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Biomedical subjects

R T Cheung

Publications and source records attributed to R T Cheung.

At least 19 recordsLinked to original sources
PubMed2001

Hong Kong patients' knowledge of stroke does not influence time-to-hospital presentation.

A prospective interview of consecutive patients admitted with acute stroke was conducted over an 8-week period to study the influence of patients' knowledge of stroke on time to presentation in Hong Kong. Early arrival was defined as within 6h of symptom onset. The patients' general knowledge of stroke was fair, and early arrival was seen in 40 (56.3%) of 71 patients. Early presentation was associated with male sex (P= 0.028) and a lower initial Glasgow coma scale score (P= 0.072), but not with age, a better general knowledge of stroke, a previous history of stroke or transient ischaemic attack, Rankin score upon discharge, and level of education. On the other hand, late presentation was associated with a belief in permanent disability (P= 0.056). Thus, improving the general knowledge of stroke among Hong Kong people may not reduce delay in hospital presentation of stroke patients.

Acute Disease↗
PubMed2001

Intracarotid abciximab injection to abort impending ischemic stroke during carotid angioplasty.

BACKGROUND: Abciximab, a platelet glycoprotein IIb/IIIa receptor antagonist, prevents ischemic complications during percutaneous transluminal coronary angioplasty and was recently shown to open occluded vessels in patients with acute myocardial infarction when used alone or in combination with other thrombolytic agents. In an animal model of arterial thrombosis, abciximab was found to be safe and effective for the prevention of carotid artery thrombosis. However, the safety and efficacy of abciximab in the treatment of acute ischemic cerebrovascular events is unknown at present. CASE DESCRIPTION: We describe 3 patients who experienced ischemic cerebrovascular events with symptoms involving the middle cerebral artery territory while undergoing percutaneous angioplasty and stenting to their internal carotid arteries. Abciximab was administered to each patient within 10 min of symptom onset as a bolus (0.25 mg/kg) into the ipsilateral common carotid artery followed by continuous intravenous infusion (9 microg/min) for 12 h. All patients' symptoms resolved completely (by 25 min, 40 min and 5 h, respectively) with no further neurological complications. CONCLUSIONS: Our preliminary observation suggests that abciximab may improve neurological outcome following middle cerebral artery ischemic events associated with carotid angioplasty and stenting. Large prospective studies are warranted to establish the safety and efficacy of abciximab in acute ischemic stroke, either as a primary treatment modality or an adjunct to carotid angioplasty and stenting.

Abciximab↗
PubMed2001

Circadian variation of stroke onset in Hong Kong Chinese: a hospital-based study.

Circadian variation of onset of transient ischaemic attack (TIA) or stroke during four 6-hourly periods starting from midnight was studied in Hong Kong Chinese patients admitted to a regional hospital between October 1996 and July 1999. The onset was classifiable into one of the 6-hourly periods in 832 of 905 patients; patients with unclassifiable onset were more likely to have lacunar infarct and less likely to have intracerebral haemorrhage (ICH). There was a significant circadian variation of onset in all strokes and TIA, TIA alone, ischaemic stroke (IS), ICH and different IS subtypes. The risk of onset was greatest between 6 a.m. and noon for IS or TIA, but between noon and 6 p.m. for ICH. There was no difference in the circadian variation between patients with and without prior TIA or stroke. This hospital-based study revealed a significant circadian variation of onset in different types and subtypes of stroke.

Adult↗
PubMed2001

Cerebrovascular disease--advances in management.

Recent advances in the diagnosis and treatment of stroke have justified its management as a medical emergency. This article summarises the current recommendations for the initial management of major types of stroke with emphasis on acute therapy for ischaemic stroke. Recommendations are based on results of well-designed clinical trials. An acute stroke care team and an acute stroke unit should be established in all regional hospitals. Diagnosis of stroke must be accurate. General management aims for prevention and treatment of neurological and systemic complications, whereas specific management varies according to the stroke type and the underlying pathogenic mechanisms. For selected patients with ischaemic stroke, intravenous recombinant tissue plasminogen activator or a modified viper venom within 3 hours of onset, or intra-arterial pro-urokinase within 6 hours may improve functional outcomes. Neurosurgical treatment is indicated for some patients with ischaemic or haemorrhagic strokes. Prevention of recurrence and rehabilitation are the core components of subsequent management.

Anticoagulants↗
PubMed2000

The insula and cerebrogenic sudden death.

Sudden death is an "electrical accident" caused by fatal cardiac arrhythmias. While brain-heart control has physiological advantages, cerebrogenic sudden death and nonfatal cardiovascular disturbances can complicate stroke of all types, seizures and epilepsy, head injury, other neurological conditions, neurosurgical procedures, and intense emotional states. Cerebrogenic cardiovascular and autonomic disturbances include electrocardiographic changes, elevation of cardiac enzymes, cardiac arrhythmias, disturbances of blood pressure regulation, and cerebrogenic pulmonary edema. Evidence from experimental studies and clinical observations indicates a crucial role of the insula in cerebrogenic cardiovascular disturbances and sudden death. Future studies should focus on identification of at-risk patients, confirmation of a vulnerable period of cerebrogenic sudden death in those with different neurological conditions and intense emotional states, and clarification of the neurochemical mediators.

Animals↗
PubMed2000

Neuropeptide Y-Y1 receptor antisense oligodeoxynucleotide increases the infarct volume after middle cerebral artery occlusion in rats.

An antisense oligodeoxynucleotide selective for the rat neuropeptide Y1 receptor gene was given into the left lateral ventricle in the experimental group of rats, whereas a missense oligodeoxynucleotide or saline was given in the control groups. Some rats were decapitated at 1-2h after the last injection of the oligodeoxynucleotides to examine their effects on the Y1 receptor density in the insular cortex. When compared to the Y1 and Y2 binding density of the untreated rats, the antisense-treated rats had reduced Y1 binding in the insular cortex but the Y2 binding was unaffected; treatment with missense oligodeoxynucleotide had no effect. Other rats underwent a right-sided middle cerebral artery occlusion at 1-2h after the last injection of the oligodeoxynucleotides or saline to examine the effect on the infarction volume at three days following stroke. The antisense treatment resulted in a doubling of the mean infarction volume when compared to the missense or saline treatment.Thus, reducing the Y1 receptor density prior to middle cerebral artery occlusion is harmful. Neuropeptide Y may mediate neuroprotection against focal ischemia via the cortical Y1 receptor, since the immunoreactivity for neuropeptide Y has been shown to increase within the peri-infarct cortex after middle cerebral artery occlusion.

Animals↗
PubMed2000

Prevalence of migraine, tension-type headache, and other headaches in Hong Kong.

OBJECTIVE: To assess the prevalence of migraine and other headaches in Hong Kong in 1998. BACKGROUND: A community-based prevalence survey of headache was carried out from July 1992 to March 1993, and the prevalence rates were 1% for migraine, 2% for tension-type headache, and 1% for other headaches. A similar survey was carried out in May and June 1998 to interview individuals aged 15 years or older. Recurrent headache was defined as having two or more headaches unrelated either to influenza or a common cold within the past 12 months. METHODS: Respondents with recurrent headache were offered a personal interview for clinical validation. Of 3156 randomly selected individuals, 1436 responded. RESULTS: Headache was due to influenza or a common cold in 270 (18.8%) respondents; recurrent headache affected 533 (37.1%) respondents. The overall prevalence rates were 4.7% for migraine, 26.9% for tension-type headache, and 5.5% for other headaches. Clinical validation was available for 72 respondents. After adjustment for possible misclassification, the estimated prevalence rates became 12.5% for migraine, 18.7% for tension-type headache, and 6.0% for other headaches. There was a female preponderance for all types of headache with a peak in the 25- to 34-year-age group for tension-type headache. CONCLUSIONS: All types of headache were more common in the 1998 study, and the prevalence rates were closer to those of Western communities.

Adolescent↗
PubMed2000

The Holmes-Adie plus syndrome.

A clinical syndrome of tonic pupil associated with tendon areflexia was first described by Holmes and Adie; autonomic neuropathy and peripheral neuropathy can be associated. The postulated mechanism of areflexia in Holmes-Adie syndrome is a synaptic disorder of the spinal reflex pathways. We report a case of a Holmes-Adie syndrome variant with hitherto unreported cranial neuropathy. A 41 year old woman developed insidious onset of sensory symptoms related to her left trigeminal and chorda tympani nerves over a few months. Physical examination showed generalised tendon areflexia and a left sided Adie's pupil. Imaging did not reveal any structural abnormality. Electrophysiological studies demonstrated an absent blink reflex on stimulating the left supraorbital and infraorbital nerves. These findings were suggestive of a dysfunction affecting the brain stem reflex arc. The pathophysiological process of Holmes-Adie syndrome may be more widespread than previously thought.

Adie Syndrome↗