bluuebunny/crossref_metadata_2025_split huggingface dataset:
The long-latency component of cerebral evoked potentials in anesthetized cats
Authors: Lee Kyu Ho , Kim Jun , Chung Jin Mo 
Published: May 2009

✓ A late component of the cortical evoked potential elicited by somatosensory afferent input was studied in cats anesthetized with α-chloralose. Cortical evoked potentials were recorded from the somatosensory-motor cortex during stimulation of the sural nerve with graded intensities. The stimulus intensity was adjusted to activate Aαβ fibers only, then both Aαβ and Aδ fibers, and both A and C fibers, as judged by afferent volleys monitored from the sural nerve proximal to the stimulating site. In addition to early components reported previously, a very late component was identified at a latency of 400 to 600 msec following stimulation of the sural nerve with intensities above threshold for Aδ fibers. A further increase in stimulation intensity to include activation of C fibers did not reveal any more components. This late component was depressed by a systemic intravenous injection of morphine (2 mg/kg), and intravenous naloxone (0.1 mg/kg) reversed the effect of morphine. The late component of the evoked potential could also be recorded from subcortical tissue after decortication of the sensorimotor cortex.
From these results, it appears that a very late component of the cortical evoked potential can be recorded from cats anesthetized with α-chloralose. The late component is evoked by activation of peripheral Aδ fibers. Furthermore, its morphine sensitivity suggests that this component may be elicited by nociceptive afferent fibers. If further investigations prove this, the late component, which is analogous to human long-latency potentials, could be used in an experimental model for pain research.
Internal carotid artery stump angioplasty for the treatment of cerebrovascular occlusive disease
Authors: Benzel Edward C. , Sittig Kevin M. , Mirfakhraee Mansour 
Published: May 2009

✓ Nineteen patients underwent a total of 21 stump angioplasty procedures for an occluded internal carotid artery. Indications for surgery included the preparation of the donor vessel for a subsequent extracranial-intracranial bypass procedure, the occurrence of emboli to the intracranial vasculature from the external carotid artery circulation, and the association with symptomatic occlusive disease of the external carotid artery accompanying occlusion of the ipsilateral internal carotid artery.
The technique utilized and the results obtained in these 19 patients are presented. In select patients, the removal of an occluded internal carotid artery stump via a stump angioplasty is beneficial in preventing the catastrophic sequela of embolic cerebrovascular disease.
A proposed grading system for arteriovenous malformations
Authors: Spetzler Robert F. , Martin Neil A. 
Published: May 2009

✓ An important factor in making a recommendation for treatment of a patient with arteriovenous malformation (AVM) is to estimate the risk of surgery for that patient. A simple, broadly applicable grading system that is designed to predict the risk of morbidity and mortality attending the operative treatment of specific AVM's is proposed. The lesion is graded on the basis of size, pattern of venous drainage, and neurological eloquence of adjacent brain. All AVM's fall into one of six grades. Grade I malformations are small, superficial, and located in non-eloquent cortex; Grade V lesions are large, deep, and situated in neurologically critical areas; and Grade VI lesions are essentially inoperable AVM's.
Retrospective application of this grading scheme to a series of surgically excised AVM's has demonstrated its correlation with the incidence of postoperative neurological complications. The application of a standardized grading scheme will enable a comparison of results between various clinical series and between different treatment techniques, and will assist in the process of management decision-making.
Duration versus degree of hypotension as critical conditions of brain infarction in the albino rat
Authors: Laas Rudolf , Jahn Bernd , Kessler Kay 
Published: May 2009

✓ In 41 anesthetized, spontaneously breathing male adult albino rats, cerebral hypotension of precisely defined duration and magnitude was induced by means of controlled arterial hemorrhage. One common carotid artery was occluded throughout the hypotensive period, and the target pressure was monitored in the ipsilateral internal carotid artery. Regional brain infarcts developed in all 16 animals with a target pressure of 14 mm Hg maintained for 90 minutes and in all five animals with a target pressure of 12 mm Hg maintained for 70 minutes. However, the brains of all 10 rats with a target pressure of 17 mm Hg maintained for 80 minutes remained intact. In two further groups of five animals each with target pressures of 15 mm Hg for 80 minutes and 16 mm Hg for 90 minutes the incidence of infarct was about 30%. There were no marked differences between the five groups of rats in body weight, body temperature, heart rate, respiratory rate, PaO2, PaCO2, arterial pH, or hematocrit.
The data suggest that, in the rat, the clear-cut threshold for the induction of brain infarcts is a function of the severity and duration of arterial hypotension. Evidence is presented indicating that this function is distinctly species-dependent, due to species differences in the dilatory capacity of the arteries supplying the brain rather than species differences in brain vulnerability.
Cerebral protection
Authors: Hoff Julian T. 
Published: May 2009

✓ Cerebral protection from an ischemic/hypoxic insult implies that tissue injury can be controlled or even prevented by certain therapeutic maneuvers. For example, physiological thresholds may be altered so that tissue vulnerability to the insult is reduced, or the intensity of an insult may be blunted by enhancing brain homeostasis. Such a therapeutic maneuver is carotid endarterectomy to improve blood flow in the disordered hemisphere. Alternatively, drugs with protective properties can be used before or even after the insult to “stabilize” injured tissue and prevent the harmful secondary effects that often follow.
Various past and present approaches to cerebral protection employing physiological, pharmacological, and surgical intervention are reviewed. The mechanisms by which each allegedly protects the brain from ischemia and hypoxia are discussed briefly. Promising, but not always successful, approaches used in the past have pointed the way for new and more rational therapies. Truly effective protection of the brain from ischemia and hypoxia depends directly upon our capability to explore basic mechanisms of injury and our willingness to measure accurately and objectively the outcome of newly developed protective measures.
Intracranial malignant lymphoma
Authors: Jiddane Mohamed , Nicoli François , Diaz Pédro , Bergvall Ulf , Vincentelli François , Hassoun Jacques , Salamon Georges 
Published: May 2009

✓ Although primary malignant lymphoma is a rare entity in the gamut of intracranial tumors, it is more frequently seen than the secondary intracranial spread of a primary extracranial lymphoma. In general, the occurrence of lymphomas seems to be provoked by immunosuppression, as with medication (predominantly after transplantation) or with immunodepressive disease such as acquired immunodeficiency syndrome (AIDS). The usual age of onset of this disease is 55 to 65 years; and the male:female patient distribution is roughly 2:1.
Characteristically, computerized tomography (CT) scans of lymphomas show a mass which is often large with regular contours, moderate mass effect, and hyper- or isodensity with marked and often homogeneous enhancement. In the series of 30 patients reported, the locations of lesions, in order of decreasing frequency, were the frontocallosal and temporal regions, the basal ganglia, and the cerebellum. Multiple lesions were present in 15% of these cases (20% to 40% in the literature). The following features should raise the suspicion of intracranial lymphoma: mirror lesions of the basal ganglia, bilateral subependymal infiltration, and leptomeningeal involvement contiguous with an intracerebral mass.
According to the literature, the angiographic finding typical of lymphoma is an avascular tumor. A blush or vascular encasement of the mass seems to be rare, and the present series was in accordance with other reports in this respect. Differential diagnostic consideration should include meningioma, glioblastoma, metastatic disease, and focal infectious lesions such as toxoplasmosis or multifocal progressive leukoencephalitis, particularly in immunodepressed subjects. Diagnosing lymphoma from CT scans offers the alternative of substituting stereotaxic biopsy and neuropathological diagnosis for the more aggressive open surgical approach, since radiation therapy and possibly chemotherapy usually prove to be the treatment of choice.
Effect of dexamethasone, indomethacin, ibuprofen, and probenecid on carrageenan-induced brain inflammation
Authors: Gamache Daniel A. , Ellis Earl F. 
Published: May 2009

✓ A model of brain inflammation has recently been developed in mice using intraventricular injection of carrageenan (CAR). This model is characterized by increased brain water and vascular permeability, by neutrophil extravasation, and by evidence of increased pro-inflammatory arachidonic acid metabolites. The purpose of the current experiments was to determine the mechanism(s) by which CAR induces brain inflammation and to determine the utility of the CAR model in testing systemically administered therapeutic agents for their capacity to inhibit brain inflammation. Dexamethasone inhibited the increased brain water but not the increased vascular permeability produced by CAR. Indomethacin, an inhibitor of prostaglandin formation, suppressed peripheral inflammation produced by local injection of CAR but not brain inflammation produced by intraventricular CAR injection. Subsequent studies with carbon-14-labeled indomethacin showed that indomethacin penetrates peripheral tissues but is excluded from normal brain or brains inflamed by injection of CAR. Ibuprofen, another prostaglandin synthesis inhibitor, also had no effect on brain inflammation. Probenecid, an organic acid transport inhibitor, completely inhibited CAR-induced brain inflammation and also slowed brain elimination of intraventricularly administered prostaglandins.
These experiments suggest, but do not conclusively prove, that increased prostaglandin formation contributes to brain inflammation. Also, the results with indomethacin and CAR-induced brain inflammation indicate that CAR-induced inflammation may be a useful model for screening for the ability of anti-inflammatory agents to cross the blood-brain barrier and exert their effect on brain inflammation.
The minor leak preceding subarachnoid hemorrhage
Authors: Leblanc Richard 
Published: May 2009

✓ Thirty-four of 87 consecutive patients with subarachnoid hemorrhage from a cerebral aneurysm had a premonitory minor leak. There were 12 men and 22 women, aged 25 to 73 years (mean 44.4 years). Twenty-two had a small and 12 had a large aneurysm located on the internal carotid artery (17 cases), anterior communicating artery (10 cases), middle cerebral artery (five cases), and pericallosal artery (two cases). Fifty-two percent of patients with a minor leak from an internal carotid artery aneurysm had ipsilateral, hemicranial, hemifacial, or periorbital pain. Half of the patients initially saw a physician, but in no case was the correct diagnosis made. Twenty-five patients had a major rupture within 24 hours to 4 weeks after findings suggesting a minor leak, with a mortality rate of 53%. Nine other patients were diagnosed by lumbar puncture or computerized tomography (CT) scanning after initial misdiagnosis and were operated on, without mortality, before a major rupture could occur. The CT scans were negative in 55% of patients with a minor leak, but lumbar puncture, when performed, was always positive.
A minor leak prior to major aneurysmal rupture is a common occurrence and, if unrecognized, is associated with a high mortality. Computerized tomography scanning is unreliable in diagnosing this event, and lumbar puncture is the examination of choice once intracranial hypertension has been ruled out.
Deterioration following spinal cord injury
Authors: Marshall Lawrence F. , Knowlton Sharen , Garfin Steven R. , Klauber Melville R. , Eisenberg Howard M. , Kopaniky Dennis , Miner Michael E. , Tabbador Kamran , Clifton Guy L. 
Published: May 2009

✓ The results are presented of a prospective study of the course of 283 spinal cord-injured patients who were consecutively admitted to five trauma centers participating in the Comprehensive Central Nervous System Injury Centers' program of the National Institutes of Health. Of the 283 patients, 14 deteriorated neurologically during acute hospital management. In 12 of the 14, the decline in neurological function could be associated with a specific management event, and in nine of these 12 the injury involved the cervical cord. Nine of the 14 patients who deteriorated had cervical injuries, three had thoracic cord injuries, and two had thoracolumbar junction injuries. Management intervention was identified as the cause of deterioration in four of 134 patients undergoing operative intervention, in three of 60 with skeletal traction application, in two of 68 with halo vest application, in two of 56 undergoing Stryker frame rotation, and in one of 57 undergoing rotobed rotation. Early surgery on the cervical spine when cord injury is present appears hazardous, since each of the three patients with a cervical cord injury who deteriorated was operated on within the first 5 days. No such deterioration was observed following surgery performed from the 6th day on. In two other patients, deterioration did not appear to be related to management but was a direct product of the underlying disease or of systemic complications.
Deterioration following hospitalization for spinal cord injury is relatively uncommon — 4.9% in this large series. In most instances, decline in function could be attributed to specific management procedures. These changes must not be interpreted as representing failure to provide optimal care but rather should be seen as the inevitable product of an attempt to manage patients with spinal cord and column injuries, many of which are clearly unstable.
Hemodynamic and metabolic effects of cerebral revascularization
Authors: Leblanc Richard , Tyler Jane L. , Mohr Gérard , Meyer Ernst , Diksic Mirko , Yamamoto Lucas , Taylor Laughlin , Gauthier Serge , Hakim Antoine 
Published: May 2009

✓ Pre- and postoperative positron emission tomography (PET) was performed in six patients undergoing extracranial to intracranial bypass procedures for the treatment of symptomatic extracranial carotid occlusion. The six patients were all men, aged 52 to 68 years. Their symptoms included transient ischemic attacks (five cases), amaurosis fugax (two cases), and completed stroke with good recovery (one case). Positron emission tomography was performed within 4 weeks prior to surgery and between 3 to 6 months postoperatively, using oxygen-15-labeled CO, O2, and CO2 and fluorine-18-labeled fluorodeoxyglucose. Cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rates for oxygen and glucose (CMRO2 and CMRGlu), and the oxygen extraction fraction (OEF) were measured in both hemispheres. Preoperatively, compared to five elderly control subjects, patients had increased CBV, a decreased CBF/CBV ratio, and decreased CMRO2, indicating reduced cerebral perfusion pressure and depressed oxygen metabolism. The CBF was decreased in only one patient who had bilateral carotid occlusions; the OEF, CMRGlu, and CMRO2/CMRGlu and CMRGlu/CBF ratios were not significantly different from control measurements.
All bypasses were patent and all patients were asymptomatic following surgery. Postoperative PET revealed decreased CBV and an increased CBF/CBV ratio, indicating improved hemodynamic function. This was associated with increased CMRO2 in two patients in whom the postoperative OEF was also increased. The CMRGlu and CMRGlu/CBF ratio were increased in five patients. Changes in CBF and the CMRO2/CMRGlu ratio were variable. One patient with preoperative progressive mental deterioration, documented by serial neuropsychological testing and decreasing CBF and CMRO2, had improved postoperative CBF, CBV, and CMRO2 concomitant with improved neuropsychological functioning and oxygen hypometabolism. It is concluded that symptomatic carotid occlusion is associated with altered hemodynamic function. Cerebral revascularization results in decreased CBV, indicating improved hemodynamic reserve, but does not consistently improve oxygen metabolism.
Monitoring facial EMG responses during microvascular decompression operations for hemifacial spasm
Authors: Møller Aage R. , Jannetta Peter J. 
Published: May 2009

✓ Facial electromyographic (EMG) responses were monitored intraoperatively in 67 patients with hemifacial spasm who were operated on consecutively by microvascular decompression of the facial nerve near its exit from the brain stem. At the beginning of the operation, electrical stimulation of the temporal or the zygomatic branch of the facial nerve gave rise to a burst of EMG activity (autoexcitation) and spontaneous EMG activity (spasm) that could be recorded from the mentalis muscle in all patients. In some patients, the spontaneous activity and the autoexcitation disappeared after the dura was incised or when the arachnoid was opened, but stimulation of the temporal branch of the facial nerve caused electrically recordable activity in the mentalis muscle (lateral spread) with a latency of about 10 msec that lasted until the facial nerve was decompressed in all but one patient, in whom it disappeared when the arachnoidal membrane was opened.
When the facial nerve was decompressed, this lateral spread of antidromic activity disappeared totally in 44 cases, in 16 it was much reduced, and in seven it was present at the end of the operation at about the same strength as before craniectomy. In four of these last seven patients there was still very little improvement of the spasm 2 to 6 months after the operation; these four patients underwent reoperation. In two of the remaining three patients, the spasm was absent at the 3- and 7-month follow-up examination, respectively, and one had mild spasm. Of the 16 patients in whom the lateral spread response was decreased as a result of the decompression but was still present at the end of the operation, 14 had no spasm and two underwent reoperation and had mild spasm at the last examination. Of the 44 patients in whom the lateral spread response disappeared totally, 42 were free from spasm and two had occasional mild spasm at 6 and 13 months, respectively, after the operation.
Monitoring of facial EMG responses is now used routinely by the authors during operations to relieve hemifacial spasm, and is performed simultaneously with monitoring of auditory function for the purpose of preserving hearing. The usefulness of monitoring both brain-stem auditory evoked potentials recorded from electrodes placed on the scalp and compound action potentials recorded directly from the eighth cranial nerve is evaluated.
“Extrapolated” creatine kinase-BB isoenzyme activity in assessment of initial brain damage after severe head injury
Authors: Hans Pol , Born Jacques Daniel , Albert Adelin 
Published: May 2009

✓ The severity of initial brain damage is an important risk factor in determining the prognosis of head trauma. It can be assessed by assigning neurological scores or by determining the cerebrospinal fluid (CSF) activity of the isoenzyme creatine kinase-BB (CK-BB). In 10 severely head-injured patients serial CSF samples were obtained during the first 24 hours after trauma, and exponential decay of CK-BB activity with an average half-life of 4.5 hours was demonstrated. This finding led the authors to propose an “extrapolated” CK-BB activity, which theoretically occurs immediately after injury and is calculated from a single CK-BB recording, as a new index for assessing the degree of initial brain damage.
In 50 patients with severe head injury, the prognostic ability of “observed” and “extrapolated” CK-BB activity was compared with two clinical scoring systems that evaluate severity of head trauma (the Glasgow and the Glasgow-Liège Coma Scales). “Extrapolated” CK-BB activity proved to be the best prognostic factor. With a CK-BB cutoff point of 330 U/liter, a true-positive rate of 79% and a true-negative rate of 73% were obtained. These results suggest the usefulness of measuring CK-BB activity in CSF as soon as possible after hospital admission for head injury.
Oculomotor nerve regeneration in rats
Authors: Fernandez Eduardo , Gangitano Carlo , Del Fà Aurora , Sangiacomo Corrado Olivieri , Talamonti Giuseppe , Draicchio Francesco , Sbriccoli Alessandro 
Published: May 2009

✓ To study oculomotor nerve regeneration in rats, the oculomotor nerve was approached microsurgically and was sectioned at the base of the skull. The nerve stumps were reapproximated and affixed with a plasma clot in Group I animals and were separated by a gap in Group II animals. Visceral eye motility was evaluated weekly between 1 day and 40 weeks after surgery by recording the pupillary diameter under standardized photic stimulation. Somatic eye motility was assessed after 26 weeks by measuring the ocular displacement evoked by vestibular stimulation in the horizontal and vertical planes. Nerve regeneration was documented histologically and morphometrically at 8, 16, and 40 weeks after section. The selectivity of axonal regeneration to the extraocular muscles was investigated after 26 weeks by mapping (with injection of retrograde horseradish peroxidase) the motoneurons that supplied each reinnervated muscle.
Between 6 and 20 weeks after section, the pupil diameter showed a progressive reduction in Group I rats, and no changes were observed in Group II rats. Compared with normal rats, the amplitude of horizontal and vertical ocular displacements was decreased, respectively, by 30% and 45% in Group I and by 65% and 80% in Group II. In Group I rats, the vestibular stimulation in the horizontal plane evoked anomalous eye movements with vertical components. On histological examination, regenerated nerves showed a progressive increase of axonal diameter and myelin-sheath thickness. Reinnervated muscles were associated with a less specific, bilateral representation in the midbrain compared with normal muscles, which have unilateral representation. The changes of the somatotopic organization were interpreted as being the result of the misdirected regrowth of axons in the postlesional nerve stump and of the collateral sprouting in the midbrain.