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The cavernous hemangioma (cavernoma) is increasingly recognized as a vascular malformation of the brain that may present with seizures, hemorrhage, or progressive neurological deficit. Since 1985 we have identified 13 cases of presumed cavernoma of the brain based on the findings on CT, selective angiography, and magnetic resonance (MR) imaging. In each case CT showed a high density lesion that was "occult" or "cryptic" on angiography. However, within all lesions MR revealed a complex internal structure consisting of reticulated patches of high and low intensity signal surrounded by a hypointense rim on T1- and T2-weighted pulse sequences. Of the nine operated cases, five resected specimens were compatible with pure arteriovenous malformations (AVMs), and the other four were mixtures of cavernoma with either AVM or venous angioma. Our experience strongly suggests that the above complex of radiographic findings is not at all specific for the cavernoma. We propose that the major common factor shared by such "cavernomatoid" malformations is low blood flow. We believe low flow lesions follow a relatively benign clinical course, and they readily lend themselves to surgical resection.

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Monitoring evoked potentials from the brain for prolonged periods during neurosurgical procedures ideally requires attached scalp electrodes that may be placed in a sterile field. The limitations of conventional surface and percutaneous electrodes in the operating room environment have led to the development of a disposable curved-needle electrode which is inherently self-retaining. Clinical results have demonstrated the advantages of this new electrode over other electrodes currently used for intraoperative neurophysiological monitoring.

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In vivo O3 exposure followed by in vitro incubation was observed to cause inhibition of mouse RBC deformability. The requirement for in vitro incubation to allow expression of these effects and the potential role for oxidizable membrane components were investigated. Membrane sulfhydryls (SHs) and membrane ATPase are both susceptible to oxidation by O3 and are essential for maintaining RBC membrane deformability. RBC SH levels and ATPase activity were unchanged immediately after exposure of mice to filtered air (controls) or 1 ppm O3. After a subsequent 6-hr in vitro incubation, RBCs from control mice exhibited significant increases in membrane SH and ATPase activity, while SH levels and ATPase activity in RBCs from O3-exposed mice remained unchanged. Although the stimulus for increasing membrane SH and ATPase activity is unclear, these changes appear to be essential to maintaining RBC deformability in vitro and are inhibited by in vivo O3 exposure.

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Two hundred and fifty patients were referred for magnetic resonance imaging (MRI) of the lumbar spine. Computed tomography (CT) and MRI were performed in 50 patients and MRI, CT and myelography in 20 patients. Twenty patients had surgical confirmation of the imaging studies. MRI was best for demonstrating degenerated discs. MRI was better than CT for demonstrating disc bulge without herniation, and MRI was slightly better for herniated disc demonstration than CT. Myelography did not demonstrate degenerated discs.

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Twenty-four members of a family with benign familial chorea underwent testing for evidence of intellectual impairment. Lower verbal intelligence was found in affected individuals compared to unaffected family members, as were deficits in verbal abstract concept formation. These results challenge the notion that benign familial chorea uniformly spares the intellect in all kindreds.

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A simplified technique that uses two radionuclide tracers has been devised to measure local cerebral glucose utilization (ICGU) and local cerebral blood flow (ICBF) in the same rat. The method employs [14C]-2-deoxyglucose and [14C]iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the [14C]iodoantipyrine from the brain sections. The chloroform-extracted autoradiogram yields ICGU, and the difference in tissue carbon-14 concentration between the two autoradiograms permits calculation of ICBF. The double-isotope technique provides values of ICGU and ICBF that are statistically indistinguishable from those derived from conventional single-isotope methods.

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Air embolization of the brain produces cerebral ischemia that can be focal and reversible. The method has previously been hampered by (1) lack of selective arterial injection of the embolus, (2) disruption of local hemodynamic relationships by ligation of major arterial channels, (3) excessive volume of the air embolus, and (4) uncontrolled bubble size. To minimize these factors, a technique was devised in the rat whereby a fine catheter was advanced through a branch of the external carotid artery into the internal carotid artery. Air emboli of 5 microliters were found to arrest blood flow and to attenuate electrical activity in the ipsilateral cerebral hemisphere for seconds to a couple of minutes. The duration of ischemia varied from region to region, and it tended to be prolonged by arterial hypotension. In the nonembolized hemisphere, CBF never declined abruptly (indicating no cross-over of air) although electrical activity was suppressed in two-thirds of the animals.

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Cerebral ischemia was produced in the rat by simultaneous occlusion of the vertebral and carotid arteries according to the method of Pulsinelli and Brierley (Stroke 10: 267, 1979). Local cerebral blood flow (CBF) was determined by polarographic and autoradiographic techniques. Hydrogen-clearance measurements showed that mean CBF fell in four monitored regions of the hemispheres to between 0.11 and 0.18 ml/g/min, being least in deep rostal gray, intermediate in superficial gray, and greatest in deep caudal gray. However, individual animals had local CBF in excess of 0.20 and even 0.30 ml/g/min, and no animal showed zero CBF. When animals were rendered hypotensive (MABP of 50 Torr) during vascular occlusion, mean CBF ranged between 0.03 and 0.10 ml/g/min in the same regional order. With hypotension, total arrest of flow occurred. Autoradiographic data confirmed the above findings and indicated adequate CBF to the lower brainstem. During vascular occlusion, sufficient CBF may be present ot sustain cerebral tissue as in animals with a well developed spinal circulation or an inadvertently patent vertebral artery.

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The short-latency auditory-evoked response was recorded from adult (over 8 wk) and young (16-22 day) mice of the audiogenic seizure-prone DBA/2J (D2) and seizure-resistant C57BL/6J (C6) strains. An auditory complex made up of eleven peaks and troughs was found within the first 20 ms after click stimuli. The latencies of the potentials tended to be shorter in the C6 mice and in the adults of both strains. The ratio of amplitude differences of late to early peaks ('amplitude index') was much larger (P less than 0.01) in D2 mice. The data are consistent with greater neuronal recruitment to acoustic stimuli in the higher-order auditory centers of D2 mice.

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To test the hypothesis that plasma contains native constituents capable of impairing microcirculatory flow in zones of acute ischemic tissue damage, we performed 14C-antipyrine autoradiographic blood flow studies in splenectomized dogs subjected to 35 min of cerebrospinal fluid compression ischemia followed by 30 min of recirculation to the neuraxis. The animals were anticoagulated with heparin and were divided into 4 groups by exposure to various measures before induction of ischemia. Groups 1 and 2 served for comparison with the other groups and underwent, respectively, no glass-wool filtration and glass-wool filtration via an arteriovenous shunt. Post-ischemic brain blood flows in Group 1 were low and focal zones of greatly impaired reperfusion were present. In Group 2, post-ischemic brain blood flows were high and focal perfusion impairment did not occur. Group 3 received homologous purified factor VIII/von Willebrand factor protein (F VIII/vWF) after glass-wool filtration but before induction of ischemia; Group 4 received F VIII/vWF-poor cryoprecipitate at the same time point. The purpose of administering the plasma preparations was to check for the presence of activity that nullified the enhancement of post-ischemic reperfusion expected after exposure to glass-wool. The results indicate that activity deleterious to post-ischemic reperfusion primarily resides in the F VIII/vWF fraction of cryoprecipitate. The F VIII/vWF-poor cryoprecipitate infusate, containing 250 to 800-fold more protein than the F VIII/vWF fraction, produced an intermediate reduction of blood flow.

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