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result(s) for
"Hebert, Kyle M"
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A tyrosine phosphoregulatory system controls exopolysaccharide biosynthesis and biofilm formation in Vibrio cholerae
by
Rubin, Seth M.
,
Pagliai, Fernando A.
,
Singh, Praveen K.
in
Amino acids
,
Antibiotics
,
Bacteria
2020
Production of an extracellular matrix is essential for biofilm formation, as this matrix both secures and protects the cells it encases. Mechanisms underlying production and assembly of matrices are poorly understood. Vibrio cholerae, relies heavily on biofilm formation for survival, infectivity, and transmission. Biofilm formation requires Vibrio polysaccharide (VPS), which is produced by vps gene-products, yet the function of these products remains unknown. Here, we demonstrate that the vps gene-products vpsO and vpsU encode respectively for a tyrosine kinase and a cognate tyrosine phosphatase. Collectively, VpsO and VpsU act as a tyrosine phosphoregulatory system to modulate VPS production. We present structures of VpsU and the kinase domain of VpsO, and we report observed autocatalytic tyrosine phosphorylation of the VpsO C-terminal tail. The position and amount of tyrosine phosphorylation in the VpsO C-terminal tail represses VPS production and biofilm formation through a mechanism involving the modulation of VpsO oligomerization. We found that tyrosine phosphorylation enhances stability of VpsO. Regulation of VpsO phosphorylation by the phosphatase VpsU is vital for maintaining native VPS levels. This study provides new insights into the mechanism and regulation of VPS production and establishes general principles of biofilm matrix production and its inhibition.
Journal Article
The effect of histopathologic analysis and tissue cultures on inpatient management of cellulitis: a randomized control trial
by
Wang, Henry E.
,
Milani-Nejad, Nima
,
Caterino, Jeffrey M.
in
Adult
,
Aged
,
Anti-Bacterial Agents - therapeutic use
2024
Background: In the absence of a gold-standard diagnostic modality for cellulitis, sterile inflammatory disorders may be misdiagnosed as cellulitis. Objective: To determine the utility of skin biopsy and tissue culture for the diagnosis and management of patients admitted with a diagnosis of presumed cellulitis. Design: Pilot single-blind parallel group randomized controlled clinical trial in 56 patients with a primary diagnosis of presumed cellulitis. In the intervention group only, skin biopsy and tissue culture results were made available to the primary care team to guide diagnosis and management. Length of hospital stay and antibiotic use were evaluated as outcome measures. Results: Length of stay showed the greatest opportunity for further study as a primary outcome (intervention: 4, IQR (2–6) vs. control: 5 IQR (3–8) days;
p
= 0.124). Limitations: The COVID-19 pandemic placed limitations on participant enrollment and study duration; in addition, data was collected from a single medical center. Conclusion: This study demonstrates that length of stay and anti-pseudomonal antibiotic de-escalation are endpoints that may be influenced by biopsy and tissue culture results in presumed cellulitis patients; these outcomes warrant further study.
Journal Article
Dynamics of the Apostichopus californicus-associated flavivirus under suboxic conditions and organic matter amendment
by
Lim, Em G.
,
Vilanova-Cuevas, Brayan
,
Altera, Ashley K.
in
Apostichopus
,
Apostichopus californicus
,
Echinodermata
2023
Flaviviruses cause some of the most detrimental vertebrate diseases, yet little is known of their impacts on invertebrates. Microbial activities at the animal-water interface are hypothesized to influence viral replication and possibly contribute to pathology of echinoderm wasting diseases due to hypoxic stress. We assessed the impacts of enhanced microbial production and suboxic stress on Apostichopus californicus associated flavivirus (PcaFV) load in a mesocosm experiment. Organic matter amendment and suboxic stress resulted in lower PcaFV load, which also correlated negatively with animal mass loss and microbial activity at the animal-water interface. These data suggest that PcaFV replication and persistence was best supported in healthier specimens. Our results do not support the hypothesis that suboxic stress or microbial activity promote PcaFV replication, but rather that PcaFV appears to be a neutral or beneficial symbiont of Apostichopus californicus .
Journal Article
Overlap chronic GVHD is associated with adverse survival outcomes compared to classic chronic GVHD
2024
Chronic graft-versus-host-disease (cGVHD) is divided into two subtypes: classic (absence of acute GVHD features) and overlap cGVHD (‘ocGVHD’), in which both chronic and acute GVHD clinical features are present simultaneously. While worse outcomes with ocGVHD have been reported, there are few recent analyses. We performed a secondary analysis of data from the ABA2 trial (
N
= 185), in which detailed GVHD data were collected prospectively and systematically adjudicated. Analyses included cumulative incidence of classic versus ocGVHD, their specific organ manifestations, global disease severity scores, non-relapse mortality (NRM), disease-free survival (DFS) and overall survival (OS) in these two cGVHD subtypes. Of 92 patients who developed cGVHD, 35 were classified as ocGVHD. The 1-year cumulative incidence, organ involvement, and global severity of classic and ocGVHD were similar between ABA2 patients receiving CNI/MTX+placebo and CNI/MTX+abatacept; thus, cohorts were combined for ocGVHD evaluation. This analysis identified ocGVHD as having significantly higher severity at presentation and at maximum global severity compared to classic cGVHD. OS and DFS were significantly lower for ocGVHD versus classic cGVHD. OcGVHD is associated with increased cGVHD severity scores, and is associated with decreased OS and DFS compared to classic cGVHD, underscoring the high risks with this cGVHD subtype.
Journal Article
Oral Warfarin and the Thrombin Inhibitor Dabigatran Increase Blood Pressure in Rats: Hidden Danger of Anticoagulants?
by
Muni, Navin
,
Ivanov, Iouri
,
Ware, Kyle M.
in
Acetylcysteine - pharmacology
,
Animals
,
Anticoagulants - pharmacology
2015
BACKGROUND
Hypertension is a common comorbidity in patients with chronic kidney disease (CKD). We reported earlier that oral anticoagulants, including warfarin and dabigatran, may induce acute kidney injury. No effects of oral anticoagulants on blood pressure (BP) have been previously reported. The aim of this study was to examine in detail the relationship of anticoagulant therapy and BP in rats.
METHODS
Sham-operated and 5/6 nephrectomy rats were treated with different doses of oral anticoagulants (warfarin and dabigatran), superoxide scavenger N-acetylcysteine (NAC), vitamin K, and protease activated receptor 1 (PAR-1) inhibitor SCH79797. BP was measured by a tail cuff daily.
RESULTS
Warfarin and dabigatran both increased systolic BP in sham-operated and 5/6 nephrectomy rats in a dose-dependent manner. SCH79797 also increased systolic BP in a dose-dependent manner. Vitamin K prevented warfarin-induced increase in BP but did not affect BP when administered alone. NAC delayed the warfarin-associated increase in BP. Warfarin effects on BP were similar in 5/6 nephrectomy rats with different CKD stages.
CONCLUSIONS
Both warfarin and dabigatran increase systolic BP in rats. The mechanism of this effect is not clear, but our data suggest that it is related to decreased thrombin activity associated with anticoagulant treatment. The superoxide scavenger NAC delayed, but did not prevent, warfarin-induced hypertension.
Journal Article
STAT1 potentiates oxidative stress revealing a targetable vulnerability that increases phenformin efficacy in breast cancer
2021
Bioenergetic perturbations driving neoplastic growth increase the production of reactive oxygen species (ROS), requiring a compensatory increase in ROS scavengers to limit oxidative stress. Intervention strategies that simultaneously induce energetic and oxidative stress therefore have therapeutic potential. Phenformin is a mitochondrial complex I inhibitor that induces bioenergetic stress. We now demonstrate that inflammatory mediators, including IFNγ and polyIC, potentiate the cytotoxicity of phenformin by inducing a parallel increase in oxidative stress through STAT1-dependent mechanisms. Indeed, STAT1 signaling downregulates NQO1, a key ROS scavenger, in many breast cancer models. Moreover, genetic ablation or pharmacological inhibition of NQO1 using β-lapachone (an NQO1 bioactivatable drug) increases oxidative stress to selectively sensitize breast cancer models, including patient derived xenografts of HER2+ and triple negative disease, to the tumoricidal effects of phenformin. We provide evidence that therapies targeting ROS scavengers increase the anti-neoplastic efficacy of mitochondrial complex I inhibitors in breast cancer.
Complex I inhibition induces oxidative stress leading to cancer cell cytotoxicity. Here, the authors show, in breast cancer models, that inflammatory mediators can potentiate complex I inhibitor phenformin cytotoxicity through STAT1-mediated downregulation of the reactive oxygen species scavenger NQO1.
Journal Article
U.S. Adolescent and Adult Women’s Experiences Accessing and Using Toilets in Schools, Workplaces, and Public Spaces: A Multi-Site Focus Group Study to Inform Future Research in Bladder Health
2019
The World Health Organization recognizes access to clean and safe toilets as crucial for public health. This study explored U.S. adolescent and adult cisgender women’s lived experiences accessing toilets in schools, workplaces, and public spaces. As part of the Prevention of Lower Urinary Tract Symptoms (PLUS) Research Consortium, we conducted 44 focus groups with female participants (n = 360; ages 11–93). Focus groups were stratified by age (11–14, 15–17, 18–25, 26–44, 45–64, 65+) and conducted across 7 geographically diverse U.S. sites from July 2017–April 2018. Using a transdisciplinary approach, we conducted conventional qualitative coding informed by our PLUS conceptual framework and used content analysis processes to identify salient themes. Across settings, toilet access was restricted by “gatekeepers” (i.e., individuals who control access to toilets). In contrast, self-restricting toilet use (deciding not to use the toilet despite biologic need to urinate) was based on internalized norms to prioritize school and job responsibilities over urination. In public spaces, self-restricting use was largely in response to lack of cleanliness. Across the life course, participants perceived gender disparities in the ability to easily access public toilets. Further research is needed to determine if and how these factors impact bladder health across the life course.
Journal Article
Abatacept for the prevention of graft versus host disease in pediatric patients receiving 7/8 HLA-mismatched unrelated transplant for hematologic malignancies: a real-world analysis
by
Kean, Leslie S
,
Neuberg, Donna
,
Schoettler, Michelle L
in
Graft-versus-host reaction
,
Malignancy
,
Pediatrics
2023
Journal Article