Virtual learning allows for adaptation of study strategies in a cohort of U.S. medical students

BACKGROUND

In response to the COVID-19 pandemic, most U.S. medical schools acutely transitioned from regimented in-person learning to highly flexible virtual asynchronous learning. This transition at our medical school provided a unique opportunity to evaluate if and how students adapted their academic and personal lives in response.

METHODS

Medical students in a single class that made this transition were retrospectively provided with 24-hour diaries for three periods - one shortly before the transition, a second early in the transition, and third several months into the transition - and asked to select the academic or personal activities done in each hour. The percentage of medical students performing each activity each hour was analyzed, as was the time spent on each activity per day, and per morning, afternoon, per evening within the day.

RESULTS

Overall study time did not change in either virtual period but shifted significantly to the morning (6 AM to 12 PM). Time spent studying in groups fell significantly during both virtual periods, concordant with a significant increase in alone study time in the early virtual period. Early in the transition to virtual learning, students replaced in-person didactics with online faculty lectures; several months later in virtual learning, they had replaced online faculty lectures with commercial products. There was no significant change in time spent on specific personal activities.

CONCLUSIONS

Consistent with extensive constraints imposed by the heavy cognitive load of a medical school curriculum, students did not significantly change their overall study time and any self-care-related activities in the transition to virtual learning. However, transitioning to virtual learning allowed our students to adapt their study strategies, i.e. reducing group study time and increasing lone studying time. Furthermore, students shifted studying time to the morning to optimize the management of the cognitive task-load they faced.

American Society for Pharmacology and Experimental Therapeutics Division for Pharmacology Education at EB2022-Meeting report

The American Society for Pharmacology and Experimental Therapeutics (ASPET) held its annual meeting at the Experimental Biology 2022 conference in Philadelphia, PA on April 2-5, 2022. The authors provide a synopsis and discussion of each of the four sessions presented at the meeting under the ASPET Division for Pharmacology Education (DPE).

Relationships between preadmission variables and academic outcomes for postbaccalaureate students in medical school

There is currently little guidance for medical school admissions committees regarding how to weigh postbaccalaureate program grades relative to undergraduate grades. This study was designed to address this issue. Admissions data, preclerkship course performance and United States Medical Licensing Exam (USMLE) Step 1 results were analyzed over three years for University of California, San Diego (UCSD) postbaccalaureate premedical (PBPM) students (n = 25), students who participated in other postbaccalaureate programs (n = 34), and for the remainder of the medical students who did not participate in any postbaccalaureate programs (n = 329). UCSD PBPM program alumni did not significantly differ in their cumulative academic performance on exams in preclerkship courses and USMLE Step 1 pass rates compared to the rest of the class despite their significantly lower GPA, lower Biology, Chemistry, Physics and Math (BCPM) GPA, and Medical College Admissions Test (MCAT) percentiles. For students who participated in the PBPM programs, PBPM program GPA was a significant predictor of preclerkship academic performance and USMLE Step 1 performance. When assessing academic readiness of applicants who have completed postbaccalaureate programs, admissions committees might closely consider the postbaccalaureate program GPA in addition to other academic metrices such as BCPM GPA and MCAT score.

A small‐group activity to enhance learning of cardiovascular drugs for health science students

This small‐group activity provides two cases in cardiovascular pharmacology to engage students in a medical or other health professions curriculum. The goal of this activity is to apply students' basic knowledge of physiology and pharmacology to clinical case scenarios. Students were provided with the cases 1 week in advance and were encouraged to use their lecture notes and/or other references of their choosing to answer as many of the questions as possible and prepare to discuss the answers with their classmates at the session. Facilitators were provided with detailed notes and a video that explain the answers and provide suggestions for engaging and challenging the students. For the 2021 academic year, 201 students (139 first‐year medical students and 62 second‐year pharmacy students) at UC San Diego participated in the small‐group activity. Eighteen facilitators were recruited to lead this 110‐min session. Students' performance was assessed on the final exam of their integrated cardiovascular physiology‐pharmacology course. Students achieved 84% (SD 17.54) on questions related to the small‐group session compared to 78% (SD 15.60) on other cardiovascular pharmacology questions not related to the activity. Student perceptions of the facilitators leading the small‐group activity were very positive (average of 4.7 on a 5‐point Likert Scale). Using this approach, we demonstrate that a small‐group activity with clinical scenarios helps students master the pharmacology content related to cardiovascular drugs. The small‐group activity included constructed response questions to foster conceptual understanding.

CRIg on liver macrophages clears pathobionts and protects against alcoholic liver disease

Complement receptor of immunoglobulin superfamily (CRIg) is expressed on liver macrophages and directly binds complement component C3b or Gram-positive bacteria to mediate phagocytosis. CRIg plays important roles in several immune-mediated diseases, but it is not clear how its pathogen recognition and phagocytic functions maintain homeostasis and prevent disease. We previously associated cytolysin-positive Enterococcus faecalis with severity of alcohol-related liver disease. Here, we demonstrate that CRIg is reduced in liver tissues from patients with alcohol-related liver disease. CRIg-deficient mice developed more severe ethanol-induced liver disease than wild-type mice; disease severity was reduced with loss of toll-like receptor 2. CRIg-deficient mice were less efficient than wild-type mice at clearing Gram-positive bacteria such as Enterococcus faecalis that had translocated from gut to liver. Administration of the soluble extracellular domain CRIg-Ig protein protected mice from ethanol-induced steatohepatitis. Our findings indicate that ethanol impairs hepatic clearance of translocated pathobionts, via decreased hepatic CRIg, which facilitates progression of liver disease.

The effect of sleep quality, sleep components, and environmental sleep factors on core curriculum exam scores among pharmacy students

INTRODUCTION

Sleep deprivation is associated with poor academic performance, although the impact on pharmacy students has been minimally reported. This study examined sleep quality in pharmacy students in the first (P1), second (P2), and third (P3) professional years during perceived low and high stress periods in a course. Individual sleep and environmental factors were also explored.

METHODS

This prospective cohort study used an 18-item survey adapted from the Pittsburgh Sleep Quality Index (PSQI) that included demographics, individual sleep components, and factors affecting sleep. Surveys were administered at the beginning of the quarter (low stress) and the week before final exams (high stress). Chi-square tests compared categorical variables; ANOVA/ANCOVA tests compared continuous variables.

RESULTS

During high stress, PSQI scores worsened among all classes and was significant for the P3s. Average sleep duration was 6.64 (SD 1.18) and 6.8 (SD 1.18) hours per night for P1s and P3s, respectively, at the beginning of the quarter; both groups had significant reduction in sleep duration at the end of the quarter. There were no significant correlations between PSQI and exam scores. Factors impacting sleep such as exercise, use of technology at bedtime, and work hours outside of school decreased during high times of stress, for P1s, P2s, and P3, respectively.

CONCLUSIONS

Students demonstrated worsening sleep quality during high stress periods and less sleep than recommended. Academic performance was not adversely affected. Future research should use sleep logs and other performance measures to determine the impact of sleep quality on academic success and wellbeing.

Bacteriophage targeting of gut bacterium attenuates alcoholic liver disease

Chronic liver disease due to alcohol use disorder contributes markedly to the global burden of disease and mortality^1–3. Alcoholic hepatitis is a severe and life-threatening form of alcohol-associated liver disease. The gut microbiota promotes ethanol-induced liver disease in mice⁴, but little is known about microbial factors responsible for this process. We identified cytolysin, a two-subunit exotoxin secreted by Enterococcus faecalis (E. faecalis)^5,6, to cause hepatocyte death and liver injury. Compared with controls, patients with alcoholic hepatitis have increased fecal numbers of E. faecalis. The presence of cytolysin-positive (cytolytic) E. faecalis correlated with liver disease severity and mortality in patients with alcoholic hepatitis. Using humanized mice colonized with bacteria from feces of patients with alcoholic hepatitis, we investigated the therapeutic effects of bacteriophages that target cytolytic E. faecalis. We found these phages to decrease cytolysin in the liver and abolish ethanol-induced liver disease in humanized mice. Our findings link cytolysin-positive E. faecalis with worse clinical outcomes and mortality in patients with alcoholic hepatitis. We show that bacteriophages can specifically target cytolytic E. faecalis, providing a method to precisely edit the intestinal microbiota. A prospective clinical trial with a larger cohort is required to validate human relevance of our findings and to test whether this new therapeutic approach is effective for patients with alcoholic hepatitis.

Assessing Students' Satisfaction with a Redesigned Pharmacology Course Series

Objective. To describe the revision of a pharmacology course series taught over three quarters within a Doctor of Pharmacy (PharmD) curriculum and assess changes in students' attitudes toward and performance after the revision. Methods. Based in part on students' dissatisfaction regarding a pharmacology course series, a course director was hired and tasked with teaching a major portion of the course content, rewriting course examinations, and facilitating active learning in the course series. Course evaluations and examination scores of students who completed the course series after the implementation of the redesigned curriculum (classes of 2015 and 2016) were assessed and compared with those of students who completed the course before the revisions were made (classes of 2013 and 2014). Results. Qualitative analysis of second-year pharmacy student evaluations identified a lack of integration and coordination within the pharmacology course sequence. Poor examination quality and the absence of active teaching methods were other frequently described shortcomings of the pharmacology curriculum. Course evaluations dramatically improved after shortcomings were addressed and students' performance in the subsequent therapeutics course also increased significantly. Conclusion. Adding additional structure to and oversight for a pharmacology course series by adding a course director improved student satisfaction with the course and improved performance in the subsequent therapeutics course. This study highlights the importance of a well-designed pharmacology curriculum for continued success in core courses in the PharmD curriculum.

YIPF6 controls sorting of FGF21 into COPII vesicles and promotes obesity

Fibroblast growth factor 21 (FGF21) is an endocrine hormone that regulates glucose, lipid, and energy homeostasis. While gene expression of FGF21 is regulated by the nuclear hormone receptor peroxisome proliferator-activated receptor alpha in the fasted state, little is known about the regulation of trafficking and secretion of FGF21. We show that mice with a mutation in the Yip1 domain family, member 6 gene (Klein-Zschocher [KLZ]; Yipf6KLZ/Y ) on a high-fat diet (HFD) have higher plasma levels of FGF21 than mice that do not carry this mutation (controls) and hepatocytes from Yipf6KLZ/Y mice secrete more FGF21 than hepatocytes from wild-type mice. Consequently, Yipf6KLZ/Y mice are resistant to HFD-induced features of the metabolic syndrome and have increased lipolysis, energy expenditure, and thermogenesis, with an increase in core body temperature. Yipf6KLZ/Y mice with hepatocyte-specific deletion of FGF21 were no longer protected from diet-induced obesity. We show that YIPF6 binds FGF21 in the endoplasmic reticulum to limit its secretion and specifies packaging of FGF21 into coat protein complex II (COPII) vesicles during development of obesity in mice. Levels of YIPF6 protein in human liver correlate with hepatic steatosis and correlate inversely with levels of FGF21 in serum from patients with nonalcoholic fatty liver disease (NAFLD). YIPF6 is therefore a newly identified regulator of FGF21 secretion during development of obesity and could be a target for treatment of obesity and NAFLD.

Dean's Perspective on Academic Communities at UC San Diego, School of Medicine

INTRODUCTION AND BACKGROUND

In 2010, the UC San Diego School of Medicine launched a new curriculum, the integrated scientific curriculum. As part of this curricular redesign, the school instituted academic communities. This perspective article outlines our experience with the first 8 years of these academic communities.

SINGLE-INSTITUTION EXPERIENCE

We initiated academic communities with the hope that this structure would cultivate enhanced student-student and student-faculty engagement, improve faculty-student mentoring, and create additional service-learning and student leadership opportunities. The communities would also provide an environment for small group learning throughout the 4-year curriculum. After 8 years of experience, a comparison of student survey data pre- and post establishment of academic communities demonstrated enhanced connectedness between students and faculty and higher scores for faculty mentoring and for career planning. Our own lived experience with the communities revealed several unanticipated outcomes. The community directors became a source of support and advice for one another. Some faculty and administrators whose previous roles were affected by start of the academic communities needed to adjust expectations.

CONCLUSIONS

The establishment of academic communities was associated with improvement in student-faculty engagement, student assessment of faculty mentoring, and career planning.

Benefit of focus group discussion beyond online survey in course evaluations by medical students in the United States: A qualitative study

In addition to online questionnaires, many medical schools use supplemental evaluation tools such as focus groups to evaluate their courses. Although some benefits of using focus groups in program evaluation have been described, it is unknown whether these in-person data collection methods provide sufficient additional information beyond online evaluations to justify them. In this study we analyze recommendations gathered from student evaluation team (SET) focus group meetings and analyzed whether these items were captured in open-ended comments within the online evaluations. Our results indicate that online evaluations captured only 49% of the recommendations identified via SETs. Surveys to course directors identified that 74% of the recommendations exclusively identified via the SETs were implemented within their courses. Our results indicate that SET meetings can provide information not easily captured in online evaluations and that these recommendations result in actual course changes.

A summer prematriculation program to help students succeed in medical school

Medical schools with a diverse student body face the challenge of ensuring that all students succeed academically. Many medical schools have implemented prematriculation programs to prepare students from diverse backgrounds; however, evidence on their impact is largely lacking. In this study, we analyzed participants' demographics as well as the impact of the prematriculation program on Year 1 performance. Predictive validity of the program was assessed and compared to other traditional predictors, including grade point average (GPA) and Medical College Admission Test (MCAT) scores and subscores. Linear mixed effect models determined the impact of the prematriculation program, and linear regression analysis assessed the predictive value of the overall score in the prematriculation program and other traditional predictors. Demographics of students participating in the prematriculation program from 2013 to 2015 (n = 75) revealed a significantly higher prevalence of academically disadvantaged students including older students, students with lower GPA and MCAT scores and students of racial and ethnic populations that are underrepresented in medicine, compared to non-participants (n = 293). Participants performed significantly better in Year 1 courses that were covered in the prematriculation program compared to courses that were not covered. The overall performance in the prematriculation program correlated significantly with Year 1 performance and was found to be a strong predictor for Year 1 performance. This study suggests that a prematriculation program can help students to succeed in the first year of medical school. The results have implications for medical schools seeking to implement or evaluate the effectiveness of their prematriculation program.

Dysregulation of serum bile acids and FGF19 in alcoholic hepatitis

BACKGROUND & AIMS

The degree of cholestasis is an important disease driver in alcoholic hepatitis, a severe clinical condition that needs new biomarkers and targeted therapies. We aimed to identify the largely unknown mechanisms and biomarkers linked to cholestasis in alcoholic hepatitis.

METHODS

Herein, we analyzed a well characterized cohort of patients with alcoholic hepatitis and correlated clinical and histological parameters and outcomes with serum bile acids and fibroblast growth factor 19 (FGF19), a major regulator of bile acid synthesis.

RESULTS

We found that total and conjugated bile acids were significantly increased in patients with alcoholic hepatitis compared with controls. Serum FGF19 levels were strongly increased and gene expression of FGF19 was induced in biliary epithelial cells and ductular cells of patients with alcoholic hepatitis. De novo bile acid synthesis (CYP7A1 gene expression and C4 serum levels) was significantly decreased in patients with alcoholic hepatitis. Importantly, total and conjugated bile acids correlated positively with FGF19 and with disease severity (model for end-stage liver disease score). FGF19 correlated best with conjugated cholic acid, and model for end-stage liver disease score best with taurine-conjugated chenodeoxycholic acid. Univariate analysis demonstrated significant associations between FGF19 and bilirubin as well as gamma glutamyl transferase, and negative correlations between FGF19 and fibrosis stage as well as polymorphonuclear leukocyte infiltration, in all patients with alcoholic hepatitis.

CONCLUSION

Serum FGF19 and bile acids are significantly increased in patients with alcoholic hepatitis, while de novo bile acid synthesis is suppressed. Modulation of bile acid metabolism or signaling could represent a promising target for treatment of alcoholic hepatitis in humans.

LAY SUMMARY

Understanding the underlying mechanisms that drive alcoholic hepatitis is important for the development of new biomarkers and targeted therapies. Herein, we describe a molecule that is increased in patients with alcoholic hepatitis. Modulating the molecular pathway of this molecule might lead to promising targets for the treatment of alcoholic hepatitis.

Small group activities within academic communities improve the connectedness of students and faculty

BACKGROUND

The University of California, San Diego, School of Medicine implemented a curriculum change that included reduction of lectures, incorporation of problem-based learning and other small group activities. Six academic communities were introduced for teaching longitudinal curricular content and organizing extracurricular activities.

METHODS

Surveys were collected from 904 first- and second-year medical students over 6 years. Student satisfaction data with their sense of connectedness and community support were collected before and after the implementation of the new curriculum. In a follow-up survey, medical students rated factors that contributed to their sense of connectedness with faculty and students (n = 134).

RESULTS

Students' perception of connectedness to faculty significantly increased following implementation of a curriculum change that included academic communities. Students ranked small group clinical skills activities within academic communities significantly higher than other activities concerning their sense of connectedness with faculty. Students' perception of connectedness among each other was high at baseline and did not significantly change. Small group activities scored higher than extracurricular activities regarding students' connectedness among themselves.

CONCLUSIONS

The implementation of a new curriculum with more small group educational activities including academic communities enhanced connectedness between students and faculty and resulted in an increased sense of community.

Gut-liver axis at the frontier of host-microbial interactions

Liver and intestine are tightly linked through the venous system of the portal circulation. Consequently, the liver is the primary recipient of gut-derived products, most prominently dietary nutrients and microbial components. It functions as a secondary "firewall" and protects the body from intestinal pathogens and other microbial products that have crossed the primary barrier of the intestinal tract. Disruption of the intestinal barrier enhances microbial exposure of the liver, which can have detrimental or beneficial effects in the organ depending on the specific circumstances. Conversely, the liver also exerts influence over intestinal microbial communities via secretion of bile acids and IgA antibodies. This mini-review highlights key findings and concepts in the area of host-microbial interactions as pertinent to the bilateral communication between liver and gut and highlights the concept of the gut-liver axis.

Effect of a Dedicated Pharmacy Student Summer Research Program on Publication Rate

Objectives. This study investigated the impact of an optional 12-week summer research program on the publication outcomes and satisfaction with the required research projects of doctor of pharmacy (PharmD) students at the Skaggs School of Pharmacy and Pharmaceutical Sciences (SSPPS) at the University of California San Diego. Methods. PubMed and Google searches provided student publications, and satisfaction surveys submitted by students provided their perceptions of the research project value. Results. Of the studied cohort, the 130 students who fulfilled the requirement through the optional summer research program provided 61 full-text manuscripts and 113 abstracts. The 305 students who chose the standard pathway provided 35 full-text manuscripts and 34 abstracts. Students in both pathways agreed or strongly agreed that the research project was a valuable experience. Conclusions. The 12-week intensive summer research program improved the publication rate of pharmacy students and provided a high overall satisfaction with this independent learning experience.

Student evaluation team focus groups increase students' satisfaction with the overall course evaluation process

CONTEXT

Most medical schools use online systems to gather student feedback on the quality of their educational programmes and services. Online data may be limiting, however, as the course directors cannot question the students about written comments, nor can students engage in mutual problem-solving dialogue with course directors. We describe the implementation of a student evaluation team (SET) process to permit course directors and students to gather shortly after courses end to engage in feedback and problem solving regarding the course and course elements.

METHODS

Approximately 16 students were randomly selected to participate in each SET meeting, along with the course director, academic deans and other faculty members involved in the design and delivery of the course. An objective expert facilitates the SET meetings. SETs are scheduled for each of the core courses and threads that occur within the first 2 years of medical school, resulting in approximately 29 SETs annually. SET-specific satisfaction surveys submitted by students (n = 76) and course directors (n = 16) in 2015 were used to evaluate the SET process itself. Survey data were collected from 885 students (2010-2015), which measured student satisfaction with the overall evaluation process before and after the implementation of SETs.

RESULTS

Students and course directors valued the SET process itself as a positive experience. Students felt that SETs allowed their voices to be heard, and that the SET increased the probability of suggested changes being implemented. Students' satisfaction with the overall evaluation process significantly improved after implementation of the SET process.

CONCLUSIONS

Our data suggest that the SET process is a valuable way to supplement online evaluation systems and to increase students' and faculty members' satisfaction with the evaluation process.

A designed TLR4/MD-2 complex to capture LPS

The family of Toll-like receptors (TLRs) is involved in the defense of an organism to microbial attack. TLR4-induced signaling is involved in infectious diseases, chronic inflammatory diseases and sepsis; therefore, we aimed at modulating TLR4-signaling via ligand-binding soluble receptors. Because recognition of microbial structures shows some species-specific traits, we specifically selected the mouse model for later in vivo studies. We first prepared the N-terminally Flag-tagged mouse (m) recombinant (r) soluble (s) fusion proteins mrsTLR4-IgGFc (T4Fc) and mrsMD-2 in Drosophila melanogaster Schneider 2 (S2) cells. The function of these molecules was tested by inhibition of synthesis of pro-inflammatory cytokines after stimulation of mouse macrophage RAW 264.7 cells with purified lipopolysaccharide (LPS). T4Fc alone had no inhibitory activity; however, a T4Fc/MD-2 complex blocked LPS activity. By analogy with `cytokine traps', we then prepared a designer molecule (LPS-Trap) by fusing MD-2 to the C-terminus of soluble TLR4 via a flexible linker. LPS-Trap significantly inhibited TNF production by LPS-stimulated RAW 264.7 cells. Thus, the T4Fc/MD-2 complex as well as the LPS-Trap blocked LPS activity in vitro and might thus represent a new therapeutic option in sepsis by neutralization of TLR4-activating ligands.

Writing on the board as students' preferred teaching modality in a physiology course

The introduction of PowerPoint presentation software has generated a paradigm shift in the delivery of lectures. PowerPoint has now almost entirely replaced chalkboard or whiteboard teaching at the undergraduate and graduate levels. This study investigated whether undergraduate biology students preferred to have lectures delivered by PowerPoint or written on the board as well as the reasons behind their preference. Two upper-division physiology courses were surveyed over a period of 7 yr. A total of 1,905 students (86.7%) indicated they preferred lectures delivered by "writing on the board" compared to 291 students (13.3%) who preferred PowerPoint. Common themes drawn from explanations reported by students in favor of writing on the board included: 1) more appropriate pace, 2) facilitation of note taking, and 3) greater alertness and attention. Common themes in favor of PowerPoint included 1) increased convenience, 2) focus on listening, and 3) more accurate and readable notes. Based on the students' very strong preference for writing on the board and the themes supporting that preference, we recommend that instructors incorporate elements of the writing on the board delivery style into whatever teaching modality is used. If instructors plan to use PowerPoint, the presentation should be paced, constructed, and delivered to provide the benefits of lectures written on the board. The advantages of writing on the board can be also incorporated into instruction intended to occur outside the classroom, such as animated narrated videos as part of the flipped classroom approach.

Deficiency of intestinal mucin-2 protects mice from diet-induced fatty liver disease and obesity

Nonalcoholic fatty liver disease (NAFLD) and obesity are characterized by altered gut microbiota, inflammation, and gut barrier dysfunction. Here, we investigated the role of mucin-2 (Muc2) as the major component of the intestinal mucus layer in the development of fatty liver disease and obesity. We studied experimental fatty liver disease and obesity induced by feeding wild-type and Muc2-knockout mice a high-fat diet (HFD) for 16 wk. Muc2 deficiency protected mice from HFD-induced fatty liver disease and obesity. Compared with wild-type mice, after a 16-wk HFD, Muc2-knockout mice exhibited better glucose homeostasis, reduced inflammation, and upregulated expression of genes involved in lipolysis and fatty acid β-oxidation in white adipose tissue. Compared with wild-type mice that were fed the HFD as well, Muc2-knockout mice also displayed higher intestinal and plasma levels of IL-22 and higher intestinal levels of the IL-22 target genes Reg3b and Reg3g. Our findings indicate that absence of the intestinal mucus layer activates the mucosal immune system. Higher IL-22 levels protect mice from diet-induced features of the metabolic syndrome.

Is intestinal inflammation linking dysbiosis to gut barrier dysfunction during liver disease?

Changes in the intestinal microbiota composition contribute to the pathogenesis of many disorders including gastrointestinal and liver diseases. Recent studies have broadened our understanding of the "gut-liver" axis. Dietary changes, other environmental and genetic factors can lead to alterations in the microbiota. Dysbiosis can further disrupt the integrity of the intestinal barrier leading to pathological bacterial translocation and the initiation of an inflammatory response in the liver. In this article, the authors dissect the different steps involved in disease pathogenesis to further refine approaches for the medical management of liver diseases. The authors will specifically discuss the role of dysbiosis in inducing intestinal inflammation and increasing intestinal permeability.

Linking membrane trafficking and intestinal homeostasis

A major challenge for the human body is to maintain symbiotic relationships with bacterial communities that colonize their intestines. Although several molecules important for intestinal homeostasis have been discovered, the vast array still needs to be identified. We approached this task using a forward genetic approach, which revealed several molecules essential for intestinal homeostasis. One recently identified molecule is Ypt1p-interacting protein 1 domain family, member 6 (Yipf6). Mice with a null mutation in Yipf6 are hypersensitive to dextran sulfate sodium (DSS) induced colitis and develop spontaneous intestinal inflammation. Members of the Yip1 family are believed to be involved in ER to Golgi membrane transport.

 

In this review we summarize recent advances in the understanding of genes involved in intestinal homeostasis with a specific focus on the Yip family members. We speculate on how deficiency or dysfunction of Yip molecules may dysregulate intestinal homeostasis leading to pathogenic states.

Deficiency of intestinal mucin-2 ameliorates experimental alcoholic liver disease in mice

The intestinal mucus layer protects the epithelium from noxious agents, viruses, and pathogenic bacteria present in the gastrointestinal tract. It is composed of mucins, predominantly mucin (Muc) 2, secreted by goblet cells of the intestine. Experimental alcoholic liver disease requires translocation of bacterial products across the intestinal barrier into the systemic circulation, which induces an inflammatory response in the liver and contributes to steatohepatitis. We investigated the roles of the intestinal mucus layer, and in particular Muc2, in development of experimental alcohol-associated liver disease in mice. We studied experimental alcohol-induced liver disease, induced by the Tsukamoto-French method (which involves continuous intragastric feeding of an isocaloric diet or alcohol) in wild-type and Muc2(-/-) mice. Muc2(-/-) mice showed less alcohol-induced liver injury and steatosis than developed in wild-type mice. Most notably, Muc2(-/-) mice had significantly lower plasma levels of lipopolysaccharide than wild-type mice after alcohol feeding. In contrast to wild-type mice, Muc2(-/-) mice were protected from alcohol-associated microbiome changes that are dependent on intestinal mucins. The antimicrobial proteins regenerating islet-derived 3 beta and gamma were expressed at significantly higher levels in the jejunum of Muc2(-/-) mice fed the isocaloric diet or alcohol compared with wild-type mice. Consequently, Muc2(-/-) mice showed increased killing of commensal bacteria and prevented intestinal bacterial overgrowth.

CONCLUSION

Muc2(-/-) mice are protected from intestinal bacterial overgrowth and dysbiosis in response to alcohol feeding. Subsequently, lower amounts of bacterial products such as endotoxin translocate into the systemic circulation, decreasing liver disease.

Creating diseases to understand what prevents them: genetic analysis of inflammation in the gastrointestinal tract

Inflammatory bowel diseases (IBD), including both ulcerative colitis and Crohn's disease, are extremely variable in severity and have strong genetic components. In mice, several mutations are known to favor or inhibit intestinal inflammation. But a comprehensive picture of the pathogenesis of IBD cannot be assembled based on the limited information so far available from mouse genetic analyses, nor can human IBD be stringently ascribed to mutations known to be influential in mice. This review highlights recent progress made using mouse models created through a forward genetic approach towards the understanding of genes that normally prevent intestinal inflammation.

ENU-induced phenovariance in mice: inferences from 587 mutations

Background

We present a compendium of N-ethyl-N-nitrosourea (ENU)-induced mouse mutations, identified in our laboratory over a period of 10 years either on the basis of phenotype or whole genome and/or whole exome sequencing, and archived in the Mutagenetix database. Our purpose is threefold: 1) to formally describe many point mutations, including those that were not previously disclosed in peer-reviewed publications; 2) to assess the characteristics of these mutations; and 3) to estimate the likelihood that a missense mutation induced by ENU will create a detectable phenotype.

Findings

In the context of an ENU mutagenesis program for C57BL/6J mice, a total of 185 phenotypes were tracked to mutations in 129 genes. In addition, 402 incidental mutations were identified and predicted to affect 390 genes. As previously reported, ENU shows strand asymmetry in its induction of mutations, particularly favoring T to A rather than A to T in the sense strand of coding regions and splice junctions. Some amino acid substitutions are far more likely to be damaging than others, and some are far more likely to be observed. Indeed, from among a total of 494 non-synonymous coding mutations, ENU was observed to create only 114 of the 182 possible amino acid substitutions that single base changes can achieve. Based on differences in overt null allele frequencies observed in phenotypic vs. non-phenotypic mutation sets, we infer that ENU-induced missense mutations create detectable phenotype only about 1 in 4.7 times. While the remaining mutations may not be functionally neutral, they are, on average, beneath the limits of detection of the phenotypic assays we applied.

Conclusions

Collectively, these mutations add to our understanding of the chemical specificity of ENU, the types of amino acid substitutions it creates, and its efficiency in causing phenovariance. Our data support the validity of computational algorithms for the prediction of damage caused by amino acid substitutions, and may lead to refined predictions as to whether specific amino acid changes are responsible for observed phenotypes. These data form the basis for closer in silico estimations of the number of genes mutated to a state of phenovariance by ENU within a population of G3 mice.

The Tpl2 mutation Sluggish impairs type I IFN production and increases susceptibility to group B streptococcal disease

Sluggish was identified in a population of third generation mice descended from N-ethyl-N-nitrosourea-mutagenized sires. Macrophages from homozygotes exhibited impaired TNF-alpha production in response to all TLR ligands tested and displayed impaired type I IFN production in response to TLR7 and TLR9 stimulations. The phenotype was confined to a critical region on mouse chromosome 18 and then ascribed to a T to A transversion in the acceptor splice site of intron 4 at position 13346 of the Map3k8 gene, resulting in defective splicing. The Map3k8(Sluggish) mutation does not result in susceptibility to viral infections, but Sluggish mice displayed high susceptibility to group B streptococcus infection, with impaired TNF-alpha and type I IFN production in infected macrophages. Our data demonstrate that the encoded protein kinase Tpl2 plays an essential role in cell signaling in the immune response to certain pathogens.

NOD2 regulates hematopoietic cell function during graft-versus-host disease

Nucleotide-binding oligomerization domain 2 (NOD2) polymorphisms are independent risk factors for Crohn's disease and graft-versus-host disease (GVHD). In Crohn's disease, the proinflammatory state resulting from NOD2 mutations have been associated with a loss of antibacterial function of enterocytes such as paneth cells. NOD2 has not been studied in experimental allogeneic bone marrow transplantation (allo-BMT). Using chimeric recipients with NOD2^−/− hematopoietic cells, we demonstrate that NOD2 deficiency in host hematopoietic cells exacerbates GVHD. We found that proliferation and activation of donor T cells was enhanced in NOD-deficient allo-BMT recipients, suggesting that NOD2 plays a role in the regulation of host antigen-presenting cells (APCs). Next, we used bone marrow chimeras in an experimental colitis model and observed again that NOD2 deficiency in the hematopoietic cells results in increased intestinal inflammation. We conclude that NOD2 regulates the development of GVHD through its inhibitory effect on host APC function.

MyD88 and Type I interferon receptor-mediated chemokine induction and monocyte recruitment during Listeria monocytogenes infection

Monocytes play a central role in defense against infection, but the mechanisms promoting monocyte recruitment and activation remain incompletely defined. Defense against Listeria monocytogenes, an intracellular bacterial pathogen, requires in vivo MCP-1 induction and CCR2-dependent recruitment of Ly6C(high) monocytes from bone marrow to sites of infection. Herein, we demonstrate that infection of bone marrow-derived macrophages with virulent L. monocytogenes induces MCP-1 expression in two phases. The first phase is rapid, induces low-level production of MCP-1, and is dependent on TLR/MyD88 signaling. The second phase promotes prolonged, higher level MCP-1 secretion and is dependent on signaling via the type I IFN receptor (IFNAR). Although attenuated L. monocytogenes strains that remain confined to the phagosome trigger TLR/MyD88-mediated signals and induce low-level MCP-1 expression, only cytosol-invasive bacteria promote IFNAR-dependent MCP-1 expression. In vivo, deficiency of either MyD88 or IFNAR signaling does not impair early monocyte emigration from bone marrow and recruitment to infected spleen. Loss of both MyD88 and IFNAR-mediated MCP-1 induction, however, results in deficient Ly6C(high) monocyte recruitment and increased susceptibility to L. monocytogenes infection. Our studies demonstrate that distinct but partially overlapping signal transduction pathways provide redundancy that ensures optimal monocyte recruitment to sites of microbial infection.

Mice with mutations of Dock7 have generalized hypopigmentation and white-spotting but show normal neurological function

The classical recessive coat color mutation misty (m) arose spontaneously on the DBA/J background and causes generalized hypopigmentation and localized white-spotting in mice, with a lack of pigment on the belly, tail tip, and paws. Here we describe moonlight (mnlt), a second hypopigmentation and white-spotting mutation identified on the C57BL/6J background, which yields a phenotypic copy of m/m coat color traits. We demonstrate that the 2 mutations are allelic. m/m and mnlt/mnlt phenotypes both result from mutations that truncate the dedicator of cytokinesis 7 protein (DOCK7), a widely expressed Rho family guanine nucleotide exchange factor. Although Dock7 is transcribed at high levels in the developing brain and has been implicated in both axon development and myelination by in vitro studies, we find no requirement for DOCK7 in neurobehavioral function in vivo. However, DOCK7 has non-redundant role(s) related to the distribution and function of dermal and follicular melanocytes.

Vancomycin-resistant enterococci exploit antibiotic-induced innate immune deficits

Infection with antibiotic-resistant bacteria, such as vancomycin-resistant Enterococcus (VRE), is a dangerous and costly complication of broad-spectrum antibiotic therapy. How antibiotic-mediated elimination of commensal bacteria promotes infection by antibiotic-resistant bacteria is a fertile area for speculation with few defined mechanisms. Here we demonstrate that antibiotic treatment of mice notably downregulates intestinal expression of RegIIIgamma (also known as Reg3g), a secreted C-type lectin that kills Gram-positive bacteria, including VRE. Downregulation of RegIIIgamma markedly decreases in vivo killing of VRE in the intestine of antibiotic-treated mice. Stimulation of intestinal Toll-like receptor 4 by oral administration of lipopolysaccharide re-induces RegIIIgamma, thereby boosting innate immune resistance of antibiotic-treated mice against VRE. Compromised mucosal innate immune defence, as induced by broad-spectrum antibiotic therapy, can be corrected by selectively stimulating mucosal epithelial Toll-like receptors, providing a potential therapeutic approach to reduce colonization and infection by antibiotic-resistant microbes.

Additive roles for MCP-1 and MCP-3 in CCR2-mediated recruitment of inflammatory monocytes during Listeria monocytogenes infection

Chemokine receptor-mediated recruitment of inflammatory cells is essential for innate immune defense against microbial infection. Recruitment of Ly6C(high) inflammatory monocytes from bone marrow to sites of microbial infection is dependent on CCR2, a chemokine receptor that responds to MCP-1 and MCP-3. Although CCR2(-/-) mice are markedly more susceptible to Listeria monocytogenes infection than are wild-type mice, MCP-1(-/-) mice have an intermediate phenotype, suggesting that other CCR2 ligands contribute to antimicrobial defense. Herein, we show that L. monocytogenes infection rapidly induces MCP-3 in tissue culture macrophages and in serum, spleen, liver, and kidney following in vivo infection. Only cytosol invasive L. monocytogenes induce MCP-3, suggesting that cytosolic innate immune detection mechanisms trigger chemokine production. MCP-3(-/-) mice clear bacteria less effectively from the spleen than do wild-type mice, a defect that correlates with diminished inflammatory monocyte recruitment. MCP-3(-/-) mice have significantly fewer Ly6C(high) monocytes in the spleen and bloodstream, and increased monocyte numbers in bone marrow. MCP-3(-/-) mice, like MCP-1(-/-) mice, have fewer TNF- and inducible NO synthase-producing dendritic cells (Tip-DCs) in the spleen following L. monocytogenes infection. Our data demonstrate that MCP-3 and MCP-1 provide parallel contributions to CCR2-mediated inflammatory monocyte recruitment and that both chemokines are required for optimal innate immune defense against L. monocytogenes infection.

MyD88-mediated signals induce the bactericidal lectin RegIII gamma and protect mice against intestinal Listeria monocytogenes infection

Listeria monocytogenes is a food-borne bacterial pathogen that causes systemic infection by traversing the intestinal mucosa. Although MyD88-mediated signals are essential for defense against systemic L. monocytogenes infection, the role of Toll-like receptor and MyD88 signaling in intestinal immunity against this pathogen has not been defined. We show that clearance of L. monocytogenes from the lumen of the distal small intestine is impaired in MyD88^−/− mice. The distal ileum of wild-type (wt) mice expresses high levels of RegIIIγ, which is a bactericidal lectin that is secreted into the bowel lumen, whereas RegIIIγ expression in MyD88^−/− mice is nearly undetectable. In vivo depletion of RegIIIγ from the small intestine of wt mice diminishes killing of luminal L. monocytogenes, whereas reconstitution of MyD88-deficient mice with recombinant RegIIIγ enhances intestinal bacterial clearance. Experiments with bone marrow chimeric mice reveal that MyD88-mediated signals in nonhematopoietic cells induce RegIIIγ expression in the small intestine, thereby enhancing bacterial killing. Our findings support a model of MyD88-mediated epithelial conditioning that protects the intestinal mucosa against bacterial invasion by inducing RegIIIγ.

MyD88-mediated signals induce in vivo production of the bactericidal lectin RegIIIγ and protect against intestinal Listeria monocytogenes infection (44.4)

Listeria monocytogenes (L. monocytogenes) is an intracellular bacterium that causes systemic infections after traversing the intestinal mucosa. To test the hypothesis that the Toll-like receptor pathway is involved in defense against intestinal L. monocytogenes infection, we analyzed the role of the common intracellular adaptor molecule myeloid differentiation primary-response protein 88 (MyD88) following oral infection with L. monocytogenes. We found that MyD88 deficient mice have increased susceptibility to intestinal L. monocytogenes infection with higher bacterial burden in spleen, liver, mesenteric lymph nodes, intestinal lumen, and small intestine (lamina propria and intestinal epithelium). Further in vitro and in vivo studies showed that MyD88 mediated protection primarily occurs in the distal small intestine. Recently, it was shown that the intestinal bactericidal lectin RegIIIγ has antibacterial activity against L. monocytogenes. RT-PCR and Western Blot analysis of distal small intestines showed that RegIIIγ is significantly diminished in MyD88 deficient mice. Since optimal expression of RegIIIγ requires MyD88-mediated signals, our findings suggest that increased susceptibility to intestinal L. monocytogenes infection in MyD88-deficient mice results from diminished levels of this bactericidal lectin in the distal small bowel.

A designed TLR4/MD-2 complex to capture LPS

The family of Toll-like receptors (TLRs) is involved in the defense of an organism to microbial attack. TLR4-induced signaling is involved in infectious diseases, chronic inflammatory diseases and sepsis; therefore, we aimed at modulating TLR4-signaling via ligand-binding soluble receptors. Because recognition of microbial structures shows some species-specific traits, we specifically selected the mouse model for later in vivo studies. We first prepared the N-terminally Flag-tagged mouse (m) recombinant (r) soluble (s) fusion proteins mrsTLR4-IgGFc (T4Fc) and mrsMD-2 in Drosophila melanogaster Schneider 2 (S2) cells. The function of these molecules was tested by inhibition of synthesis of pro-inflammatory cytokines after stimulation of mouse macrophage RAW 264.7 cells with purified lipopolysaccharide (LPS). T4Fc alone had no inhibitory activity; however, a T4Fc/MD-2 complex blocked LPS activity. By analogy with 'cytokine traps', we then prepared a designer molecule (LPS-Trap) by fusing MD-2 to the C-terminus of soluble TLR4 via a flexible linker. LPS-Trap significantly inhibited TNF production by LPS-stimulated RAW 264.7 cells. Thus, the T4Fc/MD-2 complex as well as the LPS-Trap blocked LPS activity in vitro and might thus represent a new therapeutic option in sepsis by neutralization of TLR4-activating ligands.

TLR-4 surface display on human monocytes is increased in septic patients

BACKGROUND

Sepsis is a serious condition, most often occurring as a complication of bacterial infections. The Toll-like receptors (TLR)-2 and TLR-4 have been identified as key molecules in response to Gram-positive and Gram-negative bacteria. This study aimed to assess possible alterations of the surface display of TLR-2 and TLR-4 on monocytes and granulocytes derived from patients with sepsis in comparison with healthy controls. -

METHODS

We have utilized flow-cytometry to determine the presence of TLR-2 and TLR-4 on the cell surface at baseline and in response to LPS (40 ng/ml) in vitro. -

RESULTS

We found no significant differences of TLR-2 display on monocytes and granulocytes from septic patients compared to controls. Surface display of TLR-4 on monocytes from septic patients at baseline was significantly higher than in healthy controls but there was no further response to LPS, whereas controls showed a significant increase of TLR-4 display on the cell surface after LPS stimulation. In contrast, TLR-4 baseline cell surface display on granulocytes was significantly lower in septic patients than in controls and there was no response to LPS in both groups. -

CONCLUSION

Our data suggest a complex relationship between TLR-4 display and bacterial challenge in vivo and in vitro.

Medication administration errors in adult patients in the ICU

OBJECTIVE

To quantify the incidence and specify the types of medication administration errors from a list of error-prone medications and to determine if patient harm resulted from these errors.

DESIGN

An observational evaluation.

SETTING

Five intensive care units (ICUs) in the United States.

PATIENTS AND PARTICIPANTS

Eight hundred fifty-one patients who were at least 18 years of age and admitted to surgical, medical or mixed ICUs during a 3 month period were included.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

A list of error-prone medications was adapted from the literature and evaluated for medication errors and patient harm. Of 5,744 observations in 851 patients, 187 (3.3%) medication administration errors were detected. the therapeutic classes most commonly associated with errors were vasoactive drugs 61 (32.6%) and sedative/analgesics 48 (25.7%). The most common type of error was wrong infusion rate with 71 (40.1%) errors. Twenty-one errors did not reach the patient and 159 reached the patient but did not result in harm, increased monitoring or intervention. Five errors required increased patient monitoring and two required intervention. None of the errors resulted in patient death.

CONCLUSIONS

This multicenter evaluation found fewer medication administration errors than the published literature, possibly due to the varying observational techniques and pharmacist involvement. Lorazepam and wrong infusion rates are associated with errors that occurred frequently, resulted in the greatest potential for harm and were common oversights in the system. These errors should be considered potential areas for betterment in the medication use process to improve patient safety.

A double-blind comparative study of doxazosin and nitrendipine in patients with mild-to-moderate essential hypertension

The antihypertensive efficacy and safety of doxazosin, a selective alpha 1-inhibitor, were compared with nitrendipine. Seventy-two hypertensive patients were entered into the 18-week, double-blind parallel group study, which involved three phases: a 4-week baseline period, a 10-week period in which patients received 1 to 8 mg of doxazosin or 10 and 20 mg of nitrendipine once daily, and a 4-week maintenance period. For all patients, the mean final daily doses were 2.5 mg for doxazosin and 13.9 mg for nitrendipine. In efficacy evaluable patients the percentages of therapy successes (standing diastolic blood pressure less than or equal to 90 mm Hg with greater than or equal to 5 mm Hg reduction or greater than or equal to 10 mm Hg decrease) were comparable for doxazosin (94%) and nitrendipine (91%), as was the proportion in whom blood pressure was "normalized" (standing diastolic blood pressure less than or equal to 90 mm Hg), 91% and 85, respectively. Blood pressures (diastolic and systolic in supine and standing positions) were significantly reduced (p less than 0.05) at all visits in both treatment groups. Ten patients (28%) in each treatment group experienced at least one adverse event. No clinically significant laboratory changes were apparent in either the doxazosin or nitrendipine groups, and no trends were observed with regard to organ systems or correlations with dose or duration of treatments. The investigators' global assessment of efficacy was rated excellent or good for all doxazosin-treated patients and excellent or good for 32 and fair for four in the nitrendipine group.(ABSTRACT TRUNCATED AT 250 WORDS)