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Biomedical subjects

M Choo

Publications and source records attributed to M Choo.

At least 19 recordsLinked to original sources
PubMed1998

Cardiovascular risk factors in non-insulin-dependent diabetics compared to non-diabetic controls: a population-based survey among Asians in Singapore.

Cardiovascular risk factors were compared between 126 people with non-insulin-dependent diabetes mellitus (NIDDM) and 530 non-diabetics (controls), in a random sample of people (Chinese, Malays, and Asian Indians) aged 40-69 years from the general population of Singapore. Data were adjusted for age and ethnicity. For both genders, people with NIDDM had higher mean body mass indices, waist-hip ratios and abdominal diameters. They also had a higher prevalence of hypertension, higher mean levels of fasting serum triglyceride, slightly lower mean levels of serum high-density-lipoprotein cholesterol, and higher mean levels of plasma plasminogen activator inhibitor-1 and tissue plasminogen activator (antigen). These factors are components of syndrome X (metabolic syndrome) and increase the risk of atherosclerosis and thrombosis. In contrast, there were no important differences for cigarette smoking, serum total and low-density-lipoprotein cholesterol, serum apolipoproteins A1 and B, plasma factor VIIc and plasma prothrombin fragment 1 + 2. Females with NIDDM, but not males, had a higher mean serum fibrinogen level than non-diabetics, which could explain why NIDDM has a greater cardiovascular effect in females than males. Serum lipoprotein(a) concentrations were lower in people with NIDDM. Mean levels of serum ferritin, a pro-oxidant, were higher in people with NIDDM than controls, but there were no important differences for plasma vitamins A, C and E, and serum selenium, which are anti-oxidants.

Arteriosclerosis↗
PubMed1998

Cardiovascular risk factors in relation to cigarette smoking: a population-based survey among Asians in Singapore.

To investigate how cigarette smoking increases the risk of cardiovascular disease, risk factors were compared between 166 cigarette smokers and 312 non-smokers, in a random sample of males (Chinese, Malays and Asian Indians) aged 30-69 years from the general population of Singapore. There was adjusted for age and ethnic group. The prevalence of hypertension was lower in cigarette smokers (15.2%) than non-smokers (21.9%), with the difference reduced by adjustment for body mass index (BMI). Smokers had: lower mean serum HDL-cholesterol (0.76 versus 0.81 mmol/l) and higher mean serum fasting triglyceride (1.92 versus 1.71 mmol/l), which will increase atherosclerosis; higher mean plasma fibrinogen (2.75 versus 2.67 g/l) and plasminogen activator inhibitor 1 [PAI-1] (24.9 versus 22.2 ng/ml), which will increase thrombosis; and lower mean plasma vitamin C (4.4 versus 6.4 mg/l) and serum selenium (118 versus 123 microg/l), which may increase atherosclerosis. Adjustment for BMI slightly increased the differences for HDL-cholesterol, fasting triglyceride, fibrinogen and PAI-1, indicating that less generalised obesity among smokers reduces their increased cardiovascular disease risk. Smoking was not found to be related to: diabetes mellitus; serum total cholesterol, LDL-cholesterol, apolipoproteins A1 and B and lipoprotein(a); plasma factor VIIc and prothrombin fragment 1 + 2; and plasma vitamins A and E and serum ferritin. There was no evidence of increased insulin resistance in smokers, as measured by mean fasting serum insulin.

Adult↗
PubMed1998

Candidal epididymo-orchitis: case report and review.

We describe a case of epididymo-orchitis with candiduria and histologically proven epididymal abscesses due to Candida albicans and review six previously reported cases. Candidal epididymo-orchitis occurs in patients with recognized risk factors for candidal infection, often after instrumentation of the urinary tract. Cases caused by both C. albicans and Candida glabatra have been described. Drainage or orchidectomy may be required for definitive diagnosis and treatment. Treatment with oral antifungals alone has been effective in two cases.

Aged↗
PubMed1997

Central obesity, insulin resistance, syndrome X, lipoprotein(a), and cardiovascular risk in Indians, Malays, and Chinese in Singapore.

STUDY OBJECTIVE: To examine the hypothesis that the higher rates of coronary heart disease (CHD) in Indians (South Asians) compared with Malays and Chinese is at least partly explained by central obesity, insulin resistance, and syndrome X (including possible components). DESIGN: Cross sectional study of the general population. SETTING: Singapore. PARTICIPANTS: Random sample of 961 men and women (Indians, Malays, and Chinese) aged 30 to 69 years. MAIN RESULTS: Fasting serum insulin concentration was correlated directly and strongly with body mass index (BMI), waist-hip ratio (WHR), and abdominal diameter. The fasting insulin concentration was correlated inversely with HDL cholesterol and directly with the fasting triglyceride concentration, blood pressures, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA), but it was not correlated with LDL cholesterol, apolipoproteins B and A1, lipoprotein(a), (Lp(a)), fibrinogen, factor VIIc, or prothrombin fragment (F)1 + 2. This indicates that the former but not the latter are part of syndrome X. While Malays had the highest BMI, Indians had a higher WHR (men 0.93 and women 0.84) than Malays (men 0.91 and women 0.82) and Chinese (men 0.91 and women 0.82). In addition, Indians had higher fasting insulin values and more glucose intolerance than Malays and Chinese. Indians had lower HDL cholesterol, and higher PAI-1, tPA, and Lp(a), but not higher LDL cholesterol, fasting triglyceride, blood pressures, fibrinogen, factor VIIc, or prothrombin F1 + 2. CONCLUSIONS: Indians are more prone than Malays or Chinese to central obesity with insulin resistance and glucose intolerance and there are no apparent environmental reasons for this in Singapore. As a consequence, Indians develop some but not all of the features of syndrome X. They also have higher Lp(a) values. All this puts Indians at increased risk of atherosclerosis and thrombosis and must be at least part of the explanation for their higher rates of CHD.

Adult↗
PubMed1995

A telemedicine system for high-quality transmission of paper electrocardiographic reports.

To overcome problems associated with the faxing of ECGs, we developed a telemedicine system providing fast transmission of ECGs between physicians and cardiologists at different locations. It digitized ECGs at a resolution of 300 dots/inch (118 dots/cm), processed them, and transmitted them over a standard telephone line in under one minute. The system also paged the cardiologist in order to direct him or her to the location where the ECG would be waiting for interpretation. The system enabled physicians at remote locations to consult using voice, images and simultaneous cursor pointers. A transmitting site was set up at the Medical Centre of the Ministry of Defence and a receiving site at the National University Hospital, about 5 km away. During a six-month trial, 200 ECG reports were transmitted from one site to the other. They were rated excellent in quality by the cardiologists, being virtually indistinguishable from the originals. Our telemedicine system transmits high-quality ECGs rapidly and at low cost.

Algorithms↗
PubMed1995

Diagnosis of deep vein thrombosis using duplex ultrasonography.

Duplex ultrasonography is a safe, accurate, efficient, inexpensive, noninvasive diagnostic test for deep vein thrombosis (DVT). The sensitivity and specificity of this technique is comparable to venography in symptomatic patients in many studies. The diagnostic accuracy of this test can be further enhanced by serial studies. We report our experience with the use of this technique for study of 180 patients with clinically suspected DVT. Only 55 (30.6%) patients were confirmed to have DVT on duplex ultrasonography which illustrates the inaccuracy of bedside diagnosis of this potentially life-threatening condition. Almost all our DVT patients have proximal vein involvement, indicating that venous thrombosis usually do not cause signs or symptoms until they become large, occlusive and extend into the proximal veins. It is also observed in our study cohort that half of the patients with proximal vein thrombosis has incomplete recanalisation on follow-up study. None of them with normal study developed significant sequelae of untreated DVT, suggesting that it is safe to withhold treatment based on result of this non-invasive test. Duplex ultrasonography is the diagnostic modality of choice for suspected DVT in symptomatic patients and is an excellent substitute for conventional contrast venography.

Adult↗
PubMed1995

Stenting of stenosis of the abdominal aorta.

Isolated abdominal aortic stenosis resulting in bilateral lower limb claudication is uncommon in Asians. We report a 75-year-old Oriental man with isolated abdominal aortic stenosis who underwent intraluminal stenting, resulting in the abolishment of a 76 mmHg gradient. As the stenotic segment was local, only the mid-segment of the Palmaz stent was apposed to the aortic wall. Follow-up ultrasound scans showed that the partially apposed stent was potent, with no thrombosis in the free space between the stent and the wall. Hence, although aortic stenting in this patient resulted in partial apposition of the stent to the aortic wall, there was no thrombosis or migration of the stent. The patient remained symptom-free one year post-stenting. Stenting in this patient with failed balloon angioplasty was a safe and efficacious method of treating significant isolated abdominal aortic stenosis.

Aged↗
PubMed1994

Influence of circulating D-dimer levels on assays of fibrinogen.

The influence of circulating D-dimer levels on two different assays for fibrinogen was studied in 31 normal female subjects, 18 late pregnant subjects, 8 male subjects with acute myocardial infarction (AMI) and 9 subjects with unstable angina (UA). Both functional and chemical methods for fibrinogen showed significant correlation (r = 0.8171; P < 0.001). However, values for fibrinogen were significantly lower using the functional method in normal females, AMI and UA patients with mean (SD) ratios of 0.88 (0.11), 0.78 (0.17) and 0.84 (0.09) respectively as compared to the chemical assay method. In late pregnancy this was not observed with a mean ratio of 1.09 (0.22) obtained between the two methods. The D-dimer level in normal subjects was mean 194 (95.3) ng/ml whilst in late pregnancy, in AMI and UA, the levels were significantly elevated at 1093 (1034), 382 (216) and 1056 (708) ng/ml respectively. Significant correlation between fibrinogen and D-dimer levels was observed only in AMI and UA patients but not in late pregnancy. In 3 patients with AMI undergoing thrombolysis, no functional fibrinogen was detectable for the first 12 h following intravenous streptokinase (SK) despite the presence of chemically detectable fibrinogen with values of 13% to 30% of pre-treatment levels and evidenced by lytic states evaluated by thromboelastography (TEG). Grossly elevated D-dimer levels of between 25 x 10(3) and over 100 x 10(3) ng/ml were present during this time. Functional fibrinogen was detectable by 24 h following SK therapy but its level in relation to fibrinogen detected chemically remained depressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Total occlusion of left main coronary artery in Orientals: profile of 4 cases.

The authors report 4 Oriental cases of total occlusion of the left main coronary artery (LMCA) with differing presentations. The first patient had a twelve-year history of stable angina pectoris. The second patient had angina for a year, which became unstable two months prior to diagnosis. The third patient had myocardial infarction seven years ago and presented with a one-month history of rest angina. The fourth patient had stable effort angina for six years but presented with accelerated angina three months prior to diagnosis. The incidence of total occlusion of the LMCA is rare and survival depends on the existence of collateral circulation. In LMCA disease, there is usually disease in other parts of the coronary arterial tree, and hence, the need for urgent coronary bypass surgery.

Angina Pectoris↗
PubMed1993

Review of patients with infective endocarditis of native valves over a five-year period.

The clinical characteristics, echocardiographic features, bacteriologic data, morbidity and mortality of patients who were admitted to our hospital with infective endocarditis of their native valves over a five-year period were reviewed. There were 32 patients with a mean age of 38.2 +/- 16.2 years (range: 17 to 71 years) in our study population; 24 patients had underlying valvular abnormalities, six patients had congenital heart disease and two patients had no structural cardiac abnormality. Echocardiography was performed for all patients. Vegetations were absent in three (9.4%) patients, single in 19 (59.4%) patients and multiple in ten (31.3%) patients. Of the 24 (75%) patients who had left-sided endocarditis, mitral valve disease was the commonest valvular abnormality (16 patients). Ventricular septal defect was the commonest underlying abnormality in patients with right-sided endocarditis. Blood cultures were positive in 26 (81.3%) patients; the commonest organism was streptococcal (16 or 50% patients). Complications were present in 13 (40.6%) patients, of which eight patients had evidence of embolism, four patients had cardiac failure and one patient had a paravalvular abscess. Four (12.5%) patients died, two as a result of refractory heart failure and two as a consequence of septic embolism. Advances in medicine have resulted in a better outcome for patients with infective endocarditis, however, it remains an important disease with significant morbidity and mortality.

Adolescent↗
PubMed1992

Distribution and antioxidant activity of a palm oil carotene fraction in rats.

The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to correlate the accumulation of carotenoids with protection against oxidative stress. We found that: (i) After 2 weeks beta-carotene in the liver increased from 7.3 to 30 ng/g wet tissue; alpha-carotene and lycopene after 10 weeks of feeding were 74 and 49 ng/g wet tissue respectively; (ii) Beta-carotene content in heart and hind limb skeletal muscles increased after 10 weeks to 17 and 6 ng/g wet tissue respectively; (iii) No carotenoids were detected in the brain, adipose and skin during the period of feeding; (iv) After in vitro induction of lipid peroxidation in liver homogenates by an azo-initiator of peroxyl radicals an inverse correlation between tissue carotenoid level and accumulation of lipid peroxidation products was observed; alpha-carotene > lycopene > beta-carotene.

Adipose Tissue↗
PubMed1990

Comparison of serum phenobarbital levels after single versus multiple attempts at intraosseous infusion.

Serum drug levels from a single intraosseous attempt in nontraumatized bone have proven comparable to levels from IV drug infusions. However, in the clinical situation, inexperienced personnel may make multiple intraosseous attempts, which could allow significant extravasation from multiple intramedullary entrance sites. Serum drug levels arising from multiple intraosseous attempts in traumatized bone were compared with those arising from single intraosseous attempts in nontraumatized bone. We administered phenobarbital to 24 dogs randomly divided into single- (11) and multiple-attempt (13) groups. In the multiple-attempt group, we created three intramedullary insertion sites in a linear fashion and infused through only the central site. In the single-attempt group, only a single infusion site was created. Phenobarbital then was infused into the intramedullary space, and central venous phenobarbital samples were collected at one-, three-, six-, and ten-minute intervals. The single-attempt group attained significantly higher serum phenobarbital levels at each interval compared with the multiple-attempt group (P less than .0001). Therefore, to be an effective mode of therapy, it is critical to achieve single-attempt intraosseous needle placement for intraosseous infusion.

Animals↗
PubMed1984

Two-dimensional and pulsed Doppler echocardiographic abnormalities in coronary artery-pulmonary artery fistula.

We describe two patients who presented with precordial continuous murmurs which were diagnosed clinically as due to patent ductus arteriosus; however, two-dimensional echocardiographic and pulsed Doppler echocardiographic studies showed dilatation of the left main coronary artery with turbulent flow during systole in the lumen in both patients. Subsequent selective coronary angiographic studies showed bilateral coronary artery-pulmonary artery fistula in one patient and left coronary artery-pulmonary artery fistula in the other. This study illustrates that in a patient presenting with a continuous murmur which is suggestive of patent ductus arteriosus, such two-dimensional and pulsed Doppler echocardiographic findings as were seen in our patients should immediately alert the physician that he may be dealing with a case of coronary arterial fistula.

Coronary Vessels↗