Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Magn Reson Med ; 90(6): 2432-2442, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37427535

RESUMO

PURPOSE: [13 C]Bicarbonate formation from hyperpolarized [1-13 C]pyruvate via pyruvate dehydrogenase, a key regulatory enzyme, represents the cerebral oxidation of pyruvate and the integrity of mitochondrial function. The present study is to characterize the chronology of cerebral mitochondrial metabolism during secondary injury associated with acute traumatic brain injury (TBI) by longitudinally monitoring [13 C]bicarbonate production from hyperpolarized [1-13 C]pyruvate in rodents. METHODS: Male Wistar rats were randomly assigned to undergo a controlled-cortical impact (CCI, n = 31) or sham surgery (n = 22). Seventeen of the CCI and 9 of the sham rats longitudinally underwent a 1 H/13 C-integrated MR protocol that includes a bolus injection of hyperpolarized [1-13 C]pyruvate at 0 (2 h), 1, 2, 5, and 10 days post-surgery. Separate CCI and sham rats were used for histological validation and enzyme assays. RESULTS: In addition to elevated lactate, we observed significantly reduced bicarbonate production in the injured site. Unlike the immediate appearance of hyperintensity on T2 -weighted MRI, the contrast of bicarbonate signals between the injured region and the contralateral brain peaked at 24 h post-injury, then fully recovered to the normal level at day 10. A subset of TBI rats demonstrated markedly increased bicarbonate in normal-appearing contralateral brain regions post-injury. CONCLUSION: This study demonstrates that aberrant mitochondrial metabolism occurring in acute TBI can be monitored by detecting [13 C]bicarbonate production from hyperpolarized [1-13 C]pyruvate, suggesting that [13 C]bicarbonate is a sensitive in-vivo biomarker of the secondary injury processes.


Assuntos
Lesões Encefálicas Traumáticas , Lesões Encefálicas , Ratos , Masculino , Animais , Ácido Pirúvico/metabolismo , Bicarbonatos/metabolismo , Ratos Wistar , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Mitocôndrias/metabolismo , Isótopos de Carbono
2.
Cerebellum ; 9(3): 398-404, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20461489

RESUMO

Early after stroke, there is loss of intracortical facilitation (ICF) and increase in short-interval intracortical inhibition (SICI) in the primary motor cortex (M1) contralateral to a cerebellar infarct. Our goal was to investigate intracortical M1 function in the chronic stage following cerebellar infarcts (>4 months). We measured resting motor threshold (rMT), SICI, ICF, and ratios between motor-evoked potential amplitudes (MEP) and supramaximal M response amplitudes (MEP/M; %), after transcranial magnetic stimulation was applied to the M1 contralateral (M1(contralesional)) and ipsilateral (M1(ipsilesional)) to the cerebellar infarct in patients and to both M1s of healthy age-matched volunteers. SICI was decreased in M1(contralesional) compared to M1(ipsilesional) in the patient group in the absence of side-to-side differences in controls. There were no significant interhemispheric or between-group differences in rMT, ICF, or MEP/M (%). Our results document disinhibition of M1(contralesional) in the chronic phase after cerebellar stroke.


Assuntos
Infarto Encefálico/fisiopatologia , Doenças Cerebelares/fisiopatologia , Lateralidade Funcional/fisiologia , Córtex Motor/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Adulto , Potencial Evocado Motor , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Magnética Transcraniana , Adulto Jovem
3.
Radiographics ; 27(5): 1401-17, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17848699

RESUMO

Liver transplantation is currently an accepted first-line treatment for patients with end-stage acute or chronic liver disease, but postoperative complications may limit the long-term success of transplantation. The most common and most clinically significant complications are arterial and venous thrombosis and stenosis, biliary disorders, fluid collections, neoplasms, and graft rejection. Early diagnosis is crucial to the successful management of all these complications, and imaging plays an important role in the diagnosis of all but graft rejection. A multimodality approach including ultrasonography and cross-sectional imaging studies often is most effective for diagnosis. Each imaging modality has specific strengths and weaknesses, and the diagnostic usefulness of a modality depends mainly on the patient's characteristics, the clinical purpose of the imaging evaluation, and the expertise of imaging professionals.


Assuntos
Doenças dos Ductos Biliares/diagnóstico , Síndrome de Budd-Chiari/diagnóstico , Diagnóstico por Imagem/métodos , Rejeição de Enxerto/diagnóstico , Neoplasias Hepáticas/diagnóstico , Transplante de Fígado/efeitos adversos , Adulto , Doenças dos Ductos Biliares/etiologia , Síndrome de Budd-Chiari/etiologia , Feminino , Rejeição de Enxerto/etiologia , Humanos , Neoplasias Hepáticas/etiologia , Transplante de Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Padrões de Prática Médica , Ultrassonografia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA