Biomedical subjects

T Hishinuma

Publications and source records attributed to T Hishinuma.

At least 55 records · Page 3Linked to original sources

PubMed1996

Effects of clofibrate on flow cytometric populations in rat liver.

A flow cytometric study was performed on the liver of normal and clofibrate-treated rats. The flow cytometric patterns of these fractions showed three distinct populations (R1, R2 and R3). The R3 region was remarkably increased in the clofibrate-treated nuclear fraction, and was applied to sucrose linear density gradient centrifugation. Mt1, Mt2, Mt3 and Mt4 fractions were isolated and reacted with rhodamine-123. An essential enzyme for beta-oxidation, delta 3, delta 2-enoyl-CoA isomerase, was mainly expressed in Mt1 of the control-nuclear fraction, but not in Mt1, Mt2 and Mt4 in the clofibrate-treated nuclear fraction. These results suggest that clofibrate affects the flow cytometrical population of the mitochondria and changes the expression level of beta-oxidation enzyme(s) of the mitochondria in rat liver.

Animals↗

PubMed1995

Microdetermination of the prostaglandin B1 in human plasma by gas chromatography/selected ion monitoring using [18O]prostaglandin B1 as an internal standard.

We devised a simple and effective purification for the microdetermination of prostaglandin B1 (PGB1), a metabolite of PGE1. [18O]PGB1 was synthesized by the repeated base-catalyzed hydrolysis of methyl ester derivatives in H(2)18O, to obtain an internal standard for the gas chromatography/selected ion monitoring (GC/SIM) of PGB1. The methyl ester-methoxime-dimethylisopropylsilyl ether derivative was prepared, then GC/SIM was carried out by monitoring the ion at m/z 448.3 for PGB1 and that at m/z 452.3 for internal standard. A good linear response over the range of 10 pg to 100 ng was demonstrated. We detected PGB1 to a level of about 40 pg/mL in human plasma. This method can be used to determine PGB1 in biological samples.

Adult↗

PubMed1995

Positron emission tomography (PET) study of the alterations in brain distribution of [11C]methamphetamine in methamphetamine sensitized dog.

[11C]Methamphetamine ([11C]MAP) was synthesized by an automated on-line [11C]methylation system for positron emission tomography (PET) study. We newly produced a MAP sensitized dog by repeated MAP treatment and studied the brain distribution of [11C]MAP in the normal and the MAP sensitized dog. The maximal level of accumulation of [11C]MAP in the sensitized dog brain was 1.4 times higher than that in the control. No difference was found in the metabolism of MAP between the two conditions. The significant increase of [11C]MAP in the MAP sensitized brain indicates that subchronic MAP administration causes some functional change in uptake site of MAP.

Animals↗

PubMed1995

Identification of 11-dehydro-2,3-dinorthromboxane B3 in human urine based on the mass spectral properties of 11-dehydrothromboxane B3 and related compounds.

11-Dehydro-2,3-dinorthromboxane B3 (an enzymatic metabolite of TXB3) was identified. Urine from a healthy male adult who had received daily administration of 1.8 g (0.6 g three times) of eicosapentaenoic acid (EPA) ethyl ester was collected. A urine sample was extracted with an affinity column of anti-11-dehydro-TXB2 monoclonal antibody. Conversion of 11-dehydro-2,3-dinor-TXB3 in the urine extract into the methyl ester (ME)-11-n-propylamide (PA)-9, 12, 15-dimethylisopropylsilyl (DMIPS) ether derivative was followed by gas chromatography with selected-ion monitoring (GC/SIM) (resolution: 8000) and GC/mass spectrometry (MS). High-resolution SIM result revealed that a major component corresponded to the [M - C3H7]+ (m/z 668.4198) ion, which may be specific for the structural integrity by analogy with the corresponding 11-dehydro-TXB3 derivative. Conventional GC/MS analysis confirmed that the peak of the interest was the title compound. The mass spectrum of the 11-dehydro-2,3-dinor-TXB3 ME-PA-DMIPS ether derivative was dominated by the ions of [M - CH3]+ (m/z 696) and [M - C3H7]+ (m/z 668, base peak) and ions containing a protected 11-carboxylic acid moiety together with the unidentified additional ions which were considered to derive from urinary endogenous substances. However, the quality was sufficient for use of mass spectral identification of 11-dehydro-2,3-dinor-TXB3, the beta-oxidation product of 11-dehydro-TXB3. Characteristic fragment ions of [M - C5H9-(dimethylisopropylsilanol)n]+ (m/z 524 and 406) yielding information about the position of the incorporated double bond were prominent, the same as the corresponding ions found in the mass spectrum of the 11-dehydro-TXB3 derivative. Consequently, the fragmentation products were closely related to those of the 11-dehydro-TXB3 derivative, except for an obvious shift produced by the lack of C-2/C-3 hydrocarbon units. The results demonstrate the endogenous formation of TXA3 in humans after administration of EPA ethyl ester and excretion of 11-dehydro-2,3-dinor-TXB3 into urine as one of the enzymatic metabolites of TXB3, together with the previously reported 11-dehydro-TXB3.

Adult↗

PubMed1995

Microdetermination of 11-dehydrothromboxane B3 in human urine by gas chromatography--selected-ion monitoring using (18O2) analogue as an internal standard.

The microdetermination of 11-dehydrothromboxane B3 (11-dehydro-TXB3) in human urine is described. We prepared [18O2]11-dehydrothromboxane B3 for use as an internal standard. Samples containing an [18O2] analogue were extracted chromatographically using Sep Pak tC18 and a silica gel column. Conversion of the extracted 11-dehydro-TXB3 to 1-methyl ester-11-n-propylamide-9,12,15-dimethylisopropylsilyl ether derivative was followed by gas chromatography/selected ion monitoring (GC/SIM). Interfering substances from the urine matrix were eliminated during GC/SIM analysis using an MP-65HT column. Human urine was monitored using the ions of m/z 696.4511 (11-dehydro-TXB3), m/z 700.4597 (18O2]1l-dehydro-TXB3), m/z 698.4668 (11-dehydro-TXB3) and m/z 702.4918 ([2H4]11-dehydro-TXB2). 11-Dehydro-TXB3 and [18O2]11-dehydro-TXB3 appeared at the same retention time and were eluted 15 s after 11-dehydro-TXB2 on this capillary column. This difference in retention time was due to the double bond in the omega3 position in 11-dehydro-TXB3. A good linear response over the range of 10 pg to 10 ng/tube was demonstrated. We detected 11-dehydro-TXB3 in the range from 1.29 to 7.64 pg/mg creatinine in the human urine. In the healthy volunteers, the 11-dehydro-TXB3 level was less than 1% of that of the 11-dehydro-TXB2, but 11-dehydro-TXB3 was increased by dietary supplementation of eicosapentaenoic acid. This method can be applied to the determination of 11-dehydro-TXB3 in human urine.

Calibration↗

PubMed1994

Microdetermination of 2,3-dinor-6-ketoprostaglandin F1 alpha in human urine using gas chromatography-high-resolution selected-ion monitoring.

The microdetermination of 2,3-dinor-6-ketoprostaglandin F1 alpha (I) in human urine is described. Samples to which the [2H4]-analogue was added as an internal standard were extracted by chromatographic sample preparation using a Bond Elut C18 cartridge and a silica gel column. Conversion of the extracted I into the 1-methyl ester-6-methoxime-9,11,15-trisdimethylisopropylsilyl ether derivative was followed by gas chromatography-high-resolution selected-ion monitoring (GC-HR-SIM). Interfering substances from the urine matrix were eliminated during GC-HR-SIM analysis using a DB-1 column. A good linear response over the range 10 pg-100 ng per tube was demonstrated. Compound I could be detected in the range 26-375 pg/ml of human urine. The proposed method can be applied to the determination of I in human urine.

6-Ketoprostaglandin F1 alpha↗

PubMed1994

Analysis of 11-dehydrothromboxane B2 in human urine improved by use of gas chromatography/high-resolution selected ion monitoring with 18O2-labelled analogue as an internal standard.

Gas chromatography/high-resolution selected ion monitoring (GC/HR-SIM) for the determination of 11-dehydrothromboxane B2 (11-dehydro-TXB2) in human urine is described. Combined use of the lactone ring opening reaction and dimethylisopropylsilylation has been adopted for the analysis of 11-dehydro-TXB2, to give a new chemically stable derivative. The feasibility of using this derivative for the analysis of 11-dehydro-TXB2 in human urine has been evaluated. Following the addition of 18O2-labelled analogue, for use as an internal standard, the samples were extracted using chromatographic separation with Bond Elut C18 and silica gel. Derivatization of the extracted 11-dehydro-TXB2 was followed by GC/SIM at resolution of 5000. This method enables selective detection of 11-dehydro-TXB2 in human urine without serious interference from other endogenous substances. In 11 volunteers, the mean urinary excretions of 11-dehydro-TXB2 was 547.6 +/- 217.6 ng per day.

Chromatography, Gas↗

PubMed1994

The distribution of [11C]cocaine in normal and cocaine-sensitization mice.

[N-11C-methyl]-cocaine ([11C]cocaine), synthesized by N-methylation of norcocaine with [11C]CH3I, was used to assist in imaging the variety of local distribution by positron emission tomography (PET). The radiochemical yield and the radiochemical purity after purification of [11C]cocaine by high performance liquid chromatography (HPLC) at a sp. act. of 814 GBq/mmol were 47-58% and > 99%, respectively. The time required for synthesis including the purification was 25-30 min from the end of [11C]CH3I trapping. The physical distribution of [11C]cocaine in organ was also investigated in mice at various time after i.v. injection. The main accumulation of radioactivity occurred in the lung, kidney and brain within 1 min after the injection. In the brain, no differences in the organ were observed except the radioactivity level in each section increased for the first 5 min, since then radioactivity decreased dramatically. Furthermore, in the behavioral sensitization model of cocaine, the peak of [11C]cocaine uptake in each brain area was shown to be 5-15 min.

Animals↗

PubMed1993

Periventricular hyperintensity on magnetic resonance imaging correlated with brain ageing and atrophy.

Fifty-two patients with cerebrovascular risk factors without neurological abnormalities were reviewed with respect to periventricular hyperintensity (PVH) on T2-weighted magnetic resonance imaging (MRI); brain atrophy was also assessed by CT and T1-weighted MRI. Extensive PVH showed a stronger correlation with age-related atrophy than mild or absent PVH. The relative volume of brain affected by PVH, calculated by computer, also correlated with brain atrophy, especially ventricular enlargement. The effects of PVH on brain ageing and atrophy is discussed.

Aged↗

PubMed1993

Distribution of carbon-11 labeled methamphetamine and the effect of its chronic administration in mice.

[11C]Methamphetamine, a psychotropic agent, was synthesized by N-methylation of amphetamine with [11C]CH3 I in hopes that it could be applied in the near future to assist positron emission tomography (PET) in the imaging of its distribution in the human brain. The regional distribution of [11C]methamphetamine was investigated in the mice brain at various intervals after an intravenous (i.v.) injection. Radioactivity was higher in the hypothalamus, cortex, striatum and hippocampus. Furthermore, in chronically administered mice, the uptake of [11C]methamphetamine was higher in the striatum than those in other regions. The regional differences in the distribution of methamphetamine in the mice brain may enable the imaging of its distribution by PET using [11C]methamphetamine.

Animals↗

PubMed1992

Alterations in biodistribution of 11C-methamphetamine (MAP), 14C-MAP, and 123I-N-isopropyl-iodoamphetamine (IMP) in MAP- and cocaine-sensitized animals.

Alterations in brain distribution of 11C-MAP, 14C-MAP, and 123I-IMP in MAP- and cocaine-sensitized animals were examined to investigate the mechanism involved in increased dopaminergic transmission and behavioral sensitization. First, a significant increase in 11C-MAP radioactivity in the striatum and hypothalamus was found in the mice pretreated with MAP for 7 days. Secondly, in MAP-sensitized rats, marked increases in 14C-MAP radioactivity were found in the striatum and limbic forebrain, respectively (370% and 650%). These findings may propose a new hypothesis that subchronic MAP administration may result in a long-term change in the presynaptic cell membrane at the nerve terminal which may in turn cause an increase in both MAP and DA uptake accompanied by an increased release of DA at the synaptic cleft.

Amphetamines↗

PubMed1992

cDNA cloning of mitochondrial delta 3, delta 2-enoyl-CoA isomerase of rat liver.

A 1.08 kbp cDNA encoding rat liver mitochondrial delta 3, delta 2-enoyl-CoA isomerase (ECI) of 298 amino acid residues (Mr 32,895) was isolated from rat liver lambda gt11, lambda gt10 cDNA libraries by the combination of an immunochemical method with a rabbit-antibody against rat liver ECI and a plaque hybridization method. The deduced amino acid sequence from the cDNA indicates that ECI is synthesized with an amino-terminal extrasequence of 35 amino acid residues and processed to the mature enzyme (Mr 29,256).

Amino Acid Sequence↗

PubMed1992

Analysis of the eicosapentaenoic acid (EPA) metabolite delta 17-6-keto-PGF1 alpha in human plasma by GC/SIM using [18O] delta 17-6-keto-PGF1 alpha.

A method of the microdetermination of delta 17-6-keto-PGF1 alpha, a hydrolyzed metabolite of PGI3, is described. An authentic delta 17-6-keto-PGF1 alpha (120 mg) was prepared from eicosapentaenoic acid (EPA) incubated with homogenate of bovine aortic intima. [18O]delta 17-6-Keto-PGF1 alpha was synthesized by repeating base-catalyzed hydrolysis of methyl ester derivatives in [18O]water, to obtain an internal standard in gas chromatography/selected ion monitoring (GC/SIM) of delta 17-6-keto-PGF1 alpha. Good linear response over the range of 10 pg-10ng was demonstrated. Chromatographic conditions using a MP-65HT column presented nearly baseline separation of delta 17-6-keto-PGF1 alpha and 6-keto-PGF1 alpha. We were able to detect delta 17-6-keto-PGF1 alpha in the range from 6 to 26 pg/ml of the human plasma. The present method can be applied to the determination of delta 17-6-keto-PGF1 alpha in the human urine and plasma.

6-Ketoprostaglandin F1 alpha↗

PubMed1992

Separation and concentration of delta 17-6-keto-PGF1 alpha using monoclonal antibody to omega 3-olefin structure of trienoic prostanoids.

A monoclonal antibody against cis-3-hexen-1-ol was prepared and used to separate and/or concentrate delta 17-6-keto-prostaglandin F1 alpha (PGF1 alpha) in the human sera. cis-3-Hexen-1-ol was conjugated with the human serum albumin (HSA) according to the N-succinimidylester method and hyperimmunized to BALB/c mouse. The monoclonal antibodies were obtained from hybridoma clones established by a fusion between SP2/0-Ag14-k13 mouse myeloma cells and splenocytes of a mouse. A monoclonal antibody, named 4G9-12B, recognized the epitope characteristic for omega 3-olefin structure. The 4G9-12B antibody became more specific for delta 17-6-keto-PGF1 alpha than 6-keto-PGF1 alpha by applying inhibition ELISA using amino-residue coating plates. Using the prepared immunoaffinity columns of this antibody, delta 17-6-keto-PGF1 alpha was clearly detected in 6 pg/ml of the human blood sera by GC/MS analysis. These results suggest that the monoclonal antibody to the partial structure of trienoic prostanoid, omega 3-olefin unit, and that its immunoaffinity columns are useful in separating and concentrating delta 17-6-keto-PGF1 alpha in the human blood or urine.

6-Ketoprostaglandin F1 alpha↗

PubMed1992

[Extra-weak chemiluminescence of drugs. XIV. Quenching effects of anthraquinones on the extra-weak chemiluminescence from lipid peroxidation in rat brain homogenates].

Quenching effects of anthraquinones on the extra-weak chemiluminescence (CL) derived from lipid peroxidation in rat brain homogenates were investigated. Such anthraquinone derivatives as emodin, rhein, and alizarin quenched the CL, while anthraquinone did not quench the CL. A linear relationship between CL-quenching activity and inhibitory rate of malondialdehyde production of various compounds was demonstrated. This technique is useful for the screening method of antioxidants.

Animals↗

PubMed1991

Detection of heat-stable delta 3,delta 2-enoyl-CoA isomerase in rat liver mitochondria and peroxisomes by immunochemical study using specific antibody.

The subcellular distribution of delta 3,delta 2-enoyl-CoA isomerase [EC 5.3.3.8] and the inducing effect of clofibrate, a peroxisomal proliferator, on the enzyme activity were examined in rat liver. From the results of spectrophotometric investigation of the fractions, which were prepared by sucrose discontinuous gradient centrifugation from the light mitochondrial fraction, the isomerase activity was found in the fractions enriched in mitochondria and those enriched in peroxisomes of the control and the clofibrate treated rat livers. The anti-isomerase antibody reacted with both the mitochondrial isomerase and the peroxisomal isomerase, revealing a single band with an apparent molecular weight of 30,000. However, the isomerase was induced by clofibrate administration mainly in the mitochondrial fraction. These results suggest that delta 3,delta 2-enoyl-CoA isomerase is located in the mitochondria and the peroxisomes of the normal rat liver, and that the isomerase in the mitochondria is induced by clofibrate administration.

Animals↗

PubMed1990

Cerebral circulation and oxygen metabolism associated with subclinical periventricular hyperintensity as shown by magnetic resonance imaging.

A combined magnetic resonance imaging and positron emission tomography study was performed on 21 patients with cerebrovascular risk factors but without neurological abnormalities. Our purpose was to investigate the hypothesis that periventricular hyperintensity (PVH) reflects ischemia. Periventricular hyperintensity was evaluated with a method we devised, and cerebral circulation and oxygen metabolism were evaluated with the oxygen-15 steady-state technique. We concluded that the brain with severe periventricular hyperintensity had abnormal circulation, although oxygen metabolism was not measurably affected. The role of a compensation mechanism under conditions of decreased oxygen supply was considered.

Aged↗

PubMed1990

T1 and T2 relaxation times on gadolinium-diethylenetriaminepentaacetic acid enhanced magnetic resonance images of brain tumors.

MRI of brain tumors was performed with CPMG pulse sequence, and T1 and T2 relaxation times were measured before and after the administration of 0.1 mmol/kg Gd-DTPA. T1 and T2 became significantly shorter than before with the T1 shortening being about twice the T2's. Three types of T2 shortening were classified by the difference in the intra-tumoral transport of Gd-DTPA in the time-course study after the administration. Transportal activity of Gd-DTPA seemed to be reflected by the physiologic viability of tumor suggested by pre-contrast T2.

Adolescent↗