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Benjamin K C Ong

Publications and source records attributed to Benjamin K C Ong.

17 recordsLinked to original sources
PubMed2006

Where has all the botox gone? (how) will we ever learn... using monoclonal antibodies to track botulinum toxin.

Botulinum toxin (BTX) is an important therapeutic tool in the treatment of overactive skeletal and smooth muscles, as well as hypersecretory and painful disorders. Despite advances in our understanding of how BTX works, much remains to be elucidated, such as how BTX ameliorates pain, how it produces weakness remote from the site of injection and the fate of the heavy and light chain components of the BTX molecule following endocytosis into the presynaptic membrane. BTX, conjugated to radionuclides, allows investigators to track the molecule both in vitro and in vivo. However, altering the BTX molecule may cause structural changes or pharmacokinetic and pharmacodynamic alterations, and disrupt its normal action. We propose instead to bind the biomarkers (appropriate dyes, radionuclides or MRI contrast agents) to monoclonal antibodies directed against either heavy or light chain components of BTX, thus allowing administration of native (i.e. unaltered) BTX.

Animals↗
PubMed2006

Topical botulinum toxin to treat hyperhidrosis? No sweat!

Palmar, plantar and axillary hyperhidrosis, though benign, may be burdensome and occupationally restrictive, even hazardous. Treatment modalities range from topical antiperspirants, iontophoresis, systemic medications such as anticholinergics and benzodiazepines and injections of botulinum toxin, to thoracic sympathectomy. Intradermal injections of botulinum toxin (BTX), though effective, are painful especially when multiple injections are required. Iontophoretic administration of BTX has been described, the BTX entering the eccrine sweat glands via the sweat pores and through the sweat ducts. We postulate that BTX can be administered topically, either unassisted or assisted by application of an electrical gradient, low-frequency ultrasound or excipients such as dimethylsulfoxide. We examine the rationale and feasibility for such a treatment modality and route of administration.

Administration, Topical↗
PubMed2006

A unique case of reversible hyperglycemic Holmes' tremor.

Various movement disorders are known manifestations of nonketotic hyperglycemia (NKH). Hyperglycemic tremors are rare, with only two cases resembling flapping tremors reported in literature. We present a unique case of reversible hyperglycemic Holmes' tremor associated with NKH and postulate the underlying pathophysiology of this condition.

Aged↗
PubMed2006

Botulinum toxin: a novel therapeutic option for bronchial asthma?

Two components are essential for the development of an attack of bronchial asthma: inflammation and bronchoconstriction, the latter being mediated by smooth muscle contraction. Despite the efficacy of chronic therapy, many asthmatics relapse. Measures to inhibit contraction of the airway smooth muscle, such as vagotomy and thermoablation, may decrease the bronchoconstrictor component of the asthma attack and help to decrease morbidity and mortality from the disease. Botulinum toxin acts to weaken skeletal and smooth muscle by preventing the docking of the acetylcholine vesicle on the inner surface of the presynaptic membrane, thus causing chemical denervation and paresis of skeletal or smooth muscle. We explore the possibility that administration of botulinum toxin may achieve the same effect in bronchial asthma and examine the evidence to support this hypothesis.

Asthma↗
PubMed2006

Computer-based versus pen-and-paper testing: students' perception.

BACKGROUND: Computer-based testing (CBT) has become increasingly popular as a testing modality in under- and postgraduate medical education. Since 2004, our medical school has utilised CBT to conduct 2 papers for the third- and final-year assessments - Paper 3, with 30 multiple choice questions featuring clinical vignettes, and the modified essay question (MEQ) paper. AIMS: To obtain feedback from final-year students on their preferred mode of testing for Paper 3 and MEQ components of the Medicine track examination, and the reasons underlying their preferences. METHODS: An online survey was carried out on 213 final-year undergraduates, in which they were asked to provide feedback on Paper 3 and MEQ papers. Students were asked if they thought that the CBT format was preferable to the pen-and-paper (PNP) format for Paper 3 and the MEQ, and why. RESULTS: One hundred and fourteen out of 213 (53.5%) students completed the online survey. For Paper 3, 91 (79.8%) felt that CBT was preferable to PNP, 11 (9.6%) preferred the PNP format and 12 (10.5%) were unsure. For the MEQ, 62 (54.4%) preferred CBT over PNP, 30 (26.3%) preferred the PNP format and 22 (19.3%) were unsure. Reasons given to explain preference for CBT over PNP for Paper 3 included independence from seating position, better image quality (as images were shown on personal computer screens instead of projected onto a common screen) and the fact that CBT allowed them to proceed at their own pace. For the MEQ, better image quality, neater answer scripts and better indication of answer length in CBT format were cited as reasons for their preference. CONCLUSIONS: Our survey indicated that whereas the majority of students preferred CBT over PNP for Paper 3, a smaller margin had the same preference for the MEQ.

Clinical Competence↗
PubMed2005

Botulinum toxin-A injections for spastic toe clawing.

Spastic toe clawing describes extension at the metatarsophalangeal joints of the feet, flexion at the proximal interphalangeal joints and flexion at the distal interphalangeal joints that results from upper motor neuron lesions, such as stroke, intracranial hemorrhage, cervical myelopathy and brain tumors. Even though toe clawing is often asymptomatic, it can be painful. Previous studies have described the efficacy of injections of botulinum toxin type-A (BTX-A) to the long flexors of the toes, but this is often unsatisfactory as high dosages (up to 175 units) have been required, and patients often report significant residual toe clawing. We performed an open label, prospective study to assess the efficacy of BTX-A injections, targeting the long and short flexors of the toes, performed with electrical (motor point) stimulation under electromyographic guidance. Outcome measures, which included timed walking over 20m, objective assessment of toe clawing (modified Ashworth scale and a visual analog scale rating) and patient assessment of functional disability, were assessed before injections and at six-weeks' follow-up. Seven patients (five male and two female) of mean age 51 (range 38-70) were recruited. Four had spasticity from underlying intracranial hemorrhage, the remaining three from cerebral infarct, astrocytoma and post-traumatic cervical myelopathy. The total dose of BTX-A injected for toe clawing ranged from 40 to 90 units. Improvements were observed in all outcome measures except timed walking. Injecting BTX-A to the long and short flexors of the toes, with electrical stimulation under electromyographic guidance, is well tolerated and efficacious in the treatment of toe clawing from spasticity, allowing for lower dosages to be used.

Adult↗
PubMed2005

Frequency of provocative factors in epileptic patients admitted for seizures: a prospective study in Singapore.

Intractable epilepsy is commonly believed to be the main cause of uncontrolled seizures and hospitalization in epileptic patients. We study frequency and types of potential provocative factors in epileptic patients admitted with seizures, and suggest methods to decrease seizure occurrence and hospitalization. Over 6 months we prospectively studied all epileptic patients hospitalized for seizures. A structured interview and laboratory investigations were used to determine type and number of potential seizure precipitants. Precipitants thought to be avoidable through actions taken by the patient or physicians were termed potentially preventable provocative factors (PPPF). Patients' awareness and knowledge of seizure precipitants were also assessed. Three quarters of all seizures leading to admission were associated with PPPF, the commonest being non-compliance (71%), sub-therapeutic doses of antiepileptic drugs (26%) and sleep deprivation (9%). Only one patient had intractable epilepsy. Patients' knowledge of seizure precipitants was poor. The majority of hospital admissions for seizures in epileptic patients are associated with potentially preventable causes amenable to education programmes. Patient education involving epilepsy nurse educators may play an important role in decreasing seizure occurrence and possibly unnecessary hospital admissions.

Adult↗
PubMed2005

Relationship of inspiratory flow rate and volume on digit tip skin and ulnar artery vasoconstrictor responses in healthy adults.

Reflex vasoconstrictive responses are commonly used to assess sympathetic nerve function of the extremities. A regularly used reflex trigger is deep and rapid inspiration. However, little is known about the relationship between respiratory effort and the magnitude of the resultant vasoconstrictor response. This study investigates the association of inspiratory flow rate and volume to the level of vasoconstrictor reflexes in the 4th digit tip skin and the ulnar artery in 12 healthy volunteers (age range 21-65, mean 38.1 years). The effects of Peak Inspiratory Flow (PIF) and Forced Inspiratory Vital Capacity (FIVC) on blood flow were measured at three levels of respiratory effort: low (PIF < 1.0 l/min; FIVC < 1.0 l), medium (PIF = 1.0-1.5 l/min; FIVC = 1.0-1.5 l), and high (PIF > 1.5 l/min; FIVC > 1.5 l) at two separate occasions. Ulnar vasoconstrictor responses showed good correlation with all levels of respiratory effort. Skin digit tip responses showed good correlation at medium and high levels but not at low respiratory effort. Repeatability of both tests was good. Correlation of inspiratory flow rate to vasoconstriction was consistently better than with inspiratory volume. Both digit tip and ulnar vasoconstrictor responses were maximal with greatest respiratory effort.

Adult↗
PubMed2005

Computer calculated dose in paediatric prescribing.

BACKGROUND AND OBJECTIVE: Medication errors are an important cause of hospital-based morbidity and mortality. However, only a few medication error studies have been conducted in children. These have mainly quantified errors in the inpatient setting; there is very little data available on paediatric outpatient and emergency department medication errors and none on discharge medication. This deficiency is of concern because medication errors are more common in children and it has been suggested that the risk of an adverse drug event as a consequence of a medication error is higher in children than in adults. OBJECTIVE: The aims of this study were to assess the rate of medication errors in predominantly ambulatory paediatric patients and the effect of computer calculated doses on medication error rates of two commonly prescribed drugs. METHODS: This was a prospective cohort study performed in a paediatric unit in a university teaching hospital between March 2003 and August 2003. The hospital's existing computer clinical decision support system was modified so that doctors could choose the traditional prescription method or the enhanced method of computer calculated dose when prescribing paracetamol (acetaminophen) or promethazine. All prescriptions issued to children (<16 years of age) at the outpatient clinic, emergency department and at discharge from the inpatient service were analysed. A medication error was defined as to have occurred if there was an underdose (below the agreed value), an overdose (above the agreed value), no frequency of administration specified, no dose given or excessive total daily dose. The medication error rates and the factors influencing medication error rates were determined using SPSS version 12. RESULTS: From March to August 2003, 4281 prescriptions were issued. Seven prescriptions (0.16%) were excluded, hence 4274 prescriptions were analysed. Most prescriptions were issued by paediatricians (including neonatologists and paediatric surgeons) and/or junior doctors. The error rate in the children's emergency department was 15.7%, for outpatients was 21.5% and for discharge medication was 23.6%. Most errors were the result of an underdose (64%; 536/833). The computer calculated dose error rate was 12.6% compared with the traditional prescription error rate of 28.2%. Logistical regression analysis showed that computer calculated dose was an important and independent variable influencing the error rate (adjusted relative risk = 0.436, 95% CI 0.336, 0.520, p < 0.001). Other important independent variables were seniority and paediatric training of the person prescribing and the type of drug prescribed. CONCLUSIONS: Medication error, especially underdose, is common in outpatient, emergency department and discharge prescriptions. Computer calculated doses can significantly reduce errors, but other risk factors have to be concurrently addressed to achieve maximum benefit.

Adolescent↗
PubMed2005

MS Across Continents: Challenging our Knowledge of MS in Asia and the Middle East. Report from the 2nd MS Forum Pan-Asian Conference, 19-20 November 2004, Ho Chi Minh City, Vietnam.

Multiple sclerosis in Asia and the Middle East shares many similarities with the disease seen in Caucasian populations, but there are notable and important differences. These need to be characterized and defined to enable correct diagnosis. Classifying and diagnosing MS in Asian and Middle Eastern populations were themes of the 2nd MS Forum Pan-Asian conference. Participants also discussed other 'hot topics', such as health economics and research outcome, diagnostic red flags and pitfalls with diagnostic imaging, early magnetic resonance imaging changes, pathology and axonal loss, neuroprotection and childhood MS.

Asia↗
PubMed2004

Generalised myoclonus evolving into epilepsia partialis continua due to a cingulate gyrus lesion: case report and review of the literature.

A young Chinese male was admitted for a generalised tonic-clonic seizure preceded by a week-long history of fever. Subsequently, he developed continuous myoclonic jerks in all four limbs, with clear left sided predominance, and no accompanying clouding of consciousness. Contrast MRI of the brain demonstrated a venous angioma in the right cingulate gyrus. Over the next few days, the clinical picture evolved, with focal motor status involving primarily the left lower limb and the abdomen. These movements resolved with anticonvulsant therapy. This case illustrates generalised myoclonus arising from a focal brain abnormality. The epileptiform aetiology became obvious only after evolution into the typical features of a focal motor seizure and supportive neuroimaging. This demonstrates the protean manifestations of epileptic seizures which have been ascribed to the cingulate gyrus. The lack of clear declarative clinical and EEG features highlights the melding of the fields of epileptology and movement disorders.

Adult↗