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Biomedical subjects

Y H Chan

Publications and source records attributed to Y H Chan.

At least 19 recordsLinked to original sources
PubMed2004

Benefits of milk powder supplementation on bone accretion in Chinese children.

Low dietary calcium intake has been demonstrated to be a risk factor for hip and vertebral fractures in studies conducted among Hong Kong Chinese. Few studies have demonstrated the effect of milk supplementation in bone accretion in Chinese children. The aim was to examine the effects of milk powder supplementation in enhancing bone accretion in Chinese children. Three hundred and forty-four children, aged 9-10 years old, were randomized to receive milk powder equivalent to 1300 mg and 650 mg calcium, and to a control group, respectively. Bone mineral density (BMD) at the proximal femur, lumbar spine and total body were measured at 6 months, 12 months and 18 months. The treatment effects were modeled using linear mixed effect models and compared using linear contrast F-tests, by intention-to-treat. Subjects randomized to milk powder equivalent to 1300 mg calcium had significantly higher increase in BMD at both the total hip (7.4 +/- 0.4% in treatment group versus 6.3 +/- 0.4% in the control) and the spine (8.4 +/- 0.5% in the treatment group versus 7.0 +/- 0.5% in the control group). Subjects randomized to milk powder equivalent to 650 mg calcium had smaller increases in BMD at the total hip and spine, although the increase in BMD at the total body was significantly higher (3.1 +/- 0.3% in treatment group versus 2.4 +/- 0.2% in controls). It is concluded that supplementing the diet of Chinese children with milk powder was effective in enhancing bone accretion.

Animals↗
PubMed2004

Acoustic rhinometry in nasal allergen challenge study: which dimensional measures are meaningful?

BACKGROUND: Acoustic rhinometry (AR) is commonly used as a quantitative assessment of nasal response to nasal allergen challenge (NAC). However, sources of error and physical limitations of various AR area-distance measurements have not been adequately evaluated. OBJECTIVE: To investigate the clinical value of AR measurements, and the relationship between subjective sensation and objective AR measurements in the NAC study. METHODS: Nasal challenge using increasing concentrations of crude Blomia tropicalis (Bt) extracts (0.6, 6, and 60 microg/mL) was performed in 15 adult patients (eight males and seven females) with ongoing persistent allergic rhinitis. Subjective symptom scores of nasal obstruction were recorded together with the objective AR measurements of the minimum cross-sectional area (MCA), distance to MCA and cross-sectional area (CSA) at 3.3, 4.0 and 6.4 cm from the nostril, during the 7 h after the last challenge. RESULTS: The dose-response increase in nasal obstruction score was significantly (P<0.001 for all) associated with decreases in mean MCA (r=0.75), mean CSA3.3 (r=0.54), mean CSA4.0 (r=0.53) and mean CSA6.4 (r=0.20). The mean MCA (+/-SD) for each subjective symptom score 0, 1, 2 and 3 was found to be 0.73 (+/-0.22) cm2, 0.63 (+/-0.29) cm2, 0.33 (+/-0.17) cm2 and 0.21 (+/-0.14) cm2, respectively. When the MCA (left and right separately) reached an area <0.2 cm2, measurements of CSA3.3 and CSA4.0 were significantly reduced by 60-70%. CONCLUSION: This study demonstrates that AR is a useful and objective investigational tool, which correlates well with the sensation of nasal obstruction. MCA, CSA3.3 and CSA4.0 are more reliable measurements than CSA6.4 due to physical limitations. It is important to note that when the MCA is smaller than 0.2 cm2, a common condition in the early-phase reaction, area-distance measurements beyond this point can be misinterpreted and should be considered with caution.

Adult↗
PubMed2004

Quantitative computer-assisted digital-imaging upper airway analysis for obstructive sleep apnoea.

This was a prospective study of a new objective method which quantitatively analyses the upper airways in patients with obstructive sleep apnoea (OSA). Video-nasopharyngoscopic examinations of the upper airways of 45 patients were carried out with an endoscopic calibrator. Images of the upper airway during quiet respiration and Mueller's manoeuvre in erect and supine positions were digitized by computer to generate the actual dimensions of obstructive sites. Measurements by the new method were validated by comparing 90 pairs of videoendoscopic images with upper airway magnetic resonance imaging (MRI) measurements at two identical levels. Quantitative precision is 100% for the retropalatal level and 95.6% for the retrolingual level with a tolerance of 0.5 cm(2) between the two methods. The absolute mean of the difference between the two methods of measurement is 0.08 cm(2) at the retropalatal level and 0.18 cm(2) at the retrolingual level. The agreement between the digital-imaging videoendoscopic and MRI measurements was 93.3% for the retropalatal level and 95.6% for the retrolingual level. Quantitative computer-assisted digital imaging is a reliable, cost-effective clinical method of upper airway evaluation in OSA patients. This method allows us to examine the dynamic and static morphology objectively, measure surgical outcomes of upper airway, opening up new avenues for OSA management.

Body Mass Index↗
PubMed2004

A clinical survey on compliance in the treatment of rhinitis using nasal steroids.

BACKGROUND: In the treatment of persistent rhinitis, the observed efficacy with intranasal steroids in clinical practice often falls short of that reported in clinical trials. We postulate that this could be due to patient non-compliance and thus designed this study to evaluate the impact of patient compliance on the efficacy of treatment in patients with persistent rhinitis. METHODS: Sixty-three consecutive adult patients with allergic and non-allergic rhinitis, treated with intranasal triamcinolone acetonate, were included in the study. Compliance was determined both by direct questioning and by measuring the weight of medication consumed (WMC) after 30 days of therapy. Nasal symptom scores were used to determine treatment efficacy. RESULTS: Forty-nine patients (77.8%) reported a forgetfulness of using medication for a few times (1-5 times) during the treatment period. Less than 50% compliance was reported by one patient (1.6%) but detected in seven patients (11%) by WMC. There was a significant (P < 0.001) improvement in mean total symptom score before (7.45 +/- 1.99) and after (3.59 +/- 2.72) treatment in patients with WMC of at least 50%, but not when WMC was <50% (8.43 +/- 1.72 vs 6.29 +/- 2.43; P = 0.114). With >50% WMC, the positive predictive values for relief of each symptom were rhinorrhoea: 78%, nasal itch: 70%, nasal obstruction: 67% and sneezing: 65%. CONCLUSION: Patients compliance has a significant impact on treatment efficacy with intranasal steroids. There is a discrepancy between reported and actual compliance. It is thus important to establish the actual compliance when evaluating patients who fail to respond to therapy.

Administration, Intranasal↗
PubMed2004

Six month radiological and physiological outcomes in severe acute respiratory syndrome (SARS) survivors.

BACKGROUND: The long term physiological and radiological outcomes of SARS survivors and their possible determinants are uncertain. METHODS: SARS survivors in a follow up clinic in a regional hospital underwent high resolution computed tomography (HRCT) of the thorax and lung function tests 6 months after admission to hospital. The associations between the clinical and demographic data of the patients and the physiological and radiological outcomes were examined. RESULTS: Fifty seven patients took part in the study. Lung function abnormalities were detected in 43 patients (75.4%), with restrictive defects (n = 16) being most common (28.1%). Radiological abnormalities of any degree were detected in 43 patients (75.4%). Only the use of pulse corticosteroids was associated with the presence of CT abnormalities (p = 0.043, OR 6.65, 95% CI 1.06 to 41.73). CONCLUSIONS: Physiological and radiological abnormalities are still present in a considerable proportion of SARS survivors at 6 months.

Adult↗
PubMed2004

Interleukin-2 levels in chronic schizophrenia patients.

INTRODUCTION: Most research in interleukin activity in schizophrenia has been in Caucasian populations. We examined interleukin-2 (IL-2) levels and their relation to the duration of the illness, psychopathology and treatment effects, in chronic schizophrenia patients of Asian origin. MATERIALS AND METHODS: Thirty chronic schizophrenia patients were recruited for the study and their demographic data and medication dosage were noted. Symptom severity was scored on the Positive And Negative Syndrome scale for Schizophrenia (PANSS) and blood sampling done. Ten healthy Chinese males were recruited as controls. Phytohaemagglutinin-stimulated production of serum levels of IL-2 were measured by enzyme-linked immunosorbent assay. RESULTS: IL-2 levels (1327 +/- 596.2) of all 30 patients were significantly lower than that of the Chinese controls (2420 +/- 342.5). This effect was noted throughout the entire duration of the illness. Ethnic and age differences in IL-2 levels were not found. There was, however, a negative correlation with the duration of the illness and a positive correlation with the dosage of medication. CONCLUSIONS: The results of this study of a population of mostly Chinese patients with schizophrenia replicate an important finding. Data such as this has not been reported previously on Asians of this racial group.

Adult↗
PubMed2004

Corticosteroid therapy in a Chinese patient with nephropathy associated with human immunodeficiency virus infection.

A 52-year-old man with 6 years' history of human immunodeficiency virus infection who was receiving highly active antiretroviral therapy presented with acute renal failure and nephrotic syndrome. Renal biopsy revealed features consistent with nephropathy associated with human immunodeficiency virus infection. Treatment consisted of intravenous methylprednisolone followed by oral prednisolone. The patient's renal function improved, although proteinuria persisted. Human immunodeficiency virus-associated nephropathy is very rare in Asian populations and is more common among blacks. To the best of our knowledge, this is the first documented case of nephropathy associated with human immunodeficiency virus infection occurring in Hong Kong.

AIDS-Associated Nephropathy↗
PubMed2004

Public attitudes to emergency medical services in Singapore: EMS day 2002.

INTRODUCTION: In the year 2002, the Society for Emergency Medicine in Singapore Chapter of Paramedics organised the first emergency medical services (EMS) day, to educate the public about basic emergency response skills and to increase public awareness of the local EMS System. METHODS: This was an observational, cross-sectional study. A survey was conducted to find out about the knowledge and attitudes of the public and paramedic volunteer instructors towards the local EMS System. RESULTS: Two hundred and six (81.4 percent) out of 253 members of the public and 70 paramedics (100 percent) responded. For the public, the majority were females (86 percent), mean age (standard deviation [sd]) was 15.9 (7.9) years, range 11.0 to 67.0 years. For the paramedics, mean (sd) age was 26.6 (3.8) years. 61.9 percent were females. The public showed good knowledge of the emergency ambulance number and the indications for calling an ambulance. Public expectations of ambulance response times were significantly shorter than paramedics. They were also less comfortable with ambulance crews performing advanced life support interventions compared with the paramedics. CONCLUSION: Continuing efforts should be made to increase public awareness of the EMS system as well as to manage public expectations regarding response times and the roles of paramedics. EMS day represents one such opportunity.

Adolescent↗
PubMed2004

Relationships between depression/somatization and self-reports of pain and disability.

AIMS: To examine the relationship between depression and somatization and pain during muscle and joint palpation as well as limitations related to mandibular functioning (LRMF) in patients with temporomandibular disorders. METHODS: The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) data for Axes I and II for 196 consecutive patients (56 men and 140 women) with a history of facial pain were obtained. The mean age of the predominantly Chinese patient population (83.2%) was 33.4 years (range 18 to 55 years). A computerized diagnostic system was used to collect the RDC/TMD history data. The Symptom Check List (SCL-90) depression and somatization scales were generated on-line and archived. The mean muscle pain (MP), joint pain (JP), and LRMF scores were computed with depression and somatization as main effects. Data were subjected to analysis of variance (Scheffé test) and Pearson's correlation at a significance level of .05. RESULTS: Depression scores ranged from 4.03 to 8.16 (MP), from 0.67 to 1.03 (JP), and from 0.30 to 0.38 (LRMF); somatization scores ranged from 2.64 to 7.75 (MP), from 0.58 to 1.00 (JP), and from 0.30 to 0.41 (LRMF). Interaction effects between depression and somatization were not significant. Patients with severe depression had significantly higher MP scores than normal patients or patients with moderate depression. Patients with moderate and severe somatization had significantly higher MP scores than normal patients. LRMF scores of patients with severe somatization were significantly greater than those who were normal or suffered from moderate somatization. No significant difference in JP scores was observed for depression and somatization scales. Correlations between depression/somatization and MP, JP, and LRMF scores were significant and positive but weak; coefficients ranged from 0.15 to 0.41. CONCLUSION: The results suggest that depression and somatization are related to the self-report of MP. In addition, severe somatization may be associated with an increase in jaw disability.

Adolescent↗
PubMed2003

Thermosensory abnormalities and blood flow dysfunction in psoriatic skin.

BACKGROUND: Accumulating data have shown evidence of involvement of cutaneous nerve fibres and neuropeptides in psoriasis. Although ample evidence of structural and biochemical data exist no studies have been done on assessing the function of small nerve fibres in this disease. OBJECTIVES: To investigate the function of small nerve fibres in patients with psoriasis between psoriatic plaques and non-involved skin and in comparison with healthy controls. METHODS: We performed computerized psychophysical thermal sensory testing of warmth, cold and heat pain thresholds and skin blood flow using laser Doppler imaging in psoriatic lesions vs. non-involved skin and healthy skin. We evaluated these parameters before and immediately after barrier perturbation, and 1 week after as a measure of barrier repair. RESULTS: There is a significantly elevated warm and decreased cold sensation threshold in psoriatic skin compared with non-involved skin and skin of healthy controls in the same sites. These differences were particularly abnormal 1 week poststripping. The warm sensation threshold was significantly elevated in non-involved skin in psoriatics vs. skin of healthy controls after tape stripping. These findings suggest there is an abnormal function of cutaneous nerve fibres in response to trauma to the stratum corneum, which is not limited to the visible plaque but could be generalized and aggravated by stressful events. Skin blood flow was significantly elevated in psoriatic plaques and inversely correlated to warm sensation thresholds while in healthy controls a direct correlation was noted. CONCLUSIONS: Our data demonstrate an abnormal thermosensory response in psoriasis.

Adult↗
PubMed2003

Short term outcome and risk factors for adverse clinical outcomes in adults with severe acute respiratory syndrome (SARS).

BACKGROUND: Severe acute respiratory syndrome (SARS) was diagnosed in Hong Kong in over 1700 patients between March and early June 2003. METHODS: 115 patients diagnosed with SARS were admitted to Queen Elizabeth Hospital, a large regional hospital in Hong Kong, from March 2003, of whom 100 were either discharged or were dead at 31 May. The patients were prospectively studied after admission to assess their short term outcomes and the risk factors associated with adverse outcomes, defined as death or the need for mechanical ventilation RESULTS: At the time of writing 18 patients had died, with a crude mortality rate of 15.7% and a 21 day mortality of 10% (standard error 3%). Thirty nine patients (34%) were admitted to the intensive care unit, 30 of whom (26%) required mechanical ventilation. Multivariate analysis showed that age above 60 (hazards ratio (HR) 3.5, 95% CI 1.2 to 10.2; p=0.02), presence of diabetes mellitus or heart disease (HR 9.1, 95% CI 2.8 to 29.1; p<0.001), and the presence of other comorbid conditions (HR 5.2, 95% CI 1.4 to 19.7; p=0.01) were independently associated with mortality. However, only the presence of diabetes mellitus and/or cardiac disease (HR 7.3, 95% CI 3.1 to 17.4; p<0.001) was associated with adverse outcomes as a whole. CONCLUSION: SARS is a new disease entity that carries significant morbidity and mortality. Specific clinical and laboratory parameters predicting unfavourable outcomes have been identified.

Adult↗
PubMed2003

Five-year review of adolescent mental health usage in Singapore.

INTRODUCTION: To provide a review of adolescent mental health service utilisation in a child and adolescent mental health outpatient clinic in Singapore. MATERIALS AND METHODS: Data from all new adolescent cases seen over a 5-year period in the Child Guidance Clinic were analysed. A review of services provided is also included. RESULTS: Adolescent mental health usage has been on an increase with a rise in the number of cases diagnosed with depression. There has also been an increase in the number of forensic cases seen in the department. CONCLUSIONS: There is a growing demand for adolescent mental health services. As the demands and stresses on today's youth increase, there is likely to be a continued increase in the demand for such services. The challenge in the future is to provide adolescent mental health services in cost-effective packages that will meet the needs as well as stay financially viable.

Adolescent↗