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Biomedical subjects

S Nishio

Publications and source records attributed to S Nishio.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Radiation-induced leiomyosarcoma of the dura mater: a case report].

A 31-year-old man underwent total resection for a fibrillary astrocytoma in the right frontal lobe followed by 6MV x-ray radiotherapy. The portal field size was a square of 8 cm x 7 cm, and the total dose of irradiation was 50Gy, with single fractions of 2Gy. For the next 6.5 years there was no recurrence of the astrocytoma. At 38 years of age, the patient noticed a subcutaneous mass in the scar of the previous operation and developed generalized convulsive seizures. MRI revealed a dural tumor within the previous radiation field, and the tumor was partially removed. Histologically, it was diagnosed as a leiomyosarcoma. This dural sarcoma satisfies the widely used criteria for definition of radiation-induced malignancies first described by Cahan et al. Both the clinical features and the possible histogenesis of this secondary tumor are briefly discussed.

Adult↗
PubMed1996

Glial tumourettes (glial microtumours): their clinical and histopathological manifestations.

This study represents our experience with eight cases (males: 4; females: 4; 13-47 years old, average age 28.5 years) of a "glial tumourette" (minute glioma), which measured less than 15 mm in diameter on an MRI. Four tumours were located in the frontal lobe, one in the rostrum of the corpus callosum, two in the midbrain, and one in the thalamus. The symptoms and signs lasted from two days to 15 months prior to diagnosis, and they consisted of epileptic seizures in five patients and increased intracranial pressure due to hydrocephalus resulting from aqueductal stenosis in three. All patients had a CT scan and an MRI as a part of their initial neuroimaging evaluations. While the CT findings failed to show the lesion in four patients, MRI demonstrated it in all cases. Five tumours were either totally or subtotally removed while the remaining three were biopsied. Histological examinations revealed six tumours to be low-grade gliomas (fibrillary astrocytoma: 4; oligoastrocytoma: 2) and two to be high-grade gliomas (anaplastic astrocytoma: 1; anaplastic oligodendroglioma: 1). Regarding adjuvant therapy, three patients received radiation and/or chemotherapy. One of the patients with midbrain fibrillary astrocytoma died of the disease 38 months after the operation, however, no evidence of progression in the remaining seven has been observed in the follow-up period ranging from five to 65 months after the operation (average: 25.4 months). The histogenesis of benign and malignant gliomas and the importance of surgical exploration in the management of such patients with minute intracerebral tumours are also discussed.

Adolescent↗
PubMed1996

Effects of beraprost sodium, a prostacyclin analogue, on tail flick response in two models of diabetic-neuropathy in rats and its mechanism.

The effects of beraprost sodium (BPS), a stable prostacyclin analogue, on the tail flick (TF) latency were investigated in streptozotocin-induced (STZ;55mg/kg, i.p.) diabetic male Sprague-Dawley (SD) rats and in spontaneously diabetic WBN/Kob rats. The SD rats were divided into 5 groups, i.e., (I) normal, (II) diabetic control, diabetic treated with (III) BPS (10 micrograms/kg/day), (IV) BPS (30 micrograms/kg/ day), and (V) aldose reductase inhibitor (ARI; epalrestat, 50 micrograms/kg/day). The drugs were administered orally. At 12 weeks, TF latency was significantly longer in untreated diabetic rats than in normal rats. After 4 weeks treatment, BPS significantly improved the abnormality in TF latency dose-dependently. But ARI did not normalize the response. The 45 weeks male WBN/Kob rats were divided into 2 groups: diabetic control and diabetic treated with BPS at 30 micrograms/kg/day, p.o., respectively. Untreated, age-matched wistar rats were served as the normal group. At 61 weeks, TF latency was significantly longer in control WBN/Kob rats than in normal wistar rats in time-dependent manner. After 16 weeks treatment, BPS significantly normalized the prolongation in TF latency. In in vivo experiments, BPS significantly increased the cyclic AMP (cAMP) content in sciatic nerves from normal rats dose-dependently. In STZ-induced diabetic rats, cAMP content in sciatic nerves were significantly reduced, and 4 weeks treatment of BPS significantly restored this reduced cAMP content. It was suggested that BPS may be effective on diabetic neuropathy by, at least in part, maintenance of cAMP contents in the nerves.

Animals↗
PubMed1996

Positive inotropic and chronotropic effects of beraprost sodium, a stable analogue of prostacyclin, in isolated guinea pig myocardium.

1. Inotropic and chronotropic effects of beraprost sodium (beraprost), a chemically stable prostacyclin analogue, were examined in isolated myocardial preparations of guinea pigs. 2. In the left atria, 10(-9) - 10(-7) M beraprost had no significant effect on the contractile force, but 10(-6) and 10(-5) M produced a concentration-dependent positive inotropic response. This effect was antagonized by S-145, a potent and selective thromboxane A2 (TXA2) receptor antagonist, but not by propranolol. 3. Beraprost, from 10(-9) to 10(-5) M, had no significant inotropic effect in the right ventricular papillary muscles. 4. In the right atria, 10(-9) and 10(-8) M beraprost had no significant effect, but 10(-7) - 10(-5) M caused an increase in beating rate; this effect was not affected by S-145. 5. The present study demonstrates that beraprost has positive inotropic and chronotropic effects at high doses on isolated guinea pig atria. The inotropic effect may be mediated by the TXA2 receptor, but some mechanism other than the TXA2 receptor is responsible for the chronotropic effect.

Adrenergic beta-Antagonists↗
PubMed1996

Effects of beraprost sodium and prostaglandin E1 on skin blood flow in diabetic rats and normal dogs.

1. The present study was undertaken to compare the effects of beraprost sodium (BPS), a stable prostaglandin I2 analog, with prostaglandin E1 (PGE1) on the skin blood flow in anesthesized diabetic rats and anesthetized dogs. 2. In anesthetized diabetic rats, BPS, but not PGE1, caused a dose-dependent and significant increase in femoral skin blood flow. 3. In anesthetized dogs, PGE1 significantly increased femoral arterial blood flow than BPS. However, BPS significantly increased in-step skin blood flow than PGE1. 4. The above data suggest that BPS may be clinically useful for the treatment of circulatory insufficiency of lower extremities in diabetic patients.

Alprostadil↗
PubMed1996

Magnetoencephalographic features in neurocysticercosis.

BACKGROUND: Magnetoencephalography (MEG) is a method of determining the brain activity noninvasively be detecting the magnetic fields associated with neuronal electrical activities. METHODS: By using 37-channel DC-superconducting quantum interference devices, MEG activity was recorded in a patient with neurocysticerosis, who had a long-term history of epilepsy. RESULTS: MEG clearly demonstrated accumulation of current dipoles originating from high-frequency waves around the cysticercal cyst, while scalp electroencephalogram failed to reveal paroxysmal discharge. Intraoperative electrocorticography revealed multiple spike activities around the lesion, consistent with MEG findings. CONCLUSIONS: We discussed the application of MEG to the patients with neurocysticercosis in estimating epileptogenic sources.

Adult↗
PubMed1996

Protective effect of beraprost sodium, a stable prostacyclin analogue, in development of monocrotaline-induced pulmonary hypertension.

Experimental pulmonary hypertension (PH) was induced by a single injection of monocrotaline (MCT), a pyrrolizidine alkaloid extracted from Crotalaria spectabilis. The effect of beraprost sodium, a stable prostacyclin analogue, on the development of MCT-induced PH in rats was studied. Chronic administration of beraprost sodium at a dose of 30 micrograms/kg/day initiated on the same day as MCT injection decreased the degree of PH determined by weight ratio of right ventricular free wall to that of left ventricle plus septum depending on the duration of administration. Although the injection of prostaglandin E1 (PGE1) at a dose of 200 micrograms/kg/day initiated 1 week after MCT injection did not decrease the degree of PH significantly, beraprost sodium administration at doses of 30 and 100 micrograms/kg/day decreased the degree of PH significantly. The cytoprotective effect of beraprost sodium against endothelial cell (EC) damage is believed to be involved in inhibiting development of PH in MCT-injected rats. The amounts of cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF) produced by alveolar macrophages decreased in accordance with the inhibiting effect of beraprost sodium on development of PH, indicating that beraprost sodium inhibited the development of PH in MCT-injected rats not only through its effect of vasodilation and anti-platelet aggregation in pulmonary circulation but also through its antiinflammatory effects.

Alprostadil↗
PubMed1996

Multicentric pleomorphic xanthoastrocytomas: case report.

We report the case of a 22-year-old woman who developed multicentric pleomorphic xanthoastrocytomas (PXAs) in the cerebral hemisphere. She underwent a first operation for a PXA in the right parietal lobe at the age of 7 years and a second operation at the age of 15 years in the right frontal lobe, remote from the previous tumor site. At age 22 years, she was found to have a tumor, which was a newly formed PXA, in the left occipital lobe. There was no recurrent tumor in the right frontal lobe. Clinical and pathological aspects of multicentric PXAs are reviewed and discussed.

Adolescent↗
PubMed1996

Pharmacokinetic study of zonisamide in patients undergoing brain surgery.

To test whether the concentration of the anticonvulsant zonisamide in erythrocytes reflects the brain concentration and the clinical response of the drug, its pharmacokinetics were studied in nine patients undergoing surgery for brain tumour. Erythrocyte, total and free serum concentrations in samples drawn on the day of brain surgery were compared with levels on a day after the operation. In three patients zonisamide and its major metabolite, 2-sulphamoylacetylphenol, were also analysed in urine. The area under the curve of the free and the erythrocyte concentration did not differ between the two study phases whereas the area under the curve of the total serum concentration was significantly lower on the day of the operation, and this was associated with significant increases in total clearance (15.4 compared with 12.7 mL kg-1 h-1, P < 0.05, n = 9) and renal clearance (5.4 compared with 3.3 mL kg-1 h-1, P < 0.05, n = 3), and non-significant change in non-renal clearance (7.7 on the day of operation compared with 8.4 mL kg-1 h-1 on the post-operation day, n = 3). Zonisamide distribution was also altered by the operative procedure, as evidenced by a higher volume of distribution (1.48 compared with 0.87 L kg-1, P < 0.05, n = 9). The binding of zonisamide was characterized on both days. Zonisamide binding to erythrocytes seemed to occur by two processes: a saturable process and a non-saturable linear process. The maximum binding capacity to erythrocytes (31.6 vs 29.7 micrograms mL-1) did not differ on the two days; however, increases in the dissociation binding constant (+28%) and the proportionality constant (+24%) were observed on the day of the operation, suggesting that the zonisamide concentration in erythrocytes was greater on the day of the operation. Brain surgery appears to be one of the possible factors altering the rate of elimination of zonisamide and the uptake of the drug by erythrocytes.

Adult↗
PubMed1996

Noninvasive measures of oxidative metabolism on working human muscles by near-infrared spectroscopy.

The purpose of this study was to determine whether the initial rate of hemoglobin and myoglobin deoxygenation during immediate postexercise ischemia, a reflection of muscle O2 consumption (VO2mus), can be a quantitative measure of muscle oxidative metabolism. The finger flexor muscles of five healthy men (aged 25-31 yr) were monitored by 31P-magnetic resonance spectroscopy for changes in phosphocreatine (PCr), Pi, and pH. Tests were conducted during 15 min of cuff ischemia and during 5 min of submaximal isotonic grip exercise at 10, 20, 30, and 40% of maximal voluntary contraction, one contraction every 4 s. The VO2mus changes were also monitored by near-infrared spectroscopy with continuous wave. The VO2mus during exercise was expressed relative to the resting value. The resting metabolic rate, calculated from the PCr breakdown rate after complete O2 depletion, was 0.0010 (SD) mM ATP/s. During submaximal exercise (pH > 6.9), the VO2mus increased with a rise in intensity (0.036 +/- 0.011, 0.054 +/- 0.016, 0.062 +/- 0.012, and 0.067 +/- 0.020 mM ATP/s during 10, 20, 30, and 40% maximal voluntary contraction, respectively) and showed significant correlation with changes in both calculated ADP and PCr values (r2 = 0.98 and r2 = 0.99, respectively). In conclusion, because of the significant correlation with regulatory metabolites (ADP and PCr) of oxidative phosphorylation, O2 decline rate in immediate postexercise ischemia determined by near-infrared spectroscopy with continuous wave can be utilized for the quantitative evaluation of localized muscle oxidative metabolism.

Adult↗
PubMed1996

Effects of beraprost sodium, a prostacyclin analogue, on diabetic neuropathy in streptozotocin-induced diabetic rats.

The effects of beraprost sodium (BPS), a stable prostacyclin analogue, on motor nerve conduction velocity and nerve blood flow of the sciatic nerve were investigated in streptozotocin-induced diabetic rats, and they were compared with the effects of epalrestat (aldose reductase inhibitor). Treatment with BPS for 4 weeks significantly inhibited the decrease in motor nerve conduction velocity and nerve blood flow dose-dependently, but epalrestat had no effect on nerve blood flow. Morphological changes of the myelinated fibers of the sciatic nerve were observed macroscopically. The mean axonal area and the mean circularity index of diabetic control rats were significantly less than that of normal rats, while after 6 weeks of BPS treatment, these decreases of the axonal area and the circularity index were inhibited. The enlargement of the mean lumen area of microvessels in the diabetic rats was significantly inhibited after 6 weeks of BPS treatment. Additionally, augmentation of the washed platelet aggregation in diabetic rats was significantly normalized by BPS. It was suggested that BPS is effective on diabetic neuropathy via amelioration of the decrease of blood supply to the structure. The effects of BPS on platelets might also contribute to the improvement of neuronal circulatory deficiency.

Animals↗
PubMed1996

Cellular and metabolic basis of Clara cell tolerance to multiple doses of cytochrome P450-activated cytotoxicants. I: Bronchiolar epithelial reorganization and expression of cytochrome P450 monooxygenases in mice exposed to multiple doses of naphthalene.

The objectives of this study were to quantitatively define alterations in the epithelial populations and expression of cytochrome P450 monooxygenases in distal airways which are associated with the tolerance resulting from repeated exposure of mice to the acute Clara cell toxicant, naphthalene. Bronchiolar epithelium of mice treated daily for 7 days with an acutely cytotoxic dose of naphthalene (200 mg/kg/day) quantitatively resembles the bronchiolar epithelium of control animals in terms of proportions of ciliated and nonciliated cells and nuclear and cytoplasmic volumes. Subsequent treatment of tolerant animals with higher doses (300 mg/kg) does not produce the same Clara cell injury observed in previously untreated mice after a single treatment with 300 mg/kg. After repeated exposures to naphthalene, cellular expression of immunoreactive cytochrome P450 monooxygenases 2B and 2F, P450 reductase and Clara cell secretory protein significantly decreased in bronchiolar epithelium. Although metabolism of naphthalene to the 1R,2S-naphthalene oxide is depressed in microsomes derived from whole-lung homogenates of tolerant animals, metabolism of naphthalene in distal airways isolated by microdissection is unchanged from the controls at saturating substrate concentrations. When substrate concentrations are less than the apparent K(m) for naphthalene (< 0.05 mM), the rate of naphthalene metabolite production is markedly lower in distal airways of tolerant mice compared with controls. Covalent binding of reactive naphthalene metabolites in lungs of tolerant mice is also unchanged from control. In conclusion, after repeated exposure to short-term cytotoxic doses of naphthalene distal bronchioles of tolerant mice 1) are lined by epithelium which resembles that of controls; 2) express lower levels of P450 proteins; 3) have reduced levels of naphthalene monooxygenase activity, but only at less than saturating concentrations and 4) have no decrease in covalent binding of reactive metabolites to proteins.

Animals↗
PubMed1996

Intracranial epidural abscess: late complication of allograft cranioplasty.

A case of intracranial epidural abscess, 20 years after allograftic cranioplasty was presented. The abscess was caused by bacterial implantation after a minor stab wound of the scalp over the cranioplastic plate. It seemed quite rare that the intarcranial abscess occurred 20 years after an allograftic cranioplasty.

Abscess↗
PubMed1995

Spontaneous resolution of hypertrophic cranial pachymeningitis.

A 36-year-old woman presented suffering from severe headache and diploia. Magnetic resonance imaging showed a diffuse thickening of the cranial dura mater which was enhanced by gadolinium-DTPA. Two months later, an improvement of the clinical symptoms and a spontaneous resolution of the dural thickening were noted. Hypertrophic cranial pachymeningitis and other diseases causing diffuse dural thickening are discussed.

Adult↗
PubMed1995

Cholesterol granuloma in the middle cranial fossa: report of two cases.

We report two cases of cholesterol granuloma in the middle cranial fossa. On CT the lesions appeared as a nonspecific, nonenhancing soft-tissue mass with bone erosion. On MRI they were seen as areas of high signal intensity surrounded by a low-intensity peripheral zone on both T1- and T2-weighted images. Cholesterol granuloma is thought to occur when pneumatised cells in the temporal bone become obstructed. Although this lesion usually occurs in the petrous bone, it can extend to the middle cranial fossa. The diagnosis and surgical management are discussed.

Adult↗
PubMed1995

A new saxitoxin analogue from a xanthid crab Atergatis floridus.

A novel paralytic toxin was isolated from toxic specimens of a xanthid crab Atergatis floridus inhabiting the Pacific coast of Shikoku Island. Its structure was deduced to be 11-saxitoxinethanoic acid (SEA) based on high-performance liquid chromatography, electrospray ionization mass spectrometry, and 1H and 13C-NMR spectrometries. This acid was assumed to exist as an equilibrium mixture of three tautomers, the main tautomer being the hydrate form 11 beta-epimer. SEA showed a specific toxicity of 830 mouse units per mumole on i.p. injection into mice.

Acetic Acid↗
PubMed1995

Chemotherapy for progressive pilocytic astrocytomas in the chiasmo-hypothalamic regions.

Over the past 25 years, we have treated 17 patients with chiasmo-hypothalamic astrocytomas. Before 1988, the initial treatments consisted of surgery and/or radiotherapy, while since 1989, 4 children (1 male, 3 females, aged 3-8 years) were treated primarily with chemotherapy. None of them was associated with neurofibromatosis. After a biopsy of the tumor, the intravenous administration of ranimustine (MCNU; 30-86 mg/m2) and/or nimustine (ACNU; 30.3-64.1 mg/m2) was given without radiation therapy. Chemotherapy was usually given as an out-patient, with a total of 5-13 courses. The total doses of MCNU and ACNU administered ranged from 150 to 570 mg and from 64.8 mg to 100 mg, respectively. After chemotherapy 2 patients showed clinical improvement and tumor regression on neuro-imaging, while one patient showed clinical improvement and tumor size stabilization on neuro-imaging. The remaining one child, however, showed a clinical worsening and tumor progression on neuro-imaging studies. He was thus treated with a second chemotherapy regimen with carboplatin and etoposide, which brought about tumor regression. The acute and subacute toxicity of chemotherapy was mild. All patients are now leading almost normal lives with a median of 43 months after diagnosis. Although a longer and more careful clinical observation is required, the authors conclude that chemotherapy with MCNU and/or ACNU may benefit patients with unresectable pilocytic astrocytoma requiring treatment. The advantages of this therapy include its mild side effects and the lack of any hospitalization in most patients. It may also delay the need for radiation therapy, which can have a deleterious effect on the young developing brain.

Antineoplastic Agents↗