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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among 20 patients with symptoms of cerebrovascular insufficiency, dissociation between memory disturbances and cognitive functions, and PEG studies, there were 13 cases showing atrophy of the hippocampus. The neurological and psychological studies included memory functions tests, IQ, and the analysis of language and praxia. Complementary tests included standard EEG records, EEGs obtained with nasopharingeal electrodes and PEG tomography with selective filling of both temporal horns, in order to demonstrate the inner and lower surface of the temporal lobes. The volume of the Ammon horn was reduced in 13 cases. Hippocampal atrophy was unilateral in 11 patients and bilateral in 2. The fact that hippocampal atrophy was demonstrated by PEG studies in 13 out of 20 cases, appears to be highly significant. This clinico-neuroradiological correlation seems to indicate that hippocampal atrophy, following ischemia in the deep distal vertebro-basilar-posterior cerebral territory, disturbs the function of axial structures (Papez circuit or limbic system) apparently leading to the disturbances of memory functions observed in this group of patients.
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PMID:[Atrophy of the hippocampus of vascular origin. Clinico-pneumoencephalographic study]. 58 22

Cerebrovascular insufficiency arises from multiple causes, including cardiovascular insufficiency and local obstacles to the blood flow in the "four brain vessels". These obstacles are caused by primary thrombosis, by embolism, or by stenosing or ectatic arteriosclerosis. As there are anastomoses in the extra- and intracranial vessels, a collateral circulation can arise when hemodynamic conditions (blood pressure etc.) are adequate; this is also necessary for the preservation of these collaterals in later stages. Since particular hemodynamic conditions (terminal and watershed zones) have particular roles, different patterns of infarction can arise. Local obstacles to the blood flow can be subjected to vascular surgery as a preventive measure or even for vital conditions. The details of cerebral blood flow and brain viability have not become completely clear from the results of modern experimentation. The setting up of research institutes to concentrate on arteriosclerosis and ischemia in collaboration with clinical centers devoted to coronary and cerebral infarction seems to be very necessary.
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PMID:[Cerebrovascular insufficiency (author's transl)]. 120 96

The role of surgical therapy for Takayasu arteritis remains controversial. From 1973-1991, 23 patients with Takayasu arteritis have been treated at the University of Southern California. Twelve patients have required 17 arterial reconstructions for symptomatic complications of arterial disease refractory to medical therapy. Indications for operation have included renovascular hypertension (7), extremity ischemia (5), cerebrovascular insufficiency (2), dilated ascended aorta with aortic insufficiency (1), thoracic aortic aneurysm (1), and abdominal aortic aneurysm (1). Long-term clinical follow-up has demonstrated uniform symptomatic improvement. Fifteen of seventeen arterial reconstructions are still patent. Surgical treatment of symptomatic Takayasu arteritis is highly effective. Excellent long-term graft patency can be expected following arterial reconstruction.
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PMID:Surgical treatment of Takayasu arteritis. 136 Sep 62

Takayasu's arteritis is an inflammatory arteriopathy that often progresses to obliteration of multiple large arteries. Variable results have been reported after medical and surgical management. Twenty female patients with Takayasu's arteritis were treated from 1973 to 1989. Eleven (55%) patients had hypertension. Upper or lower extremity ischemia was present in 12 (60%) patients and cerebrovascular insufficiency in seven (35%). Nine patients initially managed with corticosteroids had no improvement in signs or symptoms of arterial insufficiency. Eleven patients had 16 vascular procedures for the following indications: renovascular hypertension (6), extremity ischemia (5), cerebrovascular insufficiency (2), dilation ascending aorta with aortic insufficiency (1), thoracic aortic aneurysm (1), abdominal aortic aneurysm (1). Procedures included aortorenal bypass (5), carotid-subclavian, axillary, or brachial bypass (4), aorto-carotid bypass (2), aneurysm resection (2), supra-celiac aorto-femoral bypass (1), ascending aorta/aortic valve replacement (1), and nephrectomy (1). Clinical improvement occurred in all patients. There were no operative deaths. All are alive at a mean follow-up of 5.75 years (6 months to 16 years). Revision of the initial reconstruction has been required for recurrent renovascular hypertension in one patient and extremity ischemia in another. The other nine patients remain symptomatically improved. Symptomatic Takayasu's arteritis frequently requires arterial reconstruction. Symptomatic improvement and excellent long-term graft patency can be expected after arterial reconstruction.
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PMID:Surgical procedures in the management of Takayasu's arteritis. 197 28

Seven hundred forty-eight carotid endarterectomies were performed on 592 patients with cerebrovascular insufficiency during a 13-year period. Overall operative procedure mortality was 2.7%. In the last 6 years, using a shunt routinely and avoiding operation on acute strokes, mortality was 1.47%. In frank strokes it was 3.7%; in transient ischemia, 0.77%; and zero for chronic ischemia and asymptomatic bruits. Incidence of operation-related deficits among transient ischemia and asymptomatic bruit patients was 0.9% for transient weakness and 2% for permanent deficits. Of 172 long-term deaths, 23 were due to cerebral causes, or 3.9% of the entire series. Among frank stroke survivors, 30.2% are normal and 58.7% improved. In transient ischemia survivors 81% are normal and 15.7% improved. In 65 asymptomatic bruit patients operated upon electively, two had strokes during follow-up, one mild and one severe. Among 37 asymptomatic bruit control patients, 24 or 65% developed symptoms of transient ischemia or frank strokes. Of 118 totally occluded carotid arteries explored, flow was restored in 48 (40.7%) but could not be restored in 70 (59.3%). For cerebral protection during carotid endarterectomy the routine use of a temporary inlying bypass shunt with general anesthesia is advocated for all partial occlusions. Endarterectomy is most useful for transient ischemia and selected patients with mild frank strokes and asymptomatic bruits. Acute profound and rapidly progressing strokes should not be operated upon as an emergency, but allowed to stabilize for several weeks and then be considered for possible operation.
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PMID:Carotid endarterectomy for cerebrovascular insufficiency: long-term results in 592 patients followed up to thirteen years. 395 99

In a 20-year period from 1961 to 1981 at the University of Kentucky Medical Center, there were 20 patients with vascular lesions directly attributable to irradiation. Two distinct patterns of arterial injury attributable to radiotherapy were identified--arterial disruption and occlusion. Arterial disruption occurred in 12 patients--11 carotid blowouts and 1 iliac artery rupture. Two patients underwent prophylactic carotid artery ligation for impending rupture. In the 11 carotid artery ruptures, ligation of the artery in nine patients resulted in stroke or death in five patients. Iliac artery disruption necessitated ligation, which eventually led to severe ischemia requiring hip disarticulation. Unusual arterial stenosis or occlusion occurred in six patients 7 to 24 years after irradiation. Three patients had severe stenosis or occlusion of the common, internal, or external carotid arteries leading to cerebrovascular insufficiency. Three other patients with focal stenosis of the iliofemoral region were successfully treated with bypass grafting.
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PMID:Radiation-induced arterial injuries. 682 69

Brain blood flow may be compromised as severely by altered cardiovascular dynamics as by atherosclerotic flow-limiting lesions in carotid arteries. The Automated Physiologic Profile can distinguish between those clinically important mechanisms. The Automated Physiologic Profile is a concept and method and apparatus. Physiologic performance of the heart, vascular tone in systemic and pulmonary vessels, and oxygen consumption are derived and printed on a standard report form. This easy to use form identifies mechanisms and illustrates severity of patho-physiologic aberrations contributing to ischemia-inducing processes. Serial portrayal depicts effectiveness of therapeutic interventions. This report included examples of APP in patients with ventricular rhythm disturbance, sick sinus syndrome, hypovolemic low cardiac out-put, and carotid artery stenosis as contributing factors in clinical cerebrovascular insufficiency. All were accompanied by excessive systemic arteriolar resistance, implying reduced brain blood flow. Serial APPs correlated with clinical events in the case histories.
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PMID:Automated physiological profile assessment of effects of altered cardiovascular dynamics on brain blood flow. 730

The hippocampal formation and its cholinergic input are an important neurobiological substrate for learning and memory processes. Since alterations in learning and memory are a common consequence of toxicant exposure it is possible that the hippocampus is an important target site for neurotoxicity. In fact, the hippocampus has been shown to be preferentially susceptible to a wide variety of toxic insults. For example, the hippocampus is damaged by environmental toxicants such as heavy metals, drugs of abuse such as alcohol and by cerebrovascular insufficiency finally resulting in hypoxia. The NMDA subtype of glutamatergic receptor plays a major role in learning and memory and in excitoxicity secondary to ischemia, hypoglycemia and trauma. The nature of the adverse effects of neurotoxins at this receptor site may be linked to the neurobiological characteristics that make this structure uniquely susceptible to toxic insult.
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PMID:Neuropathology of the hippocampus and its susceptibility to neurotoxic insult. 785 77

Middle aged rats (13 months) were subjected to chronic cerebrovascular insufficiency (CVI) for 9 weeks using a 3-vessel occlusion technique. This CVI injury targets CA1 neuron damage selectively. Three groups of rats had their cerebral blood flow restored after 1, 2 or 3 weeks following CVI by removal of their carotid artery occluders. Another rat group did not undergo deocclusion for the 9 week observation period. Rats were tested for memory acquisition and retention 6 and 9 weeks after CVI using a modified water maze test. At the end of the 9 weeks, cerebral blood flow was measured in the fronto-parietal cortex and rats were killed by fixation-perfusion. Hippocampal morphometry was done to assess the % of damaged CA1 neurons and the density of GFAP-positive hyperplasia and hypertrophy. Results show that restoration of cerebral blood flow 1 and 2 weeks after CVI but not after 3 weeks of CVI, reversed a significant increase in reactive astrocytosis and prevented memory impairment in these deoccluded rats when compared to the non-deoccluded group. It appears from these results that 'neuronal rescue' of CA1 neurons is possible when cerebral blood flow is restored in rats subjected to chronic CVI during a 2 week (but not 3 week) 'window of opportunity'. This chronic brain ischemia model may be useful in screening potential therapy in patients with dementia where spatial memory impairment and hippocampal damage may be manifested.
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PMID:Brain blood flow restoration 'rescues' chronically damaged rat CA1 neurons. 822 Oct 94

Cerebral infarction is the result of cerebrovascular insufficiency and itself creates complex changes in cerebral hemodynamics. To allow recognition of patterns of change in regional cerebral blood flow (r-CBF) caused by cerebral infarction, the authors present an atlas of Tc-99m hexamethylpropyleneamine oxime (Tc-99m HMPAO) SPECT brain scan sections for a variety of strokes demonstrating typical vascular territorial involvements and evolution of morphologic and r-CBF change. Sections from MRI or CT are shown with SPECT images of the stroke lesion for comparison of the complementary information provided by regional cerebroperfusion and by morphology. Examples of SPECT during acute, subacute, and chronic stages of stroke are provided. To illustrate the temporal evolution of stroke and accompanying changes in the "stroke penumbra," case examples of acute tissue necrosis, luxury perfusion, ischemia, and diaschisis are presented. Methods for semiquantitative analysis of morphologic versus r-CBF defect size after acute stroke are described. How brain SPECT scans conducted during Diamox initiated cerebrovascular stress tests can complement the information obtained from baseline studies and assist in the interpretation of r-CBF abnormalities is also demonstrated.
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PMID:Regional cerebral blood flow changes in stroke imaged by Tc-99m HMPAO SPECT with corresponding anatomic image comparison. 829 29


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