Search

Objective: The Spirit Catches You and You Fall Down by Anne Fadiman is a critically acclaimed book describing the importance of understanding cultural influence on health care and health outcomes. Although this book has been incorporated into standard curriculum in the university and medical school training settings, consideration of how The Spirit Catches You and You Fall Down might change undergraduate student perceptions on health disparities, specifically among students at a minority-serving institution in the USA, has yet to be explored. Method: A qualitative, thematic analysis, using a pre-/post-test study design, assessed undergraduate students’ perceptions of topics of health disparities, spirituality and trust in healthcare providers. A total of 43 student responses characterising their perceptions on these topics were used to define themes both before and after a course utilising Fadiman’s book as a teaching tool. Results: Changes within the themes present in the post-test data showed that students had a deeper understanding of the need for communication with healthcare providers, as well as the need to build bridges between traditional spirituality and faith with modern medicine, in the context of respecting one’s culture, to effectively promote health outcomes in a multicultural society. Conclusion: An undergraduate course with directed lesson plans taken from The Spirit Catches You and You Fall Down afforded undergraduate students at a US minority-serving institution with a way to contextualise why and how cultural differences can lead to health disparities.

Objective: The Immortal Life of Henrietta Lacks by Rebecca Skloot is an award-winning biography engaging its readers on important topics ranging from race, science and ethics to the social determinants of health. However, the multiple pedagogic impacts of this book on the public health classroom setting have yet to be comprehensively explored. Method: A qualitative, pre/post-test study design assessed the perceptions of 17 Master’s of Public Health students on topics of health disparities and medical ethics. A total of 14 students were assigned to an intervention (book-based seminar course; Cohort A) and 3 students acted as the non-intervention group (Cohort B) over a study period of 10 weeks. Results: A thematic analysis uncovered more profound changes in the perceptions of the intervention group. All students were aware of health disparities over the course of the 10-week class; however, significant traction was gained on more complex issues linked to the social determinants of health. Specifically, students in the intervention group showed deeper perceptions about health inequalities with a particular focus on racial disparities. Conclusion: Although graduate students in the public health discipline were well aware of health inequalities, a seminar course surrounding a popular book about Henrietta Lacks afforded students a more concrete understanding for why and how race and racism in health disparities exist.

Objective: Multiple factors such as socioeconomic status (SES), education, race, and ethnicity can affect colorectal cancer screening (CRCS) rates. However, few studies have addressed CRCS disparities among Arab Americans. Our aim was to understand how Arab Americans view CRCS. Method: Employing thematic analysis, we collected and analyzed the dialogue of Arab American focus groups and interviews to better understand participants’ perceptions of CRCS. Themes were generated and categorized into barriers and facilitators. Results: Eleven Arab American males participated in two focus groups and two interviews. Three barriers included disbelief in modern medicine, concerns about the procedure, and lack of communication with the physician. Three facilitators were also identified: compliance and priority of health, access to healthcare, and awareness. Conclusion: Disparities in CRCS cannot solely be explained by SES and access but cultural differences also contribute. Specific interventions accounting for these cultural differences are needed to reduce disparities in CRCS among Arab Americans.

The vertebrate nuclear pore protein Nup153 contains a novel RNA binding domain. This 150-amino acid region was previously found to bind preferentially to a panel of mRNAs when compared with structured RNAs, such as tRNA, U snRNA, and double-stranded RNA. The ability to broadly recognize mRNA led to the conclusion that the Nup153 RNA binding domain confers a general affinity for single-stranded RNA. Here, we have probed Nup153 RNA recognition to decipher how this unique RNA binding domain discriminates between potential targets. We first mapped the binding determinant within an RNA fragment that associates relatively robustly with the Nup153 RNA binding domain. We next designed synthetic RNA oligonucleotides to systematically delineate the features within this minimal RNA fragment that are key to Nup153 RNA-binding domain binding and demonstrated that the binding preferences of Nup153 do not reflect general preferences of an mRNA/single-stranded RNA-binding protein. We further found that the association between Nup153 and a cellular mRNA can be attributed to an interaction with specific subregions of the RNA. These results indicate that Nup153 can discriminate between mRNA and other classes of RNA transcripts due in part to direct recognition of a loose sequence motif. This information adds a new dimension to the interfaces that can contribute to recognition in mRNA export cargo selection and fate.

In eukaryotes, the multivesicular body (MVB) sorting pathway plays an essential role in regulating cell surface protein composition, thereby impacting numerous cellular functions. Vps4, an ATPase associated with a variety of cellular activities, is required late in the MVB sorting reaction to dissociate the endosomal sorting complex required for transport (ESCRT), a requisite for proper function of this pathway. However, regulation of Vps4 function is not understood. We characterize Vta1 as a positive regulator of Vps4 both in vivo and in vitro. Vta1 promotes proper assembly of Vps4 and stimulates its ATPase activity through the conserved Vta1/SBP1/LIP5 region present in Vta1 homologues across evolution, including human SBP1 and Arabidopsis thaliana LIP5. These results suggest an evolutionarily conserved mechanism through which the disassembly of the ESCRT proteins, and thereby MVB sorting, is regulated by the Vta1/SBP1/LIP5 proteins.

Separation of the nucleus and cytoplasm, maintained by two membrane bilayers that form the nuclear envelope, allows for spatial control over transcription factors and signaling molecules. This compartmentalization further ensures the presence of specialized environments for different stages of gene expression, such as transcription and protein production. Selective exchange between these two compartments is clearly important as well. Whereas many types of active transport between the nucleus and cytoplasm rely on transport receptors in the importin-β superfamily, export of mRNA utilizes distinct soluble machinery (6, 92). Moreover, in general mRNA export does not depend on a specific motif in the cargo, as has been demonstrated in many other cases of receptor-cargo interactions (22). Recent progress in identifying soluble factors important to mRNA trafficking is beginning to reveal the molecular basis for functional coupling between steps in mRNA biogenesis and how such coupling, rather than a consensus motif, brings specificity to mRNA export. Studies with Saccharomyces cerevisiae revealed that the key modulators of cellular mRNA export are unrelated to canonical importin-β-related receptors. Specifically, yeast deficient in a gene called MEX67 accumulate poly(A)+ RNA in the nucleus (73). A second protein, Mtr2p, binds Mex67p, and this interaction is required for the export of poly(A)+ RNA in yeast (71, 77). In an independent avenue of investigation, involving metazoan cells and the simian type D retrovirus Mason Pfizer monkey virus, the cellular protein TAP was found to facilitate export of RNA containing the viral constitutive transport element (CTE) (8, 32). TAP, confirmed to be the human orthologue of Mex67p, has been redesignated NXF1 (nuclear export factor 1). NXF1 interacts with p15/NXT1, the presumed functional homologue of Mtr2p (33, 44). Although Mtr2p and p15 share no sequence similarity, the Mex67p-Mtr2p complex displays similar structural architecture to the NXF1-p15 heterodimer (21). Indeed, the mRNA export defect in yeast cells deficient in both Mex67p and Mtr2p can be rescued by expression of human NXF1 and its cofactor p15 (44). Expression knock-down studies using RNA interference have demonstrated that NXF1 and p15 are required for poly(A)+ RNA export (35, 84, 93), further strengthening the case for an evolutionarily conserved system of mRNA export that is distinct from the importin-β superfamily. Likewise, studies with Xenopus oocytes support the conclusion that the small GTPase Ran, a key modulator of importin-β-type receptors, is not key to mRNA export (10). However, the distinction between mRNA export and the importin-β family/Ran network is not absolute, as an importin-β family member has recently been implicated in mRNA export as well (74).

The ESCRT protein complexes are recruited from the cytoplasm and assemble on the endosomal membrane into a protein network that functions in sorting of ubiquitinated transmembrane proteins into the multivesicular body (MVB) pathway. This transport pathway packages cargo proteins into vesicles that bud from the MVB limiting membrane into the lumen of the compartment and delivers these vesicles to the lysosome/vacuole for degradation. The dissociation of ESCRT machinery by the AAA-type ATPase Vps4 is a necessary late step in the formation of MVB vesicles. This ATP-consuming step is regulated by several Vps4-interacting proteins, including the newly identified regulator Ist1. Our data suggest that Ist1 has a dual role in the regulation of Vps4 activity: it localizes to the ESCRT machinery via Did2 where it positively regulates recruitment of Vps4 and it negatively regulates Vps4 by forming an Ist1-Vps4 heterodimer, in which Vps4 cannot bind to the ESCRT machinery. The activity of the MVB pathway might be in part determined by outcome of these two competing activities.

INTRODUCTION: BCR-ABL Tyrosine Kinase Inhibitors (TKI) have demonstrated efficacy in patients with chronic myeloid leukemia (CML) in the clinical trial setting. However, additional real world data evaluating first line TKI treatment patterns are still needed. Moreover, real world data captured within integrated, managed care organizations are scarce. This study evaluates treatment patterns among newly diagnosed CML patients initiated on frontline TKI therapy within the Kaiser Permanente Southern California (KPSC) integrated managed care organization. METHODS: A retrospective analysis was conducted using KPSC data between 1/1/2007 to 12/31/2014. Patients were identified with CML diagnosis from the KPSC cancer registry database during 1/1/2007 to 12/31/2013. Patients > 18 years on date of CML diagnosis, with no history of other prior cancers or stem cell transplant during the 12 months prior to diagnosis date were eligible for inclusion. Index date was defined as the date of the first TKI prescription identified during the period 1/1/2007 to 12/31/2013, and no history of TKI use in the prior 12 months. All patients had continuous membership and drug benefit eligibility 12 months prior to index date. Patients were followed from their index date until one of the following outcomes: 1) death, 2) disenrollment from health plan, 3) switch to another TKI, 4) discontinuation of index TKI therapy, or 5) end of study period of 12/31/2014. Discontinuation, switch and persistence of index TKI therapy were defined using a 60 day gap calculation: estimated date of depleting the second to last prescription supply, plus days' supply of the last prescription, plus 60 days. If a patient did not fill any TKI prescription before or during the 60 day gap, this was labeled as a discontinuation. If a patient filled a different TKI prescription before or during the 60 day gap, this was labeled as switch, and if a patient refilled their index TKI prescription, then this was labeled as continuation of index therapy. RESULTS: 216 patients were identified with incident CML and with first line TKI therapy: 19 (8.8%) on dasatinib, 189 (87.5%) on imatinib, and 8 (3.7%) on nilotinib. The mean age on diagnosis date was 53 years and 63% were male. The mean age for patients who initiated nilotinib was 45.5 years, 48.3 years for dasatinib, and 54.1 years for imatinib. The Charlson comorbidity index was highest for patients on dasatinib (3.0) but similar for the patients initiated on imatinib and nilotinib (2.51 and 2.50). The mean days until an outcome was identified was 347 (SD ± 311). 93 patients (43%) continued their index therapy; 95 patients (44%) discontinued their index therapy, 3 patients (1.4%) switched their index therapy, 7 patients (3.2%) died during follow up, and 18 patients (8.3%) disenrolled from the health plan. The majority of the patients were initiated on imatinib and 45% of these patients discontinued their index therapy per our study definition. CONCLUSIONS: 44% of incident CML patients initiated on TKIs discontinued therapy by an average of 347 days (less than 1 year) from the start of treatment. Imatinib was the initial TKI therapy for 87.5% of the patients. Additional data will be presented which may assist in healthcare decision making for those newly diagnosed CML patients initiating first line TKI therapy in a managed care setting. Figure 1: Summary Table of Outcomes from First Line Index TKI Therapy Disclosures Dimaano: Bristol Myers Squibb: Employment, Equity Ownership. Felber:Bristol Myers Squibb: Employment, Equity Ownership.

Despite the apparent overall structural stability of the nuclear pore complex during interphase, at least two nucleoporins have been shown to move dynamically on and off the pore. It is not yet certain what contribution nucleoporin mobility makes to the process of nuclear transport or how such mobility is regulated. Previously, we showed that Nup98 dynamically interacts with the NPC as well as bodies within the nucleus in a transcription-dependent manner. We have extended our studies of dynamics to include Nup153, another mobile nucleoporin implicated in RNA export. In both cases, we found that although only one domain is essential for NPC localization, other regions of the protein significantly affect the stability of association with the pore. Interestingly, like Nup98, the exchange of Nup153 on and off the pore is inhibited when transcription by Pol I and Pol II is blocked. We have mapped the regions required to link Nup98 and Nup153 mobility to transcription and found that the requirements differ depending on which polymerases are inhibited. Our data support a model whereby transcription of RNA is coupled to nucleoporin mobility, perhaps ultimately linking transport of RNAs to a cycle of remodeling at the nuclear pore basket.

The nuclear pore protein Nup153 is important for the transport of protein and RNA between the nucleus and cytoplasm. Recently, a novel RNA binding domain (RBD) was mapped within the N-terminal region of Nup153; however, the determinants of RNA association were not characterized. Here we have tested a range of RNAs with different general features to better understand targets recognized by this domain. We have found that the RBD associates with single-stranded RNA with little sequence preference. These results provide new information about a novel RNA binding domain and suggest new models to consider for the contribution of Nup153 to nucleocytoplasmic transport.

Traffic between the nucleus and cytoplasm takes place through a macromolecular structure termed the nuclear pore complex. To understand how the vital process of nucleocytoplasmic transport occurs, the contribution of individual pore proteins must be elucidated. One such protein, the nucleoporin Nup153, is localized to the nuclear basket of the pore complex and has been shown to be a central component of the nuclear transport machinery. Perturbation of Nup153 function was demonstrated previously to block the export of several classes of RNA cargo. Moreover, these studies also showed that Nup153 can stably associate with RNA in vitro. In this study, we have mapped a domain within Nup153, encompassing amino acids 250-400 in human Nup153, that is responsible for RNA association. After cloning this region of Xenopus Nup153, we performed a cross-species analysis. Despite variation in sequence conservation between Drosophila, Xenopus, and human, this domain of Nup153 displayed robust RNA binding activity in each case, indicating that this property is a hallmark feature of Nup153 and pointing toward a subset of amino acid residues that are key to conferring this ability. We have further determined that a recombinant fragment of Nup153 can bind directly to RNA and that this fragment can interact with endogenous RNA targets. Our findings identify a functionally conserved domain in Nup153 and suggest a role for RNA binding in Nup153 function at the nuclear pore.

Beta-2 microglobulin (beta2m)has been shown to have an effect on the structural and functional constraints that facilitate proper class I antigen presentation. To date, no evidence has pinpointed the beta2m-specific amino acids that play an integral role in affecting structure in and around the peptide binding region of class I. To delineate beta2m amino acid positions that affect the alpha-1 helical region, we generated a series of mutant beta2m proteins bearing precise amino acid substitutions. The amino acid positions chosen were based upon previous results which demonstrated that human beta2m association with H2-Ld altered the structure of the alpha-1/alpha-2 super-domain. beta2m mutant proteins were used in beta2m exchange assays with cells expressing H2-Ld. Following exchange, cells were assayed to determine whether mutant beta2m association resulted in structural alteration of class I extracellular domains. The alteration in H2-Ld structure was evidenced by an increase in the binding of an antibody (34-1-2), specific for the alpha-1 helical region of H2-Ld. Results demonstrated that amino acid substitutions in beta2m positions 33 and 53 led to a dramatic increase in the reactivity of the alpha-1 domain-specific antibody 34-1-2. Identifying beta2m amino acid positions that influence the structure of the peptide binding region may allow for a better understanding of cellular immune responses that center upon class I/beta2m expression.