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Chow CC, Mo KL, Chan CK, Lo HK, Wong KS, Chan JCW. Renal impairment in patients with multiple myeloma. Hong Kong Med J 2003; 9:78-82. [PMID: 12668816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
OBJECTIVES To determine the incidence of multiple myeloma in the Eastern District of Hong Kong Island, the degree of renal impairment at presentation, and its relationship with haematological and biochemical parameters and survival. DESIGN Retrospective study. SUBJECTS AND METHODS Patients with myeloma who were admitted to a regional hospital in Hong Kong from January 1994 to March 2000 were included. Demographic data, type and stage of multiple myeloma, degree of renal impairment, haematological and biochemical parameters, and survival data were analysed. RESULTS There were 64 patients (28 male, 36 female) in the study. The incidence rate for multiple myeloma in this group was 1.78 per 100 000 population. Immunoglobulin G (53.1%) was the most common type of multiple myeloma seen, followed by immunoglobulin A (29.7%), light-chain (12.5%), and immunoglobulin D (4.7%). Nineteen (29.7%) patients had serum creatinine levels of greater than 177 micro mol/L at presentation. Renal impairment was more common in patients with light-chain multiple myeloma (P=0.081). The serum creatinine level was not significantly correlated with haemoglobin level (r= -0.21), platelet count (r=0.04), serum calcium level (r=0.08), or albumin level (r= -0.03). The median survival time for patients with multiple myeloma was 592 days (95% confidence interval, 229-955). Serum creatinine level at presentation was significantly associated with survival (P=0.017). Patients with a creatinine level of less than 400 micromol/L had longer survival (P=0.042). Infection was the most common cause of death (32.8%). CONCLUSION The incidence rate noted was comparable to other published studies. Renal impairment at presentation was common in patients with multiple myeloma and was associated with poor survival.
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Wong WM, Gu Q, Lam SK, Fung FMY, Lai KC, Hu WHC, Yee YK, Chan CK, Xia HHX, Yuen MF, Wong BCY. Randomized controlled study of rabeprazole, levofloxacin and rifabutin triple therapy vs. quadruple therapy as second-line treatment for Helicobacter pylori infection. Aliment Pharmacol Ther 2003; 17:553-60. [PMID: 12622764 DOI: 10.1046/j.1365-2036.2003.01459.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIM To test the efficacy of rabeprazole, levofloxacin and rifabutin triple therapy vs. quadruple therapy for the second-line treatment of Helicobacter pylori infection. METHODS One hundred and nine patients who had failed previous H. pylori eradication were randomized to receive: (i) rabeprazole, 20 mg b.d., rifabutin, 300 mg once daily, and levofloxacin, 500 mg once daily, for 7 days (triple therapy); or (ii) rabeprazole, 20 mg b.d., metronidazole, 400 mg t.d.s., bismuth subcitrate, 120 mg q.d.s., and tetracycline, 500 mg q.d.s., for 7 days (quadruple therapy). Endoscopy and culture were performed before treatment. RESULTS The clarithromycin (79% vs. 21%, P < 0.001) and metronidazole (89% vs. 40%, P < 0.001) resistance rates were significantly higher in patients with previous exposure than in those with no previous exposure. The intention-to-treat and per protocol eradication rates were 91%/91% for the triple therapy group and 91%/92% for the quadruple therapy group. For patients with double resistance to metronidazole and clarithromycin, the eradication rates were 85% (17/20) in the triple therapy group and 87% (13/15) in the quadruple therapy group. Compliance was greater than 95% for both regimens. CONCLUSION Rabeprazole, levofloxacin and rifabutin-based triple therapy and quadruple therapy were equally effective as second-line treatments for H. pylori infection.
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Xia HHX, Lai KC, Lam SK, Hu WHC, Wong NYH, Hui WM, Lau CP, Chen WH, Chan CK, Wong WM, Wong BCY. Symptomatic response to lansoprazole predicts abnormal acid reflux in endoscopy-negative patients with non-cardiac chest pain. Aliment Pharmacol Ther 2003; 17:369-77. [PMID: 12562449 DOI: 10.1046/j.1365-2036.2003.01436.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIM To determine whether symptomatic response to lansoprazole predicts abnormal acid reflux in endoscopy-negative patients with non-cardiac chest pain. METHODS Patients who complained of chest pain, but had normal coronary angiography, were asked to undergo upper endoscopy. Those without gastric and oesophageal lesions were recruited for 24-h ambulatory oesophageal pH monitoring, and were randomly given lansoprazole 30 mg or placebo, both daily for 4 weeks. Chest pain symptoms were recorded before and 1 month after treatment on a locally validated questionnaire. The symptom score was calculated by multiplying the severity and frequency of the symptom, and symptom improvement was defined as > 50% reduction in symptom score. RESULTS Overall, 68 patients, 36 on lansoprazole and 32 on placebo, completed the trial. The symptom score was reduced significantly in both groups (P < 0.001). In the lansoprazole group, more patients with than without abnormal reflux showed symptom improvement (92% vs. 33%; odds ratio = 22; 95% confidence interval, 2.3-201.8; chi2 = 10.9; P = 0.001), giving a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 92%, 67%, 58%, 94% and 75%, respectively. In the placebo group, the rates of symptom improvement were similar between those with and without abnormal reflux (33% vs. 35%, P = N.S.). CONCLUSIONS Treatment with lansoprazole is a useful test in diagnosing endoscopy-negative gastro-oesophageal reflux disease in Chinese patients with non-cardiac chest pain.
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Tung CK, Chan CK. Dynamics of spiral waves under phase feedback control in a Belousov-Zhabotinsky reaction. PHYSICAL REVIEW LETTERS 2002; 89:248302. [PMID: 12484985 DOI: 10.1103/physrevlett.89.248302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2002] [Indexed: 05/24/2023]
Abstract
Feedback control of spiral waves by the phases of the spiral tip is investigated experimentally in a light-sensitive Belousov-Zhabotinsky reaction. The phases of rotation (Psi(r)) and meandering (Psi(m)) of the spiral tip are obtained in real time during experiments. It is found that, for both meandering and rigid rotating spirals, one can manipulate the spirals to move with any arbitrary paths by the feedback signals derived from Psi(r). Synchronization between meandering and rotation dynamics can be induced when both Psi(m) and Psi(r) are used simultaneously as control signals. Experimental findings are compared well with numerical simulations of the Oregonator model.
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Wong WM, Lam SK, Hui WM, Lai KC, Chan CK, Hu WHC, Xia HHX, Hui CK, Yuen MF, Chan AOO, Wong BCY. Long-term prospective follow-up of endoscopic oesophagitis in southern Chinese--prevalence and spectrum of the disease. Aliment Pharmacol Ther 2002; 16:2037-42. [PMID: 12452935 DOI: 10.1046/j.1365-2036.2002.01373.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIMS To study the prevalence, clinical characteristics and long-term outcome of oesophagitis in Chinese patients. METHODS Clinical and endoscopic data were collected prospectively from consecutive patients who underwent upper endoscopy between 1997 and 2001. Patients with endoscopic oesophagitis were graded according to the Los Angeles system and analysed according to their clinical presentation, endoscopic details, Helicobacter pylori status, non-steroidal anti-inflammatory drug history, co-morbidity and mortality. RESULTS A total of 22,628 upper endoscopies were performed in 16,606 patients. Of these, 631 (3.8%) had endoscopic oesophagitis, 14 had benign oesophageal stricture (0.08%) and 10 had Barrett's oesophagus (0.06%). Most patients (94%) had either Los Angeles grade A or grade B oesophagitis. Patients who died during follow-up had a significantly higher incidence of co-morbid illness (100% vs. 63%, P < 0.001). By Cox regression analysis, the presence of gastrointestinal bleeding (P = 0.008), advanced age (P = 0.004) and the use of Ryle's tube (P = 0.043) were identified to be independent factors associated with mortality. CONCLUSIONS Complicated gastro-oesophageal reflux disease is uncommon in the Asian population. Advanced age, use of Ryle's tube and the presence of gastrointestinal bleeding are associated with a poor long-term outcome, which is a reflection of the severe underlying co-morbidity.
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Hung WK, Wong WM, Wong GSW, Yip AWC, Szeto ML, Lai KC, Hu WHC, Chan CK, Xia HHX, Yuen MF, Fung FMY, Tong TSM, Ho VYK, Lam SK, Wong BCY. One-week ranitidine bismuth citrate, amoxicillin and metronidazole triple therapy for the treatment of Helicobacter pylori infection in Chinese. Aliment Pharmacol Ther 2002; 16:2067-72. [PMID: 12452939 DOI: 10.1046/j.1365-2036.2002.01384.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND We have previously shown that ranitidine bismuth citrate-based, clarithromycin-containing triple therapy achieves a higher eradication rate than proton pump inhibitor-based regimens in areas with a high prevalence of metronidazole resistance. AIM To evaluate whether this higher efficacy of ranitidine bismuth citrate over proton pump inhibitor can be extended to non-clarithromycin-containing regimens. METHODS Helicobacter pylori-positive dyspeptic patients were randomized to receive either ranitidine bismuth citrate, 400 mg, amoxicillin, 1000 mg, and metronidazole, 400 mg, or omeprazole, 20 mg, amoxicillin, 1000 mg, and metronidazole, 400 mg, each given twice daily for 1 week. H. pylori eradication was confirmed by 13C-urea breath test 5 weeks later. The side-effects of the treatments were documented. RESULTS Two hundred and twenty-nine patients were eligible for analysis. By intention-to-treat and per protocol analysis, the eradication rates were 77% and 79%, respectively, in the ranitidine bismuth citrate-amoxicillin-metronidazole group and 77% and 82%, respectively, in the omeprazole-amoxicillin-metronidazole group (P = 0.58 and P = 0.65). However, patients in the omeprazole-amoxicillin-metronidazole group reported a significantly higher incidence of minor side-effects when compared to those in the ranitidine bismuth citrate-amoxicillin-metronidazole group (P = 0.001). CONCLUSIONS Ranitidine bismuth citrate-amoxicillin-metronidazole was equally as effective as omeprazole-amoxicillin-metronidazole triple therapy, and may be considered as an alternative non-clarithromycin-based regimen in the Chinese population.
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Marras TK, Szalai JP, Chan CK, Lipton JH, Messner HA, Laupacis A. Pulmonary function abnormalities after allogeneic marrow transplantation: a systematic review and assessment of an existing predictive instrument. Bone Marrow Transplant 2002; 30:599-607. [PMID: 12407435 DOI: 10.1038/sj.bmt.1703700] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2002] [Accepted: 06/26/2002] [Indexed: 11/09/2022]
Abstract
Pulmonary function testing (PFT) is used to characterize non-infectious pulmonary complications after allogeneic BMT. Identifying high-risk patients could facilitate preventive or early therapeutic measures. The objectives of the study were first, to review available data on PFT changes after BMT and second, to validate a previously published predictive index for PFT obstruction in patients transplanted at one center. For the systematic review, frequency, severity and time course of PFT changes after BMT and for the validation study, retrospective cohort comparing predicted with observed PFT, and calculation of indices of predictive accuracy were summarized. The validation study involved 434 patients from Princess Margaret Hospital, Toronto, Canada, who received their first BMT between 1980 and 1997, survived for at least 6 months and had adequate PFT follow-up. The systematic review included 20 studies. After BMT, decreased diffusion and total lung capacity were common and partially reversible. Obstruction was less common. The validation study of a previously published index, performed in 434 patients, found a sensitivity and specificity of 48% and 68% for identifying patients who develop obstruction. We concluded that PFT changes after BMT are common. A published predictive index is not sufficiently accurate to identify high-risk patients for potential preventive or early therapeutic strategies.
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Choi HJ, Lim ST, Lai PY, Chan CK. Turbulent drag reduction and degradation of DNA. PHYSICAL REVIEW LETTERS 2002; 89:088302. [PMID: 12190505 DOI: 10.1103/physrevlett.89.088302] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2001] [Indexed: 05/23/2023]
Abstract
Turbulent drag reduction induced by lambda-DNA is studied. The double-stranded DNA is found to be a good drag reducer when compared with the other normal linear polymers. However, this drag reducing power disappears when the DNA denatures to form two single-strand molecules. Mechanical degradation of DNA is also different from that of the normal linear-chain polymers: DNA is always cut in half by the turbulence. Our results suggest that the mechanism for turbulent degradation of DNA is different from that of the normal flexible long-chain polymers.
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Marras TK, Sanders K, Lipton JH, Messner HA, Conly J, Chan CK. Aerosolized pentamidine prophylaxis for Pneumocystis carinii pneumonia after allogeneic marrow transplantation. Transpl Infect Dis 2002; 4:66-74. [PMID: 12220242 DOI: 10.1034/j.1399-3062.2002.t01-1-00008.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pneumocystis carinii pneumonia (PCP) poses a serious risk to allogeneic bone marrow transplant (BMT) patients, who are often intolerant of trimethoprim-sulfamethoxazole (TMP-SMX), the traditional first-line prophylactic agents. There are limited published data supporting the use of aerosolized pentamidine (AP) prophylaxis in the BMT population. We assessed the effectiveness of AP in BMT recipients by reviewing the experience at our center. We divided our review into four time periods from January 1990 to March 2000, during which approximately 700 BMTs were performed. The first period includes patients receiving AP treatments from January 1990 to July 1997 (baseline), the second from August 1997 to July 1998 (pre-outbreak), the third from August 1998 to October 1999 (outbreak), and the fourth from November 1999 to March 2000 (post-outbreak). At our center, TMP-SMX is the first-line agent for PCP prophylaxis, which is routinely continued for at least one year, or for the duration of enhanced immunosuppression. During the baseline period, 505 BMTs were performed and 192 patients (38%) received AP for part of their time at risk. Six patients (3%) experienced toxicities requiring discontinuation of AP. Three cases of PCP were diagnosed over 1114 patient-months of treatment in the baseline period. During the last 42 months of the baseline period, 2/154 patients receiving AP and 2 of an estimated 293 patients receiving exclusively oral prophylaxis developed breakthrough PCP (p = 0.61). During the outbreak period, 9 of 180 patients receiving AP developed PCP compared to none in the group receiving exclusively oral prophylaxis. Either changes in our AP protocol during the pre-outbreak period or pentamidine resistance may have led to this failure of prophylaxis. There were no further cases during the 5-month post-outbreak period. Our observed overall breakthrough rate was 12 cases out of 439 patients (2.7%). Our study shows that AP is an effective and well-tolerated second-line agent in preventing PCP post BMT and we recommend its continued use in this regard. However, it should be administered using a well-studied protocol, and only when TMP-SMX is not tolerated.
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Hu WHC, Wong NYH, Lai KC, Hui WM, Lam KF, Wong BCY, Xia HHX, Chan CK, Chan AOO, Wong WM, Tsang KWT, Lam SK. Normal 24-hour ambulatory proximal and distal gastroesophageal reflux parameters in Chinese. Hong Kong Med J 2002; 8:168-71. [PMID: 12055360 DOI: pmid/12055360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE To quantify normal proximal and distal oesophageal acid parameters in healthy Chinese. DESIGN Observational study. SETTING University teaching hospital, Hong Kong. SUBJECTS AND METHODS Twenty healthy adults who were not on medication and were free from gastrointestinal symptoms were recruited by advertisement. Ambulatory oesophageal acid (pH<4) exposure parameters were recorded at distal and proximal sites, 5 and 20 cm, respectively above the lower oesophageal sphincter. RESULTS The 95th percentile for reflux parameters assessed in the distal/proximal oesophagus were: percent total time pH<4, 4.6/0.7%; percent upright time pH<4, 7.0/1.1%; percent supine time pH<4, 4.5/0.5%; number of reflux episodes, 73/12; number of reflux episodes with pH<4 for >5 minutes, 4/0; and the longest single acid exposure episode, 11.2/3.0 minutes. CONCLUSION Physiological gastroesophageal reflux occurs in healthy Chinese. These initial data provide a preliminary reference range that could be utilised by laboratories studying Chinese subjects.
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Hung CT, Lau LL, Chan CK, Chow B, Chui PT, Ho B, Kung MC, Lui J, Hui T, Ho E, Chan SF, Chen PP. Acute pain services in Hong Kong: facilities, volume, and quality. Hong Kong Med J 2002; 8:196-201. [PMID: 12055366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Acute pain services in public hospitals in Hong Kong were studied. Audit data on the volume and quality of acute pain services were collected prospectively from 1997 to 1999, and data on related facilities were collected in 2000. About 20% of patients undergoing a major operation received an acute pain service; of these, 78.6% were satisfied with the treatment provided. In 2000, 86% (18/21) of hospitals providing anaesthetic services were running an acute pain service. Staffing was better in hospitals providing a high volume of acute pain services, ranging from a full-time specialist anaesthesiologist assisted by a half-time trainee to a half-time specialist assisted by a full- or half-time trainee. However, only four hospitals were staffed with pain nurses. In total, 57% of patients received intravenous patient-controlled analgesia and 32% epidural analgesia. The mean duration of acute pain service treatment was 3.1 days. Currently anaesthesiologist-based acute pain services take care of a limited number of patients. To expand the coverage, there should be a move towards an anaesthesiologist-led, pain nurse-based, acute pain service. The present shortage of pain nurses should be addressed.
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Marras TK, Chan CK. Antibiotic guidelines for pneumonia in chronic-care facilities. CLIN INVEST MED 2002; 25:63-4; author reply 64. [PMID: 12137250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Wong WM, Wong BCY, Xia HHX, Tang VSY, Lai KC, Hu WHC, Yuen MF, Chan CK, Lam SK. An evaluation of a rapid urine test for the diagnosis of Helicobacter pylori infection in the Chinese population. Aliment Pharmacol Ther 2002; 16:813-7. [PMID: 11929401 DOI: 10.1046/j.1365-2036.2002.01235.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND A new rapid urine test was developed to detect anti-Helicobacter pylori antibody in urine using the principle of immunochromatography. The accuracy of this test in the Chinese population remains to be defined. AIM To evaluate a new rapid urine test for the diagnosis of H. pylori infection in the Chinese population. METHODS Eligible patients without previous treatment of H. pylori were recruited. In-house rapid urease test and histology were used as the gold standard. The rapid urine test (RAPIRUN H. pylori antibody) was performed and the results were compared with the gold standard. RESULTS One hundred and twenty-three patients were eligible for analysis and 61 (50%) were H. pylori positive by the gold standard. The rapid urine test showed a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 96.7%, 95.2%, 95.2%, 96.7% and 95.9%, respectively. Results were obtained within 20 min and no special laboratory support was required. CONCLUSIONS The rapid urine test by immunochromatography is highly accurate for the diagnosis of H. pylori infection in untreated Chinese patients.
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Xia HHX, Wong BCY, Wong WM, Tang VSY, Cheung HKL, Sham FNF, Fung FMY, Lai KC, Hu WHC, Chan CK, Lam SK. Optimal serological tests for the detection of Helicobacter pylori infection in the Chinese population. Aliment Pharmacol Ther 2002; 16:521-6. [PMID: 11876706 DOI: 10.1046/j.1365-2036.2002.01176.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Numerous serological tests for the detection of Helicobacter pylori infection have been developed. However, many perform poorly when evaluated in the Chinese population. AIM To search for optimal serological tests for the detection of H. pylori infection in Chinese patients. METHODS Consecutive dyspeptic patients referred for upper endoscopy were recruited. During endoscopy, gastric biopsies were taken for the CLOtest and histological examination. Patients were then given a 13C-urea breath test. Sera were used to test for H. pylori infection, employing three commercial enzyme-linked immunosorbent assay kits (pylori DTect, HP IgG and GAP IgG). Results were compared with the gold standard defined by the CLOtest, histology and 13C-urea breath test. RESULTS Among the 142 patients (47 male, 95 female; mean age, 49 years) recruited, 81 (57%) were H. pylori-positive, 57 (40%) were H. pylori-negative and four (3%) were defined to be indeterminate. Using a self-defined cut-off value after calculation, the best accuracies for the pylori DTect, HP IgG and GAP IgG tests were 97%, 91% and 80%, respectively. CONCLUSIONS The pylori DTect test is an optimal serological test for the detection of H. pylori infection in Hong Kong Chinese patients. The HP IgG test may be used as an alternative.
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Wigle DA, Chaparro C, Humar A, Hutcheon MA, Chan CK, Keshavjee S. Epstein-Barr virus serology and posttransplant lymphoproliferative disease in lung transplantation. Transplantation 2001; 72:1783-6. [PMID: 11740388 DOI: 10.1097/00007890-200112150-00012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Posttransplant lymphoproliferative disease (PTLD) is now a widely recognized complication of lung transplantation. In the current study, we present our experience with PTLD over a 15-year period, which includes the incidence rates in 242 lung allografts and the relative risk of developing PTLD in 146 patients with known pretransplantation Epstein-Barr virus (EBV) status. METHODS Inpatient and outpatient charts of 300 consecutive lung transplant recipients between 1984 and 1999 were retrospectively reviewed. RESULTS Twelve cases of PTLD were observed for a total incidence rate of 5.0%. Ten of these patients had pretransplantation EBV testing, and the consequent increase in relative risk for patients who were EBV negative was 6.8-fold. The mean time between organ transplantation and tissue diagnosis of PTLD was 17.6 months. Total 1-year survival rate from the time of diagnosis for the cohort was 58%, whereas 2-year survival rate was 50%. Median survival for the six patients who died was 4.5 months. CONCLUSIONS These data suggest that although EBV seronegativity does carry a 6.8-fold increase in the relative risk of developing PTLD, long-term survival despite the development of PTLD can be achieved, and thus EBV seronegativity by itself should not be considered a contraindication to lung transplantation.
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Chan CK, Agarwal A, Agarwal S, Agarwal A. Management of dislocated intraocular implants. OPHTHALMOLOGY CLINICS OF NORTH AMERICA 2001; 14:681-93. [PMID: 11787747 DOI: 10.1016/s0896-1549(05)70267-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Implant dislocation may occur in the absence of appropriate capsular or zonular support (PCIOL) (11,35,53) or following traumatic injury to anterior ocular tissues (ACIOL). (11,19,20) Other factors (e.g., advanced patient age, high myopia, previous vitrectomy, pseudoexfoliation syndrome, and certain connective tissue disorders) also may predispose implant dislocation. (9,52) Although reported for all types of IOLs, implant dislocation is becoming more manageable because of the advancement of surgical techniques. A dislocated ACIOL or PCIOL may be explanted, exchanged, or repositioned. (11,48,71) Repositioning the dislocated PCIOL in the ciliary sulcus with modern vitreoretinal techniques provides an optimal environment for visual recovery. (11,71) Implant repositioning techniques generally may be categorized into the external or the internal approaches. (8,11) The former involves external suturing methods for a primary or secondary implant in the absence of adequate capsular or zonular support (15,16,31,42,56,60,61,64,66,73,76) and the latter is achieved through modern pars plana techniques. 8,11,62,69) Recently, several implant repositioning methods gaining increasing acceptance include the scleral loop fixation, (45) the snare approach, (43) the use of the 25-gauge implant forceps, (13) temporary haptic externalization, (8,11,36,71) and the use of perfluorocarbon liquids. (1,28,40,41,44) The temporary haptic externalization method combines the best features of the external and the internal approaches, avoids complex intraocular maneuvers, and allows precise scleral fixation of the dislocated IOL on a consistent basis. (8,11,71) Endoscopy provides the surgeon with optimal viewing of the anterior retropupillary anatomy that is often difficult to appreciate (e.g., capsular-zonular complex, ciliary sulcus, anterior retina, and vitreous base). (6,11) As a result, precise haptic placement is possible during the repositioning process. (6,11) However, a three-dimensional birds-eye view is lacking, and there may be a steep learning curve with endoscopy. (11) Certain characteristics of a silicone plate implant may enhance implant dislocation. (11,33,34,46,49,58) Capsular contraction following an Nd:YAG posterior capsulotomv may result in a posterior dislocation of the silicone plate implant. (11,33,34,46,49,50,58) Special techniques are available for the retrieval of the slippery dislocated silicone plate implant from the retinal surface without causing injury. (33,58) Repositioning the plate implant anterior to capsular remnants or in the ciliary sulcus may lead to recurrent dislocation, and its removal is frequently the best option. (11) Placing a second implant in the presence of a disLocated implant is ill advised because subsequent surgical management becomes more complex. (11) Surgical options include removing the dislocated implant through a Limbal or pars plana incision with special techniques, (74,75) repositioning the dislocated implant after removing the second implant," and explanting both implants. (11) Considering the increased morbidities and complications associated with the management of double implants, the surgeon should avoid the placement of a second implant in the setting of a dislocated implant. (11)
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Xia HH, Wong BC, Wong KW, Wong SY, Wong WM, Lai KC, Hu WH, Chan CK, Lam SK. Clinical and endoscopic characteristics of non-Helicobacter pylori, non-NSAID duodenal ulcers: a long-term prospective study. Aliment Pharmacol Ther 2001; 15:1875-82. [PMID: 11736717 DOI: 10.1046/j.1365-2036.2001.01115.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The proportion of duodenal ulcers not associated with Helicobacter pylori infection or the use of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing. AIM To identify the clinical and endoscopic characteristics of non-H. pylori, non-NSAID duodenal ulcers. METHODS Clinical and endoscopic data and H. pylori status were prospectively collected from consecutive patients who underwent upper endoscopy from 1997 to 1999. Patients with duodenal ulcers were identified, and those with non-H. pylori, non-NSAID duodenal ulcers were analysed further. RESULTS A total of 11 717 upper endoscopies were performed in 8344 patients. Of these, 1153 (14%) had duodenal ulcers. Of 599 patients with active ulcers and known H. pylori status, 104 (17%) had ulcers not associated with H. pylori or the use of NSAIDs, 393 (66%) had ulcers associated with H. pylori alone, 51 (8.5%) had ulcers associated with the use of NSAIDs alone and 51 (8.5%) had ulcers associated with both. Multivariate logistic regression analysis revealed that the presence of concomitant diseases (odds ratio=15.0; 95% confidence interval, 8.64-25.9; P < 0.001) and the absence of epigastric pain/discomfort (odds ratio=0.52; 95% confidence interval, 0.29-0.91; P=0.022) were independent predictors for non-H. pylori, non-NSAID duodenal ulcers. CONCLUSIONS Non-H. pylori, non-NSAID duodenal ulcers exhibit certain distinct clinical and endoscopic characteristics. The presence of concomitant diseases is an important predictive factor.
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Peng C, Chan MN, Chan CK. The hygroscopic properties of dicarboxylic and multifunctional acids: measurements and UNIFAC predictions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:4495-4501. [PMID: 11757607 DOI: 10.1021/es0107531] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The role of water-soluble organic compounds on the hygroscopic properties of atmospheric aerosols has recently been the subject of many studies. In particular, low molecular weight dicarboxylic acids and some multifunctional organic acids have been found or are expected to exist in atmospheric aerosols in urban, semiurban, rural, and remote sites. Unlike for their inorganic counterparts, the hygroscopic properties of organic acids have not been well characterized. In this study, the hygroscopic properties of selected water-soluble dicarboxylic acids (oxalic acid, malonic acid, succinic acid, and glutaric acid) and multifunctional acids (citric acid, DL-malic acid, and L-(+)-tartaric acid) were studied using single droplets levitated in an electrodynamic balance at 25 degrees C. The water activities of bulk samples of dilute solutions were also measured. Solute evaporation was observed in the dicarboxylic acids but not in the multifunctional acids. Oxalic acid, succinic acid, and glutaric acid droplets crystallize upon evaporation of water, but, except for glutaric acid droplets, do not deliquesce even at 90% relative humidity (RH). Mass transfer limitation of the deliquescence process was observed in glutaric acid. Neither crystallization nor deliquescence was observed in malonic acid, citric acid, DL-malic acid, or L-(+)-tartaric acid. Malonic acid and these three hydroxy-carboxylic acids absorb water even at RH much lower than their respective deliquescence RH. The growth factor (Gf), defined as the ratio of the particle diameter at RH = 10% to that at RH = 90%, of oxalic acid and succinic acid was close to unity, indicating no hygroscopicity in this range. The remaining acids (malonic acid, glutaric acid, citric acid, malic acid, and tartaric acid) showed roughly similar hygroscopicity of a Gf of 1.30-1.53, which is similar to that of "more hygroscopic" aerosols in field measurements reported in the literature. A generalized equation for these four acids, Gf = (1-aw)-0.163, was developed to represent the hygroscopicity of these acids. Water activity predictions from calculations using the UNIFAC model were found to agree with the measured water activity data to within 40% for most of the acids but the deviations were as large as about 100% for malic acid and tartaric acid. We modified the functional group interaction parameters of the COOH(-H20, OH-H20, and OH-COOH pairs by fitting the UNIFAC model with the measured data. The modified UNIFAC model improves the agreement of predictions and measurements to within 38% for all the acids studied.
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Che CM, Xia BH, Huang JS, Chan CK, Zhou ZY, Cheung KK. Photoluminescent metal-sulfur clusters derived from tetrathiometalates: metal-to-metal charge-transfer excited states of d0-d10 heterobimetallic sulfido clusters with bulky phosphine ligands. Chemistry 2001; 7:3998-4006. [PMID: 11596942 DOI: 10.1002/1521-3765(20010917)7:18<3998::aid-chem3998>3.0.co;2-h] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Reactions of MS4(2-) (M = Mo, W) with M'(PCy3)X (M'=Ag/Au, X= ClO4/Cl) and [Cu2(dcpm)2(MeCN)2](ClO4)2 (dcpm = bis(dicyclohexylphosphino)methane) afforded heterometallic sulfido clusters [M'2(PCy3)2(MS4)] (M=Mo, M'=Au: 2; M=W, M'=Ag: 3, Au: 4) and [Cu4(dcpm)4(MS4)](ClO4)2 (M=Mo: 5 x (ClO4)2, W: 6 x (ClO4)2), all of which, except 4, have been characterized by X-ray structure determination. Clusters 5 x(ClO4)2 and 6 x (ClO4)2 feature unusual 16-membered [Cu4P5C4] metallamacrocycles formed on the respective tetrathiometalate anion templates and have unusually long Cu-S bonds and Cu...M distances for metal sulfur clusters that contain a saddle-shaped [Cu4MS4] core. Low-energy absorption bands are observed in their electronic spectra at approximately 562 and 467 nm, respectively, assignable to MMCT transitions; quasireversible reduction waves are observed with E(1/2) = -1.43 (52+) and -1.78 V (62+) versus FeCp2(0/+); and they are emissive either in the solid state or in solution. The emission of 6(2+) can be quenched by both electron acceptors, such as methylviologen, or electron donors, such as aromatic amines, with the excited state reduction potential E(62+*/6+) estimated to be approximately 1.13V versus a normal hydrogen electrode.
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Chan CK, Siegel LS. Phonological processing in reading Chinese among normally achieving and poor readers. J Exp Child Psychol 2001; 80:23-43. [PMID: 11511133 DOI: 10.1006/jecp.2000.2622] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ninety-four children in grades one to six (7 to 12 years old) in Hong Kong were individually administered a Chinese reading test consisting of 80 characters that varied in frequency (high or low) and orthographic structure (simple or complex). Phonological processing tasks, including short-term memory, pseudo-character recognition, and tone discrimination, were also administered. During reading, younger normal and poor readers made more semantic and visual errors, whereas older and normally achieving children made more phonologically related errors. Normally achieving readers also performed at a higher level than poor readers on short-term memory, pseudo-character recognition, and tone discrimination tasks. Phonological processing apparently plays a significant part in the development of reading skills in Chinese.
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Kheowan OU, Chan CK, Zykov VS, Rangsiman O, Müller SC. Spiral wave dynamics under feedback derived from a confined circular domain. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 64:035201. [PMID: 11580380 DOI: 10.1103/physreve.64.035201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2001] [Indexed: 05/23/2023]
Abstract
Spiral waves are induced in a thin layer of the light-sensitive Belousov-Zhabotinsky reaction and controlled by a time-dependent uniform illumination. The intensity of the illumination is taken to be proportional to the average wave activity observed within a circular domain of the reaction layer. Stabilization and destabilization of spiral waves, as well as the existence of additional types of attractors, are demonstrated. A simple mathematical description is proposed in order to explain the existence of the attractors and the dependence of their size on the time delay in the feedback loop.
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Lau LL, Hung CT, Chan CK, Chow B, Chui PT, Ho B, Kung MC, Lui J, Hui T, Ho E, Chan SF, So HY. Anaesthetic clinical indicators in public hospitals providing anaesthetic care in Hong Kong: prospective study. Hong Kong Med J 2001; 7:251-60. [PMID: 11590266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
OBJECTIVES To assess the quality of anaesthetic services as defined in the six anaesthetic clinical indicators against preset standards and to identify risk factors for adverse events in the recovery room. DESIGN Prospective study. SETTING All public hospitals providing anaesthetic care in Hong Kong. PATIENTS Eighteen thousand, seven hundred and fifty-nine patients receiving elective or emergency anaesthesia administered by anaesthetists from June 1998 to July 1998. MAIN OUTCOME MEASURES Patient demographics, American Society of Anesthesiologists status, category and nature of operation, presence of preoperative anaesthetic visit in ward, type of anaesthesia, reasons for a recovery room stay of more than a 2-hour duration, intubation to relieve respiratory distress in the recovery room, presence of hypothermia in the recovery room for operations lasting more than 2 hours, and dental or ocular injuries attributable to anaesthesia. RESULTS There are two major findings from this study. Firstly, a high incidence of hypothermia in the recovery room was reported. Secondly, a greater risk of prolonged stay in the recovery room was identified for patients older than 65 years, major operations, and anaesthetic techniques using combined general and regional anaesthesia. CONCLUSION The six anaesthetic clinical indicators reflected the provision of anaesthetic care in public hospitals in Hong Kong. Good compliance to the preset standard of the anaesthetic clinical indicators was achieved during the study period.
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Leung CC, Tam CM, Chan SL, Chan-Yeung M, Chan CK, Chang KC. Efficacy of the BCG revaccination programme in a cohort given BCG vaccination at birth in Hong Kong. Int J Tuberc Lung Dis 2001; 5:717-23. [PMID: 11495262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
SETTING Revaccination of tuberculin-negative school-children is a regular practice in Hong Kong. OBJECTIVE To assess the efficacy of BCG revaccination guided by tuberculin skin testing. METHOD A cohort of 303,692 children vaccinated at birth was followed through the tuberculosis notification register for the development of active disease. The percentage of cohort who participated in the BCG revaccination program during primary school was estimated from the vaccination statistics of the Hong Kong Department of Health. The BCG revaccination history of identified cases was ascertained through vaccination cards and clinic records. RESULTS A total of 85.2% of the cohort participated in the BCG revaccination programme; 79.7% of the participants were tuberculin-negative and revaccinated; 343 developed tuberculosis after the age of 11; 302 were among the participants in the programme while 41 were not. The tuberculosis incidence was 16.5 and 12.9 per 100,000 person-years for participants and non-participants, respectively (RR 1.28, 95%CI 0.92-1.77). Among the participants, tuberculosis incidence was 12.5 and 32.0/100,000 person-years, respectively, for the tuberculin-negative/BCG revaccinated group and the tuberculin-positive/non-revaccinated group (RR 0.39, 95%CI 0.31-0.49). CONCLUSION This study failed to demonstrate any significant difference in the incidence rates of tuberculosis among participants and non-participants in a school BCG revaccination programme. The increased risk for tuberculosis in the tuberculin-positive group does not support the use of the tuberculin testing for detection of immunity conferred by neonatal BCG vaccination.
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Miletin MS, Chan CK. The use of guidelines for the empirical treatment of hospital-acquired pneumonia. Can Respir J 2001; 8:255-60. [PMID: 11521141 DOI: 10.1155/2001/713457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Several practice guidelines for the empirical antimicrobial treatment of hospital-acquired pneumonia (HAP) have been developed, but the acceptance and use of such guidelines are unknown. OBJECTIVE To assess physicians' use of empirical HAP guidelines published by the American Thoracic Society (ATS) and by The University Health Network, Toronto, Ontario. DESIGN A retrospective assembly and chart review. SETTING A university teaching hospital. PATIENTS One hundred fifteen consecutive patients who had been diagnosed with pneumonia more than 48 h after admission to hospital over a 10-month period. RESULTS The charts of 115 patients were reviewed. Seventy-five patients (65%) were treated empirically. Forty patients (35%) were treated based on microbiological data that were available before the initiation of antibiotics. Patients who received nonempirical treatment for HAP had a significantly greater acuity of illness than the empirically treated group. Thirty-seven patients (49%) who received empirical therapy were treated according to either ATS or hospital guidelines for HAP. The use of guideline-concordant antimicrobial therapy had no measurable effect on in-hospital mortality (eight of 37 patients [21.6%] versus seven of 38 patients [18.4%], P=0.96) or median length of stay (19 days versus 21 days, P=0.30). Patients whose treatment did not follow guideline recommendations tended to receive appropriate antimicrobial coverage more often than did those patients whose treatment was guideline concordant (15 of 18 patients [83%] versus six of 11 patients [55%], P=0.49). CONCLUSIONS Institutional and ATS guidelines for the empirical treatment of HAP are less widely used than would be predicted by chance at The University Health Network. The clinical utility of these guidelines remains to be proven.
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