Cerebral ischemia is the principal cause of morbidity and mortality worldwide. In addition to neuronal loss associated with hypoxic-ischemic damage, cerebral ischemia is characterized by a neuromicrovascular injury. Nitrative stress and lipid peroxidation increase in hypoxic-ischemic damages and play an essential role in neuromicrovascular injury leading to cerebral ischemia. We hypothesized that newly described lipid peroxidation products, termed trans-arachidonic acids (TAA), could be implicated in the pathogenesis of hypoxia-ischemia by affecting the cerebral vasomotricity and microvascular integrity. / The effects of TAA on neuromicrovascular tone were tested ex vivo by monitoring the changes in vascular diameter of rat cerebral pial microvessels. Four isomers of TAA, namely 5 E-AA, 8E-AA, IIE-AA and 14 E-AA induced an endothelium-dependent vasorelaxation. Possible mechanisms involved in TAA-induced vasorelaxation were thoroughly investigated. Collectively, data enclosed revealed that TAA induce cerebral vasorelaxation through the interactive activation of BKCa channels with heme oxygenase-2. This interaction leads to generation of carbon monoxide which in turn activates soluble guanylate cyclase and triggers vasorelaxation. / Chronic effects of TAA on microvascular integrity were examined by generating a unilateral hypoxic-ischemic (HI) model of cerebral ischemia on newborn rat pups. Our HI model showed microvascular degeneration as early as 24h post-HI, preceded by an increase in cerebral TAA levels. HI-induced microvascular lesions were dependent on nitric oxide synthase activation and ensued TAA formation. Although the molecular mechanisms leading to TAA-induced microvascular degeneration were, in part uncovered for the retina, the primary site of action of TAA remains unknown. We demonstrated that TAA binds and activates GPR40 receptor, a newly described free fatty acid receptor. Importantly, GPR40 receptor knock-out prevents TAA-induced reduction in cerebral microvascular density and limits HI-induced brain infarct.

Galvos smegenų pilnavertiškam funkcionavimui turi būti palaikoma optimali galvos smegenų kraujotaka ir įsotinimas deguonimi. Darbo tikslas - nustatyti ir palyginti galvos smegenų kraujotakos pokyčius neurochirurginių operacijų metu naudojant sevofluraną ir propofolį. Mokslinio darbo tikslui pasiekti nustatyti uždaviniai: nustatyti galvos smegenų kraujotakos pokyčius transkranijiniu ultragarsiniu doplerografu matuojant vidurinės smegenų arterijos kraujo tėkmės greitį viršpadangtinių galvos smegenų navikų ir galvos smegenų arterinių aneurizmų operacijų metu bei operuojant ligonius, neturinčius galvos smegenų susirgimų (kontrolinė grupė); palyginti galvos smegenų kraujotakos pokyčius viršpadangtinių galvos smegenų navikų šalinimo operacijų metu naudojant sevofluraną ir propofolį; palyginti galvos smegenų kraujotakos pokyčius sevoflurano anestezijoje atliekant galvos smegenų navikų šalinimo, arterinių aneurizmų išjungimo operacijas ir operuojant ligonius, neturinčius galvos smegenų susirgimų (kontrolinė grupė); nustatyti ir palyginti sisteminės kraujotakos pokyčius bei įvertinti ir palyginti ligonių būklę po neurochirurginių operacijų naudojant sevofluraną ir propofolį. Klinikinio tyrimo metu ištirta 260 ligonnių. Nustatyta, kad bendrosios anestezijos palaikymui, atliekant neurochirurgines operacijas, sevofluranas gali būti naudojamas taip pat saugiai, kaip ir propofolis. Sevofluranas, naudojamas dozėmis iki 2,0 proc. tūrio iškvėpiamose dujose chirurginiam anestezijos gyliui... [toliau žr. visą tekstą] / Optimal cerebrovascular circulation and oxygen saturation must be maintained for full cerebral functioning. The aim of the study is to determine the changes of the cerebral circulation during supratentorial tumour resection or cerebral arterial aneurysm clipping surgery under sevoflurane and propofol anaesthesia. The following objectives were established: to determine and evaluate changes of the cerebral circulation by measurements of cerebral blood flow velocity in the middle cerebral artery using transcranial Doppler ultrasonography during supratentorial brain tumour resection or cerebral arterial aneurysm clipping surgery or operations for patients without cerebral pathology (control group); to compare the changes of the cerebral circulation during supratentorial brain tumour resection surgery under sevoflurane and propofol anaesthesia; to compare the changes of the cerebral circulation during supratentorial brain tumour resection, cerebral arterial aneurysm clipping or operations for patients without cerebral pathology (control group) under sevoflurane anaesthesia; to determine and compare the changes of the systemic hemodynamic during neurosurgery under sevoflurane and propofol anaesthesia; to determine and compare recovery period after sevoflurane and propofol anaesthesia.After giving written informed consent 260 eligible patients were enrolled in the study. The obtained results showed, that sevoflurane can be used as safely as propofol for maintaining general... [to full text]

Introdução: A hipertensão arterial é uma doença crônica com alta prevalência na população e, se não tratada, está relacionada a complicações cardiovasculares graves incluindo insuficiência renal, doença arterial coronária e acidente vascular cerebral. A associação entre os valores de pressão arterial (PA) e o desempenho cognitivo, tanto em pessoas adultas hipertensas quanto normotensas também tem sido demonstrada, e a hipertensão arterial é um importante fator de risco para a ocorrência de demência vascular. No entanto, a relação entre a gravidade da hipertensão, suas alterações vasculares e o déficit cognitivo é pouco conhecida. Objetivo: avaliar as alterações de função cognitiva em pacientes com hipertensão arterial de diferentes estágios e suas correlações com as propriedades arteriais funcionais e estruturais avaliadas por métodos não invasivos e com a circulação cerebral avaliada pelo Doppler transcraniano. Métodos: Trata-se de um estudo transversal em pacientes com hipertensão arterial seguidos na unidade de hipertensão arterial do Incor e um grupo de controles normotensos. Os pacientes foram divididos em três grupos: normotensão, hipertensão estágio-1 e hipertensão estágio-2. Os pacientes foram submetidos aos seguintes procedimentos: avaliação da rigidez arterial pela medida da velocidade de onda de pulso, medida da espessura da íntima média das artérias carótidas e da pressão central não invasiva, avaliação do fluxo cerebral pelo Doppler transcraniano e testes para a avaliação da função cognitiva. Resultados: Foram incluídos 221 indivíduos (150 hipertensos e 71 normotensos) por um período de 24 meses. Comparado com os indivíduos normotensos, a disfunção cognitiva é mais frequente nos pacientes com hipertensão arterial e está diretamente relacionada com a gravidade da doença. Os pacientes com hipertensão tiveram maior rigidez arterial, menor resposta de vasorreatividade cerebral e pior desempenho cognitivo. Conclusão: As alterações da função cognitiva são mais frequentes nos pacientes com hipertensão arterial e se relacionaram com a gravidade da doença. Os pacientes hipertensos têm maiores alterações vasculares que se associaram com pior desempenho cognitivo / Introduction: Hypertension is a high prevalent chronic disease in the population and, if not treated, is related to severe cardiovascular complications including stroke, renal failure and coronary artery disease. The association between blood pressure (BP) values and cognitive performance both in hypertensive and normotensive adults have been shown and hypertension is an important risk factor for occurrence of vascular dementia. However, the relationship between the hypertension severity, their vascular changes and cognitive impairment is less studied. Objective: to evaluate the cognitive function changes in patients with hypertension at different stages and their correlations with functional and structural arterial proprieties changes evaluated by non-invasive methods and with cerebral blood flow evaluated by transcranial Doppler. Methods: It is cross-sectional study in patients with hypertension followed at the hypertension unit of the Heart Institute (Incor) and a control normotensive group. Patients were divided into three groups: normotension, hypertension stage-1 and hypertension stage-2. All patients were undergone to the following procedures: arterial stiffness evaluation by pulse wave velocity, intima media thickness measurement of the carotids arteries and the noninvasive central blood pressure, cerebral blood flow evaluated by Transcranial Doppler and tests for cognitive function evaluation. Results: There were included 221 individuals (150 hypertensives and 71 normotensives) during a period of 24 months. Compared to normotensive individuals, cognitive impairment is more frequent in patients with hypertension and it is proportionally greater with the hypertension severity. Patients with hypertension have greater vascular changes, lower cerebral vasoreactivity response and worse cognitive performance. Conclusion: Cognitive function changes are frequent in hypertensive patients and are related to the severity of the disease. Hypertensive patients have greater vascular changes that were associated to worse cognitive performance

No description available.

No description available.

BACKGROUND: The potential pathogenesis between the presence and severity of chronic cerebrospinal venous insufficiency (CCSVI) and its relation to clinical and imaging outcomes in brain parenchyma of multiple sclerosis (MS) patients has not yet been elucidated. The aim of the study was to investigate the relationship between CCSVI, and altered brain parenchyma venous vasculature visibility (VVV) on susceptibility-weighted imaging (SWI) in patients with MS and in sex- and age-matched healthy controls (HC). METHODS: 59 MS patients, 41 relapsing-remitting and 18 secondary-progressive, and 33 HC were imaged on a 3T GE scanner using pre- and post-contrast SWI venography. The presence and severity of CCSVI was determined using extra-cranial and trans-cranial Doppler criteria. Apparent total venous volume (ATVV), venous intracranial fraction (VIF) and average distance-from-vein (DFV) were calculated for various vein mean diameter categories: < .3 mm, .3-.6 mm, .6-.9 mm and > .9 mm. RESULTS: CCSVI criteria were fulfilled in 79.7% of MS patients and 18.2% of HC (p < .0001). Patients with MS showed decreased overall ATVV, ATVV of veins with a diameter < .3 mm, and increased DFV compared to HC (all p < .0001). Subjects diagnosed with CCSVI had significantly increased DFV (p < .0001), decreased overall ATVV and ATVV of veins with a diameter < .3 mm (p < .003) compared to subjects without CCSVI. The severity of CCSVI was significantly related to decreased VVV in MS (p < .0001) on pre- and post-contrast SWI, but not in HC. CONCLUSIONS: MS patients with higher number of venous stenoses, indicative of CCSVI severity, showed significantly decreased venous vasculature in the brain parenchyma. The pathogenesis of these findings has to be further investigated, but they suggest that reduced metabolism and morphological changes of venous vasculature may be taking place in patients with MS.

Einleitung: Die Vena jugularis interna (VJI) gilt als das wichtigste Gefäß der zerebralen Drainage. Es gibt jedoch Hinweise darauf, dass das vertebrale Venensystem in Abhängigkeit von der Körperposition, an der zerebralen venösen Drainage beteiligt ist. Im Rahmen dieser Arbeit soll die Bedeutung der VJI und des vertebralen Venensystems für die zerebralvenöse Drainage in unterschiedlichen Körperpositionen untersucht werden. Methode: Bei 23 gesunden Probanden wurde der Blutfluss in den VJI und den Vv. vertebrales (VV) duplexsonographisch bestimmt. Dazu wurde die Person auf einem Kipptisch gelagert. Die Messungen wurden in den Positionen -15° (Kopftieflage), 0° (horizontal), 15°, 30°, 45°, und 90° (Stehen) durchgeführt. Der arterielle zerebrale Blutfluss (CBFA) wurde in den Positionen 0° und 45° bestimmt. Ergebnisse: Der Blutfluss der VJI ging von 810 ? 360 ml/min in Kopftieflage (-15°) auf 70 ? 100 ml/min im Stehen zurück. Gleichzeitig stieg der Blutfluss VV von 20 ? 15 ml/min in Kopftieflage auf 210 ? 120 ml/min im Stehen an. Der CBFA betrug 800 ? 153 ml/min in der 0°-Position und 720 ? 105 ml/min in der 45°-Position. Diskussion: Es konnte eine deutliche Lageabhängigkeit der zerebralvenösen Drainage nachgewiesen werden. Es zeigte sich, dass die zentrale Bedeutung der VJI für die zerebrale venöse Drainage auf die liegende Position beschränkt ist. Im Stehen verläuft die zerebrale venöse Drainage weitgehend über das vertebrale Venensystem. / Background: The internal jugular veins (IJV) are considered to be the main outflow of cerebral venous blood. However, there is evidence that the vertebral venous system also forms part of the cerebral venous outflow, depending on the position of the body. This paper asseses the hemodynamic consequences of postural changes in cerebral venous drainage by color-coded duplex sonography. Methods: Volume-blood-flow-measurements were conducted in 23 healthy volunteers in supine position on a tilt table. Both IJV and VV were studied in -15° (head-down tilt), 0°, 15°, 30°, 45°, and 90° (upright position) tilt. Arterial cerebral blood flow (CBFA) was measured in 0° and 45°-position. Results: Bloodflow in the IJV dropped from 810 ? 360 ml/min in the head-down-position (-15°) to 70 ? 100 ml/min at 90°. Simultaneously blood flow in the VV increased from 20 ? 15 ml/min in -15°-position to 210 ? 120 ml/min in the 90°-position. Discussion: The results show, that the cerebral blood drainage pathways depend heavily on the inclination of the body. The role of the IJV as the main drainage pathway of the cerebral blood appears to be confined to the supine position. In the erect position, the vertebral venous system was found to be the major outflow pathway in humans.

No description available.

In this report, we evaluate the role of visual areas responsive to motion in the human brain in the perception of stimulus speed. We first identified and localized V1, V3A, and V5/MT+ in individual participants on the basis of blood oxygenation level-dependent responses obtained in retinotopic mapping experiments and responses to moving gratings. Repetitive transcranial magnetic stimulation (rTMS) was then used to disrupt the normal functioning of the previously localized visual areas in each participant. During the rTMS application, participants were required to perform delayed discrimination of the speed of drifting or spatial frequency of static gratings. The application of rTMS to areas V5/MT and V3A induced a subjective slowing of visual stimuli and (often) caused increases in speed discrimination thresholds. Deficits in spatial frequency discrimination were not observed for applications of rTMS to V3A or V5/MT+. The induced deficits in speed perception were also specific to the cortical site of TMS delivery. The application of TMS to regions of the cortex adjacent to V5/MT and V3A, as well as to area V1, produced no deficits in speed perception. These results suggest that, in addition to area V5/MT+, V3A plays an important role in a cortical network that underpins the perception of stimulus speed in the human brain.

BACKGROUND: Magnetic resonance imaging and echo color Doppler (ECD) scan techniques do not accurately assess the cerebral venous return. This generated considerable scientific controversy linked with the diagnosis of a vascular syndrome known as chronic cerebrospinal venous insufficiency (CCSVI) characterized by restricted venous outflow from the brain. The purpose of this study was to assess the cerebral venous return in relation to the change in position by means of a novel cervical plethysmography method. METHODS: This was a single-center, cross-sectional, blinded case-control study conducted at the Vascular Diseases Center, University of Ferrara, Italy. The study involved 40 healthy controls (HCs; 18 women and 22 men) with a mean age of 41.5 +/- 14.4 years, and 44 patients with multiple sclerosis (MS; 25 women and 19 men) with a mean age of 41.0 +/- 12.1 years. All participants were previously scanned using ECD sonography, and further subset in HC (CCSVI negative at ECD) and CCSVI groups. Subjects blindly underwent cervical plethysmography, tipping them from the upright (90 degrees ) to supine position (0 degrees ) in a chair. Once the blood volume stabilized, they were returned to the upright position, allowing blood to drain from the neck. We measured venous volume (VV), filling time (FT), filling gradient (FG) required to achieve 90% of VV, residual volume (RV), emptying time (ET), and emptying gradient (EG) required to achieve 90% of emptying volume (EV) where EV = VV - RV, also analyzing the considered parameters by receiver operating characteristic (ROC) curves and principal component mathematical analysis. RESULTS: The rate at which venous blood discharged in the vertical position (EG) was significantly faster in the controls (2.73 mL/second +/- 1.63) compared with the patients with CCSVI (1.73 mL/second +/- 0.94; P = .001). In addition, respectively, in controls and in patients with CCSVI, the following parameters were highly significantly different: FT 5.81 +/- 1.99 seconds vs 4.45 +/- 2.16 seconds (P = .003); FG 0.92 +/- 0.45 mL/second vs 1.50 +/- 0.85 mL/second (P < .001); RV 0.54 +/- 1.31 mL vs 1.37 +/- 1.34 mL (P = .005); ET 1.84 +/- 0.54 seconds vs 2.66 +/- 0.95 seconds (P < .001). Mathematical analysis demonstrated a higher variability of the dynamic process of cerebral venous return in CCSVI. Finally, ROC analysis demonstrated a good sensitivity of the proposed test with a percent concordant 83.8, discordant 16.0, tied 0.2 (C = 0.839). CONCLUSIONS: Cerebral venous return characteristics of the patients with CCSVI were markedly different from those of the controls. In addition, our results suggest that cervical plethysmography has great potential as an inexpensive screening device and as a postoperative monitoring tool.