Using artificial intelligence to promote equitable care for inpatients with language barriers and complex medical needs: clinical stakeholder perspectives.

OBJECTIVES: Inpatients with language barriers and complex medical needs suffer disparities in quality of care, safety, and health outcomes. Although in-person interpreters are particularly beneficial for these patients, they are underused. We plan to use machine learning predictive analytics to reliably identify patients with language barriers and complex medical needs to prioritize them for in-person interpreters. MATERIALS AND METHODS: This qualitative study used stakeholder engagement through semi-structured interviews to understand the perceived risks and benefits of artificial intelligence (AI) in this domain. Stakeholders included clinicians, interpreters, and personnel involved in caring for these patients or for organizing interpreters. Data were coded and analyzed using NVIVO software. RESULTS: We completed 49 interviews. Key perceived risks included concerns about transparency, accuracy, redundancy, privacy, perceived stigmatization among patients, alert fatigue, and supply-demand issues. Key perceived benefits included increased awareness of in-person interpreters, improved standard of care and prioritization for interpreter utilization; a streamlined process for accessing interpreters, empowered clinicians, and potential to overcome clinician bias. DISCUSSION: This is the first study that elicits stakeholder perspectives on the use of AI with the goal of improved clinical care for patients with language barriers. Perceived benefits and risks related to the use of AI in this domain, overlapped with known hazards and values of AI but some benefits were unique for addressing challenges with providing interpreter services to patients with language barriers. CONCLUSION: Artificial intelligence to identify and prioritize patients for interpreter services has the potential to improve standard of care and address healthcare disparities among patients with language barriers.

A framework for examining patient attitudes regarding applications of artificial intelligence in healthcare.

Background: While use of artificial intelligence (AI) in healthcare is increasing, little is known about how patients view healthcare AI. Characterizing patient attitudes and beliefs about healthcare AI and the factors that lead to these attitudes can help ensure patient values are in close alignment with the implementation of these new technologies. Methods: We conducted 15 focus groups with adult patients who had a recent primary care visit at a large academic health center. Using modified grounded theory, focus-group data was analyzed for themes related to the formation of attitudes and beliefs about healthcare AI. Results: When evaluating AI in healthcare, we found that patients draw on a variety of factors to contextualize these new technologies including previous experiences of illness, interactions with health systems and established health technologies, comfort with other information technology, and other personal experiences. We found that these experiences informed normative and cultural beliefs about the values and goals of healthcare technologies that patients applied when engaging with AI. The results of this study form the basis for a theoretical framework for understanding patient orientation to applications of AI in healthcare, highlighting a number of specific social, health, and technological experiences that will likely shape patient opinions about future healthcare AI applications. Conclusions: Understanding the basis of patient attitudes and beliefs about healthcare AI is a crucial first step in effective patient engagement and education. The theoretical framework we present provides a foundation for future studies examining patient opinions about applications of AI in healthcare.

Older Patients with Advanced Chronic Kidney Disease and Their Perspectives on Prognostic Information: a Qualitative Study.

BACKGROUND: Prognostic information is key to shared decision-making, particularly in life-limiting illness like advanced chronic kidney disease (CKD). OBJECTIVE: To understand the prognostic information preferences expressed by older patients with CKD. DESIGN AND PARTICIPANTS: Qualitative study of 28 consecutively enrolled patients over 65 years of age with non-dialysis dependent CKD stages 3b-5, receiving care in a multi-disciplinary CKD clinic. APPROACH: Semi-structured telephone or in-person interviews to explore patients' preference for and perceived value of individualized prognostic information. Interviews were analyzed using inductive content analysis. KEY RESULTS: We completed interviews with 28 patients (77.7 ± SD 6.8 years, 69% men). Patients varied in their preference for prognostic information and more were interested in their risk of progression to end-stage kidney disease (ESKD) than in life expectancy. Many conflated ESKD risk with risk of death, perceiving a binary choice between dialysis and quick decline and death. Patients expressed that prognostic information would allow them to plan, take care of important business, and think about their treatment options. Patients were accepting of prognostic uncertainty and imagined leveraging it to nurture hope or motivate them to better manage risk factors. They endorsed the desire to receive prognosis of life expectancy even though it may be hard to accept or difficult to talk about but worried it could create helplessness for other patients in their situation. CONCLUSION: Most, but not all, patients were interested in prognostic information and could see its value in motivating behavior change and allowing planning. Some patients expressed concern that information on life expectancy might cause depression and hopelessness. Therefore, prognostic information is most appropriate as part of a clinical conversation that fosters shared decision-making and helps patients consider treatment risks, benefits, and burdens in context of their lives.

Lay understandings of drug-gene interactions: The right medication, the right dose, at the right time, but what are the right words?

As pharmacogenomic (PGx) testing increases in popularity, lay concepts of drug-gene interactions set the stage for shared decision making in precision medicine. Few studies explore what recipients of PGx results think is happening in their bodies when a drug-gene interaction is discovered. To characterize biobank participants' understanding of PGx research results, we conducted a focus group study, which took place after PGx variants conferring increased risk of dihydropyrimidine dehydrogenase (DPD) deficiency were disclosed to biobank contributors. DPD deficiency confers an increased risk of adverse reaction to commonly used cancer chemotherapeutics. Ten focus groups were conducted, ranging from two to eight participants. Fifty-four individuals participated in focus groups. A framework approach was used for descriptive and explanatory analysis. Descriptive themes included participants' efforts to make sense of PGx findings as they related to: (1) health implications, (2) drugs, and (3) genetics. Explanatory analysis supplied a functional framework of how participant word choices can perform different purposes in PGx communication. Results bear three main implications for PGx research-related disclosure. First, participants' use of various terms suggest participants generally understanding their PGx results, including how positive PGx results differ from positive disease susceptibility genetic results. Second, PGx disclosure in biobanking can involve participant conflation of drug-gene interactions with allergies or other types of medical reactions. Third, the functional framework suggests a need to move beyond a deficit model of genetic literacy in PGx communication. Together, findings provide an initial evidence base for supporting bidirectional expert-recipient PGx results communication.

Provider Perspectives on Artificial Intelligence-Guided Screening for Low Ejection Fraction in Primary Care: Qualitative Study.

BACKGROUND: The promise of artificial intelligence (AI) to transform health care is threatened by a tangle of challenges that emerge as new AI tools are introduced into clinical practice. AI tools with high accuracy, especially those that detect asymptomatic cases, may be hindered by barriers to adoption. Understanding provider needs and concerns is critical to inform implementation strategies that improve provider buy-in and adoption of AI tools in medicine. OBJECTIVE: This study aimed to describe provider perspectives on the adoption of an AI-enabled screening tool in primary care to inform effective integration and sustained use. METHODS: A qualitative study was conducted between December 2019 and February 2020 as part of a pragmatic randomized controlled trial at a large academic medical center in the United States. In all, 29 primary care providers were purposively sampled using a positive deviance approach for participation in semistructured focus groups after their use of the AI tool in the randomized controlled trial was complete. Focus group data were analyzed using a grounded theory approach; iterative analysis was conducted to identify codes and themes, which were synthesized into findings. RESULTS: Our findings revealed that providers understood the purpose and functionality of the AI tool and saw potential value for more accurate and faster diagnoses. However, successful adoption into routine patient care requires the smooth integration of the tool with clinical decision-making and existing workflow to address provider needs and preferences during implementation. To fulfill the AI tool's promise of clinical value, providers identified areas for improvement including integration with clinical decision-making, cost-effectiveness and resource allocation, provider training, workflow integration, care pathway coordination, and provider-patient communication. CONCLUSIONS: The implementation of AI-enabled tools in medicine can benefit from sensitivity to the nuanced context of care and provider needs to enable the useful adoption of AI tools at the point of care. TRIAL REGISTRATION: ClinicalTrials.gov NCT04000087; https://clinicaltrials.gov/ct2/show/NCT04000087.

Cryo-EM structures of the ABCA4 importer reveal mechanisms underlying substrate binding and Stargardt disease.

ABCA4 is an ATP-binding cassette (ABC) transporter that flips N-retinylidene-phosphatidylethanolamine (N-Ret-PE) from the lumen to the cytoplasmic leaflet of photoreceptor membranes. Loss-of-function mutations cause Stargardt disease (STGD1), a macular dystrophy associated with severe vision loss. To define the mechanisms underlying substrate binding and STGD1, we determine the cryo-EM structure of ABCA4 in its substrate-free and bound states. The two structures are similar and delineate an elongated protein with the two transmembrane domains (TMD) forming an outward facing conformation, extended and twisted exocytoplasmic domains (ECD), and closely opposed nucleotide binding domains. N-Ret-PE is wedged between the two TMDs and a loop from ECD1 within the lumen leaflet consistent with a lateral access mechanism and is stabilized through hydrophobic and ionic interactions with residues from the TMDs and ECDs. Our studies provide a framework for further elucidating the molecular mechanism associated with lipid transport and disease and developing promising disease interventions.

Patient apprehensions about the use of artificial intelligence in healthcare.

While there is significant enthusiasm in the medical community about the use of artificial intelligence (AI) technologies in healthcare, few research studies have sought to assess patient perspectives on these technologies. We conducted 15 focus groups examining patient views of diverse applications of AI in healthcare. Our results indicate that patients have multiple concerns, including concerns related to the safety of AI, threats to patient choice, potential increases in healthcare costs, data-source bias, and data security. We also found that patient acceptance of AI is contingent on mitigating these possible harms. Our results highlight an array of patient concerns that may limit enthusiasm for applications of AI in healthcare. Proactively addressing these concerns is critical for the flourishing of ethical innovation and ensuring the long-term success of AI applications in healthcare.

"Who Doesn't Like Receiving Good News?" Perspectives of Individuals Who Received Genomic Screening Results by Mail.

As genomic sequencing expands to screen larger numbers of individuals, offering genetic counseling to everyone may not be possible. One approach to managing this limitation is for a genetic counselor to communicate clinically actionable results in person or by telephone, but report other results by mail. We employed this approach in a large genomic implementation study. In this paper, we describe participants' experiences receiving genomic screening results by mail. We conducted 50 semi-structured telephone interviews with individuals who received neutral genomic screening results by mail. Most participants were satisfied receiving neutral results by mail. Participants generally had a good understanding of results; however, a few participants had misunderstandings about their genomic screening results, including mistaken beliefs about their disease risk and the comprehensiveness of the test. No one reported plans to alter health behaviors, defer medical evaluations, or take other actions that might be considered medically problematic. Reporting neutral results by mail is unlikely to cause recipients distress or generate misunderstandings that may result in reduced vigilance in following recommended preventive health strategies. Nonetheless, some individuals may benefit from additional genetic counseling support to help situate their results in the context of personal concerns and illness experiences.

Communicating unexpected pharmacogenomic results to biobank contributors: A focus group study.

OBJECTIVES: The goals of this study were to explore 1) the impact of returning unexpected pharmacogenomic (PGx) results to biobank contributors, and 2) participant views about improving communication. METHODS: We conducted a qualitative focus group study with biobank participants (N = 54) who were notified by mail of an individual research result indicating increased risk for adverse events associated with the common cancer drug 5-fluorouracil (5-FU). We employed a framework approach for analysis. RESULTS: Our results revealed three themes illustrating participants' questions and uncertainty, especially regarding how to share results with health providers and family members, and remember them over time. Participants valued results for themselves and others, and for the future of medicine. Risk perception was framed by health identity. "Toxicity narratives," or familiarity with another's adverse reaction to chemotherapy, increased the sense of importance participants reported. CONCLUSION: These focus group results highlight research participant remaining questions and high valuation of PGx results, even when unexpected. PRACTICE IMPLICATIONS: We identify PGx research participants' needs for clear clinical translation messaging that attends to health identity, pragmatics of sharing information with family members, and patient perceptions of barriers to transferring research results to a clinical context.

Functional analysis and classification of homozygous and hypomorphic ABCA4 variants associated with Stargardt macular degeneration.

Stargardt macular degeneration (Stargardt disease 1 [STGD1]) is caused by mutations in the gene encoding ABCA4, an ATP-binding cassette protein that transports N-retinylidene-phosphatidylethanolamine (N-Ret-PE) across photoreceptor membranes. Reduced ABCA4 activity results in retinoid accumulation leading to photoreceptor degeneration. The disease onset and severity vary from severe loss in visual acuity in the first decade to mild visual impairment late in life. We determined the effect of 22 disease-causing missense mutations on the expression and ATPase activity of ABCA4 in the absence and presence of N-Ret-PE. Three classes were identified that correlated with the disease onset in homozygous STGD1 individuals: Class 1 exhibited reduced ABCA4 expression and ATPase activity that was not stimulated by N-Ret-PE; individuals homozygous for these variants had an early disease onset (≤13 years); Class 2 showed reduced ATPase activity with limited stimulation by N-Ret-PE; these correlated with moderate disease onset (14-40 years); and Class 3 displayed high expression and ATPase activity that was strongly activated by N-Ret-PE; these were associated with late disease onset (>40 years). On the basis of our results, we introduce a functionality index for gauging the effect of missense mutations on STGD1 severity. Our studies support the mild phenotype exhibited by the p.Gly863Ala, p.Asn1868Ile, and p.Gly863Ala/p.Asn1868Ile variants.

At a Moment's Notice: Community Advisory Board Perspectives on Biobank Communication to Supplement Broad Consent.

INTRODUCTION: To address ethical concerns about the of future research authorization, biobanks employing a broad model of consent can design ongoing communication with contributors. Notifying contributors at the time of sample distribution provides one form of communication to supplement broad consent. However, little is known about how community-informed governance might anticipate contributor responses and inform communication efforts. OBJECTIVE: We explored the attitudes of members of a three-site Community Advisory Board (CAB) network. CAB members responded to a hypothetical proposal for notifying biobank contributors at the time of sample distribution to researchers utilizing the biobank. METHODS: We used regularly scheduled CAB meetings to facilitate 3 large-group and 6 small-group discussions. Discussions were audio-recorded, transcribed, and analyzed for thematic content using descriptive thematic analysis. RESULTS: The results challenged our expectation of general support for the proposed communications. While CAB members identified some advantages, they were concerned about several potential harms to biobank contributors and the biobank. The CABs understood biobank communication in terms of an ongoing relationship with the biobank and a personal contribution to research. CONCLUSION: Our findings contribute to the emerging literature on community engagement in biobanking. Additional communication with biobank contributors can serve a variety of value-based objectives to supplement broad consent. Design of communication efforts by biobanks can be improved by CAB members' anticipation of the unintended consequences of additional contact with contributors. CAB members' holistic interpretation of communication efforts suggests that biobank leadership considers all communication options as part of a more comprehensive communications strategy.

Provincial development of a patient-reported outcome initiative to guide patient care, quality improvement, and research.

The BC Cancer Agency Radiotherapy (RT) program started the Prospective Outcomes and Support Initiative (POSI) at all six centres to utilize patient-reported outcomes for immediate clinical care, quality improvement, and research. Patient-reported outcomes were collected at time of computed tomography simulation via tablet and 2 to 4 weeks post-RT via either tablet or over the phone by a registered nurse. From 2013 to 2016, patients were approached on 20,150 attempts by POSI for patients treated with RT for bone metastases (52%), brain metastases (11%), lung cancer (17%), gynecological cancer (16%), head and neck cancer (2%), and other pilots (2%). The accrual rate for all encounters was 85% (n = 17,101), with the accrual rate varying between the lowest and the highest accruing centre from 78% to 89% ( P < .001) and varying by tumour site ( P < .001). Using the POSI database, we have performed research and quality improvement initiatives that have changed practice.

Identification of lanthanum-specific peptides for future recycling of rare earth elements from compact fluorescent lamps.

As components of electronic scrap, rare earth minerals are an interesting but little used source of raw materials that are highly important for the recycling industry. Currently, there exists no cost-efficient technology to separate rare earth minerals from an electronic scrap mixture. In this study, phage surface display has been used as a key method to develop peptides with high specificity for particular inorganic targets in electronic scrap. Lanthanum phosphate doped with cerium and terbium as part of the fluorescent phosphors of spent compact fluorescent lamps (CFL) was used as a target material of economic interest to test the suitability of the phage display method to the separation of rare earth minerals. One random pVIII phage library was screened for peptide sequences that bind specifically to the fluorescent phosphor LaPO4 :Ce3+ ,Tb3+ (LAP). The library contained at least 100 binding pVIII peptides per phage particle with a diversity of 1 × 109 different phage per library. After three rounds of enrichment, a phage clone containing the surface peptide loop RCQYPLCS was found to bind specifically to LAP. Specificity and affinity of the identified phage bound peptide was confirmed by using binding and competition assays, immunofluorescence assays, and zeta potential measurements. Binding and immunofluorescence assays identified the peptide's affinity for the fluorescent phosphor components CAT (CeMgAl11 O19 :Tb3+ ) and BAM (BaMgAl10 O17 :Eu2+ ). No affinity was found for other fluorescent phosphor components such as YOX (Y2 O3 :Eu3+ ). The binding specificity of the RCQYPLCS peptide loop was improved 3-51-fold by using alanine scanning mutagenesis. The identification of peptides with high specificity and affinity for special components in the fluorescent phosphor in CFLs provides a potentially new strategic approach to rare earth recycling. Biotechnol. Bioeng. 2017;114: 1016-1024. © 2016 Wiley Periodicals, Inc.

Identification of mineral-binding peptides that discriminate between chalcopyrite and enargite.

Innovative approaches to the separation of minerals and subsequent extraction of metals are imperative owing to the increasing mineralogical complexity of ore deposits that are difficult or even impossible to separate into slurries or solutions containing only the minerals or metals of interest. Low recovery of metal is typical for these complex deposits leading to significant losses to tailings. In addition, the minerals often contain impurities, some toxic, which are difficult and costly to control or manage during the processing of a concentrate or other mineral product. One example of this complex situation is the significant economic and environmental costs associated with diluting and processing copper concentrates containing arsenic (in the form of the mineral enargite, Cu3 AsS4 ) in the production of pure copper. To overcome these separation problems, we have utilized phage display to identify peptides that demonstrate selective recognition of enargite and the arsenic-free copper sulfide, chalcopyrite. Screening of two random peptide phage display libraries resulted in the identification of an enargite-selective peptide with the sequence MHKPTVHIKGPT and a chalcopyrite-selective peptide with the sequence RKKKCKGNCCYTPQ. Mineral-binding selectivity was demonstrated by binding studies, zeta potential determination and immunochemistry. Peptides that have the ability to discriminate between enargite and chalcopyrite provide a greener option for the separation of arsenic containing contaminants from copper concentrates. This represents the first step towards a major advance in the replacement or reduction of toxic collectors as well as reducing the level of arsenic-bearing minerals in the early stages of mineral processing. Biotechnol. Bioeng. 2017;114: 998-1005. © 2016 Wiley Periodicals, Inc.

Comparison of patient-reported outcomes with single versus multiple fraction palliative radiotherapy for bone metastasis in a population-based cohort.

BACKGROUND: Despite randomized control trials showing equivalent efficacy between single-fraction (SF) and multiple-fraction (MF) radiation therapy (RT) for bone metastases (BoM), considerable variation in fractionation exists. We compared patient-reported outcomes (PROs) following SF versus MF RT in a population-based cohort. METHODS: PROs were chosen to assess patients' perception of pain, function, and symptom frustration. Total score was the sum of the 3 questions. RESULTS: 968 patients completed pre and post-RT PROs, 35% (335) had complicated BoM. Overall, there were no differences in total score improvement (79% vs. 83%; p=0.13), nor for complicated BoM (77% vs. 84%; p=0.12), SFRT and MFRT respectively. On multivariate analysis no differences in improvement in total score were observed between SFRT and MFRT overall (OR=0.71; 95% CI 0.49-1.02; p=0.06), nor for complicated BoM (OR=0.74; 95% CI 0.39-1.39; p=0.35). In the complicated BoM subset, pain complete response (CR) (19% vs. 33%; p=0.01) and functional improvement occurred more commonly in the MFRT group (69% vs. 81%; p=0.04). CONCLUSION: Improvements in PROs for pain, function and symptom frustration were similar between SFRT and MFRT supporting the use of hypofractionated regimens. Using a simple, 3-question, telephone-based questionnaire to assess response to palliative RT is a feasible strategy to collect PROs.

Bacteriophage-induced aggregation of oil sands tailings.

Very large quantities of tailings are produced as a result of processing oil sands. After the sand particles settle out, a dense stable mixture of clay, silt, water with residual bitumen, salts, and organics called mature fine tailings (MFT) can remain in suspension for decades. Research into developing methods that would allow consolidation and sedimentation of the suspended particles is ongoing. We have studied the ability of a filamentous bacteriophage (called VP12 bearing the peptide DSQKTNPS at the N-terminus of the major coat protein pVIII) to aggregate MFT. To understand the biophysical basis of the aggregation, phage-induced aggregation of diluted MFT was measured at room temperature under varying conditions of pH, salt, detergent. Phage at concentrations of 5.0 × 10(11)/mL to 10(12)/mL induced rapid settling of the diluted MFT. The addition of sodium chloride (10 mM) lowered the concentration of phage required to induce aggregation. Since the non-ionic detergents Triton-X 100 and Tween-20, and the ionic detergent sodium deoxycholate had little effect, hydrophobic interactions do not appear to be a major contributor to the phage-induced aggregation of MFT. However, aggregation was prevented at pH values higher than 9.0 suggesting that positively charged amino acid residues are required for MFT aggregation by phage. Genetic engineering of the pVIII peptide sequence indicated that hydrogen bonding also contributes to phage-induced aggregation. In addition, replacing the basic residue lysine with an alanine in the recombinant peptide of VP12 completely prevented phage-induced aggregation. Three other phage displaying different amino acid sequences but all containing a lysine in the same position had variable aggregation efficiencies, ranging from no aggregation to rapid aggregation. We conclude that not only are the functional groups of the amino acids important, but the conformation that is adopted by the variable pVIII peptide is also important for phage-induced MFT aggregation.

Optimization of fermentation parameters in phage production using response surface methodology.

Previously, we used computer-controlled fermentation technology to improve the yield of filamentous phage produced in Escherichia coli by 10-fold (Grieco et al., Bioprocess Biosyst Eng 32:773-779, 2009). In the current study, three major fermentation parameters (temperature, dissolved oxygen [DO], and pH) were investigated using design of experiments (DOE) methodology. Response surface methodology (RSM) was employed to create a process model and determine the optimal conditions for maximal phage production. The experimental data fitted best to a quadratic model (p < 0.0001). Temperature and pH, but not DO, proved to be significant variables. The model predicted a theoretical optimal condition for maximal bacteriophage production at temperature of 28.1 °C and pH 6.9. A validation run resulted in phage production [3.49 × 10(11) transducing units (TU)/mL] comparable to the predicted value (2.86 × 10(11) TU/mL). This represented a 7-fold increase in phage production above that obtained without optimization, resulting in a 70-fold increase above that achieved by shake flask culture alone.

Effects of bacteriophage on the surface properties of chalcopyrite (CuFeS2), and phage-induced flocculation of chalcopyrite, glacial till, and oil sands tailings.

The binding of mineral-specific phage to the surface of chalcopyrite (CuFeS(2)) was investigated by using X-ray photoelectron spectroscopy and scanning Auger microscopy. These studies confirmed the elemental composition of the minerals and confirmed that bacteriophage were bound to the mineral surface. These techniques also revealed that the phage were not forming a continuous film over the entire surface of the CuFeS(2) particles, but selectively bound to the slimes coating the particles. In addition, the effect of mineral-specific phage binding to the surface of CuFeS(2) was investigated using induction time and zeta potential measurements. Bacteriophage (10(12) /mL) increased the induction time (contact time resulting in 50% particle attachment to a bubble) from ∼7.5 to ∼17 ms and reversed the zeta potential from negative to positive. In the course of performing the zeta potential measurements on particles <45 µm in diameter, phage-induced aggregation was observed. The mechanism of aggregation was explored using a range of pH (3-11) and cation concentrations. Aggregation was observed across the tested pH range and with all cations. Phage also mediated aggregation of glacial till and oil sands tailings in a dose-dependent and particle size-dependent manner. We conclude that binding of bacteriophage to the surface of CuFeS(2) does alter its surface properties.

Human hephaestin expression is not limited to enterocytes of the gastrointestinal tract but is also found in the antrum, the enteric nervous system, and pancreatic {beta}-cells.

Hephaestin (Hp) is a membrane protein with ferroxidase activity that converts Fe(II) to Fe(III) during the absorption of nutritional iron in the gut. Using anti-peptide antibodies to predicted immunogenic regions of rodent Hp, previous immunocytochemical studies in rat, mouse, and human gut tissues localized Hp to the basolateral membranes of the duodenal enterocytes where the Hp was predicted to aid in the transfer of Fe(III) to transferrin in the blood. We used a recombinant soluble form of human Hp to obtain a high-titer polyclonal antibody to Hp. This antibody was used to identify the intracellular location of Hp in human gut tissue. Our immunocytochemical studies confirmed the previous localization of Hp in human enterocytes. However, we also localized Hp to the entire length of the gastrointestinal tract, the antral portion of the stomach, and to the enteric nervous system (both the myenteric and submucous plexi). Hp was also localized to human pancreatic beta-cells. In addition to its expression in the same cells as Hp, ferroportin was also localized to the ductal cells of the exocrine pancreas. The localization of the ferroxidase Hp to the neuronal plexi and the pancreatic beta cells suggests a role for the enzymatic function of Hp in the protection of these specialized cell types from oxidative damage.