Biomedical subjects

K Y Chan

Publications and source records attributed to K Y Chan.

At least 37 records · Page 2Linked to original sources

PubMed2004

Skin-sparing mastectomy.

Skin-sparing mastectomy is still in its infancy in Malaysia. The option of skin-sparing mastectomy is rarely given to patients as many general surgeons perform the conventional mastectomy. This could also be compounded by the lack of awareness amongst the local surgeons on the safety, surgical technique and treatment outcome of this relatively new procedure. This case report demonstrates the feasibility of this procedure performed on a Malaysian patient with a comparable outcome of those reported in the Western countries.

Adult↗

PubMed2004

Tarsal tunnel syndrome caused by ganglion.

We report a case of delayed diagnosis of tarsal tunnel syndrome caused by a ganglion arising from the talo-calcaneal joint. Unusually the symptoms were mainly due to the lateral planter nerve compression with a positive Tinel's sign. A surgical decompression was successful in relieving the dysaesthesia in spite of a 7 years history.

Biopsy, Needle↗

PubMed2003

Juvenile-onset glycogen storage disease type II with novel mutations in acid alpha-glucosidase gene.

The authors describe two novel mutations of the acid alpha-glucosidase gene, P361L and R437C, which define the juvenile-onset glycogen storage disease type II (GSDII) in a 16-year-old Chinese patient. The asymptomatic 13-year-old brother of the proband is also a compound heterozygote of the two mutations. These results confirm that intrafamilial phenotypic variation of juvenile-onset GSDII is ethnically diverse and suggest the contribution of other genes to the phenotypic variability of GSDII.

Adolescent↗

PubMed2003

Benign childhood epilepsy with centrotemporal spikes: a study of 50 Chinese children.

In order to collect local data for children with Benign Childhood Epilepsy with Centrotemporal Spikes (BECTS), we conducted a retrospective study of 50 Chinese children (32 males and 18 females) with BECTS diagnosed in two regional hospitals in Hong Kong from 1995 to 1998. Their peak age of onset was 7 years (range 3-13 years) and a male predominance was observed. Seven patients (14%) had a past history of febrile convulsions and five cases (10%) had a family history of epilepsy. The presentation was protean, but most of them had infrequent, short, nocturnal generalised seizures. The EEG spike foci were most frequently found in mid-temporal regions, followed by centrotemporal regions. Fourteen percent of children did not require anti-epileptic drug treatment. For those who were treated, they were easily controlled on a low dose of carbamazepine (median dosage of 12.75 mg/kg per day) or sodium valproate (median dosage of 20 mg/kg per day). Our study suggested a generally good prognosis for BECTS. No risk factors of frequent seizure recurrence could be identified.

Adolescent↗

PubMed2003

Surgical management of large rotator cuff tears combined with instability in elite rugby football players.

Large rotator cuff tears are extremely uncommon in young people and when they occur they may be associated with shoulder instability. This paper reports on a series of six elite rugby union and rugby league footballers who presented with shoulder instability and large rotator cuff tears. They were treated with a two stage procedure: an open rotator cuff repair followed by an open shoulder stabilisation some 10 weeks later. All had successful outcomes. The paper also highlights the risk of tearing the rotator cuff when a patient continues to play contact sport with an untreated unstable shoulder.

Adult↗

PubMed2003

Outpatient treatment of spontaneous pneumothorax using an improved pocket sized Heimlich valve.

We report two patients, who have used Pneumostat to replace the conventional underwater seal drainage system for recurrent pneumothorax. Both patients had required repeated chest tube insertion for recurrent pneumothorax and needed a longer hospital stay. Both patients were able to be discharged with the Pneumostat device and were reviewed in outpatient clinic. Both patients had optimal clinical improvement and chest X-ray showed no residual pneumothorax.

Ambulatory Care↗

PubMed2002

Infantile isolated sulphite oxidase deficiency in a Chinese family: a rare neurodegenerative disorder.

We report the clinical, biochemical, neuroradiological, and neurophysiological findings of a 4-year-old Chinese girl with infantile isolated sulphite oxidase deficiency. This is the first reported case in our locality. She presented at the age of 5 months with refractory seizures and developmental regression, and progressed rapidly to profound psychomotor retardation, spasticity, dystonia, microcephaly, and blindness. At the age of 3.5 years, she was admitted to the intensive care unit with septic shock. Ophthalmologic examination at this time revealed bilateral dislocation of the lens. Diagnosis of this very rare disorder was made on the basis of increased levels of urinary sulphite, thiosulphate, and sulphocysteine; normal urine xanthine and hypoxanthine; normal plasma uric acid; and low plasma cystine levels. The diagnosis was confirmed by the absence of sulphite oxidase activities in skin fibroblasts. Isolated sulphite oxidase deficiency is a rare inborn error of sulphur metabolism that is difficult to diagnose on clinical features and routine metabolic tests. The presence of ectopia lentis, seizures, and progressive neurological abnormalities should alert clinicians to the diagnosis.

Amino Acid Metabolism, Inborn Errors↗

PubMed2002

A review of burns patients admitted to the Burns Unit of Hospital Universiti Kebangsaan Malaysia.

This is a retrospective review of 110 patients admitted to the Burns Units between October 1999 and November 2001. The aim was to determine the burns pattern of patients admitted to hospital UKM. There was an increasing trend for patients admitted. Female to male ratio was 1:2. Children consisted 34% of the total admission. Children had significant higher number of scald burns as compare to adult (p < 0.01). Domestic burns were consist of 75% overall admission. Mean percentage of TBSA (total body surface area) burns was 19%. Thirty percent of patients sustained more than 20% of TBSA. Sixty percent of patients had scald burns. Ninety percents of patients with second degree burns that were treated with biologic membrane dressing or split skin graft. Mean duration of hospital stay was 10 days. Over 70% of patients were discharged within 15 days. Overall mortality rate was 6.3%. The patients who died had significantly larger area of burns of more than 20% TBSA (p < 0.05) and a higher incidence of inhalation injury (p < 0.02). Hence, this study suggests a need for better preventive measures by the authority to prevent burns related accident and the expansion of the service provided by the Burns Unit.

Adult↗

PubMed2001

Fetal programming of appetite and obesity.

Obesity and related metabolic disorders are prevalent health issues in modern society and are commonly attributed to lifestyle and dietary factors. However, the mechanisms by which environmental factors modulate the physiological systems that control weight regulation and the aetiology of metabolic disorders, which manifest in adult life, may have their roots before birth. The 'fetal origins' or 'fetal programming' paradigm is based on the observation that environmental changes can reset the developmental path during intrauterine development leading to obesity and cardiovascular and metabolic disorders later in life. The pathogenesis is not based on genetic defects but on altered genetic expression as a consequence of an adaptation to environmental changes during fetal development. While many endocrine systems can be affected by fetal programming recent experimental studies suggest that leptin and insulin resistance are critical endocrine defects in the pathogenesis of programming-induced obesity and metabolic disorders. However, it remains to be determined whether postnatal obesity is a consequence of programming of appetite regulation and whether hyperphagia is the main underlying cause of the increased adiposity and the development of metabolic disorders.

Animals↗

PubMed2001

Examining prognostic factors and patterns of failure in nasopharyngeal carcinoma following concomitant radiotherapy and chemotherapy: impact on future clinical trials.

PURPOSE: Concomitant chemotherapy and radiotherapy (CCRT), followed by adjuvant chemotherapy, has improved the outcome of nasopharyngeal carcinoma (NPC). However, the prognosis and patterns of failure after this combined-modality treatment are not yet clear. In this report, the prognostic factors and failure patterns we observed with CCRT may shed new light in the design of future trials. METHODS AND PATIENTS: One hundred forty-nine (149) patients with newly diagnosed and histologically proven NPC were prospectively treated with CCRT followed by adjuvant chemotherapy between April 1990 and December 1997. One hundred and thirty-three (89.3%) patients had MRI of head and neck for primary evaluation before treatment. Radiotherapy was delivered either at 2 Gy per fraction per day up to 70 Gy or 1.2 Gy per fraction, 2 fractions per day, up to 74.4 Gy. Chemotherapy consisted of cisplatin and 5-fluorouracil. According to the AJCC 1997 staging system, 32 patients were in Stage II, 53 in Stage III, and 64 in Stage IV (M0). RESULTS: Univariate analysis revealed that WHO (World Health Organization) Type II histology, T4 classification, and parapharyngeal extension were poor prognostic factors for locoregional control. Multivariate analysis revealed that T4 disease was the most important adverse factor that affects locoregional control, the risk ratio being 5.965 (p = 0.02). Univariate analysis for distant metastasis revealed that T4 and N3 classifications, serum LDH level > 410 U/L (normal range, 180-460), parapharyngeal extension, and infiltration of the clivus were significantly associated with poor prognosis. Multivariate analysis, however, revealed that T4 classification and N3 category were the only two factors that predicted distant metastasis; the risk ratios were 3.994 (p = 0.02) and 3.390 (p = 0.01), respectively. Therefore, based on the risk factor analysis, we were able to identify low-, intermediate-, and high-risk patients. Low-risk patients were those without the risk factors mentioned above. They consisted of Stage II patients with T2aN0, T1N1, and T2aN1 categories and of Stage III patients with T1N2 and T2aN2 categories. Their risk of recurrence is low (4%). Intermediate-risk patients were those with at least one univariate risk factor. They are Stage II patients with T2bN0 and T2bN1 categories and Stage III patients with T2bN2 and T3N0-2 categories. The risk of recurrence is modest (18%). High-risk patients have risk factors by multivariate analysis. They are stage T4 or N3 patients. Their risk of recurrence is high (36%). CONCLUSION: Low-risk patients have an excellent outcome. Future trials should focus on reducing treatment-associated toxicities and complications and reevaluate the benefit of sequential adjuvant chemotherapy. The recurrence in treatment of intermediate-risk patients is modest; CCRT and adjuvant chemotherapy may be the best standard for them. Patients with T4 and N3 disease have poorer prognosis. Hyperfractionated radiotherapy may be considered for the T4 patients. Future study in these high-risk patients should also address the problem of distant spread of the disease.

Adult↗

PubMed2001

Toward a theory of individual differences and leadership: understanding the motivation to lead.

A broad, integrative theoretical framework for understanding the relationship between individual differences and various leader behaviors is presented; it proposes a new individual-differences construct called the motivation to lead (MTL). A large-scale study using 3 samples in different occupational and cultural contexts shows 3 factors underlying MTL, namely, affective-identity, noncalculative, and social-normative MTL. A parsimonious model of antecedents to MTL is developed through hierarchical regression modeling and is cross-validated using confirmatory latent variable modeling. MTL is shown to provide incremental validity over other predictors such as general cognitive ability, values, personality, and attitudes in the prediction of 2 behavioral measures of leadership potential. Findings are discussed with reference to the theoretical framework proposed for understanding individual differences in leader behavior.

Adolescent↗

PubMed2001

Effects of the testing situation on item responding: cause for concern.

The effects of faking on personality test scores have been studied previously by comparing (a) experimental groups instructed to fake or answer honestly, (b) subgroups created from a single sample of applicants or nonapplicants by using impression management scores, and (c) job applicants and nonapplicants. In this investigation, the latter 2 methods were used to study the effects of faking on the functioning of the items and scales of the Sixteen Personality Factor Questionnaire. A variety of item response theory methods were used to detect differential item/test functioning, interpreted as evidence of faking. The presence of differential item/test functioning across testing situations suggests that faking adversely affects the construct validity of personality scales and that it is problematic to study faking by comparing groups defined by impression management scores.

Adult↗

PubMed2001

An unusual encounter of a "cobra" in the heart: rare appearance of an Amplatzer Septal Occluder.

This article presents the unusual appearance of a "cobra" due to "acute bending" of the proximal part and partial opening of the distal part of the left atrial disk of an Amplatzer Septal Occluder during the process of transcatheter closure of a secundum atrial septal defect in a 6-year-old boy. The possible reasons and method to overcome this technical problem, which resulted in successful occlusion of the atrial septal defect, are discussed.

Child↗

PubMed2001

Analysis of P wave and P dispersion in children with secundum atrial septal defect.

BACKGROUND: P maximum and P dispersion are evaluated as predictors of paroxysmal atrial fibrillation in adults. In this study, these variables are being investigated in children with secundum ASD in comparison with that of normal controls and in relation to size of ASD and the presence or absence of atrial dilation. METHODS: Ninety-four children with isolated secundum ASD (33 boys, 60 girls; mean +/- SD age at diagnosis 2.9 +/- 4.1 years) and 65 age-matched controls (mean +/- SD age 4.2 +/- 4.2 years) were evaluated. Resting 12-lead ECG was used to measure P waves from which P maximum and P dispersion (difference between maximum and minimum P-wave duration) were derived. ASD children were arbitrarily subgrouped according to ASD sizes (small: 1-3 mm, moderate: 4-7 mm, large: > or = 8 mm). The presence of right atrial dilation was noted from echocardiography. RESULTS: Children with ASD had significantly longer mean P dispersion compared to controls (P dispersion: 30.2 +/- 11.1 vs 26.4 +/- 6.6 ms, P = 0.008). Mean P maximum and P dispersion were significantly prolonged with increasing ASD size (P < 0.001). Children with right atrial dilation had significantly longer P maximum (102.3 +/- 15.2 vs 82.8 +/- 13.4 ms, P < 0.001) and larger P dispersion (36.1 +/- 12.5 vs 27.6 +/- 9.4 ms, P = 0.003) compared to those without right atrial dilation. CONCLUSION: Prolonged atrial conduction time and inhomogeneity of atrial conduction may possibly be present in children with moderate to large sized ASD and in those with atrial dilation.

Analysis of Variance↗

PubMed2001

Functional segregation of the highly conserved basic motifs within the third endoloop of the human secretin receptor.

In this study, a mutagenesis-based strategy was employed to assess the roles of two highly conserved motifs (KLR and RLAR) within the third endoloop of the human secretin receptor. Block deletion of KLRT and mutation of Lys323 (K(323)I) significantly reduced cAMP accumulation, and these mutations did not affect ligand interaction and receptor number expressed on the cell surface. Thus, the KLRT region at the N terminus of the third endoloop, particularly Lys323, is important for G protein coupling. For the RLAR motif, receptors with substitutions at positions 339 and 342 from Arg to Ala (R(339, 342)A), Glu (R(339, 342)E), or Ile (R(339, 342)I) as well as block deletion of the RLAR motif were all found to be defective in both secretin-binding and cAMP production. Interestingly, a single mutation at the corresponding positions of Arg339 or Arg342 responded as the wild-type human secretin receptor in all functional assays, indicating that the presence of one Arg at either position within the RLAR motif is sufficient for a normal receptor function. Immunofluorescent staining of these mutant receptors showed that these Arg residues are responsible for surface presentation and/or receptor stability.

Amino Acid Motifs↗

PubMed2001

A case series of six children with primary pulmonary hypertension.

INTRODUCTION: Primary pulmonary hypertension is an uncommon but serious disease in children. Management is difficult despite recent advances in pharmacotherapy. CLINICAL PICTURE: We reviewed patients with this condition with respect to their presenting symptoms, investigations, treatment and outcome. TREATMENT: These children were treated with individualised combinations of oxygen, diuretics and calcium antagonists. OUTCOME: In our follow-up of 5 children, 4 had died. CONCLUSION: This condition is irreversible and progressive with a high mortality rate. A better understanding of, and research into, the pathogenesis would hopefully lead to the formulation of improved therapeutic strategies for this condition.

Adolescent↗

PubMed2001

Outcome of meniscus surgery at University Malaya Medical Centre.

Between January 1994 to December 1998, 133 patients had a meniscal surgery at University Malaya Medical Centre. Fifty-four patients were assessed and scored with the Lysholm and Tegner scoring system. Twenty-nine patients had partial meniscectomies and 25 had meniscus repair. The outcome was successful in 80% with meniscal repair and 51.7% with partial meniscectomy. The outcome of meniscal repair in this study is comparable to other reported series. However, the failure rate for partial meniscectomy was high.

Academic Medical Centers↗

PubMed2000

Long-term survival of nasopharyngeal carcinoma following concomitant radiotherapy and chemotherapy.

PURPOSE: The purpose of this study is to demonstrate long-term survival of nasopharyngeal carcinoma treated with concomitant chemotherapy and radiotherapy (CCRT) followed by adjuvant chemotherapy. METHODS AND PATIENTS: One hundred and seven patients with Stage III and IV (American Joint Committee on Cancer, AJCC, 1988) nasopharyngeal carcinoma (NPC) were treated with concomitant chemotherapy and radiotherapy (CCRT) followed by adjuvant chemotherapy between April 1990 and December 1997 in Koo Foundation Sun Yat-Sen Cancer Center, Taipei. The dose of radiation was 70 Gray (Gy) given in 35 fractions, 5 fractions per week. Two courses of chemotherapy, consisting of cisplatin and 5-fluorouracil, were delivered simultaneously with radiotherapy in Weeks 1 and 6 and two additional monthly courses were given after radiotherapy. According to the AJCC 1997 staging system, 32 patients had Stage II disease, 44 had Stage III, and 31 had Stage IV disease. RESULTS: With median follow-up of 44 months, the 5-year overall survival rate in all 107 patients was 84.1%, disease-free survival rate was 74.4%, and locoregional control rate was 89.8%. The 3-year overall survival for Stage II was 100%, for Stage III it was 92.8%, and for Stage IV, 69. 4% (p = 0.0002). The 3-year disease-free survival for Stage II was 96.9%, for Stage III it was 87.7%, and for Stage IV it was 51.9% (p = 0.0001). CONCLUSION: CCRT and adjuvant chemotherapy is effective in Taiwanese patients with advanced NPC. The prognosis of AJCC 1997 Stage II and III disease is excellent, but, for Stage IV (M0), it is relatively poor. Future strategies of therapy should focus on high-risk AJCC 1997 Stage IV (M0) cohort.

Adult↗