Biomedical subjects

S Ibayashi

Publications and source records attributed to S Ibayashi.

At least 37 records · Page 2Linked to original sources

PubMed2001

Transcranial doppler sonography and ambulatory blood pressure monitoring in patients with hypertension.

To appraise the value of transcranial Doppler sonography (TCD) for assessment of hypertensive cerebrovascular damage, the relationship between ambulatory blood pressure (BP) and indices of cerebral circulation determined by TCD was investigated. Subjects were 55 inpatients with or without hypertension, including 13 patients with histories of cerebrovascular attacks. Mean flow velocity (MFV) in the middle cerebral artery was measured by TCD, then the cerebrovascular resistance index (CVRI; mean BP/MFV) and the Fourier PI1 (pulsatility index of the first Fourier harmonic of the flow-velocity waveform) were determined as indices of cerebrovascular resistance. CO2 reactivity of MFV was estimated as an index of cerebrovascular flow reserve. CVRI positively correlated with both daytime and nighttime BP as well as with age (p<0.01). Fourier PI1 positively correlated with nighttime BP and age (p<0.01). CO2 reactivity did not correlate with any of the ambulatory BP parameters, but negatively correlated with age (p<0.01). LV mass index significantly correlated with ambulatory BP parameters, CVRI, and Fourier PI1 but did not correlate with CO2 reactivity. Multiple regression analyses showed that nighttime systolic BP was a significant correlate for CVRI and Fourier PI1, but not for CO2 reactivity, and that history of cerebrovascular attack was significant for CVRI and CO2 reactivity. We conclude that cerebrovascular resistance determined by TCD accords with the results of ambulatory BP and LVMI, and thus could be successfully used to detect the early stage of hypertensive cerebrovascular change. Cerebrovascular flow reserve would be relatively preserved in hypertensive patients without cerebrovascular diseases.

Adult↗

PubMed2001

[YAG laser-induced reperfusion of photothrombotic middle cerebral artery occlusion in rats].

The laser-driven photochemical occlusion of middle cerebral artery(MCA) is much easier, and less traumatic than standard electrocautery or even clip methods, while the infarct size is fairly reproducible. This study aimed to establish the system for YAG laser-induced reperfusion of photothrombotic MCA occlusion. Male spontaneously hypertensive rats(5-7 months old, 350-450 g) were anesthetized with halothane, endotracheally intubated, and mechanically ventilated. The photosensitizing dye rose bengal(20 mg/kg body weight) was administered intravenously over 90 sec starting simultaneously with 3 min of krypton laser irradiation(568 nm, 20 mW). The irradiated middle cerebral artery was completely occluded by an intraluminal thrombus. A YAG laser operating at 355 nm(16 mW, 15 Hz) was focused with a cylindrical lens and positioned with a mirror onto the occluded distal MCA. This YAG laser irradiation for approximately 3 min caused reperfusion of the thrombosed distal MCA. We demonstrated a novel method of reperfusion in the photothrombotic MCA occlusion model. This reperfusion model should facilitate study of the therapeutic window for reversibility in thrombotic stroke.

Animals↗

PubMed2001

[A case of intracranial tuberculoma early diagnosed by open brain biopsy].

A 31-year-old man suffered from cough, sputum, slight fever, and loss of consciousness. He was tentatively diagnosed as epilepsy, and was transferred to our hospital. Brain CT demonstrated multiple intracranial lesions, which were homogeneously enhanced. Chest X-ray revealed retiform shadow in the right middle lung field. Pulmonary tuberculosis and intracranial tuberculomas were suspected and bacterial cultures, PCR, smear examination of sputum, blood, CSF, gastric juice, and urine were repeated. But no evidence of tuberculosis was obtained. Follow-up CT after 5 days of admission showed exacerbation of intracranial lesions. Finally, the open brain biopsy was carefully done from the right occipital lesion. The histological examination disclosed a typical pathology of tuberculoma and PCR also turned out to be positive from the brain tissue. We diagnosed him as intracranial tuberculoma and anti-tuberculous drugs(isoniazid, ethambutol, pyrazinamide) were administered. After 30 days under the medication, brain CT demonstrated a transient expansion of the intracranial lesions. While the same therapy was sustained, intracranial lesions gradually decreased and he discharged after 60 days of admission. Brain CT is known as a powerful tool for the diagnosis of intracranial tuberculoma. Its sensitivity is almost 100%, but some clinical reports have described that its specificity is not always so high(20-71%) as expected. In addition, it should be recognized that intracranial tuberculoma might show 'paradoxical expansion'. It is a phenomenon, which shows a paradoxical worsening in clinical aspect despite of the appropriate therapy. In such a progressing case as ours, it is desirable to make a definite diagnosis before anti-tuberculous drug is started. Therefore, it is recommended in possible cases to even consider the open brain biopsy from the early period when intracranial tuberculoma is highly suspected.

Adult↗

PubMed2001

Alteration of regional cerebral metabolism in patients with cirrhosis in positron emission tomography.

To evaluate the alteration of cerebral blood flow and oxygen metabolism in cirrhosis, we measured regional cerebral blood flow (rCBF), cerebral metabolic rate for oxygen (rCMRO2), and oxygen extraction fraction (rOEF) in twelve patients with cirrhosis (six with a history of hepatic encephalopathy and six without) and six age-matched controls using positron emission tomography. Regional CBF in whole brain was not different in cirrhotic patients from that in controls. In six cirrhotic patients with a history of hepatic encephalopathy, rCMRO2 was significantly lower in the frontal, temporal, parietal and occipital cortices, hippocampus, thalamus, cerebellum and brain stem, than that in each region of controls. On the other hand, rCMRO2 in six cirrhotic patients without a history of hepatic encephalopathy did not differ from the controls in all regions except for the frontal cortex. Regional OEF in cirrhotic patients without a history of hepatic encephalopathy was higher in the hippocampus and striatum than that in each region of controls. Among twelve cirrhotic patients, rCMRO2 in the occipital cortex and striatum correlated directly with plasma leucine levels, and rCMRO2 in the striatum directly correlated with plasma valine levels. Regional CMRO2 in the frontal cortex, temporal cortex, parietal cortex, white matter as well as brain stem correlated inversely with plasma phenylalanine levels, and rCMRO2 in the occipital cortex correlated inversely with plasma tyrosine levels. Brain oxygen metabolism is impaired in cirrhotic patients with a history of hepatic encephalopathy, but preserved in those without a history or in the early stage of cirrhosis. Reduced oxygen metabolism is related with altered amino acid metabolism.

Aged↗

PubMed2001

[A case of acute disseminated encephalomyelitis after renal transplantation].

We report a patient of acute disseminated encephalomyelitis (ADEM) in a recipient of renal transplantation. A 43-year-old man suffered from generalized convulsion and consciousness disturbance followed by coma on day 53 of after the transplantation. He was receiving several immunosuppressants, and an increase of serum antigen for cytomegalovirus was observed one day before the ictus. T2 and diffusion-weighted image of MRI showed high intensity lesions in the bilateral cerebral white matter, basal ganglia, thalamus, midbrain, pons and cerebellum. Examination of cerebrospinal fluid revealed elevated myelin basic protein level. The patient was diagnosed as having ADEM and was treated with methylpredonisolone pulse therapy in combination with intravenous immune globulin. He gradually recovered and became capable to eat and sit on a wheel chair. White matter lesions on MRI were also diminished. ADEM may occur in recipients of organ transplantation even if they have immunosuppressive treatment.

Acute Disease↗

PubMed2000

Hypothermia inhibits ischemia-induced efflux of amino acids and neuronal damage in the hippocampus of aged rats.

Brain hypothermia has been reported to protect against ischemic damages in adult animals. Our goal in this study was to examine whether brain hypothermia attenuates ischemic neuronal damages in the hippocampus of aged animals. We also determined effects of hypothermia on ischemia-induced releases of amino acids in the hippocampus. Temperature in the hippocampus of aged rats (19-23 months) was maintained at 36 degrees C (normothermia), 33 degrees C (mild hypothermia) or 30 degrees C (moderately hypothermia) using a thermoregulator during 20 min of transient forebrain ischemia. Cerebral ischemia increased extracellular concentrations of glutamate and aspartate by 6- and 5-fold, respectively, in the normothermic group. Mild and moderate hypothermia, however, markedly inhibited the rise of these amino acids to less than 2-fold. Elevation of extracellular taurine, a putative inhibitory amino acid, was 16-fold in the normothermic rats. Mild hypothermia attenuated ischemia-induced increase in taurine (10-fold), and moderate hypothermia inhibited the increase. Ischemic damages, evaluated by histopathological grading of hippocampal CA1 area 7 days after ischemia, was significantly ameliorated in the mild (1.3+/-0.5, mean+/-S.E.M.) and moderate hypothermic rats (0.8+/-0.3) compared with the normothermic ones (3.4+/-0.4). These results suggest that brain hypothermia protects against ischemic neuronal damages even in the aged animals, and the protection is associated with inhibition of excessive effluxes of both excitatory and inhibitory amino acids.

Aging↗

PubMed2000

Adenovirus-mediated gene transfer to cerebral circulation.

Gene therapy may, be a promising approach for treatment of cerebrovascular disease. An adenoviral vector encoding beta-galactosidase was administered intracisternally or intraventricularly into the brain of rats. Efficient expression of the reporter gene was observed at the cerebral blood vessels and perivascular tissues. When the adenoviral vector was delivered into CSF of dogs suffering from subarachnoid hemorrhage, prominent expressions of transgene were observed. Introduction of the vector to the ischemic brain of rats provided efficient transgene expression in the peri-ischemic area. Therefore, gene transfer to the cerebral blood vessel and brain may be a promising approach for gene therapy of stroke. Atherosclerotic lesion plays an important role in stroke. We evaluated efficacy of adenovirus-mediated gene transfer to the atherosclerotic vessels from monkeys and rabbits using an ex vivo gene transfer system. Efficiency of transgene expression in the atherosclerotic endothelium was better than that of normal vessels in both animals. Thus, the endothelium of atherosclerotic vessels may be a good target for gene therapy. Next, we transfected atherosclerotic carotid arteries from rabbits with an adenoviral vector encoding endothelial nitric oxide synthase (eNOS). After overexpression of eNOS in the atherosclerotic arteries, the response to acetylcholine was augmented, showing similar relaxation with normal vessels. These results suggest that gene transfer to atherosclerotic vessels improves endothelial function, which may be a new therapeutic approach for cerebrovascular disease.

Adenoviridae↗

PubMed2000

Calcium antagonist isradipine reduces metabolic alterations in acute cerebral ischemia in spontaneously hypertensive rats.

The present study was designed to examine the effect of a calcium antagonist isradipine (PN200-110: PN) on local cerebral blood flow and brain tissue metabolism after 1-hour supratentorial ischemia induced by bilateral carotid artery ligation (BCL) in spontaneously hypertensive rats (SHR). PN, dissolved in ethanol plus polyethylene glycol 400, diluted with saline to make the final concentration of 0.25mg/ml and 2.5mg/ml, was administered subcutaneously either 30 min prior to BCL or just after the induction of incomplete cerebral ischemia (n = 7 in each group). Vehicle injection was served as a control group (n = 7). Cerebral blood flow in the parietal cortex (CBF) and the cerebellar cortex (CeBF) was measured by hydrogen clearance technique, and the supra- and infratentorial metabolites of the brain frozen in situ were determined by the enzymatic method. Blood pressure was lowered, but CBF was increased by PN administration in pre-BCL treatment study. After 1 hour of BCL, CBF decreased to around 10% or less of the resting value, being insignificant among the groups. Brain adenosine triphosphate was better preserved in PN-administered groups. The increase in lactate level tended to reduce dose dependently by PN treatment. PN also reduced the metabolic alterations in brain tissue with significance, even when administered just after the induction of forebrain ischemia. It is considered that pre- as well as post-BCL administration of PN is beneficial to attenuate the metabolic alterations in incomplete forebrain ischemia in SHR.

Acute Disease↗

PubMed2000

Effect of selective brain hypothermia on regional cerebral blood flow and tissue metabolism using brain thermo-regulator in spontaneously hypertensive rats.

To investigate the effect of selective hypothermia of the brain (brain cooling) on regional cerebral blood flow and tissue metabolism, we have developed a brain thermo-regulator. Brain temperature was modulated by a water-cooled metallic plate placed on the surface of the rats' scalp to get the appropriate brain temperature precisely with ease. Regional cerebral blood flow and brain temperature were measured simultaneously using a Teflon-coated platinum electrode and thermocouple probe inserted stereotaxically into the parietal cortex and thalamus in spontaneously hypertensive rats. Experimental forebrain ischemia was induced by the occlusion of bilateral common carotid artery under normo- and hypothermic brain condition, and the supratentorial brain tissue metabolites were measured enzymatically after 60 min of forebrain ischemia. When cortical temperature was set to hypothermia, cortical blood flow was significantly lowered by 40% at 30 degree C and 20% at 33 degree C as compared with that at 36 degree C (p < 0.0001 and p < 0.05, respectively). Thalamic blood flow was also significantly reduced by 20% when cortical temperature was set to 30 degree C as compared with 36 degree C (p < 0.05). There were no significant differences in arterial blood pressure and gas parameters throughout these experiments. In the rats with selective brain hypothermia (30 degree C) immediately after the induction of cerebral ischemia, the level of brain ATP concentration after 60 min of ischemia was significantly higher than that in normothermia rats (36 degree C) (p < 0.05). Our findings indicate that: 1) the metallic plate brain thermo-regulator is useful in small animal experiments; 2) regional brain temperature regulates regional cerebral blood flow; and 3) selective brain hypothermia, even started after the forebrain ischemia, ameliorates the derangement of brain metabolism, suggesting its effectiveness as a cytoprotective strategy.

Animals↗

PubMed2000

Ovariectomy exacerbates and estrogen replacement attenuates photothrombotic focal ischemic brain injury in rats.

BACKGROUND AND PURPOSE: We previously reported the infarct volumes in female spontaneously hypertensive rats (SHR) to be significantly smaller than those in male SHR. The purpose of the present study was to determine whether estrogen is responsible for the sex difference in ischemic vulnerability in SHR. METHODS: In experiment 1, 1 week (short-term) or 4 weeks (long-term) after the ovariectomy (OVX), female SHR (5 months old) were randomly subjected to photothrombotic occlusion of the middle cerebral artery, and the infarct volumes were determined. In experiment 2, the rats were randomly assigned to 3 groups (ie, the sham-ovariectomized, ovariectomized, and estrogen replacement groups). In the replacement group, estradiol valerate (200 microgram/kg) was subcutaneously injected once a week after the OVX. Four weeks after the OVX or sham-OVX, all rats were subjected to middle cerebral artery occlusion. Changes in regional cerebral blood flow were determined by laser-Doppler flowmetry. RESULTS: In experiment 1, the infarct volume produced 1 week after the OVX was not different from that of the sham-ovariectomized group. In contrast, the infarct volume produced 4 weeks after the OVX was significantly larger than that of the sham-ovariectomized group (82.4+/-11.6 versus 54.5+/-16.0 mm(3), P=0.0058). In experiment 2, estradiol replacement after the OVX was observed to attenuate the infarct volume compared with the ovariectomized group (55.6+/-18.8 versus 78.5+/-21.0 mm(3), P=0.0321). The degrees of regional cerebral blood flow reduction did not differ among the sham-ovariectomized, ovariectomized, and estrogen replacement groups. CONCLUSIONS: Chronic estrogen depletion was thus found to increase the infarct size, which was attenuated by estradiol replacement. These findings indicate that estrogen contributes to the sex difference in ischemic vulnerability and that endogenous estrogen also has a neuroprotective effect against ischemic brain damage.

Animals↗

PubMed2000

Role of phosphatidylinositol 3-kinase in acetylcholine-induced dilatation of rat basilar artery.

BACKGROUND AND PURPOSE: We tested the hypothesis that activation of phosphatidylinositol (PI) 3-kinase is involved in dilator responses of the basilar artery to acetylcholine in vivo. METHODS: Responses of the basilar artery were measured by the cranial window technique in anesthetized rats. To examine the role of PI 3-kinase in acetylcholine-induced calcium signaling, we measured intracellular free calcium concentration ([Ca(2+)](i)) of cultured rat basilar arterial endothelial cells using a fluorescent calcium indicator, indo 1. RESULTS: -Topical application of acetylcholine (10(-6), 10(-5.5), and 10(-5) mol/L) increased the diameter of the basilar artery by 8+/-1%, 14+/-2%, and 24+/-3%, respectively. An inhibitor of PI 3-kinase, wortmannin (10(-8) mol/L), did not change the baseline diameter of the artery. In the presence of wortmannin, acetylcholine (10(-6), 10(-5.5), and 10(-5) mol/L) dilated the artery only by 3+/-2%, 6+/-2%, and 12+/-2%, respectively. Thus, wortmannin attenuated acetylcholine-induced dilatation of the basilar artery (P<0.05 versus control). Wortmannin had no effect on dilatation of the artery in response to a nitric oxide donor, sodium nitroprusside. LY294002, another inhibitor of PI 3-kinase, also inhibited dilator response of the basilar artery to acetylcholine. Acetylcholine produced an increase in [Ca(2+)](i) of the endothelial cells. Genistein, an inhibitor of tyrosine kinase, markedly attenuated acetylcholine-induced calcium influx to the cells; however, wortmannin had no effect on acetylcholine-induced calcium changes. CONCLUSIONS: These results suggest that acetylcholine-induced dilatation of the basilar artery is mediated, at least in part, by activation of PI 3-kinase in vivo. Acetylcholine-induced [Ca(2+)](i) changes of the endothelial cells may not be mediated by activation of the kinase. PI 3-kinase as well as [Ca(2+)](i) may play an important role in the acetylcholine-induced nitric oxide production of the basilar arterial endothelial cells.

Acetylcholine↗

PubMed2000

Incidence and risk factors for subtypes of cerebral infarction in a general population: the Hisayama study.

BACKGROUND AND PURPOSE: We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan. METHODS: Stroke-free subjects (n=1621) aged >/=40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings. RESULTS: The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0. 7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox's proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depression on ECG, glucose intolerance, and smoking in men and left ventricular hypertrophy on ECG and body mass index in women remained significant risk factors for lacunar infarction. ST depression was also significantly related to events of atherothrombotic infarction in women. The risk of atrial fibrillation for cardioembolic infarction was outstandingly high in both sexes, and left ventricular hypertrophy and lower total cholesterol were additional risk factors for cardioembolic infarction in women. CONCLUSIONS: In this Japanese population, lacunar infarction was the most common subtype of cerebral infarction and had a greater variety of risk factors, including not only hypertension but also ECG abnormalities, diabetes, obesity, and smoking, than did atherothrombotic infarction or cardioembolic infarction.

Adult↗

PubMed2000

Control of blood pressure and lifestyle-related risk factors in elderly Japanese hypertensive subjects.

The aim of this study was to analyze the treatment of elderly hypertensive patients by Japanese physicians specializing in hypertension. We enrolled 939 patients with hypertension who were treated in the outpatient clinics of 11 hospitals in 1995; 793 of these patients (388 men and 405 women; mean age, 66.6+/-9.0 years) received follow-up examinations in 1996, and the data on these patients was used for the present analysis. Blood pressure (BP), body mass index, lifestyle, and laboratory data were analyzed in all patients. The average BP was 143+/-16/81+/-10 mmHg in 1995 and 142+/-15/80+/-10 mmHg in 1996. The patients whose baseline BP was at the level of Grade 2 or 3 in the WHO-ISH classification (n=117) were characterized by a higher women-to-men ratio, higher age, a higher serum total cholesterol concentration, and higher QRS voltage. In these patients, from 1995 to 1996, the average BP significantly decreased, whereas fasting plasma glucose, serum total cholesterol and serum creatinine concentrations showed only negligible changes. In 220 patients (28%), BP was <140/<90 mmHg at both the initial and the follow-up examinations, whereas 351 patients (44%) were hypertensive in both 1995 and 1996. Thirty-three percent of the patients were smokers. More smokers than nonsmokers had had prior cardiovascular events, diabetes mellitus, or overt proteinuria. In conclusion, the average BP level among the patients treated by Japanese physicians specializing in hypertension was somewhat higher than that recommended by WHO-ISH Guidelines (1999). Patient education to control lifestyle-related risk factors, particularly to stop smoking, should be emphasized.

Aged↗

PubMed2000

Effects of monosodium glutamate-induced obesity in spontaneously hypertensive rats vs. Wistar Kyoto rats: serum leptin and blood flow to brown adipose tissue.

We compared the effects of hypothalamic obesity induced by neonatal monosodium glutamate (MSG) treatment between spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Newborn WKY and SHR were injected intraperitoneally with 4 mg/kg body weight of MSG daily for 5 days. At 6 months of age, the obesity of SHR was more advanced than that of WKY, but at 14 months of age the severity of obesity was similar between the two strains. Hypertriglyceridemia was enhanced in MSG-treated SHR as compared with MSG-treated WKY. Systolic blood pressure measured by the tail-cuff method was consistently lower in MSG-treated SHR than in control SHR, whereas blood pressure was not affected by neonatal MSG treatment in WKY. Food restriction reduced body weight more in control SHR than in control WKY, with the former also showing enhanced ketogenesis. Neonatal MSG treatment abolished the accelerated reduction of body weight in SHR. Serum leptin concentration was markedly increased in MSG-treated obese rats, though no differences were seen between WKY and SHR in the control or MSG-treated groups. Serum leptin was closely correlated with both Lee obese index and mesenteric fat weight over the strain. Blood flow in interscapular brown adipose tissue (BAT) measured by Laser Doppler flowmetry was significantly increased in response to beta3-adrenoceptor agonist BRL26830A in both the control and MSG-treated rats. However, the response of blood flow was not affected by MSG treatment or strain difference. The present study demonstrated some strain differences in response to neonatal MSG treatment between WKY and SHR. These differences could not be explained by the difference in serum leptin level or beta3-adrenergic reactivity in BAT.

Adipose Tissue, Brown↗

PubMed2000

Deep white matter lesions on MRI, and not silent brain infarcts are related to headache and dizziness of non-specific cause in non-stroke Japanese subjects.

OBJECTIVE: Silent or asymptomatic cerebrovascular disease is believed to be an important risk factor for symptomatic stroke and vascular dementia. Although non-specific complaints such as mild to moderate headache and/or dizziness may also be caused by silent stroke, which remains a topic of controversy. METHODS: To investigate the relationship between silent brain infarcts and non-specific complaints, we assessed findings on magnetic resonance images using a common protocol in the following three groups of subjects; Group 1:78 subjects with non-specific complaints, Group 2:47 subjects with vascular risk factors, and Group 3:75 normal subjects without any subjective complaints or vascular risk factors. In addition to silent stroke, deep white matter lesions on MRI were also evaluated. All subjects were recruited from 12 institutes of the study group located at various parts of Japan. RESULTS: Silent brain infarcts were demonstrated in 44%, 43%, and 20% of subjects in Groups 1, 2, and 3, respectively. In Group 1, the average number of infarcts per individual who had silent brain infarction was 1.8, which was significantly fewer than 3.8 in Group 2 or 3.5 in Group 3 (p<0.0167). White matter lesions were found in 68%, 49%, and 11% in Groups 1, 2, and 3, respectively, indicating that non-specific complaints are more closely related to deep white matter lesions than to silent infarct lesions. Such white matter lesions were found more frequently in subjects with depressive state than in non-depressed subjects (67% vs. 39%, p=0.0155). CONCLUSION: The present results suggest that deep white matter lesions, rather than silent brain infarcts, appear to be important in producing headache and/or dizziness of non-specific cause and also to be related to the depressive state.

Aged↗

PubMed2000

[A case of severe stenosis of bilateral distal vertebral artery successfully treated with anastomosis operation].

A 65-year-old male complained of loss of consciousness for several minutes, transient diplopia and dizziness. He had no neurological deficits nor abnormalities in MR imaging. However, flow velocity of bilateral vertebral artery on ultrasonography indicated severe stenosis of bilateral distal vertebral artery. Brain angiography revealed severe stenosis of bilateral distal vertebral artery as well as occlusion of right middle cerebral artery (MCA). Single photon emission CT (SPECT: ECD-RVR method with acetazolamide loading) showed decreased cerebral blood flow and poor perfusion reserve in bilateral cerebellar hemisphere and right MCA territory. Superficial temporal artery-superior cerebellar artery (STA-SCA) anastomosis was performed. The patient turned out to have no episodes of unconsciousness attack, transient diplopia and dizziness after operation. Cerebral blood flow (CBF) in the posterior circulation was also improved. Evaluating quantitative CBF measurement by means of ECD-RVR method was useful for evaluating CBF. In cases who have severe stenosis of bilateral distal vertebral artery with complaints of vertebrobasilar insufficiency, STA-SCA anastomosis may be one of the most effective treatments.

Aged↗

PubMed1999

Progressive motor deficits in lacunar infarction.

OBJECTIVE: To study the clinical characteristics of the progression of motor deficits in lacunar stroke patients. BACKGROUND: Some patients with lacunar infarction have progression of their neurologic deficits, but it is not known which patients will progress or why they progress. METHODS: The authors evaluated 92 consecutive patients (47 men, 45 women; age, 69.4 +/- 10.9 years [mean +/- SD]) with first-ever stroke due to supratentorial lacunes in the internal capsule or the corona radiata. By defining lacunar infarction in which motor deficits progressed between admission and the day after admission as progressive lacunar infarction, the authors compared progressive lacunar infarction with stable lacunar infarction. RESULTS: Of 92 patients, 25 (27%) had progression of deficits. Diabetes mellitus (p = 0.02) and severity of motor deficit on admission (p = 0.006) were related independently to progression in a logistic multiple regression analysis. Size of the infarct was slightly larger (1.2 +/- 0.4 cm2 versus 0.9 +/- 0.5 cm2; p = 0.01) and functional status at discharge was worse (median Barthel index, 45 versus 100; p < 0.001) in patients with progressive infarction than in those without progression. There were no significant differences between the two groups regarding the site of the infarct or blood pressure or hematocrit levels on or after admission. CONCLUSIONS: The progression of motor deficits is associated with a relatively poor functional outcome. Diabetes mellitus and the severity of motor deficit on admission may predict progression of motor deficits.

Activities of Daily Living↗

PubMed1999

Hemodialysis causes severe orthostatic reduction in cerebral blood flow velocity in diabetic patients.

Orthostatic hypotension is a serious problem in patients with diabetes mellitus (DM) undergoing hemodialysis (HD). To evaluate cerebral circulation during orthostasis in patients with DM, we examined changes in mean blood flow velocity in the middle cerebral artery (VMCA) during 60 degrees head-up tilt for 5 minutes in patients with DM (six men, two women; age, 57 +/- 3 years [mean +/- SEM]; HD duration, 47 +/- 27 months) before and after bicarbonate HD by using transcranial Doppler sonography. The findings were compared with those in HD patients without diabetes (non-DM; 12 men, 5 women; age, 47 +/- 3 years; HD duration, 82 +/- 23 months). Mean blood pressure (MBP) in the supine position, hematocrit (Hct), plasma fibrinogen, and volume of fluid removed by HD were not significantly different between the two groups (MBP, 106 +/- 6 versus 103 +/- 4 mm Hg; Hct, 26% +/- 1% versus 28% +/- 1%; fibrinogen, 355 +/- 37 versus 357 +/- 27 mg/dL; fluid, 2.5 +/- 0.2 versus 2.3 +/- 0.2 L). Percentage of change in VMCA (% VMCA) during tilt was compared between the groups before and after HD. Before HD, MBP decreased significantly to 93 +/- 5 mm Hg during tilt only in patients with DM. The degree of MBP reduction was -13 +/- 2 mm Hg in DM and -2 +/- 2 mm Hg in non-DM patients (P < 0.01). % VMCA equally decreased during tilt; DM, -12% +/- 3%, and non-DM, -12% +/- 2%. After HD; MBP decreased by 36 +/- 7 mm Hg in patients with DM, which was significantly greater than before HD. VMCA also decreased in both groups after HD, and % VMCA in DM (-32% +/- 5%) was significantly greater than before HD (P < 0.01) and in non-DM patients (-13% +/- 2%; P < 0.01). % VMCA positively correlated with the percentage of change ratio of MBP during tilt in both groups after HD (DM, r = 0. 87, P < 0.01; non-DM, r = 0.61, P < 0.01). Our results showed a significant decrease in cerebral blood flow velocity during tilt of equal magnitude in both groups before HD despite differences in the level of hypotension, whereas reduction in cerebral blood flow velocity and decrease in MBP were more marked in DM after HD. Orthostasis could thus cause hemodynamically mediated brain damage after HD, especially in patients with DM.

Aged↗