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Biomedical subjects

C L Liu

Publications and source records attributed to C L Liu.

At least 109 records · Page 6Linked to original sources
PubMed1999

AO fixateur interne in treating burst fractures of the thoracolumbar spine.

BACKGROUND: A burst fracture of the thoracolumbar junction is an unstable spinal fracture, which is caused by high-energy trauma. There are many methods of treatment, both surgical and nonsurgical, in dealing with spinal burst fractures. The Arbeitsgemeinschaft für Osteosynthesefragen (AO) Fixateur Interne (FI) system was introduced in 1985 for posterior spine surgery with a transpedicular screw system. METHODS: From April, 1989, through December, 1994, we encountered 42 patients with 42 acute burst fractures of the spine; 26 were male and 16 were female, with an average age of 41.2 years. One fracture occurred on T11, seven on T12, 16 on L1, 11 on L2, one on L3, four on L4 and two on L5. According to the Denis classification, there were eight type A, 23 type B, five type C, three type D and three type E fractures. All of these patients received posterior reduction without decompression, posterior short segmental fixation with AO FI instrumentation and posterior fusion. RESULTS: After follow-up for an average of 66.1 months, all fractures were found to have united with residual back pain in only six patients; five patients, including one with nonunion, had back pain without the necessity of medication, and the other one had occasional back pain that was well controlled by medication. The immediate postoperative Cobb's angle improved by an average of 14.2 degrees, and there was an average loss of 3.3 degrees at final follow-up. All patients were neurologically intact at final follow-up except two patients, who were Frankel D. Seven patients had complications during follow-up; one experienced nonunion; four experienced screw breakage, one had screw pullout, and the other experienced breakage of the connecting rod. CONCLUSIONS: From our retrospective study, the outcome of burst fracture of the spine treated with AO FI instrumentation system was satisfactory.

Adult↗
PubMed1999

[Developments of the theory of skeletal adaptation to mechanical loading].

The primary mechanical function of bone is to provide rigid levers for limbs to act against mechanical loading and gravity, and to remain as light as possible to allow efficient locomotion. There are increasing evidence that mechanical loading is an important, if not the most important, factor influences bone mass and architecture. Many bones are exposed to thousands of repetitive loads every day, which always cause strains. Unusual strain distributions, high strains, and high strain rates seem to be particularly osteogenic. Bone modeling can increase bone strength and mass, bone remodeling can conserve or reduce them, and each can be turned ON or OFF in response to its own threshold range of bone strains. During growth and development, the skeleton optimizes its architecture and strength by (re)modeling to adapt to the largest voluntary loads on bones. The loads come from muscles, not body weight. A new standard of defining osteoporosis might relate bone strength to muscle strength that concerns the osteopenias pathogenesis and its severity, and it would be useful for prevention and cure of osteoporosis.

Aerospace Medicine↗
PubMed1998

High tissue content of urokinase plasminogen activator (u-PA) is associated with high stromal expression of u-PA mRNA in poorly differentiated serous ovarian carcinoma.

Urokinase plasminogen activator (u-PA) plays a pivotal role in tissue degradation during tumor spread and metastasis. We have quantitated u-PA in tissue homogenates of 31 serous ovarian tumors and localized u-PA and its mRNA in tissue sections of 26 serous ovarian tumors. The content of u-PA was higher in malignant than in benign tumors, with the highest levels being found in poorly differentiated cancers. In tissue sections, the u-PA mRNA was hybridized with a radiolabeled RNA probe. Signals were almost exclusively found in the epithelium in benign and borderline tumors and in well-differentiated cancers. Poorly differentiated tumors and metastases exhibited prominent stromal expression of u-PA mRNA, whereas epithelial expression was weak or absent. Immuno-histochemical staining co-localized u-PA antigen with its mRNA in the epithelium of benign and borderline tumors and in well-differentiated cancers. Poorly differentiated malignant tumors showed extensive immunostaining in the epithelium in addition to stromal staining. The u-PA mRNA-expressing and u-PA-immunostained cells in the stroma were not tumor cells since no cells in the stroma were positive for cytokeratin. Poorly differentiated tumors had increased numbers of stromal macrophages (CD68), and they co-localized with some of the u-PA-positive cells. The presence of u-PA antigen and the absence of u-PA mRNA in tumor epithelium of poorly differentiated tumors and metastases together with the presence of u-PA mRNA in the stroma suggests production in stromal cells and subsequent binding to receptor sites in tumor cells.

Cell Transformation, Neoplastic↗
PubMed1998

Separation of proteins and viruses using two-phase aqueous micellar systems.

We discuss the utilization of a novel two-phase aqueous nonionic micellar system for the purification and concentration of biomolecules, such as proteins and viruses, by liquid-liquid extraction. The nonionic surfactant n-decyl tetra(ethylene oxide), C10E4, phase separates in water into two coexisting aqueous micellar phases by increasing temperature. The mild interactions of the C10E4 nonionic surfactant with biomolecules, combined with the high water content of the two coexisting micellar phases, suggest the potential utility of two-phase aqueous C10E4 micellar systems for the purification and concentration of biomolecules. In this paper, we review our recent experimental and theoretical studies involving the partitioning of several water-soluble proteins, including cytochrome c. soybean trypsin inhibitor, ovalbumin, bovine serum albumin, and catalase, in the two-phase aqueous C10E4 micellar system. In addition, we present results of our preliminary experimental investigation on the partitioning of bacteriophages, including phiX174, P22, and T4.

Bacteriophages↗
PubMed1998

Characterization of a novel covalent monoadduct on the RNA overhang of an RNA-DNA hybrid induced by antitumor antibiotic neocarzinostatin.

Neocarzinostatin chromophore (NCS-chrom) has been found previously to induce thiol-dependent abasic site formation and cleavage on the RNA strand of RNA-DNA hybrids. When a four-base nucleotide was deleted from the 5' end of the DNA strand, however, an unexpected product with slow mobility, potentially a drug adduct or interstrand cross-linked material, was observed instead. End-labeling of the RNA and DNA strands showed that only the RNA strand is present in the product. The product, isolated from a denaturing polyacrylamide gel, has a fluorescence spectrum similar to that of activated NCS-chrom, and thiols with different charges give rise to products with various mobilities on the gel, indicating that the product consists of a drug adduct with NCS-chrom and thiol attached to the RNA strand of the hybrid. Mass spectroscopic (MS) analysis shows that it is a monoadduct. Chemical sequencing of 5'- and 3'-end-labeled monoadduct and MS/MS data show that drug is attached only to the U9 of the RNA in the hybrid 5'-r(CACAGAAUU9CG)/5'-d(TTCTGTG). Unlike most other DNA adducts and cross-linked products found previously, this adduct can be formed readily in the presence of atmospheric oxygen. 2'-O-Methyl and 2'-H substitutions and nucleotide replacements on the 4-base RNA overhang affect monoadduct formation to different extents, reflecting the existence of a tight three-dimensional binding pocket for the activated drug. Stability of drug adduct to heat and aniline-HOAc treatment suggest that the drug is covalently bound to the ribose of U9. Since no deuterium isotope selection effect was observed for C-1' of U9, it is possible, although not required, that the drug abstracts H from another hydrogen source on the sugar of the targeted ribonucleotide.

Aerobiosis↗
PubMed1998

Biliary complications after hepatic resection: risk factors, management, and outcome.

OBJECTIVE: To identify the risk factors for the development of biliary complications after hepatic resection and to evaluate management in relation to the outcomes of these patients. DESIGN: Biliary complications are a common cause of major morbidity after hepatic resection. A survey was made of all patients undergoing hepatic resection at 1 institution. Perioperative risk factors related to the development of biliary complications were identified using multivariate analysis. Management and outcome were analyzed also. SETTING: A tertiary referral center. PATIENTS: From January 1, 1989, to October 31, 1995, 347 consecutive patients underwent 229 major and 118 minor hepatic resections. MAIN OUTCOME MEASURE: Development of postoperative biliary complications. RESULTS: Biliary complications developed in 28 (8.1%) of 347 patients; these complications carried high risks for liver failure (35.7%) and operative mortality (39.3%). Stepwise logistic regression analysis identified increasing age, higher preoperative white blood cell count, left-sided hepatectomy, and prolonged operation time as the independent predictors of development of biliary complications. Conservative treatment or nonoperative measures alone, such as percutaneous drainage or endoscopic therapy, were effective in treating the complication in 13 of 19 patients, but those who required reoperation had a high mortality rate (7 [77.8%] of 9 patients). Patients with demonstrable leakage from the common bile duct or its bifurcation tended to have poor outcomes. CONCLUSIONS: Biliary complications are a common and serious cause of morbidity after hepatic resection. Preresection cholangiography for finding biliary tract anomaly is recommended before left-sided hepatectomy. Although nonoperative measures are the preferred approach for selected patients with biliary complications, those with demonstrable leakage from the common bile duct or its bifurcation have a grave prognosis and may benefit from early surgical intervention.

Adult↗
PubMed1998

Postoperative adjuvant chemotherapy after curative resection of hepatocellular carcinoma: a randomized controlled trial.

OBJECTIVE: To study the effect of adjuvant chemotherapy after curative hepatic resection in patients with hepatocellular carcinoma. DESIGN: A randomized controlled trial. SETTING: A tertiary referral center. PATIENTS: During a 54-month period, 142 patients with hepatocellular carcinoma underwent hepatic resection at 1 institution. Sixty-six patients who survived the operation and had no demonstrable evidence of residual disease on ultrasonographic examination and hepatic angiographic testing at 1 month after surgery agreed to participate in the study. The median follow-up time was 28.3 months. INTERVENTION: Thirty patients received a combination of intravenous epirubicin hydrochloride (8 doses of 40 mg/m2 each at 6-week intervals) and transarterial chemotherapy using an emulsion of iodized oil and cisplatin (3 courses with a maximum dose of 20 mL each at 2-month intervals). Thirty-six patients had no adjuvant treatment. MAIN OUTCOME MEASURES: Recurrence rate and disease-free survival. RESULTS: A total of 138 courses of intravenous epirubicin was given to the 30 patients. Sixty-one courses of transarterial chemotherapy were given to only 29 of the 30 patients assigned to the treatment group, because the hepatic artery in 1 patient was thrombosed. Six patients (20%) had chemotherapy-related complications with no mortality. Twenty-three of 30 patients in the treatment group and 17 of 36 patients in the control group had recurrences (P=.01). Patients who received adjuvant chemotherapy had a higher incidence of extrahepatic metastases (11 patients vs 5 patients; P=.03). The respective disease-free survival rates at 1, 2, and 3 years were 50%,36%, and 18% for the treatment group and 69%, 53%, and 48% for the control group (P=.04). CONCLUSION: In a group of patients who underwent curative resection of hepatocellular carcinoma, postoperative adjuvant chemotherapy using the present regimen was associated with more frequent extrahepatic recurrences and a worse outcome.

Antineoplastic Agents↗
PubMed1998

Endoscopic retrograde cholangiopancreatography and endoscopic endoprosthesis insertion in patients with Klatskin tumors.

OBJECTIVE: To assess the value and the associated morbidity of endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic endoprosthesis insertion in the treatment of patients with Klatskin tumors. DESIGN: Retrospective study. SETTING: A tertiary referral center. PATIENTS: Fifty-five consecutive patients with Klatskin tumors diagnosed through typical cholangiographic and computed tomographic findings. INTERVENTION: Standard ERCP with endoscopic stenting technique was employed. Once the diagnosis of Klatskin tumor was confirmed on cholangiogram, endoscopic stenting was performed to bypass the stricture. Multiple stents were inserted if necessary to ensure adequate biliary drainage. MAIN OUTCOME MEASURES: The success rate of ERCP and endoscopic endoprosthesis insertion, successful drainage rate, early complications of endoscopic procedure, procedure-related mortality, and long-term outcome of endoprosthesis. RESULTS: Of the 55 patients, cholangiography was performed in 53 (96%). In the 49 patients in whom endoscopic stenting was attempted, the procedure was successful in 28 patients (57%) at the first attempt and 8 patients (16%) at the second attempt, resulting in a cumulative success rate of 73%. Only 20 of these patients had satisfactory biliary drainage, resulting in an overall successful drainage rate of 41%. Early complications, including acute cholangitis, acute pancreatitis, and postpapillotomy bleeding occurred in 14 patients (25%). Three patients (5%) died of procedure-related complications. The median patency of the first endoprosthesis inserted was 1 week (range, 0-8 wk). The 30-day mortality rate was 18%. CONCLUSIONS: In patients with Klatskin tumors, ERCP and endoscopic endoprosthesis insertion have a low successful drainage rate, are associated with high morbidity and procedure-related mortality, and have a limited effect on long-term palliation. Endoscopic retrograde cholangiopancreatography and endoscopic endoprosthesis insertion have a limited value in the management of patients with Klatskin tumors.

Adult↗
PubMed1998

Primary biliary stones: diagnosis and management.

To review the results of treatment of primary biliary stones, 96 consecutive patients managed from 1991 to 1996 were studied retrospectively. Acute cholangitis and abdominal pain were the presenting symptoms in 57 patients (59%) and 29 patients (30%), respectively. Fifty-four patients (56%) had a history of biliary surgery. Endoscopic retrograde cholangiopancreatography, ultrasonography, and computed tomography were frequently employed for diagnosis of primary biliary stones and were performed on 84 patients (88%), 90 patients (94%), and 89 patients (93%), respectively. Intrahepatic stones were identified in 91 patients (95%) and biliary strictures in 34 patients (35%). Concomitant cholangiocarcinoma occurred in 15 patients (16%). Hepatic resection was required in 55 patients (57%) for removal of an atrophic liver lobe or a segment related to repeated infection, biliary strictures, liver abscesses, or cholangiocarcinoma. Intraoperative choledochoscopy was routinely performed in all patients to detect, remove, or confirm clearance of biliary stones. A hepaticocutaneous jejunostomy (HCJ) was constructed in 70 patients (73%) to facilitate postoperative choledochoscopic examination or biliary stone extraction. Twenty-two patients (23%) had residual stones and required postoperative choledochoscopic extraction. Complete eradication of residual stones was achieved in all patients. Postoperative morbidity occurred in 28 patients (29%), and there was one hospital death (a patient with cholangiocarcinoma). With a median follow-up of 26 months (range 2-62 months), stones recurred in three patients. In conclusion, the early results of treatment of primary biliary stones were satisfactory owing to a systematic, aggressive approach that consisted of hepatic resection, frequent construction of an HCJ, and postoperative choledochoscopy.

Adult↗
PubMed1998

Ruptured hepatocellular carcinoma as a complication of transarterial oily chemoembolization.

BACKGROUND: Transarterial oily chemoembolization (TOCE) is frequently employed as a non-operative treatment for hepatocellular carcinoma (HCC). Serious complications of TOCE are well known but ruptured HCC as a fatal complication of TOCE has not been reported previously. METHODS: A retrospective study was performed on all patients who received TOCE for treatment of HCC from January 1989 to October 1996; the complication of ruptured HCC within 2 weeks from the procedure was recorded. RESULTS: During the study period, 391 patients received a total of 1443 sessions of TOCE (mean 3.7 sessions per patient) for the treatment of HCC, with an overall median survival of 10.4 months. Six patients developed ruptured tumour within 2 weeks after TOCE, resulting in an overall incidence of 1.5 per cent per patient or 0.4 per cent per procedure. All except one patient died 1-25 days after tumour rupture. Factors common to these six patients included: (1) male sex; (2) large tumour size (range 8-17 cm in diameter); (3) tumour located in the right lobe of the liver; (4) tumour ruptured after the first session of TOCE; and (5) TOCE performed as primary treatment without previous hepatic resection. CONCLUSION: Ruptured HCC is a serious complication of TOCE although the incidence is low. It occurred predominantly in men after the first session of TOCE for a large irresectable tumour of the right lobe.

Carcinoma, Hepatocellular↗
PubMed1998

Prolonged survival in selected patients following surgical resection for pulmonary metastasis from hepatocellular carcinoma.

BACKGROUND: Pulmonary metastasis is the commonest site of extrahepatic spread from hepatocellular carcinoma (HCC). The aim of the present study was to evaluate the efficacy of surgical management in patients with solitary pulmonary metastases from HCC. METHODS: This was a retrospective study of patients with HCC admitted for hepatectomy from July 1972 to June 1995. The records of patients who had a pulmonary resection for histologically proven pulmonary recurrence after curative hepatectomy were selected for analysis. RESULTS: In the study interval, 380 patients with HCC underwent hepatectomy. Some 48 patients (12.6 per cent) developed pulmonary metastases documented pathologically or radiologically. Nine (seven men and two women) were suitable for curative pulmonary resection. The median disease-free survival between hepatectomy and appearance of the lung metastasis was 21 months. The median survival after pulmonary resection was 42 months, and the 1-, 2- and 5-year survival rates were 100, 78 and 67 per cent respectively. CONCLUSION: Pulmonary resection for metastases from HCC resulted in long-term survival in these highly selected patients.

Adult↗
PubMed1998

Intra-abdominal follicular dendritic cell tumour: a rare tumour in need of recognition.

AIMS: Neoplasms of follicular dendritic cells are uncommon and the majority of them occur in lymph nodes. Rarely, they may occur inside the abdominal cavity. We describe two examples of intra-abdominal follicular dendritic cell (FDC) tumour. One involved the liver and the other involved the ampulla of Vater. Our aims are to complement the current understanding on this disease and to alert histopathologists and clinicians to this rare entity. MATERIALS AND RESULTS: The clinical and radiological findings of the two cases of intra-abdominal follicular dendritic cell tumours were reviewed. The resected specimens were examined macroscopically and microscopically. Immunohistochemical studies, ultrastructural examination and in situ hybridization for Epstein-Barr virus were also performed. Both tumours could not be accurately diagnosed before pathological examination of the resected specimens. The soft to slightly firm consistency of the tumours resembled that of fixed brain tissue, and was distinctly different from hepatocellular carcinoma or pancreatic carcinoma. The fascicular arrangement of syncytial plump to spindle cells in a background of mixed inflammatory cells was the initial clue to the diagnosis, which was confirmed by the immunoreactivity of the tumour cells to follicular dendritic cell markers (CD21 and CD35), and by the demonstration of focal intercellular desmosome-like junctions between the complex cytoplasmic processes of the tumour cells. The tumour cells in the liver tumour also showed presence of Epstein-Barr virus on in situ hybridization study. CONCLUSIONS: Awareness of the entity and the ability to recognize this tumour by histopathologists are emphasized because the tumour closely mimics a wide variety of other tumours and tumour-like lesions. Similar to the other reported FDC tumours of the liver, our case of hepatic follicular dendritic cell tumour is also positive for Epstein-Barr virus, suggesting that the virus may play a role in its pathogenesis.

Adult↗
PubMed1998

Prospective randomized study of early versus delayed laparoscopic cholecystectomy for acute cholecystitis.

OBJECTIVE: A prospective randomized study was undertaken to compare early with delayed laparoscopic cholecystectomy for acute cholecystitis. SUMMARY BACKGROUND DATA: Laparoscopic cholecystectomy for acute cholecystitis is associated with high complication and conversion rates. It is not known whether there is a role for initial conservative treatment followed by interval elective operation. METHOD: During a 26-month period, 99 patients with a clinical diagnosis of acute cholecystitis were randomly assigned to early laparoscopic cholecystectomy within 72 hours of admission (early group, n = 49) or delayed interval surgery after initial medical treatment (delayed group, n = 50). Thirteen patients (four in the early group and nine in the delayed group) were excluded because of refusal of operation (n = 6), misdiagnosis (n = 5), contraindication for surgery (n = 1), or loss to follow-up (n = 1). RESULTS: Eight of 41 patients in the delayed group underwent urgent operation at a median of 63 hours (range, 32 to 140 hours) after admission because of spreading peritonitis (n = 3) and persistent fever (n = 5). Although the delayed group required less frequent modifications in operative technique and a shorter operative time, there was a tendency toward a higher conversion rate (23% vs. 11%; p = 0.174) and complication rate (29% vs. 13%; p = 0.07). For 38 patients with symptoms exceeding 72 hours before admission, the conversion rate remained high after delayed surgery (30% vs. 17%; p = 0.454). In addition, delayed laparoscopic cholecystectomy prolonged the total hospital stay (11 days vs. 6 days; p < 0.001) and recuperation period (19 days vs. 12 days; p < 0.001). CONCLUSIONS: Initial conservative treatment followed by delayed interval surgery cannot reduce the morbidity and conversion rate of laparoscopic cholecystectomy for acute cholecystitis. Early operation within 72 hours of admission has both medical and socioeconomic benefits and is the preferred approach for patients managed by surgeons with adequate experience in laparoscopic cholecystectomy.

Acute Disease↗
PubMed1998

Laparoscopy and laparoscopic ultrasonography avoid exploratory laparotomy in patients with hepatocellular carcinoma.

OBJECTIVE: This prospective study evaluates the value of laparoscopy and laparoscopic ultrasonography (USG) in avoiding exploratory laparotomy in patients with hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: Laparotomy and intraoperative USG is the gold standard to determine the resectability of HCC. No palliation can be offered to patients found to have unresectable disease, and the surgical exploration causes morbidity. METHODS: From June 1994 to June 1996, 110 of 370 patients (30%) with HCC were considered candidates for possible hepatic resection. Preoperative liver function was assessed using Child-Pugh grading and indocyanine green retention test. The extent of disease was evaluated with radiologic studies, including percutaneous USG, computerized tomography scan, and hepatic angiogram. Nineteen patients were excluded from the study because of previous upper abdominal surgery (n = 12), ruptured tumors (n = 4), refusal by patients (n = 2), and instrument failure (n = 1). Laparoscopy and laparoscopic USG was performed on 91 patients immediately before a planned laparotomy aiming at hepatic resection. Laparotomy was aborted when definite evidence of unresectable disease was found on laparoscopic examination. RESULTS: The median time required for laparoscopy and laparoscopic USG was 30 minutes (range, 10 to 120 minutes). Fifteen patients had evidence of unresectable disease on laparoscopic examination. Among the remaining 76 patients who underwent laparotomy, 9 had exploration only and 67 underwent hepatic resection. Thus, exploratory laparotomy was avoided in 63% of patients with unresectable disease. The laparoscopic examination failed to confirm unresectable disease more often when the tumor was >10 cm in diameter. The procedure accurately assessed the adequacy of the liver remnant and the presence of intrahepatic metastases, but it was less sensitive in determining the presence of tumor thrombi in major vascular structures and the extent of invasion of adjacent organs. When unresectable disease was detected without the need for a laparotomy, the postoperative recovery was faster, and the nonoperative treatment for the tumor could be initiated earlier. CONCLUSIONS: Laparoscopy with laparoscopic USG avoids unnecessary laparotomy in patients with HCC and should precede a planned laparotomy aiming at hepatic resection.

Adolescent↗