Publications by authors named "Daniel Lachance"

Article Synopsis
  • This study focuses on the classification of glioma cases at Lagos University Teaching Hospital, utilizing the 2021 WHO brain tumor classification that combines histomorphology and molecular features, despite limited resources.
  • Of the 56 brain tumor cases examined, 52 were assessed, revealing that 35% of the initial diagnoses changed after applying the WHO criteria, with some diagnoses being upgraded and others downgraded.
  • The results emphasize the importance of molecular testing in improving brain tumor diagnoses in resource-limited settings like Nigeria and highlight the challenges faced in global health disparities in neuro-oncology.
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  • Crystal-storing histiocytosis (CSH) is a rare condition where abnormal protein crystals accumulate in the body, and when it affects the CNS, it can cause persistent imaging abnormalities.* -
  • The study describes one local case of CNS CSH alongside 10 other cases, noting that 9 had brain parenchyma involvement and some cases were linked to conditions like lymphoma.* -
  • While CNS CSH is uncommon, comprehensive evaluation for related malignancies is crucial, and treatment focuses on addressing these underlying conditions.*
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Measles virus (MV) vaccine strains have shown significant preclinical antitumor activity against glioblastoma (GBM), the most lethal glioma histology. In this first in human trial (NCT00390299), a carcinoembryonic antigen-expressing oncolytic measles virus derivative (MV-CEA), was administered in recurrent GBM patients either at the resection cavity (Group A), or, intratumorally on day 1, followed by a second dose administered in the resection cavity after tumor resection on day 5 (Group B). A total of 22 patients received study treatment, 9 in Group A and 13 in Group B.

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  • Glioma is a rare but aggressive brain tumor, with familial glioma being a genetically influenced form that makes up about 5% of cases.
  • Researchers conducted whole-genome sequencing on 203 individuals from 189 families with familial glioma, also validating findings in a separate group of 122 individuals.
  • The study identified significant variants in seven genes, particularly affecting tumor cell proliferation, highlighting the importance of these genes in understanding familial glioma.
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  • - Meningiomas are the most common primary brain tumors in adults, and atypical (grade 2) types have a moderate risk of returning after surgery; identifying molecular markers can help in managing patients post-surgery.
  • - A study analyzed tumor samples from 63 patients with grade 2 meningiomas who underwent complete surgical removal, using various genomic techniques to understand how these features relate to long-term outcomes.
  • - The findings revealed that specific genetic changes (like certain copy number variants) were closely linked to worse recurrence-free survival, suggesting that these genetic profiles should be included in patient management strategies after surgery.
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Background: Recurrent Stroke-Like Episodes of transient negative neurologic symptoms are a long-term consequence of cranial radiation therapy (RT) that may lead to significant functional impairment and worsen quality of life. We assessed management patterns and clinical course at our institution to assess optimal management strategy and understand long-term outcomes.

Methods: We conducted a retrospective review of all patients with recurrent negative neurologic symptoms after cranial RT who were treated at Mayo Clinic (Rochester), with follow-up extending through October 2021 with a goal of assessing for clinical change in the setting of medical management.

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  • Establishing causal links between genetic variants and cancer risk is complicated, but this study highlights the single-nucleotide polymorphism rs55705857, which significantly increases the risk of low-grade glioma (LGG).
  • The research identifies rs55705857 as the causal variant influencing molecular pathways related to LGG, specifically by disrupting OCT2/4 binding within a brain-specific enhancer, leading to greater gene expression.
  • Animal experiments show that altering the corresponding mouse gene accelerated tumor development, demonstrating the variant's role in hereditary susceptibility to severe gliomas in approximately 40% of LGG patients.
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Article Synopsis
  • Recent advancements in the understanding of inherited and acquired genetics related to adult diffuse glioma have revealed specific germline variants linked to different tumor subtypes, particularly glioblastoma (GBM) and lower-grade gliomas.
  • Genomewide association studies (GWAS) have identified significant associations that help stratify glioma risks, but findings have largely been limited to European populations.
  • The study emphasizes the need for more research in diverse populations to ensure that genetic risk models are applicable to various genetic ancestries across the board.
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Gastrointestinal motility is regulated by a variety of environmental factors including gut microbes and metabolites. The ability to interrogate mouse models of gut motility has enabled elucidation of these relationships. Here we describe integration of the red carmine dye and fluorescence isothiocyanate-dextran marker-based assays for characterizing gut transit with spatial resolution, along with an optional intracolonic infusion protocol for studying the effects of metabolites on colonic transit.

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Gut motility is regulated by the microbiome via mechanisms that include bile acid metabolism. To localize the effects of microbiome-generated bile acids, we colonized gnotobiotic mice with different synthetic gut bacterial communities that were metabolically phenotyped using a functional screen. Using two different marker-based assays of gut transit, we inferred that bile acids exert effects on colonic transit.

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COVID-19 (coronavirus disease 2019) patients exhibiting gastrointestinal symptoms are reported to have worse prognosis. Ace2 (angiotensin-converting enzyme 2), the gene encoding the host protein to which SARS-CoV-2 spike proteins bind, is expressed in the gut and therefore may be a target for preventing or reducing severity of COVID-19. Here we test the hypothesis that Ace2 expression in the gastrointestinal and respiratory tracts is modulated by the microbiome.

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Background Missing MRI sequences represent an obstacle in the development and use of deep learning (DL) models that require multiple inputs. Purpose To determine if synthesizing brain MRI scans using generative adversarial networks (GANs) allows for the use of a DL model for brain lesion segmentation that requires T1-weighted images, postcontrast T1-weighted images, fluid-attenuated inversion recovery (FLAIR) images, and T2-weighted images. Materials and Methods In this retrospective study, brain MRI scans obtained between 2011 and 2019 were collected, and scenarios were simulated in which the T1-weighted images and FLAIR images were missing.

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Neurolymphomatosis (NL) is a rare manifestation of lymphoma, with limited evidence for optimal management. The largest patient series, 50 cases of lymphoma and leukemia, was published in 2010 with limited rituximab exposure. This study aims to evaluate the clinical presentation, diagnostic testing, and outcomes of NL in the rituximab era.

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Growing evidence indicates a role for the gut microbiota in modulating anti-tumor treatment efficacy in human cancer. Here we study mucosa-associated invariant T (MAIT) cells to look for evidence of bacterial antigen recognition in human colon, lung, and kidney carcinomas. Using mass cytometry and single-cell mRNA sequencing, we identify a tumor-infiltrating MAIT cell subset expressing CD4 and Foxp3 and observe high expression of CD39 on MAIT cells from colorectal cancer (CRC) only, which we show to be expressed specifically after TCR stimulation.

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Article Synopsis
  • - Oligodendroglioma diagnosis relies on detecting IDH mutations and 1p/19q codeletion, but traditional FISH testing can inaccurately show partial codeletions as positive, leading to false-positive results.
  • - Researchers used chromosomal microarray data to assess the frequency of false positives in FISH codeletion tests and found a 3.6% misdiagnosis rate.
  • - The study recommends careful testing and interpretation of 1p/19q codeletion results, especially when there are inconsistencies between FISH and histopathological findings, to minimize misdiagnosis risks.
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Background: We assessed glioma incidence and disparities in postglioma survival rate in the Olmsted County, Minnesota, population.

Methods: This population-based study assessed the incidence of pathologically confirmed primary gliomas between January 1, 1995, and December 31, 2014. Age- and sex-adjusted incidence rates per 100 000 person-years were calculated and standardized to the US white 2010 population.

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Background: Twenty-five germline variants are associated with adult diffuse glioma, and some of these variants have been shown to be associated with particular subtypes of glioma. We hypothesized that additional germline variants could be identified if a genome-wide association study (GWAS) were performed by molecular subtype.

Methods: A total of 1320 glioma cases and 1889 controls were used in the discovery set and 799 glioma cases and 808 controls in the validation set.

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Importance: Per the World Health Organization 2016 integrative classification, newly diagnosed glioblastomas are separated into isocitrate dehydrogenase gene 1 or 2 (IDH)-wild-type and IDH-mutant subtypes, with median patient survival of 1.2 and 3.6 years, respectively.

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Purpose: Glioblastoma is the most frequent and lethal primary brain tumor. Development of novel therapies relies on the availability of relevant preclinical models. We have established a panel of 96 glioblastoma patient-derived xenografts (PDX) and undertaken its genomic and phenotypic characterization.

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Introduction: Glial fibrillary acidic protein (GFAP) immunoglobulin G is a recently discovered biomarker of an autoimmune central nervous system disorder characterized by a steroid-responsive meningoencephalomyelitis.

Case Report: A 63-year-old man with rheumatoid arthritis on etanercept presented with steroid-responsive subacute encephalopathy and foot drop. Brain and sural nerve biopsies demonstrated a T-cell perivascular infiltrate.

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Background: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The core of standard of care for newly diagnosed GBM was established in 2005 and includes maximum feasible surgical resection followed by radiation and temozolomide, with subsequent temozolomide with or without tumor-treating fields. Unfortunately, nearly all patients experience a recurrence.

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Background: Cognitive function is an important outcome measure in many brain tumor clinical trials, and investigators are interested in employing the most efficient methods of cognitive assessment for this purpose. Computerized testing can be appealing because of the perceived ease of use and electronic data generated. Traditional tests may have the advantage of accumulated validity evidence and comparability across historic trials.

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Background: Glioblastoma (GBM) represents an aggressive cancer type with a median survival of only 14 months. With fewer than 5% of patients surviving 5 years, comprehensive profiling of these rare patients could elucidate prognostic biomarkers that may confer better patient outcomes. We utilized multiple molecular approaches to characterize the largest patient cohort of isocitrate dehydrogenase (IDH)-wildtype GBM long-term survivors (LTS) to date.

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