Diffusion-Weighted Magnetic Resonance Imaging in Liver Graft Rejection.

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.

Magnetic Resonance Spectroscopy in Living-Donor Liver Transplantation.

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.

Pharmacokinetic Analysis of Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Distinguishing Hepatocellular Carcinoma From Cholangiocarcinoma in Pre-Liver Transplantation Evaluation.

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.

TCRV and TCRJ gene usage in MBP responding T cells from (B10.PL x PL/J)F1 mice is biased towards that of B10.PL mice.

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.

A single Ser-180 mutation desensitizes feedback inhibition of the phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthetase in Escherichia coli.

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.

Structure-function studies of Escherichia coli biotin synthase via a chemical modification and site-directed mutagenesis approach.

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.

Delayed formation of gallstone after transcatheter arterial embolization for hepatocellular carcinoma. Is elective cholecystectomy advisable during hepatectomy?

Two hundred twenty-five transcatheter hepatic arterial embolizations (TAEs) were performed on 137 patients with hepatocellular carcinoma (HCC) during a three-year period. The postembolization changes of the gallbladder were studied by regular follow-up with ultrasonography. Twenty-four patients (10.7%) were found to have an acute infarction of the gallbladder within two weeks immediately following chemoembolization. Gallbladder infarction was related to inadequate superselectivity, regurgitation of chemoembolus, or unavoidable anatomic limitations. Four of the 24 patients were found to have delayed formation of gallstones, with the time lapses after TAEs being 2, 2, 3, and 5 months, respectively. One patient underwent surgical reexploration for cholecystectomy 14 months after resection of her HCC because of intractable symptoms and signs of chronic cholecystitis. There are four possible mechanisms of development of gallstones. Cholecystectomy should be performed during the elective hepatectomy for resectable HCC in patients who have received preoperative TAEs.

Secondary biliary cirrhosis. A limiting factor in the treatment of hepatolithiasis.

To investigate whether the coexistence of secondary biliary cirrhosis plays a limiting role in the treatment of hepatolithiasis, we retrospectively compared the clinical course and results of stone treatment in 30 patients with secondary biliary cirrhosis (8 in Child's class A and 22 in Child's class B) (group 1) and 240 patients with noncirrhotic biliary calculi (group 2). The hospital mortality, morbidity of treatment, mortality of treatment, and the percentage of treatment failure in group 1 were 20%, 40%, 6.7%, and 16.7%, respectively. Those in group 2 were 8%, 10%, 3.8%, and 10%, respectively. The modes of treatment for stone removal included surgery with postoperative cholangioscopy and percutaneous transhepatic cholangioscopy. There was a statistically significant difference between these two groups in the hospital mortality and the morbidity of treatment. We conclude that hepatolithiasis and biliary stricture should be treated early, before the development of secondary biliary cirrhosis. However, even after cirrhosis occurs, aggressive treatment does not increase the mortality of treatment or the treatment failure rate.

Non-surgical retrieval of intravascular foreign body: experience of 12 cases.

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.

Course and management of renal subcapsular abscess in a 63-year-old diabetic woman.

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.

Magnetic resonance fat quantification in living donor liver transplantation.

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.

Magnetic resonance cholangiography in living donor liver transplantation: comparison of preenhanced and post-gadolinium-enhanced methods.

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".

Burden of tuberculosis among aboriginal and non-aboriginal Taiwanese, 1996-2006.

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.

The value and role of computed tomography in blunt injury of the abdomen.

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.

Percutaneous biliary stone removal under fluoroscopy.

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.

Abdominal fluid collection secondary to acute pancreatitis: treated with percutaneous catheter drainage.

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.

Effects of quinidine and cimetidine on the methamphetamine level in the rat brain.

The drug interaction between methamphetamine and quinidine/cimetidine was investigated in terms of distribution of methamphetamine to the brain. The concentrations of methamphetamine and amphetamine in the brain after an s.c. injection of methamphetamine were determined in rats pretreated with a single oral dose of quinidine or cimetidine. Both drugs markedly enhanced the increase in the concentrations of methamphetamine and its metabolite, amphetamine. These results suggest that the recent finding of the enhancements of the behavioral effect of methamphetamine by quinidine and cimetidine is due to the increase in levels of methamphetamine and amphetamine in the brain by these pretreatment drugs.

Limitations of percutaneous transhepatic cholangioscopy in the removal of complicated biliary calculi.

To investigate the limitations of percutaneous transhepatic cholangioscopic lithotomy (PTCSL) in the management of retained or reformed biliary calculi, we conducted a retrospective study of 50 patients who had received PTCSL for complicated biliary calculi during a period of 32 months. The calculi were located in the common bile duct (24%), the intrahepatic bile ducts (60%), and in both the common bile duct and intrahepatic bile ducts (16%). The adjunctive techniques in PTCSL included balloon dilatation for the biliary stricture, electrohydraulic lithotripsy (EHL) for crushing large impacted stones, and flushing techniques, biliary spoons, and basket catheters for stone fragmentation and grasping. The overall percutaneous manipulations totaled 221 procedures, including 124 sessions of PTCS. In each patient, the number of sessions of PTCS varied from 1 to 7. In our series, the main complications of PTCS therapy, rarely reported in the literature, included pain intolerance in 7 cases (14%), minor bleeding in 7 cases (14%), and massive bleeding which needed angiographic diagnosis and therapy for hemostasis in 5 cases (10%). Secondary biliary cirrhosis, severe biliary stricture and angulations, previous shunt surgery, neovascularization surrounding the chronic inflammatory stenotic intrahepatic bile ducts, pseudoaneurysm formation, and coexistent cholangiocarcinoma contributed to the vulnerability of bleeding during manipulations. The complications resulted in treatment failure in 11 patients (22%). We conclude that PTCS is a useful alternative treatment to surgery for biliary calculi, but it has limitations that obviate complete stone clearance.