Publications by authors named "Clarissa Lim"

Article Synopsis
  • SARS-CoV-2 variants and reduced vaccine immunity have led to increased cases of breakthrough infections, highlighting the need to understand vaccine protection mechanisms.
  • Researchers analyzed mRNA vaccinated individuals in Singapore during the Omicron surge to compare immune responses.
  • Findings suggest those who stayed uninfected developed a stronger variant-specific IgA response after booster shots, indicating IgA may play an important role in protecting against Omicron.
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Waning antibody levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of variants of concern highlight the need for booster vaccinations. This is particularly important for the elderly population, who are at a higher risk of developing severe coronavirus disease 2019 (COVID-19) disease. While studies have shown increased antibody responses following booster vaccination, understanding the changes in T and B cell compartments induced by a third vaccine dose remains limited.

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Background: Over 2021, COVID-19 vaccination programs worldwide focused on raising population immunity through the primary COVID-19 vaccine series. In Singapore, two mRNA vaccines (BNT162b2 and mRNA-1273) and the inactivated vaccine CoronaVac are currently authorized under the National Vaccination Programme for use as the primary vaccination series. More than 90% of the Singapore population has received at least one dose of a COVID-19 vaccine as of December 2021.

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Article Synopsis
  • The study examines the efficacy of different COVID-19 vaccine booster combinations to enhance immune response against the Omicron variant, addressing concerns about decreasing antibody levels after vaccination and the emergence of variants.
  • A total of 100 individuals who initially received the BNT162b2 vaccine were randomly assigned to receive either a homologous booster (BBB) or a heterologous mRNA-1273 booster (BBM), with antibody levels measured 28 days after the booster.
  • Findings revealed that the heterologous booster (BBM) led to significantly higher levels of neutralizing antibodies compared to the homologous booster (BBB), particularly in older adults, highlighting the potential benefits of mixed vaccine approaches for improved protection against emerging variants.
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Alpha-ketoglutarate (AKG) is an intermediate in the Krebs cycle involved in various metabolic and cellular pathways. As an antioxidant, AKG interferes in nitrogen and ammonia balance, and affects epigenetic and immune regulation. These pleiotropic functions of AKG suggest it may also extend human healthspan.

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Human A adenosine receptor hAAR has been implicated in gastrointestinal cancer, where its cellular expression has been found increased, thus suggesting its potential as a molecular target for novel anticancer compounds. Observation made in our previous work indicated the importance of the carbonyl group of amide in the indolylpyrimidylpiperazine (IPP) for its human A adenosine receptor (hAAR) subtype binding selectivity over the other AR subtypes. Taking this observation into account, we structurally modified an indolylpyrimidylpiperazine (IPP) scaffold, (a non-selective adenosine receptors' ligand) into a modified IPP (mIPP) scaffold by switching the position of the carbonyl group, resulting in the formation of both ketone and tertiary amine groups in the new scaffold.

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