Biomedical subjects

Y Nagai

Publications and source records attributed to Y Nagai.

At least 37 records · Page 2Linked to original sources

PubMed2002

Ambulatory blood pressure monitoring in patients with spinocerebellar degeneration.

OBJECTIVES: The aim of this study was to demonstrate circadian blood pressure trends and to evaluate autonomic function in patients with spinocerebellar degeneration (SCD). MATERIALS AND METHODS: We performed 24-h ambulatory blood pressure monitoring (ABPM) on 10 patients from seven Japanese families with spinocerebellar ataxia type 6 (SCA6), 10 patients with idiopathic cerebellar ataxia (ICA), eight patients with multiple system atrophy (MSA) suffering from cerebellar MSA (MSA-C), and 12 age- and gender-matched normal subjects. We also evaluated autonomic function in these patients. RESULTS: Three SCA6 patients (30%), six ICA patients (60%), eight MSA-C patients (100%) and four normal subjects (33%) were non-dippers. The nocturnal reduction rate of blood pressure in MSA patients was significantly less than those in normal subjects, SCA6 patients and ICA patients. There were no abnormal findings in any patient with SCA6 in autonomic function tests. All dipper patients exhibited normal findings on autonomic function tests. This is the first report of ABPM in patients with SCD. CONCLUSIONS: Blunted reduction of nocturnal blood pressure may be associated with autonomic dysfunction in patients with SCD.

Aged↗

PubMed2002

Expression of the 67-kDa elastin receptor in perforating skin disorders.

BACKGROUND: Perforating skin dermatoses include elastosis perforans serpiginosa (EPS), reactive perforating collagenosis, Kyrle's disease and perforating folliculitis. In addition to these four diseases, an acquired form of perforating dermatosis associated with diabetes mellitus and/or chronic renal failure has been reported for which the term acquired perforating dermatosis (APD) was proposed. The molecular mechanism of transepidermal elimination of dermal components in perforating skin dermatoses remains unclear. We recently demonstrated that the 67-kDa elastin receptor can be detected in the epidermis eliminating altered elastic fibres in EPS, suggesting that the elastin-keratinocyte interaction may play a role in transepidermal elimination in EPS. OBJECTIVES: To determine whether the 67-kDa elastin receptor is involved in other perforating diseases. METHODS: Paraffin-embedded skin specimens from new cases of EPS (n = 2), APD (n = 15) and perforating granuloma annulare (PGA; n = 2) were studied immunohistochemically using a specific antibody to the 67-kDa elastin receptor. In one case of EPS, two different sites from a single lesion, a central atrophic area and a peripheral keratotic area, were studied. RESULTS: Expression of the elastin receptor was detected in the epidermis surrounding the elastic materials in both cases of EPS. The elastin receptor was not detected in the central inactive area, whereas it was expressed strongly in the peripheral keratotic active area. The elastin receptor was also detected in three of 15 cases of APD in which a few elastic fibres were found in the eliminated dermal materials. In one case of APD, the elastin receptor was not detected in spite of the presence of a few elastic fibres in the eliminated materials. The elastin receptor was not detected in either case of PGA. CONCLUSIONS: Expression of the elastin receptor in EPS was seen in both cases studied and was dependent on the stage of the lesion. Expression of the elastin receptor in APD appeared to be related to the amount of elastic fibres in the eliminated materials. Thus, expression of the elastin receptor in perforating skin disorders may depend on the stage of the lesion and/or the content of elastic fibres in the dermal materials being eliminated.

Adult↗

PubMed2002

Impact of maintenance chemotherapy on disease-free survival in patients with stage Ic and II epithelial ovarian cancer.

PURPOSE OF INVESTIGATION: To evaluate the impact on disease free survival (DFS) with maintenance chemotherapy following complete surgery and adjuvant chemotherapy in patients with stage Ic and II epithelial ovarian cancer by a retrospective study. METHODS: One hundred and forty patients with stage Ic and stage II epithelial ovarian cancer were classified into three groups according to the modality of maintenance chemotherapy (no therapy, oral or intravenous administration of anti-cancer drugs). DFS was compared among the three groups, and independent predictive factors for relapse were analyzed. RESULTS: There were no statistically significant differences in DFS among the three groups for either stage Ic or II cancers, stage Ic and stage II. Multivariate analysis revealed that independent predictive factors for relapse were stage II (p = 0.004) in all patients and less than three cycles of adjuvant chemotherapy in stage II patients (p = 0.015). CONCLUSION: Maintenance chemotherapy had no impact on DFS in patients with stage Ic or II epithelial ovarian cancer.

Adenocarcinoma, Clear Cell↗

PubMed2001

Identification of a new synaptic vesicle protein 2B mRNA transcript which is up-regulated in neurons by amyloid beta peptide fragment (1-42).

The treatment of Alzheimer's disease (AD) remains a major challenge because of the incomplete understanding of the triggering events that lead to the selective neurodegeneration characteristic of AD brains. Here we describe a new transcript of synaptic vesicle protein 2B (SV2Bb) mRNA that is up-regulated at mRNA level in neurons by amyloid beta peptide (Abeta) fragment (1-42). In comparison to SV2B this new mRNA encodes for the same protein but it has an elongated 3'-untranslated region (3'UTR) that contains several AU-rich (AUR) cis-acting elements which are probably involved in posttranscriptional regulating of SV2Bb translation. In conclusion, alteration of SV2B(b) expression appears to be involved in processes of neuronal degeneration.

3' Untranslated Regions↗

PubMed2001

Amino acid sequence requirements of peptides that inhibit polyglutamine-protein aggregation and cell death.

Proteins with expanded polyglutamine domains cause eight inherited neurodegenerative diseases including Huntington's disease. In a previous paper, we identified peptides that inhibit polyglutamine protein aggregation and cell death and now describe the amino acid sequence requirements necessary for these activities. The original 11 amino acid polyglutamine (Q) Binding Peptide 1(QBP1; SNWKWWPGIFD) can be shortened to 8 amino acids (WKWWPGIF) without loss of ability to inhibit polyglutamine aggregation. Three determinants are responsible for inhibition: a tryptophan-rich motif (WKWW), a spacer amino acid and the tripeptide GIF. GIF can be replaced by a repeat of the tryptophan-rich motif, but the spacer remains necessary. We also demonstrate concordance between peptide activity in the in vitro assay and a cellular assay of polyglutamine aggregation and cell death. Polyglutamine binding peptides targeted for intracellular delivery by fusion to TAT retain the ability to inhibit polyglutamine aggregation and cell death in transfected COS 7 cells.

Amino Acid Sequence↗

PubMed2001

Fermi surface of nanocrystalline embedded particles in materials: bcc Cu in Fe.

We report that a positron can act as a probe to directly reveal electronic structures of nanocrystalline embedded particles in materials. The Fermi surface (FS) of "bcc" Cu nanoparticles in an Fe matrix is observed as the first example. A two-dimensional angular correlation of the positron annihilation radiation (2D-ACAR) method is used to measure the momentum distribution which reflects the FS topology. The obtained 2D-ACAR spectra show strong and characteristic anisotropy associated with the necks of the FS around the [110] Brillouin zone boundaries of the bcc Cu, which are well reproduced by full-potential linearized argumented plane-wave calculations.

Journal Article↗

PubMed2001

In vivo gene transfer to cerebral white matter lesions with a recombinant adenovirus vector.

Ischemic white matter lesions have been reported in rats after bilateral common carotid ligation (BCAL). Previously, comparing normotensive rats (WKY) with spontaneously hypertensive rats (SHR), we too found that sustained moderate ischemia with spontaneous hypertension accelerated the formation of ischemic white matter lesions. In this study, we explored the feasibility of gene therapy for lesioned white matter by means of an adenovirus vector expressing a reporter gene, LacZ. Using sham-operated and hypoperfused SHR as well as sham-operated and hypoperfused WKY, we demonstrated that (i) adenovirus vectors could deliver a foreign gene into oligodendrocytes and astrocytes in the cerebral white matter; (ii) the transduction efficiency was most effective in SHR after BCAL; and (iii) the level of alpha(V)-integrin was significantly correlated with adenoviral transduction efficiency.

Adenoviridae↗

PubMed2001

Complete genome sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7.

The complete genomic sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7 which optimally grows at 80 degrees C, at low pH, and under aerobic conditions, has been determined by the whole genome shotgun method with slight modifications. The genomic size was 2,694,756 bp long and the G + C content was 32.8%. The following RNA-coding genes were identified: a single 16S-23S rRNA cluster, one 5S rRNA gene and 46 tRNA genes (including 24 intron-containing tRNA genes). The repetitive sequences identified were SR-type repetitive sequences, long dispersed-type repetitive sequences and Tn-like repetitive elements. The genome contained 2826 potential protein-coding regions (open reading frames, ORFs). By similarity search against public databases, 911 (32.2%) ORFs were related to functional assigned genes, 921 (32.6%) were related to conserved ORFs of unknown function, 145 (5.1%) contained some motifs, and remaining 849 (30.0%) did not show any significant similarity to the registered sequences. The ORFs with functional assignments included the candidate genes involved in sulfide metabolism, the TCA cycle and the respiratory chain. Sequence comparison provided evidence suggesting the integration of plasmid, rearrangement of genomic structure, and duplication of genomic regions that may be responsible for the larger genomic size of the S. tokodaii strain7 genome. The genome contained eukaryote-type genes which were not identified in other archaea and lacked the CCA sequence in the tRNA genes. The result suggests that this strain is closer to eukaryotes among the archaea strains so far sequenced. The data presented in this paper are also available on the internet homepage (http://www.bio.nite.go.jp/E-home/genome_list-e.html/).

Archaeal Proteins↗

PubMed2001

A family study of Tourette syndrome in Japan.

Although the mode of inheritance remains in doubt, twin and family studies conducted mostly in the United States and western Europe suggest that genetic factors play an important role in the transmission and expression of Tourette syndrome (TS). In an effort to evaluate population-based genetic differences, we generated risk estimates for first-degree relatives of TS probands in Japan using methods similar to those utilized in recent Western studies. The subjects were 52 TS probands seen at an outpatient clinic of Tokyo University Hospital and their 165 first-degree relatives. All probands and one or more first-degree relatives in each family were interviewed concerning the presence of tic and obsessive-compulsive symptoms by expert clinicians. The age-corrected rates of TS, chronic motor tics, obsessive-compulsive disorder, and subclinical obsessive-compulsive symptoms in the first-degree relatives were 2.0%, 12.0%, 1.6%, and 7.0%, respectively. Rates of TS and related disorders in Japan appear to be much lower than those in recent Western family studies. If replicated, these data suggest that there may be differences in the nature and frequency of vulnerable alleles for TS and related disorders in the Japanese compared to European populations.

Adolescent↗

PubMed2001

Synthesis and antimalarial activity of novel medium-sized 1,2,4,5-tetraoxacycloalkanes.

CsOH- or Ag(2)O-mediated cycloalkylation of (alkylidene)bisperoxides 3 and 1,n-dihaloalkanes (n = 3-8) provided the corresponding medium-sized 1,2,4,5-tetraoxacycloalkanes 4-8 in moderate yields. Subsequent evaluation of the antimalarial activity of the cyclic peroxides 4-8 in vitro and in vivo revealed that 1,2,6,7-tetraoxaspiro[7.11]nonadecane 4a has considerable potential as a new, inexpensive, and potent antimalarial drug.

Animals↗

PubMed2001

C-reactive protein is an independent predictor of the rate of increase in early carotid atherosclerosis.

BACKGROUND: An elevated plasma concentration of high-sensitivity C-reactive protein (hs-CRP) is a strong predictor of cardiovascular events. However, there have been no longitudinal studies of the relations between development of atherosclerotic lesions and hs-CRP concentrations. Furthermore, it remains unknown whether increased hs-CRP concentrations result in the development of atherosclerosis. METHODS AND RESULTS: The study included 179 outpatients 40 to 79 years of age who were treated at our institute for traditional risk factors for cardiovascular disease. The patients had no evidence of advanced carotid atherosclerosis at the time of baseline examination. Patients underwent repeated ultrasonographic evaluation of the carotid arteries for 35+/-10 months. Blood samples were collected for hs-CRP measurements. Based on focal intima-media thickening >/=1.1 mm representing plaque, plaque number (PN) and plaque score (PS; the sum of all plaque thicknesses) were calculated. The development of atherosclerosis was estimated by the formula Deltavalue/year=(last value-baseline value)/number of follow-up years. Multivariate linear regression analysis revealed that the log-transformed value for hs-CRP concentration was not related to baseline PN or PS but was related to DeltaPN/year and DeltaPS/year (beta=0.29 and 0.30; P<0.001 for both) independently of the effect of traditional risk factors. CONCLUSIONS: During the early stages of carotid atherosclerosis, the hs-CRP concentration is a marker of carotid atherosclerotic activity rather than extent of atherosclerosis.

Adult↗

PubMed2001

Stage-specific effects of a thiazolidinedione on proliferation, differentiation and PPARgamma mRNA expression in 3T3-L1 adipocytes.

To clarify the target phase of thiazolidinediones, which are ligands for peroxisome proliferator-activated receptor (PPAR)gamma, during adipocyte differentiation, the effects of a thiazolidinedione, pioglitazone, on every stage during the course of adipocyte differentiation were investigated. Pioglitazone did not affect the cellular protein content and [3H]thymidine incorporation into preconfluent 3T3-L1 preadipocytes. Induction of differentiation of confluent 3T3-L1 preadipocytes with insulin, dexamethasone and isomethylbutylxanthine for 48 h resulted in 30% inhibition of [3H]thymidine incorporation into the cells and 354% increase in cellular protein content. Pioglitazone at 1 microM accelerated the increase in cellular protein content by 33% and the inhibition in the [3H]thymidine incorporation by 12%. Pioglitazone, when added from the start of the induction stage, dose-dependently enhanced cellular triglyceride accumulation, and both basal and insulin-stimulated glucose transporting activity producing only a slight increase in the ratio of insulin stimulation to basal glucose transporting activity. In mature adipocytes, however, pioglitazone did not enhance either of the transporting activities. PPARgamma messenger RNA (mRNA) levels estimated by a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) increased during the course of adipocyte differentiation. Although pioglitazone dose-dependently up-regulated PPARgamma mRNA levels in postconfluent preadipocytes without induction, it down-regulated them in mature adipocytes. Thus, a PPARgamma agonist, pioglitazone, arrested the growth, and increased protein content and PPARgamma mRNA levels in postconfluent preadipocytes, followed by commitment and hypertrophy of 3T3-L1 cells without changing insulin sensitivity, whereas it failed to stimulate glucose transporting activities and down-regulated PPARgamma mRNA expression in mature adipocytes.

3T3 Cells↗

PubMed2001

Up-regulation of calcineurin Abeta mRNA in the Alzheimer's disease brain: assessment by cDNA microarray.

Recent advances in cDNA microarray technology have made it possible to analyze expression of more than 8000 genes. Using this technology, gene expression in the hippocampus containing neurofibrillary tangle-associated lesions from an Alzheimer's disease (AD) patient was compared with expression in the parietal cortex from the same patient that lacked these lesions. We also compared gene expression using a control brain. The top 20 named genes significantly up-regulated or down-regulated only in the AD brain were determined. The most up-regulated gene proved to be calcineurin Abeta mRNA (CAbeta). In situ hybridization histochemistry revealed that CAbeta was significantly up-regulated in pyramidal neurons of the hippocampus in the AD brain. RT-PCR analysis revealed that CAbeta was up-regulated in the hippocampus from two out of three AD brains while there were no changes in three control brains. Our study suggests that CAbeta may play a crucial role in the pathophysiological mechanisms in AD.

Aged↗

PubMed2001

Phosphatidylserine-specific phospholipase A1 stimulates histamine release from rat peritoneal mast cells through production of 2-acyl-1-lysophosphatidylserine.

Lysophosphatidylserine (1-acyl-2-lyso-PS) has been shown to stimulate histamine release from rat peritoneal mast cells (RPMC) triggered by FcepsilonRI (high affinity receptor for IgE) cross-linking, although the precise mechanism of lyso-PS production has been obscure. In the present study we show that phosphatidylserine-specific phospholipase A(1), PS-PLA(1), stimulates histamine release from RPMC through production of 2-acyl-1-lyso-PS in the presence of FcepsilonRI cross-linker. The potency of 2-acyl-1-lyso-PS was almost equal to that of 1-acyl-2-lyso-PS. A catalytically inactive PS-PLA(1), in which an active serine residue (Ser(166)) was replaced with an alanine residue did not show such activity. sPLA(2)-IIA, another secretory PLA(2) that is capable of producing lyso-PS in vitro, was also a poor histamine inducer against RPMC. PS-PLA(1) significantly stimulated histamine release from crude RPMC, indicating that lyso-PS is mainly derived from cells other than mast cells. In agreement with this phenomenon, the enzyme stimulated the histamine release more efficiently when RPMC were mixed with apoptotic Jurkat cells. Under these conditions, lyso-PS with unsaturated fatty acid was released from the apoptotic cells treated with PS-PLA(1). Finally, heparin, which has affinity for PS-PLA(1), completely blocked the stimulatory effect of the enzyme. In conclusion, PS-PLA(1) may bind to heparan sulfate proteoglycan, efficiently hydrolyze PS appearing on plasma membranes of apoptotic cells, and stimulate mast cell activation mediated by 2-acyl-1-lyso-PS.

Animals↗

PubMed2001

Isolation and characterization of a full-length molecular DNA clone of Ghanaian HIV type 1 intersubtype A/G recombinant CRF02_AG, which is replication competent in a restricted host range.

We have isolated a replication-competent, full-length molecular clone of HIV-1 CRF02_AG, designated p97GH-AG1, by reconstituting two separately amplified genomic regions of an HIV-1 provirus of a 1997 Ghanaian isolate. The phylogenetic and recombination breakpoint analyses revealed that 97GH-AG1 had an A/G recombinant structure similar to that of prototype Nigerian isolate IbNG. The 17-nucleotide insertion downstream of the primer-binding site appeared to be a common sequence signature specific to most CRF02_AG strains, including 97GH-AG1. 97GH-AG1 showed an R5 phenotype and exerted productive infection in both HOS and NP2 cell infectivity assays, whereas it failed to show a detectable level of progeny production in peripheral blood mononuclear cells (PBMCs). The data may suggest the presence of unknown determinant(s) that dictate efficient replication in PBMCs, but that are not required for replication in immortalized cell lines.

Amino Acid Sequence↗

PubMed2001

Whole genome sequencing of meticillin-resistant Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever, and has acquired resistance to practically all antibiotics. Whole genome analysis is a necessary step towards future development of countermeasures against this organism. METHODS: Whole genome sequences of two related S aureus strains (N315 and Mu50) were determined by shot-gun random sequencing. N315 is a meticillin-resistant S aureus (MRSA) strain isolated in 1982, and Mu50 is an MRSA strain with vancomycin resistance isolated in 1997. The open reading frames were identified by use of GAMBLER and GLIMMER programs, and annotation of each was done with a BLAST homology search, motif analysis, and protein localisation prediction. FINDINGS: The Staphylococcus genome was composed of a complex mixture of genes, many of which seem to have been acquired by lateral gene transfer. Most of the antibiotic resistance genes were carried either by plasmids or by mobile genetic elements including a unique resistance island. Three classes of new pathogenicity islands were identified in the genome: a toxic-shock-syndrome toxin island family, exotoxin islands, and enterotoxin islands. In the latter two pathogenicity islands, clusters of exotoxin and enterotoxin genes were found closely linked with other gene clusters encoding putative pathogenic factors. The analysis also identified 70 candidates for new virulence factors. INTERPRETATION: The remarkable ability of S aureus to acquire useful genes from various organisms was revealed through the observation of genome complexity and evidence of lateral gene transfer. Repeated duplication of genes encoding superantigens explains why S aureus is capable of infecting humans of diverse genetic backgrounds, eliciting severe immune reactions. Investigation of many newly identified gene products, including the 70 putative virulence factors, will greatly improve our understanding of the biology of staphylococci and the processes of infectious diseases caused by S aureus.

Animals↗

PubMed2001

Presence of multiple HIV type 1 subtypes among mothers and children in Japan.

We collected blood samples from 70 HIV-1-infected pregnant women and 76 babies born to HIV-1-infected women in Japan, from 1989 to 1999. To analyze the genetic diversity of HIV-1 among mothers and children, we sequenced the C2-V3 regions of HIV-1 gp120. Phylogenetic tree analysis of these regions revealed that multiple HIV-1 subtypes, A, B, D, E, and G, were circulating among mothers and children in Japan. Thus, the genetic heterogeneity of HIV-1 among mothers and children in Japan is steadily increasing, although the number of cases remains small. Perhaps the longest term survivor, an 11-year-old child with a vertical HIV-1 subtype G infection in Japan, is one of our subjects.

Amino Acid Sequence↗

PubMed2001

Homocysteine inhibits angiogenesis in vitro and in vivo.

Homocysteine has been reported to inhibit endothelial cell proliferation, which is closely related to angiogenesis. However, the relationship between homocysteine and angiogenesis is unknown. To clarify whether homocysteine would inhibit angiogenesis in vitro and in vivo, we examined the effect of homocysteine on tube formation by bovine aortic endothelial cells (BAECs) and by human microvessel endothelial cell-1 (HMEC-1) in vitro, and on angiogenesis in vivo using the chorioallantoic membrane (CAM) assay, as well as on BAEC proliferation and migration. Homocysteine, but not cysteine, inhibited BAEC proliferation, migration, and tube formation in a dose-dependent manner at concentrations from 0 to 10 mM. Homocysteine also inhibited tube formation by HMEC-1s. In these assay, 50% inhibition was induced by about 1 mM homocysteine. In the in vivo CAM assay, 0, 10, 100, 500, and 1000 microgram homocysteine induced an avascular zone by 0, 0, 16.7, 53.3 and 76.5%, respectively, also showing a dose-dependent effect. It was suggested that homocysteine inhibited angiogenesis by preventing proliferation and migration of endothelial cells.

Animals↗