6 results on '"Sarah B. Mueller"'
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2. Case 3-2023: A 16-Year-Old Girl with Abdominal Pain and Bloody Diarrhea
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Stacy A. Kahn, Maureen M. Leonard, Sjirk J. Westra, Jonathan S. Hausmann, and Sarah B. Mueller
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General Medicine - Published
- 2023
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3. Placental Vascular Abnormalities in Association With Prenatal and Long-Term Health Characteristics Among HIV-Exposed Uninfected Adolescents and Young Adults
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Isabel Zheng, Autumn Boutin, Chelsea S Pan, Lindsay T Fourman, Drucilla J. Roberts, Takara L. Stanley, Marisa E Gerard, and Sarah B. Mueller
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medicine.medical_specialty ,Adolescent ,Placenta ,HIV Infections ,Article ,Cohort Studies ,Pulmonary Disease, Chronic Obstructive ,Young Adult ,Pregnancy ,medicine ,Humans ,Pharmacology (medical) ,Pregnancy Complications, Infectious ,Young adult ,Reactive airway disease ,Fetus ,Obstetrics ,business.industry ,Gestational age ,medicine.disease ,Infectious Diseases ,medicine.anatomical_structure ,Cohort ,Female ,business ,Body mass index - Abstract
BACKGROUND HIV-exposed uninfected (HEU) individuals are predisposed to adverse health outcomes, which in part may stem from the influence of an altered intrauterine milieu on fetal programming. The placenta serves as a readout for the effects of the maternal environment on the developing fetus and may itself contribute to the pathogenesis of disease. SETTING US academic health system. METHODS We leveraged a previously established registry-based cohort of HEU adolescents and young adults to identify 26 subjects for whom placental histopathology was available. We further obtained placental tissue from 29 HIV-unexposed pregnancies for comparison. We examined differences in placental histopathology between the groups and related villous vascularity in the HEU group to prenatal maternal characteristics and long-term health outcomes. RESULTS Placentas from HEU pregnancies demonstrated a higher blood vessel count per villus as compared with controls (5.9 ± 1.0 vs. 5.4 ± 0.8; P = 0.05), which was independent of maternal prenatal age, race, body mass index, smoking status, hemoglobin, and gestational age. Furthermore, within the HEU group, lower CD4+ T-cell count during pregnancy was associated with greater placental vascularity (r = -0.44; P = 0.03). No significant relationships were observed between placental blood vessel count per villus and body mass index z-score or reactive airway disease among HEU individuals later in life. CONCLUSIONS Placentas from HEU pregnancies demonstrated increased villous vascularity compared with HIV-unexposed controls in proportion to the severity of maternal immune dysfunction. Further studies are needed to examine intrauterine exposure to hypoxia as a potential mechanism of fetal programming in HIV.
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- 2021
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4. Phosphorylation of Threonine 794 on Tie1 by Rac1/PAK1 Reveals a Novel Angiogenesis Regulatory Pathway.
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Jessica L Reinardy, Daniel M Corey, Christelle Golzio, Sarah B Mueller, Nicholas Katsanis, and Christopher D Kontos
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Medicine ,Science - Abstract
The endothelial receptor tyrosine kinase (RTK) Tie1 was discovered over 20 years ago, yet its precise function and mode of action remain enigmatic. To shed light on Tie1's role in endothelial cell biology, we investigated a potential threonine phosphorylation site within the juxtamembrane domain of Tie1. Expression of a non-phosphorylatable mutant of this site (T794A) in zebrafish (Danio rerio) significantly disrupted vascular development, resulting in fish with stunted and poorly branched intersomitic vessels. Similarly, T794A-expressing human umbilical vein endothelial cells formed significantly shorter tubes with fewer branches in three-dimensional Matrigel cultures. However, mutation of T794 did not alter Tie1 or Tie2 tyrosine phosphorylation or downstream signaling in any detectable way, suggesting that T794 phosphorylation may regulate a Tie1 function independent of its RTK properties. Although T794 is within a consensus Akt phosphorylation site, we were unable to identify a physiological activator of Akt that could induce T794 phosphorylation, suggesting that Akt is not the physiological Tie1-T794 kinase. However, the small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1), which is required for angiogenesis and capillary morphogenesis, was found to associate with phospho-T794 but not the non-phosphorylatable T794A mutant. Pharmacological activation of Rac1 induced downstream activation of p21-activated kinase (PAK1) and T794 phosphorylation in vitro, and inhibition of PAK1 abrogated T794 phosphorylation. Our results provide the first demonstration of a signaling pathway mediated by Tie1 in endothelial cells, and they suggest that a novel feedback loop involving Rac1/PAK1 mediated phosphorylation of Tie1 on T794 is required for proper angiogenesis.
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- 2015
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5. Brincidofovir (CMX001) Toxicity Associated With Epithelial Apoptosis and Crypt Drop Out in a Hematopoietic Cell Transplant Patient: Challenges in Distinguishing Drug Toxicity From GVHD
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Sarah B. Mueller, Claire J. Detweiler, Anthony D. Sung, Vinod K. Prasad, Jennifer L. Saullo, and Diana M. Cardona
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Male ,0301 basic medicine ,medicine.medical_specialty ,Colon ,Adenoviridae Infections ,medicine.medical_treatment ,030106 microbiology ,Organophosphonates ,Graft vs Host Disease ,Octreotide ,Brincidofovir ,Hematopoietic stem cell transplantation ,Gastroenterology ,Article ,Adenoviridae ,Cytosine ,03 medical and health sciences ,chemistry.chemical_compound ,Internal medicine ,medicine ,Humans ,Viremia ,Autografts ,business.industry ,Hematopoietic Stem Cell Transplantation ,Hematology ,medicine.disease ,Hematochezia ,Transplantation ,Graft-versus-host disease ,Oncology ,chemistry ,Child, Preschool ,Pediatrics, Perinatology and Child Health ,Toxicity ,medicine.symptom ,business ,Medulloblastoma ,Cidofovir ,medicine.drug - Abstract
Brincidofovir (CMX001) is an oral agent with activity against double-strand DNA viruses undergoing clinical trials in immunocompromised patients. We report a patient clinically diagnosed with brincidofovir-related gastrointestinal (GI) toxicity and his histologic findings. A 2-year-old boy with medulloblastoma undergoing autologous hematopoietic cell transplantation developed adenovirus viremia 9 days posttransplant. After initial treatment with intravenous cidofovir he was started on oral brincidofovir as part of a clinical trial. He developed hematochezia, anorexia, and emesis 11 weeks later. Sigmoid colon biopsy showed marked crypt drop out, moderate epithelial apoptosis, and lamina propria edema. The pathologic diagnosis was drug-related injury versus infection. Brincidofovir toxicity was diagnosed clinically and the drug was discontinued. His GI symptoms improved in 2 weeks with supportive care and octreotide. Brincidofovir causes GI toxicity and histologically demonstrates epithelial apoptosis and crypt injury, similar to graft versus host disease and mycophenolate mofetil toxicity.
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- 2018
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6. BAG3 (Bcl-2–Associated Athanogene-3) Coding Variant in Mice Determines Susceptibility to Ischemic Limb Muscle Myopathy by Directing Autophagy
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Douglas A. Marchuk, Espen E. Spangenburg, Thomas D. Green, Sehoon Keum, Ayotunde O. Dokun, Joseph M. McClung, Christopher D. Kontos, Timothy J. McCord, Jessica L. Reinardy, Christopher D. Lascola, Brian H. Annex, Cameron A. Schmidt, Sarah B. Mueller, Terence E. Ryan, Talaignair N. Venkatraman, and Kevin W. Southerland
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0301 basic medicine ,Pathology ,medicine.medical_specialty ,Necrosis ,business.industry ,Ischemia ,Skeletal muscle ,Critical limb ischemia ,Hindlimb ,Anatomy ,medicine.disease ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Physiology (medical) ,Heat shock protein ,medicine ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,Myopathy ,business ,Perfusion - Abstract
Background: Critical limb ischemia is a manifestation of peripheral artery disease that carries significant mortality and morbidity risk in humans, although its genetic determinants remain largely unknown. We previously discovered 2 overlapping quantitative trait loci in mice, Lsq-1 and Civq-1 , that affected limb muscle survival and stroke volume after femoral artery or middle cerebral artery ligation, respectively. Here, we report that a Bag3 variant (Ile81Met) segregates with tissue protection from hind-limb ischemia. Methods: We treated mice with either adeno-associated viruses encoding a control (green fluorescent protein) or 2 BAG3 (Bcl-2–associated athanogene-3) variants, namely Met81 or Ile81, and subjected the mice to hind-limb ischemia. Results: We found that the BAG3 Ile81Met variant in the C57BL/6 (BL6) mouse background segregates with protection from tissue necrosis in a shorter congenic fragment of Lsq-1 (C.B6– Lsq1-3 ). BALB/c mice treated with adeno-associated virus encoding the BL6 BAG3 variant (Ile81; n=25) displayed reduced limb-tissue necrosis and increased limb tissue perfusion compared with Met81- (n=25) or green fluorescent protein– (n=29) expressing animals. BAG3 Ile81 , but not BAG3 Met81 , improved ischemic muscle myopathy and muscle precursor cell differentiation and improved muscle regeneration in a separate, toxin-induced model of injury. Systemic injection of adeno-associated virus–BAG3 Ile81 (n=9), but not BAG3 Met81 (n=10) or green fluorescent protein (n=5), improved ischemic limb blood flow and limb muscle histology and restored muscle function (force production). Compared with BAG3 Met81 , BAG3 Ile81 displayed improved binding to the small heat shock protein (HspB8) in ischemic skeletal muscle cells and enhanced ischemic muscle autophagic flux. Conclusions: Taken together, our data demonstrate that genetic variation in BAG3 plays an important role in the prevention of ischemic tissue necrosis. These results highlight a pathway that preserves tissue survival and muscle function in the setting of ischemia.
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- 2017
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