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Biomedical subjects

C S Wang

Publications and source records attributed to C S Wang.

At least 91 records · Page 5Linked to original sources
PubMed1995

Congestive gastropathy in cirrhotic patients: correlation between endoscopic and histological findings.

Congestive gastropathy is a common cause of gastrointestinal bleeding in cirrhotic patients. Forty-six patients with cirrhosis of the liver and 225 control subjects matched in age and sex without cirrhosis of the liver entered the study. We studied the prevalence of congestive gastropathy in cirrhotic patients, and the relationship between endoscopic and histological findings. Congestive gastropathy seen endoscopically was found to be more common in the cirrhotic group than in the control (85% vs. 5%, P < 0.05). The sensitivity, specificity and positive predictive value were 85%, 95% and 76%, respectively. The presence of endoscopic congestive gastropathy was correlated with the severity of liver disease (P < 0.05), but not to the etiology of cirrhosis and the size of esophageal varices with or without red color sign. Endoscopic congestive gastropathy showed no correlation with the histological features including gastritis, interstitial edema, vessel ectasia/congestion and hemosiderin in endoscopic biopsy specimens. In conclusion, congestive gastropathy is a common finding in cirrhotic patients. Its appearance is closely correlated with the severity of liver disease. There is no good correlation between endoscopic congestive gastropathy and mucosal histology.

Adult↗
PubMed1995

Duodenal variceal bleeding--successfully treated by mesocaval shunt after failure of sclerotherapy.

A 68-year-old male patient with liver cirrhosis and bilateral diffuse hepatoma presented with massive upper gastrointestinal bleeding caused by rupture of duodenal varices. Surgery had to be performed after sclerotherapy failed to stop the bleeding. A mesocaval shunt with graft interposition controlled the hemorrhage. Follow-up endoscopic examination showed complete disappearance of the varices. After surgery, the patient had two episodes of mild hepatic encephalopathy, which easily responded to treatment. There was no rebleeding, and he died of hepatic malignancy ten months after the shunt procedure.

Aged↗
PubMed1994

Proline-rich domain and glycosylation are not essential for the enzymic activity of bile salt-activated lipase. Kinetic studies of T-BAL, a truncated form of the enzyme, expressed in Escherichia coli.

We have expressed and purified a truncated recombinant human milk bile salt-activated lipase (T-BAL) from the T7 expression system in Escherichia coli. This T-BAL contains the N-terminal 538 residues of the 722-residue native enzyme. The purified T-BAL, when assayed with PANA (p-nitrophenyl acetate), had a specific activity of 64 +/- 2 units/mg (n = 4), as compared to 52 units/mg for the native enzyme. Because the recombinant T-BAL expressed in E. coli is not glycosylated, these results indicated that the highly glycosylated C-terminal region of BAL is not essential for catalytic function. Heat inactivation patterns of native BAL and T-BAL were found to be similar, further suggesting that the folding of T-BAL is similar to that of the catalytic domain of the native enzyme. With the availability of a sufficient amount of recombinant T-BAL, the specificity and kinetics of T-BAL and native BAL were compared. Fluorescence studies of T-BAL indicated that it has a slightly higher affinity for the monomeric form of taurocholate with a dissociation constant (KA) of 0.32 mM, compared with the reported 0.37 mM for the native enzyme. Further kinetic analysis indicated that there are enzyme specificity changes revealed with the use of PANA and PANB (p-nitrophenyl butyrate) as substrates. When assayed in the presence of taurocholate, T-BAL has a higher turnover rate constant with p-nitrophenyl acetate than with p-nitrophenyl butyrate, which was found to be in contrast to native BAL.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Probing of active site structure of lipoprotein lipase: contribution of activation entropy in the catalysis.

In this study, I have utilized the chromogenic short-chain esters of p-nitrophenol as substrates for probing the active site structure of lipoprotein lipase (LPL). The results indicated that there is a consistent trend in the decrease of the Michaelis-Menten constant with increase of the acyl-chain length. Therefore, it was concluded that the decrease of reactivity with increased chain length is probably not a consequence of a lower affinity of the substrate for the enzyme. The fact that butyrate ester has the optimum acyl-chain length to be a substrate of LPL can be attributed to its chain length being long enough for optimum interaction with the active site His-Ser-Asp triad in forming the transition state complex; yet it is short enough to provide freedom for optimum positioning of the ester bond for transition state complex formation. It is likely that, because of the structural features of the enzyme active site, the increase of the acyl-chain of the substrate from C4 to C5 initiates the contact between the hydrocarbon tail of the acyl-chain and the hydrophobic surface of the active site pocket. Such an interaction, although it causes the stabilization of the ground state enzyme-substrate complex, also causes a large increase in negative activation entropy because of the restricted random motion of the bound substrate. The latter effect is also the likely cause for the progressively lower reactivity of the enzyme with the increase of acyl-chain length above C4, as seen in the LPL-catalyzed lipolysis of monoacid triacylglycerols.

Amino Acid Sequence↗
PubMed1994

Obstructive jaundice secondary to ruptured hepatocellular carcinoma into the common bile duct. Surgical experiences of 20 cases.

BACKGROUND: Hepatocellular carcinoma (HCC) presenting as obstructive jaundice caused by floating tumor debris in common bile duct is rare. Taiwan has a high incidence of HCC and cirrhosis. The authors report their clinical experiences and evaluate the results of different treatment modalities for this disease. METHODS: A retrospective study was undertaken to review 20 patients with obstructive jaundice secondary to ruptured HCC into common bile duct during the 12 years period. RESULTS: All patients on initial examination had recurrent episodic jaundice or cholangitis. Jaundice was relieved by nonsurgical, percutaneous transhepatic biliary stenting in 4 patients and surgical intubation with T-tube drainage in 16. Types of treatment for those who were treated nonsurgically were percutaneous transhepatic biliary stenting in two patients, followed by transcatheter hepatic arterial embolization in another two patients. For the 16 patients who were treated surgically, the types of treatment were T-tube or Y-tube drainage in 11, T-tube drainage followed by hepatic resection in 2, T-tube drainage and hepatic arterial ligation in 1, and T-tube drainage followed by transcatheter hepatic arterial embolization in the other 2. Liver cirrhosis was the associated disease in 12 (75%). Four patients (20%) died in the hospital. The mean survival time for 12 patients with only surgical or nonsurgical biliary stenting was 3.9 months. For the three patients with percutaneous hepatic arterial embolization, the mean survival time was 8.0 months. Two patients who had undergone hepatic resection had a better postoperative survival time, with one surviving for more than 5 years. CONCLUSION: Clinical features, types of management, operative findings, and survival in 20 patients with HCC obstructing the common bile duct by tumor thrombi were reviewed. Not all patients with this disease were terminally ill. With proper management, good palliation and occasional cure are possible.

Adult↗
PubMed1994

Postoperative recurrence of hepatocellular carcinoma. Two hundred five consecutive patients who underwent hepatic resection in 15 years.

OBJECTIVES: To report the results of our investigation of the postoperative intrahepatic recurrent rates and the patterns of recurrence and to determine the factors that influenced these patterns of recurrence. DESIGN: Case series. SETTING: Department of Surgery, Chang Gung Memorial Hospital, Taipei, Taiwan. PATIENTS: Between 1977 and 1991, 162 men and 43 women with hepatocellular carcinoma underwent hepatic resection. RESULTS: The surgical mortality rate was 4.4%. Of the 196 patients who were discharged from the hospital, 114 have since died and 20 were not available for follow-up. The overall cumulative recurrent rates for the last 5 years (1987 through 1991) were 59.7%, 65.0%, 76.5%, 77.0%, and 79.7%, respectively. Eighty patients experienced intrahepatic recurrence. Of these, 21 (26.2%) had recurrence near the resected stump, 43 (53.8%) had a single nodular recurrence in the remnant liver, and 16 (20%) had wide-spread multinodular recurrence. The patients with resected margins of less than 1 cm in diameter had relatively higher recurrence rates than those with resected margins of greater than 1 cm in diameter. All recurrences were noted within 3 years of the resection. The preoperative serum alpha-fetoprotein levels were directly related to the length of time to recurrence (ie, the higher the serum alpha-fetoprotein level, the sooner the recurrence). CONCLUSIONS: The postoperative intrahepatic remnant rate is very high; 80% by 5 years after resection. The preoperative serum alpha-fetoprotein level and adequacy of the cut margin significantly influenced the recurrence rate.

Carcinoma, Hepatocellular↗
PubMed1994

Upper gastrointestinal tract ablation for patients with extensive injury after ingestion of strong acid.

OBJECTIVE: Extensive corrosive injury involving the structures beyond the pylorus caused by ingestion of strong acid has a poor prognosis. We reviewed six cases of patients who underwent total upper gastrointestinal tract ablation to see the effect of this extensive procedure for such an injury. DESIGN: Case series. SETTING: Tertiary care center. PATIENTS: Six patients who ingested more than 250 mL of 20N hydrochloric acid were treated in the Department of Surgery, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China, from 1986 to 1992. RESULTS: Three patients with preoperative metabolic acidosis and renal failure died of multiple organ failure within the first postoperative month. The other three patients survived the acute stage. While being readied for a late reconstructive procedure, sepsis developed in one patient due to cholecystostomy leakage about 1 year postoperatively. Another patient died of respiratory failure after development of aspiration pneumonia due to poor drainage of a spit fistula, after surviving for 6 months. Only one patient had a good recovery following a full reconstruction procedure and restoration of the continuity of the gastrointestinal tract. CONCLUSIONS: Three of six patients died in the hospital. The risk factors were preoperative metabolic acidosis, renal failure, and an upper jejunal resection greater than 100 cm in length. Early and aggressive approaches to resect all the necrotic tissue certainly provide good chances to survive the acute stage and later reconstruction.

Adult↗
PubMed1994

Regulation of bone marrow stromal cell differentiation by cytokines whose receptors share the gp130 protein.

The bone marrow stroma consists of a heterogeneous population of cells which participate in osteogenic, adipogenic, and hematopoietic events. The murine stromal cell line, BMS2, exhibits the adipocytic and osteoblastic phenotypes in vitro. BMS2 differentiation was examined in response to cytokines which share the gp130 signal transducing protein within their receptor complex. Four of the cytokines (interleukin 6, interleukin 11, leukemia inhibitory factor, and oncostatin M) inhibited hydrocortisone-induced adipocyte differentiation in a dose dependent manner based on lipid accumulation and lipoprotein lipase enzyme activity. Inhibition occurred only when the cytokines were present during the initial 24 h of the induction period; after 48 h their effects were diminished. Likewise, these cytokines increased alkaline phosphatase enzyme activity twofold in preadipocyte BMS2 cells. Both leukemia inhibitory factor and oncostatin M induced early active gene expression in resting preadipocyte BMS2 cells and decreased the steady state mRNA level of a unique osteoblastic gene marker, osteocalcin. A fifth cytokine whose receptor complex shares the gp130 protein, ciliary neurotrophic factor, did not significantly regulate stromal cell differentiation when added by itself. However, with the addition of a missing component of its receptor complex, ciliary neurotrophic factor receptor alpha protein, this cytokine also inhibited BMS2 adipogenesis. Together, these data indicate that the cytokines whose receptors share the gp130 protein can modulate stromal cell commitment to the adipocyte and osteoblast differentiation pathways.

Adipocytes↗
PubMed1994

Triglyceride-rich lipoprotein interactions with Lp(a).

We found a significantly reduced incidence of increased lipoprotein(a) (Lp(a)) levels in subjects with triglycerides (TG) greater than 150 mg/dl compared with those with TG levels lower than 150 mg/dl. This was the case in patients with angiographically documented coronary artery disease (CAD) and in subjects with no CAD. We explored the potential role of lipoprotein lipase (LPL) in mediating this relationship. Lp(a) and LDL2 exhibited a minimal effect on the rate constant for degradation of VLDL-TG by LPL (13% inhibition). Binding analyses indicated no differences between VLDL and LDL with respect to Lp(a) binding, and lipolysis only reduced binding by 30% at 75% degradation of VLDL-TG. Our study indicates that the inverse relationship between elevated plasma TG and Lp(a) levels is not caused by activation of LPL by Lp(a) either due to failure of Lp(a) to bind to VLDL or its lipolytic remnants. It is hypothesized that this relationship could stem from the enhanced clearance of TG-rich lipoproteins in individuals with higher levels of Lp(a) by receptor-mediated events.

Adult↗
PubMed1994

Alternative routes of enzymic cyanide metabolism in Pseudomonas fluorescens NCIMB 11764.

Cell-free extracts from Pseudomonas fluorescens NCIMB 11764 catalysed the degradation of cyanide into products that included CO2, formic acid, formamide and ammonia. Cyanide-degrading activity (CDA) was localized to cytosolic cell fractions and was observed at substrate concentrations as high as 100 mM (2600 mg CN-I-1). At least two different CDAs could be distinguished by: (i) the determination of reaction product stoichiometries, (ii) requirements for NADH and oxygen, and (iii) kinetic analysis. The first activity produced CO2 and NH3 as reaction products, was dependent on oxygen and NADH for activity, and displayed an apparent Km for cyanide of 1.2 mM. The second activity generated formic acid (and NH3) plus formamide as reaction products, was oxygen independent, and had an apparent Km of 12 mM for cyanide. The first enzymic activity was identified as cyanide oxygenase as previously described [Harris, R. E. & Knowles, C. J. (1983) FEMS Microbiol Lett 20, 337-341] whereas the second activity is believed to consist of two enzymes, a cyanide nitrilase (dihydratase) and hydratase (EC 4.2.1.66). In addition to these enzymes, cyanide-grown cells were also induced for formate dehydrogenase (EC 1.2.1.2) thereby providing a means of recycling NADH utilized by cyanide oxygenase. A mutant strain having lost the ability to grow on cyanide as a nitrogen source was isolated and shown to be defective in cyanide oxygenase, but not the cyanide nitrilase/hydratase enzymes. This finding together with results showing that the substrate affinity of cyanide oxygenase was tenfold greater than for the nitrilase/hydratase enzymes, indicates that it is this enzyme that is most important in cyanide assimilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia↗
PubMed1994

Two classes of proteins and mRNAs in Lilium longiflorum L. indentified by human vitronectin probes.

Vitronectin (VN) is a substrate adhesion molecule, an extracellular matrix glycoprotein that facilitates cell adhesion and cell movement in animals. We have reported the cross-reactivity of a 55-kD protein in plants with rabbit anti-human VN antibodies and the presence of VN-like sequences in plant genomes using a human VN cDNA probe. We have extended these studies by using human VN riboprobes to detect VN-like mRNAs in lily (Lilium longiflorum L.) and soybean. In both species, two mRNAs were detected. We have also identified a new cross-reactive protein (41 kD) using a different preparation of human VN antiserum. In lily roots five 41-kD isoforms were observed, whereas only three of these isoforms accumulated in leaves. Monospecific antibodies prepared against the plant proteins cross-reacted with the human VN protein and vice versa. We have purified the 41-kD protein using two-dimensional gel electrophoresis, and amino acid composition analysis indicates that it is similar in composition to human VN.

Amino Acids↗
PubMed1994

Chalcone synthase mRNA and activity are reduced in yellow soybean seed coats with dominant I alleles.

The seed of all wild Glycine accessions have black or brown pigments because of the homozygous recessive i allele in combination with alleles at the R and T loci. In contrast, nearly all commercial soybean (Glycine max) varieties are yellow due to the presence of a dominant allele of the I locus (either I or i) that inhibits pigmentation in the seed coats. Spontaneous mutations to the recessive i allele occur in these varieties and result in pigmented seed coats. We have isolated a clone for a soybean dihydroflavonol reductase (DFR) gene using polymerase chain reaction. We examined expression of DFR and two other genes of the flavonoid pathway during soybean seed coat development in a series of near-isogenic isolines that vary in pigmentation as specified by combinations of alleles of the I, R, and T loci. The expression of phenylalanine ammonia-lyase and DFR mRNAs was similar in all of the gene combinations at each stage of seed coat development. In contrast, chalcone synthase (CHS) mRNA was barely detectable at all stages of development in seed coats that carry the dominant I allele that results in yellow seed coats. CHS activity in yellow seed coats (I) was also 7- to 10-fold less than in the pigmented seed coats that have the homozygous recessive i allele. It appears that the dominant I allele results in reduction of CHS mRNA, leading to reduction of CHS activity as the basis for inhibition of anthocyanin and proanthocyanin synthesis in soybean seed coats. A further connection between CHS and the I locus is indicated by the occurrence of multiple restriction site polymorphisms in genomic DNA blots of the CHS gene family in near-isogenic lines containing alleles of the I locus.

Acyltransferases↗
PubMed1994

Carbon dioxide-enhanced ultrasonography of liver tumors.

CO2 gas-enhanced ultrasonography was performed in 37 patients (47 studies) for the purpose of detecting small tumors and evaluating differential diagnosis. With conventional ultrasonography, 62 lesions were identified in 25 patients with HCC, 13 tumors were identified in eight patients with hemangioma, and multiple tumors were found in four patients with metastatic adenocarcinoma. CO2-enhanced ultrasonography detected five additional hemangiomas, 12 additional nodules in HCC, and the same number of metastatic nodules. The patterns of CO2 enhancement were characterized as homogeneous, heterogeneous, rim, internal spotted, negative, and mixed (more than one pattern in one lesion). The rim enhancement pattern was found to be specific for hemangioma. The internal spotted enhancement pattern was found exclusively in HCC. All the lesions that demonstrated negative enhancement were treated HCC. All the metastatic tumors demonstrated the mixed rim and internal spotted enhancement pattern. We suggest that CO2-enhanced ultrasonography is a useful tool in detecting small liver tumors. It can also help in the differentiation among various hepatic tumors.

Adenocarcinoma↗
PubMed1994

Rupture of the diaphragm after blunt trauma.

OBJECTIVE: To analyse our cases of acute rupture of the diaphragm after blunt trauma to find out how to diagnose it earlier and manage it more promptly in future. DESIGN: Retrospective study of casenotes. SETTING: Division of general surgery, district hospital, Taiwan. PATIENTS: 50 Patients who presented with acute rupture of the diaphragm after blunt trauma during the 10 year period 1982-91. MAIN OUTCOME MEASURES: Morbidity and mortality. RESULTS: The left hemidiaphragm was injured in 43 cases (86%), and the right in 7 (14%). The most common cause was road traffic accidents. 48 Patients had associated injuries, mainly to the chest and abdomen, and pelvic fractures. 44 Ruptured diaphragms were diagnosed before operation by chest radiography or upper gastrointestinal contrast examination. The transabdominal approach was the most appropriate, because 23 patients had intra-abdominal visceral injuries as well. 20 Patients (40%) had complications, and the rate was 33% among those treated within 24 hours and 70% among those whose treatment was delayed longer than 24 hours (p = 0.067). There were 3 deaths (6%); one patient died of empyema of the right chest as a result of simultaneous perforation of a hollow viscus. 6 Patients were permanently disabled by head and spinal injuries, and pelvic fractures. CONCLUSION: The prognosis of repairing diaphragmatic hernias is good as the disability rate is low. The diagnosis should be kept in mind in all patients with chest injuries, pelvic fractures, or abdominal injuries with hypoxaemia, as this will result in earlier treatment and improve prognosis. The transabdominal approach is the most appropriate because it makes simultaneous abdominal injuries easier to treat. Correct operative management at an early stage will keep mortality to a minimum.

Adolescent↗
PubMed1993

A reappraisal of cholangiocarcinoma in patient with hepatolithiasis.

BACKGROUND: Hepatolithiasis associated with cholangiocarcinoma is not often encountered. During the past 3 years, an increased incidence of patients with hepatolithiasis associated with cholangiocarcinoma was noted. Data were needed to reliably determine the incidence of this disease. METHODS: Data concerning the relationship between cholangiocarcinoma and hepatolithiasis are presented. The treatment modalities and factors that influence long-term survival are discussed. RESULTS: The overall incidence of cholangiocarcinoma in association with hepatolithiasis was 5.0% (55 in 1105). Before 1987, 65% of cholangiocarcinoma in association with hepatolithiasis was diagnosed postoperatively. After 1987, the incidence of accurate preoperative diagnosis increased (22.8%), and in most of the other instances (62.8%), the diagnosis was made at laparotomy. Surgical procedures consisted of common bile duct exploration with T-tube drainage (100%) and hepatectomy (38.2%). Mortality for patients who underwent surgery was 5.4%; they died of recurrent cholangitis. The overall median survival time of patients with cholangiocarcinoma in association with hepatolithiasis was 10.4 months; the 1-, 2-, and 4-year cumulative survival rates were 30.0%, 12.7%, and 3.6%, respectively. Patients with hepatectomy or the presence of mucobilia had better survival rates (P < 0.05). CONCLUSIONS: The overall incidence of hepatolithiasis associated with cholangiocarcinoma was 5%. In most patients with cholangiocarcinoma in association with hepatolithiasis, diagnosis can be made preoperatively and at laparotomy. Patients with hepatectomy or presence of mucobilia had better survival rates.

Adenoma, Bile Duct↗
PubMed1993

Liver transplantation for a hepatitis B-related cirrhotic patient.

A patient with chronic end-stage liver cirrhosis resulting from a hepatitis B viral infection had a successful liver transplantation performed on 1 July 1991. Preoperative serology revealed that both HBsAg and HBeAg were positive, and the anti-HBs antibody was negative. Immunoprophylaxis included active immunization, as well as injections of large doses of hepatitis B immunoglobulin (HBIG) given perioperatively to reverse the antigen status. The patient has been anti-HBs antibody positive for more than 10 months since the transplantation. The immunoprophylaxis protocol used has been effective in the prevention of hepatitis B viral reinfection.

Adult↗