Biomedical subjects

A Chang

Publications and source records attributed to A Chang.

At least 19 recordsLinked to original sources

PubMed2005

The impact of past alcohol use on treatment response rates in patients with chronic hepatitis C.

BACKGROUND: Studies have shown that past alcohol consumption reduces response rates in patients with chronic hepatitis C treated with interferon monotherapy. AIM: To clarify the importance of alcohol consumption on response rates in patients undergoing treatment with pegylated interferon and ribavirin. METHODS: In a single centre, prospective study, median daily alcohol consumption (determined by previously validated method) and quartiles of alcohol consumption were calculated. Univariate and binary logistic regression analyses were performed using treatment response status as the dependent variable. RESULTS: Overall, in an intention-to-treat analysis, 34 of 115 patients (30%) responded to treatment. In univariate analysis, black patients, especially those with hepatitis C virus genotype 1, high viral load and low alanine aminotransferase were significantly less likely to respond. Predictors of response by regression analysis included alcohol <30 g/day (OR=3.02, 95% CI: 1.02-8.93; P=0.04), non-genotype 1 status (OR=1.98, 95% CI: 1.03-3.80; P=0.04) and non-black race (OR=2.79, 95% CI: 1.33-5.85; P=0.006). CONCLUSIONS: Median daily alcohol use >30 g/day is associated with failure to respond to pegylated interferon and ribavirin for treatment of hepatitis C. Past alcohol use should be evaluated when considering treatment for hepatitis C.

Adult↗

PubMed2005

Technical skills errors in laparoscopic cholecystectomy by expert surgeons.

BACKGROUND: Performing laparoscopic surgery involves a complex cascade of cognitive skills, which may inherently have a constant technical error rate. We assess generic and specific minor and major error rates in laparoscopic cholecystectomies (LCs) performed by consultant surgeons. METHODS: Checklists of generic (11) and specific technical minor (six) and major events (eight) were devised for LCs. Two experienced surgeons assessed each full-length operation blindly and independently. RESULTS: A total of 37 LCs were performed by eight consultants. There were no major intraoperative or postoperative complications. Mean inter-rater reliability was kappa = 0.91 (range 0.80-0.98) for each of the error categories. Error rates were generic (27/407) 6.6%, minor (59/222) 26.6%, and major (8/296) 2.7%, respectively. There was a significant statistical difference between the minor error group and the other groups, p <or= 0.05. CONCLUSIONS: Performing laparoscopic surgery may always have a background technical error rate. Our present study demonstrates a migration of surgical technical errors in expert laparoscopic surgeons. The surgeons migrate technically when they execute a high rate of procedure-specific minor errors. However, when it comes to the major fundamental aspects of the operation, they dynamically adapt and migrate away from performing major technical errors. We aim to continue the study to increase cases, assess trainees as well, and also explore other factors that may affect the surgeon when executing surgical technical tasks.

Adult↗

PubMed2005

Fetal growth velocities in Hong Kong Chinese infants.

Few studies have investigated the velocities of fetal growth. The aim of the present study was to determine the pattern of 'fetal' growth velocities in a Chinese population. The gestation-specific measurements of the body weight, body length and head circumference in a representative sample of 5,045 male and 4,484 female newborns delivered between 26 and 42 weeks of gestation at 12 hospitals in Hong Kong were obtained. Peak growth velocity occurred before 30 weeks of gestation for head circumference, at week 30 for length and at week 30 for weight. When compared with data obtained from a French population, a significant difference in the growth velocity for body weight was observed below 32 weeks between French and Chinese infants, suggesting an ethnic difference in fetal growth of this parameter.

Anthropometry↗

PubMed2005

Normative data of penile length for term Chinese newborns.

Careful examination and assessment of penile length in the newborn is important because micropenis is associated with hypothalamic disorders. This prospective cross-sectional study was designed to establish the norm of penile length for term Hong Kong Chinese newborns. 4,628 full-term healthy male newborns were enrolled in the study. Penile length was measured from pubic ramus to the tip of the glans penis by placing the end of a straight edge ruler against the pubic ramus. A gestation-associated graph of 3rd, 10th, 25th, 50th, 75th, 90th and 97th centiles for the penile length was created. The penile length was significantly correlated with gestational age, birth weight and body length. When compared with published data for other populations, Hong Kong newborns have significantly shorter penile length. The norm of the penile length is useful in diagnostic and therapeutics for the ethnic Chinese male newborns.

Asian People↗

PubMed2004

Bimodal assessment of laparoscopic suturing skills: construct and concurrent validity.

BACKGROUND: The assessment of technical skills should provide objective feedback and judge suitability of progress during training. The aim of this study was to validate two objective assessment techniques for laparoscopic suturing and demonstrate a correlation between them. METHODS: Six experts, seven surgeons skilled in laparoscopic suturing, and 13 with no laparoscopic suturing skills were asked to place two or three intracorporeal sutures on a synthetic suture pad. The latter group was given video-based instructions prior to the execution of the sutures. Ergonomic conditions were standardized for all subjects. The procedures were recorded on videotape and two blinded observers rated the first suture of each subject on a 29-point checklist. A motion analysis system, Imperial College Surgical Assessment Device, was used to assess psychomotor skills. RESULTS: There was a significant difference in the time taken (p = 0.000) and total path length (p = 0.000) per suture across the groups. There were also a significant difference in the total checklist score (p = 0.000) and its individual categories. The was a strong correlation between the total path length and the total checklist score (coefficient, 0.78; p < 0.001). CONCLUSIONS: A combination of the motion analysis system and the checklist would make the process of formative feedback during the learning of intracorporeal suturing objective and comprehensive.

Clinical Competence↗

PubMed2004

Inhaled cromones for prolonged non-specific cough in children.

BACKGROUND: Non-specific cough is defined as non-productive cough in the absence of identifiable respiratory disease or known aetiology. It is commonly seen in paediatric practice. These children are treated with a variety of therapies including inhaled cromones. OBJECTIVES: To determine the efficacy of inhaled cromones in the management of prolonged non-specific cough in children. SEARCH STRATEGY: The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register Collaboration and Cochrane Airways Group, MEDLINE and EMBASE databases were searched. Australian representative of the relevant pharmaceutical company was contacted. The latest searches were performed in October 2003. SELECTION CRITERIA: All randomised controlled trials comparing inhaled cromones with a placebo medication. DATA COLLECTION AND ANALYSIS: Results of searches were reviewed against pre-determined criteria for inclusion. No eligible trials were identified and thus no data were available for analysis. One single arm open trial in children and one small randomised controlled trial in adults were reported. MAIN RESULTS: No randomised-controlled trials that examined the efficacy of inhaled cromones in the management of prolonged non-specific cough in children were found. In the non randomised trials above, a significant effect was seen within two weeks of therapy. REVIEWERS' CONCLUSIONS: There is currently an absence of evidence to support the routine use of inhaled cromones for symptomatic control of non-specific cough in children. Further research examining the effects of this intervention is needed.

Administration, Inhalation↗

PubMed2004

Auricular anthropometry of Hong Kong Chinese babies.

OBJECTIVES: To provide a database of the auricular measurements of Chinese infants born in Hong Kong. DESIGN: Prospective cross-sectional study. SETTING AND SAMPLE POPULATION: A total of 2384 healthy singleton, born consecutively at the Prince of Wales Hospital and the Union Hospital from October 1998 to September 2000, were included in the study. The range of gestation was 33-42 weeks. MEASUREMENTS AND RESULTS: Measurements included ear width (EW), ear length (EL) and ear position (EP). The data show generally higher values for males in the parameters measured. When compared with previously published data for Caucasian and Jordanian term babies, Chinese babies have shorter EL. The ears were within normal position in nearly all our infants. CONCLUSION: The human ear appears to grow in a remarkably constant fashion. This study establishes the first set of gestational age-specific standard of the ear parameters for Chinese new-borns, potentially enabling early syndromal diagnosis. There are significant inter-racial differences in these ear parameters.

Asian People↗

PubMed2004

Australasian CD34+ quality assurance program and rationale for the clinical utility of the single-platform method for CD34+ cell enumeration.

BACKGROUND: Enumeration of CD34(+) cells should be accurate and comparable between institutions, particularly when making clinical decisions, evaluating data, and in clinical trials. An Australasian CD34(+) quality assurance program (QAP) has been established to compare CD34(+) cell results and method (Part 1). Unexpected variation in WBCCs led to Part 2 of this report. METHODS: Part 1: Methods reagents and results were evaluated for 12 QAP samples analyzed by 36-43 centers. Part 2: The effects of different anticoagulants on WBCC of 12 peripheral blood samples (PBs) were compared using three cell counters. To test the validity of applying the conclusions to clinical samples, the WBCCs of leukapheresed products and BM harvest were also compared. RESULTS: Part 1: In some samples, WBCCs determined by certain cell-counter groups were significantly different. Results for percentage of CD34(+) and CD34(+)/microL suggest that standardization on the lyse-no-wash and single platform (SP) method reduces variation of results between institutions. Part 2: Using different counters, PB WBCC in ACD-A showed greater variation than the same PB in EDTA. For PB in different anticoagulants, the extent of difference in WBCC for the same PB is dependent on the counter used. DISCUSSION: This CD34 QAP has identified ACD-A as an additional factor that contributes to the disparate WBCCs, which may further compromise the accuracy of CD34(+) cell counts obtained by the dual platform (DP) method, especially for leukapheresed products. In order to achieve greater accuracy within individual institutions, as well as permitting more reliable inter-institutional comparisons, our data supports the adoption of the SP as the standard method for CD34(+) cell enumeration.

Anticoagulants↗

PubMed2004

von Willebrand disease: laboratory aspects of diagnosis and treatment.

von Willebrand disease is the most common inherited bleeding disorder in humans. VWD can be classified into three major types, designated Types 1, 2 and 3; Type 2 can be further separated into subtypes 2A, 2B, 2M and 2N. The diagnosis of VWD requires a personal and family history of bleeding and confirmation by laboratory analysis. Although Types 2 and 3 are relatively straightforward to diagnose, there may be a risk of overdiagnosis of Type 1 because of an overlap within the normal range. We also report on the clinical profile and diagnosis of VWD in a South American cohort of patients and on the in vitro characteristics of some factor concentrates available for treatment of VWD.

Adolescent↗

PubMed2004

Multiple endocrine neoplasia type 2B in a Chinese patient.

Multiple endocrine neoplasia type 2B syndrome is rarely reported in Chinese patients. A 25-year-old Chinese male presented with full-blown clinical features of this syndrome, including bilateral phaeochromocytomas, medullary thyroid carcinoma, and characteristic phenotypic features. One-stage surgical treatment was performed and subsequent genetic analysis confirmed a point mutation at codon 918 in exon 16 of the RET proto-oncogene. The mutation was arising de novo as there was no corresponding mutation found in both his parents or younger sister. Data published to date suggest there is no difference in the genetic and pathophysiologic basis, nor clinical characteristics of multiple endocrine neoplasia type 2B in Chinese patients. As the disease can be lethal, early diagnosis by prompt recognition of the characteristic phenotypic features followed by surgical treatment should improve the outcome. Family screening is essential to identify at-risk family members for prophylactic treatment.

Adrenalectomy↗

PubMed2003

Validity and reliability of a virtual reality upper gastrointestinal simulator and cross validation using structured assessment of individual performance with video playback.

BACKGROUND: This study aims to evaluate the ability of an upper gastrointestinal virtual reality simulator to assess skills in endoscopy, and to validate its metrics using a video-endoscopic (VES) technique. METHODS: The 32 participants in this study were requested to undertake two cases on the simulator (Simbionix, Israel). Each module was repeated twice. The simulator's metrics of performance were used for analysis. two blinded observers rated performance watching the simulator's playback feature. RESULTS: There were 11 novices (group 1), 11 trainees with intermediate experience (10-50 procedures, group 2), and 10 experienced endoscopists (>200 procedures, group 3). There was a significant difference in the total time required to perform the procedure (p < 0.001), percentage of mucosa visualized (p < 0.001), percentage of pathologies visualized (p < 0.001), and number of inappropriate retroflexions (p = 0.015) across the three groups. The reliability of assessment on the simulator was greater than 0.80 for all parameters. The VES assessment also was able to discriminate performance across the groups (p < 0.001). There was a significant correlation between the VES score and the percentage of mucosa visualized (rho = 0.60; p < 0.001). CONCLUSIONS: The upper gastrointestinal simulator may be a useful tool for determining whether a trainee has achieved a desired level of competence in endoscopy. The next step will be to validate the VES score in real procedures.

Endoscopy, Gastrointestinal↗

PubMed2003

Percutaneous arterial closure in peripheral vascular disease: a prospective randomized evaluation of the Perclose device.

BACKGROUND: Patients with peripheral vascular disease have been excluded from initial studies of percutaneous suture-mediated closure devices (SMCD) despite representing a significant proportion of those requiring endovascular intervention. We sought to determine whether these devices could be safely used in patients with peripheral vascular disease. METHODS: Patients were stratified into two groups and five subgroups on the basis of indication for arteriography, and they were prospectively randomized at the end of the procedure to receive either the SMCD or manual compression. Ankle-brachial index was determined and duplex ultrasound scanning of the accessed femoral artery was performed, before and after the procedure. Ultrasound data included peak systolic velocity, minimum intraluminal vessel diameter, and presence or absence of calcified plaque. Time to hemostasis, ambulation, and discharge were recorded, and major or minor complications were noted. RESULTS: Of 102 patients included in the study, 52 patients were randomized to receive the SMCD. There was no difference in ankle-brachial index, minimum intraluminal vessel diameter, or peak systolic velocity in the accessed vessel after closure with SMCD or manual compression. Time to hemostasis, ambulation, and discharge was significantly less in the SMCD group (P =.001). Presence of calcified plaque was not associated with complications (P =.146). In the SMCD group, hemostasis was achieved with 49 of 52 devices (94.2%). There were six complications (5.9%), two of which were major and required operative intervention. All complications were hemorrhagic and not occlusive. There was no difference in overall complication rate between SMCD (7.7%) and manual compression (4.0%) groups (P =.678). No infection was noted in any of the 102 patients. CONCLUSIONS: Suture-mediated percutaneous arterial closure can be safely performed in patients with peripheral vascular disease, even in the presence of calcified plaque. This closure technique enables shorter time to hemostasis, ambulation, and hospital discharge. There are observed differences in minor, but not major, complication rates for MC versus percutaneous arterial closure in patients with peripheral vascular disease, but these differences did not achieve statistical significance in this small series.

Aged↗

PubMed2003

Facial anthropometry of Hong Kong Chinese babies.

OBJECTIVES: To provide a database of the craniofacial measurements of Chinese infants born in Hong Kong. DESIGN: Prospective cross-sectional study. SETTING AND SAMPLE POPULATION: A total of 2371 healthy singleton, born consecutively at the Prince of Wales Hospital and the Union Hospital from June 1998 to June 2000, were included in the study. The range of gestation was 33-42 weeks. MEASUREMENTS AND RESULTS: Measurements included facial width (FW), facial height (FH), nasal length (NL), nasal width (NW), and length of the philtrum (PhilL). The facial, nasal, nasofacial and nasozygomatic indices were derived. The data show generally higher values for males in the parameters measured. The various indices remained remarkably constant and did not vary significantly between the two genders or with gestation. When compared with previously published data for white people term babies, Chinese babies have similar NW but shorter philtrum length. CONCLUSION: The human face appears to grow in a remarkably constant fashion as defined by the various indices of facial proportions. This study establishes the first set of gestational age-specific standard of such craniofacial parameters for Chinese new-borns, potentially enabling early syndromal diagnosis. There are significant inter-racial differences in these craniofacial parameters.

Asian People↗

PubMed2003

Craniofacial anthropometry of Hong Kong Chinese babies: the eye.

OBJECTIVES: To provide a database of the canthal measurements of Chinese infants born in Hong Kong. DESIGN: Prospective cross-sectional study. SETTING AND SAMPLE POPULATION: A total of 2,371 healthy singleton, born consecutively at the Prince of Wales Hospital and the Union Hospital from June 1998 to June 2000, were included in the study. The range of gestation was 33-42 weeks. MEASUREMENTS AND RESULTS: Canthal parameters were measured and included the outer canthal distance (OCD), intercanthal distance (ICD) and palpebral fissure length (PFL). The data generally show higher values for males in the parameters measured. The measurements were also compared with data published overseas. PFL and OCD were significantly larger in Hong Kong Chinese newborn babies, whereas ICD was smaller. CONCLUSION: This study establishes the first set of gestational age-specific standard of such craniofacial parameters for Chinese newborn babies, potentially enabling early syndromal diagnosis. There are significant inter-racial differences in these canthal parameters.

Algorithms↗

PubMed2003

Updated gestational age specific birth weight, crown-heel length, and head circumference of Chinese newborns.

OBJECTIVE: To construct gestation specific standards of birth weight, crown-heel length, and head circumference of Chinese infants. DESIGN: A prospective cross sectional population study. METHODS: The birth weight, crown-heel length, and head circumference were prospectively measured using standard equipment in newborns delivered at 24-42 weeks gestation in the maternity units of 10 public hospitals and two private hospitals in Hong Kong. The findings were used to construct gestation specific standards of these variables. The LMS method using maximum penalised likelihood was used to perform model fitting. The results were compared with those obtained from a cohort of infants born in the same locality between 1982 and 1986. RESULTS: From October 1998 to September 2000, a total of 10 032 infants were measured, representing 9.6% of the total deliveries in Hong Kong during that period. An extra 307 infants with gestation < or = 35 weeks were recruited from October 2000 to June 2001. Each of the three variables showed a normal distribution at each gestational week. Gestation specific reference standards for each variable were constructed for male and female infants separately. Comparison with the 1982-1986 cohort showed a significant secular trend to increased birth weight. The trend was small, but significant, for crown-heel length and head circumference. CONCLUSION: These growth standards will provide useful references for the care of newborns of ethnic Chinese origin. These standards, especially that for birth weight, should be updated regularly.

Birth Weight↗

PubMed2002

Human kallikrein gene 13 (KLK13) expression by quantitative RT-PCR: an independent indicator of favourable prognosis in breast cancer.

Kallikreins are a group of serine proteases with diverse physiological functions. KLK13 (previously known as KLK-L4) is a novel kallikrein gene located on chromosome 19q13.4 and shares a high degree of homology with other kallikrein family members. Many kallikrein genes were found to be differentially expressed in various malignancies, and their regulation is controlled by steroid hormones in prostate and breast cancer cell lines. We studied the expression of KLK13 by quantitative reverse transcriptase-polymerase chain reaction in 173 patients with epithelial breast carcinoma. An optimal cutoff point equal to the 40th percentile was defined, based on the ability of KLK13 to predict disease-free survival. KLK13 values were then associated with other established prognostic factors and with disease-free survival and overall survival. Higher positivity for KLK13 expression was found in older, oestrogen receptor positive patients. In univariate analysis, KLK13 expression is a significant predictor of improved disease-free survival and overall survival (P<0.001 and P=0.009, respectively). Cox multivariate analysis indicated that KLK13 was an independent prognostic variable in the subgroups of patients with Grade I-II tumours and in patients who were oestrogen receptor and progesterone receptor positive, and node positive. Hazard ratios derived from Cox analysis, related to disease-free survival and overall survival were 0.22 (P=0.001) and 0.24 (P=0.008), respectively, for the Grade I-II group; 0.36 (P=0.008) and 0.44 (P=0.038), respectively, for the node positive group and 0.36 (P=0.008) and 0.18 (P=0.008), respectively, for the oestrogen receptor positive group. The adjusted hazard ratio for progesterone receptor positive patients for disease-free survival was 0.25 (P=0.012). For patients in the node positive and oestrogen receptor positive subgroup (n=51) the adjusted hazard ratio was 0.25 (P=0.006) and for the node positive and progesterone receptor positive subgroup (n=46) the hazard ratio was 0.24 (P=0.008). Taken together, these data suggest that higher KLK13 expression in these subgroups of breast cancer patients is associated with an approximately 55 to 80% reduction in the risk of relapse or death. We conclude that KLK13 expression, as assessed by quantitative reverse transcriptase-polymerase chain reaction, is an independent favourable prognostic marker for breast carcinoma.

Adult↗

PubMed2002

Practice distribution in procedural skills training: a randomized controlled trial.

BACKGROUND: "Massed" and "distributed" practice are important concepts in the acquisition of fine motor skills, and may be important in training in procedural skills. METHODS: A total of 41 novice subjects were recruited and randomized to three groups to receive training on the MIST VR surgical trainer. There were 14 subjects in each of groups A and B and 13 subjects in group C. Training comprised 20 min of massed practice for group A, 20 min of distributed practice in 5 min blocks for group B, and 15 min of distributed practice in 5-min blocks for group C. Following the training period, all groups had a 5-min rest period, followed by a 5-min retention test. Comparisons were made between groups A and B, and groups A and C. RESULTS: There was a statistically significant difference between groups A and B (p = 0.023) on the retention test, with group B performing better. The increment between the groups was 19% for the overall score on MIST VR. There were also significant differences in the time taken to complete the task during the training phase (p = 0.023, training blocks 3 and 4). Graphical representation suggests no effect between groups A and C, and statistical analysis confirms that the observed difference in median score is not significant. CONCLUSION: This study demonstrates a benefit for distributed practice over massed practice in learning laparoscopic surgical skills on the MIST VR surgical trainer. This finding has potential implications for skills training in all areas of medicine.

Adult↗

PubMed2002

Varicose veins possess greater quantities of MMP-1 than normal veins and demonstrate regional variation in MMP-1 and MMP-13.

BACKGROUND: Studies have reported that structural proteins such as elastin and collagen are decreased in varicose veins compared to normal controls. We hypothesized that the changes observed in varicose vein wall composition may be related to alterations in extracellular matrix remodeling proteins, such as the matrix metalloproteases and serine proteases. In addition we hypothesized that there may be regional variation in the expression of these enzymes within the leg. PATIENTS AND MATERIALS: One-centimeter segments of the proximal and distal greater saphenous vein (GSV) were obtained from patients undergoing ligation and stripping for venous insufficiency (vv) (n = 15) or GSV harvest in conjunction with coronary artery bypass grafting (CABG) (n = 7). All vv patients had incompetence of the GSV by color flow duplex. Vein specimens were examined for MMP-1, 3, and 13, tryptase, and GAPDH mRNA using semiquantitative RT-PCR analysis. Quantification of MMP-1 and 13 (active/latent forms) and tryptase was performed using Western blot analysis. Western blots were analyzed using scanning densitometry and standardized to normal controls and values expressed as the median densitometric index (D.I.). Nonparametric statistical methods (Wilcoxan signed rank test and Mann-Whitney U test) were used for analysis. RESULTS: We were able to amplify MMP-1, MMP-13, and tryptase mRNA from both proximal and distal segments of all greater saphenous veins studied. MMP-3 mRNA, however, was not found in either segment of any of the veins examined. A semiquantitative analysis of RT-PCR products comparing the ratio of MMP-1, MMP-13, or tryptase mRNA to GAPDH mRNA showed no difference between cases and controls nor proximal vs distal vein segments. Western blot analysis revealed larger quantities of MMP-1 in varicose veins than in nondiseased veins from CABG patients (48.0 +/- 36.7 D.I. vs 12.5 +/- 6.8 D.I., P = 0.036). Investigation into the regional variation of proteases revealed lower amounts of MMP-1 in distal than in proximal vein segments (37.9 +/- 35.0 D.I. vs 44.1 +/- 41.6 D.I., P = 0.01). Similarly, we found significantly less MMP-13 in distal segments of varicose veins than in proximal segments (152.8 +/- 130.0 D.I. vs 206.7 +/- 173.3 D.I., P = 0.006). CONCLUSIONS: This study found that MMP-1 protein is increased in varicose veins when compared to controls despite no differences in mRNA expression. In addition we found that there is regional variation of MMP-1 and MMP-13 in diseased varicose veins. Lower leg veins have significantly reduced amounts of these proteolytic enzymes when compared to veins of the upper thigh. These data suggest that posttranscriptional regulatory controls could be responsible for the observed differences.

Adult↗