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Biomedical subjects

M C Cheung

Publications and source records attributed to M C Cheung.

At least 19 recordsLinked to original sources
PubMed2006

Intrarectal administration of lidocaine gel versus plain lubricant gel for pain control during transrectal ultrasound-guided extensive 10-core prostate biopsy in Hong Kong Chinese population: prospective double-blind randomised controlled trial.

OBJECTIVE: To compare the level of pain experienced by patients during transrectal ultrasound-guided prostatic biopsy using intrarectal 2% lidocaine gel versus plain lubricant gel. DESIGN: Prospective double-blind randomised controlled trial. SETTING: Regional hospital, Hong Kong. PATIENTS: From March 2002 to December 2003, patients who underwent ultrasound-guided prostate biopsy at a Geriatric Urology Centre. MAIN OUTCOME MEASURES: Pain and discomfort scores measured by horizontal visual analogue scales. RESULTS: A total of 338 consecutive patients were randomised to lidocaine gel or plain lubricant gel groups. The two groups were statistically similar in demographic and disease characteristics. There were no significant statistical differences in pain or discomfort score in the lidocaine gel and plain lubricant groups--pain score: 1.75 versus 1.79 (P=0.66) on day 0 and 0.21 versus 0.15 (P=0.97) on day 1; discomfort score: 0.79 versus 0.77 (P=0.86) on day 0 and 0.12 versus 0.12 (P=0.76) on day 1. No major complications were recorded in this cohort. CONCLUSIONS: Transrectal ultrasound-guided trucut biopsy of the prostate can be safely performed with no anaesthesia in Chinese patients. Pain and discomfort are minimal. It was found that 2% lidocaine gel has no statistical therapeutic or analgesic benefit over plain lubricant gel.

Administration, Rectal↗
PubMed2005

Laparoscopic nephrectomy: an early experience at Queen Mary Hospital.

OBJECTIVE: To report our early experience of laparoscopic nephrectomy. DESIGN: Prospective data collection. SETTING: Queen Mary Hospital, Hong Kong. PATIENTS: Transperitoneal laparoscopic nephrectomies were performed on 40 patients between July 1997 and December 2002. MAIN OUTCOME MEASURES: Demographic and perioperative data including operating time, blood loss, postoperative pain score, analgesic requirement, complications, time to resume oral intake, ambulatory state, and length of hospital stay. RESULTS: Laparoscopic nephrectomy was performed for 21 solid renal masses, five transitional cell carcinomas, and 14 non-functioning kidneys. Seven (17.5%) patients had previous abdominal surgery. The mean body mass index of the patients was 23.9 kg/m(2) and the mean operating time was 229 minutes. The mean estimated blood loss was 370 mL, and two patients required conversion to open surgery because of intra-operative bleeding. Other complications include diaphragmatic injury, port-site bleeding, chyle leakage, bleeding peptic ulcer, and myocardial ischaemia. The postoperative mean analgesic requirement was 26 mg of morphine sulphate equivalent. The mean time for patients to resume oral diet and full ambulation was 1.3 and 2.8 days, respectively, and the mean length of hospital stay was 6.7 days. The mean diameter of the solid renal tumour was 4.1 cm and the surgical margins of all resected specimen for malignant tumours were negative. CONCLUSION: Laparoscopic nephrectomy is a safe and efficacious approach for resection of benign non-functioning kidneys and malignant renal tumours.

Blood Loss, Surgical↗
PubMed2003

A prospective randomized controlled trial on ureteral stenting after ureteroscopic holmium laser lithotripsy.

PURPOSE: A prospective randomized controlled trial was conducted to evaluate whether postoperative ureteral stenting is necessary after ureteroscopic laser lithotripsy. MATERIALS AND METHODS: A total of 58 patients with unilateral ureteral stones were randomized into either stented or unstented groups. Ureteroscopic laser lithotripsy was performed using a semirigid ureteroscope (6.5/7Fr) and holmium laser without ureteral orifice dilation. There were no selection criteria regarding stone size, location, preoperative ureteral obstruction and hydronephrosis. Endoscopic evidence of stone impaction or mucosal edema/damage did not exclude a patient from the study. Ureteral perforation on completion retrograde pyelogram was the only intraoperative criterion for study exclusion. Postoperative pain scores and symptoms were recorded. Excretory urography was performed to document stone-free status and stricture formation. Radionuclide scan was performed selectively to exclude functional obstruction when ureteral narrowing was found on excretory urogram. RESULTS: Mean stone size +/- SD was 9.7 +/- 4.0 mm. (range 4 to 27). Proximal ureteral stones accounted for 43% of all stones. Stented and unstented groups were comparable with respect to demographic data, stone parameters, preoperative obstruction and hydronephrosis. There was no significant difference in operating time, laser energy used, stone impaction and mucosal edema/damage between the 2 groups. Postoperative pain and symptoms were more severe and frequent (p <0.05) in the stented group. However, there was no difference in the incidence of postoperative sepsis and unplanned medical visits. The stone-free and stricture formation rates showed no statistical difference between the 2 groups. CONCLUSIONS: Ureteral stenting is not necessary after uncomplicated ureteroscopic laser lithotripsy for ureteral stones. Ureteral stent increases the incidence of pain and urinary symptoms but does not prevent postoperative urinary sepsis and unplanned medical visits. Severity of preoperative obstruction and intraoperative ureteral trauma were not shown to be determining factors for stenting.

Adult↗
PubMed2002

Association of plasma phospholipid transfer protein activity with IDL and buoyant LDL: impact of gender and adiposity.

Current data suggest that phospholipid transfer protein (PLTP) has multiple metabolic functions, however, its physiological significance in humans remains to be clarified. To provide further insight into the role of PLTP in lipoprotein metabolism, plasma PLTP activity was measured, and lipoproteins were analyzed in 134 non-diabetic individuals on a controlled diet. Insulin sensitivity index (Si) and body fat composition were also determined. Plasma PLTP activity was comparable between men (n=56) and women (n=78). However, in women but not in men, plasma PLTP activity was positively correlated with cholesterol, triglyceride, low density lipoprotein (LDL) cholesterol, and apolipoprotein (apo) B (r=0.38-0.45, P< or =0.001), and with body mass index (BMI), subcutaneous and intra-abdominal fat (SCF, IAF) (r=0.27-0.29, P<0.02). Among the different apo B-containing lipoproteins (LpB) in women, PLTP was most highly correlated with intermediate density lipoproteins (IDL) and buoyant LDL (r=0.45-0.46, P<0.001). The correlation with IDL was significant only in women with BMI < or =27.5 kg/m(2) (n=56). In men with BMI < or =27.5 kg/m(2) (n=35), PLTP activity was significantly correlated with buoyant LDL (r=0.40, P<0.02) and high density lipoprotein (HDL) (r=0.43, P<0.01). These data provide evidence for a role of PLTP in LpB metabolism, particularly IDL and buoyant LDL. They also suggest that gender and obesity-related factors can modulate the impact of PLTP on LpB.

Adipose Tissue↗
PubMed2002

Prospective study on ultrasonography plus plain radiography in predicting residual obstruction after extracorporeal shock wave lithotripsy for ureteral stones.

OBJECTIVES: To compare ultrasonography (US) and plain radiography with intravenous urography (IVU) in predicting ureteral obstruction after in situ extracorporeal shock wave lithotripsy (ESWL) for ureteral stones. METHODS: From April 1998 to September 2000, 100 consecutive patients with solitary ureteral stones were treated by primary in situ ESWL. ESWL failures were salvaged by ureteroscopic lithotripsy. Ninety-three patients completed the follow-up assessment. US and IVU were performed when plain radiography showed no residual stone. The occurrence of hydronephrosis on US was compared with IVU, the reference standard for ureteral obstruction. RESULTS: Of the 93 patients, 72 were men and 21 women (mean age 52 years; mean stone size 11.2 mm). ESWL successfully treated 70 ureteral stones (75%), and the 23 failures were treated by ureteroscopic lithotripsy. Sixty-nine patients without hydronephrosis on US had no ureteral obstruction on IVU. Of the 24 patients who had hydronephrosis on US, 8 had ureteral obstruction on IVU. Of the 85 patients who had no ureteral obstruction on IVU, 69 patients showed no evidence of hydronephrosis on US. However, all patients with ureteral obstruction on IVU demonstrated hydronephrosis on US. The sensitivity, specificity, and positive and negative predictive value concerning sonographic hydronephrosis in the prediction of ureteral obstruction was 100%, 81%, 33%, and 100%, respectively. US alone could not define the cause of ureteral obstruction. CONCLUSIONS: Plain abdominal radiography plus US is highly sensitive for screening ureteral obstruction after primary in situ ESWL for ureteral calculi. It can save up to 74% of patients from the potential risk of IVU. The detection of the cause of obstruction by IVU is only necessary when sonographic evidence of hydronephrosis is present.

Adult↗
PubMed2001

Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease.

BACKGROUND: Both lipid-modifying therapy and antioxidant vitamins are thought to have benefit in patients with coronary disease. We studied simvastatin-niacin and antioxidant-vitamin therapy, alone and together, for cardiovascular protection in patients with coronary disease and low plasma levels of HDL. METHODS: In a three-year, double-blind trial, 160 patients with coronary disease, low HDL cholesterol levels and normal LDL cholesterol levels were randomly assigned to receive one of four regimens: simvastatin plus niacin, vitamins, simvastatin-niacin plus antioxidants; or placebos. The end points were arteriographic evidence of a change in coronary stenosis and the occurrence of a first cardiovascular event (death, myocardial infarction, stroke, or revascularization). RESULTS: The mean levels of LDL and HDL cholesterol were unaltered in the antioxidant group and the placebo group; these levels changed substantially (by -42 percent and +26 percent, respectively) in the simvastatin-niacin group. The protective increase in HDL2 with simvastatin plus niacin was attenuated by concurrent therapy with antioxidants. The average stenosis progressed by 3.9 percent with placebos, 1.8 percent with antioxidants (P=0.16 for the comparison with the placebo group), and 0.7 percent with simvastatin-niacin plus antioxidants (P=0.004) and regressed by 0.4 percent with simvastatin-niacin alone (P<0.001). The frequency of the clinical end point was 24 percent with placebos; 3 percent with simvastatin-niacin alone; 21 percent in the antioxidant-therapy group; and 14 percent in the simvastatin-niacin-plus-antioxidants group. CONCLUSIONS: Simvastatin plus niacin provides marked clinical and angiographically measurable benefits in patients with coronary disease and low HDL levels. The use of antioxidant vitamins in this setting must be questioned.

Antioxidants↗
PubMed2001

Plasma phospholipid transfer protein activity in patients with low HDL and cardiovascular disease treated with simvastatin and niacin.

Plasma phospholipid transfer protein (PLTP) is an important modulator of high-density lipoprotein (HDL) metabolism, regulating its particle size, composition, and mass. In patients with low HDL and cardiovascular disease (CVD), plasma PLTP activity is positively correlated with the concentration of HDL particles containing apo A-I but not apo A-II (Lp(A-1)). We recently completed a study to determine the effect of simvastatin and niacin (S-N) therapy on disease progression/regression in these patients, and found that this therapy selectively increased Lp(A-I). To determine if PLTP was also increased with this drug therapy, we measured the PLTP activity in the plasma of 30 of these patients obtained at baseline and after 12 months of therapy, and compared the changes to a similar group of 31 patients who received placebo for the drugs. No significant increase in PLTP activity was observed in either group of patients. However, changes in apo A-I and A-II between these two time points were correlated with the corresponding change in PLTP activity. The correlation coefficients were r=0.57 (P=0.001) and r=0.43 (P=0.02) for apo A-I, and r=0.54 (P=0.002) and r=0.41 (P=0.02) for apo A-II in the placebo and S-N group, respectively. At baseline, PLTP activity correlated positively with the percent of plasma apo A-I associated with Lp(A-I) (r=0.38, P=0.04) and the amounts of apo A-I in these particles (r=0.43, P=0.02). These relationships persisted in patients who took placebo for 12 months (r=0.46, P=0.009 and r=0.37, P=0.04, respectively), but was attenuated in those treated with S-N. These data indicate that S-N-induced increase in Lp(A-I) was PLTP-independent. It also confirms our previous observation that an interrelationship exists between PLTP and apo-specific HDL particle subclasses in CVD patients with low HDL, and that this relationship is altered by drug intervention.

Adult↗
PubMed2001

Costimulation blockade, busulfan, and bone marrow promote titratable macrochimerism, induce transplantation tolerance, and correct genetic hemoglobinopathies with minimal myelosuppression.

Mixed hemopoietic chimerism has the potential to correct genetic hemological diseases (sickle cell anemia, thalassemia) and eliminate chronic immunosuppressive therapy following organ transplantation. To date, most strategies require either recipient conditioning (gamma-irradiation, depletion of the peripheral immune system) or administration of "mega" doses of bone marrow to facilitate reliable engraftment. Although encouraging, many issues remain that may restrict or prevent clinical application of such strategies. We describe an alternative, nonirradiation based strategy using a single dose of busulfan, costimulation blockade, and T cell-depleted donor bone marrow, which promotes titratable macrochimerism and a reshaping of the T cell repertoire. Chimeras exhibit robust donor-specific tolerance, evidenced by acceptance of fully allogeneic skin grafts and failure to generate donor-specific proliferative responses in an in vivo graft-versus-host disease model of alloreactivity. In this model, donor cell infusion and costimulation blockade without busulfan were insufficient for tolerance induction as donor-specific IFN-gamma-producing T cells re-emerged and skin grafts were rejected at approximately 100 days. When applied to a murine beta-thalassemia model, this approach allows for the normalization of hemologic parameters and replacement of the diseased red cell compartment. Such a protocol may allow for clinical application of mixed chimerism strategies in patients with end-stage organ disease or hemoglobinopathies.

Animals↗
PubMed2001

Antibodies to human fetal erythroid cells from a nonimmune phage antibody library.

The ability to isolate fetal nucleated red blood cells (NRBCs) from the maternal circulation makes possible prenatal genetic analysis without the need for diagnostic procedures that are invasive for the fetus. Such isolation requires antibodies specific to fetal NRBCs. To generate a panel of antibodies to antigens present on fetal NRBCs, a new type of nonimmune phage antibody library was generated in which multiple copies of antibody fragments are displayed on each phage. Antibody fragments specific for fetal NRBCs were isolated by extensive predepletion of the phage library on adult RBCs and white blood cells (WBCs) followed by positive selection and amplification on fetal liver erythroid cells. After two rounds of selection, 44% of the antibodies analyzed bound fetal NRBCs, with two-thirds of these showing no binding of WBCs. DNA fingerprint analysis revealed the presence of at least 16 unique antibodies. Antibody specificity was confirmed by flow cytometry, immunohistochemistry, and immunofluorescence of total fetal liver and adult RBCs and WBCs. Antibody profiling suggested the generation of antibodies to previously unknown fetal RBC antigens. We conclude that multivalent display of antibodies on phage leads to efficient selection of panels of specific antibodies to cell surface antigens. The antibodies generated to fetal RBC antigens may have clinical utility for isolating fetal NRBCs from maternal circulation for noninvasive prenatal genetic diagnosis. Some of the antibodies may also have possible therapeutic utility for erythroleukemia.

Antibodies, Monoclonal↗
PubMed2001

Primary actinomycosis mimicking urachal carcinoma.

We report a case of urachal actinomycosis that presented with a progressively enlarging infraumbilical mass associated with umbilical discharge. Computed tomography revealed an extraperitoneal mass involving the dome of the bladder. The possible diagnosis included a malignant urachal neoplasm or chronic inflammatory mass. Partial cystectomy and excision of the mass was performed. The pathologic examination revealed actinomycosis. The patient was treated with a 6-month course of antibiotics. No recurrence was noted 1 year postoperatively.

Actinomycosis↗
PubMed2001

Outpatient ureteroscopy: predictive factors for postoperative events.

OBJECTIVES: To identify risk factors that can predict the postoperative events of outpatient ureteroscopy. METHODS: The data of 329 consecutive patients who underwent outpatient ureteroscopy from January 1996 to July 2000 were analyzed. Patient selection for outpatient surgery was based solely on their general medical status and social factors. Eighty-three percent of the procedures were therapeutic ureteroscopy. The reported postoperative events included sleep disturbances, postoperative pain score, emesis, unplanned admission, and other complications. These were compared with the various patient and operative factors. Multivariate analysis was performed to identify the predictive factors for different postoperative events. RESULTS: The overall success rate of ureteroscopic access to the pathologic site was 99.7%. Most of the therapeutic ureteroscopy performed was ureteroscopic lithotripsy (93%), with a stone-free rate of 91%. Ninety-seven percent of the operations were completed within 90 minutes, and 98% of patients were fit for discharge within 5 hours. Female patients reported more symptoms on the way home (25.8% versus 16%, P = 0.047) and more postoperative emesis (14.4% versus 2.1%, P <0.001). The postoperative pain score on day 1 was higher if the operation had lasted more than 60 minutes (2.4 versus 1.5, P = 0.002). Patients who received postoperative stenting had a higher postoperative pain score on day 3 (1.1 versus 0.4, P <0.001) and a higher complication rate compared with those who required no postoperative stenting (16.8% versus 4%, P <0.001). No predictive factors for unplanned admission were identified. CONCLUSIONS: Ureteroscopy can be successfully performed in an outpatient setting. Although the early postoperative pain was associated with nature of the operation (which could not be changed), the subsequent postoperative pain and complications were associated with ureteral stenting, which could be reduced by selective stenting. Unplanned admissions could not be predicted.

Ambulatory Surgical Procedures↗
PubMed2001

Outpatient holmium laser lithotripsy using semirigid ureteroscope. Is the treatment outcome affected by stone load?

OBJECTIVES: To compare the outcome of outpatient ureteroscopic laser lithotripsy (URSL) for ureteral stone larger than 10 mm in longest diameter (group 1) with those less than or equal to 10 mm (group 2). METHODS: 134 patients with solitary ureteral stone were treated by outpatient URSL. No exclusion criteria with regards to stone size, level or composition were applied. Semirigid ureteroscopy and holmium-YAG laser lithotripsy was performed under general anaesthesia as outpatient procedure. Radiological follow-up by intravenous urogram was performed 3 months postoperatively. Patients' demographic data, stone parameters, operative details and treatment outcome were collected prospectively and compared between the two groups. RESULTS: Among the 134 ureteral stones, 41(31%) were larger than 10 mm. Group 1 contained more upper and middle ureteral stones than group 2 (68 vs. 40% p = 0.001). Operating time was significantly longer for group 1 (68.9 vs. 46.8 min, p<0.001) and postoperative stenting rate was higher (83 vs. 60%, p = 0.01). There was no difference between the groups in terms of 3 months stone clearance rate (92.7 vs. 91.4%, p = 0.8). Complication rate was higher in group 1 (22 vs. 5.4%, p = 0.004) especially for lower stones (46.2 vs. 5.4%, p = 0.001) but most of which were minor complications that were treated conservatively. One patient in group 1 (2.4%) developed ureteral stricture at the longstanding stone impaction site despite postoperative stenting. The stricture resolved subsequent to balloon dilatation. CONCLUSIONS: URSL can treat stones larger than 10 mm in longest diameter at all levels safely and effectively in an outpatient setting.

Adult↗
PubMed2001

Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL.

One strategy for treating coronary artery disease (CAD) patients with low HDL cholesterol (HDL-C) is to maximally increase the HDL-C to LDL-C ratio by combining lifestyle changes with niacin (N) plus a statin. Because HDL can prevent LDL oxidation, the low-HDL state also may benefit clinically from supplemental antioxidants. Lipoprotein changes over 12 months were studied in 153 CAD subjects with low HDL-C randomized to take simvastatin and niacin (S-N), antioxidants (vitamins E and C, beta-carotene, and selenium), S-N plus antioxidants (S-N+A), or placebo. Mean baseline plasma cholesterol, triglyceride, LDL-C, and HDL-C levels of the 153 subjects were 196, 207, 127, and 32 mg/dL, respectively. Without S-N, lipid changes were minor. The S-N and S-N+A groups had comparably significant reductions (P</=0.001) in plasma cholesterol, triglyceride, and LDL-C. However, increases in HDL-C, especially HDL(2)-C, were consistently higher in the S-N group than in the S-N+A group (25% vs 18% and 42% vs 0%, respectively). With S-N, but not with S-N+A, there was a selective increase in apolipoprotein (apo) A-I (64%) in HDL particles containing apo A-I but not A-II [Lp(A-I)] and their particle size. Thus, in CAD patients with low HDL-C, S-N substantially increased HDL(2)-C, Lp(A-I), and HDL particle size. These favorable responses were blunted by the antioxidants used owing to a striking selective effect on Lp(A-I). This unexpected adverse interaction between antioxidants and lipid therapy may have important implications for the management of CAD.

Adult↗
PubMed2001

GPI-specific phospholipase D associates with an apoA-I- and apoA-IV-containing complex.

Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) is abundant in serum and associates with high density lipoproteins (HDL). We have characterized the distribution of GPI-PLD among lipoproteins in human plasma. Apolipoprotein (apo)-specific lipoproteins containing apoB (Lp[B]), apoA-I and A-II (Lp[A-I, A-II]), or apoA-I only (Lp[A-I]) were isolated using dextran sulfate and immunoaffinity chromatography. In six human plasma samples with HDL cholesterol ranging from 39 to 129 mg/dl, 79 +/- 14% (mean +/- SD) of the total plasma GPI-PLD activity was associated with Lp[A-I], 9 +/- 12% with Lp[A-I, A-II], and 1 +/- 1% with Lp[B]; and 11 +/- 10% was present in plasma devoid of these lipoproteins. Further characterization of the GPI-PLD-containing lipoproteins by gel-filtration chromatography and nondenaturing polyacrylamide and agarose gel electrophoresis revealed that these apoA-I-containing particles/complexes were small (8 nm) and migrated with pre-beta particles on agarose electrophoresis. Immunoprecipitation of GPI-PLD with a monoclonal antibody to GPI-PLD co-precipitated apoA-I and apoA-IV but little or no apoA-II, apoC-II, apoC-III, apoD, or apoE. In vitro, apoA-I but not apoA-IV or bovine serum albumin interacted directly with GPI-PLD, but did not stimulate GPI-PLD-mediated cleavage of a cell surface GPI-anchored protein. Thus, the majority of plasma GPI-PLD appears to be specifically associated with a small, discrete, and minor fraction of lipoproteins containing apoA-I and apoA-IV. -- Deeg, M. A., E. L. Bierman, and M. C. Cheung. GPI-specific phospholipase D associates with an apoA-I- and apoA-IV-containing complex. J. Lipid Res. 2001. 42: 442--451.

Adult↗
PubMed2000

Outpatient ureteroscopic lithotripsy: selective internal stenting and factors enhancing success.

PURPOSE: To evaluate a policy of selective, short-duration internal stenting after outpatient ureteroscopic laser lithotripsy. PATIENTS AND METHODS: From January 1997 to April 1998, 62 patients (34 male, 28 female) with a mean age of 50 (range 21-80) years underwent outpatient ureteroscopic lithotripsy using a holmium laser (365 microm; 0.5-1.4J/5-10 Hz) and 6F/7.5F semirigid ureteroscope. Internal stents were inserted selectively in patients with severe preoperative obstruction (intravenous urogram finding), tight stone impaction (endoscopic finding), or significant residual obstruction (on-table retrograde pyelogram finding) despite stone clearance. Patient demographics, stone measures, stone clearance rates, complications, postoperative pain scores, analgesic requirement, and follow-up imaging were compared for the stented and unstented patients. RESULTS: With the present criteria of selective internal stenting, stents were inserted in 56% of the patients for a mean duration of 3.6 weeks. Excluding those patients with residual stones requiring further interventions, the stenting rate was 39% with a mean duration of 1.9 weeks. There was no difference in patient characteristics, stone burden, and stone levels between the stented and unstented group. The mean operating time for the unstented group was shorter than for the stented group (45.6 minutes v 56.6 minutes; P = 0.03). The stone clearance rates were similar for the two groups (96% v 97%), but the complication rate of the stented group was higher (8.6% v 3.7%). The mean postoperative pain score and analgesic requirement were similar in the two groups on postoperative day 1 but significantly less in the unstented group on day 3. CONCLUSIONS: The criteria for selective internal stenting are useful in determining when a stent should be used. By omitting the stent insertion in the absence of these criteria, operating time, postoperative pain, and analgesic requirement were reduced without increasing the complication rate. Ureteral stricturing was absent despite the low stenting rate.

Adult↗