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Biomedical subjects

M Sekine

Publications and source records attributed to M Sekine.

At least 37 records · Page 2Linked to original sources
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

Mechanosensitive afferent units in the lumbar posterior longitudinal ligament.

STUDY DESIGN: The mechanosensitive afferent units in the lumbar posterior longitudinal ligament were investigated in an animal model using an electrophysiologic technique. OBJECTIVES: The objectives of this study were to identify the mechanosensitive receptive fields in the lumbar posterior longitudinal ligament and to investigate their distribution and characteristics. SUMMARY OF BACKGROUND DATA: The lumbar posterior longitudinal ligament has a nerve network originating from the sinuvertebral nerve. These fibers are thin, and most of their terminals are free nerve endings. Some immunohistochemical studies have indicated that they are immunoreactive to calcitonin gene-related peptide and/or substance P, suggesting a nociceptive function. Most of these studies investigated morphologic aspects, and there have been few studies employing electrophysiologic techniques to examine mechanosensitive units. METHODS: We used 13 adult cats. They were anesthetized and then laminectomy was performed. The L5 and L6 dorsal rootlets were draped over a recording electrode. To investigate the receptive fields in the posterior longitudinal ligament, afferent impulses were evoked by mechanical stimulation with a glass probe. When the receptive fields were located, they were stimulated electrically to obtain conduction velocity and were stimulated with a set of 17 nylon filaments to determine their mechanical thresholds. RESULTS: Thirteen units were identified in the lumbar posterior longitudinal ligament. The majority of the units were located around the intervertebral disc level of the posterior longitudinal ligament. The mean mechanical threshold was 47.04 +/- 15.25 g. According to the conduction velocities of the units, 12 units were classified into Group III (0.5-2.5 m/sec) and one unit into Group IV (2.5-20 m/sec). CONCLUSION: Mechanosensitive units classified into Group III or Group IV and with a high mechanical threshold (>7.0 g) were thought to act as nociceptive units. All units identified in this study satisfied these criteria. Our result suggests that afferent fibers from the lumbar posterior longitudinal ligament have a principally nociceptive function.

Afferent Pathways↗
PubMed2001

Localization of a novel susceptibility gene for familial ovarian cancer to chromosome 3p22-p25.

We performed genome-wide linkage analysis in 58 patients and nine unaffected members among 28 families with no mutation in BRCA1 or BRCA2, employing a set of 410 microsatellite markers. We initially screened the whole genome, including the X chromosome, by a non-parametric method using the GENEHUNTER program. As a result, chromosome 3p22-p25 showed a suggestive score for linkage [LOD = 3.49 and non-parametric LOD (NPL) = 2.77 at D3S3611] based on a multipoint analysis. Additionally, based on a two-point analysis using dense markers, this 3p22-p25 region showed a P-value < 0.05 at 10 markers and there is suggestive evidence for linkage at two markers within approximately 19 cM (NPL = 2.60 and 2.49 at D3S1597 and D3S3611, respectively). To explore whether the candidate gene in this 3p22-p25 region contributed to carcinogenesis of familial ovarian cancer in a similar fashion to the tumor suppressor gene, we performed loss of heterozygosity (LOH) analysis. It was observed that the frequency of LOH at four markers in this region was >50% only in tumor tissues from patients with no mutation in BRCA1 or BRCA2, not in those with a BRCA1 mutation.

Adult↗
PubMed2001

Traumatic paraplegia in snowboarders.

STUDY DESIGN: Patients with traumatic paraplegia resulting from snowboarding accidents were reviewed. OBJECTIVE: To understand the clinical features and mechanisms of paraplegic snowboarding injuries. SUMMARY OF BACKGROUND DATA: The recent explosion in the popularity of snowboarding has resulted in dramatically increased numbers of snowboarding injuries. However, little information is available as to the types and mechanisms of snowboard-related spinal injuries and their neurologic involvement. METHODS: The subjects of this study were six male patients, with an average age of 23.7 years, referred to the authors' institution for neurologic deficits associated with spinal injuries between January 1996 and March 1999. The clinical features of these patients were reviewed with respect to the mechanism of the injury, fracture pattern, neurologic status, treatment, and clinical outcome. The mean follow-up period was 23.7 months. RESULTS: The six snowboarders with traumatic paraplegia constituted a very homogenous group with the following features: They were all young men between the ages of 23 and 25 years. All the injuries had occurred at the vertebral junctions. The primary mechanism of the fractures was a backward fall from an intentional jump. The fracture patterns were of the flexion-distraction type. These homologous features suggest that this snowboarding group is at high risk for severe spinal injury. CONCLUSION: The high risk of traumatic paraplegia for a group within the snowboarding population requires the development and provision of injury prevention strategies specific to this group.

Adult↗
PubMed2001

Occurrence of D-Amino Acids and a pyridoxal 5'-phosphate-dependent aspartate racemase in the acidothermophilic archaeon, Thermoplasma acidophilum.

Free D-amino acid content in some archaea was investigated and D-forms of several amino acids were found in them. In the acidothermophilic archaeon, Thermoplasma acidophilum, the proportion of D-aspartate (D-Asp) to total Asp was as high as 39.7%. Crude extracts of Thermoplasma acidophilum had Asp-specific racemase activity that was pyridoxal 5'-phosphate (PLP)-dependent. The relative insensitivity to a SH-modifying reagent distinguished this activity from those of the PLP-independent Asp racemases found in other hyperthermophilic archaea (Matsumoto, M., et al., J. Bacteriol. 181, 6560-6563 1999). Thus, high levels of d-Asp should be produced by a new type(s) of Asp-specific racemase in Thermoplasma acidophilum, although the function of d-Asp in this archaeon remains unknown.

Alanine↗
PubMed2001

A model for membrane bioreactor process based on the concept of formation and degradation of soluble microbial products.

A mathematical model of soluble microbial products (SMPs) formation-degradation was established based on the activated sludge model no. 1 and was applied to the membrane bioreactor process with high concentration of activated sludge under intermittent aerobic operational condition. The simulation results were in good agreement with the experimental data which indicated that the coefficients used in the model could successfully describe the treatment performance. The most advantage of this modified model over the conventional one was that the significant importance of SMP existence was demonstrated and the model provided an reasonable comprehension for SMP concept. The present study demonstrated that SMPs contributed most to the organic matter in the effluent, and the results coincided well with the observations of many other researchers.

Biodegradation, Environmental↗
PubMed2001

New halogenated marine prostanoids with cytotoxic activity from the Okinawan soft coral Clavularia viridis.

Five new halogenated prostanoids 1-4 and 6 were isolated from the Okinawan soft coral Clavularia viridis. The gross structure of 1 was elucidated mainly on the basis of NMR spectral data. The relative and absolute configurations were determined by analysis of NOESY and CD data, chemical conversion, and the modified Mosher's method. The structures of 2-4 and 6 were deduced by comparison of their spectral data with those of 1. Compound 1 demonstrated cytotoxic activity.

Algorithms↗
PubMed2001

Regulation of mouse kidney tubular epithelial cell-specific expression of core 2 GlcNAc transferase.

A mouse gene, Gsl5, controls the expression of Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-6(Galbeta1-3)Gb4Cer and its precursor glycolipids in the kidney by regulating transcription of beta-1,6-GlcNAc transferase. Here we report that Gsl5 controls the expression of the core 2 structure [GlcNAcbeta1-6(Galbeta1-3)GalNAcalpha1-Ser/Thr] of glycoproteins as well as the glycolipid, GlcNAcbeta1-6(Galbeta1-3)GalNAcbeta1-3Galalpha1-4Galbeta1-4Glcbeta1-ceramide. Immunohistochemical studies using an anti-(core 2-Lex) monoclonal antibody demonstrated that lysosome-like vesicles of proximal tubule cells were clearly stained in a Gsl5 wild type mouse, but not in a Gsl5 mutant strain of mice. Western blotting of microsomal fractions of kidney tissue with the same antibody confirmed the histological findings. In situ hybridization with an antisense probe to the kidney-specific mRNA demonstrated that the mRNA is localized at proximal tubule-cells in the cortex adjacent to the medulla, but not detected in glomeruli nor in collecting duct cells in the medulla. The results obtained by immunohistological staining and in situ hybridyzation are compatible and lead to the conclusion that the kidney specific mRNA is expressed in a proximal tubular cell specific manner and produces core 2 GlcNAc transferase responsible for the production of glycoproteins localized at vesicles in the proximal tubular cells. Glycosylation regulated by Gsl5 gene may modify functions of membrane glycoproteins in proximal tubular cells.

Animals↗
PubMed2001

Triglyceride-rich lipoprotein cholesterol exceeds low-density lipoprotein cholesterol in hypertriglyceridemia patients.

The atherogenicity of triglyceride-rich lipoprotein has been revealed. This study was performed to explore the clinical importance of triglyceride-rich lipoprotein by measuring its cholesterol content and comparing it with other lipoprotein fractions. Blood samples were obtained from 103 patients whose fasting plasma triglyceride concentration exceeded 300 mg/dl. The cholesterol monitor using the technique of high-performance liquid chromatography was used for the measurement of their plasma cholesterol concentrations and the determination of cholesterol distribution among lipoprotein fractions. This monitor showed 4 peaks: large-triglyceride-rich lipoprotein, small-triglyceride-rich lipoprotein, low-density lipoprotein, and high-density lipoprotein. Total cholesterol increased with increasing triglyceride. The increment of total cholesterol was nearly equal to that of small-triglyceride-rich lipoprotein cholesterol. Small-triglyceride-rich lipoprotein cholesterol exceeded low-density lipoprotein cholesterol where plasma triglyceride concentration was over 500 mg/dl. In conclusion, triglyceride-rich lipoprotein may be clinically important for hypertriglyceridemic patients as a source of cholesteryl ester in arteriosclerotic plaques, and increased triglyceride-rich lipoprotein cholesterol may be used as a basis for hypertriglyceridemia atherogenicity. Our study suggests that hypertriglyceridemia should be treated to prevent arteriosclerotic disease.

Apolipoproteins E↗
PubMed2001

Effect of enforced aeration on in-vessel food waste composting.

A laboratory composting was conducted to determine the effect of the continuously enforced aeration on the composting performance. The mixture of dog food, excess sludge, and woodchip was used as raw composting materials. The temperature changes in the decomposition process, and pH, weight loss, ash, and extract composition from the final product after 17 days composting were investigated. The results demonstrated that flow rate of enforced aeration indeed influenced the composting performance. Composting under 0.05-0.1 1 min(-1) condition seemed better than that under 0.2-0.41 min(-1) condition. Higher flow rate of air not only cooled the composting mixture significantly, further adversely affected temperature rise, but also evaporated moisture mostly. Thermophilic composting can occur under 0.05-0.11 min(-1) air flow rate condition, while composting in cases of 0.2-0.4 l min(-1) air flow rate mainly resulted in a mesophilic process. Microbial activity was considered to be significantly inhibited at 0.4 1 min(-1) air flow rate condition based on the analyses of total organic carbon and volatile fatty acids from water extraction of composting products.

Air Movements↗
PubMed2001

Synthesis and properties of a new oligonucleotide analogue containing an internucleotide squaryl amide linkage.

We report here the synthesis and properties of a new oligonucleotide analogue (5'-CGCATsqTAGCC-3') containing a squaryl group in place of the fifth phosphate group from the 5'-terminus. The modified thymidine dimer building unit was synthesized by use of 5'-amino-5'-deoxythymidine and a 3'-amino-3'-deoxythymidine derivative. This building unit was phosphitylated and incorporated into the oligonucleotide by the phosphoramidite method. The hybridization ability of this modified oligomer with the complementary oligonucleotide was studied in detail by using Tm experiments and CD spectroscopy as well as computer simulations. These results suggest that this modified duplex has a unique bend conformation.

Amides↗
PubMed2001

Binding specificities of the mismatch binding protein, MutS, to oligonucleotides containing modified bases.

We have studied the effects of DNA mismatch repair on mutagenesis induced by nucleoside analogs. Among them, the mutagenic action of 3,4-dihydro-6H,8H-pyrimido[4,5-c][1,2]oxazin-7-one 2'-deoxyriboside (dP) showed high susceptibility to the mismatch repair system, while mutagenesis by N4-aminocytidine and N4-hydroxycytidine was only weakly affected. 2-Aminopurine mutagenesis showed intermediate susceptibility. MutS protein specifically bound to an oligonucleotide duplex containing a dP-dG pair, while the dP-dA pair was bound only weakly. The binding to the dP-dG pair was as strong as binding to a dA-dC mismatch. These specific binding properties can explain the effective avoidance of dP-induced mutagenesis by the mismatch repair system. We have also studied the effects of the repair system on mutagenesis induced by methylating and ethylating agents.

2-Aminopurine↗
PubMed2001

Ab initio molecular orbital evaluation of the hydrogen bond energy of base pairs formed between substituted 1-methylcytosine derivatives and 9-methylguanine.

The substitution effect on hydrogen bond energy of the Watson-Crick type base pair between 9-methylguanine (G) and chemically modified 1-methylcytosine (CX) derivatives was evaluated by ab initio molecular orbital theory. A remarkable trend was observed in the substitution effect of the hydrogen bond stability: Cytosine derivatives possessing an electron-donating group form stable base pairs with guanine. However, both the hydrogen bond distance and the charge distribution were not good indexes for the hydrogen bond status in CX-G base pairing.

Base Pairing↗
PubMed2001

Cell cycle regulation of cyclin-dependent kinases in tobacco cultivar Bright Yellow-2 cells.

Plants possess two major classes of cyclin-dependent kinases (CDK) with cyclin-binding motifs PSTAIRE (CDK-a) and PPTA/TLRE (CDK-b). Tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells are the most highly synchronizable plant culture, but no detailed analysis of CDK activities has been reported in this system. Here we describe isolation of new PPTALRE CDKs (Nicta;CdkB1) from Bright Yellow-2 cells and present detailed analysis of the mRNA, protein and kinase activity levels of CdkB1, and the PSTAIRE CDKA during the growth and cell cycles. CdkA and CdkB1 transcripts are more abundant in exponential than in stationary phase cells, but the two genes show strikingly different regulation during the cell cycle. CdkA mRNA and protein accumulate during G1 in cells re-entering the cell cycle, and immunoprecipitated histone H1 kinase activity increases at the G1/S boundary. Aphidicolin synchronized cells show the highest CDKA-associated histone H1 kinase activity during S-G2 phases, although CdkA mRNA and protein levels are not significantly regulated. In contrast, CdkB1 transcripts are present at very low levels until S phase and CDKB1 protein and kinase activity is almost undetectable in G1. CdkB1 mRNA accumulates through S until M phase and its associated kinase activity peaks at the G2/M boundary, confirming that transcription of PPTALRE CDKs is cell cycle regulated. We suggest that CDKA kinase activity likely plays roles at the G1/S phase boundary, during S phase, and at the G2/M phase transition, and that CDKB1 kinase activity is present only at G2/M.

CDC2 Protein Kinase↗
PubMed2001

The relationship between new stroke onset and serum thiocyanate as an indicator to cigarette smoking.

The case subjects were 67 stroke patients (27 males and 40 females, mean age 65.7+/-7.1), who suffered from stroke attack and had participated in annual medical check-up between 1987 and 1988 at Oyabe Public Health Center. The controls, which were adjusted for sex, age and blood pressure level with the case subjects, were selected from participants attending their annual medical check-up in 1987-1988. The serum thiocyanate level of case subjects were significantly higher than that of controls (p<0.05). The usefulness of measurement of serum thiocyanate level as an indicator of smoking status was assessed by using multiple logistic regression analysis adjusting for body mass index, mean blood pressure, and serum cholesterol was found. An odds ratio of 3.00 (95% confidence interval: 1.06-8.48, p<0.05) in cerebral infarction. It is considered that serum thiocyanate may be useful as an indicator of smoking status to assess the relationship with stroke onset, especially for cerebral infarction.

Age Distribution↗
PubMed2001

Mutational analysis of BRCA1 and BRCA2 and clinicopathologic analysis of ovarian cancer in 82 ovarian cancer families: two common founder mutations of BRCA1 in Japanese population.

We analyzed genetic alterations in BRCA1 and BRCA2 genes among 82 ovarian cancer families in Japan. The clinical characteristics of BRCA-associated ovarian cancer patients were compared with cases carrying no mutations as well as with population controls. Using a direct sequencing method, 45 of the 82 ovarian cancer families were found to carry BRCA1 or BRCA2 germ-line mutations (40 with BRCA1 and 5 with BRCA2). In 24 independent mutations of BRCA1, 5 recurrent mutations were found and 2 of them, the L63X and Q934X mutations, were detected in seven and eight independent families, respectively. In addition, 16 mutations of BRCA1 and 3 mutations of BRCA2 have never been described previously. In consideration of clinicopathological features, there was a significantly higher proportion of tumors with serous adenocarcinoma and of cases of advanced stages in the BRCA1 or BRCA2 cases than in those of the controls. On the other hand, there were no differences of mean age at diagnosis between patients with BRCA1 or BRCA2 mutation and those of the controls. Our results indicate that the features of BRCA-associated ovarian cancer in Japan appear to be similar to those in Western countries, and the L63X and Q934X mutations of BRCA1 appear to be common founder mutations unique to the Japanese population.

Adolescent↗