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M Dujovny

Publications and source records attributed to M Dujovny.

At least 55 records · Page 3Linked to original sources
PubMed1997

Microdialysis in the human brain: review of its applications.

The analysis of brain extracellular fluid can provide essential information about both the physiology and the pathology of the human nervous system. The introduction of microdialysis into the clinical sciences has provided a new opportunity to study this environment. Using microdialysis, endogenous substances can be obtained and drugs can be delivered in very close proximity to the receptors and ion channels on neuronal membranes. In this sense, microdialysis can be regarded as a novel technique since it can continuously measure interstitial brain activity in living tissue while causing minimal adverse effects. Although it has been well established as an experimental technique for neurochemistry, the true utility of microdialysis as a clinical tool is still being defined. The potential clinical applications of microdialysis to characterize the human brain extracellular environment in patients with pathologic conditions has grown rapidly. The number of publications in which microdialysis has been performed in clinical studies has been increasing during recent years and this article gives a summary of those reports where microdialysis was applied in the study of human brain disorders.

Brain↗
PubMed1997

Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis.

The syndrome of the trephined has been described in many patients with cranial defects as an indication for cranioplasty. Cerebral blood flow changes, the effect of the atmospheric pressure on the brain, as well as cerebrospinal fluid hydrodynamic changes have been postulated as the possible reasons for this syndrome. Using dynamic phase-contrast magnetic resonance imaging we measured arterial, venous, and cerebrospinal fluid flow into and out of the skull, before and after cranioplasty in one patient whose bone flap was removed because of osteomyelitis. We report significant changes in the oscillatory CSF flow after cranioplasty. A moderate increase in venous outflow as well as a two-fold increase in craniocaudal cerebrospinal fluid systolic flow velocity was measured after the skull closure. The changes in the cerebrospinal fluid oscillatory flow at the level of the craniovertebral junction could reflect changes in the compliance of the craniospinal system produced by closure of the cranial defect.

Adult↗
PubMed1997

Evaluation of cerebral autoregulation following diffuse brain injury in rats.

The normal cerebral circulation has the ability to maintain a stable cerebral blood flow over a wide range of cerebral perfusion pressures and this is known as cerebral autoregulation. This autoregulation may be impaired in the injured brain. Closed head injury was induced in 28 Sprague-Dawley rats weighing 400-450 g. Four groups were studied: control group, head injured rat from meter height using 350 g, 400 g and 450 g respectively. CBF, volume velocity was monitored using laser-Doppler flowmetry together with monitoring of ICP and arterial blood pressure. Correlation to assess the relationship between CBF and CPP was done in each animal every hour. If correlation coefficient was > 0.85 and CPP was within normal range, loss of autoregulation was hypothesized. Chi square test, ANOVA test and unpaired Student's t-test were done and significant level of p < 0.05 was established. Mean CBF in injured rats was significantly lower than controls (p = 0.028) at the fifth hour. CBV was lower in the group of 450 g 1 m impact than in controls at 3 h (p = 0.04). Velocity in the group of all injured rats, was significantly lower than in controls at 3 h (p = 0.032) and at 4 h (p = 0.027). Loss of autoregulation was seen during first four hours after trauma in all groups of rats who sustained injury. Statistical significant difference (p = 0.041) in loss of autoregulation between injured and control animals was seen. No loss of autoregulation was observed in the control group. In conclusion CBF and CPP provide information about loss of autoregulation in diffuse brain injury. Decrease in CBF and increase of ICP is observed as a result of loss of cerebral autoregulation. Knowledge of loss of autoregulation could give important information and help in the management of head injured patients.

Animals↗
PubMed1997

Intraventricular atrial natriuretic peptide for acute intracranial hypertension.

The effect of intraventricular atrial natriuretic peptide (ANP) on elevated intracranial pressure (ICP) was evaluated in a rodent model of global ischemia and reperfusion. ANP administration into the lateral ventricle 30 minutes after reperfusion statistically significantly reduced ICP compared with both vehicle treated animals (p < 0.001) and pretreatment pressures (p < 0.001). The ICP effects of ANP did not coincide with specific changes in regional perfusion parameters measured by laser-Doppler flowmetry. Two different vehicles for ANP were used to verify that the changes in ICP observed were independent of the sodium content administered in the vehicle. Based on the reductions observed in ICP, ANP deserves further evaluation as a treatment modality for the acute elevations in ICP associated with ischemic brain injury.

Acute Disease↗
PubMed1997

Comparative microanatomy of the lateral wall of the 'cavernous sinus' in humans and the olive baboon.

Despite many studies of the 'cavernous sinus' lateral wall, the anatomy of this area remains controversial. We performed a comparative microanatomical and histoarchitectural study in 14 humans and in 10 nonhuman primates (Papio cynocephalus anubis). Venous channels and cranial nerves were embedded in the 'interperiosteodural space'. The dura propria of the lateral wall could be removed without entering the venous compartment. The oculomotor and trochlear nerves were accompanied by an arachnoidal and dural sheath. The oculomotor nerve sheath stopped under the anterior clinoid process in baboons. The trigeminal ganglion was covered posteriorly with an arachnoid membrane and adhered firmly to the dura propria on lateral and anterior sections. The three branches of the trigeminal nerve had no arachnoid covering, except for arachnoid granulations in humans. In baboons, the oculomotor and trochlear nerves were thicker than in humans, while the ophthalmic nerve was thinner. The abducens nerve belonged to the lateral wall of the sinus in baboons and had no arachnoidal sheath except in the first millimeters of Dorello's canal. After leaving their arachnoidal and dural sheath, the intracavernous cranial nerves acquired a typical peripheral sheath. The venous channels in both species were true dural sinuses. Willis cords and adipose tissue were identified.

Abducens Nerve↗
PubMed1997

Microanatomy of the perforators of the anterior communicating artery complex.

We describe the microanatomy of the perforating arteries arising from the anterior communicating artery complex (5 mm distal of the anterior cerebral artery, the anterior communicating artery, and 5 mm proximal of the distal anterior cerebral artery). Thirteen unfixed human brains were used in this study. The origin and number of perforators are described, as is the site of brain penetration, and results are correlated with previous studies. The hemodynamics of blood flow in relation to the formation of an anterior communicating artery aneurysm and different surgical approaches are mentioned. The neuropsychological outcome after aneurysm clipping with regards to the pattern of blood supply from the anterior cerebral artery complex is also discussed.

Brain↗
PubMed1997

High power drill systems in neurosurgery.

Neurosurgical drill systems have evolved enormously over the centuries, from the early tools of trephination to the latest motor powered drills. The Midas Rex III Motor system and the Midas Rex driver motor are the newest systems, incorporating features that allow convenient operation by surgeons.

Craniotomy↗
PubMed1997

Aneurysm clips: magnetic quantification and magnetic resonance imaging safety. Technical note.

Knowledge of the magnetic properties of cerebral aneurysm clips in patients undergoing magnetic resonance (MR) imaging is imperative. The authors quantified in electromagnetic units the magnetic properties of 13 different types of aneurysm clips by using a vibrating sample magnetometer. Their results showed that the magnetic moment of these clips ranged from 0.15 EMU/g to as high as 152.7 EMU/g. Based on these results and tests of the movement of the clips during MR imaging, they conclude that aneurysm clips with a magnetic moment less than 1 EMU/g may be safely used during MR imaging. The quantification of magnetic properties into electromagnetic units by using a vibrating sample magnetometer is a reliable method applicable to any testing field gradient. This method can be used as a standard to measure and label the magnetic properties of aneurysm clips.

Aneurysm↗
PubMed1997

Embolization of the nidus of brain arteriovenous malformations with n-butyl cyanoacrylate.

OBJECTIVE: To demonstrate that nidus embolization of brain arteriovenous malformations (AVMs) with Histoacryl (B. Braun, Melsungen, Germany) is effective and yields low morbidity and mortality rates. METHODS: We present a retrospective analysis of 54 brain AVMs treated at the University of Illinois at Chicago from April 1994 to December 1995. Treatment modalities included embolization in all cases and then surgical resection or radiosurgery. INSTRUMENTATION: The nidus was reached with the combined use of a Magic microcatheter (Balt, Montmorency, France) and a Terumo 0.010-inch guidewire. TECHNIQUE: Embolization was performed only when the tip of the microcatheter was wedged into the nidus of the AVMs with no reflux of contrast proximally. The embolization was performed using simultaneous biplane roadmapping with the patient under general anesthesia without Amytal testing. RESULTS: Twenty-six of 54 patients are still waiting for more radical treatment. Two deaths and two minor and one severe permanent neurological deficit occurred. Three patients were cured with embolization alone; 11 patients were cured after surgical resection. Three patients underwent radiosurgery, with one cure after 1 year. CONCLUSION: Nidus embolization with Histoacryl is an effective technique that permits complete cure of a large number of brain AVMs, with or without surgical resection and/or radiosurgery.

Adolescent↗
PubMed1997

Arteriovenous malformation nidus catheterization with hydrophilic wire and flow-directed catheter.

Arteriovenous malformation nidus catheterization with a flow-directed catheter at times can be difficult owing to tortuosity of the intracranial vasculature and distal location of the nidus. Since January 1995, hydrophilic wire has been used in conjunction with the 1.8F flow-directed microcatheter in over 150 vessel embolizations with cyanoacrylate glue for brain and spinal arteriovenous malformations at our institution. This technique has improved our success rate in achieving superselective catheterization of the nidus and has shortened the overall procedure time. To date, only one complication has occurred that was directly related to wire manipulation.

Adult↗
PubMed1996

Transcranial cerebral oximetry in endovascular treatment of carotid-cavernous fistula.

The transcranial cerebral oximeter is a reliable, low-cost, noninvasive device that provides real-time evaluation of regional brain oxygen saturation during endovascular treatment of cerebrovascular diseases. We discuss three patients with carotid-cavernous fistulae treated by endovascular balloon occlusion, each monitored continuously before, during, and after the procedure with transcranial cerebral oximetry. The cerebral oxygen saturation measured was directly related to the side of the venous drainage of the fistula, being 15-20% higher on that side. Following endovascular occlusion of the fistula, oxygen saturation gradually became equal on the two sides.

Adult↗