Biomedical subjects

T Yoshii

Publications and source records attributed to T Yoshii.

At least 37 records · Page 2Linked to original sources

PubMed1999

[Superiority of intrafascicular neurography over conventional nerve conduction studies in evaluating axonal degeneration].

We investigated conventional motor and sensory nerve conduction studies (MCS & SCS) with regard to the sensitivity in detecting axonopathies. Twelve patients with axonal type of polyneuropathy, 2 vincristin neuropathy and 10 cisplatin neuropathy, were examined by MCS & SCS. Their data were compared with those by intrafascicular microneurography (MNG) of the median nerve. Nerve conduction velocities were within normal limits or slightly reduced to 87-99% of the normal. Amplitude of compound muscle action potential (CMAP) by MCS decreased to 4 or 5 mV in vincristin neuropathy, though cisplatin neuropathy presented normal amplitude. Amplitude of sensory nerve action potential (SNAP) by SCS was undetected in one median nerve and in three sural nerves. While, compound nerve action potential (CNAP) by MNG was all recorded, and presented the amplitude value of below 150 microV in seven patients. The waveform was normal or mild neuropathic pattern. No patients presented normal CNAP amplitude and reduced SNAP amplitude. But there were three patients who had normal SNAP amplitude and reduced CNAP amplitude. In SCS we could recognize abnormal only after CNAP amplitude by MNG dropped to below 100 microV. Cisplatin neuropathy demonstrates reduction of CNAP or SNAP amplitude, and vincristin neuropathy further presents reduction of CMAP amplitude. Evaluation of axonopathy is best achieved by nerve action potential amplitude. Conventional surface electrode methods are available for this purpose, but MNG is more sensitive and is capable of quantitative analysis even in severely damaged nerves.

Action Potentials↗

PubMed1999

[Effects of interelectrode separation in sensory nerve conduction studies].

Sensory nerve action potentials (SNAPs) obtained by conventional sensory nerve conduction studies are greatly influenced by the distance between exploring and reference electrodes. Changes in SNAPs were investigated in 12 healthy median nerves using the orthodromic and antidromic sensory nerve conduction studies with 1-cm, 2-cm, 3-cm, 4-cm, and 5-cm of interelectrode distances. Peak-to-peak (orthodromic) or baseline-to-peak (antidromic) amplitudes and durations between the positive peaks were measured and each value was expressed as a ratio to the recording of 1-cm of interelectrode distance. SNAPs with maximum amplitude were obtained by more than 3-cm of interelectrode distance. Duration of SNAP was increased by an increase of interelectrode distance. Change in amplitude along with the interelectrode distance was larger in the orthodromic method than in the antidromic method. Contrariwise, change in duration was larger in the antidromic method. SNAPs with long duration had a gently sloping configuration, and each peak tended to be indistinct. So, 3-cm of active and reference interelectrode separation should be recommended in performing sensory nerve conduction studies between wrist and finger, because maximum amplitude and clear visualization of peaks are available.

Action Potentials↗

PubMed1999

[The structural polymorphism in D8S580-STR region].

The STR structure of the D8S580 locus was analyzed by the base sequencing technique. Alleles were collected separately by urea denaturing polyacrylamide gel electrophoresis of the PCR amplification product, followed by cutting of the target DNA band from the gel, and reamplification. As a result, this locus was shown to have a complex STR structure consisting of four types of repeat units, i.e. GGAA (II), GAAA (III), GAAAA (IV), and GCAA (V). Of 53 unrelated Japanese individuals, 51 were heterozygous, and the most frequent allele was type IV 8-II 7 III 6 III 3 (16%). Forty-four alleles with distinct structures appeared once the samples tested. As 57 different alleles were detected in this study, this region is considered to be one of the locus that have a high degree of repetitive structural polymorphism and therefore useful in forensic science.

Humans↗

PubMed1997

Attenuation of cryogenic induced brain oedema by arginine vasopressin release inhibitor RU51599.

Centrally released arginine vasopressin (AVP) has been implicated in the regulation of the brain water content and is elevated in the cerebrospinal fluid of patients with ischaemic and traumatic brain injuries. The protective effect of RU51599, which is a selective kappa opioid agonist as an AVP release inhibitor, on brain oedema was examined. Male Wistar rats, weighing 300 to 400 g each, were used. The cortical cryogenic injury was produced by application of a previously prepared metal probe cooled with dry ice to the dura of the right patietal region. Animals were separated into three groups. Group 1: sham operated rats without lesion production. Group 2: saline-treated rats with lesion production. Group 3: RU51599-treated rats with lesion production. In Group 3, rats were treated with RU51599 (0.1-3 mg/kg) at 30 minutes before lesion production, 1 hour, 2 hours, and 4 hours after lesion production. After 6 hours, animals were decapitated and brain water contents were measured using the dry-wet weight method. The extent of blood brain barrier (BBB) disruption was determined by assessment of Evans blue uptake based on extraction from tissue using dimethylformamide. The primary injured infarcted area was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Sodium and potassium contents in serum and brain tissue were measured using atomic absorption spectrophotometry. The antagonism of naloxone against protective effects of RU51599 on cryogenic induced brain oedema and on antinociceptive effects in acetic-acid treated animals was examined. Statistical analysis was performed using Dunnett-test and U-test following Kruskal-Wallis test. RU51599 significantly reduced the brain water contents on the injured side and the contralateral non-injured side (p < 0.01) after 4 administration of 1 and 3 mg/kg. RU51599 neither significantly inhibited BBB disruption nor reduced the primary injured infarcted area. RU51559 significantly increased brain sodium and potassium contents in the injured brain and also increased serum sodium levels (p < 0.01). Naloxone antagonized the anti-oedema effects and anti-nociceptive effects of RU51599. These findings indicate that the AVP release inhibitor, RU51599 possibly mediated by opioid receptors, has a potential protective effect on cryogenic-induced brain oedema and that centrally released AVP plays an important role in the progression of vasogenic brain oedema.

Animals↗

PubMed1997

[Structural polymorphism of ACTBP2 STR region].

We investigated structural polymorphisms of the ACTBP2-STR region by sequence analysis instead of using PCR-amplified fragment length polymorphisms. A gel spot extraction reamplification method using 2% agarose gel was effective for preparing the individual alleles from zygotes with a length difference of more than 16bp. In a survey of polymorphisms in 116 unrelated Japanese subjects, alleles from 73 zygotes were prepared by this method. The STR structure of the allele was determined from the forward sequence image. The allele designation was made according to the number of the repeated AAAG tetranucleotide and also the position of the inserted AA or AG dinucleotide. Forty-three zygotes impossible to separate were first sequenced in a forward direction. Among them, 28 zygotes were typed directly by analysing the sequence image which exhibited a peculiar overlap of two sequences. For the remaining 15 zygotes, it was possible to type by analysing the forward and reverse sequence images together. This investigation revealed the presence of 79 kinds of alleles in 116 zygotes of ACTBP2. The most frequent allele was type 19, which accounted for 9.5% although this was still a small portion. Genotypes 19/20, 19/21, 18/21, 18/10AA12, 19/13AA11 and 20/13AA15 were detected from two subjects, respectively, and others including the type 19 homozygyote were unique.

Alleles↗

PubMed1997

[Percutaneous transcatheter thermotherapy (PTCT): use of hotwire for local tumor control].

We developed a Hotwire for use in percutaneous transcatheter thermotherapy (PTCT) for local tumor control. The Hotwire has a temperature sensor and a heater, and is inserted into the hepatic artery through a Y-connector and an angiocatheter. It can then warm fluid from the Y-connector to 45 degrees C under electorical control PTCT was performed on liver tumors using 4 mg of MMC and 10 mg Epirubicin. The antitumor effects and indications for PTCT were investigated in patients with unresectable liver tumors, including 3 patients who had hepatocellular carcinoma (HCC) with intraportal invasion and collateral vessels, one patient with liver metastasis of rectal cancer, and two gastric cancer patients. In all patients, tumor marker levels decreased (PIVKA-II; 8.5-->0.9, 2.9-->0.9, AFP; 1154-->753, CEA; 300-->226, TPA; 6319-->4227, 3312-->943), and CRP levels were markedly elevated with tumor fever. The only adverse reaction to PTCT was nausea and vomiting in one female patient. We repeated PTCT 6 times for giant HCC, and performance status was improved (2-->0). In conclusion, PTCT using the Hotwire is useful for treating hypervascular tumors limited to the liver, especially HCC with intraportal invasion and collateral vessels.

Aged↗

PubMed1997

[Effect of arginine vasopressin (AVP) inhibitor in the inhibition of the peritumoral edema].

We investigated the effect of RU599 Arginine Vasopressin (AVP) inhibitor on peritumoral edema of Wistar rats implanted with C6 glioma. C6 glioma was implanted into the right caudoputamen of 3 week-old rat's brain. Five weeks after the implantation, the changes of the brain water contents were measured by the dry-weight method. RU599 (1 mg/ml/kg body weight) was administered into Wistar rats via the tail vein every one hour (total 4 times), and the same dose of saline was used as control. Rats were sacrificed 1 hour after the last administration, and the brain of each rat was divided into 3 parts such as the anterior part without a tumor, the middle part with a tumor and the posterior part without a tumor. After that each part was separated into the right and left parts. The tumor was removed from the brain. The water contents of the brain were increased in the area around the tumor and the contralateral cerebral hemisphere excluding the anterior part. RU599 could reduce the increased water contents significantly in all areas except in the tumor itself and the area surrounding the tumor. Tumor-origin brain edema includes not only localized one but also diffuse one in the brain, and this study suggests RU599 has an effect of inhibiting the diffuse brain edema.

Animals↗

PubMed1996

Activation of ventral tegmental GABAB receptors inhibits morphine-induced place preference in rats.

The effect of microinjection of a GABAB receptor agonist, baclofen, into the ventral tegmental area on the rewarding effect of morphine was investigated using the conditioned place preference paradigm in rats. Morphine (1-8 mg/kg, s.c.) caused a dose-related place preference for the drug-associated place. In contrast, microinjection of baclofen (0.1-1 nmol/side) into the ventral tegmental area did not produce a significant preference for either compartment of the test box. Pretreatment with baclofen (0.1-1 nmol/side) into the ventral tegmental area dose dependently suppressed the morphine (8 mg/kg, s.c)-induced place preference. This suppression of the morphine (8 mg/kg, s.c.)-induced place preference by baclofen (1 nmol/side), but not with the GABAA receptor antagonist bicuculline (1 nmol/side). The present results suggest that a decrease in GABAB neurotransmission in the ventral tegmental area, which may be produced via inhibition of a tonic GABAergic input by morphine, may be involved in the expression of the rewarding effect of morphine.

Animals↗

PubMed1996

Involvement of GABA(B) receptor systems in action of antidepressants: baclofen but not bicuculline attenuates the effects of antidepressants on the forced swim test in rats.

Involvement of GABAergic systems in action of antidepressants was examined in the forced swim test in rats. Rats were forced to swim in a cylinder for 15 min on day 1 and for 5 min on day 2. Desipramine, mianserin and buspirone, administered after the 15-min swim session on day 1 and before the 5-min swim test on day 2, dose-dependently decreased the duration of immobility in the swim test on day 2. Baclofen attenuated the decreased duration of immobility induced by desipramine, mianserin and buspirone in the swim test, although baclofen did not affect the duration of immobility when it was injected alone. Muscimol dose-dependently decreased the duration of immobility in the swim test on day 2. Bicuculline antagonized the decreased duration of immobility induced by muscimol. However, bicuculline failed to antagonize the decreased duration of immobility induced by desipramine, mianserin and buspirone. These results suggest that GABA(B) but not GABA(A) receptor systems may be involved in action of antidepressants.

Animals↗

PubMed1996

Cytotoxic xanthones from Garcinia hanburyi.

Eleven novel cytotoxic xanthones, gambogin, morellin dimethyl acetal, isomoreollin B, moreollic acid, gambogenic acid, gambogenin, isogambogenin, desoxygambogenin, gambogenin dimethyl acetal, gambogellic acid and hanburin were isolated together with four known xanthones, gambogic acid, isomorellin, morellic acid and desoxymorellin, from the dry latex of Garcinia hanburyi. The structures were elucidated by a detailed spectroscopic analysis.

Cell Line↗

PubMed1996

Antiviral activity of lignans and their glycosides from Justicia procumbens.

Ten antiviral lignans, seven known (justicidins A, B, C and D, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate) and three new compounds, justicidinosides A (justicidin C 6'-O-glucoside), B (justicidin A 6'-O-glucoside) and C (justicidin B 6'-O-glucoside), were isolated from a methanolic extract of the aerial parts of Justicia procumbens var. leucantha. Justicidins A and B, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate showed strong antiviral activity (the MIC were less than 0.25 microgram ml-1, respectively) against vesicular stomatitis virus and low cytotoxicity (the MTC were larger than 31 micrograms ml-1, respectively) against cultured rabbit lung cells (RL-33).

Animals↗

PubMed1995

Involvement of cholinergic systems in the deficit of place learning in Morris water maze task induced by baclofen in rats.

Effects of oxotremorine on the deficit of place learning in the Morris water maze task induced by baclofen and scopolamine were examined to determine the involvement of brain cholinergic systems in the deficit of learning induced by baclofen. Rats were given 4 training trials per day with the submerged platform at a fixed location in the maze for 4 days. On day 4, rats were required to swim in the pool without the platform after the 4th training trial (probe test). Baclofen as well as scopolamine dose-dependently increased the escape latency in the training trials. In the probe test, baclofen as well as scopolamine dose-dependently reduced the duration in the quadrant where the platform had been originally located. Increased latency in the training trials and reduced duration in the probe test induced by scopolamine were dose-dependently attenuated by oxotremorine. Increased latency and reduced duration in the baclofen-treated rats were improved by oxotremorine as well as 2-hydroxysaclofen. Baclofen but not scopolamine induced motor incoordination in the rotarod test. Oxotremorine failed to improve motor incoordination induced by baclofen. These results suggest that cholinergic systems may be involved in the deficit of place learning induced by baclofen, and that the ameliorative effects of oxotremorine may not be due to improvement of motor incoordination.

Animals↗

PubMed1995

Muscimol induces state-dependent learning in Morris water maze task in rats.

Effects of muscimol on the place learning in Morris water maze task were investigated in rats. Rats were given 4 training trials per day with the submerged platform at a fixed location in the maze for 4 days. On day 4, rats were required to swim in the pool without the platform after 4 training trials (probe test). Compared to the saline-treated rats, the rats treated with muscimol on day 1-4 showed no modifications of place learning in the training trials and the probe test. However, in the rats treated with muscimol on day 1-3 and treated with saline on day 4, there was increased latency to reach the platform and reduced duration in the quadrant where the platform had been located on day 4. The increased latency in the training trials and reduced duration in the probe test on day 4 was blocked by bicuculline, when bicuculline and muscimol were co-administered on day 1-3, and saline was injected on day 4. Moreover, in the rats treated with muscimol on day 1-3, co-administration of bicuculline and muscimol on day 4 blocked place learning: increased latency in the training trials and reduced duration in the probe test was observed. These results suggest that muscimol induces state-dependent learning (SDL) in Morris water maze task, and that muscimol-induced SDL is mediated by GABAA receptors.

Animals↗

PubMed1995

[Sequence polymorphism of mitochondrial DNA and its forensic application].

We have investigated polymorphism of mitochondrial (mt) DNAs in the Japanese population. In order to compare 288-bp sequences (nucleotide positions 16,111 to 16,398) in the noncoding region, a 452-bp segment elongated by 82 bp at both sides of the target was amplified by PCR and analyzed directly by Taq cycle sequencing with FITC-labelled primers. A survey of 100 Japanese individuals revealed the existence of 66 types of mtDNAs. Among them, 10 types including two frequent types were shared by more than one individual. During this investigation, it was found that 19 types (from 25 individuals) possessed a common nucleotide replacement of T by C at position 16,189, by which a "C-continuous stretch" was formed, and that clear reading of their sequences was restricted in the region lying ahead of the C stretch on either forward or reverse sequencing. Cloning analysis of PCR product possessing the C stretch demonstrated that the length of the C stretch was heterogeneous. Consequently, we propose the following rules for mtDNA sequencing and its forensic application: 1) the replacement of T by C at position 16,189 is acceptable as a variation factor. 2) The number of Cs in the C stretch is tentatively fixed at 10.

Asian People↗

PubMed1995

Bone mineral density changes in distracted callus stimulated by pulsed direct electrical current.

To evaluate the effect of application of pulsed direct current electrical stimulation to callus tissue, a 1-cm bone-lengthening model using an external lengthener was applied to rabbit tibia. Twenty-microampere pulsed direct current was applied 12 hours daily from the day of osteotomy until 40 days after the completion of lengthening. The area, bone mineral content, and bone mineral density of the distracted callus and of the proximal and distal segments of the tibia were evaluated using dual-energy xray absorptiometry. The absolute and relative values of bone mineral density of the electrically stimulated callus were significantly increased as compared with those in the control group. Pulsed direct current electrical stimulation may be indicated in bone lengthening to stimulate the poorly mineralized callus, and may shorten the overall time course of leg lengthening.

Absorptiometry, Photon↗

PubMed1995

[HLA-DQB2 genotypes analyzed by PCR/SSCP method].

When the PCR products amplified by the primers prepared at the 11th HLA Workshop (DQBAMP-A, DQBAMP-B) were analyzed directly by the SSCP method, one or two pairs of characteristic bands were detected other than those attributed to DQB1, and a total of three kind of paired bands were detected. To confirm that these bands were allelic genes of DQB2, the corresponding bands were isolated by cloning, and their base sequences were determined. The base sequence of one of them was in agreement with that of DX beta, which has already been described, and the characteristic 3-base defect was noted by comparison with the base sequence of DQB1. The same 3-base defect was noted also in the other two kinds. One-base substitution was present in each of the three kinds of base sequence, and they were confirmed to be allelic genes of DQB2. In DQB1 typing by the PCR/SSCP method of Carrington et al., treatment with the restriction enzyme Alu 1 is needed to eliminate DQB2. However, the use of this enzyme was theoretically demonstrated to be inappropriate, because it degraded the DQB1*0401 gene.

Base Sequence↗

PubMed1994

Direct proof of nitric oxide formation from a nitrovasodilator metabolised by erythrocytes.

When 15N-isosorbide dinitrate was injected into rats, the venous blood showed a 2-line hyperfine structure in the electron spin resonance (ESR) spectra of NO hemoglobin (HbNO), proving generation of 15N-NO. When human blood was mixed with 15N-isosorbide dinitrate anaerobically, ESR spectra showed initially 14N-HbNO, which was then overwhelmed with the increased 15N-HbNO. With deoxygenation of the blood of another 4 male donors without addition of isosorbide dinitrate, two showed 14N-HbNO, but others did not, suggesting varied amount of NO-precursers, nitrosothiols, in human blood. Neither N-ethylmaleimide nor S-hexylglutathione, a glutathione-S-transferase inhibitor, inhibited the formation of UbNO in the hemolysate mixed anaerobically with isosorbide dinitrite.

Adult↗

PubMed1994

Lengthened callus activated by axial shortening. Histological and cytomorphometrical analysis.

The tibiae of rabbits were lengthened by 10 mm in 2 weeks, then approximately one half of the limbs were shortened by 2 mm in 3 days, and left for 3 days. Histological and cytomorphometrical findings of the calluses in both groups were compared. In the shortened callus, marked histologic changes were observed in the central mesenchymal cell layer where the number of the osteoblasts increased 4 fold, and massive primitive fiber bone formation took place. Cartilaginous tissue did not seem to respond to the axial shortening stress.

Animals↗