A factorization-based projective reconstruction algorithm with circular motion constraint

In this paper, we propose a projective reconstruction algorithm for a circular motion image sequence. We first formulate the circular motion constraint in the Euclidean frame, and then deduce its expression in a projective frame. The circular motion constraint is gradually enforced during the iterations of a projective reconstruction. This approach can be used to deal with both constant and varying intrinsic parameters. Experimental results for synthetic and real data are presented to illustrate the performance and improvements of our approach over methods based on general motion. ©2004 IEEE.published_or_final_versio

Percutaneous transluminal angioplasty for stenosis of arteriovenous fistulae: a review of local experience

The stenosis and subsequent thrombosis of the arteriovenous fistula may lead to a loss of vascular access sites; this a major problem in chronic haemodialysis patients. Percutaneous transluminal angioplasty has been a popular way of correcting such lesions in recent years. We have reviewed patients who underwent this operation from 1993 to 1996 at the Queen Mary Hospital. Among 11 patients who were documented as having arteriovenous fistula stenosis, 60% of lesions were in the anastomotic area while 40% were in the venous limb. All patients had abnormal dialysis blood line pressures corresponding to the actual site of stenosis. The initial success rate of percutaneous transluminal angioplasty in treating the stenotic lesions was 73%. This method is thus a promising form of semi-invasive treatment for symptomatic arteriovenous fistula stenosis.published_or_final_versio

A survey of chronic rhinitis in Hong Kong

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Surveillance colonoscopy in patients with serrated lesions at baseline

Poster Session: Other Lower GI Disorders 3: Lower GI malignant disease, pathogenesis: Paper no. 1655published_or_final_versio

Diffusion of aromatic compounds in nonaqueous solvents : a study of solute, solvent, and temperature dependences

Author name used in this publication: Chan, T. C.Author name used in this publication: Tang, W. K.2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

香港977位慢性鼻炎患者的過敏原皮膚點刺測試結果

OBJECTIVES: To evaluate the prevalence of aetiological allergens identifiable by skin prick test alone in patients suffering from chronic rhinitis in Hong Kong, and also compare the clinical history and symptoms of skin prick test-positive versus skin prick test-negative patients. DESIGN: Prospective study. SETTING: Otorhinolaryngology clinic in Queen Mary Hospital of Hong Kong. PATIENTS: A total of 977 patients suffering from chronic rhinitis were recruited into the study. Skin prick test was performed with a panel of allergens including house dust mites, cockroach, cat, dog, moulds, and pollens. MAIN OUTCOME MEASURES: Skin prick test results and their correlation with symptoms. RESULTS: Of the 977 patients, 651 (67%) had positive skin prick test reactions. The commonest allergen was house dust mite which was positive in 63% of the 977 patients and 95% of those 651 skin prick test-positive patients. The other allergens were in order of cockroach (23%), cat (14%), dog (5%), pollen (4%), and mould (3%). Compared with skin prick test-negative patients, skin prick test-positive patients were more likely to have earlier age of onset of the chronic rhinitis, association with asthma, more severe symptom in the morning, more severe symptoms of itchy nose, sneezing, nasal discharge, itchy eye, and watery eye. CONCLUSIONS: Identifiable aeroallergens could be detected in 67% chronic rhinitis patients by skin prick test alone. House dust mites were the most prevalent causative allergen. There were significant differences of patterns of clinical history and symptoms severity between skin prick test-positive and skin prick test-negative patients.published_or_final_versio

Intravenous bolus somatostatin after diagnostic cholangiopancreatography reduces the incidence of pancreatitis associated with therapeutic endoscopic retrograde cholangiopancreatography procedures: A randomised controlled trial

Background: Previous studies suggested that somatostatin given before endoscopic retrograde cholangiopancreatography (ERCP) may reduce the incidence of post-ERCP pancreatitis. However, the routine use of somatostatin in all patients undergoing ERCP is not likely to be cost effective. This study evaluated whether intravenous bolus somatostatin given after diagnostic cholangiopancreatography could reduce the incidence of pancreatitis in a group of patients undergoing therapeutic ERCP procedures. Methods: In a randomised, double blind, controlled trial, the effect of intravenous bolus somatostatin 250 μg given immediately after diagnostic cholangiopancreatography was compared with that of placebo in patients who required endoscopic sphincterotomy or other therapeutic procedures. The primary end point was the incidence of post-ERCP clinical pancreatitis, and a secondary end point was the incidence of hyperamylasemia. Results: A total of 270 patients were randomised. The somatostatin group (n = 135) and the placebo group (n = 135) were comparable in age, sex, indications for treatment, and types of procedure. The frequencies of clinical pancreatitis (4.4% v 13.3%; p = 0.010) and hyperamylasemia (26.0% v 38.5%; p = 0.036) were both significantly lower in the somatostatin group compared with the placebo group. Conclusions: A single dose of intravenous bolus somatostatin, given immediately after diagnostic cholangiopancreatography, is effective in reducing the incidence of pancreatitis after therapeutic ERCP. This novel approach of administering prophylactic somatostatin may offer a cost effective prophylaxis for post-ERCP pancreatitis.published_or_final_versio

Rapid aneuploidy testing (knowing less) versus traditional karyotyping (knowing more) for advanced maternal age: What would be missed, who should decide?

Objectives The application of rapid aneuploidy testing as a stand-alone approach in prenatal diagnosis is much debated. The major criticism of this targeted approach is that it will not detect other chromosomal abnormalities that will be picked up by traditional karyotyping. This study aimed to study the nature of such chromosomal abnormalities and whether parents would choose to terminate affected pregnancies. Design Retrospective study on a cytogenetic database. Setting Eight public hospitals in Hong Kong. Participants The karyotype results of 19 517 amniotic fluid cultures performed for advanced maternal age (≥35 years) from 1997 to 2002 were classified according to whether they were detectable by rapid aneuploidy testing. The outcomes of pregnancies with abnormal karyotypes were reviewed from patient records. Results In all, 333 (1.7%) amniotic fluid cultures yielded abnormal karyotypes; 175 (52.6%) of these were detected by rapid aneuploidy testing, and included trisomy 21 (n=94, 28.2%), trisomy 18 or 13 (n=21, 6.3%), and sex chromosome abnormalities (n=60, 18.0%). The other 158 (47.4%) chromosomal abnormalities were not detectable by rapid aneuploidy testing, of which 63 (18.9%) were regarded to be of potential clinical significance and 95 (28.5%) of no clinical significance. Pregnancy outcomes in 327/333 (98.2%) of these patients were retrieved. In total, 143 (42.9%) of these pregnancies were terminated: 93/94 (98.9%) for trisomy 21, 20/21 (95.2%) for trisomy 18 or 13, 19/60 (31.7%) for sex chromosome abnormalities, and 11/63 (17.5%) for other chromosomal abnormalities with potential clinical significance. There were no terminations in the 95 pregnancies in which karyotyping results were regarded to be of no clinical significance. Conclusions 'Knowing less' by the rapid aneuploidy stand-alone testing could miss about half of all chromosomal abnormalities detectable by amniocentesis performed for advanced maternal age. Findings from two fifths of the latter were of potential clinical significance, and the parents chose to terminate one out of six of the corresponding pregnancies. If both techniques are available, parents could have enhanced autonomy to choose.published_or_final_versio

Effects of mandibular setback with or without maxillary advancement osteotomies on pharyngeal airways: An overview of systematic reviews

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Different cell kinetic changes in rat stomach cancer after treatment with celecoxib or indomethacin: Implications on chemoprevention

Aim: Mechanisms underlying the chemopreventive effects of cyclooxygenase (COX) inhibitors remain elusive. We have previously shown that celecoxib but not indomethacin could prevent carcinogen-induced gastric cancer development in Wistar rats. This chemopreventive effect appeared to be independent of COX-2 and prostaglandin (PG) E2 suppression since the lowest PGE2 was obtained in indomethacin group. This study compared the cell kinetic changes in stomachs of rats after treatment with celecoxib (5, 10, 20 mg/(kg·d)) or indomethacin (3 mg/(kg·d)) to gain more insights into the chemopreventive mechanism. Methods: The apoptosis and proliferation indexes in gastric tumor, adjacent non-cancer tissues and normal gastric tissues were determined. Apoptosis was quantified by apoptotic nuclei counting and TUNEL, whereas proliferation was determined by Ki67 immunostaining. Results: Treatment with either celecoxib or indomethacin inhibited gastric tumor proliferation by more than 65% (P<0.02). However, celecoxib caused a dose-dependent increase in apoptosis (P<0.05) which was not seen in indomethacin-treated tumors (P = 0.54). The highest apoptosis to proliferation ratio was seen in tumors treated with celecoxib at 10 mg/(kg·d). Treatment with this dose of celecoxib was associated with the lowest incidence of gastric cancer development. Conclusion: Our findings suggest that the difference in chemopreventive effects of indomethacin and celecoxib in this animal model of gastric carcinogenesis is largely due to the differential cell kinetic changes, which does not correlate with the degree of COX-2 and PG suppression. © 2005 The WJG Press and Elsevier Inc. All rights reserved.published_or_final_versio