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Biomedical subjects

C B Tan

Publications and source records attributed to C B Tan.

32 records · Page 2Linked to original sources
PubMed1993

HLA and Singaporean Chinese myasthenia gravis.

Chinese Singaporean myasthenia gravis (MG) patients are associated with three HLA haplotypes: Cw1 B46 DRB1*0901 DQB1*0303 DQA1*03, DRB1*14 DRB3*0202 DQB1*0503 DQA1*0101 and DRB1*1202 DRB3*0301 DQB1*0301 DQA1*0601. The B46 haplotype was associated with the total group of MG patients but in particular with those with younger onset, low antiacetylcholine receptor (anti-AchR) titres, with only ocular lesions and with normal thymuses. The DRB1*14 haplotype was associated with thymic hyperplasia, younger onset patients, with high anti-AchR titres and with generalised MG. The DRB1*1202 haplotype was associated with thymoma, older onset patients, ocular lesions, and mid to high anti-AchR titres.

Adult↗
PubMed1992

Transient oculomotor nerve synkinesis in non-Hodgkin's lymphoma.

A patient with large cell malignant lymphoma presented with transient left oculomotor nerve synkinesis, left trigeminal and abducens nerve palsies. Magnetic resonance imaging showed thickening of the oculomotor and trigeminal nerves characteristic of central nervous system lymphoma. To our knowledge, this is the first reported case of transient oculomoter nerve synkinesis in non-Hodgkin's lymphoma. The rapid onset and quick recovery of the synkinesis following 2 weeks of chemotherapy support the ephatic transmission theory.

Adult↗
PubMed1990

Nuclear third nerve palsy and somnolence due to stroke--a case report.

We describe a 40 year-old male with a ball-cage mitral valve prosthesis who suddenly developed bilateral ptosis, bilateral dilated and unreactive pupils, right third nerve palsy, bilateral failure of vertical gaze, somnolence and mild ataxia without major motor deficits. Computed Tomography (CT) revealed bilateral thalamic infarcts in the distribution of the rostral basilar artery. Infarction in this case occurred despite adequate anticoagulation. The recognition of the entity of rostral basilar artery occlusion is important as interruption of anticoagulation may be avoided.

Adult↗
PubMed1990

Persistent mutism and dysphagia of acute onset due to bilateral internal capsule infarction.

Acute mutism with paralysis of the bulbar and facial muscles following discrete bilateral internal capsular infarction is a rare stroke syndrome. We describe a 62 year-old male who suddenly became unable to speak or swallow. The paucity of facial expression and inability to voluntarily move the facial, lingual and pharyngeal muscles were persistent and contrasted with a relatively mild limb paresis which recovered. High resolution CT scan revealed infarcts in the posterior limbs of both internal capsules. It is important to recognise this stroke syndrome because of the permanence of dysarthria and dysphagia associated with it.

Bulbar Palsy, Progressive↗
PubMed1990

Acute sympathotonic orthostatic hypotension with recovery.

We describe a 30 year-old female who presented with severe orthostatic hypotension despite appropriate compensatory tachycardia on standing, following a viral infection. Clinical assessment and laboratory evaluation failed to detect other causes of her illness besides sympathotonic orthostatic hypotension. She responded to fludrocortisone and recovered completely after 3 months. We postulate that her acute reversible illness was due to a post-viral immunological response selectively affecting the alpha adrenergic receptors subserving the post-ganglionic sympathetic vasomotor fibres.

Acute Disease↗
PubMed1985

Cryptococcal meningitis.

Cryptococcosis is a systemic fungal disease and meningitis is the most serious complication. The purpose of this study is to define problems related to its diagnosis and treatment. This is a retrospective analysis of 25 patients admitted from January 1978 to December 1981. All patients had cryptococcal neoformans meningitis proven by culture of cerebrospinal fluid. One patient had a predisposing illness, being on immunosuppressant therapy after a renal transplant 2 years ago. A progressively severe headache of recent onset was the most striking presentation. Fever was frequently absent as a symptom. Cranial nerve palsies were commonly seen. Impairment of consciousness and areflexia signified a poor prognosis as all four patients who died early in the course of treatment were comatose and two of them were areflexic on admission. In newly suspected cases at least 3 separate lumbar punctures are recommended as initial smears or cultures may be negative. Cerebral CT scans were abnormal in 12 patients and those with cerebral oedema or hydrocephalus had a poorer prognosis. Combined amphotericin B and 5-fluorocytosine therapy was the treatment of choice. If there is no relapse 3 years after completion of treatment, patients are considered as cured. Positive smears may remain for years after completion of treatment and retreatment is only indicated if the cultures are positive. Twenty patients are alive today and none of them have relapsed. One patient had vasculitis of both anterior cerebral arteries as a result of cryptococcal meningitis.

Adolescent↗
PubMed1983

Nitrogen metabolism in the sheep fetus. Observations on the liver and placenta.

Ammonium ions added in large quantity disappear rapidly from the reservoir of the sheep placenta perfused in situ through the umbilical vessels. Ammonium ions are removed from the reservoir of perfused sheep fetal livers of 108-141 days of conceptual age at a rate of at least 1 mumol/min/g liver. The majority appears as urea. There is little or no change in glutamine concentration. Hepatic carbamoylphosphate synthetase I, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinase and arginase are present, even at 97 days of conceptual age, in adequate amounts to account for the observed urea production. With the exception of arginase, all levels rise with fetal age. The levels in the maternal liver are comparable with those at 106 days of conceptual age. Arginase is high in the younger fetuses, falls progressively with fetal age and is very low in the mother. It is concluded that (a) the perfused placenta is permeable to ammonia and the placenta may be able to clear ammonia from the fetal circulation at a rate comparable with that of fetal liver; (b) the fetal liver converts ammonia to urea at a rate comparable with the urea production of the fetus; (c) there is virtually no glutamine production by the fetal liver; (d) adequate amounts of the enzymes of urea synthesis are present even in the immature fetal liver to account for the total urea production of the fetus, and (e) the anomalously low arginase level in the maternal liver may conserve maternal arginine, and the high levels in the younger fetuses may be related to fetal polyamine production from maternally derived arginine.

Ammonia↗
PubMedDate not supplied

Pattern ERG: effects of reference electrode site, stimulus mode and check size.

We studied monocular pattern ERG (PERG) in 10 normal subjects and a patient with optic neuritis. No clinically significant PERG could be recorded from the occluded eye with any reference (ipsilateral ear or temple, or midfrontal), indicating that cross-contamination is not present with binocular testing. Ipsilateral temple reference minimized VEP (P100/N100) contribution to the PERG N95 which occurred with ipsilateral ear or midfrontal reference. The conclusions were confirmed by results from the patient, who had marked monocular delay of a normal amplitude P100. Twenty-four subjects were tested with monocular and binocular stimulation using an ipsilateral temple reference. There were differences in PERG latencies and amplitudes although the interside amplitude ratio showed smaller differences with binocular stimulation. Increasing check size (17, 35 and 70 min) decreased P50 and N95 latencies and increased P50 amplitude.

Adult↗
PubMedDate not supplied

Tongue deviation in acute ischaemic stroke: a study of supranuclear twelfth cranial nerve palsy in 300 stroke patients.

It is generally believed that the supranuclear innervation of the hypoglossal nucleus is bilateral and symmetrical. The aim of this work is to study the frequency and clinical characteristics of supranuclear tongue palsy in unilateral stroke. 300 patients with acute unilateral ischaemic motor strokes (excluding those in the lower brainstem) and an equal number of normal controls were studied for the presence of tongue deviation in a standardised manner. 29% of stroke patients and 5% of controls had tongue deviation (p < 0. 00001). Deviation was always to the side of the limb weakness. In patients with a history of stroke, it occurred more frequently in those with previous stroke on the contralateral side. Tongue deviation was most common in patients with clinical features of the non-lacunar stroke subtype (56%) or in those with cortical or large subcortical infarctions on brain CT scan (55 and 45%, respectively). All tongue deviations were associated with supranuclear 7th nerve palsy. Dysphagia and dysarthria occurred in 43 and 90% of patients with tongue deviation. Weakness of the arm was significantly associated with presence of tongue deviation. Tongue deviation in unilateral stroke most likely results from asymmetrical supranuclear control of the 12th cranial nerve in many individuals. The finding that it occurs relatively commonly in large (non-lacunar) infarcts and its association with dysphagia may have clinical utility.

Age Distribution↗