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1.
Discov Educ ; 1(1): 22, 2022.
Article in English | MEDLINE | ID: mdl-36590921

ABSTRACT

One promising practice for increasing active learning in undergraduate science education is the use of a mentoring network. The Promoting Active Learning and Mentoring (PALM) Network was launched with practitioners from several professional societies and disciplines to make changes in their teaching based on evidence-based practices and to encourage the members to reflect deeply on their teaching experiences. Members of the Network interviewed seven previous Fellows, 1 to 6 years after completing their fellowship, to better understand the value of the Network and how these interactions impacted their ability to sustain change toward more active teaching practices. The interviews resulted in the creation of three personas that reflect the kinds of educators who engaged with the Network: Neil the Novice, Issa the Isolated, and Etta the Expert. Key themes emerged from the interviews about how interactions with the PALM Network sustained change toward evidence-based teaching practices allowing the members to readily adapt to the online learning environment during the COVID-19 pandemic. Understanding how the personas intersect with the ADKAR model contributes to a better understanding of how mentoring networks facilitate transformative change toward active learning and can inform additional professional development programs. Supplementary Information: The online version contains supplementary material available at 10.1007/s44217-022-00023-w.

2.
Insects ; 12(12)2021 Dec 18.
Article in English | MEDLINE | ID: mdl-34940224

ABSTRACT

Studies of tickborne illness have benefited from interactions between scientists and community members. Most participants in community science projects are well-educated adults, but there are anticipated benefits from engaging younger students in research. We evaluated whether an outreach experience for rural middle-school students promoted student interest in science and resulted in the generation of samples that could be used for tick testing to assess disease risk. Middle-school students from 78 Wisconsin communities developed interdisciplinary hypotheses about the spread of Lyme disease, identified ticks, and extracted DNA from ticks to assess the prevalence of pathogens Borrelia burgdorferi, Anaplasma phagocytophillium, and Babesia microti. As a result of this intervention, students were able to successfully complete the research protocol and explain the rationale for completing the experiment. Of student participants, 84.7% reported no difficulty completing the protocol, 66% of the student samples gave reliable PCR results, and 76% of students reported interest in participating in similar experiments. Our study shows that tick outreach programs that incorporate community-based science promote knowledge about Lyme disease, facilitate engagement between students and scientists, and generate samples that can be successfully utilized for pathogen testing.

3.
WMJ ; 120(3): 188-194, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34710299

ABSTRACT

INTRODUCTION: Medical student burnout has received increasing attention in recent years due to greater acceptance of psychological and emotional vulnerability in the health care profession. Given the significant investment of personal and financial resources in this demanding profession, continued evaluation of factors contributing to burnout in medical training is necessary. A midwestern medical college with a longstanding 4-year medical degree program created 2 regional campuses that utilize a calendar-efficient 3-year medical degree program. The objective in this study is to examine if medical student burnout scores are higher for students on the 3-year campuses and how that is affected by emotional intelligence. METHODS: First- and second-year medical students voluntarily completed the Maslach Burnout Inventory for Students (scale: 1 = never, 7 = every day) and the Trait Emotional Intelligence Questionnaire (scale: 1 = completely disagree, 7 = completely agree). Multifactor analysis of variance assessed mean differences in burnout between campus and gender. Multivariate linear regressions were used for predicting burnout from emotional intelligence. RESULTS: Three-year campus students reported significantly (P<0.010) higher mean [SD] scores (8.3 [2.0]) than the 4-year campus students (7.4 [2.4]), and female students reported significantly (P<0.049) higher scores (8.2 [2.0]) than male students (7.6 [2.4]). Five emotional intelligence facets were independently associated with increased burnout scores (R² = 0.26, P<0.001) but significantly varied with campus and gender. CONCLUSIONS: There were higher burnout scores in students studying on the two 3-year campuses compared to students on the traditional 4-year campus and higher scores for female students than male students. Different facets of emotional intelligence mitigated student burnout by campus and gender.


Subject(s)
Burnout, Professional , Students, Medical , Burnout, Professional/epidemiology , Burnout, Psychological , Emotional Intelligence , Female , Humans , Male , Surveys and Questionnaires
4.
BMC Med Educ ; 19(1): 417, 2019 Nov 11.
Article in English | MEDLINE | ID: mdl-31711472

ABSTRACT

BACKGROUND: Medical student learning experiences should facilitate progressive development of competencies required for practice. Medical school training opportunities have traditionally focused on acquiring medical knowledge and patient care competencies while affording less opportunity to receive feedback on practice-based improvement and system-based practice competencies. The Prematriculation program at the University of Minnesota Medical School Duluth Campus (UM MSD) utilized near-peer mentors to support the transition of students underrepresented in medicine, including American Indian/ Alaska Natives (AI/AN) and those from rural backgrounds, into medical school. The purpose of this study is to better define the role of near-peer mentors and explore the alignment of near-peer mentorship with the ACGME core competencies. METHODS: An important component of the Prematriculation program, designed to prepare incoming under-represented students for medical school, was the inclusion of near-peer mentors. The six near-peer mentors participated in semi-structured interviews or focus groups within 1 year of serving as a near-peer mentor. Themes emerged from open-coding of the transcripts. RESULTS: The near-peer mentors drew on their own experiences to transmit information that supported the socialization of the matriculating students into medical school. Direct benefits to the mentors included solidifying their own understanding of medical knowledge and execution of procedural skills. Mentors provided examples of benefits related to their own development of interpersonal communication and professionalism skills. Operating in the context of the program provided opportunities to engage mentors in practice-based improvement and system-based practice. CONCLUSIONS: Serving as a near-peer mentor offers significant benefits to medical students from backgrounds underrepresented in medicine. By taking on the peer mentoring leadership role, students progressed toward the competencies required of an effective physician. Given the importance of acquiring these competencies, it is worth considering how near-peer mentoring can be applied more broadly across the medical school curriculum.


Subject(s)
Clinical Competence , Education, Medical , Mentors , Minority Groups/education , Peer Group , Students, Medical/psychology , Education, Medical/methods , Female , Humans , Indians, North American , Male , Minnesota , Minority Groups/psychology , Professional Role/psychology
5.
CBE Life Sci Educ ; 17(1)2018.
Article in English | MEDLINE | ID: mdl-29378751

ABSTRACT

Scientists and educators travel great distances, spend significant time, and dedicate substantial financial resources to present at conferences. This highlights the value placed on conference interactions. Despite the importance of conferences, very little has been studied about what is learned from the presentations and how presenters can effectively achieve their goals. This essay identifies several challenges presenters face when giving conference presentations and discusses how presenters can use the tenets of scientific teaching to meet these challenges. We ask presenters the following questions: How do you engage the audience and promote learning during a presentation? How do you create an environment that is inclusive for all in attendance? How do you gather feedback from the professional community that will help to further advance your research? These questions target three broad goals that stem from the scientific teaching framework and that we propose are of great importance at conferences: learning, equity, and improvement. Using a backward design approach, we discuss how the lens of scientific teaching and the use of specific active-learning strategies can enhance presentations, improve their utility, and ensure that a presentation is broadly accessible to all audience members.


Subject(s)
Congresses as Topic , Learning , Science/education , Feedback , Goals , Humans , Problem-Based Learning
6.
Fam Med ; 49(5): 388-393, 2017 May.
Article in English | MEDLINE | ID: mdl-28535321

ABSTRACT

BACKGROUND AND OBJECTIVES: The University of Minnesota Medical School Duluth (MSD) opened in 1972 with a mission to train physicians serving rural Minnesota, emphasizing family medicine and American Indian (AI) communities. Nationwide there are shortages in family medicine and AI physicians, and MSD is a leader in these outcomes. METHODS: This is a longitudinal, retrospective cohort analysis of 1972-2009 MSD graduates using descriptive statistics and multivariate regression to determine relationships between gender, race, age, and hometown and outcomes of family medicine specialty, rural practice, and rural family medicine practice. RESULTS: MSD graduate outcomes are significantly higher than other US medical schools but declining, 47% chose family medicine and 37% chose a rural first practice location. Selection of rural and family medicine declined more rapidly for men than women, but there was no overall gender difference. AI graduates had rates of rural family medicine similar to their white classmates and older AI students were more likely to select rural family medicine. Graduates from rural hometowns were more likely to select rural practice but not to practice family medicine. CONCLUSIONS: MSD culture and curricula produce AI, family medicine, and rural physicians, but the school is experiencing a downward trend. Understanding the relationship between demographics and outcomes over time will assist policy makers and educators in optimizing strategies to develop the rural family medicine workforce.


Subject(s)
Family Practice , Medically Underserved Area , Physicians, Family/statistics & numerical data , Professional Practice Location/statistics & numerical data , Rural Health Services , Adult , Career Choice , Education, Medical, Graduate , Female , Humans , Indians, North American/statistics & numerical data , Longitudinal Studies , Male , Minnesota , Retrospective Studies , Workforce
7.
Acad Med ; 92(5): 641-648, 2017 05.
Article in English | MEDLINE | ID: mdl-28441674

ABSTRACT

Indigenous populations experience dramatic health disparities; yet, few medical schools equip students with the skills to address these inequities. At the University of Minnesota Medical School, Duluth campus, a project to develop an Indigenous health curriculum began in September 2013. This project used collaborative and decolonizing methods to gather ideas and opinions from multiple stakeholders, including students, community members, faculty, and administration, to guide the process of adding Indigenous health content to the curriculum to prepare students to work effectively with Indigenous populations. A mixed-methods needs assessment was implemented to inform the instructional design of the curriculum. In June 2014, stakeholders were invited to attend a retreat and complete a survey to understand their opinions of what should be included in the curriculum and in what way. Retreat feedback and survey responses indicated that the most important topics to include were cultural humility, Indigenous culture, social/political/economic determinants of health, and successful tribal health interventions. Stakeholders also emphasized that this content should be taught by tribal members, medical school faculty, and faculty in complementary departments (e.g., American Indian Studies, Education, Social Work) in a way that incorporates experiential learning.Preliminary outcomes include the addition of a seven-hour block of Indigenous content for first-year students taught primarily by Indigenous faculty from several departments. To address the systemic barriers to health and well-being and provider bias that Indigenous patients experience, this project sought to gather data and opinions regarding the training of medical students through a process of Indigenizing research and education.


Subject(s)
Curriculum , Education, Medical, Undergraduate , Health Status Disparities , Indians, North American , Attitude of Health Personnel , Faculty, Medical , Health Services, Indigenous , Humans , Minnesota , Qualitative Research , Students, Medical
8.
Med Educ Online ; 22(1): 1272835, 2017.
Article in English | MEDLINE | ID: mdl-28178916

ABSTRACT

BACKGROUND AND OBJECTIVES: A four-week interdisciplinary pre-matriculation program for Native American and rural medical students was created and its impact on students' transition to medical school was assessed. The program extends the goals of many pre-matriculation programs by aiming to increase not only students' understanding of basic science knowledge, but also to build student self-efficacy through practice with medical school curricular elements while developing their academic support networks. DESIGN: A mixed method evaluation was used to determine whether the goals of the program were achieved (n = 22). Student knowledge gains and retention of the microbiology content were assessed using a microbiology concept inventory. Students participated in focus groups to identify the benefits of participating in the program as well as the key components of the program that benefitted the students. RESULTS: Program participants showed retention of microbiology content and increased confidence about the overall medical school experience after participating in the summer program. CONCLUSIONS: By nurturing self-efficacy, participation in a pre-matriculation program supported medical students from Native American and rural backgrounds during their transition to medical school. ABBREVIATIONS: CAIMH: Center of American Indian and Minority Health; MCAT: Medical College Admission Test; PBL: Problem based learning; UM MSD: University of Minnesota Medical School Duluth.


Subject(s)
Education, Medical, Undergraduate/organization & administration , Health Knowledge, Attitudes, Practice , Minority Groups/psychology , Rural Population , Self Efficacy , Adult , Education, Medical, Undergraduate/standards , Female , Focus Groups , Humans , Interdisciplinary Studies , Male , Program Evaluation , Rural Health Services/organization & administration , United States , United States Indian Health Service/organization & administration , Young Adult
9.
CBE Life Sci Educ ; 15(3)2016.
Article in English | MEDLINE | ID: mdl-27521233

ABSTRACT

With the primary objective of attracting and retaining students from underrepresented backgrounds in the sciences, evaluation of one institution's program has been ongoing over the past three years. Interviews with mentors in the program followed by focus groups conducted with mentees reveal key factors that shape undergraduate students' research experiences. In the present study, attention is given to data gathered from 15 mentees in the program, the majority of whom have enrolled in community colleges, represent low socioeconomic backgrounds, and are nontraditional students. The results from focus groups with the mentees provide information on the benefits of participating in the program, characteristics of good mentors, challenges to the mentoring relationship, and the effects of underrepresented status on pursuit of advanced degrees. Comparisons of mentees' comments about the mentoring relationship with mentors' comments reveal similar themes and patterns while also demonstrating interesting differences. The qualitative findings are also juxtaposed with participants' responses on the Survey of Undergraduate Research Experiences. Taken together, the data enhance our understanding of the experiences of underrepresented students in faculty-mentored research programs and highlight challenges and perspectives of students who are transferring to the university from a community college.


Subject(s)
Mentoring , Minority Groups/education , Science/education , Students , Adult , Female , Humans , Male , Mentors , Young Adult
10.
J Microbiol Biol Educ ; 17(1): 63-9, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27047593

ABSTRACT

The goal of this project is to promote Lyme disease prevention and to cultivate an interest in science through a citizen-science project coordinated by researchers at a public university and teachers at rural high schools. The lesson plan is designed to increase student interest in pursuing a science career through participation in an authentic research experience, utilizing a topic that has implications on the health of the surrounding community. Students are introduced in the classroom to zoonotic diseases transmitted by the Ixodes tick, the health risks of Lyme disease, and disease prevention strategies. Students then participate in a research experience collecting field data and ticks from their community, which are used in university research. To measure changes in student knowledge and attitudes toward Lyme disease and science careers, students completed surveys related to the learning objectives associated with the experience. We found participation in the activity increased student confidence and ability to correctly differentiate a deer tick from a wood tick and to recognize the symptoms of Lyme disease. In addition, students reported increased interest in pursuing a science degree in college or graduate school. Authentic research experience related to a disease relevant to the local community is effective at enhancing high school student engagement in science.

11.
Med Sci Educ ; 26: 135-141, 2016.
Article in English | MEDLINE | ID: mdl-27076992

ABSTRACT

Medical education increasingly involves online learning experiences to facilitate the standardization of curriculum across time and space. In class, delivering material by lecture is less effective at promoting student learning than engaging students in active learning experience and it is unclear whether this difference also exists online. We sought to evaluate medical student preferences for online lecture or online active learning formats and the impact of format on short- and long-term learning gains. Students participated online in either lecture or constructivist learning activities in a first year neurologic sciences course at a US medical school. In 2012, students selected which format to complete and in 2013, students were randomly assigned in a crossover fashion to the modules. In the first iteration, students strongly preferred the lecture modules and valued being told "what they need to know" rather than figuring it out independently. In the crossover iteration, learning gains and knowledge retention were found to be equivalent regardless of format, and students uniformly demonstrated a strong preference for the lecture format, which also on average took less time to complete. When given a choice for online modules, students prefer passive lecture rather than completing constructivist activities, and in the time-limited environment of medical school, this choice results in similar performance on multiple-choice examinations with less time invested. Instructors need to look more carefully at whether assessments and learning strategies are helping students to obtain self-directed learning skills and to consider strategies to help students learn to value active learning in an online environment.

12.
Adv Med Educ Pract ; 6: 597-607, 2015.
Article in English | MEDLINE | ID: mdl-26604852

ABSTRACT

Genetics is an essential subject to be mastered by health professional students of all types. However, technological advances in genomics and recent pedagogical research have changed the way in which many medical training programs teach genetics to their students. These advances favor a more experience-based education focused primarily on developing student's critical thinking skills. In this review, we examine the current state of genetics education at both the preclinical and clinical levels and the ways in which medical and pedagogical research have guided reforms to current and emerging teaching practices in genetics. We discover exciting trends taking place in which genetics is integrated with other scientific disciplines both horizontally and vertically across medical curricula to emphasize training in scientific critical thinking skills among students via the evaluation of clinical evidence and consultation of online databases. These trends will produce future health professionals with the skills and confidence necessary to embrace the new tools of medical practice that have emerged from scientific advances in genetics, genomics, and bioinformatics.

13.
CBE Life Sci Educ ; 12(3): 403-9, 2013.
Article in English | MEDLINE | ID: mdl-24006389

ABSTRACT

Successfully recruiting students from underrepresented groups to pursue biomedical science research careers continues to be a challenge. Early exposure to scientific research is often cited as a powerful means to attract research scholars with the research mentor being critical in facilitating the development of an individual's science identity and career; however, most mentors in the biological sciences have had little formal training in working with research mentees. To better understand mentors' experiences working with undergraduates in the laboratory, we conducted semistructured interviews with 15 research mentors at a public university in the Midwest. The interviewed mentors were part of a program designed to increase the number of American Indians pursuing biomedical/biobehavioral research careers and represented a broad array of perspectives, including equal representation of male and female mentors, mentors from underrepresented groups, mentors at different levels of their careers, and mentors from undergraduate and professional school departments. The mentors identified benefits and challenges in being an effective mentor. We also explored what the term underrepresented means to the mentors and discovered that most of the mentors had an incomplete understanding about how differences in culture could contribute to underrepresented students' experience in the laboratory. Our interviews identify issues relevant to designing programs and courses focused on undergraduate student research.


Subject(s)
Laboratories , Mentors , Minority Groups/education , Research/education , Students , Cultural Diversity , Demography , Female , Humans , Indians, North American/education , Male
14.
J Mol Biol ; 425(1): 19-31, 2013 Jan 09.
Article in English | MEDLINE | ID: mdl-23036859

ABSTRACT

The C-terminal 69 residues of the J-protein Zuo1 are sufficient to activate Pdr1, a transcription factor involved in both pleiotropic drug resistance and growth control. Little is understood about the pathway of activation by this primarily ribosome associated Hsp40 co-chaperone. Here, we report that only the C-terminal 13 residues of Zuo1 are required for activation of Pdr1, with hydrophobic residues being critical for activity. Two-hybrid interaction experiments suggest that the interaction between this 13-residue Zuo1 peptide and Pdr1 is direct, analogous to the activation of Pdr1 by xenobiotics. However, simply dissociation of Zuo1 from the ribosome is not sufficient for induction of Pdr1 transcriptional activity, as the C-terminal 86 residues of Zuo1 fold into an autoinhibitory left-handed four-helix bundle. Hydrophobic residues critical for interaction with Pdr1 are sequestered within the structure of this C-terminal domain (CTD), necessitating unfolding for activation. Thus, although expression of the CTD does not result in activation, alterations that destabilize the structure cause induction of pleiotropic drug resistance. These destabilizing alterations also result in dissociation of the full-length protein from the ribosome. Thus, our results are consistent with an activation pathway in which unfolding of Zuo1's C-terminal helical bundle domain results in ribosome dissociation followed by activation of Pdr1 via a direct interaction.


Subject(s)
DNA-Binding Proteins/genetics , Molecular Chaperones/physiology , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/physiology , Saccharomyces cerevisiae/physiology , Transcription Factors/genetics , Transcriptional Activation/genetics , Amino Acid Sequence , Cycloheximide/pharmacology , Gene Expression Regulation, Fungal , Models, Molecular , Molecular Chaperones/genetics , Molecular Sequence Data , Point Mutation , Protein Interaction Mapping , Protein Structure, Secondary , Protein Structure, Tertiary , Protein Unfolding , Ribosomes/metabolism , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/genetics , Two-Hybrid System Techniques
15.
Genetics ; 192(1): 67-72; quiz 1Sl-3SL, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22714412

ABSTRACT

To make time in class for group activities devoted to critical thinking, we integrated a series of short online lectures into the homework assignments of a large, introductory biology course at a research university. The majority of students viewed the online lectures before coming to class and reported that the online lectures helped them to complete the in-class activity and did not increase the amount of time they devoted to the course. In addition, students who viewed the online lecture performed better on clicker questions designed to test lower-order cognitive skills. The in-class activities then gave the students practice analyzing the information in groups and provided the instructor with feedback about the students' understanding of the material. On the basis of the results of this study, we support creating hybrid course models that allow students to learn the fundamental information outside of class time, thereby creating time during the class period to be dedicated toward the conceptual understanding of the material.


Subject(s)
Biology/education , Internet/statistics & numerical data , Problem-Based Learning/methods , Educational Measurement , Humans , Online Systems/statistics & numerical data , Students/psychology , Universities/statistics & numerical data
16.
Proc Natl Acad Sci U S A ; 109(2): 472-7, 2012 Jan 10.
Article in English | MEDLINE | ID: mdl-22203981

ABSTRACT

Zuo1 functions as a J-protein cochaperone of its partner Hsp70. In addition, the C terminus of Zuo1 and the N terminus of Ssz1, with which Zuo1 forms a heterodimer, can independently activate the Saccharomyces cerevisiae transcription factor pleiotropic drug resistance 1 (Pdr1). Here we report that activation of Pdr1 by Zuo1 or Ssz1 causes premature growth arrest of cells during the diauxic shift, as they adapt to the changing environmental conditions. Conversely, cells lacking Zuo1 or Ssz1 overgrow, arresting at a higher cell density, an effect overcome by activation of Pdr1. Cells lacking the genes encoding plasma membrane transporters Pdr5 and Snq2, two targets of Pdr1, also overgrow at the diauxic shift. Adding conditioned medium harvested from cultures of wild-type cells attenuated the overgrowth of both zuo1Δssz1Δ and pdr5Δsnq2Δ cells, suggesting the extracellular presence of molecules that signal growth arrest. In addition, our yeast two-hybrid analysis revealed an interaction between Pdr1 and both Zuo1 and Ssz1. Together, our results support a model in which (i) membrane transporters, encoded by Pdr1 target genes act to promote cell-cell communication by exporting quorum sensing molecules, in addition to playing a role in pleiotropic drug resistance; and (ii) molecular chaperones function at promoters to regulate this intercellular communication through their activation of the transcription factor Pdr1.


Subject(s)
DNA-Binding Proteins/metabolism , Gene Expression Regulation, Fungal/physiology , HSP70 Heat-Shock Proteins/metabolism , Molecular Chaperones/metabolism , Quorum Sensing/physiology , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/growth & development , Transcription Factors/metabolism , ATP-Binding Cassette Transporters/metabolism , Chromatin Immunoprecipitation , Cycloheximide , Drug Resistance, Fungal/physiology , HSP70 Heat-Shock Proteins/genetics , Microarray Analysis , Molecular Chaperones/genetics , Mutagenesis, Site-Directed , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/genetics , Two-Hybrid System Techniques
17.
Cancer Res ; 69(14): 5768-75, 2009 Jul 15.
Article in English | MEDLINE | ID: mdl-19584276

ABSTRACT

C57BL/6J mice carrying the Min allele of Adenomatous polyposis coli (Apc) develop numerous adenomas along the entire length of the intestine and consequently die at an early age. This short lifespan would prevent the accumulation of somatic genetic mutations or epigenetic alterations necessary for tumor progression. To overcome this limitation, we generated F(1) Apc(Min/+) hybrids by crossing C57BR/cdcJ and SWR/J females to C57BL/6J Apc(Min/+) males. These hybrids developed few intestinal tumors and often lived longer than 1 year. Many of the tumors (24-87%) were invasive adenocarcinomas, in which neoplastic tissue penetrated through the muscle wall into the mesentery. In a few cases (3%), lesions metastasized by extension to regional lymph nodes. The development of these familial cancers does not require chromosomal gains or losses, a high level of microsatellite instability, or the presence of Helicobacter. To test whether genetic instability might accelerate tumor progression, we generated Apc(Min/+) mice homozygous for the hypomorphic allele of the Nijmegen breakage syndrome gene (Nbs1(DeltaB)) and also treated Apc(Min/+) mice with a strong somatic mutagen. These imposed genetic instabilities did not reduce the time required for cancers to form nor increase the percentage of cancers nor drive progression to the point of distant metastasis. In summary, we have found that the Apc(Min/+) mouse model for familial intestinal cancer can develop frequent invasive cancers in the absence of overt genomic instability. Possible factors that promote invasion include age-dependent epigenetic changes, conservative somatic recombination, or direct effects of alleles in the F(1) hybrid genetic background.


Subject(s)
Adenomatous Polyposis Coli Protein/genetics , Intestinal Neoplasms/genetics , Mutation , Signal Transduction/genetics , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Adenoma/genetics , Adenoma/pathology , Alkylating Agents/toxicity , Animals , Cell Cycle Proteins/genetics , DNA-Binding Proteins , Disease Models, Animal , Disease Progression , Ethylnitrosourea/toxicity , Feces/microbiology , Female , Helicobacter Infections/genetics , Helicobacter Infections/pathology , Helicobacter pylori/isolation & purification , Humans , Intestinal Neoplasms/pathology , Intestines/drug effects , Intestines/microbiology , Intestines/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Inbred Strains , Nuclear Proteins/genetics , Survival Analysis , Time Factors
18.
Carcinogenesis ; 29(9): 1825-30, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18310091

ABSTRACT

Using a mouse predisposed to neoplasia by a germ line mutation in Apc (Apc(Min)), we tested whether induced hyperplasia is sufficient to increase intestinal tumor multiplicity or size in the intestine. We found that hyperplasia in the jejunum correlated with a significant increase in tumor multiplicity. However, tumor multiplicity was unchanged in the hyperplastic colon. This result indicates that even an intestine predisposed to neoplasia can, in certain regions including the colon, accommodate net increased cell growth without developing more neoplasms. Where hyperplasia correlated with increased tumor multiplicity, it did not increase the size or net growth of established tumors. This result suggests that the event linking hyperplasia and neoplasia in the jejunum is tumor establishment. Two novel observations arose in our study: the multiple intestinal neoplasia (Min) mutation partially suppressed both mitosis and transforming growth factor alpha-induced hyperplasia throughout the intestine; and zinc treatment alone increased tumor multiplicity in the duodenum of Min mice.


Subject(s)
Colonic Neoplasms/pathology , Duodenal Neoplasms/pathology , Genes, APC/physiology , Hyperplasia/chemically induced , Ileal Neoplasms/pathology , Jejunal Neoplasms/pathology , Transforming Growth Factor alpha/physiology , Animals , Apoptosis/physiology , Colonic Neoplasms/etiology , Duodenal Neoplasms/etiology , Ethylnitrosourea , Female , Hyperplasia/pathology , Ileal Neoplasms/etiology , Jejunal Neoplasms/etiology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Mitosis , Mutation , Transgenes/physiology , Zinc/administration & dosage
19.
Methods ; 39(4): 284-90, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16879978

ABSTRACT

Xenopus egg extract provides an extremely powerful approach in the study of cell cycle regulated aspects of nuclear form and function. Each egg contains enough membrane and protein components to support multiple rounds of cell division. Remarkably, incubation of egg extract with DNA in the presence of an energy regeneration system is sufficient to induce formation of a nuclear envelope around DNA. In addition, these in vitro nuclei contain functional nuclear pore complexes, which form de novo and are capable of supporting nucleocytoplasmic transport. Mitotic entry can be induced by the addition of recombinant cyclin to an interphase extract. This initiates signaling that leads to disassembly of the nuclei. Thus, this cell-free system can be used to decipher events involved in mitotic remodeling of the nuclear envelope such as changes in nuclear pore permeability, dispersal of membrane, and disassembly of the lamina. Both general mechanisms and individual players required for orchestrating these events can be identified via biochemical manipulation of the egg extract. Here, we describe a procedure for the assembly and disassembly of in vitro nuclei, including the production of Xenopus egg extract and sperm chromatin DNA.


Subject(s)
Cell Extracts/chemistry , Cell Nucleus/metabolism , Cell-Free System/metabolism , Ovum/chemistry , Animals , Cell Fractionation , Cell-Free System/chemistry , Chromatin/metabolism , DNA/metabolism , DNA-Binding Proteins/metabolism , Female , In Vitro Techniques , Male , Nuclear Envelope/metabolism , Nuclear Pore/metabolism , Sperm-Ovum Interactions , Spermatozoa/chemistry , Xenopus
20.
Curr Opin Cell Biol ; 18(1): 108-16, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16364623

ABSTRACT

The membrane system that encloses genomic DNA is referred to as the nuclear envelope. However, with emerging roles in signaling and gene expression, these membranes clearly serve as more than just a physical barrier separating the nucleus and cytoplasm. Recent progress in our understanding of nuclear envelope architecture and composition has also revealed an intriguing connection between constituents of the nuclear envelope and human disease, providing further impetus to decipher this cellular structure and the dramatic remodeling process it undergoes with each cell division.


Subject(s)
Cell Nucleus/metabolism , Nuclear Envelope/chemistry , Nuclear Envelope/physiology , Animals , Humans , Models, Biological
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