Howard Yonas

University of New Mexico

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Co-Authors

Edwin M. Nemoto

University of New Mexico

David Gur

University of Pittsburgh

Sidney K. Wolfson

University of Nebraska Medical Center

Charles A. Jungreis

Health and Education Research Management and Epidemiologic Services (United States)

Ronda R. Pindzola

University of Pittsburgh

Richard E. Latchaw

University of California Davis Medical Center

Joseph M. Darby

University of Pittsburgh

Laligam N. Sekhar

Neurological Surgery

Lawrence R. Wechsler

Hospital of the University of Pennsylvania

Andrew D. Firlik

Foundation Medical Partners

Cooperative Institutions

Neurological Surgery

206

University of Pittsburgh

196

University of Pittsburgh Medical Center

108

UPMC Presbyterian

University of Pennsylvania

Harvard University

University of New Mexico

University of Washington

Thomas Jefferson University

University of Virginia

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Ischemic threshold in human stroke: CBF correlation with stroke volume

Journal of Stroke and Cerebrovascular Diseases (1997)

Andreas M. Kaufmann AD Firlik Howard Yonas

Stroke

10.1016/s1052-3057(97)80064-x

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Citations (0)

Intraoperative Urokinase Infusion for Embolic Stroke during Carotid Endarterectomy

Neurosurgery (1995)

John D. Barr Michael Horowitz John M. Mathis Robert J. Sclabassi Howard Yonas

Embolic stroke is an infrequent complication of carotid endarterectomy. Somatosensory evoked potential monitoring detected delayed acute neurological deterioration during endarterectomy performed on a 71-year-old woman. Intraoperative arteriography performed via an indwelling shunt revealed thrombus within the middle cerebral artery and distal branches. A microcatheter was placed into the internal carotid artery via the arteriotomy and advanced into the middle cerebral artery. Urokinase was infused into and around the thrombus until almost complete thrombolysis had been achieved. The patient recovered quickly and was discharged without neurological deficit.

Arteriotomy

Stroke

Endarterectomy

10.1227/00006123-199503000-00024

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Citations (26)

Xenon/CT in the Management of Traumatic Brain Injury

The Open Neurosurgery Journal (2010)

Andrew P. Carlson Howard Yonas

Xenon/CT provides quantitative CBF data that has a proven record of being both safe and prognostic for deci- sion making. The technique itself has been extensively validated. Modern equipment has allowed for integration of the data into immediate bedside decision-making with the use of a portable head CT scanner and improved data processing. The use of xenon/CT in decision making in traumatic brain injury may have a high utility in determining whether a spe- cific treatment— whether it is hyperventilation, induced hypertension, or other intervention—is in fact helpful to the indi- vidual patient. This can allow for decision making based on an individual patient's physiology rather than generalized guidelines which may, in some cases, even be harmful.

Deci-

Source

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CT-Based Assessment of Acute Stroke: CT, CT Angiography, and Xenon-Enhanced CT Cerebral Blood Flow

Stroke (2001)

Megan M Kilpatrick Howard Yonas Steven A. Goldstein Amin Kassam James Gebel

Only a small percentage of acute-stroke patients receive thrombolytic therapy because of time constraints and the risks associated with thrombolytic therapy. We sought to determine whether xenon-enhanced CT (XeCT) cerebral blood flow (CBF) and/or CT angiography (CTA) in conjunction with CT can distinguish subgroups of acute ischemic stroke victims and thereby better predict the subgroups most likely to benefit and not to benefit from thrombolytic therapy.An analysis of 51 patients who had a CT, CTA, and stable XeCT CBF examination within 24 hours of stroke symptom onset was conducted. These initial radiographic studies and National Institutes of Health Stroke Scale score on admission were assessed to determine whether they could predict new infarction on follow-up CT or discharge disposition by use of the Fisher exact test to determine statistical significance.Patients with no infarction on initial CT and normal XeCT CBF had significantly fewer new infarctions and were discharged home more often than those with compromised CBF. The same held true for patients with an open internal carotid artery and middle cerebral artery by CTA and normal CT compared with those with an occluded internal carotid artery and/or middle cerebral artery by CTA. Either was superior to CT and the National Institutes of Health Stroke Scale in prediction of outcome. Both enable the selection of a group of patients not identifiable by CT alone that would do well without being exposed to the risks of thrombolytic therapy. This study included too few patients to statistically assess the role of combining CTA and XeCT CBF information.The combination of CT, CTA, and Xe/CT CBF does define potentially significant subgroups of patients. The utility of this classification is supported by the observation that CTA and XeCT CBF are superior to CT alone in predicting infarction on follow-up CT and clinical outcome. This information may be useful in selecting patients for acute-stroke treatment.

Acute stroke

Stroke

10.1161/hs1101.098330

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Citations (55)

Xenon/CT cerebral blood flow studies during continuous depth electrode monitoring in epilepsy patients.

David W. Johnson Jeffery P. Hogg Richard M. Dasheiff Howard Yonas Susan Pentheny

PURPOSE To observe and describe cerebral blood flow (CBF) alterations immediately following depth electrode stimulation of the temporal lobe in patients with medically intractable epilepsy. MATERIALS AND METHODS Five patients with partial epilepsy undergoing presurgical evaluation were chosen for xenon/CT cerebral blood flow (Xe/CT CBF) measurement immediately following electrically stimulated seizures via stereotactically placed temporal lobe depth electrodes. Each patient had a baseline Xe/CT CBF study. Four of the five patients had a total of seven temporal lobe stimulations each followed by a Xe/CT CBF study. The other patient had right temporal lobe electrical status epilepticus and was scanned without stimulation or electroencephalogram monitoring. RESULTS Of the four baseline or interictal scans, no areas of abnormally low flow were detected, but one baseline scan had elevated flows of 115 mL.100 g-1.min-1 in the left temporal lobe. One stimulation elicited 8 seconds of afterdischarge potentials, but no alteration of CBF was detected. One stimulation elicited an aura but no electrographic seizure was detected. This resulted, however, in bitemporal lobe elevation of CBF. The other five temporal lobe stimulations resulted in 17-63 seconds of afterdischarge potentials and all resulted in elevation of CBF to 69-118 mL.100 g-1.min-1. One of these five stimulations resulted in seizure and localized elevation of CBF. Following seizure activity, elevated CBF began to return to baseline levels by 20 minutes. CONCLUSION This study reveals a direct spatial and temporal relationship of elevated CBF with seizures. This study provides the most direct data to date in human subjects that focal seizure activity elevates CBF. Since seizures are known to increase metabolic activity in the activated tissue, this data also supports the assumption of coupling between CBF and metabolism during the pathologic process of a seizure.

Electrocorticography

Frontal lobe

Lobe

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Citations (17)

Comparison of Xe/CT and133 Xe CBF in Severe Head Injured Patients

Critical Care Medicine (1998)

ME Kerr Andrew Kofke Z Gur Howard Yonas Walter D. Obrist

Society of Critical Care Medicine; 27th Educational and Scientific Symposium; San Antonio, Texas, USA; February 4-8, 1998: Poster Hall: Thursday, February 5, 1998 5: 45-7: 15 pm; Friday, February 6, 1998 11: 40 am-1: 00 pm; Saturday, February 7, 1998 11: 40 am-1: 00 pm: Poster Presentations: Nursing

Thursday

10.1097/00003246-199801001-00231

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Citations (0)

Effect of low concentration stable xenon on the EEG power spectrum

Electroencephalography and Clinical Neurophysiology (1987)

Robert J. Sclabassi Raymond M. Lofink A. N. Guthkelch David Gur Howard Yonas

10.1016/0013-4694(87)90122-2

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Citations (7)

CEREBROVASCULAR RESPONSES TO VASOPRESSORS BEFORE AND AFTER SUBARACHNOID HEMORRHAGE (SAH) ASSESSED BY XE/CT IN MONKEYS.

Journal of Neurosurgical Anesthesiology (1995)

Edwin M. Nemoto Howard Yonas Anthony M. Kaufmann Charles A. Jungreis R. Klementavicius

NEMOTO, E. M. Ph.D.; YONAS, H. M.D.; KAUFMANN, A. M.D.; JUNGREIS, C. M.D.; KLEMENTAVICIUS, R. M.D. Author Information

10.1097/00008506-199510000-00051

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Citations (0)

Basal Q10 for Cerebral Metabolic Rate for Oxygen (CMRO2) in Rats

Advances in experimental medicine and biology (1996)

R. Klementavicius Edwin M. Nemoto Howard Yonas

Q10

Basal (medicine)

10.1007/978-1-4613-0333-6_23

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Citations (3)

Pentothal Protection for Delay Cerebral Revascularization

Howard Yonas Manuel Dujovny Ruth Segal D. Nelson

Thiopentone (20 mg/kg/bolus and 20 mg/kg/three hours) was effective in preventing infarction in five dogs with six hours of middle cerebral occlusion. Nine control animals sustained massive to large infarctions. Utilizing this regime therapeutic blood levels were rapidly attained for over 12 hours without side effects. From the experimental and human experience with focal cerebral ischaemia, there appears to be a finite grace period in which cerebral revascularization can be undertaken. In canine and primate models this time has been about five hours, following which the infarction process may not be reversible (Sundt et al. 1977, Laha et al. 1978). Seeking to prolong this grace period, thiopentone was selected as an ideal drug for this purpose, and its effect on the revascularized canine middle cerebral distribution was evaluated at six hours following embolectomy.

Bolus (digestion)

Embolectomy

10.1007/978-3-7091-4088-8_57

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Citations (4)