Navegando por Palavras-chave "Cerebral blood flow"
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- ItemSomente MetadadadosThe A(1) receptor agonist R-Pia reduces the imbalance between cerebral glucose metabolism and blood flow during status epilepticus: Could this mechanism be involved with neuroprotection?(Elsevier B.V., 2011-01-01) Silva, Lara Ribeiro [UNIFESP]; Nehlig, Astrid; Rosim, Fernanda Elisa [UNIFESP]; Vignoli, Thiago [UNIFESP]; Persike, Daniele Suzete [UNIFESP]; Ferrandon, Arielle; Sinigaglia-Coimbra, Rita [UNIFESP]; Silva Fernandes, Maria Jose da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ StrasbourgIt is well known that the uncoupling between local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF), i.e. decrease in LCBF rates with high LCGU, is frequently associated with seizure-induced neuronal damage. This study was performed to assess if the neuroprotective effect of the adenosinergic A(1) receptor agonist R-N-phenylisopropyladenosine (R-Pia) injected prior to pilocarpine is able to reduce the uncoupling between LCGU and LCBF during status epilepticus (SE). Four groups of rats were studied: Saline, Pilo, R-Pia + Saline and R-Pia + Pilo. for LCGU and LCBF studies, rats were subjected to autoradiography using [C-14]-2-deoxyglucose and [C-14]-iodoantypirine, respectively. Radioligands were injected 4 h after SE onset. Neuronal loss was evaluated by Fluorojade-B (FJB) at two time points after SE onset (24 h and 7 days). the results showed a significant increase in LCGU in almost all brain regions studied in the Pilo and R-Pia + Pilo groups compared to controls. However, in R-Pia pretreated rats, the uncoupling between LCGU and LCBF was moderated in a limited number of structures as substantia nigra pars reticulata and hippocampal formation rather in favor of hyperperfusion. Significant increases in LCBF were observed in the entorhinal cortex, thalamic nuclei, mammillary body, red nucleus, zona incerta, pontine nucleus and visual cortex. the neuroprotective effect of R-Pia assessed by FJB showed a lower density of degenerating cells in the hippocampal formation, piriform cortex and basolateral amygdala. in conclusion our data shows that the neuroprotective effect of R-Pia was accompanied by a compensatory metabolic input in brain areas involved with seizures generation. Published by Elsevier Inc.
- ItemSomente MetadadadosCerebral microvascular blood flow and CO2 reactivity in pulmonary arterial hypertension(Elsevier Science Bv, 2016) Treptow, Erika [UNIFESP]; Oliveira, Mayron Faria [UNIFESP]; Soares, Aline [UNIFESP]; Ramos, Roberta Pulcheri [UNIFESP]; Medina, Luiz [UNIFESP]; Lima, Rita [UNIFESP]; Alencar, Maria Clara [UNIFESP]; Ferreira, Eloara Vieira [UNIFESP]; Ota-Arakaki, Jaquelina Sonoe [UNIFESP]; Tufik, Sergio [UNIFESP]; Nery, Luiz Eduardo [UNIFESP]; Bittencourt, Lia Rita Azeredo [UNIFESP]; Neder, Jose Alberto [UNIFESP]Hypocapnia and endothelial dysfunction might impair microvascular cerebral blood flow (CBFmicr) and cerebrovascular reactivity to CO2 (CVRCO2). Pulmonary arterial hypertension (PAH) is characteristically associated with chronic alveolar hyperventilation and microvascular endothelial dysfunction. We therefore determined CBFmicr (pre-frontal blood flow index (BFI) by the indocyanine green-near infrared spectroscopy methodology) during hypocapnia and hypercapnia in 25 PAH patients and 10 gender- and age-matched controls. Cerebral BFI was lower in patients than controls at similar transcutaneous PCO2 (PtcCO(2)) levels in both testing conditions. In fact, while BFI increased from hypocapnia to hypercapnia in all controls, it failed to increase in 17/25 (68%) patients. Thus, BFI increased to a lesser extent from hypo to hypercapnia ("Delta") in patients, i.e., they showed lower Delta BFI/Delta PtcCO(2) ratios than controls. In conclusion, CBFmicr and CVRCO2 are lessened in clinically stable, mildly-impaired patients with PAH. These abnormalities might be associated with relevant clinical outcomes (hyperventilation and dyspnea, cognition, cerebrovascular disease) being potentially amenable to pharmacological treatment. (C) 2016 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosInfluence of blood viscosity to cerebral blood flow in older humans compared to young subjects(Elsevier B.V., 2012-01-01) Santos-Galduroz, Ruth F.; Bueno, Orlando F. A. [UNIFESP]; Yamaga, Lilian I.; Armani, Fernanda [UNIFESP]; Galduroz, Jose Carlos F. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Estadual Paulista; Universidade Federal do ABC (UFABC); Hosp Israelita Ezrah; Res Inst Albert EinsteinObjective: Since blood viscosity (BV) is one of the most important factors determining blood flow, this study aimed to investigate the possible correlation between increased blood viscosity and reduction of regional cerebral blood flow (rCBF) in healthy ageing.Methods: Male subjects were distributed in two groups: young, aged 20-30 (27 volunteers), or elderly, aged 60-70 (50 volunteers). Whole blood viscosity was obtained with a Wells-Brookfield Cone/Plate Viscometer. Cerebral blood flow was analysed by means of single photon emission computed tomography (SPECT).Results: the mean BV values were 3.28 +/- 0.43 mPa in the group of young volunteers and 4.33 +/- 0.73 mPa in the group of elderly volunteers (t = -6.9, p < 0.0001). the elderly had a lower blood flow than the young in the following regions: bilateral parietal; temporal-parietal and temporal of the left hemisphere. Pearson's correlation between BV and rCBF showed a good inverse correlation when the BV was above 3.95 +/- 0.83 mPa.Conclusions: Our results point to a close relationship between the two parameters analysed, BV and rCBF. the impairment in rCBF observed in the elderly volunteers might be due to an increase in BV, among other factors.Significance: These findings suggest interesting possibilities for the treatment/prevention of brain ageing. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.