Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis

BACKGROUND

Endarterectomy reduces risk of stroke in certain patients with recently symptomatic internal carotid stenosis. However, investigators have made different recommendations about the degree of stenosis above which surgery is effective, partly because of differences between trials in the methods of measurement of stenosis. To accurately assess the overall effect of surgery, and to increase power for secondary analyses, we pooled trial data and reassessed carotid angiograms.

METHODS

We pooled data from the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial, and Veterans Affairs trial 309 from the original electronic data files. Outcome events were re-defined, if necessary, to achieve comparability. Pre-randomisation carotid angiograms from ECST were re-measured by the method used in the other two trials.

RESULTS

Risks of main outcomes in both treatment groups and effects of surgery did not differ between trials. Data for 6092 patients, with 35000 patient-years of follow-up, were therefore pooled. Surgery increased the 5-year risk of ipsilateral ischaemic stroke in patients with less than 30% stenosis (n=1746, absolute risk reduction -2.2%, p=0.05), had no effect in patients with 30-49% stenosis (1429, 3.2%, p=0.6), was of marginal benefit in those with 50-69% stenosis (1549, 4.6%, p=0.04), and was highly beneficial in those with 70% stenosis or greater without near-occlusion (1095, 16.0%, p<0.001). There was a trend towards benefit from surgery in patients with near-occlusion at 2 years' follow-up (262, 5.6%, p=0.19), but no benefit at 5 years (-1.7%, p=0.9).

INTERPRETATION

Re-analysis of the trials with the same measurements and definitions yielded highly consistent results. Surgery is of some benefit for patients with 50-69% symptomatic stenosis, and highly beneficial for those with 70% symptomatic stenosis or greater but without near-occlusion. Benefit in patients with carotid near-occlusion is marginal in the short-term and uncertain in the long-term.

Long-term durability of carotid endarterectomy for symptomatic stenosis and risk factors for late postoperative stroke

BACKGROUND AND PURPOSE

Carotid endarterectomy (CEA) reduces the risk of stroke ipsilateral to recently symptomatic severe carotid stenosis. Other techniques such as percutaneous transluminal angioplasty with stenting are currently being compared with CEA. Thus far, case series and several small, randomized, controlled trials of CEA versus percutaneous transluminal angioplasty (with and without stenting) have focused primarily on the 30-day procedural risks of stroke and death. However, long-term durability is also important. To determine the long-term risk of stroke after CEA and to identify risk factors, we studied patients in the European Carotid Study Trial (ECST), the largest published cohort with long-term follow-up by physicians after CEA.

METHODS

Risks of ipsilateral carotid territory ischemic stroke were calculated by Kaplan-Meier analysis starting on the 30th day after CEA in 1728 patients who underwent trial surgery. Risk factors were determined by Cox regression. For comparison, we also determined the "background" risk of stroke on medical treatment in the ECST in the territory of 558 previously asymptomatic contralateral carotid arteries with <30% angiographic stenosis (ECST method) at randomization.

RESULTS

The risks of disabling ipsilateral ischemic stroke and any ipsilateral ischemic stroke were constant after CEA, reaching 4.4% [95% confidence interval (CI), 3.0 to 5.8] and 9.7% (95% CI, 7.6 to 11.7), respectively, by 10 years. The equivalent ischemic stroke risks distal to contralateral <30% asymptomatic carotid stenoses were 1.9% (95% CI, 0.8 to 3.2) and 4.5% (95% CI, 1.5 to 7.4). Presentation with cerebral symptoms, diabetes, elevated systolic blood pressure, smoking, male sex, increasing age, and a lesser severity of preoperative stenosis were associated with an increased risk of late stroke after CEA, but plaque morphology and patch grafting were not.

CONCLUSIONS

Although the risk of late ipsilateral ischemic stroke after CEA for symptomatic stenosis is approximately double the background risk in the territory of <30% asymptomatic stenosis, it is still only approximately 1% per year and remains low for at least 10 years after CEA. This is the standard against which alternative treatments should be judged. Several risk factors may be useful in identifying patients at particularly high risk of late postoperative stroke.

Serum S-100beta as a possible marker of blood-brain barrier disruption

Two brain-specific proteins, S-100beta and neuron-specific enolase (NSE), are released systemically after cerebral lesions, but S-100beta levels sometimes rise in the absence of neuronal damage. We hypothesized that S-100beta is a marker of blood-brain barrier (BBB) leakage rather than of neuronal damage. We measured both proteins in the plasma of patients undergoing iatrogenic BBB disruption with mannitol, followed by chemotherapy. Serum S-100beta increased significantly after mannitol infusion (P<0.05) while NSE did not. This suggests that S-100beta is an early marker of BBB opening that is not necessarily related to neuronal damage.

Overexpression of multiple drug resistance genes in endothelial cells from patients with refractory epilepsy

PURPOSE

It has been suggested that altered drug permeability across the blood-brain barrier (BBB) may be involved in pharmacoresistance to antiepileptic drugs (AEDs). To test this hypothesis further, we measured multiple drug resistance (MDR) gene expression in endothelial cells (ECs) isolated from temporal lobe blood vessels of patients with refractory epilepsy. ECs from umbilical cord or temporal lobe vessels obtained from aneurysm surgeries were used as comparison tissue.

METHODS

cDNA arrays were used to determine MDR expression. MDR protein (MRP1) immunocytochemistry and Western blot analysis were used to confirm cDNA array data.

RESULTS

We found overexpression of selected MDR and significantly higher P-glycoprotein levels in "epileptic" versus "control" ECs. Specifically, MDR1, cMRP/MRP2, and MRP5 were upregulated in epileptic tissue, whereas Pgp3/MDR3 levels were comparable to those measured in comparison tissue. The gene encoding cisplatin resistance--associated protein (hCRA-alpha) also was overexpressed in epileptic tissue. Immunocytochemical analysis revealed that MDR1 immunoreactivity was localized primarily in ECs; MRP1 protein levels also were significantly higher in epileptic tissue.

CONCLUSIONS

Complex MDR expression changes may play a role in AEDs pharmacoresistance by altering the permeability of AEDs across the BBB.

Induction of a senescence-like phenotype in bovine aortic endothelial cells by ionizing radiation

Treatment of confluent monolayers of bovine aortic endothelial cells (BAEC) with gamma rays resulted in the delayed appearance of cells with an enlarged surface area that were morphologically similar to senescent cells. The majority of these cells stained positively for senescence-associated beta-galactosidase (SA-beta-gal), indicating that these cells are biochemically similar to senescent cells. The incidence of the senescence-like phenotype increased with dose (5-15 Gy) and time after irradiation. Cells with a senescence-like phenotype began to appear in the monolayer several days after irradiation. The onset of the appearance of this phenotype was accelerated by subculturing 24 h after irradiation. This acceleration was not entirely due to stimulation of progression through the cell cycle, since a high percentage of the senescent-like cells that appeared after subculture were not labeled with BrdUrd during the period after subculture. Prolonged up-regulation of expression of CDKN1A (also known as p21(CIP1/WAF1)) after irradiation was noted by Western blot analysis, again suggesting a similarity to natural senescence. Phenotypically altered endothelial cells were present in the irradiated monolayers as long as 20 weeks after irradiation, suggesting that a subpopulation of altered endothelial cells that might be functionally deficient could persist in the vasculature of irradiated tissue for a prolonged period after irradiation.

Gamma knife radiosurgery in the management of patients with acromegaly: a review

Although acromegaly is a rare disease, the need for an effective treatment that is able to induce biochemical cure is an extremely important issue. Unsuccessfully treated acromegaly is associated with increased morbidity and an age-corrected mortality so that early and aggressive therapy to normalize hormonal levels should be instituted at diagnosis. Ideally, the growth hormone-secreting adenoma should be completely resected, with preservation or subsequent restoration of pituitary function. Patients with recurrence or failure after surgery are treated with a second surgery, medical, radiation treatment, or combined modality treatment. Steotactic radiosurgery with gamma knife allows the delivery of focused radiation in a single session to the pituitary tumor that delivers a more biologically effective dose to the tumor than fractionated radiotherapy. Its use as a primary or adjuvant treatment for acromegalics may be more cost effective than medical treatment in these patients. Although it seems to be very effective in controlling growth and secretion of the growth hormone-secreting pituitary adenomas, there is a chance that some major risks from gamma knife radiosurgery might occur. This article will review the role that gamma knife radiosurgery might have in patients with acromegaly.

Cooling for acute ischemic brain damage (cool aid): an open pilot study of induced hypothermia in acute ischemic stroke

BACKGROUND AND PURPOSE

Hypothermia is effective in improving outcome in experimental models of brain infarction. We studied the feasibility and safety of hypothermia in patients with acute ischemic stroke treated with thrombolysis.

METHODS

An open study design was used. All patients presented with major ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score >15) within 6 hours of onset. After informed consent, patients with a persistent NIHSS score of >8 were treated with hypothermia to 32+/-1 degrees C for 12 to 72 hours depending on vessel patency. All patients were monitored in the neurocritical care unit for complications. A modified Rankin Scale was measured at 90 days and compared with concurrent controls.

RESULTS

Ten patients with a mean age of 71.1+/-14.3 years and an NIHSS score of 19.8+/-3.3 were treated with hypothermia. Nine patients served as concurrent controls. The mean time from symptom onset to thrombolysis was 3.1+/-1.4 hours and from symptom onset to initiation of hypothermia was 6.2+/-1.3 hours. The mean duration of hypothermia was 47.4+/-20.4 hours. Target temperature was achieved in 3.5+/-1.5 hours. Noncritical complications in hypothermia patients included bradycardia (n=5), ventricular ectopy (n=3), hypotension (n=3), melena (n=2), fever after rewarming (n=3), and infections (n=4). Four patients with chronic atrial fibrillation developed rapid ventricular rate, which was noncritical in 2 and critical in 2 patients. Three patients had myocardial infarctions without sequelae. There were 3 deaths in patients undergoing hypothermia. The mean modified Rankin Scale score at 3 months in hypothermia patients was 3.1+/-2.3.

CONCLUSION

Induced hypothermia appears feasible and safe in patients with acute ischemic stroke even after thrombolysis. Refinements of the cooling process, optimal target temperature, duration of therapy, and, most important, clinical efficacy, require further study.

Mechanisms of glucose transport at the blood-brain barrier: an in vitro study

How the brain meets its continuous high metabolic demand in light of varying plasma glucose levels and a functional blood-brain barrier (BBB) is poorly understood. GLUT-1, found in high density at the BBB appears to maintain the continuous shuttling of glucose across the blood-brain barrier irrespective of the plasma concentration. We examined the process of glucose transport across a quasi-physiological in vitro blood-brain barrier model. Radiolabeled tracer permeability studies revealed a concentration ratio of abluminal to luminal glucose in this blood-brain barrier model of approximately 0.85. Under conditions where [glucose](lumen) was higher than [glucose](ablumen), influx of radiolabeled 2-deoxyglucose from lumen to the abluminal compartment was approximately 35% higher than efflux from the abluminal side to the lumen. However, when compartmental [glucose] were maintained equal, a reversal of this trend was seen (approximately 19% higher efflux towards the lumen), favoring establishment of a luminal to abluminal concentration gradient. Immunocytochemical experiments revealed that in addition to segregation of GLUT-1 (luminal>abluminal), the intracellular enzyme hexokinase was also asymmetrically distributed (abluminal>luminal). We conclude that glucose transport at the CNS/blood interface appears to be dependent on and regulated by a serial chain of membrane-bound and intracellular transporters and enzymes.

Expression of endothelial nitric oxide synthase after exposure to perivascular blood

OBJECTIVE

Although nitric oxide (NO) has been implicated in the development of vasospasm after subarachnoid hemorrhage, little is known regarding the time course of NO synthesis in vessel wall after exposure to perivascular blood. This study measures temporal characteristics of changes in vessel wall NO synthesis.

METHODS

Rat femoral arteries exposed to perivascular blood for 3, 5, or 7 days were assayed for the endothelial isoform of NO synthase (eNOS) by Western blot testing. Additionally, rat femoral arteries exposed to perivascular blood for intervals from 3 to 14 days were analyzed by means of immunohistochemistry for eNOS.

RESULTS

Semiquantitative densitometry of femoral artery Western blots demonstrated a biphasic pattern of eNOS expression after exposure to perivascular blood. Compared with control arteries, eNOS expression increased at 3 days (53 +/- 36%), normalized at 5 days (-6 +/- 7%), and decreased by 7 days (-39 +/- 15%). Immunohistochemistry confirmed the changes in expression of immunoreactive eNOS in femoral endothelium during the first week after chronic perivascular blood exposure and apparent reduced eNOS immunostaining, which persisted up to 14 days after application of blood.

CONCLUSION

The expression of endothelial-derived NO in rat femoral artery exposed to perivascular whole blood does not directly correlate with changes in vessel caliber during this interval. The biphasic expression of eNOS observed in these experiments highlights the complexity of processes occurring in the vicinity of the vessel wall during vasospasm and may be related to several mechanisms that modulate vessel tone and response to injury.

Recommendations for the establishment of primary stroke centers. Brain Attack Coalition

OBJECTIVE

To develop recommendations for the establishment and operation of primary stroke centers as an approach to improve the medical care of patients with stroke.

PARTICIPANTS

Members of the Brain Attack Coalition (BAC), a multidisciplinary group of representatives from major professional organizations involved with delivering stroke care. Supplemental input was obtained from other experts involved in acute stroke care.

EVIDENCE

A review of literature published from 1966 to March 2000 was performed using MEDLINE. More than 600 English-language articles that had evidence from randomized clinical trials, meta-analyses, care guidelines, or other appropriate methods supporting specific care recommendations for patients with acute stroke that could be incorporated into a stroke center model were selected.

CONSENSUS PROCESS

Articles were reviewed initially by 1 author (M.J.A.). Members of the BAC reviewed each recommendation in the context of current practice parameters, with special attention to improving the delivery of care to patients with acute stroke, cost-effectiveness, and logistical issues related to the establishment of primary stroke centers. Consensus was reached among all BAC participants before an element was added to the list of recommendations.

CONCLUSIONS

Randomized clinical trials and observational studies suggest that several elements of a stroke center would improve patient care and outcomes. Key elements of primary stroke centers include acute stroke teams, stroke units, written care protocols, and an integrated emergency response system. Important support services include availability and interpretation of computed tomography scans 24 hours everyday and rapid laboratory testing. Administrative support, strong leadership, and continuing education are also important elements for stroke centers. Adoption of these recommendations may increase the use of appropriate diagnostic and therapeutic modalities and reduce peristroke complications. The establishment of primary stroke centers has the potential to improve the care of patients with stroke. JAMA. 2000.

Prospective randomized studies for carotid endarterectomy

The clinical trial has become the standard method used to evaluate surgical procedures. Regarding carotid endarterectomy, clinical trials have reformed the indications for surgery as a means of decreasing the risk of stroke. The methodology and results from significant trials for the symptomatic and asymptomatic patient with carotid stenosis are described. Critical evaluation of these trials is necessary for the discerning surgeon to form a rational approach to clinical practice in carotid disease.

Inhibition of rat smooth muscle proliferation by radiation after arterial injury: temporal characteristics in vivo and in vitro

Although several studies have suggested that inhibition of arterial narrowing by radiation after angioplasty is dependent on both time and dose, little is known regarding the temporal aspects of this effect and the mechanisms by which radiation affects the response of smooth muscle cells to injury. To determine the time course of inhibition of intimal hyperplasia by radiation, 135 rats were given single-fraction external gamma irradiation (1-10 Gy) to one carotid artery at intervals from 5 days before to 5 days after bilateral carotid artery balloon catheter injury, and intimal cross-sectional area was determined from histological sections at 20 days after injury. There was a prominent time- and dose-dependent inhibition of intimal hyperplasia by radiation when it was administered before or after balloon injury, with the greatest effect noted within 24 h before or after injury. To investigate the effect of radiation on smooth muscle cell growth (by cell counting) and proliferation, cell cycle kinetics (by BrdU incorporation), and cell killing (by clonogenic assay), smooth muscle cell cultures derived from rat aortic explants were seeded in equine plasma to induce quiescence, and radiation (2.5-10 Gy) was administered at various intervals before or after synchronous growth stimulation by 10% whole blood serum. A similar time and dose dependence was noted in growth kinetics, BrdU incorporation and cell killing for smooth muscle cells irradiated in vitro; in each case, the effect was most prominent for radiation administered in temporal proximity to stimulation with whole blood serum. By Western blot analysis, cultured smooth muscle cells showed a rapid time-dependent increase in Cdkn1a (formerly known as p21) protein expression, followed by a delayed increase in Tp53 (formerly known as p53) expression after irradiation. Activation of intracellular caspases, manifest by proteolytic poly(ADP-ribose) polymerase (PARP) cleavage, was not detected in smooth muscle cell cultures after irradiation. These observations suggest that radiation limits intimal hyperplasia in vivo by a transient, reversible process. Although apparent cytotoxic injury occurs in vitro, apoptosis of smooth muscle cells is not apparent. Both inhibition of proliferation of smooth muscle cells and cell cycle delay may contribute to inhibition of intimal hyperplasia in vivo by radiation.

Effects of radiation on cerebral vasculature: a review

Radiation therapy plays a critical role in the treatment of central nervous system neoplasms and cerebral arteriovenous malformations. The deleterious effects of radiation on cerebral arteries may be the primary limitation to these treatment methods, as radiation may cause a variety of cerebrovascular injuries and hemodynamic changes. Radiation-induced changes in the cerebral arterial wall are determined by a number of cellular processes in endothelium and smooth muscle cells that modulate differences in radiosensitivity and phenotypic expression. The histopathological findings in arterial radiation injury include vessel wall thickening, thrombosis, luminal occlusion, and occasional telangiectases. Mechanisms for radiation injury to blood vessels include phenotypic changes in normal vessel wall cells (especially endothelium) manifested by the expression or suppression of specific gene and protein products that affect cell cycle progression or cellular proliferation or demise via cytotoxic injury or apoptosis. This review describes the molecular and cellular events involved in the systemic and cerebral vascular response to radiation and the potential means by which these responses may be influenced to augment the therapeutic effects of radiation while minimizing the untoward consequences.

Complex right hemisphere developmental venous anomaly associated with multiple facial hemangiomas. Case report

Complex developmental venous anomalies (DVAs) represent variations of normal cerebral venous drainage and consist of dilation of the superficial and/or deep venous system. These rare anomalies can occur unilaterally or bilaterally, supratentorially or infratentorially, focally or they can affect the entire hemisphere. Some DVAs are associated with cervicofacial venous malformations or facial lymphatic malformations. Anomalies of this type are generally clinically silent, and cerebral dysfunction is usually absent. Symptoms, when they occur, are most commonly headache or mild seizure disorders. The angiographic findings are striking, with well-formed but enlarged transcerebral medullary and deep and/or superficial cortical veins. Opacification of these venous structures occurs within the same time frame as a normal angiographic venous phase. The authors report the case of a 33-year-old man in whom a large inoperable arteriovenous malformation had been previously diagnosed and who presented with seizures. Repeated magnetic resonance imaging and angiography demonstrated abnormally dilated transcerebral, superficial, and deep venous structures involving the entire right hemisphere with no identifiable nidus. Additionally, multiple bilateral benign facial hemangiomas were present in this patient. It is important to recognize this rare venous appearance as a developmental variant and not mistake it for an arteriovenous malformation or a partially thrombosed vein of Galen malformation. Because these venous anomalies are extreme variants of the normal venous system, hemorrhage rarely, if ever, occurs and the patient can be reassured that no interventional or surgical therapy is necessary or warranted.

Analysis of outcome in carotid endarterectomy trials

The trials for carotid endarterectomy have had a major impact on the practice of medicine. Beyond demonstrating the efficacy of this procedure for stroke prevention in certain patient cohorts, these studies have set a standard for the evaluation of surgical procedures by carefully planned, scientifically rigorous, prospective randomized controlled trials. In addition, data from these trials have been used to develop clinical guidelines (2, 12, 24), determine reimbursement policies, and establish criteria for perioperative morbidity. Concordance of methodology (especially primary outcome measures) among the various trials has enabled important valid comparisons between different patient cohorts. The benefit provided by carotid endarterectomy in most trials was so profound that the relative imprecision of stroke-related outcome measures did not significantly affect the findings. New outcome measures for stroke that evolved during these studies are being applied to ongoing trials for a variety of stroke therapies.

Destructive tophaceous calcium hydroxyapatite tumor of the infratemporal fossa. Case report and review of the literature

Tophaceous pseudogout is one of the rarest forms of crystal deposition disease, typically presenting as a destructive and invasive mass involving the temporomandibular joint or the infratemporal fossa region in the absence of any other articular manifestations. Previous cases have been assumed to be caused by calcium pyrophosphate dihydrate (CPPD) crystal deposition, based on finding weakly birefringent crystals in the involved tissues. The authors present the unique case of a 65-year-old woman with a destructive and invasive facial mass extending to the middle cranial fossa with microscopic and clinical features consistent with tophaceous pseudogout. High-resolution x-ray crystallographic powder diffraction and Fourier transformed infrared spectroscopy subsequently revealed that the crystals were composed of calcium hydroxyapatite without CPPD. The patient was later found to have primary hyperparathyroidism and mild hypercalcemia. This case demonstrates that tissue deposits of calcium hydroxyapatite can cause a destructive and invasive mass containing weakly birefringent crystals and raises the question of whether previous cases attributed to tophaceous pseudogout resulting from CPPD actually were composed of birefringent calcium hydroxyapatite.

Traumatic leptomeningeal cyst in an adult: a case report and review of the literature

BACKGROUND

Traumatic leptomeningeal cyst as a complication of skull fractures was initially thought to occur primarily in the pediatric population. The occurrence of a traumatic leptomeningeal cyst in the adult population is rare.

CASE DESCRIPTION

A lump in the right parietal region of this 53-year-old man prompted a computed tomography (CT) scan. The patient denied any symptoms and was in good health. Examination confirmed a firm, nontender, nonpulsatile mass in the right parietal region of the skull. The CT scan demonstrated a 4 x 3 cm area of irregular bone destruction involving both the inner and outer table of the skull. At operation a distinctly raised paper-thin outer table was noted, and underneath was a soft, tan-colored mass, which measured approximately 2 x 2 cm and was connected to the underlying brain through a 1 cm dural defect. The extradural portion of the mass was amputated, the dura repaired with a pericranium patch, the skull defect was repaired with a split thickness bone graft, and the final pathology was congruent with gliotic brain.

CONCLUSION

Although rare, this case demonstrates a traumatic leptomeningeal cyst in an adult.

Cerebral vasospasm

Established vasospasm is refractory to vasodilators, although certain agents (nimodipine or papavarine) may reverse early vasospasm when administered in high local concentrations. Calcium channel antagonists do not affect the incidence of arteriographic vasospasm and probably improve outcome by other mechanisms. Mechanical dilatation of cerebral arteries in chronic vasospasm (angioplasty) produces a long-lasting increase in arterial caliber. Prolonged exposure of cerebral arteries to perivascular blood (probably OxyHb) is necessary for the development of vasospasm. Experimental data have implicated lipid peroxidation or inflammatory responses in the pathogenesis of vasospasm. OxyHb is the most likely pathogenic agent for vasospasm, although the specific mechanism is uncertain. OxyHb causes vasoconstriction by agonist-mediated SMC contraction and catalyzes the formation of reactive oxygen species with subsequent lipid peroxidation. Morphologic changes in SMC have been consistently observed in human and experimental vasospasm. Chronic exposure to perivascular blood produces reduced vessel wall compliance and insensitivity to vasoconstrictors and vasodilators. Although endothelial damage after SAH is sufficient to stimulate only minimal SMC proliferation, the physiologic response of injured endothelium may be manifested by increased ET-1 secretion, augmented platelet adherence, and increased permeability.

Balloon angioplasty for the treatment of vasospasm: results of first 50 cases

OBJECTIVE

To report the results of the first 50 consecutive patients with vasospasm secondary to subarachnoid hemorrhage treated with balloon angioplasty after failure of medical management.

METHODS

Retrospective uncontrolled study of 50 consecutive patients treated with balloon angioplasty between February 1988 and July 1992. Forty-six had objective clinical deterioration despite maximal medical therapy, whereas four were treated on the basis of rapidly accelerating transcranial Doppler velocities and decreased regional blood perfusion detected by technetium-99m-exametazime brain single photon emission computed tomography. All patients had evidence of marked vasospasm demonstrated by angiography. Thirty-two (64%) and 46 (92%) patients underwent angioplasty within 12 and 18 hours, respectively.

RESULTS

Of the patients with clinical evidence of vasospasm-induced ischemia, 28 (61%) showed sustained neurological improvement within 72 hours of angioplasty. Three (6%) patients deteriorated within 72 hours after angioplasty, with two (4%) patients dying immediately after angioplasty as a result of vessel rupture and the other patient's Glasgow Coma Scale score decreasing by 2. Two additional patients in poor condition with Hunt and Hess Grade V at the time of angioplasty subsequently died during hospitalization. Two other patients died as a result of unclipped aneurysms that subsequently bled 4 and 12 days after angioplasty, respectively. The improvement demonstrated clinically, angiographically, and by transcranial Doppler after angioplasty was sustained, with only one patient requiring subsequent angioplasty of a previously dilated segment (total, 170 vessel segments dilated). Two patients developed vasospasm in previously undilated segments.

CONCLUSION

Timely balloon angioplasty can reverse delayed ischemic deficit caused by vasospasm in patients for whom medical therapy has failed.

Comparison of balloon angioplasty and papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT

The purpose of this study was to test the hypothesis that balloon angioplasty is superior to papaverine infusion for the treatment of proximal anterior circulation arterial vasospasm following subarachnoid hemorrhage (SAH). Between 1989 and 1995, 125 vasospastic distal internal carotid artery or proximal middle cerebral artery vessel segments were treated in 52 patients.

METHODS

Blood flow velocities of the involved vessels were assessed by using transcranial Doppler (TCD) monitoring in relation to the day of treatment with balloon angioplasty or papaverine infusion. Balloon angioplasty and papaverine infusion cohorts were compared based on mean pre- and posttreatment velocity at 24 and 48 hours using the one-tailed, paired-samples t-test. Balloon angioplasty alone was performed in 101 vessel segments (81%) in 39 patients (75%), whereas papaverine infusion alone was used in 24 vessel segments (19%) in 13 patients (25%). Although repeated treatment after balloon angioplasty was needed in only one vessel segment, repeated treatment following papaverine infusion was required in 10 vessel segments (42%) in six patients because of recurrent vasospasm (p < 0.001). Seven vessel segments (29%) with recurrent spasm following papaverine infusion were treated with balloon angioplasty. Although vessel segments treated with papaverine demonstrated a 20% mean decrease in blood flow velocity (p < 0.009) on posttreatment Day 1, velocities were not significantly lower than pretreatment levels by posttreatment Day 2 (p = 0.133). Balloon angioplasty resulted in a 45% mean decrease in velocity to a normal level following treatment (p < 0.001), a decrease that was sustained.

CONCLUSIONS

Balloon angioplasty is superior to papaverine infusion for the permanent treatment of proximal anterior circulation vasospasm following aneurysmal SAH.

Progressive aneurysmal degeneration of cortical venous drainage of dural arteriovenous malformations: case report

OBJECTIVE AND IMPORTANCE

The development of a venous aneurysm associated with dural arteriovenous malformations rarely has been documented in the literature.

CLINICAL PRESENTATION

A 64-year-old man with known dural arteriovenous malformations developed a venous aneurysms, as shown on sequential angiograms obtained during 2 years.

INTERVENTION

The dural arteriovenous malformations were treated with neuroendovascular embolization and then surgical excision.

CONCLUSION

The clinical presentation, diagnosis, and treatment of this unusual case are presented.

The potential role of external beam radiation in preventing restenosis after coronary angioplasty

The potential role of radiation in the prevention of coronary artery restenosis after angioplasty has generated much recent interest. Animal research and pilot clinical efforts have focused primarily on intraluminal methods of radiation delivery. This article reviews the experience to date with external beam radiation in restenosis prevention and suggests issues that should be considered from the standpoint of both external beam and intravascular radiotherapy. External beam radiation can certainly play an effective role in clinical studies of coronary artery restenosis, and a multicenter randomized trial of external beam radiation after coronary angioplasty has been initiated.

Reduction of intracellular glutathione levels produces sustained arterial narrowing

OBJECTIVE

Although lipid peroxidation and alterations in endogenous antioxidants have been hypothesized to contribute to cerebral vasospasm after subarachnoid hemorrhage, there has been no direct evidence demonstrating the relationship between oxidative stress and delayed arterial narrowing. To elaborate the role of the endogenous intracellular antioxidant and electron exchanger glutathione (GSH) in cerebral vasospasm, rat femoral arteries were treated with perivascular application of I-buthionine-(SR)-sulfoximine (BSO), which inhibits the synthesis of GSH.

METHODS

To determine the dose-response relationship, BSO at doses of 10 to 100 mg/ml, in platelet-rich plasma, was applied for 7 days to rat femoral arteries in vivo. Vessels were then perfusion-fixed for morphometric analysis of luminal cross-sectional area. To determine the time course of arterial narrowing, BSO (75 mg/ml) was applied to femoral arteries for 1, 3, 7, or 21 days before histological analysis, as described above. With rats treated with 50 to 100 mg/ml BSO, exogenous GSH (100 mg/kg) was administered, by intraperitoneal injection, daily for 7 days. To demonstrate the mechanism of BSO effects in smooth muscle cells (SMCs), cultured rat aortic SMCs were treated with 1 mmol/l BSO for 24 hours and assayed for intracellular levels of GSH and two products of lipid peroxidation, malondialdehyde and 4-hydroxyalkenal.

RESULTS

Compared with control arteries treated with platelet-rich plasma alone, perivascularly administered BSO applied for periods of 1 to 21 days produced sustained and reversible narrowing of rat femoral arteries with a time course, severity, and histological appearance analogous to those observed after perivascular application of whole blood. BSO-induced arterial narrowing was dose-dependent, with 60% reductions in the luminal cross-sectional area being noted at 75 and 100 mg/ml (P < 0.005). Systemic administration of exogenous GSH slightly inhibited the effect of BSO on arterial narrowing, although the inhibition was not statistically significant. Cultured rat aortic SMCs exposed to BSO for 24 hours showed a 70% decrease in intracellular GSH levels (P = 0.03); levels of two products of lipid peroxidation, malondialdehyde and 4-hydroxyalkenal, were increased by 25% (P = 0.24) and 38% (P = 0.09), respectively.

CONCLUSION

These data support the hypothesis that diminished intracellular levels of GSH may produce delayed chronic arterial narrowing after subarachnoid hemorrhage. The specific mechanism by which GSH levels modulate vasoconstriction remains uncertain but may involve endogenous antioxidant capacity in SMCs.

Gamma radiation effect on vascular smooth muscle cells in culture

PURPOSE

Prior work in our laboratory demonstrated that external gamma irradiation administered within 48 h following balloon catheter carotid artery injury in rats produced a marked inhibition of intimal hyperplasia and restenosis. The current study used smooth muscle cells (SMC) in vitro to examine the radiation dose response and to investigate the cellular mechanism by which radiation inhibits SMC proliferation.

METHODS AND MATERIALS

Quiescent rat aortic SMC in plasma were refed with whole blood serum to stimulate synchronous proliferation and immediately irradiated with single fraction doses of 1.25-20 Gy.

RESULTS

Comparison between a micronucleus assay and a clonogenic assay indicated a dose-dependent inhibition of SMC growth, with an ED50 at 2-3 Gy. The micronucleus assay also demonstrated a dose-dependent increase in apparent chromosomal damage at 72 h after irradiation. Inhibition of SMC growth by radiation did not correlate with changes in intracellular or released mitogenic activity. Furthermore, there was no evidence of apoptosis in irradiated SMC up to 96 h after treatment.

CONCLUSION

Radiation likely inhibits SMC proliferation after arterial injury by a dose-dependent mechanism of lethal and/or sublethal cellular injury leading to clonogenic cell death.

Effects of irradiation geometry on treatment plan optimization with linac-based radiosurgery

A comparison was made of different treatment plans to determine the effect on the three-dimensional dose distributions of varying the allowed parameters in linac-based stereotactic radiosurgery with circular collimators; these parameters are arc position, length, and weighting, and collimator diameter. For the class of eccentrically shaped target volumes that are not so irregular as to require several separate isocenters, it was found that superior dose distributions could be achieved by varying arc length, arc position, arc weighting, and collimator diameter. An analysis of the results achieved with an automated planning program indicates that, in general, the variables of arc position and arc length are of greater importance than collimator size or beam weighting. However, there are cases where varying these latter two parameters does result in markedly better dose distributions. A deeper investigation into the effects of multiple collimators on the dose distribution in the area of steepest gradient demonstrated that multiple collimator sizes do not significantly degrade the dose falloff, which is in fact mostly determined by the effects of intersecting arcs.

Transcranial Doppler in the evaluation of internal carotid artery dissection

BACKGROUND AND PURPOSE

A subject with dissection of the internal carotid artery (ICA) may present with a variety of symptoms, from headache to stroke. Thus far, it has not been possible to identify the subset of patients at risk for cerebral ischemia. Because the majority of these ischemic events are secondary to embolic phenomena, we used transcranial Doppler (TCD) evaluation with emboli monitoring to study 17 consecutive patients with ICA dissection treated at Harborview Medical Center, Seattle, Wash, during a 2-year period from 1992 until 1994.

METHODS

Ten patients with ICA dissection secondary to trauma and seven with spontaneous ICA dissection were diagnosed by carotid angiography and studied by TCD from the time of diagnosis through initiation of therapy. Emboli monitoring was performed in the middle cerebral artery (MCA) ipsilateral to the dissection at the initial evaluation and intermittently thereafter to ensure that the emboli stopped with treatment.

RESULTS

Emboli were detected in the MCA distal to the dissection in 10 of 17 patients (59%). Patients with microemboli detected by TCD presented with a stroke (70%) much more frequently than those without emboli (14%) (P=.0498). The presence of a pseudoaneurysm did not increase the risk of either microemboli or stroke.

CONCLUSIONS

We have demonstrated a high incidence of intracranial microemboli in the MCA distal to carotid dissections and a significant correlation between the presence of emboli and stroke. TCD can therefore be used as an adjunctive tool to manage patients with suspected carotid dissection and may prove useful in evaluating the efficacy of treatment in reducing microemboli and subsequent stroke.

A technique for interactive image-guided neurosurgical intervention in primary brain tumors

Interactive image-guided neurosurgical techniques allow safer and more complete cytoreduction of gliomas. This is most significant for low-grade tumors, whose configurations and margins are perhaps better appreciated by reference to registered MR images rather than by reliance on direct visualization using microscopic illumination. Spatially registered electro-physiologic recordings of intraoperative cortical stimulation to map language and motor function can increase the margin of safety for performing radical resections. By individualizing approaches and optimizing results, these technologies promise a new degree of standardization of outcome after resective surgery for all glial tumors.

Antioxidant and iron-chelating agents in cerebral vasospasm

Prior work in our laboratory showed that the perivascular application of deferoxamine (an antioxidant and iron-chelating agent) inhibited delayed arterial narrowing after chronic blood exposure in a rat femoral artery model of vasospasm. To determine which of these mechanisms was operant in vasospasm, we compared deferoxamine with two agents (ascorbic acid and U74389F) that have antioxidant but not iron-chelating capacity. For the systemic application of drugs in 23 rats, whole blood encased in a silastic cuff was applied to the right femoral artery of each rat; whole-blood serum (lacking erythrocytes) was similarly applied to the left femoral artery. Deferoxamine (30 mg/kg/d), ascorbic acid (1000 mg/kg/d), U74389F (30 mg/kg/d), or pH-matched control vehicle was administered three times daily by intraperitoneal injection for 7 days. After exposure to whole blood, arteries treated with intraperitoneal vehicle showed an 85% reduction in the lumen, compared with vessels exposed to erythrocyte-free serum (P < 0.001). Intraperitoneal ascorbic acid and U74389F produced moderate amelioration in arterial narrowing (53 and 61% decrease, respectively, in the lumen versus controls; P < 0.05 versus vehicle); deferoxamine had no significant effect when administered intraperitoneally. To test the efficacy of these agents by the perivascular application of drugs, whole blood was applied to both femoral arteries in each of 25 rats. Solutions of deferoxamine (10 mg/ml), ascorbic acid (50 or 100 mg/ml), or U74389F (15 or 30 mg/ml) were directly applied to the perivascular thrombus surrounding the femoral arteries, compared with vehicle applied to contralateral vessels. The perivascular application of 50 mg of ascorbic acid (36% reduction, P < 0.05), 100 mg of ascorbic acid (31% reduction, P < 0.01), or 10 mg of deferoxamine (41% reduction, P < 0.05) significantly inhibited arterial narrowing, compared with vehicle. The application of U74389F at a dose of 15 or 30 mg directly into the perivascular thrombus produced nonsignificant reduction in arterial narrowing. These data suggest that mechanisms other than direct iron toxicity, such as generation of cytotoxic free radicals, may play an important role in cerebral vasospasm. In addition, the route of administration and concentration of drugs in the perivascular region adjacent to the thrombus may be critical to their efficacy.

Persistent feeding arteries to angiographically completely embolized arteriovenous malformation demonstrated by intraoperative color-flow Doppler testing: report of two cases

Two cases of arteriovenous malformation (AVM) treated preoperatively by endovascular embolization that appeared to be completely occluded after embolization are presented. Seven and 12 days later, respectively, these patients underwent resection of their AVM. At the time of surgery, intraoperative color-flow Doppler studies revealed persistent feeding arteries to an active residual nidus of the AVM. The significance of this finding is presented in light of previous published literature.

Improved outcome after rupture of anterior circulation aneurysms: a retrospective 10-year review of 224 good-grade patients

Several significant diagnostic and therapeutic advances in the management of subarachnoid hemorrhage have emerged during the last 10 years. The present study was undertaken to determine whether these advances have improved overall outcome in patients of low surgical risk and what factors predict outcome. The authors retrospectively reviewed the management of good-grade patients seen at the Harborview Medical Center at the University of Washington, who suffered ruptured anterior circulation aneurysms between 1983 and 1993. The results in this series demonstrate that favorable outcomes occurred in 96.8% of patients designated Hunt and Hess Grade I, 88.3% of those assigned Grade II, and 81.3% of those deemed Grade III after rupture of anterior circulation aneurysms. On the basis of clinical and radiographic factors present at admission, correct prediction can be made about all favorable, but only 17% of unfavorable outcomes. During the decade under investigation, the authors observed a significant (p = 0.002) increase in the number of favorable outcomes: 74.5% of patients treated during the first management period (1983-1987); 87% of patients treated during the second period (1987-1990); and 93.5% of patients treated during the third management period (1990-1993) experienced favorable outcomes. Improvements in critical-care techniques and the management of vasospasm may be associated with the improved outcome observed during this series.

Radiation inhibition of intimal hyperplasia after arterial injury

To demonstrate the effect of gamma radiation on proliferating smooth muscle cells in vivo, a standardized bilateral carotid balloon catheter arterial injury was produced in 45 rats and doses from 0-20 Gy were delivered to the right carotid artery at 24 h after injury. At 20 days after injury, cross-sectional area of intima was determined from axial histological sections. Compared to contralateral, nonirradiated balloon-injured arteries, radiation produced a significant dose-dependent reduction in intimal cross-sectional area, with a 50% decrease at 5-7.5 Gy. To determine the effect of timing of irradiation on intimal hyperplasia, 30 rats with bilateral carotid injury received unilateral cervical irradiation at doses of 1, 5 or 10 Gy administered at either 1, 3 or 5 days after injury. The radiation dose (P = 0.0002), timing of irradiation (P = 0.003) and an interaction between timing and dose (P = 0.0278) were significantly associated with reduction in neointimal cross-sectional area. To determine the effects of radiation on intimal hyperplasia at later intervals, rats irradiated with 15 (n = 5) or 20 Gy (n = 5) were euthanized at 3 months after injury. A significant persistent reduction in intimal cross-sectional area for irradiated arteries at 3 months was associated with minimal apparent radiation effects upon adjacent tissue. These data suggest that external gamma irradiation at the single doses used effectively inhibits smooth muscle proliferation and intimal hyperplasia in the rat balloon catheter injury model in a time- and dose-dependent manner.

Duplex accuracy compared with angiography in the Veterans Affairs Cooperative Studies Trial for Symptomatic Carotid Stenosis

Duplex ultrasonography is frequently used for noninvasive screening for extracranial occlusive disease. In a multicenter, prospective, randomized trial for carotid endarterectomy in symptomatic patients, the duplex ultrasound examination was compared with conventional angiographic findings for internal carotid artery (ICA) stenosis in 178 patients. Angiograms were interpreted by radiologists both at local medical centers and at a central site; the angiographic determination of ICA stenosis was calculated as percent diameter at the point of maximal narrowing compared with the normal distal ICA. Comparisons were made for 328 arteries, including both the symptomatic (> 50% stenosis determined by angiography) and the asymptomatic (variable degrees of stenosis) sides. Duplex ultrasonography sensitivity varied from 0.24 for 30 to 49% stenosis to 0.71 for 50 to 79% stenosis and 0.91 for ICA occlusion. Using a 50% stenosis cutpoint, duplex ultrasonography sensitivity was 0.90 with a specificity of 0.76. Duplex scan readings underestimated the degree of stenosis in the 30 to 49% stenosis group in 48% of the cases. There was no apparent relationship between the accuracy of stenosis determinations and that of external carotid artery stenosis, carotid plaque morphology, or ulceration determinations by ultrasound. On the basis of the benefit provided by carotid endarterectomy in symptomatic patients with high-grade lesions, duplex ultrasound accuracy is essential if noninvasive testing is used to make clinical decisions. In situations in which duplex findings may not be reliable, such as in the mild-to-moderate stenosis and occlusion categories, carotid angiography may be indicated.

Kinetics of bromodeoxyuridine uptake by smooth muscle cells after arterial injury

The time course of 5-bromo-2'-deoxyuridine (BrdU) uptake by medial and neointimal smooth muscle cells was examined in rat carotid arteries at periods of 1-20 days after balloon catheter injury. DNA-incorporated BrdU was determined by the indirect immunoperoxidase technique in both plastic- and paraffin-embedded specimens. The BrdU labeling index (LI) peaked at 48 h in the media (19.9% paraffin, 9.4% plastic) and at 5 days in the neointima (55.4% paraffin, 60.2% plastic). Immunohistochemistry for the endogenous marker proliferating cell nuclear antigen was variable and generally less reliable than BrdU. Using total viable medial smooth muscle cell number as an index of medial injury, the LI for BrdU was directly proportional to the extent of injury at 48 h, and correlated with loss of actin immunoreactivity. BrdU immunohistochemistry is a reliable alternative to [3H]-thymidine autoradiography for short-term labeling in this model. Proliferation of smooth muscle cells in this model is likely related to the degree of injury to the media.

Unilateral vestibular schwannoma in a child with prior orbital rhabdomyosarcoma

In the absence of neurofibromatosis, vestibular schwannomas (acoustic neuromas) are rarely found in children. We report a case of a 13-year-old boy who presented with unilateral vestibular schwannoma 11 years after resection of an orbital rhabdomyosarcoma. The coincidence of these tumors has not been previously reported.

Stereotactic radiosurgery: a review and comparison of methods

PURPOSE

Stereotactic radiosurgery (SRS) is an evolving modality for treating well-circumscribed intracranial lesions. Different physical methods have been developed to deliver highly localized dose distributions accurately. We review the different methods and the documented clinical results to present a coherent view of radiosurgery, and to aid physicians and physicists in the appropriate use of this modality.

DESIGN

A review of the medical physics and clinical literature was conducted. The physical aspects of the different methods and their impact on treatment were summarized. Results were compiled from those individual clinical series with adequate follow-up data to compare the various modalities with respect to treatment outcome for benign tumors, metastases, and vascular malformations.

RESULTS

The physical accuracy was comparable between radiosurgical methods. Differences between gamma radiation and linear accelerator methods had little effect on the dose distribution for single isocenter treatments. Charged particle methods could produce better dose localization for large lesions (> 25 cm3) than was possible with photon methods. Clinical results indicate similar lesion control rates between all radiosurgical methods. There was a progressive increase in the median size of treated lesions for gamma radiation, linear accelerator, and charged particle methods.

CONCLUSION

For small lesions (< 5 cm3), physical dose distributions are similar for the photon methods, but linear accelerator methods offer more flexibility for the treatment of intermediate-sized (5 to 25 cm3) lesions in applying future technical developments. More clinical results are needed before firm conclusions can be drawn on the type of lesions to be treated, and the dose-volume parameters to be used.

Gamma irradiation inhibits neointimal hyperplasia in rats after arterial injury

BACKGROUND AND PURPOSE

Restenosis complicates a significant proportion of endovascular and open vascular procedures such as carotid endarterectomy. In contrast to the primary atheroma, restenosis is characterized by intimal hyperplasia of vascular smooth muscle cells. We hypothesized that gamma radiation would reduce restenosis by limiting intimal hyperplasia after arterial injury.

METHODS

To demonstrate the effect of gamma radiation on smooth muscle hyperplasia in vivo, a standardized bilateral carotid balloon catheter arterial injury was produced in 37 rats. A single dose of 750, 1500, or 2250 cGy (1cGy = 1 rad) gamma radiation was delivered to the right carotid artery at either 1 or 2 days after injury; the shielded contralateral carotid artery served as matched control. At 21 days after injury, vessels were perfusion-fixed in situ, and cross-sectional area of neointima was determined from axial sections using image analysis.

RESULTS

Marked reductions in neointimal cross-sectional area were demonstrated in vessels subjected to 1500- and 2250-cGy radiation at both 1 and 2 days after injury. A less prominent effect was noted for 750 cGy, reaching statistical significance only at 2 days after injury. By two-way ANOVA, radiation dose (P = .0002), timing of radiation delivery (P = .003), and an interaction between timing and dose (P = .0278) were significantly associated with reduction in neointimal cross-sectional area. At 1500 cGy, delivery of radiation 1 day after injury inhibited neointimal hyperplasia more prominently than the same dose 2 days after injury; a dose-response relation was evident at 1 day.

CONCLUSIONS

Radiation may be an important adjunctive therapy for reducing the incidence of restenosis after angioplasty or endarterectomy.

Severe symptomatic vasospasm: the role of immediate postoperative angioplasty

The clinical success of angioplasty for symptomatic vasospasm following subarachnoid hemorrhage (SAH) depends on early intervention and can best be achieved after the aneurysm is occluded. However, patients presenting with unsecured ruptured aneurysms and established clinical vasospasm offer a dilemma for the surgeon. The authors describe the cases of five such patients who underwent acute clipping of aneurysms followed by immediate postoperative angioplasty between 1988 and 1992. All were referred at least 5 days after SAH. Severe vasospasm compatible with the clinical presentation was confirmed by angiography. The patients met the department's criteria for angioplasty but, because of unclipped aneurysms, were first taken patients met the department's criteria for angioplasty but, because of unclipped aneurysms, were first taken to the operating room for a craniotomy and aneurysm obliteration. Angiography was repeated immediately after surgery. Arterial narrowing had progressed during surgery in two patients. In all patients, postoperative mechanical dilatation was achieved with the use of a silicone microballoon. Following angioplasty, transcranial Doppler ultrasound flow velocities and single-photon emission computerized tomography evaluation indicated improved cerebral perfusion compared to preoperative determinations. Four patients improved clinically and made a good recovery. In this subgroup of patients presenting with proven symptomatic vasospasm and an unclipped but ruptured aneurysm, urgent surgical obliteration of the aneurysm followed by immediate postoperative angioplasty may be a safe and reasonable means to improve outcome.

Local application of calcium antagonists inhibits intimal hyperplasia after arterial injury

The local effect of the calcium channel antagonist diltiazem and the protein kinase inhibitor 1-5-(isoquinoline sulfonyl)-5-homopiperazine HCL (HA1077) on neointimal formation after arterial injury were investigated by the use of a perivascular drug-delivery system. Bilateral carotid artery balloon injury was produced in 130 rats. In six groups of 10 rats each, diltiazem or HA1077 at three doses (low, 0.2 mg; medium, 1 mg; high, 5 mg) was mixed with the drug-delivery polymer poly(vinyl) alcohol and applied to the adventitial surface of the injured right carotid artery enclosed by a Silastic cuff; 10 control animals received polyvinyl alcohol only in the silastic cuff. In all animals, the contralateral injured artery without the cuff served as a control. At 10 and 20 days after the injury, the intimal cross-sectional area was determined from light microscopic sections for the injured segment of both carotid arteries. In six additional groups of 10 rats each, treated as above, levels of diltiazem and HA1077 in plasma were measured at periods from 1 hour to 5 days after perivascular application. At 10 days after endothelial injury, animals receiving high-dose diltiazem or HA 1077 (5 mg) demonstrated significant reductions in neointimal area compared with polyvinyl alcohol controls for both treated and contralateral untreated vessels. At 20 days after injury, neointimal hyperplasia was inhibited only on the treated side in both high-dose groups. Perivascular diltiazem and HA1077 at lower doses (1 or 0.2 mg) did not affect neointimal area at 10 or 20 days in either treated or untreated arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Basic fibroblast growth factor and transforming growth factor beta-1: synergistic mediators of angiogenesis in vitro

We investigated the relative roles of basic fibroblast growth factor (bFGF) and transforming growth factor beta-1 (TGF-b) on bovine aortic endothelial cell mitogenesis and morphogenesis using two-dimensional Petri dish cultures and a three-dimensional hydrated collagen gel. bFGF alone stimulated endothelial cell proliferation with an EC50 of 0.5 ng/ml. At bFGF levels greater than 2.5 ng/ml, morphologic alterations in confluent monolayers predominated; cells changed from a cobblestone morphology to an elongated cell pattern and showed enhanced migration into a denuded area of a Petri dish. In the three-dimensional model, exposure of endothelial cell monolayers to high bFGF levels stimulated minor cell migration directly under the monolayer but no invasion into the gel matrix. In combination with bFGF, heparin potentiated morphogenic changes, but not mitogenesis. bFGF modification of the antiproliferative effect of TGF-b in confluent cultures was evidenced by induction of endothelial cell sprouting in response to 0.5 ng/ml TGF-b and 10-20 ng/ml bFGF in two-dimensional cultures. On collagen gels, endothelial cells migrated into the deep layers of the gel in a dose-dependent manner: invasion was maximal at 0.3-0.7 ng/ml TGF-b with decreased invasion at higher concentrations. The optimal collagen concentration that supported cell invasion was 0.075% collagen with the number of invading cells decreasing with increasing collagen gel density. By scanning electron microscopy, invading endothelial cells assumed a fibroblast-like appearance with slender cell extensions. We concluded that bFGF and TGF-b had independent effects on endothelial cell morphology and mitogenesis in culture. In combination at specific doses, these agents stimulated sprouting in the two-dimensional model and cell invasion in a collagen gel model. Morphogenic changes may be the primary event in determining angiogenesis.

Detection of proliferating cell nuclear antigen in gliomas and adjacent resection margins

We describe a technique for estimating the number of proliferating cells in gliomas and adjacent resection cavities after tumor removal. Proliferating cell nuclear antigen (PCNA) is a nuclear protein associated with the cell cycle. Anti-PCNA antibody staining provides a semiquantitative estimate of the number of proliferating cells found in fixed tissue embedded in paraffin. The extent of the staining of tumor cells of glioblastoma multiforme, anaplastic astrocytomas, low-grade gliomas, and other lesions of the brain with anti-PCNA antibody is correlated with the histological diagnosis. In addition, the labeling of the margins after resection of gliomas and other lesions with anti-PCNA antibody is also associated with the histological diagnosis of the lesion. This technique may be useful in estimating the "biological" extent of resection and in predicting the recurrence patterns of gliomas.

Paragangliomas of the sellar region: report of two cases

Two cases of paraganglioma arising from the parasellar region are presented. Both occurred in middle-aged women who sought treatment of headaches but who had no endocrinological dysfunction; one case was associated with ophthalmoplegia from cavernous sinus involvement. Diagnosis in both cases was confirmed by typical histological appearance and cytochemical demonstration of immunoreactive chromogranin in tumor cells. The pathological features and possible pathogenesis of parasellar paragangliomas are discussed.

Prevention of postoperative intracerebral hemorrhage with topical recombinant factor XIII in the rat

Factor XIII is an endogenous clotting factor that retards thrombus degradation by cross-linking fibrin. To determine the efficacy of Factor XIII as a topical clot-stabilizing agent in preventing postoperative hemorrhage associated with coagulopathy, a rat model of experimental craniotomy and standardized bilateral frontal corticectomy was developed. In 25 rats (50 lesions), recombinant human Factor XIII or placebo solution was topically applied to corticectomy cavities after hemostasis was achieved; each animal served as its own control. In 20 rats, heparin sulfate (100 U/kg.h) was initiated intraperitoneally 3 days after surgery and was continually administered by an Alzet pump for 7 days, compared with a control group of 5 rats receiving saline intraperitoneally. The volume of intracranial hemorrhage was quantitatively determined from coronal sections by use of automated image analysis. Large (> 50 mm3) intracerebral hemorrhages were significantly more frequent in placebo (60%)- compared with recombinant Factor XIII (15%)-treated lesions (P < 0.01) in animals receiving heparin. The topical application of clot-stabilizing agents such as Factor XIII may reduce the risk of postoperative intracranial hemorrhage, especially in high-risk patients with coagulopathy.