bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subarachnoid hemorrhage as a cause of an adaptive response in cerebral arteries
Authors: Stoodley Marcus , Macdonald R. Loch , Weir Bryce , Marton Linda S. , Johns Lydia , Du Zhang Zhen , Kowalczuk Andrew 
Published: May 2009

Object. It is not known whether the factors responsible for vasospasm after subarachnoid hemorrhage (SAH) cause the cerebral arteries to be narrowed independent of the subarachnoid blood clot or whether the continued presence of clot is required for the entire time of vasospasm. The authors undertook the present study to investigate this issue.Methods. To distinguish between these possibilities, bilateral SAH was induced in monkeys. The diameters of the monkeys' cerebral arteries were measured on angiograms obtained on Days 0 (the day of SAH), 1, 3, 5, 7, and 9. The subarachnoid blood clot was removed surgically on Day 1, 3, or 5 or, in control animals, was not removed until the animals were killed on Day 7 or 9. The concentrations of hemoglobins and adenosine triphosphate (ATP), substances believed to cause vasospasm, were measured in the removed clots and the contractile activity of the clots was measured in monkey basilar arteries in vitro. If the clot was removed 1 or 3 days after placement, vasospasm was significantly diminished 4 days after clot removal. Clot removal on Day 5 had no marked effect on vasospasm. There was a significant decrease over time in hemoglobin and ATP concentrations and in the contractile activity of the clots, although substantial hemoglobin and contractile activity was still present on Day 7.Conclusions. The authors infer from these results that vasospasm requires the presence of subarachnoid blood for at least 3 days, whereas by Day 5 vasospasm is less dependent on subarachnoid blood clot. Because the clot still contains substantial amounts of hemoglobin and contractile activity after 5 days, there may be an adaptive response in the cerebral arteries that allows them to relax in the presence of the stimulus that earlier caused contraction.
A new device for endoscopic third ventriculostomy
Authors: Decq Philippe , Le Guerinel Caroline , Palfi Stéphane , Djindjian Michel , Kéravel Yves , Nguyen Jean-Paul 
Published: May 2009

✓ Since its description by Dandy in 1922, several techniques have been used to perform third ventriculostomy under endoscopic control. Except for the blunt technique, in which the endoscope is used by itself to create the opening in the floor of the third ventricle, the other techniques require more than one instrument to perforate the floor of the ventricle and enlarge the ventriculostomy. The new device described is a sterilizable modified forceps that allows both the opening of the floor and the enlargement of the ventriculostomy in a simple and effective way.The new device has the following characteristics: 1) the tip of the forceps is thin enough to allow the easy perforation of the floor of the ventricle; 2) the inner surface of the jaws is smooth to avoid catching vessels of the basal cistern; and 3) the outer surface of the jaws has indentations that catch the edges of the opening to prevent them from slipping along the instrument's jaws. The ventricle floor is opened by gentle pressure of the forceps, which is slowly opened so that the edges of the aperture are caught by the distal outer indentation of the jaws, leading to an approximately 4-mm opening of the floor. This device has been used successfully in 10 consecutive patients.This new device allows surgeons to perform third ventriculostomy under endoscopic control in a very simple, quick, and effective way, avoiding the need for additional single-use instruments.
Effect of long-term mild hypothermia therapy in patients with severe traumatic brain injury: 1-year follow-up review of 87 cases
Authors: Jiang Ji-Yao , Yu Ming-Kun , Zhu Cheng 
Published: May 2009

Object. The goal of this study was to investigate the protective effects of long-term (3–14 days) mild hypothermia therapy (33–35°C) on outcome in 87 patients with severe traumatic brain injury (TBI) (Glasgow Coma Scale score ≤ 8).Methods. In 43 patients assigned to a mild hypothermia group, body temperatures were cooled to 33 to 35°C a mean of 15 hours after injury and kept at 33 to 35°C for 3 to 14 days. Rewarming commenced when the individual patient's intracranial pressure (ICP) returned to the normal level. Body temperatures in 44 patients assigned to a normothermia group were maintained at 37 to 38°C. Each patient's outcome was evaluated 1 year later by using the Glasgow Outcome Scale. One year after TBI, the mortality rate was 25.58% (11 of 43 patients) and the rate of favorable outcome (good recovery or moderate disability) was 46.51% (20 of 43 patients) in the mild hypothermia group. In the normothermia group, the mortality rate was 45.45% (20 of 44 patients) and the rate of favorable outcome was 27.27% (12 of 44 patients) (p < 0.05). Induced mild hypothermia also markedly reduced ICP (p < 0.01) and inhibited hyperglycemia (p < 0.05). The rates of complication were not significantly different between the two groups.Conclusions. The data produced by this study demonstrate that long-term mild hypothermia therapy significantly improves outcomes in patients with severe TBI.
Risk of rupture from incidental cerebral aneurysms
Authors: Tsutsumi Kazuo , Ueki Keisuke , Morita Akio , Kirino Takaaki 
Published: May 2009

Object. Controversy still exists about the risk estimation for rupture of untreated saccular aneurysms presenting for causes other than subarachnoid hemorrhage (SAH). The object of this study was to address this issue.Methods. Between January 1976 and December 1997 in the Aizu Chuou Hospital, 62 patients underwent observation for more than 6 months for saccular, nonthrombotic, noncalcified unruptured aneurysms at locations not related to the cavernous sinus, which were detected in cerebral angiography studies performed for causes other than SAH. Clinical follow-up data in those 62 patients were reviewed to identify the risk of SAH.All patients were followed until July 1998, with the observation period ranging from 6 months to 17 years (mean 4.3 years). Seven patients (11.3%) developed SAH confirmed on computerized tomography (CT) scanning at a mean interval of 4.8 years, six of whom died and one of whom recovered with a major deficit. In addition, one patient died of the mass effect of the aneurysm, and another after sudden onset of headache and vomiting. The 5- and 10-year cumulative risks of CT-confirmed SAH calculated by the Kaplan—Meier method were 7.5% and 22.1%, respectively, for total cases, 33.5% and 55.9%, respectively, for large (> 10 mm) aneurysms, and 4.5% and 13.9%, respectively, for small (< 10 mm) aneurysms.Conclusions. Although based on a relatively small, single-institution series, our data indicated that the risk of rupture from incidental, intradural, saccular aneurysms was higher than previously reported, and may support preventive surgical treatment of incidental aneurysms, considering the fatality rate of SAH.
Continuous electromyography monitoring of motor cranial nerves during cerebellopontine angle surgery
Authors: Romstöck Johann , Strauss Christian , Fahlbusch Rudolf 
Published: May 2009

Object. Electromyography (EMG) monitoring is expected to reduce the incidence of motor cranial nerve deficits in cerebellopontine angle surgery. The aim of this study was to provide a detailed analysis of intraoperative EMG phenomena with respect to their surgical significance.Methods. Using a system that continuously records facial and lower cranial nerve EMG signals during the entire operative procedure, the authors examined 30 patients undergoing surgery on acoustic neuroma (24 patients) or meningioma (six patients). Free-running EMG signals were recorded from muscles targeted by the facial, trigeminal, and lower cranial nerves, and were analyzed off-line with respect to waveform characteristics, frequencies, and amplitudes. Intraoperative measurements were correlated with typical surgical maneuvers and postoperative outcomes.Characteristic EMG discharges were obtained: spikes and bursts were recorded immediately following the direct manipulation of a dissecting instrument near the cranial nerve, but also during periods when the nerve had not yet been exposed. Bursts could be precisely attributed to contact activity. Three distinct types of trains were identified: A, B, and C trains. Whereas B and C trains are irrelevant with respect to postoperative outcome, the A train—a sinusoidal, symmetrical sequence of high-frequency and low-amplitude signals—was observed in 19 patients and could be well correlated with additional postoperative facial nerve paresis (in 18 patients).Conclusions. It could be demonstrated that the occurrence of A trains is a highly reliable predictor for postoperative facial palsy. Although some degree of functional worsening is to be expected postoperatively, there is a good chance of avoiding major deficits by warning the surgeon early. Continuous EMG monitoring is superior to electrical nerve stimulation or acoustic loudspeaker monitoring alone. The detailed analysis of EMG-waveform characteristics is able to provide more accurate warning criteria during surgery.
Diffuse axonal injury due to lateral head rotation in a rat model
Authors: Xiao-Sheng He , Sheng-Yu Yi , Xiang Zhang , Zhou Fei , Jian-Ning Zhang , Li-Sun Yang 
Published: May 2009

Object. The authors investigated the ramifications of producing diffuse axonal injury (DAI) by lateral head rotation in a rat model.Methods. Using a special injury-producing device, the rat's head was rapidly rotated 90° in the coronal plane at an angular velocity of at least 753.13 rad/second and an angular acceleration of at least 1.806 × 105 rad/second2; the rotation was complete within 2.09 msec. There were no statistically significant changes in PO2, PCO2, pH, or blood pressure values at 5, 15, or 60 minutes after head rotation compared with their respective preinjury baseline values. The rats exhibited posttraumatic behavior suppression for an average of 12.6 minutes. The mortality rate was 17%. The rats that survived had diffuse subarachnoid hemorrhage around the brainstem and upper cervical cord, but no obvious brain contusion. In sections stained with silver or hematoxylin and eosin, axonal swelling and bulblike protrusions at the axonal axis were observed in the medulla oblongata, midbrain, upper cervical cord, and corpus callosum between 6 hours and 144 hours postinjury. The axonal injuries were most severe in the brainstem and were accompanied by parenchymal bleeding. The density of bulblike axonal protrusions peaked 6 hours postinjury in the medulla oblongata and 24 hours postinjury in the midbrain.Conclusions. Rapid lateral head rotation can produce DAI characterized by severe damage to the rat brainstem.
Dexamethasone-induced abolition of the inflammatory response in an experimental glioma model: a flow cytometry study
Authors: Badie Behnam , Schartner Jill M. , Paul Jasmeet , Bartley Becky A. , Vorpahl Jessica , Preston J. Keith 
Published: May 2009

Object. Commonly used for management of cerebral edema in patients with brain tumors, steroid medications also have immunosuppressive functions. To characterize the effects of steroids on the central nervous system's response to tumors more clearly, flow cytometry was used to quantify the extent of inflammatory cell infiltration in an immunogenic rat glioma model.Methods. Freshly prepared 11-day-old intracranial C6 tumors that had been excised from dexamethasone-treated and untreated rats were labeled ex vivo with monoclonal antibodies against CD11b/c, CD45, and CD8a antigens. The extent of microglia (CD11b/c—highly positive, CD45—slightly positive cell), macrophage (CD11b/c—highly positive, CD45—highly positive cell), lymphocyte (CD11b/c-negative, CD45—highly positive cell), and cytotoxic T-cell (CD8a-positive cell) infiltration into each rat's tumor, tumor periphery, and contralateral tumor-free hemisphere was analyzed using flow cytometry.Microglia and lymphocytes constituted a significant component of infiltrating cells in this model, comprising 23 ± 3% and 33 ± 5% of viable cells, respectively. Macrophages, on the other hand, accounted for only 9 ± 1% of infiltrating cells. Treatment of rats with a 7-day course of low-dose dexamethasone (0.1 mg/kg/day) resulted in a greater than 50% inhibition of microglia (p = 0.03) and lymphocyte (p = 0.001) infiltration into tumors. Increasing the dexamethasone dose to 1 mg/kg/day further abolished lymphocyte infiltration (89% inhibition, p = 0.001) but had no additional inhibitory effect on microglia invasion. Macrophage infiltration of tumors was not inhibited at the dexamethasone doses used in this study (p = 0.42).Conclusions. Flow cytometry is a valuable technique for characterizing tumor-associated inflammatory cells in gliomas. Even at low doses, dexamethasone was found to inhibit significantly the infiltration of brain tumors by lymphocytes and microglia. These findings should be considered when experimental immunotherapeutic strategies are evaluated for clinical application.
Role of calcium channels in oxyhemoglobin-induced apoptosis in endothelial cells
Authors: Meguro Toshinari , Klett Christoph P. R. , Chen Betty , Parent Andrew D. , Zhang John H. 
Published: May 2009

Object. Oxyhemoglobin (OxyHb) released from hemolysed erythrocytes has been considered to be responsible for cerebral vasospasm after subarachnoid hemorrhage. The authors previously reported that OxyHb produced apoptosis in cultured vascular endothelial cells. The change in intracellular Ca++ homeostasis was expected to be one of the possible mechanisms of the cytotoxic effects of OxyHb. This study was undertaken to investigate the protective effects of Ca++-channel blockers on OxyHb-induced apoptosis.Methods. Cultured bovine coronary artery and brain microvascular endothelial cells (passages 5–9) were used. A cell density study, immunohistochemical staining, and DNA fragmentation analysis were performed to confirm apoptosis. Various concentrations (1–50 µM) of OxyHb were used for 24- to 72-hour incubations with and without Ca++-channel blockers.Oxyhemoglobin produced cytotoxicity leading to cell detachment from the culture dish in time- and concentration-dependent manners. The highest dose (50 µM) of OxyHb produced cell detachment after a 24-hour incubation, and the lower doses (1–10 µM) produced cell detachment after 48 to 72 hours. Immunohistochemical analysis showed that apoptosis occurred in cells that were still attached to the side of the culture dish after 48 to 72 hours of OxyHb treatment (5 µM). The OxyHb (10 µM) produced DNA ladders at 48 to 72 hours. Three Ca++-channel blockers were used to prevent the toxic effect of OxyHb. The voltage-dependent Ca++-channel blocker nicardipine (1 µM), the voltage-independent Ca++-channel blocker econazole (10 µM), and the inorganic Ca++-channel blocker lanthanum (100 µM) all failed to prevent cell detachment or DNA ladders produced by OxyHb. These results were similar in both cell lines.Conclusions. Oxyhemoglobin produced apoptotic changes in cultured vascular endothelial cells, and Ca++-channel blockers did not prevent OxyHb-induced apoptosis.
Relationship between residual cerebral blood flow and oxygen metabolism as predictive of ischemic tissue viability: sequential multitracer positron emission tomography scanning of middle cerebral artery occlusion during the critical first 6 hours after stroke in pigs
Authors: Sakoh Masaharu , Østergaard Leif , Røhl Lisbeth , Smith Donald F. , Simonsen Claus Z. , Sørensen Jens Christian , Poulsen Peter V. , Gyldensted Carsten , Sakaki Saburo , Gjedde Albert 
Published: May 2009

Object. The authors tested the hypothesis that oxygen metabolism is the key factor linking the long-term viability of ischemic brain tissue to the magnitude of residual blood flow during the first 6 hours following a stroke.Methods. Eleven anesthetized pigs underwent a series of positron emission tomography studies to measure cerebral blood flow (CBF) and metabolism before and for 7 hours after the animals were subjected to permanent middle cerebral artery (MCA) occlusion. The extent of collateral blood supply was assessed using angiography. Abnormal metabolism of the ischemic tissue progressed as a function of time in inverse proportion to the magnitude of residual CBF, and the volume of the infarct grew in inverse proportion to the residual blood supply. Ten hours after occlusion of the MCA, the infarct topographically matched the tissue with a cerebral metabolic rate of oxygen consumption below 50% of values measured on the contralateral side. This was also the threshold for the decline of the oxygen extraction fraction below normal, which was critical for the prediction of nonviable ischemic tissue. Mildly ischemic tissue (CBF > 30 ml/100 g/min) did not reach the cerebral metabolic rate of oxygen threshold of viability during the first 6 hours after MCA occlusion; moderately ischemic tissue (CBF 12–30 ml/100 g/ min) reached the threshold of viability in 3 hours; and severely ischemic tissue (CBF < 12 ml/100 g/min) remained viable for less than 1 hour.Conclusions. The relationship between the residual CBF and both oxygen metabolism and extraction is critical to the evolution of metabolic deficiency and lesion size after stroke.
Electrophysiological localization of the substantia nigra in the parkinsonian nonhuman primate
Authors: Starr Philip A. , Subramanian Thyagarajan , Bakay Roy A. E. , Wichmann Thomas 
Published: May 2009

✓ During ablative surgery and implantation of deep-brain stimulators for the treatment of movement disorders, electrophysiological techniques are often used for localization of subcortical targets. New restorative therapies for Parkinson disease, aimed at delivering drugs or cells to the substantia nigra (SN), are becoming available. Therefore, precise surgical approaches to the dopaminergic cell—containing region of the SN are required to avoid damage to nearby structures such as the corticospinal tract and subthalamic nucleus. In a study conducted in nonhuman primates, the authors evaluated the utility and accuracy of electrophysiological techniques in localizing the SN.Three adult rhesus monkeys were used as hosts for intranigral cell transplants. The monkeys were rendered hemiparkinsonian by intracarotid injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. With the aid of stereotactic guidance, chronic recording chambers were placed on the skull of each monkey and directed at the SN. In each monkey, 20 to 40 trajectories were explored with a microelectrode. Spontaneous and movement-related single-unit activities were recorded in the SN, pars reticulata, subthalamic nucleus, globus pallidus, striatum, thalamus, and red nucleus. Motor and ocular responses to microstimulation in the subthalamic area were noted. Using the electrophysiological and stereotactic information that was obtained, three-dimensional maps of the nigral complex were constructed to infer the location of the SN pars compacta. The maps were subsequently used to guide intranigral placement of fetal dopaminergic cells. Accurate delivery was verified by histological analysis.Based on the characteristic electrophysiological properties of the SN and surrounding structures in the parkinsonian state, microelectrode recording techniques may be used to ensure accurate placement of cell transplantation in the intranigral region.
Use of titanium mesh for reconstruction of large anterior cranial base defects
Authors: Badie Behnam , Preston J. Keith , Hartig Gregory K. 
Published: May 2009

✓ The authors evaluated the role of titanium mesh used in combination with vascularized pericranium to provide rigid support during reconstruction of anterior skull base defects.Thirteen patients with large anterior skull base defects caused by tumor invasion or traumatic injury involving the cribriform plate, orbital roof, and planum sphenoidale were included in the study. The reconstruction technique involved placement of titanium mesh between two layers of continuous vascularized pericranium. Surgical glue and routine lumbar cerebrospinal fluid (CSF) drainage were not used in any patient.At a mean postoperative follow-up time of 22 months (range 8–39 months), none of the patients had developed infection or meningocele. Postoperative CSF rhinorrhea occurred in two patients with extensive dural defects, which resolved with temporary lumbar drainage.Use of titanium mesh and a two-layer vascularized pericranial graft is a safe, reproducible, and feasible method for reconstructing the anterior skull base. Patients with large dural defects may need temporary CSF diversion to avoid postoperative fistula formation.
Radiosurgery for Cushing's disease after failed transsphenoidal surgery
Authors: Sheehan Jonas M. , Vance Mary L. , Sheehan Jason P. , Ellegala Dilantha B. , Laws Edward R. 
Published: May 2009

Object. Although transsphenoidal surgery has become the standard of care for Cushing's disease, it is often unsuccessful in normalizing cortisol production. In this study the authors investigate the safety and efficacy of gamma knife radiosurgery (GKRS) for Cushing's disease after failed transsphenoidal surgery.Methods. The records of all patients who underwent GKRS at the authors' institution after unsuccessful transsphenoidal surgery for Cushing's disease were retrospectively reviewed. Successful treatment was considered a normal or below-normal 24-hour urinary free cortisol (UFC) level. Records were also evaluated for relapse, new-onset endocrine deficiencies, interval change in tumor size, and visual complications.Forty-three patients underwent 44 gamma knife procedures with follow up ranging from 18 to 113 months (mean 39.1, median 44 months). Normal 24-hour UFC levels were achieved in 27 patients (63%) at an average time from treatment of 12.1 months (range 3–48 months). Three patients had a recurrence of Cushing's disease at 19, 37, and 38 months, respectively, after radiosurgery. New endocrine deficiencies were noted in seven patients (16%). Follow-up magnetic resonance images obtained in 33 patients revealed a decrease in tumor size in 24, no change in nine, and an increase in size in none of the patients. One patient developed a quadrantanopsia 14 months after radiosurgery despite having received a dose of only 0.7 Gy to the optic tract.Conclusions. Gamma knife radiosurgery appears to be safe and effective for the treatment of Cushing's disease refractory to pituitary surgery. Delayed recurrences and new hormone deficiencies may occur, indicating the necessity for regular long-term follow up.