bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of physiological responses to percussive brain trauma in dogs and sheep
Authors: Millen J. Eugene , Glauser Frederick L. , Fairman R. Paul
Published: May 2009

✓ Physiological variables were monitored in dogs and sheep after exposure of the brain to a pressure wave produced by a fluid-percussion device. Mean systemic arterial pressure (SAP), mean pulmonary arterial pressure (PAP), and pulmonary wedge pressure (PWP) were recorded prior to and following trauma. Lung lymph flows (QLYM) were measured prior to and for 2 hours after trauma. Plasma catecholamine levels were quantitated prior to and at 30 seconds following trauma. In 16 dogs, SAP increased from 123 ± 14.6 to 254 ± 60.8 mm Hg (p < 0.0001), PAP increased from 17 ± 4.4 to 27 ± 10.8 mm Hg (p < 0.05), and PWP increased from 4 ± 2.4 to 15 ± 8.8 mm Hg (p < 0.0001), all at 30 seconds posttrauma. All pressures returned to near baseline values within 6 minutes. The QLYM from the right lymph duct in 12 dogs increased from 0.82 ± 0.77 to 2.7 ± 2.1 and 1.88 ± 1.82 ml/30 min, respectively, at 30 and 120 minutes. In five dogs the plasma concentrations of dopamine, epinephrine, and norepinephrine increased from 234 ± 98 to 1906 ± 1384, 609 ± 641 to 19,813 ± 10,234, and 388 ± 194 to 3223 ± 992 pg/ml, respectively (all p < 0.01). In sheep there were no changes in SAP, PAP, PWP, QLYM, or catecholamine levels in response to percussive wave trauma up to 10 atm. Ratios of lung tissue water to dry weight were not significantly different from control animals in either species. The authors conclude that in dogs there is a profound sympathetic discharge resulting in dramatic elevations in plasma catecholamines, systemic and pulmonary artery hypertension, and an increase in pulmonary lymph flow. Sheep fail to demonstrate changes in any of these variables after severe percussive wave brain trauma.
Revascularization of the anterior cerebral artery
Authors: Ikeda Akira , Okada Tomohisa , Shibuya Masato , Noda Satoshi , Sugiura Masakazu , Iguchi Ikuzo , Gonda Takami , Kageyama Naoki
Published: May 2009

✓ Intracranial anastomosis between the distal anterior cerebral arteries (ACA's) was performed on two patients. One patient had isolated occlusion of the proximal ACA on one side causing monoparesis in the leg, and the other patient suffered from occlusion of the internal carotid artery and a small anterior communicating artery. The weakness of the legs improved immediately after surgery and cerebral angiography revealed a good filling of the bilateral ACA's. Technical aspects and indications for the procedure are discussed.
Cranioplasty with inner table of bone flap
Authors: Kyoshima Kazuhiko , Gibo Hirohiko , Kobayashi Shigeaki , Sugita Kenichiro
Published: May 2009

✓ A new method of cranioplasty is described in which the inner table of the bone flap obtained during craniotomy is used for grafting. The method was used in 10 cases to repair bone defects caused by a growing skull fracture in two, created during removal of an invasive skull tumor in two, during the approach to intraorbital tumors in two, and secondary to craniectomy for additional exposure in four. The method has the advantage that a piece of the inner table for grafting can be obtained from the craniotomy bone flap, without the need for an additional skin incision or taking a graft from another part of the body, and foreign-body reaction is minimal.
Clip with enclosed spring for aneurysm surgery
Authors: Rhoton Albert L. , Merz William
Published: May 2009

✓ A clip for aneurysm surgery has been designed with several unique features. The coil spring is fully hidden and protected within two hub sections so that it cannot be handled or become entrapped in tissue. The clip is milled from a piece of solid stock of nonmagnetic stainless steel to the desired size and shape by a computer milling process, thus avoiding the stresses and structural weaknesses caused by the bending, curling, and milling needed to prepare clips made from wire or sheet metal. The only means of opening the clip is by applying pressure to the solid milled surfaces, thus the spring cannot be weakened or bent by squeezing it or by trauma applied to the clip. The clip may be grasped in either a clip applier that holds the clip in one fixed position or in an applier that allows the clip to be rotated through an arc of 180°.
Results of trimethoprim-sulfamethoxazole prophylaxis in ventriculostomy and shunting procedures
Authors: Blomstedt Göran C.
Published: May 2009

✓ The author reports the results of a study to assess the effectiveness of a trimethoprim-sulfamethoxazole combination as prophylaxis in ventriculostomy or shunting operations. Between 1980 and 1983, 122 patients undergoing shunting procedures were randomly assigned to receive trimethoprim-sulfamethoxazole (Group 1, 62 cases) or a placebo (Group 2, 60 cases). The same regimen was followed at each operation, and the patients were followed for a minimum of 6 months. There was a higher infection rate in the placebo group (14 of 60 patients compared with 4 of 62 patients in the antibiotic group, p < 0.01). The antibiotic protected against early infections (nine of the 60 patients in Group 2 against none of the patients in Group 1), but not against late infections (four of the 62 in Group 1 compared with five of the 60 in Group 2). During the same period, 52 patients undergoing ventriculostomy only were also randomly assigned to receive trimethoprim-sulfamethoxazole (Group 3) or placebo (Group 4). There were no differences in the infection rates between these groups (one of 25 in Group 3 as against one of 27 in Group 4).
The role of calcium and cellular membrane dysfunction in experimental trauma and subarachnoid hemorrhage
Authors: Hubschmann Otakar R. , Nathanson Douglas C.
Published: May 2009

✓ Acute subarachnoid hemorrhage (SAH) and intraparenchymal hematoma (IPH) in cats are accompanied by massive cellular depolarization. This depolarization, characterized by potassium (K+) efflux and calcium (Ca++) influx, results in membrane destabilization, osmotic imbalance, and a decrease in electrical conduction. The Ca++ influx appears to initiate a chain reaction that, in some instances, may result in delayed cell destruction. The ionic dysequilibrium probably contributes to both brain engorgement and spasm in large vessels. The cellular depolarization and calcium-induced cell membrane injury at the moment of impact may play a greater role in the pathophysiology of head trauma than previously thought.
Freeze-fracture replica study of capillary endothelium after embolization in the dog
Authors: Inoue Masaru , Fukushima Masaaki , Tsutsumi Kenji , Shibata Shobu , Mori Kazuo , Setoguchi Takao
Published: May 2009

✓ The underlying mechanisms that lead to brain edema following ischemic insult have been subject to much debate. In this study, experimental cerebral infarction was produced in 25 dogs by injecting 1 or 2 silicone rubber cylinders through the cervical internal carotid artery. The animals were sacrificed 24 hours after embolization. Freeze-fracture studies were conducted on the plasma membrane of the capillary endothelium from 15 control and 25 ischemic dogs. No definite findings of tight junction opening were made in the ischemic preparations. Pinocytotic vesicles were seen as concave areas on the protoplasmic face (PF) of the plasma membrane and as protrusions on the extracellular face (EF). The average pinocytotic vesicle count per square micron was increased in ischemic animals. On the luminal side, it reached 22.0 ± 1.2/sq µ in the 50 PF samples and 29.5 ± 1.3/sq µ in the 50 EF samples in the experimental preparations, as compared to 7.2 ± 0.5 sq µ in the 50 PF samples and 9.0 ± 0.6 sq µ in the 50 EF samples in normal cortex. The average area of the vesicles was also enlarged in experimental animals: 4990.7 ± 798 sq nm in the 50 PF samples and 4762.8 ± 878 sq nm in the 50 EF samples, as compared to 3567.7 ± 570 sq nm in the 50 PF samples and 3404.5 ± 573 sq nm in the 50 EF samples in normal cortex (p > 0.01). These results indicate that transcellular transportation by pinocytotic vesicles plays an important role in the increase of capillary permeability observed in an ischemic model.
Role of monoamines in experimental spinal cord injury in rats
Authors: Kurihara Masaki
Published: May 2009

✓ A spinal cord injury was produced in Wistar rats by extradural compression of the cord with a Sugita aneurysm clip for 5 seconds. During a 2-week observation period following the injury, the tissue norepinephrine (NE), dopamine (DA), and serotonin (5-HT) concentrations decreased uniformly at and below the injured site. The chemical denervation of NE or 5-HT neurons produced by the intraspinal injection of 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine (5,7-DHT) 2 weeks before the injury did not cause a marked difference in the extent of hemorrhagic necrosis of the spinal cord after trauma as compared to control animals without pretreatment. In the rats pretreated with 6-OHDA, NE was decreased to less than 30% of control (non-pretreated) values, and, beginning at 5 days after injury, motor performance (assessed quantitatively with the inclined-plane method) was significantly improved compared to results in the non-pretreated control rats. The rats pretreated with 5,7-DHT showed no change from control animals. Spinal cord samples from non-pretreated control animals obtained at the injury site 30 minutes after the compression injury showed a marked decrease in the activity of synaptosomal Na+-K+-ATPase (adenosine triphosphatase) of about 50%, and an increase in both thiobarbituric acid reaction substance (about 170%) and cyclic guanine monophosphate (about 150%). The NE-denervated rats showed no significant changes in these three parameters.

The results indicated that NE released after crush injury may impair the neuronal cell membrane around the lesion site by induction of lipid peroxidation. The possible mechanisms by which released NE may alter membrane function are discussed.
Modulation of meningioma cell growth by sex steroid hormones in vitro
Authors: Jay Jeffrey R. , MacLaughlin David T. , Riley Kathleen R. , Martuza Robert L.
Published: May 2009

✓ Meningiomas were removed from four patients and estradiol binding was measured in the tumor tissue. Cell cultures were established and an in vitro system was developed to test the biological activity of physiologically relevant concentrations (10−7 M and 10−9 M) of estradiol-17pβ, progesterone, and the antiestrogen, tamoxifen, on the growth of meningioma cells in early culture (passages 3 to 5). Assays of the frozen surgical specimens demonstrated cytosolic estradiol binding, with levels of 0.3 to 26.7 femtomoles (fM)/mg protein, in all four tumors. Nuclear estradiol binding was detected in three tumors, with levels of 16.8 to 39.5 fM/mg protein. In cell culture, estradiol at either 10−7 M or 10−9 M consistently stimulated cell growth in all four cultures. When tested alone, progesterone stimulated the growth of all four tumors and tamoxifen stimulated the growth of three of the four tumors, but the levels of stimulation produced by either of these compounds were less pronounced than the level produced by estradiol. When tested in combination with estradiol, progesterone significantly inhibited the growth stimulation produced by estradiol in all four meningioma cultures and tamoxifen significantly inhibited estradiol-induced growth stimulation in three of four cultures. It is not known if these effects are mediated by a hormone receptor or by a hormone binder different from a true receptor, or if they are caused by alterations in cellular metabolism that are independent of specific hormone binding. However, the authors conclude that this in vitro technique can be used to further study the biological activity of hormones on human meningiomas in order to answer these questions.
Acromegaly associated with suprasellar and pulmonary hemangiopericytomas
Authors: Yokota Masayuki , Tani Eiichi , Maeda Yukio , Morimura Tatsuo , Kakudo Kennichi , Uematsu Kunio
Published: May 2009

✓ The authors report the case of a 35-year-old acromegalic woman who developed amenorrhea and decreased left vision, and who was found to have suprasellar and pulmonary hemangiopericytomas. Total removal of the suprasellar hemangiopericytoma resulted in normalization of the plasma human growth hormone (GH) level and a marked decrease in size of the pulmonary hemangiopericytoma. Immunoperoxidase studies for GH and human hypothalamic growth hormone-releasing factor (GHRF) demonstrated immunoreactive intracellular GH only in the suprasellar hemangiopericytoma, with no immunoreactive intracellular GHRF evident in either the suprasellar or pulmonary hemangiopericytoma.
Intraventricular hemorrhage due to aneurysms of the distal posterior inferior cerebellar artery
Authors: Yeh Hwa-Shain , Tomsick Thomas A. , Tew John M.
Published: May 2009

✓ Three cases of ruptured aneurysm of the distal posterior inferior cerebellar artery (PICA) presenting with isolated intraventricular hematoma are reported. All of the aneurysms originated from the lateral medullary segment of the PICA and ruptured into the lateral recess of the fourth ventricle. The diagnosis of distal PICA aneurysm should be considered if isolated intraventricular hematoma is found without obvious parenchymal hemorrhage or subarachnoid blood in the basal cisterns. Complete vertebral arteriography is a requisite for the recognition of this condition. The outcome in patients with these aneurysms should be good if surgical repair is performed before rebleeding occurs.
Extracranial-intracranial arterial bypass for middle cerebral artery stenosis and occlusion
Authors: Andrews Brian T. , Chater Norman L. , Weinstein Philip R.
Published: May 2009

✓ Forty-seven patients with middle cerebral artery (MCA) stenosis and 18 patients with MCA occlusion underwent extracranial-intracranial arterial bypass procedures. Patients presented with a history of transient ischemic attacks (TIA's), reversible ischemic neurological deficits, TIA's after initial stroke, stroke-in-evolution, or completed stroke. Angiography revealed that the MCA stenosis ranged from 70% to over 95%. Two patients (4.3%) in the stenosis group had a perioperative stroke (within 30 days of operation). There was no perioperative mortality. In the occlusion group, no patient had a perioperative stroke, and one patient (5.5%) died from a non-neurological disease. The TIA's resolved completely in 90% of the patients with stenosis and in 91.6% of those with occlusion. No patient with MCA stenosis had a late ipsilateral stroke, although five had a contralateral or vertebrobasilar stroke. One patient with MCA occlusion had a late ipsilateral stroke. The bypass patency rate at late follow-up review was 100%.

The results of intracranial-extracranial arterial bypass procedures appear to be similar for patients with either stenosis or occlusion of the MCA. Symptomatic relief of TIA's was excellent and, in two patients with progressive stroke-in-evolution, the deficit was stabilized. The incidence of postoperative ipsilateral stroke was low in patients with TIA's alone or with TIA's after an initial stroke, but among patients with completed stroke, improvement was confined to slight reduction in the neurological deficit.
Intravenous fluid loading as prophylaxis for paradoxical air embolism
Authors: Colohan Austin R. T. , Perkins Nancy A. K. , Bedford Robert F. , Jane John A.
Published: May 2009

✓ Paradoxical cerebral air embolism has been described in neurosurgical operations performed on patients in the seated position. This problem is thought to result most often from a probe-patent foramen ovale. It has been postulated that right atrial pressure exceeds left atrial pressure when paradoxical air embolism occurs. A study is described in which intravenous fluid loading is compared with routine fluid management in 20 patients undergoing neurosurgical operations in the seated position. In order to investigate if intravenous fluid loading would decrease the risk of paradoxical air embolism during neurosurgical operations on seated patients, 20 patients were assigned randomly to two groups: 10 patients received normal intravenous fluid replacement (1220 ± 102 ml), and 10 received augmented fluid replacement (2800 ± 400 ml). Right atrial and pulmonary capillary pressures were monitored for evidence of an interatrial pressure gradient that would force air emboli from the right atrium into the left atrium via a probe-patent foramen ovale. Four of 10 patients receiving routine fluid administration developed right atrial pressure greater than pulmonary capillary wedge pressure (and hence, indirectly, greater than left atrial pressure), whereas none of the 10 patients with augmented fluid loading developed this condition (p = 0.04). The authors conclude that augmented intravenous fluid loading may be effective in preventing systemic air embolism during neurosurgical operations performed on patients in the seated position.
Epidemiological findings in a brain-tumor cluster in Western Missouri
Authors: Morantz Robert A. , Neuberger John S. , Baker Larry H. , Beringer Gary B. , Kaufman Andrew B. , Chin Tom D. Y.
Published: May 2009

✓ A cluster of seven primary brain neoplasms was identified in a town of 3000 population during the 10-year period from 1973 to 1982. With six deaths, this represents an age-adjusted mortality rate 4.1 times greater than expected. No other neoplasms were found to be in excess of the anticipated incidence in this town. When brain-tumor mortality rates in 36 other towns of approximately the same population were calculated, only one other town was found to have an excessive rate. All seven tumors in this study were histologically verified: six were diagnosed as glioblastoma multiforme. Interviews were conducted with patients or next-of-kin to obtain the exposure histories of the patients. A number of respondents reported occupational or residential exposure either to a shoe factory or to one of the several chicken hatcheries in the town. Many of the patients ate fish from local ponds that had previously been used as coal mining strip pits. Two patients were siblings. None of the patients had a history of significant head trauma. This unique situation may provide an opportunity to learn more about environmental risk factors for brain neoplasia. Further epidemiological studies are planned.
Traumatic extradural hematomas in infancy and childhood
Authors: Dhellemmes Patrick , Lejeune Jean-Paul , Christiaens Jean-Louis , Combelles Guy
Published: May 2009

✓ The authors report a series of 144 children with traumatic extradural hematomas operated on at the Lille Department of Neurosurgery between 1969 and 1982. The patients are divided into different groups according to age, and clinical findings were recorded for each age group. The overall mortality rate was 9%. The authors demonstrate that prognosis is related to age, neurological status at time of surgery, and duration of postoperative coma.
Indomethacin-mediated improvement following middle cerebral artery occlusion in cats
Authors: Dempsey Robert J. , Roy Mark W. , Meyer Kathleen L. , Donaldson David L.
Published: May 2009

✓ Focal cerebral ischemia initiates multiple detrimental effects in the brain. Chief among these are the regional development of ischemic edema, decreased local perfusion, altered neuronal function, and eventual infarction. To determine if pretreatment with the cyclo-oxygenase inhibitor, indomethacin, would result in improvement in these parameters, adult cats were given indomethacin or control solvent (4 mg/kg intraperitoneally twice daily) and were studied for periods up to 24 hours after right middle cerebral artery occlusion. The interaction of anesthetic agents with indomethacin was also examined in separate groups of experimental animals using pentobarbital and ketamine. In cats allowed to recover from pentobarbital anesthesia, indomethacin reduced gray and white matter edema at 6 and 24 hours after occlusion (p < 0.05). This was noted in densely ischemic areas (indomethacin = 84.3%, control = 87.5%), in “penumbra” regions (indomethacin = 82.5%, control = 85.3%), and in nonischemic zones (indomethacin = 81.5%, control = 82.3%) at 24 hours. Somatosensory evoked potential amplitude and central latency were also improved in the indomethacin group (p < 0.05), as was cerebral perfusion (p < 0.05). In animals anesthetized with continuous ketamine administration, cerebral edema and perfusion as well as evoked potentials were not significantly improved in any region by indomethacin. Regional cerebral blood flow in the group was increased by indomethacin in the nonischemic opposite hemisphere (indomethacin = 64.7 cc/100 gm/min, control = 48.5 cc/100 gm/min, p < 0.05), but not in the penumbra region of the ischemic hemisphere (indomethacin = 15.0 cc/100 gm/min, control = 18.6 cc/100 gm/min, p < 0.05), when measured 4 hours after occlusion. This suggested a steal phenomenon.

Beneficial effects of indomethacin were evident in the presence of pentobarbital, but not after ketamine anesthesia. This suggests a synergism dependent on decreased arachidonic acid production from pentobarbitalstabilized membranes coupled with diminished production of cyclic endoperoxides from available arachidonate due to inhibition of cyclo-oxygenase with indomethacin.
Micro vascular alterations following cerebral contusion in rats
Authors: Hekmatpanah Javad , Hekmatpanah Cameron R.
Published: May 2009

✓ Cerebral contusion was caused in 18 rats by dropping various weights on an exposed dura of one hemisphere. One or 3 hours after the injury the animals were sacrificed by perfusion with paraformaldehyde-glutaraldehyde solution. The traumatic micro vascular and neural tissue alterations were studied with light, scanning, and electron microscopic techniques. The microvascular obstructions and damage were revealed in this study as major histological alterations, causing secondary neural damage. The obstruction of the vessels appeared to have been caused 1) by extra vascular pressure from destroyed and swollen tissue, petechial hemorrhage, and dissecting extraluminal clots; and 2) by intravascular clots. Besides the tearing and shearing effects causing petechial hemorrhages, the capillary walls were often thinned and irregular.
Detection and measurement of steady-state evoked potentials in real-time using a lock-in amplifier
Authors: Schacham Shmuel E. , Pratt Hillel
Published: May 2009

✓ A system for recording evoked potentials, in which a lock-in amplifier replaces the averaging computer, is described. With this system, the set-up is much the same as in the conventional apparatus, with the following exceptions: 1) the amplifier gain is set at only a few thousands; 2) analogue-to-digital conversion and computer averaging is replaced by a lock-in amplifier; and 3) the output of the system is an analogue signal representing the amplitude of the recorded steady-state evoked potentials and the phase of baseline crossings. This set-up is much less costly than the conventional apparatus, much easier to operate, and, with its real-time output, may provide an ideal technique for screening and monitoring purposes.
Applications of monoclonal antibodies in the diagnosis and treatment of primary brain tumors
Authors: Bullard Dennis E. , Bigner Darell D.
Published: May 2009

✓ The development of monoclonal antibodies has resulted in marked expansion in understanding the central nervous system (CNS). This has been especially true in the study of human neuroectodermal tumors where monoclonal antibodies have been used as physiological probes to define and characterize human neuroectodermal tumor-associated antigens. Utilizing monoclonal antibodies, neuroectodermal tumor-associated antigens have been described in four broad categories; biochemically defined markers, shared nervous systemlymphoid cell markers, shared neuroectodermal-oncofetal markers, and putative restricted tumor markers. Preliminary data have demonstrated the ability to localize animal and human tumors in vitro, ex vivo, and in vivo. Early application of monoclonal antibody technology to neuroimmunology and neuro-oncology has resulted in a new awareness of the complex relationships that exist within the CNS. Their specificity and reproducibility may provide the means to qualitatively and quantitatively define the phenotypic heterogeneity of human neuroectodermal tumors. Potentially, monoclonal antibodies, alone or as carriers of radionuclides, drugs, or toxins, may allow successful diagnosis and treatment of human neuroectodermal tumors.
Cerebral revascularization to a main limb of the middle cerebral artery in the Sylvian fissure
Authors: Diaz Fernando G. , Umansky Felix , Mehta Bharat , Montoya Salvador , Dujovny Manuel , Ausman James I. , Cabezudo Jose
Published: May 2009

✓ Thirteen patients underwent an anastomosis of the superficial temporal artery (STA) or a saphenous vein graft to one of the secondary trunks of the middle cerebral artery (MCA). They included five patients with giant MCA trifurcation aneurysms, four patients in whom an earlier conventional STA-MCA anastomosis had become occluded, two patients who had stenosis of one of the secondary limbs of the MCA, and one patient who had a carotid-cavernous fistula. One patient had a saphenous vein graft from the common carotid artery to a secondary trunk of the MCA to bypass an occluded internal carotid artery and severely stenosed external carotid artery. The primary advantages of this procedure are that a large-caliber anastomosis to one of the secondary limbs of the MCA immediately restores flow into the MCA tree with a larger amount of vessel filling than with a standard cortical bypass, and large vessels can be used for the anastomosis. The disadvantages are that one of the secondary branches of the MCA must be occluded, the cerebral hemisphere around the Sylvian fissure must be retracted, a lumbar subarachnoid drain is needed, and the anastomosis must be performed deep within the Sylvian fissure.

The procedure is a satisfactory alternative in cases in which a conventional STA-MCA anastomosis has either failed or would be less likely to succeed.
Delayed onset of traumatic extradural hematoma
Authors: Borovich Bernardo , Braun Jacob , Guilburd Joseph N. , Zaaroor Menashe , Michich Michel , Levy Lion , Lemberger Anshel , Grushkiewicz Ian , Feinsod Moshe , Schächter Izu
Published: May 2009

✓ During a 4½-year period, seven patients with delayed onset of an extradural hematoma were seen among 80 consecutively treated cases of extradural hematoma for a frequency of 8.75%. The hematomas were insignificant or not present on initial computerized tomography (CT) scanning. Repeat CT scans within 24 hours of admission showed sizeable hemorrhages. Six hematomas were evacuated, and one was reabsorbed spontaneously. In only one patient did neurological deterioration herald the onset of the extradural hematoma, four patients remained unchanged, and two improved before diagnosis. Intracranial pressure (ICP) was monitored in five patients, four of whom showed intermittent rise in pressure despite preventive treatment. Intracranial hypotension and rapid recovery from peripheral vascular collapse seemed to be contributory factors in the delayed onset of an extradural hematoma. Awareness of this entity, a high degree of vigilance, ICP monitoring, and repeat CT scanning within 24 hours of injury are strongly recommended in these cases, especially after decompression by either surgical or medical means, recovery from shock, or whenever there is evidence of even minimal bleeding under a skull fracture on the initial CT scan.
Effect of the skull and dura on neural axis pressure-volume relationships and CSF hydrodynamics
Authors: Shapiro Kenneth , Fried Arno , Takei Futoshi , Kohn Ira
Published: May 2009

✓ The pressure-volume index (PVI) technique of bolus manipulation of cerebrospinal fluid (CSF) was used to measure changes of neural axis volume buffering-capacity and CSF dynamics produced by different conditions of the skull and dura. Twenty-eight cats were studied in the intact state, after bilateral craniectomy, and with the dura opened. At each stage of altering the container of the brain, the following parameters were obtained: steady-state intracranial pressure (ICP), sagittal sinus venous pressure, PVI, and the resistance to the absorption of CSF. The resistance to absorption of CSF was determined using both the bolus injection and the continuous infusion of fluid.

After craniectomy, PVI increased from 0.76 ± 0.04 to 1.3 ± 0.07 ml (± standard error of the mean) (p < 0.001) and increased further to 3.6 ± 0.17 ml (p < 0.001) after opening the dura. The resistance to absorption of CSF (Ro), determined by bolus injection, decreased after craniectomy from 91.3 ± 7.5 to 56.3 ± 6.2 mm Hg/ml/min (p < 0.001) and decreased further to 8.9 ± 0.66 mm Hg/ml/min (p < 0.001) after opening the dura. Although resistance determined by constant infusion was similar, results were dependent on the rate of infusion. Despite these changes of resistance and PVI, steady-state ICP and sagittal sinus venous pressure were similar in all three conditions of the skull and dura. These studies indicate that changes of the container of the brain affect pressure-volume relationships within the neural axis. However, the changes of resistance to absorption of CSF are in a direction that preserves a steady-state hydrodynamic equilibrium.
Acute changes in regional cerebral metabolite values following experimental blunt head trauma
Authors: Wagner Kenneth R. , Tornheim Patricia A. , Eichhold Mary K.
Published: May 2009

✓ A Remington humane stunner was used to deliver a blow to the left side of the surgically-exposed skull in ketamine-anesthetized cats. At 15 minutes after the trauma, brain tissue was frozen in situ. In animals without visible tissue hemorrhage (Grade 0) and in those with unilateral cerebral contusions involving the cerebral cortex and white matter (Grade 2), regional cerebral metabolite concentrations were measured by enzymatic-fluorometric techniques and edema was tested with an organic gradient. No substantial changes in cerebral metabolite concentrations were observed in head-injured animals without cerebral contusions. In animals with unilateral contusions, the white matter neighboring the tissue hemorrhage had an increase in lactic acid and a decrease in phosphocreatine as compared to values from corresponding areas on the contralateral side, and in control and Grade 0 animals. The cerebral cortex adjacent to tissue hemorrhage had a variable response that ranged from metabolite concentrations within normal ranges to marked decreases in high-energy phosphates and increases in lactic acid. Metabolites of the cortex and white matter contralateral as well as distant to contusion were not statistically different from values of control animals. Changes in several metabolites correlated well with the magnitude of edema. It is concluded that focal metabolic alterations can occur shortly after severe blunt head injury, and that these events may contribute to acute traumatic cerebral edema.
Blood flow and autoregulation in rat pituitary gland
Authors: Kemeny Andras A. , Jakubowski Jan A. , Jefferson Anthony A. , Pasztor Emil
Published: May 2009

✓ The authors describe an experimental model that allows dynamic studies of blood flow in the pituitary gland. Twenty-eight male Wistar rats were anesthetized and the pituitary gland was exposed using a parapharyngeal approach. Teflon-coated platinum wire electrodes were placed in the adenohypophysis near the midline and laterally as well as in the parietal cortex and the white matter. Blood flows were measured by the hydrogen clearance method. Baseline values were as follows: 89.9 ± 22 ml/100 gm/min in the medial adenohypophysis, 55.9 ± 8 ml/100 gm/min in the lateral adenohypophysis, 59.2 ± 14 ml/100 gm/min in the parietal cortex, and 28.1 ± 8.9 ml/100 gm/min in the white matter. Effective autoregulation was demonstrated by altering the blood pressure with metaraminol infusion or blood withdrawal. The range of autoregulation was wider in the adenohypophysis than in the cerebral cortex.
Cavitron ultrasonic surgical aspirator and visual evoked potential monitoring for chiasmal gliomas in children
Authors: Albright A. Leland , Sclabassi Robert J.
Published: May 2009

✓ The Cavitron ultrasonic surgical aspirator (CUSA) and intraoperative visual evoked potentials (VEP's) were found to be helpful in treating two children with difficult chiasmal gliomas. Approximately 60% of one tumor and 85% of the other was resected without change in the intraoperative VEP's and with no change in postoperative visual fields or acuity. The CUSA-VEP technique is useful in the infant to “buy time” for brain maturation, delaying or obviating subsequent radiotherapy. This approach may be helpful in the older child to reduce the tumor burden for subsequent chemotherapy. Chiasmal gliomas can be subtotally resected with the CUSA while visual function is monitored by intraoperative VEP's.
Intracranial germ-cell tumors: natural history and pathogenesis
Authors: Jennings Mark T. , Gelman Rebecca , Hochberg Fred
Published: May 2009

✓ The natural history of primary intracranial germ-cell tumors (GCT's) is defined from 389 previously published cases, of which 65% were germinomas, 18% teratomas, 5% embryonal carcinomas, 7% endodermal sinus tumors, and 5% choriocarcinomas. Intracranial GCT's display specificity in site of origin. Ninety-five percent arise along the midline from the suprasellar cistern (37%) to the pineal gland (48%), and an additional 6% involve both sites. The majority of germinomas (57%) arise in the suprasellar cistern, while most nongerminomatous GCT's (68%) preferentially involve the pineal gland (p < 0.0001). The age distribution of afflicted patients is unimodal, centering with an abrupt surge in frequency in the early pubertal years; 68% of patients are diagnosed between 10 and 21 years of age. Nongerminomatous GCT's demonstrate an earlier age of onset than do germinomas (p < 0.0001). Prolonged symptomatic intervals prior to diagnosis are common in germinomas (p = 0.0007), in suprasellar GCT's (p = 0.001), and among females (p = 0.02). Parasellar germinomas commonly present with diabetes insipidus, visual field defects, and hypothalamic-pituitary failure. Nongerminomatous GCT's present as posterior third ventricular masses with hydrocephalus and midbrain compression. Germ-cell tumors may infiltrate the hypothalamus (11%), or disseminate to involve the third ventricle (22%) and spinal cord (10%). Among a subpopulation of 263 conventionally treated patients, two factors were of prognostic significance: 1) histological diagnosis; germinomas were associated with significantly longer survival than nongerminomatous GCT's (p < 0.0001); and 2) staging of the extent of disease; this emphasizes the ominous character of involvement of the hypothalamus (p = 0.0002), third ventricle (p = 0.02), or spinal cord (p = 0.01). Specific recommendations regarding the necessity of histological diagnosis and staging of the extent of disease are made in light of modern chemotherapeutic advances.

The pathogenesis of GCT's may be revealed by their specificity of origin within the positive (suprasellar cistern-suprachiasmatic nucleus) and negative (pineal) regulatory centers for gonadotropin secretion within the diencephalon. The abrupt rise in age distribution at 10 to 12 years suggests that the neuroendocrine events of puberty are an “activating” influence in the malignant expression of these embryonal tumors.
Management of acoustic neuromas, 1978–1983
Authors: Harner Stephen G. , Ebersold Michael J.
Published: May 2009

✓ The surgical aspects of 162 consecutive procedures for removal of acoustic neuromas, performed from 1978 through 1983, are reviewed. Nearly all of the procedures were done through a retrosigmoid suboccipital craniectomy. Most used the combined skills of a neurosurgeon and an otological surgeon. Total tumor removal was accomplished in 98% of cases. There have been two recurrences and one postoperative death. The facial nerve was preserved in 81% of procedures. Facial function returned in nearly all of these patients, but the degree of return was variable. The cochlear nerve was preserved in 55 patients, but hearing was present in only 14. The most common complication was cerebrospinal fluid otorhinorrhea (12%); about half of these patients required a secondary procedure. Other complications were meningitis (5%), aspiration (3%), and hemorrhage (2%). During the period reviewed, several changes occurred in management of this disorder. These procedures are now being done by a surgical team. The neurosurgeon performs the intracranial work and the otological surgeon accomplishes the temporal bone dissection. Most patients undergo the operation in the supine rather than the sitting position. During the operation, the facial nerve is monitored continuously by electromyography with intermittent bipolar stimulation. There appears to be continuing improvement in the management of these patients.
Stenotic and occlusive disease of the venous drainage system of deep brain AVM's
Authors: Viñuela Fernando , Nombela Luis , Roach Margot R. , Fox Allan J. , Pelz David M.
Published: May 2009

✓ Angiograms obtained prior to treatment in 53 cases of deep-seated cerebral arteriovenous malformations (AVM's) were retrospectively analyzed with particular attention to the topography of the AVM nidus and the venous drainage. The location of the lesion was determined by a combination of angiography and computerized tomography. Twenty-seven AVM's involved the basal ganglia and thalamus, 12 were located in the corpus callosum, six were intraventricular, and eight involved the mesencephalon and brain stem. Forty-one patients (77.3%) presented with intracranial hemorrhage. Vessel wall irregularities and/or stenosis of the system of the vein of Galen were observed in 14 cases, and occlusion of the deep venous system was present in seven cases. These AVM's showed numerous collateral venous pathways through enlarged medullary and cortical regional veins. There was dominant participation of the basal vein of Rosenthal in all cases. Unique local hemodynamic factors produced by the convergence of the draining veins of the AVM's into the vein of Galen and straight sinus may lead to a higher incidence of stenosis and/or occlusion of the venous drainage. The relatively high incidence of intracranial hemorrhage in these deep-seated AVM's may suggest a relationship between an increased incidence of intracranial bleeding and impaired venous outlets.
Successful management of an intracranial arteriovenous malformation by conventional irradiation
Authors: Tognetti Francesco , Andreoli Alvaro , Cuscini Anna , Testa Claudio
Published: May 2009

✓ The reduction of an intracranial arteriovenous malformation (AVM) by conventional radiation therapy is described in a patient who refused surgery. The 2-year follow-up angiogram documented nearly complete obliteration of the nidus of the AVM, accompanied by progressive narrowing of the arteries supplying the lesion. The scanty literature dealing with this form of treatment is summarized.
Acute cerebral revascularization
Authors: Diaz Fernando G. , Ausman James I. , Mehta Bharat , Dujovny Manuel , de los Reyes Raul A. , Pearce Jeffrey , Patel Suresh
Published: May 2009

✓ Fifteen patients evaluated for acute cerebral ischemia underwent acute cerebral revascularization between March, 1979, and May, 1983. Clinical presentation included crescendo transient ischemic attacks (TIA's) in eight cases, progressing neurological dysfunction in three cases, and completed nonfluctuating deficits in four cases. Nine patients received intravenous heparin but did not improve neurologically. The patients with crescendo TIA's were operated on within 4 hours of their last event; those with progressing deficits were operated on while the deficit was developing, and those with established deficits were operated on 4, 6, 9, and 12 hours, respectively, after the event began. The clinical picture for 10 patients had resolved within 10 hours after surgery. One patient with crescendo TIA's, two with progressing deficits, and two with established deficits had postoperative residual deficits, of which three were mild and two severe. One patient, who had a saphenous vein graft to the middle cerebral artery, developed an intracerebral hematoma. In this prospective noncontrolled nonrandomized study, acute cerebral revascularization was performed safely, had limited risks, and offered the potential to help some patients. Further controlled randomized studies are indicated.
The lateral spinal artery of the upper cervical spinal cord
Authors: Lasjaunias Pierre , Vallee Bernard , Person Hervé , Ter Brugge Karel , Chiu Ming
Published: May 2009

✓ The lateral spinal artery corresponds to the most rostral extent of the posterolateral arterial axis of the spinal cord. It supplies the posterior and lateral aspects of the spinal cord, and courses anterior to the posterior roots of the upper cervical spinal nerves (C-1 to C-4), and posterior to the dentate ligament. The lateral spinal artery anastomoses rostrally with the branches of the posterior inferior cerebellar artery (PICA) at the restiform body and laterally with the extraspinal arteries at the emergence of each nerve. It may originate either from the vertebral artery or from the PICA lateral to the medulla. Certain variations will cause an unusual but normal enlargement of the vessel in a specific portion of its course; these variations include vertebral artery duplication, a C-1 or C-2 vertebral origin of the PICA, a C-1 or C-2 occipital origin of the PICA, and an intradural course of the vertebral artery at C-2. Knowledge of these variations in the arterial supply to the area allows for an understanding of the different anatomic peculiarities present and their angiographic importance.
Perforating branches of the middle cerebral artery
Authors: Marinković Slobodan V. , Kovačević Miroslav S. , Marinković Jelena M.
Published: May 2009

✓ Perforating branches of the middle cerebral artery (MCA) were examined under magnification in 50 formalin-fixed brain hemispheres. Perforating vessels varied in number from three to 18, with an average of nine. The greater the number of vessels, the smaller was their diameter. In this study, the perforating arteries were divided into medial, middle, and lateral groupings. Those in the medial group usually arose directly from the MCA main trunk close to the carotid bifurcation. There were usually three vessels in the middle group, which originated not only from the MCA trunk, but also from the MCA collateral (cortical) branches. Common stems, when present, gave rise to individual perforating vessels and occasionally to thin olfactory and insular rami. Perforating arteries in the lateral group varied from one to nine in number. In addition to an origin from the MCA trunk, they also arose from cortical branches supplying the frontal and temporal lobes. The fact that lateral perforating vessels often originated from division sites and from terminal branches of the MCA is of clinical significance, because aneurysms are more commonly located at the MCA bifurcation. Anastomoses were not found among the perforating arteries. In two specimens, a fusion between a perforating artery and the MCA trunk was noted. Since the perforating vessels are obviously end arteries, injury to them must be avoided during operations for MCA aneurysms.
Recirculation model following MCA occlusion in rats
Authors: Shigeno Taku , Teasdale Graham M. , McCulloch James , Graham David I.
Published: May 2009

✓ A new model for establishing a successful and consistent arterial recirculation has been devised following middle cerebral artery (MCA) occlusion in the rat. A snare ligature was introduced at the stem of the MCA just distal to the lenticulostriate branches, and occlusion and recirculation were performed by pulling and releasing the thread. This method had an advantage over the use of a small clip which caused damage to the artery without good recirculation. Study of local cerebral blood flow using carbon-14 (14C)-iodoantipyrine, of cerebrovascular permeability using 14C-aminoisobutyric acid, and of brain-water content using the microgravimetric technique was performed upon recirculation following various periods of occlusion and compared with the results in permanent ischemia. A reactive hyperemia was noted within the previously ischemic area immediately upon recirculation following either a 30-minute or a 2-hour ischemic period. One or 2 hours later, delayed hypoperfusion developed in this region, but the circulation over the periphery of the ischemic area recovered well. Cerebrovascular permeability was not, however, altered during the time courses studied. Topographic changes in tissue specific gravity were compared between permanent and transient ischemia in the corresponding time-courses. Although there was a greater decrease in tissue specific gravity following recirculation when the ischemic period was maintained longer, edema formation was resolved by recirculation. Further study is required to determine thresholds of ischemic brain damage and edema formation at recirculation following focal cerebral ischemia.
Diffuse form of primary leptomeningeal gliomatosis
Authors: Kitahara Masakazu , Katakura Ryuichi , Wada Tokuo , Namiki Tsuneo , Suzuki Jiro
Published: May 2009

✓ Primary leptomeningeal gliomatosis is rare, and the diffuse form is even rarer with only three cases reported in the literature. A fourth case is described in this report. Computerized tomography (CT) findings showed hydrocephalus with enhancement of the cerebral cisterns, and analysis of cerebrospinal fluid obtained by lumbar puncture showed many atypical cells. Based on these findings, a diagnosis of leptomeningeal tumor was made. There was some improvement in neurological and CT findings following radiotherapy and chemotherapy.
The pineal gland: anatomy, physiology, and clinical significance
Authors: Erlich Stephanie S. , Apuzzo Michael L. J.
Published: May 2009

✓ Since the discovery of melatonin approximately 25 years ago, there has been intense study regarding the details of the structure and function of the pineal gland. This work is reviewed, with particular emphasis on those aspects of importance to human physiology and disease.
Multiple intracranial aneurysms: determining the site of rupture
Authors: Nehls Daniel G. , Flom Richard A. , Carter L. Philip , Spetzler Robert F.
Published: May 2009

✓ A retrospective hospital chart and radiograph review was performed of all patients with multiple intracranial aneurysms seen over a 52-month period. Sixty-nine patients with a total of 205 aneurysms were studied. Among the patients with aneurysms, the incidence of multiple aneurysms was 33.5%. Multiple aneurysms were much more common in women, with a female to male ratio of 5:1 for all patients and 11:1 for patients with three or more aneurysms. Common locations for multiple aneurysms were the posterior communicating artery (22%), middle cerebral artery (21.5%), anterior communicating artery (12%), and ophthalmic artery (11%). However, locations with the highest probability of rupture were the anterior communicating artery (62%), posterior inferior cerebellar artery (50%), and basilar artery summit (50%). The middle cerebral artery was the least likely site for rupture. In contrast to previous studies, in this series irregularity of contour was more important than size in identifying the site of rupture. Using a simple algorithm outlined in the text, it was possible to identify the site of aneurysm rupture in 97.5% of cases.