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1.
Transplant Proc ; 50(9): 2675-2678, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30401375

ABSTRACT

OBJECTIVE: The purpose of this study is to evaluate the use of diffusion-weighted magnetic resonance imaging (DWMRI) in the assessment of graft rejection after liver transplantation (LT). METHODS: From June 2017 to January 2018, 32 patients were included in the study with a mean age of 52.3 years. All patients underwent LT. The DWMRI was performed using the apparent diffusion coefficient map and measuring the different b-values (b-400, b-600, b-800, and b-1000). These measurements were compared with the histopathology results. Statistical analysis included t test, analysis of variance, and area under the curve for receiver operating characteristic (ROC). RESULTS: There were 17 patients without rejection and 15 patients with liver graft rejection diagnosed by histopathology. The mean (SD) results between the nonrejection and rejection groups were as follows: b-400 = 1.568 (0.265) vs 1.519 (0.119) (P = .089), b-600 = 1.380 (0.181) vs 1.284 (0.106) (P = .039), b-800 = 1.262 (0.170) vs 1.170 (0.086) (P = .035), b-1000 = 1.109 (0.129) vs 1.098 (0.078) (P = .095); B-values × 10-3 mm2/s. Only b-600 (P = .04) and b-800 (P = .04) values have significant differences between the 2 groups. B-600 showed 90.48% sensitivity and 83.33% specificity (ROC area under the curve = 0.784; P < .001), and b-800 showed 90.38% sensitivity and 83.03% specificity (ROC area under the curve = 0.816; P < .001). The values obtained with the apparent diffusion coefficient in b-800 were clearly differentiated between the mild, moderate, and severe degrees of rejection (P < .001). CONCLUSION: Measurement of b-600 and b-800 values using DWMRI may be used for the diagnosis of graft rejection after LT.


Subject(s)
Diffusion Magnetic Resonance Imaging/methods , Graft Rejection/diagnostic imaging , Liver Transplantation/adverse effects , Liver/diagnostic imaging , Adult , Aged , Female , Humans , Male , Middle Aged , ROC Curve , Sensitivity and Specificity
2.
Transplant Proc ; 48(4): 1003-6, 2016 May.
Article in English | MEDLINE | ID: mdl-27320542

ABSTRACT

OBJECTIVE: The purpose of this study is to evaluate the accuracy rate of the one breath-hold single voxel hydrogen-1 magnetic resonance spectroscopy (MRS) in comparison with intraoperative biopsy for liver fat quantification in living-donor liver transplantation. MATERIALS AND METHODS: A total of 80 living liver donors participated in this study. Each patient underwent both MRS and intraoperative biopsy for evaluation of liver fatty content. MRS was performed using 1.5-T magnetic resonance imaging and placed in segments 2-4, 5-8, and left lateral segment for each donor. Accuracy was assessed through receiver operating characteristic curve analysis. Sensitivity and specificity of MRS fat fractions were also calculated. RESULTS: Eighty living-donor liver transplantation donors were enrolled in this study. There was no fatty liver in 59 subjects (73.8%), 5% to 10% fatty liver in 17 subjects, 11% to 15% fatty liver in 3 subjects, and >16% fatty liver in 1 subject. MRS fat fraction showed excellent parameters to predict between normal liver and fatty liver groups (1.85% ± 0.98, 8.13% ± 3.52, respectively; P < .0001). Linear regression between MRS fat fraction and pathology grading showed high correlation (R(2) = 0.7092). Pearson correlation revealed high correlation between MRS and pathology results (r = 0.936), poor correlation between body mass index and pathology results (r = 0.390). The sensitivity and specificity for detection of liver steatosis in MRS fat fraction were 95.2% and 98.3%, respectively. CONCLUSION: (1)H MRS fat fraction is a highly precise and accurate method in quantification of hepatic steatosis for the living donor and can be finished in a single breath-hold.


Subject(s)
Fatty Liver/pathology , Liver Transplantation/methods , Liver/pathology , Living Donors , Adolescent , Adult , Biopsy , Female , Humans , Magnetic Resonance Imaging/methods , Magnetic Resonance Spectroscopy/methods , Male , Middle Aged , Prospective Studies , ROC Curve , Sensitivity and Specificity , Young Adult
3.
Transplant Proc ; 48(4): 1041-4, 2016 May.
Article in English | MEDLINE | ID: mdl-27320551

ABSTRACT

OBJECTIVE: Liver transplantation for intrahepatic cholangiocarcinoma is notorious for rapid recurrence with poor survival rate postoperatively and has therefore been discontinued in most centers. The purpose of this study is to distinguish hepatocellular carcinoma (HCC) from cholangiocarcinoma in pretransplantation imaging evaluation by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). MATERIALS AND METHODS: From January 2014 to September 2015, 19 patients were included in the study, with a mean age of 62.8 years. All subjects underwent pretransplantation DCE-MRI and surgical excision or core biopsy. The DCE-MRI parameters were measured using the Tofts model 1999. Statistical analysis included nonparametric tests and area under the curve for the receiver operating characteristic. RESULTS: Fourteen HCCs and 5 cholangiocarcinomas were diagnosed by surgical pathology. The mean size of tumor was 6.4 cm (range, 1.5 cm to 13.7 cm). All DCE-MRI parameters were calculated as the ratio between the tumor and normal liver parenchyma and K(trans) (1/min) was used as a distinguishing parameter between the two tumors. K(trans) was higher in the cholangiocarcinoma group (1.89 ± 1.13) than in the HCC group (0.46 ± 0.35). Univariate analysis revealed that K(trans) has a high significant difference (P = .001). The optimal K(trans) value cutoffs were 1 or more (area under the curve = 0.971) for detection of HCCs or cholangiocarcinomas. CONCLUSION: The analysis of DCE-MRI with the kinetic model (Tofts, 1999) presents a new and practical approach indiscrimination of HCC from cholangiocarcinoma for pretransplantation imaging evaluation.


Subject(s)
Bile Duct Neoplasms/diagnostic imaging , Carcinoma, Hepatocellular/diagnostic imaging , Cholangiocarcinoma/diagnostic imaging , Contrast Media/pharmacokinetics , Liver Neoplasms/diagnostic imaging , Magnetic Resonance Imaging/methods , Adult , Aged , Bile Duct Neoplasms/metabolism , Bile Ducts, Intrahepatic/diagnostic imaging , Bile Ducts, Intrahepatic/metabolism , Carcinoma, Hepatocellular/metabolism , Cholangiocarcinoma/metabolism , Diagnosis, Differential , Female , Humans , Liver/diagnostic imaging , Liver/metabolism , Liver Neoplasms/metabolism , Liver Transplantation , Male , Middle Aged , ROC Curve
4.
Transplant Proc ; 46(3): 666-8, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24767318

ABSTRACT

OBJECTIVE: Hepatic steatosis can cause substantial problems for both donors and recipients in living donor liver transplantation (LDLT). The aim of this study is to evaluate the accuracy of the magnetic resonance IDEAL (iterative decomposition of water and fat with echo asymmetry and least squares estimation) sequence in quantifying the liver fat during LDLT. MATERIALS AND METHODS: A total of 63 liver donors (29 men and 34 women ranging from 18 to 47 years old with a mean age of 30) who received both magnetic resonance imaging (MRI) and intraoperative liver biopsy were enrolled in this study. MR IDEAL IQ sequences were performed by 1.5-T MRI (Discovery 450; GE Healthcare, Milwaukee, Wis, United States) to estimate the liver fatty content. Accuracy was assessed through linear regression between fat fraction image and pathology grading. Sensitivity and specificity of MR IDEAL IQ fat fractions were also calculated. RESULTS: A total of 63 LDLTs were performed and with pathology grading. No fatty content was found in 48 donors (76.2%; group 1), 5% to 10% fatty liver in 11 donors (17.4%; group 2), 11% to 15% fatty liver in 2 donors (3.2%; group 3), and >16% fatty change in 2 donors (3.2%; group 4). MR IDEAL fat fraction results were excellent in prediction of the normal and fatty content and with good correlation with the pathology grading (2.9 ± 0.9, 8.3 ± 4.2, P < .0001). Linear regression between IDEAL image and pathology grading indicated a high accuracy rate (R(2) = 0.813, R(2) = 0.9286) for all 4 groups. The sensitivity and specificity for detection of liver steatosis in MRI fat fraction image were 100% and 77.1% (P < .0001, 95% confidence interval 0.000-1.000). CONCLUSION: MR IDEAL IQ sequencing is a highly precise and accurate method in quantifying hepatic steatosis for the living donor.


Subject(s)
Adipose Tissue/pathology , Liver Transplantation , Liver/pathology , Living Donors , Magnetic Resonance Imaging/methods , Adolescent , Adult , Female , Humans , Male , Middle Aged , Young Adult
5.
Transplant Proc ; 44(2): 324-7, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22410007

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the image quality and diagnostic accuracy of postgadolinium complex of diethylenetriaminepentaacetic acid (GD-DTPA)-enhanced magnetic resonance cholangiography (MRC) in donor selection. MATERIALS AND METHODS: Donors (n=228) with both preoperative MRC and intraoperative cholangiography (IOC) were enrolled in this study. MRC pre- and post-GD-DTPA enhancement were performed using 1.5-T magnetic resonance imaging. The signal-to-noise ratio (SNR) of liver parenchyma and contrast-to-noise ratio of bile duct, as well as the contrast between bile duct and liver parenchyma, were calculated. The biliary anatomy correlation with the IOC during hepatectomy and patient prognosis were also evaluated. RESULTS: Quantitative results of the SNR of the liver parenchyma post-GD-DTPA were statistically significantly lower than preenhanced MRC (2.69 times reduced from the preenhanced MRC). The contrast of the bile duct and liver parenchyma in post-GD-DTPA were significantly higher than the preenhancement MRC. The anatomic diagnostic accuracy rate of post-GD-DTPA MRC was 92.9%. The sensitivity and specificity of GD-PTPA MRC were 85% and 96%, respectively. GD-DTPA-enhanced MRC has higher accuracy than the preenhanced MRC (92.9% vs 75%). The concurrence between GD-DTPA-enhanced MRC and IOC were commendable (kappa=0.9). The posttransplant biliary complication rate was 5.5%, and the 3-year survival rate was 91.2% in the recipients. CONCLUSION: GD-DTPA, a paramagnetic metal, can shorten the T1 and T2 relaxation values of surrounding protons. This decreases the signal of the liver parenchyma and brightens the biliary anatomy. It can improve the image quality of MRC and increase the diagnostic accuracy of the biliary tract classification. It is mandatory in the "donor and recipient surgery during the LDLT".


Subject(s)
Cholangiography/methods , Contrast Media , Donor Selection , Gadolinium DTPA , Hepatectomy , Liver Transplantation , Liver/surgery , Living Donors , Magnetic Resonance Imaging , Adolescent , Adult , Biliary Tract/anatomy & histology , Biliary Tract/injuries , Female , Hepatectomy/adverse effects , Humans , Liver/anatomy & histology , Liver Transplantation/adverse effects , Liver Transplantation/mortality , Magnetic Resonance Imaging, Interventional , Male , Middle Aged , Predictive Value of Tests , Preoperative Care , Sensitivity and Specificity , Signal-To-Noise Ratio , Survival Analysis , Taiwan , Time Factors , Treatment Outcome , Wounds, Penetrating/etiology , Wounds, Penetrating/prevention & control , Young Adult
6.
Int J Tuberc Lung Dis ; 15(4): 471-7, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21396205

ABSTRACT

OBJECTIVE: To estimate the tuberculosis (TB) burden in Taiwan from 1996 to 2006, based on incidence, mortality and disability-adjusted life years (DALYs). DESIGN: Data were collected from three databases: Tuberculosis Registry Database, National Mortality Database and Taiwan Household Registration System Database. Age standardisation of the incidence/mortality rates was performed by the direct method, using the 2000 World Health Organization world population as standard. Disease burden estimation used DALY, based on the Global Burden of Disease study. RESULTS: The age-adjusted TB incidence/mortality rates decreased during the study period. The highest DALYs per 100,000 were in the ≥65 years age group among non-aboriginals, and in the 35-54 years and ≥65 years age groups in aboriginals. In general, the DALY/case increased with age among non-aboriginals, whereas the highest DALY/case was found in the 35-44 years age group in aboriginals. The DALY/100,000, DALY/case and total DALY significantly decreased from 1996 to 2006 for non-aboriginals, but fluctuated for aboriginals. CONCLUSION: This analysis provided the first comprehensive evaluation of the burden of TB in Taiwan. The prevention and treatment of TB among aboriginals in all age groups should be enhanced.


Subject(s)
Asian People/statistics & numerical data , Cost of Illness , Quality-Adjusted Life Years , Tuberculosis/ethnology , Tuberculosis/epidemiology , Adolescent , Adult , Age Distribution , Aged , Child , Child, Preschool , Databases, Factual , Female , Humans , Infant , Male , Middle Aged , Registries , Taiwan/epidemiology , Tuberculosis/mortality , World Health Organization , Young Adult
7.
J Biochem ; 130(5): 627-35, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11686925

ABSTRACT

In Escherichia coli, biotin synthase (bioB gene product) catalyzes the key step in the biotin biosynthetic pathway, converting dethiobiotin (DTB) to biotin. Previous studies have demonstrated that BioB is a homodimer and that each monomer contains an iron-sulfur cluster. The purified BioB protein, however, does not catalyze the formation of biotin in a conventional fashion. The sulfur atom in the iron-sulfur cluster or from the cysteine residues in BioB have been suggested to act as the sulfur donor to form the biotin molecule, and yet unidentified factors were also proposed to be required to regenerate the active enzyme. In order to understand the catalytic mechanism of BioB, we employed an approach involving chemical modification and site-directed mutagenesis. The properties of the modified and mutated BioB species were examined, including DTB binding capability, biotin converting activity, and Fe(2+) content. From our studies, four cysteine residues (Cys 53, 57, 60, and 97) were assigned as the ligands of the iron-sulfur cluster, and Cys to Ala mutations completely abolished biotin formation activity. Two other cysteine residues (Cys 128 and 188) were found to be involved mainly in DTB binding. The tryptophan and histidine residues were suggested to be involved in DTB binding and dimer formation, respectively. The present study also reveals that the iron-sulfur cluster with its ligands are the key components in the formation of the DTB binding site. Based on the current results, a refined model for the reaction mechanism of biotin synthase is proposed.


Subject(s)
Biotin/metabolism , Escherichia coli/enzymology , Iron-Sulfur Proteins/metabolism , Sulfurtransferases/metabolism , Amino Acid Sequence , Binding Sites , Biotin/analogs & derivatives , Cysteine/metabolism , Dimerization , Enzyme Activation , Iron-Sulfur Proteins/chemistry , Iron-Sulfur Proteins/genetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Sequence Homology, Amino Acid , Structure-Activity Relationship , Sulfurtransferases/chemistry , Sulfurtransferases/genetics
8.
J Formos Med Assoc ; 97(1): 73-5, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9481071

ABSTRACT

Renal subcapsular abscess is a very rare disease that is defined by a suppurative process localized to a space between the renal capsule and the renal parenchyma. The course and management of subcapsular abscesses have received less attention than those of renal and perirenal abscesses. We describe a 63-year-old diabetic woman who presented with intermittent fever of 1 month's duration. She was initially treated for suspected acute pyelonephritis then referred to our hospital because of poor clinical response to cefazolin plus gentamicin. Computed tomography of the abdomen revealed a huge subcapsular abscess with displacement and compression of the left renal parenchyma. A percutaneous catheter was inserted and left in place for 8 days; a total of approximately 850 mL of pus was drained. Culture of the pus yielded Klebsiella pneumoniae and Enterobacter cloacae. A 2-week course of moxalactam was administered on the basis of the results of in vitro antibiotic susceptibility testing. The distorted renal parenchyma appeared normal at sonographic follow-up examination 3 weeks after hospitalization. The course and management of this rare entity are presented as a reminder to physicians that renal subcapsular abscess could manifest as fever of unknown origin in a diabetic patient. A high degree of clinical suspicion is required for early diagnosis and treatment in order to achieve a satisfactory outcome.


Subject(s)
Abscess , Diabetic Nephropathies , Enterobacter cloacae , Enterobacteriaceae Infections , Klebsiella Infections , Klebsiella pneumoniae , Pyelonephritis , Abscess/diagnosis , Abscess/drug therapy , Abscess/microbiology , Diabetic Nephropathies/diagnosis , Diabetic Nephropathies/drug therapy , Diabetic Nephropathies/microbiology , Enterobacteriaceae Infections/diagnosis , Enterobacteriaceae Infections/drug therapy , Female , Humans , Klebsiella Infections/diagnosis , Klebsiella Infections/drug therapy , Middle Aged , Pyelonephritis/diagnosis , Pyelonephritis/drug therapy , Pyelonephritis/microbiology
9.
J Neuroimmunol ; 80(1-2): 13-22, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9413255

ABSTRACT

We analyzed myelin basic protein (MBP) specific T cell hybridoma clones from (B10.PL x PL/J)F1 mice. MBP-reacting T cell hybridomas from F1 mice preferentially expressed B10.PL TcraV2.3 (53%) and B10.PL TcraV4.2 (13%) with minor expression of TcraV4.4 (13%) gene segments. A dominant expression of TcrbV8.2 (73%) accompanying with TcrbV8.1 (20%) and TcrbV13 (7%) gene segments have been identified in these MBP-reacting T cell hybridomas from F1 mice. There was less restrictive but non-random usage of the TcraJ and TcrbJ gene segments. Overall, the MBP-reacting T cell hybridomas from (B10.PL x PL/J)F1 mice were dominated by the MBP-reacting T cell pattern seen in B10.PL mice.


Subject(s)
Gene Rearrangement, T-Lymphocyte/immunology , Genes, T-Cell Receptor/immunology , Myelin Basic Protein/genetics , T-Lymphocytes/metabolism , Amino Acid Sequence , Animals , Base Sequence , Crosses, Genetic , Flow Cytometry , Gene Expression Regulation/immunology , Hybridomas , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Multigene Family , Myelin Basic Protein/immunology , Myelin Basic Protein/metabolism , Rats , Receptors, Antigen, T-Cell, alpha-beta/biosynthesis , Receptors, Antigen, T-Cell, alpha-beta/genetics , Species Specificity
10.
Zhonghua Yi Xue Za Zhi (Taipei) ; 60(5): 265-72, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9509682

ABSTRACT

BACKGROUND: Complicated pancreatic inflammatory diseases are often life-threatening, multifocal, and multibacterial disorders. Untreated, these lesions often prove fatal. The purpose of the study is to describe interventional radiologic techniques for diagnosis and treatment of complicated peripancreatic fluid collections. METHODS: Between January 1994 and December 1995, 17 patients with abdominal fluid collection from complicated acute pancreatitis underwent percutaneous drainage following initial diagnosis with computed tomography (CT). These patients required multiple CT examinations, multiple catheter insertions, multiple catheter manipulations, and long-term catheter drainage. RESULTS: Twenty-five infected fluid collections among these 17 patients were percutaneously drained. Sixteen (94%) patients were successfully treated with catheter drainage alone. Surgical treatment was necessary in one patient because of segmental stricture of transverse colon caused by inflammation and adhesion of transverse mesocolon. Catheter drainage duration averaged 31 days. Patients required an average of three catheter manipulations and four abdominal CT scans. Mean hospital stay was 42 days (range, 11-95 days), and mean ICU stay was 25 days (range, 1-70 days). CONCLUSIONS: The study confirms that complicated peripancreatic fluid collections can be safely and effectively treated in most patients with percutaneous catheter technique.


Subject(s)
Abscess/therapy , Drainage , Pancreatitis/complications , Acute Disease , Adult , Aged , Catheterization , Female , Humans , Male , Middle Aged
13.
Article in English | MEDLINE | ID: mdl-7618466

ABSTRACT

BACKGROUND: The objective of this study is to reassess the validity of plain film diagnosis for pediatric intussusception with consideration of the combinations of radiologic findings. METHODS: Sixty-six cases of intussusception and 81 controls of gastroenteritis were collected. Their films were read blindly by three radiologists together, with emphasis on nine radiologic findings: sparse colon gas (F1), sparse fecaloid content in colon (F2), gas-filled small bowel loops in right hypochondrium (F3), small bowel obstruction (F4), difficulty in assessing cecum position (F5), pneumoperitoneum (F6), discernible mass lesion (F7), target sign (F8) and crescent sign (F9). The sensitivity and specificity of individual findings and combinations of findings were analyzed. RESULTS: No cases showed F6. Listed in decreasing order of sensitivity, the other eight findings were F1, F5, F2, F7, F3, F4, F9 and F8. The sensitivity and specificity of these eight findings were inversely proportional with significant p-values (F8: < 0.005; the other seven findings: < 0.001). Sixty-three films (95%) in case group displayed combination of at least three radiologic findings. If the diagnostic criteria must consist of at least three radiologic findings, 60 cases (74%) of control group can be excluded. CONCLUSIONS: After eliminating the confounding effect of small bowel obstruction on the percentage of gas-filled small bowel loops in right hypochondrium and excluding the data agreed by only one radiologist from the study by Ratcliffe et al, the results of plain film findings were consistent with those of previous reports. The plain abdominal film can play an active role in the diagnosis of pediatric intussusception. Its validity increases when combinations of radiologic findings rather than individual signs are emphasized.


Subject(s)
Gastroenteritis/diagnostic imaging , Intussusception/diagnostic imaging , Adolescent , Child , Child, Preschool , Diagnosis, Differential , Female , Humans , Infant , Male , Predictive Value of Tests , Radiography , Retrospective Studies , Sensitivity and Specificity , X-Ray Film
14.
Zhonghua Yi Xue Za Zhi (Taipei) ; 54(5): 343-8, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7834557

ABSTRACT

BACKGROUND: Bile duct stone is a common biliary tract disease in Taiwan. Surgery and choledochoscopy are the current methods of treatment. This is a retrospective review of 65 cases who were admitted with postoperative biliary residual stones, or cholangitis secondary to the biliary stones. Percutaneous biliary stone removals under fluoroscopy were attempted. METHODS: Either a T-tube tract or percutaneous transhepatic cholangial drainage tract or both were used for stone removal. Angiographic superselective catheterization technique was applied for superselective cholangiography to identify the location of stones and to deliver basket and electrohydraulic lithotripsy probe to the site of the stones. Balloon dilation was applied for biliary stricture. RESULTS: Most of the cases needed multiple sessions (four, on an average) to remove all stones. There were 52% of the cases who needed balloon dilation for associated biliary strictures, and 7.7% of the cases had residual stones at the end of the procedure, because of technical difficulties. Chills and fever, pancreatitis, hepatic arterial injury and perforation of the common bile duct were procedure-related complications. In follow-up studies, 15% of the cases had recurrent biliary stones and 4.6% of the patients expired from malignant biliary tumors. CONCLUSIONS: Percutaneous biliary stone removal under fluoroscopy is beneficial for direct visualization of the location and number of the stones, and the architectural changes of the bile ducts. Superselective catheterization and balloon dilation were responsible for the high success rate (92.5%) here.


Subject(s)
Cholelithiasis/surgery , Adolescent , Adult , Aged , Bile Duct Diseases/surgery , Female , Fluoroscopy , Humans , Male , Middle Aged , Postoperative Complications , Retrospective Studies , Skin
15.
J Biochem ; 116(5): 986-90, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7896760

ABSTRACT

The Escherichia coli phenylalanine-sensitive DAHP (3-deoxy-D-arabino-heptulosonate 7-phosphate) synthetase (aroG product) is one of the DAHP synthetase isozymes that catalyze the first committed step in the biosynthesis of aromatic amino acids and vitamins. Through target-directed mutagenesis of the cloned aroG on a plasmid vector, followed by screening of phenylalanine-resistant colonies, we isolated a clone (pG908) showing feedback-insensitive mutation of DAHP synthetase. The mutations were identified as a T-->A mutation at nucleotide 22, and a C-->T mutation at nucleotide 539, causing a Leu-8 to Ile-8 mutation and a Ser-180 to Phe-180 substitution, respectively. The resulting enzyme exhibited comparable enzymatic activity to the wild type, but the degree of feedback inhibition had declined from approximately 60% to less than 10% in the presence of 20 mM phenylalanine in the assay medium. Replacement of Ile-8 by Leu, and substitution of Phe-180 with Ser, Asn and Cys, using site-directed mutagenesis, demonstrated that Ser-180 is a critical residue in the feedback inhibition of AroG. The result suggests that the major role played by Ser-180 may not involve a simple charge-size effect in the Phe-binding site of the enzyme molecule, but rather may involve more complicated molecular interactions occurring in the feedback inhibition mechanisms.


Subject(s)
3-Deoxy-7-Phosphoheptulonate Synthase/antagonists & inhibitors , 3-Deoxy-7-Phosphoheptulonate Synthase/chemistry , 3-Deoxy-7-Phosphoheptulonate Synthase/metabolism , Escherichia coli/enzymology , Serine/chemistry , Base Sequence , Enzyme Inhibitors/chemistry , Molecular Sequence Data , Mutagenesis, Site-Directed , Phenylalanine/pharmacology
16.
Cell Immunol ; 157(1): 249-62, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7518752

ABSTRACT

An immune response directed against type II collagen (CII) has been reported in several autoimmune diseases including the animal models of collagen-induced arthritis (CIA) and collagen-induced autoimmune ear disease (CIAED). In this communication, we have found that T cells from type II collagen-immunized DBA/1-lac could transfer auricular chondritis to naive mice. The T cells from type II collagen-immunized H-2r and H-2q mice recognize different epitopes from the CB11 peptide of CII. The CII-specific T cells from H-2q background mice recognize peptide residues p121-147 (P1) but do not respond to residues p211-247 (P2). The T cells of H-2r mice immunized with CII respond better to P2 rather than P1. By altering certain amino acids within these epitopes, the response of CII-specific TCR to antigen has been increased or abolished. Our results suggest that the lysine residues at positions 129, 141, and 147 in P1, the arginine residue at position 227, and glutamic acid at position 230 in P2 might play an important role in the trimolecular interaction. Ten clonally distinct T cell hybridomas specific for CII have been established from H-2r B10.RIII mice and the beta chains of their TCR have been analyzed. Three subfamilies, V beta 1, V beta 6, and V beta 8, were utilized with dominant expression of V beta 8 (60%). This is quite similar to the pattern found in type II collagen-induced arthritis in H-2q mice. This preferential use of V beta 8 in CIAED implies that an immunotherapy may make it possible to control this autoimmune disease, even in a MHC-diverse situation.


Subject(s)
Autoimmune Diseases/immunology , Collagen/immunology , Ear Diseases/immunology , Epitopes/immunology , Receptors, Antigen, T-Cell, alpha-beta/genetics , Amino Acid Sequence , Animals , Autoimmune Diseases/genetics , Base Sequence , Cartilage Diseases/immunology , Cartilage Diseases/pathology , Ear Diseases/pathology , Hybridomas , Lymphocyte Activation , Mice , Mice, Inbred DBA , Mice, Inbred Strains , Molecular Sequence Data , T-Lymphocytes/physiology , T-Lymphocytes/transplantation
17.
Eur J Radiol ; 18(1): 1-5, 1994 Feb.
Article in English | MEDLINE | ID: mdl-8168572

ABSTRACT

An intravascular foreign body is an iatrogenic complication that occurs during arterial or venous catheterization or interventional procedures. The foreign body could either be a catheter fragment, a dislodged coil, or a steel guide wire. From January 1987 to December 1992, 12 cases of intravascular foreign-body removals were performed by a percutaneous method at Mackay Memorial Hospital. Of the 12 cases, five were dislodged steel guide wires, four were broken CVP catheters, two were dislodged coils, and one was Port-A fragment. The techniques we used were the loop-snare technique (two cases) and stone basket retriever (10 cases). Eleven cases of intravascular foreign bodies were removed by non-surgical percutaneous retrieval but one case was a failure due to improper extraction of a dislodged steel guide wire. The patient received surgical extraction by regional venotomy finally. No major complications were noted during or after these procedures.


Subject(s)
Blood Vessels , Foreign Bodies/therapy , Adolescent , Adult , Aged , Aged, 80 and over , Angiography , Catheterization/adverse effects , Child , Child, Preschool , Embolization, Therapeutic/adverse effects , Equipment Failure , Female , Foreign Bodies/diagnostic imaging , Foreign Bodies/etiology , Humans , Male , Middle Aged
18.
World J Surg ; 16(6): 1188-91; discussion 1192, 1992.
Article in English | MEDLINE | ID: mdl-1333684

ABSTRACT

Management of recurrent hepatocellular carcinoma in a cirrhotic liver remnant is a difficult but challenging problem. To investigate the difference in survival between treatment by repeat resection and treatment by transcatheter arterial chemoembolization (TAE), a retrospective controlled study was conducted. Four patients with nodular recurrence received limited second operations which included right hepatic segmentectomy (2 patients), left lateral segmentectomy (1 patient), and subsegmental wedge resection (1 patient). Eight matched patients received a total of 16 repeated sessions of chemoembolizations. Complications of the TAE group consisted of gastrointestinal bleeding (2 patients), acute pancreatitis (1 patient), and acute cholecystitis (1 patient). No complication developed in the resection group. The 4 patients undergoing a second operation have survived 21, 26, 34, and 54 months after repeat surgery. Seven (87.5%) of the 8 patients receiving TAE died 4 to 11 months after TAE. The resection group survived significantly longer than the TAE group (p < 0.01). Our results suggest that it is more advisable to perform a second operation than to undertake chemoembolizations for patients with cirrhosis and nodular recurrent hepatocellular carcinoma with acceptable functional liver reserve.


Subject(s)
Carcinoma, Hepatocellular/therapy , Chemoembolization, Therapeutic , Liver Cirrhosis/complications , Liver Neoplasms/therapy , Neoplasm Recurrence, Local/therapy , Adult , Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/surgery , Female , Humans , Liver Neoplasms/complications , Liver Neoplasms/surgery , Male , Middle Aged , Neoplasm Recurrence, Local/surgery , Reoperation , Retrospective Studies
19.
Br J Surg ; 79(7): 663-6, 1992 Jul.
Article in English | MEDLINE | ID: mdl-1643480

ABSTRACT

Biliary stricture represents a challenging problem in the treatment of hepatolithiasis because of its association with treatment failure and stone recurrence. The long-segment type of stricture is difficult to manage and is likely to recur. To investigate the necessity for biliary stenting after balloon dilatation therapy, 20 consecutive patients with long-segment strictures who had 22 stents (group 1) were compared with ten patients who refused stenting (group 2). The long-segment strictures in group 1 were located on the right side in 80 per cent of patients, on the left side in 10 per cent, and were bilateral in 10 per cent. The stents, varying from 8 to 12 Fr, were retained for at least 6 months. They were inserted through the routes of a matured T tube track (five cases), percutaneous transhepatic track (14 cases), a jejunal limb (two cases) and a fistula (one case). Complications of stenting consisted of dislodgement (one case), haemobilia (two cases), cholangitis (two cases) and intrahepatic abscess (one case). The cumulative probability of stricture recurrence in group 1 was 10 per cent, 15 per cent and 21 per cent at 2, 3 and 4 years, respectively, whereas in group 2 it was 80 per cent at 2 years (P less than 0.003). The results suggest that intrahepatic biliary stenting after balloon dilatation appears necessary and helpful in the management of hepatolithiasis with long-segment biliary strictures.


Subject(s)
Bile Ducts, Intrahepatic/diagnostic imaging , Calculi/surgery , Liver Diseases/surgery , Stents , Adult , Bile Duct Diseases/diagnostic imaging , Bile Duct Diseases/therapy , Catheterization , Constriction, Pathologic/therapy , Female , Humans , Male , Middle Aged , Postoperative Complications/etiology , Radiography , Time Factors
20.
Zhonghua Yi Xue Za Zhi (Taipei) ; 48(2): 116-20, 1991 Aug.
Article in English | MEDLINE | ID: mdl-1654181

ABSTRACT

The use of computed tomography (CT) has had a tremendous impact on the evaluation and management of blunt abdominal trauma. The ability of CT to confirm the absence of intraperitoneal injury and/or significant hemoperitoneum, in correlation to the patient's physiological status, provides extremely valuable information so that unnecessary abdominal surgery is avoided. CT not only demonstrates the presence of injury and delineates it's extent, including the size of the hemoperitoneum, but may also provide information concerning the hemodynamic status of the patient. We reviewed the abdominal CT examination of 38 patients with blunt abdominal trauma at our institution from April 1989 to May 1990. There were no false negative cases and only one false positive case. Thus, we concluded that CT is not only a highly sensitive and accurate modality, but also an invaluable radiological diagnostic tool in the evaluation of blunt abdominal injury.


Subject(s)
Abdominal Injuries/diagnostic imaging , Tomography, X-Ray Computed , Wounds, Nonpenetrating/diagnostic imaging , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Male , Middle Aged
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