Plasma amyloid beta peptides and oligomers antibodies in Alzheimer's disease

INTRODUCTION: Various forms of amyloid beta (Aβ) including Aβ peptides, oligomers, protofibrils and fibrils are thought to be pathogenic in Alzheimer’s disease (AD). The exact pathophysiological role of endogenous Aβ autoantibodies (Ab) in healthy subjects and AD patients are uncertain. Potential protective role ...published_or_final_versio

Adiponectin is protective against oxidative stress-induced cytotoxicity in amyloid-beta neurotoxicity

Oral PresentationBeta-amyloid (Aβ) neurotoxicity is important in Alzheimer’s disease (AD) pathogenesis. Aβ neurotoxicity causes oxidative stress, inflammation, and mitochondrial damage resulting in neuronal degeneration and death. Oxidative stress, inflammation, and mitochondrial failure are also pathophysiological mechanisms of type 2 diabetes mellitus (T2DM) which is characterised by insulin resistance. Interestingly, T2DM increases risk to develop AD which is associated with reduced neuronal insulin sensitivity (central insulin resistance). We studied the potential protective effect of adipon…published_or_final_versio

Cognitive impairment in adiponectin-knockout mice

Oral Presentationpublished_or_final_versio

Heart and liver R2 and R2* measurements in patients with thalassaemia major at 3T

Myocardial Tissue Characterization: Fat, Hemorrhage & Edema - Poster presentationTo determine the feasibility of measurements of transverse relaxation times for assessment of tissue iron overload at high field, we compared results of determinations of R2 and R2* using breathhold multi-echo spin-echo (MESE) and multi-echo gradient echo (MEGE) sequences, respectively, at 3T and at 1.5T in normal subjects and patients with thalassaemia major. Our results, the first reported measurements of R2 at both 3T and 1.5T in iron overloaded patients, demonstrate significant correlations in heart and liver at the two field strengths. These results provide evidence that myocardial and hepatic R2 can be measured at 3T as indicators of iron overload.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 375

Omicron variant susceptibility to neutralizing antibodies induced in children by natural SARS-CoV-2 infection or COVID-19 vaccine

The novel SARS-CoV-2 Omicron variant may increase the risk of re-infection and vaccine breakthrough infections as it possesses key mutations in the spike protein that affect neutralizing antibody response. Most studies on neutralization susceptibility were conducted using specimens from adult COVID-19 patients or vaccine recipients. However, since the paediatric population has an antibody response to SARS-CoV-2 infection that is distinct from the adult population, it is critical to assess the neutralization susceptibility of pediatric serum specimens. This study compared the neutralization susceptibility of serum specimens collected from 49 individuals of <18 years old, including 34 adolescent BNT162b2 (Pfizer-BioNTech) vaccine recipients, and 15 recovered COVID-19 patients aged between 2 and 17. We demonstrated that only 38.2% of BNT162b2 vaccine recipients and 26.7% of recovered COVID-19 patients had their serum neutralization titre at or above the detection threshold in our live virus microneutralization assay. Furthermore, the neutralizing antibody titer against the Omicron variant was substantially lower than those against the ancestral virus or the Beta variant. Our results suggest that vaccine recipients and COVID-19 patients in the pediatric age group will likely be more susceptible to vaccine breakthrough infections or reinfections due to the Omicron variant than previous variants

Epidemiology and Trends of Infective Meningitis in Neonates and Infants Less than 3 Months Old in Hong Kong

Objectives: Meningitis in neonates and young infants leads to significant morbidity and mortality worldwide. This study aimed to investigate pathogens, antibiotic resistance and secular change of incidence in Hong Kong. Methods: A retrospective search was performed on meningitis in neonates and infants aged <3 months in three Hong Kong public hospitals from 2004 to 2019. Medical charts were reviewed, with focus on the identification and antibiotic resistance of the pathogens. Results: A total of 200 cases of meningitis were identified (67% were bacterial). Group B Streptococcus (GBS) and Escherichia coli (E. coli) were the commonest bacterial pathogens. The annual rates of early-onset GBS meningitis decreased after the implementation of universal GBS screening and intrapartum antibiotic prophylaxis (IAP) in 2012, while that of late-onset GBS meningitis remained similar. A significant portion of E. coli isolates were resistant to ampicillin and/or gentamicin. Conclusion: GBS and E. coli were the most common bacteria for meningitis in this age group. The annual rate of bacterial meningitis in Hong Kong has declined in recent years, which has been attributed to the decline in early-onset GBS meningitis due to universal GBS screening and IAP. Antimicrobial-resistant bacterial strains that cause meningitis require further clinical and public health attention

Clinical Characteristics and Transmission of COVID-19 in Children and Youths During 3 Waves of Outbreaks in Hong Kong

IMPORTANCE: Schools were closed intermittently across Hong Kong to control the COVID-19 outbreak, which led to significant physical and psychosocial problems among children and youths. OBJECTIVE: To compare the clinical characteristics and sources of infection among children and youths with COVID-19 during the 3 waves of outbreaks in Hong Kong in 2020. DESIGN, SETTING AND PARTICIPANTS: This cross-sectional study involved children and youths aged 18 years or younger with COVID-19 in the 3 waves of outbreaks from January 23 through December 2, 2020. Data were analyzed from December 2020 through January 2021. MAIN OUTCOMES AND MEASURES: Demographic characteristics, travel and contact histories, lengths of hospital stay, and symptoms were captured through the central electronic database. Individuals who were infected without recent international travel were defined as having domestic infections. RESULTS: Among 397 children and youths confirmed with COVID-19 infections, the mean (SD) age was 9.95 (5.34) years, 220 individuals (55.4%) were male, and 154 individuals (38.8%) were asymptomatic. There were significantly more individuals who were infected without symptoms in the second wave (59 of 118 individuals [50.0%]) and third wave (94 of 265 individuals [35.5%]) than in the first wave (1 of 14 individuals [7.1%]) (P = .001). Significantly fewer individuals who were infected in the second and third waves, compared with the first wave, had fever (first wave: 10 individuals [71.4%]; second wave: 22 individuals [18.5%]; third wave: 98 individuals [37.0%]; P < .001) or cough (first wave: 6 individuals [42.9%]; second wave: 15 individuals [12.7%]; third wave: 52 individuals [19.6%]; P = .02). Among all individuals, 394 individuals (99.2%) had mild illness. One patient developed chilblains (ie, COVID toes), 1 patient developed multisystem inflammatory syndrome in children, and 1 patient developed post–COVID-19 autoimmune hemolytic anemia. In all 3 waves, 204 patients with COVID-19 (51.4%) had domestic infections. Among these individuals, 186 (91.2%) reported having a contact history with another individual with COVID-19, of which most (183 individuals [90.0%]) were family members. In the third wave, 18 individuals with domestic infections had unknown contact histories. Three schoolmates were confirmed with COVID-19 on the same day and were reported to be close contacts. CONCLUSIONS AND RELEVANCE: his cross-sectional study found that nearly all children and youths with COVID-19 in Hong Kong had mild illness. These findings suggest that household transmission was the main source of infection for children and youths with domestic infections and that the risk of being infected at school was small

COVID-19 In Children Across Three Asian Cosmopolitan Regions

As another wave of COVID-19 outbreak has approached in July 2020, a larger scale COVID-19 pediatric Asian cohort summarizing the clinical observations is warranted. Children confirmed with COVID-19 infection from the Republic of Korea, the Hong Kong Special Administrative Region (HKSAR) and Wuhan, China, during their first waves of local outbreaks were included. Their clinical characteristics and the temporal sequences of the first waves of local paediatric outbreaks were compared. Four hundred and twenty three children with COVID-19 were analyzed. Wuhan had the earliest peak, followed by Korea and HKSAR. Compared with Korea and Wuhan, patients in HKSAR were significantly older (mean age: 12.9 vs. 10.8 vs. 6.6 years, p < 0.001, respectively) and had more imported cases (87.5% vs. 16.5% vs. 0%, p < 0.001, respectively). The imported cases were also older (13.4 vs. 7.6 years, p < 0.001). More cases in HKSAR were asymptomatic compared to Korea and Wuhan (45.5% vs. 22.0% vs. 20.9%, p < 0.001, respectively), and significantly more patients from Wuhan developed fever (40.6% vs. 29.7% vs. 21.6%, p=0.003, respectively). There were significantly less imported cases than domestic cases developing fever after adjusting for age and region of origin (p = 0.046). 5.4% to 10.8% of patients reported anosmia and ageusia. None developed pediatric multisystem inflammatory syndrome temporally associated with SARS-CoV-2 (PMIS-TS). In general, adolescents were more likely to be asymptomatic and less likely to develop fever, but required longer hospital stays. In conclusion, majority patients in this pediatric Asian cohort had a mild disease. None developed PIMS-TS. Their clinical characteristics were influenced by travel history and age