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Biomedical subjects

C K Leow

Publications and source records attributed to C K Leow.

54 records · Page 3Linked to original sources
PubMed1996

Malignant anal tumours in the Chinese population in Hong Kong.

Malignant anal tumours are rare cancers but are particularly common in Switzerland, Poland and Brazil. Very little is known about this condition in the Chinese population. A retrospective study, covering an 11-year period, was performed. A total of 18 patients were treated at the Prince of Wales Hospital, Hong Kong. There were eight squamous cell carcinomas, seven adenocarcinomas and one each of adenosquamous carcinoma, malignant melanoma and leiomyosarcoma. Bleeding per rectum, with or without perianal pain, was the main presenting symptom. Abdominoperineal resection was the treatment modality used in most cases. Adenocarcinomas, seen mainly in males, accounted for about 39% of cases, a figure much higher than that published elsewhere. Another 44% of patients, predominantly females, had squamous cell carcinoma. None had a positive past history of sexually transmitted disease. The local prevalence of HPV infection is much lower than in the Western world, and the role of HPV in the oncogenesis of anal tumours in the Chinese population awaits elucidation.

Adenocarcinoma↗
PubMed1996

Internet and surgery.

In medicine, the Internet is already playing a significant role in the delivery of information on medical conditions, medical and academic institutions and non-profit-making support groups for patients. This article explores some of the available information on the Internet relevant to surgery and discusses its role in surgical training.

Computer Communication Networks↗
PubMed1995

The long-term metabolic function of intraportal and renal subcapsular islet isografts and the effect on glomerular basement membrane thickness in rats.

Previous studies of intraportal islet autotransplantation in large animals have reported graft failure after months or years. In the rat it has been reported that intraportal islet isografts eventually failed whilst islets transplanted to the renal subcapsule functioned up to a year. We made Dark Agouti (DA) rats severely diabetic with streptozotocin, then 1000 or 3000 DA islets were transplanted beneath the renal capsule or into the liver. One set of transplanted rats and untreated diabetic and normal non-diabetic littermates were monitored lifelong by measurement of plasma glucose, others were killed at 6, 12 and 18 months for measurement of haemoglobin A1c, intravenous glucose tolerance test, pancreas insulin content and histology of the kidney. Renal glomerular basement membrane thickness was measured by the orthogonal intercept method. The results showed that intraportal isografts reversed hyperglycaemia significantly faster than renal subcapsular isografts. In the renal subcapsular site, consistent reversal of diabetes was achieved with 3000 islets but not with 1000 islets. Furthermore, intraportal islet grafts with 3000 islets led to lower, normal random glucose level than renal subcapsular grafts for the first 13 months. Normoglycaemia was maintained lifelong in all rats that achieved early normoglycaemia after transplantation of 3000 islets, irrespective of the site of islet transplantation. The fasting glucose, haemoglobin A1c levels, K value and glomerular basement membrane thickness of the recipients of 3000 islets to either the intraportal and subcapsular site were not significantly different from each other and the normal controls up to 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

A comparison of four solutions for cold storage of pancreatic islets.

Clinical pancreatic islet transplantation requires cold storage of islets for some hours. The best solution for cold storage will be that which maintains islet viability for the longest time. We have examined the viability of rat and human islet after storage at 4 degrees C for up to 6 days in Hanks' balanced salt solution, University of Wisconsin solution (UW), and 2 modified versions of this last solution, Sumimoto D (SD) and histidine-lactobionate (HL). The integrity of cold-stored rat and human islets of Langerhans has been examined using supravital stains and electron microscopy. In addition, the viability of cold-stored rat islets was tested by intraportal transplantation into syngeneic streptozotocin-induced diabetic recipients. The in vitro studies showed good preservation of islets stored in UW, SD, and HL for up to 72 hr. In comparison, storage for periods as short as 24 hr in HBSS markedly reduced islet integrity. The transplantation studies showed that rat islets cold stored in HBSS solution for 24 hr were not able to reverse experimental diabetes, whereas those stored in the other 3 solutions for 24 hr successfully reversed diabetes within 1 week of transplantation. After 48-hr cold storage, only islets preserved in HL solution were uniformly capable of producing functioning islet grafts. None of the tested solutions was able to maintain islet viability sufficiently to allow successful transplantation after more than 48 hr of cold storage. These experiments demonstrate that good islet viability is maintained for up to 24 hr of storage in UW, SD, and HL, and even after 48-hr cold storage in HL solution, whereas preservation in HBSS solution was deleterious to islet viability within 24 hr.

Adenosine↗
PubMed1993

Routine use of arteriovenous fistula construction to dilate the venous outflow prior to insertion of an expanded polytetrafluoroethylene (PTFE) loop graft for dialysis.

For long-term haemodialysis to be successful an adequate length of vessel with correspondingly high flow is necessary, and the use of a peripheral arteriovenous fistula (AVF) between brachial artery and median cephalic vein is well described for long-term vascular access. However, the length of vessel available is often insufficient for dialysis and the time-lag between formation and availability for use may be prolonged. Primary insertion of a PTFE interposition graft is an alternative but may be technically difficult due to the small diameter of vein available for run-off, resulting in a significant rate of thrombosis. We advocate early AVF formation in most patients, even where the fistula is unlikely to prove usable for dialysis, with the express purpose of dilating the veins prior to PTFE graft insertion. The time-lag between AVF formation and PTFE graft insertion may be as short as 1 week. Although conversion of a functioning AVF to PTFE interposition graft has been described by others, we believe the routine use of AVF formation prior to PTFE insertion has not been previously advocated and gives a considerable advantage in patients with difficult dialysis access.

Arteriovenous Shunt, Surgical↗
PubMed1986

Endoscopic papillotomy without cholecystectomy for bile duct stones.

Endoscopic papillotomy without cholecystectomy has been performed in 20 elderly patients with complications of bile duct stones. Good biliary drainage was achieved in 17, and there were no complications. One cholecystectomy was subsequently required. Later deaths have been due to unrelated causes. It is concluded that endoscopic treatment alone may be all that is required to manage bile duct stones in the elderly.

Aged↗
PubMedDate not supplied

Successful reversal of diabetes by single donor isologous islet transplantation in a mouse model.

A method for isolating mouse islets which consistently gives a high yield with good purity is described. Using a bovine serum albumin gradient, the mean yield of islets per pancreas is 425 (SEM +/- 15) with a consistent purity of over 90%. Single donor to single recipient of islets transplanted under the renal capsule restores normoglycemia in the diabetic recipients within 2 to 5 days of transplantation.

Animals↗
PubMedDate not supplied

Hepatocellular carcinoma.

Hepatocellular carcinoma is the most common cancer in males. Surgery is the only curative treatment, but is applicable in only 10-15% of patients. Systemic chemotherapy, transarterial embolization or chemo-embolization can only palliate. In the future, selective internal radiation may have a role in downstaging inoperable hepatoma to operable tumour.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

The lateral thyroid ligament of Berry.

Division of the lateral thyroid ligament is essential for total thyroid lobectomy. The exact extent of this ligament, first described by Berry in 1888, was studied in a series of 25 cadaveric and post-mortem subjects. The ligament was attached to the inferior margin of the cornu of the cricoid cartilage, near its pole, and extended infero-medially onto the tracheal wall, reaching the midline in 4 of the 50 lobes examined. At the level of the cricoid cartilage, the mean distance between the attachment of the ligament to the cricoid cartilage and the recurrent laryngeal nerve (RLN) entry point into the larynx was 1.9 mm. This region corresponds to the area where RLNs are mostly injured during thyroid surgery. Awareness of the extent of this ligament and the proximity of the RLN to it should lessen the risk of injury to the RLN during thyroid lobectomy and total thyroidectomy.

Cadaver↗