bluuebunny/crossref_metadata_2025 huggingface dataset:
Components of blood pressure and risk of atherothrombotic brain infarction: the Framingham study.
Authors: Kannel W B , Dawber T R , Sorlie P , Wolf P A
Published: June 2011

From a study of the evolution of atherothrombotic brain infarction (ABI) in the Framingham cohort of 5,209 men and women over 18 years of follow-up, it has been ascertained that hypertensionis the most common and most powerful precursor. Atherothrombotic brain infarction developed in hypertensive patients seven times more often than in normotensive patients, and the risk was proportional to the blood pressure throughout its range.
Hemodynamic Derangement for the Induction of Cerebrovascular Fat Deposition in Normotensive Rats on a Hypercholesterolemic Diet
Authors: YAMORI YUKIO , HORIE RYOICHI , SATO MASAYASU , FUKASE MASAICHI
Published: June 2011

Cerebrovascular ring-like fat deposition, which was noted only in hypertensive rats but never observed in normotensive rats even after they had been fed a high-fat cholesterol (HFC) diet for a long time, was successfully developed in the posterior communicating or other cerebrobasal arteries in normotensive rats fed an HFC diet for ten weeks after bilateral or unilateral carotid artery ligation or basilar artery ligation. These posterior communicating arteries with fat deposits were clearly dilated to a significant extent. These findings corroborated the fact that not only high blood pressure but also hemodynamic derangements induced by hypertension or other causes were important factors for the development of fat deposition in cerebral arteries.
Fibromuscular dysplasia and multiple dissecting aneurysms of intracranial arteries. A further cause of Moyamoya syndrome.
Authors: Pilz P , Hartjes H J
Published: June 2011

A 16-year-old boy, who had sudden left-sided hemiplegia, died two weeks following onset of symptoms. A right carotid angiogram showed stenosis at the termination of the internal carotid artery. The middle cerebral artery had a beaded appearance and some of its branches were occluded. A basal "moyamoya" syndrome and transdural anastomoses were present. At autopsy, multiple intracranial dissecting aneurysms were found. Arteries of the body displayed fibromuscular dysplasia (FMD). The relevance of dysplastic changes of intracranial arteries and the relationship to moyamoya syndrome are discussed.
Flow and compartmental weight in relation to the cours of stroke.
Authors: Heiss W D , Zeiler K , Turnheim M , Podreka I
Published: June 2011

Using a scintillation camera system, hemispheric and regional cerebral blood flow was measured repeatedly during the course after a stroke. In 20 patients who improved clinically mean hemispheric and regional flow and relative weight of rapidly perfused compartment increased, while these values decreased in 15 patients, on an average, whose clinical condition deteriorated or did not change. The changes of flow and relative weight were significantly different between the two groups. Futhermore, the relationship between changes in clinical condition, scored according to a rating scale, and changes in flow and compartmental weight was proved by significant Spearman rank correlation coefficients. In six cases hyperperfused areas in locations of disturbed neurological function were observed; these areas were found to be ischemic at measurements done early and late in the cours after the stroke. This type of hyperperfusion was related to beneficial prognosis. The results indicate a shift of tissue form fast to slowly cleared compartment after a cerebrovascular attack. If tissue morphology is not entirely destroyed, recovery might occur; this results in an increase of recorded weight of rapidly clearing compartments, which correlates to the clinical course.
Cerebral atherosclerosis in Uganda.
Authors: Owor R , Resch J A , Loewenson R B
Published: June 2011

A study of arterial circles of Willis from a series of 715 consecutive autopsies in Ugandan Africans shows that severity of cerebral atherosclerosis increases with age. No significant difference exists between men and women nor among main tribal groups. The severity is less in Ugandan Africans than in United States blacks but is approximately the same in United States Caucasians. However, the Ugandan Africans show a more severe cerebral atherosclerotic involvement than do the Nigerians.
Platelet aggregability measured by screen filtration pressure method in cerebrovascular diseases.
Authors: Kobayashi I , Fujita T , Yamazaki H
Published: June 2011

Platelet aggregability was measured using the screen filtration pressure (SFP) method in 50 elderly healthy people, 93 persons with essential hypertension, 166 patients with cerebral thrombosis at the recovery stage (more than two months after onset), and 74 patients with cerebral hemorrhage at the recovery stage. SFP by 3 muM ADP in the healthy persons, the hypertensive patients, and the patients in the recovery stages of hemorrhage and thrombosis were 148.7 +/- 53.5, 176.2 +/- 74.4, 189.8 +/- 58.3 and 206.3 +/- 58.9 mm Hg, respectively. The differences of the SFP between the Healthy and each of the diseased groups were statistically significant (P less than 0.01 to 0.05). Meanwhile, SFP of nine patients with cerebral thrombosis and 18 patients with hemorrhage was measured during their time course of disease from the onset to 180 days. SFP in the acute stage of thrombosis showed an increase and a gradual decrease during the time course, while SFP in the acute stage of hemorrhage showed the opposite -a decrease and a gradual increase. A statistically significant difference was observed between both groups within 30 days from onset (P less than 0.001). Screen filtration pressure in the acute stage of hemorrhage showed 95.2 +/- 17.7 mm Hg in nine survival cases and 194.0 +/- 96.2 mm Hg in nine deaths with ten days from the onset. The difference was statistically significant (P less than 0.001). Such results suggest a role of platelets in cerebral thrombosis and hemorrhage and a usefulness in differential diagnosis of both diseases.
Patterns of Changes of Blood Flow and Relationships to Infarction in Experimental Cerebral Ischemia
Authors: HEISS WOLF-DIETER , HAYAKAWA TORU , WALTZ ARTHUR G.
Published: June 2011

Regional cerebral blood flow (CBF) was measured in both middle ectosylvian gyri of ten cats by recording the clearance of molecular hydrogen (H
2
) with implanted polarized electrodes 125 µ in diameter, before and up to seven days after occlusion of the left middle cerebral artery (MCA) with a device implanted in the intact cranium. Five patterns of changes of CBF were recorded with the leftsided electrodes. In eight cats MCA occlusion caused immediate decreases of CBF; in the other two cats CBF values were lowest two days after occlusion, presumably because of ischemic edema. Both persistent severe ischemia and early spontaneous postischemic hyperemia were associated with severe neurological deficits, marked swelling of the left cerebral hemispheres, and large infarcts. Late postischemic hyperemia was associated with less severe deficits, less swelling, and smaller infarcts, but the least severe deficits and smallest infarcts were noted in association with persistent moderate ischemia. No consistent patterns were recorded with the rightsided electrodes in this study. Hyperemia which develops spontaneously or is induced shortly after the onset of cerebral ischemia potentially may be harmful because of secondary increases of cerebral edema.
Acute gastric changes in patients with acute stroke. Part 2: gastroendoscopic findings and biochemical observation of urinary noradrenalin, adrenalin, 17-OHCS and serum gastrin.
Authors: Kitamura T , Ito K
Published: June 2011

To investigate the relationships between gastric change accompanying patients with acute stroke and the function of the autonomic nervous system and pituitary-adrenal system, studies on the gastroendoscopic technique and biochemical observations were done in 122 patients. The mean urinary noradrenalin and adrenalin excretions were elevated in patients with acute gastric changes, especially in patients with multiple erosions and acute ulcers. An elevation of the mean fasting serum gastrin concentration was found in patients with acute ulcers and no acute gastric changes. The mean urinary 17-OHCS excretion was increased in patients with multiple erosions, petechiae and acute ulcers. In conclusion, the sympathetic and parasympathetic nervous system and the pituitary-adrenal system have respectively different roles in the production of various types of acute gastric changes in patients.
Sanguineous cerebrospinal fluid in recanalized cerebral infarction.
Authors: Irino T , Taneda M , Minami T
Published: June 2011

To clarify the causal relationship between spontaneous recanalization of the occluded cerebral artery and development of hemorrhagic infarction, 15 patients with internal carotid or middle cerebral arterial axis occlusion were submitted to consecutive lumbar punctures and follow-up cerebral angiography. Consequently, six of seven recanalized patients had sanguineous cerebrospinal fluid (CSF) on the second or third day after ictus, while only one of eight non-recanalized patients had bloody CSF. It was strongly suggested that recanalization might have an initimate relationship with the development of hemorrhagic infarction.
Action of vasodilators on regional cerebral blood flow in subacute or chronic cerebral ischemia.
Authors: Capon A , De Rood M , Verbist A , Fruhling J
Published: June 2011

Regional cerebral blood flow (bicompartmental and stochastic method) was measured in a series of 20 patients with unilateral brain softening. Measurements were repeated during the administration of a vasodilator. A deterimental effect on the perfusion of the disease area was observed in the majority of cases. It has been shown that the chances for a vasodilator to decrease the perfusion in the diseased area were greater when the angiogram showed obstruction of an intracranial artery.
Radionuclide cerebral blood flow and carotid angiogram. Correlation in internal carotid artery disease.
Authors: Foo D , Henrickson L
Published: June 2011

Radionuclide cerebral blood flow (CBF) examinations of 48 patients with atherosclerosis, 18 with occlusion and 30 with stenosis of the internal carotid artery (ICA) were correlated with their respective cerebral angiograms. The following results were obtained. Flow was visually unilaterally diminished in 29 (60%) of 48 patients, including 14 (78%) with occlusion and 15 (50%) with stenosis. Sixty-two percent of the subjects with severe stenoses and 46% of the patients with mild stenoses had a positive flow study. Diminished flow was evident in the neck in 80% of the patients, intracranially in 20%. Positive radionuclide angiograms always pointed to the side with occlusion or the greater degree of stenosis even though bilateral interanl carotid disease was frequently found (54%). The data leading to the differentiation between major and minor ICA stenosis are not sufficient to justify any conclusion.
Cortical evoked potential and extracellular K+ and H+ at critical levels of brain ischemia.
Authors: Astrup J , Symon L , Branston N M , Lassen N A
Published: June 2011

As shown previously, the electrical function of the brain is critically dependent on cerebral blood flow in the sense that reduction beyond an ischemic threshold of approximately 15 ml/100 gm per minute (approximately 35% of control) in the baboon leads to complete failure of the somatosensory evoked response. This study tests the hypothesis that electrical failure in ischemia may be directly associated with a massive release of intracellular K+ or with a critical degree of extracellular acidosis. By microelectrode techniques, measurements of blood flow, extracellular activity of K+ and H+ as well as evoked potential were made in the baboon neocortex. Reductions in blood flow were obtained by occlusion of the middle cerebral artery and depression beyond the ischemic threshold of electrical function achieved by a reduction of systemic blood pressure which, in the ischemic zones, changed local cerebral blood flow proportionally. Abolition of evoked response could not be explained by depolarization by release of intracellular K+, nor was it critically dependent on cortical pH. However, the massive release of intracellular K+ was by itself critically dependent on cortical blood flow and occurred at 18 greater than 6 greater than 2 ml/100 gm per minute (median with 5% confidence limits). Thus a dual threshold in ischemia for neuronal function is described, the threshold for release of K+ being clearly lower than the threshold for complete electrical failure. Further, the findings support the concept of an ischemic penumbra during which the neurons remain structurally intact but functionally inactive. That neurons can survive for some time in this state of lethargy is evidenced by the observations that an increase in rCBF, if sufficient, can restore evoked potential and normalize extracellular K+ activity as well as pH.
133Xenon inhalation method. Analysis of reproducibility: some of its physiological implications.
Authors: Blauenstein U W , Halsey J H , Wilson E M , Wills E L , Risberg J
Published: June 2011

Regional cerebral blood flow (rCBF) was simultaneously measured at seven locations in each hemisphere by the Obrist 133Xenon inhalation method. In each of 35 healthy right-handed subjects two rest measurements were performed on consecutive days. The data analysis comprises the two-compartmentally derived parameters for flow (f1), relative tissue weight (w1), and fractional flow (FF1) respectively of the first compartment, and in addition the initial slope index (ISI). At each detector location the coefficient of variation (C.V.) of the change from first to second measurement was on average 10.4% (ISI), 14.2% (f1), 7.2% (w1), and 2.9% (FF1) respectively. However, when each regional measurement was expressed as a percentage of its hemispheric mean, the C.V. of the intermeasurement change was on average 4.4% (ISI), 7.0% (f1), 7.7% (w1), and 1.9% (FF1) respectively; that of the hemispheric means of ISI, f1, and FF1 was found to be distinctly larger, whereas that of w1 was about equal in size. The interhemispheric coefficient of variation for the change of the hemispheric means from first to second measurement was only 2.3% (ISI), 4.4% (f1), 1.6% (w1), and 1.1% (FF1) respectively. The findings suggest that (1) the variability of rCBF from subject to subject and in consecutive measurements in the same subject is to a substantial degree of physiological origin, and that (2) there are two determinants of rCBF which may operate independently: a determinant of the hemispheric mean level, probably a single determinant for both hemispheres, and a set of determinants for each separate regions superimposed on the hemispheric mean level.
Carotid ligation in gerbils. Influence of age, sex, and gonads.
Authors: Payan H M , Conrad J R
Published: June 2011

The ill effects of carotid artery occlusion or ligation vary in man and experimental animals according to surgical techniques, environmental conditions, diet, stress, sex, age, strain of the animal, blood pressure, the state of cardiopulmonary system, and other diverse factors. Unilateral carotid artery ligation in most small laboratory animals is an innocuous procedure. The gerbil, a desert rat, has been found to be quite sensitive to unilateral carotid artery ligation. The present experiments were designed to study the influence of age, sex, and castration on end results of the unilateral carotid artery ligation in gerbils. It appears that the young animals prior to sexual maturity and the sexually mature female are more resistant than the sexually mature male. This difference is assumed to be due to the influence of the gonads on the blood flow of the brain.
Stochastic analysis of 133xe clearance for determining regional cerebral blood flow in a primate model.
Authors: Agress H , Bacharach S L , Hammock M K , Green M V , Johnston G S , Di Chiro G
Published: June 2011

A technique for stochastic analysis of 133Xe washout using a computer-assisted Anger camera is described. The technique produces functional maps of both regional cerebral blood flow (rCBF) and error in rCBF. The calculational limitations of the technique are discussed and an experimental estimate made of the physical limitations associated with the low energy photon emitted by 133Xe. The method is demonstrated in a rhesus monkey model before and after surgical occlusion of the middle cerebral artery.
Experimental model for systematic study of impaired microvascular reperfusion.
Authors: Hallenbeck J M , Bradley M E
Published: June 2011

A technique is described for reliably producing quantifiable impairment of microvascular reperfusion of the brain after ischemia in dogs. The technique is derived from an analysis of the cerebrospinal fluid compression ischemia model as a Starling resistor. It is proposed that this model would be useful in systematic study of post-ischemic impairment of reperfusion.
Respiratory influence on the total and regional cerebral blood flow responses to intracranial hypertension.
Authors: Malik A B , Krasney J A , Royce G J
Published: June 2011

The effect of respiration on the cerebrovascular response to elevated intracranial pressure (ICP) was studied in anesthetized dogs. Total and regional cerebral blood flows were measured using labelled microspheres. In spontaneously breathing dogs total and regional cerebral blood flows increased when cerebral perfusion pressure was reduced to 20 mm Hg. The increase in regional flows was greater in the infratentorial areas than in the supratentorial areas. The increase in cerebral flow in spontaneously breathing dogs was associated with the development of hypoxemia and respiratory acidosis secondary to depression of ventilation. Elevation in ICP while regulating PO2, PCO2, and pH by controlled ventilation resulted in decrease in the total and regional cerebral blood flows. The decrease in regional flows was greater in the supratentorial areas. Induction of respiratory acidosis during elevated ICP in the controlled ventilated dogs with a 5% CO2 in air gas mixture, reversed the decrease in cerebral flows. The results suggest that the increase in cerebral blood flow during elevated ICP in spontaneously breathing dogs is secondary to the development of hypoxemia and respiratory acidosis since cerebral vessels retain responsiveness to increased PaCO2 when the vessels are dilated due to elevated ICP. The results also indicate that the regional cerebrovascular response to elevated ICP is non-uniform.
Coagulopathy following experimental cerebral ischemia.
Authors: Hossmann K A , Hossmann V
Published: June 2011

In adult normothermic cats cerebral blood flow was interrupted for 1 hour by clamping the innominate and subclavian arteries. Following ischemia the brains were recirculated with blood, and the coagulation system was investigated by measuring coagulation times and blood content of fibrinogen and platelets. Ischemia induced progressive consumption coagulopathy with an increase in coagulation times and a decrease of platelets and fibrinogen by more than 40%. Coagulopathy was accompanied by a respiratory distress syndrome with a significant increase in the alveolar-arterial carbon dioxide gradient from --3.3 to --13.5 mm Hg. A correlation was found between plasma fibrinogen concentration, cerebral blood flow and electrophysiological function, indicating that a relationship exists between the severity of postischemic coagulopathy and functional recovery following prolonged cerebral ischemia.
Monitoring of cerebral perfusion during anesthesia by time-compressed Fourier analysis of the electroencephalogram.
Authors: Myers R R , Stockard J J , Saidman L J
Published: June 2011

Time-compressed Fourier analysis of the electroencephalogram has proven to be a useful analytical procedure during anesthesia and surgery which simplifies data interpretation by presenting the EEG in a time-compressed frequency domain rather than the conventional time domain. This method of data analysis graphically accentuates the electroencephalographic correlates of ischemia-induced cerebral dysfunction and other cerebral oxygen consumption abnormalities. The ability to accentuate trends in frequency and power is derived from sequential plotting of spectra to produce a graph with three dimensional axes of frequency, time, and power. In carotid endarterectomies the system has proven more useful than the conventional EEG in assessing the need for a vascular shunt to maintain internal carotid flow during endarterectomy. In open-heart surgery time-compressed EEG spectral analysis has allowed early recognition of cerebral ischemia resulting from arterial hypotension and venous hypertension. Five cases are presented which demonstrate the ability of our system to reflect developing cerebral ischemia.
Analysis of vasoactivity of local pH, PCO2 and bicarbonate on pial vessels.
Authors: Kontos H A , Raper A J , Patterson J L
Published: June 2011

The mechanism by which the local effect of CO2ON pial arterioles is exerted was examined in anesthetized cats equipped with a cranial window for the direct observation of the microcirculation of the parietal cortex. The dilation of pial arterioles in response to application of artificial cerebrospinal fluid with low pH was the same whether or not the PCO2 of the solution was maintained in the normal range or markedly increased. The constriction of pial arterioles in response to application of artificial cerebrospinal fluid with high pH was the same whether or not the PCO2 of the solution was maintained in the normal range or markedly decreased. Finally, pial arterioles did not change their caliber in response to application of cerebrospinal fluid with unchanged pH but markedly increased or decreased Pco, or bicarbonate ion concentration. These results show that the action of CO2 on cerebral vessels is exerted via changes in extracellular fluid pH and that molecular CO2 and bicarbonate ions do not have independent vasoactivity on these vessels.
Dibutyryl cyclic adenosine monophosphate effects in the ischemic-hypoxic cat.
Authors: Sokoll M D , Stullken E H
Published: June 2011

The effects of dibutyryl cyclic adenosine monophosphate (dB-cAMP) were studied in fifty cats, twenty anesthetized with pentobarbital and thirty with halothane. Nasopharyngeal temperature and Paco2 were maintained at normal values. Somatosensory evoked response was monitored and used as an indicator of cerebral cortical function. Ischemic hypoxic injury was produced by an orthopedic tourniquet snugly applied around the animal's neck and inflated for a period of fifteen minutes. This method produces a reliable and reproducible injury. Times for recovery of the evoked response to 10% of control value, as well as immediate and long-term animal survival, were noted. The dBcAMP was administered at the end of the hypoxic insult. Treated animals recovered the evoked response earlier than the untreated controls and had better immediate and long-term survival rates.
Effect of carotid artery ligation on regional cerebral blood flow in normotensive and spontaneously hypertensive rats.
Authors: Choki J I , Yamaguchi T , Takeya Y , Morotomi Y , Omae T
Published: June 2011

Regional cerebral blood flow (rCBF) was measured in normotensive rate (NTR) and spontaneously hypertensive rats (SHR), in a lightly anesthetized state and with control of PaCO2 by artificial ventilation. Without carotid artery ligation, NTR and SHR showed almost identical rCBF values and distribution, despite significantly elevated levels of blood pressure in SHR. Bilateral carotid artery ligation, however, caused much more pronounced decreases of rCBF (ischemia) in SHR than NTR, in regions supplied by the carotid artery. The reduction of rCBF in SHR was rather homogenous and symmetrical. Mechanisms causing the differences between NTR and SHR are discussed.
Comparison of nerves to cerebral and extracerebral blood vessels: a differential effect of alpha methyl tyrosine on norepinephrine content.
Authors: Rosenblum W I , Chen M
Published: June 2011

Alpha methyl tryosine (AMT), and inhibitor of norepinephrine (NOR) synthesis, was injected intraperitoneally (200 mg/kg) in Sprague Dawley rats, kept in a cold room, or at room temperature for 16 hours. Using formaldehyde induced NOR fluorescence, nerve counts were made on whole mounts of cerebral and femoral arterioles 14-300 micronm in diameter, utilizing a grid superimposed on the vessels. Cold had no effect on the number of visible (i.e. fluorescing) nerves. AMT had an appreciable effect but only on nerves to femoral arterioles, where a significant reduction in nerve count was observed in both cold stressed and non stressed rates, when compared with animals not given AMT. Since the counting technique is sensitive only to large depletions of NOR, we cannot conclude that AMT failed to affect NOR content in cerebrovascular nerves. However, if such an effect was present, it was much less than the effect of AMT on nerves to femoral vessels. We suggest that the differential effect of AMT on these 2 vascular beds may indicate a lower basal level of NOR release from cerebrovascular nerves, which would correlate with the difficulty of demonstrating basal sympathetic tone in this vascular bed.
Sudden death from stroke.
Authors: Phillips L H , Whisnant J P , Reagan T J
Published: June 2011

Sudden death is defined as any death that occurs less than 24 hours after the onset of first symptoms. Strokes account for 10 to 20% of all sudden deaths. The records of all residents of Rochester, Minn., who had their first stroke during the period 1955 through 1969 were analyzed. Among 255 deaths caused by the first stroke, 52 were sudden. Twenty-six of the deaths were due to primary intracerebral hemorrhage, and 20 to primary subarachnoid hemorrhage. Only two of the sudden deaths were caused by infarction: one by pontine and cerebellar infarct and the second by a cortical infarct, which resulted in death from status epilepticus. Among the nine patients who died within 2 hours of the onset of symptoms, six had primary subarachnoid hemorrhage. Hypertension was noted in 23 of the 26 patients (88%) who died of primary intracerebral hemorrhage; 8 patients with primary intracerebral hemorrhage were on long-term oral anticoagulant therapy, and all 8 were hypertensive.
Brain water alterations after unilateral nephrectomy. A study of regional circulatory factors in squirrel monkeys.
Authors: Anderson D C , Jordan M M , Jacobson R L , Hayakawa T , Waltz A G
Published: June 2011

White and regional gray matter distributions of water, blood flow, and the protein tracer pertechnetate were measured in five normal squirrel monkeys. A second group of five monkeys, which had undergone unilateral nephrectomy six months previously, were found at the time of study to have blood pressures similar to those of the control animals but increased brain water and altered distribution of blood flow which was increased in white matter. No alteration of capillary permeability to the protein traces attended these changes, which appeared to be influenced by blood pressure. Nephrectomy without hypertension influences brain water content, perhaps because of an effect on cerebral resistance vessels. In hypertensive encephalopathy renal lesions, as well as intraluminal pressure changes, may be related to cerebral edema.
Relationship of transient ischemic attacks and angiographically demonstrable lesions of carotid artery.
Authors: Eisenberg R L , Nemzek W R , Moore W S , Mani R L
Published: June 2011

Eighty-eight percent of arteries in patients with amaurosis fugax or hemispheric transient ischemic attacks had angiographically demonstrable lesions at the carotid bifurcation. Eighty-one percent had stenoses or occlusions at the carotid bifurcation; 7 percent had ulcerative lesions without stenoses at this site. Forty-nine percent of arteries in these patients demonstrated ulcerative lesions with or without stenosis at the carotid bifurcation. There was no significant difference in the incidence or types of ulcerations between those patients with amaurosis fugax and those with hemispheric transient ischemic attacks. Eighty-eight percent of arteries examined in this series were amenable to surgical reconstruction. Amaurosis fugax and hemispheric transient ischemic attacks were of equal value in predicting the possibility of a surgically treatable lesion at the carotid bifurcation.
Report of Joint Committee for Stroke Resources. IV. Brain edema in stroke.
Authors: Katzman R , Clasen R , Klatzo I , Meyer J S , Pappius H M , Waltz A G
Published: June 2011

A classification of brain edema is provided as well as an extensive review of the animal models from which we have derived most of the basic information we have about the formation and resolution of edema. The clinical aspects of cerebral edema in stroke are discussed and also modern methods for identifying cerebral edema in the human. Attention is given to computed tomography and enhanced CT and advances in their application to this condition. Treatment of cerebral edema in the stroke patient using glycerol, dextran 40, mannitol, steroids, and other drugs is discussed and the need pointed out for controlled clinical trials of the therapeutic effectiveness of these agents.
Vascular endoscopy --- an adjunct to carotid surgery.
Authors: Towne J B , Bernhard V M
Published: June 2011

Technical advances in optical instrumentation have made vascular endoscopy a potential method for intraoperative evaluation of carotid endarterectomy. A prospective protocol was designed to evaluate the efficacy and practicality of this technique using the Hopkins Optical System in 35 carotid endarterectomies. The external carotid artery was examined after completion of the endarterectomy. The distal internal carotid artery was examined after removal of the shunt with all but 1 cm of the arteriotomy closed. Total time required for the procedure was less than 5 minutes in 21 cases and between 5 and 10 minutes in 14. Positive findings were noted in 71% of the external carotid endarterectomies which consisted of intimal flaps in 13 cases and intimal shreds in 25. In 2 patients (6%), internal carotid endoscopy revealed intimal shreds capable of embolizing and probably capable of causing a postoperative neurologic deficit. This technique permits a precise and complete evaluation of the vascular reconstruction.
Recurrent stenosis at site of carotid endarterectomy.
Authors: French B N , Rewcastle N B
Published: June 2011

Five patients studied by the authors and 28 mentioned in the literature indicate that recurrent stenosis occurs in no less than 0.6% of patients after carotid endarterectomy. The pathology of the recurrent stenosis was stated in only 10 cases indicating atherosclerotic disease in various stages of development in 7 and a fibrous intimal hyperplasia in 3. Correlation between risk factors for the development of atherosclerosis and the pathology of the recurrent disease was poor. Six patients developed recurrent disease despite postoperative prophylactic oral anticoagulation. Surgical technique appeared to have contributed to re-stenosis in 8 patients (1) by failure to remove the distal tongue of plaque or (2) narrowing of the lumen by the arteriotomy suture or (3) damage by a vascular clamp. In 18 symptomatic patients, 44% had symptoms by 3 years, 67% by 5 years, and 83% by 7 years after operation. The 8 patients with possible errors in surgical technique did not develop symptoms earlier than the other patients. Seventeen symptomatic patients had surgical correction of the re-stenosis (endarterectomy 9, vein patch 6, arterial homograft 1, not detailed 1). The incidence of recurrent stenosis after carotid endarterectomy is low and usually the operation provides a patent artery for life.
Modification of cerebral ischemic damage by anesthetics.
Authors: Lightfoote W E , Molinari G F , Chase T N
Published: June 2011

The yield of infarcted hemispheres following unilateral carotid ligation in gerbils under ketamine anesthesia substantially exceeded that occurring under pentobarbital anesthesia. In addition to increasing the gerbil stroke model's efficiency, ketamine provided a shorter recovery period, thus allowing earlier observation of clinical signs of brain injury. These results support the contention that anesthetic agents may modify the response of central neuronal tissues to acute ischemia.
Factors influencing outcome and length of stay in a stroke rehabilitation unit. Part 1. Analysis of 248 unscreened patients--medical and functional prognostic indicators.
Authors: Feigenson J S , McDowell F H , Meese P , McCarthy M L , Greenberg S D
Published: June 2011

A retrospective analysis of 248 patients with stroke (average age 67, range 17-98) admitted to a stroke rehabilitation unit over a sixteen month period showed that 80% of these patients were able to return home after an average length of stay (LOS) of 43 days. At discharge 85% of the group were ambulatory and 56% required no help in daily living activities. Severity of weakness on admission, long onset-admission intervals, the presence of severe perceptual or cognitive dysfunction or a homonymous hemianopsia in addition to a motor deficit were related to unfavorable outcome and increased LOS. The age of the patient, dysphasia or a hemisensory deficit in addition to weakness, or diabetes, hypertension, or ASHD were unrelated to the patients' functional status on discharge, discharge disposition, or LOS. Many patients with "unfavorable prognostic signs" made significant improvement after admission and were subsequently discharges. Thus, while the above findings may predict which patients can make maximal gains in a short term treatment facility, they also show that most patients, even those with "poor prognostic signs," can make enough functional improvement to be managed at home after a relatively short hospitalization.
Incidence of stroke in Frederiksberg, Denmark.
Authors: Hansen B S , Marquardsen J
Published: June 2011

Since 1971, stroke registers in several countries have been cooperating in a study of stroke epidemiology, initiated by WHO. One of the registers covers the population of Frederiksberg, Copenhagen. During the first two years of registration strokes were recorded in 556 Frederiksberg citizens. A certain diagnosis of cerebral hemorrhage--verified by angiography, spinal fluid examination, or autopsy--was made in 10% of the patients; subarachnoid hemorrhage was demonstrated in only 2%; most of the remaining patients probably had cerebral infarction. The overall annual incidence of stroke, when adjusted for age for the Danish population, was 1.9 per 1,000 for males, and 1.6 per 1,000 for females. For every type of stroke, except subarachnoid hemorrhage, the incidence increased markedly with age. The age-specific stroke incidence rates found in the present investigation are much lower than those demonstrated by Aho in a community-based study in Finland. In view of the strict comparability of the two studies, real differences in the risk of stroke may exist between the two communities.
Effects of combined parenchymal and vascular injury on platelet aggregation in pial arterioles of living mice: evidence for release of aggregate-inhibiting materials.
Authors: Rosenblum W I , El-Sabban F
Published: June 2011

Platelet aggregation was produced in pial arterioles by exposing them to appropriately filtered light from a mercury lamp, following intravascular injection of sodium fluorescein. The dye acted as a target for the radiant energy and initiated a sequence of events resulting in the platelet aggregation. The aggregates adhered to the vessel in which they first appeared. When a microneedle punctured the brain adjacent to a subsequently irradiated arteriole, platelet aggregation was inhibited, even though the arteriole was not touched by the microneedle. Inhibition was manifested by prolongation of the exposure time required for the light-dye stimulus to initiate an adherent aggregate and by lengthening the time required for the aggregate to grow and totally block erythrocyte flow in the affected vessel. It is suggested that a material(s) diffuses from the zone of brain puncture, to and through the arteriolar wall, with a resultant inhibition of aggregation. It is noted that the inhibiting effect is reduced as the distance between puncture and wall increases.
Experimental cerebral vasospasm after subarachnoid hemorrhage: development and degree of vasospasm.
Authors: Endo S , Suzuki J
Published: June 2011

Vasospasm of the basilar artery in 57 cats was induced by application of fresh blood, or a blood and cerebrospinal fluid (CSF) mixture incubated at 37 degrees C for 2 to 16 days. In animals treated with fresh blood or mixtures incubated for over 15 days, the severity of induced vasoconstriction is slight and duration short. Mixtures incubated 5 to 10 days induced severe and prolonged vasoconstriction. This incubation period for blood and CSF mixtures inducing severe vasospasm coincides with the developmental period of vasospasm after the onset of subarachnoid hemorrhage in our clinical experience. The prolongation of severe vasoconstriction induced by mixtures incubated for 7 days with clotted components is definitely greater than one induced by a mixture without clotted components. This experimental study suggests the existence of a vasospasmogenic substance in the blood in the subarachnoid space. Activity begins about 3 days after subarachnoid hemorrhage, increases strongly at 5 to 10 days, and disappears after 15 days.
Vascular spasm in cat cerebral cortex following ischemia.
Authors: Hart M N , Sokoll M D , Davies L R , Henriquez E
Published: June 2011

The reaction of brain parenchymal vessels in areas of no-reflow following ischemia in cats was evaluated. A method was devised by which brain biopsies following ischemia were quickly frozen at -170 degrees C, sections were cut and stained and vessel internal and external diameter measured. Vessels in the no-reflow areas had smaller internal and external diameters and thicker walls when compared to adjacent reflow areas as well as to normal control animals. By utilizing a 2-way analysis of variance in which reflow versus no-reflow vessel diameters were compared by region the differences were found to be statistically significant (p less than 0.05). The data raise the possibility that there may exist normal regional differences in the size of cerebral vessels.
133Xenon inhalation method: significance of indicator maldistribution for distinguishing brain areas with impaired perfusion. An index for total flow.
Authors: Blauenstein U W , Halsey J H , Wilson E M , Wills E L
Published: June 2011

This paper introduces a new index for the assessment of regional cerebral blood flow. The index is proportional to total flow, and is obtained from the ratio of regional count rate to arterial indicator input to a region. This index is a more sensitive indicator of impaired perfusion than the traditional flow rate indices which express flow per unit mass of tissue per minute. It accounts for brain tissue partly or totally deprived of its blood supply. Examples of clinical application are reported. A good correlation with the findings of computer-assisted tomography has been found.
Real time ultrasound tomography of the adult brain.
Authors: Smith S W , von Ramm O T , Kisslo J A , Thurstone F L
Published: June 2011

Initial clinical results are reported from a new real time, 2-dimensional ultrasound scanner modified for adult cephalic applications. An optimized transducer design and the use of the dynamically focused phased array imaging system have resulted in ultrasound tomograms of the brain which are significant improvements over previous attempts. Horizontal and coronal images of the ventricles, the corpus callosum and other midline structures are routinely displayed in a 45 degrees sector format. In addition, pulsating cerebral arteries are displayed in real time. Quantitative information can be obtained concerning cerebral vascular patency by using the selectable M-mode feature of this system. The results indicate that real time ultrasound tomography has potential for clinical application.
Cerebral protection with barbiturates: relation to anesthetic effect.
Authors: Steen P A , Michenfelder J D
Published: June 2011

The effect of racemic mephobarbital and its optical isomers on survival time of mice exposed to 5% O2 was studied. There was an increase in survival time from 4.2 minutes to 12.6 minutes for 100 mg/kg of the anesthetically active (-) isomer and the racemic form, but no increase for 100 mg/kg of the inactive (+) isomer. Since it has been shown that there is no difference in brain concentrations between the isomers, we conclude that the barbiturate protective effect is bound to the anesthetic effect. All mice convulsed, and since the non-anesthetized animals convulsed earlier and stronger than the anesthetized, it was possible that barbiturate protection was accounted for by its anticonvulsant effects. Diazepam 7.5 mg/kg, while reducing convulsions to the same degree as barbiturates without producing anesthesia, only increased survival time to 6.2 minutes. Thus, the barbiturate protective effect is distinct from the anticonvulsant effect. It seems to be bound to a stereospecific receptor for both protection and anesthesia.
Improved method for noninvasive measurement of regional cerebral blood flow by 133Xenon inhalation. Part I: description of method and normal values obtained in healthy volunteers.
Authors: Meyer J S , Ishihara N , Deshmukh V D , Naritomi H , Sakai F , Hsu M C , Pollack P
Published: June 2011

A clinical method for noninvasive measurement of regional cerebral blood flow (rCBF) and blood volume (rCBV) is described, based on Obrist's 10 minute, desaturation method after 1 minute inhalation of 133Xe. Sixteen collimated probes are placed over both hemispheres and brain stem-cerebellar regions. End-tidal 133Xe curves are used for correction of recirculation. KEV discriminators are set to record gamma and x-ray activity separately. Values are printed out automatically by a computer on a brain map. Extracerebral contamination is reduced by 1) computing curves from gamma activity, 2) applying pressure on the scalp beneath the probes, 3) 1 minute inhalation of 133Xe and recording desaturation curves for 10 minutes, thereby minimizing slow clearance from extracranial tissues. Normal values for both fast and slow compartments are reproducible and are in good agreement with the carotid injection method. The speech dominant hemishpere has higher flow than the right under conditions described. Posterior portions of the cranium over the cerebellum and brain stem appear to have higher flow gray values than the cerebral cortex. Gray matter flow decreases with advancing age.
Effect of ornithine alpha ketoglutarate (OAKG) on the response of brain metabolism to hypoxia in the dog.
Authors: Hares P , James I M , Pearson R M
Published: June 2011

Hypoxia is well known to cause an increase in brain anaerobic glycolysis. Ornithine alpha ketoglutarate (OAKG) given to six dogs was shown to attenuate these metabolic disturbances caused by hypoxia. Brain oxygen utilization was higher after ornithine alpha ketoglutarate during hypoxia than during a period of hypoxia alone. It is suggested that the clinical usefulness of OAKG should be explored in those situations where there is cerebral hypoxia or ischemia.
Effect of non-respiratory alkalosis on brain tissue and cerebral blood flow in rats with damaged blood-brain barrier.
Authors: Pannier J L , Weyne J , Demeester G , Leusen I
Published: June 2011

Acute alterations in plasma bicarbonate concentration have minimal effects on intracerebral pH and cerebral blood flow, perhaps due to blood-brain barrier mechanisms. To test this hypothesis, the consequences of an acute rise in the plasma bicarbonate concentration were studied in anesthetized rats previously subjected to an acute pressure pulse in the carotid system with unilateral damage to the blood-brain barrier. In rats subjected to a "heavy" hypertensive insult, the hemisphere on the side of the lesion showed a lactic acidosis, edema, and a depression of cerebral blood flow. An increase in the plasma bicarbonate concentrations of 15--20 mEq/1 during 35 minutes provoked a marked rise in the total CO2 content of this hemisphere, and a further increase in the lactate concentration, but did not later the brain edema nor affect further the already very low cerebral blood flow. An increase in the lactate concentration and a decrease of cerebral blood flow in the "reference" hemisphere indicated that the lesion was not completely unilateral. In rats subjected to a "moderate" hypertensive insult the changes were less pronounced and statistically not significant for all the parameters. There results illustrate the importance of an intact blood-brain barrier for the maintenance of intracerebral pH in the face of acute alterations in plasma [HCO3]. The impaired cerebral blood flow after an acute hypertensive insult did not appear to be influenced by the intracerebral [HCO3].
Intracerebral hemorrhage following carotid endarterectomy: a hypertensive complication?
Authors: Caplan L R , Skillman J , Ojemann R , Fields W S
Published: June 2011

Two patients with transient ischemic attacks and subsequent minor cerebral infarction had repair of very tight carotid stenosis, 4 and 5 weeks respectively after their stroke. Each developed intracerebral hemorrhage when hypertension was uncontrolled during the post-operative period. Hypertension is a significant complication of carotid endarterectomy, and may be a prominent factor in the development of intracerebral hemorrhage post-carotid endarterectomy.
Imaging the carotid bifurcation using continuous-wave Doppler-shift ultrasound and spectral analysis.
Authors: Lewis R R , Beasley M G , Hyams D E , Gosling R G
Published: June 2011

A non-invasive method is described for visualizing the carotid bifurcation using a continuous-wave Doppler-shift technique simultaneously with spectral analysis of the blood velocities from all parts of the vessel lumen. The system is directional so that arteries can be visualized in the presence of signals from adjacent veins. The technique uses a transducer which is attached to a position-sensing arm so that the position of the ultrasound beam on the neck, when sensing arterial blood flow-velocities, can be translated onto a storage oscilloscope. By repeated passes of the transducer across the vessel lumen a 2 dimensional image of the carotid bifurcation is formed. As each image point is marked, the full spectrum of blood-velocities corresponding to that position is continuously displayed on a second oscilloscope beside the image scope. Ultrasound images are compared with arteriograms and both continuous-wave and pulsed Doppler ultrasound imaging systems are discussed.
Cluster headache, hemicrania, and other head pains: morbidity of carotid endarterectomy.
Authors: Messert B , Black J A
Published: June 2011

Carotid endarterectomy has become a widely used approach to the treatment of cerebrovascular disease. In spite of increasing experience, a significant and varied morbidity remains attached to the procedure. A poorly recognized complication is postoperative headache. In a series of 57 endarterectomies in 50 patients, 24 patients experienced postoperative headaches encompassing the entire spectrum of vascular headaches: nonspecific diffuse headaches, severe hemicranias, cluster headaches occurring early and delayed, chronic paroxysmal hemicranias, carotidynia, and Eagle's syndrome. Five patients had hemicranias, and all were homolateral to the endarterectomy. Therefore, we hypothesize that the spontaneously occurring hemicranias, the counterparts of postsurgical headache syndromes, also may be due to some overt or occult injury or disease of the carotid vessels or carotid sheaths in the regions from the carotid bifurcation to the base of the skull.