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M Horiuchi

Publications and source records attributed to M Horiuchi.

At least 145 records · Page 8Linked to original sources
PubMed1997

Basaloid squamous carcinoma of the larynx: report of a case.

Basaloid squamous carcinoma (BSC) is a rare neoplasm. We present a case of basaloid squamous carcinoma of the larynx in a 57-year-old male patient. The diagnosis before treatment was supraglottic carcinoma (T3N1MO) and biopsy of the larynx revealed a poorly differentiated squamous cell carcinoma. Total laryngectomy and right radical neck dissection were performed, and pathological studies of a specimen removed from the larynx revealed BSC of the larynx. The patient's postoperative progress was uneventful, however, 12 months later he developed lung metastasis of the left side. The patient underwent partial resection of the lung. He developed recurrence of lung metastasis 6 months later. Chemotherapy with cisplatin (CDDP) and vindesine sulfate (VSD) was administered in two courses, but the efficacy was evaluated as no change (NC). At present, 26 months after the first visit, he has been asymptomatic with lung metastasis, and there was no evidence of recurrence in the neck.

Carcinoma, Basosquamous↗
PubMed1997

Suppressed expression of the urea cycle enzyme genes in the liver of carnitine-deficient juvenile visceral steatosis (JVS) mice in infancy and during starvation in adulthood.

Systemic carnitine-deficient juvenile visceral steatosis (JVS) mice exhibit decreased expression of some liver-selective genes including those for the urea cycle enzymes during the infantile period. At 25 days, carbamoylphosphate synthetase (CPS) mRNA level was remarkably low in the liver of JVS mice, and the HNF-4 and C/EBP-alpha mRNA contents were also reduced. HNF-3 alpha and C/EBP-beta mRNAs were slightly higher in the liver of JVS mice, and HNF-1 mRNA remained normal. These results, together with the developmental changes of these transcription factor mRNA levels, suggest that HNF-4 and C/EBP-alpha are involved in the suppression of CPS expression. If JVS mice survived the crisis at 4-5 weeks, their body weight caught up with that of control mice around 7 weeks. The steady-state levels of CPS and argininosuccinate synthetase (ASS) mRNAs in the liver of JVS mice were normalized by no later than 8 weeks. Starvation for 48 h caused an increase of about twofold in CPS and ASS mRNA levels in the liver of control mice, while the same treatment failed to increase their levels in the liver of JVS mice. The starvation similarly caused increases in HNF-4 and C/EBP-beta mRNA levels in the liver of both control and JVS mice, but the increases were significantly less in JVS mice than in control mice. Thus, the lack of induction of CPS and ASS mRNAs during development and under starvation in JVS mice correlated with the lower induction of HNF-4 and C/EBP-alpha mRNAs, and of HNF-4 and C/ EBP-beta mRNAs, respectively. Furthermore, all these changes seemed to correlate with the presence of fatty liver and the high serum free fatty acid levels, suggesting that disturbance of fatty acid metabolism affects nitrogen metabolism at least in part via altered gene expression of transcription factors such as HNF-4, C/EBP-alpha, and C/EBP-beta.

Age Factors↗
PubMed1997

Dimerization and DNA binding facilitate alpha-helix formation of Max in solution.

Max is a basic region/helix-loop-helix/leucine zipper (b/HLH/Z) protein that forms a hetero-complex with the Myc family proteins Myc, Mad, and Mxi1, and a homo-complex with itself. These complexes specifically bind to double-stranded DNA containing CACGTG sequences. Here, we report on the structural properties in aqueous solution of a 109-amino-acid protein, Max110, corresponding to the N-terminal domain of Max containing the b/HLH/Z motif (residues 2-110), as characterized by combined use of circular dichroism (CD) and sedimentation equilibrium experiments. The results showed that the alpha-helical content of Max110 increases with increasing protein concentration. The sedimentation equilibrium data indicated that Max110 exists as a monomer at low protein concentration, and forms a dimer at high protein concentration. Further increases in the alpha-helical content of Max110 occur upon addition of DNA with the CACGTG recognition sequence. Thus, dimerization and binding to DNA of Max both favor an increase of the alpha-helical content.

Amino Acid Sequence↗
PubMed1997

Triplet repeat polymorphism in the NOTCH4 gene with the human major histocompatibility complex in a healthy population and patients with a salivary gland tumor in Japan.

The NOTCH4 gene, the human counterpart of the mouse mammary tumor gene, int-3, has been recently localized near the boundary of the HLA class II and class III regions. This gene is one of candidates for development of salivary gland tumor. Microsatellite polymorphism of (CTG)n repeat in the signal peptide domain of NOTCH4 was analyzed in Japanese including the patients with salivary gland tumor. Four alleles consisting of 6, 9, 10 and 11 repetitions of CTG (Leu) were observed and found to be in linkage disequilibria with HLA class I and class II alleles. No significant association of this microsatellite polymorphism with the disease were observed in 26 samples of salivary gland tumor. In this neoplasia, neither large-scale deletion nor translocation was detected around the NOTCH4 gene using genomic Southern hybridization analysis by the NOTCH4 cDNA as a probe.

Alleles↗
PubMed1997

Effects of acidification on growth and glycolysis of Streptococcus sanguis and Streptococcus mutans.

After carbohydrate intake, pH in dental plaque decreases rapidly and reaches about 4 within a few minutes. The acidification not only promotes demineralization of tooth surface but can also cause damage to bacteria in dental plaque. We, therefore, investigated the effect of acidification on the dental plaque bacteria Streptococcus sanguis and Streptococcus mutans. At pH 4.0 and 4.2, both growth and glycolytic activities in these streptococci were repressed. Prolonged acidification (for 60 min at pH 4.0) not only repressed both growth and glycolytic activities but also impaired them in S. sanguis cells with concomitant inactivation of the glycolytic enzymes, hexokinase, phosphofructokinase, glyceraldehydephosphate dehydrogenase and enolase. The impaired abilities of glycolysis and growth recovered following incubation at pH 7.0 for 80-90 min, and this was accompanied by reactivation of the glycolytic enzymes. On the other hand, these impairments were not observed in S. mutans cells exposed to prolonged acidification. These results indicate that the low pH frequently occurring in dental plaque may transiently impair streptococcal glycolysis and growth and that S. mutans is more durable to the acidification than S. sanguis.

Culture Media, Conditioned↗
PubMed1997

Photoinactivation of virus infectivity by hypocrellin A.

We investigated the photoinactivation of virus infectivity by hypocrellin A and its mechanism. The titers of vesicular stomatitis virus (VSV) and human immunodeficiency virus type 1 (HIV-1), both of which are enveloped viruses, were reduced upon illumination with hypocrellin A in a concentration-dependent manner, whereas canine parvovirus, a nonenveloped virus, was not killed. The removal of oxygen or addition of sodium azide or beta-carotene both inhibited VSV inactivation. Mannitol and superoxide dismutase had no effect on VSV inactivation. These results indicate that singlet oxygen was involved in the process of VSV inactivation. Of the three major VSV membrane proteins, peripheral membrane protein M was most damaged by the hypocrellin A phototreatment.

Animals↗
PubMed1997

Molecular Delivery System for Antisense Oligonucleotides: Enhanced Effectiveness of Antisense Oligonucleotides by HVJ-liposome Mediated Transfer.

BACKGROUND: The effectiveness of antisense oligodeoxynucleotides for in vitro and in vivo studies is limited by a low efficiency of cellular uptake and instability due to degradation by nucleases. To overcome some of these problems, we recently developed a transfer method that utilizes inactivated Sendai virus (hemagglutinating virus of Japan [HVJ]) complexed with liposomes to deliver antisense oligodeoxynucleotides. In this study, we compared the effectiveness of the HVJ-liposome method versus a cationic liposome method versus passive uptake to deliver antisense oligodeoxynucleotides against basic fibroblast growth factor on angiotensin (Ang) II-induced rat vascular smooth muscle cell growth. METHODS AND RESULTS: Twenty to twenty-eight hours after transfection, antisense fibroblast growth factor oligodeoxynucleotides introduced by passive uptake and HVJ-liposome method decreased basal DNA synthesis significantly as compared to the sense, control, and scrambled oligodeoxynucleotides groups; however, 60-68 hours after transfection, only antisense fibroblast growth factor oligodeoxynucleotides transduced by the HVJ-liposome method resulted in a significant inhibition of DNA synthesis under basal and Ang II-(10(-;6)M) stimulated conditions. The IC(25) of oligodeoxynucleotides assessed by the inhibition of thymidine incorporation was significantly lower using the HVJ-liposome method than those using the other transfer methods. To clarify the mechanisms of cellular uptake of oligodeoxynucleotides with the HVJ-liposome method, we studied the cellular fate of fluorescein isothiocyanate (FITC)-labeled oligodeoxynucleotides FITC-oligodeoxynucleotides was localized in nuclei at 5 minutes after transfection with the HVJ-liposome method. In contrast, FITC-oligodeoxynucleotides introduced by passive uptake was detected in nonnuclear cellular compartments, possibly endosomes, but not the nuclei. Cellular fluorescence of oligodeoxynucleotides introduced by passive uptake disappeared within 24 hours, while that introduced by the HVJ-liposome method could be observed up to 72 hours. CONCLUSION: These results demonstrate that the HVJ-liposome transfer enhanced the effectiveness of AS-fibroblast growth factor via its specific molecular mechanisms of transfer.

Journal Article↗
PubMed1997

The effect of carnitine on ketogenesis in perfused livers from juvenile visceral steatosis mice with systemic carnitine deficiency.

Juvenile visceral steatosis (JVS) mice have been reported to have systemic carnitine deficiency, and the carnitine concentration in the liver of JVS mice was markedly lower than that of controls (11.6 +/- 2.6 versus 393.5 +/- 56.4 nmol/g of wet liver). To evaluate the role of carnitine in mitochondrial beta-oxidation in liver, we examined the effects of carnitine on ketogenesis in perfused liver from control and JVS mice. In control mice, ketogenesis was increased by the infusion of 0.3 mM oleate, but not by L-carnitine. In contrast, although ketogenesis in JVS mice was not increased by the infusion of oleate, it was increased 2.5-fold by the addition of 1000 microM L-carnitine. Addition of 50, 100, and 200 microM L-carnitine increased ketogenesis in a dose-dependent manner. The infusion of 0.3 mM octanoate or butyrate increased ketogenesis in a carnitine-independent fashion in both control and JVS mice. These findings suggest that endogenous long chain fatty acids from accumulated triglycerides may be used as substrates in the presence of carnitine in JVS mice. The relationship between ketogenesis and free carnitine concentration was examined in livers from JVS mice. Ketogenesis increased as free carnitine levels increased until concentrations exceeded about 100 nmol/g of wet liver (340 microM). The free carnitine concentration required for half-maximal ketone body production in liver of JVS mice was 45 microM (13 nmol/g of wet liver), which corresponds to a K(m) value of carnitine palmitoyltransferase I. We conclude that carnitine is a rate-limiting factor for beta-oxidation in liver only when the carnitine level in liver is very low.

Animals↗
PubMed1997

Instability of the 12-nucleotide repeat in c-myb gene of bovine T-lymphoma cells.

Insertion of a 12-nucleotide repeat in c-myb gene exon 9 was observed in about 15% of sporadic bovine T-lymphomas. The 12-nucleotide repeat in the T-lymphoma cells showed deletion and insertion of the repeat units during cultivation of the cells. To know whether deficiency in DNA loop repair is involved in the instability of the repeat, abilities to bind and correct the loop structure in nuclear extracts were examined. The nuclear extracts of all examined cells had ability to bind and correct the loop structure. These data suggest that instability of the 12-nucleotide repeat in bovine T-lymphoma cells might be independent of deficiency of DNA loop repair function.

Animals↗
PubMed1997

Epitope mapping of a monoclonal antibody specific to feline panleukopenia virus and mink enteritis virus.

To obtain monoclonal antibodies (MAbs) specific to feline panleukopenia virus (FPLV) and mink enteritis virus (MEV), 15 hybridomas secreting MAbs against MEV-Abashiri were established and the properties of the MAbs were analyzed. The cross-reactivity of MAbs revealed that one MAb, P2-215 was specific for FPLV and MEV, whereas the remaining fourteen MAbs reacted with canine parvovirus (CPV), FPLV, and MEV. Epitope analyses using various CPV/MEV chimeric viruses revealed that the MAb P2-215 recognized the epitope comprised of amino acid 93-Lys in VP2, which is known to be FPLV and MEV-specific.

Amino Acid Sequence↗
PubMed1997

Characterization of the bovine prion protein gene: the expression requires interaction between the promoter and intron.

We cloned the part of the bovine PrP gene which contains the 5'-flanking region, exon 1, exon 2 and intron 1 to analyze its promoter region. The 5' non-coding region of the bovine PrP gene consisted of three exons and two introns, and its organization was similar to that of the mouse, rat and sheep PrP genes. The 5'-flanking region of the bovine PrP gene from the transcription start site to nucleotide position -88 was (G + C)-rich (78%) and contained three potential binding sites for the transcription factor Sp1, but no CCAAT-box or TATA-box. This region showed high homology (89%) with that of the sheep PrP gene, but relatively low homology (approximately 46-62%) with the same region of the mouse, rat, hamster and human PrP genes. The position from -88 to -30 within the 5'-flanking region of the bovine PrP gene showed major promoter activity. However, this region was able to function properly only in collaboration with the region at +123 to +891 of intron 1 of the bovine PrP gene.

Animals↗
PubMed1997

[An autopsy case of amyotrophic lateral screlosis (ALS): magnetic resonance imaging and pathological findings of the pyramidal tract].

A 59-year-old woman was diagnosed as amyotrophic lateral screlosis (ALS) on the basis of neurological and electromyographical findings, and died after about 4 years course. Magnetic resonance imaging (MRI) on coronal planes through the internal capsule revealed high signal area almost limited to the pyramidal tract; the high signal area was more restricted in proton weighted imaging than in T2 weighted imaging. Histological lesion of the precentral gyrus was slight, while loss of myelinated fibers in the posterior limb of the internal capsule was remarkable. Extent of the pathological lesion in the posterior limb of the internal capsule well corresponded to the high signal area in proton weighted imaging. Comparison of the pyramidal tract pathology in the corona radiata and the internal capsule in Klüver-Barrera preparations with the MRI findings obtained 2 years and 8 months before the autopsy suggests us that the T2 weighted imaging of ALS brains may detect involvement of the pyramidal tract as early as or even earlier than histological changes become manifest.

Amyotrophic Lateral Sclerosis↗
PubMed1996

Intracellular third loop domain of angiotensin II type-2 receptor. Role in mediating signal transduction and cellular function.

The present study tests the hypothesis that the unique intracellular third loop domain of angiotensin II type-2 (AT2) receptor is essential for the subsequent intracellular signaling and plays an important role in mediating receptor function. Synthetic intracellular third loop peptide of the AT2 receptor (AT2-3LP, 22 amino acids) and control peptide consisting of the same amino acid composition in random sequence were delivered into adult rat aortic vascular smooth muscle cells by cationic liposome-mediated transfection. Successful intracellular peptide delivery was confirmed by microscopic localization of the fluorescein-labeled AT2-3LP within the cells and also by co-immunoprecipitation of the 125I-labeled 3LP complexed with Gi protein using anti-Gialpha antibody. The AT2-3LP-transfected cells showed reduction of serum-stimulated DNA synthesis and cell proliferation as well as a decrease in mitogen-activated protein kinase activity, simulating the effects of AT2 receptor stimulation. The antagonistic effect of the AT2-3LP on mitogen-activated protein kinase activity and DNA synthesis were reversed by pertussis toxin and sodium orthovanadate. Thus, our data suggest that the intracellular third loop domain of the AT2 receptor is closely linked with the cellular signaling pathways of vascular smooth muscle cells in which Gi and protein-phosphotyrosine phosphatase are involved, resulting in the alteration of mitogen-activated protein kinase activity and in growth inhibition.

Amino Acid Sequence↗
PubMed1996

Predominant p53 mutations in enzootic bovine leukemic cell lines.

The role of the p53 tumor suppressor gene in bovine lymphosarcomas, a fragment of about 100 bp corresponding to approximately 97% of the open reading frame of the p53 gene was first amplified from single-strand cDNA originated from calf thymus by polymerase chain reaction PCR) and sequenced to obtain the bovine wild-type p53 gene. At the amino acid level, the omologies of the bovine p53 gene with the human, mouse, chicken and cat p53 genes were 0.9%, 72.8%, 52.7% and 82.3%, respectively. Moreover, eight bovine leukemic cells lines were studied for alterations in the p53 gene. These lines showed no significant somatic alterations in southern blot analysis, and expressed 2.5 kb p53-specific transcripts in Northern blot analysis. In mutation analysis using the reverse transcriptase-PCR technique, we detected three missense point mutations in four of these bovine leukemic cell lines. These mutations occurred in the 'hotspots' of the p53 gene. Thus p53 mutations predominantly occur in BLV-transformed cell lines and seem to be necessary for development of enzootic bovine leukosis (EBL).

Amino Acid Sequence↗
PubMed1996

Altered expression of carnitine palmitoyltransferase II in liver, muscle, and heart of mouse strain with juvenile visceral steatosis.

We conducted a quantitative study of the effect of carnitine deficiency on the mRNA level of carnitine palmitoyltransferase II in the liver, muscle and heart of mice with juvenile visceral steatosis, a strain that is systematically deficient in carnitine. The amount of carnitine palmitoyltransferase II mRNA was increased in liver and muscle of homozygotes, as compared with heterozygotes and normal controls, at 2, 4, and 8 wk of age. The mRNA levels of this enzyme were normalized after carnitine administration. The mRNA level of carnitine palmitoyltransferase II in the heart was increased only at 8 wk, and was not affected by carnitine administration. These results suggest that carnitine displays some effect on the mRNA level of the carnitine palmitoyltransferase II gene in liver and muscle, probably through fatty acid metabolic change.

Ammonia↗
PubMed1996

Angiotensin II type 2 receptor mediates programmed cell death.

The function of the recently discovered angiotensin II type 2 (AT2) receptor remains elusive. This receptor is expressed abundantly in fetus, but scantily in adult tissues except brain, adrenal medulla, and atretic ovary. In this study, we demonstrated that this receptor mediates programmed cell death (apoptosis). We observed this effect in PC12W cells (rat pheochromocytoma cell line) and R3T3 cells (mouse fibroblast cell line), which express abundant AT2 receptor but not AT1 receptor. The cellular mechanism appears to involve the dephosphorylation of mitogen-activated protein kinase (MAP kinase). Vanadate, a protein-tyrosine-phosphatase inhibitor, attenuated the dephosphorylation of MAP kinases by the AT2 receptor and restored the apoptotic changes. Antisense oligonucleotide to MAP kinase phosphatase 1 inhibited the AT2 receptor-mediated MAP kinase dephosphorylation and blocked the AT2 receptor-mediated apoptosis. These results suggest that protein-tyrosine-phosphatase, including MAP kinase phosphatase 1 activated by the AT2 receptor, is involved in apoptosis. We hypothesize that this apoptotic function of the AT2 receptor may play an important role in developmental biology and pathophysiology.

3T3 Cells↗
PubMed1996

Improvement of PrPSc-detection in mouse spleen early at the preclinical stage of scrapie with collagenase-completed tissue homogenization and Sarkosyl-NaCl extraction of PrPSc.

Scrapie in sheep has recently become again a target of control measures and eradication programs. Crucial for the effectiveness of these measures is the detection of infected sheep during the long and potentially hazardous incubation period. However, routine-diagnosis is mostly limited to clinical examinations when disease becomes apparent, and to postmortem investigations. Through the detection of the scrapie-specific isoform of the prion protein (PrPSc) by Western blot in the spleen and lymph nodes from scrapie-infected mice and sheep, we have shown previously that diagnosis during the preclinical stage is possible. We introduce here an improved method for the diagnosis of mouse scrapie shortly after infection. Through a homogenization procedure that includes a collagenase digestion step, and through extraction and salting-out of PrPSc by Sarkosyl and NaCl, respectively, we were able to detect PrPSc in spleen tissue of intraperitoneally infected mice seven days postinfection. Moreover, the new protocol makes sample-handling easier and reduces the hands-on time. We also successfully enriched PrPSc from spleen tissue through immobilized metal affinity chromatography (IMAC); however, for the diagnosis at the earliest stage of infection, extraction of PrPSc by Sarkosyl and NaCl was more effective.

Animals↗