Cerebral blood flow regulation under activation of the primary somatosensory cortex during electrical stimulation of the forearm.

Coupling of neuronal activity to cerebral blood flow (CBF) is widely accepted, but the exact mechanism is still under investigation. We assessed the responses of CBF coupled with electrical activity over the primary somatosensory cortex (S-I) during electrical stimulation of the contralateral forearm in cats. CBF in S-I was monitored using laser-Doppler flowmetry (LDF), and electrical activity was recorded with a tungsten microelectrode.

Neural activation of the brain with hemodynamic insufficiency.

Little is known about how ischemia affects hemodynamic responses to neural activation in the brain. We compare the effects of a motor activation task and a cerebral vasodilating agent, acetazolamide (ACZ), on regional cerebral blood flow (rCBF) in primary sensorimotor cortex (PSM) in six patients with major cerebral artery steno-occlusive lesions without paresis of the upper extremities. Quantitative rCBF was measured in all patients using H2(15)O autoradiographic method and positron emission tomography.

[A case of hemangiopericytoma with multiple extracranial metastasis: a case report].

A case of a patient with hemangiopericytoma with multiple extracranial metastasis, who has survived for more than twenty years is reported. A fifty-five-year-old male presented brain tumor twenty years ago. He underwent total removal of the tumors, but recurrences occurred each time.

Human dural thickness measured by ultrasonographic method: reflection of intracranial pressure.

We measured changes in dural thickness to estimate intracranial pressure. The dural thickness on magnetic resonance imaging with contrast enhancement was compared in a hydrocephalic patient before and after shunt operation. Dural thickness also was measured directly using a micrometer at craniotomy for aneurysmal clipping in 11 patients.

Comparison of vasodilatory effect of carbon dioxide inhalation and intravenous acetazolamide on brain vasculature using positron emission tomography.

Carbon dioxide (CO2) and acetazolamide are increasingly being used as vasodilators to detect cerebrovascular reserve capacity in patients of chronic cerebrovascular disease. The functional cerebrovascular reserve or ability of cerebral vessels to lower their resistance in response to decrease in cerebral perfusion pressure is expressed as change in cerebral blood flow from baseline under a vasodilatory stimuli. Theoretically a vasodilator causing maximum vasodilation, and thereby expressing complete reserve capacity would be more suitable for such a purpose.

Magnetic resonance imaging quantitation of superior sagittal sinus flow: correlation to cerebral blood flow measured by xenon-enhanced computed tomography.

We compared measurements of venous blood flow velocity in the superior sagittal sinus (SSS) obtained by magnetic resonance imaging (MRI) and quantitative measurements of cerebral blood flow (CBF) obtained by xenon-enhanced CT, in neurosurgical patients and normal volunteers, to assess the clinical usefulness of MRI for determination of CBF. Flow measurements were obtained in 15 neurosurgical patients and 3 normal volunteers. SSS velocimetry was performed using the direct bolus imaging technique with a 1.

Responses of cerebral blood flow regulation to activation of the primary somatosensory cortex during electrical stimulation of the forearm.

We assessed the cerebral blood flow (CBF) response to electrical stimulation of the contralateral forearm over the primary somatosensory cortex (S-I) in anesthetized cats. CBF was monitored continuously using laser-Doppler flowmetry (LDF). In the first set of experiments, the effects of varying stimulus frequency and intensity were examined.

Induction of matrix metalloproteinases following brain injury in rats.

Matrix metalloproteinases (MMPs) are important in various pathophysiological processes related with the tissue remodeling. We planned the experiments to determine whether MMPs participate in disruption and repair of the tissue following brain injury. We have studied induction of MMP-9, a 92 kilodalton (kDa) gelatinase, in traumatic brain tissue, which may be produced by brain residual cells.

Assessment of vasoreactivity in brain edema by acetazolamide activation SPECT and PET.

Our study was performed to find out cerebrovascular reactivity post acetazolamide administration in patients with peritumoral edema. Adult patients (n = 9) underwent CBF measurement by 99mTc-HMPAO SPECT pre and post 1 gram i.v.

Effect of glycerol on blood flow distribution in tumoral and peritumoral brain tissue.

To evaluate the effect of glycerol, thirty-two patients with brain tumor were directed to the study, including 17 gliomas and 15 meningiomas. Blood flow before and after the administration of glycerol were measured with Xe CT. Glioma was significantly hypo-perfused.

Intercellular adhesion molecule-1 expression on glia following brain injury: participation of interleukin-1 beta.

Interleukin-1 (IL-1), one of the most important inflammatory cytokines, promotes glia to express intercellular adhesion molecule-1 (ICAM-1) in vitro. IL-1 is known to be produced in situ immediately after brain insults and recently we have found that glia, including astrocytes, express ICAM-1 in vivo following cortical stab wounds. To evaluate the participation of IL-1 beta in posttraumatic ICAM-1 expression on glia in vivo, we performed the following experiments.

Intraoperative laser flowmetry reflects levels of cerebral blood flow during neurosurgical procedures.

Changes in cerebral blood flow (CBF) during craniotomies (mean 62.2 years, n = 31) were studied using a laser flowmeter (LFM) to evaluate the utility in CBF monitoring. A small flat probe was applied to the brain surface near the surgical field.

Dynamics of cerebral blood flow and metabolism in patients with cranioplasty as evaluated by 133Xe CT and 31P magnetic resonance spectroscopy.

Objective: Prolonged improvement in neurological and mental disorders has been seen after only cranioplasty in patients initially treated with external decompression for high intracranial pressure. The objective was to evaluate, using 133Xe CT and 31P magnetic resonance spectroscopy (MRS), how restoring the bone itself can influence cerebral blood flow and cerebral energy metabolism after high intracranial pressure is attenuated.

Methods: Seven patients (45-65 years old) who had undergone external decompression to prevent uncontrollable intracranial hypertension after acute subarachnoid haemorrhage were evaluated.

Posterior communicating artery section during surgery for basilar tip aneurysm.

Although dividing the posterior communicating artery (PComA) during surgery has been criticized for increasing the risk of ischaemia, this procedure increase working space improving visibility and the ability to manipulate during treatment of basilar tip aneurysms via the pterional approach. We divided a hypoplastic PComA in 4 of our cases of basilar tip aneurysm. This was necessary because either (1) the length of the PComA and intracranial internal carotid artery (ICA) limited medial retraction of the ICA and access to the basilar bifurcation region, or (2) the PComA and its perforators ran just in front of the aneurysm, interfering with its exposure.

Changes in dural thickness reflect changes in intracranial pressure in dogs.

The thickness of the dura mater was obtained from ultrasound probes on the skull and fast Fourier transform-Cepstrum through a probability process at various intracranial pressures (ICP), measured with pressure transducers, in 12 anesthetized dogs. There was a constant relationship between changes in thickness (micron) and changes in ICP (mmHg) from 5 to 80 mmHg. The estimated thickness at 0 mmHg of pressure and values obtained from measurements of dural samples were very similar.

Changes in the cerebrocortical capillary network following venous sinus occlusion in cats.

Background: Although the important protective effect of venous collateral pathways in sinus occlusion on parenchymal injury has been demonstrated in previous works, the vascular response in the capillary microcirculation itself after cerebral venous occlusion has not been fully elucidated. We examined the morphology of the capillary network after venous occlusion by relating stereologic morphometric parameters to changes in local cerebral blood flow and the development of brain edema.

Methods: Experimental venous sinus occlusion was induced by injection of 0.

Effect of intracarotid administration of 6-aminonicotinamide on cerebral blood flow in cats.

Background And Purpose: We evaluated the effects of an adenosine triphosphate blocker, 6-aminonicotinamide (6-ANA), on the cerebral blood flow (CBF), cerebral metabolism, and electroencephalogram of cats.

Methods: Catheters were inserted into the common carotid artery of 16 adult cats anesthetized with ketamine via the lingual artery. We measured CBF in the infused area by the inhaled hydrogen gas clearance method and analyzed the electroencephalogram frequency.

Computerized tomography in the assessment of brain shifts in acute subdural hematoma.

Computed tomography (CT) was used to characterize brain shifts in 30 adult patients (mean age 51.9 years) with fatal supratentorial acute subdural hematomes (ASH) who were admitted within 3 hours of the head trauma. The Glasgow Coma Scale (GCS) score, hematoma width, and midline shift were tabulated.

Dynamics of cerebral metabolism in patients with chronic subdural hematoma evaluated with phosphorous 31 MR spectroscopy before and after surgery.

Purpose: To determine whether the depression of cerebral bioenergetic metabolism caused by chronic subdural hematomas can account for neurologic dysfunction and whether the degree of metabolic depression may be useful for clinical assessment and therapy.

Methods: Sixteen patients who had chronic subdural hematomas with hemiparesis and/or mental disturbances underwent phosphorous 31 MR spectroscopy before and 10 to 14 days after surgery. Phosphorous 31 MR spectroscopy was also performed on 5 patients who had chronic subdural hematomas with only slight headaches who were treated by conservative therapy and on 10 healthy volunteers.

Progression of kaolin-induced hydrocephalus and changes in performance of operant tasks by rats.

The behavior of rats with progressive hydrocephalus was examined to detect early neurological deterioration. Kaolin solution was injected into the cisterna magna of 10 of 17 anesthetized 8-week-old male rats (day 0), and saline in the other 7 rats (control group). Reaction time (RT, sec) and error ratio (ER, %) of unanesthetized rats escaping from electrical stimuli toward a nonstimulated sheet within a box were recorded daily from day 4 until autopsy after 4 weeks.

An assessment of progression of brain edema with amino acid levels in cerebrospinal fluid and changes in electroencephalogram in an adult cat model of cold brain injury.

We investigated the relationship between the changes of the electroencephalogram (EEG) and concentration of amino acids (AAs) in cerebrospinal fluid (CSF) using a model of cold brain injury. A cold injury was made over the motor area of anesthetized adult cats (n = 45). The AAs in CSF from cisterna magna and in the blood were assayed by liquid chromatography.

A trans-orofacial approach for the removal of an extracranial meningioma in the skull base.

Two rare cases of extracranial meningiomas associated with intracranial masses are reported. From the roentgenological findings both of the tumors were regarded as being partly connected. The tumors were surgically treated 21 and 19 years, respectively, after the first removal of the intracranial masses.

Microcirculation in experimental brain oedema assessed by laser-Doppler flowmetry.

Continuous measurement of CBV and CBF by means of laser-Doppler flowmetry was performed to analyse the cerebrovascular response to water accumulation during brain infusion oedema in cats. The presence of an oedema generator elicits a continuous reduction of CBV and a transient reduction of CBF. With cessation of this mechanical force of oedema production, CBV and CBF returned to control levels.

Fastigial pressor response observed during an operation on a patient with cerebellar bleeding--an anatomical review and clinical significance.

The fastigial pressor response (FPR) consists of an abrupt rise in blood pressure and tachycardia with hyperpneic response. The FPR is an important sign in posterior fossa surgery for respiration in postoperative patients. The authors experienced a distinct pressor, tachycardiac, and hyperpneic response elicited when controlling bleeding using a bipolar coagulator forceps at the subfastigial white matter in a 72-year-old man with cerebellar hemorrhage.