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1.
J Telemed Telecare ; 29(8): 607-612, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33975506

RESUMO

INTRODUCTION: The need to rapidly implement telehealth at large scale during the COVID-19 pandemic led to many patients using telehealth for the first time. We assessed the effect of structured pre-visit preparatory telephone calls on success of telehealth visits and examined risk factors for unsuccessful visits. METHODS: A retrospective cohort study was carried out of 45,803 adult patients scheduled for a total of 64,447 telehealth appointments between March and July 2020 at an academic medical center. A subset of patients received a structured pre-visit phone call. Demographic factors and inclusion of a pre-visit call were analysed by logistic regression. Primary outcomes were non-completion of any visit and completion of phone-only versus audio-visual telehealth visits. RESULTS: A pre-visit telephone call to a subset of patients significantly increased the likelihood of a successful telehealth visit (OR 0.54; 95% CI: 0.48-0.60). Patients aged 18-30 years, those with non-commercial insurance or those of Black race were more likely to have incomplete visits. Compared to age 18-30, increasing age increased likelihood of a failed video visit: 31-50 years (OR 1.31; 95% CI: 1.13-1.51), 51-70 years (OR 2.98; 2.60-3.42) and >70 years (OR 4.16; 3.58-4.82). Those with non-commercial insurance and those of Black race (OR 1.8; 95% CI 1.67-1.92) were more likely to have a failed video visit. DISCUSSION: A structured pre-call to patients improved the likelihood of a successful video visit during widespread adoption of telehealth. Structured pre-calls to patients may be an important tool to help reduce gaps in utilization among groups.


Assuntos
Visita a Consultório Médico , Educação de Pacientes como Assunto , Telemedicina , Humanos , Telefone , COVID-19/epidemiologia , Estudos Retrospectivos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais
3.
Inflamm Bowel Dis ; 28(3): 358-363, 2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33769496

RESUMO

BACKGROUND: This study evaluated synchronous audiovisual telehealth and audio-only visits for patients with inflammatory bowel disease (IBD) to determine frequency of successful telehealth visits and determine what factors increase the likelihood of completion. METHODS: Data were collected from March to July 2020 in a tertiary care adult IBD clinic that was transitioned to a fully telehealth model. A protocol for telehealth was implemented. A retrospective analysis was performed using electronic medical record (EMR) data. All patients were scheduled for video telehealth. If this failed, providers attempted to conduct the visit as audio only. RESULTS: Between March and July 2020, 2571 telehealth visits were scheduled for adult patients with IBD. Of these, 2498 (99%) were successfully completed by video or phone. Sixty percent were female, and the median age was 41 years. Eighty six percent of the population was white, 8% black, 2% other, and 4% were missing. Seventy-five percent had commercial insurance, 15% had Medicare, 5% had Medicaid, and 5% had other insurance. No significant factors were found for an attempted but completely failed visit. Using a multivariate logistic regression model, increasing age (odds ratio, 1.80; 95% CI, 1.55-2.08; P < 0.05), noncommercial insurance status (odds ratio, 1.89; 95% CI, 1.61-2.21; P < 0.05), and black race (odds ratio, 2.07; 95% CI, 1.38-3.08; P < 0.05) increased the likelihood of a video encounter failure. CONCLUSIONS: There is a high success rate for telehealth within an IBD population with defined clinic protocols. Certain patient characteristics such as age, race, and health insurance type increase the risk of failure of a video visit.


Assuntos
COVID-19 , Doenças Inflamatórias Intestinais , Telemedicina , Adulto , Idoso , Demografia , Feminino , Humanos , Doenças Inflamatórias Intestinais/epidemiologia , Doenças Inflamatórias Intestinais/terapia , Medicare , Estudos Retrospectivos , Estados Unidos/epidemiologia
4.
Endocr Pract ; 27(10): 1017-1021, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34147691

RESUMO

OBJECTIVE: Telehealth (TH) use in endocrinology was limited before the COVID-19 pandemic but will remain a major modality of care postpandemic. Reimbursement policies have been limited historically due to concerns of overutilization of visits and testing. Additionally, there is limited literature on endocrinology care delivered via TH for conditions other than diabetes. We assess real-world TH use for endocrinology in a prepandemic environment with the hypothesis that TH would not increase the utilization of total visits or related ancillary testing services compared with conventional (CVL) face-to-face office visits. METHODS: A single-institution retrospective cohort study assessing the prepandemic use of TH in endocrinology, consisting of 75 patients seen via TH and 225 patients seen in CVL visits. For most patients, TH was conducted via a clinic-to-clinic model. Outcomes measured were total endocrine visit frequency and frequency of related laboratory and radiology testing per patient, hemoglobin A1C, microalbumin, low-density lipoprotein, thyroid-stimulating hormone, thyroglobulin, and thyroid ultrasounds. RESULTS: For all endocrine visits, TH patients had a median of 0.24 (interquartile range, 0.015-0.36) visits per month. CVL patients had a median of 0.20 visits per month (interquartile range, 0.11-0.37). Total visits per month did not vary significantly between groups (P = .051). Hemoglobin A1C outcomes were equivalent and there was no increase in ancillary laboratory testing for the TH group. CONCLUSION: Our observations demonstrate that, in a prepandemic health care setting, TH visits can provide equivalent care for endocrinology patients, without increasing utilization of total visits or ancillary services.


Assuntos
COVID-19 , Telemedicina , Humanos , Pandemias , Estudos Retrospectivos , SARS-CoV-2
5.
J Clin Endocrinol Metab ; 106(1): e377-e381, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33205818

RESUMO

The coronavirus disease pandemic has created opportunities for innovation in diabetes care that were not possible before. From the lens of this "new normal" state, we have an opportunity to rapidly implement, test, and iterate models of diabetes care to achieve the quadruple aim of improving medical outcomes, patient experience, provider satisfaction, and reducing costs. In this perspective, we discuss several innovative diabetes models of care which promote collaborative care models and improve access to high-quality specialty diabetes care. We discuss ongoing threats to diabetes care innovation, and offer practical solutions to foster evolution and sustain current strides made during the pandemic.


Assuntos
COVID-19/epidemiologia , Diabetes Mellitus/terapia , SARS-CoV-2 , Humanos , Equipe de Assistência ao Paciente , Farmacêuticos , Encaminhamento e Consulta , Telemedicina
6.
Clin Diabetes ; 38(3): 295-299, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32699480

RESUMO

Quality Improvement Success Stories are published by the American Diabetes Association in collaboration with the American College of Physicians and the National Diabetes Education Program. This series is intended to highlight best practices and strategies from programs and clinics that have successfully improved the quality of care for people with diabetes or related conditions. Each article in the series is reviewed and follows a standard format developed by the editors of Clinical Diabetes. The following article describes the design and implementation of a pharmacist-led program to improve rates of statin use among appropriate patients in high-risk populations.

8.
J Clin Endocrinol Metab ; 105(8)2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32525973

RESUMO

CONTEXT: The potential for endocrine care via telemedicine has been recognized since the early 2000s when clinical outcome data demonstrated improvements in glycemic control with telemedicine. The widespread use of telemedicine during the COVID-19 pandemic has pushed telemedicine beyond diabetes care and into clinical areas with a paucity of published data. The evaluation and treatment of thyrotoxicosis heavily relies on laboratory assessment and imaging with physical exam playing a role to help differentiate the etiology and assess the severity of thyrotoxicosis. CASE DESCRIPTION: We describe a patient presenting for evaluation of new thyrotoxicosis via telemedicine, and describe modifications to consider for thorough, safe evaluation via telemedicine. CONCLUSION: Telemedicine may be an ideal way to assess and treat patients with thyrotoxicosis who are not able to physically attend a visit with an endocrinologist but still have access to a laboratory for blood draws. Potential challenges include access to imaging and high-volume surgeons if needed. Clinical and economic outcomes of telemedicine care of thyrotoxicosis should be studied so that standards of care for endocrine telemedicine can be established.


Assuntos
Infecções por Coronavirus/prevenção & controle , Endocrinologia/métodos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Avaliação de Sintomas/métodos , Telemedicina/métodos , Tireotoxicose/diagnóstico , Adulto , Betacoronavirus , COVID-19 , Feminino , Humanos , SARS-CoV-2
9.
J Clin Med ; 5(11)2016 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-27869655

RESUMO

Telemedicine can connect specialist health care providers with patients in remote and underserved areas. It is especially relevant in diabetes care, where a proliferation of treatment options has added further complexity to the care of an already complex, highly prevalent disease. Recent developments in health reform encourage delivery systems to use team-based models and engage patients in shared decision-making (SDM), where patients and providers together make health care decisions that are tailored to the specific characteristics and values of the patient. The goal of this project was to design, integrate, and evaluate a team-based, SDM approach delivered to patients with diabetes in a rural community, building upon the previously established telemedicine for reach, education, access, and treatment (TREAT) model. Patients in this feasibility study demonstrated improvement in hemoglobin A1c values, and reported better understanding of diabetes. Providers reported the SDM aids increased cohesion among team members (including patients) and facilitated patient education and behavioral goal setting. This project demonstrated that SDM could be integrated into the workflow of a telemedicine team visit with good provider and patient satisfaction.

10.
J Clin Endocrinol Metab ; 97(6): 2019-26, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22466346

RESUMO

OBJECTIVE: We examined the effect of hospital admissions on the medical treatment of poorly controlled diabetes mellitus among Veterans Affairs (VA) patients. RESEARCH DESIGN AND METHODS: This retrospective cohort study included male patients admitted to one of three VA hospitals from July 1, 2002, to August 31, 2009, who were receiving medication therapy for diabetes with hemoglobin A1c (HgbA1c) greater than 8.0%. The primary outcome was a change in preadmission and outpatient prescriptions for diabetes at hospital discharge. Covariates for multivariable logistic regression analysis of the primary outcome were defined a priori and retrieved from the electronic health record. RESULTS: Of 2025 admissions for 1359 patients, 454 had some change in diabetes medications at discharge (rate of change 22.4%). In an adjusted analysis, higher preadmission HgbA1c [odds ratio (OR) 1.12 per 1.0 U increase; 95% confidence interval (CI) 1.12-1.05; P < 0.001], higher mean blood glucose during admission (OR 1.07 per 10 mg/dl increase; 95% CI 1.05-1.10; P < 0.0001), occurrence of inpatient hypoglycemia (blood glucose < 50 mg/dl; OR 1.82, 95% CI 1.32-2.51, P < 0.001), and inpatient basal insulin therapy (OR 1.71; 95% CI 1.25-2.35; P < 0.001) were associated with higher odds of change in therapy. A total of 656 admissions (32%) demonstrated aggregate clinical inertia with no change in therapy, no documentation of HgbA1c within 60 d of discharge, and no follow-up appointment within 30 d of discharge. CONCLUSIONS: In this multicenter, retrospective study of patients with poorly controlled diabetes and at least one hospitalization, less than a quarter received a change in outpatient diabetes therapy upon discharge, suggesting widespread clinical inertia. Nearly one third had no change in therapy or subsequent follow-up scheduled.


Assuntos
Assistência Ambulatorial/estatística & dados numéricos , Continuidade da Assistência ao Paciente/estatística & dados numéricos , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/epidemiologia , Insulina/uso terapêutico , Alta do Paciente/estatística & dados numéricos , Idoso , Assistência Ambulatorial/normas , Estudos de Coortes , Continuidade da Assistência ao Paciente/normas , Diabetes Mellitus Tipo 1/metabolismo , Seguimentos , Hemoglobinas Glicadas/metabolismo , Hospitalização/estatística & dados numéricos , Hospitais de Veteranos/normas , Hospitais de Veteranos/estatística & dados numéricos , Humanos , Hipoglicemiantes/uso terapêutico , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Avaliação de Processos e Resultados em Cuidados de Saúde , Alta do Paciente/normas , Estudos Retrospectivos
11.
Blood ; 119(10): 2417-21, 2012 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-22262764

RESUMO

Chronic inflammation and decreased frequency of regulatory T cells (Tregs) in visceral adipose tissue contribute to the propagation of insulin resistance to diabetes mellitus. We tested the hypothesis that new-onset posttransplantation diabetes mellitus (PTDM) is associated with measurable changes in Treg subsets after allogeneic hematopoietic stem cell transplantation (HSCT). PTDM before day 100 and Treg phenotype at engraftment were determined in 36 HSCT recipients without preceding history of diabetes mellitus. Among patients with new-onset PTDM (N = 24), the frequency of circulating CLA(+) (skin-homing) Tregs was decreased (1.53% vs 3.99%; P = .002) and the percentage of α(4)ß(7)(+) (gut-homing) Tregs was increased (17.9% vs 10.7%; P = .048). In multivariate analysis, patients with PTDM continued to demonstrate elevated ratios of α(4)ß(7)(+) Tregs to CLA(+) Tregs (odds ratio, 18.1; P = .020). PTDM is associated with altered immune regulation after HSCT and could represent a target to modulate alloreactivity.


Assuntos
Diabetes Mellitus/sangue , Transplante de Células-Tronco Hematopoéticas/métodos , Complicações Pós-Operatórias/sangue , Linfócitos T Reguladores/metabolismo , Adulto , Idoso , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/etiologia , Feminino , Citometria de Fluxo , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/etiologia , Valor Preditivo dos Testes , Prognóstico , Linfócitos T Reguladores/citologia , Fatores de Tempo , Transplante Homólogo , Adulto Jovem
12.
Int J Med Inform ; 81(3): 143-56, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22244191

RESUMO

OBJECTIVE: The majority of clinical symptoms are stored as free text in the clinical record, and this information can inform clinical decision support and automated surveillance efforts if it can be accurately processed into computer interpretable data. METHODS: We developed rule-based algorithms and evaluated a natural language processing (NLP) system for infectious symptom detection using clinical narratives. Training (60) and testing (444) documents were randomly selected from VA emergency department, urgent care, and primary care records. Each document was processed with NLP and independently manually reviewed by two clinicians with adjudication by referee. Infectious symptom detection rules were developed in the training set using keywords and SNOMED-CT concepts, and subsequently evaluated using the testing set. RESULTS: Overall symptom detection performance was measured with a precision of 0.91, a recall of 0.84, and an F measure of 0.87. Overall symptom detection with assertion performance was measured with a precision of 0.67, a recall of 0.62, and an F measure of 0.64. Among those instances in which the automated system matched the reference set determination for symptom, the system correctly detected 84.7% of positive assertions, 75.1% of negative assertions, and 0.7% of uncertain assertions. CONCLUSION: This work demonstrates how processed text could enable detection of non-specific symptom clusters for use in automated surveillance activities.


Assuntos
Doenças Transmissíveis/diagnóstico , Sistemas de Apoio a Decisões Clínicas/organização & administração , Diagnóstico por Computador , Serviço Hospitalar de Emergência , Infecções/diagnóstico , Sistemas Computadorizados de Registros Médicos/organização & administração , Algoritmos , Hospitais de Veteranos , Humanos , Vigilância da População , Atenção Primária à Saúde
13.
Blood ; 117(11): 3002-9, 2011 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-21193694

RESUMO

More than 25,000 allogeneic hematopoietic stem cell transplantations (allo-HCTs) are expected to be performed worldwide in 2010, a number that has been increasing yearly. With broadening indications, more options for allo-HCT, and improvement in survival, by 2020 there may be up to half a million long-term survivors after allo-HCT worldwide. These patients have increased risks for various late complications, which can cause morbidity and mortality. Most long-term survivors return to the care of their local hematologists/oncologists or primary care physicians, who may not be familiar with specialized monitoring recommendations for this patient population. The purpose of this article is to describe practical approaches to screening for and managing these late effects, with the goal of reducing preventable morbidity and mortality associated with allo-HCT.


Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Sobreviventes , Adulto , Humanos , Fatores de Tempo , Transplante Homólogo/efeitos adversos , Vacinação
14.
Biol Blood Marrow Transplant ; 17(1): 86-92, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20561594

RESUMO

Posttransplantation diabetes mellitus (PTDM) is a frequent complication after allogeneic stem cell transplantation (allo-SCT), important for its negative impact on cardiovascular health. Risk factors for PTDM are not well defined. We conducted a prospective study to investigate the risk factors and incidence for PTDM in the first 100 days after allo-SCT. A total of 84 patients completed the study, 60% of whom developed PTDM. In a multivariate logistic regression model, pretransplantation c-peptide level (>3.6 ng/mL; odds ratio [OR], 5.9; 95% confidence interval [CI], 1.77-20.22; P = .004), unrelated donor allo-SCT (OR, 4.3; 95% CI, 1.34-14.2; P = .014), and peak steroid dose >1 mg/kg/day (OR, 5.09; 95% CI, 1.19-23.2; P = .035) were identified as independent predictors of PTDM. In addition, overall survival (OS) was inferior in patients with PTDM compared with those without PTDM (mean survival, 2.26 years vs 2.7 years; P = .021). Pretransplantation c-peptide level greater than the cohort median (>3.6 ng/mL) also was associated with inferior OS (mean, 1.7 years vs 2.9 years; P = .012). In a multivariate Cox proportional hazards model, high-risk disease (hazard ratio [HR], 2.34; 95% CI, 1.09-5.28; P = .029) and pretransplantation c-peptide level >3.6 ng/mL (HR, 1.05; 95% CI, 1.01-1.09; P = .013) were independent predictors of OS when adjusted for systemic steroids and regimen intensity. We suspect that diabetes mellitus in the immediate posttransplantation period may be mediated via an inflammatory pathway that contributes to insulin resistance in the host adipose tissue. Our study is the first to report the risk factors of early PTDM in patients undergoing allo-SCT and identifies pretransplantation c-peptide as an independent predictor of diabetes and survival.


Assuntos
Peptídeo C/sangue , Diabetes Mellitus/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Valor Preditivo dos Testes , Adulto , Diabetes Mellitus/mortalidade , Feminino , Transplante de Células-Tronco Hematopoéticas/mortalidade , Humanos , Inflamação , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Taxa de Sobrevida , Fatores de Tempo , Transplante Homólogo
15.
Endocr Pract ; 16(4): 699-706, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20439241

RESUMO

OBJECTIVE: To review the current literature on posttransplant diabetes mellitus after hematopoietic stem cell transplantation, including its epidemiologic features, transplant-related risk factors, and treatment. METHODS: A literature search was conducted in PubMed for articles on diabetes mellitus after hematopoietic stem cell transplantation and effects of immunosuppressants on glucose metabolism. RESULTS: Within 2 years after hematopoietic stem cell transplantation, up to 30% of patients may have diabetes. Although some of these cases resolve, the rates of diabetes and metabolic syndrome remain elevated in comparison with those in the nontransplant patient population during long-term follow-up. Traditional risk factors for diabetes as well as features related to the transplantation process, including immunosuppressive medications, are associated with posttransplant diabetes. Cardiovascular risk also appears to be increased in this population. Limited data are available on hypoglycemic agents for posttransplant diabetes; thus, treatment decisions must be based on safety, efficacy, and tolerability, with consideration of each patient's transplant-related medications and comorbidities. CONCLUSION: Treatment of diabetes mellitus in patients who have undergone hematopoietic stem cell transplantation necessitates attention to the posttransplant medication regimen and clinical course. Although no guidelines specific to treatment of posttransplant diabetes in this patient population currently exist, treatment to goals similar to those for nontransplant patients with diabetes should be considered in an attempt to help reduce long-term morbidity and mortality.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/epidemiologia , Transplante de Células-Tronco Hematopoéticas , Imunossupressores/efeitos adversos , Adolescente , Adulto , Doenças Cardiovasculares/epidemiologia , Criança , Contraindicações , Diabetes Mellitus/metabolismo , Diabetes Mellitus/terapia , Dislipidemias/epidemiologia , Glucose/metabolismo , Doença Enxerto-Hospedeiro/tratamento farmacológico , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/uso terapêutico , Imunossupressores/uso terapêutico , Síndrome Metabólica/epidemiologia , Prevalência , Fatores de Risco
16.
Blood ; 116(8): 1197-204, 2010 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-20439623

RESUMO

Currently, approximately 15,000 to 20,000 patients undergo allogeneic hematopoietic stem cell transplantation (HSCT) annually throughout the world, with the number of long-term survivors increasing rapidly. In long-term follow-up after transplantation, the focus of care moves beyond cure of the original disease to the identification and treatment of late effects after HSCT. One of the more serious complications is therapy-related cardiovascular disease. Long-term survivors after HSCT probably have an increased risk of premature cardiovascular events. Cardiovascular complications related to dyslipidemia and other risk factors account for a significant proportion of late nonrelapse morbidity and mortality. This review addresses the risk and causes of dyslipidemia and impact on cardiovascular complications after HSCT. Immunosuppressive therapy, chronic graft-versus-host disease, and other long-term complications influence the management of dyslipidemia. There are currently no established guidelines for evaluation and management of dyslipidemia in HSCT patients; in this review, we have summarized our suggested approach in the HSCT population.


Assuntos
Doenças Cardiovasculares/etiologia , Dislipidemias/etiologia , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Doenças Cardiovasculares/patologia , Dislipidemias/patologia , Doença Enxerto-Hospedeiro/patologia , Humanos , Transplante Homólogo
17.
Expert Opin Drug Metab Toxicol ; 6(2): 225-35, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20055691

RESUMO

IMPORTANCE OF THE FIELD: Type 2 diabetes mellitus (T2DM) is increasingly prevalent throughout the world; controlling glycemia is an important part of preventing serious complications of diabetes. Sulfonylureas have been used in the treatment of type 2 diabetes for many years. AREAS COVERED IN THIS REVIEW: This article reviews the pharmacological and clinical aspects of glimepiride, a second-generation sulfonylurea. Literature search was conducted in PubMed, and articles selected for relevance to pharmacology or clinical efficacy data from 1994 to 2009, with older references sought as indicated. WHAT THE READER WILL GAIN: Pharmacology of glimepiride, data regarding clinical efficacy, key comparisons to other agents and emerging concepts related to glimepiride are discussed. TAKE HOME MESSAGE: Therapy with glimepiride improves the relative insulin secretory deficit found in T2DM, has antihyperglycemic efficacy equal to other secretagogues with reduced potential for hypoglycemia and may have additional actions contributing to glycemic control in T2DM.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Compostos de Sulfonilureia/uso terapêutico , Humanos , Hipoglicemiantes/farmacologia , Compostos de Sulfonilureia/farmacologia
18.
Genetics ; 160(1): 257-69, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11805061

RESUMO

The brown(Dominant) (bw(D)) allele contains a large insertion of heterochromatin leading to the trans-inactivation of the wild-type allele in bw(D)/bw(+) heterozygous flies. This silencing is correlated with the localization of bw(+) to a region of the interphase nucleus containing centric heterochromatin. We have used a series of transgene constructs inserted in the vicinity of the bw locus to demarcate both the extent of bw(D) influence along the chromosome and the relative sensitivities of various genes. Examples of regulatory regions that are highly sensitive, moderately sensitive, and insensitive were found. Additionally, by using the same transgene at increasing distances from the bw(D) insertion site in trans we were able to determine the range of influence of the heterochromatic neighborhood in terms of chromosomal distance. When the transgene was farther away from bw, there was, indeed, a tendency for it to be less trans-inactivated. However, insertion site also influenced silencing: a gene 86 kb away was trans-inactivated, while the same transgene 45 kb away was not. Thus location, distance, and gene-specific differences all influence susceptibility to trans-silencing near a heterochromatic neighborhood. These results have important implications for the ability of nuclear positioning to influence the expression of large blocks of a chromosome.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Drosophila melanogaster/genética , Inativação Gênica , Genes de Insetos , Heterocromatina/fisiologia , Animais , Animais Geneticamente Modificados , Caspases , Elementos de DNA Transponíveis , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Feminino , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico/genética , Proteínas de Insetos/genética , Óperon Lac , Masculino , Regiões Promotoras Genéticas , Transgenes
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