bluuebunny/crossref_metadata_2025 huggingface dataset:
The sequential hook insertion technique for universal spine instrumentation application
Authors: Benzel Edward C. , Ball Perry A. , Baldwin Nevan G. , Marchand Erich P.
Published: May 2009

✓ A new technique of universal spine instrumentation insertion for the management of thoracic and lumbar spine instability is presented and the results in 10 patients are described. The technique involves the sequential insertion of Texas Scottish Rite Hospital (TSRH) central-post hooks, followed by hook fixation to the rod; force is then applied with correction of deformity, if needed. This allows for methodical, safe, and rapid instrumentation insertion. The new TSRH central-post hook configuration permits manipulation of the hook/rod relationships to the advantage of the surgeon (and patient) by providing more room for both hook insertion and hook/rod fixation. This technique has reduced operative time, facilitated case of deformity correction, and provided uniformly acceptable early postsurgical results.
A new device for cortical stimulation mapping of surgically unexposed cortex
Authors: Silbergeld Daniel L.
Published: May 2009

✓ Intraoperative functional mapping is an integral facet of many supratentorial procedures involving cortical resection. A new device is described that can be used in conjunction with a standard cortical stimulator and strip electrodes to stimulate intraoperative regions of unexposed cerebral cortex. This permits the use of a smaller craniotomy, while providing the ability for functional mapping of large areas of surface cortex.
Variables affecting the accuracy of stereotactic localization using computerized tomography
Authors: Bucholz Richard D. , Ho Hector W. , Rubin Jason P.
Published: May 2009

✓ Stereotactic localization using computerized tomography (CT) is increasingly employed to guide neurosurgical procedures in crucial areas of the brain such as the brain stem. This technique allows the surgeon to resect a lesion in its entirety while sparing critical areas of the brain. Thus, the parameters used for scanning should be selected for maximum accuracy. While the small pixel size of CT scanners suggests a high degree of precision in localization, there have been few systematic studies of this accuracy. The authors have studied the amount of error in localization created by variables such as CT scan thickness, interscan spacing, size of lesion, and method of computation when using the Brown-Roberts-Wells (BRW) stereotactic system.

Over 1000 CT scans were made of a phantom composed of spheres of differing diameter and location. The CT slice thickness was varied from 1.5 to 5.0 mm, and interscan spacing was varied from 0.5 to 3.0 mm. The coordinates of the center of the spheres were calculated independently using the laptop computer supplied with the unit and also by a stereotactic computer which automatically calculates the center of the fiducials. The actual BRW coordinates of the sphere center were obtained using the phantom base and were then compared to the computer-calculated coordinates to determine error in localization.

Variables with a significant effect on error included the scan thickness, interscan spacing, and sphere size. The mean error decreased 23% as the scan thickness decreased from 5.0 to 1.5 mm and 45% as the interscan spacing decreased from 3.0 to 0.5 mm. Mean error was greatest for the smallest sphere sizes. The two computational methods did not differ in error. This study suggests that, for critical areas of the brain or for small lesions, a scan thickness of 1.5 mm and interscan spacing of 0.5 mm should be employed.
Surgery for angiographically occult cerebral aneurysms
Authors: Jafar Jafar J. , Weiner Howard L.
Published: May 2009

✓ In 15% of patients with spontaneous subarachnoid hemorrhage (SAH), the source of bleeding cannot be determined despite repeated cerebral angiography. However, some patients diagnosed as having “SAH of unknown cause” actually harbor undetected aneurysms. The authors report six patients with SAH who, despite multiple negative cerebral angiograms, underwent exploratory surgery due to a high clinical and radiographic suspicion for the presence of an aneurysm. Brain computerized tomography (CT) scans revealed blood located mainly in the basal frontal interhemispheric fissure in four patients, in the sylvian fissure in one patient, and in the interpeduncular cistern in one patient. The patients were evaluated as Hunt and Hess Grades I to III, and had undergone at least two high-quality cerebral angiograms that did not reveal an aneurysm. Vasospasm was visualized in two patients. Three patients rebled while in the hospital. Exploratory surgery was performed at an average of 12 days post-SAH. Five aneurysms were discovered at surgery and were successfully clipped. All four patients with interhemispheric blood were found to have an anterior communicating artery (ACoA) aneurysm. The patient with blood in the sylvian fissure was found to have a middle cerebral artery aneurysm. These aneurysms were partially thrombosed. No aneurysm was detected in the patient with interpeduncular SAH, despite extensive basilar artery exploration. Five patients had an excellent outcome and one patient developed diabetes insipidus. These results show that exploratory aneurysm surgery is warranted, despite repeated negative cerebral angiograms, if the patient manifests the classical signs of SAH with CT scans localizing blood to a specific cerebral blood vessel (particularly the ACoA) and if a second SAH is documented at the same site.
Partial sensory trigeminal rhizotomy at the pons for trigeminal neuralgia
Authors: Young Jacob N. , Wilkins Robert H.
Published: May 2009

✓ Microvascular decompression is preferred among open procedures for the treatment of trigeminal neuralgia. However, in some cases the decompression cannot be performed, either because no significant vascular compression of the trigeminal nerve is found at surgery or because a patient's vascular anatomy makes it unsafe. Partial sensory rhizotomy is a commonly used alternative in these instances. The outcome after partial sensory rhizotomy was reviewed retrospectively in 83 patients with an average follow-up period of 72 months. Sixty-four (77%) of these patients had no evidence of vascular contact at operation. The remaining 19 patients (23%) had vascular structures in proximity to the trigeminal nerve but still underwent partial sensory rhizotomy in place of or in addition to microvascular decompression either because the offending vessel could not be moved adequately (11 cases) or because the vascular contact was considered insignificant (eight cases). Outcome was classified as: excellent if there was no trigeminal neuralgia postoperatively; good if pain persisted or recurred but was less severe than preoperatively; and poor if persistent or recurrent pain was equal to or greater than the preoperative pain in severity and was refractory to medication, or was severe enough to require additional surgery. The outcome was excellent in 40 patients (48%), good in 18 (22%), and poor in 25 (30%); follow-up durations were similar for the three outcome categories. The failure rate was 17% for the 1st year and averaged 2.6% each year thereafter. Two variables were predictive of a poor outcome: prior surgery and lack of preoperative involvement of the third trigeminal division. Major complications occurred in 4% of cases and minor complications in 11%. The authors conclude that partial sensory rhizotomy is a safe and effective alternative to microvascular decompression when neurovascular compression is not identified at operation or when microvascular decompression cannot be performed for technical reasons.
Cerebral blood flow decreased by adrenergic stimulation of cerebral vessels in anesthetized newborn pigs with traumatic brain injury
Authors: Shibata Masaaki , Einhaus Stephanie , Schweitzer John B. , Zuckerman Samuel , Leffler Charles W.
Published: May 2009

✓ Changes in cerebral blood flow (CBF), pial arteriolar diameter, and arterial blood pressure, gases, and pH were examined before and for 3 hours after fluid-percussion brain injury in α-chloralose-anesthetized piglets. The brain injury was induced by a percussion of 2.28 ± 0.06 atm applied for 23.7 ± 0.5 msec to the right parietal cortex. Regional CBF was measured with radiolabeled microspheres, and changes in pial arteriolar diameter were monitored in the left parietal cortex using closed cranial windows. Immediately following brain injury, mean blood pressure transiently (for approximately 10 minutes) either increased or decreased and then exhibited a prolonged decrease in all of the animals. The brains showed changes consistent with traumatic brain injury such as subarachnoid hemorrhage, contusions, or reactive axonal swelling; none showed histological evidence of a global alternative pathogenetic mechanism such as hypoxic ischemic damage. While CBF of uninjured control animals did not change over a 3-hour observation period, after brain injury blood flow decreased 30% ± 1% below the baseline level within 10 minutes and remained there for 2 to 3 hours posttrauma. After adrenergic blockade, CBF did not decrease at any time during the 3-hour period in either the uninjured control or the injured animals. Concomitant with the decreased blood flow after brain injury, pial arteriolar diameter decreased 14% below the preinjury level. However, in piglets treated with adrenoceptor antagonists, uninjured control and brain-injured animals did not show a decrease in pial arteriolar diameter. The present results support the hypothesis that increased sympathetic outflow to the cephalic vasculature following the fluid-percussion brain injury causes cerebral vasoconstriction decreasing pial arteriolar diameter and regional CBF.
Catecholamine response to a gradual increase of intracranial pressure
Authors: van Loon Johan , Shivalkar Bharati , Plets Chris , Goffin Jan , Tjandra-Maga T. Budya , Flameng Wim
Published: May 2009

✓ To determine the catecholamine response to progressive intracranial hypertension, intracranial pressure (ICP) was raised gradually by continuous expansion of an epidural balloon in seven dogs. Hemodynamic parameters, ICP, and cerebral perfusion pressure (CPP) were monitored continuously and serum catecholamine levels began to rise when CPP was in the low-positive range (20 to 30 mm Hg), reaching a peak just after brain death (CPP ≤ 0 mm Hg). There was no correlation between ICP and the catecholamine peak. Compared to control values, the mean increase was 286-fold for epinephrine and 78-fold for norepinephrine. Temporally, the catecholamine peak corresponded well with the observed hemodynamic changes. These results suggest that ischemia in certain parts of the brain stem is responsible for the hemodynamic changes observed in intracranial hypertension (such as the Cushing response), and they show that catecholamines play an important role in these hemodynamic changes.
Altered response to histamine in brain tumor vessels: the selective increase of regional cerebral blood flow in transplanted rat brain tumor
Authors: Nomura Tomojirou , Ikezaki Kiyonobu , Natori Yoshihiro , Fukui Masashi
Published: May 2009

✓ The authors studied the effect of intracarotid administration of histamine on the regional cerebral blood flow (rCBF) in transplanted rat C6 glioma by the hydrogen clearance method. Histamine infusion at doses of 1 and 10 µg/kg/min produced an increase of rCBF in the tumor (24.6% ± 16.4%, p < 0.002, and 37.6% ± 18.2%, p < 0.0001, respectively) and also in brain surrounding the tumor (26.8% ± 16.2%, p < 0.002, and 34.9% ± 9.2%, p < 0.0001, respectively) without any significant changes in the ipsilateral hemisphere. Intravenous administration of pyrilamine (H1antagonist) and cimetidine (H2antagonist) reduced blood flow responses to histamine; cimetidine was a more effective blocking agent than pyrilamine. Intracarotid infusion of histamine (1 and 10 µg/kg/min) with intravenous injection of Evans blue dye disclosed the selective extravasation of dye in the tumor and the brain surrounding the tumor.

These results indicated that brain tumor vessels could respond to histamine differently than normal brain capillaries. The mechanism of selective response to histamine could be explained either by increased permeability or by altered characteristics of histamine receptors in the tumor vessels.
Limiting ischemic spinal cord injury using a free radical scavenger 21-aminosteroid and/or cerebrospinal fluid drainage
Authors: Francel Paul C. , Long Bruce A. , Malik Jacek M. , Tribble Curtis , Jane John A. , Kron Irving L.
Published: May 2009

✓ Traumatic spinal cord injury occurs in two phases: biomechanical injury, followed by ischemia and reperfusion injury. Biomechanical injury to the spinal cord, preceded or followed by various pharmaceutical manipulations or interventions, has been studied, but the ischemia/reperfusion aspect of spinal cord injury isolated from the biomechanical injury has not been previously evaluated. In the current study, ischemia to the lumbar spinal cord was induced in albino rabbits via infrarenal aortic occlusion, and two interventions were analyzed: the use of U74006F (Tirilazad mesylate), a 21-aminosteroid, and cerebrospinal fluid (CSF) drainage. These treatment modalities were tested alone or in combination.

In Phase 1 of this study, the rabbits received 1.0 mg/kg of Tirilazad or an equal volume of vehicle (controls) prior to the actual occlusion, three doses of Tirilazad (1 mg/kg each) during the occlusion, then several doses after the occlusion. Of the Tirilazad-treated animals, 30% became paraplegic while 70% of the control animals became paraplegic. Phase 2 involved the same doses of Tirilazad as in Phase 1 and, in addition, CSF pressure monitoring and drainage were performed. The paraplegia rate was 79% in the control animals, 36% in the group receiving Tirilazad alone, 25% in the group with CSF drainage alone, and 20% in the Tirilazad plus CSF drainage group. This rate also correlated with changes noted in CSF pressure; both Tirilazad administration alone and CSF drainage alone induced a decrease in CSF pressure and the two combined produced a further decrease. There was marked improvement in the perfusion pressure when using Tirilazad alone, CSF drainage alone, and Tirilazad therapy in combination with CSF drainage, with the last group producing the largest increase. This change in CSF pressure and perfusion pressure correlated with improved functional neurological outcome. Pathological examination revealed that Tirilazad therapy reduced the extensive and diffuse neuronal, glial, and endothelial damage to (in its most severe form) a more patchy focal region of damage in the gray matter. Cerebrospinal fluid drainage resulted in pyknosis of some motor neurons, and some eosinophilia. The combination of CSF drainage and Tirilazad administration resulted in the least abnormality, with either normal or near-normal spinal cords.

It is concluded that Tirilazad administration decreased CSF pressure during spinal cord ischemia and reperfusion and, like CSF drainage, increased and improved the perfusion pressure to the spinal cord, decreased spinal cord damage, and improved functional outcome. These effects may be related to the role that Tirilazad has on free radical scavenging during ischemia and reperfusion, and it is possible that Tirilazad therapy alone or in combination with CSF drainage is an effective adjunct to other neural protective measures in spinal cord injury.
Superficial siderosis of the central nervous system: magnetic resonance imaging and pathological correlation
Authors: Janss Anna J. , Galetta Steven L. , Freese Andrew , Raps Eric C. , Curtis Mark T. , Grossman Robert I. , Gomori John M. , Duhaime Ann C.
Published: May 2009

✓ The authors report a 32-year-old woman who had undergone repair of an occipital encephalocele in infancy and who experienced a 20-year history of progressive hearing loss and intermittent vertigo. After parturition, she developed a rapidly progressive quadriparesis and brain-stem dysfunction associated with persistent intraventricular and subarachnoid hemorrhage. Serial magnetic resonance (MR) images showed progressive deposition of hemosiderin along the surface of the brain, brain stem, and spinal cord, and enhanced thickened membranes at the site of the original encephalocele repair. Posterior fossa exploration disclosed hemorrhagic membranes, which were resected; despite removal of this tissue, the patient deteriorated and died. Postmortem examination confirmed iron-containing pigment along the meninges, cerebral hemispheres, brain stem, spinal cord, and cranial nerves accompanied by atrophy of the superficial cerebellar cortex.

It is concluded that superficial siderosis may accompany encephalocele repair. This is believed to be the first report in the literature of superficial siderosis of the central nervous system to correlate in vivo MR images with autopsy results.
Localized hypertrophic mononeuropathy involving spinal roots and associated with sacral meningocele
Authors: Yassini Patrick R. , Sauter Kent , Schochet Sydney S. , Kaufman Howard H. , Bloomfield Stephen M.
Published: May 2009

✓ Hypertrophic nerve lesions displaying onion-bulb cellular formations are quite rare in the absence of a generalized hypertrophic neuropathy. The isolated peripheral nerve lesion has been termed “localized hypertrophic mononeuropathy” (LHN), and fewer than 30 cases of this condition have been reported. Very little is known regarding the etiology and the natural course of this rare disorder. A unique case of LHN afflicting spinal roots in association with a sacral meningocele is reported with a brief review of the relevant literature. The unique features of this case not only reveal a variable clinical presentation of the disease but also support the theory that LHN may be a localized reaction to nerve trauma or entrapment.
Carotid artery revascularization following Crutchfield clamp placement
Authors: Helm Gregory A. , Simmons Nathan E. , diPierro Charles G. , Kassell Neal F.
Published: May 2009

✓ Several types of adjustable clamp have been widely utilized to gradually occlude the carotid artery for the treatment of various intracranial vascular lesions. A fairly large number of patients, many of whom have not been adequately followed, have these clamps still in place. The authors report two patients, initially treated with a Crutchfield clamp for an intracranial aneurysm, in whom carotid artery system revascularization occurred through the clamp many years later, leading to continued filling of the aneurysm. Recommendations are given on monitoring patients with Crutchfield clamps in order to minimize long-term complications.
Cerebral oxygen metabolism during hypothermic circulatory arrest in humans
Authors: Ausman James I. , McCormick Patrick W. , Stewart Melville , Lewis Gary , Dujovny Manuel , Balakrishnan Guruswamy , Malik Ghaus M. , Ghaly Ramsis F.
Published: May 2009

✓ Profound hypothermia with circulatory arrest is an important surgical adjuvant that allows protected cessation of cerebral blood flow for a brief period. In seven patients undergoing this procedure, continuous spectroscopic measurement of cerebral hemoglobin oxygen saturation was performed. Circulatory arrest at 18°C was associated with a significant progressive desaturation (p < 0.01) of residual cerebral hemoglobin. Arrest time varied based on operative complexity (range 10 to 65 minutes), and a negative linear correlation between arrest time (y) and oxygen saturation (x) was noted (y = −0.87x + 64). Five patients whose saturation remained above 35% had no neurological injury attributable to hypoxia. One patient (Hunt and Hess Grade 0) whose saturation fell below 35% had evidence of a global hypoxic injury at postmortem examination. Spectroscopically measured cerebral hemoglobin saturation (cerebral oximetry) may be used to monitor metabolic activity during circulatory arrest. Although the clinical utility of such monitoring cannot be established at this time, the potential may exist to prolong the safe duration of induced circulatory arrest for cerebral protection.
Surgical management of brain-stem tumors in children: results and statistical analysis of 75 cases
Authors: Pierre-Kahn Alain , Hirsch Jean-François , Vinchon Mathieu , Payan Christine , Sainte-Rose Christian , Renier Dominique , Lelouch-Tubiana Arielle , Fermanian Jacques
Published: May 2009

A study was made of 75 children treated between 1970 and 1990, with partial, subtotal, or total removal of three intrinsic and 72 exophytic or surface brain-stem tumors. In all cases, the goal of surgery was to remove as much tumor as possible. Extent of removal was defined according to data obtained from postoperative computerized tomography or magnetic resonance imaging, and was considered partial when only a small amount of tumor was removed, subtotal when a few cubic millimeters of tumor was left, and total when no residual tumor was seen on postoperative radiological investigations. An ultrasonic aspirator was used for the 43 most recent operations. Among tumor removals without the aspirator, 24 (75%) were partial, eight (25%) subtotal, and none total; with the use of the aspirator, the number of partial removals decreased to 44.5% while that of subtotal and total removals increased to 32% and 23.5%, respectively. There were 69 gliomas (92%) and 47 benign tumors (62.6%). Forty-nine patients were irradiated postoperatively, and 14 of the 23 patients whose benign tumors were removed totally or subtotally did not undergo irradiation.

This study showed that: 1) the overall prognosis of patients with malignant tumors was poor and was not improved by surgery; 2) the survival rate of those with benign tumors was significantly (p < 0.01) lower after partial removal than after total or subtotal removal (52% and 94%, respectively, at 5 years); 3) comparison of means and proportions (Student's and chi-squared tests) between benign and malignant tumors showed a significant difference relating to patient age (p < 0.03), peritumoral hypodensity (p < 0.001), and preoperative duration of symptoms (p < 0.001); 4) stepwise logistic regression analysis confirmed that two of these three variables were related to malignancy: namely, patient age at surgery (p < 0.03) and presence of peritumoral hypodensity (p < 0.001); and 5) routine postoperative irradiation was contraindicated after total or subtotal removal of benign tumors.
Plasma glucose levels and outcome after aneurysmal subarachnoid hemorrhage
Authors: Lanzino Giuseppe , Kassell Neal F. , Germanson Teresa , Truskowski Laura , Alves Wayne
Published: May 2009

✓ Plasma glucose levels were studied in 616 patients admitted within 72 hours after subarachnoid hemorrhage (SAH). Glucose levels measured at admission showed a statistically significant association with Glasgow Coma Scale scores, Botterell grade, deposition of blood on computerized tomography (CT) scans, and level of consciousness at admission. Elevated glucose levels at admission predicted poor outcome. A good recovery, as assessed by the Glasgow Outcome Scale at 3 months, occurred in 70.2% of patients with normal glucose levels (≤ 120 mg/dl) and in 53.7% of patients with hyperglycemia (> 120 mg/dl) (p = 0.002). The death rates for these two groups were 6.7% and 19.9%, respectively (p = 0.001). The association was still maintained after adjusting for age (> or ≤ 50 years) and thickness of clot on CT scans (thin or thick) in the subset of patients who were alert/drowsy at admission. Increased mean glucose levels between Days 3 and 7 also predicted a worse outcome; good recovery was observed in 132 (73.7%) of 179 patients who had normal mean glucose levels (≤ 120 mg/dl) and 160 (49.7%) of 322 who had elevated mean glucose levels (> 120 mg/dl) (p < 0.0001). Death occurred in 6.7% and 20.8% of the two groups, respectively (p < 0.0001). It is concluded that admission plasma glucose levels can serve as an objective prognostic indicator after SAH. Elevated glucose levels during the 1st week after SAH also predict a poor outcome. However, a causal link between hyperglycemia and outcome after delayed cerebral ischemia, although suggested by experimental data, cannot be established on the basis of this study.
Mechanism of oxyhemoglobin-induced release of endothelin-1 from cultured vascular endothelial cells and smooth-muscle cells
Authors: Kasuya Hidetoshi , Weir Bryce K. A. , White David M. , Stefansson Kari
Published: May 2009

✓ Release of endothelin-1 from cultured endothelial cells can be induced with oxyhemoglobin (oxyHb). The present study was conducted to explore whether oxyHb affects the release of endothelin-1 and the induction of endothelin-1 messenger ribonucleic acid (mRNA) and to examine the mechanism whereby oxyHb induces endothelin-1 production in cultured vascular smooth-muscle cells as well as in cultured endothelial cells.

Oxyhemoglobin produces concentration-dependent (0.1 to 10 µM) and time-dependent (0 to 24 hours) increases in immunoreactive endothelin-1 in conditioned medium from bovine arterial endothelial cells. Oxyhemoglobin induces immunoreactive endothelin-1 in rat aortic smooth-muscle cells in the same fashion, although the rate is 30-fold less than that of endothelial cells. This promoting effect is much higher than that of other stimulators such as thrombin and phorbol 12-myristate 13-acetate. Northern blot analysis of total RNA from endothelial cells also showed endothelin-1 mRNA induction. Staurosporine, a protein kinase C (PKC) inhibitor inhibited oxyHb-induced endothelin-1 production in both vascular endothelial and smooth-muscle cells, whereas an increase of intracellular cyclic adenosine monophosphate (cAMP) by forskolin or an addition of 8-bromo-cAMP only inhibited this effect in smooth-muscle cells.

These findings suggest that oxyHb-induced endothelin-1 production in endothelial cells is regulated by PKC, and in smooth-muscle cells by both PKC and the cAMP-dependent pathway. The production of endothelin, the most potent vasoconstrictor, in both vascular endothelial and smooth-muscle cells by oxyHb may have significance in the pathogenesis of cerebral vasospasm.
Subdural empyema of the cervical spine: clinicopathological correlates and magnetic resonance imaging
Authors: Levy Michael L. , Wieder Brian H. , Schneider John , Weiss Martin H.
Published: May 2009

✓ A paucity of formally described information is available in the scientific literature regarding spinal subdural empyema. Patients presenting with neurological deterioration associated with subdural empyema are rarely identified, and treatment is often based upon anecdotal cases. The authors contribute three cases of primary cervical spinal subdural empyema and review the seven found in the literature. All patients had clinical evidence of neurological compromise, cervical tenderness, cervical pain, and leukocytosis upon admission. Cervical involvement ranged from C-2 to C-7. All patients underwent laminectomy with durotomy and drainage. The authors recommend prompt surgical decompressive laminectomy, copious irrigation, and drainage, followed with appropriate adjunctive antibiotic therapy for treatment of these patients.
The Massachusetts General Hospital
Authors: Barker Fred G.
Published: May 2009

✓ The early history of the Massachusetts General Hospital (MGH) is reviewed with emphasis on the development of neurological surgery. The hospital opened in 1823. Early trephinations were performed by Dr. John Collins Warren and others for treatment of trauma and epilepsy. In the 1880's, interest in brain surgery increased, and Dr. John Elliot performed several trephinations for brain tumors, three of which were witnessed by Dr. Harvey Cushing during his years at the MGH as medical student and intern. In 1911, all brain surgery was placed in the hands of Dr. S. J. Mixter. He later shared the assignment with his son, Dr. W. J. Mixter, who described herniation of the intervertebral disc with Dr. J. S. Barr and became the first Chief of the Neurosurgical Service at MGH in 1939.
Extracranial-intracranial saphenous vein bypass for carotid or vertebral artery dissections: a report of six cases
Authors: Morgan Michael K. , Sekhon Lali H. S.
Published: May 2009

✓ The management of carotid or vertebral artery dissections has generally been either conservative (with anticoagulation) or surgical (by proximal ligation or trapping procedures). However, identification and management of those patients with a high risk of stroke recurrence have been difficult. Six patients with carotid or vertebral artery dissections underwent a total of seven surgical procedures involving intracranial interpositional saphenous vein bypass grafts anastomosed distally beyond the point of dissection with trapping of the intermediate diseased section of the artery. It is suggested that this procedure be used in patients who have bilateral carotid or vertebral artery disease, persistent angiographic abnormalities (particularly aneurysms), or recurring ischemic events while undergoing anticoagulation therapy, or in whom anticoagulation is undesirable. This procedure has benefits over current surgical options because of the maintenance of high flow, the avoidance of abnormal watershed areas of flow, and the elimination of the risk of emboli. The procedure is compared to previous techniques of extracranial-intracranial bypass.
Intracellular mechanisms involved in the responses of cerebrovascular smooth-muscle cells to hemoglobin
Authors: Vollrath Bozena A. M. , Weir Bryce K. A. , Macdonald R. Loch , Cook David A.
Published: May 2009

✓ An investigation was undertaken of the mechanism by which oxyhemoglobin and its analog methemoglobin might cause cerebrovascular spasm. The effect of these compounds on the levels of intracellular inositol triphosphate and calcium in cultured primate cerebrovascular smooth-muscle cells and the contractile action of oxyhemoglobin on isolated rings of primate cerebral arteries were also examined. Oxyhemoglobin, but not methemoglobin, produces a transient but highly significant increase in the intracellular levels of inositol triphosphate. Intracellular calcium levels in these cells are increased by thrombin, aluminum tetrafluoride, and oxyhemoglobin, and the sustained elevation in intracellular calcium is prevented by ethyleneglycol tetra-acetic acid and the phospholipase C inhibitor neomycin. Removal of the oxyhemoglobin after as long as 48 hours' incubation with this compound allowed cells to rapidly reduce their intracellular calcium levels to near normal. Oxyhemoglobin produced contractions of isolated rings of both normal and spastic cerebral arteries, although the response of spastic vessels was significantly smaller. This effect was inhibited by neomycin. The addition of neomycin relaxed arteries that were contracted with oxyhemoglobin, 5-hydroxytryptamine, or potassium chloride. It is thus likely that activation of phospholipase C is a critical step in the development of vasospasm, but the transient nature of the response to inositol triphosphate suggests that the sustained contraction may arise from other phospholipase C-dependent mechanisms.
Biodegradable polymers for controlled delivery of chemotherapy with and without radiation therapy in the monkey brain
Authors: Brem Henry , Tamargo Rafael J. , Olivi Alessandro , Pinn Michael , Weingart Jon D. , Wharam Moody , Epstein Jonathan I.
Published: May 2009

✓ Sustained drug delivery by biodegradable polymer devices can increase the therapeutic efficacy of drugs by producing high local tissue concentrations over extended periods of time. It has been shown previously that implantation of controlled-release polymers impregnated with the nitrosourea carmustine (BCNU) extended the period of survival in rats bearing the 9L glioma compared with similar rats treated with systemically administered BCNU. This study evaluated the effect on the monkey brain of interstitial delivery of BCNU by the biodegradable polyanhydride copolymer poly[bis(p-carboxyphenoxy)propane]anhydride (PCPP) and sebacic acid (SA) in a 20:80 formulation (PCPP:SA). The effect of combining interstitial BCNU with radiation therapy was also evaluated. Eighteen male cynomologus monkeys were randomly assigned to one of four groups: a control group; a group with implantation of empty polymer; a group with implantation of BCNU-loaded polymer; and a group with implantation of empty polymer in the right hemisphere and BCNU-loaded polymer in the left hemisphere, followed by irradiation. The effects were evaluated radiologically and histologically at specified times. A local reaction by the brain to the polymer was found, which was greater when the polymer contained BCNU. Local cerebral edema was observed radiographically on postoperative Day 14 and had resolved by Day 72. Histologically, a subacute cellular inflammatory response was seen on postoperative Day 16, which had changed to a chronic inflammatory response by Day 72. In the group with radiation therapy administered to the hemisphere bearing BCNU-loaded polymer, only localized pathological changes were detected. In all animals, brain distant from the polymer implantation site was normal. No neurological or general deleterious effects were seen in any of the animals. It is concluded that the interstitial delivery of BCNU by the polyanhydride polymer PCPP:SA is safe in the primate brain and that concomitant radiation therapy did not lead to any adverse effects. These experimental findings are important to an understanding of the clinical effects of PCPP:SA implants in treating brain diseases.
Mit Initialfemeln zum Plenterwald (Essay) | The creation of selection forest using initial femel cut (essay)
Authors: Kynast Rudi
Published: May 2009

Although selection forests have clear advantages over age-group forests in view of their total growth performance, their net product and their stability, not to mention the sustainability of their beneficial effect, the proportion of this type of forest is insignificantly small in Germany and also in mixed forest in the mountains. It is therefore all the more surprising that scarcely any discernable efforts have been made to increase the proportion of selection forests. For a conversion, an alternative model for the treatment of the stands is adopted, whereby it is no longer the encouragement of the growth to maturity of individual trees in the stand which is aimed for, but rather the transformation of the whole stand to a selection forest using available stand elements and elements created by an early initiation of regeneration.

Based on his experience in the forestry district of Kirchzarten in the Black Forest, Germany, the author describes the procedure for a successful conversion. This is to be started as soon as possible, that is to say when the crown height of the trees is about 18 metres and with corresponding usable dimensions, using small group shelter-wood cuts, a so-called initial femel cut. To get the conversion started it is advisable to remove whole groups of predominantly badly situated and overgrown trees. The stand will be additionally structured later through further interventions at short intervals. In the process, here and there really well situated trees will actually be left to stand solitar y, in other places w hol e self-cont aine d groups will b e created and else where valuabl e mixed s tand elements will be selected for permanent preservation, this in order to create a situation in which there are about 35 overstorey trees per hectare. On the basis of his own cost calculations, the author comes to the conclusion that the conversion is, from a financial point of view, superior compared with the age-group forest in that it brings higher proceeds more quickly and more often.
Zur finanziellen Attraktivität von Dauerwaldwirtschaft und Überführung: eine Literaturanalyse | On the financial attractiveness of continuous cover forest management and transformation: a review
Authors: Knoke Thomas
Published: May 2009

Even after decades of discussion on the economic advantages or disadvantages of a forestry management practice using uneven-aged stands there is still no consistent description of the conditions which make continuous cover forests more economically interesting than forests with an age-class gradation. Based on existing references this paper tries to point out such preconditions. Studies of comparative statics at management unit level are presented; these often reveal a clear advantage of continuous cover forests in Central European circumstances. The greater resistance of a forest with continuous cover to abiotic and biotic damage, together with the possibility of harvesting trees when their individual financial maturity is attained, are important reasons for this result. Studies at stand level on the transformation of even-aged into uneven-aged forests do not always show an advantage for continuous cover forest. Here, it seems to be important whether or not interest rates form the basis for the conclusions, and if so how high these interest rates are, also at what age transformation begins. Earlier and more regular net revenues during the process of stand transformation into continuous cover systems can lead to superior financial results when compared to even-aged silvicultural systems . However, present knowledge is still relatively scarce in what concerns possible differences in logging and overhead costs as well as costs for forest roads in the two silvicultural systems under comparison.
The “Wireless Sensor Networks for City-Wide Ambient Intelligence (WISE-WAI)” Project
Authors: Casari Paolo , Castellani Angelo  P. , Cenedese Angelo , Lora Claudio , Rossi Michele , Schenato Luca , Zorzi Michele
Published: May 2009

This paper gives a detailed technical overview of some of the activities carried out in the context of the “Wireless Sensor networks for city-Wide Ambient Intelligence (WISEWAI)” project, funded by the Cassa di Risparmio di Padova e Rovigo Foundation, Italy. The main aim of the project is to demonstrate the feasibility of large-scale wireless sensor network deployments, whereby tiny objects integrating one or more environmental sensors (humidity, temperature, light intensity), a microcontroller and a wireless transceiver are deployed over a large area, which in this case involves the buildings of the Department of Information Engineering at the University of Padova. We will describe how the network is organized to provide full-scale automated functions, and which services and applications it is configured to provide. These applications include long-term environmental monitoring, alarm event detection and propagation, single-sensor interrogation, localization and tracking of objects, assisted navigation, as well as fast data dissemination services to be used, e.g., to rapidly re-program all sensors over-the-air. The organization of such a large testbed requires notable efforts in terms of communication protocols and strategies, whose design must pursue scalability, energy efficiency (while sensors are connected through USB cables for logging and debugging purposes, most of them will be battery-operated), as well as the capability to support applications with diverse requirements. These efforts, the description of a subset of the results obtained so far, and of the final objectives to be met are the scope of the present paper.
An Examination of Work Instability, Functional Impairment, and Disease Activity in Employed Patients with Rheumatoid Arthritis
Authors: MACEDO ALYSSA , OAKLEY STEPHEN , GULLICK NICOLA , KIRKHAM BRUCE
Published: May 2009

Objective.

To evaluate the relationship between the Disease Activity Score 28-joint count (DAS28), Health Assessment Questionnaire (HAQ), and Rheumatoid Arthritis-Work Instability Scale (RAWIS); and to define thresholds for clinical assessments associated with moderate to high RA-WIS.

Methods.

Employed patients with RA were evaluated using DAS28, HAQ, and RA-WIS during routine clinics. Relationships between these assessments were evaluated by simple correlation. Multiple linear regression modeling was performed using RA-WIS as an outcome variable and HAQ, DAS28, age, sex, occupation, and disease duration as input variables. Receiver-operating characteristic curves were then formulated to determine optimal DAS28, and HAQ cutoff points for RA-WIS ≥ 10, along with the odds ratio (OR).

Results.

Ninety patients with RA completed the RA-WIS, which was moderately correlated with DAS28 (r =0.53) and HAQ (r = 0.66). Fifty-four percent of RA-WIS was explained by DAS28 (p = 0.002), HAQ (p = 0.001), and sex (p = 0.04). A DAS28 of 3.81 and HAQ of 0.55 were clinically important thresholds. High DAS28 and HAQ were associated with high RA-WIS (ORDAS 14.17, ORHAQ 25.13, ORDAS+HAQ 29.9).

Conclusion

Functional impairment and disease activity significantly and independently contributed to patient-perceived work instability risk.
Investigating the Validity of the Minimal Disease Activity State for Patients with Rheumatoid Arthritis Treated with Abatacept
Authors: WELLS GEORGE A. , BOERS MAARTEN , LI TRACY , TUGWELL PETER S.
Published: May 2009

Objective.

To validate the definitions of minimal disease activity (MDA) in patients with rheumatoid arthritis (RA) and to compare abatacept to control with respect to patients attaining a state of MDA.

Methods.

Two randomized controlled trials comparing abatacept to control in patients with RA were considered: ATTAIN and AIM. Core set measures, Disease Activity Score 28-joint count (DAS28), and, for AIM, radiographic scores were available. The core set and DAS-based definitions for MDA were calculated and the number of patients in the treatment groups meeting the definitions was compared to determine sensitivity of the criteria to treatment differences and patient severity. The number of times achieving MDA was compared to the change in Health Assessment Questionnaire (HAQ), and for the AIM study compared to change in radiographic scores.

Results.

For both definitions of MDA, the change in radiographic scores showed a continual decrease in progression the more often a patient was in MDA. The change in HAQ, for both studies, showed a similar consistent improvement — the longer a patient was in MDA, then the better the HAQ score. Significantly more patients in the abatacept group met the core set and DAS-based definition of MDA than in the control group.

Conclusion.

The presence and persistence of MDA was associated with slowing of radiographic progression and improvement in the HAQ, providing support for discriminative and predictive validity of the measure. The MDA results were consistent with other efficacy analyses indicating a treatment advantage for abatacept.
Cartilage and Bone Biomarkers in Rheumatoid Arthritis: Prediction of 10-year Radiographic Progression
Authors: SYVERSEN SILJE W. , GOLL GURO L. , van der HEIJDE DÉSIRÉE , LANDEWÉ ROBERT , GAARDER PER IVAR , ØDEGÅRD SIGRID , HAAVARDSHOLM ESPEN A. , KVIEN TORE K.
Published: May 2009

Objective.

As current predictors of joint destruction have low specificity, serological biomarkers reflecting bone and cartilage destruction have been proposed as tools in assessing prognosis of rheumatoid arthritis (RA). We examined whether serum concentrations of a panel of biomarkers could predict radiographic progression in patients with RA.

Methods.

A cohort of 238 patients with RA was followed longitudinally for 10 years with collection of clinical data and serum samples. These analyses focus on the 136 patients with radiographs of the hands available at baseline and at 5 and/or 10 years. Radiographs were scored according to the van der Heijde-modified Sharp score (SHS). Baseline sera were analyzed for receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), human cartilage glycoprotein-39 (YKL-40), C2C, collagen cross-linked C-telopeptide (CTX-I), and cartilage oligomeric matrix protein (COMP). Multivariate linear and logistic regression analyses were used to identify predictors of radiographic progression.

Results.

Baseline CTX-I levels were higher in progressors [0.41 ng/ml (interquartile range 0.31–0.75)] than in nonprogressors [0.32 ng/ml (IQR 0.21–0.49)], and were independently associated with 10-year change in radiographic damage score [ß = 16.4 (IQR 5.7–27.1)]. We found no association between radiographic progression and baseline serum levels of RANKL, OPG, C2C, YKL-40, or COMP.

Conclusion.

This longterm followup study of patients with RA indicates a relationship between elevated CTX-I levels in serum and subsequent joint destruction. This association was, however, weak, and our study does not support that serum CTX-I or any of the other tested biomarkers will serve as more useful prognostic markers than current predictors such as anti-cyclic citrullinated peptide, radiographic damage early in the disease course, and signs of inflammation.
Time Trends in Epidemiology and Characteristics of Psoriatic Arthritis Over 3 Decades: A Population-based Study
Authors: WILSON FLORANNE C. , ICEN MURAT , CROWSON CYNTHIA S. , McEVOY MARIAN T. , GABRIEL SHERINE E. , KREMERS HILAL MARADIT
Published: May 2009

Objective.

To determine time trends in incidence, prevalence, and clinical characteristics of psoriatic arthritis (PsA) over a 30-year period.

Methods.

We identified a population-based incidence cohort of subjects aged 18 years or over who fulfilled ClASsification of Psoriatic ARthritis (CASPAR) criteria for PsA between January 1, 1970, and December 31, 1999, in Olmsted County, Minnesota, USA. PsA incidence date was defined as the diagnosis date of those who fulfilled CASPAR criteria. Age- and sex-specific incidence rates were estimated and age- and sex-adjusted to the 2000 US White population.

Results.

The PsA incidence cohort comprised 147 adult subjects with a mean age of 42.7 years, and 61% were men. The overall age- and sex-adjusted annual incidence of PsA per 100,000 was 7.2 [95% confidence interval (CI) 6.0, 8.4] with a higher incidence in men (9.1, 95% CI 7.1, 11.0) than women (5.4, 95% CI 4.0, 6.9). The age- and sex-adjusted incidence of PsA per 100,000 increased from 3.6 (95% CI 2.0, 5.2) between 1970 and 1979 to 9.8 (95% CI 7.7, 11.9) between 1990 and 2000 (p for trend < 0.001). The point prevalence per 100,000 was 158 (95% CI 132, 185) in 2000, with a higher prevalence in men (193, 95% CI 150, 237) than women (127, 95% CI 94, 160). At incidence, most PsA subjects had oligoarticular involvement (49%) with enthesopathy (29%).

Conclusion.

The incidence of PsA has been rising over 30 years in men and women. Reasons for the increase are unknown, but may be related to a true change in incidence or greater physician awareness of the diagnosis.
Redes y mecanismos de interdependencia. Desarrollos teóricos más allá de los modelos de acción racional
Authors: González-Bailón Sandra
Published: May 2009

Existe interdependencia cuando las acciones de unos individuos influyen en las decisiones (y posteriores acciones) de otros individuos. Este artículo sostiene que las redes sociales definen la estructura de ese espacio de influencia y desatan una serie de mecanismos de los que la teoría de la elección racional no puede dar cuenta. Las redes sociales abren acceso a las ideas y acciones de otros individuos, y esta exposición determina la satisfacción de umbrales, el tempo con en el que se llevan a cabo las acciones y la emergencia de procesos de contagio, cascadas de información y epidemias. Este artículo defiende que la teoría de la elección racional no ofrece las herramientas necesarias para modelizar tales procesos si no se inserta en una teoría general de redes. Éste es especialmente el caso en unos momentos en los que la interdependencia de individuos está adquiriendo, al amparo de las nuevas tecnologías, mayor relevancia empírica.