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Biomedical subjects

C T Tan

Publications and source records attributed to C T Tan.

At least 73 records · Page 4Linked to original sources
PubMed1995

A cDNA clone encoding Brassica calmodulin.

A 834 bp cDNA encoding calmodulin (CaM) has been isolated from Brassica juncea. On Northern analysis this cDNA hybridises this cDNA to mRNAs of about 0.9 kb in leaf, silique and peduncle. Genomic Southern analysis indicates the presence of a CaM multigene family in Brassica juncea. Comparison of the predicted amino acid sequence of Brassica CaM with that of Arabidopsis CaM ACaM-2 and ACaM-3 showed 100% homology, which is not unusual, since both plants belong to the family Cruciferae. In situ hybridisation studies on Brassica seedlings using a digoxigenin-labelled RNA probe showed that high levels of CaM mRNA were detected in the leaf primordia and the shoot apical meristem, and to a lesser degree, in the zone of root elongation of the root tip. The occurrence of a higher rate of cell division and growth in these regions than its surrounding tissue may possibly be related to higher levels of CaM mRNA.

Amino Acid Sequence↗
PubMed1995

Fluoxetine in the treatment of depression in Asian (Chinese and Indian) patients in Singapore.

The aim of this paper is to study the efficacy and side-effects of fluoxetine. Fluoxetine is a specific serotonin reuptake inhibitor. Nineteen Asian (Chinese and Indian) patients who satisfied the DSM-3R criteria for major depressive episode were treated with fluoxetine 20 mg daily for 12 weeks. They were monitored two weekly. The results showed that during the period of treatment there was significant improvement in depressive symptoms and no serious side-effects. There were no significant changes in weight, temperature, blood pressure and pulse rate throughout the 12 weeks. This study showed that fluoxetine was well-tolerated and relieved the symptoms of depression effectively. Most of the results are supported by other studies.

Adult↗
PubMed1994

Pharmacologic-guided trial of sequential methotrexate and thioguanine in children with advanced malignancies.

PURPOSE: Based on in vitro studies that have shown synergistic effects of sequential administration of methotrexate (MTX) and thioguanine (6-TG), we conducted a pharmacologically guided trial of sequential MTX and 6-TG to determine the following: (1) the maximum-tolerated dose (MTD) of 6-TG; (2) the nature of the dose-limiting toxicity; and (3) the modulation effect of MTX on 6-TG given by this sequence and schedule. PATIENTS AND METHODS: Thirty-one children with advanced malignancies (acute leukemia, n = 10; lymphoma n = 10; and solid tumors, n = 11) were treated weekly for 3 weeks with a 2-week rest; treatment consisted of a fixed dose of MTX (30 mg/m2 over 24 hours) followed by a 2-hour infusion of 6-TG in escalating doses. RESULTS: Measurement of plasma MTX, 6-TG, and mononuclear 5-phosphoribosyl-1-pyrophosphate (PRPP) levels indicates that the desired biochemical modulation and serum levels were achieved. Nonhematologic toxicities were mild and the dose-limiting toxicity was bone marrow depression. A 300-mg/m2 dose of 6-TG with MTX is considered the MTD. Responses were noted in patients with lymphoma. CONCLUSION: Encouraging antitumor effects were produced with this regimen in heavily pretreated patients with lymphoma, particularly Hodgkin's disease (HD). The durations of responses were 17, 13+, 12, 9, and 7+ months. A phase II trial of the MTX/6-TG combination is warranted for the treatment of relapsed lymphoma.

Adolescent↗
PubMed1994

An in vivo canine model for the study of phonation physiology by midbrain stimulation.

A versatile in vivo canine model is indispensable in studying the phonation function of the larynx. In this study, we attempted to build an in vivo phonation model in anesthetized dogs using stereotaxic electrical stimulation at a specific area in the midbrain. In each of the eight animals in this experiment, evoked phonation was successfully elicited by stimulating sites in the area ranging from 9 to 11 mm anterior, 3 to 5 mm lateral and 5 to 16 mm dorsal to the ear bar zero. This area was at the lateral border of the periaqueductal gray in the midbrain. The evoked-phonation process involved electrical stimulation of sites in this area, resulting in consistent responses by respiratory and laryngeal musculature accompanied by phonation. The evoked phonation could be consistently repeated. Different pitches of phonation were elicited by slightly moving the stimulation spots in this area. During evoked phonation, the subglottic aerodynamic power and individual laryngeal muscle action could be modified to study the effects of a single factor on the phonation process. The neuromuscular action for the control of phonation and the mechanical properties of the vocal folds can be investigated using an in vivo canine model.

Animals↗
PubMed1994

Malaysian children with: "benign epilepsy of childhood with centrotemporal spikes".

Benign epilepsy of childhood with centrotemporal spikes (BECT) was studied in Malaysian children, and was observed in Chinese, Malay and Indian children in the ratio 10:6:5. There were 12 boys and 9 girls. Fit frequency varied from almost daily to a single fit. The age of onset ranged from 2-13 years and BECT was not noted in any child over 13 years old. There was a strong circadian rhythm and fits occurred mainly in sleep. Generalised seizures were more common than partial seizures. During the 3-year study from April 1989 to April 1992, 21 children with BECT were identified from the EEG records done at the University Hospital and it was found that this genetic epilepsy which is autosomal dominant with age dependent penetrance occurs in approximately 4.8% of our epileptic children. In addition there were 3 children in whom petit mal co-existed with a BECT EEG trait.

Adolescent↗
PubMed1994

Wilson's disease--a review of cases at University Hospital, Kuala Lumpur.

The clinical course of 18 patients with Wilson's disease is reported. There were 13 males and five females of whom one is Malay. The prevalence of Wilson's disease in Malaysia is probably the same as elsewhere. Being a genetic syndrome, the genetic carrier rate for Wilson's disease is probably lower amongst the Malays. At diagnosis, the clinical signs were predominantly hepatic in 10 patients, neurological in five patients with three asymptomatic cases. All patients were commenced on penicillamine but poor compliance was observed in many patients. Two patients defaulted follow-up and seven patients died. Out of the nine surviving patients, only four are well with no clinical symptoms.

Adolescent↗
PubMed1994

The hot bath test among Malaysian multiple sclerosis patients.

This is a study of 13 Malaysian patients with clinically definite Multiple sclerosis (MS) subjected to a hot bath test with VEPs, BAEPs, median nerve SSEPs before and after heating. Five patients (38%) developed neurological changes with the rise in body temperature. There was an average of 0.46 new sign per patient. Four patients had motor disturbances attributed mainly to aggravation of spinal cord dysfunction. Two patients had additional visual deterioration, one patient has associated VEP change. This study shows that though Uhthoff's phenomenon has not been noted in the reports of Asian MS patients, when subjected to rigorous testing, Asian MS patients also show sensitivity to body temperature change. However, the percentage of positivity of the hot bath test is much lower than that reported for Caucasians. Thus this study shows further differences between Asian and Caucasian MS patients.

Adult↗
PubMed1993

Juvenile myoclonic epilepsy--a report of 11 patients at the University Hospital, Kuala Lumpur.

This is a report on 11 cases of Juvenile Myoclonic Epilepsy (JME) from the University Hospital, Kuala Lumpur, all of whom were diagnosed in the last one and a half years. This genetic syndrome is seen in all the three main racial groups: Chinese, Malays and Indians. It accounts for 2% of the epilepsy patients seen at the neurology clinic. Lack of awareness is the main hindrance to diagnosis.

Adolescent↗
PubMed1993

Antiphospholipid antibodies and stroke in the young--a study of three cases.

Cerebral infarction in the young is likely to be non-atheromatous. While in previous studies no cause has been found in 40% to 50% of patients, an increasing role for haemorheological factors is becoming apparent. Among these, an association between antiphospholipid antibodies (aPLs) and ischaemic cerebrovascular disease is now well-recognised. This entity has not been previously reported in Malaysian patients. In a study of 80 patients with stroke below the age of 50 years who were seen at the University Hospital, Kuala Lumpur, between January 1982 and May 1992, 3 patients with ischaemic cerebral infarction were found to have aPLs. aPLs was detected using ELISA method for anticardiolipin antibodies (aCLs), and presence of lupus anticoagulant (LA) was established by kaolin clotting time, thromboplastin inhibition test and platelet neutralisation procedure. Only 1 patient had active systemic lupus erythematous. Cerebrovascular events were recurrent in one of the 2 non-lupus patients. aPL-related stroke should be considered in young patients who have cerebral ischaemia occurring without obvious cause. More cases are likely to emerge in Malaysia with active screening.

Adolescent↗
PubMed1993

The hypochondriacal patient.

Until recently, hypochondriasis received relatively little attention from clinical investigators. The epidemiology is largely unknown. The numerous theories on the aetiology cannot explain the psychopathology. Recent interest and attempts at operationally defining the syndrome have resulted in some progress in the recognition and treatment of the hypochondriacal patient. The physician's reaction is highlighted as an important factor that contributes to the initiation and maintenance of this difficult condition.

Humans↗
PubMed1993

Sudden death due to incarcerated Bochdalek hernia in an adult.

Bochdalek hernias presenting in adulthood are rare occurrences. They present commonly as acute surgical emergencies. A case of sudden death due to perforation of gastric ulcer in an incarcerated Bochdalek hernia is reported. This has not been previously documented. Recent literature on the subject is also reviewed.

Adult↗
PubMed1992

Three genes encode 3-hydroxy-3-methylglutaryl-coenzyme A reductase in Hevea brasiliensis: hmg1 and hmg3 are differentially expressed.

The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) catalyses an important step in isoprenoid biosynthesis in plants. In Hevea brasiliensis, HMGR is encoded by a small gene family comprised of three members, hmg1, hmg2 and hmg3. We have previously described hmg1 and hmg2 (Plant Mol Biol 16: 567-577, 1991). Here we report the isolation and characterization of hmg3 genomic and cDNA clones. In comparison to hmg1 which is more highly expressed in laticifers than in leaves, the level of hmg3 mRNA level is equally abundant in laticifers and leaves. In situ hybridization experiments showed that the expression of hmg3 is not cell-type specific while hmg1 is expressed predominantly in the laticifers. Primer-extension experiments using laticifer RNA showed that hmg1 is induced by ethylene while hmg3 expression remains constitutive. The hmg3 promoter, like the promoters of most housekeeping genes, lacks a TATA box. Our results suggest that hmg1 is likely to encode the enzyme involved in rubber biosynthesis while hmg3 is possibly involved in isoprenoid biosynthesis of a housekeeping nature.

Amino Acid Sequence↗
PubMed1992

Coronary artery bypass surgery in young patients.

Coronary atherosclerosis is being increasingly observed in young patients. However results of surgery in such patients have so far been disappointing both in terms of operative mortality, symptomatic relief and long-term survival. Reasons given for this include the increased prevalence of risk factors in young patients and a higher incidence of graft occlusion. In the treatment of Asian patients, a further negative factor is the belief that coronary artery disease is more often diffuse and the vessels smaller. Between January 1987 and May 1991, a total of 66 patients under the age of 45 years at the time of surgery had coronary artery bypass grafting performed. The demographic, clinical, angiographic and operative data were analysed. Eighty-nine per cent of the patients were male and their racial distribution was 63% Chinese, 8% Malays, 26% Indians and 3% Others. Their mean age was 40.8 years. The presence of risk factors was high: 45.6% had hypertension; 34.8% were smokers; 21.2% had diabetes mellitus; and 12.1% had hyperlipidaemia. The main indication in these patients was either angina or a previous myocardial infarction (53%). There were no patients with perioperative infarction diagnosed by the presence of new Q wave. There was no hospital death. The stay of the patients ranged from 6 to 28 days with a mean of 10 days. Follow-up ranged from 3 to 54 months. There were no late deaths. It was concluded that there is a high incidence of risk factors among young patients with coronary artery disease, which follows the pattern of many other studies. The operative risk in these patients is low and morbidity is minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Valvular heart disease in four patients with Maroteaux-Lamy syndrome.

BACKGROUND: Maroteaux-Lamy syndrome is a lysosomal storage disease of mucopolysaccharide metabolism (MPS type VI) that may involve the mitral and aortic valves. Affected patients have other skeletal and oropharyngeal malformations that complicate anesthetic and surgical management. METHODS AND RESULTS: The present report describes the clinical, echocardiographic, and pathological findings in four patients with Maroteaux-Lamy syndrome. Two of three siblings underwent successful double-valve replacement for aortic and mitral valve stenoses. The third sibling, whose aortic and mitral valves were thick and fibrotic, died from septicemia after hip surgery. A fourth, unrelated patient also had successful double-valve replacement. CONCLUSIONS: Our experience emphasizes the potential difficulties in preoperative assessment and surgical treatment as well as the unique problems related to airway management in patients with this syndrome.

Adult↗