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Biomedical subjects

T Fukushima

Publications and source records attributed to T Fukushima.

At least 343 records · Page 19Linked to original sources
PubMed1994

Comparison of benzodiazepine receptor and regional cerebral blood flow imaging of epileptiform foci in hippocampal kindled rabbits: a preliminary report.

To clarify experimentally which of benzodiazepine (BZ) receptor or regional cerebral blood flow (rCBF) imaging is more sensitive in the detection of epileptic foci, we simultaneously examined the BZ receptor and rCBF distribution changes in hippocampal kindled rabbits with in vivo double tracer autoradiography using 125I-labeled Ro 16-0154 (125I-Iomazenil) and 99mTc-labeled hexamethyl-propyleneamine oxime (99mTc-HMPAO). In visual analysis of brain slices extracted after the intravenous injection of the double tracer following the kindling completion, 125I-Iomazenil accumulation was more markedly and extensively decreased in the kindled right CA1 region mimicking a primary epileptic focus than 99mTc-HMPAO accumulation. Further, this decrease in 125I-Iomazenil accumulation was not due to neuropathological abnormalities which consisted only of tissue damage corresponding to electrode track in the right CA1. These results suggest that BZ receptor imaging is more sensitive in the detection of epileptic foci than rCBF imaging and, therefore, that BZ receptor imaging is useful in clinical epilepsy.

Animals↗
PubMed1994

Biosynthesis from gluconate of a random copolyester consisting of 3-hydroxybutyrate and medium-chain-length 3-hydroxyalkanoates by Pseudomonas sp. 61-3.

Pseudomonas sp. 61-3 isolated from soil was found to produce a polyester consisting of 3-hydroxyalkanoic acids of even carbon numbers C4, C6, C8, C10 and C12 when sodium gluconate was fed as the sole carbon source. The polyester produced was fractionated with boiling acetone. The acetone-insoluble fraction (28 wt%) of the polyester was a poly(3-hydroxybutyrate) homopolymer, while the acetone-soluble fraction (72 wt%) was composed of seven different 3-hydroxyalkanoate (3HA) units ranging from C4 to C12: 40 mol% 3-hydroxybutyrate (3HB), 5 mol% 3-hydroxyhexanoate (3HH), 20 mol% 3-hydroxyoctanoate (3HO), 24 mol% 3-hydroxydecanoate (3HD), 1 mol% 3-hydroxy-5-cis-decenoate (3H5D), 4 mol% 3-hydroxydodecanoate (3HDD) and 6 mol% 3-hydroxy-5-cis- dodecenoate (3H5DD). The copolymer was characterized by nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography and differential scanning calorimetry. The acetone-soluble fraction of this amorphous copolymer was shown to have a random sequence distribution of the seven 3HA units of C4 to C12 by analysis of the 150 MHz 13C-NMR spectrum. This is the first example of microbial synthesis of a random copolyester consisting of 3HB and medium-chain-length 3HA units.

3-Hydroxybutyric Acid↗
PubMed1994

Influence of idarubicinol on the antileukemic effect of idarubicin.

We investigated the antileukemic potency of idarubicinol (IDAol), a 13-dihydro (13-OH) metabolite of idarubicin (IDA), on the HL60 line of human leukemia cells. In contrast to daunorubicinol (DNRol) and to doxorubicinol (DOXol), IDAol showed an extensive accumulation in HL60 cells. The high affinity for DNA and the strong DNA cleavage activity of IDAol were comparable to values for IDA; consequently, IDAol was strongly cytotoxic against HL60 cells. IDAol may play an important role in the clinical efficacy of IDA in patients with acute leukemia, particularly since it persists in the blood for prolonged periods after the administration of IDA.

DNA↗
PubMed1994

Mechanism of cytotoxicity of paraquat. III. The effects of acute paraquat exposure on the electron transport system in rat mitochondria.

The effects of acute paraquat exposure on mitochondrial function in rat lung were studied. The paraquat dose-response study and time-effective study were performed to prove our hypothesis, enzyme toxicity especially in electron transport system following lipid peroxidation of mitochondrial inner membrane. In dose-response study, lipid peroxidation was increased by high dose paraquat exposure (40 mg/kg body weight) in rat lung, but not by low dose exposure (10 mg/kg body weight). But paraquat inhibited NADH:ubiquinone oxidoreductase (complex I) activities, especially NADH:ubiquinone reaction (NQR), even in low dose exposure. The lipid peroxide concentration did not correspond to the damage of complex I activity. In paraquat time-effective study, both lung and blood lipid peroxides increased after 6 h of paraquat exposure, decreased after 12 and 24 h and increased again after 48 h. After first peak of lipid peroxidation, NQR velocity decreased earlier than NADH:ferricyanide reaction (NFR) velocity. From these results, the cytotoxicity via mitochondrial dysfunction by acute paraquat exposure might be caused by complex I toxicity following lipid peroxidation of mitochondrial inner membrane.

Animals↗
PubMed1994

Antitumor effect of exogenous/endogenous TNF (EET) therapy with cyclophosphamide on C6 glioma in rat.

We earlier reported that endogenous TNF could be induced in mice as well as in patients by successive administration of exogenous TNF as a primer and OK-432 as a trigger, and we termed this exogenous/endogenous TNF (EET) therapy. We studied the effect of EET therapy with cyclophosphamide (CY) on tumor-transplanted rats. In order to induce endogenous TNF, 5 x 10(5) U/kg of recombinant human TNF-S(AM2) (rTNF; 5.6x10(6) U/mg protein) was injected intravenously (iv) as a primer followed by injection of 25 KE/kg of OK-432 as a trigger. TNF activity induced in serum was about 500 U/ml. Only 1 U/g of TNF was detected in the brain. To evaluate the antitumor effect, C6 glioma cells (1.6 x 10(4) cell/5 microliters) was transplanted into the brain. On day 7 of the transplantation, the rats were administered iv with CY (75 mg/kg), treated with EET therapy 7 days thereafter, and survival days were checked. No clear difference in survival days was observed between the rats treated with the EET and the control group. Three rats out of 6 treated with CY survived for more than 40 days, and all the rats treated with the combination of CY and EET continued to survive. The histological examination on day 44 revealed necrotic changes at the tumor lesions in all of the surviving rats, and the animals were evaluated as completely cured. These results suggest that applied treatment based on the EET therapy will be also effective against malignant brain tumors.

Animals↗
PubMed1994

Multiple intrahepatic aneurysms following transcatheter arterial embolization. Work in progress.

PURPOSE: To discuss the mechanism of multiple intrahepatic aneurysm formation after transcatheter arterial embolization (TAE) performed in five patients with hepatocellular carcinoma. MATERIALS AND METHODS: TAE was performed with gelatin sponge particles and iodized oil as embolic materials. Mitomycin C was also used in four cases. RESULTS: Three to 14 aneurysms 1-6 mm in diameter were found in third-to sixth-order branches of the hepatic arteries at repeat angiography performed 25-45 days after TAE. Follow-up angiograms in three cases revealed that most aneurysms were no longer apparent except in one patient in whom two aneurysms remained and were larger than before. In none of the five cases were any signs of aneurysm rupture noted. CONCLUSION: Radiologists should be aware of this complication of TAE. It is speculated that the main cause of aneurysm formation in these patients was the embolic agents used.

Aneurysm↗
PubMed1994

Utility of 123I-IMP SPECT brain scans for the early detection of site-specific abnormalities in Creutzfeldt-Jakob disease (Heidenhain type): a case study.

Serial changes in brain imaging of regional cerebral blood flow with single photon emission computed tomography (SPECT) using N-isopropyl-(iodine-123) p-iodoamphetamine (123I-IMP) were observed in a patient with probable Heidenhain type of Creutzfeldt-Jakob disease, which was characterized by the initial onset of visual symptoms. Corresponding to the visual signs and periodic synchronous discharges localized in the bilateral parietal and occipital regions on EEG, focal hypoperfusion images in the occipital lobes were detected on the SPECT scan before brain X-ray computed tomography and magnetic resonance imaging showed any abnormalities. These results suggest that SPECT brain imaging is useful in the early detection of site-specific abnormalities in Creutzfeldt-Jakob disease.

Aged↗
PubMed1994

Case study of monosymptomatic delusion of unpleasant body odor with structural frontal abnormality.

We report a 63-year-old man with a monosymptomatic delusion of unpleasant body odor contracted at the age of 61 years, who believed that his body reeked of some type of paint. He had symmetrical atrophy in the bilateral frontal lobes of unknown etiology on MRI. Further, quantitative rCBF measurement with SPECT brain scan using 99mTc-HMPAO showed relative hypoperfusion localized in the bilateral frontal lobes. EEG, neurological and neuropsychological tests were all normal, including the WAIS-R and Wechsler Memory Scale tests. However, he showed poor results on the Wisconsin Card Sorting test, presumably on account of frontal dysfunction, attaining only two categories with frequent perseverative errors. Although it is undetermined whether the illness in this case can be classified as organic delusional syndrome or paranoid disorder according to DSM-III-R criteria, these results imply that delusions are associated with frontal lobe abnormality.

Atrophy↗
PubMed1994

Correlations between quantitative EEG and regional cerebral blood flow (SPECT) in patients with partial epilepsy.

During interictal periods in 9 patients with partial epilepsy we examined whether there were correlations between the relative power of background EEG (power spectral analysis) and the absolute values of regional cerebral blood flow (rCBF) measured by 99mTc hexamethylpropylene amine oxime (HMPAO) SPECT in each cerebral region. None of the patients had any organic cerebral lesions on X-ray CT examinations, neurological abnormalities or mental retardation. There was an inverse correlation between rCBF and the relative power of the theta band, and a direct correlation between rCBF and that of the alpha band of 10-12.8 Hz, in the right and/or left frontal, parietal and temporal regions. In the occipital regions, there was a direct correlation only between rCBF and the relative power of the beta band. These correlations were noted whether the analyzed regions were epileptic foci or not. These results suggest that background EEG and rCBF changes in epileptic patients are closely coupled.

Adult↗
PubMed1994

Capsaicin desensitization inhibits swallowing reflex in guinea pigs.

To determine whether capsaicin-sensitive sensory nerves are involved in the swallowing reflex, we examined swallowing reflex in terms of the number of swallows elicited by injections of three different volumes (0.2, 0.4, and 0.6 ml) of distilled water, into the pharynx through a catheter in anesthetized guinea pigs pretreated with and without systemic capsaicin. The number of swallows was counted by submental electromyographic activity and visual observation of characteristic laryngeal movement. Injections of distilled water caused a volume-dependent increase in the number of swallows in animals treated with and without capsaicin. Capsaicin treatment significantly decreased the number of swallows elicited by all volumes of distilled water (p < 0.01). Exogenously administered substance P (SP) caused a dose-dependent increase in the number of swallows in all volumes but calcitonin gene-related peptide and acetylcholine were without effect. FK 888 (10(-5) M; 1 ml), a specific inhibitor of NK1 receptor, reduced the number of swallows elicited by distilled water to a similar degree as capsaicin treatment. Pharyngeal application of lidocaine (4%; 1 ml) also inhibited distilled water-induced swallowing. These results suggest that nonmyelinated C-fibers regulate the swallowing reflex through the release of SP in response to stimulation.

Acetylcholine↗
PubMed1994

Interferon-gamma increases cytoplasmic motility of alveolar macrophages via nitric oxide-dependent signaling pathways.

The effects of interferon-gamma (IFN-gamma) were investigated on cytoplasmic motility of alveolar macrophages (AM) from rat lungs in vitro. Cytoplasmic motility was examined by measuring remnant field strength from the cell surface of AM containing Fe3O4 particles, and the relaxation rate (lambda 0; min-1), which is related to cytoplasmic motility, was determined. IFN-gamma caused an increase in lambda 0 in a concentration-dependent fashion with the maximal effect at 1,000 U. Dibutyryl cyclic GMP (db cyclic GMP; 10(-3) M) mimicked IFN-gamma-induced effects, but db cyclic AMP (10(-3) M) decreased lambda 0. IFN-gamma (1,000 U)-induced increases in lambda 0 were concentration-dependently inhibited by NG-monomethyl-L-arginine (L-NMMA) with complete inhibition of a concentration of 10(-4) M and were also completely inhibited by either methylene blue (10(-5) M) or KT 5823 (10(-5) M), a specific inhibitor of protein kinase G. IFN-gamma (1,000 U) caused significant nitrite (NO2-) production from the control values of 0.2 +/- 0.1 to 10.0 +/- 0.2 microM/24 h per 10(6) cells (P < 0.001, n = 10), and this increase in NO2- production by IFN-gamma (1,000 U) was completely inhibited by L-NMMA (10(-4) M). IFN-gamma caused a concentration-dependent increase in a filamentous-actin (F-actin) content with the maximal effect at 1,000 U. db cyclic GMP (10(-3) M) mimicked IFN-gamma induced effects on F-actin formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1994

The relationship between cure depth and transmission coefficient of visible-light-activated resin composites.

The relationships between the transmission coefficient and the cure depth were evaluated on eight commercially available light-activated resin composites. The determination of transmission coefficient was carried out by the use of a radiometer for various shades of the resin composites. The transmission coefficient, ranging from 0.042 to 0.263, was dependent upon the shade of the resin. There was a good correlation between the transmission coefficient and the cure depth for different shades for each resin composite, except for one hybrid resin composite (P-50). The microfilled resin composite showed transmission coefficient and cure depth lower than those of the hybrid and small-particle-filled resin composites.

Analysis of Variance↗
PubMed1994

Microsurgical anatomy of the inner surface of the petrous bone: neuroradiological and morphometric analysis as an adjunct to the retrosigmoid transmeatal approach.

The retrosigmoid transmeatal technique remains the approach of choice for hearing preservation during the removal of acoustic neuromas that protrude from the porus acusticus. However, encroachment into the bony labyrinth in an effort to remove the tumor in the lateral end of the internal auditory canal (IAC) continues to compromise hearing in certain cases. The limits in the safe removal of the posterior wall of the IAC are not generally agreed on. To address this problem, we have performed a morphometric analysis of 32 fixed cadaveric temporal bones by microsurgical dissection and measurement with fine-cut bone window computed tomographic (CT) scans. The morphometric relationships of identifiable surface landmarks were first determined. Fine cut bone window CT scans were next performed on each bone and the distances between the fundus, the vestibule, and the common crus (CC) with the internal auditory meatus (IAM) were determined. Additionally, the thickness of the bone overlying the posterior semicircular canal at the CC was measured. From a retrosigmoid trajectory, employing a 4-cm craniotomy, the posterior wall of the IAC was removed with a high-speed drill, limiting removal to the distance from the vestibule to the IAM, as determined by CT measurement. Preservation of the integrity of deep structures was confirmed by inspection. The length of the actual IAC unroofed was measured and was compared with the IAC length, from IAM to fundus, measured by CT. The average canal length by CT measured 10.0 mm +/- 1.8 (range, 6.6-14.0). The length of the canal uncovered averaged 5.9 mm +/- 1.4 (4.0-8.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometry↗
PubMed1994

Microanatomical study of the extradural middle fossa approach to the petroclival and posterior cavernous sinus region: description of the rhomboid construct.

The extradural middle fossa transpetrosal approach has been used to access lesions of the petroclival and posterior cavernous sinus regions by several neurosurgical groups, including our own. This is a technically demanding approach that provides a relatively wide extradural corridor interposed between the 5th cranial nerve and the cranial nerve VII-VIII complex, which minimizes brain retraction. We performed a microanatomical study to determine the limits of this exposure and in particular how the removal of the petrous bone could be maximized through this approach. Dissection of 15 fixed human cadaveric heads and 8 isolated temporal bones was performed to yield 38 sides studied. We identified a rhomboid-shaped construct of middle fossa landmarks that serve as a guide to maximally removing the petrous apex. The points defining this construct are as follows: 1) the junction of the greater superficial petrosal nerve and the trigeminal nerve; 2) the lateral edge of the porus trigeminus; 3) the intersection of the petrous ridge and arcuate eminence; and 4) the intersection of the lines extended along the axes of the greater superficial petrosal nerve and arcuate eminence. A morphometric analysis determined the average lengths of the respective sides of the complex to be 13.2 mm +/- 2.6 x 22.2 mm +/- 2.8 x 16.4 mm +/- 3.4 x 16.6 mm +/- 1.5 (beginning at "1" and proceeding sequentially), with an approximate area of the construct equal to 2.9 square centimeters.(ABSTRACT TRUNCATED AT 250 WORDS)

Cavernous Sinus↗
PubMed1994

[Changes in ischemic findings in ECG, obesity and serum lipids in the residents of an agricultural area in Shimane Prefecture].

Changes in ischemic findings in ECG, obesity and serum lipids and the relations among them were investigated in Sada Town, a typical agricultural and mountaineous area in Shimane Prefecture, where the mortality rate from ischemic heart disease had increased. Compared with 1983, the percentage of ischemic findings in ECG in 1990 increased, and a marked elevation of total serum cholesterol level, and relative and absolute lowering of HDL cholesterol level were observed in 1990. By observing the relations of total serum cholesterol, HDL cholesterol and the atherosclerotic index to the ischemic findings in electrocardiograms (ECG), it was found that males showed a significantly lower HDL cholesterol level and higher atherosclerotic index than the control group. In males, a relation between obesity and ischemic findings in ECG was observed. In females, a relation between obesity and the atherosclerotic index was observed; however, no relations were observed between ischemic findings and obesity. These results support the hypothesis that a marked elevation of the total serum cholesterol level, relative and absolute lowering of the HDL cholesterol level and obesity have an effect on the recent increase of male deaths due to ischemic heart disease in Sada Town, Shimane Prefecture.

Aged↗
PubMed1994

Symptomatic Chiari malformation and associated pathophysiology in pediatric and adult patients without myelodysplasia.

The clinical characteristics of eight pediatric and five adult patients with Chiari malformation were evaluated. Six pediatric and five adult patients had associated syringomyelia. All patients initially underwent a suboccipital craniectomy with upper cervical (C-1 and/or C-2) laminectomy and duraplasty, and/or shunting procedures. The clinical characteristics of the pediatric and adult groups were compared. The mean interval between onset of symptoms and operation was shorter in the pediatric group (3 yrs 6 mos) than in the adult group (7 yrs 1 mo). Pediatric patients without syringomyelia had the shortest mean interval of 1 year 8 months. Preoperatively, the clinical features were more severe in the adult patients than in the pediatric patients. Postoperatively, seven of eight pediatric patients improved and one stabilized, while two of five adult patients improved, one stabilized, and in two the disease continued to progress despite multiple corrective procedures. Cine magnetic resonance imaging revealed correction of the abnormal cerebrospinal fluid (CSF) flow at the craniovertebral junction and decreased to-and-fro movement in the syrinx after posterior fossa decompression, which were closely correlated with the improvement of clinical features in pediatric patients. However, adult patients required further procedures because of the multifactorial nature of the disease. Evaluation of abnormal CSF pathways at the craniovertebral junction is important for investigating the pathogenesis of Chiari malformation and associated syringomyelia.

Adolescent↗