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Biomedical subjects

K Ikeda

Publications and source records attributed to K Ikeda.

At least 19 recordsLinked to original sources
PubMed1992

Purification and amino-acid sequence of a nerve growth factor from the venom of Vipera russelli russelli.

Nerve growth factor (NGF) was purified from the venom of Vipera russelli russelli by Sephadex G-50 gel filtration, S-Sepharose column chromatography and Blue-Sepharose CL-6B column chromatography. The purified NGF was found to be a glycoprotein, whose apparent molecular mass was estimated to be about 17.5 kDa by SDS-PAGE. The amino-acid sequence was determined by a combination of conventional methods. The V. r. russelli NGF was composed of 117 amino-acid residues with one residue, Asn-21, being N-linked glycosylated and the molecular mass of its protein portion was calculated to be 13,280 Da.

Amino Acid Sequence↗
PubMed1992

Coexistence of paired helical filaments and glial filaments in astrocytic processes within ghost tangles.

Ultrastructural examination of ghost tangles in an autopsy case of long-term Alzheimer's disease revealed, in addition to degenerate neurites containing paired helical filaments (PHF), astrocytic processes which included PHF. This finding suggests either that astrocytes in ghost tangles possess the capacity to produce PHF or that PHF are incorporated into astrocytes by endocytosis.

Actin Cytoskeleton↗
PubMed1992

Cloning and expression of the epsilon 4 subunit of the NMDA receptor channel.

The primary structure of a novel subunit of the mouse NMDA (N-methyl-D-aspartate) receptor channel, designated epsilon 4, has been revealed by cloning and sequencing the cDNA. The epsilon 4 subunit shares high amino acid sequence identity with the epsilon 1, epsilon 2 and epsilon 3 subunits of the mouse NMDA receptor channel, thus constituting the epsilon subfamily of the glutamate receptor channel. Expression from cloned cDNAs of the epsilon 4 subunit together with the zeta 1 subunit in Xenopus oocytes yields functional NMDA receptor channels. The epsilon 4/zeta 1 heteromeric channel exhibits high apparent affinities for agonists and low sensitivities to competitive antagonists. The epsilon 4 subunit is thus distinct in functional properties from the epsilon 1, epsilon 2 and epsilon 3 subunits, and contributes further diversity of the NMDA receptor channel.

Amino Acid Sequence↗
PubMed1992

Effects of phorbol ester on lower urinary tract smooth muscles in rabbits.

The contractile effects of phorbol 12,13-dibutyrate (PDBu) on rabbit urinary bladder dome and urethra were investigated using muscle bath techniques. PDBu caused concentration-dependent contractions in both tissues, and these responses were not affected by pretreatment with atropine, phentolamine, hexamethonium or indomethacin. In both tissues, 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine (H-7), a potent inhibitor of protein kinase C (PKC), inhibited PDBu-induced contractions in a concentration-dependent manner. The maximum PDBu-induced contractions in bladder dome and urethra were 33.5 +/- 3.4 and 33.3 +/- 4.1% of KCl-induced maximum contractions, respectively. In Ca(2+)-free solution or after pretreatment with nifedipine (10(-6) M), PDBu-induced contractions were reduced but not completely abolished. Although pretreatment with PDBu (10(-8) M) did not have a significant effect on the contractile responses induced by carbachol (in bladder dome) and phenylephrine (in urethra), pretreatment with H-7 (100 microM) had an inhibitory effect on carbachol- and phenylephrine-induced contractions; tonic phase contractions were more sensitive than phasic contractions. These results indicate that PDBu has significant contractile effects in rabbit bladder dome and urethra, and that the effects may be partly mediated by activation of PKC. PKC activation might also contribute to agonist-induced contractile responses in these tissues.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Increased plasma concentrations of aspartate, glutamate and glycine in Parkinson's disease.

We measured fasting plasma amino acids in 20 patients with Parkinson's disease (PD) and 20 controls matched for age and sex. PD patients had significant elevations in plasma levels of aspartate, glutamate and glycine. The levels of other amino acids were not significantly different from those found in controls. No correlation was noted between PD severity and the degree of abnormality of plasma amino acids. We conclude that excitatory amino acids may be altered in patients with PD, and raise the possibility that neuroexcitotoxic mechanisms may be involved in the neurodegeneration of PD.

Aged↗
PubMed1992

[MR imaging during arterio-portography (MR-AP) in the detection of hepatic cancer].

Magnetic resonance imaging during arterio-portography (MR-AP) was performed in 2 patients of hepatic cancer. Low dose of meglumine gadopentetate (4 ml of a 0.5 mmol/L solution) was injected into a superior mesenteric artery during acquisition of a Turbo-FLASH sequence. An increase in liver to lesion contrast was obtained with MR-AP and it is also useful in the late phase to distinguish a flow defect lesion due to portal obstruction from the tumor.

Gadolinium DTPA↗
PubMed1992

Glial fibrillary tangles with straight tubules in the brains of patients with progressive supranuclear palsy.

A recent report has described the appearance of silver positive, tau-immunoreactive astrocytes in the brains of patients with progressive supranuclear palsy (PSP) (Neurosci. Lett., 135 (1992) 99-102). In this study we confirmed this finding in two cases of PSP by using Bodian silver staining and immunohistochemistry with antibody to human tau protein. By electron microscopy we demonstrated that fibrillary masses present in these unique astrocytes were made up of straight tubules that were indistinguishable from those of neurofibrillary tangles of PSP. The term 'glial fibrillary tangle' was proposed for these structures.

Aged↗
PubMed1992

The T-loop region of animal mitochondrial tRNA(Ser)(AGY) is a main recognition site for homologous seryl-tRNA synthetase.

Recognition sites of bovine mitochondrial serine tRNA specific for condons AGY [tRNA(Ser) (AGY)] by the cognate mitochondrial seryl-tRNA synthetase were studied using a range of tRNA(Ser)(AGY) variants which were obtained by the in vitro transcription of synthetic tRNA genes with T7 RNA polymerase. Base replacements in the anticodon and discriminator sites did not affect serine acceptance. However, deletion and/or replacement in the T-loop region completely deprived the variants of their charging activities. Point mutation experiments in this region also showed that the adenosine residue in the middle of the T-loop (position 58), which is involved in tertiary interaction between the T-loop and the truncated D-arm [de Bruijn and Klug, 1983] played a significant role in the recognition process by the synthetase.

Animals↗
PubMed1992

[Liver abscess formation after treatment of liver cancer by arterial injection using adriamycin/mitomycin C oil suspension (ADMOS)].

Of 210 patients with hepatocellular carcinoma (n = 135), metastatic liver cancer (n = 71) and cholangiocarcinoma (n = 4) who underwent intra-arterial infusion of adriamycin and/or mitomycin C oil suspension (ADMOS) and cisplatin, and both regimens, pyogenic liver abscess occurred in seven (3.3%). The percentages of abscess formation in the respective types of liver cancer were 0.8, 7.0 and 25%. These differences among the three types of liver cancer were attributed to the volume of the tumor vascular beds to be embolized, which might determine the relative amount or regional Lipiodol retention in the tumor and normal liver tissue. Four of seven patients with hepatic abscess had received the intra-arterial infusion of ADMOS, and their angiographic findings showed sequential decreases in the vascular beds of the tumor in comparison with those of previous infusion procedures; all had hypovascular liver tumors angiographically. We have never experienced this complication in other treatments such as embolization of the hepatic arteries and intra-arterial infusion of water-soluble anticancer drugs alone. These results suggest that the most important factor leading to abscess formation is the ischemic destruction of the intrahepatic ducts secondary to occlusion of the peribiliary arterial plexus by Lipiodol and/or the direct effects of anticancer drugs on these vessels. To avoid this complication, the volume of Lipiodol used for intraarterial infusion therapy should be carefully determined, especially when the patient has hypovascular tumors of the liver and a history of multiple previous intraarterial infusion procedures of anticancer drug. The use of ADMOS should be avoided in patients with hypovascular tumors of the liver such as secondary deposits and cholangiocarcinoma.

Adenoma, Bile Duct↗
PubMed1992

Apolipoprotein B immunoreactivity in senile plaque and vascular amyloids and neurofibrillary tangles in the brains of patients with Alzheimer's disease.

Based upon our previous finding of the association of apolipoprotein E (apoE) immunoreactivity with cerebral amyloids and neurofibrillary tangles (NFTs), we examined immunohistochemically whether this is also the case for apolipoprotein B (apoB). Polyclonal antibody to apoB immunosustained senile plaque amyloid, vascular amyloid, subpial amyloid deposits and intracellular NFTs in formalin-fixed, paraffin-embedded brain sections from patients with Alzheimer disease. Hydrated autoclave pretreatment of the sections enhanced the staining of plaque amyloid. The results may suggest a role of apoB in amyloid and NFT formation.

Aged↗
PubMed1992

Transcriptional activation of c-fos and c-jun protooncogenes by serum growth factors in osteoblast-like MC3T3-E1 cells.

The present study was undertaken to clarify the relationship between c-fos and c-jun protooncogene expression and the differentiation and/or proliferation of osteoblasts, using osteoblast-like MC3T3-E1 (E1) cells. c-fos mRNA was barely detectable, whereas c-jun mRNA was constitutively expressed in E1 cells after serum deprivation for 24-72 h. When serum was added, a rapid and transient induction of c-fos and c-jun mRNAs was observed. The c-fos and c-jun mRNAs reached peak levels at 30 minutes, with a rapid disappearance of c-fos mRNA within 3 h and a much slower decrease in c-jun mRNA. The addition of serum together with cycloheximide, an inhibitor of protein synthesis, resulted in the superinduction of both c-fos and c-jun mRNAs. Among various growth factors, PDGF, EGF, and bFGF mimicked the serum effect, whereas IGF-I and TGF-beta failed to induce c-fos and c-jun mRNA. The effects of PDGF, EGF, and bFGF were completely abolished by pretreatment with actinomycin D, an inhibitor of RNA synthesis, suggesting a transcriptional mechanism. Nuclear runoff experiments showed that the transcription rate of c-fos and c-jun protooncogenes was increased by serum and growth factors. The effects of PDGF, EGF, and bFGF were inhibited by H-7 or staurosporine, inhibitors of protein kinase C (PKC), but not by HA1004 with a much weaker inhibitory activity, suggesting the involvement of PKC for the activation of the protooncogenes.(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

A multicenter comparison of nicorandil and diltiazem on serum lipid, apolipoprotein, and lipoprotein levels in patients with ischemic heart disease.

The effects of nicorandil and diltiazem on serum lipid, apolipoprotein, and lipoprotein levels in 37 patients with ischemic heart disease were examined in a randomized, multicenter study. Nicorandil (n = 20, 10-40 mg/day, b.i.d.) and diltiazem (n = 17, 60-240 mg/day, b.i.d.) were administered for 12 weeks. Both nicorandil and diltiazem administration showed an effective antianginal effect. Diltiazem administration showed a significant hypotensive action. There were no significant changes in serum lipids, apolipoproteins, and lipoproteins for both nicorandil and diltiazem. There were no significant changes in body weight, uric acid, and fasting blood sugar levels during the test period for both drugs. These data show that nicorandil, like diltiazem, does not have any adverse effects on lipid metabolism and that it is a favorable drug to use as an agent for treating arteriosclerotic heart disease.

Aged↗
PubMed1992

Evidence that neurofibrillary tangles undergo glial modification.

Ghost tangles, neurofibrillary tangles (NFTs) emerging into extracellular space, appear to be subjected to some microglial association in addition to an invasion of astrocytic processes. Our findings lead us to speculate that the NFTs undergo structural and immunocytochemical modification. Electron microscopic observation of the NFTs in the vascular region indicated either the discharge of NFTs into the vessel or formation of NFTs in the astrocytic end-foot.

Aged↗
PubMed1992

Comparison of the anticancer effect of ADMOS alone and ADMOS with CDDP in the treatment of hepatocellular carcinoma by intra-arterial injection.

A total of 135 patients with hepatocellular carcinoma (HCC) were treated by intra-arterial injection of an Adriamycin/mitomycin C oil (lipiodol) suspension (ADMOS) alone or of ADMOS plus cis-diammine-dichloroplatinum (CDDP). In all, 59 patients were treated with ADMOS alone and 76 were treated with ADMOS plus CDDP. A reduction of more than 25% in the tumor size was obtained in 13 of 38 (34%) evaluable patients in the former group and in 39 of 76 (51%) evaluable patients in the latter group. Serum alpha-fetoprotein (AFP) levels decreased by more than 50% in 10 of 17 (59%) and 23 of 33 (70%) patients in the respective groups whose pretreatment AFP level was estimated to be over 200 ng/ml. Overall, the 1-year survival value was 68% and the 2-year value was 41% as determined by the Kaplan-Meier method. No statistically significant difference in survival was observed between the two groups. The initial tumor response correlated with the survival value. No severe complication was encountered except for one case of liver abscess formation. No serious change in the laboratory data was observed following treatment with these regimens. Although the tumor response was significantly better in patients treated with ADMOS combined with CDDP injection than in those treated with ADMOS alone (P < 0.05), no significant difference in survival was found between the two groups.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Alanine aminotransferase and HCV-RNA responses following interferon therapy of HCV-RNA positive chronic hepatitis.

Interferon (IFN) has been shown to be effective for chronic hepatitis C. This study investigated changes of alanine aminotransferase (ALT) and HCV-RNA in chronic hepatitis C patients treated with alpha-IFN. IFN was given to 73 patients with HCV-RNA positive chronic hepatitis C. The pattern of changes in ALT activity after IFN administration was classified into five types. Type 1 was characterized by normalization of ALT (< or = 25 K.U) during IFN administration and sustained normalization after the IFN therapy. Type 2 involved a rebound of ALT after termination of IFN therapy and subsequent normalization. Type 3 had no ALT normalization during IFN administration, with normalization after the completion of the therapy. Type 4 involved transient normalization of ALT level during IFN therapy, with a subsequent reversion to abnormal levels after the termination of IFN therapy. Type 5 showed sustained abnormally high levels of ALT activity both during and after treatment. Twenty four patients (32.9%) had sustained normalization ALT (< or = 25 K.U) after the termination of IFN treatment. The HCV-RNA negative rate at 6 months after IFN therapy in patients with sustained normalization of ALT was 87.5% (21/24).

Adult↗
PubMed1992

TRH analogue, TA-0910 (3-methyl-(s)-5,6-dihydroorotyl-L-histidyl-L-prolinamide) enhances neurite outgrowth in rat embryo ventral spinal cord in vitro.

We have studied effects of TRH analogue, TA-0910 (3-methyl-(s)-5,6-dihydroorotyl-L-histidyl-L-prolinamide) (from Tanabe, Osaka, Japan) on explanted ventral and dorsal spinal cord cultures from 13- and 14-day-old rat embryos. TA-0910-treated cultures had significantly increased neurite outgrowth with cultures of ventral spinal cord, but not with cultures of dorsal spinal cord. The effect was dose-dependent. A possible role for TRH in amyotrophic lateral sclerosis remains to be defined.

Animals↗
PubMed1992

Postoperative central conduction time and cerebral blood flow in patients with aneurysmal subarachnoid hemorrhage: relationship with prognosis and ischemic conditions.

Cerebral blood flow (CBF) and somatosensory evoked potential (SEP) were monitored periodically on 32 patients who underwent aneurysm clipping within 3 days after subarachnoid hemorrhage (SAH). From the SEP data, central conduction time (CCT) was obtained, and CCT fluctuations were categorized into three types. Patients with CCT prolongation over 7.5 ms within 10 days after SAH tended to have poor recovery of CBF and unfavorable outcome. Therefore, periodical monitoring of CCT was considered as a useful indicator for predicting prognosis and post-SAH changes of cerebral blood flow.

Adult↗