Publications by authors named "Derek Soon"

Background: Immunity to SARS-CoV-2 vaccination and infection differs considerably among individuals. We investigate the critical pathways that influence vaccine-induced cross-variant serological immunity among individuals at high-risk of COVID-19 complications.

Methods: Neutralizing antibodies to the wild-type SARS-CoV-2 virus and its variants (Beta, Gamma, Delta and Omicron) were analyzed in patients with autoimmune diseases, chronic comorbidities (multimorbidity), and healthy controls.

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Background: In pre-vaccinated people with multiple sclerosis (MS), certain disease-modifying therapies (DMTs), particularly the anti-CD20 treatments, appear to be associated with an increased risk of COVID-19 infection and indeed with severe infection. It is still not known if such observations extend to vaccinated individuals and there have been considerably fewer studies in aquaporin-4-antibody neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein-antibody associated disease (MOGAD) patients. In this study, we investigated the rates of symptomatic COVID-19 infection in adult patients with MS, AQP4-NMOSD and MOGAD who had received 2 doses of SARS-CoV-2 mRNA vaccine.

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Central nervous system (CNS) infections cause substantial morbidity and mortality worldwide, with mounting concern about new and emerging neurologic infections. Stratifying etiologies based on initial clinical and laboratory data would facilitate etiology-based treatment rather than relying on empirical treatment. Here, we report the epidemiology and clinical outcomes of patients with CNS infections from a prospective surveillance study that took place between 2013 and 2016 in Singapore.

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Headaches are common in primary care. For safe assessment and management of the patient with headache, a focused history and physical examination are important to identify secondary headache, and find out whether an immediate referral to the emergency department or a non-emergent referral to the neurologist is warranted. The majority of patients with primary headache may be safely managed in the outpatient setting.

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Background: A considerable number of people with multiple sclerosis (pwMS) live in low- and middle-income countries (LMIC), where lack of resource adversely affects access to effective disease-modifying treatment.

Objective: The objective of this commentary is to propose a useful cost-effective disease-modifying treatment option for pwMS in LMIC with potential high efficacy and high convenience to the pwMS and treating physician.: We propose using generic 2-chloro-2'-deoxyadenosine (cladribine), a small molecule licensed for treatment of people with hairy cell leukaemia, as a solution of this significant equity imbalance.

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Stroke is a significant cause of death and disability in Singapore; in 2014, it was the fourth most common cause of death. Transient ischaemic attack (TIA) is defined as a transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia without evidence of acute infarction. The diagnosis of TIA/acute stroke needs to be considered in all patients who present with sudden focal neurological dysfunction.

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Background: Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS). Most study populations have combined intracranial and extracranial ICA occlusions for analysis; few have studied purely cervical ICA occlusions. We evaluated AIS patients with acute cervical ICA occlusion treated with IV-tPA to identify predictors of outcomes.

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Objective: We compared intracranial collaterals on pretreatment and day 2 brain CT angiograms (CTA) to assess their evolution and relationship with functional outcomes in acute ischemic stroke (AIS) patients treated with IV tissue plasminogen activator (tPA).

Methods: Consecutive AIS patients who underwent pretreatment and day 2 CTA and received IV tPA during 2010-2013 were included. Collaterals were evaluated by 2 independent neuroradiologists using 3 predefined criteria: the Miteff system, the Maas system, and 20-point collateral scale by the Alberta Stroke Program Early CT Score methodology.

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Inflammatory neuropathies have been reported to occur in association with nephrotic syndrome. Their underlying immuno-pathogenic mechanisms remain unknown. A 50-year-old woman concurrently presented with acute-onset chronic inflammatory demyelinating polyneuropathy and nephrotic syndrome secondary to focal segmental glomerulosclerosis.

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This article presents findings from a simulation-based interprofessional education (IPE) program involving trainee advanced practice nurses (APNs) and internal medicine residents (IMRs) based in Singapore. Trainee APNs and IMRs participated in a semester-long series of high-fidelity simulations of medical emergencies. Learners' attitudes toward the IPE intervention were assessed using validated Likert scaled surveys and written comments.

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Objective: Clinical and immunological evaluation of 'incomplete' Bickerstaff brainstem encephalitis (BBE).

Methods: We studied two patients with postinfectious brainstem syndromes who presented at National University Hospital Singapore. Laboratory work-up included measurement of antiganglioside antibodies.

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Natalizumab, an anti-alpha4 integrin antibody, significantly reduces the number of visibly enhancing multiple sclerosis (MS) lesions. In this substudy of a 2-year trial of natalizumab monotherapy versus placebo, contrast-enhanced imaging investigated for subtle blood brain barrier (BBB) leakage in relapsing remitting (RRMS) patients, and whether such leakage is modified by natalizumab. After 24 weeks on treatment, 40 patients from 3 centres (27 on natalizumab and 13 on placebo) were studied.

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