Electron transfer components of wild-type and photosynthetic mutant strains of Scenedesmus obliquus D3.
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Anthocyanins↗
Biomedical subjects
J Wong
Publications and source records attributed to J Wong.
Competitive hapten-antibody binding: solution of the binding equation.
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Antibodies↗
Esophageal cancer surgery: the value of controlled clinical trials.
Prospective randomized controlled trials (RCT) in esophageal cancer were reviewed. Their value and significance in the areas of multimodality therapy, lymphadenectomy, surgical techniques, palliative treatments, and perioperative management were evaluated. Much has been gained through RCT in the management of esophageal cancer, and RCT is the most reliable scientific method in clinical investigations. Problems in the conduct of such trials include lack of expertise by surgeons, lack of patients, lack of funding, and methodologic and ethical problems. These obstacles could be overcome and more well-conducted RCTs encouraged.
Adenocarcinoma↗
Induction of angiogenesis by implantation of encapsulated primary myoblasts expressing vascular endothelial growth factor.
BACKGROUND: We previously demonstrated that intramuscular implantation of primary myoblasts engineered to express vascular endothelial growth factor (VEGF) constitutively resulted in hemangioma formation and the appearance of VEGF in the circulation. To investigate the potential for using allogeneic myoblasts and the effects of delivery of VEGF-expressing myoblasts to non-muscle sites, we have enclosed them in microcapsules that protect allogeneic cells from rejection, yet allow the secretion of proteins produced by the cells. METHODS: Encapsulated mouse primary myoblasts that constitutively expressed murine VEGF164, or encapsulated negative control cells, were implanted either subcutaneously or intraperitoneally into mice. RESULTS: Upon subcutaneous implantation, capsules containing VEGF-expressing myoblasts gave rise to large tissue masses at the implantation site that continued to grow and were composed primarily of endothelial and smooth muscle cells directly surrounding the capsules, and macrophages and capillaries further away from the capsules. Similarly, when injected intraperitoneally, VEGF-producing capsules caused significant localized inflammation and angiogenesis within the peritoneum, and ultimately led to fatal intraperitoneal hemorrhage. Notably, however, VEGF was not detected in the plasma of any mice. CONCLUSIONS: We conclude that encapsulated primary myoblasts persist and continue to secrete VEGF subcutaneously and intraperitoneally, but that the heparin-binding isoform VEGF164 exerts localized effects at the site of production. VEGF secreted from the capsules attracts endothelial and smooth muscle cells in a macrophage-independent manner. These results, along with our previous results, show that the mode and site of delivery of the same factor by the same engineered myoblasts can lead to markedly different outcomes. Moreover, the results confirm that constitutive delivery of high levels of VEGF is not desirable. In contrast, regulatable expression may lead to efficacious, safe, and localized VEGF delivery by encapsulated allogeneic primary myoblasts that can serve as universal donors.
Animals↗
Squamous esophageal cancer--introduction.
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Carcinoma, Squamous Cell↗
Risk analysis in resection of squamous cell carcinoma of the esophagus.
A study of risk factors that affect morbidity and mortality in 523 patients with squamous cell cancer of the esophagus who had one-stage resection was undertaken. The 30-day and hospital mortality rates were 5.0% and 15.5%, respectively. Pulmonary complications, malignant cachexia, and surgical complications accounted for 42%, 25%, and 21% of hospital deaths, respectively. Major pulmonary complications occurred in 23% of patients. Multivariate analysis identified six factors that predicted major pulmonary complications: age, mid-arm circumference, percent of predicted FEV1, abnormal chest radiograph, amount of blood loss, and palliative resection. Three risk groups of pulmonary complications were identified: low, median, and high risk group with complications in 3%, 17%, and 43% of patients, respectively. Significantly, patients with curative resection had a lower hospital mortality rate (9%) than those with palliative resection (20%), p = 0.001. Patients with stage I, IIa, or IIb disease had a lower hospital mortality rate (9%) than those with stage III or IV disease (18%), p = 0.026. Multivariate analysis identified six factors that predicted hospital death: age, mid-arm circumference, history of smoking, incentive spirometry, number of stairs climbed, and amount of blood loss. Three risk groups of hospital death were identified: low, median, and high risk groups with death in 7%, 30%, and 38%, respectively. Anastomotic leakage rate was 4%. Technical faults were identified in 53% of patients with leakage. Together with other surgical complications, a presumed or apparent technical error was noted in 63% of patients. The identification of high-risk patients and prevention of technical faults can help improve surgical outcome.
Carcinoma, Squamous Cell↗
Operable esophageal carcinoma: current results from Hong Kong.
Over an 11-year period 1158 patients with esophageal cancers were managed by the Department of Surgery, The University of Hong Kong, Queen Mary Hospital, 857 (74.0%) of whom had confirmed squamous cell carcinoma. Operation was carried out in 76.5% of patients: 25.4% underwent curative resection, 36.2% underwent palliative resection, 13.8% had bypass operations, and 1.2% had a simple exploration. In the resection group, the mean age was 62.6 years with a strong male predominance of 6.4:1.0. Most patients were heavy smokers and heavy drinkers; 27.9% had increased pulmonary risks, and 8.3% had increased cardiac risks for resection. Most (56%) of the tumors were located in the middle third of the esophagus; 70.4% of patients had operative stage III disease, and 7.2% had stage IV disease. The 30-day mortality and hospital mortality after resection were 4.9% and 15.9%, respectively. The primary cause of 30-day mortality was cardiopulmonary-related complications (65.2%), and the commonest causes for hospital deaths were from pulmonary complications (40.0%) and advancing malignancy (23.6%). The median survivals for stages I, IIA, IIB, III, and IV were 83.5, 24.3, 37.8, 8.6, and 5.0 months, respectively. Of the survivors, at 1, 6, and 12 postoperative months, respectively, 63%, 76%, and 83% of patients were able to take a full solid meal similar to the normal diet consumed before their disease.
Adult↗
Balloon occlusion scintigraphy of aortopulmonary collaterals.
We evaluated two children with pulmonary atresia for coil embolization of aortopulmonary collateral vessels after placement of palliative aortopulmonary shunts. To determine vessel distribution and lung perfusion prior to collateral embolization, perfusion scintigraphy with technetium 99m-labeled macroaggregated albumin assessed pulmonary blood flow before and after balloon wedge catheter occlusion of the collaterals. In the first patient we found no perfusion defect during collateral occlusion, and we proceeded with embolization. In the second child, perfusion scintigraphy during occlusion of the collateral vessels demonstrated a filling defect, and embolization was not performed, thus avoiding the creation of a potential perfusion defect in this patient. Assessing the physiologic significance of aortopulmonary collateral vessels by utilizing temporary balloon occlusion of the collateral vessels and concurrent perfusion scintigraphy as an adjunct to selective angiography can provide a significant contribution to the safety and accuracy of coil embolization.
Aorta↗
Benign breast disorders in nonwestern populations: Part I--Benign breast disorders in Chinese women.
Experience with benign breast disorders has been analyzed in 3 nonwestern populations: Hong Kong, India, and Northern Nigeria. Similarities to and differences from Western experience are found, but of great interest are notable differences between these populations which, as yet, lack explanation. All show "fibroadenosis" and fibroadenoma as common conditions, but the frequency with which phyllodes tumor is diagnosed varies between different centers in India as well as between different racial groups. Tuberculosis is another interesting example--wide differences in the frequency of breast infection are found although tuberculosis itself is common in all 3 countries. The value of prospective studies was shown when mastalgia was studied in this way in India. Often considered a "Western" affliction, these authors have been able to study 112 cases of mastalgia and found it to be twice as common as cancer as a presentation. These differing experiences between populations have been little explored and must hold promise for unravelling some of the enigmas of benign breast disorders in all countries.
Adolescent↗
Symptomatic nonparasitic cysts of the liver.
A retrospective study of 14 patients who had symptomatic congenital liver cysts managed at the Department of Surgery, University of Hong Kong at Queen Mary Hospital together with a literature review was conducted to evaluate the current surgical practice for the condition. Seven patients were managed either expectantly (N = 5) or by percutaneous aspiration (N = 2). Surgery which included total cystectomy (N = 3), external drainage (N = 1), and marsupialization with (N = 2) or without (N = 1) fenestration was done for the remaining 7 patients, among whom 1 developed bleeding after total cystectomy. While percutaneous aspiration provides adequate symptomatic palliation in selected patients, eventual recurrent cyst formation is frequent, especially when the cyst exceeds 10 cm in diameter. Despite technological advances, the presence of biliary communication and malignancy could not be accurately determined preoperatively. Careful examination of the cyst cavity at surgery remains the most reliable guide. Drainage into the peritoneal cavity in the presence of infection or bile content provides satisfactory drainage with minimal morbidity and mortality. Since total cystectomy could be done safely without partial hepatectomy, it can even be considered in patients with deeply-seated lesions. The role of aggressive hepatic resection or liver transplantation for the management of liver cysts remains to be validated by further clinical evaluation.
Adult↗
Current management of intrahepatic stones.
A high incidence of intrahepatic stones occurs in East Asia. The surgical management of intrahepatic stones is problematic because it is difficult to locate and remove all the stones and relieve the accompanying biliary strictures. Consequently, the rate of recurrent cholangitis is high. Many new techniques have been introduced to locate, fragment, and retrieve gallstones. Operative procedures to relieve biliary strictures have also undergone development. These new procedures and techniques have been applied to intrahepatic stones. The initial results are good. Whether these good results can be maintained in the long-term remains to be seen.
Bile Ducts, Intrahepatic↗
Hepatectomy for large hepatocellular carcinoma: the optimal resection margin.
The necessary resection margin (RM) for cure during hepatectomy for hepatocellular carcinoma (HCC) remains conjectural. From January, 1972 to June, 1988, a total of 96 patients who had complete macroscopic extirpation of their large tumor (greater than or equal to 5 cm in largest diameter) were studied retrospectively to determine the macroscopic distance of RM required to secure histological disease clearance. Positive histological RM, which was found in 31 (32.3%) patients, had significantly compromised both disease-free survival (p less than 0.04) and overall survival (p less than 0.006) of these patients. Among the 65 patients with detailed measurement of macroscopic RM, a significant reduction of residual histological disease was observed when a 0.5 cm margin had been established (p less than 0.05). Further extension of margin had no additional benefit. The presence of microsatellite (p less than 0.03) and multiple tumor nodules (p less than 0.03) was associated with an increased risk of positive histological margins among the 15 pathological parameters evaluated, including macroscopic RM. Since measurement of RM is an unreliable guide, histological confirmation is the only means for establishing the diagnosis of complete tumor clearance. Within safety limits dictated by anatomical factors and severity of underlying cirrhosis, aggressive surgery should be offered for patients with large HCC; however, resection is not advisable unless a 0.5 cm margin can be secured with certainty, especially for multinodular lesions.
Adult↗
Recurrent pyogenic cholangitis: current management.
Successful treatment of recurrent pyogenic cholangitis depends on the ability to delineate the pathology of the entire biliary system and to eradicate all stones, strictures, and destroyed liver segments. Recent advances in imaging techniques and stone fragmentation technology have been applied successfully in the management of this condition. Apart from direct cholangiography and ultrasonography, valuable information can be obtained from computed tomography which is particularly helpful in patients with recurrent disease after previous biliary surgery. Application of electrohydraulic lithotripsy in this disease solves the problem of difficult stone retrieval due to large size, impaction behind relative strictures and inside angulated segmental bile ducts. Together with construction of a hepaticocutaneous jejunostomy serving as a permanent access to the bile duct, it is anticipated that the incidence of recurrence and reoperation in the future can be reduced.
Bacterial Infections↗
Anastomotic leakage after resection and bypass for esophageal cancer: lessons learned from the past.
A retrospective study of anastomotic leakage has been undertaken in 730 patients who had resection or bypass for carcinoma of the esophagus during the period 1964-1982 at the Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong. Partial or complete gangrene of the substitute loop also resulting in anastomotic disruptions were excluded from this series. Anastomotic leakage due to suture line failure occurred in 182 patients (24.9%). Two factors were found by multivariate analysis to influence leakage: the type of operation and the choice of organ used as substitute. Leakage occurred more than twice as often in bypass (42.7%) than in resection (18.3%). When the substitute used for reconstruction was viable, jejunum was associated with the lowest incidence of leakage followed by whole stomach, distal stomach, and colon in that order. The risk of leakage for any combination of the type of operation (resection or bypass) and substitute loop used was calculated. The probability of leakage was lowest when a resection was performed and jejunum was used as substitute. In view of the simplicity and relative safety of using the whole stomach, esophagectomy followed by gastric reconstruction is still the procedure of choice for the majority of patients. A bypass procedure using colon as substitute has the highest leakage rate. A low leakage rate should now be obtained, otherwise nonoperative therapy has a legitimate claim as the preferred alternative treatment modality.
Esophageal Neoplasms↗
Hepatic resection for small hepatocellular carcinoma: the Queen Mary Hospital experience.
The clinico-pathological features and long-term results of 39 patients with resected small hepatocellular carcinoma (HCC) managed over 19 years in Hong Kong were retrospectively studied (mean diameter +/- standard deviation: 3.6 +/- 1.3 cm). Thirty-one patients were symptomatic and the majority (n = 33) of them had cirrhosis. When compared with 182 patients with large HCC operated within the same period, these patients with small HCC had a significantly higher incidence of spontaneously ruptured lesions (p less than 0.03). Following hepatic resection-major lobectomy (n = 19) and limited hepatic resection (n = 20), operative and hospital deaths occurred in 7.7% and 12.8% of patients, respectively. The size of the lesion had little influence on prognosis. The overall survival at 1, 3, and 5 years was 59%, 28%, and 11%, respectively, which was comparable to patients with large HCC greater than or equal to 5 cm. Further stratification of these 39 patients according to a diameter of greater than 3 cm (n = 22) or less than or equal to 3 cm (n = 17) showed no difference in long-term outcome. When compared with large tumors, frequent encapsulation (p less than 0.04) and less venous permeation (p less than 0.03) were encountered in small HCC. As the extent of hepatectomy had no effect on long-term outcome, limited hepatectomy for patients with small HCC is probably the procedure of choice. A 1 cm macroscopic resection margin is apparently adequate to ensure complete histological disease clearance.
Adult↗
Endosonography in patient selection for surgical treatment of esophageal carcinoma.
A prospective study was carried out to examine the usefulness of endosonography (ES) in the pre-operative staging of patients with carcinoma of the esophagus, and its relevance in predicting resectability and the type of resection. The results of ES were compared with staging by conventional pre-operative methods and with operative staging according to the new American Joint Commission of Cancer staging classification. Of the 89 patients studied, 62 had a resection, 22 a bypass operation, and 5 had no operation. ES examination was unsuccessful in 19 patients because of complete or near complete tumor obliteration of the esophageal lumen and was incomplete in 13 patients because of distal tumor obstruction. These 32 patients accounted for 36% of all ES examinations, 27% of resection group, 55% of bypass group, and 60% of no operation group. The 45 patients who had a satisfactory ES examination and who had underwent a transthoracic resection were analyzed. The sensitivity and specificity of ES in detecting the depth of esophageal involvement were 89% and 96%, respectively, and for lymph node metastasis were 85% and 86%, respectively. However, ES was neither sensitive in detecting extra-esophageal infiltration to mediastinal organs nor was it able to determine the extent of intra-abdominal spread. The accuracy of pre-operative staging was 82% by ES compared with 51% by conventional staging (p < 0.001). ES correctly identified more advanced stage of disease in 14 (31%) patients as compared with conventional staging. On the evaluation of resectability, which was based on conventional investigations without ES, the result was unaffected even if the additional findings of ES were available.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenocarcinoma↗
Intrahepatic cholangiocarcinoma.
Intrahepatic cholangiocarcinoma is an uncommon neoplasm of liver compared with hepatocellular carcinoma. Hepatic resection seems to provide the only chance for therapeutic success. The records of 77 patients with intrahepatic cholangiocarcinoma treated over a 28-year period were studied to determine demographics, clinical features, laboratory findings, diagnostic tests, operative management, and results of therapy. Survival was analyzed according to three treatment groups: conservative management, palliative operation, and hepatic resection. Conservative management was used for 15 patients, and hepatic resections were performed in 39 patients. The remaining 23 patients had laparotomy alone (10 patients), bile duct intubation (4 patients), hepatic artery ligation (3 patients), bilienteric bypass (3 patients), gastrojejunostomy (1 patient), insertion of a hepatic artery port for regional chemotherapy (1 patient), or open drainage of an abscess (1 patient). The median survival after conservative management, palliative operation, and hepatic resection were 1.8, 2.9, and, 12.2 months, respectively. After hepatic resection, patients without lymphatic permeation (p < 0.02) or hilar nodal metastases (p < 0.0003) survived significantly longer. We concluded that hepatic resection is indicated for intrahepatic cholangiocarcinoma when it is deemed resectable.
Bile Duct Neoplasms↗