Publications by authors named "Matthew Blahna"

Background: Tucatinib is an oral human epidermal growth factor receptor 2 (HER2)-directed therapy approved in combination with trastuzumab and capecitabine for use in patients with previously treated HER2+ metastatic breast cancer (MBC) with/without brain metastases (BM). To inform clinical decision-making, it is important to understand tucatinib use in real-world clinical practice. We describe patient characteristics, treatment patterns, and clinical outcomes for tucatinib treatment in the real-world setting.

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A systematic literature review and network meta-analysis of randomized controlled trials in patients receiving therapy for HER2+ unresectable/metastatic breast cancer after ≥1 HER2-directed therapy was conducted to compare progression-free survival (PFS) and overall survival (OS). Hazard ratios (HRs) and relative differences from fractional polynomials (FPs) for PFS and OS were assessed by Bayesian network meta-analyses. For PFS, surface under the cumulative rankogram (SUCRA) ranked tucatinib plus trastuzumab with capecitabine as highest in both HR and FP analyses, followed by T-DM1 monotherapy and neratinib plus capecitabine.

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During pneumococcal pneumonia, antibacterial defense requires the orchestrated expression of innate immunity mediators, initiated by alveolar macrophages and dependent on transcription driven by nuclear factor κB (NF-κB). Such immune pressure may select for pneumococci, which avoid or subvert macrophage NF-κB activation. Analyzing pneumococci collected from children in Massachusetts, we found that the activation of macrophage NF-κB by Streptococcus pneumoniae is highly diverse, with a preponderance of low NF-κB activators that associate particularly with complicated pneumonia.

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Although RNA interference (RNAi) has become a ubiquitous laboratory tool since its discovery 12 years ago, in vivo delivery to selected cell types remains a major technical challenge. Here, we report the use of lentiviral vectors for long-term in vivo delivery of RNAi selectively to resident alveolar macrophages (AMs), key immune effector cells in the lung. We demonstrate the therapeutic potential of this approach by RNAi-based downregulation of p65 (RelA), a component of the pro-inflammatory transcriptional regulator, nuclear factor κB (NF-κB) and a key participant in lung disease pathogenesis.

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Transcriptional control of microRNAs (miRNA) by cell signaling pathways, especially in the context of growth factor regulation, is a widely recognized phenomenon with broad-reaching implications. However, several recent studies indicate that not just transcription, but also processing of miRNAs is subject to regulation as part of an integrated physiological response to various stimuli and environmental changes. The canonical miRNA biogenesis pathway; sequential steps of nucleolytic cleavage by the RNase III enzymes Drosha and Dicer, are emerging regulatory hubs for the modulation of miRNA expression as part of both physiological and pathological responses.

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The Zcchc11 enzyme is implicated in microRNA (miRNA) regulation. It can uridylate let-7 precursors to decrease quantities of the mature miRNA in embryonic stem cell lines, suggested to mediate stem cell maintenance. It can uridylate mature miR-26 to relieve silencing activity without impacting miRNA content in cancer cell lines, suggested to mediate cytokine and growth factor expression.

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The acute phase response is an evolutionarily conserved reaction in which physiological stress triggers the liver to remodel the blood proteome. Although thought to be involved in immune defense, the net biological effect of the acute phase response remains unknown. As the acute phase response is stimulated by diverse cytokines that activate either NF-κB or STAT3, we hypothesized that it could be eliminated by hepatocyte-specific interruption of both transcription factors.

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microRNAs (miRNAs) are small non-coding RNAs conserved in metazoans. Depletion of miRNAs results in embryonic lethality, suggesting they are essential for embryogenesis. Similarly, pathways induced by growth factors of the transforming growth factor β (TGF-β) superfamily control cell growth, differentiation, and development.

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Zcchc11 is a uridyltransferase protein with enzymatic activity directed against diverse RNA species. On the basis of its known uridylation targets, we hypothesized that Zcchc11 might regulate cell proliferation. Confirming this, loss-of-function and complementary gain-of-function experiments consistently revealed that Zcchc11 promotes the transition from G(1) to S phase of the cell cycle.

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Mounting an effective host immune response without incurring inflammatory injury requires the precise regulation of cytokine expression. To achieve this, cytokine mRNAs are post-transcriptionally regulated by diverse RNA-binding proteins and microRNAs (miRNAs) targeting their 3' untranslated regions (UTRs). Zcchc11 (zinc-finger, CCHC domain-containing protein 11) contains RNA-interacting motifs, and has been implicated in signalling pathways involved in cytokine expression.

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Objectives: To describe the distribution of trimethoprim-sulfamethoxazole resistance genes and the role of horizontal gene transfer and clonal expansion in recent increases of antibiotic resistance rates among uropathogenic Escherichia coli in Europe and Canada.

Methods: We identified antibiotic resistance alleles sul1, sul2, sul3 and dfr along with type 1 and type 2 integrons among 350 uropathogenic E. coli isolates from a cross-sectional study of acute, uncomplicated, community-acquired urinary tract infections in 16 western European countries and Canada (ECOSENS).

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Background: Antibiotic resistance is increasingly complicating the management of urinary tract infection. We investigated the extent to which a group of Escherichia coli called clonal group A (CGA), which is associated with resistance to trimethoprim-sulfamethoxazole (TMP-SMZ), accounted for TMP-SMZ resistance among a prospectively collected set of uropathogenic and rectal E. coli isolates from a university population in Michigan.

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