bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of local cerebral blood flow determined by thermal and hydrogen clearance.
Authors: Gaines C , Carter L P , Crowell R M
Published: June 2011

Local cerebral blood flow (1CBF) was measured simultaneously in ten cats with (1) a large surface thermal diffusion probe resting on the cortex and (2) hydrogen clearance curves from implanted electrodes surrounding the thermal probe. A close correlation was found between 1CBF values obtained by the two methods. Since hydrogen clearance is accepted as quantitative, the data suggest that the thermal diffusion technique is a reliably quantitative means of measuring local cerebral blood flow.
Human pial vascular reactions to intravenous Nimodipine-infusion during EC-IC bypass surgery.
Authors: Auer L M , Oberbauer R W , Schalk H V
Published: June 2011

In previous experimental work, the Ca-antagonist Nimodipine had shown a predominantly cerebroarterial dilatory effect. In the present double-blind study of 16 patients, pial arterial and venous reaction was investigated during EC-IC bypass surgery, infusing 1 microgram kg-1min-1 of Nimodipine intravenously. In pial arteries with resting diameters between 25 and 70 micrometers, a significant 18% dilatation was observed. Results are considered promising for future trials in the treatment and prevention of cerebral ischemia caused by vasoconstriction or vasospasm, especially vasospasm following subarachnoid hemorrhage.
The angiopathy of subarachnoid hemorrhage: angiographic and morphologic correlates.
Authors: Smith R R , Clower B R , Peeler D F , Yoshioka J
Published: June 2011

In patients with subarachnoid hemorrhage, particularly hemorrhage due to aneurysmal rupture, there was a positive significant relation between angiographic vessel constriction and vessel pathology (angiopathy). Furthermore, there was a positive relationship between post-hemorrhage survival time and the severity of angiopathy. Factors such as age, sex, operations, steroid and CSF pressure seemed to have little affect on angiopathy following hemorrhage. Pathological changes were primarily limited to the involved major cerebral vessels themselves, with their branches rarely being affected. While intramural vascular hemorrhage was a common pathological feature in vessels showing severe pathology, the mere presence of blood surrounding an artery seemed to have little influence on vessel alterations.
The chronic influence of sympathetic nerves on cerebral vessels is age-related.
Authors: Mueller S M , Ertel P J , Felten D L , Overhage J M
Published: June 2011

The purpose of this study was to determine the effect of chronic sympathetic denervation on cerebral vessels of the spontaneously hypertensive rat when superior cervical ganglionectomy was performed in adulthood. In a previous study, we have demonstrated increased protein transfer across the cerebral vessels of the chronically denervated hemisphere when superior cervical ganglionectomy was performed in adolescent spontaneously hypertensive rats. After four weeks of sympathetic denervation, the adult rats in this study did not demonstrate increased protein transfer in the denervated compared to the innervated cerebral hemisphere. Thus, the "trophic" effect of sympathetic nerves on cerebral vessels appears to be age-related.
Increase of low serum concentrations of high-density lipoprotein (HDL) cholesterol in TIA-patients treated with phenytoin.
Authors: Kaste M , Muuronen A , Nikkilä E A , Neuvonen P J
Published: June 2011

Serum high density lipoprotein (HDL) cholesterol and other lipoproteins were measured in 27 TIA-patients with a mean age of 49 +/- 10 years before and during phenytoin therapy. The pretreatment concentrations of HDL-cholesterol (mmol/l, mean +/- SD) were lower (p less than 0.001) in male (1.03 +/- 0.25) and in female patients (1.15 +/- 0.44) than in healthy male (1.28 +/- 0.34) and female controls (1.52 +/- 0.31) respectively. After one month's phenytoin therapy HDL cholesterol concentrations reached normal levels (men 1.33 +/- 0.38, women 1.61 +/- 0.27) and after 9 months of therapy even surpassed them (men 1.47 +/- 0.27, p less than 0.05; women 1.91 +/- 0.33, p less than 0.01). Percent increase of HDL cholesterol after 9 months of therapy was 42 +/- 25 in men and 68 +/- 46 in women. There was a positive correlation (r = 0.43, p less than 0.05) between serum phenytoin level and increase of HDL cholesterol. HDL/LDL cholesterol ratio increased (p less than 0.01) also during 9 months of therapy (men from 0.26 +/- 0.05 to 0.36 +/- 0.10, women from 0.26 +/- 0.07 to 0.43 +/- 0.13) and showed a positive correlation (r = 0.91, p less than 0.001) with increase of serum HDL cholesterol. The HDL cholesterol levels achieved have been maintained with a mean serum phenytoin level of 5.6 +/- 3.6 mg/l. Phenytoin induced increase in serum HDL levels should not yet be equated with protection against atherosclerosis.
Cerebral embolism in the Michael Reese Stroke Registry.
Authors: Caplan L R , Hier D B , D'Cruz I
Published: June 2011

Infarction secondary to cerebral embolism was diagnosed in 127 (23.5%) of 540 patients in the Michael Reese Stroke Registry. Coronary artery disease, atrial fibrillation, valvular heart disease, mitral annulus calcification, and cardiomyopathy were the commonest etiologies. Echocardiography documented a potential embolic source in 7 patients without previously known heart disease, and clarified the cardiac pathology in many of the patients with known heart disease. The left anterior circulation was affected in 48%, right anterior in 37%, and posterior circulation in 15% of patients. CT was abnormal in 71% of the patients, and was approximately equally helpful in all locations. Nineteen percent of emboli presented with a deficit that was other than maximal at onset. Concurrent systemic embolism was unusual (2.3%). Prognosis was somewhat worse than in thrombotic stroke. Grouping of patients according to embolic source (intra-arterial, cardiac, and uncertain source) showed no differences in activity at onset, early course, or in subsequent course of the illness.
Risk of recurrent stroke in patients with atrial fibrillation and non-valvular heart disease.
Authors: Sage J I , Van Uitert R L
Published: June 2011

One-hundred-forty patients with atrial fibrillation (AF) due to non-rheumatic, non-valvular heart disease (NVHD) who suffered a cerebral infarct were identified. Fifty-three (38%) died of the initial stroke. The surviving patients were followed up to 9 years without anticoagulant therapy. In the 59 patients available for follow-up, the risk of recurrent cerebral ischemia remained at approximately 20% per year throughout the 9 year observation period. The recurrence rate was the same regardless of age, sex, previous myocardial infarction, or whether chronic AF or intermittent AF were present. Only 7 (12%) died from a second stroke, however. The high annual rate of recurrence and lack of controlled therapeutic trials in this population of patients warrant a prospective study to define the benefits and relative risks of anticoagulant therapy in AF due to NVHD.
Increased transendothelial channel transport of cerebral capillary endothelium in stroke-prone SHR.
Authors: Tagami M , Kubota A , Sunaga T , Fujino H , Maezawa H , Kihara M , Nara Y , Yamori Y
Published: June 2011

Permeability of brain capillaries of stroke-prone spontaneously hypertensive rats (SHRSP) was studied using labelling (horseradish peroxidase) and cytochemical techniques at the cellular level. In the cerebral capillary endothelium the tracer molecules were quickly transported by abundant transendothelial channels which directly connected the capillary lumen to the subendothelial space. Transendothelial channels are abundant and should be postulated as structural formations engaged in the increased transport of proteins across the capillary endothelium. Ultracytochemical studies revealed that the channels, bounded by indistinct delimiting membranes, initially had no acid phosphatase activity. With the passage of time, however, the channels showed acid phosphatase activity and were lined with distinct membranes. These observations suggested that the lysosomes might fuse with the transendothelial channels and might play an important part in the transport of macromolecules.
Comparison of the effects of hypertonic glycerol and urea on brain edema, energy metabolism and blood flow following cerebral microembolism in the rat. Deleterious effect of glycerol treatment.
Authors: Bralet J , Beley P , Bralet A M , Beley A
Published: June 2011

Cerebral microembolism was performed in rats by injecting radioactive calibrated 50 mu microspheres into the left internal carotid artery. The use of radioactive microspheres as embolic agents enabled the number of microspheres to be determined in each cerebral hemisphere. Edema was assessed 24 h after embolization by measuring brain water, sodium, and potassium content. Equiosmolal doses (40 mmol/kg) of glycerol or urea were injected i.p. at various times before sacrifice. Both treatments caused similar changes in water and electrolyte content, brain dehydration being maximal 30 min after urea and 2 h after glycerol injection. Cerebral energy metabolism and regional blood flow were evaluated at the times of maximal brain dehydration. Urea treatment resulted in an improvement of the cerebral circulation whereas glycerol treatment led to a deterioration of cerebral blood flow which cannot be explained by failure to reduce edema and the consequent microcirculatory impairment. Urea treatment had no marked effect on cerebral energy metabolism whereas glycerol injection resulted in an important increase in brain lactate level which may be relevant to the impairment of cerebral reperfusion. These results point out that administration of a metabolized solute like glycerol may exert deleterious effects on the ischemic brain.
Spinal cord vasculature of the rat: a histochemical study of the metabolism of arteries and arterioles.
Authors: Cannon M S , Gelderd J B
Published: June 2011

Spinal cord arteries and arterioles of adult female rats were examined histochemically to determine their metabolic profiles. The metabolic pathways evaluated included those related to aerobic (oxidative phosphorylation, Kreb's cycle and respiratory chain) and anaerobic (glycolysis) capacity, hexosemonophosphate-shunt activity, beta-oxidation of fat and adenosine triphosphate utilization. The amounts of deoxyribonucleic and ribonucleic acids were determined as an indication of protein synthesis. The present findings indicate that arteries of the rat spinal cord are metabolically active with high capacities for both aerobic and anaerobic metabolism, and possess a significant potential for nucleic acid and protein synthesis. Lipid catabolism, via beta-oxidation of fat, may serve as one source of energy. The arteries also demonstrate a high capacity for utilization of adenosine triphosphate. In contrast, the spinal cord arterioles show a lower capacity for aerobic metabolism and lipid utilization, while anaerobic glycolysis may be a main source of energy. The arterioles also demonstrate a significant potential for nucleic acid and protein synthesis, in addition to a high capacity for adenosine triphosphate utilization.
Cerebral fat embolism following cardiac surgery.
Authors: Ghatak N R , Sinnenberg R J , deBlois G G
Published: June 2011

We describe 3 cases of cerebral fat embolism associated with cardiac surgery. The autopsy findings suggested that in 2 cases, the embolic fat globules entered the systemic circulation directly as a result of protrusion of epicardial fat into the left atrial chamber along the suture line in one case, and through an atrial septal defect in the other. The characteristic latent interval between surgical trauma and onset of neurologic manifestations was lacking in both cases. The evolution of neurologic manifestations and the pathologic findings in the third case were similar to those usually seen in posttraumatic fat embolism. This study suggests that the pathogenetic mechanisms of cerebral fat embolism following cardiac surgery may vary in different cases. Also, it emphasizes the importance of autopsy in the investigation of this serious but preventable complication.
Continuous measurement of regional cerebral blood flow using krypton-81m.
Authors: Ogawa A , Sakurai Y , Suzuki J
Published: June 2011

We have developed a new method for taking continuous measurements of rCBF by means of continuous infusion of 81mKr. Using this method, it is possible to follow the sequential changes in blood flow of various brain regions continuously. The method makes it possible to observe the sequential changes in CBF following drug administration, motor activation and various kinds of stimulation, and, furthermore, to observe the CO2 reactivity and autoregulation of cerebral vessels. It will undoubtedly prove useful in the investigation of various pathological states.
Hemiplegics after a first stroke: late survival and risk factors.
Authors: Solzi P , Ring H , Najenson T , Luz Y
Published: June 2011

Scanning 3000 cases admitted for rehabilitation after cerebrovascular accident over a 20 year period produced a sample of 1369 subjects, without age restrictions, admitted within six months of a first stroke of thrombotic etiology. In this sample, survival rates showed no significant difference between men and women. Age at onset, however, clearly influenced survival changes; the expected mean survival was 6 years at 40 and 2 at age 80; average loss of life was 14 years for the whole sample, meaning a vital prognosis two to three times worse than that of the general population. At least 86% of the sample presented one or more of five etiological antecedents to stroke: hypertensive heart disease, peripheral vascular disease, diabetes mellitus, myocardial infarction and atrial fibrillation. In 87% of those, HHD and/or PVD were present. Presence of hypertension significantly lowered life expectancy and so did PVD; their influence is felt from the earliest stages. In contrast, diabetes mellitus, the next most common factor, has a late influence, starting about the fifth year after stroke. MI and AF were present in relatively fewer patients, but they contributed towards a considerable decrease in life expectancy, evident from the first stages, the more drastic reduction being observed in the AF group.
Interrelationships among wall structure, smooth muscle orientation, and contraction in human major cerebral arteries.
Authors: Walmsley J G , Campling M R , Chertkow H M
Published: June 2011

Human major cerebral arteries were fixed under pressure in the brain or after excision and ligation. They were sectioned and stained for light microscopy. Sterological point counting was used on mid-plane longitudinal sections of ten segments to determine that the media occupied 52.0% +/- 6.39 (SD) of the arterial wall and that the smooth muscle comprised 72.0% +/- 4.76 (SD) of the media. In arterial segments containing nine planar bifurcations, areas of varying muscle orientation and composition were identified and mapped out. A circumferential alignment of smooth muscle was consistently found in the cerebral branching systems except for the bifurcation region proximal to the apex at major bifurcations where the regular pattern was replaced by multilayered multidirectional smooth muscle. Theoretical models relating smooth muscle contraction to arterial caliber in cylindrical segments are outlined. In the extreme case of complete closure of an artery, our prediction is that for a typical cerebral arterial media the outermost muscle cells should have to contract to 42% of their relaxed length. The possible importance of medial smooth muscle patterns in the pathogenesis of cerebrovascular lesions is discussed.
Angiographic findings in a young man with recurrent stroke and positive fluorescent treponemal antibody (FTA).
Authors: Aldrich M S , Burke J M , Gulati S M
Published: June 2011

A young man with a history of two strokes was found to have serologic evidence of a prior syphilitic infection, abnormal spinal fluid, and angiographic evidence of diffuse intracranial and extracranial angiopathy which we believe was due to tertiary syphilis, although his use of oral amphetamines cannot be ruled out as a contributing factor. This is the first reported case in which angiography has demonstrated both intracranial and extracranial disease arterial disease due to neurosyphilis. Since syphilis can produce diffuse cerebral arterial changes, this diagnosis should be considered in young patients with stroke even when non-treponemal serologic tests are negative.
Internal carotid occlusion: a prospective study.
Authors: Cote R , Barnett H J , Taylor D W
Published: June 2011

Forty-seven patients with ICA occlusion and who presented either without any or only a mild neurological deficit were prospectively followed for an average of 34.4 months. During this period of time, 11 patients (23.5%) suffered a cerebral infarction of which two-thirds were ipsilateral to the occluded artery. The stroke rate distal to an occluded ICA artery was 5% per year. Twenty-four patients (51%) continued to experience TIA's in the territory of the occluded artery. The mortality rate was low (8.5%) during follow-up. Whether extracranial-intracranial bypass surgery will decrease the risk of cerebral infarction in this subgroup of patients is unknown. The International EC/IC Collaborative Trial may elucidate this point because this subgroup represents one of the randomization strata of that study.
Local vascular response to change in carbon dioxide tension. Long term observation in the cat's brain by means of the hydrogen clearance technique.
Authors: von Kummer R
Published: June 2011

Thirty six small hydrogen sensitive electrodes were inserted into the brains of 6 cats to evaluate the local vascular response to change in PaCO2, of cortex, subcortical white matter, and caudate nucleus. Repeated measurements (617) of local cerebral blood flow (ICBF) were performed over a period of 12 weeks. Within a PaCO2 range from 19 to 96 mmHg the local response of CBF was linear in most of the regions measured. The absolute local CO2 reactivity (CO2-R) showed a positive correlation to ICBF at PaCO2 = 40 mmHg (ICBF40) with the regression line: absolute CO2-R = 0.02 ICBF40 + 0.22, r = 0.71 (p less than 0.01). Therefore relative ICBF change was calculated in relation to ICBF40 to make comparisons between the CO2 response of different measuring days and of different regions examined. No significant change in relative CO2-R was observed during the 12 weeks interval. Differences of relative CO2-R between investigated regions were insignificant. The uniformity of relative CO2 response might support the hypothesis of a direct effect of PaCO2 or pH on the vessel wall. For comparison of CBF, the individual determination of CBF40 and relative CO2-R would be necessary.
Observations of the dynamics of ionic potassium-38 in brain.
Authors: Duncan C C , Lambrecht R M , Bennett G W , Rescigno A , Ment L R
Published: June 2011

Short time course potassium dynamics in brain were investigated in the cat. 38K (T1/2 = 7.6m) was prepared on the BNL 60" cyclotron by the 40Ar(p, 3n)38K reaction. Positron decay in brain was measured by the limited angle of view positron camera (LAPC). Radioactivity corrected for physical decay following intravenous bolus injection of 38K showed an initial peak followed by a washout phase with a subsequent monotonic increase. The slope of the washout phase was linearly related to PaCO2 and the subsequent monotonic increase paralleled the arterial concentration of the tracer. No significant changes in 38K radioactivity were determined following coma producing levels of phenobarbital or seizure producing doses of potassium penicillin as compared to control.
Risk factors related to ischemic and hemorrhagic cerebrovascular disease at autopsy: the Honolulu Heart Study.
Authors: Stemmermann G N , Hayashi T , Resch J A , Chung C S , Reed D M , Rhoads G G
Published: June 2011

This study of cerebrovascular lesions at autopsy among Hawaiian Japanese men identifies similar risks factors for cerebral infarction and hemorrhage that have been identified in a previous incidence study. Demonstrated differences were essentially the same whether subjects with these tissue changes were compared to men showing no central nervous system disease at autopsy or when they were compared with men still alive. Cerebral infarcts accompanied myocardial infarction (CHD) in 58% of autopsy cases and were associated with CHD risk factors (high serum cholesterol, hypertension, severe atherosclerosis of the coronary arteries and aorta). These associations did not persist when CHD cases were removed from the analysis, indicating there were two subsets of men with cerebral infarction. Hypertension was strongly associated with hemorrhagic disease, as were cigarette use and alcohol consumption.
Naloxone administration to patients with acute stroke.
Authors: Jabaily J , Davis J N
Published: June 2011

Naloxone, an opiate antagonist, has recently been reported to temporarily reverse neurologic deficits associated with subarachnoid hemorrhage. To determine if this unexpected effect of naloxone might also occur in other forms of cerebrovascular diseases, 13 patients who presented with acute neurologic deficits were administered intravenous naloxone. In 3 of these patients, coincidental improvement in neurologic status was seen. In one patient the improvement was permanent. Ten of the 11 patients with non fatal neurologic damage improved later in their hospital course--7 of them to their pre-admission state. The only side effect noted was the temporally related onset of a single focal seizure in an ethanol intoxicated patient with an intracerebral hemorrhage.
Comparative studies of regional CNS blood flow and evoked potentials in the cat. Effects of hypotensive ischemia on somatosensory evoked potentials in cerebral cortex and spinal cord.
Authors: Sato M , Pawlik G , Umbach C , Heiss W D
Published: June 2011

Functional resistance to graded hypotensive ischemia of various segments of the somatosensory pathway was determined in anesthetized cats by repeated concurrent recordings of regional blood flow measured by hydrogen clearance, and evoked potentials (EPs), of dorsal horn of lumbar spinal cord and cerebral cortex. During normal resting CNS blood flow (CBF), there were significant successive reductions of EP amplitudes, recorded from presynaptic spinal components (634, 424-949 microV; re-linearized mean and 95% confidence limits of log-transformed data) compared to postsynaptic spinal (359, 247-522 microV) and presynaptic cortical (50, 32-79 microV) and to postsynaptic cortical components (33, 22-50 microV). During ischemia amplitudes of EPs in spinal cord and cerebral cortex showed significantly different behaviors. The presynaptic spinal component was virtually independent of regional blood flow down to 12 percent of resting values, the postsynaptic cortical component exhibited strongest positive correlations (r = 0.45) with flow. In both regions postsynaptic amplitude was more sensitive to flow changes than respective presynaptic amplitudes. Despite similar regression coefficients for intermediate segments of somatosensory pathway, only postsynaptic spinal components were significantly correlated (r = 0.40) with regional flow. Presynaptic cortical amplitudes were variable and no significant flow dependence was demonstrated. Results suggested that in comparable degrees of regional ischemia of CNS functional integrity is determined by numbers of synaptic transmissions involved locally. Comparatively simple structures, e.g. the spinal cord, are less susceptible to ischemia and complex neuronal networks, e.g. the cerebral cortex, are more susceptible.
Predictors of stroke-associated mortality in the elderly.
Authors: Khaw K T , Barrett-Connor E , Suarez L , Criqui M H
Published: June 2011

Although stroke is a major cause of death in older adults, few studies have examined the independent contribution of cardiovascular disease risk factors to stroke mortality in the geriatric age group. We report here a nine-year followup of a Southern California community of 2107 men and women aged 65 to 84 years. In this older cohort, age was the most significant independent risk factor for stroke-associated mortality in both sexes. Systolic blood pressure was weakly but significantly associated with stroke mortality in this older age group. Cigarette smoking was positively related and educational level of head of household negatively related to stroke mortality in both sexes, with the predominant effect in women. No significant independent effect of cholesterol, fasting plasma glucose or obesity was discernible. Both blood pressure and cigarette smoking are potentially remedial risk factors for stroke after age 65.
Effects of calcium channel blockers on pial vascular responses to receptor mediated constrictors.
Authors: Rosenblum W I
Published: June 2011

Published studies have seldom examined the in vivo effect of calcium channel blockers on the contractile response of cerebral vessels to receptor mediated constrictors, and have had little success in demonstrating any effect of a single systemic dose of the channel blockers in contrast to the effects of continuous infusions. The present study examines the effect of topical norepinephrine, prostaglandin F2 alpha and serotonin on pial arterioles of the mouse, in the presence of locally applied channel blockers and also 15 and 30 minutes after a single i.p. injection of the blockers. Verapamil, nisoldipine and nimodipine were all effective inhibitors of constriction by either route of administration, and in doses having little or no dilating action. The data not only indicate that single systemic doses can effectively alter contractile behavior of cerebral arterioles, but also demonstrate the importance of testing these drugs against receptor mediated constrictors whose effects, alone or in combination, may be important during initiation or maintenance of cerebral vasospasm.
The angiopathy of subarachnoid hemorrhage I. Role of vessel wall catecholamines.
Authors: Yoshioka J , Clower B R , Smith R R
Published: June 2011

Subarachnoid hemorrhage (SAH) due to rupture of the right middle cerebral artery (RMCA) produced specific anatomical and biophysiological responses in the involved feline vessels. The RMCA showed morphological alterations that became progressively more severe with time and were widespread within the cerebral vascular tree. SAH also resulted in an acute depletion of vessel catecholamine levels which remained depressed over a 30 day period. When the cerebral vessels of cats were severely depleted of catecholamines (using reserpine) prior to induced SAH, morphological alterations were significantly reduced both in severity and in degree of spread within the cerebral vascular network. The results of this study suggest that the concentration of norepinephrine within the vessel at the time of hemorrhage plays a significant role in the production of the angiopathy that follows SAH.
Vertebrobasilar ischemia after total repair of tetralogy of Fallot: significance of subclavian steal created by Blalock-Taussig anastomosis. Vertebrobasilar ischemia after correction of tetralogy of Fallot.
Authors: Kurlan R , Krall R L , Deweese J A
Published: June 2011

Patients who have undergone a Blalock-Taussig anastomosis for treatment of congenital heart disease may have the vascular anatomy of the subclavian steal syndrome. Cerebral ischemia has been reported in such patients, but not when total surgical correction has eliminated other predisposing factors. We report a patient who developed vertebrobasilar insufficiency 31 years after Blalock-Taussig anastomosis and 4 years after total intracardiac repair of tetralogy of Fallot. He had angiographically proven subclavian steal and no other known predisposing factor for cerebral ischemia. This case suggests that symptomatic subclavian steal may be a late risk of surgical treatment of congenital heart disease that leaves the vascular anatomy of subclavian steal intact. Vascular reconstructive surgery can be effective treatment for these patients and may be indicated prophylactically at the time of intracardiac repair if subclavian steal syndrome becomes a more frequently recognized sequela of prior Blalock-Taussig anastomosis.
Indirect assessment of carotid occlusive disease by ocular pneumoplethysmography. 500 mm Hg vacuum pressure measurements and ocular pulse timing.
Authors: Schwartz J A , Flanigan P , Schuler J J , Ryan T J , Castronuovo J J
Published: June 2011

The interpretation and diagnostic value of the ophthalmic artery pressure measurement and ocular pulse timing modes of the 500 mm Hg vacuum OPG-Gee ocular pneumoplethysmograph were evaluated in 65 patients who underwent aortic arch and cerebral arteriography. Data analysis revealed the OPG-Gee differential tracing which electronically compares and amplifies differences between the right and left eye pulse waveforms to be of little value. In predicting the presence of a greater than or equal to 50 percent diameter unilateral stenosis, an eye-eye pulse interval of greater than 15 msec was 82 percent accurate, a greater than or equal to 5 mm Hg ophthalmic artery pressure difference was 77 percent accurate and when combined these two criteria were 84 percent accurate. Neither of the criteria intended to detect bilateral carotid lesions, eye-ear pulse interval nor ophthalmic/brachial pressure index, were reliable. Ocular pulse timing was found to be highly specific but insensitive to hemodynamically significant carotid disease. OPG-Gee pressure determinations were more sensitive but lacked specificity. In combination, these criteria allowed identification of unilateral hemodynamically significant lesions with a sensitivity of 83 percent and a specificity of 86 percent. If used to detect more severe degrees of arteriographic stenosis, 60 and 70 percent diameter reduction, the overall diagnostic accuracy of these techniques was not improved. These results do not justify the use of the OPG-Gee instrument as a single noninvasive test for carotid arterial disease.
Effect of lidoflazine on cerebral blood flow following twelve minutes total cerebral ischemia.
Authors: Dean J M , Hoehner P J , Rogers M C , Traystman R J
Published: June 2011

Lidoflazine, a calcium channel blocker, was administered to dogs following twelve minutes of cerebral ischemia, induced by aortic cross-clamping. The effects of lidoflazine (1 mg/kg i.v.) on cerebral blood flow following ischemia was studied in 15 anesthetized, mechanically ventilated dogs. Cerebral blood flow was measured with the radiolabelled microsphere technique before and 10, 30, 60, 90 and 150 minutes following ischemia. Cerebral blood flow increased in all brain regions following ischemia, but by 60 minutes had decreased to control values. Lidoflazine had no effect on this reperfusion phenomenon, or on the distribution of blood flow within the brain. Regional cerebral blood flow was also not altered by lidoflazine therapy. Our data demonstrate that this dose of lidoflazine has no effect on regional or total cerebral blood flow following 12 minutes of cerebral ischemia in dogs. These data do not support perfusion preservation as a mechanism of amelioration of neurologic injury after ischemia by this calcium channel blocker.
Naloxone ameliorates the pathophysiologic changes which lead to and attend an acute stroke in stroke-prone/SHR.
Authors: Wexler B C
Published: June 2011

Stroke-prone, spontaneously hypertensive rats (SP/SHR) were fed a low protein (8%) fish diet + 1% saline at the time of weaning; some were treated with Naloxone (0.4 mg/100 gms bw/sc/2 X daily/5 days per week). Naloxone-treated animals did not develop high blood pressure or strokes. Sixty-two days after feeding the low protein fish diet, blood pressure levels reached 260-300 mmHg and all of the non-treated animals exhibited acute and severe strokes; Naloxone treatment was again initiated for half of the SP/SHR. By Day 4 (post stroke), all of the non-treated SP/SHR were dead; Naloxone-treated SP/SHR survived until Day 12 (post stroke). Naloxone-treatment during the post-stroke period caused significant reduction of blood pressure, ACTH, and beta-endorphin levels concomitant with reduced cerebral edema and clearance of hepatic lipid infiltration. It is suggested that anti-opiate treatment may ameliorate the severe hypertension-inducing effects of a low protein fish diet and thereby prevent the appearance of strokes in SP/SHR as well as palliate the cerebral edema and fatty liver which characteristically appear in the immediate post-stroke period in fish-fed SP/SHR. The central mechanism of this palliative effect may be through reduced hypothalamic-pituitary-adrenal activity.
Cerebrovascular diseases in a fixed population of Hiroshima and Nagasaki, with special reference to relationship between type and risk factors.
Authors: Lin C H , Shimizu Y , Kato H , Robertson T L , Furonaka H , Kodama K , Fukunaga Y
Published: June 2011

A study was made of the incidence of cerebrovascular disease, the chronological trends, and the relationship between the disease types and risk factors in 16,491 citizens of Hiroshima and Nagasaki. The subjects underwent medical examination at least once between 1958-74, and were free of cerebrovascular disease at the initial examination. During the 16-year period, 1.162 cases of cerebrovascular disease developed in the study population, with diagnosis definite in 621. By type, there were 108 cases of cerebral hemorrhage, 469 cases of cerebral infarction, 33 cases of subarachnoid hemorrhage, and 11 cases of other unclassifiable types. As a risk factor of cerebral hemorrhage, elevation of systolic and diastolic blood pressure was the most closely related to onset, and left ventricular hypertrophy on electrocardiogram (ECG), and proteinuria were also related. However, a tendency was seen for the risk to be higher when the levels of serum cholesterol were lower. In cerebral infarction, aging like systolic blood pressure, was a most important risk factor. Left ventricular hypertrophy on ECG, proteinuria, and diabetes could also be risk factors. However, the relation to blood pressure, especially diastolic blood pressure, was not so great as in the case of cerebral hemorrhage.
Clinical-CT correlations in TIA, RIND, and strokes with minimum residuum.
Authors: Calandre L , Gomara S , Bermejo F , Millan J M , del Pozo G
Published: June 2011

An approach to the controversy of the physiopathology and classification of ischemic stroke is attempted in this study. The computed tomographies (CT) of 88 patients with transient ischemic attacks (TIA), 46 with reversible ischemic neurologic deficits (RIND) and 70 with ischemic strokes with minimum residuum (SMR) are analysed. The incidence of focal ischemic lesions on CT is 25% in TIA and RIND and 35% in SMR, when the study was performed after the first 24 hours. The incidence of cerebral infarction was much lower when the CT was performed within the first 24 hours after the clinical event. No significant differences in size or location of the infarction were found between the different groups. Deep infarctions were smaller than superficial ones. TIA duration correlated neither with the incidence of CT abnormalities nor with the size of the lesions. No correlation was found between doppler or oculoplethysmography abnormalities, clinical groups and CT findings. In reference to the structural lesions that underlie the clinical syndromes, TIA, RIND and SMR should not be considered as different groups.
Prostaglandin release from isolated rabbit cerebral cortex micro-vessels--comparison of 6-keto PGF1 alpha and PGE2 release from micro-vessels incubated in 100% O2, room air and 95% N2:5% CO2.
Authors: Rodrigues A M , Gerritsen M E
Published: June 2011

Prostaglandin release from microvessels isolated from the rabbit cerebral cortex was determined under three different atmospheric conditions: 100% O2 ("O2") room air, and 95% N2:5% CO2 ("N2-CO2"). Initial studies with homogenates prepared from rabbit cerebral microvessels (RCMV) indicated two pathways of enzymatic PGH2 transformation, namely PGI2 synthase and GSH-dependent PGH-PGE isomerase. We measured the release of the principal products of these pathways, 6-keto PGF1 alpha and PGE2 from freshly prepared RCMV. The release of 6-keto PGF1 alpha exceeded that of PGE2 in all three protocols. RCMV incubated in "N2-CO2" exhibited a reduction in the release of 6-keto PGF1 alpha compared to room air or "O2" incubated RCMV, evident at 30-60 min of incubation. No significant differences in the release of PGE2 were observed among the three incubation protocols. In all three incubation protocols the ratio of 6-keto PGF1 alpha to PGE2 did not differ during the initial 10 minutes of each incubation. After 30 to 60 min of incubation, this ratio did not change from the "O2" or room air treated RCMV, but decreased significantly for the "N2-CO2" treated group. To determine the reversibility of the apparent "N2-CO2" induced decline in 6-keto PGF1 alpha release, microvessels were removed from the nitrogen atmosphere and incubated in room air. Release was measured during the initial 10 min following reintroduction to room air and was compared to room air pretreated controls treated in an identical manner.(ABSTRACT TRUNCATED AT 250 WORDS)
Epidemiology of acute cerebrovascular disease before the age of 55 in the Stockholm County 1973-77: I. Incidence and mortality rates.
Authors: Mettinger K L , Söderström C E , Allander E
Published: June 2011

The incidence and mortality rates of cerebrovascular disease (CVD) before age 55 were estimated for the Stockholm county between 1973 and 1977 using community based diagnosis and death statistics registers. Annual validation procedures concluded that less than 5% of hospitalized patients may have escaped registration. During the study period a diagnosis of CVD (initial stroke or TIA) was reported in 2,103 individuals, giving annual average crude incidence rates for stroke and TIA of 34 and 4 respectively per 100,000 inhabitants under age 55. Hemorrhagic lesions were reported in 45.4% of the cases, ischemic lesions in 33.1% and unclassified lesions in 21.5%. For all diagnostic categories a strong correlation to age is found, and for most categories the male:female ratio is high. The mortality rates are high for hemorrhagic lesions and low for ischemic and unclassified lesions. Incidence rates are higher than in Uppsala and Gothenburg, Sweden, but lower than in North Karelia, Finland. Mortality rates are similar to those reported by most other investigators.
Ischemic brain edema following occlusion of the middle cerebral artery in the rat. II: Alteration of the eicosanoid synthesis profile of brain microvessels.
Authors: Asano T , Gotoh O , Koide T , Takakura K
Published: June 2011

Using the rat middle cerebral artery occlusion model, alterations in the eicosanoid synthetic capacity of brain microvessels following ischemia were studied by radiochromatography. Brain microvessels of normal rats predominantly produced hydroxyacids with relatively small amounts of PGD2 and PGE2 from exogenous arachidonic acid. Confirmation that hydroxyacids and prostaglandins were products respectively of lipoxygenase(s) and cyclooxygenase was obtained by experiments using indomethacin and eicosatetraynoic acid. The eicosanoid synthetic capacity of the brain microvessel, especially of hydroxyacids, was significantly enhanced 24 and 72 hours after the onset of ischemia. Because this is the phase of maximum edema in the present model, enhanced eicosanoid production in the brain microvessel may be involved in the mechanisms that underly ischemic brain edema.
Hypertensive putaminal hemorrhage presenting with hemichorea.
Authors: Jones H R , Baker R A , Kott H S
Published: June 2011

A progressive motor deficit primarily manifested by hemichorea developed in a 42-year-old hypertensive man. CT scan demonstrated contralateral putaminal hemorrhage. The patient's course was benign. Previous cases of acute hemichorea familiar to use and documented by CT scans have involved nonhemorrhagic lesions of either the putamen or caudate.
Acute ethanol ingestion increases platelet reactivity: is there a relationship to stroke?
Authors: Hillbom M , Kangasaho M , Kaste M , Numminen H , Vapaatalo H
Published: June 2011

The effects of ethanol ingestion on ADP-induced platelet aggregation and associated thromboxane formation were studied in the platelet-rich plasma of 10 healthy male volunteers, each serving as his own control. Ethanol caused a transient decrease in threshold concentration of ADP to produce irreversible aggregation. Over a wide range of ADP total platelet aggregation was increased. In the presence of irreversible aggregation, formation of thromboxane B2 rose from 303 +/- 56 to 950 +/- 212 fmol per 10(7) platelets (p less than 0.01). The effects lasted as long as ethanol was present in blood, did not significantly correlate to blood ethanol levels and exhibited great individual variation. It remains to be proved, whether these observations could contribute to the increased risk of ischemic brain infarction associated with acute ethanol ingestion.
Nationwide co-operative study of intracranial aneurysm surgery in Japan.
Authors: Nishimoto A , Ueta K , Onbe H , Kitamura K , Omae T , Goto F , Ohneda G , Chigasaki H , Tsuru M , Suzuki J
Published: June 2011

A cooperative study was made of 4750 intracranial aneurysm cases collected from 133 neurosurgical clinics in Japan by letter inquiry for the period of 2 years from January 1974 to December 1975. Among them, 4124 cases (87%) had a single aneurysm, and 626 cases (13%) had multiple ones. Direct radical surgery was done in 78% of all cases, carotid ligation in 2% and non-surgical treatment in 17%. Direct surgery in a mortality rate of 15% for ruptured aneurysm cases and 7% for nonruptured cases. Radical surgery within 24 hours after rupture had a mortality of 51%, while those within 1 week and 2 weeks were 39% and 30% respectively; grade I or II patients, however, showed much better surgical results even in early operations. The neurosurgical clinics included in this study were spread throughout most of Japan. Micro-surgical technic was already in use of aneurysm surgery at the time of this study in Japan.
Sympathetic nerve activity: a link to stroke?
Authors: Mueller S M , Black W L
Published: June 2011

Spontaneously hypertensive rats (SHR) have been shown to have an increased capacity for superior cervical sympathetic nerve activity which may protect against stroke (Mueller et al: Stroke 13: 115, 1982). Sympathetic nerve activity has never been examined in the stroke-prone substrain of SHR (SP). In this study we measured superior cervical sympathetic nerve activity during rest and during a maximal sympathetic response in SHR, SP, and their normotensive controls, Wistar-Kyoto (WKY). The resting superior cervical sympathetic nerve activity of SP was significantly less than SHR (p less than 0.02) but not different from WKY. During central ischemia, used to induce maximal sympathetic response, the increase in SP sympathetic nerve activity was significantly less than SHR (p less than 0.001) but was not different from WKY. This diminished capacity for elevated superior cervical sympathetic nerve activity in stroke-prone SHR may relate to their increased predisposition to stroke because sympathetic hyperactivity cannot protect cerebral vessels during acute hypertension.
Cerebral infarction in rats using homologous blood emboli: development of a new experimental model.
Authors: Kaneko D , Nakamura N , Ogawa T
Published: June 2011

A reproducible model of thromboembolism in the rat was developed and the temporal relationship between hydrogen clearance, regional cerebral blood flow (rCBF) and power spectral-analyzed electroencephalographic (EEG) activity explored for up to four hours postinsult. Sixteen rats were subjected to right internal carotid artery homologous blood embolization after electrocautery of the pterygopalatine artery. Four rats were subjected to sham operation. Cerebral angiography before and for up to four hours postinsult was used to verify the distal migration and fragmentation of the emboli. Preembolic mean rCBF was 62 +/- 9 ml . 100g-1 . min-1 and 65 +/- 12 ml . 100g-1 . min-1 in the embolized and contralateral sides, respectively. Based upon the distribution of the emboli at sacrifice, the experimental group of 12 rats fell into three subgroups: unilateral proximal embolism, n = 8; unilateral peripheral embolism, n = 3; and bilateral proximal embolism, n = 1. In unilateral proximal embolism the mean rCBF in the embolized hemisphere ranged between 10 and 20 ml . 100g-1 . min-1 and correlated well with changes in EEG power spectra. In unilateral peripheral embolism, the mean rCBF in the embolized hemisphere fell significantly 30 min postembolism. It returned progressively towards preembolic values as the embolic clots migrated distally and fragmented. Despite the restoration of rCBF, recovery of EEG activity appeared to be delayed. Our results did not show luxury perfusion after embolic insults. The time course for the reopening of the embolized artery and the delay in recovery of neuronal function (i.e., EEG activity) relative to the restoration of rCBF are discussed.
The effect of a thromboxane synthetase inhibitor, OKY-046, on urinary excretion of immunoreactive thromboxane B2 and 6-keto-prostaglandin F1 alpha in patients with ischemic cerebrovascular disease.
Authors: Uyama O , Nagatsuka K , Nakabayashi S , Isaka Y , Yoneda S , Kimura K , Abe H
Published: June 2011

Thromboxane synthetase activity is selectively inhibited by (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid hydrochloride monohydrate (OKY-046). A single dose of 100 mg OKY-046 was orally administered to patients with ischemic cerebrovascular disease and healthy volunteers. Platelet aggregation and thromboxane B2 (TXB2) generation of intact and homogenised platelets induced by 1.0 mM sodium arachidonate were measured before and at 1, 4, 6 and 8 h after dosing. OKY-046 inhibited arachidonate-induced aggregation in platelet rich plasma from some, but not all, individuals, whereas platelet TXB2 generation was almost completely inhibited by a single dose of 100 mg OKY-046, in all of the patients and healthy volunteers. Endogenous TXA2 and prostacyclin (PGI2) biosynthesis were assessed by measurement of urinary immunoreactive TXB2 (i-TXB2) and 6-keto-PGF1 alpha (i-6-keto-PGF1 alpha) before and at 0-3, 3-6, 6-9 h after dosing. OKY-046 increased the urinary i-6-keto-PGF1 alpha coincidently with a decrease of urinary i-TXB2, both in patients and healthy volunteers. These effects of a selective thromboxane synthetase inhibitor will improve a disturbed balance between TXA2 and PGI2, associated with the development of ischemic cerebrovascular disease.
CT contrast enhancement on brain scans and blood-CSF barrier disturbances in cerebral ischemic infarction.
Authors: Hornig C R , Busse O , Buettner T , Dorndorf W , Agnoli A , Akengin Z
Published: June 2011

CT contrast enhancement of the ischemic infarction, blood-CSF barrier function for albumin, and severity of neurological symptoms were evaluated at predefined intervals in 41 patients with supratentorial ischemic infarctions. Contrast enhancement was most frequently observed in the 2nd and 3rd week after the stroke. This late CT enhancement was not related to infarction size and severity of blood-CSF barrier disturbance. The rare appearance of CT enhancement in the 1st week was usually associated with extensive infarctions and accompanied by blood-CSF barrier disturbances. These barrier disturbances, which occurred with higher frequency and greater severity in extensive infarctions (peak 3rd day), generally persisted for several weeks. We suggest that contrast enhancement in the 1st week after an ischemic stroke is due to diapedesis from necrotic capillaries; the more frequently observed late enhancement might be the result of a blood-brain barrier disturbance which in turn is hypothetically attributed to increased pinocytotic activity of regenerated endothelial cells.