Publications by authors named "Deborah Proctor"

Hexavalent chromium (CrVI) is known to cause lung cancer among workers exposed to high concentrations in certain historical industries. It is also a toxic air contaminant considered to pose a potentially significant cancer risk at comparatively low concentrations in urban air. However, very limited data currently exist to quantify risk at low-concentration occupational or environmental exposures.

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Electric arc furnace (EAF) slag is a coproduct of steel production used primarily for construction purposes. Some applications of EAF slag result in residential exposures by incidental ingestion and inhalation of airborne dust. To evaluate potential health risks, an EAF slag characterization program was conducted to measure concentrations of metals and leaching potential (including oral bioaccessibility) in 38 EAF slag samples.

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Background: Colonoscopy withdrawal time (CWT) of at least 6-9 minutes is the minimum time needed for adequate adenoma detection in the general population. The ideal CWT in patients with inflammatory bowel disease (IBD) has not been determined. We aimed to identify the optimal CWT associated with the detection of visible dysplasia in patients with IBD.

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Background: While there are multiple safe and effective agents for COVID-19 treatment, their impact in inflammatory bowel disease (IBD) remains uncertain.

Aims: Our objective was to assess the effects of these therapies on both IBD and COVID outcomes.

Methods: A single-center retrospective study of adult patients with IBD who contracted COVID-19 between 12/2020 and 11/2022 was performed.

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The toxicokinetics of manganese (Mn) are controlled through homeostasis because Mn is an essential element. However, at elevated doses, Mn is also neurotoxic and has been associated with respiratory, reproductive, and developmental effects. While health-based criteria have been developed for chronic inhalation exposure to ambient Mn, guidelines for short-term (24-h) environmental exposure are also needed.

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Objectives: Guidelines recommend performing a flexible sigmoidoscopy in patients hospitalized with acute severe ulcerative colitis (ASUC). However, it is unclear if time to sigmoidoscopy affects relevant clinical outcomes. We aimed to assess the impact of early sigmoidoscopy on clinical outcomes using a well-characterized cohort of patients with ASUC.

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Electric arc furnace (EAF) slag is a rock-like aggregate produced with carbon steel and used for construction, including residential ground cover. It is enriched with manganese (Mn) and other metals, including iron (Fe), but because metals are bound in mineral matrices, in vitro bioaccessibility (BA) is limited. We conducted a relative bioavailability (RBA) study using F344 rats to assess Mn RBA from EAF slag ingestion, compared with Mn in diet.

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Background: Inflammatory bowel disease (IBD) coexists in up to 80% of patients with primary sclerosing cholangitis (PSC). The aim of this study is to investigate the outcomes of immunomodulator (IMM)/advanced therapies for the treatment of PSC-IBD.

Methods: This was a single-center, retrospective study of patients with PSC from 1 January 2012 to 1 April 2021.

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Background: Combination therapy with thiopurines and anti-tumor necrosis factor (TNF) is superior to monotherapy in Crohn's disease (CD) and ulcerative colitis (UC). The optimal dose of thiopurines in combination therapy remains unclear. We investigated the impact of thiopurine dose in combination therapy on outcomes in inflammatory bowel disease (IBD).

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Background: Vedolizumab is used in inflammatory bowel disease (IBD), administered as a non-weight-based fixed dose. A higher body mass index (BMI) is associated with lower serum vedolizumab levels, but it is unclear whether it is associated with an unfavorable response to vedolizumab. We examined the relationship between BMI and the need for dose escalation, and the overall response to vedolizumab in IBD patients.

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Background: Despite being susceptible to vaccine-preventable diseases, patients with inflammatory bowel disease (IBD) have low vaccination rates. The aims of this study are to examine the rates of vaccine discussion and completion among patients of an IBD clinic that offers on-site vaccinations.

Methods: This is a retrospective study from March 1, 2019 to February 1, 2020 comparing vaccination discussion and completion rates for patients with IBD who visited 2 clinics-1 that offers on-site vaccination (Clinic A) and 1 that does not (Clinic B).

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Immune checkpoint inhibitors (ICIs) have transformed the management of advanced malignancies but are associated with diarrhea and colitis. The objective of our systematic review and meta-analysis was to determine the incidence and outcomes of ICI-associated diarrhea and colitis. Bibliographic databases were searched through August 13, 2019, for observational studies of ICI therapy reporting the incidence and/or treatment of diarrhea or colitis.

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Hexavalent chromium [Cr(VI)] exists in the ambient air at low concentrations (average upperbound ~0.1 ng/m) yet airborne concentrations typically exceed EPA's Regional Screening Level for residential exposure (0.012 ng/m) and other similar benchmarks, which assume a mutagenic mode of action (MOA) and use low-dose linear risk assessment models.

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The incidence and prevalence of Crohn's disease (CD) is rising globally. Patients with moderate to severe CD are at high risk for needing surgery and hospitalization and for developing disease-related complications, corticosteroid dependence, and serious infections. Optimal management of outpatients with moderate to severe luminal and/or fistulizing (including perianal) CD often requires the use of immunomodulator (thiopurines, methotrexate) and/or biologic therapies, including tumor necrosis factor-α antagonists, vedolizumab, or ustekinumab, either as monotherapy or in combination (with immunomodulators) to mitigate these risks.

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Inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease are chronic, relapsing and remitting disorders of intestinal inflammation with potential systemic manifestations. Despite the availability of current biologics, such as anti-tumor necrosis factor (anti-TNF), anti-integrins, anti-interleukins and small molecules such as tofacitinib, the rates of primary and secondary treatment failure remain high in IBD. This highlights the importance of continued development of new therapeutic targets and modifications of existing ones to improve the treatment response rates and to also improve the safety profile and tolerability of these medications.

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Background: There are limited data on how vedolizumab (VDZ) impacts extraintestinal manifestations (EIMs) in inflammatory bowel disease (IBD). The aim of this study was to determine the clinical outcomes of EIMs after initiation of VDZ for patients with IBD.

Methods: A multicenter retrospective study of patients with IBD who received at least 1 dose of VDZ between January 1, 2014 and August 1, 2019 was conducted.

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Small intestinal (SI) tumors are relatively uncommon outcomes in rodent cancer bioassays, and limited information regarding chemical-induced SI tumorigenesis has been reported in the published literature. Herein, we propose a cytotoxicity-mediated adverse outcome pathway (AOP) for SI tumors by leveraging extensive target species- and site-specific molecular, cellular, and histological mode of action (MOA) research for three reference chemicals, the fungicides captan and folpet and the transition metal hexavalent chromium (Cr(VI)). The gut barrier functions through highly efficient homeostatic regulation of SI epithelial cell sloughing, regenerative proliferation, and repair, which involves the replacement of up to 10 cells per day.

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