Biomedical subjects

Tomoki Hashimoto

Publications and source records attributed to Tomoki Hashimoto.

22 records · Page 2Linked to original sources

PubMed2002

Characterization of the cerebral blood flow response to balloon deflation after temporary internal carotid artery test occlusion.

The authors tested the hypothesis that cerebral blood flow (CBF) would increase after acute and relatively brief internal carotid artery (ICA) test occlusion, and examined the relationship of the postdeflation CBF to the development of neurologic symptoms. In 16 patients undergoing ICA test occlusion with deliberate hypotension, the authors measured intracarotid 133Xe CBF at baseline, occlusion, and deflation. Four patients developed neurologic symptoms during occlusion. As positive controls, 11 other patients received intracarotid verapamil or papaverine before deflation as part of another protocol. Balloon occlusion was 23.1 +/- 10.5 minutes (mean +/- standard deviation) in duration. At 1.3 +/- 1.6 minutes after balloon deflation, there was a trend (12 +/- 31%) for CBF to increase (48 +/- 9 mL/100 g/min versus 53 +/- 17 mL/100 g/min, P =.15), and a 16 +/- 27% decrease in cerebrovascular resistance (CVR; 2.1 +/- 0.6 mm Hg/100 g/min/mL versus 1.7 +/- 0.6 mm Hg/100 g/min/mL, P =.03) compared with baseline values. By comparison, patients who received a intracarotid dilator demonstrated a 53 +/- 55% increase in CBF (48 +/- 10 mL/100/min versus 70 +/- 23 mL/100 g/min, P = .007) and a 33 +/- 31% decrease in CVR (2.2 +/- 0.6 mm Hg/100 g/min/mL versus 1.4 +/- 0.6 mm Hg/100 g/min/mL, P = .0007) compared with baseline. Analysis of variance and regression analysis showed no other relationships between postocclusion CBF and balloon occlusion duration, distal internal carotid occlusion ("stump") pressure, or the development of neurologic symptoms. Acute, temporary interruption of ICA blood flow resulted in minimal postocclusive changes in cerebrovascular hemodynamics, even in those patients who developed neurologic symptoms during the period of test occlusion.

Adult↗

PubMed2002

Increased cerebral blood flow after brain arteriovenous malformation resection is substantially independent of changes in cardiac output.

Brain arteriovenous malformation (BAVM) resection can result in an acute increase in cerebral blood flow (CBF) of unclear etiology. This observational study investigated the relationship between changes in CBF and cardiac output (CO) in patients undergoing microsurgical resection of BAVMs. In 20 patients undergoing a BAVM resection during an isoflurane-based anesthesia, we measured CBF and systemic cardiovascular parameters immediately before and after BAVM resection. CBF was measured on the hemisphere ipsilateral to the lesions and on the contralateral side, using intravenous cold 133Xe washout. Cardiac output was measured using thermodilution technique via a pulmonary artery catheter. There was an increase in global CBF after resection (25 +/- 8 versus 31 +/- 13 mL/100 g/min, preresection versus postresection, mean +/- SD, P =.002), ipsilateral CBF (25 +/- 8 versus 31 +/- 13 mL/100 g/min, P =.002), and contralateral CBF (24 +/- 7 versus 30 +/- 13 mL/100 g/min, P =.003). There was no change in CO, mean systemic arterial pressure, central venous pressure, or pulmonary artery diastolic pressure. The change in CBFGLOBAL was not correlated with changes in CO (r =.154, P =.517). BAVM resection resulted in global increases in CBF that was not substantially related to changes in CO or other systemic parameters.

Adult↗

PubMed2002

Relationship of nidal vessel radius and wall thickness to brain arteriovenous malformation hemorrhage.

Cerebral (brain) arteriovenous malformations (BAVMs) are a tangle of disorganized vessels that are a rare cause of hemorrhagic stroke in the general population. Although clinical presentation of hemorrhage may be related to the structure of BAVM vessels, there has been no systematic quantitative analysis of BAVM vessel morphology. Histological sections of excised BAVM lesions were prepared from patients who presented with hemorrhage (n = 14) and from patients with no history of hemorrhage (n = 22). Mean values of radius and wall thickness in each section were determined. BAVM radii were 422+/-136 microm (mean +/- SD), minimum wall thickness (thinnest portion of the wall) was 54+/-14 microm; and the minimum thickness/radius ratio was 0.23+/-0.07. Greater vessel wall thickness was associated with hemorrhagic presentation (OR= 1.1; p = 0.046) after adjusting for feeding artery pressure. Because BAVM vessels from patients presenting with hemorrhage had thicker vessel walls, the search for structural properties predisposing BAVM rupture should be expanded beyond the morphological properties analyzed here.

Adult↗

PubMedDate not supplied

Regulation of tie2 expression by angiopoietin--potential feedback system.

To study a potential feedback system in the angiopoietin (Ang)-Tie2 system, the authors examined effects of Ang1 and Ang2 on Tie2 expression on human umbilical vein endothelial cells (HUVECs) with or without stimulation by a potent inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). Ang1, but not Ang2, down-regulated Tie2 expression on HUVECs without TNF-alpha stimulation. Both Ang1 and Ang2 attenuated TNF-alpha-induced Tie2 up-regulation. Regulation of Tie2 expression by Ang1 or Ang2 was not dependent on phosphatidylinositol 3-kinase. The Ang-Tie2 system appears to have an autoregulatory feedback system that may be regulating the overall activity of the Tie2 system in both physiological and pathological conditions.

Angiopoietin-1↗