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Biomedical subjects

K C Ong

Publications and source records attributed to K C Ong.

At least 19 recordsLinked to original sources
PubMed2006

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in Asians with chronic pulmonary disease: a pilot study.

BACKGROUND: Little is known about the relationship between cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in Asian patients and severe asthma or idiopathic bronchiectasis. We investigated this potential relationship in the Singaporean Chinese. METHODS: Twenty patients with chronic pulmonary disease, 14 with severe asthma and 6 with idiopathic bronchiectasis, were screened for CFTR mutations by direct gene sequencing. The frequencies of identified putative mutations were compared against 40 unaffected controls and 96 unselected population samples. RESULTS: Three missense mutations (I125T, I556V, and Q1352H) and 1 splice site variant (intron 8 12TG5T) were identified in a total of 10 patients, representing a combined mutant/variant allele frequency of 0.25. These alleles were also observed in the controls, but at a significantly lower allele frequency of 0.09 (P<0.01). Furthermore, the I125T mutation was significantly associated with the idiopathic bronchiectasis sub-group (P<0.05). CONCLUSIONS: The significantly higher frequency of CFTR mutations among patients with chronic pulmonary disease compared with unaffected controls suggests that these mutations may increase risk for disease. The association of I125T with idiopathic bronchiectasis alone suggests that different mutations predispose to different disease.

Adult↗
PubMed2006

A comparison of 5% dextrose in 0.9% normal saline versus non-dextrose-containing crystalloids as the initial intravenous replacement fluid in elective surgery.

Intravenous fluid replacement in adult elective surgery is often initiated with dextrose-containing fluids. We sought to determine if this practice resulted in significant hyperglycaemia and if there was a risk of hypoglycaemia if non-dextrose-containing crystalloids were used instead. We conducted a randomized controlled trial in 50 non-diabetic adult patients undergoing elective surgery which did not involve entry into major body cavities, large fluid shifts, or require administration of >500 ml of intravenous fluid in the first two hours of peri-operative care. Patients received 500 ml of either 5% dextrose in 0.9% normal saline, lactated Ringer's solution, or 0.9% normal saline over 45 to 60 minutes. Plasma glucose, electrolytes and osmolarity were measured prior to infusion, and at 15 minutes and one hour after completion of infusion. None of the patients had preoperative hypoglycaemia despite average fasting times of almost 13 hours. Patients receiving lactated Ringer's and normal saline remained normoglycaemic throughout the study period. Patients receiving dextrose saline had significantly elevated plasma glucose 15 minutes after completion of infusion (11.1 (9.9-12.2, 95% CI) mmol/l). Plasma glucose exceeded 10 mmol/l in 72% of patients receiving dextrose saline. There was no significant difference in plasma glucose between the groups at one hour after infusion, but 33% of patients receiving DS had plasma glucose > or = 8 mmol/l. We conclude that initiation of intravenous fluid replacement with dextrose-containing solutions is not required to prevent hypoglycaemia in elective surgery. On the contrary, a relatively small volume of 500 ml causes significant, albeit transient, hyperglycaemia, even in non-diabetic patients.

Adult↗
PubMed2005

Predictors of success in smoking cessation among hospitalized patients.

OBJECTIVE: To determine the predictors of continued smoking abstinence in patients receiving smoking cessation intervention during and following hospital admission. METHODOLOGY: A prospective cohort study was conducted in a university-affiliated hospital. A total of 248 smokers admitted with primary cardiac and respiratory conditions received verbal advice (lasting about 1 h) and standard booklets on smoking cessation from a dedicated nurse counsellor. After discharge, participants received follow-up telephone counselling calls every 2 weeks from the same smoking counsellor. The main outcome measure was continued abstinence at 2 months after hospital discharge, as determined by self-reporting and carbon monoxide breath testing. The following groups of covariates were analysed to determine the possible factors associated with smoking abstinence: demographics, smoking history, readiness to quit, and medical history. RESULTS: At 2 months post-discharge, 108 (43.5%) patients remained abstinent. Low nicotine dependence score (odds ratio, 2.30; 95% CI, 1.25-4.26; P = 0.008), decision to quit by sudden cessation as compared to reduction of smoking (odds ratio, 7.19; 95% CI, 1.56-33.06; P = 0.011), and initial hospitalization for their medical condition (odds ratio, 6.37; 95% CI, 1.33-30.44; P = 0.020) were the main independent predictors for positive outcome. CONCLUSION: Among this cohort of hospitalized patients receiving smoking cessation intervention, low dependence on tobacco, motivation to quit by sudden cessation, and initial hospitalization were the main independent predictors of smoking abstinence after discharge from hospital.

Age of Onset↗
PubMed2001

Effects of a pulmonary rehabilitation programme on physiologic and psychosocial outcomes in patients with chronic respiratory disorders.

INTRODUCTION: The purpose of this prospective study is to determine the effects of a pulmonary rehabilitation programme (PRP) conducted at our centre for patients with chronic lung disease. MATERIALS AND METHODS: Thirty-four patients (27 men and 7 women, mean age 67.7 years) with predominantly moderate-to-severe chronic obstructive pulmonary disease (31 patients), bronchiectasis (2 patients) and interstitial lung disease (1 patient) completed a 6-week outpatient PRP that included education, physical and respiratory care instruction and supervised exercise training. Outcome assessment was performed at baseline, on completion of PRP and 3 months after PRP. Physiologic measures included pulmonary function, incremental exercise and 6-minute walk tests (6MWTs). Disease-specific quality of life was assessed using the Chronic Respiratory Disease Questionnaire (CRDQ). RESULTS: There was no significant change in resting spirometry or lung volumes after PRP. Maximal oxygen uptake and work-rate improved significantly after PRP by 132.4 mL kg-1 min-1 and 10.7 W, respectively. 6MWT distance improved significantly by a mean of 67.3 m (P < 0.0001). Maximum Borg dyspnoea scores decreased significantly by 1.2 +/- 0.5 (P < 0.038). All domains of the CRDQ completed by a sub-group of patients improved significantly and the total scores increased by a mean of 21.7 points at the end of the PRP. The improvements gained in maximal exercise capacity immediately following PRP were maintained in 17 patients who returned for repeat assessment 3 months after PRP. CONCLUSION: Patients who completed a comprehensive PRP at our centre showed significant increase in functional capacity, reduction of exertional dyspnoea and improvement in health status.

Adaptation, Physiological↗
PubMed2001

Neuroleptic malignant syndrome without neuroleptics.

Neuroleptic malignant syndrome is an uncommon condition characterised by hyperthermia, rigidity, altered mentation and autonomic instability. Recognition of this condition is essential because its complications are potentially lethal, leading to death in 20% of patients. Not all cases of this syndrome are associated with the use of neuroleptics and there is an increasing number of reports of this condition occurring after withdrawal of therapy with dopaminergic drugs, typically in patients with Parkinsonism. In this setting, there is tremendous potential for misdiagnosis and delay in institution of treatment because of the traditional and common association of the syndrome with the use of neuroleptics only. We report a case of neuroleptic malignant syndrome in a patient with Parkinsonism subsequent to the withdrawal of levodopa and bromocriptine.

Antiparkinson Agents↗
PubMed2000

Effects of myricetin on glycemia and glycogen metabolism in diabetic rats.

In our previous study, we found that myricetin, a naturally occurring bioflavonoid, was able to stimulate glucose transport in rat adipocytes and enhance insulin-stimulated lipogenesis. We report here that after 2 days of treatment with myricetin (3 mg/12 h), hyperglycemia in diabetic rats was reduced by 50% and the hypertriglyceridemia that is often associated with diabetes was normalised. Treatment with myricetin increased hepatic glycogen and glucose-6-phosphate content. It increased hepatic glycogen synthase I activity without having any effect on total glycogen synthase nor phosphorylase a activity. It lowered phosphorylase a activity in the muscle. Thus, the hypoglycemic effect of myricetin is likely to be due to its effect on glycogen metabolism. There was no indication of serious hepatotoxicity with myricetin treatment and therefore, myricetin could be of therapeutic potential in diabetes.

Animals↗
PubMed2000

A comparative study of pleurodesis using talc slurry and bleomycin in the management of malignant pleural effusions.

OBJECTIVE: Differing success rates of various pleurodesis agents have been reported in the management of malignant pleural effusions. A randomized clinical trial was conducted to compare the efficacy of two commonly used agents, talc and bleomycin, for the pleurodesis of malignant pleural effusions. METHODOLOGY: Inclusion in the study required proof of a malignant pleural effusion by fluid cytology or pleural biopsy. Exclusion criteria included trapped lung, loculated effusions, recurrent effusions and life expectancy < 1 month. Five grams of talc or 1 unit per kilogram bodyweight of bleomycin mixed in 150 mL of normal saline was administered via tube thoracostomy after complete drainage of the pleural effusion in each patient. Treatment success was defined as the absence of recurrent pleural effusion on the chest radiograph 1 month after pleurodesis. RESULTS: Treatment success was achieved in 16 out of 18 patients (89%) in the talc slurry group versus 14 out of 20 patients (70%) in the bleomycin group (P=0.168). Fever and pain were the only side-effects of pleurodesis in both groups. CONCLUSION: These results indicate that talc slurry is as effective as bleomycin in preventing early recurrence of malignant pleural effusions. Pleurodesis with talc instead of bleomycin can result in significant cost savings.

Aged↗
PubMed2000

A case of pulmonary tumour embolism mimicking miliary tuberculosis.

Pulmonary metastases from choriocarcinoma can very rarely give rise to a 'miliary' pattern on the chest X-ray. A 23-year-old woman with a diffuse nodular pattern on chest X-ray died due to acute respiratory failure and cor pulmonale. At autopsy, choriocarcinoma of the uterus was found. In the lungs, multiple macrovascular tumour emboli within branches of pulmonary muscular arteries in the region of segmental/subsegmental bronchi were detected. There was no evidence of pulmonary parenchymal metastases, pneumonia or tuberculosis. The 'miliary' pattern of pulmonary metastases described in cases of choriocarcinoma may be due to large vessel intra-arterial tumour emboli rather than disseminated parenchymal metastases.

Adult↗
PubMed2000

Active management of a patient with endstage pulmonary emphysema using lung volume reduction surgery and intensive rehabilitation.

INTRODUCTION: Lung volume reduction surgery (LVRS) and pulmonary rehabilitation are newer options available in the treatment of advanced emphysema. We describe the progress of our first local patient to have undergone these 2 new treatment modalities. CLINICAL PICTURE: A 65-year-old man with advanced emphysema, limited by crippling dyspnoea despite maximal medical therapy with inhaled bronchodilator therapy, methylxanthines and supplementary oxygen. TREATMENT: Physical reconditioning with a 4-week inpatient pulmonary rehabilitation programme, followed by LVRS and a further 6-week outpatient pulmonary rehabilitation. OUTCOME: Dramatic improvements in spirometric indices, arterial blood gases, exercise capacity and overall functional status. Improvements maintained at one-year follow up period. CONCLUSIONS: LVRS with pulmonary rehabilitation is an exciting new treatment option in a select group of patients with advanced emphysema. Their role in improving overall performance status and quality of life should be considered in patients otherwise considered to have reached the limits of medical therapy.

Aged↗
PubMed2000

The diagnostic yield of pleural fluid cytology in malignant pleural effusions.

BACKGROUND: The development of a pleural effusion in a patient with a known malignancy often raises the possibility that the effusion is due to malignant involvement of the pleura. Accurate diagnosis of the cause of the pleural effusion in such a patient is essential as the treatment and prognosis may vary. Currently, thoracentesis and cytologic analysis of pleural fluid cytology is usually the initial diagnostic step. AIM: To assess the diagnostic yield of pleural fluid cytologic examination in patients with suspected malignant pleural effusions seen at our centre. METHODS: Retrospective review of the results of pleural fluid cytologic examination performed on 103 patients who presented with suspected malignant pleural effusions. RESULTS: The underlying malignancies in these patients were as follows: bronchogenic carcinoma (51.5%), breast carcinoma (29.1%), hepatocellular carcinoma (1.9%), carcinoma of the stomach (1.9%), malignant mesothelioma, nasopharyngeal carcinoma, renal cell carcinoma, carcinoma of the oesophagus, lymphoma, carcinoma of the colon (1% each), unknown (9.7%). Initial pleural fluid cytology was positive for malignancy in 48.5% of patients. The yield of this diagnostic procedure was improved with repeated pleural fluid cytologic specimens and when combined with a percutaneous pleural biopsy. There was no statistically significant difference in the clinical features and pleural fluid characteristics of patients with malignant pleural effusions and those in whom the pleural effusions were paramalignant. CONCLUSION: Pleural fluid cytologic examination is a useful initial step in the diagnostic work-up of patients with suspected malignant pleural effusions. The diagnostic yield of such examination is improved with repeated pleural fluid cytologic specimens and when combined with a percutaneous pleural biopsy. Clinical presentation and pleural fluid characteristics were inadequate in differentiating between malignant and paramalignant effusions.

Biopsy, Needle↗
PubMed2000

Upper airway resistance syndrome--report of three cases.

INTRODUCTION: Patients with the upper airway resistance syndrome are frequently overlooked, and even if clinically suspected, often escape identification by polysomnographic monitoring. CLINICAL PICTURE: Three cases (2 women and a man) with excessive daytime sleepiness and fatigue were confirmed to have the upper airway resistance syndrome after undergoing polysomnography with oesophageal pressure monitoring. TREATMENT: Nasal CPAP during sleep was prescribed for 2 cases but 1 case refused all available treatment options. OUTCOME: After one month of CPAP therapy, the 2 cases reported improved symptoms and Epworth sleepiness scores. Lower daytime blood pressures were also recorded. CONCLUSIONS: Oesophageal pressure monitoring and EEG arousal analysis can greatly enhance the diagnostic accuracy in the upper airway resistance syndrome. Accurate diagnosis and effective treatment of this condition is important because of its sequelae of hypersomnolence and association with other disorders like systemic hypertension.

Electroencephalography↗
PubMed2000

Cardiopulmonary exercise testing in heart transplant candidates.

INTRODUCTION: We evaluated the results of patients with congestive heart failure (CHF) who underwent cardiopulmonary exercise testing (CPET) as part of their assessment for heart transplantation in order to examine the relationship between exercise capacity and resting indices of left ventricular function in these patients. MATERIALS AND METHODS: Twenty-seven ambulatory heart transplant candidates underwent CPET using a cycle ergometer and an incremental work-rate protocol till symptom-limitation. These patients included 24 men and 3 women with a mean age of 42.3 years. The aetiology of CHF was coronary artery disease in 14 patients, dilated cardiomyopathy in 11 patients, and congenital heart disease in 2 patients. Mean resting left ventricular ejection fraction (LVEF) was 19% (range 7% to 36%). RESULTS: Thirteen of the 27 tests performed were maximal studies and all except 2 subjects attained a measurable anaerobic threshold during CPET. Of the 13 maximal tests, the causes of exercise limitation were cardiomyopathy in 3 patients, ischaemic heart disease in 2 patients, significant oxygen desaturation in 2 patients, ventilatory limitation due to obstructive lung disease in 1 patient, ventilatory limitation secondary to a restrictive lung disease in 3 patients, and combined obstructive ventilatory and cardiovascular limitation in 2 patients. There was no significant correlation between resting LVEF and peak VO2 percent predicted (r = 0.14, P = 0.49). CONCLUSIONS: Exercise intolerance in patients with CHF may not be related to limited cardiac reserve and non-cardiac causes of exertional symptoms should also be considered. CPET is useful for the evaluation of functional capacity and mechanisms of exercise intolerance in patients with CHF.

Adult↗
PubMed2000

Cardiopulmonary exercise testing in patients with chronic obstructive pulmonary disease.

INTRODUCTION: Accurate assessment of the exercise capacity of patients with chronic obstructive pulmonary disease (COPD) is important for the dual purpose of exercise prescription and determining response to therapy. Currently, the clinical utility of cardiopulmonary exercise testing (CPET) of patients with COPD as part of their evaluation for pulmonary rehabilitation is not established. The aims of this study were to evaluate the role of CPET in determining maximal exercise capacity and the causes of exercise limitation in patients with COPD. MATERIALS AND METHODS: The results of resting pulmonary function tests and CPET performed on 33 subjects with stable COPD as part of their evaluation for pulmonary rehabilitation were reviewed. Thirty-two of these patients had moderate or severe COPD. RESULTS: Twenty-nine of the 33 patients were able to perform maximal exercise tests during CPET. Of these 29 maximal tests, the causes of exercise limitation were ventilatory limitation in 17 patients, significant oxygen desaturation in 1 patient and both ventilatory limitation and oxygen desaturation in 11 patients. Limb muscle dysfunction is a possible limiting factor in the 4 patients with sub-maximal tests. Physical deconditioning may be a contributory factor of exercise intolerance in 2 patients. Although there was significant correlation (r = 0.597, P = 0.01) between peak VO2 percent predicted and FEV1 percent predicted, there was marked variability of peak VO2 for a given degree of airflow obstruction. CONCLUSIONS: CPET is useful for determining the causes of exercise limitation and for assessing the maximal exercise capacity of patients with COPD.

Aged↗
PubMed1998

Comparison of the severity of sleep-disordered breathing in Asian and Caucasian patients seen at a sleep disorders center.

Race can be considered a risk factor for sleep-disordered breathing (SDB), with higher prevalences and greater severity of the disorder documented among persons of certain racial groups compared with others. Based on clinical observation, it was hypothesized that, other risk factors being equal, Asian patients with SDB have greater severity of their illness compared to Caucasian patients. A cross-sectional study was conducted at a sleep disorders clinic involving 105 Asian patients diagnosed as having SDB after undergoing polysomnography and 99 similarly diagnosed Caucasian patients matched for the following variables: age, gender and body mass index (BMI). The main outcome measure of interest was objective assessment of severity based on polysomnographic data of respiratory disturbance index (RDI) and minimum oxygen saturation (SaO2) during sleep. Symptom scores between patients of the two racial groups were also compared. There were significantly larger proportions of Asians compared to Caucasians with severe obstructive sleep apnea (OSAS) as defined by respiratory disturbance index (RDI) > or = 50 (25.0% vs 11.1%; P = 0.0288) or minimum oxygen saturation (SaO2) < or = 69% (20.6% vs 4.2%; P = 0.0113). The mean minimum SaO2 was significantly lower (P = 0.0001) while the mean (log transformed) esophageal pressure (Pes) value was significantly higher (P = 0.0090) in the Asian group. Logistic regression analysis showed that race was associated with severe SDB (RDI > or = 50) independent of age, sex and BMI. The estimated odds ratio for Asians having severe OSAS compared with Caucasians was 2.51 [95% Confidence Interval (CI) 0.98-6.64]. There was no significant difference in the severity of questionnaire-based symptoms of snoring, apneas during sleep and the median Epworth scores between Asian and Caucasian patients. Based on objective polysomnographic results, Asian patients with OSAS have greater severity of their illness compared to Caucasian patients matched for age, gender and BMI. There was, however, no significant difference in severity of questionnaire-based symptoms between Asian and Caucasian patients with SDB.

Adolescent↗
PubMed1997

Biological effects of myricetin.

1. Myricetin is a natural bioflavonoid whose occurrence in nature is widespread among plants. 2. It has been demonstrated to possess both antioxidative properties and prooxidative properties. 3. It is a potent anticarcinogen and antimutagen, although it has been shown to promote mutagenesis with the use of the Ames Test. 4. Its therapeutic potential and benefits in cardiovascular diseases and diabetes mellitus also are reviewed.

Animals↗