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1.
J Telemed Telecare ; : 1357633X231224094, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38254267

RESUMO

INTRODUCTION: Little is known about which conditions seen in primary care are appropriate for video visits. This study evaluated video visits compared to office visits for six conditions: abdominal pain, joint pain, back pain, headache, chest pain, and dizziness. METHODS: Six hundred charts of adult patients from our institution's same-day outpatient clinic were reviewed in this study. Charts for video visits evaluating the aforementioned chief complaints that occurred between August and October 2020 were reviewed and compared with charts for office visits that occurred from August to September 2019. Frequencies of 3-week follow-up visits, Emergency Room visits, imaging, and referrals for office and video visits were measured. Reasons for in-person evaluation for patients seen by video were determined by review of clinician notes. RESULTS: Three-week in-person follow-up was more frequent for patients presenting with chest pain (52% vs 18%, p = 0.0007) and joint pain (24% vs 8%, p = 0.05) after video evaluation, relative to an office evaluation. Three-week in-person follow-up was also more frequent for patients presenting with dizziness (38% vs 28%) and low back pain (24% vs 14%); however, this difference was not statistically significant. Patients presenting with headache and abdominal pain did not have a higher rate of follow-up. DISCUSSION: Based on the frequency of in-person follow-up, this study suggests that video visits are generally adequate for evaluating headache and abdominal pain. Patients with dizziness and chest pain have the highest frequency of in-person and Emergency Room follow-up within 3 weeks when first seen by video compared to other conditions evaluated and may be less suitable for an initial video visit. Institutions can consider these findings when scheduling and providing guidance to patients on what type of visit is most appropriate for their symptoms.

2.
Infect Control Hosp Epidemiol ; 44(12): 2022-2027, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36815249

RESUMO

OBJECTIVE: We investigated a decrease in antibiotic prescribing for respiratory illnesses in 2 academic urgent-care clinics during the coronavirus disease 2019 (COVID-19) pandemic using semistructured clinician interviews. METHODS: We conducted a quality-improvement project from November 2020 to May 2021. We investigated provider antibiotic decision making using a mixed-methods explanatory design including interviews. We analyzed transcripts using a thematic framework approach to identify emergent themes. Our performance measure was antibiotic prescribing rate (APR) for encounters with respiratory diagnosis billing codes. We extracted billing and prescribing data from the electronic medical record and assessed differences using run charts, p charts and generalized linear regression. RESULTS: We observed significant reductions in the APR early during the COVID-19 pandemic (relative risk [RR], 0.20; 95% confidence interval [CI], 0.17-0.25), which was maintained over the study period (P < .001). The average APRs were 14% before the COVID-19 pandemic, 4% during the QI project, and 7% after the project. All providers prescribed less antibiotics for respiratory encounters during COVID-19, but only 25% felt their practice had changed. Themes from provider interviews included changing patient expectations and provider approach to respiratory encounters during COVID-19, the impact of increased telemedicine encounters, and the changing epidemiology of non-COVID-19 respiratory infections. CONCLUSIONS: Our findings suggest that the decrease in APR was likely multifactorial. The average APR decreased significantly during the pandemic. Although the APR was slightly higher after the QI project, it did not reach prepandemic levels. Future studies should explore how these factors, including changing patient expectations, can be leveraged to improve urgent-care antibiotic stewardship.


Assuntos
Gestão de Antimicrobianos , COVID-19 , Infecções Respiratórias , Humanos , Pandemias , Infecções Respiratórias/tratamento farmacológico , Antibacterianos/uso terapêutico , Padrões de Prática Médica , Prescrição Inadequada
3.
JCI Insight ; 7(13)2022 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-35801588

RESUMO

BACKGROUNDProlonged symptoms after SARS-CoV-2 infection are well documented. However, which factors influence development of long-term symptoms, how symptoms vary across ethnic groups, and whether long-term symptoms correlate with biomarkers are points that remain elusive.METHODSAdult SARS-CoV-2 reverse transcription PCR-positive (RT-PCR-positive) patients were recruited at Stanford from March 2020 to February 2021. Study participants were seen for in-person visits at diagnosis and every 1-3 months for up to 1 year after diagnosis; they completed symptom surveys and underwent blood draws and nasal swab collections at each visit.RESULTSOur cohort (n = 617) ranged from asymptomatic to critical COVID-19 infections. In total, 40% of participants reported at least 1 symptom associated with COVID-19 six months after diagnosis. Median time from diagnosis to first resolution of all symptoms was 44 days; median time from diagnosis to sustained symptom resolution with no recurring symptoms for 1 month or longer was 214 days. Anti-nucleocapsid IgG level in the first week after positive RT-PCR test and history of lung disease were associated with time to sustained symptom resolution. COVID-19 disease severity, ethnicity, age, sex, and remdesivir use did not affect time to sustained symptom resolution.CONCLUSIONWe found that all disease severities had a similar risk of developing post-COVID-19 syndrome in an ethnically diverse population. Comorbid lung disease and lower levels of initial IgG response to SARS-CoV-2 nucleocapsid antigen were associated with longer symptom duration.TRIAL REGISTRATIONClinicalTrials.gov, NCT04373148.FUNDINGNIH UL1TR003142 CTSA grant, NIH U54CA260517 grant, NIEHS R21 ES03304901, Sean N Parker Center for Allergy and Asthma Research at Stanford University, Chan Zuckerberg Biohub, Chan Zuckerberg Initiative, Sunshine Foundation, Crown Foundation, and Parker Foundation.


Assuntos
COVID-19 , COVID-19/complicações , Humanos , Imunoglobulina G , SARS-CoV-2 , Síndrome de COVID-19 Pós-Aguda
4.
Cell Rep Med ; 3(7): 100680, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35839768

RESUMO

The biological determinants underlying the range of coronavirus 2019 (COVID-19) clinical manifestations are not fully understood. Here, over 1,400 plasma proteins and 2,600 single-cell immune features comprising cell phenotype, endogenous signaling activity, and signaling responses to inflammatory ligands are cross-sectionally assessed in peripheral blood from 97 patients with mild, moderate, and severe COVID-19 and 40 uninfected patients. Using an integrated computational approach to analyze the combined plasma and single-cell proteomic data, we identify and independently validate a multi-variate model classifying COVID-19 severity (multi-class area under the curve [AUC]training = 0.799, p = 4.2e-6; multi-class AUCvalidation = 0.773, p = 7.7e-6). Examination of informative model features reveals biological signatures of COVID-19 severity, including the dysregulation of JAK/STAT, MAPK/mTOR, and nuclear factor κB (NF-κB) immune signaling networks in addition to recapitulating known hallmarks of COVID-19. These results provide a set of early determinants of COVID-19 severity that may point to therapeutic targets for prevention and/or treatment of COVID-19 progression.


Assuntos
COVID-19 , Humanos , NF-kappa B/metabolismo , Proteômica , SARS-CoV-2 , Transdução de Sinais
5.
BMC Prim Care ; 23(1): 151, 2022 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-35698064

RESUMO

BACKGROUND: Our goals are to quantify the impact on acute care utilization of a specialized COVID-19 clinic with an integrated remote patient monitoring program in an academic medical center and further examine these data with stakeholder perceptions of clinic effectiveness and acceptability. METHODS: A retrospective cohort was drawn from enrolled and unenrolled ambulatory patients who tested positive in May through September 2020 matched on age, presence of comorbidities and other factors. Qualitative semi-structured interviews with patients, frontline clinician, and administrators were analyzed in an inductive-deductive approach to identify key themes. RESULTS: Enrolled patients were more likely to be hospitalized than unenrolled patients (N = 11/137 in enrolled vs 2/126 unenrolled, p = .02), reflecting a higher admittance rate following emergency department (ED) events among the enrolled vs unenrolled, though this was not a significant difference (46% vs 25%, respectively, p = .32). Thirty-eight qualitative interviews conducted June to October 2020 revealed broad stakeholder belief in the clinic's support of appropriate care escalation. Contrary to beliefs the clinic reduced inappropriate care utilization, no difference was seen between enrolled and unenrolled patients who presented to the ED and were not admitted (N = 10/137 in enrolled vs 8/126 unenrolled, p = .76). Administrators and providers described the clinic's integral role in allowing health services to resume in other areas of the health system following an initial lockdown. CONCLUSIONS: Acute care utilization and multi-stakeholder interviews suggest heightened outpatient observation through a specialized COVID-19 clinic and remote patient monitoring program may have contributed to an increase in appropriate acute care utilization. The clinic's role securing safe reopening of health services systemwide was endorsed as a primary, if unmeasured, benefit.


Assuntos
COVID-19 , Instituições de Assistência Ambulatorial , COVID-19/epidemiologia , Controle de Doenças Transmissíveis , Humanos , Monitorização Fisiológica/métodos , Estudos Retrospectivos
6.
J Med Educ Curric Dev ; 9: 23821205221091036, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35372696

RESUMO

Background: In primary care clinics, time constraints and lack of exposure to highly complex cases may limit the breadth and depth of learning for internal medicine residents. To address these issues, we piloted a novel experience for residents to evaluate patients with puzzling symptoms referred by another clinician. Objective: To increase internal medicine residents' exposure to patients with perplexing presentations and foster a team-based approach to solving diagnostically challenging cases. Methods: During the academic year 2020-2021, residents participating in their 2-week primary care "block" rotation were given protected time to evaluate 1-2 patients from the Stanford Consultative Medicine clinic, an internist-led diagnostic second opinion service, and present their patients at the case conference. We assessed the educational value of the program with resident surveys including 5-point Lickert scale and open-ended questions. Results: 21 residents participated in the pilot with a survey response rate of 66.6% (14/21). Both the educational value and overall quality of the experience were rated as 4.8 out of 5 (SD 0.4, range 4-5; 1:"very poor"; 5:"excellent"). Residents learned about new diagnostic tools as well as how to approach complex presentations and diagnostic dilemmas. Residents valued the increased time devoted to patient care, the team-based approach to tackling difficult cases, and the intellectual challenge of these cases. Barriers to implementation include patient case volume, time, and faculty engagement. Conclusions: Evaluation of diagnostically challenging cases in a structured format is a highly valuable experience that offers a framework to enhance outpatient training in internal medicine.

9.
Open Forum Infect Dis ; 9(2): ofab662, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35111874

RESUMO

We compared antibiotic prescribing before and during the -coronavirus disease 2019 (COVID-19) pandemic at 2 academic urgent care clinics and found a sustained decrease in prescribing driven by respiratory encounters and despite transitioning to telemedicine. Antibiotics were rarely prescribed during encounters for COVID-19 or COVID-19 symptoms. COVID-19 revealed opportunities for outpatient stewardship programs.

10.
Am J Med Qual ; 37(3): 221-226, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34310381

RESUMO

Health systems are challenged to provide equitable access to coronavirus disease 2019 (COVID-19) outpatient care during the pandemic. Infected patients may have difficulties accessing regular care and rely on emergency rooms. With the goal to improve system efficiencies and access to care, Stanford launched a designated outpatient COVID-19 "Care and Respiratory Observation of Patients With Novel Coronavirus" clinic in April 2020 in which all adult Stanford patients with newly diagnosed severe acute respiratory syndrome coronavirus 2 were offered follow-up for 2-3 weeks through video, telephone, and in-person encounters. Patients were triaged into risk categories and received home pulse oximeters based on a standardized protocol. Between April 15, 2020, and March 26, 2021, the Care and Respiratory Observation of Patients With Novel Coronavirus clinic enrolled 1317 patients. The clinic provided evaluation of Patients under Investigation, management of acute COVID-19 symptoms, care for COVID-19 patients after hospital discharge, clinical advice, and opportunities for research. The authors share crucial implementation lessons related to team agility, care personalization, and resource optimization.


Assuntos
COVID-19 , Centros Médicos Acadêmicos , Adulto , Instituições de Assistência Ambulatorial , COVID-19/terapia , Humanos , Pandemias , SARS-CoV-2
11.
Allergy ; 77(1): 173-185, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34080210

RESUMO

BACKGROUND: It is unclear whether asthma and its allergic phenotype are risk factors for hospitalization or severe disease from SARS-CoV-2. METHODS: All patients over 28 days old testing positive for SARS-CoV-2 between March 1 and September 30, 2020, were retrospectively identified and characterized through electronic analysis at Stanford. A sub-cohort was followed prospectively to evaluate long-term COVID-19 symptoms. RESULTS: 168,190 patients underwent SARS-CoV-2 testing, and 6,976 (4.15%) tested positive. In a multivariate analysis, asthma was not an independent risk factor for hospitalization (OR 1.12 [95% CI 0.86, 1.45], p = .40). Among SARS-CoV-2-positive asthmatics, allergic asthma lowered the risk of hospitalization and had a protective effect compared with non-allergic asthma (OR 0.52 [0.28, 0.91], p = .026); there was no association between baseline medication use as characterized by GINA and hospitalization risk. Patients with severe COVID-19 disease had lower eosinophil levels during hospitalization compared with patients with mild or asymptomatic disease, independent of asthma status (p = .0014). In a patient sub-cohort followed longitudinally, asthmatics and non-asthmatics had similar time to resolution of COVID-19 symptoms, particularly lower respiratory symptoms. CONCLUSIONS: Asthma is not a risk factor for more severe COVID-19 disease. Allergic asthmatics were half as likely to be hospitalized with COVID-19 compared with non-allergic asthmatics. Lower levels of eosinophil counts (allergic biomarkers) were associated with a more severe COVID-19 disease trajectory. Recovery was similar among asthmatics and non-asthmatics with over 50% of patients reporting ongoing lower respiratory symptoms 3 months post-infection.


Assuntos
Asma , COVID-19 , Asma/diagnóstico , Asma/epidemiologia , Teste para COVID-19 , Humanos , Fenótipo , Estudos Retrospectivos , SARS-CoV-2
12.
Nat Commun ; 12(1): 5417, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34521836

RESUMO

COVID-19 is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. Here we develop three protein arrays to measure IgG autoantibodies associated with connective tissue diseases, anti-cytokine antibodies, and anti-viral antibody responses in serum from 147 hospitalized COVID-19 patients. Autoantibodies are identified in approximately 50% of patients but in less than 15% of healthy controls. When present, autoantibodies largely target autoantigens associated with rare disorders such as myositis, systemic sclerosis and overlap syndromes. A subset of autoantibodies targeting traditional autoantigens or cytokines develop de novo following SARS-CoV-2 infection. Autoantibodies track with longitudinal development of IgG antibodies recognizing SARS-CoV-2 structural proteins and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.


Assuntos
Autoanticorpos/imunologia , COVID-19/imunologia , Imunoglobulina G/imunologia , SARS-CoV-2/imunologia , Idoso , Anticorpos Antinucleares/sangue , Anticorpos Antinucleares/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Autoanticorpos/sangue , Autoantígenos/imunologia , Doenças do Tecido Conjuntivo/imunologia , Citocinas/imunologia , Feminino , Hospitalização , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/patogenicidade , Proteínas Virais/imunologia
13.
medRxiv ; 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33532787

RESUMO

Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. We developed three different protein arrays to measure hallmark IgG autoantibodies associated with Connective Tissue Diseases (CTDs), Anti-Cytokine Antibodies (ACA), and anti-viral antibody responses in 147 hospitalized COVID-19 patients in three different centers. Autoantibodies were identified in approximately 50% of patients, but in <15% of healthy controls. When present, autoantibodies largely targeted autoantigens associated with rare disorders such as myositis, systemic sclerosis and CTD overlap syndromes. Anti-nuclear antibodies (ANA) were observed in ∼25% of patients. Patients with autoantibodies tended to demonstrate one or a few specificities whereas ACA were even more prevalent, and patients often had antibodies to multiple cytokines. Rare patients were identified with IgG antibodies against angiotensin converting enzyme-2 (ACE-2). A subset of autoantibodies and ACA developed de novo following SARS-CoV-2 infection while others were transient. Autoantibodies tracked with longitudinal development of IgG antibodies that recognized SARS-CoV-2 structural proteins such as S1, S2, M, N and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. COVID-19 patients with one or more autoantibodies tended to have higher levels of antibodies against SARS-CoV-2 Nonstructural Protein 1 (NSP1) and Methyltransferase (ME). We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.

14.
bioRxiv ; 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33594362

RESUMO

The biological determinants of the wide spectrum of COVID-19 clinical manifestations are not fully understood. Here, over 1400 plasma proteins and 2600 single-cell immune features comprising cell phenotype, basal signaling activity, and signaling responses to inflammatory ligands were assessed in peripheral blood from patients with mild, moderate, and severe COVID-19, at the time of diagnosis. Using an integrated computational approach to analyze the combined plasma and single-cell proteomic data, we identified and independently validated a multivariate model classifying COVID-19 severity (multi-class AUCtraining = 0.799, p-value = 4.2e-6; multi-class AUCvalidation = 0.773, p-value = 7.7e-6). Features of this high-dimensional model recapitulated recent COVID-19 related observations of immune perturbations, and revealed novel biological signatures of severity, including the mobilization of elements of the renin-angiotensin system and primary hemostasis, as well as dysregulation of JAK/STAT, MAPK/mTOR, and NF-κB immune signaling networks. These results provide a set of early determinants of COVID-19 severity that may point to therapeutic targets for the prevention of COVID-19 progression.

15.
Ann Intern Med ; 173(7): 527-535, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32628536

RESUMO

BACKGROUND: The coronavirus disease 2019 pandemic spurred health systems across the world to quickly shift from in-person visits to safer video visits. OBJECTIVE: To seek stakeholder perspectives on video visits' acceptability and effect 3 weeks after near-total transition to video visits. DESIGN: Semistructured qualitative interviews. SETTING: 6 Stanford general primary care and express care clinics at 6 northern California sites, with 81 providers, 123 staff, and 97 614 patient visits in 2019. PARTICIPANTS: 53 program participants (overlapping roles as medical providers [n = 20], medical assistants [n = 16], nurses [n = 4], technologists [n = 4], and administrators [n = 13]) were interviewed about video visit transition and challenges. INTERVENTION: In 3 weeks, express care and primary care video visits increased from less than 10% to greater than 80% and from less than 10% to greater than 75%, respectively. New video visit providers received video visit training and care quality feedback. New system workflows were created to accommodate the new visit method. MEASUREMENTS: 9 faculty, trained in qualitative research methods, conducted 53 stakeholder interviews in 4 days using purposeful (administrators and technologists) and convenience (medical assistant, nurses, and providers) sampling. A rapid qualitative analytic approach for thematic analysis was used. RESULTS: The analysis revealed 12 themes, including Pandemic as Catalyst; Joy in Medicine; Safety in Medicine; Slipping Through the Cracks; My Role, Redefined; and The New Normal. Themes were analyzed using the RE-AIM (reach, effectiveness, adoption, implementation, and maintenance) framework to identify critical issues for continued program utilization. LIMITATIONS: Evaluation was done immediately after deployment. Although viewpoints may have evolved later, immediate evaluation allowed for prompt program changes and identified broader issues to address for program sustainability. CONCLUSION: After pandemic-related systems transformation at Stanford, critical issues to sustain video visit long-term viability were identified. Specifically, technology ease of use must improve and support multiparty videoconferencing. Providers should be able to care for their patients, regardless of geography. Providers need decision-making support with virtual examination training and home-based patient diagnostics. Finally, ongoing video visit reimbursement should be commensurate with value to the patients' health and well-being. PRIMARY FUNDING SOURCE: Stanford Department of Medicine and Stanford Health Care.


Assuntos
Atitude do Pessoal de Saúde , Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Atenção Primária à Saúde/métodos , Telemedicina/métodos , Adulto , Betacoronavirus , COVID-19 , California/epidemiologia , Feminino , Humanos , Masculino , Pandemias , Pesquisa Qualitativa , SARS-CoV-2
16.
Pol Arch Intern Med ; 129(12): 907-912, 2019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31777402

RESUMO

At its most fundamental level, the clinical encounter between a patient and their doctor seeks to solve a mystery. Clinicians uncover clues through the history, physical examination, and ancillary tests to arrive at a diagnosis and develop a management plan. Despite advances in technology, the majority of clinical diagnoses are still reached through the history and physical examination without the use of laboratory and imaging tests. However, in the modern American hospital, clinicians spend as little as 12% of their time in direct contact with patients and their families. This has led to a decline in clinical examination skills and contributes to diagnostic error. There is a growing movement to return clinicians and trainees back to the bedside. In 2017, we formed the Society of Bedside Medicine to encourage innovation, education, and research on the role of the clinical encounter in 21st century medicine. Over the last 3 years, we have embraced the following 6 strategies to reinvigorate the practice of the clinical examination: 1) be present with the patient; 2) practice an evidence­based approach to the physical exam; 3) create opportunities for intentional practice of the physical exam; 4) recognize the power of the physical examination beyond diagnosis; 5) use point­of­care technology to aid in diagnosis and reinforce skills; and 6) seek and provide specific feedback on physical examination skills. By employing these strategies in both teaching and practice, clinicians can maximize the value of time spent with patients and renew the importance of the clinical examination in 21st century practice.


Assuntos
Técnicas e Procedimentos Diagnósticos/normas , Técnicas e Procedimentos Diagnósticos/tendências , Anamnese/normas , Exame Físico/normas , Exame Físico/tendências , Guias de Prática Clínica como Assunto , Previsões , Humanos , Polônia
17.
Med Clin North Am ; 102(3): 465-473, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29650068

RESUMO

The physical examination in the outpatient setting is a valuable tool. Even in settings where there is lack of evidence, such as the annual physical examination of an asymptomatic adult, the physical examination is beneficial for the physician-patient relationship. When a patient has specific symptoms, the physical examination-in addition to a thorough history-can help narrow down, or in many cases establish, a diagnosis. In a time where imaging and laboratory tests are easily available, but are expensive and can be invasive, a skilled physical examination remains an important component of patient evaluation.


Assuntos
Assistência Ambulatorial/métodos , Exame Físico/métodos , Assistência Ambulatorial/normas , Diagnóstico Diferencial , Humanos , Exame Físico/normas
18.
Am J Med ; 129(8): 792-5, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26972793

RESUMO

In today's hospital and clinic environment, the obstacles to bedside teaching for both faculty and trainees are considerable. As electronic health record systems become increasingly prevalent, trainees are spending more time performing patient care tasks from computer workstations, limiting opportunities to learn at the bedside. Physical examination skills rarely are emphasized, and low confidence levels, especially in junior faculty, pose additional barriers to teaching the bedside examination.


Assuntos
Competência Clínica , Medicina Clínica/educação , Educação Médica/métodos , Exame Físico , Ensino , Registros Eletrônicos de Saúde , Humanos , Relações Médico-Paciente , Sistemas Automatizados de Assistência Junto ao Leito
19.
PLoS Genet ; 4(1): e10, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18208333

RESUMO

Telomerase serves a critical role in stem cell function and tissue homeostasis. This role depends on its ability to synthesize telomere repeats in a manner dependent on the reverse transcriptase (RT) function of its protein component telomerase RT (TERT), as well as on a novel pathway whose mechanism is poorly understood. Here, we use a TERT mutant lacking RT function (TERT(ci)) to study the mechanism of TERT action in mammalian skin, an ideal tissue for studying progenitor cell biology. We show that TERT(ci) retains the full activities of wild-type TERT in enhancing keratinocyte proliferation in skin and in activating resting hair follicle stem cells, which triggers initiation of a new hair follicle growth phase and promotes hair synthesis. To understand the nature of this RT-independent function for TERT, we studied the genome-wide transcriptional response to acute changes in TERT levels in mouse skin. We find that TERT facilitates activation of progenitor cells in the skin and hair follicle by triggering a rapid change in gene expression that significantly overlaps the program controlling natural hair follicle cycling in wild-type mice. Statistical comparisons to other microarray gene sets using pattern-matching algorithms revealed that the TERT transcriptional response strongly resembles those mediated by Myc and Wnt, two proteins intimately associated with stem cell function and cancer. These data show that TERT controls tissue progenitor cells via transcriptional regulation of a developmental program converging on the Myc and Wnt pathways.


Assuntos
Células Epiteliais/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Proto-Oncogênicas c-myc/genética , Telomerase/metabolismo , Proteínas Wnt/genética , Algoritmos , Animais , Biópsia , Proliferação de Células , Procedimentos Cirúrgicos Dermatológicos , Perfilação da Expressão Gênica , Cabelo/metabolismo , Folículo Piloso/citologia , Folículo Piloso/metabolismo , Imuno-Histoquímica , Queratinócitos/fisiologia , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Mutação , RNA Mensageiro/metabolismo , Pele/citologia , Pele/enzimologia , Pele/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Telomerase/genética , Transcrição Gênica
20.
Nature ; 436(7053): 1048-52, 2005 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-16107853

RESUMO

TERT, the protein component of telomerase, serves to maintain telomere function through the de novo addition of telomere repeats to chromosome ends, and is reactivated in 90% of human cancers. In normal tissues, TERT is expressed in stem cells and in progenitor cells, but its role in these compartments is not fully understood. Here we show that conditional transgenic induction of TERT in mouse skin epithelium causes a rapid transition from telogen (the resting phase of the hair follicle cycle) to anagen (the active phase), thereby facilitating robust hair growth. TERT overexpression promotes this developmental transition by causing proliferation of quiescent, multipotent stem cells in the hair follicle bulge region. This new function for TERT does not require the telomerase RNA component, which encodes the template for telomere addition, and therefore operates through a mechanism independent of its activity in synthesizing telomere repeats. These data indicate that, in addition to its established role in extending telomeres, TERT can promote proliferation of resting stem cells through a non-canonical pathway.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Folículo Piloso/citologia , Células-Tronco/citologia , Telomerase/genética , Telomerase/metabolismo , Animais , Bromodesoxiuridina/metabolismo , Proliferação de Células , Proteínas de Ligação a DNA/deficiência , Indução Enzimática , Folículo Piloso/enzimologia , Camundongos , Camundongos Transgênicos , RNA/genética , Células-Tronco/enzimologia , Telomerase/deficiência , Transgenes/genética
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