than in the radiopaque stone group (69.5% vs 18.6%; p less than 0.01). However, in patients with multiple stones, the presence of calcification did not affect rates of successful fragmentation or 6-month clearance. There was no statistically significant difference in incidence of complications between the radiolucent and radiopaque stone groups. Although the number of cases are small and the follow-up period is short, our results of ESWL on radiopaque gallstones are so far not satisfactory in terms of stone clearance. Strict patient selection is needed unless there is an improvement in the lithotripsy procedure or post-lithotripsy management.

Adult↗

PubMed1993

Hematogeneous pulmonary metastasis. An experimental study using VX-2 carcinoma in rabbits.

The purpose of this study was to develop an experimental model of pulmonary metastases using VX-2 tumor, and to describe sequential radiologic and pathologic findings with special attention to the interstitial changes around the metastatic nodules. Through ear veins of 25 rabbits, VX-2 tumor cell suspension was injected with 0.8-mm scalp needles. Chest radiographs were taken every other day after tumor injection. The rabbits were sacrificed at scheduled times from 3 to 30 days after tumor injection. The inflated and fixed lungs were examined with visual inspection, low-kV radiography, high resolution CT (HRCT), microradiography of the sliced lung and with histopathologic studies. Hematogeneous pulmonary metastases occurred in 24 of 25 rabbits. In addition to the metastatic nodules, perinodular and peribronchovascular infiltrations were seen on low-kV radiography, HRCT, microradiography and histologic studies.

Animals↗

PubMed1992

Calcified gastric carcinoma: CT findings.

The computed tomographic (CT) findings of 13 cases of calcified gastric carcinoma were analyzed retrospectively. Eleven cases were confirmed as a mucinous adenocarcinoma by surgery (three cases), or endoscopic biopsy (eight cases). Two cases were diagnosed as adenocarcinoma by endoscopic biopsy. In all cases the calcifications were of the punctate or miliary shape and the size varied from 1-3 mm in diameter. The calcifications were located in the thickened gastric wall in all cases, and were seen in metastatic lesions such as lymph nodes and the liver in two cases. In 10 cases, some tumor portions showed lower attenuation number than that of the muscle on CT scans, and corresponded to mucin pool in tumor portions histologically. Twelve cases were in inoperable advanced stage.

Adenocarcinoma, Mucinous↗

PubMed1992

Retrieval of intravascular foreign bodies with the snare and catheter capture technique.

The authors report two cases of retrieval of iatrogenically placed intravascular metallic foreign bodies: a guide wire in the abdominal aorta and a guide-wire fragment in the inferior vena cava. The foreign bodies were retrieved with use of a new approach described as the "snare and catheter capture technique." This technique is useful with guide wires that are too stiff to safely remove doubled over.

Aorta, Abdominal↗