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Biomedical subjects

M Fukui

Publications and source records attributed to M Fukui.

At least 37 records · Page 2Linked to original sources
PubMed1992

Leukotriene C4 contents, synthase and catabolic activity in human meningiomas.

Leukotriene has been proposed as a factor of tumour induced brain oedema. Independently of its size, meningioma occasionally shows various extents of peritumoural oedema. We investigated LTC4 tissue contents, LTC4 catabolic and synthetic activity in 12 human meningiomas and their correlation with peritumoural oedema was studied. LTC4 contents were varied from 0.01 to 8.21 pg/mg tissue. When LTA4, an unstable expoxide intermediate was incubated with tumour homogenate, LTC4 was rapidly synthesized. However, LTC4 levels generated by incubating LTA4 with each homogenate were much different in each case. Degradation of LTC4 to LTD4, LTE4, and other polar materials was also rapid by incubation with tumour homogenates. Approximately 70% of added LTC4 was transformed to LTD4, LTE4 nor 6-trans LTB4 diastereoisomers during 30 min incubation at 37 degrees C. The results suggested that there were significant LTC4 tissue contents and LTC4 synthetic and catabolic activity in meningiomas. Oedema index ranged from 1.0 (no peritumoural oedema) to 67.5. No significant correlation, however, was observed not only between the LTC4 tissue contents and LTC4 synthetic or catabolic activities but also between each of these three parameters and peritumoural oedema. Thus, these results do not support a significant correlation of sulfidopeptide LTs with oedema formation in meningioma patients. Since leukotrienes are extremely unstable compounds, LTC4 tissue contents should be carefully discussed along with a consideration of rapid LTC4 synthesis and catabolism. Further role of leukotrienes in meningioma tissue should be studied.

Chromatography, High Pressure Liquid↗
PubMed1992

Modeling the behavior of tritiated water vapor in a research reactor containment building.

Mathematical models were developed to predict the changes in tritiated water (HTO) concentrations in water pools and of HTO vapor in the Kyoto University Reactor (KUR) containment building in which approximately 3.4 x 10(2) GBq of HTO vapor had leaked from a heavy water facility for more than 1 y. Models reveal that the mechanism of HTO vapor transfer between air and water is controlled by two key parameters: the kinetic constant for HTO exchange and the evaporation rate constant from water to air. A model was constructed based on laboratory experiments using small glass dishes containing various volumes of HTO and was validated by comparing estimates to actual measurements for HTO concentration in water pools of various depths in the containment building. After the leakage from the heavy water facility had been stopped, the decrease in HTO concentration in the sub-pool could be described by this model with a half-life of 15 wk. A mathematical model was also developed to estimate the average HTO vapor concentration in air, which is strongly dependent on the ventilation system's operation even after the removal of the HTO sources. This is due to the continued release of HTO from the concrete material and is analogous to the dynamics of radon emanation. The amount of HTO that has emerged from the concrete was estimated using a model developed for HTO concentration changes in the containment building air, based on long-term monitoring.

Air Pollution, Indoor↗
PubMed1992

The effect of serum Ca2+ compensation on the efficacy of chlorpropamide in alloxan-diabetic rabbits.

A decrease in serum Ca2+ concentration was observed in alloxan-diabetic rabbits, with recovery of serum Ca2+ levels achieved following insulin therapy. This suggested that the diabetic condition directly relates to the decrease in serum Ca2+ levels. The efficacy of chlorpropamide in alloxan-diabetic rabbits after intravenous injection (150 mumol kg-1) was less than that in normal rabbits as measured by the serum insulin levels, and the efficacy did not change when the dose was increased. However, compensation of serum Ca2+ levels in alloxan-diabetic rabbits caused an increase in the efficacy of chlorpropamide observed as an increase in serum insulin and a decrease in serum glucose levels.

Animals↗
PubMed1992

Somatosensory and spinal evoked potentials in patients with cervical syringomyelia.

We recorded somatosensory evoked potentials (SEPs) from the skin surface and spinal evoked potentials (SpEP) from the posterior epidural space after median nerve stimulation in 11 patients with cervical syringomyelia. We compared SEPs with SpEP to assess the possible feasibility of using these techniques to localize the offending lesion. SEP abnormalities were present on one or both sides of 7 patients (9 of 22 upper limbs; 41%). The abnormal SEP pattern was the attenuation or loss of N13, which was of little value for delineating the lesion. In patients with abnormal SEPs, three types of abnormal SpEPs were noted. In the Type A abnormality (three limbs), potentials were attenuated in all cervical segments, suggesting that the syrinx itself had enlarged to involve the posterior column. In Type B (two limbs), there was reduced amplitude or absent upper cervical potentials, probably a result of the accompanying tonsilar herniation. Finally, the Type C (four limbs) abnormality was a mixture of Type A and B abnormalities in that the attenuated cervical potentials were again affected in the most upper cervical segment. We concluded that SpEP revealed various kinds of involvement of the dorsal column pathway in the syringomyelic patients, a finding not expressed with conventional SEPs.

Adult↗
PubMed1992

Microsurgical and magnetic resonance imaging anatomy of the cerebello-medullary fissure and its application during fourth ventricle surgery.

The cerebellomedullary fissure, the only entrance or exit to the fourth ventricle, is surrounded rostrally by the cerebellar tonsils and the biventral lobules and caudally by the medulla oblongata, the tela choroidea, and the lateral recesses. This fissure is an important route in operations on the fourth ventricle. We studied the microsurgical and magnetic resonance imaging (MRI) anatomy of the fissure by using autopsied normal cerebellum. MRI revealed that the fissure is visible as a slit and is indicated by the enhanced choroid plexus and the flocculus. Oriented by the anatomical information thus obtained, we have surgically treated nine patients with a tumor either in or around the fourth ventricle. Preoperative MRI clearly demonstrated the tumors in relation to the cerebellomedullary fissure. It revealed the precise anatomical location and extension of the tumor, not only its inferior extension but also its lateral one. The MRI findings and microsurgical anatomy of the cerebellomedullary fissure were quite useful for the removal of the tumors in the fourth ventricle.

Aged↗
PubMed1992

Peritumoral brain edema in meningiomas--influence of vascular supply on its development.

In a series of 35 patients with intracranial meningiomas, factors influencing the development of peritumoral brain edema (PTBE) were analyzed. We used numbers of the Edema Index as the extent of PTBE, which was obtained from the size of the meningioma and associated PTBE on a T2-weighted image of magnetic resonance imaging. We evaluated a relationship between the Edema Index and some factors that may play a role in the development of PTBE. Tumors in the frontal region and at the sphenoid ridge tended to be associated with larger PTBE than those in other locations (P less than 0.05). Histologically, meningotheliomatous and transitional meningiomas tended to be associated with larger PTBE than fibroblastic meningiomas (P less than 0.05). The meningiomas that had a vascular supply from the intrinsic cerebral arteries on angiography significantly correlated with severe PTBE compared with those supplied only from the meningeal side (P less than 0.01). We concluded that location, histology, and vascular supply from intrinsic cerebral arteries were the factors influencing PTBE. It is stressed that the vascular supply from the intrinsic cerebral arteries may have an influence on the extensive PTBE of meningioma.

Blood-Brain Barrier↗
PubMed1992

Surgical treatment of moyamoya disease in pediatric patients--comparison between the results of indirect and direct revascularization procedures.

Either encephaloduroarteriosynangiosis (EDAS) or superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis combined with encephalomyosynangiosis (EMS) has been performed on most of the children with moyamoya disease in our department. EDAS alone was done in the parietal region of 13 sides in 10 patients, and STA-MCA anastomosis with EMS in the parietal region was done on 7 sides in 6 patients. The surgical results of these two different procedures were then compared. Postoperative collateral formation was observed on external carotid angiograms, and the improvement of clinical symptoms was monitored for 1 year after the bypass procedure. STA-MCA anastomosis with EMS was found to be superior to EDAS in both the development of collateral circulation (P less than 0.05) and postoperative clinical improvement (P less than 0.01). EDAS can be done easily and safely on small children with moyamoya disease, but STA-MCA anastomosis with EMS is considered to be more appropriate, whenever possible.

Cerebral Angiography↗
PubMed1992

Determination of ornithine conjugates of some carboxylic acids in birds by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the determination of ornithine conjugation of some carboxylic acids in vitro has been developed. The ornithine conjugates of benzoic acid, p-nitrobenzoic acid, furancarboxylic acid and phenylacetic acid in an incubation mixture with kidney mitochondria were well separated on a reversed-phase C18 column using a mixture of 10 mM ammonium acetate buffer and methanol as the mobile phase. In addition, by varying the pH of the mobile phase and utilizing the absorption wavelengths (nm) of the conjugates it was possible to resolve and specifically detect each conjugate. The calibration curves were linear in the range of 0.2-16 micrograms/ml for all compounds and the detection limits were about 50 ng/ml except for the ornithine conjugate of phenyl acetic acid (S/N = 2). The ornithine conjugation of some carboxylic acids with chicken kidney mitochondria were determined by this assay method. The activity of ornithine conjugation of benzoic acid, furancarboxylic acid, p-nitrobenzoic acid and phenylacetic acid were 14.5, 5.5, 0.5 and 6.9 nmol/mg of protein, respectively. Moreover, the ornithine conjugation and the glycine conjugation of benzoic acid were examined in birds and rodents. The ornithine conjugation was observed only in chicken (14.5 nmol/mg of protein) and mallard (0.99 nmol/mg of protein).

Animals↗
PubMed1992

A method to eliminate odor from recirculating air in the animal house.

A new method to eliminate odors from air recirculating in an animal house is described. The new system consists of an ozonizer and titania silica ozone decomposition catalyst in the terminal of a recirculating ventilation system. The principle underlying the elimination of odors is the oxidative reaction of malodorous components on the surface of the catalyst caused by coupling with ozonolysis. This method appeared superior in terms of its durability, efficiency and lack of resistance to air flow.

Animals↗
PubMed1992

Cystic pineocytoma--case report.

Pineocytoma and pineoblastoma, originating from pineal parenchyma, are rare and usually solid. An unusual case of totally cystic pineocytoma in a 37-year-old female is reported. The tumor showed neuronal differentiation and had a good outcome. Prominent calcification associated with pineocytoma and pineoblastoma is an useful finding to differentiate these from benign pineal cysts.

Adult↗
PubMed1992

ECM gene expression and its modulation by insulin in diabetic rats.

The steady-state levels of mRNA encoding for the alpha 1(IV) collagen chain, laminin B1 and B2 chains, basement membrane HSPG, and alpha 1(I) and alpha 1(III) collagen chains were examined in rat glomeruli at 4, 12, and 24 wk after injection of STZ. The mRNA levels for the alpha 1(IV) collagen chain, laminin B1 and B2 chains, and alpha 1(I) and alpha 1(III) collagen chains increased significantly with age in the STZ-induced diabetic rats before morphological thickening of basement membrane occurred. In contrast, the mRNA levels for HSPG decreased markedly 4 wk after STZ injection and then increased with age compared with those for control rats. The mRNA levels for these ECM components showed a continuous decline with age in controls. Treating the diabetic rats with insulin for 4 wk ameliorated the abnormally regulated ECM gene expression in the glomeruli. These data suggest that the abnormal regulation of ECM gene expression in the glomeruli may contribute to the expansion of mesangial matrix and basement membrane thickening in diabetic rats, and that hyperglycemia may play a role in the abnormal ECM gene expression.

Analysis of Variance↗
PubMed1992

[Detection of glycosylated protein of renal tissues using NBT reaction in STZ-induced diabetic rats].

We are carried out to determine the detection of glycosylated protein of renal tissues using nitroblue tetrazolium (NBT) reaction in streptozotocin (STZ)-induced diabetic rats. The levels of glomerular non-enzymatic glycosylation were measured by thiobarbituric acid (TBA) method. There was no significant difference in the intensity of NBT in renal tissues between the 4-week diabetic rats and the same age control rats. The intensity of NBT in the glomerular mesangial areas and capillary walls was marked in 12-week diabetic rats. The staining of NBT was also observed in the tubular epithelial cells in 4- and 12-week diabetic rats. The levels of glomerular non-enzymatic glycosylated protein in 4- or 12-week diabetic rats were significantly greater than those in the same age control rats. It appears that the non-enzymatic glycosylation of renal tissues increased in the early stage of diabetic nephropathy, i.e. 4- or 12-week diabetic rats. It is concluded that the non-enzymatic glycosylation may play an important role in the initiation of renal injuries in diabetic nephropathy.

Animals↗
PubMed1992

Isolated bilateral abducens nerve palsies caused by the rupture of a vertebral artery aneurysm.

We report two cases with isolated bilateral abducens nerve palsies due to the rupture of a vertebral aneurysm. Surgery revealed that the aneurysm did not directly compress the abducens nerve. Within a year after the subarachnoid hemorrhage, the patients gained full recovery from the bilateral abducens nerve palsies. In view of the clinical and operative findings, it may be regarded as a compression and/or stretching of the bilateral abducens nerves by a thick clot in the prepontine cistern, and not as a manifestation of the raised intracranial pressure. The mechanisms of the isolated abducens nerve palsy are discussed.

Abducens Nerve↗
PubMed1992

Progress on chemical knowledge of ciguatoxins.

The chemical data setted up on the ciguatoxins responsible for ciguatera fish poisonings are summarized and discussed. The multiplicity of the toxic compounds isolated from fish and algal material is described. A tentative screening of the principal toxins still on process in the two laboratories has shown that (1) CTX is dominant in carnivorous fish, (2) less polar toxins are dominant in herbivorous fish, (3) CTX precursors are produced by G. toxicus in natura and in culture conditions. The increasing polarity of the toxins in step with the food chain levels supports the hypothesis of an oxidative modification of the precursors during the bio-accumulation in fish.

Animals↗
PubMed1992

[Comparative study of brain tumors treated at China Medical University, China and Kyushu University, Japan].

We have re-examined histopathological specimens of brain tumors extirpated at China Medical University from May, 1990 to June, 1992. During the last 2 years, about 400 cases of brain tumors were operated and 349 cases were histopathologically diagnosed and classified by one of the authors (T. I). The most common tumor was meningioma, 97 cases, followed by gliomas, 87 case and neurinoma, 71 cases. The sex and age distributions of these three tumor types were compared to those of Kyushu University Hospital, Japan. The most striking difference was age of meningioma and neurinoma patients, and Chinese patients were 10 years younger than Japanese patients. The incidence of 30th age group of meningioma was 25% in China and 10% in Japan. Thirty percent of neurinoma patients were operated at 30th and 40th age in China and Japan, respectively. The sex and ages of astrocytoma patients were almost the same frequencies in China and Japan. Among 22 cases of congenital tumors, 11 cases of epidermoid tumor in cerebello-pontine cistern was included. Cerebral tuberculoma, although rarely encountered in Japan, was 2 cases in China.

Adolescent↗
PubMed1992

Microsurgical and angiographic analysis of anterior communicating artery aneurysms with associated anomalies.

A direct operation was performed on 110 patients with an aneurysm of the anterior communicating artery (ACoA). During the surgery, in 52% of the cases, the neck of the aneurysm was found at the junction of the A-1 segment and ACoA and they presented with a hypoplastic contralateral A-1 segment. Associated ACoA anomalies were seen in 13 (12%) of the 110 cases. The most common anomaly was duplication of the ACoA, found in 11 cases (10%). In 2 other cases triplicate ACoA was found. Preoperative bilateral carotid angiograms were reviewed and duplication of the ACoA associated with the aneurysms able to be pointed out on angiograms in 4 cases, retrospectively. The anatomical and radiological aspects of aneurysms with associated anomalies are also discussed.

Adult↗