Biomedical subjects

J Y W Lau

Publications and source records attributed to J Y W Lau.

7 recordsLinked to original sources

PubMed2005

Developing an animal model of massive ulcer bleeding for assessing endoscopic hemostatic devices.

BACKGROUND: Existing animal models of ulcerative bleeding are not suitable for endoscopic investigation. We describe a new porcine model of massive arterial bleeding in the stomach and its use for assessing a novel endoscopic suturing device. METHODS: Two animal models were investigated. In model 1, the short gastric artery (mean diameter 2 mm) was divided near its gastric end. A mucosal defect was created near the greater curve and the divided artery was brought into the lumen of the stomach through a submucosal tunnel. An inflatable plastic cuff was placed around the base of the artery. Cuff deflation led to massive bleeding. In model 2, the short gastric artery was carefully exposed along a segment of 2 cm on the side facing the stomach. It was then anchored to a small gastrostomy made at the posterior wall near the vessel. At endoscopy an ulcer-like lesion could be seen with a pulsatile vessel at the base and brisk bleeding could be started by cutting a hole in the artery using endoscissors. The pigs were heparinized by an intravenous bolus of 110-300 units per kilogram, in both models. A prototype suturing device, the Eagle Claw, was inserted using a gastroscope and the curved needle was driven around the bleeding artery. Extracorporeal knotting or intracorporeal ligation was done endoscopically. RESULTS: Pulsatile arterial bleeding was successfully created in four pigs using model 1, and in another four pigs using model 2. Model 2 was more reproducible and less time-consuming to create. Endoscopic suturing controlled arterial bleeding in five out of eight pigs with a single stitch and in another three pigs with an additional stitch. CONCLUSION: This animal model provides reproducible massive hemorrhage suitable for endoscopic studies. Control of gastric bleeding from large arteries by endoscopic suturing is possible.

Animals↗

PubMed2004

Imaging for primary hyperparathyroidism--what beginners should know.

For patients with primary hyperparathyroidism surgical removal of the hyperfunctioning parathyroid gland is curative. With advances in minimally invasive surgery, accurate pre-operative localization of the hyperfunctioning parathyroid tissue is essential to aid successful surgical treatment. The onus of identifying this hyperfunctioning parathyroid tissue therefore falls on imaging techniques such as high-resolution ultrasound, radionuclide imaging, computed tomography and magnetic resonance imaging. This article is not an exhaustive review, and its main aim is to familiarize the general radiologist, trainee radiologists and clinicians with the basics of various imaging techniques and their roles in practical management of patients with primary hyperparathyroidism.

Diagnostic Imaging↗

PubMed2004

Factors predicting progression of gastric intestinal metaplasia: results of a randomised trial on Helicobacter pylori eradication.

BACKGROUND AND AIMS: Gastric intestinal metaplasia (IM) is generally considered to be a precancerous lesion in the gastric carcinogenesis cascade. This study identified the risk factors associated with progression of IM in a randomised control study. SUBJECTS AND METHODS: A total of 587 Helicobacter pylori infected subjects were randomised to receive a one week course of anti-Helicobacter therapy (omeprazole, amoxicillin, and clarithromycin (OAC)) or placebo. Subjects underwent endoscopy with biopsy at baseline and at five years. Severity of IM was graded according to the updated Sydney classification and progression was defined as worsening of IM scores at five years in either the antrum or corpus, or development of neoplasia. Backward stepwise multiple logistic regression was used to identify independent risk factors associated with IM progression. RESULTS: Of 435 subjects (220 in the OAC and 215 in the placebo group) available for analysis, 10 developed gastric cancer and three had dysplasia. Overall progression of IM was noted in 52.9% of subjects. Univariate analysis showed that persistent H pylori infection, age >45 years, male subjects, alcohol use, and drinking water from a well were significantly associated with IM progression. Duodenal ulcer and OAC treatment were associated with a reduced risk of histological progression. Progression of IM was more frequent in those with more extensive and more severe IM at baseline. With multiple logistic regression, duodenal ulcer (odds ratio (OR) 0.23 (95% confidence interval (CI) 0.09-0.58)) was found to be an independent protective factor against IM progression. Conversely, persistent H pylori infection (OR 2.13 (95% CI 1.41-3.24)), age >45 years (OR 1.92 (95% CI 1.18-3.11)), alcohol use (OR 1.67 (95% CI 1.07-2.62)), and drinking water from a well (OR 1.74 (95% CI 1.13-2.67)) were independent risk factors associated with IM progression. CONCLUSION: Eradication of H pylori is protective against progression of premalignant gastric lesions.

Aged↗

PubMed2003

Through-the-scope stent for malignant gastric outlet obstruction.

This report is of the technique and results for through-the-scope stent in palliating malignant gastric outlet obstruction for 17 patients. All procedures were done using conscious sedation and fluoroscopy. Enteral Wallstents with a diameter of 20 mm or 22 mm and length 60 mm or 90 mm were used and delivered over a guidewire through an endoscope with an operating channel of at least 3.7 mm. A total of 18 stents were placed. One stent failed to be deployed. One stent migrated and required insertion of a second stent. One patient required repeat endoscopy to stop bleeding from the tumour. Through-the-scope stent relieved obstructive symptoms for 14 (82%) patients. The median dysphagia score improved from 4 to 2 after through-the-scope stent (P=0.001). The median overall survival and hospital-free survival time was 6 weeks (interquartile range, 3-9 weeks) and 4 weeks (interquartile range, 1-7 weeks), respectively. To conclude, through-the-scope stent was safe and feasible, offering an alternative minimal invasive method to palliate obstructive symptoms for patients with inoperable tumours causing gastric outlet obstruction.

Aged↗

PubMed2003

Early extubation after transthoracic oesophagectomy.

OBJECTIVES: To assess patient outcome following transthoracic (Ivor-Lewis) oesophagectomy and the effects of epidural analgesia and early extubation compared with overnight sedation and ventilation. DESIGN: Retrospective study. SETTING: University teaching hospital, Hong Kong. SUBJECTS AND METHODS: A retrospective review of patients undergoing oesophagectomy during two periods, 1990 to 1994 (n=65) and 1995 to 1998 (n=83), was completed. In the latter period, factors associated with early extubation were also evaluated. RESULTS: Between 1990 and 1994, only three (4.6%) of 65 patients were extubated early compared with 34 (41.0%) of 83 patients between 1995 and 1998 (P<0.001). Comparing these two periods, there were no differences in respiratory complications or hospital mortality. In the period 1995 to 1998, more patients who were extubated early had received epidural analgesia (85% versus 41%, P<0.001). There were no differences between the early and late extubation groups in terms of respiratory complications and hospital mortality. Patients extubated early had shorter stays in the intensive care unit (1 versus 2 days, P=0.005). Epidural analgesia was an independent factor associated with early extubation (odds ratio=9.4; 95% confidence interval, 2.8-31.2). CONCLUSION: After transthoracic oesophagectomy, early extubation is safe and can lead to a shorter stay in the intensive care unit. Epidural analgesia appears to facilitate early extubation.

Analgesia, Epidural↗

PubMed2002

The clinical efficacy of neoadjuvant chemotherapy in squamous esophageal cancer: a prospective nonrandomized study of pulse and continuous-infusion regimens with Cisplatin and 5-Fluorouracil.

BACKGROUND: We evaluated cisplatin and 5-fluorouracil as preoperative adjuvant chemotherapy for patients with locally advanced squamous esophageal cancer and compared two different infusion regimens. The outcomes were also compared with those of our historical control patients treated by surgery alone. METHODS: From 1991 to 1997, 83 consecutive esophageal cancer patients underwent surgical exploration after completion of two cycles of cisplatin and 5-fluorouracil chemotherapy regimens, either in pulse or in continuous infusion cycles. Outcomes were compared with those of 76 historical control patients. Both groups were comparable in demographic characteristics and tumor stages. The resection rates, operative morbidity, mortality, and survival rates were compared. RESULTS: Partial response was achieved in 50% of patients who received chemotherapy. There was no chemotherapy-related mortality. The resection, morbidity, and mortality rates and median survival between the surgery-alone group and the chemotherapy group were 71.1% vs. 82%, 51% vs. 55%, and 4% vs. 10.8%, 12.0 vs. 13.5 months, respectively (P >.05). There was also no statistically significant difference between the two regimens. CONCLUSIONS: Preoperative adjuvant chemotherapy with cisplatin and 5-fluorouracil infusion, in pulse or continuous regimens, followed by surgery for squamous esophageal cancer patients had no added benefit in the overall survival.

Adult↗

PubMed2002

Prediction of therapeutic failure after adrenaline injection plus heater probe treatment in patients with bleeding peptic ulcer.

BACKGROUND: Continued or recurrent bleeding after endoscopic treatment for bleeding ulcer is a major adverse prognostic factor. Identification of such ulcers may allow for alternate treatments. AIM: To determine factors predicting treatment failure with combined adrenaline injection and heater probe thermocoagulation. METHODS: Consecutive patients with bleeding peptic ulcers who received endoscopic therapy between January 1995 and March 1998 were studied. Data on clinical presentation, endoscopic findings, and treatment outcomes were collected prospectively. Multiple logistic regression analysis was used to identify independent risk factors for treatment failure. RESULTS: During the study period, 3386 patients were admitted with bleeding peptic ulcers: 1144 (796 men, 348 women) with a mean age of 62.5 (SD 17.6) years required endoscopic treatment. There were 666 duodenal ulcers (58.2%), 425 gastric ulcers (37.2%), and 53 anastomotic ulcers (4.6%). Initial haemostasis was successful in 1128 patients (98.6%). Among them, 94 (8.2%) rebled in a median time of 48 hours (range 3-480). Overall failure rate was 9.6%. Mortality rate was 5% (57/1144). Multiple logistic regression analysis revealed that hypotension (odds ratio (OR) 2.21, 95% confidence interval (CI) 1.40-3.48), haemoglobin level less that 10 g/dl (OR 1.87, 95% CI 1.18-2.96), fresh blood in the stomach (OR 2.15, 95% CI 1.40-3.31), ulcer with active bleeding (OR 1.65, 95% CI 1.07-2.56), and large ulcers (OR 1.80, 95% CI 1.15-2.83) were independent factors predicting rebleeding. CONCLUSIONS: Larger ulcers with severe bleeding at presentation predict failure of endoscopic therapy.

Adult↗