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1.
Arch Clin Neuropsychol ; 39(1): 24-34, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-37530515

RESUMO

OBJECTIVES: To describe the characteristics of patients receiving a clinical referral for neuropsychological evaluation in two Huntington's Disease Society of America Centers of Excellence (HDSA COE). In this exploratory pilot study, we used an empirically supported clinical neuropsychological battery to assess differences in cognitive performance between premanifest and manifest HD patient groups (compared with each other and normative expectations). METHOD: Clinical data from 76 adult genetically confirmed patients referred for neuropsychological evaluations was retrospectively collected from two HDSA COEs. ANOVA and Chi-square tests were used to compare variables between pre-manifest (n = 14) and manifest (n = 62) groups for demographic, cognitive, neuropsychiatric, and disease severity variables. RESULTS: Our clinics serviced a disproportionate number of motor manifest patients. Six measures were excluded from analyses due to infrequent administration. The full WAIS-IV Digit Span was disproportionately administered to the manifest group. The premanifest group showed stronger cognitive performance with effect sizes in the large range on subtests of the WAIS-IV Digit Span, HVLT-R, SDMT, and verbal fluency. CONCLUSIONS: This is the first study to assess an empirically supported neuropsychological research battery in a clinical setting with a relatively large sample size given the rarity of HD. The battery adequately captured areas of impairment across the disease spectrum. Application of the current battery with larger premanifest samples is warranted.


Assuntos
Doença de Huntington , Adulto , Humanos , Doença de Huntington/complicações , Doença de Huntington/psicologia , Projetos Piloto , Estudos Retrospectivos , Testes Neuropsicológicos
2.
Mov Disord Clin Pract ; 10(12): 1714-1724, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38094638

RESUMO

Background: The clinical diagnosis of manifest Huntington's disease (HD) relies on a high level of clinical confidence (99% confidence) of HD-consistent motor signs. Longitudinal data have reliably identified cognitive and behavioral dysfunction predating clinical motor diagnosis by up to 15 years. Reliance on motor signs to establish a diagnosis of HD increases risk of early misdiagnosis or delayed diagnosis. Clinical neuropsychologists are uniquely positioned to advise on the clinical application of the Movement Disorder Society Task Force's recently proposed non-motor diagnostic criteria for HD. Objectives: To provide (1) a recommended clinical approach toward non-motor diagnostic criteria in persons with HD and facilitation of accurate diagnosis; (2) recommended practices for medical treatment providers to screen and longitudinally monitor non-motor signs of HD. Methods: The Huntington Study Group re-established the Neuropsychology Working Group, then recruited a multi-disciplinary group of neuropsychologists, neurologists, and psychiatrists to conduct an unstructured literature review and discuss expert opinions on practice, to facilitate an informal consensus opinion to accomplish the objectives. Results: The opinion and an example protocol for medical treatment providers to screen, monitor, and triage non-motor signs and symptoms of Huntington's disease is provided. Conclusions: Clinical diagnosis of non-motor HD is empirically justified and clinically important. Screening and triage by non-neuropsychologist clinicians can aid in detecting and monitoring non-motor Huntington's disease manifestation. The Neuropsychology Working Group consensus advances good clinical practice, clinical research, and quality of life. A companion position paper presenting the details of our consensus opinion regarding evidence-based guidelines for neuropsychological practice is forthcoming.

3.
Clin Neuropsychol ; : 1-23, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37849335

RESUMO

Objective: Neuropsychological evaluation is critical to detection and management of cognitive and neuropsychiatric changes associated with Huntington disease (HD). Accurate assessment of non-motor complications of HD is critical given the prominent impact on functional disability, frequently commensurate with or exceeding that of motor symptoms. The increasing emphasis on developing disease-modifying therapies targeting cognitive decline in HD requires consensus on clinical neuropsychological assessment methods. The Neuropsychology Working Group (NPWG) of the Huntington Study Group (HSG) sought to provide evidence and consensus-based, practical guidelines for the evaluation of cognitive and neuropsychiatric symptoms associated with HD. Method: The NPWG recruited a multi-disciplinary group of neuropsychologists, neurologists, and psychiatrists to inform best practices in assessing, diagnosing, and treating the non-motor symptoms in HD. A review was circulated among the NPWG, and in an iterative process informed by reviewed literature, best practices in neuropsychological evaluation of patients with HD were identified. Results: A brief review of the available literature and rational for a clinical consensus battery is offered. Conclusion: Clinical neuropsychologists are uniquely positioned to both detect and characterize the non-motor symptoms in HD, and further, provide neurologists and allied health professions with clinically meaningful information that impacts functional outcomes and quality of life. The NPWG provides guidance on best practices to clinical neuropsychologists in this statement. A companion paper operationalizing clinical application of previous research-based non-motor diagnostic criteria for HD is forthcoming, which also advises on non-motor symptom screening methods for the non-neuropsychologist working with HD.

4.
J Neuropsychiatry Clin Neurosci ; 35(2): 121-132, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36353818

RESUMO

OBJECTIVE: Apathy is a common behavioral symptom of Huntington disease (HD). This systematic review describes current evidence on the pathophysiology, assessment, and frequency of apathy in HD. METHODS: This systematic review was conducted in accordance with PRISMA guidelines. Using a comprehensive search strategy, the investigators searched the MEDLINE, Embase, and PsycINFO databases. All studies that evaluated apathy in HD patients with a valid scale and reported apathy frequency or scores were included. Apathy scores were analyzed by mean or standardized mean differences in accordance with Cochrane guidelines. RESULTS: A total of 1,085 records were screened and 80 studies were ultimately included. The Problem Behaviors Assessment-Short was the most frequently used apathy assessment tool. Apathy frequency generally ranged from 10%-33% in premanifest HD to 24%-76% in manifest HD. A meta-analysis of 5,311 records of patients with premanifest HD showed significantly higher apathy scores, with a standardized mean difference of 0.41 (CI=0.29-0.52; p<0.001). A comparison of 1,247 patients showed significantly higher apathy scores in manifest than premanifest HD, with a mean difference of 1.87 (CI=1.48-2.26; p<0.001). There was evidence of involvement of various cortical and subcortical brain regions in HD patients with apathy. CONCLUSIONS: Apathy was more frequent among individuals with premanifest HD compared with those in a control group and among individuals with manifest HD compared with those with premanifest HD. Considering the complexity and unique pattern of development in neurodegenerative disease, further studies are required to explore the pathophysiology of apathy in HD.


Assuntos
Apatia , Doença de Huntington , Doenças Neurodegenerativas , Humanos , Apatia/fisiologia , Encéfalo , Sintomas Comportamentais
5.
Clin Neuropsychol ; 36(2): 227-244, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35001854

RESUMO

In recognition that insufficient diversity in research impedes the generalizability of findings and negatively impacts clinical outcomes, the 1993 National Institutes of Health (NIH) Revitalization Act required NIH-funded clinical trials to include and assess outcomes for women and minority participants. Since that time, the American Psychological Association (APA) and the American Academy of Clinical Neuropsychology (AACN) have also acknowledged the reporting of this information as an essential element of research, and they have established similar aspirational goals. Nevertheless, Black communities remain disproportionately underrepresented in neuropsychology research. The objective of this study was to investigate current levels of inclusion and reporting of Black research participation in neuropsychological studies.Publications from high impact neuropsychology journals between 2019-2020 were selected via established methodologies. Studies were analyzed to determine the rates of demographic inclusion and reporting of minority, particularly Black, participants.A total of 1,764 articles were reviewed across seven neuropsychology journals. Of the 653 studies not excluded for other reasons, 43% neglected to include sufficient information about participants' race/ethnicity. Of the subset of eligible studies that did include racial/ethnic demographic information (n = 349), only 61% included any Black participants at all. Only 34.1% of them included enough Black participants equal to or greater than the proportion of Black individuals within the United States.Setting a standard of routinely reporting and analytically reflecting on demographic information is necessary to make valid inferences regarding disease sequelae, treatment, and public health strategies. The authors offer specific recommendations to improve the inclusion and reporting of Black research participation, ensure compliance with established policies, and improve the quality of neuropsychological research.


Assuntos
Etnicidade , Grupos Minoritários , População Negra , Feminino , Humanos , National Institutes of Health (U.S.) , Testes Neuropsicológicos , Estados Unidos
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 7594-7597, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34892848

RESUMO

This work presents a wireless time-scaling chaotic shift keying encryption system that can be used in wireless body area network applications. In wireless sensor nodes, the communication protocol being used provides some security measures and is implemented in software. However, no additional security measures are usually implemented. This paper demonstrates a discrete level real time encryption system using analog circuitry on a printed circuit board. The encryption system uses op amps, multipliers and resistors to implement the encryption. To implement wireless capabilities, commercial wireless microcontrollers using Bluetooth Low Energy were added, and a custom Bluetooth Low Energy profile was created to stream the analog encrypted signal.Clinical relevance- This work demonstrates an encryption system for wireless sensor devices for improved protection of private health information.


Assuntos
Algoritmos , Segurança Computacional , Comunicação , Redes de Comunicação de Computadores , Software
7.
J Am Pharm Assoc (2003) ; 61(5): e126-e131, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33931352

RESUMO

BACKGROUND: Second-generation antipsychotics are associated with lower risks of extrapyramidal symptoms, including tardive dyskinesia. However, many second-generation antipsychotics are associated with metabolic adverse effects, including weight gain, impaired blood glucose control, and hyperlipidemia. Metabolic monitoring for patients prescribed antipsychotic medication is 1 of several measures of the Centers for Medicare & Medicaid Services' Inpatient Psychiatric Facility Quality Reporting program. Screening for metabolic disorders (SMD) must be obtained within the previous 365 days before the hospital discharge date. National data suggest that compliance with this measure is low. OBJECTIVE: To improve compliance of metabolic monitoring by 20% while ensuring that the quality improvement interventions did not cause any unintended adverse effects on other aspects of our system. PRACTICE DESCRIPTION: This quality initiative was conducted at a large, 2000-bed academic medical center with approximately 80 inpatient psychiatric beds. PRACTICE INNOVATION: To improve the metabolic screening rates, a pharmacist collaborative practice agreement (CPA) was established as part of a quality improvement project. Previously, there were no formal processes at the institution to ensure that appropriate laboratory tests were conducted. EVALUATION METHODS: Using an uncontrolled before-and-after design, SMD data were gathered from 6 months before and 6 months after CPA implementation. Pearson chi-square test or Fisher exact test were used to compare the pre- and postintervention groups in this quasi-experimental design. RESULTS: Compared with the preintervention period, compliance of SMD monitoring increased by 21.2% in the postintervention phase-from 69.2% to 90.4% (P < 0.001). CONCLUSION: The empowerment of clinical pharmacists with a CPA significantly improved guideline-concordant metabolic monitoring of antipsychotics. These findings may have significant impact on the approach to the safe use of these essential psychotropic medications and provide a framework for other inpatient mental health facilities to optimally use the skills of their interdisciplinary team.


Assuntos
Assistência Farmacêutica , Farmácia , Idoso , Humanos , Pacientes Internados , Medicare , Farmacêuticos , Estados Unidos
8.
Arch Psychiatr Nurs ; 33(1): 112-119, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30663614

RESUMO

BACKGROUND: Violence is a large concern for mental health professionals: 90% of physicians and nurses working in mental health areas have been subject to violence from patients. Approximately 80% of violent acts from patients are directed toward nurses. OBJECTIVE: The purpose of this integrative literature review was to identify violence risk-assessment screening tools that could be used in acute care mental health settings. DESIGN: The Stetler model of evidence-based practice guided the literature search, in which 8 violence risk-assessment tools were identified, 4 of which were used for further examination. RESULTS: The Brøset Violence Checklist and Violence Risk Screening-10 provided the best assessment for violence in the acute care mental health setting. CONCLUSIONS: Using a violence risk assessment screening tool helps identify patients at risk for violence allowing for quick intervention to prevent violent episodes.


Assuntos
Programas de Rastreamento , Saúde Mental , Medição de Risco , Inquéritos e Questionários , Violência/prevenção & controle , Agressão , Feminino , Pessoal de Saúde , Humanos , Programas de Rastreamento/métodos , Transtornos Mentais/terapia
10.
J Psychosoc Oncol ; 36(4): 454-469, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29863447

RESUMO

PURPOSE: The extent to which patients feel prepared for end-of-life (EOL) may be associated with important clinical outcomes. Despite growing interest in the concept of "preparedness," however, there is insufficient information about what cancer patients actually need to feel prepared. Such information is foundational for patient-centered care, theory-building, and instrument development. DESIGN: This qualitative study examined patient perspectives regarding preparedness for EOL care. PARTICIPANTS AND METHODS: In-depth interviews were conducted with patients with advanced malignancies and limited life expectancies. Participants were drawn from a large academic cancer center and had a diverse range of malignancies. Thematic text analysis was used to analyze the data. FINDINGS: Six overarching themes emerged. These included readiness to manage concerns about: (1) EOL planning (e.g., goals of care, location of care); (2) interactions with healthcare providers (e.g., communication, symptom control); (3) interactions with family/friends (e.g., perceived burden, support); (4) emotional well-being (e.g., existential distress, fulfillment); (5) spiritual well-being (e.g., spiritual comfort, congregational support); and (6) financial well-being (e.g., medical expenses, estate planning). CONCLUSIONS: Findings highlight areas that patients themselves regard as critical for a sense of preparedness for EOL care. Participants emphasized broader concerns than those previously construed as facets of patient preparedness, and these domains offer modifiable targets for intervention.


Assuntos
Atitude Frente a Saúde , Neoplasias/terapia , Pacientes/psicologia , Assistência Terminal/psicologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pacientes/estatística & dados numéricos , Pesquisa Qualitativa
11.
Psychol Serv ; 15(4): 477-485, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29022739

RESUMO

The purpose of this study was to develop the Offender Job Search Self-Efficacy Scale (OFJSSE) for the specific job search needs of the criminal justice population. Participants were 249 male inmates within 2 years of release from a state correctional facility in the southern region of the United States who identified mostly as Caucasian (56.2%), single (62.2%), working-class (45.4%) men with a mean age of 36.27 years (SD = 10.38). Initial validation data are described, including results of an exploratory factor analysis. Results indicated that the OFJSSE presents excellent reliability (α = .95) as well as good convergent and discriminant validity by having a strong, positive correlation, r = .73, p < .01, with another job search scale and having a negative correlation, r = -.19, p = .01, with a scale measuring a different construct (i.e., criminal thinking). Implications of the findings as well as limitations and future directions are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).


Assuntos
Criminosos/psicologia , Emprego/psicologia , Prisioneiros/psicologia , Psicometria , Autoeficácia , Adolescente , Adulto , Idoso , Escolha da Profissão , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria/instrumentação , Psicometria/métodos , Psicometria/normas , Reprodutibilidade dos Testes , Desejabilidade Social , Adulto Jovem
12.
Am Surg ; 81(10): 1053-6, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26463307

RESUMO

Breast cancer detection in women with implants has been questioned. We sought to evaluate the impact of breast implants on mammographic outcomes. A retrospective review of women undergoing mammography between March 1 and October 30, 2013 was performed. Demographic characteristics and mammogram results were compared between women with and without breast implants. Overall, 4.8 per cent of 1863 women identified during the study period had breast implants. Median age was 59 years (26-93). Women with implants were younger (53.9 vs 59.2 years, P < 0.0001), had lower body mass index (25.4 vs 28.9, P < 0.0001), and were more likely to have dense breast tissue (72.1% vs 56.4%, P = 0.004) than those without. There were no statistically significant differences with regards to Breast Imaging Recording and Data System 0 score (13.3% with implants vs 21.4% without), call back exam (18.9% with vs 24.1% without), time to resolution of abnormal imaging (58.6 days with vs 43.3 without), or cancer detection rate (0% with implants vs 1.0% without). Because implants did not significantly affect mammogram results, women with implants should be reassured that mammography remains useful in detecting cancer. However, future research is required to determine whether lower call back rates and longer time to resolution of imaging findings contribute to delays in diagnosis in patients with implants.


Assuntos
Implantes de Mama/efeitos adversos , Neoplasias da Mama/diagnóstico , Detecção Precoce de Câncer , Mamografia/métodos , Programas de Rastreamento/métodos , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/etiologia , California/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
13.
Int J Endocrinol ; 2015: 401851, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26448747

RESUMO

African American women suffer higher incidence and mortality of triple negative breast cancer (TNBC) than Caucasian women. TNBC is very aggressive, causing the worst clinical outcome. We previously demonstrated that tumors from these patients express high IGF-II and exhibit high activation of the IGF signaling pathways. IGF-II gene expression is imprinted (monoallelic), promotes tumor progression, and metastasis and regulates Survivin, a TNBC prognostic marker. Since BC mortality has increased among young Vietnamese women, we analyzed 48 (paired) TNBC samples from Vietnamese patients to assess IGF-II expression. We analyzed all samples by qrtPCR for identification of IGF-II heterozygosity and to determine allelic expression of the IGF-II gene. We also analyzed the tissues for proIGF-II and Survivin by RT-PCR and Western blotting. A total of 28 samples displayed IGF-II heterozygosity of which 78% were biallelic. Tumors with biallelic IGF-II gene expression exhibited the highest levels of proIGF-II and Survivin. Although 100% of these tissues corresponding normal samples were biallelic, they expressed significantly lower levels of or no proIGF-II and Survivin. Thus, IGF-II biallelic gene expression is differentially regulated in normal versus tumor tissues. We propose that intratumoral proIGF-II is dependent on the IGF-II gene imprinting status and it will promote a more aggressive TNBC.

14.
Hum Mol Genet ; 24(2): 492-505, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25214536

RESUMO

Approaches targeting nitric oxide (NO) signaling show promise as therapies for Duchenne and Becker muscular dystrophies. However, the mechanisms by which NO benefits dystrophin-deficient muscle remain unclear, but may involve nNOSß, a newly discovered enzymatic source of NO in skeletal muscle. Here we investigate the impact of dystrophin deficiency on nNOSß and use mdx mice engineered to lack nNOSµ and nNOSß to discern how the loss of nNOS impacts dystrophic skeletal muscle pathology. In mdx muscle, nNOSß was mislocalized and its association with the Golgi complex was reduced. nNOS depletion from mdx mice prevented compensatory skeletal muscle cell hypertrophy, decreased myofiber central nucleation and increased focal macrophage cell infiltration, indicating exacerbated dystrophic muscle damage. Reductions in muscle integrity in nNOS-null mdx mice were accompanied by decreases in specific force and increased susceptibility to eccentric contraction-induced muscle damage compared with mdx controls. Unexpectedly, muscle fatigue was unaffected by nNOS depletion, revealing a novel latent compensatory mechanism for the loss of nNOS in mdx mice. Together with previous studies, these data suggest that localization of both nNOSµ and nNOSß is disrupted by dystrophin deficiency. They also indicate that nNOS has a more complex role as a modifier of dystrophic pathology and broader therapeutic potential than previously recognized. Importantly, these findings also suggest nNOSß as a new drug target and provide a new conceptual framework for understanding nNOS signaling and the benefits of NO therapies in dystrophinopathies.


Assuntos
Contração Muscular , Distrofia Muscular de Duchenne/enzimologia , Distrofia Muscular de Duchenne/imunologia , Óxido Nítrico Sintase Tipo I/metabolismo , Animais , Distrofina/genética , Distrofina/metabolismo , Complexo de Golgi/enzimologia , Humanos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Camundongos Knockout , Músculo Esquelético/enzimologia , Músculo Esquelético/imunologia , Músculo Esquelético/fisiopatologia , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/fisiopatologia , Óxido Nítrico Sintase Tipo I/genética
15.
J Neurosci ; 30(33): 11004-10, 2010 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-20720107

RESUMO

At the neuromuscular junction (NMJ), the dystrophin protein complex provides a scaffold that functions to stabilize acetylcholine receptor (AChR) clusters. Syntrophin, a key component of that scaffold, is a multidomain adapter protein that links a variety of signaling proteins and ion channels to the dystrophin protein complex. Without syntrophin, utrophin and neuronal nitric oxide synthase mu (nNOSmu) fail to localize to the NMJ and the AChRs are distributed abnormally. Here we investigate the contribution of syntrophin domains to AChR distribution and to localization of utrophin and nNOSmu at the NMJ. Transgenic mice expressing alpha-syntrophin lacking portions of the first pleckstrin homology (PH) domain (DeltaPH1a or DeltaPH1b) or the entire PDZ domain (DeltaPDZ) were bred onto the alpha-syntrophin null background. As expected the DeltaPDZ transgene did not restore the NMJ localization of nNOS. The DeltaPH1a transgene did restore postsynaptic nNOS but surprisingly did not restore sarcolemmal nNOS (although sarcolemmal aquaporin-4 was restored). Mice lacking the alpha-syntrophin PDZ domain or either half of the PH1 domain were able to restore utrophin to the NMJ but did not correct the aberrant AChR distribution of the alpha-syntrophin knock-out mice. However, mice expressing both the transgenic DeltaPDZ and the transgenic DeltaPH1a constructs did restore normal AChR distribution, demonstrating that both domains are required but need not be confined within the same protein to function. We conclude that the PH1 and PDZ domains of alpha-syntrophin work in concert to facilitate the localization of AChRs and nNOS at the NMJ.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Junção Neuromuscular/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Receptores Colinérgicos/metabolismo , Utrofina/metabolismo , Animais , Aquaporina 4/metabolismo , Feminino , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Músculo Esquelético/metabolismo , Domínios PDZ , RNA Mensageiro/metabolismo , Sarcolema/metabolismo
16.
J Clin Invest ; 120(3): 816-26, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20124730

RESUMO

Signaling via the neuronal NOS (nNOS) splice variant nNOSmu is essential for skeletal muscle health and is commonly reduced in neuromuscular disease. nNOSmu is thought to be the predominant source of NO in skeletal muscle. Here we demonstrate the existence of what we believe to be a novel signaling pathway, mediated by the nNOS splice variant nNOSbeta, localized at the Golgi complex in mouse skeletal muscle cells. In contrast to muscles lacking nNOSmu alone, muscles missing both nNOSmu and nNOSbeta were severely myopathic, exhibiting structural defects in the microtubule cytoskeleton, Golgi complex, and mitochondria. Skeletal muscles lacking both nNOSmu and nNOSbeta were smaller in mass, intrinsically weak, highly susceptible to fatigue, and exhibited marked postexercise weakness. Our data indicate that nNOSbeta is a critical regulator of the structural and functional integrity of skeletal muscle and demonstrate the existence of 2 functionally distinct nNOS microdomains in skeletal muscle, created by the differential targeting of nNOSmu to the sarcolemma and nNOSbeta to the Golgi. We have previously shown that sarcolemmal nNOSmu matches the blood supply to the metabolic demands of active muscle. We now demonstrate that nNOSbeta simultaneously modulates the ability of skeletal muscle to maintain force production during and after exercise. We conclude therefore that nNOS splice variants are critical regulators of skeletal muscle exercise performance.


Assuntos
Contração Muscular , Fadiga Muscular , Fibras Musculares Esqueléticas/enzimologia , Músculo Esquelético/enzimologia , Óxido Nítrico Sintase Tipo I/metabolismo , Sarcolema/enzimologia , Processamento Alternativo/genética , Animais , Linhagem Celular , Citoesqueleto/enzimologia , Citoesqueleto/patologia , Isoenzimas/genética , Isoenzimas/metabolismo , Camundongos , Fibras Musculares Esqueléticas/patologia , Músculo Esquelético/patologia , Óxido Nítrico Sintase Tipo I/genética , Condicionamento Físico Animal , Sarcolema/genética , Sarcolema/patologia
17.
PLoS One ; 3(10): e3387, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18852886

RESUMO

Skeletal muscle nNOSmu (neuronal nitric oxide synthase mu) localizes to the sarcolemma through interaction with the dystrophin-associated glycoprotein (DAG) complex, where it synthesizes nitric oxide (NO). Disruption of the DAG complex occurs in dystrophinopathies and sarcoglycanopathies, two genetically distinct classes of muscular dystrophy characterized by progressive loss of muscle mass, muscle weakness and increased fatigability. DAG complex instability leads to mislocalization and downregulation of nNOSmu; but this is thought to play a minor role in disease pathogenesis. This view persists without knowledge of the role of nNOS in skeletal muscle contractile function in vivo and has influenced gene therapy approaches to dystrophinopathy, the majority of which do not restore sarcolemmal nNOSmu. We address this knowledge gap by evaluating skeletal muscle function in nNOS knockout (KN1) mice using an in situ approach, in which the muscle is maintained in its normal physiological environment. nNOS-deficiency caused reductions in skeletal muscle bulk and maximum tetanic force production in male mice only. Furthermore, nNOS-deficient muscles from both male and female mice exhibited increased susceptibility to contraction-induced fatigue. These data suggest that aberrant nNOSmu signaling can negatively impact three important clinical features of dystrophinopathies and sarcoglycanopathies: maintenance of muscle bulk, force generation and fatigability. Our study suggests that restoration of sarcolemmal nNOSmu expression in dystrophic muscles may be more important than previously appreciated and that it should be a feature of any fully effective gene therapy-based intervention.


Assuntos
Músculo Esquelético/enzimologia , Músculo Esquelético/fisiopatologia , Doenças Musculares/etiologia , Óxido Nítrico Sintase Tipo I/deficiência , Animais , Complexo de Proteínas Associadas Distrofina/metabolismo , Fadiga/etiologia , Feminino , Masculino , Camundongos , Camundongos Knockout , Força Muscular , Músculo Esquelético/patologia , Doenças Musculares/enzimologia , Sarcolema/enzimologia , Fatores Sexuais
18.
J Cell Sci ; 121(Pt 1): 48-54, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18057022

RESUMO

alpha-Dystrobrevin associates with and is a homologue of dystrophin, the protein linked to Duchenne and Becker muscular dystrophies. We used a transgenic approach to restore alpha-dystrobrevin to the sarcolemma in mice that lack dystrophin (mdx mice) to study two interrelated functions: (1) the ability of alpha-dystrobrevin to rescue components of the dystrophin complex in the absence of dystrophin and (2) the ability of sarcolemmal alpha-dystrobrevin to ameliorate the dystrophic phenotype. We generated transgenic mice expressing alpha-dystrobrevin-2a linked to a palmitoylation signal sequence and bred them onto the alpha-dystrobrevin-null and mdx backgrounds. Expression of palmitoylated alpha-dystrobrevin prevented the muscular dystrophy observed in the alpha-dystrobrevin-null mice, demonstrating that the altered form of alpha-dystrobrevin was functional. On the mdx background, the palmitoylated form of alpha-dystrobrevin was expressed on the sarcolemma but did not significantly ameliorate the muscular dystrophy phenotype. Palmitoylated dystrobrevin restored alpha-syntrophin and aquaporin-4 (AQP4) to the mdx sarcolemma but was unable to recruit beta-dystroglycan or the sarcoglycans. Despite restoration of sarcolemmal alpha-syntrophin, neuronal nitric oxide synthase (nNOS) was not localized to the sarcolemma, suggesting that nNOS requires both dystrophin and alpha-syntrophin for correct localization. Thus, although nNOS and AQP4 both require interaction with the PDZ domain of alpha-syntrophin for sarcolemmal association, their localization is regulated differentially.


Assuntos
Aquaporina 4/genética , Proteínas Associadas à Distrofina/genética , Distrofina/genética , Neuropeptídeos/genética , Óxido Nítrico Sintase Tipo I/genética , Sarcolema/metabolismo , Animais , Distrofina/química , Distrofina/metabolismo , Proteínas Associadas à Distrofina/metabolismo , Lipoilação , Camundongos , Camundongos Endogâmicos mdx , Camundongos Knockout , Camundongos Transgênicos , Microscopia de Fluorescência , Músculos/metabolismo , Músculos/patologia , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/patologia , Neuropeptídeos/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Domínios PDZ , Ligação Proteica , Sarcolema/química
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