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Biomedical subjects

K J Ng

Publications and source records attributed to K J Ng.

At least 19 recordsLinked to original sources
PubMed2003

POSSUM--a model for surgical outcome audit in quality care.

Comparative surgical audit to monitor quality of care should be performed with a risk-adjusted scoring system rather than using crude morbidity and mortality rates. A validated and widely applied risk adjusted scoring system, P-POSSUM (Portsmouth-Physiological and Operative Severity Score for the enUmeration of Mortality) methodology, was applied to a prospective series of predominantly general surgical patients at the Sarawak General Hospital, Kuching over a six months period. The patients were grouped into four risk groups. The observed mortality rates were not significantly different from predicted rates, showing that the quality of surgical care was at par with typical western series. The simplicity and advantages of this scoring system over other auditing tools are discussed. The P-POSSUM methodology could form the basis of local comparative surgical audit for assessment and maintenance of quality care.

Adult↗
PubMed2002

Risk-adjusted surgical audit with the POSSUM scoring system in a developing country. Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity.

BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) is an objective and appropriate scoring system for risk-adjusted comparative general surgical audit. This score was devised in the UK and has been used widely, but application of POSSUM to centres outside the UK has been limited, especially in developing countries. This prospective study validated its application in a surgical practice with a different population and level of resources. METHODS: All general surgical patients who were operated on under regional or general anaesthesia as inpatients over a 4-month period at Sarawak General Hospital in 1999 were entered into the study. All data (12 physiological and six operative factors) were analysed for mortality only with the POSSUM equation and the modified Portsmouth POSSUM (P-POSSUM) equation. Comparisons were made between predicted and observed mortality rates according to four groups of risk: 0-4, 5-14, 15-49 and 50 per cent or more using the 'linear' method of analysis. RESULTS: There were 605 patients who satisfied the criteria for the study. Some 56.7 per cent of patients were in the lowest risk group. The POSSUM predictor equation significantly overestimated the mortality in this group, by a factor of 9.3. The overall observed mortality rate was 6.1 per cent and, again, the POSSUM predictor equation overestimated it at 10.5 per cent (P < 0.01). In contrast, the observed and predicted mortality rates for all risk groups, including the predicted overall mortality rate of 4.8 per cent, were comparable when the P-POSSUM predictor equation was used. CONCLUSION: The POSSUM scoring system with the modified P-POSSUM predictor equation for mortality was applicable in Malaysia, a developing country, for risk-adjusted surgical audit. This scoring system may serve as a useful comparative audit tool for surgical practice in many geographical locations.

Adolescent↗
PubMed2001

Cassette-accelerated rapid rat screen: a systematic procedure for the dosing and liquid chromatography/atmospheric pressure ionization tandem mass spectrometric analysis of new chemical entities as part of new drug discovery.

This report addresses the continuing need for increased throughput in the evaluation of new chemical entities (NCEs) in terms of their pharmacokinetic (PK) parameters by describing an alternative procedure for increasing the throughput of the in vivo screening of NCEs in the oral rat PK model. The new approach is called "cassette-accelerated rapid rat screen" (CARRS). In this assay, NCEs are dosed individually (n = 2 rats/compound) in batches of six compounds per set. The assay makes use of a semi-automated protein precipitation procedure for sample preparation in a 96-well plate format. The liquid chromatography/atmospheric pressure ionization tandem mass spectrometry (LC/API-MS/MS) assay is also streamlined by analyzing the samples as "cassettes of six". Using this new approach, a threefold increase in throughput was achieved over the previously reported "rapid rat screen".

Administration, Oral↗
PubMed1994

Three-dimensional imaging of the prostatic urethra--an exciting new tool.

OBJECTIVE: To evaluate the technique of three-dimensional (3-D) ultrasound imaging of the urethra and its application in both research and clinical practice. PATIENTS AND TECHNIQUE: The study involved 23 patients: 10 with benign prostatic hyperplasia, four with urethral strictures, three post-insertion of prostatic stents, one with bladder neck dyssynergia, three post-transurethral resection of the prostate, and two with non-urological conditions. A transrectal ultrasound scan was initially performed to acquire a series of images of the urethra. These images were then reconstructed into a 3-D format. RESULTS: The 3-D image of the urethra could be rotated on screen and viewed from any angle. The image could also be sliced at any plane to reveal the sectional view. CONCLUSION: This new tool represents a major advance in imaging techniques and promises to provide new knowledge in understanding the hydrodynamics of the lower urinary tract. The precise geometry of the 3-D urethra will also help in the design of new stents.

Humans↗
PubMed1994

Intralobar bronchopulmonary sequestration: antenatal diagnosis.

A child with the antenatal diagnosis of pulmonary cystic adenomatoid malformation underwent thoracotomy and an intralobar bronchopulmonary sequestration was found. Histological examination of the resected specimen showed cystic adenomatoid malformation within the sequestered segment.

Child, Preschool↗
PubMed1992

Endoscopic transanal resection of large villous tumours of the rectum.

Endoscopic transanal resection (ETAR) is an innovative approach in the management of low lying tumours of the rectum. We report our experience of this technique in six elderly patients (mean age 74 years) with large villous adenomas, situated between 2 and 12 cm from the anal verge. There were no complications. One patient with a circumferential tumour has been spared the more conventional operation of abdominoperineal excision. Follow-up ranged from 6 to 30 months (mean 16 months) during which two recurrences were detected. These were adequately treated by further ETARs. It is concluded that ETAR is a simple and well-tolerated procedure and is a useful addition to the surgeon's armamentarium.

Adenoma↗
PubMed1991

Experience with the APACHE II severity of disease scoring system in predicting outcome in a surgical intensive therapy unit.

The APACHE II system, a severity of disease scoring system, has been used to identify intensive therapy unit patients in whom prolonged treatment is unlikely to be beneficial. Fifty-nine surgical patients admitted to the intensive care unit over a 6-month period underwent a single APACHE II scoring in the first 24 h. The overall 30-day mortality rate was 34%. The range of APACHE II scores was 3-29. The survivors had significantly lower scores (mean 11) than those who died (mean 19). Most patients (53%) had a score greater than or equal to 11 to less than or equal to 22 and had an equal chance of living or dying. No patient with a score greater than 22 survived and at this level the APACHE II score was highly specific (100%) but with a very low sensitivity (30%). APACHE II scores greater than 22 may be useful as an adjunct to a clinical decision to withhold treatment, but scores below that level lack the specificity and sensitivity to be of any value.

Aged↗
PubMed1986

Modulation of the 5-lipoxygenase activity of MC-9 mast cells: activation by hydroperoxides.

In order to identify regulatory steps in leukotriene synthesis, the biochemical characteristics of a 5-lipoxygenase activity in the 100,000 xg supernatant from sonicates of cells of an IL-3 dependent murine mast cell clone, MC-9 were determined. Principal products from exogenous 14C-arachidonic acid were identified as leukotriene B4, diastereomeric 5,12-dihydroxy-eicosatetraenoic acids (5,12 diHETEs) 5-hydroperoxy and hydroxyeicosatetraenoic acids (5-HPETE and 5-HETE) as well as a novel metabolite 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE). The crude lipoxygenase activity had a pH optimum of 6.9 and was highly dependent upon added Ca++. The effective Ca++ concentration for 50 per cent activation (EC50) was 3 microM. Activity was also stimulated by ATP (EC50 = 160 microM). The cytosolic 5-lipoxygenase activity exhibited a biphasic concentration dependence for arachidonic acid with maximum product formation occurring at 35 microM (ca. 20 nmole/mg/4 min). The lipoxygenase activity exhibited apparent lag phase kinetics which were more pronounced at low protein concentrations (0.3 mg/ml). In addition, the lag phase was greatly accentuated by the addition of a hydroperoxide scavenging system consisting of glutathione (1 mM) plus glutathione peroxidase (0.4 unit/ml). In contrast, addition of any of several hydroperoxides, i.e. 5-,8-,9- or 15-HPETE (EC50 ca. 1 microM), but not the corresponding alcohols (5-HETE and 15-HETE), shortened the lag phase. These results show that the 5-lipoxygenase requires hydroperoxide for activation and that cellular level of hydroperoxides may be an important factor regulating leukotriene synthesis.

Adenosine Triphosphate↗
PubMed1983

Identification of long chain dicarboxylic acids in the serum of two patients with Reye's syndrome.

Sera from two patients with Reye's Syndrome were analysed by computerized capillary gas chromatography--mass spectrometry profiling techniques. The most striking abnormalities were the accumulation of long chain dicarboxylic acids. Four saturated dicarboxylic acids (dodecanedioic, tetradecanedioic, hexadecanedioic, and octadecanedioic), and six unsaturated long chain dicarboxylic acids (dodecenedioic, tetradecenedioic, tetradecadienedioic, hexadecenedioic, octadecadienedioic, and octadecenedioic) were identified. The C16 and C13 dicarboxylic acids have never been reported for Reye's Syndrome or any other dicarboxylic acidemias. The data might reflect marked increase of extramitochondrial omega-oxidation of long chain fatty acids or impaired metabolism of omega-dicarboxylic acids formed in Reye's patients.

Child↗