bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced platelet function in subarachnoid hemorrhage
Authors: Tsementzis Sotirios A. , Gill Jaswinder S. , Hitchcock Edward R. , Hartley Jennifer A. , Gill Surinder K. , Beevers D. Gareth
Published: May 2009

✓ The hypothesis that abnormalities of platelet function may relate to the occurrence or recurrence of subarachnoid hemorrhage (SAH) has been examined. Seventy patients with SAH and 65 control individuals were studied. The adenosine diphosphate (ADP) threshold for secondary platelet aggregation was significantly higher in the SAH group than in the controls. In tests using 4.0 µg/ml ADP, the percent platelet aggregation (at 2 minutes) and the maximum rate of platelet aggregation (over 20 seconds) were significantly lower in the SAH patients. There was no difference in total platelet count between the two groups. Platelet adhesiveness was lower in the SAH patients when compared to controls. Circulating microaggregates did not differ between the two groups. The results indicate that reduced platelet function does relate to SAH and may either contribute to aneurysmal rupture in cases of SAH or be a consequence of it.
Laser photochemotherapy of rhodamine-123 sensitized human glioma cells in vitro
Authors: Powers Stephen K. , Pribil Stefan , Gillespie G. Yancey , Watkins Pamela J.
Published: May 2009

✓ The photochemotherapeutic effect of the mitochondria-specific dye rhodamine-123 (Rh-123) on human glioma cells in culture was studied. Cultured U-251MG glioma cells were incubated for 30 minutes in 10 µg/ml of Rh-123 and then exposed to blue-green light between 488 and 514.5 nm using a continuous-wave argon laser. Cells that were treated with Rh-123 and the argon laser at power densities less than 200 mW/sq cm demonstrated increasing tumor-cell killing with increasing time of exposure to laser light. Tumor-cell killing achieved with power densities of light less than 200 mW/sq cm was shown to be due solely to a photochemical effect and not to a direct (thermal) effect of the laser. The photochemical effect was dependent upon the intracellular concentration of Rh-123 and the length of light exposure, and not the intensity of light. The selective retention of Rh-123 by glioma cells and its exclusion from normal cells in conjunction with its photoactivated cytotoxicity suggest that Rh-123 may be a useful photosensitizing drug for the treatment of malignant gliomas in situ.
Temporalis myofascial repair of traumatic defects of the anterior fossa
Authors: Gillespie Ritchie P. , Shagets Frank W. , de los Reyes Raul A.
Published: May 2009

✓ Bilateral temporalis myofascial flaps in continuity with frontal periosteum can be used in repairing extensive dural and bone defects of the anterior cranial fossa floor. The technique of preserving and using this flap is described and offers an alternative to the use of frontal pericranial tissue for repair of anterior dural defects.
The incidence of epilepsy after ventricular shunting procedures
Authors: Dan Noel G. , Wade Megan J.
Published: May 2009

✓ One hundred eighty of 207 consecutive patients with ventricular shunts were studied to determine the incidence of post-shunt epilepsy. Of these 17 (9.4%) developed seizures. The incidence fell from 15.2% in children younger than 1 year to 6.9% in patients over 50 years of age, but age was not statistically significant. Of patients with a parietal ventricular catheterization site only 6.6% had convulsions, in contrast to 54.5% of those with a frontal locus. The incidence of seizures rose with multiple ventricular catheter revisions, but was unrelated to bilaterality of shunting. The risk of seizures fell from 5% in the 1st year after shunting to 1.1% after the 3rd year.
Surgical management of craniopharyngiomas
Authors: Baskin David S. , Wilson Charles B.
Published: May 2009

✓ A series of 74 patients with craniopharyngiomas were treated during a 15-year period. Of the 74 patients, 40 were males and 34 were females, with a mean age of 27 years (range 3 to 65 years). Twenty-eight patients (38%) were less than 18 years of age. Remission was defined as clinical improvement with stable ophthalmological and neurological status, radiological evidence of a decrease in tumor size, and either a continued decrease or a stable tumor size on follow-up radiological evaluations. A fair result was considered remission with new neurological deficits related to surgical intervention. All other results were considered a failure. The mean follow-up period in this study was 4 years, with 100% of the patients monitored.

In children, the most common presentation was that of growth failure (93%). In adults, sexual dysfunction was the most common presentation, with 88% of males presenting with impotence or marked decrease in sexual drive, and 82% of females presenting with primary or secondary amenorrhea, often associated with galactorrhea. Considering the pediatric and adult populations together, the most common presenting symptom was visual dysfunction, with 71% of patients presenting in this manner. Fifty percent of patients presented with severe headache. The most frequent preoperative finding was a visual field defect, with 72% of patients so affected; 42% of patients had preoperative hypothyroidism and 24% had hypoadrenalism. Diabetes insipidus was present preoperatively in 23%. Hydrocephalus was uncommon, being present in only 15%.

A subfrontal craniotomy was used in 47% of patients, a transsphenoidal approach in 39%, a subtemporal approach in 11%, a transcallosal approach in 5%, and a suboccipital craniectomy in 2%. Multiple procedures were required in 15% of patients in order to provide significant relief of compressive symptomatology. The results of therapy indicate that total tumor removal was deemed to have been achieved in only seven patients, six of whom have had no recurrence. However, 91% of patients are in remission, one had a fair result, and two died as a direct result of surgical intervention. One patient died from uncontrolled disease, and three patients died from unrelated causes. The results of this study indicate that radical subtotal removal followed by radiotherapy is an acceptable treatment for craniopharyngioma.
Percutaneous retrogasserian glycerol rhizotomy for trigeminal neuralgia
Authors: Arias Manuel J.
Published: May 2009

✓ A prospective study of percutaneous retrogasserian glycerol rhizotomy (PRGR) with and without metrizamide trigeminal cisternography is reported in the treatment of the trigeminal neuralgia. A series of 100patients with typical trigeminal neuralgia were allocated randomly to two treatment groups: Group I patients received PRGR with trigeminal cisternography (50 cases) and Group II patients received PRGR without trigeminal cisternography (50 cases). The results indicate that PRGR without trigeminal cisternography is a valid alternative to the original technique. Factors that assured the accurate performance of the modified technique proposed in this study were: 1) spontaneous cerebrospinal fluid drainage; 2) radiologically confirmed placement of the thin spinal needle at the clival edge into the trigeminal impression of the petrous apex and in the center of the foramen ovale; 3) a positive response to the glycerol test; 4) clinical control of the final glycerol injection; and 5) an alert and cooperating patient throughout the entire procedure.
Therapeutic efficacy of a somatostatin analogue (SMS 201–995) in active acromegaly
Authors: Tolis George , Yotis Angelos , del Pozo Emilio , Pitoulis Spyros
Published: May 2009

✓ Twelve patients with active acromegaly, six of whom had not responded to previous combined surgery, radiotherapy, and bromocriptine administration, were treated with an octapeptide long-acting somatostatin analogue, SMS 201–995, given subcutaneously for up to 1 year. Growth hormone (GH) levels decreased by 50% to 90% after a single 25-µg SMS 201–995 injection in all patients, including two who were resistant to bromocriptine therapy. After GH values reached a nadir, they returned to preinjection values over a 12-hour period and no rebound was seen. Assessment of the GH-lowering effect of the drug at weekly intervals for the first 6 weeks and monthly thereafter disclosed no tachyphylaxis. Gradual increase of the dose from 50 to 150 µg daily led to a significant increase in clinical improvement. Shrinkage of the size of the pituitary tumor was documented in three of nine evaluated cases. Abdominal cramps of a transient nature not associated with diarrhea were noted in two patients but there were no other side effects. Hematological and biochemical blood and urine tests, including serum thyroxine and cortisol levels, did not reveal any abnormality during chronic treatment. This study demonstrates the safety and efficacy of SMS 201–995 in the short-term treatment of acromegaly.
The effects of HA compound calcium antagonists on delayed cerebral vasospasm in dogs
Authors: Takayasu Masakazu , Suzuki Yoshio , Shibuya Masato , Asano Toshio , Kanamori Masahiko , Okada Tomohisa , Kageyama Naoki , Hidaka Hiroyoshi
Published: May 2009

✓ The authors have examined the effects of the HA compounds HA1004(N-(2-guanidinoethyl)-5-isoquino-linesulfonamide) and HA1077(l-(5-isoquinolinesulfonyl)homopiperazine), which are intracellular calcium antagonists, on delayed cerebral vasospasm from subarachnoid hemorrhage (SAH). The modes of action of these compounds were compared with those of the more commonly used calcium entry blockers. Calcium ionophore A23187 (4.8 × 10−6 M)-induced contraction of a canine basilar artery strip was completely antagonized by the HA compounds (10−5 M) but not by the entry-blocking calcium antagonists nicardipine, diltiazem, and verapamil (10−5 M), suggesting that the HA compounds act differently. Delayed cerebral vasospasm was induced by a “two-hemorrhage” canine model. The magnitude of the vasospasm and the effects of the HA compounds were determined angiographically. On SAH Day 7, a significant vasospasm was observed in every dog. The diameter of the basilar artery had diminished to 59% ± 2% (mean ± standard error) of the control value obtained before SAH (on Day 1). The intravenous administration of HA1004 caused a mild dilation of the basilar artery of 10% and 11% at doses of 3 and 10 mg/kg, respectively; however, HA1077 produced a more marked dilation of 19% and 27%, respectively, at the same doses. Both of these drugs lowered mean arterial blood pressure to about 80% and 50% at doses of 3 and 10 mg/kg, respectively. Intracisternal administration of the HA compounds (6 mg) completely reversed cerebral vasospasm without much effect on the blood pressure. The intracellular calcium antagonists of the HA compound group appear to be promising agents for the treatment of intractable cerebral vasospasm.
Alveolar hydatid disease of the brain
Authors: Aydin Yunus , Barlas Orhan , Yolaş Coşkun , Aydin İsmail Hakki , Ceviz Adnan , Aladağ Arif , Ören Durkaya , Akdemir Dursun
Published: May 2009

✓ Four cases of alveolar hydatid disease of the brain encountered within 27 months in eastern Turkey are reported. All of the patients were male farmers who presented with signs of cerebral tumor. Two of the patients were shown to harbor hepatic lesions and one of them had pulmonary metastases. The cerebral lesions were removed in toto and neurological recovery was obtained in all four patients. A review of the literature revealed only five previously reported cases treated surgically. It is concluded that cerebral Echinococcus multilocularis lesions are amenable to surgery, and that their removal provides useful prolongation of life despite the presence of hepatic or pulmonary disease.
Stereotaxic biopsy of intrinsic lesions of the brain stem
Authors: Hood Terry W. , Gebarski Stephen S. , McKeever Paul E. , Venes Joan L.
Published: May 2009

✓ Despite improved brain-stem imaging by magnetic resonance and high-resolution x-ray computerized tomography, definitive diagnosis and therapy of intrinsic lesions of the brain stem require histological verification. A stereotaxic approach to brain-stem lesions provides a high yield of positive histological diagnosis with a low incidence of morbidity. A series of 14 stereotaxic procedures performed on 12 patients with intrinsic lesions of the mesencephalon, pons, and medulla is reviewed. A detailed description of the transfrontal approach used by the authors is presented. Definitive pathological diagnosis was obtained in all patients. There was no operative mortality and only one case of permanent neurological deficit. The significance of accurate histological diagnosis in the therapy of brain-stem lesions is discussed.
Intracerebral ganglioglioma
Authors: Demierre Bertrand , Stichnoth Falko A. , Hori Akira , Spoerri Otto
Published: May 2009

✓ Ganglioglioma in the temporal lobe was encountered in 0.6% of a series of 998 patients undergoing biopsy for intracranial tumors. It was more frequent in young adults and children. Seizures were the main symptom and had been present over a long period of time in some patients. Clinical examination also revealed intracranial pressure, focal signs, and behavioral problems, but these symptoms were not always evident. Electroencephalography was not specific. Calcifications were visible on computerized tomography (CT) in five cases. The cystic and well-circumscribed aspects of these tumors were apparent on CT scans; these features were confirmed at operation and on magnetic resonance imaging (MRI), when it was also found that the tumors were partially solid. Therefore, MRI seems to be a useful diagnostic method, particularly when a cystic tumor is revealed on CT, and is also valuable for postoperative monitoring. Surgical treatment for ganglioglioma is recommended, with total extirpation if possible.
Orthostatic hypotension from a cerebellar gangliocytoma (Lhermitte-Duclos disease)
Authors: Ruchoux Marie-Magdeleine , Gray Francoise , Gherardi Romain , Schaeffer Annette , Comoy Jean , Poirier Jacques
Published: May 2009

✓ A 49-year-old woman presented with orthostatic hypotension. Vertebral angiography and ventriculography revealed a tumor of the left cerebellar hemisphere. Ventriculoperitoneal shunting was followed by complete disappearance of the orthostatic hypotension. The tumor was subsequently removed and microscopic study showed Lhermitte-Duclos disease. Orthostatic hypotension has been rarely reported in association with tumors of the posterior fossa except for those tumors destroying the medullary centers and interrupting the baroreceptor reflex arc. This case is of interest because the tumor was restricted to the cerebellum. The authors have found no previous case in which orthostatic hypotension was a presenting symptom of Lhermitte-Duclos disease.
Double-headed stereotaxic carrier apparatus for insertion of depth electrodes
Authors: Olivier André
Published: May 2009

✓ A carrier device has been developed for use with a stereotaxic apparatus. It can be attached to the OBT frame or to any Leksell-type frame. With this carrier, intracranial insertion of commercially available depth electrodes with built-in connectors is possible. By using two different heads mounted on a single carrier, the surgeon can perform a transcutaneous twist-drill trephination and attach the screws through a chuck, adjust the device in the horizontal plane, and then insert and anchor the electrodes by using a small platform with a hinged roof.
The innervation and function of the lower urinary tract
Authors: McGuire Edward J.
Published: May 2009

✓ Vesical and urethral function are closely controlled by neural activity, both reflex and volitional. Relatively subtle abnormalities have serious consequences. Understanding of the natural history of neurogenic vesical dysfunction has improved over the past few years and is summarized in this review article.
Anatomical relationships of the pia mater to cerebral blood vessels in man
Authors: Hutchings Margaret , Weller Roy O.
Published: May 2009

✓ Using scanning and transmission electron microscopy and light microscopy, the authors studied the human pia mater and its relationship to the entry of blood vessels into the normal cerebral cortex. The purpose of this investigation was to examine the long-established concept that the subarachnoid space communicates directly with the perivascular spaces of the cerebral cortex. Brains obtained post mortem from subjects with recent subarachnoid hemorrhage (SAH) and purulent leptomeningitis were studied by light microscopy to determine the permeability of the pia mater to red blood cells and inflammatory cells. Scanning electron microscopy showed that the normal pia mater is a flat sheet of cells that is reflected from the surface of the brain to form the outer coating of the meningeal vessels in the subarachnoid space. Transmission electron microscopy confirmed that the cells of the pia mater are joined by junctional complexes and form a continuous sheet that separates the subarachnoid space on one side from the subpial and perivascular spaces on the other. Thus, neither the pia mater nor the subarachnoid space extends into the brain beside blood vessels as they enter the cerebral cortex. The perivascular spaces were, in fact, found to be confluent with the subpial space and not with the subarachnoid space. In cases of recent SAH, red blood cells did not enter the perivascular spaces from the subarachnoid space; neither did India ink injected post mortem into the subarachnoid space pass into the perivascular spaces. The results of these crude tracer studies suggest that the pia mater is an effective barrier to the passage of particulate matter. Histological examination of brains of patients who had died with purulent leptomeningitis showed that inflammatory cells were present in the cortical perivascular spaces and in the contiguous subpial spaces. The presence of a large number of inflammatory cells in the subarachnoid space suggests that inflammatory cells readily penetrate the pia mater that separates the perivascular spaces from the subarachnoid space. The permeability of the pia mater to small molecular weight substances is briefly discussed.
Effects of nimodipine on in vitro contractility of cerebral arteries of dog, monkey, and man
Authors: Nosko Michael , Krueger Christel A. , Weir Bryce K. A. , Cook David A.
Published: May 2009

✓ Cerebrovascular spasm in the cynomolgus monkey does not appear to be modified by nimodipine. It is possible that cerebral arteries from this species are unusually resistant to the action of calcium antagonists. To test this hypothesis, parallel studies on the in vitro response of cerebral arteries from monkey, dog, and man have been carried out. Rings of basilar or middle cerebral artery were tested with potassium chloride, noradrenaline, 5-hydroxytryptamine, prostaglandin F2α, and hemoglobin. The responses were then reexamined in the presence of various concentrations of nimodipine. There is a significant variation among species in sensitivity to nimodipine, the vessels from the monkey being more resistant to nimodipine than those from other species. There is, as expected, a considerable difference in the ability of nimodipine to block the different agonists. Responses to potassium chloride are blocked by low concentrations of nimodipine in all species, whereas noradrenaline and 5-hydroxytryptamine are more resistant. It is noteworthy that, in all species tested, hemoglobin and prostaglandin F2α were antagonized poorly even by higher concentrations of nimodipine. if these agonists play a major role in the development of vasospasm and subsequent delayed ischemia, it may be that the calcium antagonists exert a beneficial effect by some mechanism other than dilation of spastic arteries.
The long-latency component of cerebral evoked potentials in anesthetized cats
Authors: Lee Kyu Ho , Kim Jun , Chung Jin Mo
Published: May 2009

✓ A late component of the cortical evoked potential elicited by somatosensory afferent input was studied in cats anesthetized with α-chloralose. Cortical evoked potentials were recorded from the somatosensory-motor cortex during stimulation of the sural nerve with graded intensities. The stimulus intensity was adjusted to activate Aαβ fibers only, then both Aαβ and Aδ fibers, and both A and C fibers, as judged by afferent volleys monitored from the sural nerve proximal to the stimulating site. In addition to early components reported previously, a very late component was identified at a latency of 400 to 600 msec following stimulation of the sural nerve with intensities above threshold for Aδ fibers. A further increase in stimulation intensity to include activation of C fibers did not reveal any more components. This late component was depressed by a systemic intravenous injection of morphine (2 mg/kg), and intravenous naloxone (0.1 mg/kg) reversed the effect of morphine. The late component of the evoked potential could also be recorded from subcortical tissue after decortication of the sensorimotor cortex.

From these results, it appears that a very late component of the cortical evoked potential can be recorded from cats anesthetized with α-chloralose. The late component is evoked by activation of peripheral Aδ fibers. Furthermore, its morphine sensitivity suggests that this component may be elicited by nociceptive afferent fibers. If further investigations prove this, the late component, which is analogous to human long-latency potentials, could be used in an experimental model for pain research.
Experimental model for induction of cerebral aneurysms in rats
Authors: Alvarez Fernando , Roda José M.
Published: May 2009

✓ Two groups of rats with induced arterial hypertension were studied. One group underwent section of the left common carotid artery with an end-to-side anastomosis of the proximal segment to the right common carotid artery. The second group was subjected to ligation of the left common carotid artery. The number of aneurysms caused by the procedure in the first group was higher, the difference being statistically significant (p < 0.05, chi-square).
Infinite needs: finite resources
Authors: Lamm Richard D.
Published: May 2009

✓ In this 199th year of constitutional government in the United States a careful evaluation of all our basic institutions is required if this country is to remain a great nation. The delivery of health care, a basic institution, must be included in the determination of how finite resources can be most effectively and efficiently used for what appears to be almost infinite needs.
Saphenous vein bypass grafts for giant aneurysms and intracranial occlusive disease
Authors: Sundt Thoralf M. , Piepgras David G. , Marsh W. Richard , Fode Nicolee C.
Published: May 2009

✓ The authors report their experience with the use of saphenous vein bypass grafts for treating advanced occlusive disease in the posterior circulation (77 patients, all of whom had failed medical management and showed severe ischemic symptoms), deteriorating patients with giant aneurysms of the posterior circulation (nine patients), progressive ischemia in the anterior circulation (26 patients, none of whom had a normal examination), and giant aneurysms in the anterior circulation (20 patients, all of whom presented with mass effect or subarachnoid hemorrhage). Graft patency in the first 65 cases treated was 74%. However, after significant technical changes of vein-graft preparation and construction of the proximal anastomosis, patency in the following 67 cases was 94%. Excellent or good results (including relief of deficits existing prior to surgery) were achieved in 71% of patients with advanced occlusive disease in the posterior circulation, 44% of those with giant aneurysms of the posterior circulation, 58% of those with ischemia of the anterior circulation, and 80% of those with giant aneurysms of the anterior circulation. Mean graft blood flow at surgery in the series was 100 ml/min for posterior circulation grafts and 110 ml/min for anterior circulation grafts. Experience to date indicates that this is a useful operation, and is particularly applicable to patients who are neurologically unstable from advanced intracranial occlusive disease in the posterior circulation or with giant aneurysms in the anterior circulation. The risk of hyperperfusion breakthrough with intracerebral hematoma restricts the technique in patients with progressing ischemic symptoms in the anterior circulation, and the intolerance of patients with fusiform aneurysms in the posterior circulation to the iatrogenic vertebrobasilar occlusion limits the applicability of this approach to otherwise inoperable lesions in that system.
Internal carotid artery stump angioplasty for the treatment of cerebrovascular occlusive disease
Authors: Benzel Edward C. , Sittig Kevin M. , Mirfakhraee Mansour
Published: May 2009

✓ Nineteen patients underwent a total of 21 stump angioplasty procedures for an occluded internal carotid artery. Indications for surgery included the preparation of the donor vessel for a subsequent extracranial-intracranial bypass procedure, the occurrence of emboli to the intracranial vasculature from the external carotid artery circulation, and the association with symptomatic occlusive disease of the external carotid artery accompanying occlusion of the ipsilateral internal carotid artery.

The technique utilized and the results obtained in these 19 patients are presented. In select patients, the removal of an occluded internal carotid artery stump via a stump angioplasty is beneficial in preventing the catastrophic sequela of embolic cerebrovascular disease.
A proposed grading system for arteriovenous malformations
Authors: Spetzler Robert F. , Martin Neil A.
Published: May 2009

✓ An important factor in making a recommendation for treatment of a patient with arteriovenous malformation (AVM) is to estimate the risk of surgery for that patient. A simple, broadly applicable grading system that is designed to predict the risk of morbidity and mortality attending the operative treatment of specific AVM's is proposed. The lesion is graded on the basis of size, pattern of venous drainage, and neurological eloquence of adjacent brain. All AVM's fall into one of six grades. Grade I malformations are small, superficial, and located in non-eloquent cortex; Grade V lesions are large, deep, and situated in neurologically critical areas; and Grade VI lesions are essentially inoperable AVM's.

Retrospective application of this grading scheme to a series of surgically excised AVM's has demonstrated its correlation with the incidence of postoperative neurological complications. The application of a standardized grading scheme will enable a comparison of results between various clinical series and between different treatment techniques, and will assist in the process of management decision-making.
A proposed scheme for grading intracranial arteriovenous malformations
Authors: Shi Yu-quan , Chen Xian-cheng
Published: May 2009

✓ A four-grade classification scheme for intracranial arteriovenous malformations (AVM's) is proposed. Grading is based on 1) the size of the AVM; 2) its location and depth; 3) its arterial supply; and 4) its venous drainage. Each of these aspects is divided into four grades with respect to the difficulty it poses for surgical excision. A description of the grading system and its application is given. This grading scale has been correlated with the operative morbidity and mortality in 100 cases of excised intracranial AVM's. The results show that the higher the grade of AVM, the greater the risk of surgical morbidity and mortality. This grading scale is simple and easy to apply. It can guide neurosurgeons in selecting AVM patients suitable for operation, in determining the best type of operation to perform, and in predicting operative difficulties as well as postoperative results.
Hypothalamic dysfunction following whole-brain irradiation
Authors: Mechanick Jeffrey I. , Hochberg Fred H. , LaRocque Alan
Published: May 2009

✓ The authors describe 15 cases with evidence of hypothalamic dysfunction 2 to 9 years following megavoltage whole-brain x-irradiation for primary glial neoplasm. The patients received 4000 to 5000 rads in 180- to 200-rad fractions. Dysfunction occurred in the absence of computerized tomography-delineated radiation necrosis or hypothalamic invasion by tumor, and antedated the onset of dementia. Fourteen patients displayed symptoms reflecting disturbances of personality, libido, thirst, appetite, or sleep. Hyperprolactinemia (with prolactin levels up to 70 ng/ml) was present in all of the nine patients so tested. Of seven patients tested with thyrotropin-releasing hormone, one demonstrated an abnormal pituitary gland response consistent with a hypothalamic disorder. Seven patients developed cognitive abnormalities. Computerized tomography scans performed a median of 4 years after tumor diagnosis revealed no hypothalamic tumor or diminished density of the hypothalamus. Cortical atrophy was present in 50% of cases and third ventricular dilatation in 58%. Hypothalamic dysfunction, heralded by endocrine, behavioral, and cognitive impairment, represents a common, subtle form of radiation damage.
Development of experimental meningeal gliomatosis models in rats
Authors: Yoshida Tatsuo , Shimizu Keiji , Ushio Yukitaka , Hayakawa Toru , Arita Norio , Mogami Heitaro
Published: May 2009

✓ Experimental models of meningeal gliomatosis (MG) have been produced by intracisternal inoculation of rat C6 and 9L glioma cells into Wistar and Fischer 344 rats, respectively. Tumor growth was steady and rapid in both MG models when more than 106 tumor cells were implanted. The median survival time of the rats inoculated with tumor cells was inversely related to the number of the cells inoculated. The clinicopathological features observed in both MG models were similar to those seen in diffuse leptomeningeal involvement of gliomas in humans. The models may be useful for investigating the pathophysiology of MG and for the determination of the efficacy of chemotherapeutic agents in brain-tumor chemotherapy.
Duration versus degree of hypotension as critical conditions of brain infarction in the albino rat
Authors: Laas Rudolf , Jahn Bernd , Kessler Kay
Published: May 2009

✓ In 41 anesthetized, spontaneously breathing male adult albino rats, cerebral hypotension of precisely defined duration and magnitude was induced by means of controlled arterial hemorrhage. One common carotid artery was occluded throughout the hypotensive period, and the target pressure was monitored in the ipsilateral internal carotid artery. Regional brain infarcts developed in all 16 animals with a target pressure of 14 mm Hg maintained for 90 minutes and in all five animals with a target pressure of 12 mm Hg maintained for 70 minutes. However, the brains of all 10 rats with a target pressure of 17 mm Hg maintained for 80 minutes remained intact. In two further groups of five animals each with target pressures of 15 mm Hg for 80 minutes and 16 mm Hg for 90 minutes the incidence of infarct was about 30%. There were no marked differences between the five groups of rats in body weight, body temperature, heart rate, respiratory rate, PaO2, PaCO2, arterial pH, or hematocrit.

The data suggest that, in the rat, the clear-cut threshold for the induction of brain infarcts is a function of the severity and duration of arterial hypotension. Evidence is presented indicating that this function is distinctly species-dependent, due to species differences in the dilatory capacity of the arteries supplying the brain rather than species differences in brain vulnerability.
Cerebral perivascular nerves in subarachnoid hemorrhage
Authors: Hara Hideaki , Nosko Michael , Weir Bryce
Published: May 2009

✓ The authors have studied the changes induced by subarachnoid hemorrhage (SAH) in the density and distribution of cerebral perivascular nerves in monkeys and rats. The SAH was induced in monkeys by placement of an autologous blood clot after opening the basal cisterns over the arteries of the circle of Willis on one side. In the rat study, SAH was induced by injection of autologous arterial blood into the cisterna magna. The nerves examined were adrenergic nerves, acetylcholinesterase (AChE)-containing nerves, vasoactive intestinal polypeptide (VIP)-like immunoreactive nerves, and substance P-like immunoreactive nerves. In the monkey study, all animals underwent baseline cerebral angiography, then had repeat angiography just before sacrifice on Day 2, 7, 28, or 70 after SAH. Two sham-operated monkeys underwent the surgical procedure without clot placement and were sacrificed on postoperative Day 7, after repeat angiography. Clot placement in monkeys reduced staining of all middle cerebral artery (MCA) perivascular nerves for between 2 and 28 days post-SAH. The number of stained nerve fibers of MCA's on the non-operated side was slightly reduced on Days 2 and 7 after SAH. Sham-operated monkeys showed a mild reduction of staining in all nerves, but only on the operated side. Cerebral vasospasm was observed on all angiograms taken on Days 2 and 7 following SAH. No vasospasm was found in normal or sham-operated monkeys. The disappearance of nerve staining without associated vasospasm was found on the operated side of the sham-operated monkeys and on the clot side of the animal sacrificed on Day 28 after SAH. Rats sacrificed on Days 2 and 7 post-SAH showed reduction in adrenergic and VIP-like immunoreactive staining around basilar arteries, while nerves containing AChE were not affected. Saline-injected rats exhibited no change in the appearance of perivascular innervation. These results suggest that SAH as well as surgical manipulation of the vessel wall caused a reduction of the studied substances in cerebral perivascular nerves. This reduction in immunoreactive staining of perivascular nerves did not correlate with the development of angiographic vasospasm after SAH.
A frameless stereotaxic integration of computerized tomographic imaging and the operating microscope
Authors: Roberts David W. , Strohbehn John W. , Hatch John F. , Murray William , Kettenberger Hans
Published: May 2009

✓ A computer-based system has been developed for the integration and display of computerized tomography (CT) image data in the operating microscope in the correct perspective without requiring a stereotaxic frame. Spatial registration of the CT image data is accomplished by determination of the position of the operating microscope as its focal point is brought to each of three CT-imaged fiducial markers on the scalp. Monitoring of subsequent microscope positions allows appropriate reformatting of CT data into a common coordinate system. The position of the freely moveable microscope is determined by a non-imaging ultrasonic range-finder consisting of three spark gaps attached to the microscope and three microphones on a rigid support in the operating room. Measurement of the acoustic impulse transit times from the spark gaps to the microphones enables calculation of those distances and unique determination of the microscope position. The CT data are reformatted into a plane and orientation corresponding to the microscope's focal plane or to a deeper parallel plane if required. This reformatted information is then projected into the optics of the operating microscope using a miniature cathode ray tube and a beam splitter. The operating surgeon sees the CT information (such as a tumor boundary) superimposed upon the operating field in proper position, orientation, and scale.
Compression-expansion forceps for intracranial dissection and retraction
Authors: Davidson Robin I. , Rodgers Cyril
Published: May 2009

✓ A hand-held double-bladed retractor has been designed in the form of a cross-action bayonette. It acts to retract both lips of an incision simultaneously. The device can be adapted for other uses.
Cerebral protection
Authors: Hoff Julian T.
Published: May 2009

✓ Cerebral protection from an ischemic/hypoxic insult implies that tissue injury can be controlled or even prevented by certain therapeutic maneuvers. For example, physiological thresholds may be altered so that tissue vulnerability to the insult is reduced, or the intensity of an insult may be blunted by enhancing brain homeostasis. Such a therapeutic maneuver is carotid endarterectomy to improve blood flow in the disordered hemisphere. Alternatively, drugs with protective properties can be used before or even after the insult to “stabilize” injured tissue and prevent the harmful secondary effects that often follow.

Various past and present approaches to cerebral protection employing physiological, pharmacological, and surgical intervention are reviewed. The mechanisms by which each allegedly protects the brain from ischemia and hypoxia are discussed briefly. Promising, but not always successful, approaches used in the past have pointed the way for new and more rational therapies. Truly effective protection of the brain from ischemia and hypoxia depends directly upon our capability to explore basic mechanisms of injury and our willingness to measure accurately and objectively the outcome of newly developed protective measures.
Intracranial malignant lymphoma
Authors: Jiddane Mohamed , Nicoli François , Diaz Pédro , Bergvall Ulf , Vincentelli François , Hassoun Jacques , Salamon Georges
Published: May 2009

✓ Although primary malignant lymphoma is a rare entity in the gamut of intracranial tumors, it is more frequently seen than the secondary intracranial spread of a primary extracranial lymphoma. In general, the occurrence of lymphomas seems to be provoked by immunosuppression, as with medication (predominantly after transplantation) or with immunodepressive disease such as acquired immunodeficiency syndrome (AIDS). The usual age of onset of this disease is 55 to 65 years; and the male:female patient distribution is roughly 2:1.

Characteristically, computerized tomography (CT) scans of lymphomas show a mass which is often large with regular contours, moderate mass effect, and hyper- or isodensity with marked and often homogeneous enhancement. In the series of 30 patients reported, the locations of lesions, in order of decreasing frequency, were the frontocallosal and temporal regions, the basal ganglia, and the cerebellum. Multiple lesions were present in 15% of these cases (20% to 40% in the literature). The following features should raise the suspicion of intracranial lymphoma: mirror lesions of the basal ganglia, bilateral subependymal infiltration, and leptomeningeal involvement contiguous with an intracerebral mass.

According to the literature, the angiographic finding typical of lymphoma is an avascular tumor. A blush or vascular encasement of the mass seems to be rare, and the present series was in accordance with other reports in this respect. Differential diagnostic consideration should include meningioma, glioblastoma, metastatic disease, and focal infectious lesions such as toxoplasmosis or multifocal progressive leukoencephalitis, particularly in immunodepressed subjects. Diagnosing lymphoma from CT scans offers the alternative of substituting stereotaxic biopsy and neuropathological diagnosis for the more aggressive open surgical approach, since radiation therapy and possibly chemotherapy usually prove to be the treatment of choice.
Relationship of acute CBF and ICP findings to neuropsychological outcome in severe head injury
Authors: Uzzell Barbara P. , Obrist Walter D. , Dolinskas Carol A. , Langfitt Thomas W.
Published: May 2009

✓ Neuropsychological outcome within 1 year after severe head injury was examined in 42 conscious survivors and correlated with acute measurements of cerebral blood flow (CBF) and intracranial pressure (ICP). During acute coma, CBF was elevated in 23 patients, indicating hyperemia, and was reduced in the remaining 19 cases. Intracranial hypertension (ICP 20 mm Hg or greater) was present acutely in 15 patients and absent in 27. Occurrences of hyperemia and intracranial hypertension were significantly related. During chronic recovery, neuropsychological dysfunction was found in all cases. However, patients with hyperemia revealed greater impairment of overall intellectual and memory functions than did those with reduced flow, while patients with intracranial hypertension showed greater memory deficit than did those without ICP elevations. The results suggest that early pathophysiological events can influence subsequent neuropsychological outcome, and that chronic recovery is not homogeneous in young severely head-injured adults.
Intrastriatal adrenal medulla grafts in rats
Authors: Freed William J. , Cannon-Spoor H. Eleanor , Krauthamer Eleanor
Published: May 2009

✓ Rats with rotational behavior consequent to unilateral lesions of the substantia nigra have been proposed for an experimental model of Parkinson's disease. Adrenal medulla or embryonic substantia nigra grafts in the lateral ventricle of these animals reduce this rotational behavior. For application to primate and human subjects, it may be necessary to implant tissue directly into the parenchyma of the corpus striatum rather than into the ventricle in order to achieve a sufficient distribution of the grafted tissues and increase the efficacy of the grafts. In the present study, the properties of intraparenchymal adrenal medulla grafts were investigated. Grafts were obtained from both young (4 to 5 weeks old) and aging (22 to 24 months old) donor rats. Much of the implanted tissue did not survive, although 200 chromaffin cells per recipient rat were found to have survived for at least 6 months. All of the surviving cells developed process-like cytoplasmic extensions, although these processes did not appear to have reinnervated host brain tissue. Grafts from both young and aging donor rats prevented a slight deterioration in the performance of a sensory neglect test that was observed in a control group that received grafts of sciatic nerve. There was also a tendency that did not reach statistical significance for grafts from young (but not from aging) donors to decrease apomorphine-induced rotational behavior. It is concluded that, although the corpus striatum does not appear to provide a particularly favorable environment for the implantation of adrenal medulla grafts, striatal implants of adrenal medulla might become a promising procedure if a means of improving the survival of these tissues could be developed.
Effect of dexamethasone, indomethacin, ibuprofen, and probenecid on carrageenan-induced brain inflammation
Authors: Gamache Daniel A. , Ellis Earl F.
Published: May 2009

✓ A model of brain inflammation has recently been developed in mice using intraventricular injection of carrageenan (CAR). This model is characterized by increased brain water and vascular permeability, by neutrophil extravasation, and by evidence of increased pro-inflammatory arachidonic acid metabolites. The purpose of the current experiments was to determine the mechanism(s) by which CAR induces brain inflammation and to determine the utility of the CAR model in testing systemically administered therapeutic agents for their capacity to inhibit brain inflammation. Dexamethasone inhibited the increased brain water but not the increased vascular permeability produced by CAR. Indomethacin, an inhibitor of prostaglandin formation, suppressed peripheral inflammation produced by local injection of CAR but not brain inflammation produced by intraventricular CAR injection. Subsequent studies with carbon-14-labeled indomethacin showed that indomethacin penetrates peripheral tissues but is excluded from normal brain or brains inflamed by injection of CAR. Ibuprofen, another prostaglandin synthesis inhibitor, also had no effect on brain inflammation. Probenecid, an organic acid transport inhibitor, completely inhibited CAR-induced brain inflammation and also slowed brain elimination of intraventricularly administered prostaglandins.

These experiments suggest, but do not conclusively prove, that increased prostaglandin formation contributes to brain inflammation. Also, the results with indomethacin and CAR-induced brain inflammation indicate that CAR-induced inflammation may be a useful model for screening for the ability of anti-inflammatory agents to cross the blood-brain barrier and exert their effect on brain inflammation.
A cavernous sinus cavernous hemangioma
Authors: Rosenblum Bruce , Rothman Allen S. , Lanzieri Charles , Song Sun
Published: May 2009

✓ The case of a Turner's syndrome patient with an intracavernous cavernous hemangioma is presented. The rarity of this lesion is stressed, as is surgical removal without postoperative deficit, the role of estrogens in the pathogenesis, and the clinical and radiological findings.
Early cerebral angiography after aneurysm rupture
Authors: Amagasa Masaharu , Yoshimoto Takashi , Mizoi Kazuo , Suzuki Jiro
Published: May 2009

✓ Although many patients with aneurysm rupture have undergone re-rupture during angiography, this event seldom occurs in the early period after the original hemorrhage. The authors review 197 cases of ruptured cerebral aneurysms that had received cerebral angiography within 1 week of rupture. With the exception of one case of re-rupture during angiography, no complications were noted in any of the patients. The criteria used for early cerebral angiography after aneurysm rupture are described.
Computerized tomography in the prognosis of malignant cerebral gliomas
Authors: Murovic Judith , Turowski Krzysztof , Wilson Charles B. , Hoshino Takao , Levin Victor
Published: May 2009

✓ Ninety-seven patients with supratentorial malignant gliomas who received postoperative radiation therapy and chemotherapy at the University of California, San Francisco, from 1977 through 1984 showed improvement in their follow-up computerized tomography (CT) scans. Twenty-one of these 97 “CT responders” were designated “complete responders” because on serial CT scans they had complete disappearance of the tumor mass and contrast enhancement, which had been present postoperatively. In the remaining 76 patients, CT scans showed reduction in the size, but not disappearance, of the lesions, and these were designated “partial responders.” Fifty-eight partial responders had glioblastoma multiforme (GM); their median survival time was 72 weeks. The median survival time for the 11 complete responders with GM has not yet been achieved, but survival at the 53rd percentile is 172 weeks. Among patients with highly anaplastic astrocytoma, the median survival time was 211 weeks for the 10 complete responders and 125 weeks for the 18 partial responders. Eleven of the 21 complete responders are alive at a median postoperative follow-up time of 163 weeks (range 114 to 470 weeks). Eighteen of these patients had subtotal resection of tumor; three patients had gross total tumor resections, but postoperative CT scans showed evidence of residual or possibly recurrent tumor within 1.5 to 4.5 months. Resolution of the tumor mass and contrast enhancement took 9 to 151 weeks; the time to resolution did not depend upon the configuration of the remaining tumor mass and contrast enhancement after surgery. In this study, patients with malignant gliomas whose CT scans eventually showed sustained complete disappearance of the tumor mass and contrast enhancement had a more favorable prognosis than did patients whose CT scans showed improvement, but not complete disappearance, of the tumor. These CT findings may prove useful in determining the prognosis of patients with malignant gliomas.
The terminal vascular bed in the superficial cortex of the rat
Authors: Motti Enrico D. F. , Imhof Hans-Georg , Yaşargil M. Gazi
Published: May 2009

✓ The capillaries in the vascular bed of the rat brain have been investigated by means of scanning electron microscopy of corrosion casts. A technique is described that allowed the finer ramifications to be observed. A series of representative sites from the arteriovenous terminal pathway are described in detail. Contrary to previous reports, the dichotomic pattern of vessel distribution is shown to prevail over the network pattern. Arteriovenous shunts of discrete size were not seen.“Thoroughfare channels” could be recognized. The findings are considered in light of current physiological knowledge, and their significance for microcerebrovascular flow is indicated.