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Biomedical subjects

C C Lim

Publications and source records attributed to C C Lim.

At least 37 records · Page 2Linked to original sources
PubMed1999

Impaired lusitropy-frequency in the aging mouse: role of Ca(2+)-handling proteins and effects of isoproterenol.

We examined the relationship between age-associated lusitropic impairment, heart rate, and Ca(2+)-handling proteins and assessed the efficacy of increasing left ventricular (LV) relaxation via beta-adrenergic stimulation in adult and aging mouse hearts. LV function was measured in isolated, isovolumic blood-perfused hearts from adult (5 mo), old (24 mo), and senescent (34 mo) mice. Hearts were paced from 5 to 10 Hz, returned to 7 Hz, exposed to 10(-6) M isoproterenol, and paced again from 7 to 10 Hz. Age-related alterations in Na(+)/Ca(2+) exchanger (NCX), sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a), and phospholamban (PLB) levels were assessed by immunoblot. Despite preserved contractile performance, aging caused impaired lusitropy. Increased pacing caused an elevation in end-diastolic pressure that progressively worsened with age. The time constant of isovolumic pressure decay (tau) was significantly prolonged in old and senescent hearts compared with adults. Relative to adult hearts, the SERCA2a-to-PLB ratios were reduced 68 and 69%, and NCX were reduced 37 and 58% in old and senescent hearts, respectively. Isoproterenol completely reversed the age-associated lusitropic impairments. These data suggest that impaired lusitropy in aging mouse hearts is related to a decreased rate of cytosolic Ca(2+) removal and that accelerating SR Ca(2+) resequestration via beta-adrenergic stimulation can reverse this impairment.

Adrenergic beta-Agonists↗
PubMed1999

Mucocele involving the anterior clinoid process: MR and CT findings.

We report two patients with surgically proved mucoceles involving the anterior clinoid process. One patient had a mucocele of an Onodi cell and the other had a mucocele isolated to the anterior clinoid process. The MR signal was increased on both T1- and T2-weighted images in the first patient but was isointense on both sequences in the second patient, a finding that resulted in misdiagnosis. The developmental and anatomic features, as well as the diagnostic pitfalls, are discussed.

Adult↗
PubMed1999

Meningoencephalitis caused by a novel paramyxovirus: an advanced MRI case report in an emerging disease.

Eleven abattoir workers in Singapore were infected in March 1999 by an outbreak caused by the Nipah virus. This newly discovered, Hendra-like paramyxovirus causes acute infection of the CNS. We present the magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) findings in a patient suffering from acute meningoencephalitis. Multiple small white matter lesions were detected on diffusion-weighted imaging (DWI) and T2-weighted images. There were no abnormalities detected on MRS. We believe this to be the first reported MRI findings in this novel zoonotic viral disease.

Abattoirs↗
PubMed1998

Crohn's disease in the Singapore Chinese population.

Crohn's disease (CD) is rare in the Chinese population, but lately there seems to be an increasing trend of CD in the Singapore Chinese population. We carried out a retrospective study of all Chinese patients with CD seen from 1987 to 1993 at the Singapore General Hospital. All patients were regularly followed up and treated. Disease activity was defined by the Organisation Mondiale de Gastroenterologie index. We also compared our series with our first series reported in 1987 and a Western series. There were 32 patients (20 men, 12 women) giving a hospital prevalence of 26.7 per 100,000 patients compared with 3.5 per 100,000 patients in 1986. The mean age was 37.1 years (range, 19-80 years). Twelve patients had small intestinal disease, 9 had colonic disease, and 11 had both. The common presenting symptoms were bloody diarrhea (67%), abdominal pain (53%), loss of weight (47%), and fever (34%). Extraintestinal manifestations were rare. Six patients had no relapse during the follow-up period, whereas the remaining 26 patients had an average of two relapses (range, 1-5). These relapses were complicated by fistulas in 8 patients and strictures in 11 patients. Response to steroids and sulfasalazine was good in most patients. Four patients required repeated surgery despite medical treatment. The prevalence of CD appears to be increasing among the Singapore Chinese population. The clinical features are similar to those of the Western population. Most of our patients responded to standard medical therapy, but further follow-up is needed to assess their long-term clinical outcome.

Adult↗
PubMed1996

Endoscopic stenting in the management of biliary stones.

INTRODUCTION: Endoscopic sphincterotomy and stenting are established modes of treatment in the management of bile duct stones and cholangitis. It is the first choice of treatment when the patients are elderly and have other medical conditions rendering them unfit for surgery. AIMS: We studied the immediate and long-term outcome of endoscopic stenting in patients who underwent Endoscopic Retrograde Cholangiopancreatography (ERCP) for ductal stones. PATIENTS AND METHODS: From January 1990 to December 1992, 366 patients had ERCP done for biliary stone disease. Fifty-five of these patients received a 10 French biliary stent for the treatment of bile duct stones. Most of these patients (60%) had an advanced age of more than 70 years and 45% had co-existing medical conditions rendering them high risk for surgery. Ninety-one percent had stones greater than 1.2 cm in diameter and 82% had multiple stones. RESULTS: Eighty-nine percent of the patients had relief of jaundice and cholangitis resolved in 96% of the patients after stenting. None required immediate surgery after ERCP. Temporary bile drainage was achieved in 19 patients who went for surgery at a later date when they became more stable. Twenty-nine patients were on long-term follow-up for a mean period of 13 months. Nineteen patients still have their stents in place and remained well. The stents were repeatedly changed in 15 patients after an average duration of 5.5 months. Late complications were cholangitis in 2 patients and stent migration in one patient. There was no related mortality. In 5 patients, the stones have either disappeared spontaneously or become smaller and have been removed at subsequent ERCP. CONCLUSION: Endoscopic stenting is a valuable alternative to surgical bile duct exploration. It can be the definitive mode of treatment for large or multiple bile duct stones in the elderly and patients with multiple medical problems who are unfit for surgery.

Adult↗
PubMed1996

Spinal epidural non-Hodgkin's lymphoma: case reports of three patients presenting with spinal cord compression.

Spinal epidural non-Hodgkin's lymphoma is an uncommon lesion. In this report, we describe three patients with a clinical picture of acute spinal cord compression as the first presentation of malignant lymphoma. The diagnosis was not suspected pre-operatively, and plain radiographs of the spine were either normal or not specific. Neuroimaging showed evidence of extradural soft tissue mass crossing multiple vertebral segments. In the light of these radiological findings, non-Hodgkin's lymphoma should be a diagnostic consideration in the older patient without prior history of malignancy who presents with a prodrome of back pain followed by spinal cord compression.

Aged↗
PubMed1995

A survey of the use of prostitutes (commercial sex workers) by new male attenders at a genito urinary medicine clinic.

This study documents the use of prostitutes (commercial sex workers) by new male patients attending a genito urinary medicine clinic. 541 consecutive male patients completed an anonymous self-administered questionnaire. 48 (8.9%) gave a history of previous purchase of sexual services in Northern Ireland and/or elsewhere; 69% of these encounters occurred outside Northern Ireland. The largest group were single men aged 20-29 years. 87% of those who purchased services in Northern Ireland were asked by the prostitute to use a condom compared with 60% elsewhere, but there was no significant difference in actual condom use between both groups (66.7% vs 72.7%) Only 21% of patients who had purchased the services more than once used condoms consistently and 29% were willing to pay more for unprotected sexual intercourse. 40% attributed their attendance at this clinic directly or indirectly to their encounter with a prostitute. Encounters with prostitutes were often related to alcohol consumption, 88% sometimes or always purchasing these services after drinking alcohol. Despite widespread publicity at-risk behaviour involving unprotected sexual intercourse with prostitutes is not uncommon. Health education should be targeted at the young single male who travels outside Northern Ireland.

Adult↗
PubMed1995

Case selection for porcelain veneers.

The options for correction of unesthetic teeth are numerous; among these treatments, porcelain veneers have received substantial attention from the profession and patients. The increase in dental health awareness and advances in dental materials and technology, such as the acid-etching technique, improved physical properties of composite luting resin, and the use of silane coupling agents, have contributed to the success ceramic veneers enjoy today. However, no single material or technique is without its limitations. This article therefore aims to review the criteria for case selection and the limitations of porcelain veneers in restorative dentistry.

Dental Porcelain↗
PubMed1995

Marginal sealing ability of three cervical restorative systems.

The purpose of this in vitro study was to evaluate the enamel and dentinal marginal sealing ability of three different cervical restorative systems. Class V preparations were made at the cementoenamel junction of 36 freshly extracted premolars. The teeth were randomly divided into three groups of 12 and restored with either a polyacid-modified resin composite ("compomer"), resin composite, or resin-modified glass-ionomer cement. The restored teeth were stored in saline at 37 degrees C for 1 week, thermally stressed for 500 cycles, and subjected to dye penetration testing. The results showed that there was no significant difference in dentinal margin sealing ability among the three materials evaluated. When the margins were in enamel, the resin composite restorations had significantly less leakage than did compomer or resin-modified glass-ionomer cement restorations. The marginal sealing ability of all three materials was significantly poorer in dentin than in enamel.

Analysis of Variance↗
PubMed1994

Survival in patients with recurrent glioma as a measure of treatment efficacy: prognostic factors following nitrosourea chemotherapy.

The assessment of efficacy of treatment in patients with recurrent glioma is notoriously difficult, and survival is the most objective endpoint. Between 1970 and 1992, a cohort of 211 patients with recurrent glioma received nitrosourea-based chemotherapy at the time of disease progression. The median survival from the start of chemotherapy was 7 months, with 30% 1-year and 10% 2-year survival probabilities. One-year survival was 22% in 147 patients with recurrent high-grade astrocytoma, 41% in 37 patients with low-grade astrocytoma and 45% in 24 patients with oligodendroglioma. Age, histological grade and Karnofsky performance status (KPS) at recurrence were independent prognostic factors for survival on multivariate analysis. Based on patients' age, tumour grade and KPS, it was possible to define three distinct prognostic groups with 1-year survival probabilities of 60, 21 and 17% (P < 0.005). Response to chemotherapy was difficult to assess but correlated with prognostic subgroup, with highest response rate (46%) in the most favourable group and lowest (13%) in the poor prognostic group. In patients with recurrent glioma, patient and tumour parameters are the major determinants of outcome which are identical to prognostic factors at the time of primary diagnosis. They can be used to provide prognostic information for the individual patient, and to stratify patients particularly in trials assessing the efficacy of novel treatments.

Adolescent↗
PubMed1994

High resolution computed tomography of the temporal bone: preliminary experience.

High Resolution Computed Tomography (HRCT) can demonstrate the detailed anatomy and pathology of the temporal bone and is fast becoming an important imaging modality in the diagnosis and preoperative management of our local patients with temporal bone diseases. We present our experience in the usage of HRCT in temporal bone lesions in Tan Tock Seng Hospital, using 8 cases as illustration. The protocol that we used to obtain the images is described. We also give an overview of those clinical conditions whereby HRCT can provide information which will help surgeons in the management of their patients. These clinical conditions are hearing loss, external auditory canal atresia, middle ear inflammation/cholesteatoma, temporal bone trauma, pulsatile tinnitus and vascular tympanic membrane.

Adult↗
PubMed1994

Role of ERCP in the management of bile duct lesions post bile duct surgery.

INTRODUCTION: Therapeutic Endoscopic Retrograde Cholangio-Pancreatography (ERCP) is an established mode of treatment for bile duct lesions. AIM: This paper reviews the role of ERCP in the management of bile duct lesions developing after biliary surgery. PATIENTS AND METHODS: Of the 894 ERCPs performed in our department between January 1990 and May 1992, 23 (13 female, 10 male) were for patients with post-operative bile duct lesions. The mean age of these 23 patients was 59 years (range 38-91 years). The previous biliary surgical procedures were conventional cholecystectomy (n = 19), laparoscopic cholecystectomy (n = 3) and a cholecystectomy with choledochojejunostomy. Associated medical conditions of ischaemic heart disease, unstable angina, hypertensive heart disease, chronic obstructive airway disease and hepatitis B cirrhosis were present in 7 of these patients. RESULTS: Ten patients had benign biliary strictures. Endoscopic stenting (with one or 2 stents) was successful in 9. The strictures reopened in 2 patients after a total stenting duration of 12 and 18 months respectively. Four patients had biliary leakages that were successfully treated with stenting. Two patients had spontaneous sealing of biliary leak at 3 and 6 months respectively. Nine patients had retained stones (7 with solitary stone, 2 with multiple stones) that were successfully removed with Dormia basket after sphincterotomy. Complications were few and manageable. CONCLUSIONS: Therapeutic ERCP is safe and effective. It is a useful adjunct in the management of patients with post-operative biliary lesions.

Adult↗
PubMed1993

A follow up study of patients discharged from the Criminal Procedure Code.

Eighty-six male psychiatric patients discharged from the Criminal Procedure Code over a 5-year period were studied to determine their social, occupational and clinical outcome. The majority were young, single Chinese who had received little education and had suffered from schizophrenia. More than half had been hospitalised for up to 5 years. On discharge many were living with their relatives, 83% were working, 60% were socially isolated and about half were asymptomatic. Factors associated with their outcome were examined.

Adult↗
PubMed1992

The effects of hematocrit, shear rate, and turbulence on ultrasonic Doppler spectrum from blood.

Previous studies of ultrasonic scattering properties of blood using a pulse-echo experimental arrangement show that ultrasonic backscatter from blood is influenced by a number of factors including hematocrit, shear rate, and the nature of flow (J. Acoust. Soc. Amer., vol. 75, p. 1265, 1984 and J. Acoust. Soc. Amer., vol. 84, p. 1, 1988). Since the Doppler frequency spectrum from a Doppler flowmeter is derived from echoes backscattered by red blood cells in the flowing blood, it is also undoubtedly a function of these parameters. The effects of these parameters on Doppler spectrum from blood have been investigated using a pulsed Doppler flowmeter. The results agree well with those obtained in previous studies. One important conclusion of this study is that the assumption that the Doppler spectral power density at a frequency in Doppler spectrum is linearly proportional to the number of red cells flowing at that velocity used in many theoretical models developed to explain the Doppler phenomenon may be erroneous. An alternative is proposed. It is shown that conclusions derived from these theoretical models would remain valid by making this assumption.

Animals↗
PubMed1991

Personality, disability and acne in college students.

The relationship between acne, personality and disability was examined in a sample of 101 junior college students in Singapore. The clinical severity of their acne was assessed using a Acne Severity Grading Scale. The disability as perceived by the individual, was evaluated using the Acne Disability Index. Our data showed that there was no difference in personality, assessed by Eysenck Personality Questionnaire, between students with mild acne (Grades 0 and 2) and those with severe acne (Grades 4, 6 and 8). Personality influences the individual's perception of disability. Students with acne who were concerned about their facial appearance were more emotional and less tough-minded than those who were not. Otherwise, there was little disability resulting from the disease.

Acne Vulgaris↗
PubMed1988

Sterilisation patterns in dental practices in Singapore.

A survey to find out the standard of sterilisation of dental equipment was conducted via a questionnaire sent out to all Division I dental surgeons in Singapore. Questions asked determined the main methods of sterilisation/disinfection of hand instruments, air rotor and air motor handpieces, burs, salivary ejectors, ultrasonic scaling tips, and the use of disposable needles, local anesthetic, carpules, and gloves. Results indicated that while most respondents sterilised or disinfected various instruments, there was an apparent misconception that sterilisation and disinfection were the same thing. The majority used boiling with water or cold chemical disinfection. Most respondents were willing to treat patients with known histories of hepatitis B but would refer patients with histories of Acquired Immune Deficiency Syndrome (AIDS).

Acquired Immunodeficiency Syndrome↗