PubMed Health⌕ Search

Biomedical subjects

A H Kwon

Publications and source records attributed to A H Kwon.

At least 19 recordsLinked to original sources
PubMed2002

Preoperative laparoscopic examination using surgical manipulation and ultrasonography for pancreatic lesions.

BACKGROUND AND STUDY AIMS: Unnecessary laparotomies in patients with advanced pancreatic disease are unlikely to provide any benefits and may compromise both the quality and duration of survival. The purpose of this study was to determine the contribution of laparoscopy and laparoscopic ultrasound to the diagnosis or staging, or both, of pancreatic lesions. PATIENTS AND METHODS: Fifty-two patients were diagnosed preoperatively with pancreatic cancer. The diagnoses made by laparoscopic ultrasonography (LUS) were compared with those made prior to the operation. Laparoscopic visualization of the body of the pancreas was obtained via an infragastric approach. For the laparoscopic examination of the head of the pancreas, a retroduodenal approach was used. RESULTS: In 52 patients with cancer of the pancreatic head and body, unresectable findings were observed in 13 patients. Portal vein displacement without other unresectable findings was evident in six patients using LUS, and was confirmed at exploratory laparotomy in five patients. The surgical approaches were changed, with seven patients undergoing an open exploration for biliary drainage and the other six patients receiving endoscopic endoprostheses. In six of the 52 patients, LUS-guided needle biopsies and frozen-section examinations detected chronic pancreatitis (n = 4), a malignant lymphoma (n = 1), and an abdominal tuberculosis (n = 1), which were diagnosed preoperatively as pancreatic cancers and cysts. Only one patient undergoing the laparoscopic procedure had acute pancreatitis; this patient was treated conservatively. CONCLUSIONS: LUS, when combined with laparoscopic manipulations, may overcome many of the limitations of laparoscopy alone in the investigation of pancreatic lesions by providing an accurate diagnosis and assessment of the size and extent of the local dissemination.

Adult↗
PubMed2001

FK506, but not cyclosporin A, prevents mitochondrial dysfunction during hypoxia in rat hepatocytes.

Hepatic ischemia/reperfusion injury occurs in the clinical situations including liver transplantation. FK506 and cyclosporin A (CsA) are reported to be hepatotrophic agents in addition to being a powerful immunosuppressive agent. Studies were performed to determine whether the drugs influence a mitochondrial dysfunction under the hypoxic conditions in primary culture model of rat hepatocytes. The Anaeropack system was used for cell culture to create a hypoxia. Cells were treated with FK506 or CsA under the normoxic and hypoxic conditions. Hypoxia markedly decreased intracellular adenosine 5'-triphosphate (ATP) contents and the ketone body ratio (KBR, acetoacetate/beta-hydroxybutyrate) in culture medium as compared with normoxia. FK506 prevented the decreases of ATP contents and the KBR. In contrast, CsA had no effect on either ATP contents or the KBR. FK506, but not CsA, increased the KBR under the normoxic conditions. Under the hypoxic conditions, heat shock protein 70 (Hsp70) was detected after reoxygenation. FK506 enhanced the induction of Hsp70, but CsA again had no effect on Hsp70 induction. These results indicate that FK506 protects the hypoxia injury in part by preventing the mitochondrial dysfunction in concert with the enhancement of heat shock response in hepatocytes.

Adenine Nucleotides↗
PubMed2001

Perioperative blood transfusion in hepatocellular carcinomas: influence of immunologic profile and recurrence free survival.

BACKGROUND: The postoperative recurrence of hepatocellular carcinomas (HCC) associated with perioperative blood transfusion has been the subject of controversy. The authors prospectively investigated the relation between perioperative allogeneic blood transfusions, the recurrence free survival, and the immunologic profiles of patients with HCC who had undergone curative hepatic resections. METHODS: One hundred eight patients were divided into two groups: a transfused group (n = 53) and a nontransfused group (n = 55), according to their perioperative transfusion history. The subsets of lymphoid cells, natural killer cell activity and the phytohemagglutinin (PHA) response were all measured preoperatively, and at 1, 2, and 4 weeks and at 3 and 6 months after the hepatectomy. The recurrence free survival rate then was compared between these two groups. RESULTS: There were no significant differences between these two groups with respect to histologic findings, clinical stage, type of resection, pathologic data, and the recurrence free survival rate. Postoperative levels of the CD8 in the transfused group were elevated as compared with the nontransfused group, and the PHA response of the transfused patients was significantly increased at 7 postoperative days. Natural killer cell activity of the transfused patients was decreased at 7 postoperative days, as compared with the nontransfused patients, but there was no significant difference. CONCLUSIONS: Although allogeneic blood transfusion may have immunosuppressive effects, perioperative blood transfusions did not influence the cancer free survival rate in patients with hepatocellular carcinoma.

Adult↗
PubMed2001

Laparoscopic management of bile duct and bowel injury during laparoscopic cholecystectomy.

Accidental injuries to the bile duct and bowel are significant risks of laparoscopic surgery and sometimes require conversion to open surgery. Although some of the injuries related to laparoscopic cholecystectomy can be managed by endoscopic techniques, laparoscopic surgery is not yet sufficiently perfected. We investigated the efficacy of laparoscopic management combined with endoscopic tube or stent insertion in cases of bile duct and bowel injuries during laparoscopic cholecystectomy. Laparoscopic cholecystectomy was attempted on 1,190 consecutive patients between April 1992 and June 1999. The first 70 patients underwent only preoperative intravenous infusion cholangiography (IVC), and the remaining 1,120 patients were subjected to both preoperative IVC and intraoperative cholangiography. We experienced 16 cases of bile duct injury (1.4%). Five patients with circumferential injuries of the bile duct were converted to open surgery for biliary reconstruction. The other 11 patients with partial laceration injuries of the bile duct and biliary leakage from the cystic duct underwent a laparoscopic simple closure technique. In 10 of these patients, an endoscopic tube or stent was inserted on the day after surgery to facilitate biliary decompression and drainage. Bowel injuries occurred in seven patients (0.6%). Three intestinal injuries were due to careless technique, and two duodenal injuries and two intestinal injuries were related to dense adhesions. All of these injuries were successfully repaired using laparoscopic techniques, autosuturing devices, or extracorporeal suturing via the umbilical incision. No postoperative complications were identified. We concluded that the biliary injury site could be closed with a laparoscopic technique so long as the biliary injury was not circumferential. Bowel injuries also could be repaired laparoscopically.

Adolescent↗
PubMed2001

Laparoscopic splenectomy for a lymphangioma of the spleen: report of a case.

We present the first case report of a successful laparoscopic complete excision of a splenic lymphangioma. The splenic tumor was preoperatively diagnosed to be a lymphangioma by the combined modalities of ultrasonography, computed tomography, magnetic resonance imaging, and angiography. A laparoscopic splenectomy was subsequently performed and the pathological examination of the mass confirmed the diagnosis of a lymphangioma. Based on the above findings, a laparoscopic splenectomy is recommended when a splenic tumor is suspected to be either benign or borderline.

Aged↗
PubMed2001

Ruptured dissecting aneurysm in bilateral iliac arteries caused by Ehlers-Danlos syndrome type IV: report of a case.

Ehlers-Danlos syndrome (EDS) is an inherited disorder of connective tissue characterized by hyperextensible skin, hypermobile joints, and abnormalities of the cardiovascular system. Ten types and several subtypes of EDS have so far been recognized based on genetic, clinical, and biochemical characteristics. The spectrum of the disorder varies from mild to life-threatening vascular complications. EDS type IV is a particularly dangerous form with a lethal spontaneous rupture of the major arteries and aneurysmal formation. We present herein a case of a ruptured dissecting aneurysm in the bilateral iliac arteries caused by EDS type IV. A previously healthy 33-year-old man without any physical features of this connective tissue disorder experienced a metachronous vascular rupture two times. Successful synthetic bypass grafting was performed with great difficulty. The diagnosis of EDS type IV was made afterwards based on an electrophoresis analysis of a skin biopsy specimen which revealed a lack of type III collagen. Surgical intervention in cases of arterial complications in EDS type IV patients have been reported to be both difficult and frequently unsuccessful. The early clinical recognition of this syndrome is therefore of great importance due to the hazards of such surgical therapies.

Adult↗
PubMed2001

Laparoscopic cholecystectomy and choledocholithotomy in patients with a previous gastrectomy.

BACKGROUND: An increased incidence of cholelithiasis has been widely reported after truncal vagotomy and after gastric resection. In the early phase of patient selection, previous gastrectomy has been considered a relative contraindication to laparoscopic cholecystectomy (LC). In this study, we examined the management of LC in patients with previous gastrectomy. STUDY DESIGN: LC was attempted on 1,260 consecutive patients. Of these patients, 29 had a previous gastrectomy. Surgical procedures that had been performed included Billroth I gastrectomies (15), Billroth II gastrectomies (10), and total gastrectomies (4). There were 23 cases of cholelithiasis, 4 chronic cholecystitis, 2 gallbladder polyps, I porcelain gallbladder, and I gallbladder cancer. Nine patients were diagnosed with stones in their common bile duct or common hepatic duct. RESULTS: Preoperatively, seven of nine patients with common bile duct stones were subjected to endoscopic sphincterotomy, and the stones were removed successfully from five of these patients. In the remaining two patients, common bile duct stones were removed by laparoscopic choledocholithotomy by choledochotomy. The LC was completed in 26 patients (90%) who had undergone previous gastrectomy. In 449 patients who had previous abdominal surgery without a gastrectomy, only 4 patients (0.9%) required open surgery. In contrast, three patients (10%) with previous gastrectomy required open surgery. No major complications were recorded in this study series, and no residual or retained stones were seen during a followup period of 3 months. CONCLUSIONS: Clear visualization of anatomic structures and landmarks, and scrupulous hemostasis are needed to perform a safe LC in these patients. We conclude that in our study patients, a previous gastrectomy is considered an indication for LC and laparoscopic choledochotomy.

Adult↗
PubMed2001

Cold preservation of rat pancreatic islets just above the freezing point using University of Wisconsin solution.

AIMS: To confirm whether rat islets stored at a temperature just above the freezing point using University of Wisconsin (UW) solution would remain viable for the short term. METHODOLOGY: Rat islets were stored for 24 hours in UW solution, either at 4 degrees C or at -0.6 degrees C (just above the specific freezing point of the UW solution). After cold storage, the islets were assessed for in vitro viability by static incubation and for in vivo viability by a transplantation study. One thousand islets preserved under different conditions were injected intraportally into a streptozotocin-induced diabetic rat as an isograft. Four weeks after the transplantation, an intravenous glucose tolerance test was performed. RESULTS: Islets stored at -0.6 degrees C showed higher insulin secretion rates than those stored at 4 degrees C on a static challenge. The interval from transplantation to the achievement of normoglycemia was also shorter in the -0.6 degrees C group than in the 4 degrees C group. After islet transplantation, the daily nonfasting plasma glucose concentration was higher in the 4 degrees C group than in the -0.6 degrees C group. When compared with the 4 degrees C group, the -0.6 degrees C group showed lower blood glucose values during all investigational periods on an intravenous glucose tolerance test. CONCLUSION: Islet preservation at -0.6 degrees C using UW solution is more advantageous for short term.

Animals↗
PubMed2001

Functional hepatic volume measured by technetium-99m-galactosyl-human serum albumin liver scintigraphy: comparison between hepatocyte volume and liver volume by computed tomography.

OBJECTIVES: We investigated the usefulness of measuring the functional hepatic volume by single-photon emission CT with 99m-technetium galactosyl-human serum albumin scintigraphy (GSA-LV). We then compared this value to the total hepatocyte volume and the hepatic volume determined from CT (CT-LV) in the patients with hepatobiliary tumors. METHODS: Forty-seven patients were divided into two groups, the SM group (subsegmentectomy and monosegmentectomy) and the DT group (disegmentectomy and trisegmentectomy). These groups were further divided into subgroups with or without chronic hepatitis or cirrhosis. The GSA-LV, CT-LV, and the total hepatocyte volume were then calculated. The GSA-LV and CT-LV measurements were performed preoperatively, at 2 and 4 wk, and at 3 and 6 months after surgery. RESULTS: The preoperative GSA-LV values were significantly correlated with the hepatocyte volume and the 15-min retention rate of indocyanine green (ICGR15). Similarly, the hepatocyte volume correlated well with the CT-LV and ICGR15. However, the CT-LV was correlated only with the ICGR15. Recovery of the GSA-LV in the DT group was delayed, and about 90% of the volumetric and functional regeneration was observed within 6 months after the hepatectomy. In contrast, the CT-LV of DT group patients with normal liver remnants returned to approximately 90% of their initial volume within 1 month after the hepatectomy, whereas patients with injured livers regenerated gradually and regained approximately 80% of their preoperative value by 6 months after the hepatectomy. CONCLUSIONS: We conclude that the measurement of functional hepatic volume using the GSA-LV is useful in fully evaluating hepatic function based on hepatocyte volume.

Bile Duct Neoplasms↗
PubMed2001

A new method for tolerance induction: busulfan administration followed by intravenous injection of neuraminidase-treated donor bone marrow.

The portal venous (p.v.) administration of foreign cells induces donor-specific tolerance. Recently, we have demonstrated that the p.v. administration of donor cells elicits donor-specific tolerance across major histocompatibility complex barriers. In the present study, utilizing the intrahepatic tolerance-inducing system, we have established a new method for organ transplantation using both busulfan ([Bu] to provide a sufficient "space" for the donor hematopoietic cells to expand in the recipient) and neuraminidase ([Neu] to enhance the trapping of i.v.-injected cells in the liver). Radiolabeled bone marrow cells (BMCs) were found to exclusively accumulate in the livers of the recipients as a result of the Neu treatment. Furthermore, hematopoietic progenitors (forming hematopoietic foci) in the accumulated BMCs were retained in the recipient livers for at least 18 days. C57BL/6 (B6) mice that had been transplanted with skins of BALB/c mice immediately after the injection of BALB/c BMCs showed a 90% skin graft survival rate over 400 days as a result of using the combination of injecting 50 mg/kg Bu into the B6 mice and treatment of the BALB/c BMCs with 0.25 U/ml Neu (50 Bu + 0.25 Neu). However, the survival rate significantly decreased when either the Bu or Neu treatment was omitted. In tolerant recipients, microchimerism was observed in the various hematolymphoid organs. T cells collected from the tolerant recipients suppressed proliferative responses to the donor-alloantigens but enhanced the production of Th2 and Th3 cytokines. These findings suggest that the enhanced retention of donor BMCs in the recipient livers as a result of the Bu and Neu treatments efficiently induces tolerance induction. Therefore, this "single-day protocol" would be of great advantage for human organ transplantation.

Animals↗
PubMed2000

In vitro selection and characterization of a highly efficient Zn(II)-dependent RNA-cleaving deoxyribozyme.

A group of highly efficient Zn(II)-dependent RNA-cleaving deoxyribozymes has been obtained through in vitro selection. They share a common motif with the '8-17' deoxyribozyme isolated under different conditions, including different design of the random pool and metal ion cofactor. We found that this commonly selected motif can efficiently cleave both RNA and DNA/RNA chimeric substrates. It can cleave any substrate containing rNG (where rN is any ribo-nucleotide base and G can be either ribo- or deoxy-ribo-G). The pH profile and reaction products of this deoxyribozyme are similar to those reported for hammerhead ribozyme. This deoxyribozyme has higher activity in the presence of transition metal ions compared to alkaline earth metal ions. At saturating concentrations of Zn(2+), the cleavage rate is 1.35 min(-1)at pH 6.0; based on pH profile this rate is estimated to be at least approximately 30 times faster at pH 7.5, where most assays of Mg(2+)-dependent DNA and RNA enzymes are carried out. This work represents a comprehensive characterization of a nucleic acid-based endonuclease that prefers transition metal ions to alkaline earth metal ions. The results demonstrate that nucleic acid enzymes are capable of binding transition metal ions such as Zn(2+)with high affinity, and the resulting enzymes are more efficient at RNA cleavage than most Mg(2+)-dependent nucleic acid enzymes under similar conditions.

Base Sequence↗
PubMed2000

Recombinant human hepatocyte growth factor protects the liver against hepatic ischemia and reperfusion injury in rats.

BACKGROUND: Recent evidence indicates that hepatocyte growth factor (HGF) has a cytoprotective effect against hepatic injury caused by hepatotoxins and inflammatory cytokines. Studies were performed to determine whether HGF influences the survival rate of rats subjected to hepatic warm ischemia/reperfusion (WI/Rp) injury. METHODS: Male Sprague-Dawley rats were subjected to total or segmental hepatic ischemia by occluding the hepatic artery, portal vein, and bile duct with a microvascular clip. Rats were treated with four intravenous injections of recombinant human HGF (rhHGF 1 mg/kg) or the vehicle 72, 48, 24, and 12 h before surgery. RESULTS: None of the eight animals in the control group were alive 12 h after total hepatic WI/Rp. Seven of eight animals in the rhHGF-treated group were alive more than 2 days after the reperfusion. In the model of segmental hepatic ischemia, rhHGF inhibited the increase in cytokine-induced neutrophil chemoattractant in serum. The number of neutrophils infiltrating the liver was significantly lower in the rhHGF-treated group than in the control group. rhHGF prevented increases in the activity of serum alanine transaminase and in hepatic necrosis. Experiments with proliferating cell nuclear antigen staining demonstrated that hepatocyte proliferation markedly increased in rhHGF-treated rats as compared with controls. CONCLUSIONS: These results indicate that HGF facilitates recovery of the liver from hepatic WI/Rp injury, at least in part through the prevention of neutrophil infiltration and the activation of hepatocyte proliferation.

Animals↗
PubMed2000

Nitric oxide production and hepatic dysfunction in patients with postoperative sepsis.

1. Although hepatic function is well known to deteriorate following bacterial infection, the underlying mechanisms remain poorly understood. We have previously reported that nitric oxide (NO) radical leads to a decrease in the ketone body ratio (KBR) and in ATP content due to the inhibition of mitochondrial electron transport in primary cultured rat hepatocytes. 2. To evaluate the effects of NO radical on the liver in patients with postoperative sepsis, we analysed both the stable end-product of nitric oxide radical (NOx) as well as the arterial KBR (AKBR), which reflects liver tissue NAD+/NADH. 3. Twenty patients who had undergone general abdominal surgery and who developed postoperative sepsis were divided into two groups: (i) surviving; and (ii) non-surviving. Blood samples were collected before the development of postoperative sepsis and every 3 days until the patient either died or was discharged from hospital. 4. Plasma NOx levels in seven patients who subsequently died became progressively higher than those in the 13 surviving patients over the clinical course of postoperative sepsis. 5. In the non-surviving group, the AKBR was significantly lower than in surviving patients, indicating impaired hepatic function. In contrast, plasma NOx levels in non-surviving patients were significantly higher than in surviving patients. 6. Decreases in AKBR to levels below 0.7 in non-surviving patients followed high NOx levels. Moreover, plasma NOx levels were closely correlated with the AKBR, indicating that NO radical is associated with mitochondrial dysfunction in the liver. 7. It is likely that the overproduction of NO radical plays an important role in causing fatal metabolic disorders in patients with postoperative sepsis.

Aged↗
PubMed2000

Hypoxia and heat inhibit inducible nitric oxide synthase gene expression by different mechanisms in rat hepatocytes.

Ischemia/reperfusion contributes to the hepatic injury in resection and transplantation of the liver. However, the precise mechanisms involved in hypoxia stress remain to be clarified. Pro-inflammatory cytokines including interleukin 1beta (IL-1beta) induce a gene expression of inducible nitric oxide synthase (iNOS) and produce nitric oxide, which exerts either a cytoprotective or toxic effect. In this report, we found that hypoxia and heat markedly inhibited the induction of nitric oxide production stimulated by IL-1beta in rat cultured hepatocytes. Both treatments also abolished the induction of iNOS protein and mRNA. However, hypoxia could not prevent either degradation of an inhibitory protein (IkappaBalpha) of nuclear factor-kappaB (NF-kappaB) or translocation of NF-kappaB to the nucleus, whereas heat inhibited both of the IkappaBalpha degradation and NF-kappaB translocation. Transfection experiments with iNOS promoter construct revealed that hypoxia as well as heat significantly inhibited the transactivation of iNOS gene. Further, a hypoxia-response element located in the promoter was not involved in the inhibition of iNOS induction by hypoxia. These results indicate that hypoxia and heat suppress iNOS gene induction at the transcriptional level through different mechanisms. Reduction of nitric oxide production under hypoxic conditions may be implicated in the cellular damage or protection during hepatic ischemia/reperfusion.

Animals↗
PubMed2000

Increased extra domain-A containing fibronectin and hepatic dysfunction during septic response: an in vivo and in vitro study.

A massive inflammatory reaction resulting from systemic cytokine release is the common pathway underlying sepsis or multiple organ dysfunction. The role of extra domain sequence A-containing fibronectin (EDA+FN) formation during the septic response is not known. The present study investigates the role of EDA+FN during the septic response under in vitro and in vivo conditions. The direct effects of interleukin-1, interleukin-6, and tumor necrosis factor-alpha on EDA+FN production were evaluated in primary cultured human hepatocytes and fibroblasts. Serial plasma EDA+FN levels were measured using an enzyme-linked immunosorbent assay in 24 patients who developed postoperative sepsis following general abdominal surgery of which there were 17 survivors and 7 non-survivors. EDA+FN secretion was significantly increased in cultured hepatocytes but not fibroblasts at 24 and 48 h following exposure to IL-1 compared to controls. In the clinical setting plasma EDA+FN levels in non-survivors were significantly higher than in survivors. Moreover, the EDA+FN levels were correlated closely with liver function tests. EDA+FN levels may represent a specific marker of vascular injury or systemic inflammatory response syndrome that is associated with an adverse clinical outcome.

APACHE↗
PubMed1999

A novel conception for liver preservation at a temperature just above freezing point.

BACKGROUND: It is generally accepted that 0 to 4 degreesC is a suitable temperature for organ preservation. The reason for this is based on the premise that at temperatures below 0 degreesC, intracellular ice is likely to form, with subsequent damage to cellular structures. However, it cannot be assumed that subzero temperatures will freeze the cell. In this study, we attempted to confirm the specific freezing point of rat liver and to preserve it at a temperature just above that point. METHODS: Rat livers were stored for 24, 48, 72, and 96 h either at 4 degreesC (Group N) or at -0.8 degreesC (just above the temperature ascertained to be the specific freezing point of rat liver; Group H). After cold storage, the livers were perfused for 60 min using an isolated perfused liver model for assessment of liver function. RESULTS: ATP and TAN (total adenine nucleotides) in reperfused liver tissues were significantly higher in Group H than in Group N for all preservation periods. ADP was significantly higher in Group H than in Group N for 24-, 72-, and 96-h preservation periods. Energy charge was significantly higher in Group H than in Group N for 24-, 48-, and 96-h preservation periods. CONCLUSIONS: Regarding the content of ATP, ADP, and TAN and the adenylate energy charge, our results indicate that preservation at -0.8 degreesC is advantageous. This novel preservation technique seems to prolong the period that organs can be stored.

Adenine Nucleotides↗