Search PubMed⌕ Search

Biomedical subjects

Y H Chan

Publications and source records attributed to Y H Chan.

At least 91 records · Page 5Linked to original sources
PubMed2000

Obstructive sleep apnea syndrome in obese Singapore children.

We set out to determine the prevalence of obstructive sleep apnea syndrome (OSAS) among obese Singapore school children and identify risk factors for OSAS. This study was designed as a prospective study in three phases. Parents completed a questionnaire with regards to sleep and daytime symptoms in Phase 1. Children suspected to have OSAS based on the questionnaire and all with a percent ideal body weight (IBW) >/=180 were called for clinic visits in Phase 2. All whose percent IBW >/=180 and those in whom the physicians strongly suspected OSAS were subjected to a polysomnogram in phase 3. The children were recruited from the School Health Nutritional Clinic for obese children. The investigations were carried out at Tan Tock Seng Hospital. In all, 3,671 children were screened with the questionnaire. Of these, 146 were selected to undergo polysomnography. Twenty-six had abnormal sleep studies with apnea/hypoxia indices (AHIs) >5/hr. The significant clinical feature which correlated with OSAS was sleep sitting up (P = 0.005). The risk is higher in morbidly obese (IBW >/=180), with a prevalence of 13.3% (8/60), than in less obese children (IBW <180). One in eight (12.5%) of these children was asymptomatic and would have been missed based on the questionnaire. Presence of adenotonsillar hypertrophy led to increased risk of OSAS. The prevalence of OSAS was 0.7% (26/3,671) among the obese schoolchildren in Singapore, which is similar to the prevalence reported by others. Using discriminant analysis, the estimated prevalence increased to 5.7%. In the morbidly obese (IBW >/=180), the prevalence rate is higher at 13.3%.

Adenoids↗
PubMed2000

Vertebral deformity in chinese men: prevalence, risk factors, bone mineral density, and body composition measurements.

The prevalence and risk factors for vertebral deformity were studied in 396 community-dwelling Chinese men aged 70-79 years. Anterior to posterior (H(a)/H(p)), middle to posterior (H(m)/H(p)) and posterior to posterior (H(p)/H(p - 1) or H(p)/H(p + 1)) ratios from T5 to L5 were derived from lateral spine X-ray films, using standardized digitization methods. Using values of 3 standard deviations (SD) or more below the mean and 4 SD or more below the mean as the cutoff, 16% and 7% of these men, respectively, were deemed to have one or more deformed vertebra. Heavy cigarette smoking, heavy alcohol consumption, and working as a heavy manual worker were risk factors for vertebral deformity. Men with severe vertebral deformity (VHR < mean - 4 SD below mean) had much lower body weight, fat mass, and bone mineral density (BMD) than controls. The odds ratios for severe vertebral deformity was 9.9 (95% CI 2.1-45.7) in the lowest quartile of femoral neck BMD.

Absorptiometry, Photon↗
PubMed2000

Comparison of the intraocular pressure-lowering effect of latanoprost and timolol in patients with chronic angle closure glaucoma: a preliminary study.

OBJECTIVE: To compare the intraocular pressure (IOP)-reducing effect and side effects of 0.005% latanoprost once daily to 0.5% timolol twice daily in patients with primary chronic angle closure glaucoma (CACG). DESIGN: Randomized, double-masked two-center clinical trial. PARTICIPANTS: Thirty-two Asian patients with CACG, defined as glaucomatous optic neuropathy with a compatible visual field defect and at least 6 clock hours of synechial angle closure on gonioscopy were recruited. All patients had previous peripheral iridotomy (PI) with IOP >21 mmHg after PI and were thereafter controlled (IOP <22 mmHg) with one or two pressure-reducing drugs. INTERVENTION: After a washout period, the patients were randomized to a 2-week treatment period with either placebo in the morning and 0.005% latanoprost in the evening or 0.5% timolol twice daily. MAIN OUTCOME MEASURES: The short-term IOP reduction of latanoprost and timolol in patients with CACG. IOP was measured at baseline, and after 2, 7, and 14 days of treatment. In addition, the short-term ocular and systemic adverse events of the two drugs were evaluated. RESULTS: Thirty patients completed the study. Two patients in the timolol group were withdrawn because of inadequate IOP control. Compared with baseline, the IOP after 2 weeks of treatment was statistically significantly reduced by 8.8 +/- 1.1 mmHg (mean +/- SEM, P < 0.001) in the latanoprost group, and by 5.7 +/- 0.9 mmHg (P < 0.001) in the timolol group. The difference in IOP reduction between the two treatment groups was 3.1 +/- 1.5 mm Hg in favor of latanoprost (P = 0.04). The main ocular adverse events reported in both treatment groups were conjunctival hyperemia and discomfort. CONCLUSIONS: In this preliminary study, a significantly greater IOP reduction was achieved with 0.005% latanoprost once daily compared with 0.5% timolol twice daily in patients with CACG. The results suggest that latanoprost may be a therapeutic choice for the medical treatment of primary CACG.

Adrenergic beta-Antagonists↗
PubMed2000

Alendronate prevents bone loss in Chinese women with osteoporosis.

The objectives of the Hong Kong study are to investigate the efficacy of 10 mg alendronate in preventing bone loss at the hip and spine in osteoporotic Chinese women. One hundred osteoporotic Chinese women, aged 60-79 years, were randomized to receive 10 mg of alendronate or placebo, with 500 mg elemental calcium. Bone mineral density (BMD) at the spine and hip were measured at baseline, 6 months, and 12 months. Seventy-eight subjects completed the study. The alendronate-treated group gained more bone at both the spine (p < 0.01) and femoral neck (p < 0.001), with a mean difference (+/-SE) of 2.4% (+/-0.86%) at the spine and 3.98% (+/-0.95%) at the femoral neck. Of the 100 patients, 6 subjects in the alendronate group and 5 subjects in the placebo group had mild gastrointestinal symptoms. We conclude that alendronate (10 mg) was effective in preventing bone loss in postmenopausal osteoporotic Chinese women.

Aged↗
PubMed2000

The prevalence and clinical characteristics of pruritus among patients with extensive psoriasis.

BACKGROUND: Many patients with psoriasis are known to suffer from itch. However, the data available regarding itch and its characteristics in psoriasis are sparse. OBJECTIVES: To examine the prevalence of pruritus and various related clinical characteristics in 101 patients with extensive psoriasis. METHODS: A structured questionnaire was used. RESULTS: Generalized pruritus was a feature of psoriasis in 84% of the patients. In 77% of these it appeared on a daily basis. It involved all areas of the body, had prolonged duration and appeared mainly in the evening and at night. The pruritus significantly affected quality of life. Important daily factors that were found to exacerbate the itch were ambient heat (81%), skin dryness (80%), sweating (65%) and stress (55%). Important factors that were found to ameliorate itch were sleep (57%) and cold showers (55%). The pruritus was found to be unresponsive to most available antipruritics, including phototherapy. Itch intensity as reflected by a visual analogue scale did not correlate with Psoriasis Area and Severity Index scores; however, a highly significant correlation was obtained between the affective descriptors and itch intensity in the worst itch states (r = 0.6, P < 0.001). CONCLUSIONS: Pruritus is a common feature of psoriasis and affects quality of life.

Activities of Daily Living↗
PubMed2000

High body mass index, dry scaly leg skin and atopic conditions are highly associated with keratosis pilaris.

BACKGROUND: In a previous study we have found that young patients with insulin-dependent diabetes mellitus had a higher prevalence of keratosis pilaris (KP) than healthy controls, with a high correlation with body mass index (BMI) and ichthyosiform skin changes of the legs. OBJECTIVES: To investigate whether BMI, dry scaly legs and atopic conditions could be associated with KP in a healthy population of adolescents. METHODS: A total of 202 Jewish adolescents chosen at random among students undergoing a routine medical examination at school participated in the study. The patients filled in a questionnaire for data on ethnic origin, the presence or history of allergic rhinitis, asthma or atopic dermatitis, the presence of thyroid disease, diabetes or dry skin. A similar questionnaire was sent to the family physician for verification. A general inspection of the skin was made for the presence of KP; the lower legs were also examined for dry scaly skin and ichthyosiform skin changes. RESULTS: KP was present in 33 examinees (16%). Factors significantly associated with were dry scaly skin (p < 0.001, odds ratio, OR = 31.3, with 95% confidence interval, CI, 6.4-153.7), BMI >25 (p < 0.001, OR = 4.9, with 95% CI 2.2-11.2) and atopy (p = 0.001, OR = 4.5, with 95% CI 1.8-11.1). CONCLUSION: It therefore appears that KP is associated with multiple factors, including high BMI, leg skin dryness and atopic conditions.

Adolescent↗
PubMed2000

The role of alternative therapy in the management of partial thickness burns of the face--experience with the use of moist exposed burn ointment (MEBO) compared with silver sulphadiazine.

INTRODUCTION: Conventional management of partial thickness facial burn wounds includes the use of silver sulphadiazine dressings. Silver sulphadiazine forms an overlying slough that makes wound healing assessment difficult. Moist exposed burn ointment (MEBO) has been proposed as the ideal burn wound dressing both for burns of the face and other sites. Proponents of MEBO claim that it accelerates wound healing and results in scarless wound healing and at the same time reduce bacterial colonisation and the need for analgesics. We present here our experience with MEBO in the management of partial thickness burns of the face. MATERIALS AND METHODS: One hundred and fifteen patients with partial thickness burns were randomly assigned to conventional treatment or MEBO. Out of this, 112 were analysed. Thirty-nine patients sustained facial burns; 17 received MEBO and 22 received silver sulphadiazine. Patients were followed up daily until the burn wounds were reduced by 75% of original body surface area (BSA). RESULTS: In patients with facial burns, MEBO was similar to silver sulphadiazine therapy with respect to rate of wound healing. Minimal slough was present over the wounds in MEBO-treated wounds resulting in clearer assessment of healing progression. CONCLUSIONS: Advantages of MEBO as compared to silver sulphadiazine in the management of partial thickness burns of the face include convenient change of dressing and easier assessment of healing progression. This suggests that MEBO is a useful alternative therapy for partial thickness burns of the face.

Anti-Infective Agents, Local↗
PubMed2000

Sharps and needlestick injuries: the impact of hepatitis B vaccination as an intervention measure.

INTRODUCTION: This paper studies the epidemiology of sharps and needlestick injuries amongst health care workers and the effectiveness of intervention measures implemented at a regional hospital, Singapore. MATERIALS AND METHODS: A retrospective review of sharps and needlestick injuries among healthcare workers of a regional hospital at Singapore between 1992 and 1997. Various interventions namely education, policy changes and a hospital-wide hepatitis B immunisation programme were reviewed for effectiveness of programmes implementation. RESULTS: Of the 347 reported sharps and needlestick injuries, 45.7% occurred in the nursing staff, 25.1% medical staff, 7.5% health attendants, 5.2% hospital cleaners and 3.7% laboratory technicians. A steady rise in reporting was noted amongst the doctors from 1994 and this correlated with the implementation of educational talks given to new medical staff in May 1993. The number of healthcare workers with no previous history of hepatitis B immunisation decreased significantly from 17 in 1996 to 9 in 1997 (P < 0.001, odds ratio = 1.806 with 95% CI 1.443 to 2.261) after the implementation of the hospital-wide hepatitis B immunisation programme. CONCLUSIONS: Levels of awareness may contribute towards changes seen in the number of reporting of injuries. In our experience, we contend that education and appropriate policy changes towards easier reporting help to decrease sharps and needlestick injuries in healthcare workers. The hospital-wide hepatitis B immunisation programme helped to raise the immune status of the staff so as to reduce the costly prophylactic usage of hepatitis B immunoglobulin.

Allied Health Personnel↗
PubMed1999

Spontaneous renal allograft rupture attributed to acute tubular necrosis.

A renal allograft recipient receiving triple immunosuppressive therapy developed spontaneous allograft rupture 5 days after her second cadaveric renal transplantation. Renal biopsy showed interstitial edema with severe acute tubular necrosis (ATN). There was no evidence of acute rejection or renal vein thrombosis. The ruptured renal graft was salvaged by an aggressive fluid resuscitation therapy and surgical hemostasis. The renal function was satisfactory on discharge. We conclude that renal allograft rupture can be the result of interstitial edema solely attributed to ATN in the absence of graft rejection. The ruptured graft kidney is potentially salvageable for those patients whose hemodynamic status can be stabilized by appropriate supportive therapy.

Adult↗
PubMed1998

The health consequences of vertebral deformity in elderly Chinese men and women.

The following health consequences of vertebral deformity in Hong Kong elderly Chinese men and women were studied: the prevalence of back pain, disability due to back pain, and low morale. Lateral X-ray films were taken of the thoracic and lumbar spine of 796 community-dwelling Chinese subjects (396 men, 400 women) (aged 70-79). Subjects with one or more definitely deformed vertebra (reduction in vertebral height 3 SD or more below the mean) were classified as definite cases, those with one or more mildly deformed vertebra (reduction in vertebral height 2-2.99 SD below the mean) as mild cases, and the rest as controls. The prevalence and consequences of back pain were measured by a standardized questionnaire, and morale was measured by the Geriatric Morale Score. The relative risk (RR) and 95% confidence interval (CI) of having back pain and being depressed were calculated by logistic regression. Classifications included 16% of men and 30% of women as definite cases, 37% of men and 35% of women as mild cases, and 47% of men and 35% of women as controls. The relative risk (RR) of back pain was 2.3 (95% CI 1.4-3.9) (P < 0.05) in women with definite deformity and 1.5 (95% CI 0.9-2.5) (P > 0.05) in women with mild deformity, as compared with controls. Sixty-four percent of all men had back pain. This prevalence was much higher than figures obtained in a previous survey on low back pain. The prevalence of back pain did not differ by deformity status, but more men with vertebral deformity were on analgesic. There was no significant association between disability due to back pain and vertebral deformity in women. The RR for having a low morale score (of 5 and below) was 2.3 (95% CI 1.3-4.1) (P < 0. 05) in women with mild deformity; men with vertebral deformity did not have a low morale. It was concluded that vertebral deformity was associated with significant back pain and psychological morbidity in elderly Chinese women. Although men with vertebral deformity did not report more back pain, more were on analgesics than controls.

Aged↗
PubMed1997

Sequence of a cDNA clone encoding a novel somatolactin in goldfish, Carassius auratus.

As a first step towards the development of a sensitive ribonuclease protection assay to study the regulation of somatolactin (SL) mRNA expression in pituitary cells of goldfish, we have isolated a complementary DNA (cDNA) clone encoding precursor sequence of SL from a cDNA library prepared from goldfish pituitary poly(A)+ RNA. The 843-bp goldfish SL (gfSL) cDNA has an open reading frame of 693 nucleotides with two possible start codons of AUG. Amino acid sequence alignment revealed that gfSL has the characteristics of four conserved domains (A, B, C and D) common to all SLs with the domain B being the most conserved region among all the characterized SLs. Similar to other teleost SLs, this gfSL is similarly related but clearly distinct from growth hormone and prolactin of goldfish and other teleosts. However, unlike most other known teleost SLs which have more than 70% amino acid sequence identity to each other, the overall amino acid sequence identity of this novel gfSL with other previously characterized SLs ranges from only 36% to 51%. Moreover, this gfSL contains only six cysteine residues, rather than seven in most other SLs, in conserved positions. Northern blot analysis revealed a single gfSL mRNA transcript of approximately 1 kb in the pituitaries of both sexually regressed and maturing male and female goldfish.

Amino Acid Sequence↗
PubMed1996

Identification of two prolactin cDNA sequences from a goldfish pituitary cDNA library.

We have identified two different cDNA clones encoding for goldfish prolactin (gfPRL) from a pituitary cDNA library. The coding regions of these clones are predicted to encode for an identical amino acid (aa) sequence with four silent mutations. The 3'-untranslated regions (UTRs) of these clones show only 72% nucleotide (nt) sequence identity. The two genes each encoding gfPRL might have derived from recent gene duplication before the divergence of goldfish from other Cypriniforms. Genomic Southern blot analysis of goldfish DNA also demonstrated that there is a small family of two genes for prolactin in the genome of goldfish.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of two distinct growth hormone cDNAs from the goldfish, Carassius auratus.

As a first step toward the development of a ribonuclease protection assay for studying the regulation of growth hormone (GH) gene expression in pituitary cells of the goldfish, Carassius auratus, we report the isolation of two cDNA clones encoding goldfish GH from a cDNA library prepared from pituitary poly(A)+ RNA. The complete nucleotide sequences of these two GH cDNA clones have been determined and both of them were predicted to encode a polypeptide of 210 amino acids (aa) including a putative signal peptide of 22 aa. One of the GH cDNAs encodes a polypeptide (gfGHI) with five cysteine residues (similar to other carp Ms), whereas another encodes a polypeptide (gfGHII) with four cysteine residues (similar to most teleostean GHs). Because these two GH cDNAs have distinct nucleotide sequences at their coding and 3' untranslated regions, they are likely to be encoded by two different genes.

Amino Acid Sequence↗
PubMed1979

Effects of several preoperative medications on fat cell lipolysis, and activity of adipose tissue cyclic AMP phosphodiesterase.

Effects were examined of atropine, diazepam, pethidene, promethazine, scopolamine, omnopon and papaverine on basal and noradrenaline-stimulated lipolysis in rat isolated fat cells and on rat adipose tissue cyclic AMP phosphodiesterase activity. Papaverine at high concentration (1 mM) inhibited both basal and hormone-stimulated lipolysis, whereas diazepam enhanced basal lipolysis. At a 'clinical dose', omnopon increased both basal and noradrenaline-stimulated lipolysis. Adipose tissue cAMP phosphodiesterase activity was strongly inhibited by 1 mM diazepam, papaverine, promethazine and omnopon (280 microgram ml-1). Lack of enhancement of lipolysis by the established cAMP phosphodiesterase antagonist papaverine, is compatible with simultaneous inhibition also of adipose adenyl cyclase. Diazepam-stimulated lipolysis is compatible with its phosphodiesterase inhibitory activity. It is proposed that papaverine-containing omnopon may offer some survival advantages during surgical stress by facilitating a caloric supply.

3',5'-Cyclic-AMP Phosphodiesterases↗