bluuebunny/crossref_metadata_2025 huggingface dataset:
A hypothesis for myeloschisis: overgrowth and reopening
Authors: Oi Shizuo , Saya Hideyoshi , Matsumoto Satoshi
Published: May 2009

✓ A hypothesis for embryopathogenesis of myeloschisis is described on the basis of experimental studies analyzing the stage specificity and immunohistochemical/histological characteristics of the exposed neural tissue (placode). Myeloschisis developed in six fetuses among 205 chick embryos treated in various stages with teratogens including ethylnitrosourea, and anticonvulsant and antipyretic agents. All but one case (with associated cephalothoracopagus) demonstrated myeloschisis in the thoracic region with a lamina defect of two and three levels. No fetus was exposed to a teratogen prior to or within Hamburger and Hamilton stage 12 (45 to 49 hours postincubation), when the neuropore closes. Immunohistochemical studies of chick myeloschisis clearly indicated that neuron-specific enolase-positive elements were extremely active only in the overgrown placode, corresponding to the histological findings with Kluver-Barrera's special stain. These findings were compared with observations in a case of myeloschisis in a human neonate. The results of this study imply the possibility of another mechanism for the embryopathogenesis of myeloschisis: namely, the overgrowth and reopening hypothesis.
Giant aneurysms of the vertebral artery
Authors: Sugita Kenichiro , Kobayashi Shigeaki , Takemae Toshiki , Tanaka Yuichiro , Okudera Hiroshi , Ohsawa Michihiko
Published: May 2009

✓ The authors report five cases of surgically treated giant vertebral artery aneurysm. Two giant serpentine aneurysms were managed with aneurysmectomy, a giant semifusiform aneurysm with trapping and partial aneurysmectomy, and the other two saccular giant aneurysms with clipping. Surgical results were satisfactory in all cases. In particular, the two patients who underwent complete aneurysmectomy showed remarkable improvement after the second procedure of a two-stage operation that consisted of initial proximal occlusion and secondary evacuation of clots in the aneurysm when advanced thrombosis was identified. Aneurysmectomy in a two-stage operation was the best treatment for these partially thrombosed giant aneurysms which completely concealed the distal artery under a tight thinned medulla.
Extravasation injury to the hand by intravenous phenytoin
Authors: Rao Venkat K. , Feldman Paul D. , Dibbell David G.
Published: May 2009

✓ Extravasation of intravenous phenytoin can result in serious soft-tissue complications. Three patients are presented, one of whom lost a hand. Assessment of circulation and early decompression fasciotomies may be necessary in such cases. Caution is recommended in the intravenous administration of phenytoin. Infusions at rates of less than 50 mg/min and education of nursing staff about this potential complication will decrease its incidence.
CNS toxicity associated with intraventricular injection of cefazolin
Authors: Manzella John P. , Paul Ronald L. , Butler Ivan L.
Published: May 2009

✓ Three patients who experienced central nervous system toxicity secondary to intraventricular therapy with cefazolin are described. On the basis of this experience it is recommended that cefazolin not be used for intraventricular antibiotic therapy in the treatment of shunt infections.
Percutaneous electrocoagulation of the trigeminal nerve using CT guidance
Authors: Krol George , Arbit Ehud
Published: May 2009

✓ Computerized tomography guidance can be used during placement of an electrode for the ablation of the trigeminal nerve or gasserian ganglion. A combination of a scout view and axial images through the skull base provides adequate visualization of the needle and foramen ovale. This method is recommended in patients who cannot be properly positioned for fluoroscopy or when there is poor visualization of the foramen on conventional radiographs.
Photoradiation therapy and its potential in the management of neurological tumors
Authors: Kaye Andrew H. , Morstyn George , Apuzzo Michael L. J.
Published: May 2009

✓ Photoradiation therapy is a form of local treatment that depends on the selective retention of a photosensitizer, such as hematoporphyrin derivative (HpD), by the tumor followed by treatment with light of an appropriate wavelength to activate the sensitizer in the tumor. The selective uptake of HpD by cerebral tumors has been demonstrated both in laboratory animal model studies and in clinical studies, and selective destruction of intracerebral tumors has been demonstrated in animal glioma models. The biological basis for photoradiation therapy and, in particular, the mechanisms for the selective uptake of the sensitizer into the tumor and the destruction of tumor with photoradiation therapy are discussed. Current evidence suggests that singlet oxygen is the major intermediary leading to cell damage, although other radicals such as hydrogen peroxide and hydroxyl radicals may be involved. Other studies suggest that the initial damage is to the blood vessels, and the tumor subsequently undergoes ischemic changes.

Sixty-four patients treated with photoradiation therapy have been reported in the literature. The initial clinical studies were disappointing in their therapeutic effect but these studies often included treatment of recurrent gliomas and low doses of light were used. Technical advances, particularly in laser technology, have enabled more effective photoradiation therapy and the clinical trials are reviewed.
High-dose barbiturate control of elevated intracranial pressure in patients with severe head injury
Authors: Eisenberg Howard M. , Frankowski Ralph F. , Contant Charles F. , Marshall Lawrence F. , Walker Michael D. , _ _
Published: May 2009

✓ In a five-center study, 73 patients with severe head injury and elevated intracranial pressure (ICP) were randomly assigned to receive either a regimen that included high-dose pentobarbital or one that was otherwise similar but did not include pentobarbital. The results indicated a 2:1 benefit for those treated with the drug with regard to ICP control. When patients were stratified by prerandomization cardiac complications, the advantage increased to 4:1. A multiple logistic model considering treatment and selected baseline variables indicated a significant positive treatment effect of barbiturates, a significant effect of time from injury to randomization, and an interaction of treatment with cardiovascular complications. However, of 925 patients potentially eligible for randomization, only 12% met ICP randomization criteria. The results support the hypothesis that high-dose pentobarbital is an effective adjunctive therapy, but that it is indicated in only a small subset of patients with severe head injury.
Cerebrovascular CO2 reactivity after carotid artery occlusion
Authors: Clifton Guy L. , Haden Halcott T. , Taylor John R. , Sobel Michael
Published: May 2009

✓ Cerebral blood flow (CBF) was measured in 39 men at normocapnia and after 5% CO2 inhalation using the xenon-133 technique. Twenty-three patients had unilateral carotid artery occlusion with no angiographic evidence of contralateral carotid artery stenosis or ophthalmic collateral flow. Eleven of these patients had undergone extracranial-intracranial (EC-IC) bypass surgery. Sixteen age-matched normal men underwent CBF measurements at normocapnia and hypercapnia to provide control data. Mean hemispheric CBF was not different between hemispheres ipsilateral and contralateral to the carotid artery occlusion either in the patients who had undergone bypass surgery or in those with carotid artery occlusion alone. Considering all patients with carotid artery occlusion, mean CO2 reactivity was decreased in the hemisphere ipsilateral to the occlusion as compared to the contralateral hemisphere in both groups. Based on data from normal individuals, a hemispheric difference in CO2 reactivity of more than 0.94%/mm Hg PaCO2 or a global CO2 reactivity of less than 0.66%/mm Hg PaCO2 was considered abnormal for an individual patient. Six of 23 patients with carotid artery occlusion (three with an EC-IC bypass) had global or hemispheric abnormalities in CO2 reactivity. Patients with impaired CO2 reactivity were not distinguishable from other patients by neurological examination, presence of transient ischemic attacks, or evidence of infarction on computerized tomography scanning. This test was safe and simple to perform and may be a useful means of detecting impaired cerebrovascular collateral reserve capacity. If impaired CO2 reactivity after carotid artery occlusion proves to be associated with a high risk of subsequent stroke, the test would provide a physiological basis for selecting a subgroup of patients who could be helped by cerebral revascularization.
Long-term efficacy of microvascular decompression in trigeminal neuralgia
Authors: Burchiel Kim J. , Clarke Hadley , Haglund Michael , Loeser John D.
Published: May 2009

✓ Forty patients were followed for an average period of 8½ years after 44 consecutive suboccipital craniotomies for trigeminal neuralgia. Among these patients, 36 had microvascular decompression (MVD) of the nerve, four had repeat trigeminal rhizotomy after MVD was not successful in controlling their pain, and four had primary trigeminal rhizotomies. Of the 36 patients undergoing MVD, 17 (47%) experienced recurrent postoperative neuralgic pain: in 11 (31%) pain recurrence was major, and in six (17%) it was minor. Among the eight patients undergoing rhizotomy, four (50%) had major pain recurrences and one (13%) had a minor recurrence, for a 63% total recurrence rate. There was a strong statistical relationship between an operative finding of arterial cross-compression of the nerve and long-term complete pain relief. Patients with other compressive pathology (related to veins or bone structures) did not on the average fare as well. Despite this, there appeared to be no point in time in the postoperative interval when the patient could be considered “cured.” Major recurrences averaged 3.5% annually, and minor recurrences averaged 1.5% annually. The implications of these findings for the treatment of trigeminal neuralgia and the current understanding of the mechanism of MVD for this disorder are discussed.
Intrasellar cysticercosis
Authors: Del Brutto Oscar H. , Guevara Jaime , Sotelo Julio
Published: May 2009

✓ Eight patients with cysticerci located inside the sella turcica are presented, and the clinical and radiological features of this rare form of neurocysticercosis are discussed. Clinical features included nonspecific ophthal-mological and endocrinological disturbances similar to those produced by other sellar lesions. Computerized tomography (CT) usually showed a hypodense mass that simulated either a cystic tumor or an arachnoid cyst. Cerebrospinal fluid (CSF) findings were also nonspecific, as immunological reactions to cysticercosis were most often negative when inflammation was limited to suprasellar and intrasellar regions. An incorrect diagnosis of tumor was frequent in these cases. In contrast, when intrasellar cysticercosis was associated with other forms of neurocysticercosis, proper integration of CT and CSF data permitted an accurate diagnosis. Cysticercosis should be suspected in patients with hypodense juxtasellar lesions living in geographical areas where this disease is endemic. Prompt surgical resection of cysticerci will avoid irreversible damage to visual function.
Isovolemic hemodilution in experimental focal cerebral ischemia
Authors: Tu Yong-Kwang , Heros Roberto C. , Candia Guillermo , Hyodo Akio , Lagree Karen , Callahan Ronald , Zervas Nicholas T. , Karacostas Dimitris
Published: May 2009

✓ A total of 76 splenectomized dogs were entered in a study of the value and effects of isovolemic hemodilution. Of these, seven were not included in the analysis because of technical errors. Of the remaining 69 dogs, 35 were treated with hemodilution; 28 were subjected to a 6-hour period of temporary occlusion of the distal internal carotid artery and the proximal middle cerebral artery, and seven underwent a sham operation only, with arterial manipulation but no occlusion. The other 34 dogs were not subjected to hemodilution; 26 of these underwent temporary arterial occlusion and eight had a sham operation only. In each group the animals were about equally divided into 1) an acute protocol with regional cerebral blood flow measurements by a radioactive microsphere technique and sacrifice at the end of the acute experiment, and 2) a chronic protocol with survival for 1 week to permit daily neurological assessment and final histopathological examination but without blood flow measurements. Isovolemic hemodilution was performed about 1 hour after the arterial occlusion or sham operation and was accomplished by phlebotomy and infusions of low molecular weight dextran to bring the hematocrit to a level of 30% to 32%. This treatment resulted in a very significant reduction in viscosity and fibrinogen levels. The decrease in hematocrit lasted throughout the week in the animals in the chronic protocol. The decrease in viscosity correlated almost linearly with the decrease in hematocrit. There was a slight decrease in systemic arterial pressure with hemodilution but there were no significant changes in central venous pressure or in pulmonary arterial or wedge pressure. There was a slight decrease in cardiac index in both the hemodilution and control groups, which may have been due to the effects of barbiturate anesthesia. There was a slight increase in the measured blood volume in both groups, which was probably artifactual and related to the method of calculation. Intracranial pressure increased significantly with time in all animals subjected to arterial occlusion, but this increase was less severe in the hemodilution group. There was no significant change in intracranial pressure in sham-operated animals, whether hemodiluted or not. The results of cerebral blood flow measurements, assessment of neurological condition, and measurement of infarct size are given in Part 2 of this report.
Isovolemic hemodilution in experimental focal cerebral ischemia
Authors: Tu Yong-Kwang , Heros Roberto C. , Karacostas Dimitris , Liszczak Ted , Hyodo Akio , Candia Guillermo , Zervas Nicholas T. , Lagree Karen
Published: May 2009

✓ Seventy-six splenectomized dogs were entered in a study of the value and effects of isovolemic hemodilution. Of these, seven were not included in the analysis because of technical errors. Of the remaining 69 dogs, 35 were treated with hemodilution; 28 were subjected to a 6-hour period of temporary occlusion of the distal internal carotid artery and the proximal middle cerebral artery, and seven underwent a sham operation only, with arterial manipulation but no occlusion. The other 34 dogs were not subjected to hemodilution; 26 of these underwent temporary arterial occlusion and eight had a sham operation only. In each group the animals were about equally divided into 1) an acute protocol with regional cerebral blood flow measurements by a radioactive microsphere technique and sacrifice at the end of the acute experiment, and 2) a chronic protocol with survival for 1 week to permit daily neurological assessment and final histopathological examination but without blood flow measurements. The general experimental protocol, the hemodynamic and rheological measurements, and the changes in intracranial pressure are described in Part 1 of this report.

In the animals with arterial occlusion, blood flow decreased significantly in the territory of the ischemic middle cerebral artery. This decrease was partially reversed by hemodilution in the animals so treated. When the changes in blood flow before and after hemodilution in treated animals are compared with the changes at equivalent times in animals without hemodilution, the increases in flow in the gray matter of the ischemic hemisphere brought about by hemodilution are statistically significant. The neurological condition of the animals in the chronic protocol (sacrificed 1 week after occlusion) with hemodilution, as evaluated by daily neurological assessment, was significantly better than that of the control animals.

In the animals sacrificed acutely (8 hours after arterial occlusion), the volume of infarction as estimated by the tetrazolium chloride histochemical method was 7.36% of the total hemispheric volume in the control animals and 1.09% in the hemodiluted animals, showing a statistically significant difference (p < 0.005). In the chronic animals these values were 9.84% and 1.26%, respectively (p < 0.005), as calculated by fluorescein staining. By histopathological examination the volume of infarction in the chronic animals was calculated as 10.92% in the control animals and 1.20% in the hemodiluted animals (p < 0.005). There was good correlation between the size of infarction and the decrease in hematocrit and viscosity, and excellent correlation between the size of infarction estimated by fluorescein and that determined by histopathological examination in each animal in the chronic group.
The pathogenesis of spinal epidural abscess: microangiographic studies in an experimental model
Authors: Feldenzer John A. , McKeever Paul E. , Schaberg Dennis R. , Campbell John A. , Hoff Julian T.
Published: May 2009

✓ An experimental model of spinal epidural abscess was developed in rabbits by injecting Staphylococcus aureus into the posterior thoracolumbar epidural space. This model has been shown to reproduce the neurological, bacteriological, and radiological aspects of the human disease. In this study, the effect of the infectious epidural mass on the vasculature of the spinal cord in paraplegic rabbits was studied using microangiographic techniques. The normal vascular anatomy of the rabbit spinal cord was defined in control experiments. Vascular proliferation was demonstrated in the epidural space surrounding the abscesses. Anterior and paired posterior spinal arteries remained patent in paraplegic rabbits with mild or moderate spinal cord compression and in some cases of severe compression. In animals with severe compression, the anterior epidural venous plexus remained patent, but the dorsal spinal vein was occluded. Occlusion of perforating arteries occurred only with extreme spinal cord compression. These data indicate that the initial neurological deficit associated with experimental spinal epidural abscess is not due to vascular thrombosis.
Therapeutic embolization of an ascending pharyngeal artery-internal jugular vein fistula
Authors: Guglielmi Guido , Guidetti Giulio , Mori Stefania , Silipo Pasquale
Published: May 2009

✓ The authors report a case of an arteriovenous fistula between the ascending pharyngeal artery and the internal jugular vein. The importance of an exact diagnosis and some precautions to be taken during therapeutic embolization are emphasized, as well as the need for superselective cannulation of the feeding artery. The problem of differential diagnosis with glomus tumors is discussed, and a brief mention is made of the anatomy of the jugular foramen and embryology of these tumors. Only one similar case treated by embolization with solid particles was found in the literature. To date, embolization using solid particles rather than liquid agents appears to be the best treatment of fistulas of this type.
Anterior cervical disc herniation
Authors: Bernardo Kerry L. , Grubb Robert L. , Coxe William S. , Roper Charles L.
Published: May 2009

✓ A 39-year-old man with an extrinsic esophageal lesion was found to have an anterior herniation of a soft degenerated cervical disc. Only two cases of symptomatic anterior cervical disc herniation have been reported previously. Dysphagia produced by anterior cervical osteophytes is more common and is a recognized clinical entity. Asymptomatic anterior cervical disc herniation may play a key role in the pathogenesis of anterior cervical osteophytes.
A serrated suction tip for tumor removal
Authors: Shibuya Masato , Suzuki Yoshio , Nakane Toshichi
Published: May 2009

✓ A serrated suction tip with a variety of diameters and serrations has been developed for the microsurgical removal of tumors. These tips can dissect and aspirate tumor tissue, cerebrospinal fluid, or blood simultaneously, and the degree of suction can be controlled by the pressure of the tip against the tumor.
Carotid control for intracranial aneurysms
Authors: Heifetz Milton D.
Published: May 2009

✓ A new clamp with a flexible cable control mechanism for temporary intraoperative occlusion of the cervical internal carotid artery is described.
Treatment results of juvenile pilocytic astrocytoma
Authors: Wallner Kent E. , Gonzales Michael F. , Edwards Michael S. B. , Wara William M. , Sheline Glenn E.
Published: May 2009

✓ Treatment results for 36 patients with juvenile pilocytic astrocytoma treated from 1942 through 1985 at the University of California, San Francisco, were reviewed. Twenty-two tumors were located in the posterior fossa, 10 were in the hypothalamic region, and four were in the cerebral hemispheres. Twenty-eight patients were less than 18 years of age. The overall survival rate was 83% and 70% at 10 and 20 years, respectively. All 12 patients who had total tumor resection remain disease-free; only two of the 12 received postoperative irradiation. The 10- and 20-year freedom-from-progression for the 19 patients who had incomplete resection and received at least 40 Gy of postoperative irradiation was 74% and 41%, respectively. All patients who failed treatment had local recurrence. One patient developed diffuse meningeal seeding, after four local recurrences in the posterior fossa over a 23-year period. Six patients failed treatment and had a repeat biopsy at the time of recurrence or at postmortem examination, and three showed histological progression of the tumor to an anaplastic astrocytoma. Based on this study and others in the literature, a protocol has been adopted whereby patients who have total tumor resection are not treated with postoperative irradiation. Patients who have incomplete tumor resection and are older than 3 years of age are currently treated with postoperative partial-brain irradiation, to a dose of 45 to 60 Gy. In general, young children with incomplete resection are followed closely with computerized tomography or magnetic resonance imaging and are treated with chemotherapy or irradiation if tumor progression is documented.
Recurrent spinal cord injury without radiographic abnormalities in children
Authors: Pollack Ian F. , Pang Dachling , Sclabassi Robert
Published: May 2009

✓ Spinal cord injury without radiographic abnormality is a well-known entity in the pediatric age group. Agerelated elasticity of the vertebral ligaments as well as immaturity of the osseous structures in the pediatric spine allow momentary subluxation in response to deforming forces. The resultant neurological injuries range from transient dorsal column dysfunction to complete cord transection. Between 1960 and 1985, 42 such injuries were treated at the Children's Hospital of Pittsburgh. Management of these radiographically occult spinal cord injuries consisted of cervical immobilization for 2 months in a hard collar and restriction of contact sports. Recurrent cord injury occurred in eight cases during the 2-month immobilization period. A clearly defined traumatic episode was identified in seven of the eight patients, although in four children the recurrent trauma to the spine was trivial. Five of the children removed their collars briefly before the second injury, and two children incurred reinjury with the hard collar in place. The remaining child was too young for hard-collar immobilization, and recurrent neurological deterioration occurred during sleep. Serial flexion-extension films failed to detect frank instability in any of the eight cases. The children most susceptible to reinjury were those who sustained mild or transient neurological deficits from an initial cord injury and who rapidly resumed normal activities. Radiographically occult spinal instability resulting from the initial injury to the vertebral and paravertebral soft tissues presumably made these children vulnerable to recurrent spinal cord injury, often from otherwise insignificant trauma. During the last 21 months, 12 additional children have been managed with a more stringent protocol combining neck immobilization in a rigid cervical brace for 3 months and restriction of both contact and noncontact sports, together with a major emphasis on patient compliance. With this new protocol, no recurrent cord injuries have been documented.
MR imaging as predictor of delayed posttraumatic cerebral hemorrhage
Authors: Tanaka Tokutaro , Sakai Tsuneo , Uemura Kenichi , Teramura Atsushi , Fujishima Ichiro , Yamamoto Takamichi
Published: May 2009

✓ The occurrence of delayed traumatic intracerebral hemorrhage or hematomas was predicted in four patients by T2-weighted magnetic resonance (MR) imaging. From June, 1986, through February, 1987, 42 patients with head injury were admitted to the Neurosurgical Service of the Seirei Mikatabara General Hospital. Cerebral contusion was suspected in six of these patients. Although the initial computerized tomography (CT) scans showed no cerebral parenchymal lesion, the initial symptoms were more serious than might have been expected from the initial CT findings and/or because their initial CT scans showed intracranial extracerebral hemorrhage. In all six, the initial CT scans were obtained within 2 hours after the injury and were followed by MR imaging. In four patients, T2-weighted MR images revealed areas of increased signal intensity in the cerebral parenchyma, where hemorrhagic changes were subsequently demonstrated by follow-up CT scans. In the remaining two, T2-weighted MR images showed no parenchymal lesion and subsequent CT scans confirmed the absence of hemorrhagic change; these two patients were discharged from the hospital without neurological deficits. It is concluded that MR imaging is useful in predicting delayed hemorrhages.
Results of a randomized trial of vancomycin prophylaxis in craniotomy
Authors: Blomstedt Göran C. , Kyttä Juha
Published: May 2009

✓ A single prophylactic dose of vancomycin was given in 143 supratentorial craniotomies with a bone flap and 26 suboccipital craniotomies. No antimicrobial agents were given to two similar groups of patients: 172 with supratentorial craniotomy and 19 with suboccipital craniotomy. The infection rate in the vancomycin groups was significantly lower (p < 0.013), and bone-flap infections alone, the most common infection after supratentorial craniotomy, were significantly fewer (p < 0.042). Antimicrobial prophylaxis is recommended only for selected high-risk groups. Since a bone flap is devascularized, its resistance to infection is reduced and, once infected, it usually requires surgical removal. Patients undergoing craniotomy with a bone flap therefore form a high-risk group, and antimicrobial prophylaxis is justified.
Dural ectasia and the Marfan syndrome
Authors: Stern W. Eugene
Published: May 2009

✓ The not-uncommon spinal abnormalities associated with Marfan's syndrome rarely undergird clinical problems, and neurological features accompanying such bone abnormalities are rare. In such unusual circumstances it is a widened vertebral canal that attracts attention: the substrate of such widening is dural ectasia with bone erosion, presumably due to hydraulic forces operating via the cerebrospinal fluid (CSF).When neural symptoms or findings do occur they may be related to stretching and traction mechanisms. This study of a symptomatic patient defined with reasonable clarity the abnormal anatomy, and some neurological symptom relief was achieved by attempting to alter the CSF dynamics. The relevant literature has been sampled to elucidate the condition.
Stereotaxic implantation of dispersed cell suspensions into brain
Authors: Plunkett Robert J. , Weber Richard J. , Oldfield Edward H.
Published: May 2009

✓ The application of several recent advances in cell biology, brain implantation, and cell-mediated tumor immunotherapy requires successful and reproducible placement of viable cell suspensions into brain. Stereotaxic implantation is being used to inject cytotoxic lymphocytes into gliomas and to replace dopaminergic cells in parkinsonian models. Systematic assessment of the factors that influence success in implantation of cell suspensions into solid tissues is needed.

A model was developed for investigation of stereotaxic implantation using radiolabeled rat lymphokine-activated killer (LAK) cells. Anesthetized rats received microliter injections of cell suspension into the right caudate nucleus. The injection volume, cell concentration, infusion rate, and needle size were varied systematically. The animals were sacrificed 1 hour after injection; the brain was removed and sectioned, and the radioactivity was counted. Three aliquots of the suspension were injected into counting tubes for control analysis. Recovery of radioactivity was expressed as the percent of mean counts per minute (cpm) in the right frontal lobe/mean cpm in the three control tubes. To assess the viability of implanted cells, the right frontal region was mechanically dissociated in media and centrifuged, and the pellet and supernatant were counted. By using small needles and slow infusion of volumes of 10 µl or less, 85% to 90% of the radioactivity was recovered in the caudate nucleus. At least half of the implanted cells were viable. Consistent, accurate implantation of dispersed cells into brain over a range of volumes, cell concentrations, infusion rates, and needle sizes was achieved.
Alterations in endothelium-dependent responsiveness of the canine basilar artery after subarachnoid hemorrhage
Authors: Kim Phyo , Sundt Thoralf M. , Vanhoutte Paul M.
Published: May 2009

✓ To investigate the alteration of endothelium-dependent responses in chronic vasospasm after subarachnoid hemorrhage (SAH), experiments were carried out in the double-hemorrhage canine model. After the presence of vasospasm was confirmed by cerebral angiography on Days 0 and 7, pharmacological studies on the basilar artery were conductedin vitroon Day 8. In the SAH group, endothelium-dependent relaxation was abolished in response to arginine vasopressin and was significantly reduced in response to thrombin. Endothelium-independent relaxation in the SAH group was preserved in response to papaverine and was minimally reduced in response to sodium nitroprusside. Endothelium-dependent contraction in response to arachidonic acid, acetylcholine, the calcium ionophore A23187, adenosine diphosphate, mechanical stretching, and hypoxia persisted in the SAH group. The maximal contraction to KCl and uridine triphosphate, which is endothelium-independent, was diminished in the SAH group, but no changes in sensitivity were noted in the concentration-response relationships. A significant correlation was observed between the degree of vasospasm determined angiographically and the loss of endothelium-dependent relaxation. The loss of endothelium-dependent relaxation and the persistence of endothelium-dependent contraction suggest that the deterioration in the endothelium-dependent responses may be an important component in the pathogenesis of cerebral vasospasm.
Further characterization of malignant glioma-derived vascular permeability factor
Authors: Criscuolo Gregory R. , Merrill Marsha J. , Oldfield Edward H.
Published: May 2009

✓ The nature of vascular permeability factor (VPF) activity derived from serum-free conditioned medium containing cultured human malignant glial tumors has been further investigated. A 1000-fold purification was accomplished by sequential heparin-Sepharose affinity chromatography and high-performance liquid chromatography gel filtration chromatography steps. Vascular permeability factor activity falls into a molecular weight range of 41,000 to 56,000 D. Activity is bound to hydroxylapatite, carboxymethyl-Sepharose, phenyl-Sepharose, and heparin-Sepharose, whereas little or no activity was bound to diethylaminoethyl-Sephacel. Vascular permeability factor activity is trypsin-and pepsin-sensitive but is unaffected by treatment with ribonuclease A. This suggests that VPF is a hydrophobic, positively charged (cationic) polypeptide with a potentially biologically significant affinity for heparin. As most proteins are negatively charged (anionic) and have no affinity for heparin, a significant advantage was gained by performing these purification steps.

The activity of VPF is not inhibited by coinjection of conditioned medium with soybean trypsin inhibitor; or hexadimethrine (both known antagonists of tissue plasminogen activator, Hageman factor, and serum kallikrein); or aprotinin (an antagonist of both plasmin and tissue kallikrein); or phenylmethanesulfonyl fluoride (a serine esterase (elastase) inhibitor); or pepstatin-A (an acid protease inhibitor which inactivates vascular permeability-inducing leukokinins). These data, together with the fact that VPF is produced and released into serum-free media, provides substantial evidence against it being one of the more commonly known serum-derived permeability mediators. Treatment with dithiothreitol inhibited VPF activity, indicating the presence of at least one essential disulfide bond in this molecule. Inhibition by dexamethasone of VPF expression in cultured malignant glial cells appears to be selective. Dexamethasone-induced inhibition of VPF was dose-responsive and was not associated with a parallel inhibition of cellular protein synthesis as determined by tritiated leucine incorporation into trichloroacetic acid-precipitable material. Inclusion of dexamethasone in the culture medium was not associated with altered cell viability or cell number.

A series of in vivo studies confirmed the inhibition of VPF activity in test animals pretreated with dexamethasone. This steroid-induced inhibition was partially reversed by treatment of test animals with actinomycin D prior to exposure to dexamethasone. The latter finding suggests that dexamethasone exerts its inhibitory action by induction of de novo protein synthesis.
Cavernous hemangioma of the optic nerve
Authors: Maruoka Nobuhiko , Yamakawa Yuzo , Shimauchi Masaki
Published: May 2009

✓ A case of cavernous hemangioma of the optic nerve of a 24-year-old pregnant woman is reported. The visual disturbance with subacute onset was thought to be related to the delivery of a child. The lesion was totally removed through the subfrontal approach, resulting in satisfactory recovery of visual symptoms. Cavernous hemangioma involving the optic nerve and chiasm is extremely rare. Only two similar cases have been reported previously.
Early versus late intracranial aneurysm surgery in subarachnoid hemorrhage
Authors: Chyatte Douglas , Fode Nicolee C. , Sundt Thoralf M.
Published: May 2009

✓ The management results in 244 patients admitted to one institution within 3 days of aneurysmal subarachnoid hemorrhage (SAH) from January, 1979, to December, 1985, were analyzed with respect to the timing of surgical intervention. Twenty-six patients died prior to surgery. Patients surviving to surgery were divided into three groups according to the interval between preadmission SAH and surgery: 0 to 3 days (85 cases), 4 to 9 days (83 cases), and 10 or more days (50 cases). Of the patients who were categorized neurologically into Botterell Grades 1 and 2 (Hunt and Hess Grades I to III) on admission, 87% had an excellent or good result on follow-up evaluation. Patients undergoing surgery 0 to 3 days after SAH had a statistically significant increase in the incidence of postoperative ischemic symptoms (p < 0.005), which was balanced by similar complications preoperatively in the 10-day post-SAH surgical group. Most rebleeds occurred before admission but delaying surgery did increase the risk of rebleeding in the hospital (p < 0.0005). Management morbidity and mortality occurred primarily as a direct result of a severe initial hemorrhage; thus, the measured benefits of early surgery were less than might have been predicted.
Percutaneous retrogasserian glycerol rhizolysis in the management of trigeminal neuralgia
Authors: Burchiel Kim J.
Published: May 2009

✓ Sixty patients with trigeminal neuralgia or atypical facial pain were followed for an average of 1 year after percutaneous retrogasserian glycerol rhizolysis. The procedure was initially effective in relieving pain in 80% of the patients with typical trigeminal neuralgia and symptomatic trigeminal neuralgia secondary to multiple sclerosis. However, life-table analysis indicated that 50% of this group had persistence or recurrence of pain within 18 months after the operation. Percutaneous retrogasserian glycerol rhizolysis was ineffective in relieving atypical trigeminal neuralgia or atypical facial pain. Minor complications occurred in 23% of patients, and major morbidity was seen in 1.6%. Facial sensory loss which persisted for more than 1 month was found in 72% of patients, corneal hypesthesia occurred in 15%, and an additional 7% had corneal anesthesia. The data indicate that the success of percutaneous retrogasserian glycerol rhizolysis in relieving trigeminal neuralgia is directly related to the production of facial sensory loss.
Hearing loss after microvascular decompression for trigeminal neuralgia
Authors: Fritz Wolfram , Schäfer Jürgen , Klein Heinz J.
Published: May 2009

✓ Of 21 patients examined audiometrically before and after microvascular decompression of the trigeminal nerve, five (23.8%) had postoperative hearing impairment. A middle ear effusion was found in three (14.3%), probably caused by mastoid cell opening. A retrocochlear lesion in the other patients was caused by transferred pressure on the cochlear nuclei or by traction on the nerve. Vascular perfusion problems were also possible but are difficult to document.
Tethered cord syndrome of delayed onset following repair of myelomeningocele
Authors: Tamaki Norihiko , Shirataki Kunio , Kojima Noriaki , Shouse Yoshiteru , Matsumoto Satoshi
Published: May 2009

✓ Nine (15%) of 60 patients with repaired myelomeningocele exhibited late deterioration of neurological function with a tethered cord syndrome. Dense adhesions at the lowest laminae and at the site of previous repair were the most common findings at surgery. Postoperatively, 71% of the patients improved.

Magnetic resonance (MR) imaging was performed in 29 of the 60 patients. Eight of these 29 patients exhibited a tethered cord syndrome. The MR images in all patients showed a low-lying conus fixed at the site of previous repair, irrespective of the presence or absence of a tethered cord syndrome. The MR images were classified into two groups depending upon the site of adhesions: Group A had potential sites of tethering at the ventral aspect of the last laminae and at the site of previous repair, and Group B showed the adhesion point only at the site of previous repair. Most patients with a tethered cord syndrome were found to be in Group A; conversely, most patients without the syndrome were in Group B. An enlarged low conus was seen in symptomatic patients more commonly than in those without this syndrome.

It is concluded that the presence of adhesions specifically at the last laminae as well as a widened low-lying conus may be the cause of tethered cord syndrome in patients with repaired myelomeningoceles. A clear understanding of the tethering process and preoperative evaluation of potential sites of tethering, based on the MR findings, are very important for planning surgery. The release of adhesions at the lowest laminae by laminectomy appeared essential for improvement.
Effects of nimodipine on the production of thromboxane A2 following total global cerebral ischemia
Authors: Haddon W. Scott , Prough Donald S. , Kong Daniel , Petrozza Patricia
Published: May 2009

✓ To clarify the contribution of vasoconstrictor prostaglandins to the hypoperfusion state typically following total global cerebral ischemia, 14 mongrel dogs were subjected to 11 minutes of global cerebral ischemia. They were then randomly assigned to receive either no treatment or an intravenous bolus of the calcium channel blocker nimodipine, 10 µg/kg, 15 minutes after ischemia followed by a continuous infusion of nimodipine, 1.0 µg/kg/min. Thromboxane (Tx) A2 production, as measured by cerebral venous levels of TxB2 (the stable metabolite of TxA2) increased similarly in the two groups. In contrast to previous studies, mean postischemic cerebral blood flow did not increase sufficiently in the nimodipine-treated group to achieve statistical significance. These data suggest that the improved neurological outcome associated with nimodipine treatment following global cerebral ischemia does not relate to reduced levels of the prostaglandin precursor arachidonate.
A light and electron microscopic and immunohistochemical study of human arachnoid villi
Authors: Kida Shinya , Yamashima Tetsumori , Kubota Toshihiko , Ito Haruhide , Yamamoto Shinjiro
Published: May 2009

✓ The structure of human arachnoid villi was investigated by light and electron microscopy with the aid of immunohistochemical techniques. The human arachnoid villi examined were basically composed of four portions: a fibrous capsule, an arachnoid cell layer, a cap cell cluster, and a central core. The arachnoid cell layer encompassing the central core was mostly covered by the thin fibrous capsule with an endothelial investment. However, the fibrous capsule was often absent at the apical portion of the villus and a factor VIII-related antigen stain failed to confirm the investment of endothelial cells. Instead, the arachnoid cell layer abutted directly upon the lumen of a lateral lacuna or the sinus. The arachnoid cell layer was thickened in places, forming cap cell clusters; it usually consisted of outer and inner zones. On vimentin staining, the former was slightly positive while the latter was strongly positive. The central core contained a network of arachnoid cells intermingled with connective tissue fibers and was in continuity with the cranial subarachnoid space. Electron microscopy showed that the arachnoid cells contained a larger number of intermediate filaments in the inner zone than the outer zone. Ultrastructural immunohistochemical localization showed that vimentin was localized at the intermediate filaments and desmosomal plaques of the arachnoid cells. The arachnoid cells showed a marked variety in both the cell forms and the number of intermediate filaments or desmosomes, depending on their location.
Schwannoma of the medulla oblongata
Authors: Aryanpur John , Long Donlin M.
Published: May 2009

✓ A case of intraparenchymal schwannoma of the medulla oblongata is presented. The radiographic and pathological characteristics of this rare tumor are discussed, and the world literature regarding intracerebral intraparenchymal schwannomas is reviewed. The current etiological theories of these intra-axial nerve-sheath tumors are reviewed. The importance of early identification and differentiation of these potentially curable tumors from malignant glial tumors is emphasized.
Discrepancy between intraoperative SSEP's and postoperative function
Authors: Chatrian Gian-Emilio , Berger Mitchel S. , Wirch Adelina L.
Published: May 2009

✓ The authors report a case in which midline myelotomy for the removal of a C4–T4 ependymoma was immediately followed by abolition of short-latency somatosensory evoked potentials (SSEP's) in response to bilateral posterior tibial nerve (PTN) stimulation which proved irreversible intraoperatively. Subsequent intraoperative testing also revealed obliteration of median nerve (MN)-elicited responses. Postoperatively, joint and vibration sensations deteriorated in the lower extremities and there was unchanged very mild impairment of light touch, pinprick, and temperature sensibilities without significant loss of muscle strength. Nearly 5 months after surgery, despite recovery of postural and vibratory senses in the lower limbs and of SSEP's in response to MN stimulation, no SSEP's could be demonstrated on PTN stimulation. The possibility of “false positive” results (that is, intraoperative SSEP abolition without postoperative motor deficits) and of dissociations between SSEP's and deep sensation should be taken into consideration when interpreting SSEP's intraoperatively.
Intra-arterial bromodeoxyuridine radiosensitization and radiation in treatment of malignant astrocytomas
Authors: Greenberg Harry S. , Chandler William F. , Diaz Richard F. , Ensminger William D. , Junck Larry , Page Michaelyn A. , Gebarski Stephen S. , McKeever Paul , Hood Terry W. , Stetson Philip L. , Litchter Allen S. , Tankanow Roberta
Published: May 2009

✓ Bromodeoxyuridine (BUdR), a nonhypoxic radiosensitizing drug, is a halogenated pyrimidine analog that is incorporated into the deoxyribonucleic acid of dividing cells in a competitive process with thymidine; BUdR also sensitizes these cells to radiation therapy. Neurons and glial cells have a very low mitotic rate. They will not incorporate BUdR and will not be sensitized. Bromodeoxyuridine is best delivered intra-arterially because of its regional advantage, calculated to be between 6 and 16. An 8-week BUdR infusion is delivered before and during radiation therapy through a permanently implanted pump with a catheter placed retrograde into the external carotid artery. Eighteen patients with malignant glioma (15 grade IV, and three grade III) were entered into a Phase I dose-escalation protocol with BUdR dosages ranging from 400 to 600 mg/sq m/day. The maximum dose that can be tolerated appears to be 400 mg/sq m/day for 8 weeks. The 18 patients entered in this study have a median Kaplan-Meier estimated survival time (± standard error of the mean) of 22 ± 5 months with 11 patients still alive. Three patients are alive at 30, 29, and 21 months after diagnosis with no evidence of tumor on computerized tomography. There have been no vascular complications. Side effects in all patients have included anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, iritis, and nail ridging. Myelosuppression requiring dose reduction occurred in one patient. One patient had a Stevens-Johnson syndrome requiring termination of BUdR. It is concluded that intra-arterial BUdR may improve survival times in patients with malignant gliomas.
Removal of the anterior clinoid process for exposure of the proximal intracranial carotid artery
Authors: Nutik Stephen Lawrence
Published: May 2009

✓ The anatomy of the carotid artery at the level of the anterior clinoid process was studied in autopsy specimens and at surgery. Marking clips placed at surgery were used to correlate anatomical and angiographic findings. Removal of the anterior clinoid process permits visualization of approximately 6 mm more of the proximal internal carotid artery without entering the cavernous sinus. The exposure reaches just to the hairpin bend of the carotid siphon, but the bend is not seen. The curve in the carotid artery which is observed after anterior clinoid removal is distal to the hairpin turn and corresponds to a bend seen on the anteroposterior projection of the angiogram. Temporary occlusion of the carotid artery proximal to a paraclinoid aneurysm is possible after clinoid removal. Complications of the removal include trauma to the third nerve and cerebrospinal fluid rhinorrhea.