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1.
Clin Infect Dis ; 75(8): 1389-1396, 2022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-35176755

RESUMO

BACKGROUND: Biological sex and the estrogen receptor alpha (ESR1) modulate human immunodeficiency virus (HIV) activity. Few women have enrolled in clinical trials of latency reversal agents (LRAs); their effectiveness in women is unknown. We hypothesized that ESR1 antagonism would augment induction of HIV expression by the LRA vorinostat. METHODS: AIDS Clinical Trials Group A5366 enrolled 31 virologically suppressed, postmenopausal women on antiretroviral therapy. Participants were randomized 2:1 to receive tamoxifen (arm A, TAMOX/VOR) or observation (arm B, VOR) for 5 weeks followed by 2 doses of vorinostat. Primary end points were safety and the difference between arms in HIV RNA induction after vorinostat. Secondary analyses included histone 4 acetylation, HIV DNA, and plasma viremia by single copy assay (SCA). RESULTS: No significant adverse events were attributed to study treatments. Tamoxifen did not enhance vorinostat-induced HIV transcription (between-arm ratio, 0.8; 95% confidence interval [CI], .2-2.4). Vorinostat-induced HIV transcription was higher in participants with increases in H4Ac (fold increase, 2.78; 95% CI, 1.34-5.79) vs those 9 who did not (fold increase, 1.04; 95% CI, .25-4.29). HIV DNA and SCA plasma viremia did not substantially change. CONCLUSIONS: Tamoxifen did not augment vorinostat-induced HIV RNA expression in postmenopausal women. The modest latency reversal activity of vorinostat, postmenopausal status, and low level of HIV RNA expression near the limits of quantification limited assessment of the impact of tamoxifen. This study is the first HIV cure trial done exclusively in women and establishes both the feasibility and necessity of investigating novel HIV cure strategies in women living with HIV. CLINICAL TRIALS REGISTRATION: NCT03382834.


Assuntos
Síndrome da Imunodeficiência Adquirida , Infecções por HIV , HIV-1 , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Linfócitos T CD4-Positivos , DNA/uso terapêutico , Receptor alfa de Estrogênio/metabolismo , Feminino , HIV-1/genética , Inibidores de Histona Desacetilases/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/uso terapêutico , Histonas/metabolismo , Histonas/uso terapêutico , Humanos , RNA/metabolismo , RNA/uso terapêutico , Tamoxifeno/efeitos adversos , Tamoxifeno/metabolismo , Viremia/tratamento farmacológico , Latência Viral , Vorinostat/metabolismo , Vorinostat/farmacologia , Vorinostat/uso terapêutico
2.
AIDS Res Hum Retroviruses ; 36(4): 268-282, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32160755

RESUMO

Women remain underrepresented in HIV research. The AIDS Clinical Trials Group (ACTG) 5366 study was the first HIV cure-related trial conducted exclusively in women. Our multidisciplinary team integrated participant-centered reports into the ACTG 5366 protocol to elicit their perspectives. We nested mixed-methods surveys at the enrollment and final study visits to assess ACTG 5366 participants' perceptions and experiences. Of 31 participants enrolled in the ACTG 5366, 29 study agreed to complete the entry questionnaire and 27 completed the exit survey. The majority of study participants were nonwhite. We identified societal and personal motivators for participation, understanding of risks and benefits, and minor misconceptions among some trial participants. Stigma was pervasive for several women who joined the study, and served as a motivator for study participation. Reimbursements to defray costs of study participation were reported to facilitate involvement in the trial by about one-third of participants. Almost all respondents reported positive experiences participating in the ACTG 5366 trial. The ACTG 5366 study showed that it is possible to recruit and retain women in HIV cure-related research and to embed participant-centered outcomes at strategic time points during the study. The findings could help in the design, implementation, recruitment, and retention of women in HIV cure-related research and highlight the value of assessing psychosocial factors in HIV cure-related research participation.


Assuntos
Infecções por HIV/psicologia , Participação do Paciente/psicologia , Inquéritos e Questionários , Fármacos Anti-HIV/uso terapêutico , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Pesquisa Qualitativa , Medição de Risco , Estigma Social , Tamoxifeno/uso terapêutico , Estados Unidos , Vorinostat/uso terapêutico
3.
Lancet HIV ; 2(1): e12-9, 2015 01.
Artigo em Inglês | MEDLINE | ID: mdl-26424232

RESUMO

BACKGROUND: Adherence is key to the success of antiretroviral therapy. Enhanced partner support might benefit patients with previous treatment failure. We aimed to assess whether an enhanced partner-based support intervention with modified directly observed therapy would improve outcomes with second-line therapy in HIV-infected patients for whom first-line therapy had failed. METHODS: We did a multicentre, international, randomised clinical trial at nine sites in Botswana, Brazil, Haiti, Peru, South Africa, Uganda, Zambia, and Zimbabwe. Participants aged 18 years or older for whom first-line therapy had failed, with HIV RNA concentrations greater than 1000 copies per mL and with a willing partner, were randomly assigned (1:1), via computer-generated randomisation, to receive partner-based modified directly observed therapy or standard of care. Randomisation was stratified by screening HIV RNA concentration (≤10 000 copies per mL vs >10 000 copies per mL). Participants and site investigators were not masked to group assignment. Primary outcome was confirmed virological failure (viral load >400 copies per mL) by week 48. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00608569. FINDINGS: Between April 23, 2009, and Sept 29, 2011, we randomly assigned 259 participants to the modified directly observed therapy group (n=129) or the standard-of-care group (n=130). 34 (26%) participants in the modified directly observed therapy group achieved the primary endpoint of virological failure by week 48 compared with 23 (18%) participants in the standard-of-care group. The Kaplan-Meier estimated cumulative probability of virological failure by week 48 was 25·1% (95% CI 17·7-32·4) in the modified directly observed therapy group and 17·3% (10·8-23·7) in the standard-of-care group, for a weighted difference in standard of care versus modified directly observed therapy of -6·6% (95% CI -16·5% to 3·2%; p=0·19). 36 (14%) participants reported at least one grade 3 or higher adverse event or laboratory abnormality (n=21 in the modified directly observed therapy group and n=15 in the standard-of-care group). INTERPRETATION: Partner-based training with modified directly observed therapy had no effect on virological suppression. The intervention does not therefore seem to be a promising strategy to increase adherence. Intensive follow-up with clinic staff might be a viable approach in this setting. FUNDING: AIDS Clinical Trials Group and the National Institute of Allergy and Infectious Diseases, US National Institutes of Health.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , Adesão à Medicação/psicologia , Adulto , Terapia Antirretroviral de Alta Atividade/métodos , Agendamento de Consultas , Botsuana , Brasil , Feminino , Infecções por HIV/virologia , Haiti , Humanos , Masculino , Pessoa de Meia-Idade , Peru , Pesquisadores , África do Sul , Padrão de Cuidado , Falha de Tratamento , Uganda , Estados Unidos , Carga Viral/efeitos dos fármacos , Zimbábue
4.
PLoS One ; 10(7): e0131001, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26148192

RESUMO

OBJECTIVE: Many studies include oral HIV-related endpoints that may be diagnosed by non-oral-health specialists (non-OHS) like nurses or physicians. Our objective was to assess the accuracy of clinical diagnoses of HIV-related oral lesions made by non-OHS compared to diagnoses made by OHS. METHODS: A5254, a cross-sectional study conducted by the Oral HIV/AIDS Research Alliance within the AIDS Clinical Trial Group, enrolled HIV-1-infected adults participants from six clinical trial units (CTU) in the US (San Francisco, New York, Chapel Hill, Cleveland, Atlanta) and Haiti. CTU examiners (non-OHS) received standardized training on how to perform an oral examination and make clinical diagnoses of specific oral disease endpoints. Diagnoses by calibrated non-OHS were compared to those made by calibrated OHS, and sensitivity and specificity computed. RESULTS: Among 324 participants, the majority were black (73%), men (66%), and the median CD4+ cell count 138 cells/mm(3). The overall frequency of oral mucosal disease diagnosed by OHS was 43% in US sites, and 90% in Haiti. Oral candidiasis (OC) was detected in 153 (47%) by OHS, with erythematous candidiasis (EC) the most common type (39%) followed by pseudomembranous candidiasis (PC; 26%). The highest prevalence of OC (79%) was among participants in Haiti, and among those with CD4+ cell count ≤ 200 cells/mm(3) and HIV-1 RNA > 1000 copies/mL (71%). The sensitivity and specificity of OC diagnoses by non-OHS were 90% and 92% (for EC: 81% and 94%; PC: 82% and 95%). Sensitivity and specificity were also high for KS (87% and 94%, respectively), but sensitivity was < 60% for HL and oral warts in all sites combined. The Candida culture confirmation of OC clinical diagnoses (as defined by ≥ 1 colony forming unit per mL of oral/throat rinse) was ≥ 93% for both PC and EC. CONCLUSION: Trained non-OHS showed high accuracy of clinical diagnoses of OC in comparison with OHS, suggesting their usefulness in studies in resource-poor settings, but detection of less common lesions may require OHS.


Assuntos
Competência Clínica , Diagnóstico Bucal , Erros de Diagnóstico , Infecções por HIV/complicações , HIV-1 , Pessoal de Saúde , Doenças da Boca/diagnóstico , Adulto , Idoso , Contagem de Linfócito CD4 , Calibragem , Estudos Transversais , Higienistas Dentários , Odontólogos , Diagnóstico Bucal/educação , Feminino , Haiti/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Doenças da Boca/complicações , Doenças da Boca/epidemiologia , Medicina Bucal , Otolaringologia , Prevalência , Sensibilidade e Especificidade , Especialização , Estados Unidos/epidemiologia , Carga Viral , Recursos Humanos , Adulto Jovem
5.
J Neurovirol ; 20(6): 620-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25377444

RESUMO

Elevated cerebrospinal fluid (CSF) levels of markers of oxidative stress, neuronal injury, and inflammation and decreased neurotransmitter levels have been reported in HIV-associated neurocognitive disorders (HAND). Minocycline may have a neuroprotective effect by inhibiting inducible nitric oxide synthase, which produces nitric oxide, a compound that induces oxygen free radical production. In A5235, "Phase II, Randomized, Placebo-Controlled, Double-Blind Study of Minocycline in the Treatment of HIV-Associated Cognitive Impairment," minocycline was not associated with cognitive improvement, but the effect on the above CSF measures was not examined previously. The objective of this study was to examine the effect of minocycline on markers of oxidative stress, neuronal injury, neurotransmitter levels, and inflammation from CSF in participants in A5235. One hundred seven HIV+ individuals received either minocycline 100 mg or placebo orally every 12 h for 24 weeks. Twenty-one HIV+ individuals received the optional lumbar punctures. Lipid and protein markers of oxidative stress (e.g., ceramides and protein carbonyls), glutamate, neurotransmitter precursors, kynurenine metabolites, neurofilament heavy chain, and inflammatory cytokines were measured in the CSF before and after treatment. The 24-week change in ceramides was larger in a beneficial direction in the minocycline group compared to the placebo group. The two groups did not differ in the 24-week changes for other markers.These results suggest that minocycline may decrease lipid markers of oxidative stress (ceramides) in individuals with HAND; however, an effect of minocycline on other CSF markers was not observed. A larger sample size is needed to further validate these results.


Assuntos
Complexo AIDS Demência/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Minociclina/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Complexo AIDS Demência/líquido cefalorraquidiano , Complexo AIDS Demência/patologia , Complexo AIDS Demência/virologia , Síndrome da Imunodeficiência Adquirida/líquido cefalorraquidiano , Síndrome da Imunodeficiência Adquirida/patologia , Síndrome da Imunodeficiência Adquirida/virologia , Administração Oral , Adulto , Ceramidas/líquido cefalorraquidiano , Citocinas/líquido cefalorraquidiano , Método Duplo-Cego , Feminino , Ácido Glutâmico/líquido cefalorraquidiano , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Humanos , Cinurenina/líquido cefalorraquidiano , Masculino , Pessoa de Meia-Idade , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Neurônios/efeitos dos fármacos , Neurônios/patologia , Neurônios/virologia , Óxido Nítrico Sintase Tipo II/líquido cefalorraquidiano , Estresse Oxidativo
6.
Brain Stimul ; 5(4): 605-15, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22019080

RESUMO

BACKGROUND: Dopamine agonist therapy and deep brain stimulation (DBS) of the subthalamic nucleus (STN) are antiparkinsonian treatments that act on a different part of the basal ganglia-thalamocortical motor circuitry, yet produce similar symptomatic improvements. OBJECTIVE/HYPOTHESIS: The purpose of this study was to identify common and unique brain network features of these standard treatments. METHODS: We analyzed images produced by H(2)(15)O positron emission tomography (PET) of patients with Parkinson's disease (PD) at rest. Nine patients were scanned before and after injection of apomorphine, and 11 patients were scanned while bilateral stimulators were off and while they were on. RESULTS: Both treatments produced common deactivations of the neocortical sensorimotor areas, including the supplementary motor area, precentral gyrus, and postcentral gyrus, and in subcortical structures, including the putamen and cerebellum. We observed concomitant activations of the superior parietal lobule and the midbrain in the region of the substantia nigra/STN. We also detected unique, treatment-specific changes with possible motor-related consequences in the basal ganglia, thalamus, neocortical sensorimotor cortex, and posterolateral cerebellum. Unique changes in nonmotor regions may reflect treatment-specific effects on verbal fluency and limbic functions. CONCLUSIONS: Many of the common effects of these treatments are consistent with the standard pathophysiologic model of PD. However, the common effects in the cerebellum are not readily explained by the model. Consistent deactivation of the cerebellum is interesting in light of recent reports of synaptic pathways directly connecting the cerebellum and basal ganglia, and may warrant further consideration for incorporation into the model.


Assuntos
Antiparkinsonianos/uso terapêutico , Apomorfina/uso terapêutico , Encéfalo/diagnóstico por imagem , Estimulação Encefálica Profunda , Agonistas de Dopamina/uso terapêutico , Doença de Parkinson/terapia , Adulto , Idoso , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/tratamento farmacológico , Cintilografia , Resultado do Tratamento
7.
J Parkinsons Dis ; 2(1): 29-40, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23939406

RESUMO

Deep brain stimulation (DBS) of the subthalamic nucleus improves the motor symptoms of Parkinson's disease, but may produce a worsening of speech and language performance at rates and amplitudes typically selected in clinical practice. The possibility that these dissociated effects might be modulated by selective stimulation of left and right STN has never been systematically investigated. To address this issue, we analyzed motor, speech and language functions of 12 patients implanted with bilateral stimulators configured for optimal motor responses. Behavioral responses were quantified under four stimulator conditions: bilateral DBS, right-only DBS, left-only DBS and no DBS. Under bilateral and left-only DBS conditions, our results exhibited a significant improvement in motor symptoms but worsening of speech and language. These findings contribute to the growing body of literature demonstrating that bilateral STN DBS compromises speech and language function and suggests that these negative effects may be principally due to left-sided stimulation. These findings may have practical clinical consequences, suggesting that clinicians might optimize motor, speech and language functions by carefully adjusting left- and right-sided stimulation parameters.


Assuntos
Estimulação Encefálica Profunda , Lateralidade Funcional/fisiologia , Idioma , Movimento/fisiologia , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Fala/fisiologia , Núcleo Subtalâmico/fisiologia , Adulto , Idoso , Biofísica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
8.
J Acquir Immune Defic Syndr ; 50(3): 290-3, 2009 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-19194314

RESUMO

BACKGROUND: Rifampin is the cornerstone of antituberculosis therapy, but induction of hepatic cytochrome P4503A by rifampin markedly lowers HIV protease inhibitor plasma concentrations. METHODS: This phase 1, open-label, one-arm study was designed to assess pharmacokinetic interactions and safety of atazanavir, ritonavir, and rifampin among 14 evaluable HIV-seronegative volunteers. The study included 3 sequential periods of study drug dosing, with plasma sampling for pharmacokinetic analyses to occur on the last day of each period. During period 1, participants received rifampin 600 mg every 24 hours for 8 days. During period 2, participants continued rifampin 600 mg every 24 hours, and added atazanavir 300 mg and ritonavir 100 mg every 12 hours, to continue for at least 11 days. During period 3, atazanavir was to be increased to 400 mg every 12 hours. RESULTS: Upon adding atazanavir and ritonavir, the first 3 subjects developed vomiting and transaminase elevations resulting in study drug discontinuation. The study was therefore terminated. CONCLUSIONS: Coadministration of rifampin with HIV protease inhibitors may not be a viable treatment option if rifampin administration precedes protease inhibitor initiation. Future studies, which explore concomitant HIV protease inhibitors with rifampin must carefully consider the sequence in which drugs are initiated.


Assuntos
Antituberculosos/efeitos adversos , Trato Gastrointestinal/efeitos dos fármacos , Inibidores da Protease de HIV/efeitos adversos , Fígado/efeitos dos fármacos , Oligopeptídeos/efeitos adversos , Piridinas/efeitos adversos , Rifampina/efeitos adversos , Ritonavir/efeitos adversos , Adulto , Antituberculosos/administração & dosagem , Sulfato de Atazanavir , Feminino , Inibidores da Protease de HIV/administração & dosagem , Humanos , Masculino , Oligopeptídeos/administração & dosagem , Piridinas/administração & dosagem , Rifampina/administração & dosagem , Ritonavir/administração & dosagem
9.
Acta Psychol (Amst) ; 130(3): 214-24, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19178895

RESUMO

Participants were asked to recall the names when shown photographs of faces in both a semantic task (Experiment 1) and an episodic task (Experiments 2 and 3). When recall failed, feeling of knowing (FOK) ratings were solicited. In addition, participants reported on the strategies that they used to make their ratings, whether they could recall other pieces of information (the target-accessibility strategy, e.g., Koriat, A. (1993). How do we know that? The accessibility model of the feeling of knowing. Psychological Review, 100, 609-639) or whether the faces simply looked familiar (the cue-familiarity strategy, e.g., Schwartz, B. L., & Metcalfe, J. (1992). Cue familiarity but not target accessibility enhances feeling of knowing ratings. Journal of Experimental Psychology: Learning, Memory, and Cognition, 18, 1074-1083). In all experiments, FOK ratings were fairly accurate in that participants were successful in predicting their performance on a subsequent recognition test. More importantly, participants reported using the cue-familiarity strategy more often, although they gave higher FOK ratings when they reported using the target-accessibility strategy. The FOK ratings that were given using the two strategies were equally accurate.


Assuntos
Atitude , Cognição , Face , Nomes , Feminino , Humanos , Reconhecimento Psicológico , Adulto Jovem
10.
Antimicrob Agents Chemother ; 51(9): 3104-10, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17576825

RESUMO

The potent induction of hepatic cytochrome P450 3A isoforms by rifampin complicates therapy for coinfection with human immunodeficiency virus (HIV) and Mycobacterium tuberculosis. We performed an open-label, single-arm study to assess the safety and pharmacokinetic interactions of the HIV protease inhibitor atazanavir coadministered with rifampin. Ten healthy HIV-negative subjects completed pharmacokinetic sampling at steady state while receiving 300 mg atazanavir every 12 h without rifampin (period 1), 300 mg atazanavir every 12 h with 600 mg rifampin every 24 h (period 2), and 400 mg atazanavir every 12 h with 600 mg rifampin every 24 h (period 3). During period 1, the mean concentration of drug in serum at 12 h (C(12 h)) was 811 ng/ml (range, 363 to 2,484 ng/ml) for atazanavir, similar to historic seronegative data for once-daily treatment with 300 mg atazanavir boosted with 100 mg ritonavir. During periods 2 and 3, the mean C(12 h) values for atazanavir were 44 ng/ml (range, <25 to 187 ng/ml) and 113 ng/ml (range, 39 to 260 ng/ml), respectively, well below historic seronegative data for once-daily treatment with 400 mg atazanavir without ritonavir. Although safe and generally well tolerated, 300 mg or 400 mg atazanavir administered every 12 h did not maintain adequate plasma exposure when coadministered with rifampin.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/farmacocinética , Antituberculosos/administração & dosagem , Antituberculosos/farmacocinética , Infecções por HIV/tratamento farmacológico , Oligopeptídeos/administração & dosagem , Oligopeptídeos/farmacocinética , Piridinas/administração & dosagem , Piridinas/farmacocinética , Rifampina/administração & dosagem , Rifampina/farmacocinética , Tuberculose/tratamento farmacológico , Adolescente , Adulto , Fármacos Anti-HIV/efeitos adversos , Antituberculosos/efeitos adversos , Área Sob a Curva , Sulfato de Atazanavir , Biotransformação , Interações Medicamentosas , Feminino , Infecções por HIV/complicações , Meia-Vida , Humanos , Masculino , Pessoa de Meia-Idade , Oligopeptídeos/efeitos adversos , Piridinas/efeitos adversos , Rifampina/efeitos adversos , Tuberculose/complicações
11.
J Speech Lang Hear Res ; 49(5): 1127-46, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17077220

RESUMO

Speech-related changes in regional cerebral blood flow (rCBF) were measured using H(2)(15)O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest and during production of continuous narrative speech and whispered speech. Speech was recorded during scan acquisition for offline quantification of voice breaks, pitch breaks, and percentage aperiodicity to assess correlations between treatment-related changes in rCBF and clinical improvement. Results demonstrated that speech-related responses in heteromodal sensory areas were significantly reduced in persons with ADSD, compared with volunteers, before the administration of BTX. Three to 4 weeks after BTX injection, speech-related responses were significantly augmented in these regions and in left hemisphere motor areas commonly associated with oral-laryngeal motor control. This pattern of responses was most strongly correlated with the objective measures of clinical improvement (decreases in the frequency of voice breaks, pitch breaks, and percentage aperiodicity). These data suggest a pathophysiological model for ADSD in which BTX treatment results in more efficient cortical processing of sensory information, making this information available to motor areas that use it to more effectively regulate laryngeal movements.


Assuntos
Antidiscinéticos/farmacologia , Toxinas Botulínicas/farmacologia , Encéfalo/irrigação sanguínea , Tomografia por Emissão de Pósitrons/métodos , Fala/efeitos dos fármacos , Distúrbios da Voz/tratamento farmacológico , Adulto , Antidiscinéticos/uso terapêutico , Toxinas Botulínicas/uso terapêutico , Encéfalo/efeitos dos fármacos , Mapeamento Encefálico , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fonética , Fluxo Sanguíneo Regional/efeitos dos fármacos , Medida da Produção da Fala , Distúrbios da Voz/fisiopatologia
12.
Cereb Cortex ; 16(4): 587-95, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16049190

RESUMO

Neuroimaging studies of overt speech hold an important practical advantage allowing monitoring of subject performance, particularly valuable in disorders like aphasia. However, speech production is not a monotonic process but a complex sequence of stages. Levelt and colleagues have described these as roughly corresponding to two originally independent systems--conceptual and sensorimotor--that are linked in the formulation and expression of spoken language. In the initial stages a word is chosen to match a concept (lexical selection); in the later stages the sound and motor patterns are encoded and the word is uttered (articulation). It has been difficult to discriminate these stages using conventional neuroimaging techniques. We designed a functional magnetic resonance imaging study in an attempt to do this, by introducing a latency into a conventional naming paradigm, delaying the articulated response. Our results showed that left hemisphere perisylvian areas were active throughout, interacting with visual and heteromodal areas during early lexical access and with motor and auditory areas during overt articulation. These results are consistent with the broadest version of the Levelt model and with that derived from Chomsky's minimalist program in which a core language system interacts with conceptual-intentional systems and articulatory-perceptual systems during the early and late stages of lexical access respectively.


Assuntos
Córtex Cerebral/fisiologia , Formação de Conceito/fisiologia , Potenciais Evocados/fisiologia , Tempo de Reação/fisiologia , Semântica , Fala/fisiologia , Adulto , Mapeamento Encefálico , Humanos , Idioma , Imageamento por Ressonância Magnética , Masculino , Reconhecimento Visual de Modelos/fisiologia
13.
Hum Brain Mapp ; 27(8): 636-51, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16281285

RESUMO

Categorization is fundamental to our perception and understanding of the environment. However, little is known about the neural bases underlying the categorization of sounds. Using human functional magnetic resonance imaging (fMRI) we compared the brain responses to a category discrimination task with an auditory discrimination task using identical sets of sounds. Our stimuli differed along two dimensions: a speech-nonspeech dimension and a fast-slow temporal dynamics dimension. All stimuli activated regions in the primary and nonprimary auditory cortices in the temporal cortex and in the parietal and frontal cortices for the two tasks. When comparing the activation patterns for the category discrimination task to those for the auditory discrimination task, the results show that a core group of regions beyond the auditory cortices, including inferior and middle frontal gyri, dorsomedial frontal gyrus, and intraparietal sulcus, were preferentially activated for familiar speech categories and for novel nonspeech categories. These regions have been shown to play a role in working memory tasks by a number of studies. Additionally, the categorization of nonspeech sounds activated left middle frontal gyrus and right parietal cortex to a greater extent than did the categorization of speech sounds. Processing the temporal aspects of the stimuli had a greater impact on the left lateralization of the categorization network than did other factors, particularly in the inferior frontal gyrus, suggesting that there is no inherent left hemisphere advantage in the categorical processing of speech stimuli, or for the categorization task itself.


Assuntos
Córtex Auditivo/anatomia & histologia , Córtex Auditivo/fisiologia , Idioma , Percepção da Fala/fisiologia , Comportamento Verbal/fisiologia , Estimulação Acústica/métodos , Adulto , Feminino , Lobo Frontal/anatomia & histologia , Lobo Frontal/fisiologia , Lateralidade Funcional/fisiologia , Humanos , Testes de Linguagem , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Rede Nervosa/anatomia & histologia , Rede Nervosa/fisiologia , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Lobo Parietal/anatomia & histologia , Lobo Parietal/fisiologia , Tempo de Reação/fisiologia , Fatores de Tempo
14.
Clin Neuropharmacol ; 28(1): 18-27, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15711435

RESUMO

H2(15)O positron emission tomography (PET) was used to study the temporal course of central nervous system (CNS) responses to apomorphine in patients with idiopathic Parkinson disease (PD). Agonist-induced changes in regional cerebral blood flow (rCBF) were evaluated within corticostriatal-thalamocortical circuits as well as in regions that extend beyond the standard pathophysiological model for PD. Compared with controls, rCBF was increased in PD patients in subcortical regions including the basal ganglia and cerebellum and both increased and decreased in prefrontal, parietal, sensorimotor, and paralimbic cortical areas. Apomorphine reversed many of these effects and had widespread effects throughout the brain. We evaluated the effects of apomorphine as they changed over time, comparing rCBF before the motor response and at later times when the motor response was maximal. Apomorphine's effects on functional connectivity also changed over time; activity in the ventrolateral thalamus was coupled with that in the SMA and cerebellum at the time of maximum motor response, but not at 45 seconds. Apomorphine affected rCBF in regions commonly considered part of the pathophysiological model of PD (eg, basal ganglia, thalamus, SMA), and other effects were seen in regions outside of the model (eg, cerebellum and superior parietal lobule). Results are discussed in light of this model.


Assuntos
Apomorfina/administração & dosagem , Encéfalo/efeitos dos fármacos , Radioisótopos de Oxigênio , Doença de Parkinson/tratamento farmacológico , Tomografia por Emissão de Pósitrons/métodos , Adulto , Idoso , Encéfalo/irrigação sanguínea , Encéfalo/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/metabolismo , Fatores de Tempo
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