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Biomedical subjects

K Minematsu

Publications and source records attributed to K Minematsu.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Homolateral ataxia and crural paresis following anterior cerebral artery territory infarction].

Homolateral ataxia and crural paresis (HACP) is defined as predominantly crural paresis with ipsilateral ataxia, a variant of ataxic hemiparesis (AH), by Fisher and his colleagues. HACP usually resulted from lacunar infarction in the basis pontis at the junction of the upper one-third and inferior two-third of the pons, or in the posterior limb of the internal capsule. We reported a patient with HACP which was caused by an infarct in the paracentral gyrus irrigated by the anterior cerebral artery (ACA). He had had no cerebellar signs before the onset of HACP, although he had old small infarcts in the right pons, right thalamus and left cerebellar hemisphere. Neuroimaging and other clinical studies suggested that the mechanism of the present infarction was the most-likely embolic, but not lacunar. As far as we know, there has been only one abstract presentation of a patient with HACP due to ACA territory infarction in Japan, although five such cases were recently reported by Bogousslavsky and others.

Aged↗
PubMed1998

A novel AMPA receptor antagonist, YM872, reduces infarct size after middle cerebral artery occlusion in rats.

The neuroprotective effect of YM872 ([2.3-dioxo-7-(1H-imidazol-1-yl) 6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl]acetic acid monohydrate), a novel alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonist with improved water solubility, was examined in a rat focal cerebral ischemia model. Rats were subjected to permanent middle cerebral artery (MCA) occlusion using the intraluminal suture occlusion method for 24 h. YM872 was intravenously infused for 4 h (20 and 40 mg/kg/h) or 24 h (10 and 20 mg/kg/h), starting 5 min after the MCA occlusion, to investigate the effect of prolonged duration of the treatment on infarct volume. In the 4 h infusion study, YM872 reduced the cortical infarct volume by 48% at a dose of 40 mg/kg/h. YM872 did not significantly reduce the infarct at 20 mg/kg/h for 4 h. In the 24 h infusion study, however, YM872 markedly reduced the cortical infarct volume by 62%, even at 20 mg/kg/h. The present study indicates that the neuroprotective effect of YM872 is enhanced by extending the duration of treatment, and demonstrates the benefit of the prolonged treatment with AMPA antagonists following focal cerebral ischemia. YM872, a highly water soluble compound, is applicable to investigate the role of AMPA receptors in ischemic models without concern about nephrotoxicity and could be useful in the treatment of human stroke.

Animals↗
PubMed1998

Oscillating thromboemboli within the extracranial internal carotid artery demonstrated by ultrasonography in patients with acute cardioembolic stroke.

We detected oscillating thromboemboli at the extracranial internal carotid artery (ICA) by duplex carotid ultrasonography in patients with acute cardioembolic stroke. Using B-mode ultrasonography, we evaluated the extracranial ICA in 11 patients with acute cardioembolic ICA occlusion. A homogeneous, elastic, oscillating intraluminal mass echo originating in the extracranial ICA extended distally in 5 (46%) of these patients. The echoes moved quickly and distally during the systolic phase of the cardiac cycle and returned slowly to the original position during the diastolic phase. We performed a postmortem study 24 days after stroke onset in 1 patient with an oscillating intraluminal mass echo that had been demonstrated by duplex ultrasonography. The ICA lumen was obstructed with a fresh string-like thrombus. The findings of oscillating intraluminal mass echo may help establish a diagnosis of acute embolic ICA occlusion.

Acute Disease↗
PubMed1998

Side-to-side differences of the common carotid artery diameter in presence of asymmetry of the circle of Willis or different vasculopathies.

Based on angiographic and carotid ultrasonographic findings in 60 patients with stroke or other diseases, we studied what factors affected the side-to-side differences of the common carotid artery diameter (CCAD). The side-to-side differences of the CCAD were within 0.7 mm in patients with normal cerebral angiogram, but a difference above 0.7 mm was found in many patients with asymmetry of the circle of Willis or different vasculopathies, such as the carotid artery occlusion, cerebral arteriovenous malformation and aortitis.

Aortitis↗
PubMed1998

CMDME (curved mesh diagram of mandibular excursion) method for visualization and diagnosis of mandibular movement.

The CMDME (curved mesh diagram of mandibular excursion) method was developed for easy visualization and diagnosis of mandibular movement. This method uses measured mandibular movement to produce a diagram of the range, shape, and inclination of mandibular excursion in three dimensions using any arbitrary landmark of the mandible. First, the mandibular movement of a subject was measured by an opto-electronic movement analysis system capable of measuring mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. For the measurement, the subject was initially instructed to perform four repetitions of mandibular excursion at will, with tooth contact, each lasting 30 s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an attempt was made to match these positions to intersection points (0.1 mm apart) of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal position at the origin. The CMDME method can visualize mandibular excursion, and can be used to compare several landmarks, different subjects, or different times. This makes this method an effective diagnostic tool for mandibular movement.

Adult↗
PubMed1998

Effect of acetazolamide reactivity on [corrected] long-term outcome in patients with major cerebral artery occlusive diseases.

BACKGROUND AND PURPOSE: It remains unclear whether hemodynamic insufficiency plays a major role in ischemic events. We performed a prospective follow-up study in ischemic stroke patients with occlusive large-artery diseases to determine whether stroke recurrence is related to reduced vasodilatory capacity, judged with single-photon emission CT and acetazolamide (ACZ) challenge. METHODS: During the period from 1987 to 1995, we examined cerebral vasodilatory capacity with single-photon emission CT and an ACZ challenge in 105 consecutive stroke patients with severe stenosis (> 75% in diameter) or occlusion of the internal carotid artery or the trunk of the middle cerebral artery who had no or minimal infarcts on CT. According to criteria reported earlier, the patients were divided into two groups: normal (negative ACZ, n = 50) or reduced ACZ reactivity (positive ACZ, n = 55). They were prospectively followed at regular intervals for a median period of 2.7 years. RESULTS: The Kaplan-Meier analysis revealed no difference in cumulative recurrence-free survival rate between the two groups. The multivariate analysis with Cox proportional hazards model demonstrated that a high systolic blood pressure at entry into the study significantly increased stroke recurrence (coefficient = .0466; hazard ratio = 1.0477; 95% confidence interval = 1.0017 to 1.0957; P = .04), whereas antihypertensive medication significantly reduced stroke recurrence (coefficient = -1.527; hazard ratio = 0.217; 95% confidence interval = 0.0612 to 0.771; P = .02), but no other variables including ACZ reactivity affected stroke recurrence rate. CONCLUSIONS: The present results demonstrate that reduced vasodilatory capacity does not play a major role in stroke recurrence. Antihypertensive therapy appears to reduce stroke recurrence even in patients with hemodynamically significant arterial diseases.

Acetazolamide↗
PubMed1998

Transoral carotid ultrasonography.

BACKGROUND AND PURPOSE: We attempted ultrasonographic evaluation of the distal extracranial internal carotid artery (ICA) using the transoral method (transoral carotid ultrasonography [TOCU]). METHODS: The subjects consisted of five healthy volunteers and seven stroke patients. Examinations were performed with a color Doppler flow imaging system equipped with convex array transducers (7 or 9.5 MHz), originally designed for transrectal use. After local anesthesia of the pharynx, we inserted a probe covered with thin gum transorally, touching the tip to the pharyngeal posterolateral wall. We then attempted to detect the ICA and measure flow velocity of the distal extracranial ICA using principal images obtained by TOCU. RESULTS: TOCU was successfully performed in all subjects without any difficulty. In the healthy volunteers, the ICA was identified at a depth of 2.2+/-0.6 cm and visualized as a vertical linear vessel 2.9+/-0.3 cm in length and bent slightly backward. The diameter and mean flow velocity of the distal extracranial ICA were 4.7+/-0.2 mm and 50+/-7 cm/s, respectively. In the stroke patients, some remarkable findings were obtained, including a narrow ICA with low flow velocity in a patient with possible ICA dissection, a lucent echo without flow signal in a patient with acute cardioembolic ICA occlusion, and decreased ICA flow velocity in a patient with ipsilateral MCA stenosis. CONCLUSIONS: These preliminary data demonstrate the potential applicability of TOCU to the evaluation of flow in the far distal extracranial ICA. TOCU definitely warrants further investigation in patients with carotid artery disease.

Adult↗
PubMed1998

Differences in clinical features and computed tomographic findings between embolic and non-embolic acute ischemic stroke: a quantitative differential diagnosis.

A diagnosis based on the presumed mechanism of stroke onset is useful for management strategies in acute ischemic stroke. Ninety-two patients with embolic (cardiac or artery-to-artery) and 107 with non-embolic (thrombotic or hemodynamic) stroke were diagnosed on strict cerebral angiographic criteria alone. To clearly discriminate between these two groups, the neurological and computed tomographic (CT) findings were then compared. Rapidity of onset, vomiting, urinary incontinence, level of consciousness, cervical bruit, anisocoria, tongue deviation, sensory disturbance, and CT findings (location of hypodense area, findings of brain edema and hemorrhagic transformation) were discriminatory factors between the two groups (p<0.01). According to these 11 items, we prepared a numerical table for quantitative differential diagnosis. A diagnostic accuracy of 98.9% for embolic and 87.9% for non-embolic stroke in internal verification, and 90.0% and 82.9%, respectively, in external verification was observed. The differences in clinical features and CT findings between embolic and non-embolic stroke may reflect the pathophysiological mechanisms of the occlusive process of cerebral artery as well as the extent and severity of ischemia.

Acute Disease↗
PubMed1998

Successful application of three-dimensional transcranial power Doppler imaging in two stroke patients.

We applied a new technique of three-dimensional (3-D) transcranial power Doppler imaging to demonstrate the middle cerebral artery (MCA) in the 2 stroke patients. In the first patient, the 3-D power Doppler study clearly showed the horizontal portion, bifurcation, proximal portion of the upper and lower trunks, and the major branches of the lower trunk of the MCA. In the second patient, the 3-D power Doppler clearly revealed the proximal bifurcation of the left MCA. The 3-D transcranial power Doppler seems to be useful in making clear 3-D images of the MCA.

Cerebral Angiography↗
PubMed1998

[Pathophysiology and treatment of cardioembolic stroke].

To elucidate the pathophysiologic mechanism of cardioembolic stroke in elderly people and to devise therapeutic strategies for it, was analyzed 120 consecutive patients (77 men and 43 women aged 65 +/- 13 years) with acute cardioembolic stroke who were admitted within 7 days of the stroke onset. We compared underlying heart diseases. NIH stroke scale on admission, lesion size on computed tomography (CT), the relation between anticoagulant therapy and recurrence, complications during admission. ADL at discharge, recurrence, and death during the follow up period in three groups: patients aged less than 65 years (the young group), those aged from 65 to 74 years (the "non-old" group), and those aged more than 75 years (the "old old" group). In the "old old" group, non valvular atrial fibrillation (75.8%) was the most common underlying heart disease and so was rheumatic heart disease (33.3%) in the "non-old" group. NIH stroke scale score (median, 11) and the proportion of patients with a large lesion (> 3 cm) of CT were higher in the "old old" group than in the other two groups. Immediate anticoagulation (A/C) within 14 days of onset was performed in more than 70% of the "non-old" and the "young old" groups but in only 57.6% of the "old old" group. Stroke recurred more often in 34 patients who did not receive immediate A/C than in the 86 who did (11.8% v.s. 2.3%. Chi square test, p = 0.053). Hemorrhage during immediate A/C and other complications (infection and pulmonary embolism) were seen in 2 and 14 patients, respectively, in both the "young old" groups, but not in the "non-old" group. Good outcomes (able to walk with or without cane) were more common in the "non-old" group (78.9%) than the other groups (57.1%, Chi square test, p < (0.01). A/C after the acute stage was done in more than 80% of those in the "non-old" and the "young old" groups, but in less than 30% of those in the "old old" group (Chi square test, p = 0.0514). Survival without recurrence during the observation period (605 +/- 550 days) was significantly lower in the "old old" group than in the other two groups (log-rank test, p = 0.0091). Cardioembolic stroke in the elderly may be characterized as follows: (1) non valvular atrial fibrillation is the most common, (2) severe neurologic deficits on admission and large lesions on CT are noted, (3) complications (infection and pulmonary embolism) often occur, (4) A/C in both acute and chronic stages are done infrequently. Therefore, the indication and intensity of A/C for primary and secondary prevention and prevention of complications are important in management of cardioembolic stroke in the elderly.

Age Factors↗
PubMed1998

Blood flow measurement during distraction osteogenesis.

The regional blood flow of 30 distraction segments in 27 patients was measured during distraction osteogenesis. There were three groups of patients. Group A consisted of seven patients with high grade malignant tumors who received chemotherapy preoperatively and postoperatively. Group B consisted of eight patients with low grade malignant and aggressive benign tumors, who all were treated without chemotherapy. Group C (the control group) consisted of 12 patients with nontumoral conditions. Using quantitative technetium scintigraphy, the regional blood flow within the distracted segment and surrounding soft tissues was measured. The measured radioisotope count was expressed as the ratio of the distracted site to the control site (blood flow ratio). The blood flow ratio for all the cases averaged 1.70 +/- 0.70. Group A had a lower blood flow ratio, which was statistically significant in comparison with the other two groups. The external fixation index showed no significant difference in callus formation among these three groups. No correlation was found between the blood flow ratio and external fixation index. Chemotherapy decreases regional blood flow, but with distraction osteogenesis the regional blood flow can be kept within the normal range or higher. Distraction osteogenesis may overcome the effects of chemotherapy by increasing blood flow.

Adolescent↗
PubMed1998

[Panhypopituitarism following basilar artery dissection with extensive brainstem and cerebellar infarction: a case report].

We experienced a patient with panhypopituitarism which occurred following extensive brainstem and cerebellar infarction due to dissection of basilar artery (BAD). Panhypopituitarism followed by BAD has not yet been reported in the literature. The patient was a 67-years-old man who was admitted to our hospital because of a sudden onset of consciousness disturbance and vomiting. On the day of admission, he was drowsy and had left IIIrd nerve palsy, skew deviation, occular bobbing, and left hemiparesis. His neurological state was rapidly deteriorated, and fell almost into apneic state, requiring artificial ventilation for a week. Cerebral angiography demonstrated a double lumen sign of the basilar artery confirming the diagnosis of dissection. There were extensive hypodensities in the brainstem and bilateral cerebellar hemispheres on CT. On day 20, he suddenly became shocked following infection. Even after the effective and successful treatment of infection, severe hypotension continued that required administration of chatecholamine agents. Laboratory examinations revealed that he had panhypopituitarism. Supplement therapy with adrenocortical hormones made his circulatory state improved, and could finally be stopped on day 100. In the present case, subclinical hypopituitarism was considered to occur mainly from compression of the pituitary stalk and hypothalamus by the enlarged BAD. Increased intracranial pressure and upward herniation may also have made the pituitary function worse, and the infection finally triggered the adrenal crisis. The BAD occurs more frequently than previously considered, and should be kept in mind as a cause of secondary panhypopituitarism.

Aged↗
PubMed1998

[Right-to-left shunt and atrial septal aneurysm in stroke patients: a contrast transesophageal echocardiographic study].

BACKGROUND: Transesophageal echocardiography (TEE) has been used to detect cardiac abnormalities including right-to-left shunt (RLS) and atrial septal aneurysm (ASA). The aim of this study was to elucidate frequency of RLS and ASA detected by contrast-TEE, and to evaluate the role of these abnormalities in stroke patients. METHODS AND RESULTS: We investigated prevalence of RLS and ASA in 504 patients suspected of stroke by using TEE. (mean age 62 +/- 12 y.o., stroke 491, non-stroke 13). The RLS was detected in 64 patients (12.7%), in whom 49 patients (9.7%) had the patent foramen ovale (PFO). The ASA was demonstrated in 10 patients (2.0%), and accompanied well with the RLS (six of the 10, 60%). The prevalent ratios of the RLS (33.8%), the PFO (26.8%), and the ASA (11.3%) in 71 patients with embolic stroke (brain embolism or TIA) of unknown cause were significantly higher than those in the other 433 patients (9.2%, 6.9%, 0.5%, respectively, p < 0.0001). Multiple logistic regression analysis showed that both the PFO and the ASA were independent risk factors (odds ratio: 3.8: p = 0.0002 and 16.6: p = 0.0008, respectively) for embolic stroke of unknown cause. CONCLUSION: It seems that the RLS, PFO and the ASA play a roll in developing embolic stroke of unknown cause.

Adult↗
PubMed1998

[Disappearance of embolic signals on transcranial Doppler sonography following antiplatelet therapy in a patient with transient ischemic attacks].

Transcranial Doppler sonography (TCD) has been increasingly used to detect embolic signals. A 49-year-old woman had repeated episodes of weakness and numbness of the right limbs. She was diagnosed as having transient ischemic attacks (TIAs). A cranial Gadolinium-enhanced MRI revealed multiple small lesions in the cortical-subcortical areas of the left middle cerebral artery territory. A TCD examination on admission detected 4 embolic signals on the left MCA trunk in a 30-minute examination period. TIAs completely ceased after the initiation of an antiplatelet therapy with aspirin. Embolic signals were not detected in later TCD studies. The embolic signals on the TCD strongly indicated that TIAs are caused by an embolic mechanism. TCD is potentially useful for assessing the efficacy of antiplatelet and anticoagulant therapies in patients with TIAs.

Aspirin↗
PubMed1997

Positron emission tomography for quantitative determination of glucose metabolism in normal and ischemic brains in rats: an insoluble problem by the Harderian glands.

To examine the reliability of quantitative positron emission tomography studies in the rat (Rat-PET), we assessed the influence of radioactivity accumulated in the Harderian glands on PET CMRglc determination. We measured CMRglc by PET and ex vivo dissection methods by using 2-[18F]fluoro-2-deoxy-D-glucose in rats with and without focal brain ischemia. The CMRglc values obtained by PET, after correcting with recovery coefficients, were higher than those measured by the ex vivo method at rostral slices, and reduction of the CMRglc in the ischemic brain was not demonstrated by PET in the frontal cortex. The radioactivity accumulated in the Harderian glands prevents the quantitative determination of CMRglc using Rat-PET.

Animals↗
PubMed1997

A Japanese family with a variant of Gerstmann-Sträussler-Scheinker disease.

OBJECTIVE: A new variant of Gerstmann-Sträussler-Scheinker disease (GSS) was reported, which had a substitution of glutamate to lysine at codon 219 (E219K) in addition to a P102L mutation on the same allele of the PrP gene. However, clinical features were not detailed and pathological studies were not done. Unusual clinical, neuroradiological, and pathological findings are reported for these patients. METHODS AND RESULTS: Clinical presentations of the patients in the same family were variable; progressive dementia with minimal ataxia in some patients but ataxia without dementia in others. PET studies with 18F-2-fluoro-2-deoxyglucose (FDG) disclosed a relative decrease of FDG uptake in bilateral temporoparietal cortices of a patient with dementia, but in the cerebellar cortices in a patient with ataxia. At necropsy, a patient with dementia had multicentric and diffuse plaques stained with PrP antiserum, but not with haematoxylin and eosin or Congo red, in the cerebral and cerebellar cortices. CONCLUSION: Neurological and neuropathological features in the patients were atypical of the classic form of GSS with P102L mutation. The absence of Congo red staining prion protein plaques is probably attributable to E219K polymorphism on the same allele of the PrP gene.

Adult↗
PubMed1997

Predisposing factors to enlargement of spontaneous intracerebral hematoma.

BACKGROUND AND PURPOSE: Enlargement of intracerebral hemorrhage is a major cause of clinical deterioration. Identification of factors that predispose to hematoma enlargement is important in managing patients. METHODS: We selected 186 patients (71 women and 115 men; mean age, 64.8 +/- 12.5 years) with spontaneous intracerebral hemorrhage who had undergone an initial CT within 24 hours and a second scan within 120 hours of symptom onset. We compared patients with (n = 41) and without (n = 145) hematoma enlargement according to clinical characteristics and laboratory data. RESULTS: By multiple logistic regression analysis (n = 139), interaction of long interval (> 6 hours) from onset to first CT and small hematoma (< 25 cm3) strongly reduced risk of enlargement. The analysis also demonstrated that the following factors independently predisposed to enlargement: history of brain infarction; liver disease; interaction of fasting plasma glucose > or = 141 mg/dL and systolic blood pressure on admission > or = 200 mm Hg; and interaction of glycosylated hemoglobin A1c > or = 5.1% and systolic blood pressure on admission > or = 200 mm Hg. CONCLUSIONS: A patient examined > 6 hours after ictus who has a hematoma volume < 25 cm3 is unlikely to experience further hematoma growth. Prevention of brain infarction and premorbid management of liver disease may serve to lower the risk of hematoma enlargement. Although it remains controversial whether antihypertensive drugs should be used in the acute phase of intracerebral hemorrhage, poorly controlled diabetics with high systolic blood pressure (> or = 200 mm Hg) on admission also were at high risk of hematoma enlargement.

Aged↗