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Biomedical subjects

S Fujiwara

Publications and source records attributed to S Fujiwara.

At least 451 records · Page 25Linked to original sources
PubMed1987

Barrier disruption in the major cerebral arteries after experimental subarachnoid hemorrhage in spontaneously hypertensive and normotensive rats.

The effects of experimental subarachnoid hemorrhage (SAH) on the blood-arterial wall barrier in the major cerebral arteries were studied in 24 spontaneously hypertensive rats (SHR) and 13 Sprague-Dawley rats (SDR). Horseradish peroxidase (HRP) was given intravenously before killing the animals to assess the integrity of the barrier. In the acute experimental group, transient elevation of intracranial pressure (ICP) and systemic arterial pressure produced by cisternal injection of whole blood, saline solution, or Elliott's B solution resulted in extensive disturbance of the blood-arterial wall barrier. In the chronic group, only the cisternal injection of whole blood in SHR brought about an extensive and marked disturbance of the arterial permeability. These results suggest that: (a) early breakdown of the blood-arterial wall barrier seems to be due to a sudden rise in the ICP or arterial pressure; (b) in the chronic experiments, the subarachnoid clot is the most important factor responsible for the permeability changes; and (c) in the chronic SAH experiments, the blood-arterial wall barrier seems to be more vulnerable in SHR than in Sprague-Dawley rats. Due to the well-known similarities between SHRs and hypertensive human beings, patients with chronic hypertension should be considered at high risk after SAH for extensive blood-arterial wall barrier disturbances.

Animals↗
PubMed1987

Effect of subarachnoid hemorrhage on endothelium-dependent vasodilation.

The effect of subarachnoid hemorrhage (SAH) on endothelium-dependent vasodilation of the isolated rabbit basilar artery was examined using an isometric tension recording method. The SAH was induced by injecting 5 ml of fresh arterial blood into the cisterna magna. Sixty-two rabbits were separated into four groups according to the timing of sacrifice: control rabbits, and operated rabbits sacrificed on Days 2, 4, and 6 after SAH. Acetylcholine (ACh) (10(-7) M to 10(-4) M) and adenosine triphosphate (ATP) (10(-7) M to 10(-4) M) were used to evoke dose-dependent vasodilation of isolated arterial rings previously contracted by 10(-6) M serotonin (5-HT). There were no significant differences in the vasodilatory response to ACh among these four groups. Relaxation to approximately 84% of the initial contractile tone occurred with 10(-4) M ACh. On the other hand, the vasodilatory response to ATP was suppressed in the animals sacrificed 2 days after SAH; the relaxation of this group was approximately 52% at 10(-4) M ATP, compared to a relaxation of 87% observed in the other groups of animals. One of the major causes of the impairment of endothelium-dependent vasodilation seems to be an inhibition of the production of endothelium-derived relaxing factor by endothelial cells. After the relaxation studies, the dose-response curves for 5-HT were obtained. Serotonin caused significantly more contraction in the animals sacrificed 2 days after SAH than in the other groups. The present experiments suggest that impairment of the endothelium-dependent vasodilation following SAH, together with the potentiation of the contractile response to vasoactive agents in cerebral arteries, may play an important role in the pathogenesis of vasospasm.

Acetylcholine↗
PubMed1987

Effect of hypoxia on the contractile response to KCl, prostaglandin F2 alpha, and hemoglobin.

The purpose of this experiment was to evaluate the effect of hypoxia on the in vitro contractile responses of canine basilar artery to KCl, prostaglandin (PG) F2 alpha, and hemoglobin. Hypoxia was induced by changing the bubbling gas mixture in the chamber from 95% O2/5% CO2 to 95% N2/5% CO2. Hypoxia augmented the contractile response developed at 95% O2 to 25 mM and 50 mM KCl, 3 X 10(-7) M and 10(-5) M PGF2 alpha, and 10(-6) M hemoglobin. No significant alteration of the hypoxic augmentation in any preparation exposed to 25 mM KCl, 3 X 10(-7) M PGF2 alpha, or 10(-6) M hemoglobin was observed with guanethidine (10(-5) M), prazosin (10(-5) M), methysergide (10(-5) M), or diphenhydramine (10(-5) M). Endothelial denudation did not affect hypoxic augmentation. Hypoxia did not cause any alteration of the contractile response to 10(-6) M PGF2 alpha in Ca++-free media. Pretreatment with a calcium channel blocker, nicardipine, significantly inhibited the hypoxic potentiation of the contractile response to 25 mM KCl, 3 X 10(-7) M PGF2 alpha, and 10(-6) M hemoglobin. These results suggest that hypoxia augments the contractile response to these agonists by a direct action on the smooth-muscle cells, facilitating the transmembrane influx of extracellular calcium. Hypoxia of smooth-muscle cells in the major cerebral arteries might be involved in the pathogenesis of vasospasm.

Animals↗
PubMed1987

[Chemical embolization using conjugated estrogen--a clinical study of 40 cases].

For the treatment of dural arteriovenous malformation (AVM), meningioma and other external carotid lesions, a method of chemical embolization using a conjugated estrogen is reported. A total of 40 cases were treated, including 11 cases of dural AVM, 20 cases of meningioma and 9 other cases such as of skull tumor, aneurysmal bone cyst, nasopharyngeal tumor, traumatic AV fistula, scalp AVM and venous angioma of the scalp. The conjugated estrogen was administered continuously through a cannula inserted into the external carotid artery. For venous angioma of the scalp, it was injected directly into the lesion. Disappearance or reduction of the abnormal vasculature of the lesion and/or the feeding arteries was confirmed on angiograms in 9 of 11 cases (81.9%) of dural AVM, in 17 of 20 cases (85%) of meningioma and in all cases of other external carotid lesions. Diminution of enhancement on CT scan was obtained in 8 of 20 cases (40%) of meningioma and in 6 of 7 cases (85.7%) of other external carotid lesions. There has been no recurrence of the dural AVM as long as 10 years. Eighteen cases of meningioma were operated on, and in 16 cases the lesion was totally removed without massive hemorrhage. In 2 cases of skull tumor and a case of nasopharyngeal tumor as well, the lesions were totally removed. Complications in 40 cases were as follows: parotitis in 17 cases, liver dysfunction in 3 cases, and each of gynecomastia, facial palsy, trismus and convulsion in one case. All of them cleared up after the interruption or reduction of administration of the conjugated estrogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

[An experimental study of chemical embolization using conjugated estrogen--ultrastructural observations on rat mesenteric vessels].

We previously reported a new embolization method using conjugated estrogen and also a basic study which demonstrated that conjugated estrogen produced microcirculatory disturbance. To clarify the mechanism of this microcirculatory disturbance following the administration of conjugated estrogen, the changes of vascular endothelial cells and red blood cells were studied. After intra-arterial infusion of conjugated estrogen into rat mesenteric arteries, microcirculatory changes were observed with a biomicroscope, and also ultrastructural changes of vascular endothelial cells and red blood cells were examined. As a result, biomicroscopically, mesenteric microcirculatory disturbance in proportion to the doses of conjugated estrogens was seen and stasis of the microcirculation was finally observed in all rats. Ultrastructural observations revealed an appearance of spherocytes soon after the infusion and injury of vascular endothelial cells perfused with conjugated estrogen. Vascular endothelial cells were injured remarkably, including their plasma membrane, cytoplasm, and nuclei when mesenteric microcirculation showed sludging under the biomicroscope. At the stage of stasis, endothelial cells were severely injured and most of the vessels were filled with spherocytes. From these results, it was presumed that vascular endothelial injury and alterations of red blood cells into spherocytes induced by conjugated estrogen were the major factors of embolization effect of the conjugated estrogen. Furthermore, conjugated estrogen was considered as an effective embolic material because not only main arteries but microcirculations could be occluded by its intraarterial infusion.

Animals↗
PubMed1987

[ECG-gated magnetic resonance imaging of the left ventricle: visualization of anatomical characteristics and quantification of wall thickness and ventricular volume in left ventricular hypertrophy].

Electrocardiography- and respiration-gated magnetic resonance imaging (MRI) was performed using a 0.15-Tesla resistive magnet system in 54 patients with left ventricular hypertrophy to define the site and extent of abnormal wall thickness and to estimate left ventricular function. Because the major cardiac axes are not orthogonal to the conventional transverse, sagittal or coronal planes, the long-axis and short-axis images of the left ventricle were obtained at the end-diastolic and end-systolic phases. The anatomic characteristics of concentric hypertrophy, asymmetric septal hypertrophy, and asymmetric apical hypertrophy were clearly demonstrated by MRI, even in patients with poor echocardiographic images. Quantitatively, left ventricular wall thicknesses obtained from MR images correlated well with those obtained from echocardiography (r = 0.95), and regression was y = 0.99x + 0.39, and so did the ratios of wall thickness of the interventricular septum to the left ventricular posterior wall (r = 0.91, y = 0.80x + 0.24). Left ventricular volumes calculated by the area-length method from MRI and those from left ventriculography also correlated well (r = 0.98, y = 1.13x + 24.5). In conclusion, using the gated long-axis and short-axis MR images of the left ventricle, the anatomical location and extent of hypertrophy and left ventricular volumes are noninvasively demonstrated.

Aged↗
PubMed1987

[A case of prolactinoma in close association with Rathke's cleft cyst].

We report a case of Rathke's cleft cyst in pituitary tumor. A 31-year-old woman admitted to our hospital complained of visual disturbance, headache, amenorrhea and galactorrhea. Serum prolactin level was 3,060 ng/ml. By means of CT scan and MRI, we found suprasellar-extending tumor to have cystic component in the center of the tumor. Transsphenoidal surgery revealed grayish jelly-like content in the cyst. Histologically tumor cells were composed of chromophobic, basophilic and eosinophilic cells. The cyst wall in the pituitary adenoma was composed of ciliated or non-ciliated columnar epithelium intermingled with goblet cells, being similar to Rathke's cleft cyst. Except for the cells of the cyst wall, most of the tumor cells were immunoreactive for prolactin. As for intermediate filament, tumor cells in both solid and cystic portions showed positive immunoreactivity for cytokeratin and GFAP, and not for vimentin and neurofilament. These results suggest that the nature of the intracytoplasmic filament in the pituitary tumor with Rathke's cleft cyst may be not only keratin but also GFAP.

Adenoma↗
PubMed1987

Individual and ethnic differences in ethanol elimination.

The effects of polymorphism of aldehyde dehydrogenase (ALDH) and obesity (body weight/lean body mass) on the rate of ethanol elimination were studied. One hundred and forty subjects of healthy Japanese male volunteers who ingested 0.4 g/kg of ethanol were divided into two groups, i.e., a normal ALDH group with a low Km isozyme of ALDH and a deficient group. They were further divided into three groups in which the obesity increased in the order group A, B, C. Ethanol elimination (ER) and beta were significantly higher in the normal ALDH group than in the deficient group. In the normal ALDH subjects, beta of group C(0.187 mg/ml/hr) was higher than that of group B(0.155 mg/ml/hr). No difference in ER was observed among the three groups of the obesity in each ALDH group. Distribution volume of ethanol, r, estimated by Watson's method (0.65 to 0.89) was more accurate than Widmark's r(0.5 to 1.00). Ethanol elimination rate in the normal ALDH subjects was greater than that in Caucasian reported by other authors. Body weight was correlated well with liver weight in 135 autopsy materials.

Adult↗
PubMed1987

[Evaluation of changes in brain tissues surrounding cerebral arteriovenous malformations using NMR-CT].

Patients with cerebral arteriovenous malformation (AVM) show various clinical symptoms, but they can be divided into two groups; one resulting from rupture of AVM and another derived from chronic ischemia in surrounding tissues of AVM. Intracerebral or subarachnoid hemorrhages due to rupture of AVM can be detected by X-ray CT scan, however, it is difficult to obtain three dimensional image of changes in the surrounding area of AVM that has never experienced hemorrhagic attacks. We are using 0.15 Tesla NMR-CT (resistive type) produced by Bruker Company in West Germany and its pulse sequence is Carr-Purcell-Meiboom-Gill (CPMG) method which is best reformed type of spin echo. With this machine, we observed images of AVM and its surrounding tissue, made calculated images of T1 and T2 relaxation time and measured T1 and T2 values of ROI. On images of NMR, nidus and many dilated vessels were distinctly revealed as low or no signal intensity area in all cases without contrast media. And it is noteworthy that surrounding areas of AVM on calculated T1 and T2 images were observed as tissues showing elongated relaxation time in all cases. These tendencies were confirmed by measurement of T1 and T2 in ROI compared with contralateral side. We think elongations of T1 and T2 in surrounding tissues mean ischemic or necrotic changes in these areas induced by steal phenomena due to arteriovenous shunting.

Adult↗
PubMed1987

[Report on successful surgery of cavernous angioma in the dorsal part of the pons--usefulness of MRI in diagnosis].

A case with cavernous angioma which was located in the dorsal of the pons was cured surgically. A 16-year-old male was admitted with complaints of right motor and sensory disturbance. On neurological examination, the patient had right hemiparesis and hemiparesthesia, and right cerebellar signs. X-ray CT scan demonstrated a high density mass in the pons. Carotid and vertebral angiograms showed no abnormality. T1 and T2 weighted MRI clarified the pontine mass not as a tumor but a hematoma. Then, from the age of the patient, his clinical course, follow up X-ray CT and MRI findings, it was considered that a pontine lesion must have been an angioma with hemorrhage. Therefore, the operation was performed in an attempt to removal the hematoma and the mass of abnormal vessels in the dorsal part of the pons. Histological examination of the surgical specimen revealed abnormal vessels as a cavernous angioma. The postoperative course was uneventful.

Adolescent↗