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Biomedical subjects

Y L Yu

Publications and source records attributed to Y L Yu.

At least 19 recordsLinked to original sources
PubMed1992

An acidic fibroblast growth factor protein generated by alternate splicing acts like an antagonist.

Polymerase chain reaction amplification of cDNA for acidic fibroblast growth factor in several lines of cultured human cells revealed two forms of mRNA. The novel smaller mRNA lacks the entire second coding exon of the acidic fibroblast growth factor gene, whereas the previously identified mRNA consists of three coding exons. The truncated variant of acidic fibroblast growth factor (aFGF') is only 60 amino acids long with an apparent molecular mass of 6.7 kD on sodium dodecyl sulfate gels in contrast to 18 kD for the full-length acidic fibroblast growth factor. aFGF' elicits only minimal fibroblast proliferation and antagonizes the effects of acidic fibroblast growth factor when added exogenously to or when coexpressed with aFGF in BALB/c/3T3 fibroblasts. Thus, the truncated variant of acidic fibroblast growth factor may provide fibroblasts with a unique mechanism for endogenous regulation of their responses to acidic fibroblast growth factor.

Amino Acid Sequence↗
PubMed1992

Treatment of idiopathic hemifacial spasm with botulinum toxin.

Twelve patients with idiopathic hemifacial spasm received treatment with botulinum toxin A over a period of 18 months. Of 76 treatments given, most (94.7%) led to successful relief of eyelid spasms and all treatments were successful for perioral and lower facial muscle spasms. An average dose of 9.3 units of toxin per session was given to produce a mean interval of relief of 10.8 weeks. Blepharoptosis was the only ocular side effect; it was mild, reversible and occurred in 2 patients. However, lower facial palsy was frequent (9 patients); it was mild to moderate in severity but only partially reversible in 8 patients. Dosage for lower facial muscles should therefore be reduced.

Adult↗
PubMed1992

Myasthenia gravis in Hong Kong Chinese. 1. Epidemiology and adult disease.

A territory-wide study of myasthenia gravis (MG) was conducted in Hong Kong. Two hundred and sixty-two Chinese patients (159 adult and 103 paediatric onset) were identified, corresponding to a point prevalence and period prevalence of 53.5 and 62.2 per million respectively, and an average annual incidence of 4.0 per million population. Nine patients died, 7 from MG, giving a case fatality rate of 0.027. Female predominance was present in the whole group of patients (female to male ratio 1.6:1) and in those with adult disease (ratio 2.1:1), but not in those with onset in childhood (ration 1.1:1). Onset of disease was most common in the first 3 decades of life, and became less common in subsequent decades. Juvenile onset MG occurred in 39.3% of patients and restricted ocular MG in 47.9%. Familial occurrence was found in 5 patients. In the 159 adult onset patients, ocular disease was most common (32.7%), followed by mild generalised (29.6%), moderately severe generalised (24.5%), fulminating (11.9%) and late severe disease (1.3%). The mean age of onset of symptoms was 36.7 years. The symptomatology was similar to that of Caucasoid populations. Autoimmune thyroid disease was the commonest associated disease, and the incidence of thymoma among thymic abnormalities was high at 38%.

Adolescent↗
PubMed1992

Vascular pseudoparkinsonism.

Vascular pseudoparkinsonism may be confused with idiopathic Parkinson's disease. Patients may be unnecessarily treated with anti-parkinsonian drugs while their underlying vascular disease is ignored. We investigated 250 parkinsonian patients seen in our Movement Disorders Clinic for a possible vascular etiology. After excluding those with a known secondary cause such as drug-induced parkinsonism, progressive supranuclear palsy, multiple system atrophy and hyperparathyroidism, brain computed tomography and/or magnetic resonance imaging were performed on those who showed poor or no response to levodopa. In those with an ischemic lesion demonstrated on neuroimaging, anti-parkinsonian drugs were stopped and the patients were reassessed. Eleven patients (4.4%) had ischemic brain lesions accounting for their parkinsonism. All were initially diagnosed as Parkinson's disease because of the prominence of bradykinesia and rigidity. Gait disturbance was also common, but resting tremor was distinctly absent. Three anatomical patterns with different prognosis were identified. Three patients with basal ganglia lacunar infarct recovered spontaneously, three with frontal lobe infarcts remained static and five with periventricular and deep subcortical white matter lesions had progressive deterioration. Autopsy in one patient confirmed bilateral frontal lobe watershed infarcts and the absence of brain stem Lewy bodies. Parkinsonian patients with poor or no response to levodopa therapy should be investigated for a vascular etiology.

Aged↗
PubMed1992

Myasthenia gravis in Hong Kong Chinese. 2. Paediatric disease.

In a study covering 85% of the population of Hong Kong, 39% of all myasthenia gravis (MG) patients, i.e. 103 individuals (54 girls and 49 boys) were found to have had MG with onset before puberty. Two patients had transient neonatal MG, 20 had early onset juvenile MG and 81 had late onset juvenile MG. Restricted ocular MG occurred in 71% of patients and the remainder had generalised MG. The median age at onset was 4 years. Complete remission occurred in 34 patients (34%), a good response in 14 (14%), and fair response in 32 (32%). The clinical course remained static in 16 patients (16%) and 3 patients deteriorated. Two patients died, 1 with myasthenic crisis and the other with cholinergic crisis. All patients, except 2 with neonatal MG, were initially treated with anticholinesterase, but 24% also required steroid therapy. Thymectomy was performed for 12 patients, of whom 5 (42%) showed marked improvement. Thymic histology was normal in 3, showed hyperplasia in 6, non-invasive thymoma in 1 and involution in 2. The most commonly associated disease was Graves' disease which occurred in 7 patients (7%).

Adolescent↗
PubMed1992

Huntington's disease in Chinese: a hypothesis of its origin.

The period prevalence (1984-91) of Huntington's disease (HD) in Hong Kong Chinese was 3.7 per million population. HD patients in Mainland China and Hong Kong showed similar hereditary pattern, clinical and pathological features as in the West. Chinese HD patients were male predominant with a younger age of onset and death. Their ancestral origin could be traced mostly to the coastal provinces of China. It is proposed that Chinese HD patients may have a European origin and share the same gene pool as their white counterparts.

China↗
PubMed1992

Treatment of acute cerebral hemorrhage with intravenous glycerol. A double-blind, placebo-controlled, randomized trial.

BACKGROUND AND PURPOSE: Hitherto, treatment of acute cerebral hemorrhage with intravenous glycerol has not been evaluated in rigorous clinical studies with sufficient patient numbers. METHODS: We undertook a double-blind, stratified and randomized, placebo-controlled clinical trial. Only patients with a first stroke admitted to the hospital within 24 hours after onset of symptoms were recruited, provided computed tomography confirmed hemorrhage and informed consent was obtained. After stratification into alert, semicoma, and coma subgroups using the Glasgow Coma Scale, 107 patients received active treatment (500 ml of 10% glycerol in saline by intravenous infusion over 4 hours on 6 consecutive days) and 109 were given corresponding saline treatment. Using a variety of objective scoring systems, patients were followed up for up to 6 months. RESULTS: At follow-up, all measures of outcome in the treated and control groups were very similar. At 6 months, respective mortality rates were 37 of 107 and 33 of 109. Corresponding mean +/- SD improvements in Scandinavian Stroke Study Group scores were 8.35 +/- 16.9 versus 11.55 +/- 15.6 (long-term) and 0.64 +/- 7.3 versus 2.40 +/- 6.9 (prognostic), and improvements in the Barthel Index ratings were 10.72 +/- 24.7 versus 13.95 +/- 23.3, respectively. Glasgow Coma Scale score improvements in the survivors were 0.81 +/- 1.5 and 1.16 +/- 1.7 in the treated and control groups, respectively. Hemolysis (generally subclinical) was the only adverse effect of glycerol noted. CONCLUSIONS: In the absence of any clinically or statistically significant difference in outcome between the treated and control groups, this trial provides no justification for glycerol therapy following acute cerebral hemorrhage.

Acute Disease↗
PubMed1992

Postinfectious myelitis, encephalitis and encephalomyelitis.

Six cases of post-infectious encephalomyelitis are described. A preceding non-specific viral-like illness occurred 4 to 20 days before the onset of the neurological deficits. The clinical syndromes included transverse myelitis, focal encephalitis and encephalomyelitis (each in one case) and diffuse encephalitis in 3. Magnetic resonance imaging appeared to be the investigation of choice. High dose corticosteroids were given to 4 patients who recovered partially or fully. The patient with focal encephalitis had a spontaneous and complete recovery. The remaining patient with diffuse encephalitis died 3 days after the onset; autopsy showed prominent lymphocytic perivascular cuffing in the white matter and lymphocytic infiltration of the meninges.

Adrenal Cortex Hormones↗
PubMed1992

Effects of thyroidectomy on the hematocrit and blood viscosity in ovariectomized rats.

The hematocrit and blood viscosity were measured in ovariectomized (Ovx) rats following thyroidectomy or sham operation. Rats were thyroidectomized (Tx) or sham Tx immediately after ovariectomy. Three months later, Ovx, Ovx+Tx, and intact rats at proestrus stage were bled. Blood was collected by heart puncture in rats under ether anesthesia and heparinized. One month after the first bleeding, Ovx and Ovx+Tx rats were bled once again. the viscosity of whole blood and plasma was measured at various shear rates at 37 degrees C by means of a Mooney-Ewart viscometer. The hematocrit was determined by a microhematocrit centrifuge. The plasma osmolality was measured by a computerized micro-osmometer. Concentrations of plasma sodium and potassium were measured by a flame photometer. The concentration of plasma thyroid stimulating hormone (TSH) was measured by a radioimmunoassay. In Ovx+Tx rats, the plasma TSH concentration was higher, but the hematocrit and blood viscosity were lower than those in Ovx and proestrus rats. The levels of plasma sodium, osmolality and viscosity were not altered by ovariectomy and thyroidectomy. These results suggest that the lower blood viscosity in thyroidectomized rats is due to a reduction of hematocrit.

Animals↗
PubMed1991

Relative quantification of collagen mRNA in fibroblasts by a radioactive polymerase chain reaction technique.

A radioactive polymerase chain reaction (PCR) method has been developed for the relative quantification of the human alpha-2 chain of type I collagen [hu alpha-2(I)] in cells. cDNAs generated by reverse transcription from the total pool of cytoplasmic RNA serve as a template for polymerase chain reaction amplification of a hu alpha-2(I) cDNA primed by two sequence-specific synthetic oligonucleotides. The distinctive 390 bp hu alpha-2(I) cDNA and two Aval fragments of 220 and 170 bp are identified by agarose gel electrophoresis. alpha-32P-dCTP of defined specific activity is included in the PCR reaction and the 390 bp cDNA is excised from the electrophoresis gel to permit direct radioactive quantification of hu alpha-2(I) mRNA. The amount of hu alpha-2(I) mRNA expressed in as few as 111 fibroblasts was determined reliably. In contrast, the hu alpha-2(I) mRNA from at least 5 x 10(5) fibroblasts was required for detection by Northern blot analysis developed with the same cDNA probe radiolabelled with alpha-32P-dCTP by random priming. Human bronchoalveolar lavage (BAL) fluids of six patients with fibrosing lung diseases stimulated the level of expression of hu alpha-2(I) mRNA in cultured human fibroblasts as determined by this technique. The radioactive PCR method thus quantifies hu alpha-2(I) mRNA in fibroblasts with sufficient sensitivity to study fibroblast activation in vitro and detect fibroblast stimuli in human clinical samples.

Autoradiography↗
PubMed1991

Cerebral haemorrhage in anticoagulated patients with non-septic mechanical valvular prosthesis.

Cerebral haemorrhage in anticoagulated patients with mechanical valvular prosthesis poses an uncommon but difficult management problem. Four such patients are presented: one patient had delayed haemorrhagic transformation of a preexisting cerebral infarct, one probably had de novo haemorrhage complicating hypertension and in two patients cerebral haemorrhage was associated with excessive anticoagulation. Conservative management including the use of fresh frozen plasma, delayed heparinisation and warfarinisation was used. Both patients with anticoagulant overdose died as a result of extensive haemorrhage despite the drainage of cerebellar haematoma in one patient. The remaining two patients survived with minimal neurological deficits. Diagnosis of the underlying cause of cerebral haemorrhage, and the timing of heparinisation and anticoagulation are discussed.

Adult↗
PubMed1991

High prevalence of undiagnosed diabetes among Chinese patients with ischaemic stroke.

We reviewed the prevalence of diabetes mellitus, hypertension and cigarette smoking in 176 Chinese patients with acute stroke, classified, on computed tomographic findings, as intracerebral haemorrhage or cerebral infarction. In all patients with no known history of diabetes, a 75 g OGTT was done 3-6 months after ictus and interpreted using WHO criteria. The overall prevalence of diabetes and impaired glucose tolerance (IGT) was 33.5% and 21.0%, respectively, with a higher prevalence being found in patients with cerebral infarction (P less than 0.05). Forty percent of those with diabetes were previously undiagnosed - all but 2 had ischaemic stroke. Compared to reported findings in the general population, an increased prevalence of hypertension, and possibly also cigarette smoking was found in patients with both stroke categories. On the other hand, significant hypercholesterolaemia was not found in patients of either category. In view of the high prevalence of undiagnosed diabetes among these stroke patients and the increased morbidity and mortality associated with diabetes mellitus, screening for diabetes is recommended especially in those with ischaemic stroke. If a fasting plasma glucose of greater than or equal to 6 mmol/l was used for the initial screening of undiagnosed diabetes in this group of patients, the sensitivity and specificity values would have been 78% and 94%, respectively. Whether this cut-off value can be cost-effectively employed for mass screening remains to be confirmed by studies involving larger numbers of stroke patients.

Blood Glucose↗
PubMed1991

A multimodal neurophysiological assessment in terminal renal failure.

A prospective multimodal neurophysiological study was conducted on 36 patients with end-stage renal failure, 16 of whom subsequently underwent renal transplantation (TR). Nerve conduction study and somatosensory evoked potentials revealed that peripheral conduction deficit, often subclinical, was the commonest abnormality, and TR resulted in substantial improvement. Visual evoked potentials demonstrated subclinical impairment, which did not improve after TR. The brainstem auditory evoked potentials were essentially normal and unaffected by TR.

Brain Stem↗
PubMed1991

Neurological manifestations of systemic lupus erythematosus: a prospective study.

A prospective study of the neurological manifestations in all patients with systemic lupus erythematous (SLE) was conducted between February 1985 to January 1989. Excluding herpes zoster infection of peripheral or cranial nerves, post-herpetic neuralgia and migraine, 36 neurological episodes occurred in 33 patients. The presenting symptoms were mental confusion (10), psychosis (five), seizures (six), focal neurological deficit (three), coma (two), headache (five), blurring of vision (three), neuropathy (one) and myelopathy (one). Of these manifestations, only eight episodes were due to primary involvement by SLE: psychosis (two), seizure (two), multiple cerebral infarcts (one), papillitis (one), neuropathy (one) and myelopathy (one). Infection was the most common secondary cause of neurological episodes: all 10 episodes of mental confusion (fungal seven, pyogenic two, tuberculous one, nocardial one); two of six seizures (tuberculous one, pyogenic one); all five headaches (tuberculous meningitis three, cryptococcal meningitis two). The other secondary causes included steroid psychosis (two), hypertensive encephalopathy with seizure (one) and hypertensive retinopathy (one). Three of five cases of focal neurological deficit were due to macrovascular disease rather than to vasculitic infarction. We concluded that cerebral psychosis was a relatively rare presentation in our patients with SLE. In patients who presented with a neurological problem, especially mental confusion, efforts should be made to ascertain the underlying cause, especially if this may be an infection.

Adult↗
PubMed1991

Pattern of memory deficits in a controlled psychometric study of thalamic haemorrhage.

Twelve patients with unilateral thalamic haemorrhages were assessed psychometrically. The results were compared with control subjects matched for sex, age and years of education. The pattern of deficits and preserved abilities cannot be explained in terms of semantic/episodic distinction, but could be interpreted as manifestations of disconnection between the frontal and temporal systems.

Aged↗