bluuebunny/crossref_metadata_2025_split huggingface dataset:
The predictive value of catecholamines in assessing outcome in traumatic brain injury
Authors: Woolf Paul D. , Hamill Robert W. , Lee Louyse A. , Cox Christopher , McDonald Joseph V. 
Published: May 2009

✓ Because of the central role of the sympathetic nervous system in mediating the stress response, plasma norepinephrine (NE), epinephrine (E), and dopamine (DA) levels were measured in 61 traumatically brain-injured patients to determine whether catecholamine (CA) levels obtained within 48 hours after injury provide reliable prognostic markers of outcome. Patient outcome was determined at 1 week using the Glasgow Coma Scale (GCS) and at the time of discharge using the Glasgow Outcome Scale (GOS). Levels of NE, E, and DA correlated highly with the admission GCS score (NE: r = 0.58, p < 0.0001; E: r = 0.46, p < 0.0025; DA: r = 0.27, p < 0.04). Moreover, in the 21 patients with GCS scores of 3 or 4 on admission, NE levels predicted outcome at 1 week. All six patients with NE levels less than 900 pg/ml (normal level less than 447 pg/ml) improved to GCS scores of greater than 11, while 12 of 15 with NE values greater than 900 pg/ml remained with GCS scores of 3 to 6 or died. Levels of E and DA were not as useful. Catecholamine levels also increased significantly as the GOS score worsened. Levels of NE and E were significantly higher in patients who died or remained persistently vegetative than in those with better outcomes. In the 54 patients who survived beyond 1 week, significant correlations were present between the length of hospitalization and NE (r = 0.71, p < 0.0001) and E (r = 0.61, p < 0.0001) levels. Concentrations of NE (r = 0.61, p < 0.0004) and E (r = 0.48, p < 0.01) were also highly correlated with the duration of ventilatory assistance. Analysis of the interactions of CA levels and GCS scores, duration of ventilatory assistance, and length of hospitalization revealed that the CA's either enhanced the reliability of the GCS score or were independent predictors of outcome.
Thus, these findings indicate that alterations in circulating CA levels reflect the severity of the neurological insult and provide support for the use of CA measurements as a physiological marker of patient outcome in both the acute and chronic phases of traumatic brain injury.
Effect of subarachnoid hemorrhage on endothelium-dependent vasodilation
Authors: Nakagomi Tadayoshi , Kassell Neal F. , Sasaki Tomio , Fujiwara Shigeru , Lehman R. Michael , Johshita Hiroo , Nazar Gregory B. , Torner James C. 
Published: May 2009

✓ The effect of subarachnoid hemorrhage (SAH) on endothelium-dependent vasodilation of the isolated rabbit basilar artery was examined using an isometric tension recording method. The SAH was induced by injecting 5 ml of fresh arterial blood into the cisterna magna. Sixty-two rabbits were separated into four groups according to the timing of sacrifice: control rabbits, and operated rabbits sacrificed on Days 2, 4, and 6 after SAH. Acetylcholine (ACh) (10−7 M to 10−4 M) and adenosine triphosphate (ATP) (10−7 M to 10−4 M) were used to evoke dose-dependent vasodilation of isolated arterial rings previously contracted by 10−6 M serotonin (5-HT). There were no significant differences in the vasodilatory response to ACh among these four groups. Relaxation to approximately 84% of the initial contractile tone occurred with 10−4 M ACh. On the other hand, the vasodilatory response to ATP was suppressed in the animals sacrificed 2 days after SAH; the relaxation of this group was approximately 52% at 10−4 M ATP, compared to a relaxation of 87% observed in the other groups of animals. One of the major causes of the impairment of endothelium-dependent vasodilation seems to be an inhibition of the production of endothelium-derived relaxing factor by endothelial cells.
After the relaxation studies, the dose-response curves for 5-HT were obtained. Serotonin caused significantly more contraction in the animals sacrificed 2 days after SAH than in the other groups. The present experiments suggest that impairment of the endothelium-dependent vasodilation following SAH, together with the potentiation of the contractile response to vasoactive agents in cerebral arteries, may play an important role in the pathogenesis of vasospasm.
Surgical management of large AVM's by staged embolization and operative excision
Authors: Spetzler Robert F. , Martin Neil A. , Carter L. Philip , Flom Richard A. , Raudzens Peter A. , Wilkinson Elizabeth 
Published: May 2009

✓ A series of 20 patients with giant arteriovenous malformations (AVM's) managed with staged embolization and surgical resection is presented. Complete excision was accomplished in 18 of these patients. There were no deaths and only three complications, of which one was disabling. Further evidence for the presence of low perfusion surrounding the AVM, emphasizing the risk of normal perfusion pressure breakthrough, is provided by cortical perfusion pressure, cortical cerebral blood flow (CBF), and stable xenon computerized tomography CBF measurements.The staged approach to giant AVM management is a proposed method to render AVM's that were previously considered inoperable or marginally operable into totally excisable lesions, while maintaining an acceptable level of morbidity and mortality.
Effect of barbiturate coma on glucose utilization in normal brain versus gliomas
Authors: Blacklock J. Bob , Oldfield Edward H. , Di Chiro Giovanni , Tran Dung , Theodore William , Wright Donald C. , Larson Steven M. 
Published: May 2009

✓ Glucose utilization by normal and neoplastic cerebral tissue can be measured in humans using positron emission tomography (PET) with fluorine-18-labeled 2-deoxy-D-glucose (FDG). Malignant gliomas are known to exhibit hypermetabolic glucose consumption compared to normal brain. Barbiturate-sensitive cerebral glucose utilization is coupled to neuronal activity, and lesions lacking neuronal activity should be relatively insensitive to barbiturate suppression of glucose utilization. In a study to examine this phenomenon, three patients with cerebral gliomas underwent FDG-PET while awake and during deep barbiturate coma. Cerebral glucose utilization was measured in normal brain, tumor, and a homologous, non-neoplastic control site in the contralateral hemisphere. A glucose utilization ratio for tumor/control tissue was calculated.
The mean reduction of glucose utilization during barbiturate coma was: gray matter 67%, white matter 47%, basal ganglia 66%, thalamus 57%, cerebellar cortex 55%, tumor 32%, and the contralateral control site 64%. The mean tumor glucose utilization ratio was 1.48:1 in the awake state and 2.69:1 during barbiturate coma. The changes in gray matter, basal ganglia, thalamus, cerebellar cortex, and tumor/control tissue ratio were significant (p < 0.05). In one patient, deep tumor invasion not evident on computerized tomography, magnetic resonance imaging, or baseline FDG-PET was apparent during barbiturate-enhanced FDG-PET scanning.
The study findings suggest that gliomas resist suppression of glucose utilization by barbiturates; this supports the hypothesis that barbiturates reduce neuronal metabolism by blocking synaptic activity. This differential effect on normal brain and gliomas enhances the capability to assess the extent of neoplastic tissue in brain and may represent the basis for novel therapeutic strategies.
Cervical spine stenosis secondary to ossification of the posterior longitudinal ligament
Authors: Harsh Griffith R. , Sypert George W. , Weinstein Philip R. , Ross Donald A. , Wilson Charles B. 
Published: May 2009

✓ Ossification of the posterior longitudinal ligament (OPLL) is a well-documented cause of cervical spine stenosis and myelopathy among Japanese patients. Reports of OPLL in North Americans are rare. Choices of diagnostic method and treatment for this entity remain controversial. The authors report the results of management of 20 patients in the United States with symptomatic OPLL of the cervical spine. These represented 10% to 20% of patients operated on over the last 3 years for myelopathy secondary to structural spinal compression. Most of these OPLL patients were Caucasian (60%), male (male:female 4:1), and middle-aged (median age 47.5 years). Six had previously undergone laminectomy or discectomy. Cervical roentgenograms and standard myelography occasionally suggested the diagnosis. Axial computerized tomography (CT) metrizamide myelography with small interslice intervals proved invaluable for diagnosis and operative planning. Magnetic resonance imaging was not necessary for diagnosis. Retrovertebral calcification extended over one to five bodies (mean 2.75). The mass ranged in size from 5 to 16 mm in anteroposterior diameter and reduced the residual canal diameter to a mean (± standard deviation) caliber of 9.42 ± 2.41 mm (mean narrowing ratio 0.44 ± 0.12).
Anterior cervical decompression by medial corpectomy and discectomy with fusion uniformly reduced preoperative myelopathy. Complications were limited to transient neurological deterioration in two patients, recurrent laryngeal nerve palsy in one, and halo device pin site infections in two. At a mean postoperative interval of 15 months, improvement was seen in each category of deficit: extremity weakness, hypesthesia, hypertonia, and urinary dysfunction. All fusions produced solid unions.
It is concluded that OPLL of the cervical spine is an unexpectedly prevalent cause of myelopathy among patients treated in the United States. Thin-section axial CT metrizamide myelography with small interslice intervals is essential for the investigation of patients who may have OPLL. Anterior decompression and stabilization by medial corpectomy, discectomy, removal of the calcified mass, and fusion is a safe and effective method of treatment.
Recombinant human tissue-type plasminogen activator therapy in acute thromboembolic stroke
Authors: Papadopoulos Stephen M. , Chandler William F. , Salamat M. Shahriar , Topol Eric J. , Sackellares J. Chris 
Published: May 2009

✓ Systemic fibrinolytic therapy for acute stroke is no longer recommended because of resulting systemic fibrinolysis and the risk of intracerebral hemorrhage. Human tissue-type plasminogen activator (TPA) is a native enzyme that converts plasminogen to plasmin with subsequent clot lysis. The affinity for plasminogen is increased several-fold when the substrate is bound to fibrin. At appropriate dosage, “clot-specific” throm-bolysis may be achieved at the surface of the thrombus without creating systemic fibrinolysis.
The authors designed a study to evaluate the effect of intravenous TPA administered 2 hours after acute thromboembolic stroke in rats. This time course was chosen to simulate an analogous clinical situation. Middle cerebral artery embolic stroke was caused by intracarotid injection of 0.025 cc of human blood clot in 16 rats. Regional cerebral blood flow, measured by the hydfogen clearance technique, and electroencephalographic (EEG) recordings were obtained every 30 minutes for 5 hours after thromboembolism. Eight rats received a 1-hour infusion of intravenous TPA (1.5 mg/kg) 2 hours after injection of emboli. Ipsilateral blood flow increased significantly within 30 minutes after intravenous TPA and reached preembolic levels within 60 minutes. Blood flow did not improve in the eight control rats throughout the experiment. Power spectral analysis of the EEG recordings showed improvement in the treated group compared to the control group. Postmortem angiography revealed proximal middle cerebral artery occlusion in control animals and patent middle cerebral arteries in TPA-treated animals. Serum fibrinogen and fibrin split products were unchanged in both groups, indicating the absence of systemic fibrinolysis. There were no intracerebral hemorrhages.
It is concluded that, in this rat model, TPA increases blood flow with subsequent improvement in the EEG recording after thromboembolic stroke without evidence of systemic fibrinolysis. Intravenous TPA may be useful in the treatment of acute stroke in man.
Quantitative study of microvessel ultrastructure in human peritumoral brain tissue
Authors: Stewart Patricia A. , Hayakawa Kay , Farrell Catherine L. , Del Maestro Rolando F. 
Published: May 2009

✓ The form and function of blood vessels are determined by the cells that constitute their microenvironment. Brain tissue around tumors contains varying numbers of tumor cells that could influence local capillaries to lose their blood-brain barrier (BBB), as they do in the tumor itself. Microvascular permeability cannot be measured directly in humans but can be inferred from a knowledge of vessel ultrastructure. The authors have examined the vascular ultrastructure associated with the BBB in human peritumoral brain tissue for evidence of BBB compromise and to correlate BBB features with the cellular components of the vessel microenvironment.
Light microscopic examination of brain tissue samples in patients with primary brain tumors showed that the tissue lying beyond the visible edge of the tumor ranged from essentially normal to grossly infiltrated with tumor cells. Although some of the vessels were structurally normal, the microvessels as a group had elongated junctional clefts (unfused regions) and an increase in the density of endothelial vesicles. Furthermore, the cleft index (the percentage of the junctional profile that is unfused) varied directly with the local cell density. A subpopulation of vessels enveloped by a layer of tumor cells was grossly abnormal. However, vessels that were not immediately invested by tumor cells also showed some abnormalities. It is concluded that tumor cells infiltrating peritumoral brain tissue cause blood vessels to take on some of the structural characteristics of leaky vessels. Since direct contact is not required, and since the degree of abnormality correlates with the number of tumor cells in the environment, the authors suggest that this inductive influence is exerted over a distance and is dependent on the concentration of the inducing factors.
Spinal arteriovenous malformations: a comparison of dural arteriovenous fistulas and intradural AVM's in 81 patients
Authors: Rosenblum Bruce , Oldfield Edward H. , Doppman John L. , Di Chiro Giovanni 
Published: May 2009

✓ The medical records and arteriograms of 81 patients with spinal arteriovenous malformations (AVM's) were reviewed, and the vascular lesions were classified as dural arteriovenous (AV) fistulas or intradural AVM's. Intradural AVM's were further classified as intramedullary AVM's (juvenile and glomus types) and direct AV fistulas, which were extramedullary or intramedullary in location. Dural AV fistulas were defined as being supplied by a dural artery and draining into spinal veins via an AV shunt in the intervertebral foramen. Intramedullary AVM's were defined as having the AV shunt contained at least partially within the cord or pia and receiving arterial supply by medullary arteries.
Of the 81 patients, 27 (33%) had dural AV fistulas and 54 (67%) had intradural AVM's. Several dissimilarities in clinical and radiographic findings of the two subgroups were evident. The patients with intramedullary AVM's were younger; the age at onset of symptoms averaged 27 years compared to 49 years for dural AV fistulas. The most common initial symptom associated with dural AV fistulas was steadily progressive paresis, whereas hemorrhage was the most common presenting symptom in cases of intramedullary lesions. No patients with dural AV fistulas had subarachnoid hemorrhage. Activity exacerbated symptoms more frequently in patients with dural lesions. Associated vascular anomalies occurred only in cases of intradural AVM's. In 96% of the dural lesions the AV nidus was in the low thoracic or lumbar region; in only 15% did the intercostal or lumbar arteries supplying the AVM also provide a medullary artery which supplied the spinal cord. In contrast, most intradural AVM's (84%) were in the cervical or thoracic segments of the spinal cord and all of them were supplied by medullary arteries. Transit of contrast medium through the intradural AVM's was rapid in 80% of cases, suggesting high-flow lesions. Forty-four percent of the patients with AVM's of the spinal cord had associated saccular arterial or venous spinal aneurysms. No dural AV fistulas displayed these characteristics. A good outcome occurred in 88% of patients with dural AV fistulas after nidus obliteration, while 49% of patients with intramedullary AVM's did well after surgery or embolization.
These findings suggest that dural and intradural AVM's differ in etiology (acquired vs. congenital) and that they have different pathophysiology, radiographic findings, clinical presentation, and response to treatment.
Gliomas of the optic nerve or chiasm
Authors: Alvord Ellsworth C. , Lofton Steven 
Published: May 2009

✓ A review of the literature revealed 623 cases of optic gliomas with sufficient information to permit actuarial (life-table) analysis concerning the prognosis of this disease by the patients' age, tumor site, treatment, and presence of concomitant neurofibromatosis or extension into the hypothalamus or ventricle. All of these factors are important. The development of mathematical models led to the conclusion that these tumors, generally regarded histologically as low-grade astrocytomas, actually have a very wide but continuous range of growth rates. Some grow rapidly enough to be explained by simple exponential doubling at a constant rate, but most behave as though their growth decelerates. Decelerating growth rates make comparisons of various groups of patients difficult. No support is found for the classical hypothesis that some may be hamartomas.Inadequately treated gliomas of the optic nerve or chiasm bear about the same poor prognosis. However, tumors of the optic nerve (intracranial as well as intraorbital) have an excellent prognosis following complete surgical excision and only a slightly poorer prognosis following irradiation. About 5% of optic nerve gliomas recur in the chiasm following “complete” intraorbital excision. Patients with neurofibromatosis have about twice the recurrence rate following complete excision of an intraorbital glioma. Optic chiasmal gliomas appear to respond to irradiation with doses above 4500 rads. Patients with neurofibromatosis have about the same prognosis as patients without neurofibromatosis following irradiation of a chiasmal glioma.
Symptomatic low intracranial pressure in shunted hydrocephalus
Authors: Foltz Eldon L. , Blanks Jeff P. 
Published: May 2009

✓ Fourteen patients with ventricular cerebrospinal fluid shunts in place for chronic hydrocephalus presented with a history and neurological deficits usually associated with high intracranial pressure (ICP) caused by an obstructed shunt system. However, the symptoms were characteristically present when the patient was upright and active, and were usually relieved by lying down. The symptoms of intermittent headache, nausea, emesis, lethargy, and diplopia were associated with paresis of upward gaze or minimal strabismus. Measurement of ICP showed unexpected dramatically low levels with a marked drop in pressure when the patient was in the upright position, whereas ICP was near normal when the patient was supine. The low ICP was corrected by insertion of a high-pressure Flo-Control valve into the shunt system already in place. Postoperatively, the immediate clinical improvement and more normal ICP measurements were striking.
The important clinical finding in this group of patients was the presence of disabling symptoms which occurred when the patients were up and active and which were relieved by lying down. Measurements of ICP with the patient in the supine and then in the upright position were critical in establishing an accurate diagnosis of symptomatic low ICP in these hydrocephalic patients with indwelling shunts. With the patient in the Trendelenburg position, ICP showed a marked increase, as expected; in some patients this position was prescribed as treatment for several days before surgery.
Clinical, radiological, and pathological spectrum of angiographically occult intracranial vascular malformations
Authors: Lobato Ramiro D. , Perez Carlos , Rivas Juan J. , Cordobes Francisco 
Published: May 2009

✓ The clinical, radiological, and histopathological features of 21 cases of angiographically occult intracranial vascular malformations (AOIVM's) are analyzed, and a review of 241 additional appropriately documented, histologically verified cases collected from the literature is presented. In all, there were 115 (43.8%) arteriovenous malformations, 82 (31.2%) cavernous angiomas, 26 (9.9%) venous angiomas, 10 (3.8%) cases of capillary telangiectasis, and 29 (11%) mixed or unclassified angiomas. The result of the analysis shows that there are no essential differences in the patterns of clinical presentation, the computerized tomography (CT) appearance, or the surgical prognosis among these pathological types of vascular malformations. Certain histological features common to all AOIVM's (such as the small caliber, the more or less complete thrombosis of the malformed vessels, and the changes induced in the surrounding brain tissue by repeated microhemorrhages) seem to determine the biological behavior of the anomaly rather than the predominant type of vessel involved. Thus, subdivision of AOIVM's into the four classical pathological types has little practical value.
Most AOIVM's are visualized by the CT scan and show a rather typical appearance. Surgical removal, which prevents rebleeding and ameliorates or suppresses seizure activity, is usually easy to perform and represents the treatment of choice for patients with clinically symptomatic AOIVM's.
Bilateral trigeminal neuralgia: a 14-year experience with microvascular decompression
Authors: Pollack Ian F. , Jannetta Peter J. , Bissonette David J. 
Published: May 2009

✓ Thirty-five patients with trigeminal neuralgia (TN) bilaterally underwent posterior fossa microvascular decompression (MVD) between 1971 and 1984. They comprised 5.0% of a larger series of 699 patients with TN who underwent MVD during that interval. Compared to the subgroup of 664 patients with only unilateral symptoms, the population with bilateral TN included a greater percentage of females (74% vs. 58%, p < 0.1), a higher rate of “familial” TN (17% vs. 4.1%, p < 0.001), and an increased incidence of additional cranial nerve dysfunction (17% vs. 6.6%, p < 0.05) and hypertension (34% vs. 19%, p < 0.05).
Of the 35 patients with bilateral TN, 10 underwent bilateral MVD (22 procedures) and 25 underwent unilateral MVD (30 procedures). In the latter patients, pain on the nonoperative side was well controlled with medication alone or had previously been treated by ablative procedures. Good or excellent pain control was achieved after one MVD was performed in 40 of the 45 sides treated (89%), and was maintained 1, 5, and 10 years after surgery in 82%, 66%, and 60%, respectively, based on life-table analysis. Six of 10 patients with recurrent symptoms underwent repeat unilateral MVD. Good or excellent long-term pain control was maintained in all six. With these repeat procedures included, symptom control at 1, 5, and 10 years after initial surgery was maintained in 87%, 78%, and 78% of the treated sides, respectively. Overall, 26 of 35 patients (74%) maintained good or excellent pain relief throughout the duration of the study (mean follow-up period 75 months) without resumption of regular medication usage. Although preoperative neurological deficits resulting from previous ablative procedures were seen in the majority of patients before MVD, no patient developed new major trigeminal sensory loss or masseter weakness after MVD. Operative mortality was zero. The results indicate that posterior fossa MVD is an effective and relatively safe treatment for the majority of patients with bilateral “idiopathic” TN, avoiding the risks of bilateral trigeminal nerve injury seen with other approaches.