Biomedical subjects

Y Nakajima

Publications and source records attributed to Y Nakajima.

At least 91 records · Page 5Linked to original sources

PubMed2001

Repeat liver resection for hepatocellular carcinoma.

BACKGROUND: Although hepatectomy has been accepted as a therapeutic option for the primary tumor of hepatocellular carcinoma (HCC), what role the second liver resection will play in the clinical care of patients with intrahepatic recurrence of HCC after the initial resection has not been well evaluated. STUDY DESIGN: In a retrospective review of the 6-year period between January 1991 and December 1996, records were examined of 94 patients who underwent curative liver resection for HCC. Of these, 57 patients had isolated recurrent disease to the liver; 12 of the 57 patients underwent repeat surgical resection and 45 patients received nonsurgical ablative therapy. Clinical data for these patients were reviewed for operative morbidity and mortality, survival, disease-free survival, and pattern of failure. RESULTS: There were no perioperative deaths during repeat liver resections for recurrent HCC. Operative morbidity in the second resection was comparable to the initial resection. The disease-free survival rate after the second hepatectomy was 31% at 2 years, significantly lower than that after initial hepatectomy (62%) (p = 0.009). The overall survival rate after the second hepatectomy was 90% at 2 years, in contrast to 70% after nonsurgical ablative treatment for recurrent HCC (p = 0.253). CONCLUSIONS: Although the second liver resection for recurrent HCC can be performed safely and may improve survival, the disease-free survival rate after such resection therapy is low. This likelihood of further recurrences encourages studies for the selection of patients who may benefit from repeat liver resection.

Aged↗

PubMed2001

Plasma triglyceride-rich lipoprotein remnants as a risk factor of 'Pokkuri disease'.

In our recent report, it remained unclear whether or not triglyceride-rich lipoprotein remnants (RLP) were associated with the risk of sudden coronary death in younger cases without coronary atherosclerosis that were detected in about 10% of all sudden coronary death cases in Japan. These cases were categorized as 'origin unknown, but suspected to be due to coronary spasm', the so called 'pokkuri disease' in Japan. The present study population consisted of 108 sudden death cases without coronary atherosclerosis [(pokkuri disease n=57) and non-cardiac sudden death (control n=51)] aged 20-69 years from Kanagawa prefecture in Japan. All individuals had died suddenly and unexpectedly, most had no significant history of medical conditions including cardiac symptoms and had not taken medications prior to death according to their medical records. All the autopsies were performed within 12 h after death. Plasma total cholesterol (TC), triglycerides (TG), phospholipids, RLP-C and RLP-TG, VLDL-C, LDL-C, HDL-C, apolipoproteins A-I, A-II, B, C-II, C-III, E, Lp (a) and homocysteine were measured in postmortem plasma samples. The TG-rich lipoprotein remnants measured as RLP-C and RLP-TG were significantly higher in pokkuri disease compared with controls both in fasting and postprandial states (P<0.05 and P<0.001), indicating that RLP-C and RLP-TG were the most significant risk factor in pokkuri disease among the parameters tested in this study. In conclusion the TG level in RLP (RLP-TG) appeared to be strongly associated with the risk of sudden death in the absence of coronary atherosclerosis (pokkuri disease).

Journal Article↗

PubMed2001

Involvement of mitochondrial permeability transition and caspase-9 activation in dimethyl sulfoxide-induced apoptosis of EL-4 lymphoma cells.

We observed that dimethyl sulfoxide (DMSO) induced apoptotic changes in the EL-4 murine lymphoma cell line and that effect was dependent on the concentration and time period. Incubating cells over a period of 18 h, 2.5% DMSO was found to induce sub-G1 peak in DNA histograms analyzed by flowcytometer and nucleosomal ladder formation in DNA gel electrophoresis. We also found down-regulation of Bcl-2, collapse of mitochondrial membrane potential (delta psi m) occurred following DMSO treatment, and release of cytochrome c from the mitochondria to cytosol. These observations suggest that DMSO converted its pro-apoptotic signal at the mitochondria. In the involvement of caspases, caspase-9 and -3, but not caspase-8, were found to be activated responding to DMSO treatment. Inhibitory experiments demonstrated that caspase cascade of mitochondrial apoptotic pathway was indispensable for DMSO-induced apoptosis. In the caspase cascade, caspase-9 was an upstream initiator and its primary signal could be transduced and amplified by caspase-3, -6 and -7. Kinetic study of these data showed mitochondrial dysfunction and caspase activation occurred at 12 h and apoptotic change of nuclear DNA at 18 h, providing another support for the transduction of DMSO pro-apoptotic signal via the mitochondrial pathway.

Animals↗

PubMed2001

A novel orfB-related gene of carrot mitochondrial genomes that is associated with homeotic cytoplasmic male sterility (CMS).

Three types of orfB-related genes, orfB-F1, orfB-F2 and orfB-CMS, were found in carrot mitochondrial genomes. OrfB-F1 has a structure similar to the reported orfB gene in sunflower, and orfB-F2 is a novel chimeric gene with about 200 bp of unknown sequence at the 3' end of the orfB-related sequence. All fertile plants examined contained either orfB-F1 or orfB-F2. OrfB-CMS is also a novel chimeric orfB-related gene with an additional 170 bp of unknown sequence at the 3' end. Fifteen carrot lines including petaloid CMS were examined by PCR analysis and all petaloid CMS plants were found to contain the orfB-CMS gene. The orfB-F2 and orfB-CMS genes coexist in three lines, and these lines exhibit a CMS phenotype, suggesting that the CMS phenotype is associated with orfB-CMS and is independent of the presence of orfB-F2. Interestingly, differences in predicted amino acid sequence between orfB-CMS and orfB-F2 were very limited and restricted to the carboxy-terminal region of the protein. The orfB-related genes were transcribed as expected from their DNA structures, but orfB-CMS protein accumulated only in floral organs of the CMS lines. Four RNA editing sites were common to orfB-CMS and orfB-F2, and C-to-U editing occurred in both floral and leaf organs for orfB-CMS. These results strongly suggest that the orfB-CMS gene is closely associated with the petaloid phenotype and its expression is not regulated by RNA editing, but by post-transcriptional events.

Amino Acid Sequence↗

PubMed2001

Serum thioredoxin elucidates the significance of serum ferritin as a marker of oxidative stress in chronic liver diseases.

BACKGROUND/AIMS: Serum thioredoxin (TRX) levels have recently been established as an indicator of oxidative stress in various diseases. The aim of the present study was to clarify the clinical significance of serum ferritin in chronic liver diseases. METHODS: Levels of ferritin, transferrin saturation (TS), aspartate aminotransferase (AST), and TRX were measured in the sera of patients with chronic hepatitis C (CH-C, n=92), chronic hepatitis B (CH-B, n=28), nonalcoholic fatty liver (FL, n=31), or alcoholic liver diseases (ALD, n=17). Serum TRX levels were evaluated with a recently established sandwich enzyme-linked immunosorbent assay kit. RESULTS: Serum TRX levels were significantly higher in CH-C, FL, and ALD than in healthy volunteers. A larger proportion of patients with CH-C, FL, and ALD had elevated levels of serum ferritin than CH-B. Serum ferritin levels were positively correlated with levels of TS, AST, and TRX in CH-C, but were merely correlated with TS values in CH-B. Ferritin levels were also well correlated with AST and TRX, but not with TS in FL and ALD. CONCLUSION: Oxidative stress, which was evaluated by measuring serum TRX, in addition to storage iron and hepatocyte damage is a cause of increasing serum ferritin levels in chronic liver diseases. An elevated serum ferritin level, which was correlated with TS, indicates that iron-induced oxidative stress contributes to CH-C. Elevated ferritin levels in FL and ALD may be mostly due to iron-unrelated stresses.

Adult↗

PubMed2001

Purinergic regulation of intracellular Ca2+ concentration of rat pituitary folliculo-stellate cells in primary culture.

Pituitary folliculo-stellate cells (FSCs) are glia-like cells in the anterior pituitary and are believed to modulate the activity of the pituitary endocrine cells. However, little is known what regulates the activity of FSCs. We hypothesized that ATP could act on FSCs, because ATP is coreleased with pituitary hormones from endocrine cells. To test this possibility, we examined the effect of ATP by measuring intracellular Ca2+ concentration [Ca2+]i of FSCs in primary culture. Both ATP and UTP increased the [Ca2+]i in a concentration-dependent manner in a range between 0.1 microM and 10 microM. The response was completely suppressed by thapsigargin, an inhibitior of endoplasmic reticulum Ca2+-ATPase, and was significantly suppressed by U-73122, an inhibitor of phospholipase C. The response was also suppressed by caffeine, a blocker of IP3 receptor, whereas that was not suppressed by ryanodine, an antagonist of ryanodine receptor. These results indicate that ATP increases [Ca2+]i of FSCs by activating phospholipase C via P2Y purinergic receptor and suggest that ATP would be one of paracrine factors to FSCs in the anterior pituitary.

Adenosine Triphosphate↗

PubMed2001

Glutamate induces focal adhesion kinase tyrosine phosphorylation and actin rearrangement in heterologous mGluR1-expressing CHO cells via calcium/calmodulin signaling.

Group 1 metabotropic glutamate receptors (mGluR1 and mGluR5) stimulate phospholipase C (PLC) and lead to mobilization of intracellular Ca(2+) and activation of protein kinase C (PKC). In this investigation, using heterologous receptor-expressing Chinese hamster ovary (CHO) cells, we showed that stimulation of mGluR1 or mGluR5 with glutamate rapidly increases tyrosine phosphorylation of focal adhesion kinase (FAK) (maximum at 1-3 min) in a dose-dependent manner (half-maximal responses at approximately 2 microM). In mGluR1-expressing cells, the glutamate-induced increase of FAK tyrosine phosphorylation was blocked by not only the PLC inhibitor, U73122, but also depletion of intracellular Ca(2+) and effectively abrogated by calmodulin (CaM) inhibitors, calmidazolium and fluphenazine. However, neither the PKC inhibitor, GF109203X, nor the CaM kinase II inhibitor, KN-62, inhibited glutamate-stimulated FAK tyrosine phosphorylation. Stimulation of mGluR1 caused a marked increase in actin stress fiber formation. Importantly, this actin rearrangement was prevented by the CaM inhibitor, but not by the PKC inhibitor and is thus in a good agreement with the signaling cascade of the mGluR1-FAK pathway. These results suggest that the Ca(2+)/CaM signaling and its downstream FAK tyrosine phosphorylation play an important role in cellular function of mGluR1.

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

PubMed2001

Platelet-derived growth factor is involved in the augmentation of airway responsiveness through remodeling of airways in diesel exhaust particulate-treated mice.

BACKGROUND: Thickening of the region adjacent to the basement membrane is a key component of the remodeling of the asthmatic airway and is caused by collagen deposition in the region. OBJECTIVE: We sought to clarify the role of platelet-derived growth factor (PDGF), a competence factor of fibroblast, in the enhanced airway responsiveness and remodeling in a murine model. METHODS: Diesel exhaust particulates (DEPs) were administered intranasally every other day for 2 weeks with or without anti-PDGF-beta neutralizing antibody or goat IgG. Pulmonary function was then analyzed by using whole-body plethysmography before and after acetylcholine inhalation. RESULTS: Anti-PDGF-beta neutralizing antibody significantly inhibited both the elevation of airway resistance elicited by 1.25 and 2.5 mg/mL acetylcholine and the increase in the airway wall thickening induced by DEPs. In addition, bronchoalveolar lavage fluid cell analysis revealed that anti-PDGF-beta neutralizing antibody did not affect cellular infiltration at the airways. CONCLUSION: PDGF plays an important role in the process of remodeling brought about by DEP exposure in mice.

3T3 Cells↗

PubMed2001

Identification and characterization of an antibacterial peptide of the 26-kDa protease of Sarcophaga peregrina with antibacterial activity.

Previously, we purified a serine protease with a molecular mass of 26 kDa that exhibits potent antibacterial activity from a pupal extract of Sarcophaga peregrina (flesh fly). We divided this protease into 12 peptides and examined their antibacterial activity. A peptide corresponding to residues 155 to 174 (peptide 9) was found to exhibit antibacterial activity comparable to that of the 26-kDa protease. When Escherichia coli was treated with peptide 9, the permeability of both the outer and inner membranes increased, and substrates for beta-lactamase and beta-galactosidase entered the cells, but beta-galactosidase did not leak out of the cells under these conditions. It was suggested that residues 6 to 18 of peptide 9 form an amphiphilic alpha-helix under hydrophobic conditions with an N-terminal basic loop and then interact with acidic phospholipids in the bacterial membranes.

Amino Acid Sequence↗

PubMed2001

A phycocyanin-deficient mutant of synechocystis PCC 6714 with a single-base substitution upstream of the cpc operon.

The structure and expression of the cpc operon encoding phycocyanin subunits and linker polypeptides in a phycocyanin-deficient mutant (PD-1) and the wild-type of Synechocystis PCC 6714 were analyzed. The results of sequence and Northern blot analyses of the wild type indicate that the cpc operon consists of cpcB, cpcA, cpcC1, cpcC2 and cpcD, in that order. The levels of the transcripts in PD-1 were one-tenth to one-sixth as high as those in the wild type. In the PD-1 genome, a single-base substitution of C for T has occurred at base 259 upstream of the translational initiation codon of cpcB (at three bases downstream of the putative -10 region). To evaluate the in vivo transcription activities of these promoters in a cyanobacterium, we constructed vectors for the transformation of Synechococcus PCC7942, pANY1 and pANY2, which contain the upstream region of cpcB of the wild type (pANY1) or PD-1 (pANY2) and the promoter-less luxAB fusion. The bioluminescence of the transformants with pANY2 was one-tenth to one-sixth as high as that with pANY1. The coincidence of the results of Northern analysis and the promoter assay shows that the phycocyanin deficiency of PD-1 is due to the single-base substitution in the upstream region of the cpc operon.

Base Sequence↗

PubMed2001

Clarification of the relationship between the members of the family Thermomonosporaceae on the basis of 16S rDNA, 16S-23S rRNA internal transcribed spacer and 23S rDNA sequences and chemotaxonomic analyses.

To resolve relationships between members of the family Thermomonosporaceae, phylogenetic analyses using three sets of nucleotide sequences from 16S rDNA, 23S rDNA and the 16S-23S internal transcribed spacer (ITS) were carried out. Nearly all species of the family were included in this study. On the basis of congruous phylogenetic results and chemotaxonomic data, the following proposals are made. First, Actinomadura libanotica, Actinomadura aurantiaca, Actinomadura glomerata and Actinomadura longicatena are transferred to the genus Actinocorallia as Actinocorallia libanotica comb. nov., Actinocorallia aurantiaca comb. nov., Actinocorallia glomerata comb. nov. and Actinocorallia longicatena comb. nov., respectively. All the species of this genus are phylogenetically coherent and of phospholipid type PII (presence of phosphatidylethanolamine), distinguishing them from other Actinomadura species that are of phospholipid type PI (absence of diagnostic phospholipids). Second, Excellospora viridilutea is transferred to the genus Actinomadura as Actinomadura viridilutea comb. nov. As a result of the proposed transfers, the family Thermomonosporaceae now contains four genera Thermomonospora, Actinomadura, Actinocorallia and Spirillospora. The genus Actinocorallia and family Thermomonosporaceae are redescribed.

Actinomycetales↗

PubMed2001

Expression of CYP2A6 in tumor cells augments cellular sensitivity to tegafur.

To examine the role of cytochrome P450 2A6 (CYP2A6) in the cellular sensitivity to an anti-tumor prodrug, tegafur (FT), a CYP2A6 cDNA construct was transfected into cells of a colon cancer cell line, DLD-1. CYP2A6-expressing cells (DLD-1 / CYP2A6 cells) more efficiently catalyzed the conversion of FT to 5-fluorouracil (5-FU) (2.6-fold) and the 7-hydroxylation of coumarin (7.9-fold) than cells transfected with a null construct (DLD-1 / null cells). These results indicated that the expressed CYP2A6 was functionally active. The extent of growth inhibition of the DLD-1 / CYP2A6 cells by FT was greater than that of DLD-1 / null cells; the difference between the DLD-1 / CYP2A6 and DLD-1 / null cells was statistically significant at the concentrations of 250, 500 and 1000 mM. 5-FU, an active metabolite of FT, inhibited the growth of both types of cells to the same extent. Thus, intracellular expression of CYP2A6 can sensitize cells to FT.

Antimetabolites, Antineoplastic↗

PubMed2001

CPT-11 may provide therapeutic efficacy for esophageal squamous cell cancer and the effects correlate with the level of DNA topoisomerase I protein.

CPT-11 is a potent anti-cancer drug and a specific inhibitor of DNA topoisomerase I (Topo I). In this study, we aim to evaluate the effects of CPT-11 on esophageal squamous cell cancers (ESCC) and to determine the correlation between the effects and the levels of Topo I expression. We examined the growth-inhibitory effect caused by SN-38, an active metabolite of CPT-11, in 14 human ESCC cell lines established from 10 primary and 4 metastatic lesions. CPT-11 was considered effective against 5 cell lines from primary lesions and one from metastatic lesions, and thus may show therapeutic efficacy against both primary and metastatic ESCC tumors. Although Topo I mRNA levels in these 14 ESCC cell lines, as quantitated by northern blot analysis, showed no correlation with the IC(50) values, Topo I protein levels, as quantitated by western blot analysis, showed an inverse correlation with the IC(50) values. Topo I protein levels could be an indicator of sensitivity to CPT-11. We also determined Topo I protein levels in 40 ESCC tumors and matched normal mucosae. Thirty-four tumors showed 1.2 - 22.3-fold increases in Topo I levels. Two patients receiving pre-operative chemotherapy and one receiving radiotherapy exhibited increased Topo I protein levels in their tumor lesions. It appeared that CPT-11 could provide selective therapeutic efficacy against ESCC tumors. CPT-11 may be effective for the treatment of metastatic ESCC tumors and as a second-line anti-cancer drug for ESCC.

Blotting, Western↗

PubMed2001

Identification of a novel T-cell epitope in soluble egg antigen of Schistosoma japonicum.

Identification of T-cell epitopes harbored in soluble egg antigen (SEA) of Schistosoma japonicum and study of the immunological properties are essential for understanding the immunopathology and the control of schistosomiasis. As a follow-up to our previous work, the 66- to 80-kDa fragment from SEA was partially digested with protease, fractionated by reverse-phase high-pressure liquid chromatography, and found to be carrying a peptide which stimulated proliferation and gamma interferon (IFN-gamma) production of Th1 clones specific to SEA. Sequence analysis showed that the peptide was composed of 12 amino acids lined up as DLAVELAYLGNL. A synthetic homologue induced proliferation and IFN-gamma and interleukin-2 (IL-2) production, but not IL-4 or IL-6 production, by the Th1 clones as well as by the spleen cells from SEA-immunized mice, thus indicating that the peptide carries a Th1 epitope of SEA.

Animals↗

PubMed2001

Effects of carvedilol on left ventricular function, mass, and scintigraphic findings in isolated left ventricular non-compaction.

A four month old infant with isolated left ventricular non-compaction was treated with carvedilol. Haemodynamic studies and various types of imaging-including echocardiography, radiographic angiography, magnetic resonance imaging, and single photon emission computed tomography with (201)Tl, (123)I-beta-methyliodophenylpentadecanoic acid (BMIPP), and (123)I-metaiodobenzylguanidine (MIBG)-were performed before and 14 months after treatment. Left ventricular ejection fraction increased from 30% to 57%, and left ventricular end diastolic volume, end systolic volume, and end diastolic pressure showed striking reductions during treatment. Left ventricular mass decreased to about two thirds of the baseline value after treatment. Per cent wall thickening increased after carvedilol in the segments corresponding to non-compacted myocardium. A mismatch between (201)Tl and BMIPP uptake in the area of non-compaction observed before carvedilol disappeared after treatment. Impaired sympathetic neuronal function shown by MIBG recovered after treatment. Thus carvedilol had beneficial effects on left ventricular function, hypertrophy, and both metabolic and adrenergic abnormalities in isolated left ventricular non-compaction.

3-Iodobenzylguanidine↗

PubMed2001

Acetylcholine increases intracellular Ca2+ in the rat pituitary folliculostellate cells in primary culture.

Pituitary folliculostellate cells (FSCs) are thought to partially inhibit pituitary hormone secretion through a paracrine mechanism. In this process, one of the important questions is what factors regulate the function of FSCs. Because ACh is synthesized in and possibly released from the corticotrophs and lactotrophs, we examined whether FSCs respond to ACh by the method of Ca2+ imaging in primary cultured FSCs from male Wistar rats. ACh (30 nM-3 microM) increased intracellular calcium concentration ([Ca2+](i)) of FSCs in a concentration-dependent manner, with an initial rapid rise followed by a relatively sustained increase. The complete block of the response by atropine and pirenzepine suggests involvement of muscarinic receptors. Depletion of the stored Ca2+ by thapsigargin blocked the response completely. Blockers of phospholipase C, U-73122 and neomycin, suppressed significantly the rise of [Ca2+](i). These results suggest that ACh increases [Ca2+](i) in FSCs by activating phospholipase C, presumably through activation of M(1) receptors. The rise in [Ca2+](i) could trigger a variety of Ca2+-dependent cellular processes, including the synthesis and release of bioactive substances, which in turn act on endocrine cells.

Acetylcholine↗

PubMed2001

Purification of the major allergen of red soft coral (Dendronephthya nipponica).

Red soft coral (RSC; Dendronephthya nipponica, a marine coelenterate) causes spiny lobster fishermen living along the Pacific coast of Miyazaki Prefecture in Japan to develop occupational allergies, such as conjunctivitis, rhinitis, dermatitis and bronchial asthma. The aim of this study was to purify and to characterize RSC allergen, which causes occupational asthma in spiny lobster fishermen. The allergic responsiveness of spiny lobster fishermen to RSC was examined. The examinations included specific IgE production, skin test responses, lymphocyte stimulation tests and specific IgG production. We found that RSC has a strong sensitizing activity in humans at a molecular weight of 10 kD or more, while it has no IgE-producing activity at a molecular weight of less than 10 kD. Neither the nonatopic controls nor the atopic non-coral-allergic controls exhibited any RAST-binding activity to any fraction. For the purification and the identification of this new allergen component, repeated gel filtration of the RSC extract was performed on a Sephacryl S-200 column, followed by gel filtration on a Superose-6 column. The purified major allergen component Den n 1, which is separated on a Mono-Q column, showed intradermal responses, lymphocyte stimulating activity and specific IgG-producing activity in RSC-induced bronchial asthma patients. The 53-kD component was electroblotted on a polyvinylidene difluoride membrane. The N-terminal amino acid sequence of this new allergen component (Den n 1) was determined as Asp-Asp-Ile-Asn-Arg-Tyr-Ala-Phe-Asp-Asn-Lys-Ile-Asn- Asp-Lys-Leu-Phe-Asp-His-Trp-Gln-Ser.

Adult↗

PubMed2001

Characterization of the pro-aminopeptidase from Aeromonas caviae T-64.

The pro-aminopeptidase from Aeromonas caviae T-64 (pro-apAC) had maximal activity at 60 degrees C and was more stable than mature apAC at temperature up to 65 degrees C for 1 hour. The pH stability of pro-apAC ranged from 4.0 to 8.0, which is broader than the range for the mature apAC. The kcat/Km of pro-apAC was 1.4% to 24% of that of mature apAC.

Aeromonas↗