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1.
J Biol Chem ; 299(3): 102910, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36642182

RESUMO

Lipids are important nutrients for Mycobacterium tuberculosis (Mtb) to support bacterial survival in mammalian tissues and host cells. Fatty acids and cholesterol are imported across the Mtb cell wall via the dedicated Mce1 and Mce4 transporters, respectively. It is thought that the Mce1 and Mce4 transporters are comprised of subunits that confer substrate specificity and proteins that couple lipid transport to ATP hydrolysis, similar to other bacterial ABC transporters. However, unlike canonical bacterial ABC transporters, Mce1 and Mce4 appear to share a single ATPase, MceG. Previously, it was established that Mce1 and Mce4 are destabilized when key transporter subunits are rendered nonfunctional; therefore, we investigated here the role of MceG in Mce1 and Mce4 protein stability. We determined that key residues in the Walker B domain of MceG are required for the Mce1- and Mce4-mediated transport of fatty acids and cholesterol. Previously, it has been established that Mce1 and Mce4 are destabilized and/or degraded when key transporter subunits are rendered nonfunctional, thus we investigated a role for MceG in stabilizing Mce1 and Mce4. Using an unbiased quantitative proteomic approach, we demonstrate that Mce1 and Mce4 proteins are specifically degraded in mutants lacking MceG. Furthermore, bacteria expressing Walker B mutant variants of MceG failed to stabilize Mce1 and Mce4, and we show that deleting MceG impacts the fitness of Mtb in the lungs of mice. Thus, we conclude that MceG represents an enzymatic weakness that can be potentially leveraged to disable and destabilize both the Mce1 and Mce4 transporters in Mtb.


Assuntos
Proteínas de Bactérias , Mycobacterium tuberculosis , Animais , Camundongos , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Colesterol/genética , Colesterol/metabolismo , Ácidos Graxos/genética , Ácidos Graxos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Proteômica
2.
J Biol Chem ; 298(1): 101438, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34808209

RESUMO

Hereditary spastic paraplegia (HSP) comprises a heterogeneous group of neuropathies affecting upper motor neurons and causing progressive gait disorder. Mutations in the gene SPG3A/atlastin-1 (ATL1), encoding a dynamin superfamily member, which utilizes the energy from GTP hydrolysis for membrane tethering and fusion to promote the formation of a highly branched, smooth endoplasmic reticulum (ER), account for approximately 10% of all HSP cases. The continued discovery and characterization of novel disease mutations are crucial for our understanding of HSP pathogenesis and potential treatments. Here, we report a novel disease-causing, in-frame insertion in the ATL1 gene, leading to inclusion of an additional asparagine residue at position 417 (N417ins). This mutation correlates with complex, early-onset spastic quadriplegia affecting all four extremities, generalized dystonia, and a thinning of the corpus callosum. We show using limited proteolysis and FRET-based studies that this novel insertion affects a region in the protein central to intramolecular interactions and GTPase-driven conformational change, and that this insertion mutation is associated with an aberrant prehydrolysis state. While GTPase activity remains unaffected by the insertion, membrane tethering is increased, indicative of a gain-of-function disease mechanism uncommon for ATL1-associated pathologies. In conclusion, our results identify a novel insertion mutation with altered membrane tethering activity that is associated with spastic quadriplegia, potentially uncovering a broad spectrum of molecular mechanisms that may affect neuronal function.


Assuntos
Proteínas de Ligação ao GTP , Proteínas de Membrana , Mutação , Paraplegia Espástica Hereditária , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Ligação ao GTP/genética , Proteínas de Ligação ao GTP/metabolismo , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutagênese Insercional , Conformação Proteica , Paraplegia Espástica Hereditária/genética , Paraplegia Espástica Hereditária/metabolismo
3.
Adv Health Sci Educ Theory Pract ; 27(4): 1033-1048, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35753003

RESUMO

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.


Assuntos
Desempenho Acadêmico , Educação de Graduação em Medicina , Estudantes de Medicina , Humanos , Estados Unidos , Faculdades de Medicina , Avaliação Educacional/métodos , Teste de Admissão Acadêmica
4.
J Bacteriol ; 200(8)2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29437852

RESUMO

LapA of Pseudomonas fluorescens Pf0-1 belongs to a diverse family of cell surface-associated bacterial adhesins that are secreted via the type I secretion system (T1SS). We previously reported that the periplasmic protease LapG cleaves the N terminus of LapA at a canonical dialanine motif to release the adhesin from the cell surface under conditions unfavorable to biofilm formation, thus decreasing biofilm formation. Here, we characterize LapA as the first type I secreted substrate that does not follow the "one-step" rule of T1SS. Rather, a novel N-terminal element, called the retention module (RM), localizes LapA at the cell surface as a secretion intermediate. Our genetic, biochemical, and molecular modeling analyses support a model wherein LapA is tethered to the cell surface through its T1SS outer membrane TolC-like pore, LapE, until LapG cleaves LapA in the periplasm. We further demonstrate that this unusual retention strategy is likely conserved among LapA-like proteins, and it reveals a new subclass of T1SS ABC transporters involved in transporting this group of surface-associated LapA-like adhesins. These studies demonstrate a novel cell surface retention strategy used throughout the Proteobacteria and highlight a previously unappreciated flexibility of function for T1SS.IMPORTANCE Bacteria have evolved multiple secretion strategies to interact with their environment. For many bacteria, the secretion of cell surface-associated adhesins is key for initiating contact with a preferred substratum to facilitate biofilm formation. Our work demonstrates that P. fluorescens uses a previously unrecognized secretion strategy to retain the giant adhesin LapA at its cell surface. Further, we identify likely LapA-like adhesins in various pathogenic and commensal proteobacteria and provide phylogenetic evidence that these adhesins are secreted by a new subclass of T1SS ABC transporters.


Assuntos
Adesinas Bacterianas/metabolismo , Proteínas de Bactérias/metabolismo , Pseudomonas fluorescens/fisiologia , Sistemas de Secreção Tipo I/fisiologia , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Membrana Celular , Regulação Bacteriana da Expressão Gênica/fisiologia , Modelos Moleculares , Conformação Proteica , Transporte Proteico
5.
Adv Health Sci Educ Theory Pract ; 23(3): 499-511, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29340892

RESUMO

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.


Assuntos
Sucesso Acadêmico , Diversidade Cultural , Faculdades de Medicina/organização & administração , Adulto , Feminino , Humanos , Modelos Lineares , Masculino , Avaliação de Programas e Projetos de Saúde , Fatores Socioeconômicos , Adulto Jovem
6.
Med Teach ; 39(8): 813-819, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28440094

RESUMO

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.


Assuntos
Currículo , Docentes de Medicina , Estudantes de Medicina , Educação de Graduação em Medicina , Humanos , Aprendizagem Baseada em Problemas
7.
BMC Med Educ ; 17(1): 190, 2017 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-29110662

RESUMO

BACKGROUND: Many medical schools use admissions Multiple Mini-Interviews (MMIs) rather than traditional interviews (TIs), partly because MMIs are thought to be more reliable. Yet prior studies examined single-school samples of candidates completing either an MMI or TI (not both). Using data from five California public medical schools, the authors examined the within- and between-school reliabilities of TIs and MMIs. METHODS: The analyses included applicants interviewing at ≥1 of the five schools during 2011-2013. Three schools employed TIs (TI1, TI2, TI3) and two employed MMIs (MMI1, MMI2). Mixed linear models accounting for nesting of observations within applicants examined standardized TI and MMI scores (mean = 0, SD = 1), adjusting for applicant socio-demographics, academic metrics, year, number of interviews, and interview date. RESULTS: A total of 4993 individuals (completing 7516 interviews [TI = 4137, MMI = 3379]) interviewed at ≥1 school; 428 (14.5%) interviewed at both MMI schools and 687 (20.2%) at more than one TI school. Within schools, inter-interviewer consistency was generally qualitatively lower for TI1, TI2, and TI3 (Pearson's r 0.07, 0.13, and 0.29, and Cronbach's α, 0.40, 0.44, and 0.61, respectively) than for MMI1 and MMI 2 (Cronbach's α 0.68 and 0.60, respectively). Between schools, the adjusted intraclass correlation coefficient was 0.27 (95% CI 0.20-0.35) for TIs and 0.47 (95% CI 0.41-0.54) for MMIs. CONCLUSIONS: Within and between-school reliability was qualitatively higher for MMIs than for TIs. Nonetheless, TI reliabilities were higher than anticipated from prior literature, suggesting TIs may not need to be abandoned on reliability grounds if other factors favor their use.


Assuntos
Educação de Graduação em Medicina , Entrevistas como Assunto/métodos , Critérios de Admissão Escolar , Faculdades de Medicina , Adolescente , Adulto , California , Humanos , Reprodutibilidade dos Testes , Adulto Jovem
8.
J Surg Res ; 202(2): 253-8, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-27229098

RESUMO

BACKGROUND: Given more emphasis on training primary care physicians for underserved areas, we hypothesized that students self-identifying as "disadvantaged" would be less likely to pursue surgical training. METHODS: We retrospectively reviewed medical school data on students graduating 2005-2014. Students were stratified into "disadvantaged" and "nondisadvantaged". Data were recorded on age, grade point average, Medical College Admission Test (MCAT), gender, surgery grade, United States Medical Licensing Examination step 1 score, and residency match into a surgical field. A comparison of the proportion of students matching into a surgical field was assessed with chi-square test. Multivariate logistic regression was performed to assess the factors that predict the choice of general surgery versus another surgical field. RESULTS: Of the 1140 students who graduated during the study period, 219 (19.2%) students self-identified as "disadvantaged". Of all students, 158 (13.9%) chose a surgical field. The disadvantaged group was older at entry and had lower grade point average and total MCAT scores. Twenty-seven (12.3%) disadvantaged students chose a surgical residency versus 130 (14.1%) nondisadvantaged students (P = 0.56). On multivariate logistic regression, female gender (odds ratio [OR] = 3.9; 95% confidence interval = [1.9-8.3], P < 0.01), disadvantaged status (OR = 2.8 [1.1-7.1], P = 0.03), and United States Medical Licensing Examination step 1 score ≥ 227 (OR = 0.43 [0.21-0.88], P = 0.02) were significantly associated with matching into general surgery versus another surgical specialty. DISCUSSION: Although the disadvantaged cohort was older and had lower undergraduate GPAs and MCAT scores, the proportion of disadvantaged students matching into a surgical residency was not statistically different. To address the future shortage of general surgeons in underserved areas, increasing enrollment of "disadvantaged" students may alleviate the "surgical desert".


Assuntos
Escolha da Profissão , Internato e Residência , Classe Social , Especialidades Cirúrgicas/educação , Estudantes de Medicina , Populações Vulneráveis , Adulto , California , Feminino , Cirurgia Geral/educação , Humanos , Modelos Logísticos , Masculino , Área Carente de Assistência Médica , Estudos Retrospectivos
9.
BMC Med Educ ; 14: 127, 2014 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-24980918

RESUMO

BACKGROUND: To assess the impact of a change in preclerkship grading system from Honors/Pass/Fail (H/P/F) to Pass/Fail (P/F) on University of California, San Diego (UCSD) medical students' academic performance. METHODS: Academic performance of students in the classes of 2011 and 2012 (constant-grading classes) were collected and compared with performance of students in the class of 2013 (grading-change class) because the grading policy at UCSD SOM was changed for the class of 2013, from H/P/F during the first year (MS1) to P/F during the second year (MS2). For all students, data consisted of test scores from required preclinical courses from MS1 and MS2 years, and USMLE Step 1 scores. Linear regression analysis controlled for other factors that could be predictive of student performance (i.e., MCAT scores, undergraduate GPA, age, gender, etc.) in order to isolate the effect of the changed grading policy on academic performance. The change in grading policy in the MS2 year only, without any corresponding changes to the medical curriculum, presents a unique natural experiment with which to cleanly evaluate the effect of P/F grading on performance outcomes. RESULTS: After controlling for other factors, the grading policy change to P/F grading in the MS2 year had a negative impact on second-year grades relative to first-year grades (the constant-grading classes performed 1.65% points lower during their MS2 year compared to the MS1 year versus 3.25% points lower for the grading-change class, p < 0.0001), but had no observable impact on USMLE Step 1 scores. CONCLUSIONS: A change in grading from H/P/F grading to P/F grading was associated with decreased performance on preclinical examinations but no decrease in performance on the USMLE Step 1 examination. These results are discussed in the broader context of the multitude of factors that should be considered in assessing the merits of various grading systems, and ultimately the authors recommend the continuation of pass-fail grading at UCSD School of Medicine.


Assuntos
Competência Clínica/normas , Avaliação Educacional/métodos , Faculdades de Medicina/normas , California , Competência Clínica/estatística & dados numéricos , Educação Médica/organização & administração , Educação Médica/normas , Educação Médica/estatística & dados numéricos , Avaliação Educacional/normas , Escolaridade , Feminino , Humanos , Masculino , Faculdades de Medicina/organização & administração , Adulto Jovem
10.
J Interpers Violence ; 39(7-8): 1811-1829, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37970834

RESUMO

Community and healthcare organizations have not historically collaborated effectively, leaving gaps in the continuum of care for survivors of sexual assault. These gaps are particularly acutely felt by transgender (trans) survivors, who experience additional barriers to care and face higher rates of sexual assault. To bridge these gaps and enhance the provision of comprehensive support for trans people, we developed an intersectoral network of trans-positive community and hospital-based organizations in Ontario, Canada. As part of a baseline evaluation of the network, we conducted a social network analysis to determine the extent and nature of collaboration between members within and across these two sectors. Using a validated social network analysis tool (PARTNER survey), data were collected from June 22 to July 22, 2021. The extent of collaboration was examined by relationship type: intrasectoral (same sector) and intersectoral (different sectors). The nature of collaboration was examined using relational scores (value: power, level of involvement, potential resource contribution; trust: reliability, mission congruence, openness to discussion). Fifty-four community organizations (65.9% of 82 invited) and 24 hospital-based violence treatment centers (64.9% of 37 invited) responded. The majority of collaborations were within, rather than across, the two sectors: of all 378 collaborations described, 70.9% (n = 268) were intrasectoral collaborations and 29.1% (n = 110) were intersectoral collaborations. Intersectoral relationships were characterized by lower scores for level of involvement, trust, reliability, and mission congruence than intrasectoral relationships, but higher scores for power. These findings were shared in a virtual consultation session of key stakeholders, in which some participants expressed "surprise" and concern for the lack of collaboration and character of relationships across sectors. Recommendations to increase intersectoral collaboration, which included intersectoral program planning and service design and supporting increased opportunities for intersectoral training and knowledge exchange, are presented.


Assuntos
Delitos Sexuais , Pessoas Transgênero , Humanos , Reprodutibilidade dos Testes , Ontário , Violência , Sobreviventes , Hospitais
11.
Med Educ ; 46(9): 878-86, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22891908

RESUMO

CONTEXT: Medical College Admission Test (MCAT) scores are widely used as part of the decision-making process for selecting candidates for admission to medical school. Applicants who learned English as a second language may be at a disadvantage when taking tests in their non-native language. Preliminary research found significant differences between English language learners (ELLs), applicants who learned English after the age of 11 years, and non-ELL examinees on the Verbal Reasoning (VR) sub-test of the MCAT. The purpose of this study was to determine if relationships between VR sub-test scores and measures of medical school performance differed between ELL and non-ELL students. METHODS: Scores on the MCAT VR sub-test and student performance outcomes (grades, examination scores, and markers of distinction and difficulty) were extracted from University of California San Diego School of Medicine admissions files and the Association of American Medical Colleges database for 924 students who matriculated in 1998-2005 (graduation years 2002-2009). Regression models were fitted to determine whether MCAT VR sub-test scores predicted medical school performance similarly for ELLs and non-ELLs. RESULTS: For several outcomes, including pre-clerkship grades, academic distinction, US Medical Licensing Examination Step 2 Clinical Knowledge scores and two clerkship shelf examinations, ELL status significantly affects the ability of the VR score to predict performance. Higher correlations between VR score and medical school performance emerged for non-ELL students than for ELL students for each of these outcomes. CONCLUSIONS: The MCAT VR score should be used with discretion when assessing ELL applicants for admission to medical school.


Assuntos
Teste de Admissão Acadêmica , Avaliação Educacional/métodos , Idioma , Critérios de Admissão Escolar , Estudantes de Medicina/psicologia , California , Humanos , Desenvolvimento da Linguagem , Valor Preditivo dos Testes , Resolução de Problemas , Análise de Regressão , Faculdades de Medicina
12.
J Cell Biol ; 220(11)2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34546351

RESUMO

Atlastin (ATL) GTPases catalyze homotypic membrane fusion of the peripheral endoplasmic reticulum (ER). GTP-hydrolysis-driven conformational changes and membrane tethering are prerequisites for proper membrane fusion. However, the molecular basis for regulation of these processes is poorly understood. Here we establish intrinsic and extrinsic modes of ATL1 regulation that involve the N-terminal hypervariable region (HVR) of ATLs. Crystal structures of ATL1 and ATL3 exhibit the HVR as a distinct, isoform-specific structural feature. Characterizing the functional role of ATL1's HVR uncovered its positive effect on membrane tethering and on ATL1's cellular function. The HVR is post-translationally regulated through phosphorylation-dependent modification. A kinase screen identified candidates that modify the HVR site specifically, corresponding to the modifications on ATL1 detected in cells. This work reveals how the HVR contributes to efficient and potentially regulated activity of ATLs, laying the foundation for the identification of cellular effectors of ATL-mediated membrane processes.


Assuntos
Proteínas de Ligação ao GTP/genética , Proteínas de Membrana/genética , Animais , Linhagem Celular , Retículo Endoplasmático/genética , GTP Fosfo-Hidrolases/genética , Guanosina Trifosfato/genética , Humanos , Hidrólise , Fusão de Membrana/genética , Camundongos , Células NIH 3T3 , Processamento de Proteína Pós-Traducional/genética
13.
J Health Care Poor Underserved ; 32(2): 971-986, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34120988

RESUMO

Studies employing data collected over 15 years ago suggested salutary effects of postbaccalaureate (PB) premedical coursework on medical school class diversity, academic performance, and primary care training. The studies may have limited current applicability given changes in medical school admissions paradigms and population demographics. Using data from interviewees at >1 of 5 California public medical schools between 2011-2013 (N=3805), we examined associations of PB premedical coursework with underrepresented race/ethnicity; academic performance (United States Medical Licensing Examination Step 1 and Step 2 scores, clerkship Honors); and primary care residency. Adjusting for age, sex, and year, PB coursework was associated with underrepresented race/ethnicity, but not after further adjustment for self-designated disadvantage (SDA). PB coursework was not associated with academic performance or primary care residency. Holistic consideration of SDA and UIM status in admissions coupled with robust matriculant support may merit exploration as an alternative to PB coursework for increasing medical school diversity.


Assuntos
Desempenho Acadêmico , Estudantes de Medicina , Etnicidade , Humanos , Atenção Primária à Saúde , Faculdades de Medicina , Estados Unidos
14.
Arthritis Res Ther ; 23(1): 218, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34416923

RESUMO

BACKGROUND: TNF-α-stimulated gene 6 (TSG-6) protein, a TNF-α-responsive hyaladherin, possesses enzymatic activity that can catalyze covalent crosslinks of the polysaccharide hyaluronic acid (HA) to another protein to form heavy chain-hyaluronic acid (HC-HA) complexes in pathological conditions such as osteoarthritis (OA). Here, we examined HA synthase and inflammatory gene expression; synovial fluid HA, TNF-α, and viscosity; and TSG-6-mediated HC-HA complex formation in an equine OA model. The objectives of this study were to (1) evaluate the TNF-α-TSG-6-HC-HA signaling pathway across multiple joint tissues, including synovial membrane, cartilage, and synovial fluid, and (2) determine the impact of OA on synovial fluid composition and biophysical properties. METHODS: HA and inflammatory cytokine concentrations (TNF-α, IL-1ß, CCL2, 3, 5, and 11) were analyzed in synovial fluid from 63 OA and 25 control joints, and HA synthase (HAS1-3), TSG-6, and hyaluronan-degrading enzyme (HYAL2, HEXA) gene expression was measured in synovial membrane and cartilage. HA molecular weight (MW) distributions were determined using agarose gel electrophoresis and solid-state nanopore measurements, and HC-HA complex formation was detected via immunoblotting and immunofluorescence. SEC-MALS was used to evaluate TSG-6-mediated HA crosslinking, and synovial fluid and HA solution viscosities were analyzed using multiple particle-tracking microrheology and microfluidic measurements, respectively. RESULTS: TNF-α concentrations were greater in OA synovial fluid, and TSG6 expression was upregulated in OA synovial membrane and cartilage. TSG-6-mediated HC-HA complex formation was greater in OA synovial fluid and tissues than controls, and HC-HA was localized to both synovial membrane and superficial zone chondrocytes in OA joints. SEC-MALS demonstrated macromolecular aggregation of low MW HA in the presence of TSG-6 and inter-α-inhibitor with concurrent increases in viscosity. CONCLUSIONS: Synovial fluid TNF-α concentrations, synovial membrane and cartilage TSG6 gene expression, and HC-HA complex formation were increased in equine OA. Despite the ability of TSG-6 to induce macromolecular aggregation of low MW HA with resultant increases in the viscosity of low MW HA solutions in vitro, HA concentration was the primary determinant of synovial fluid viscosity rather than HA MW or HC-HA crosslinking. The TNF-α-TSG-6-HC-HA pathway may represent a potential therapeutic target in OA.


Assuntos
Ácido Hialurônico , Osteoartrite , Animais , Condrócitos , Cavalos , Osteoartrite/genética , Líquido Sinovial , Fator de Necrose Tumoral alfa
15.
Clin Orthop Relat Res ; 468(4): 1033-8, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19763722

RESUMO

UNLABELLED: Gastrocnemius recessions have been performed as open or endoscopic procedures. Most of the literature describes the outcomes of these procedures in children with specific neurologic limitations. We report an alternative approach to endoscopic gastrocnemius recessions in neurologically healthy pediatric and adolescent patients whose gastrocnemius equinus could not be corrected nonoperatively. We prospectively followed 23 patients (16 boys, seven girls) who underwent 40 procedures for equinus deformity (n = 22) or osteoarthritis (n = 1). All patients had been directly referred for surgical treatment because all previous nonoperative treatments (stretching, night splints, orthotics, nonsteroidal anti-inflammatory drugs, and physical therapy) had failed. The indications for surgery were patients age 18 years or younger experiencing symptomatic equinus unresponsive to nonoperative care. Pre- and postoperative ankle dorsiflexion were measured. The minimum followup for study inclusion was 1 year (mean, 2.9 years; range, 2-5.1 years). For every patient, dorsiflexion range of motion improved (mean, 15 degrees ; standard deviation, 4 degrees ). No patient had diminished nerve sensation postoperatively. This technique can be used to correct gastrocnemius equinus in otherwise healthy children who have not benefited from prior nonsurgical treatment. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.


Assuntos
Endoscopia/métodos , Pé Equino/cirurgia , Músculo Esquelético/cirurgia , Adolescente , Criança , Pé Equino/complicações , Pé Equino/fisiopatologia , Feminino , Pé Chato/complicações , Pé Chato/fisiopatologia , Pé Chato/cirurgia , Marcha/fisiologia , Humanos , Instabilidade Articular/complicações , Instabilidade Articular/fisiopatologia , Instabilidade Articular/cirurgia , Masculino , Procedimentos Cirúrgicos Minimamente Invasivos , Transtornos dos Movimentos/fisiopatologia , Osteoartrite/complicações , Osteoartrite/fisiopatologia , Osteoartrite/cirurgia , Dor/etiologia , Dor/fisiopatologia , Amplitude de Movimento Articular , Procedimentos de Cirurgia Plástica , Recuperação de Função Fisiológica , Resultado do Tratamento
17.
Methods Mol Biol ; 2159: 93-113, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32529366

RESUMO

A common feature of dynamin-related proteins (DRPs) is their use of guanosine triphosphate (GTP) to control protein dynamics. In the case of the endoplasmic- reticulum- (ER)-resident membrane protein atlastin (ATL), GTP binding and hydrolysis result in membrane fusion of ER tubules and the generation of a branched ER network. In this chapter, we describe two independent methods for dissecting the mechanism underlying nucleotide-dependent quaternary structure and conformational changes of ATL, focusing on size-exclusion chromatography coupled with multi-angle light scattering (SEC-MALS) and Förster resonance energy transfer (FRET), respectively. The high temporal resolution of the FRET-based assays enables the ordering of the molecular events identified in structural and equilibrium-based SEC-MALS studies. In combination, these complementary methods report on the oligomeric states of a system at equilibrium and timing of key steps along the enzyme's catalytic cycle. These methods are broadly applicable to proteins that undergo ligand-induced dimerization and/or conformational changes.


Assuntos
GTP Fosfo-Hidrolases/química , Modelos Moleculares , Conformação Molecular , Nucleotídeos/química , Multimerização Proteica , Cromatografia em Gel , Difusão Dinâmica da Luz , Transferência Ressonante de Energia de Fluorescência , GTP Fosfo-Hidrolases/metabolismo , Humanos , Hidrólise , Cinética , Nucleotídeos/metabolismo , Ligação Proteica , Relação Estrutura-Atividade
18.
J Health Care Poor Underserved ; 31(4S): 208-222, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-35061622

RESUMO

As medical schools seek to address the growing disparity between the socioeconomic makeup of their students and the general population, it is important to understand the academic trajectory of disadvantaged students. We used a locally-developed multicomponent socioeconomic disadvantage (SED) measure and the self-designated disadvantaged (SDA) question ["yes" (+) or "no" (-)] from the American Medical College Application Service application to examine academic performance of students from three disadvantaged categories (high SED/SDA+, high SED/SDA-, and low SED/SDA+); with low SED/SDA-as the reference group across five California schools. Compared with reference, the DA+ subgroups scored lower on USMLE Step 1 and Step 2 Clinical Knowledge examinations and received fewer clerkship Honors. After adjustment for academic metrics and sociodemographic variables, high SED subgroups performed similarly to reference, but performance gaps for low SED/SDA+ students persisted. Medical schools must better understand the institutional and other drivers of academic success in disadvantaged students.

19.
J Med Educ Curric Dev ; 6: 2382120519848048, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31206030

RESUMO

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.

20.
Acad Med ; 94(3): 388-395, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30188370

RESUMO

PURPOSE: To compare the predictive validities of medical school admissions multiple mini-interviews (MMIs) and traditional interviews (TIs). METHOD: This longitudinal observational study of 2011-2013 matriculants to five California public medical schools examined the associations of MMI scores (two schools) and TI scores (three schools) with subsequent academic performance. Regression models adjusted for sociodemographics and undergraduate academic metrics examined associations of standardized mean MMI and TI scores with United States Medical Licensing Examination Step 1 and Step 2 Clinical Knowledge (CK) scores and, for required clerkships, with mean National Board of Medical Examiners Clinical Science subject (shelf) exam score and number of honors grades. RESULTS: Of the 1,460 medical students, 746 (51.1%) interviewed at more than one study school; 579 (39.7%) completed at least one MMI and at least one TI. Neither interview type was associated with Step 1 scores. Higher MMI scores were associated with more clerkship honors grades (adjusted incidence rate ratio [AIRR] 1.28 more [95% CI 1.18, 1.39; P < .01] per SD increase) and higher shelf exam and Step 2 CK scores (adjusted mean 0.73 points higher [95% CI 0.28, 1.18; P < .01] and 1.25 points higher [95% CI 0.09, 2.41; P = .035], respectively, per SD increase). Higher TI scores were associated only with more honors grades (AIRR 1.11 more [95% CI 1.01, 1.20; P = .03] per SD increase). CONCLUSIONS: MMI scores were more strongly associated with subsequent academic performance measures than were TI scores.


Assuntos
Avaliação Educacional/métodos , California , Estágio Clínico , Humanos , Estudos Longitudinais , Modelos Teóricos , Faculdades de Medicina , Estudantes de Medicina
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