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Biomedical subjects

K L Leung

Publications and source records attributed to K L Leung.

At least 19 recordsLinked to original sources
PubMed2006

Laparoscopic total colectomy for colorectal cancers: a comparative study.

BACKGROUND: No previous report could be found in the literature comparing laparoscopic and open total colectomy for colorectal cancers, especially synchronous colorectal cancers. This study aimed to compare the short-term clinical outcomes and oncologic results of laparoscopic and open total colectomy or proctocolectomy for colorectal cancers. METHODS: Between July 1997 and January 2005, six patients with colorectal cancers underwent elective laparoscopic total colectomy or proctocolectomy at the authors' institution. Clinical data for 12 patients who underwent elective open total colectomy or proctocolectomy for colorectal cancers during the same period were prospectively collected and compared. RESULTS: The median follow-up periods were 43.9 months for the laparoscopic group and 48.2 months for the open group. Conversion to open procedure was required for one patient (16.7%) in the laparoscopic group because of bleeding. The median operative time was significantly longer in the laparoscopic group (427.5 min; range, 280-480 min vs 172.5 min; range, 90-260 min; p = 0.001). The patients in the laparoscopic group required a significantly shorter duration of parenteral analgesia (3 vs 5 days; p = 0.01), but there were no differences in time to first bowel motion, time to resumption of diet, time to full ambulation, and duration of hospital stay between the two groups. Perioperative morbidity rates were comparable between the two groups, and there was no operative mortality. The oncologic results, including number of lymph nodes removed, recurrence rates, and survival rates, were similar in the two groups. CONCLUSIONS: Laparoscopic total colectomy has short-term clinical outcomes (postoperative recovery and perioperative morbidity and mortality rates) and oncologic results similar to those of open surgery for treating patients with colorectal cancers. Our study has shown that the only advantage of laparoscopic over open surgery is a shorter duration of analgesic requirement, but at the expense of a longer operative time.

Aged↗
PubMed2006

A low cost, non-individualized surround sound system based upon head related transfer functions: an ergonomics study and prototype development.

This paper reports on the types and magnitudes of localization errors of simulated binaural direction cues generated using non-individualized, head-related transfer functions (HRTFs) with different levels of complexity. Four levels of complexity, as represented by the number of non-zero coefficients of the associated HRTF filters (128, 64, 32, 18 non-zero coefficients), were studied. Experiment 1 collected 1728 data runs that were exhaustive combinations of the four levels of complexity, nine simulated directions of sound (no direction (i.e., diotical-mono), 0 degrees , 45 degrees , 90 degrees , 135 degrees , 180 degrees , 225 degrees , 270 degrees , and 315 degrees azimuth angles at 0 degrees elevation), two repetitions, and 24 participants). Binaural cues generated from HRTFs of reduced complexity (from 128 to 18 non-zero coefficients) produced significantly higher localization errors for the directions of 45 degrees , 135 degrees , 225 degrees , and 315 degrees azimuth angles (p<0.01). From the directions of 0 degrees , 90 degrees , and 270 degrees azimuth angles, the cues produced by HRTFs with reduced complexity did not affect the localization error (p>0.2). Surprisingly, cues produced by HRTFs of 128 non-zero coefficients did not have the lowest number of errors. From 45 degrees , 135 degrees , 225 degrees , and 315 degrees , the lowest numbers of errors were obtained from cues produced by HRTFs of 64, 32, 32, and 64 non-zero coefficients, respectively. Based on these findings, a prototype virtual headphone-based surround-sound (VHSS) system was developed. A double-blind usability experiment with 32 participants indicated that the prototype VHSS system received significantly better surround-sound ratings than did a Dolby stereo system (p<0.02). This paper reports results from an original ergonomics study and the application of these results to the design of a consumer product.

Acoustic Stimulation↗
PubMed2006

Denaturing HPLC for high-throughput screening of rifampicin-resistant Mycobacterium tuberculosis isolates.

OBJECTIVE: To evaluate the use of denaturation high-performance liquid chromatography (dHPLC) as a rapid method to detect rifampicin (RMP) resistance based on mutations in the rpoB gene in a high-volume laboratory setting. METHODS: A total of 132 RMP-resistant Mycobacterium tuberculosis strains with different rpoB mutation were used to optimise the running condition of dHPLC as a pilot study. A blind correlation study was subsequently done between dHPLC and in vitro RMP susceptibility tests on 3167 M. tuberculosis strains in a high-throughput clinical setting. RESULTS: In the pilot study, rpoB mutation could be detected on 116/132 (87.9%) RMP-resistant strains by dHPLC. In the second phase of the study, 84/3107 (2.7%) clinical M. tuberculosis isolates were RMP-resistant. The sensitivity and specificity of dHPLC in the prediction of RMP resistance were 70/84 (83.3%) and 70/77 (91.0%), respectively. The specificity became 100% when 511 Leu to Pro mutation was excluded from the RMP resistance-related genetic changes. CONCLUSION: In the detection of RMP resistance in a high-throughput laboratory setting, dHPLC has been demonstrated to be rapid, simple, workable, automatable and inexpensive in terms of running costs and the labour involved.

Bacterial Proteins↗
PubMed2005

Prediction of vocational outcome of people with brain injury after rehabilitation: a discriminant analysis.

Due to advancements in emergency evacuation procedures and neurosurgical techniques, more patients with brain injury (BI) can survive cerebral injury and regain a satisfactory degree of recovery through rehabilitation. Their improvement in physical and cognitive functions can facilitate their reintegration into the community, especially their return to work (RTW). Different factors were reported to affect this rate of RTW in previous studies. This retrospective study thus aimed to investigate the role of demographic data, the severity of injury, residual physical deficits, activities of daily living, and cognitive function using a stepwise discriminant function analysis (DFA). Data sets for 79 persons with BI were retrieved so as to identify predictors of their vocational outcomes upon discharge and during a follow-up period. The stepwise DFA revealed that the discharge score on the Disability Rating Scale (DRS), the attention-subtest of the Neurobehavioral Cognitive Status Examination (NCSE) or Cognistat, and pre-morbid occupation were significant predictors that correctly classified 65.8% of the subjects.

Adolescent↗
PubMed2004

Over-expression of Bcl-2 against Pteris semipinnata L-induced apoptosis of human colon cancer cells via a NF-kappa B-related pathway.

Ent-11 alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F), an antitumor component, is a chemical compound isolated from Pteris semipinnata L (PsL), a Chinese traditional herb. We examined whether 5F could affect apoptosis in human colon cancer HT-29 cells, and test whether and how the over-expression of Bcl-2 and Bcl-xL could offset the effect of 5F on cell growth. The result demonstrated that 5F significantly induced apoptosis of HT-29, as shown by MTT assay and DNA fragmentation measurement. Treatment of HT-29 with 5F increased both p38 and iNOS levels, suggesting these two molecules may contribute to the apoptotic effect of 5F. Over-expression of Bcl-2 or Bcl-xL attenuated the increase of p38 and iNOS induced by 5F. The cells with Bcl-2 or Bcl-xL over-expression showed an elevation of nuclear factor kappa B (NF-kappa B) activity, accompanying a significant reduction of 5F-induced apoptosis. Furthermore, inhibition of NF-kappa B by I k B alpha SR, which is a powerful inhibitor of NF-kappa B, restored the ability of 5F to induce apoptosis in the cells transfected with Bcl-2. These data strongly indicated that the apoptotic effect of 5F on HT-29 was closely associated with the activity of NF-kappa B, which was up-regulated by Bcl-2 and Bcl-xL. In conclusion, 5F induced apoptosis in HT-29 cells and this apoptotic effect was associated with the high level of p38 and iNOS expression. The apoptotic effect of 5F could be significantly offset by over-expression of either Bcl-2 or Bcl-xL. Bcl-2, and to the less extent, Bcl-xL, were able to increase the activity of NF-kappa B, which was a known anti-apoptotic molecule in human colon cancer cells.

Apoptosis↗
PubMed2003

Lymphocyte subsets and natural killer cell cytotoxicity after laparoscopically assisted resection of rectosigmoid carcinoma.

BACKGROUND: Laparoscopically assisted resection of colorectal carcinoma is technically feasible and minimally invasive. Postoperative immunosuppression also may be reduced. This study compared the lymphocyte subsets and natural killer (NK) cell cytotoxicity in patients after laparoscopically assisted resection with those after open resection of rectosigmoid carcinoma. METHODS: In this study, 40 patients with rectosigmoid carcinoma, but no evidence of metastasis, were randomized to receive either laparoscopically assisted or conventional open resection of the tumor. Blood was collected before the operation, then 24 h, 72 h, and 8 days after the operation for studies of lymphocyte subsets and NK cell cytotoxicity. RESULTS: The lymphocyte subsets and NK cell cytotoxicity of both groups showed typical suppression after surgery. The suppression of T cell activation and NK-like T cells was significantly less after laparoscopically assisted resection than in after open resection, whereas the difference in other lymphocyte subsets and NK cell cytotoxicity was not significant. CONCLUSION: This study showed that some cellular components of the immune system are less suppressed after laparoscopically assisted than after conventional open resection of rectosigmoid carcinoma. This may have implications for tumor recurrence and long-term patient survival.

Aged↗
PubMed2003

Feasibility study of using air as a contrast medium in MR colonography.

AIM: To evaluate the feasibility of using air as intraluminal contrast medium in magnetic resonance (MR) colonography. MATERIALS AND METHODS: Twenty-two patients underwent MR colonography (MRC) using air before colonoscopy. All patients were imaged in prone and supine positions. Each colon was divided into five segments. Two radiologists reviewed the images for the degree of colonic distension, image quality and colonic lesions. The colonic lesions identified using MR were compared with those identified on colonoscopy. RESULTS: Eight men and 14 women with mean age of 55.5 years were studied. All patients completed the MR examination. One hundred and five out of 110 (95.5%) colonic segments were well distended in both prone and supine positions. Image quality was good in all cases. Colonoscopy detected 16 lesions: three > or = 1 cm, one 7 mm lesion and 12 lesions < or = 5 mm. All lesions 1 cm or larger were detected by MRC. CONCLUSION: MRC using air and the single-shot half-Fourier rapid acquisition with refocused echoes (RARE) technique is feasible. But in this small pilot study, it had low sensitivity for the detection of polyps less than 1 cm in diameter.

Adolescent↗
PubMed2002

Synchronous laparoscopic-assisted right hemicolectomy and right adrenalectomy.

In recent years, minimally invasive surgery has been increasingly employed for the treatment of colorectal and adrenal tumors. We report an 82-year-old woman with synchronous right-sided colonic tumor and right adrenal tumor requiring resection. Preoperative workup showed a 6-cm primary right adrenal tumor with no evidence of invasion to adjacent structures. Laparoscopic removal of the two tumors was achieved with the use of a hand-port device, which assured safe retraction of the liver and meticulous dissection of the adrenal tumor, as well as port site protection during retrieval of the specimens. The whole operation lasted 270 min and our patient made an uneventful recovery.

Adrenal Medulla↗
PubMed2002

Construction of the Chinese University Prognostic Index for hepatocellular carcinoma and comparison with the TNM staging system, the Okuda staging system, and the Cancer of the Liver Italian Program staging system: a study based on 926 patients.

BACKGROUND: The current TNM staging system for patients with hepatocellular carcinoma (HCC) does not include liver function parameters and does not provide a precise prognosis for patients in different risk groups. The objectives of this study were to construct a new prognostic index for patients with hepatocellular carcinoma, the Chinese University Prognostic Index (CUPI), and to compare it with existing staging systems in terms of their ability to classify patients into different risk group. METHODS: From 1996 to 1998, 926 ethnic Chinese patients who were diagnosed with HCC (mainly hepatitis B-associated) at a single institution were recruited prospectively into this study. A multivariate analysis on 19 patient characteristics was performed using a Cox regression model to identify independent prognostic factors. Weights were derived from the regression coefficients of various factors to construct the CUPI. Patients were classified according to different staging systems. Survival curves were plotted with the Kaplan-Meier method and were compared by using a log-rank test. RESULTS: Both the TNM staging system and the Okuda staging system had prognostic significance, but the significance was lower for the Cancer of the Liver Italian Program (CLIP) prognostic score among the patients in the study population. The CUPI was constructed by adding the following factors into the TNM staging system: total bilirubin, ascites, alkaline phosphatase, alpha fetoprotein, and asymptomatic disease on presentation. The new CUPI characterized three risk groups with highly significant differences in survival during the whole period of follow-up (P < 0.00001) and was more discriminant than the other systems. CONCLUSIONS: In the study population of patients with mainly hepatitis B-associated HCC, the CUPI was more discriminant than the TNM staging system, the Okuda staging systems, or the CLIP prognostic score in classifying patients into different risk groups and was better at predicting survival. The CUPI needs to be validated by different cohorts of patients before it can be recommended for general use.

Adult↗
PubMed2001

Predicting mortality and morbidity of patients operated on for perforated peptic ulcers.

HYPOTHESIS: Since the early 1990s, the laparoscopic technique has been increasingly used for the treatment of perforated peptic ulcer. It is important to validate a risk scoring system that can stratify patients into various risk groups before comparing the treatment outcome of laparoscopic repair against that of conventional open surgery. The scoring system should be able to predict the likelihood of mortality and morbidity. Boey score and APACHE II (Acute Physiology and Chronic Health Evaluation II) score may be of use in patient stratification. DESIGN: Retrospective review of relevant case notes by one reviewer. SETTING: A teaching hospital treating 0. 5 million to 1 million patients during the study period. PATIENTS: Patients operated on for perforated peptic ulcer between January 1989 and December 1998. Patients treated conservatively were excluded. MAIN OUTCOME MEASURES: Mortality and postoperative complications (morbidity). RESULTS: A total of 436 patients (365 male and 71 female) with a mean +/- SD age of 51.5 +/- 18.3 years (range, 14-92 years) were studied. Duodenal perforation accounted for 344 (78.9%) of 436 cases. The mortality rate was 7.8% (34/436), and 89 patients had postoperative complications. Multivariate analysis demonstrated that only the APACHE II score predicted both mortality and morbidity. Although the Boey score predicted mortality, it failed to predict morbidity. However, the Boey score predicted the chance of conversion in patients undergoing laparoscopic repair. CONCLUSIONS: The APACHE II score may be a useful tool for stratifying patients into various risk groups, and the Boey score might select appropriate patients for laparoscopic repair.

APACHE↗
PubMed2001

Selection of patients for laparoscopic repair of perforated peptic ulcer.

BACKGROUND: Although randomized and non-randomized studies have evaluated the safety of laparoscopic repair for perforated peptic ulcer, no definite guidelines have been published on selection of patients for laparoscopic repair. This cohort study aimed to define patients who may not benefit from laparoscopic techniques. METHODS: The data from 374 consecutive patients with perforated peptic ulcer treated by simple repair were collected prospectively and analysed. RESULTS: From January 1992 to December 1998, 219 patients were treated by open suture repair, 109 by laparoscopic sutureless (fibrin glue) repair and 46 by laparoscopic suture repair. The overall leak rate after laparoscopic suture and sutureless repair was 6 and 16 per cent respectively. Leakage was noted to be associated with a significantly higher rate of wound infection, intra-abdominal abscess formation, prolonged ileus (P < 0.001) and longer hospital stay (11 versus 5 days; P < 0.001). Multivariate analysis demonstrated that Acute Physiology and Chronic Health Evaluation (APACHE) II score on admission predicted the likelihood of a leak after laparoscopic fibrin glue repair (P = 0.006). CONCLUSION: APACHE II score may be a useful index for selecting patients for laparoscopic fibrin glue repair.

APACHE↗
PubMed2000

Laparoscopic-assisted abdominoperineal resection for low rectal adenocarcinoma.

BACKGROUND: Laparoscopic-assisted resection for colorectal lesions is feasible, but most reported series are heterogeneous and noncomparative. The aim of this study was to investigate whether laparoscopic-assisted resection was better than open abdominoperineal resection for low rectal adenocarcinoma. METHODS: Twenty-five (study group) of 59 consecutive patients who were considered suitable were selected for laparoscopic-assisted abdominoperineal resection based on the availability of informed consent, laparoscopic instruments, and experienced surgeons. The results in these patients were compared with the other 34 patients operated on by the open method (control group). RESULTS: The median follow-up times for the study and control groups were 30.1 and 28.3 months, respectively. The operation time was significantly longer (t-test, p < 0.001), while operative blood loss (Mann-Whitney U test, p = 0.02), postoperative analgesic requirement (Mann-Whitney U test, p = 0.02), time to resume normal diet (Mann-Whitney U test, p = 0.04), and total hospital stay (Mann-Whitney U test, p = 0.02) were significantly less in the study than in the control group. The oncological clearance, complication rate, disease-free interval, and survival were comparable in the two groups. CONCLUSIONS: Laparoscopic-assisted abdominoperineal resection allowed earlier postoperative recovery, with equal oncological clearance, morbidity, mortality, disease-free interval, and survival.

Adenocarcinoma↗
PubMed2000

Systemic cytokine response after laparoscopic-assisted resection of rectosigmoid carcinoma: A prospective randomized trial.

OBJECTIVE: To compare the systemic cytokine response in patients after laparoscopic-assisted resection with those after open resection of rectosigmoid carcinoma. SUMMARY BACKGROUND DATA: Laparoscopic resection of colorectal carcinoma is technically feasible, but objective evidence of its benefit is scarce. Systemic cytokines are accepted as markers of postoperative tissue trauma and mediators of the host immune response. METHODS: Thirty-four patients with rectosigmoid carcinoma, without evidence of metastatic disease and suitable for laparoscopic resection, were randomized to undergo either laparoscopic (n = 17) or conventional open (n = 17) resection of the tumor. Clinical parameters were recorded. Sera were collected before surgery and at appropriate time points afterward and assayed for interleukin-1beta, tumor necrosis factor-alpha, interleukin-6, and C-reactive protein. The primary end points were the cytokine and C-reactive protein levels. Data were analyzed by intention to treat. RESULTS: The demographic data of the two groups were comparable. The clinical outcome of both groups was satisfactory, with no surgical deaths and a reasonable complication rate. Both interleukin-1beta and interleukin-6 levels peaked 2 hours after surgery, with the responses in the laparoscopic group significantly less than those in the open group. C-reactive protein levels peaked at 48 hours, and the difference was also statistically significant. Levels of tumor necrosis factor-alpha were not elevated after surgery, and there was no difference between the groups. CONCLUSIONS: Tissue trauma, as reflected by systemic cytokine response, was less after laparoscopic resection than after open resection of rectosigmoid carcinoma. The difference in the systemic cytokine response may have implications on the long-term survival.

Aged↗
PubMed2000

Cholangiographic features in the diagnosis and management of obstructive icteric type hepatocellular carcinoma.

In 11 years and 3 months, 2,037 patients with HCC were seen and 48 patients (2.4%) were diagnosed to have obstructive icteric type HCC. Five patients were terminally ill and were not investigated further. Forty three patients were initially investigated by endoscopic retrograde cholangiography (ERC) or percutaneous transhepatic cholangiogram (PTC) and classified as having obstructive icteric type 1, 2, or 3 HCC based on the cholangiographic findings. The obstruction in type 1 HCC was due to intraluminal tumour casts and/or tumour fragments obstructing the hepatic ductal confluence or common bile duct, while intraluminal blood clots, from haemobilia, filling the biliary tree was the cause in type 2 HCC. The pathology in type 3 HCC was extraluminal obstruction by extensive tumour encasement of the intra-hepatic biliary ductal system and/or extrinsic compression of the hepatic and common bile ducts by tumour(s) and/or malignant lymph nodes. At the initial ERC/PTC, 10 patients (5 resected, 50%) had obstructive icteric type 1 and 23 patients (0 resected) had obstructive icteric type 3 HCC. Of the 10 patients initially classified according to cholangiography to have obstructive icteric type 2 HCC, subsequent investigations revealed that 6 patients had type 1 HCC (4 resectable,67%) and 4 patients had type 3 HCC (0 resectable). The classification of the obstructive icteric type HCC into types 1, 2, and 3, based on the initial cholangiographic appearances has simplified and rationalized our management strategy for this condition.

Algorithms↗
PubMed2000

The use of liposucker for spleen retrieval after laparoscopic splenectomy.

The retrieval of spleen after laparoscopic splenectomy has long been a problem. Frequently, it is necessary to extend the wound for retrieving the spleen intact and to prevent potential spillage of splenic tissue into the peritoneal cavity. We describe the application of the liposuction unit to remove the spleen piecemeal after laparoscopic splenectomy. We have found this technique easy to apply and safe, without the necessity of excessive wound extension, while preserving splenic tissue for histologic examination.

Adult↗
PubMed1999

Spontaneous rupture of hepatocellular carcinoma: conservative management and selective intervention.

HYPOTHESIS: A conservative approach using selective intervention is better than an aggressive approach using nonselective intervention for ruptured hepatocellular carcinoma. DESIGN: Nonrandomized controlled trial. SETTING: A university hospital. PATIENTS AND INTERVENTIONS: From 1984 to 1990, an aggressive approach was adopted in which 29 and 8 of a total of 40 patients underwent surgical intervention or attempted transarterial embolization (TAE), respectively. From 1991 to 1997, a more conservative approach was used. The initial treatment for 72 patients was conservative with close monitoring. Additional hemostatic procedures consisting of TAE (n = 13) or surgical intervention (n = 9) were given, depending on the clinical progress, disease status, and liver function of the patients. MAIN OUTCOME MEASURES: In-hospital mortality, survival. RESULTS: In-hospital mortality rate was 62% (25 of 40 patients) in the first period and 51% (37 of 72 patients) in the second period. The respective median survival times were 7 and 12 days. If 36 patients with end-stage malignant neoplasms were excluded, the in-hospital mortality rate became 60% (18 of 30 patients) in the first period and 35% (16 of 46 patients) in the second period (P = .03, chi2 test). The respective median survival times became 8 and 72 days (P = .02, log rank test). In the second period, 7 (54%) of 13 patients who underwent TAE and 1 (11%) of 9 patients who underwent surgical intervention died within the same hospital admission (P = .07, Fisher exact test). CONCLUSIONS: Selective intervention was cost-effective and gave better results than an aggressive approach. When intervention was indicated for hemostasis, surgery seemed better than TAE although the difference was not statistically significant.

Carcinoma, Hepatocellular↗