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Biomedical subjects

D I Tai

Publications and source records attributed to D I Tai.

At least 19 recordsLinked to original sources
PubMed2001

Reappearance of HBsAg with compartmentalized different HBV strains in allograft versus PBMC of the recipient.

A woman who was positive for anti-hepatitis B surface antigen (anti-HBs) and anti-hepatitis B core antigen (anti-HBc) received an orthotopic liver transplantation from an anti-HBc-seropositive donor in November 1985. Reappearance of hepatitis B surface antigen (HBsAg) was noted 5 months after the transplantation, but it was not associated with significant liver inflammation. Ten years after the transplantation, results of serum hepatitis B virus (HBV) DNA study, by nested polymerase chain reaction, were negative. However, HBV DNA was detected in the transplanted liver tissues and peripheral blood mononuclear cells. Different strains were identified in these two organs. An adw strain was found in the transplanted liver, whereas an adr strain with long segment deletions in the core gene was found in the peripheral blood mononuclear cells. Covalently closed circular HBV DNA was not detected in any of the tissues examined. Occult HBV infection in the donor as well as the recipient is common in HBV endemic areas. The recipient in this case had reappearance of hepatitis B surface antigen (HBsAg) in the serum after transplantation. Nevertheless, 10 years later, two different strains of HBV were identified in different organs, without cross infection. The present case demonstrates that HBsAg reappearance was not associated with reactivation of the virus and liver inflammation. This type of HBsAg reappearance did not appear to produce a significant hazard to the transplanted liver.

Adult↗
PubMed2001

Apoptosis in viral hepatitis B and C.

Tumor necrosis factor (TNF) and TNF receptors (TNFR) are members of the growing TNF ligand and receptor families known to be involved in apoptosis, viral pathogenesis and immune regulation. The present report will focus on the role of apoptosis in the pathogenesis of viral hepatitis B and C. Although TNF was reported years ago to modulate viral infections, recent findings on the molecular pathways involved in TNFR signaling have allowed a better understanding of the molecular interactions between cellular and viral factors within the infected cell. The interactions of viral proteins with intracellular components downstream of the TNFR have highlighted at the molecular level that viruses can manipulate the cellular machinery to escape the immune surveillance and to favor spread infection. We will review here the mechanism of apoptosis and the role of viral proteins that regulate apoptosis in viral hepatitis B and C.

Apoptosis↗
PubMed2000

Constitutive activation of nuclear factor kappaB in hepatocellular carcinoma.

BACKGROUND: Nuclear factor kappaB (NF-kappaB) is a transcription factor that plays important roles in cell proliferation and in immunity against viral infections. NF-kappaB is a dimer of Rel proteins that is sequestered in the cytoplasm as an inactive form through interaction with an inhibitory kappaB (IkappaB) protein. When IkappaB is degraded, the NF-kappaB dimer will enter the nucleus to activate the target genes. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection may activate NF-kappaB and, thus, may modulate cell apoptosis and may be associated with oncogenesis. The role of NF-kappaB in hepatocellular carcinoma (HCC) has not yet been explored. METHODS: Immunohistochemical staining to search for active nuclear RelA and nuclear IkappaBalpha proteins were done on formalin fixed liver tissues from 65 patients with HCC and from 9 normal control participants. Nuclear extracts of fresh-frozen tumor and nontumor liver tissues from 37 patients with HCC and from 7 normal controls were tested for NF-kappaB-DNA binding activity by electrophoretic mobility shift assay. The RelA and IkappaBalpha protein expressions were studied by Western blot analysis. RESULTS: Nuclear NF-kappaB stainings were significantly more abundant in HBV-infected or HCV-infected tumors as well as nontumor parts of HCC compared with normal controls. Nuclear NF-kappaB DNA binding activity and nuclear RelA protein expression were greater in tumor tissue compared with nontumor tissue, whereas cytosolic IkappaBalphs protein expression was generally greater in nontumor tissue compared with tumor tissue. CONCLUSIONS: Constitutive activation of NF-kappaB was found more frequently in tumor tissue compared with nontumor tissue. It is possible that NF-kappaB overexpression accompanied by dysregulation of IkappaBalpha may play a role in the hepatocarcinogenesis of HBV or HCV infection.

Adult↗
PubMed2000

Identification and characterization of a prevalent hepatitis B virus X protein mutant in Taiwanese patients with hepatocellular carcinoma.

The aim of this study was to investigate whether there was a particular hepatitis B virus (HBV) X protein (HBx) mutant associated with Taiwanese patients with hepatocellular carcinoma (HCC). Initially, the entire coding region of HBx gene from the serum samples of 14 Taiwanese patients were sequenced. A novel mutant, HBx-A31, was preferentially found in patients with HCC. Sera from 67 patients with HCC and 100 patients with chronic hepatitis B were thus subjected for codon 31 analysis using a dual amplification created restriction site method. HBx-A31 was detected more frequently in patients with HCC (52% versus 12%; P<0.001) and in patients with liver cirrhosis (44% versus 6%; P<0.001). Site directed mutagenesis experiment revealed that HBx-A31 was less effective in transactivating HBV enhancer I-X promoter complex, less efficient in supporting HBV replication, and less potent in enhancing TNF-alpha induced increment of CPP32/caspase 3 activities in HepG2 cells. In conclusion, a prevalent HBx mutant was identified in Taiwanese patients with hepatocellular carcinoma. Development of this mutant might represent a strategy of the virus to escape immune surveillance and thus contribute to the process of multiple-step hepatocarcinogenesis.

Amino Acid Sequence↗
PubMed2000

Changes in portal venous hemodynamics in patients with severe acute hepatitis over one year.

PURPOSE: A wide range of portal vein blood flow velocity (PVV) values can be found in acute hepatitis. We studied course and medical significance of PVV changes in patients with severe acute hepatitis over a 1-year period. METHODS: Portal venous hemodynamics were studied by Doppler sonography in 90 patients at study enrollment and 3, 6, and 12 months following an episode of severe acute hepatitis. RESULTS: Forty-one survivors who had a maximum PVV at enrollment greater than or equal to the value measured at the third month were classified as the "declining PVV" group. Thirty-six survivors who had a maximum PVV at enrollment less than the value measured at the third month were classified as the "rising PVV" group. Thirteen patients died of acute hepatic failure and were classified as the fatality group. The fatality group had significantly lower maximum PVV, worse liver biochemical test results, and a higher prevalence of ascites at enrollment. In contrast, the declining PVV group showed significantly better liver biochemical test results and a lower prevalence of ascites. There was no significant difference in portal vein blood flow between the rising and declining PVV groups since portal vein diameter increased while PVV decreased. CONCLUSIONS: An initially decreased PVV can be found in some patients with severe acute hepatitis and is inversely correlated with the severity of liver damage.

Acute Disease↗
PubMed2000

Activation of nuclear factor kappaB in hepatitis C virus infection: implications for pathogenesis and hepatocarcinogenesis.

The hepatitis C virus (HCV) core protein is a multifunctional protein. It may bind to the death domain of tumor necrosis factor receptor 1 (TNFR1) and to the cytoplasmic tail of lymphotoxin-beta receptor, implying that it may be involved in the apoptosis and anti-apoptosis signaling pathways. In vitro studies have been inconclusive regarding its ability to inhibit or enhance TNF-alpha-induced apoptosis. To address this issue, electrophoretic mobility shift assay (EMSA) and immunohistochemical studies were used to show the activation of nuclear factor kappaB (NF-kappaB) in HCV-infected liver tissues and in HCV core-transfected cells. The activation of NF-kappaB was correlated with the apoptosis assays. The results showed that NF-kappaB activation could be shown in HCV-infected livers and HCV core-transfected cells. The data of EMSA correlated with those of immunohistochemical studies, which revealed a higher frequency of NF-kappaB nuclear staining in HCV-infected than in normal livers. NF-kappaB activation conferred resistance to TNF-alpha-induced apoptosis in HCV core-transfected cells. Inhibition of NF-kappaB activation by pyrrolidine dithiocarbamate sensitized them to TNF-alpha-induced apoptosis. These findings suggest that HCV infection may cause anti-apoptosis by activation of NF-kappaB and implicate a mechanism by which HCV may evade the host's immune surveillance leading to viral persistence and possibly to hepatocarcinogenesis.

Adult↗
PubMed2000

Effects of extended lamivudine therapy in Asian patients with chronic hepatitis B. Asia Hepatitis Lamivudine Study Group.

BACKGROUND & AIMS: One-year lamivudine therapy significantly suppressed hepatitis B virus (HBV) replication, improved hepatic necroinflammatory activity, and prevented progression of fibrosis. However, the effects of prolonged therapy are unknown. METHODS: A total of 334 Asian patients with chronic hepatitis B from a previously reported 1-year study were randomized to receive either lamivudine (100 or 25 mg) or placebo for another year. The effects of treatment on serum HBV-DNA suppression, alanine transaminase (ALT) normalization, and hepatitis B e antigen (HBeAg) seroconversion were measured. The presence of YMDD variant HBV and its effect were also determined. RESULTS: A significantly greater proportion of patients achieved sustained HBV-DNA suppression and ALT normalization with 100 mg lamivudine daily for 2 years compared with lamivudine for 1 year followed by placebo for the second year (P<0.001). Daily lamivudine therapy for 2 years was safe and resulted in incremental HBeAg seroconversion from 17% at week 52 to 27% at week 104. HBeAg seroconversion during continued lamivudine therapy increased linearly with increasing pretherapy ALT levels (P< 0.001). Despite the emergence of YMDD mutant in 38% of the patients, they continued to clear serum HBeAg and maintain lower median serum HBV-DNA and ALT levels than baseline values. In contrast, ALT levels increased 8-12 weeks after switching from lamivudine to placebo, but returned to normal once lamivudine treatment was resumed. CONCLUSIONS: Treatment with lamivudine for 2 years is both well tolerated and efficacious in patients with chronic hepatitis B.

Adult↗
PubMed1999

Replication of hepatitis B virus in first-degree relatives of patients with hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) may occur in family clusters. No genetic mechanism has been identified as responsible for this familial tendency. We suspected that a longer hepatitis B virus (HBV) replication phase might be the reason for a higher risk of HCC in families with this disease. We performed liver biochemical tests, test for viral hepatitis markers and hepatitis B e antigen (HBeAg), and liver ultrasonography in relatives of patients with HCC. A total of 1,885 first-degree relatives from 688 families participated in this study. Seven hundred fifty-two relatives were found to be carriers of hepatitis B surface antigen (HBsAg) and 675 of them were tested for HBeAg. The prevalence of HBeAg was 27.4% in relatives of those with HCC and 20% in asymptomatic HBsAg carriers. The HBeAg prevalence rate was higher in relatives of those with HCC > or = 40 years old than in asymptomatic HBsAg carriers. Moreover, HBeAg was more likely to persist in men than in women > or = 40 years old. We conclude that families with HCC showed a prolonged HBV replication phase that may be one of the cofactors for a familial tendency for HCC.

Adolescent↗
PubMed1998

A one-year trial of lamivudine for chronic hepatitis B. Asia Hepatitis Lamivudine Study Group.

BACKGROUND AND METHODS: In preliminary trials, lamivudine, an oral nucleoside analogue, has shown promise for the treatment of chronic hepatitis B. We conducted a one-year, double-blind trial of lamivudine in 358 Chinese patients with chronic hepatitis B. The patients were randomly assigned to receive 25 mg of lamivudine (142 patients), 100 mg of lamivudine (143), or placebo (73) orally once daily. The patients underwent liver biopsies before entering the study and after completing the assigned treatment regimen. The primary end point was a reduction of at least two points in the Knodell necroinflammatory score. RESULTS: Hepatic necroinflammatory activity improved by two points or more in 56 percent of the patients receiving 100 mg of lamivudine, 49 percent of those receiving 25 mg of lamivudine, and 25 percent of those receiving placebo (P<0.001 and P=0.001, respectively, for the comparisons of lamivudine treatment with placebo). Necroinflammatory activity worsened in 7 percent of the patients receiving 100 mg of lamivudine, 8 percent of those receiving 25 mg, and 26 percent of those receiving placebo. The 100-mg dose of lamivudine was associated with a reduced progression of fibrosis (P=0.01 for the comparison with placebo) and with the highest rate of hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg, development of antibody to HBeAg, and undetectable HBV DNA) (16 percent), the greatest suppression of HBV DNA (98 percent reduction at week 52 as compared with the base-line value), and the highest rate of sustained normalization of alanine aminotransferase levels (72 percent). Ninety-six percent of the patients completed the study. The incidence of adverse events was similar in all groups, and there were few serious events. CONCLUSIONS: In a one-year study, lamivudine was associated with substantial histologic improvement in many patients with chronic hepatitis B. A daily dose of 100 mg was more effective than a daily dose of 25 mg.

Adolescent↗
PubMed1997

Endoscopic injection sclerotherapy with 1.5% Sotradecol for bleeding cardiac varices.

The authors retrospectively studied the efficacy of endoscopic injection sclerotherapy (EIS) with 1.5% Sotradecol (STD) in patients with bleeding cardiac varices (CV). Case histories of 27 patients with large, isolated, bleeding CVs were reviewed. Case records of another 27 patients with isolated esophageal varices (EV), matched for age, sex, and year EIS was performed, were selected from a computer data bank as controls. Using a small volume (2-4 ml) of injection per vessel, the rate of immediate control of bleeding was 66.7% (18 of 27) in the CV group and 70.4% (19 of 27) in the EV group. The early rebleeding rate was higher for patients in the EV group (48.1%, 13 of 27) than for those in the CV group (18.5%, 5 of 27) (p = 0.0209). On the other hand, it was more difficult to control the rebleeding from CV (p = 0.00494). In terms of mortality, there was no statistically significant difference between the CV and EV groups (33.3 versus 29.6%) within 1 week after EIS, but the 1-month post-EIS mortality rate was significantly higher (p = 0.0278) in the CV group (18 of 27, 66.7%) than in the EV group (10 of 27, 37.0%). Among those in the CV group who died of late complications within 1 month after EIS, three died of recurrent hemorrhage, five of infection, and one of viscus perforation. In the EV group, only two patients died of infection. Thus, it was concluded that EIS with small volumes (2-4 ml) of 1.5% STD was equally effective in controlling immediate bleeding from CV and EV. However, it was more difficult to control early rebleeding from CV, and the mortality and complications within 1 month after EIS were significantly higher in patients with CV. These observations are currently under careful study and evaluation.

Adult↗
PubMed1996

Inter-observer variability of portal hemodynamics measured by Doppler ultrasound on three different locations of portal vein.

Doppler ultrasound is a noninvasive modality for portal hemodynamic study. However, inter-observer variability has been observed. This study has investigated ways to produce less inter-observer variability. Doppler ultrasound portal vein hemodynamic studies were carried out by three well-trained specialists on 20 healthy hospital staff members. The intra-hepatic, first branch, right portal vein, the hilar portal vein, and the extra-hepatic portal vein were chosen for study. With respect to the diameter of portal veins, a significant inter-observer variability was found for the first branch right portal vein and the extra-hepatic portal vein, but not for the hilar portal vein. For maximal portal vein velocity studies, inter-observer variability was not found at any location. A significant failure rate was noted for the measurement of extra-hepatic portal vein velocity. Only 8 volunteers had complete data from all of the three investigators. A significant variability was also noted for the average velocity of extra-hepatic portal vein. We conclude that Doppler ultrasound hemodynamic studies of the hilar portal vein has the most acceptable inter-observer variability and thus should be used for longitudinal portal hemodynamic studies.

Adult↗
PubMed1995

Success of endoscopic injection therapy in correlation with maximal one-day transfusion requirement.

BACKGROUND AND STUDY AIMS: The rate of blood transfusion is related to blood flow and the diameter of the bleeding vessel. Therapeutic endoscopy is less effective in larger vessels. To determine the effect of therapeutic endoscopy with pure ethanol injection in massive peptic ulcer bleeding, we conducted a retrospective study using the maximal one-day blood requirement as an indicator of the required blood transfusion. PATIENTS AND METHODS: The maximal one-day blood requirement was defined as the total amount of blood transfusion needed within a day to keep hemodynamics stable and hemoglobin above 8.0 g% before therapeutic endoscopy. From January 1986 to May 1993, 283 patients with high-risk signs of the stigmata of hemorrhage on endoscopy, who received pure ethanol injection therapy, were included in this study. There were 214 men and 69 women with a mean age of 58.4 years (ranging from 16 to 93 years). One hundred forty-three had gastric ulcers; 125 had duodenal ulcers; and 15 had stomal ulcers. Patients whose maximal one-day blood requirement was less than 1000 ml were assigned to Group I. Patients without, and patients with, major organ diseases whose maximal one-day blood requirement was more than 1000 ml were assigned to Group IIa and Group IIb, respectively. RESULTS: In Group I, 87.1% attained permanent hemostasis; 51.3% in Group IIa; and 49.4% in Group IIb. Temporary hemostasis and failure rates were 8.9% and 4.8% in Group I; 14.5% and 33.8% in Group IIa; and 21.2% and 29.4% in Group IIb. The rate of permanent hemostasis was significantly lower in patients with massive bleeding (p < 0.001) but did not differ between patients with and without major organ diseases (p > 0.05). CONCLUSION: The success rate for pure ethanol injection therapy was lower in patients with a large maximal one-day blood transfusion requirement.

Adolescent↗
PubMed1995

Septic acute cholecystitis.

BACKGROUND: Bacteremia occurs frequently in cholangitis, but the incidence of bacteremia in acute cholecystitis has not previously been examined. METHODS: Seventy-eight cases (46 men and 32 women; mean age, 63 +/- 10 years) of acute cholecystitis with positive blood cultures were analyzed for clinical manifestation, bacteriology, and what consequences ensued. Seventy-eight non-bacteremic cholecystitis patients, matched for age and sex, served as the control group. RESULTS: The prevalence of bacteremia in acute cholecystitis was 7.65% (78 of 1020). A single microorganism was isolated from the blood and bile in 87.2% and 27.3%, respectively. The commonest organisms were Escherichia coli and Klebsiella pneumoniae. The source of bacteremia could be identified from the infected bile in 80% of cases. Compared with the non-bacteremia group, significant increases in liver biochemical test results (aspartate and alanine aminotransferases and bilirubin, and so forth), more complications (acute renal failure and septic shock), and higher mortality (9.0%) were found in the bacteremic group. CONCLUSION: Acute cholecystitis is not often complicated by bacteremia, but when bacteremia is present, morbidity and death more consistently ensue.

Acute Disease↗
PubMed1995

[Small cell lung cancer with liver and bone metastasis associated with hypercalcemia and acute pancreatitis--a case report].

A 67-year-old man was hospitalized with the chief complaint of diffuse abdominal pain for 3 days. Hypercalcemia and acute pancreatitis was found by laboratory examination. Abdominal CT scans showed swelling of the pancreas, multiple liver tumors and osteolytic lesions of bone. Upper mediastinal lobulated mass was suspected from chest x-ray examination, then small cell lung cancer (SCLC) was proved by bronchoscopic and pathological examination. The final diagnosis is SCLC with liver and bone metastasis associated with hypercalcemia and acute pancreatitis. After pancreatitis subsided, the patient was put on chemotherapy. Unfortunately, due to immunocompromise, he died of pneumonia and sepsis. There was no reasonable explanation regarding to the cause of acute pancreatitis except hypercalcemia, which might be due to SCLC with bone metastasis. This is the first report of such a complication in a patient with SCLC.

Acute Disease↗
PubMed1995

Hepatobiliary imaging of functional and morphological changes following hepatic arterial embolization in hepatocellular carcinoma.

UNLABELLED: Hepatic arterial embolization (HAE) is the treatment of choice for inoperable hepatocellular carcinoma. There are functional changes following HAE in the tumor and in the adjoining normal liver and biliary structures. We sought to determine if a 99mTc-HIDA hepatobiliary scan could evaluate the morphological and functional changes of the liver and biliary systems in patients with hepatocellular carcinoma undergoing HAE. METHODS: Patients with hepatoma were evaluated by 99mTc-HIDA hepatobiliary scans before and after HAE. RESULTS: Ten patients with histologically proven hepatomas had 44 99mTc-HIDA scans over a 319-mo period. Liver uptake was good in all patients, none developed hepatic failure. Liver tumors were detected in five of the eight studies done before the first HAE. The HIDA scan failed to locate the tumor throughout the whole study period in only one patient. Two patients showed evidence of tumor uptake of the HIDA agent. In one of these two patients the hot uptake disappeared after the HAE but reappeared after tumor recurrence. Gallbladder filling time and contractility worsened in all eight patients the day after embolization. On the HIDA scans, the gallbladder was not visualized in three of four patients who survived longer than 40 mo after HAE. Bile stasis in the left intrahepatic duct was found in six of the eight patients who survived longer than 8 mo after HAE. CONCLUSIONS: Biliary complications were common in patients who received HAE, and HIDA scans may be useful for evaluating the biliary system and hot uptake in hepatocellular carcinoma in candidates for HAE.

Adult↗