Ann Acad Med Singap
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Ann Acad Med Singap · May 1999
Review1998 Distinguished Academician Lecture: hepatic resection--a Western perspective.
During the past two decades, resection of the liver has progressed from a rarely to a commonly performed operation with a low morbidity and mortality. The description of the functional anatomy of the liver was instrumental in the change from non-anatomic to anatomic resections. Major hepatectomies dominated the early experience but segment orientated resections now play a more prominent role. ⋯ The development of innovative graft reduction techniques has made a major contribution to liver transplantation. The lack of suitable whole liver grafts for paediatric recipients was addressed by volume of reduction of adult donor livers so that the left lateral segment could be implanted safely in an infant's abdomen. This technique was the forerunner of split-liver transplantation, auxiliary partial orthotopic transplantation and living-related liver transplantation.
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In the past, the discovery of new drugs often occurred by chance. Over recent years, an increasing knowledge of the mode of drug action and receptor sites has improved our ability to design new drugs. While the mode of action of volatile and intravenous anaesthetic agents remains unclear, neuromuscular blocking agents and opioids have undergone considerable development and design. ⋯ As a result, the introduction of new drugs has helped to improve techniques in anaesthesia. The development of remifentanil is an example of this which is discussed. The application of modern technology with target controlled infusions (TCI) for the administration of remifentanil represents further advancement in techniques which may become available to anaesthetists in the future.
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Ann Acad Med Singap · May 1999
Review1998 Runme Shaw Memorial Lecture: somatic evolution of cancer.
The interpretation of cancer as a somatic evolutionary process involving genetic mutation followed by selection, traces its origins to the early years this century. The dramatic developments in molecular genetics have substantiated these early ideas. Through the application of positional cloning and genomic analysis, many mutations in particular genes, both dominant oncogenes and tumour suppressor genes have now been found in a wide variety of tumours. ⋯ Simple models for the evolution of a cancer that take into account these two processes, show that cancers evolve initially by a series of finite increases in cell population size, following which there may be long periods of cell turnover during which there is an opportunity for further mutation and selection. This explains the long lag periods between the initiation and subsequent progression of most cancers. Our rapidly developing understanding of cancers at the fundamental genetic level provides new opportunities for developing targeted treatments, as well as novel approaches to prevention and early detection.
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Ann Acad Med Singap · May 1999
Review8th Seah Cheng Siang Memorial Lecture: new antithrombotic agents.
For the long-term prevention of thromboembolic events in patients with atherosclerotic vascular disease, aspirin is the preferred antiplatelet drug. Only clopidogrel was shown to be more effective and at least as safe than medium-dose aspirin in direct comparative large-scale trials. Aspirin inhibits the cyclooxygenase dependent pathway of platelet aggregation while ticlopidine and clopidogrel selectively bind to adenosine diphosphate (ADP) receptors on the platelet surface. ⋯ In aggregate, this class of platelet inhibitors, combined with aspirin and heparin, was shown to reduce ischaemic events in patients with high- and low-risk coronary intervention, stents, unstable angina and non-Q-wave infarction with long-term preservation of the initial benefit. With synthetic GPIIb/IIIa inhibitors there is no suppression of clinical evident restenosis 6 months after the end of treatment. With the doses presently used, bleeding occurs more often with the synthetic GPIIb/IIIa inhibitors (used for 3 days) than with abciximab (used for 12 hours) but there are no direct comparisons between these drugs.
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Ann Acad Med Singap · Mar 1999
Randomized Controlled Trial Comparative Study Clinical TrialA study to assess the effect of dietary supplementation with soluble fibre (Minolest) on lipid levels in normal subjects with hypercholesterolaemia.
Hypercholesterolaemia is one of the major risk factors in the development of coronary artery disease. In recent years, many nonprescription treatments have become available for cholesterol lowering. Minolest is a product that contains guar gum and psyllium as the principal active ingredients. ⋯ The percentage fall in LDL cholesterol increased to 7.16% and 7.37% in subjects who consumed at least 50% and 70% of the treatment respectively. There were few side effects. The authors conclude that this product has a small impact on the lipid profile and may be useful only in subjects with mild hypercholesterolaemia and a low risk of coronary artery disease.