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Biomedical subjects

C T Tan

Publications and source records attributed to C T Tan.

At least 91 records · Page 5Linked to original sources
PubMed1992

Neuroleptic malignant syndrome in Malaysia: a university hospital experience.

The neuroleptic malignant syndrome (NMS) is a potentially fatal complication of antipsychotic therapy. A retrospective study of nine patients seen over six years at the University Hospital, Kuala Lumpur (UHKL), is described. The estimated annualised incidence was 1.2 per 1000 in-patients with psychosis. No ethnic difference was detected. Clinical features were similar to experiences elsewhere, with wide variability seen in the severity of illness. The neuroleptic drugs implicated were haloperidol, trifluoperazine, chlorpromazine, fluphenazine and clopenthixol. Treatment consisted of withdrawal of offending drugs and supportive measures. Specific therapy was given to five patients. There was one death. At follow-up no deterioration was detected. A different neuroleptic drug was successfully re-introduced in four patients. In view of the wide usage of major tranquillizers, a high degree of clinical awareness of this serious complication is necessary for early diagnosis to reduce morbidity and mortality.

Adolescent↗
PubMed1992

Evoked response study among Malaysian multiple sclerosis patients.

A study of visual evoked potential (VEP), brainstem evoked potential (BAEP) and median nerve somatosensory evoked potential (SSEP) in 26 Malaysian patients with clinically definite Multiple Sclerosis (MS). This study showed an overall high rate of abnormality, with 85% of patients for VEP, 31% for BAEP and 65% for median nerve SSEP. The rate of abnormality was particularly high for patients who were symptomatic, reaching 100% of patients for VEP, 50% of patients in BAEP, 83% of nerves for median nerve SSEP. The rate of abnormality among those who were asymptomatic was lower, varying from 32% of eyes in VEP, 27% of patients in BAEP and 31% of nerves in median nerve SSEP. Three out of 10 patients with optic spinal form of MS have abnormal BAEP. These show the usefulness of the evoked potential studies in confirming the clinical lesions as well as demonstrating subclinical involvement. The rate of abnormal evoked responses for the asymptomatic patients in this study is generally lower than that published elsewhere.

Adult↗
PubMed1992

Comminuted intra-articular fracture of the distal radius--results of early open reduction and internal fixation.

Comminuted intra-articular fracture of the distal radius remains a challenging problem. This article reviews the results of 15 consecutive cases which were treated with open reduction and internal fixation with T-plate after failing to achieve articular congruency with closed reduction. The follow-up ranges from 20 months to 28 months. In thirteen cases, articular congruency was restored. However, 4 of these 13 cases later lost some of the articular congruency. This suggests the need for supplementary bone grafting. Reduction of the extra-articular portion of distal radius was generally well maintained. There was an average of 2.4 mm loss in styloid height, an increase of 1.2 mm in ulnar variance and loss of 12.5 degrees of volar tilt. Seven patients (46%) were completely pain-free, with the remaining 8 patients (53%) experiencing mild pain associated with forceful activities involving the wrist. All patients achieved a functional range of motion. Grip strength averaged 81% of the uninjured side. Of the 12 patients who were engaged in active employment, 10 returned to their previous job within 4 months of injury (average 8.5 weeks). The only complication in this series was the development of reflex sympathetic dystrophy in a 68-year-old housewife. We recommend open reduction and internal fixation if closed reduction fails to achieve articular congruency in comminuted distal radius fractures.

Adult↗
PubMed1992

Giant cell tumours of the sacrum.

Giant Cell Tumours (GCT) of the Bone is one of the commoner primary bone tumours. Although considered a benign tumour, it does occasionally metastasize to the lungs. Treatment modalities vary according to the surgical staging and the site of the tumour. Treatment is further complicated when the tumour occurs in difficult locations like the sacrum. The paper includes a review of literature into treatment options and the presentation of 3 patients with sacral GCTs, one of which also has multiple pulmonary metastases from a "benign" giant cell tumour.

Adolescent↗
PubMed1991

Cardiac toxicity 4 to 20 years after completing anthracycline therapy.

OBJECTIVE: --To assess the cardiac status of long-term survivors of pediatric malignancies who received chemotherapy, including anthracyclines. DESIGN AND METHOD: -Patients were evaluated by echocardiogram from 4 to 20 years (median, 7 years) after completion of anthracyclines, with prospective and retrospective analysis. PATIENTS: --The consecutive sample of 201 patients had received a total anthracycline dose of 200 to 1275 mg/m2 (median, 450 mg/m2), and 51 patients had mediastinal radiotherapy. MAIN OUTCOME MEASURES: --The overall incidence and severity of abnormal systolic cardiac function were determined for the entire cohort. Risk factors of total anthracycline dose, mediastinal radiotherapy, age during treatment, and length of follow-up were examined. RESULTS: --Twenty-three percent (47/201) of the cohort had abnormal cardiac function on noninvasive testing at long-term follow-up. Correlation between total cumulative dose, length of follow-up, and mediastinal irradiation with incidence of abnormalities was significant. Fifty-six patients were followed up for 10 years or more (median, 12 years), with a median anthracycline dose of 495 mg/m2. Thirty-eight percent (21/56) of these patients, compared with 18% (26/145) of patients evaluated after less than 10 years, had abnormal findings. Sixty-three percent of patients followed up for 10 years or more after receiving 500 mg/m2 or more of anthracyclines had abnormal findings. Nine of 201 patients had late symptoms, including cardiac failure and dysrhythmia, and three patients died suddenly. Microscopic examination of the myocardium on biopsy and autopsy revealed fibrosis. CONCLUSION: --The 23% incidence of late cardiac abnormalities warrants continued evaluation of patients after anthracyclines to guide patient care and the design of future chemotherapeutic protocols.

Adolescent↗
PubMed1991

Characterization of cDNA and genomic clones encoding 3-hydroxy-3-methylglutaryl-coenzyme A reductase from Hevea brasiliensis.

Hevea brasiliensis is the major producer of natural rubber which is cis-1,4-polyisoprene. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) is involved in the biosynthesis of rubber and other plant products. We have used a hamster HMGR cDNA clone as a heterologous hybridization probe to isolate and characterize cDNA and genomic clones of HMGR from H. brasiliensis. Sequence analysis revealed that these clones fall into two different classes, HMGR1 and HMGR2. Comparison of the two classes shows 86% nucleotide sequence homology and 95% amino acid homology. The carboxy-termini of Hevea HMGRs are highly homologous to those of hamster, yeast and Arabidopsis HMGR. The amino-terminus of Hevea HMGR contains two potential membrane-spanning domains as in Arabidopsis HMGR while seven such domains are found in the HMGRs of other organisms. The apparent molecular mass of Hevea HMGR was estimated in western blot analysis to be 59 kDa. Northern blot analysis indicated that the HMGR1 transcript of 2.4 kb is more highly-expressed in laticifer than in leaf. Genomic Southern analysis using 3'-end cDNA probes indicates the presence of at least two HMGR genes in Hevea.

Amino Acid Sequence↗
PubMed1991

CT scan changes in multiple sclerosis among Malaysian patients.

A study of 12 patients with clinically definite multiple sclerosis (CDMS) using high dose infusion CT showed overall abnormality of 75% with an average of 2.5 lesions per patient. 75% of the patients showed abnormality of the cerebrum, mostly asymptomatic. The main changes were ventricular dilatation and asymmetry, isolated or generalized cerebral atrophy, areas of low attenuation mainly in the deeper parts of the cerebrum and the peri-ventricular area. 25% of the patients showed changes in the brainstem and none was seen in the cerebellum. The abnormality was more florid in patients with clinically disseminated forms of the disease. The study demonstrated that asymptomatic cerebral involvement is common among Asian patients with MS and CT is a useful tool in the overall assessment and diagnosis of Asian MS patients.

Adult↗
PubMed1989

Diaziquone and 2,2'-anhydro-arabinosyl-5-fluorocytosine for the treatment of children with relapsed or refractory acute nonlymphoblastic leukemia.

The authors treated 30 patients ages 1 to 19 with relapsed or refractory acute non-lymphoblastic leukemia (ANLL) with the combination of diaziquone (AZQ) and 2,2'-anhydro-arabinosyl-5-fluorocytosine (AAFC) intravenously in two dose schedules. The first 12 patients were treated with 19 courses of AZQ 30 mg/m2 X 3 days and AAFC 600 mg/m2/dose every 12 hours X 10 doses. An additional patient was treated with three courses at 80% of the above doses. Hepatic toxicity was National Cancer Institute Grade III in eight of 22 and Grade IV in one of 22 courses. Infectious complications were severe in all patients, including responders. One patient achieved a complete remission and one a partial remission; the latter died with marrow aplasia after a second course. Altogether three patients developed profound aplasia and died before marrow recovery. The authors treated a second group of 17 patients with AZQ 22.5 mg/m2/day X 3 days and AAFC 450 mg/m2/dose every 12 hours X 10 doses. Three patients achieved a complete remission and one patient a partial remission for 3, 4, 9, and 9 months, respectively. The remainder had progressive disease or no response. All patients developed profound myelosuppression but no toxic deaths occurred. Hepatic toxicity was reduced. Therapy induced cytoreduction of bone marrow was determined by flow cytometry in ten patients; none of these patients responded during the interval studied. Although AZQ and AAFC are active in childhood ANLL with acceptable toxicity, the combination does not appear more active than AZQ used alone. Future studies should define the role of AZQ in combination with other agents.

Adolescent↗
PubMed1989

Subdural spinal lipoma with posterior fossa extension.

A case is described of subdural spinal lipoma with posterior fossa extension and the world literature is reviewed. A high proportion of high cervical lipomas extend into the posterior cranial fossa. Many cases were probably missed in the pre-computed tomography era. Those cases with posterior fossa growth are more likely to be found in infants or those cases with symptoms dating from birth; most present with quadriparesis. All cases of high cervical lipoma demonstrated by myelography should be submitted to brain computed tomography in order to exclude posterior fossa extension and demonstrate the presence of hydrocephalus.

Adolescent↗
PubMed1989

Prognosis of patients who present with an episode of myelopathy of unknown origin in Malaysia: a retrospective study of 52 patients.

Fifty-four per cent of 52 patients presenting to the University of Malaya Medical Centre with a myelopathy for which appropriate investigations uncovered no definite etiology, subsequently developed clinically definite or probable multiple sclerosis. In the subgroup of patients with a presentation indicative of acute/subacute transverse myelopathy, 14 or 52% also went on to develop clinically definite or probable multiple sclerosis, a far higher proportion than previously recorded in the literature. This finding is probably a further manifestation of racial difference in the behaviour of multiple sclerosis. For the group as a whole, the only factor which appeared to be associated with an increased risk of developing multiple sclerosis was female sex; 67% of 33 female patients went on to develop multiple sclerosis after a mean follow-up period of 5.5 years. Other factors such as age of onset, racial composition, level of spinal cord involvement, presence of fever and CSF finding were found not to be important.

Adolescent↗
PubMed1989

Automatic external rotation during passive glenohumeral abduction.

A study of human cadaveric glenohumeral joints was undertaken to investigate the mechanism of external rotation during abduction. Previously explored extra-articular influences such as the coracoacromial arch and the rotator cuff muscles were removed from the specimens. A specially designed device was used to measure abduction in the scapular plane as well as any rotation of the humerus. The findings show that external rotation is a consistent feature of passive abduction in the plane of the scapula and could take place in the absence of extra-articular influences. The mechanism appears to lie either in the nature of the capsule or of the articular contours. A role for the intra-articular part of the long head of the biceps cannot be excluded.

Aged↗
PubMed1988

Second malignancies after childhood Hodgkin's disease. The Memorial Sloan-Kettering Cancer Center experience.

A review of the Memorial Sloan-Kettering Cancer Center experience with second malignancies (SM) after childhood Hodgkin's Disease (HD) identified 17 SM in 320 patients who survived more than 1 year from, and were 15 years old or younger at the time of, HD diagnosis (1949 to 1983). Of 254 previously untreated patients, 12 SM were noticed as compared with 0.606 expected on the basis of rates in the general pediatric population (relative risk, 19.8; 95% confidence interval, 10.2 to 34.6). For patients who received multi-agent chemotherapy, the cumulative probability of developing acute nonlymphocytic leukemia (ANLL) or bone sarcoma was 6.2% and 5.5%, respectively, at 10 years from the initiation of therapy; the cumulative risk of all SM in this group reached 18.7% at 15 years. For patients who received radiation alone or with single-agent chemotherapy, the cumulative risk of SM rose from 0% at 10 years and 2% at 15 years, to 10.7% at 25 years from the initiation of treatment. The risk of ANLL after childhood HD was highest in the first 5 to 10 years after combined modality treatment, and aggressive forms of NHL were associated with excessive immunosuppression. Bone sarcomas predominated in solid SM in the first decade after HD treatment, whereas "adult-type" cancers, for example, breast and colon carcinomas, were more delayed. Our findings, supported by a literature review, point to a therapy-related enhanced risk of approximately age-appropriate solid SM. This possibility mandates careful surveillance of long-term survivors of childhood HD.

Adolescent↗
PubMed1988

Multiple sclerosis in Malaysia.

Thirty consecutive patients from peninsular Malaysia with clinically definite multiple sclerosis were studied; 80% were ethnic Chinese, with a female-male ratio of 5:1. The average age at onset was 29.7 years, with one relapse average every 1.9 years. Optic-spinal recurrence was the most common clinical pattern of the disease, accounting for 63.3% (19/30) of the cases. All the patients had spinal cord involvement sometime during the course of the illness. The mortality was high at 36.7% (11/30), with an average duration of symptoms of 7.6 years. There was characteristic severe residual visual and motor disability. At the time of the last examination, 12 patients had bilateral optic atrophy with blindness or severe visual acuity impairment. Sixteen patients were bedridden or confined to a wheelchair. The severe motor disability reflected the severe spinal cord involvement. It was the main factor that accounted for the high mortality. The cerebral, cerebellar, and brain-stem involvements were, however, generally transient. None of the patients' had a family history of similar illness despite the average sibling size of six. There was no example of Devic's disease. The clinical pattern was closest to those patients who presented from Taiwan.

Adult↗
PubMed1988

Intracranial hypertension causing visual failure in cryptococcus meningitis.

Thirty four patients with cryptococcal meningitis seen in the University of Malaya medical centre since 1980 were reviewed. Eleven patients had bilateral papilloedema and visual impairment but eventually survived. Seven patients had intensive aggressive measures, including shunting to reduce intracranial hypertension irrespective of ventricular size shown in CT scan, and showed substantial improvement in vision. It is concluded that papilloedema and visual failure in cryptococcal meningitis reflects raised intracranial pressure and that this should be treated vigorously.

Adolescent↗