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H J Chiang

Publications and source records attributed to H J Chiang.

25 records · Page 2Linked to original sources
PubMed1984

Preparation and characterization of pentaammineruthenium-(histidine-83)azurin: thermodynamics of intramolecular electron transfer from ruthenium to copper.

The reaction between a5RuH2O2+ (a is NH3) and Pseudomonas aeruginosa azurin at pH 7, followed by oxidation, yields a5Ru(His-83)3+-azurin(Cu2+) as the major product. Spectroscopic measurements (UV-visible, CD, EPR, and resonance Raman) indicate that the native structure is maintained in the modified protein. The site of ruthenium binding (His-83) was identified by peptide mapping. The a5RuHis/Cu ratio in the modified protein, determined from the EPR spectrum, is 1:1, and the reduction potentials (vs. normal hydrogen electrode, pH 7.0, 25 degrees C) are blue copper (Cu2+/1+), 320 +/- 2 mV; a5Ru(His-83)3+/2+, 50 +/- 10 mV. From measurements of the reduction potentials at several temperatures in the 5-40 degrees C range, delta H degree for intramolecular Ru2+ ----Cu2+ electron transfer was estimated to be -12.4 kcal mol-1 (1 cal = 4.184 J). Analysis of kinetic data in light of the electron transfer exothermicity indicates that the reorganizational enthalpy of the blue copper site can be no larger than 7.1 kcal mol-1.

Azurin↗
PubMedDate not supplied

Dilatation of intrahepatic biliary strictures in patients with hepatolithiasis.

To investigate the role of balloon dilatation in the management of complicated hepatolithiasis with intrahepatic biliary stricture, 57 consecutive patients who received 208 sessions of dilatation in addition to the usual treatment were analyzed. The strictures were located in the right intrahepatic ducts (84.2%), left intrahepatic ducts (12.3%), or both (3.5%). Dilatation began 3-4 weeks after surgery. The routes of dilatation included the matured T-tube tract (3 cases), percutaneous transhepatic biliary drainage tracts (42 cases), and both (12 cases). The immediate overall success rate of complete stone clearance increased significantly from 0% predilatation to 94.7% postdilatation. The main complications of dilatation therapy consisted of septicemia (10.5%), hemobilia (10.5%), and mild diarrhea (80%). Eight patients (14%) with long-segment strictures received 11 postdilatation biliary stentings. Complications were 1 patient with occlusion and 2 patients with "spontaneous" hemobilia. Severe multiple strictures and coexistent secondary biliary cirrhosis were the contributing factors to complications. During the follow-up of 3.4 +/- 1.2 years, recurrence of strictures was found in 4 patients. Two of them belonged to the stenting group. The cumulative probability of restricture was low: 4% at 2 years, 6% at 2.5 years, and 8% at 3 years. We conclude that in complicated cases of hepatolithiasis with intrahepatic biliary stricture, dilatation and stenting are good adjuvant therapies.

Adult↗
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

Repeat operation for nodular recurrent hepatocellular carcinoma within the cirrhotic liver remnant: a comparison with transcatheter arterial chemoembolization.

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.

Adult↗
PubMedDate not supplied

Differential diagnosis between intussusception and gastroenteritis by plain film.

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.

Adolescent↗