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Biomedical subjects

S L Ho

Publications and source records attributed to S L Ho.

At least 19 recordsLinked to original sources
PubMed2003

Clinical relevance of hydrocephalus as a presenting feature of tuberculous meningitis.

BACKGROUND: Hydrocephalus is a common complication of tuberculous meningitis (TBM). AIM: To study the incidence, associated clinical features, and impact on outcome of hydrocephalus at presentation in TBM. DESIGN: Observational study. SETTING: Regional hospital serving 500,000 people. METHODS: Adult patients with TBM were studied over 57 months. Those with hydrocephalus on initial CT scan were assessed by neurosurgeons. Clinical, neuroradiological, and biochemical features of patients with hydrocephalus upon presentation were compared to those without initial hydrocephalus. RESULTS: Of 31 TBM patients during the study period, nine (29.0%) had hydrocephalus at presentation, and eight of them (25.8% of all) underwent urgent neurosurgical intervention. Of the 22 patients without initial hydrocephalus, hydrocephalus developed after commencement of chemotherapy in one patient only. Hydrocephalus at presentation was associated with a longer duration of presenting symptoms (p = 0.01), ataxia (p = 0.001), later stages of TBM (p = 0.045), a longer delay before commencement of anti-tuberculous chemotherapy (p = 0.001), stroke (p = 0.012), and a poor outcome at 1 year (p = 0.001). DISCUSSION: Hydrocephalus upon presentation is common in our TBM patients. This may be a poor prognostic marker associated with severe TBM and a higher risk of stroke.

Adult↗
PubMed2003

A prevalence study of epilepsy in Hong Kong.

OBJECTIVES: To examine epidemiological data on epilepsy for the Hong Kong west region. DESIGN. Descriptive study. SETTING: Epilepsy clinic, university teaching hospital, Hong Kong. PATIENTS AND METHODS: The epilepsy clinic of Queen Mary Hospital manages the majority of adult patients (aged 15 years or older) with chronic seizure disorders resident in the Hong Kong west area with an adult population of 475,900. All patients underwent electroencephalography examination and each subject was independently assessed by two epileptologists for diagnosis and classified according to the International League Against Epilepsy recommendations. RESULTS: Seven hundred and thirty-six patients (female, 42.9%; male, 57.1%; mean age, 40.8 years; standard deviation, 13.6 years) with epilepsy were enrolled in the study. The prevalence rate of active epilepsy in the population 15 years or older was estimated at 1.54 per 1000 on 1 January 2002. Two hundred and eighty-five (38.7%) patients had idiopathic epilepsy syndromes, 100 (13.6%) had cryptogenic epilepsy, and 285 (38.7%) had a remote symptomatic aetiology. Seizure type was partial in 408 (55.4%) patients and generalised in 285 (38.7%). Thirty-one (4.2%) patients had a positive family history. Idiopathic generalised epilepsy syndromes described as common in the literature, such as juvenile myoclonic epilepsy and childhood absence epilepsy, were infrequently seen at 0.68% and 0.95% of cases, respectively. CONCLUSIONS: This study provides baseline data for epilepsy service development and research in Hong Kong. The prevalence rate of active epilepsy in this Chinese, adult population was low compared with that reported in other developed countries. Further population-based epidemiological research is indicated to confirm the prevalence of seizure disorders in this locality.

Adolescent↗
PubMed2002

Lateral temporal hyperperfusion in postictal psychosis assessed by 99mTc-HMPAO SPECT.

Postictal psychosis is a rare complication of epileptic seizure characterized by reversible psychotic symptoms after flurries of seizure attack. It has been attributed to a phenomenon similar to Todd's paralysis without definitive proof. We studied regional cerebral blood flow (rCBF) of six patients with postictal psychosis by (99m)Tc-HMPAO SPECT scan. Baseline rCBF was compared with the rCBF during postictal psychosis. An asymmetry index (ASI) was calculated as 200 x [(ipsilateral ROI count density - contralateral ROI count density)/(ipsilateral ROI count density + contralateral ROI count density)] %. Significant differences could be found between ASIs during postictal psychosis and interictal state SPECT scan over the lateral temporal neocortex region (P = 0.017). Although hyperperfusion abnormality in SPECT can be found in Todd's paralysis, such findings are more commonly found in cerebral hyperactivity conditions. Taking into account the clinical characteristics of postictal psychosis, namely a preceding lucid interval and crescendo-decrescendo clinical course, these may be an alternative psychopathogenic mechanism for the development of postictal psychosis.

Adolescent↗
PubMed2002

Two large British kindreds with familial Parkinson's disease: a clinico-pathological and genetic study.

We present the findings of a study of two large unrelated kindreds with autosomal dominant Parkinson's disease. The affected members were assessed clinically and with [(18)F]6-fluorodopa-PET and were indistinguishable from patients with the sporadic form of Parkinson's disease. In one kindred, an affected member was examined subsequently at autopsy and Lewy bodies were present in a distribution typical of sporadic Parkinson's disease. These kindreds are distinct from other Parkinsonian kindreds with identified genetic loci (PARK1-4) and provide further evidence for genetic heterogeneity in familial Parkinson's disease.

Adult↗
PubMed2001

Induction of unspliced c-fos messenger RNA in rodent brain by kainic acid and lipopolysaccharide.

The c-fos transcriptional factor forms an activator protein-1 (AP-1) complex with proteins from the Jun family, which plays an important role in the central nervous system. The responses of AP-1 transcriptional factors induced by kainic acid (KA) treatment have been well studied, although the transcriptional regulation of these KA-induced factors has not been clearly characterized. To investigate the role of different stimuli in controlling of the splicing of c-fos mRNA, we performed reverse transcriptional polymerase chain reaction. The results showed that spliced and unspliced c-fos is present in rat brain following KA treatment and in lipopolysaccharide (LPS)-treated primary mouse cortical brain cell cultures. Furthermore, tyrosine kinase and protein phosphatase inhibitors alter the preponderance of c-fos transcripts following LPS treatment.

Animals↗
PubMed2001

Oral stereognosis in stroke and Parkinson's disease: a comparison of partially dentate and edentulous individuals.

Oral stereognosis was measured in partially dentate and edentulous patients with stroke, Parkinson's disease, and an age and gender-matched control group. Stereognostic tests involving conventional free intra-oral manipulation of test objects were undertaken in the partially dentate and edentulous with and without complete dentures. Comparisons were made using the unpaired t-test and ANOVA. Edentulous stroke patients without dentures had significantly greater error scores and fewer correct identifications compared with partially dentate stroke patients. Stereognostic measures were similar in the partially dentate and edentulous with dentures, within experimental groups. In the partially dentate, there were no differences in stereognostic measures between the three groups. Stereognostic measures were poorer in edentulous stroke patients with and without dentures compared with the edentulous control group. Partially dentate stroke patients are less likely to have impaired oral stereognosis than edentulous stroke patients.

Aged↗
PubMed2001

Balloon dacryocystoplasty study in the management of adult epiphora.

PURPOSE: To determine the efficacy of dacryocystoplasty with balloon dilation in the treatment of acquired obstruction of the nasolacrimal system in adults. METHODS: Balloon dacryocystoplasty was performed in 52 eyes of 42 patients under general anaesthetic. A Teflon-coated guidewire was introduced through the canaliculus and manipulated through the nasolacrimal system and out of the nasal aperture. A 4 mm wide 3 cm coronary angioplasty balloon catheter was threaded over the guidewire in a retrograde fashion and dilated at the site of obstruction. RESULTS: There was complete obstruction in 30% of cases and partial obstruction in 70%. The most common site of obstruction was the nasolacrimal duct. The procedure was technically successful in 94% of cases. The overall re-obstruction rate was 29% within 1 year of the procedure. There was an anatomical failure rate of 17% for partial obstruction and 69% for complete obstruction within 1 year. CONCLUSIONS: Balloon dacryocystoplasty has a high recurrence rate. There may be a limited role for this procedure in partial obstructions. Further refinements of the procedure are necessary before it can be offered as a comparable alternative to a standard surgical dacryocystorhinostomy.

Adolescent↗
PubMed2001

Evaluation of four breath-enhanced nebulizers for home use.

The objective of this study was to evaluate relative efficiency in vitro of four reusable breath-enhanced nebulizers (Pari LC Star, Medic-Aid Ventstream, Devilbiss PermaNeb, Salter Ultramist), and to integrate the in vitro performance data of the nebulizers with the respiratory patterns of four cystic fibrosis (CF) patients to compare efficiency in vivo of each device for each individual patient. Six nebulizers of each type were used to nebulize a solution of 2.5 mg (0.5 mL) albuterol with 3.5 mL of 0.9% saline. Total albuterol output and the rate of albuterol output of each device were measured until end-nebulization and for 4 min, respectively, using entrained flows from 0 to 20 L/min through the inspiratory valve of the device. Particle size distributions and the respirable fraction (RF) were evaluated by laser diffraction technique. Regression analysis of the change in rate of output and change in RF values with inspiratory flows was done to characterize each nebulizer's performance over the complete range of interest. Actual breath tracings of four CF patients were integrated with the equations specific to the in vitro performance of each nebulizer and in vivo nebulizer efficiency was calculated. The change in efficiency in vitro from 0 to 20 L/min flow, respectively, was highest for the Star (44-57%) and lowest for the Ultramist (13-15%). The mean predicted efficiency in vivo for the Star was threefold that of the Ultramist. Although all four nebulizers are breath-enhanced in design, clearly there are measurable differences in the performance and efficiency of each type. The Pari LC Star nebulizer has proven to be the nebulizer of choice among the devices tested.

Aerosols↗
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

Nebulizer choice for inhaled colistin treatment in cystic fibrosis.

STUDY OBJECTIVES: To develop practical ways of nebulizing colistin by determining the rate of drug output, total drug output, and particle-size distribution of two commercially available jet nebulizers, the disposable Hudson 1730 Updraft II (Hudson Respiratory Care; Temecula, CA) and the reusable Pari LC Star breath-enhanced nebulizer (Pari Respiratory Equipment; Midlothian, VA). METHODS: The nebulizers contained colistin, 75 mg, in 4 mL of isotonic solution. Particle-size distribution was measured by helium-neon laser diffraction, allowing calculation of the respirable fraction (RF), the mass of aerosol comprised of droplets < 5 microm. RESULTS: The mean (95% confidence interval [CI]) total rate of output of the Updraft II was 2.6 mg/min (2.0, 3.1; n = 4) with 1.3 mg/min (1.0, 1.5) mg/min within the RF. The rate of output of the LC Star increased in a quadratic relationship to the inspiratory flow, delivering 1.8 mg/min (0.7, 2.0; n = 4) with 1.4 mg/min (1.3, 1.6) within the RF, and 6.2 mg/min (5.6, 6.8) with 5.3 mg/min (4.8, 5.7) within the RF, at 0 L/min and 20 L/min inspiratory flows, respectively. Efficiency, as the rate of expected pulmonary deposition divided by rate of total output, was then calculated. The LC Star estimated 56% (51, 61) efficiency, with pulmonary delivery of 29% (26, 32) of the charge of the nebulizer, compared to the Updraft II at 22% (22, 23) efficiency and expected pulmonary deposition of 10% (10, 10) of the dose. CONCLUSIONS: Colistin can be successfully nebulized with both nebulizers tested. This study provides an estimate of in vivo efficiency and expected pulmonary deposition that may be used in future trials.

Adolescent↗
PubMed2001

Effect of size and disease on estimated deposition of drugs administered using jet nebulization in children with cystic fibrosis.

STUDY OBJECTIVES: To develop a model that quantified the nebulizer output that was inhaled by subjects with cystic fibrosis (CF) in order to predict the amount of drug likely to enter the upper airway contained in particles small enough to be deposited in the lower respiratory tract of individual patients. DESIGN: Forty-three patients (age, 6 to 18 years) with CF, with FEV(1) of 26 to 124% of predicted, breathed through a nebulizer circuit with a pneumotachograph in place at the distal end. Algorithms were developed from the measured flows through the pneumotachograph, allowing partitioning of inspiration into undiluted aerosol and fresh gas. In order to validate the algorithms, argon was added to the nebulizing gas flow and then its concentration was analyzed at the mouth by mass spectrometry. RESULTS: Predictions of the concentration of argon at the mouth were concordant with that measured by mass spectrometry, thus validating the model. Combining data from the model with in vitro nebulizer performance data, predictions for estimates for lung deposition for individuals were possible. Total estimate was independent of patient size or FEV(1). The respiratory duty cycle was 0.44 +/- 0.05 (mean +/- SD) and correlated (r = 0.91, p < 0.001) with estimated deposition and minute ventilation (r = 0.60, p < 0.01). However, when expressed in milligrams per kilogram of body weight, the estimated deposition in smaller children was fourfold higher than in larger children. CONCLUSIONS: If the effect of patient size and pattern of breathing on estimated drug deposition are not considered when prescribing drugs given by nebulization, the result may be overdosing younger children, underdosing older children, or both.

Administration, Inhalation↗
PubMed2001

The impact of molecular biology on clinical neurology.

Advances in molecular biology have increased our understanding of both inherited and sporadic forms of neurological disease. In this review, the impact of these advances is discussed in relation to specific neurological conditions. These include the hereditary neuropathies and ataxias, Huntington's disease, and the muscular dystrophies, as well as Alzheimer's disease, Parkinson's disease, and motor neuron disease. Genetic channelopathies, such as familial hemiplegic migraine, are also described. Although knowledge in this area overall is still relatively scant, current advances in molecular biology have helped in the reclassification of some neurological disorders, thereby providing a further step towards the development of rational therapies to treat these conditions.

Alzheimer Disease↗
PubMed2001

The aetiology of idiopathic Parkinson's disease.

Agents potentially involved in the aetiology of idiopathic Parkinson's disease are discussed. These include factors regulating dopaminergic neurogenesis (Nurr 1, Ptx-3, and Lmx1b) and related proteins, together with genes involved in familial Parkinson's disease (alpha synuclein, parkin, and ubiquitin carboxy terminal hydroxylase L1), and endogenous and environmental agents.

Animals↗
PubMed2000

Estrogen improves motor disability in parkinsonian postmenopausal women with motor fluctuations.

OBJECTIVE: To test the efficacy, tolerance, and safety of low-dose oral estrogen in postmenopausal women with PD associated with motor fluctuations. BACKGROUND: Motor fluctuations in PD may be predictable or unpredictable, and eventually affect most patients after long-term levodopa therapy. Although estrogen can modulate nigrostriatal dopamine levels, its effects on PD are unclear. METHODS: Patients were randomized to receive conjugated estrogen (oral Premarin 0.625 mg daily; n = 20) or placebo (n = 20) in a double-blind, parallel-group, prospective study over 8 weeks. Existing antiparkinsonian drug regimes were kept unchanged. Changes in "on" and "off" periods using patient diaries, Unified Parkinson's Disease Rating Scale (UPDRS) score, timed tapping score, and Hamilton Depression Scale score were determined by one rater. Subgroup analyses were also performed on patients with only predictable motor fluctuations. RESULTS: Both treatment groups were similar in age, duration of disease and menopause, antiparkinsonian medication, and compliance with test medication and diary assessments. "On" and "off" times, and motor score (UPDRS subscale III) improved with estrogen, using the Mann-Whitney U test (p < 0.05 after Bonferroni adjustment). Mean "on" time improved by 7% (9 hours/week of awake time) in estrogen-treated patients versus a deterioration of 0.5% (1.4 hours) in placebo-treated patients (95% confidence interval, [CI] of mean difference, 5.73 to 14.9). Mean "off" time improved by 4% (4.4 hours/week of awake time) in estrogen-treated patients versus no change in placebo-treated patients (95% CI, 1.54 to 7.16). Mean subscale III score improved by 3.5 points in estrogen-treated patients versus 0.4 in placebo-treated patients (95% CI, 1.02 to 5.18). No other significant changes were observed (p > 0.05). Subgroup analyses in patients with only predictable motor fluctuations showed similar results, except improvement in mean subscale III score was marginally not significant (p = 0.07; 95% CI, 1.06 to 6.24). Five patients on estrogen had facial flushing, three had lower abdominal discomfort, and two had mild withdrawal vaginal bleeding. The adverse events were mild and resolved without sequelae. CONCLUSION: Low-dose estrogen is a safe and effective adjunct therapy to existing antiparkinsonian treatment in reducing motor disability in postmenopausal women with PD associated with motor fluctuations.

Activities of Daily Living↗