Search PubMed⌕ Search

Biomedical subjects

C M Lo

Publications and source records attributed to C M Lo.

At least 109 records · Page 6Linked to original sources
PubMed1998

Cell-substrate separation: effect of applied force and temperature.

We measure the change in cell-substrate separation in response to an upward force by combining two relatively new techniques, Electric Cell-substrate Impedance Sensing (ECIS) to measure average cell-substrate separation, and collagen-coated magnetic beads to apply force to the top (dorsal) surface of cells. The collagen-coated ferric oxide beads attach to integrin receptors in the dorsal surfaces of osteoblastlike ROS 17/2.8 cells. Magnetic force is controlled by the position and the number of permanent magnets, applying an average 320 or 560 pN per cell. Comparing model calculations with experimental impedance data, the junctional resistivity of the cell layer and the average distance between the lower (ventral) cell surface and substrate can be determined. The ECIS analysis shows that these forces produce an increase in the distance between the ventral cell surface and the substrate that is in the range of 10 to 25%. At temperatures of 4 degrees, 22 degrees and 37 degrees C, the measured cell surface-substrate distances without magnetic beads are 84 +/- 4, 45 +/- 2 and 38 +/- 2 nm. The force-induced changes at 22 degrees are 11 +/- 3 and 21 +/- 3 nm for 320 and 560 pN, and at 37 degrees they are 5 +/- 2 and 9 +/- 2 nm. The resulting cell-substrate spring constants at 22 degrees and 37 degrees are thus about 28 and 63 pN nm-1 (dyne cm-1). Using a reasonable range for the number for individual integrin-ligand adhesion bonds gives a range for the spring constant of the individual adhesion bond of from about 10(-3) to 10(-1) pN nm-1. These data also provide evidence that the number of adhesion bonds per cell increases with temperature.

Animals↗
PubMed1998

Posterior or laparoscopic approach for adrenalectomy.

BACKGROUND: The pathologies and size of adrenal lesions removed through the open posterior and laparoscopic routes share remarkable similarities. This study aims at comparing the relative merits of these two approaches. METHODS: Patients with adrenal tumors operated on by posterior approach (n = 56) and transabdominal laparoscopic approach (n = 12) between January 1981 and May 1997 were retrospectively reviewed. RESULTS: The two groups were comparable in terms of age, and the position, size, and weight of the tumor. The operative time of posterior adrenalectomy was significantly shorter than that of laparoscopic adrenalectomy (median 120 minutes versus 160 minutes), whereas laparoscopic adrenalectomy was associated with less parenteral analgesic requirement (median 0 mg versus 225 mg), a shorter hospital stay (median 3 days versus 5 days), and a shorter duration off work (median 11 days versus 26 days). The estimated blood loss was also significantly reduced in the laparoscopic group (median 50 mL versus 150 mL). CONCLUSIONS: Laparoscopic adrenalectomy is replacing posterior adrenalectomy to become the procedure of choice for the majority of patients undergoing adrenalectomy.

Adolescent↗
PubMed1998

Parasite diversity/host age and size relationship in three coral-reef fishes from French Polynesia.

The parasite communities of three coral-reef fish species (Stegastes nigricans, Dascyllus aruanus and Cephalopholis argus) were on Tiahura reef, French Polynesia. The age and growth of each fish was analysed by otolith increment counts and a significant correlation between these variables was found. Stegastes nigricans was parasitised by six adult parasite species, D. aruanus by two adult parasite species and C. argus by five adult parasite species. The most common parasite species were found in all fish size classes. Ectoparasites showed a positive relationship between their abundance and host body length for all three reef fish species. A positive relationship was found only between host size and parasite abundance for common endoparasite species. Parasite species richness, Brillouin's diversity index, and host size and age were positively related. Finally, we discuss the influence of different biological (host diet, host immune response, parasite life-cycle) and ecological factors on parasite community structure in these three reef fishes. Host diet quality seems to be one of the major factors affecting the endoparasite community structure in these reef fishes. Ectoparasite communities seem to be influenced more by biological factors such as, for example, host immunity for the caligid larvae or parasite life-cycle for the gnathiid praniza larvae. In addition, the effect of ecological factors such as cleaning symbiosis on these ectoparasites cannot be dismissed.

Aging↗
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

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↗
PubMed1998

Imaging of follicular dendritic cell tumours of the liver.

Follicular dendritic cell tumour of the liver is a recently recognized entity. To date, only two cases have been described, both in the pathology literature. Histologically, it resembles an inflammatory pseudotumour and immunohistochemical and ultrastructural studies are required for its diagnosis. The ultrasound, computed tomography and angiographic features of two cases of follicular dendritic cell tumour of the liver are described in detail. One of the patients had multiple recurrences of this tumour. The imaging features are very similar to those of hepatocellular carcinoma. As follicular dendritic cell tumour is considered to be of low-grade malignant potential, in contrast to the dismal prognosis for hepatocellular carcinoma, it is important to be able to accurately distinguish between the two types of tumour prior to initiating definitive therapy.

Adult↗
PubMed1998

Paediatric liver transplantation: Queen Mary Hospital experience.

OBJECTIVE: To assess the results of paediatric liver transplantation in our institution. METHODS: From September 1993 to November 1996, 10 living-related liver transplants (LRLT) and 3 reduced-size liver transplants (RSLT) were performed on 12 children at our hospital. The medical records of the patients were reviewed. All patients suffered from end-stage liver disease resulting from biliary atresia with failed Kasai's operations. Their ages at initial transplantation ranged from 8 months to 11 years. Excluding the 2 older children aged 7.5 and 11 years, the remaining patients were aged 10.5 months on the average and weighed 6 to 9.5 kg (mean: 6.8 kg) at the time of initial transplantation. RESULTS: All living donors were discharged on postoperative day 4 to 8 and resumed their previous normal activities. All recipients were alive with normal liver function and growing after a follow-up period of 3-40 months (mean: 21 months). The patient survival rate was 100%. One patient with RSLT had hepatitis of undetermined aetiology and underwent retransplant with a graft from her mother. The graft survival rate was 92%. Postoperative complications included: postoperative bleeding (n = 3), hepatic vein stenosis (n = I), biliary-enteric anastomotic stenosis (n = 3), intestinal perforation (n = I) and portal vein thrombosis (n = I). They were all treated promptly. In all patients, the hepatic artery (diameter ranged from 1.5 to 2.5 mm) anastomosis was achieved by microvascular technique. There was no hepatic artery thrombosis in our patients. CONCLUSION: With technical refinements, early detection and prompt treatment of complications, and advances in immunotherapy, excellent results can be achieved in paediatric liver transplantation.

Biliary Atresia↗
PubMed1997

Extending the limit on the size of adult recipient in living donor liver transplantation using extended right lobe graft.

The feasibility of adult-to-adult living donor liver transplantation (LDLT) is restricted by the adequacy of the graft size. A left lobe graft from a relatively small donor will not meet the metabolic demand of a larger recipient. We report a successful LDLT performed on a 90-kg man using an extended right lobe graft weighing 910 g from his relatively smaller-size brother. The donor-to-recipient body weight ratio was only 0.82. No homologous blood transfusion was required for the donor, and the donor recovered uneventfully except for mild transient hyperbilirubinemia. The graft provided adequate function for the metabolic needs of the recipient despite postoperative septic complications. Both donor and recipient were well with normal liver function at 4 months after operation. LDLT using the extended right lobe liver graft can extend the limit on the size of the adult recipient and may be a viable option even when the donor is relatively small compared with the recipient.

Adult↗
PubMed1997

Endoscopic sphincterotomy: 7-year experience.

The present study documents the indications and results of endoscopic sphincterotomy (ES) performed over 7 years in a surgical endoscopy unit. Potential improvement of results over this time period was analyzed. ES was associated with rare but undesirable morbidity and mortality. Specific improvement of results over time has not been reported. ES was attempted in 706 patients (336 men, 370 women) from 1987 to 1994 and was accomplished in 689 patients (97.6%). Complications occurred in 50 patients (7.1%), 13 of whom required emergency operative intervention. The overall 30-day mortality was 4.7% (n = 33), and procedure-related mortality was 0. 7% (n = 5). There was a significant decrease in hospital mortality (p < 0.01) and operative intervention for procedure-related complications (p < 0.001) after 1990. Procedure-related mortality has been reduced from 1.3% to 0.3% since 1990 (p = 0.1). ES in emergency situations or for malignant biliary obstruction did not adversely affect the outcome. It was concluded that ES can be performed safely in most patients. With increasing experience, procedure-related morbidity and mortality can possibly be reduced.

Adult↗
PubMed1997

Acute biliary pancreatitis: diagnosis and management.

Acute biliary pancreatitis is a serious complication of biliary calculous disease and is associated with significant morbidity and mortality. The role of endoscopic retrograde cholangiopancreatography (ERCP) in the management of acute biliary pancreatitis has been the focus of discussion in recent years. In addition, the exact role of laparoscopic cholecystectomy (LC) in the management of acute biliary pancreatitis has not yet been fully defined. In this report, we evaluated a protocol of emergency ERCP (within 24 hours) for predicted severe attacks, early ERCP (within 72 hours) for predicted mild attacks, and interval LC for management of acute biliary pancreatitis. Between January 1992 and June 1995 a total of 75 patients with acute biliary pancreatitis were managed according to the protocol. Bedside ultrasonography at admission diagnosed 94% of all 64 patients with gallbladder stones, but the sensitivity of visualizing choledocholithiasis was low (19%). Forty-five (60%) of them were predicted to have a severe attack by either Ranson or glucose/urea criteria. Emergency ERCP and endoscopic sphincterotomy (ES) for identifiable common bile duct (CBD) or ampullary stones were performed on all patients predicted to have a severe attack within 24 hours from presentation. An early endoscopic procedure was performed on all patients predicted to have a mild attack within 72 hours from presentation. ERCP was successful in 95% of all patients, and CBD stones were detected in 52 (69%) of them. ES and stone clearance were successful in all of these 52 patients. The morbidity associated with the endoscopic procedure was 3%, and there were no deaths. All except one patient survived the attack of acute pancreatitis, resulting in an overall mortality of 1%. Interval LC was performed on 46 patients with a conversion rate of 4%. The median postoperative hospital stay after LC was 2 days, and there was no major intraoperative or postoperative morbidity or mortality. Our experience suggests that the policy of emergency ERCP for patients with predicted severe disease, early ERCP for patients with predicted mild disease, and interval LC are associated with favorable outcomes in patients with acute biliary pancreatitis. Acute biliary pancreatitis can be managed safely and effectively by a combined endoscopic and laparoscopic approach.

Acute Disease↗
PubMed1997

Early decision for conversion of laparoscopic to open cholecystectomy for treatment of acute cholecystitis.

BACKGROUND: Although recent reports suggest an initial laparoscopic approach to acute cholecystitis, the risk factors and consequences of the failure of an attempt remained unknown. METHODS: A retrospective study of 557 laparoscopic cholecystectomies was undertaken to identify 70 patients (13%) with a clinical diagnosis of acute cholecystitis confirmed by ultrasonography. Patients who required conversion to laparotomy (conversion group) were compared to those with successful laparoscopic cholecystectomy (successful group). RESULTS: Eight of 70 patients (11%) required conversion. The conversion group had significantly more elderly (< or =65 years) patients (88% vs 37%; P = 0.02) and larger gallstones as shown on ultrasonography (25 mm vs 15.5 mm; P = 0.03). Other preoperative factors associated with severe inflammation were not predictive. Conversion was associated with the intraoperative finding of severe adhesions and not with those of empyema of gallbladder or gangrenous cholecystitis. Conversion was made after a median laparoscopic surgery time of 50 minutes. The conversion group required more operation time, more analgesics, a longer recovery time, and a longer hospital stay. In addition, the postoperative complication rate was significantly higher (63% vs 16%; P = 0.009). CONCLUSIONS: Patients who required conversion from laparoscopic to open cholecystectomy for acute cholecystitis are at risk for postoperative complications. In elderly patients with large gallstones, the surgeon should made an early decision to convert if severe adhesions are encountered.

Acute Disease↗
PubMed1997

Liver transplantation in children: the experience of Queen Mary Hospital, Hong Kong.

Seven living-related liver transplants (LRLT) and two reduced-size liver transplants (RSLT) were performed on eight children who suffered from end-stage liver disease, having previously undergone one to three abdominal operations. Their ages at initial transplantation ranged from 8 months to 11 years (mean 35 months, median 12 months). Excluding the two older children aged 7 and 11 years, respectively, the rest of the children weighed 6 to 9.5 kg (mean 7.3 kg) at the time of the initial transplantation. Seven left lateral segments (S2 + 3) and two left lobes (S2 + 3 + 4) were used; of these the smallest graft had a graft-to-recipient body weight ratio of 0.9%. The volunteer living donors were four mothers, two fathers and one sister who were selected after medical and psychiatric evaluations, and their suitability was confirmed by hematological, biochemical, and radiological criteria. During a follow-up period of 3 to 30 months, all eight children are alive and well with normal liver function, one of them having undergone a retransplant LRLT because of hepatitis of undetermined etiology following a RSLT 1.5 years earlier. All seven donors had an uneventful postoperative course and were discharged on day 4 to 7 postoperatively. They have all resumed normal day-to-day activities. There were no complications in the donor group. A variety of complications occurred in the recipients, all of which were overcome. Operating microscope was used to perform all the arterial anastomoses using microvascular techniques. This method has proven to be a major factor in preventing arterial thrombosis even with the smallest of arterial anastomosis where a 1.5-mm diameter recipient artery was anastomosed to a 2.5-mm diameter donor hepatic artery.

Activities of Daily Living↗