Biomedical subjects

Masashi Suzuki

Publications and source records attributed to Masashi Suzuki.

At least 19 recordsLinked to original sources

PubMed2007

Lovastatin insensitive 1, a Novel pentatricopeptide repeat protein, is a potential regulatory factor of isoprenoid biosynthesis in Arabidopsis.

Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Despite the compartmentalization of these two pathways, metabolic flow occurs between them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cross-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA insertion mutant lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways, i.e. sterols and chlorophyll, was less affected by lovastatin and clomazone, respectively, in loi1 than in the wild type. Furthermore, the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity analysis showed higher activity of HMGR in loi1-1 treated with lovastatin than that in the WT. We consider that the lovastatin-resistant phenotype of loi1-1 was derived from this post-transcriptional up-regulation of HMGR. The LOI1 gene encodes a novel pentatricopeptide repeat (PPR) protein. PPR proteins are thought to regulate the expression of genes encoded in organelle genomes by post-transcriptional regulation in mitochondria or plastids. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation revealed that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.

Arabidopsis↗

PubMed2006

Successful treatment of nasal septum hemangioma with the Harmonic Scalpel: a case report.

Hemangioma of the nasal septum, known as "bleeding polyp," is an occasional lesion in adults. We report two cases of bleeding polyps, that were successfully treated by surgery using the Harmonic Scalpel (HS). Two women (aged 58 and 67 years) presented with unilateral nasal hemangioma, which was revealed by unilateral epistaxis. Both the women were treated by surgical excision using the HS under general and local anesthesia, respectively. Treatment involves surgical excision of the tumor including the mucosa and the underlying perichondrium. HS is an effective tool for the excision of bleeding polyps with less bleeding and less tissue injury.

Aged↗

PubMed2006

Lanosterol synthase in dicotyledonous plants.

Sterols are important as structural components of plasma membranes and precursors of steroidal hormones in both animals and plants. Plant sterols show a wide structural variety and significant structural differences from those of animals. To elucidate the origin of structural diversity in plant sterols, their biosynthesis has been extensively studied [Benveniste (2004) Annu. Rev. Plant. Biol. 55: 429, Schaller (2004) Plant Physiol. Biochem. 42: 465]. The differences in the biosynthesis of sterols between plants and animals begin at the step of cyclization of 2,3-oxidosqualene, which is cyclized to lanosterol in animals and to cycloartenol in plants. However, here we show that plants also have the ability to synthesize lanosterol directly from 2,3-oxidosqualene, which may lead to a new pathway to plant sterols. The Arabidopsis gene At3g45130, designated LAS1, encodes a functional lanosterol synthase in plants. A phylogenetic tree showed that LAS1 belongs to the previously uncharacterized branch of oxidosqualene cyclases, which differs from the cycloartenol synthase branch. Panax PNZ on the same branch was also shown to be a lanosterol synthase in a yeast heterologous expression system. The higher diversity of plant sterols may require two biosynthetic routes in steroidal backbone formation.

Amino Acid Sequence↗

PubMed2006

Equilibrium test findings in patients with Bell's palsy.

OBJECTIVE: We analyzed equilibrium test findings in patients with Bell's palsy to confirm that such findings occur not only in patients with Hunt's syndrome but also in patients with Bell's palsy. METHODS: Subjects were 83 patients with Bell's palsy, 45 patients with Hunt's syndrome, and 82 patients with unilateral chronic otitis media without history of vertigo or ear surgery (for control). They were treated in our inpatient department and underwent equilibrium testing during the period 1983-2002. All subjects were at least 20 years of age. The following were analyzed: (1) presence of vertigo, (2) presence of abnormal equilibrium test findings, (3) relation between the degree of paralysis and abnormal equilibrium test findings, and (4) relation between the degree of recovery from paralysis and abnormal equilibrium test findings. Equilibrium testing consisted of a gaze nystagmus test, a spontaneous nystagmus test, positional and positioning nystagmus tests, and a caloric test. The incidence of abnormal findings in each test was compared between the three groups. RESULTS: Abnormal equilibrium test findings were observed in patients with Bell's palsy. No association was observed between the results of equilibrium tests and the degree of facial paralysis in patients with Bell's palsy. However, some of the equilibrium test results were significantly associated with the degree of facial nerve recovery. CONCLUSIONS: Although our study was limited in its lack of true control subjects, our data suggest that patients with Bell's palsy show a significantly high incidence of vestibular abnormalities.

Adult↗

PubMed2006

In vivo interaction between Tobacco mosaic virus RNA-dependent RNA polymerase and host translation elongation factor 1A.

Several host translation elongation factors have been suggested to play essential roles in the replication and translation of viral RNAs in plants, animals and bacteria. Here, we show the interaction between eukaryotic translation elongation factor 1A (eEF1A) and Tobacco mosaic virus (TMV) RNA-dependent RNA polymerase (RdRp) in vivo by immunoprecipitation. The tobacco eEF1A interacted not only with 3'-untranslated region (3'-UTR) of TMV RNA but also directly with RdRp without mediation by the 3'-UTR. The methyltransferase domain of TMV RdRp was indicated to be responsible for the interaction with eEF1A in vitro and in yeast. These results suggest that eEF1A is a component of the virus replication complex of TMV.

3' Untranslated Regions↗

PubMed2006

Effects of low-intensity focused ultrasound on the mouse submandibular gland.

Ultrasound is expected to make a considerable contribution to drug delivery systems (DDSs). We tested the hypothesis that low-intensity focused ultrasound (LIFU) increases vessel permeability in the mouse submandibular gland without causing parenchymal damage. In a preliminary study, LIFU at 3 W/cm2 with a 50% duty cycle for 2 minutes did not cause histologic damage. We therefore applied LIFU to mouse submandibular gland at these conditions before and after injecting horseradish peroxidase. Single labeling laser scanning confocal microscopy revealed positive horseradish peroxidase staining around the excretory ducts in the mucous-producing part of the gland, but absence of staining in control glands. Immunostaining for fibrinogen was positive in the same region. Fibrinogen is an intravascular protein that does not pass through intact vessels. These findings suggest that LIFU increases vessel permeability and disruption without destruction. It is anticipated that this process will be useful in establishing a DDS that uses LIFU.

Animals↗

PubMed2006

Safety and efficacy of nasal application of CpG oligodeoxynucleotide as a mucosal adjuvant.

OBJECTIVES: Nasal vaccination is an effective regimen to prevent upper respiratory infections. An appropriate adjuvant is required for the development of a nasal vaccine. The safety and efficacy of CpG oligodeoxynucleotide (ODN) as a mucosal adjuvant was examined. METHODS: Mice were nasally administered various doses of CpG ODN weekly, a total of three times. Histologic changes in the spleen and the nasal mucosa were examined, and the alterations in cell subpopulations were analyzed by flow cytometry. In addition, the mice were nasally immunized with P6 outer membrane protein of nontypeable Haemophilus influenzae (NTHi) and CpG ODN, and P6-specific immune responses were examined. RESULTS: No inflammation or tissue damage was observed locally or systemically after nasal administration, even with a high dose of CpG ODN. A high dose of CpG ODN induced an increase in CD8+ T cells in the nasal mucosa and B cells in the spleen. When CpG ODN was coadministered with P6, P6-specific mucosal and systemic immune responses were effectively induced, since high levels of the specific IgA and IgG were detected in the nasal wash and serum, respectively. CONCLUSIONS: These findings suggest that CpG ODN is a safe and effective mucosal adjuvant. Further, nasal vaccination with P6 and CpG ODN might be an effective regimen to prevent upper respiratory infections.

Adjuvants, Immunologic↗

PubMed2006

Nasal vaccination with CpG oligodeoxynucleotide induces protective immunity against non-typeable Haemophilus influenzae in the nasopharynx.

OBJECTIVES: Nasal vaccination is an effective therapeutic regimen for preventing otitis media. Since cholera toxin (CT) is toxic, an alternative adjuvant is required for the development of a nasal vaccine. The efficacy of CpG oligodeoxynucleotide (ODN) as a mucosal adjuvant was examined. METHODS: Mice were immunized intranasally with P6 protein of non-typeable Haemophilus influenzae (NTHi) and adjuvant, CT, or CpG ODN, and P6-specific antibody responses were examined. The expression of P6-specific cytokine mRNA in splenic CD4 T cells was also determined. In addition, NTHi challenges were performed and the NTHi was quantified in nasal washes. RESULTS: P6-specific IgA in nasal wash and serum IgG titers were elevated significantly after nasal immunization. The IgG1/IgG2a ratio in serum from P6+CpG-immunized mice was less than that of P6+CT-immunized mice. Although IL-6 was expression similarly in both groups, IFN-gamma expression was greater in P6+CpG-immunized mice than in P6+CT-immunized mice. Enhanced clearance of NTHi from the nasopharynx was also shown equally in both groups. CONCLUSION: These results indicate that CpG ODN might be an effective mucosal adjuvant, acting by mechanisms that are different from CT. These findings suggest that nasal vaccination with P6 and CpG ODN might be an effective regimen for the induction of NTHi-specific protective immunity.

Adjuvants, Immunologic↗

PubMed2006

Solitary fibrous tumor of the thyroid gland: report of two cases and review of the literature.

Presented herein are the first two Japanese cases of solitary fibrous tumor (SFT) of the thyroid gland. The patients were 64- and 41-year-old men, who underwent hemithyroidectomy for thyroid tumors. Histopathologically, the tumors were well circumscribed, and were composed of spindle cells, collagen bundles and entrapped thyroid follicles. Spindle cells and collagen bundles were mostly in a patternless arrangement with an admixture of hypo- and hypercellular areas. Proliferating spindle cells were bland, slender, and occasionally wavy without any atypia and increased mitotic figures. Immunohistochemically, they were strongly positive for CD34, CD99, and bcl-2, but negative for epithelial membrane antigen, keratin, thyroglobulin, calcitonin, thyroid transcription factor-1, alpha-smooth muscle actin, desmin, S-100 protein and CD117. Based on these findings, the two patients were diagnosed as having thyroid SFT. Neither local recurrence nor metastasis has been observed in 5 years in patient 1 or in 4 years in patient 2. Thyroid SFT is extremely rare, and only 20 cases have been reported in the English-language literature including hemangiopericytoma. Although recurrence or metastasis has not been described in any reported cases, the clinical behavior of SFT is still undetermined, therefore long-term follow up seems necessary at present.

Adult↗

PubMed2006

Feast/famine regulatory proteins (FFRPs): Escherichia coli Lrp, AsnC and related archaeal transcription factors.

Feast/famine regulatory proteins comprise a diverse family of transcription factors, which have been referred to in various individual identifications, including Escherichia coli leucine-responsive regulatory protein and asparagine synthase C gene product. A full length feast/famine regulatory protein consists of the N-terminal DNA-binding domain and the C-domain, which is involved in dimerization and further assembly, thereby producing, for example, a disc or a chromatin-like cylinder. Various ligands of the size of amino acids bind at the interface between feast/famine regulatory protein dimers, thereby altering their assembly forms. Also, the combination of feast/famine regulatory protein subunits forming the same assembly is altered. In this way, a small number of feast/famine regulatory proteins are able to regulate a large number of genes in response to various environmental changes. Because feast/famine regulatory proteins are shared by archaea and eubacteria, the genome-wide regulation by feast/famine regulatory proteins is traceable back to their common ancestor, being the prototype of highly differentiated transcription regulatory mechanisms found in organisms nowadays.

Archaeal Proteins↗

PubMed2005

Crystal structure and some properties of a major house dust mite allergen, Derf 2.

Pyroglyphid house dust mites are a major source of allergens in house dust. Mite allergens sensitize and induce asthma, rhinitis, and eczema in a large portion of patients with allergic diseases. Here, the crystal structure of a major mite allergen, Derf 2, derived from Dermatophagoides farinae was solved by single isomorphous replacement method with anomalous scattering (SIRAS) at 2.1A resolution. The present study also demonstrated that the conformation of the allergen was critical in the determination of Th1/Th2 shift based on physicochemical and immunological analyses. This indicates that rigidly folded and singly dispersed structure is essentially required for the generation of Th2 type cells by the allergen, while conformational variant protein leads to Th1 skewing, irrespective of the same amino acid sequence. This structure/function relationship may allow us to develop a novel strategy for hyposensitization therapy in patients with allergic diseases triggered by house dust mite allergens.

Animals↗

PubMed2005

Eustachian tube possesses immunological characteristics as a mucosal effector site and responds to P6 outer membrane protein of nontypeable Haemophilus influenzae.

The eustachian tube (ET) plays an important role in the pathogenesis of otitis media (OM). To better understand its biology and to develop a nasal vaccine for preventing OM, mucosal lymphocytes in the ET were analyzed, and the ET's immunological function was investigated. Mononuclear cells were isolated from murine ET, and lymphocyte subsets were analyzed by flow cytometry. Antibody-producing cells were determined by enzyme-linked immunospot assay. The expression of cytokine mRNA in ET CD4(+) T cells was determined by RT-PCR. Results in naive mice showed that the ET contained many immunocompetent cells, including a relative large number of IgA-producing cells and Th2 cytokine-expressing T cells. Next, we investigated antigen-specific immune responses in the ET. Mice were immunized intranasally with the P6 outer membrane of nontypeable Haemophilus influenzae (NTHi) and cholera toxin (CT), and P6-specific immune responses in the ET were examined. P6-specific IgA producing cells markedly increased in the ET. Moreover, in vitro stimulation with P6 of purified CD4(+) T cells from immunized mice resulted in the proliferation of CD4(+) T cells that expressed Th2 cytokine mRNA. These results indicate that the ET might be characterized as a mucosal effector site and that antigen-specific IgA and Th2 immune responses could be induced in the ET by intranasal immunization. These findings suggest that the ET might be a key immunological organ in the pathogenesis of OM, and in the development of a nasal vaccine.

Animals↗

PubMed2005

Phylogenetic characteristics, genomic heterogeneity and symptomatic variation of five closely related Japanese strains of Potato virus X.

To elucidate the genomic determinants of Potato virus X (PVX) strains, which cause diverse responses in host plants, we determined the complete genomic RNA sequences of four Japanese PVX strains: PVX-BS, -BH, -OG, and -TO. These four strains, plus the previously sequenced PVX-OS strain, differ in their pathogenicity in wild potato (Solanum demissum) and tobacco (Nicotiana tabacum cv. Samsun NN). The genomic sequences of these five PVX strains were highly homologous (i.e., the nucleotide sequence identity ranged from 95.4 to 98.5%). Phylogenetic analysis indicated that the Japanese PVX strains originated from an ancestral PVX strain in the European group, and that the virulence of these strains in both S. demissum and tobacco is not correlated with their phylogenetic relationships, suggesting that the pathogenicity of each strain in these host plants is determined by a relatively small number of nucleotides and can easily be altered independent of phylogenetic relationships. Particularly, OS, BH, and BS, which respectively produce markedly contrasting ringspot, mosaic, and asymptomatic infections in tobacco leaves, were the most closely related, suggesting that these three strains are an attractive model for analyzing the genetic determinants causing these symptoms. A possible correlation between the genomic and biological differences of these strains is discussed.

Amino Acid Sequence↗

PubMed2005

Dexamethasone inhibits tumor necrosis factor-alpha-induced cytokine secretion from spiral ligament fibrocytes.

To investigate the effect of proinflammatory cytokines on spiral ligament (SL) fibrocytes and regulation of cytokines by dexamethasone (Dex), in vitro studies were performed in murine secondary cell cultures. Cultured SL fibrocytes were stimulated with tumor necrosis factor-alpha (TNF-alpha), and the secretion of various mediators was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcribed-polymerase chain reaction (RT-PCR). After stimulation with TNF-alpha, levels of keratinocyte-derived cytokine (KC), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), interleukin-6 (IL-6) and soluble intercellular adhesion molecule-1 (sICAM-1) were elevated in the culture supernatant, and their corresponding messenger RNAs were detected in the cultured fibrocytes. When the cultures were incubated with both TNF-alpha and Dex, the levels of KC, MCP-1, MIP-2 and IL-6 were significantly lower than those in cultures treated with TNF-alpha alone. The data suggest that Dex suppresses the inflammatory response in SL fibrocytes. Given that SL fibrocytes play a role in cochlear fluid and ion homeostasis, glucocorticoids may suppress the cochlear malfunction caused by SL inflammation.

Animals↗

PubMed2005

Isoforms of dipeptidyl aminopeptidase IV from Pseudomonas sp. WO24: role of the signal sequence and overexpression in Escherichia coli.

The complete nucleotide sequence of dipeptidyl aminopeptidase IV (DAP IV) from Pseudomonas sp. WO24 was determined. Nucleotide sequence analysis revealed an open reading frame of 2238bp, which was assigned to dap4 by N-terminal and internal amino acid sequences previously reported. The predicted amino acid sequence of DAP IV contains a serine protease Gly-X-Ser-X-Gly-Gly consensus motif and displays extensive homology to DAP IVs and the homologous proteins from eukaryotes and bacteria, belonging to the prolyl oligopeptidase family S9. In Pseudomonas sp. WO24, DAP IV is expressed as 82 and 84-kDa isoforms, having two Met, Met-1 and Met-12, in its N-terminal sequence. Met-1 of DAP IV was mutated to Gly and Met-12 was mutated to Ile, and we overexpressed the two mutated genes in Escherichia coli and obtained the recombinant 82 and 84-kDa proteins from the periplasm and the cytoplasm, respectively, suggesting that the 82 and 84-kDa isoforms are derived from the same gene and localize to different compartments in the cell. We developed purification steps for activting a large amount of 84-kDa isoform protein that will be useful for producing protein for crystallographic studies.

Amino Acid Sequence↗

PubMed2005

A single amino acid residue of RNA-dependent RNA polymerase in the Potato virus X genome determines the symptoms in Nicotiana plants.

A Potato virus X (PVX) strain, PVX-OS, causes a necrotic mosaic in Nicotiana benthamiana and ring spot mosaic in N. tabacum cv. SamsunNN. By contrast, strain PVX-BS causes a mild mosaic in N. benthamiana and systemic asymptomatic infection in N. tabacum cv. SamsunNN. To investigate the viral determinant of this difference, we produced various infectious cDNA clones chimeric between these PVX genomes and clones with point mutations introduced by site-directed mutagenesis. Inoculation tests with these clones mapped the symptom determinant in Nicotiana plants to the 1422 amino acid residue in the region of the C-terminus of RNA-dependent RNA polymerase (RdRp). Western blot analysis and local lesion assay indicated that virus accumulation in the infected leaves was similar for these PVX strains, suggesting that the symptom difference was not due to virus accumulation.

Amino Acid Substitution↗

PubMed2005

Immunohistochemical detection of cervical lymph node micrometastases from T2N0 tongue cancer.

CONCLUSIONS: These results indicate that extensive, multiple cervical micrometastases occurred from an early stage in patients with T2N0 tongue cancer. The presence of micrometastases suggests the necessity of preventive neck dissection for Level I-IV nodes as a radical treatment. OBJECTIVE: Cervical lymph node metastases occur with a relatively high frequency in patients with T2N0 squamous cell carcinoma of the tongue, and control of the metastases greatly influences the prognosis of patients. In this study, micrometastases in the cervical lymph nodes were investigated to clarify the necessity and required extent of preventive neck dissection. MATERIAL AND METHODS: We investigated micrometastases in 24 subjects who had previously been diagnosed with T2N0 tongue cancer. We performed immunostaining with anti-cytokeratin antibody cocktail AE1/AE3 of sections of 401 paraffin-embedded lymph nodes obtained from these patients. RESULTS: Micrometastases were observed in 14 patients (58%) and were most abundant in Level II nodes (n=11; 46%). Micrometastases were observed in the Level IV nodes of 3 patients (13%), and upstaging to pN2b occurred in 7 patients (29%).

Adult↗

PubMed2005

Spontaneous temporomandibular joint herniation into the external auditory canal: a case report and review of the literature.

OBJECTIVES: Case report of a man presenting with spontaneous temporomandibular joint (TMJ) herniation into the external auditory canal (EAC). STUDY DESIGN: Case report and literature review. METHODS: A case report of a patient with spontaneous TMJ herniation into the EAC is presented. RESULTS: The patient was a 41-year-old man complaining of tinnitus in his right ear. Examination revealed that the anterior wall of the bony EAC moved backward when the patient's mouth was closed and forward when opened, causing the resultant discomfort. In this case, surgery was performed, resulting in a good outcome with no complications. Thirteen other cases of spontaneous TMJ herniation into the EAC were found in the literature. CONCLUSION: Few cases of spontaneous TMJ herniation into the EAC have been reported; however, if surgical treatment is desired, we should comply with the patient's request.

Adult↗