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Biomedical subjects

C M Wong

Publications and source records attributed to C M Wong.

At least 73 records · Page 4Linked to original sources
PubMed1997

An audit of the safety of an acute pain service.

We audited and analysed the adverse effects and safety of postoperative pain management on 2509 consecutive patients under care of the Acute Pain Service at a tertiary referral teaching hospital over a 32-month period. Our standard respiratory monitoring consisted of continuous pulse oximetry, hourly respiratory rate counting, sedation scoring and intermittent arterial blood gas sampling. This protocol was reliable and detected six episodes of bradypnoea, 13 of hypercapnia and 23 of oxygen desaturation occurring in 39 patients (1.8% of all spontaneously breathing patients). Two patients required naloxone injection and none had long-term sequelae. Hypotension due to epidural bupivacaine 0.0625% and fentanyl 3.3 micrograms.ml-1 infusion occurred in four patients (1.2%), all with a sensory block higher than T5. They readily responded to fluid infusion and ephedrine (two patients). Postoperative nausea or vomiting occurred in 723 (28.8%) and 380 (15.1%) patients, respectively. Odds ratio analysis showed that the risk factors for postoperative nausea and vomiting were: female gender, gynaecological operations, nongeriatric patients and systemic analgesia. Postoperative nausea and vomiting decreased analgesic efficacy by discouraging the use of patient-controlled analgesia and was regarded as equally distressing as pain. Other side-effects included: pruritus in 182 patients; dizziness in 333 and lower limb weakness in 73 (21.2% of patients receiving epidural local anaesthetics). It is concluded that a standard monitoring and management protocol, an experienced nursing team and reliable Acute Pain Service coverage is mandatory for the safe use of modern analgesic techniques.

Aged↗
PubMed1997

Predicting stress in first year medical students: a longitudinal study.

While there is ample documentation that medical training is stressful, less is known about predictive variables that might identify students who have the most difficulty in managing stress during medical training. Depression and anxiety in first year medical students were investigated in a longitudinal design. One-hundred and twenty-one medical students (81% of the class) were surveyed. The first survey took place immediately prior to the beginning of medical training (wave 1); the second survey was approximately 8 months after the beginning of classes (wave 2). Medical students who began their first year with relatively low 'A' level grades, high ratings of state anxiety and depression, high trait anxiety and low dispositional optimism, and reliance on avoidant coping strategies were found to be at higher risk for developing depression and anxiety symptoms at wave 2. Students reported increased concern about curriculum and environment, personal competence and endurance, and time to have a life outside medical school at wave 2, compared to their reports at wave 1. Increase in concerns correlated with an increase in depression and anxiety. At both surveys, use of avoidant coping strategies resulted in increased depression and anxiety; at wave 2, active coping and positive reinterpretation resulted in decreased depression and anxiety. These findings suggest characteristics of vulnerable students who might be identified early in their first year and provided with additional support. Educating students to expect an increase in concerns about environment and personal ability to manage the academic load might make these concerns less overwhelming. In addition, information about effective coping strategies (i.e. active coping efforts) and ineffective means of dealing with stress (avoidant coping efforts) might be helpful in preventing distress.

Adaptation, Psychological↗
PubMed1997

A comprehensive study of smoking in primary school children in Hong Kong: implications for prevention.

STUDY OBJECTIVE: To identify factors associated with smoking behaviour in primary school children in Hong Kong. DESIGN: A cross sectional survey in which both children and parents completed questionnaires. The main outcome measure was the smoking status of the children; and risk factors (knowledge of and attitude to smoking and demographic and socioeconomic background) were identified as predictors of ever/never smoking. SETTING AND SUBJECTS: Altogether 9598 primary school children, aged 8-13 years, and attending 27 schools from two districts in Hong Kong participated. MAIN RESULTS: The prevalence of ever-smoking was 12% (1119)-15% (760) in boys and 7% (359) in girls. It ranged from 3% in 8 year old girls to 52% in 13 year old boys. The factors associated with ever-smoking included the following: being a boy (adjusted odds ratio 2.21; 95% confidence interval 1.89, 2.59), increasing age per year (1.48; 1.40, 1.57), living in Kwai Tsing district (1.29; 1.10, 1.50), having one or more smokers at home (2.07; 1.78, 2.39), and having a father who was not working (1.41; 1.19, 1.67). Children who were ever-smokers had both seen and approved of their friends' smoking (8.79; 5.33, 14.50), had a more positive attitude towards smoking (3.35; 2.21, 5.09), and were more successful in recognising cigarette brand names and logos (1.67; 1.42, 1.96), but they lacked confidence (1.78; 1.32, 2.39). CONCLUSIONS: The influences on child smoking are multifactorial and programmes in Hong Kong are falling to curb them. The control of these risk factors must be incorporated in the smoking prevention policy of Hong Kong and supported by future enforced legislation.

Adolescent↗
PubMed1997

Femtosecond dynamics of electrons on surfaces and at interfaces.

Two-photon photoemission is a promising new technique that has been developed for the study of electron dynamics at interfaces. A femtosecond laser is used to both create an excited electronic distribution at the surface and eject the distribution for subsequent energy analysis. Time- and momentum-resolved two-photon photoemission spectra as a function of layer thickness fully determine the conduction band dynamics at the interface. Earlier clean surface studies showed how excited electron lifetimes are affected by the crystal band structure and vacuum image potential. Recent studies of various insulator/metal interfaces show that the dynamics of excess electrons are largely determined by the electron affinity of the adsorbate. In general, electron dynamics at the interface are influenced by the substrate and adlayer band structures, dielectric screening, and polaron formation in the two-dimensional overlayer lattice.

Journal Article↗
PubMed1997

p53 mutations detected in colorectal carcinoma patients in Hong Kong.

A mutational spectrum for exons 5-8 of the p53 tumor suppressor gene in colorectal carcinomas in Hong Kong Chinese was established. Ninety-nine colorectal carcinomas from Hong Kong patients were analyzed for mutations in p53 gene by PCR-single-strand conformation polymorphism analysis and direct DNA sequencing. Thirty-five of the 99 tumors (35.4%) contained mutations. Point mutations accounted for 80% of all genetic changes and were predominantly base transitions at CpG dinucleotide sites, mutations that were also predominant in Caucasian carcinomas. The major hot spots at codons 175 and 248 of p53 in Caucasians are also hot spots in the Chinese gene. Identical mutations in codons 152 and 306 were detected in two independent tumors in the Chinese, which were reported only rarely in Caucasians. Moreover, a significantly higher frequency (20%) of deletion and insertion mutations was observed in Hong Kong colorectal cancer patients. Distinct genetic and/or environmental factors may contribute to these findings.

Adult↗
PubMed1996

Migration of the AVE Micro coronary stent.

The AVE Micro coronary stent is a balloon-expandable stent with a design that is different from the commonly used slotted tubular or coil stents. The stent delivery system is low in profile and very trackable so that it can negotiate tortuous vessels to reach distal lesions. It also can pass through proximally deployed stents easily. Its moderate radioopacity allows precise stent placement. However, as illustrated in the three case reports presented here, the stent struts did not seem to be firmly embedded into the arterial wall after initial deployment, so that stent migration occurred during subsequent passage of a balloon into the stent for poststenting high pressure balloon dilatation. This new phenomenon of stent migration has not been reported previously with other stents.

Aged↗
PubMed1996

Elective stenting of unprotected left main coronary disease.

For the 12-mo period of 1995, we encountered seven consecutive patients with symptomatic unprotected left main coronary stenosis requiring revascularization. There were five males and two females, age ranging 48-76 years. One patient was referred to coronary bypass surgery. Of the remaining six patients, three refused surgery and the other three, including one with previous bypass surgery and two with previous interventional procedures, preferred percutaneous revascularization. All six had successful elective stenting of their left main coronary stenoses with the new short Palmaz-Schatz stents, P084 and PS104. There were no complications and all remained totally asymptomatic at 3-14 months followup. We conclude that with proper patient selection and the availability of appropriate stents, elective stenting of unprotected left main coronary stenosis is safe with good immediate and medium term results.

Aged↗
PubMed1996

Early clinical experience with the Multi-Link coronary stent.

The Multi-Link coronary stent (Advanced Cardiovascular Systems, Santa Clara, CA) is a balloon expandable stent carved from a stainless steel cylinder and is composed of 12 corrugated rings connected by multiple links. This design gives the stent great flexibility and conformity as well as radial strength. For the 3 month period from November 1995 to January 1996, all patients undergoing stent implantation in our institution were treated with this device, except for vessels smaller than 2.7 mm or larger than 3.7 mm in diameter, left main disease, or those who could not tolerate anticoagulation therapy. Forty patients, with a total of 42 arteries or 44 lesions, were treated with 56 stents, or 1.33 stents per artery. Clinical presentation included stable angina in 13 (32.5%), unstable angina in 24 (60%), acute myocardial infarction in 2 (5%), of whom 1 was in cardiogenic shock, and atypical symptoms with an abnormal thallium stress test in 1 (2.5%). According to the American College of Cardiology/ American Heart Association (ACC/AHA) classification, 8 lesions (18%) were type A, 14 (32%) type B1, 11 (25%) type B2, and 11 (25%) type C. Forty-three lesions (97.7%) were de novo and 1 (2.3%) restenotic. Stent delivery was successful in all patients. Complications included 1 balloon rupture at 7 atm but without sequelae, and 2 patients in whom the coronary guide wire became kinked and locked inside the catheter shaft of the stent delivery system but stent delivery was eventually successful. Mean diameter stenosis was reduced from 76 +/- 13% presenting to 2 +/- 9% poststenting and minimal lumen diameter increased from 0.87 +/- 0.38 to 2.82 +/- 0.34 mm. There were no acute-subacute stent thromboses, bleeding/vascular complications, or major cardiac events such as myocardial infarction, coronary artery bypass surgery, or death during a follow-up period of 2-5 months (mean 3.6 months). In conclusion, our early clinical experience with the Multi-Link stent is very encouraging, with a very high rate of successful delivery and minimal complications.

Adult↗
PubMed1996

Effects of an ambient air pollution intervention and environmental tobacco smoke on children's respiratory health in Hong Kong.

BACKGROUND: Two-thirds of complaints received by the Hong Kong Environmental Protection Department in 1988 were related to poor air quality. In July 1990 legislation was implemented to reduce fuel sulphur levels. The objective of this study was to measure the impact of the intervention on respiratory health in primary school children. METHODS: In all, 3521 children, mean age 9.51 years (SD = 0.78), from two districts with good and poor air quality respectively before intervention were followed yearly from 1989 to 1991. Children and parents reported the children's respiratory symptoms using self-completed questionnaires. Factor analysis was used to derive independent scores from 12 symptoms. Four groups of related symptoms were identified and binary variables (presence of any symptom in each group) were treated as dependent variables in modelling using generalized estimating equations procedures. RESULTS: In 1989 and 1990 an excess of respiratory symptoms was observed in the polluted compared with unpolluted district. The significant effects (odds ratio [OR], 95% confidence interval [CI], P value) associated with living in the polluted district were: cough and sore throat (OR = 1.22, 95% CI: 1.04-1.43, P < 0.01) and wheezing (OR = 1.35, 95% CI: 1.10-1.66, P < 0.01). After the intervention, in the polluted district only, sulphur dioxide levels fell by up to 80% and sulphate concentrations in respirable particulates by 38%. Between 1989 and 1990-1991 there was a greater decline in the polluted compared with the unpolluted district for reported symptoms of cough or sore throat, phlegm, and wheezing. The risks to respiratory health for children exposed to tobacco smoke in the home were higher than those for air pollution in both 1989 and 1990 and remained unchanged in 1991. CONCLUSIONS: Air quality can be improved by fuel controls but an effective intersectoral approach is required if other risks from environmental tobacco smoke are to be avoided.

Air Pollution↗
PubMed1996

Choledocholithiasis in anomalous biliary system.

Although congenital biliary abnormalities are common, preduodenal portal vein is very rare, not to mention preduodenal common bile duct (CBD) which has not been described before in the literature. A case with both anomalies complicated by biliary tract stones is reported. A brief review of embryonic development is also presented to explain the unusual biliary anatomy of this patient.

Adult↗
PubMed1996

Diagnosis, neurobiology, and treatment of pathological gambling.

Pathological gambling is a disabling disorder that affects at least 2 1/2 million Americans and their families. Although pathological gambling has been characterized as an impulse control disorder, it has also been associated with compulsivity. Essential features of pathological gambling include constantly recurring gambling behavior that is maladaptive, in that personal, familial, and/or vocational endeavors are disrupted. Affective disorders and substance abuse often co-occur. Incidence of suicidality is extremely high. Despite the fact that this disorder is a widespread public health problem, few controlled studies of causes or treatment have been conducted. Preliminary neurobiological studies implicate serotonergic dysfunction in pathological gamblers. Treatment with serotonin reuptake inhibitors, such as clomipramine and fluvoxamine, may be effective in treating this disorder. Well-defined and controlled clinical trials in large samples of pathological gamblers are needed.

Adolescent↗
PubMed1995

Clinical application of a new Palmaz-Schatz coronary stent delivery system with a short (8 mm) nonarticulated stent.

The standard Palmaz-Schatz coronary stent delivery system (SDS), with a 15 mm articulated stent and a 5F protective sheath, is relatively rigid and high in profile. Its use is contraindicated in vessels where there is severe tortuosity proximal to or in the lesion itself. Recently a new SDS, with a short (8 mm) nonarticulated stent, has become available. We present three patients with complex coronary anatomy solved with this new SDS. The first patient had a distal stenosis in an extremely tortuous and diffusely diseased right coronary artery (RCA). The second patient had a severe proximal RCA stenosis occurring at a bend of more than 90 degrees. The third patient had a very long stenosis of the left anterior descending coronary artery involving the ostium, requiring multiple tandem stenting. The availability of this short stent will greatly expand the clinical application of intracoronary stenting to patients with complex coronary anatomy.

Aged↗
PubMed1995

Stress and vulnerability in medical students.

One hundred and forty Hong Kong Chinese students were surveyed early in the second year of their medical education (year 2), and compared with 138 students surveyed prior to beginning their first year of medical school and with 74 non-medical university students in their second year. In year 2 students, distress as reflected in their scores on anxiety and depression self-report scales was high, and these students reported greater utilization of health professional services as compared with the other two groups. In year 2 students, concerns related to the medical school environment and curriculum, and whether one has the endurance and ability to be successful were significant correlates with depression and anxiety. Loss of opportunity to maintain social and recreational sources of gratification correlated with anxiety. There was no difference between the sexes with regard to the development of anxiety and depression symptoms. Academically less successful students reported somewhat higher levels of depressive ideation and symptomatology. Trait anxiety correlated with the development of distress, while optimism protected against the development of distress. Active coping styles and positive reinterpretation as a coping strategy correlated negatively with distress, while wishful thinking correlated positively with distress. These findings emphasize the need for greater attention to the psychological well-being of doctors-in-training, in Hong Kong as in the Western world. These findings should be further explored in longitudinal studies, and may be helpful in designing intervention and support programmes for vulnerable students.

Adult↗
PubMed1995

Factors influencing smoking behavior in Hong Kong primary schoolchildren: targets for prevention.

The uptake of smoking by children and factors influencing such behavior, although well documented in the West, have not been studied in the Asia-Pacific region. A cross-sectional survey was carried out on 3,521 children, aged 8-11 years living in two districts of Hong Kong. Knowledge, attitude and behavior related to smoking and sociodemographic data were obtained from questionnaires completed by parents and children. Eleven percent of boys and 5 percent of girls were ever-smokers, 5 percent of all eight-year-olds and 21 percent of 11-year-olds. Believing that parents will not interfere with their smoking (adjusted odds ratio 5.52; 95% confidence interval 2.72, 11.18), living with family members who smoke (1.72; 1.33, 2.23), and having a positive attitude to smoking (4.13; 1.43, 11.98) were factors predictive of ever-smokers. Experimentation with smoking is a major health risk for primary school children in Hong Kong and indicates failure of current smoking prevention programs. Effective culture-specific programs to counteract risk factors and with continuing evaluation are urgently needed; they should be based on information from appropriately-designed epidemiological studies.

Child↗
PubMed1995

Body dysmorphic disorder, pathological gambling, and sexual compulsions.

This article focuses on body dysmorphic disorder (BDD), pathological gambling, and sexual compulsions within the realm of obsessive-compulsive spectrum disorders. These three disorders affect sizable numbers of the population, have an early age at onset and chronic courses, and seem to have a preferential response to serotonin reuptake inhibitors (SRIs). They also have a high comorbidity with obsessive-compulsive disorder, depression, and other impulse control disorders. BDD patients lie more toward the compulsive/risk-aversive end of the dimensional model of obsessive-compulsive spectrum disorder and often have poor insight. Pathological gambling patients lie more toward the impulsivity/novelty-seeking end of the OCD spectrum and often have features of inattention. Sexual obsessions and/or compulsions encompass a heterogeneous group of disorders, as exhibited by differential response to SRIs within this group. These three disorders fall within a new and evolving field that requires further investigation and reconceptualization. This concept may have far-reaching consequences and yield more significant treatment outcomes.

Adolescent↗
PubMed1994

Intracoronary stenting in acute myocardial infarction.

Stent implantation into an infarct-related artery during acute myocardial infarction is generally contraindicated because of the risk of stent thrombosis. We report on 3 patients who had successful stenting for an acute occlusive dissection that developed during direct infarct coronary angioplasty and was refractory to conventional prolonged balloon dilatation, with good long-term clinical and angiographic results. The prerequisites for success include proper premedication, presence of only a minimal amount of thrombus in the infarct-related artery, liberal use of intracoronary thrombolytic therapy, as perfect an angiographic result as possible, as well as careful and aggressive post-stenting anticoagulation.

Angioplasty, Balloon, Coronary↗