bluuebunny/crossref_metadata_2025 huggingface dataset:
Area-at-risk determination by technetium-99m-hexakis-2-methoxyisobutyl isonitrile in experimental reperfused myocardial infarction.
Authors: De Coster P M , Wijns W , Cauwe F , Robert A , Beckers C , Melin J A
Published: June 2011

In a canine model of reperfused myocardial infarction, we tested the hypothesis that after reperfusion, technetium-99m-hexakis-2-methoxyisobutyl isonitrile (Tc-MIBI) tomographic imaging still reflects occlusion blood flow when the tracer is injected before reperfusion. Nine anesthetized dogs underwent 2 hours of coronary occlusion followed by 3 hours of reperfusion ending by being killed. Reference coronary blood flow was determined by radioactive microspheres injected during occlusion and after reperfusion. Biopsies in normal and ischemic myocardium and single photon emission computed tomography were obtained during occlusion and after reperfusion. Circumferential profiles were applied to axial slices divided into 5-degree sectors. The sectors were divided into 3 groups selected on the occlusion acquisition (normal, mildly reduced, and severely reduced) and compared with the postreperfusion acquisition. Tissular Tc-MIBI kinetics was assessed both by Tc-MIBI time-activity curves of normal and ischemic tissue obtained by biopsy and by the relative gradient between normal, ischemic, and necrotic postmortem tissue samples. In biopsy samples, Tc-MIBI content remained unchanged during occlusion and after reperfusion in normal as well as in ischemic tissue (4,662 +/- 2,237 counts/min/mg vs. 4,599 +/- 1,577 counts/min/mg in normal tissue, NS; 941 +/- 903 counts/min/mg vs. 1,087 +/- 721 counts/min/mg in ischemic tissue, NS). In postmortem tissue samples, there was a good correlation between occlusion microsphere blood flow and Tc-MIBI activity (r = 0.91). In the necrotic samples, mean normalized Tc-MIBI activity (10 +/- 17%) was slightly higher than the normalized microsphere blood flow (3 +/- 3%, p less than 0.001) but markedly lower than the normalized microsphere reperfusion blood flow (63 +/- 31%, p less than 0.001). Comparing the single photon emission computed tomographic acquisitions before and after reperfusion, Tc-MIBI activity remained unchanged in normal as well as in mildly reduced or severely reduced segments. Thus, our data are consistent with the hypothesis that Tc-MIBI traces blood flow, does not redistribute significantly despite reperfusion, and can be used for imaging the area at risk.
Restenosis after balloon angioplasty. A practical proliferative model in porcine coronary arteries.
Authors: Schwartz R S , Murphy J G , Edwards W D , Camrud A R , Vliestra R E , Holmes D R
Published: June 2011

A model of proliferative human restenosis was developed in domestic pigs by using deep injury to the coronary arterial media. Metal wire coils were delivered percutaneously to the coronary arteries of 11 pigs with an oversized, high-pressure (14 atm) balloon and were left in place for times ranging from 28 to 70 days. During placement, the balloon expanded the coils and delivered them securely within the arterial lumen. Light microscopic examination of the vessels confirmed fracture of the internal elastic lamina by the coil. An extensive proliferative response occurred in 10 of the 11 pigs and was associated with a luminal area narrowing of at least 50% in all but one pig. The histopathologic features of the proliferative response were identical to those observed in human cases of restenosis after angioplasty. Immunohistochemical studies confirmed the prominence of smooth muscle cells in the proliferative tissue. A similar response was obtained in two of five porcine coronary arteries in which balloon inflation only was performed, without coil implant. This model is practical and inexpensive and closely mimics the proliferative portion of human restenosis both grossly and microscopically. Thus, it may be useful for understanding human restenosis and for testing therapies aimed at preventing restenosis after balloon angioplasty or other coronary interventional procedures.
Massive Cerebral Infarction with Severe Brain Swelling: A CLINICOPATHOLOGICAL STUDY
Authors: NG LARRY K. Y. , NIMMANNITYA JESADA
Published: June 2011

All cases of acute supratentorial cerebral infarction which came to postmortem examination over the past 10 years at the Philadelphia General Hospital were reviewed. Of a total of 353 such cases, 45 showed severe brain swelling.

Seventy-eight percent of these 45 patients died within seven days of the acute infarction. The rapidly fatal outcome appeared to be directly related to the acute brain swelling with transtentorial herniation and brain-stem edema or hemorrhage.

In those patients who survived longer than one week following onset of the ictus (22%), clinical and anatomic findings suggested that increased intracranial pressure probably did not develop until later in the course of the illness. A second massive infarct was probably superimposed upon an earlier one and produced the acute brain swelling noted at the time of postmortem examination. Complicating visceral diseases were more common in this group and seemed to contribute to death in the majority of these patients.

Although it has been established that a large cerebral infarct may produce sufficient brain swelling and simulate an acutely expanding lesion, this is not widely recognized as playing an important part in determining the patient's clinical outcome.

The role of increased intracranial pressure resulting from acute brain swelling should not be overlooked in the management of patients with severe strokes.
Delayed Arterial Spasm and Thrombosis as a Cause of Post-Traumatic Hemiplegia (Spate Thrombosis)
Authors: JACKSON FREDERICK E. , BACK JAMES B.
Published: June 2011

The case of a Marine in whom a vertex epidural hematoma developed, depressing the superior sagittal sinus as a result of a fracture of the vertex of the skull, is presented. The hematoma was removed, and the patient did well until signs of progressive right hemiparesis suddenly developed two days after the hematoma removal. Serial carotid angiography demonstrated the interval development of spaism of the left internal carotid, anterior cerebral and middle cerebral arteries, and occlusion of the posterior parietal branch of the left middle cerebral artery. Prior to the development of the arterial spasm an earlier angiogram had shown these vessels to be of normal diameter.

This delayed or "spate" spasm and thrombosis of major intracranial vessels is a rare but serious complication of head injuries.

In addition to the usual causes of post-traumatic hemiplegias, this vascular spasm or thrombosis should be suspected in patients in whom progressive neurological signs develop after head injuries.
The Effect of Electrocautery, Atmospheric Exposure, and Surgica Retraction on the Permeability of the Blood-Brain-Barrier
Authors: HUDGINS W. R. , GARCIA JULIO H.
Published: June 2011

Alterations in the permeability to Evans-blue dye of the blood-brain-barrier were encountered in a group of squirrel monkeys that were being readied for surgical occlusion of the middle cerebral artery. Extravasation of the dye and grossly visible hemispheric cerebral swelling took place before the artery was clipped. These permeability modifications are felt to be directly related to any of the following factors: (1) use of unipolar electrocautery on the scalp and underlying muscles, (2) exertion of mechanical pressure (i.e., retraction) on the surface of the cerebrum, and (3) exposure of the arachnoid membrane and underlying cerebral cortex to atmospheric conditions for periods of up to five hours.

Previously reported experiments involving alterations in the permeability of cerebral vessels should be reevaluated in the light of the findings herein reported. Methods are described to avoid the previously mentioned artefacts on the function of the blood-brain-barrier.
Omental transposition to brain of stroke patients.
Authors: Goldsmith H S , Saunders R L , Reeves A G , Allen C D , Milne J
Published: June 2011

The intact omentum was transposed to the surface of the brain in three aphasic patients who had stabilized following a dominant hemisphere ischemic stroke. The procedure was found to be safe, causing little physical disfigurement. Subjective and objective improvement in these patients, who are on a strict experimental protocol, has provided encouragement to continue this study in a deliberate and critical manner.
Serum cardiac enzymes in stroke.
Authors: Norris J W , Hachinski V C , Myers M G , Callow J , Wong T , Moore R W
Published: June 2011

Serum cardiac enzyme levels (CK, LDH, SGOT) were estimated and the ECG recorded for 4 days following admission of 288 patients (Group I) to a stroke intensive care unit. Sixty-four of these patients, subsequently found not to have strokes, served as controls. Mean serum levels of all 3 cardiac enzymes were elevated in 8% of the 224 patients with stroke. The mean serum enzyme levels in patients with transient ischemic attacks (TIA) did not differ from controls. In a second group of 230 patients with stroke (Group II) serum CK levels were measured and the isoenzyems were fractionated to determine the tissue source of the enzymes. One hundred and one patients had raised total CK values and 25 of these (11%) had raised CK-MB (heart) iso-enzyme, the remainder having CK-MM (skeletal muscle) fraction. No serum CK-BB (brain) iso-enzyme was detected in any patient. Patients with positive serum levels of CK-MB has more evidence of acute myocardial ischemia on ECG (p less than 0.05), and more cardiac arrhythmias (p less than 0.001) than those with normal CK levels. Scattered areas of myocytolysis were found in the myocardium at autopsy in one patient. The acute rise in serum cardiac enzymes which we have recorded in the initial stages of stroke suggest that acute myocardial involvement is a commoner complication than is generally recognized. Also, since the CK-MB rises were modest and progressive, it is more likely that this acute myocardial dysfunction is a consequence, rather than a cause, of the acute cerebrovascular lesion.
pH dependence of blood-brain barrier permeability to lactate and nicotine.
Authors: Oldendorf W , Braun L , Cornford E
Published: June 2011

Brain uptake of radiolabeled D and L-lactate, D-glucose and nicotine, as measured by the intra-carotid bolus method, was examined over a range of pH of the injected solution. The uptake of L-lactate was highest at pH 6.1, and lowered significantly at pH 7.2, 7.5 and 8.4. In contrast, the uptake of the D-enantiomer was not as dramatically affected. Glucose uptake was not affected by alterations in pH. Nicotine uptake decreased with pH reduction through a range of 8.3-4.2. These data suggest that it is the uncharged molecule which penetrates the blood-brain barrier by both carrier and lipid mediation. A mechanism relating to these observations is postulated and possible relevance to lactate washout from ischemic brain discussed.
Platelet coagulant activities in arterial occlusive disease of the eye.
Authors: Walsh P N , Kansu T , Savino P J , Schatz N J , Magargal L E , Goldberg R E , Corbett J J
Published: June 2011

Ischemic optic neuropathy and retinal arterial occlusion are 2 forms of arterial occlusive disease affecting the eye. Reports in the literature suggest platelet hyperactivity in acute arterial occlusive diseases affecting other organ systems. Therefore, 14 patients with ischemic optic neuropathy and 17 patients with central or branch retinal artery occlusion were studied to determine whether platelets have a role in the pathogenesis of these vascular occlusive disorders. The results of the following investigations were no different in these patients compared with those in 18 control patients with non-vascular eye diseases: prothrombin times, partial thromboplastin times, plasma fibrinogen, factor V, factor VIII, platelet counts and threshold concentrations of ADP, epinephrine and collagen resulting in secondary platelet aggregation and serotonin release. In contrast, platelet coagulant activities concerned with the early stages of intrinsic coagulation were significantly increased in patients with retinal artery occlusion without hypertension or type IV hyperlipoproteinemia, but generally normal in patients with ischemic optic neuropathy and in patients with retinal artery occlusion associated with hypertension, type IV hyperlipoproteinemia, diabetes mellitus and generalized atherosclerosis. These results are consistent with a platelet contribution to retinal arterial occlusive disease in patients without other known contributing factors such as hypertension, serum lipid abnormalities, diabetes mellitus and generalized atherosclerosis and may have implications regarding prophylaxis.
Ischemic cerebral edema. A review.
Authors: O'Brien M D
Published: June 2011

The genesis of ischemic cerebral edema is multi-factorial and the relative importance of these many factors varies throughout the lesion and with time. The initial event is intracellular edema which may be followed by extracellular edema. This situation precludes any simple treatment, particularly because the favorable alteration of one factor might be detrimental to another.
Prevention of experimental subarachnoid hemorrhage-induced intracranial arterial vasonecrosis with phosphodiesterase inhibitor phthalazinol (EG-626).
Authors: Alksne J F , Branson P J
Published: June 2011

Experiments in monkeys have demonstrated that the chronic vasospasm and arterial injury reaction produced by subarachnoid blood injection can be prevented by treatment with the phosphodiesterase inhibitor phthalazinol. This protective effect, which is present even when the drug treatment is initiated after the subarachnoid blood injection, is presumed to occur because of the platelet inhibiting effect of phthalazinol.
Experimental cerebral vasospasm after subarachnoid hemorrhage. Participation of adrenergic nerves in cerebral vessel wall.
Authors: Endo S , Suzuki J
Published: June 2011

Distribution and morphology of nerves in basilar-artery-induced vasospasm were investigated electronmicroscopically. Small cored vesicles were transformed, decreased and disappeared gradually after development of vasospasm induced by blood-CSF mixture incubated 5--10 days. These changes were not induced by fresh arterial blood, lysed platelets in saline and mechanical stimulation. In the portion with severe vasospasm induced by incubated blood-CSF mixture, nerve distribution was rich and uniform in all portions of the adventitia. In the portion with slight vasospasm, nerves were extremely scanty in the innermost area of the adventitia, within 10 mu from the outer edge of the media. The severity of experimental vasospasm became definitely lighter and the duration shorter after bilateral cervical sympathectomy. These findings indicate that nerves, especially the adrenergic axon in the innermost area of the adventitia, may play an important role on the genesis of late vasospasm. The difference in nerve distribution may be a factor influencing individual differences in frequency or severity of vasospasm.
A gerbil model of cerebral ischemia suitable for drug evaluation.
Authors: Jarrott D M , Domer F R
Published: June 2011

Cerebral ischemia was produced in the Mongolian gerbil by bilateral occlusion of the carotid arteries. Although the cerebral ischemia so produced was not total, a mortality rate of 100% was obtained if the occlusion was maintained for 60 min in gerbils weighing 45--55 gm. Few deaths were observed after 50 min of bilateral carotid arterial occlusion. Test drugs were administered, after the removal of the arterial clips, to groups of gerbils to determine the mortality rate associated with each drug. Isoproterenol 50 mg/kg, amphetamine 5.0 mg/kg, and methylprednisolone 35 mg/kg improved survival after cerebral ischemia. Atropine 1 mg/kg, thiosemicarbazide 4 mg/kg, aminooxyacetic acid 100 mg/kg, theophylline 100 mg/kg, and phenytoin 50 mg/kg were associated with a reduced survival after cerebral ischemia. The known tendency of the gerbil to exhibit spontaneous seizures and the frequency and severity of the observed post-ischemic seizures suggest that the lethality of prolonged cerebral ischemia may be, in part, related to seizures triggered by the cerebral ischemia.
Ultrasonic demonstration of external and internal carotid patency with common carotid occlusion: a preliminary report.
Authors: Blackshear W M , Phillips D J , Bodily K C , Strandness D E
Published: June 2011

Non-invasive ultrasonic imaging of the carotid bifurcation by duplex scanning and ultrasonic arteriography combined with pulsed Doppler spectrum analysis demonstrated patency of the external and internal carotid arteries distal to a common carotid occlusion in 3 patients. Common carotid occlusion is not invariably associated with thrombosis of the ipsilateral internal carotid artery. Identification of internal carotid patency by the use of ultrasonic techniques will permit surgical treatment in selected cases.
Quantitative study of the rate of recovery from aphasia due to ischemic stroke.
Authors: Demeurisse G , Demol O , Derouck M , de Beuckelaer R , Coekaerts M J , Capon A
Published: June 2011

The extent of recovery from aphasia following ischemic stroke has been evaluated by a quantitative method. The greatest improvement was observed during the first 3 months following onset. The rate of recovery was similar for expression and for comprehension, but comprehension was usually less disturbed than expression. Final prognosis depends on the type of aphasia (the poorest prognosis was found for total or global aphasia) and on the severity of the initial insult.
Hypoxic tolerance enhanced by beta-hydroxybutyrate-glucagon in the mouse.
Authors: Eiger S M , Kirsch J R , D'Alecy L G
Published: June 2011

A coorelation has been observed between increased blood ketones and the tolerance of mice to hypoxia (4-5% oxygen). In previous studies fasted mice, alloxan diabetic mice and mice given 1,3-butanediol were found to be ketotic and to have increased tolerance to hypoxia. We attempted to induce a similar increased hypoxic tolerance by direct elevation of blood ketones with IV and IP beta-hydroxybutyrate (BHB). No increase in hypoxic tolerance was observed with BHB alone. Inasmuch as fasting and alloxan diabetes are both associated with elevated blood glucagon (G), hypoxic tolerance tests were made 30 min after G alone or a combination of G plus BHB. The mice given G alone or BHB alone had hypoxic survival times not different from saline controls. The mice given G plus BHB had increased survival times that could not be explained on the basis of a G mediated alteration in blood BHB.
Progress in cerebrovascular disease. Management of cerebral aneurysm.
Authors: Drake C G
Published: June 2011

The primary effort of neurosurgery over the past two or three decades has been to deal effectively with cerebral aneurysms surgically. Concomitantly with aggressive medical treatment, considerable progress has occurred in the prevention of early rebleeding and the treatment of the ischemic syndrome, the most serious features of the natural history of a ruptured aneurysm. The major problem now becoming evident is that in spite of this progress, the majority of patients are not seen by physicians and there has been only a small impact on the overall morbidity. It is dismaying to realize that many patients go unrecognized, at least until a massive brain-destroying hemorrhage has occurred. Only a small fraction of the patients are seen after the initial bleed when the greatest therapeutic reward would occur. The challenge for the future, then, will be the early recognition of the initial bleeding, the warning bleeding. It will require public education about the problem in a continuing fashion, as well as continuing emphasis on it for students and physicians. The potential for prevention of death or dreadful disability is large for thousands in the prime of life each year. While delayed surgery is safe, a significant amount of rebleeding and ischemia with vasospasm still occur, resulting in an unsatisfactory overall morbidity. A collaborative study is desirable to determine with sufficient patients whether very early modern operation in many hands will reduce this morbidity.
Incidence of stroke in Shibata, Japan: 1976-1978.
Authors: Tanaka H , Ueda Y , Date C , Baba T , Yamashita H , Hayashi M , Shoji H , Owada K , Baba K I , Shibuya M , Kon T , Detels R
Published: June 2011

A stroke registry was established in Shibata City, Niigata Prefecture, Japan (population 75,000) in 1976. WHO recommendations for criteria were followed. This paper reports stroke incidence for the initial 3 years of the registry: 1976 through 1978. All living patients were examined clinically by a staff physician. Only patients with a diagnosis of first stroke were included in the study. Sensitivity of the referral system was estimated at 85 + %, comparable to that in American studies. Average annual incidence per 1,000 in resident greater than or equal to 20 years was 2.61 for all strokes (3.42 for males; 1.88 for females), 0.20 for subarachnoid hemorrhage, 0.61 for cerebral hemorrhage, 1.51 for cerebral infarction - rates similar to those reported 10-20 years previously for the United States. The male-female ratio, 2:1, reflected a high rate among males, low among females. Rats among Shibata males were higher than 1972 U.S. rates reported by the Epidemiologic Study Group; rates among Shibata females were lower than corresponding U.S. rates. Incidence of all strokes combined increased with age, the age relationship being strongest for cerebral infarction. No subarachnoid hemorrhage was observed in Shibata residents greater than or equal to 70 years of age.
Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part I. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and angiogram.
Authors: Yoneda S , Nukada T , Kimura K , Tanaka K , Ashida K , Asai T , Etani H , Imaizumi M , Abe H
Published: June 2011

In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased velocity of blood flow in both the internal carotid and vertebral arteries during a contralateral carotid compression was compared with the angiographic appearance of the circle of Willis. The flow velocity was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the relationship between the increase of velocity of blood flow in the internal carotid artery and the anatomical variations of the circle of Willis, specifically the anterior cerebral and communicating arteries. The velocity of flow in the patients with an aplastic proximal portion of the anterior cerebral artery showed no increase. There were no differences in the increase of velocity of flow in the vertebral artery in patients with hypoplastic, normal and fetal posterior communicating arteries. It is considered that although anatomical variations of the circle vessels influence the cross-circulation via the circle of Willis, peripheral vascular factors distal to the circle also play an important role in the quantity of cross-circulation through the circle.
Focal cerebral hyperemia in acute stroke. Incidence, pathophysiology and clinical significance.
Authors: Olsen T S , Larsen B , Skriver E B , Herning M , Enevoldsen E , Lassen N A
Published: June 2011

In a consecutive study comprising 41 patients with completed stroke of less than 72 hours duration, cerebral angiography and measurements of the regional cerebral blood flow (rCBF) were performed within 24 hours after admission. The rCBF study was done using the 133-Xenon intracarotid injection method and a 254 multi-detector camera. CT scan was done 24 hours after the rCBF study. Focal cerebral hyperemia was found in 16 patients. The study revealed 3 different types of hyperemia: Border-zone hyperemia, surrounding ischemic areas, was seen in patients with occluded arteries on angiography, presumably resulting from accumulation of acid metabolites in the border-zone of acute infarcts. Postischemic hyperemia was seen in patients without occlusion, presumably due to recanalization of a prior occluded artery. Remote hyperemia was found distant from the infarcted area, presumably due to local tissue pressure on brain tissue. Cortical infarcts (10 patients) all had extensive hyperemic areas. Because the 254 detector camera has an excellent resolution in the cortical surface, our findings strongly suggest that all acute cerebral infarcts are, in fact, associated with hyperemic areas. The hyperemic areas are often extensive and vascular reactivity is commonly impaired. It is suggested that treatment aimed at reducing blood flow in hyperemic areas might improve prognosis.
Oxygen and glucose consumption related to Na+-K+ transport in canine brain.
Authors: Astrup J , Sørensen P M , Sørensen H R
Published: June 2011

This study examines the relation between Na+-K+ transport and metabolism in the canine brain. Cerebral oxygen and glucose consumption was measured by the sagittal sinus outflow technique. Synaptic transmission and related metabolism was blocked by pentobarbital 40 mg/kg (EEG flat). Lidocaine blocked an additional 15-20%, presumable by restricting Na+-K+ leak fluxes and reducing the demand for Na+-K+ transport. Ouabain blocked an additional 20-25% of metabolism. Ouabain also inhibited the Na+-K+ sensitive ATPase associated transport and caused a net efflux of K+ from the cellular compartment as evidenced by an increasing extracellular K+ concentration in the cortex. Accordingly, a total of 40% of metabolism in te EEG-arrested barbiturate inhibited brain could be related to Na+-K+ leak fluxes and associated transport. The remaining 60% are related to processes unidentified by this study. It is concluded that cerebral metabolism may be reduced below the hitherto described barbiturate minimum.
11C-Iodoantipyrine for the measurement of regional cerebral blood flow by positron emission tomography. Validation studies.
Authors: Ginsberg M D , Lockwood A H , Busto R , Finn R D , Campbell J A , Boothe T E
Published: June 2011

Positron emission tomography (PET) makes it possible to employ an in vivo autoradiographic paradigm to measure regional cerebral blood flow (rCBF) in man. In this study, we synthesized the positron-emitting radiopharmaceutical 11C-iodoantipyrine (11C-IAP) and validated its suitability as a CBF tracer. 11C ( T and one-half 20.4 min) was produced by the (p,alpha) nuclear reaction on 14N. 11C-methyl iodide was used to methylate 3-methyl-1-phenyl-2-pyrazolin-5-one to form 11C-antipyrine, which was iodinated. Radiochemical purity of the 11C-IAP product was 93-98% except as described below. rCBF was measured with 11C-IAP in nitrous oxide-anesthetized Wistar rats by the method of indicator fractionation, and values were compared with rCBF values measured with simultaneously administered commercially produced 14C-IAP. rCBF was studied over a range of arterial Pco2 values (31-58 mm Hg, mean 43.0 +/- 3.5). Mean rCBF data for the 2 tracers agreed to within 4.8% for cerebral hemispheral samples, 3.8% for cerebellum, and 5.3% for brainstem. Mean values (+/- SEM) for rCBF using 11C-IAP were 1.67 +/- 0.20 ml gm-1 min-1 for cerebral hemispheres; 1.32 +/- 0.17 for cerebellum; and 1.50 +/- 0.21 for brainstem. When chromatographic analysis revealed tracer impurity, rCBF, as measured with 11C-IAP, fell consistently below values obtained with 14C-IAP. The data indicate that 11C-IAP, when properly synthesized and submitted to batch-by-batch quality control, may be suitable for measuring rCBF in man by emission tomography.
Modulation of the pathophysiology of primate focal cerebral ischaemia by indomethacin.
Authors: Harris R J , Bayhan M , Branston N M , Watson A , Symon L
Published: June 2011

The effect of indomethacin (3mg/kg IA) preloading on the pathophysiology of a model of acute cerebral ischaemia has been tested. Primates anaesthetised with alpha-chloralose were used. Indomethacin reduced basal blood flow by 39% and reduced CO2 reactivity by 71%. Water content changes of the cerebral cortex and relationships between blood flow and extracellular potassium (Ke), and calcium (Cae) activities have been measured. Indomethacin infusion did not effect the water content of the left side but there was more water in all regions of the right hemisphere which were rendered ischaemic. There water increases were significant for blood flows greater than 5ml/100g/min in exposed areas. There was a significant increase in the flow thresholds for change in Ke and Cae. Possible mechanisms for these changes have been discussed.
The effects of high dose mannitol on cerebral blood flow in dogs with normal intracranial pressure.
Authors: Kassell N F , Baumann K W , Hitchon P W , Gerk M K , Hill T R , Sokoll M D
Published: June 2011

In normal dogs, bolus administration of a very high dose of mannitol (2 gm/kg) resulted in a small, transient increase in cerebral blood flow (CBF) of approximately 8 percent lasting less than 10 minutes followed by a significant reduction in CBF of approximately 20 percent lasting at least three hours. The increase in CBF may in part be related to changes in cardiovascular and hematological parameters. No explanation is available for the reduction below control values but, since urine losses were not replace in these animals, changes in the state of hydration may have been responsible. It appears that the increase in CBF resulting from mannitol administered by bolus infusion are of neither sufficient magnitude nor duration to explain the protective effect observed in other studies where cerebral blood flow was reduced below ischemic levels. This suggests then, that either the effect of mannitol on CBF is quantitatively different when flow is reduced to critical levels or that the protective effect observed when the cerebral circulation is compromised is based upon a different mechanism than augmentation of flow. Further studies on the effect of mannitol on CBF in ischemic situations, where the cerebral circulation is compromised, are required.
Problems in design of stroke treatment trials.
Authors: Spence J D , Donner A
Published: June 2011

Critical evaluation of the literature was use to identify remediable flaws in the design of clinical trials of stroke treatment. Trials of dexamethasone, dextran, and glycerol were reviewed. Available studies have in common major weaknesses in case selection (failure to exclude arteriolar strokes due to hemorrhage or lacunar infarction), and failure to estimate required sample size. Problems of case selection can be avoided with computerized tomography; the sample size required to show superiority of active treatment over placebo can be estimated using standard formulas. Prognostic stratification is suggested as a method of overcoming problems of unbalanced allocation. Further studies with improved design are required to evaluate the prospects for medical limitation of cerebral infarct size.
Evaluation of human hemispheric blood flow based on non invasive carotid blood flow measurements using the range-gated Doppler technique.
Authors: Payen D M , Levy B I , Menegalli D J , Lajat Y I , Levenson J A , Nicolas F M
Published: June 2011

Common carotid blood flow (CCBF) was measured in 11 anesthetised patients without extracranial arterial disease (nine acute subarachnoid haemorrhages and two cases of head injury). The range-gated Doppler flowmeter with an adjustable range-gated time system and a double transducer probe was used to determine diameter, blood velocity, and blood flow of the common carotid artery. Values were, respectively, 5.9 +/- 1.1 mm, 13.8 +/- 6.1 cm . sec-1 and 387 +/- 183 cm3 . min-1. Mean cerebral blood flow (rCBF) measurements were simultaneously made by 133Xenon intra-arterial method, with a value of 22.28 +/- 5.96 ml . min-1 . 100 g. High correlation coefficient was found between CCBF and mean rCBF (r = 0.73, p less than 0.001). The range-gated Doppler flowmeter thus provides a non invasive and easily duplicated method for monitoring cerebral blood flow in anesthetized patients.
Effects of promethazine on the energy metabolism of normoxic and hypoxic rat brain.
Authors: MacMillan V
Published: June 2011

The metabolic effects of intraperitoneal administration of promethazine on normoxic, hypoxemic and hypoxemic-oligemic rat brain were assessed by measurement of the cerebral contents of energy phosphates, and selected glycolytic-citric acid cycle intermediates. In normoxic brain promethazine (25-100 mg/kg-1) was associated with unaltered adenylates, increased glucose and aspartate and decreased pyruvate, lactate and malate; a pattern which was compatible with cerebral metabolic depression. Hypoxemic animals receiving either saline or promethazine (25 mg/kg-1) showed equivalent decreases in ATP and increases in lactate which indicated that promethazine had no significant effect on the metabolism of the acutely hypoxic brain. In animals exposed to hypoxemia plus right carotid artery occlusion (oligemia) the promethazine treated group (25 mg/kg-1) showed significantly lower ATP and higher AMP contents which suggested an adverse effect on the metabolism of the acutely hypoxic-oligemic brain. It is concluded that promethazine does not beneficially alter the energy metabolism of the acutely hypoxic or hypoxic-oligemic brain.
Problems of carotid Doppler scanning which can be overcome by using frequency analysis.
Authors: Johnston K W , Brown P M , Kassam M
Published: June 2011

The value of the concomittant use of a real time frequency analyzer along with a continuous wave carotid Doppler scanner is demonstrated in this study of 118 cases. With a colour-coded Doppler scanner alone, internal carotid stenoses greater than 35% were diagnosed with a sensitivity of 95% and a specificity of 82%. With the addition of frequency analysis certain inherent problems with Doppler scanning were overcome and with the measurement of the peak Doppler frequency, the specificity was improved to 93%.
Collateral cerebral vascular resistance in patients with significant carotid stenosis.
Authors: Archie J P , Feldtman R W
Published: June 2011

This study tests, the hypothesis that asymptomatic patients with hemodynamically significant internal carotid artery stenosis have a lower ipsilateral collateral cerebral vascular resistance and hence greater blood flow than their symptomatic cohorts. We measured internal carotid artery blood flow and cerebral perfusion pressures intraoperatively prior to and after carotid endarterectomy in 35 symptomatic and 10 asymptomatic patients with hemodynamically significant internal carotid artery stenosis. When the stenosis produced 30% or greater reduction in blood flow the calculated nondimensional normalized ratio of collateral cerebral vascular resistance of ipsilateral hemisphere cerebral vascular resistance was 1.15 +/- 0.83 (mean +/- SD) for the 10 asymptomatic patients and 2.98 +/- 1.89 for the 35 symptomatic patients (p = 0.0044). For the subgroup of 22 patients with 50% or greater reduction in internal carotid artery blood flow the resistance ratios were 0.782 +/- 0.541 for the 5 asymptomatic patients and 3.21 +/- 2.26 for the 17 symptomatic patients (p = 0.029). These results suggest that asymptomatic patients with hemodynamically significant internal carotid artery stenoses have a lower collateral cerebral vascular resistance than their symptomatic cohorts. The low collateral resistance may provide an adequate collateral cerebral blood flow to prevent ischemia and symptoms.
Middle cerebral artery occlusion in the young rat.
Authors: Coyle P
Published: June 2011

This investigation describes a surgical approach for ligation of the middle cerebral artery (MCA) in the young rat and evaluates consequences of the occlusion with a neurologic exam for motor deficits, Evans blue test for blood-brain barrier leaks, and light microscopy for histologic changes after 3 days. Evans blue extravasation and the lesion were limited to cortex at the burr hole site in occluded and sham operated rats. MCA occlusion beyond the point of origin of the striate branches in the young rat results in neither neurological deficits, dye markings, nor histologic changes in the distal vascular field to indicate an infarct. Apparently, the young rodent collateral supply maintains the tissue in a viable state.
Computed tomographic measurement of local cerebral blood flow by xenon enhancement.
Authors: Segawa H , Wakai S , Tamura A , Yoshimasu N , Nakamura O , Ohta M
Published: June 2011

The present technique was developed to overcome some of the disadvantages of measuring cerebral blood flow by radionuclide methods, such as poor localization of flow values and errors that result if the brain is pathological and local partition coefficients are altered. Serial CT scanning in humans was carried out during and after inhalation of 50 to 70% non-radioactive xenon. This diffusible gas with high atomic number enhanced gray matter first by 19 +/- 4 Hounsfield Units (HU) and later white matter by 24 +/- 4 HU. The regionality of flow values were cursored on CT pictures with a high spatial resolution of 4 X 4 mm (64 pixels) or 0.16cm2 X 0.5cm. In seven normal subjects, blood flow in gray matter was 82 +/- 11 ml/100gm/min and that in white matter 24 +/- 5ml/100gm/min. The partition coefficient (lambda), which is not obtainable in vivo by radionuclide scanning, was 0.9 +/- 0.1 for normal gray matter, 1.4 +/- 0.2 for normal white matter. Reduced flow, 13% in gray matter and 46% in white matter, was found in a large infarct secondary to complete occlusion of middle cerebral artery. In edematous tissue, blood flow was not significantly impaired in gray matter but was reduced to 29 to 54% in white matter. Local lambda values were reduced to 0.6-0.9 in edematous tissue, and 0.3-0.7 in infarction. This method appears to have several advantages over conventional isotope methods of measuring cerebral blood flow and provides useful clinical and research information.
Primary pontine hemorrhage and gustatory disturbance: clinicoanatomic study.
Authors: Goto N , Yamamoto T , Kaneko M , Tomita H
Published: June 2011

A clinicoanatomic study of 12 patients with tegmental-type primary pontine hemorrhage proved the presence of a gustatory disturbance among other clinical symptoms on the same side of the tongue as that of the pontine lesion, and suggested the secondary pathway of gustatory sensation from the solitary tract nucleus ascends without decussation in the homolateral pontine tegmentum. These results contradict textbook descriptions regarding the human secondary gustatory pathway.
The changing pattern of survival following stroke.
Authors: Garraway W M , Whisnant J P , Drury I
Published: June 2011

This study, compared survivorship for first episodes of cerebral infarction, intracerebral hemorrhage and subarachnoid hemorrhage which occurred in residents of Rochester, Minnesota during 5-year periods from 1945-49 through 1975-79. The progressive improvement in long-term survival following cerebral infarction which occurred between 1945-49 and 1970-74 was such that a higher proportion of patients survived for six years in 1970-74 (45%) than survived for three years in 1945-49 (42%). A modest improvement in short-term survival following cerebral infarction occurred up to 1975-79 but a marked improvement in 30-day survival following intracerebral hemorrhage was noted. The reasons for the improvement in survival have not been established, but possible changes in the diagnosis and management of stroke which might have been contributory factors are discussed.
Occlusive thromboaortopathy (Takayasu's disease): cervical arterial stenoses, retinal arterial pressure, retinal microaneurysms and prognosis.
Authors: Ishikawa K , Uyama M , Asayama K
Published: June 2011

Eighty-one young Japanese patients with occlusive thromboaortopathy (Takayasu's disease) were classed into three groups according to the degree and extent of diameter stenosis in the 4 cervical arterial systems, as determined by serial aortography. Class I was made up of 63 patients with 70% or greater stenosis in less than 3 systems, including 33 patients without systemic hypertension (Class Ia). Class II was made up of 6 patients with 70% or greater stenosis in 3 systems and less than 50% stenosis in the remaining 1, including 5 patients without systemic hypertension (Class IIa). Class III was up of 12 patients with 70% or greater stenosis in 3 systems and 50% or greater stenosis in 1 system. Ophthalmodynamometric systolic pressure in patients in Class III was significantly lower than that in patients in Class IIa (p less than 0.001), but there was no significant difference between patients in Classes Ia and IIa. Microaneurysms and/or arteriovenous anastomoses in the retinal vessels were found in all but one patient in Class III and in only one patient in combined Classes I and II. These results indicate that each of the ophthalmodynamometric values and fundoscopic findings are very helpful in identifying the markedly severe occlusive lesions (Class III) of the 4 cervical arterial systems. In this chronic disease, however, angiography is most useful for evaluation of these severe lesions, to monitor progression from Classes I and II to Class III, in which the prognosis is rather poor.
Cerebral amyloid angiopathy: incidence and complications in the aging brain. II. The distribution of amyloid vascular changes.
Authors: Vinters H V , Gilbert J J
Published: June 2011

Ten histologic sections were sampled from similar cortical regions in each of 84 autopsy brains removed from patients aged 60 to 97 years. The sections were stained by the Congo-red method and examined under polarized light for the presence of cortical (parenchymal) cerebral amyloid angiopathy (CAA). Some degree of CAA was found in 36% of all brains examined, with a higher proportion of patients affected in each successive decade of life. Angiopathy was seen most frequently and was of greater severity in the parietal and occipital gray matter. Overall, it was often a patchy and asymmetric lesion. There was sparing of subcortical white matter and the hippocampi. CAA was most severe in cases of Alzheimer's disease, but occurred in the absence of this condition.
CSF lactate and CT findings in middle cerebral artery infarction. A comparative study.
Authors: Busse O , Hoffmann O
Published: June 2011

The extent of edema related to infarction assessed by computed tomography was compared with the CSF-lactate concentration in patients with middle cerebral artery (MCA) infarction on the first, third and seventh day following the stroke. A linear correlation between the extent of infarction edema and CSF-lactate level was most distinct on the third day. CSF-lactate concentration on the third day can be considered as a measure of the extent of the accompanying edema which in our study reached its maximum at this time in comparison to the first and seventh day.
Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: incidence of stroke in Japan and Hawaii.
Authors: Takeya Y , Popper J S , Shimizu Y , Kato H , Rhoads G G , Kagan A
Published: June 2011

As part of the Ni-Hon-San Study, stroke incidence was compared in the Japan and Hawaii cohorts. Stroke cases were classified in two types, intracranial hemorrhage (ICH) and thrombo-embolic stroke (T-E). For each type the incidence in Japan was about three times as great as in Hawaii. The ratio ICH/T-E was 1/2.2 and 1/1.6 in Japan and Hawaii, respectively. Blood pressure was the most important risk factor, followed by age for total stroke in both Japan and Hawaii. Proteinuria was also a risk factor in Hawaii. Conversely, an index of animal food intake was inversely related to total stroke, significantly in Hawaii, and at a suggestive level for total and hemorrhagic stroke in Japan. Since the levels of blood pressure do not differ between Japan and Hawaii, one possible explanation for the large difference in stroke incidence between the two cohorts may be the fact that animal protein and saturated fat intake, which is inversely associated with stroke incidence, is much greater in Hawaii than in Japan. This explanation would support epidemiologic and experimental studies in Japan which suggest that dietary animal protein and fat exert an inhibitory effect on the incidence of stroke.
Prognosis in middle cerebral artery stenosis.
Authors: Corston R N , Kendall B E , Marshall J
Published: June 2011

Among 21 patients with angiographically demonstrated stenosis of the middle cerebral artery (MCA) 14 presented with a stroke and 7 with transient ischaemic attacks (TIAs). Of the former 4 had further strokes (3 fatal); of the latter one had a fatal stroke. Only 2 of the 21 patients had TIAs during the follow-up period. The present study indicates that the prognosis for patients with MCA stenosis is less good than the literature suggests. There is appreciable risk of fatal stroke especially in those who present with a stroke. This perspective is important when deciding on the need for EC/IC bypass.
Effects of mild hypercapnia on somatosensory evoked potentials in experimental cerebral ischemia.
Authors: Nakagawa Y , Ohtsuka K , Tsuru M , Nakamura N
Published: June 2011

In a previous report, the authors demonstrated the effectiveness of mild hypercapnia in enhancing decreased perfusion flow in ischemic, non-infarcted brain tissues. However, the previous work lacked in verification of improvement of suppressed brain function. Therefore, this report was attempted to evaluate the effect of hypercapnia on somatosensory evoked potential (SEP), using the similar ischemic model as previously. The results showed that mild hypercapnia of 43 to 55 mm Hg range was beneficial not only for enhancing decreased perfusion flow but also for restoring suppressed SEP. This report seems to be the first publication which verifies a presence of correlation between local cortical blood flow (LCBF) and SEP under mild hypercapnia in mildly to moderately ischemic brain tissues.
The prognostic value of noninvasive CBF measurement in subarachnoid hemorrhage.
Authors: Géraud G , Tremoulet M , Guell A , Bes A
Published: June 2011

Seventy-four measurements of cerebral blood flow (CBF) were performed using the Xenon 133 inhalation method in 50 cases of spontaneous subarachnoid hemorrhage. This method is non-traumatic, reproducible and dependable. A correlation was found between clinical condition and CBF values, but in a number of cases which cannot be dismissed, very low mean CBF values or ischemic foci were revealed where clinical state gave no indication of same. A poor correlation appeared between vasospasm seen by angiography and ischemic foci detected by isotopic technique. Patients' age influenced CBF values but not clinical evolution. CBF values, measured in the first two weeks of illness, were significantly higher in those patients having favorable outcome, whatever their clinical state at the time of CBF measurement (comas excluded). The figure of 60 ml/100g/min. for mean cortical flow seemed to be a critical level below which risk of complications was greater. Conversely, in every case where mean cortical flow measured above 70 ml, outcome was favorable. Thus, CBF measurement promises to be a valuable prognostic tool, playing an important role in the therapeutic strategy for this type of patient.