Publications by authors named "Dionne K"

HIV-1 envelope glycoproteins (Env) from primary HIV-1 isolates typically adopt a pretriggered "closed" conformation that resists to CD4-induced (CD4i) non-neutralizing antibodies (nnAbs) mediating antibody-dependent cellular cytotoxicity (ADCC). CD4-mimetic compounds (CD4mcs) "open-up" Env allowing binding of CD4i nnAbs, thereby sensitizing HIV-1-infected cells to ADCC. Two families of CD4i nnAbs, the anti-cluster A and anti-coreceptor binding site (CoRBS) Abs, are required to mediate ADCC in combination with the indane CD4mc BNM-III-170.

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The majority of naturally elicited antibodies against the HIV-1 envelope glycoproteins (Env) are non-neutralizing (nnAbs) because they are unable to recognize the Env trimer in its native "closed" conformation. Nevertheless, it has been shown that nnAbs have the potential to eliminate HIV-1-infected cells by antibody-dependent cellular cytotoxicity (ADCC) provided that Env is present on the cell surface in its "open" conformation. This is because most nnAbs recognize epitopes that become accessible only after Env interaction with CD4 and the exposure of epitopes that are normally occluded in the closed trimer.

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Natural Killer (NK) cells have the potential to eliminate HIV-1-infected cells by antibody-dependent cellular cytotoxicity (ADCC). NK cell activation is tightly regulated by the engagement of its inhibitory and activating receptors. The activating receptor CD16 drives ADCC upon binding to the Fc portion of antibodies; NK cell activation is further sustained by the co-engagement of activating receptors NTB-A and 2B4.

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The majority of naturally-elicited antibodies against the HIV-1 envelope glycoproteins (Env) are non-neutralizing (nnAbs), because they are unable to recognize the Env timer in its native "closed" conformation. Nevertheless, it has been shown that nnAbs have the potential to eliminate HIV-1-infected cells by Antibody-Dependent Cellular Cytotoxicity (ADCC) provided that Env is present on the cell surface in its "open" conformation. This is because most nnAbs recognize epitopes that become accessible only after Env interaction with CD4 and the exposure of epitopes that are normally occluded in the closed trimer.

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Acquired drug resistance to anticancer targeted therapies remains an unsolved clinical problem. Although many drivers of acquired drug resistance have been identified, the underlying molecular mechanisms shaping tumour evolution during treatment are incompletely understood. Genomic profiling of patient tumours has implicated apolipoprotein B messenger RNA editing catalytic polypeptide-like (APOBEC) cytidine deaminases in tumour evolution; however, their role during therapy and the development of acquired drug resistance is undefined.

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Since the beginning of the SARS-CoV-2 pandemic, several variants of concern (VOCs), such as the Alpha, Beta, Gamma, Delta and Omicron variants, have arisen and spread worldwide. Today, the predominant circulating subvariants are sublineages of the Omicron variant, which have more than 30 mutations in their Spike glycoprotein compared to the ancestral strain. The Omicron subvariants were significantly less recognized and neutralized by antibodies from vaccinated individuals.

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Positively selected germinal center B cells (GCBC) can either resume proliferation and somatic hypermutation or differentiate. The mechanisms dictating these alternative cell fates are incompletely understood. We show that the protein arginine methyltransferase 1 (Prmt1) is upregulated in murine GCBC by Myc and mTORC-dependent signaling after positive selection.

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Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants have recently emerged, becoming the dominant circulating strains in many countries. These variants contain a large number of mutations in their spike glycoprotein, raising concerns about vaccine efficacy. In this study, we evaluate the ability of plasma from a cohort of individuals that received three doses of mRNA vaccine to recognize and neutralize these Omicron subvariant spikes.

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COVID-19 convalescent plasmas (CCPs) are chosen for plasma therapy based on neutralizing titers and anti-Spike immunoglobulin levels. However, CCP characteristics that promote SARS-CoV-2 control are complex and incompletely defined. Using an in vivo imaging approach, we demonstrate that CCPs with low neutralizing (ID ≤ 1:250), but moderate to high Fc-effector activity, in contrast to those with poor Fc function, delay mortality and/or improve survival of SARS-CoV-2-challenged K18-hACE2 mice.

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Ethanol is a known vertebrate teratogen that causes craniofacial defects as a component of fetal alcohol syndrome (FAS). Our results show that sea urchin embryos treated with ethanol similarly show broad skeletal patterning defects, potentially analogous to the defects associated with FAS. The sea urchin larval skeleton is a simple patterning system that involves only two cell types: the primary mesenchymal cells (PMCs) that secrete the calcium carbonate skeleton and the ectodermal cells that provide migratory, positional, and differentiation cues for the PMCs.

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Background And Objectives: We present the case of a 67-year-old man who developed encephalopathy, headaches, and seizure activity after initiating treatment with the novel tyrosine kinase inhibitor, sitravatinib.

Methods: The patient was identified in routine clinical practice.

Results: Brain MRI revealed lobar microhemorrhages and bihemispheric vasogenic edema.

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Article Synopsis
  • Lorlatinib is the leading treatment for ALK-positive non-small cell lung cancer, but patients can develop various mutations that make the drug less effective.
  • After studying these mutations, researchers found that the most common ones were ALK G1202R and I1171N/S/T, which contribute to resistance against lorlatinib.
  • The team also discovered new lorlatinib analogs that are more effective against specific mutations, suggesting a need for personalized treatment plans based on the type of mutation found in patients.
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  • The study investigates how relative hypoglycemia and a new metric, hemoglobin A1c-adjusted time in blood glucose band (HA-TIB), relate to mortality rates in critically ill patients.
  • Over 3,600 ICU patients with various diabetes statuses were analyzed, with attention to their blood glucose levels and HbA1c readings during their hospital stay.
  • Results showed that higher time spent in the optimal glucose range (70-140 mg/dL) correlated with lower mortality, emphasizing the importance of managing blood sugar levels in intensive care settings.
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  • The study investigates how preadmission glycemic levels (HbA1c) and insulin treatment affect outcomes and mortality in critically ill patients admitted to ICU.
  • It categorizes 5,245 patients into three groups: those with diabetes on insulin treatment, those with diabetes not on insulin, and those without diabetes, analyzing their blood glucose levels and associated mortality rates.
  • Results show that higher HbA1c levels correlated with increased blood glucose and mortality risks, especially in patients not on insulin, suggesting that tailored glycemic management could improve patient outcomes in critical care settings.
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The complexity of the central nervous system (CNS) is not recapitulated in cell culture models. Thin slicing and subsequent culture of CNS tissue has become a valued means to study neuronal and glial biology within the context of the physiologically relevant tissue milieu. Modern membrane-interface slice culturing methodology allows for straightforward access to both CNS tissue and feeding medium, enabling experimental manipulations and analyses that would otherwise be impossible in vivo.

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We assessed antimicrobial resistance (AMR) in Neisseria gonorrhoeae in Nunavut, Canada, using remnant gonorrhea nucleic acid amplification test-positive urine specimens. This study confirms the feasibility of conducting N. gonorrhoeae AMR surveillance and highlights the diversity of gonococcal sequence types and geographic variation of AMR patterns in the territory.

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In B lymphocytes, the uracil N-glycosylase (UNG) excises genomic uracils made by activation-induced deaminase (AID), thus underpinning antibody gene diversification and oncogenic chromosomal translocations, but also initiating faithful DNA repair. mice develop B-cell lymphoma (BCL). However, since UNG has anti- and pro-oncogenic activities, its tumor suppressor relevance is unclear.

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Ribosomal (r)-proteins are generally viewed as ubiquitous, constitutive proteins that simply function to maintain ribosome integrity. However, findings in the past decade have led to the idea that r-proteins have evolved specialized functions beyond the ribosome. For example, the 40S ribosomal protein uS5 (RPS2) is known to form an extraribosomal complex with the protein arginine methyltransferase PRMT3 that is conserved from fission yeast to humans.

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Background: Orally administered sucrose is effective and safe in reducing pain intensity during single, tissue-damaging procedures in neonates, and is commonly recommended in neonatal pain guidelines. However, there is wide variability in sucrose doses examined in research, and more than a 20-fold variation across neonatal care settings. The aim of this study was to determine the minimally effective dose of 24% sucrose for reducing pain in hospitalized neonates undergoing a single skin-breaking heel lance procedure.

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We examined categorical agreement between automated mycobacterial susceptibility testing methods (Mycobacterial Growth Indicator Tube [MGIT] 960 System and the VersaTREK Mycobacteria Detection and Susceptibility System) which are based on single critical concentration (CC) "breakpoints" and a commercial microbroth dilution method (Sensititre Mycobacterium tuberculosis MIC Plate [MYCOTB]) which provides an MIC value. Mycobacterium tuberculosis isolates (n=355) were tested against three first-line antimycobacterial agents (ethambutol [EMB], isoniazid [INH], rifampin [RIF]) using the MYCOTB plate and either the MGIT 960 (site 1, n=142) or VersaTREK (site 2, n=213) systems. Overall categorical agreement was 96.

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Collaborative leadership and management structures are critical to transforming care delivery. Both nurse and physician managers are uniquely positioned to co-lead. However, little is known on how to prepare and support individuals for these co-leader arrangements.

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Article Synopsis
  • Mycobacterium cosmeticum, originally linked to cosmetic procedures and a nail salon outbreak, has been found resistant to multiple antibiotics in a new strain isolated from the Chesapeake Bay.
  • Researchers collected surface water samples from various sites to study microbial diversity and antibiotic resistance, focusing on areas near agricultural and industrial contamination.
  • The resistant strain displayed significant resistance to several antibiotics, with only fluoroquinolones, linezolid, and amikacin exhibiting effective activity, prompting questions about the reasons for the differing susceptibility patterns and the emergence of resistance.
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