Publications by authors named "Michael Lim"

Unlabelled: Patients who have radiographically detectable lesions in their brain or other symptoms compatible with brain tumors pose challenges for diagnosis. The only definitive way to diagnose such patients is through brain biopsy, an obviously invasive and dangerous procedure. Here we present a new workflow termed "CSF-BAM" that simultaneously identifies cell or T cell receptor rearrangements, neuploidy, and using PCR-mediated amplification of both strands of the DNA from CSF samples.

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  • Glioblastoma (GBM) is a difficult-to-treat brain cancer characterized by aggressive behavior and high rates of recurrence, with tumor-associated microglia and macrophages (TAM) playing a significant role in its immune microenvironment.
  • Researchers found that TAMs in the tumor core show higher ATP synthase expression and activity, leading to increased energy production and metabolic changes in the presence of GBM cells, which in turn stimulate tumor growth.
  • Targeting the signaling pathway involving elevated extracellular ATP (eATP) and the P2X purinoceptor 7 (P2X7R) has the potential to decrease tumor growth and improve survival rates in models of GBM, highlighting a new therapeutic strategy.
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Background: Glioblastoma is characterized by rapid tumor growth and high invasiveness. The tumor microenvironment of glioblastoma is highly immunosuppressive with both intrinsic and adaptive resistance mechanisms that result in disease recurrence despite current immunotherapeutic strategies.

Methods: In this systematic review of clinical trials involving immunotherapy for glioblastoma using ClinicalTrials.

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  • The left ventricular summit (LVS) is a key area where epicardial arrhythmias frequently occur, making it a significant focus for medical professionals.
  • Ablating arrhythmias at the LVS is particularly challenging due to its complicated anatomical structure and proximity to other vital heart areas.
  • This review provides an in-depth analysis of the LVS anatomy and offers a thorough overview of the techniques used for mapping and ablation of LVS-related arrhythmias.
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BRAF pediatric low-grade gliomas frequently transform into high-grade gliomas (HGG) and poorly respond to chemotherapy, resulting in high mortality. Although combined BRAF and MEK inhibition (BRAFi+MEKi) outperforms chemotherapy, ∼70% of BRAF HGG patients are therapy resistant and undergo unbridled tumor progression. BRAF glioma have an immune-rich microenvironment suggesting that they could be responsive to immunotherapy but effects of BRAFi+MEKi on anti-tumor immunity are unclear.

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Background And Objective: One of the uses of indocyanine green (ICG) in the surgical field is the evaluation of the anastomotic margins in colorectal surgery. This is of particular importance because fluorescence imaging may aid in detecting vascular compromise, allowing the surgeon to change the resection margin thereby decreasing the chance of an anastomotic leak. To date, there has been no study with its use locally.

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Community assembly provides the foundation for applications in biodiversity conservation, climate change, invasion, restoration and synthetic ecology. However, predicting and prioritising assembly outcomes remains difficult. We address this challenge via a mechanism-free approach useful when little data or knowledge exist (LOVE; Learning Outcomes Via Experiments).

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  • Rectal bleeding can signal both benign and serious conditions like colorectal cancer (CRC) and inflammatory bowel disease (IBD), making it crucial to assess its cause promptly.
  • The study reviewed 344 patients with isolated rectal bleeding and positive fecal immunochemical tests (FIT), finding 25.9% had significant bowel pathologies, including cancer and IBD, primarily located distal to the splenic flexure.
  • Flexible sigmoidoscopy (FS) is shown to be an effective initial diagnostic tool, allowing for better patient management by downgrading those without cancer to routine follow-ups, thus optimizing healthcare resources.
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  • Right ventricular dysfunction (RVD) affects 30-40% of patients experiencing acute myocardial infarction and cardiogenic shock, leading to concerns about their survival outcomes when treated with left ventricular mechanical support.
  • A study conducted across 80 sites analyzed 361 patients, finding that 28% had RVD, which correlated with lower survival rates to discharge (61.8% vs. 73.4%) and higher instances of severe shock and active CPR during treatment.
  • Despite initial lower survival for RVD patients, hemodynamic parameters measured within 24 hours showed no significant differences between those with and without RVD, indicating that early left ventricular support may not immediately affect RV function.
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  • * The exact cause of takotsubo cardiomyopathy is unclear, but theories suggest factors like high levels of stress hormones, microvascular issues, coronary spasms, or inflammation may play a role.
  • * A case study was presented of a patient with herpes simplex virus (HSV) encephalitis who developed takotsubo cardiomyopathy, which improved after treatment with acyclovir, emphasizing the need for doctors to consider this type of cardiomyopathy when diagnosing HSV encephalitis with respiratory symptoms. *
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Introduction: This is a prospective, rigorous inquiry into the systemic immune effects of standard adjuvant chemoradiotherapy, for WHO grade 4, glioblastoma. The purpose is to identify peripheral immunologic effects never yet reported in key immune populations, including myeloid-derived suppressor cells, which are critical to the immune suppressive environment of glioblastoma. We hypothesize that harmful immune-supportive white blood cells, myeloid derived suppressor cells, expand in response to conventionally fractionated radiotherapy with concurrent temozolomide, essentially promoting systemic immunity similar what is seen in chronic diseases like diabetes and heart disease.

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Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism.

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  • The field of interventional cardiology (IC) has seen significant advancements and improved training programs over the last 40 years, including accredited fellowship programs and subspecialty certification.
  • Despite these improvements, the application process for IC fellowships has been chaotic and inconsistent, causing stress and pressure on applicants due to competitive recruitment practices.
  • A task force from the Society for Cardiovascular Angiography & Interventions has initiated a grassroots movement to create a national Match system for IC fellowships, aiming to establish fairness and equity in the application process.
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Background And Objectives: Patients undergoing percutaneous rhizotomy for trigeminal neuralgia (TN) may require several procedures to manage their pain. However, it is not fully understood whether repeat procedures influence postoperative complication rates.

Methods: We retrospectively reviewed patients undergoing rhizotomy at our institution from 2011 to 2022.

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Tumor-infiltrating lymphocyte (TIL) hypofunction contributes to the progression of advanced cancers and is a frequent target of immunotherapy. Emerging evidence indicates that metabolic insufficiency drives T cell hypofunction during tonic stimulation, but the signals that initiate metabolic reprogramming in this context are largely unknown. Here, we found that Meteorin-like (METRNL), a metabolically active cytokine secreted by immune cells in the tumor microenvironment (TME), induced bioenergetic failure of CD8 T cells.

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  • A study was conducted to evaluate how the time from diagnosis to catheter ablation (DAT) affects the recurrence of atrial fibrillation (AF) in patients.
  • The trial involved 334 patients divided into quartiles based on their DAT, with results showing varying AF recurrence rates; longer DAT generally correlated with higher recurrence.
  • Despite this trend, overall quality of life improved significantly for all patients, indicating positive outcomes regardless of the length of the DAT, with only the longest DAT group showing a statistically significant risk of recurrence.
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Introduction: In 2022, the Minister for Health of Singapore launched Healthier SG, a national strategy in championing the shift towards a population health approach.

Method: The Singapore Heart Foundation conducted a series of roundtable discussions, also attended by representatives of the Singapore Cardiac Society and the Chapter of Cardiologists of the Academy of Medicine Singapore. During the meetings, the authors formulated interventions supportive of Healthier SG that specifically aimed to uplift the state of cardiovascular (CV) preventive care in Singapore.

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  • Doctors studied two treatments for a type of pain called TN. One is called SRS, and the other is glycerol rhizotomy. They wanted to see if having SRS first affects how well the rhizotomy works.
  • They looked at data from patients treated at their hospital between 2011 and 2022. They compared patients who had SRS before rhizotomy with those who only had the rhizotomy.
  • Results showed that patients who had SRS were more likely to continue feeling pain after the rhizotomy, especially soon after the surgery. They also found that older patients had better chances of success with the rhizotomy.
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Atrial fibrillation (AF), with its significant associated morbidity and mortality contributes to significant healthcare utilisation and expenditure. Given its progressively rising incidence, strategies to limit AF development and progression are urgently needed. Lifestyle modification is a potentially potent but underutilised weapon against the AF epidemic.

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Background: Linear and complex electrogram ablation (LCEA) beyond pulmonary vein isolation (PVI) is associated with an increase in left atrial macro-re-entrant tachycardias (LAMTs). Posterior wall isolation (PWI) is increasingly performed to improve AF ablation outcomes. However, the impact of PWI on the incidence of LAMT is unknown.

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Gliomas are primary brain tumours that are thought to develop from neural stem or progenitor cells that carry tumour-initiating genetic alterations. Based on microscopic appearance and molecular characteristics, they are classified according to the WHO classification of central nervous system (CNS) tumours and graded into CNS WHO grades 1-4 from a low to high grade of malignancy. Diffusely infiltrating gliomas in adults comprise three tumour types with distinct natural course of disease, response to treatment and outcome: isocitrate dehydrogenase (IDH)-mutant and 1p/19q-codeleted oligodendrogliomas with the best prognosis; IDH-mutant astrocytomas with intermediate outcome; and IDH-wild-type glioblastomas with poor prognosis.

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Objective: Recently, two scoring systems have been developed for predicting pain-free outcomes after microvascular decompression (MVD). Evaluation of these scores on large external datasets has been limited. In this study, the authors aimed to evaluate the performance of published MVD scoring systems in predicting pain-free outcome.

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Immunotherapy has revolutionized the treatment of cancers. Reinvigorating lymphocytes with checkpoint blockade has become a cornerstone of immunotherapy for multiple tumor types, but the treatment of glioblastoma has not yet shown clinical efficacy. A major hurdle to treat GBM with checkpoint blockade is the high degree of myeloid-mediated immunosuppression in brain tumors that limits CD8 T-cell activity.

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  • Stanford Health Care serves around 9 million people and has seen significant changes after opening a second hospital in late 2019 and the impact of the COVID-19 pandemic.
  • There was a notable increase in both laboratory tests (45%) and anatomic pathology (AP) cases (17%) following the pandemic, linked to a rise in hospital census driven by more emergency department admissions and longer patient stays.
  • The hospital reached overcapacity levels of 103% for AP cases and 114% for lab tests, leading to challenges in performing clinical activities, especially surgical procedures, prompting recommendations for improved operational efficiency in the post-pandemic landscape.
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