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Biomedical subjects

N Takada

Publications and source records attributed to N Takada.

At least 55 records · Page 3Linked to original sources
PubMed2000

Structural variation in the 16S-23S rRNA intergenic spacers of Vibrio parahaemolyticus.

The 16S-23S rRNA intergenic spacers (IGS) of Vibrio parahaemolyticus were PCR-amplified and cloned with pT7Blue T vector. A total of six clones were isolated dependent on size difference. The clones were different with respect to both the number and the composition of the tRNA genes included, and were designated IGS-0, IGS-E, IGS-IA, IGS-AE, IGS-EKV and IGS-EKAV. IGS-EKAV included the cluster of tRNA(Glu)-tRNA(Lys)-tRNA(Ala)-tRNA(Val); IGS-EKV, tRNA(Glu)-tRNA(Lys)-tRNA(Val); IGS-AE, tRNA(Ala)-tRNA(Glu); IGS-IA, tRNA(Ile)-tRNA(Ala); and IGS-E, tRNA(Glu). IGS-0 had no tRNA gene. Some similarities were found in the nucleotide sequence of the non-coding regions flanked by the tRNA genes. The structure difference found in the spacers is meaningful for elucidating the evolutionary line of each ribosomal RNA operon and the profile is applicable as a molecular marker of the bacterium.

Cloning, Molecular↗
PubMed2000

Actions of brain-derived neurotrophic factor on evoked and spontaneous EPSCs dissociate with maturation of neurones cultured from rat visual cortex.

To address the question of whether brain-derived neurotrophic factor (BDNF) directly enhances excitatory synaptic transmission, we recorded excitatory postsynaptic currents (EPSCs) from solitary neurones cultured on glial microislands for 7-38 days, and observed changes in EPSCs after the application of BDNF. In this preparation the possible action of BDNF on GABAergic inhibition was not involved, and evoked and spontaneous (miniature) EPSCs were derived from the same group of synapses (autapses). The application of BDNF at a concentration of 200 ng ml-1 rapidly enhanced the frequency of miniature EPSCs (mEPSCs) in almost all the neurones tested. On the other hand, the amplitude of mEPSCs did not change at all, suggesting that the site of BDNF action is presynaptic. In contrast to the enhanced frequency of mEPSCs, evoked EPSCs were not potentiated in 61 % of the cells tested. Most of these BDNF-insensitive EPSCs had a peak amplitude larger than 1 nA, while most of the other BDNF-sensitive EPSCs had a smaller amplitude. The former EPSCs had smaller coefficients of variation (CVs) of amplitude, while the latter had larger CVs, suggesting the possibility that the presynaptic release probability for the former groups of EPSCs might have beeen saturated so that the BDNF action was occluded. To test this possibility we applied a low Ca2+ solution to 17 cells and reduced the amplitude of their evoked EPSCs to less than or near to 1 nA. It was found, however, that BDNF did not enhance these EPSCs. Rather, evoked EPSCs of almost all the cells cultured for less than 15 days were enhanced by BDNF, while those of most of the cells cultured for longer than 16 days were not enhanced. These results suggest that BDNF enhances transmitter release from presynaptic sites through its action on the release machinery, which can be differentiated into a BDNF-insensitive form for evoked release and a BDNF-sensitive form for spontaneous release with maturation of synapses.

Animals↗
PubMed2000

High expression of Survivin, mapped to 17q25, is significantly associated with poor prognostic factors and promotes cell survival in human neuroblastoma.

Survivin (SVV) is a family member of inhibitor of apoptosis proteins (IAPs) and its expression is cell cycle regulated. The gene is mapped to chromosome 17q25, the region of which is frequently gained in advanced stages of neuroblastoma (NBL). However, the role of SVV in NBL is poorly understood. Here we studied the clinical and biological role of SVV in NBL. A 1.9 kb SVV transcript was expressed in all of 9 NBL cell lines at higher levels than those in adult cancer cell lines. In 34 primary NBLs, high levels of SVV expression was significantly associated with age greater than 12 months (two sample t-test: P= 0.0003), advanced stages (P = 0.0136), sporadic tumors (P= 0.0027) and low levels of TrkA expression (P = 0.0030). In NBL cell lines, SVV mRNA expression was dramatically down-regulated in CHP134 and IMR32 cells undergoing apoptosis after treatment with all-trans retinoic acid (RA) or serum deprivation. It was only moderately decreased in cells (SH-SY5Y and CHP901) undergoing RA-induced differentiation. On the other hand, in proliferating NBL cells or RA-treated SK-N-AS line which is refractory to RA, the SVV mRNA remained at steady state levels or rather up-regulated. Furthermore, transfection of SVV into CHP134 cells induced remarkable inhibition of the RA-induced apoptosis. Collectively, our results suggest that high expression of SVV is a strong prognostic indicator for the advanced stage neuroblastomas, and that it could be one of the candidate genes for the 17q gain.

Apoptosis↗
PubMed2000

Hunting the subset-specific genes of neuroblastoma: expression profiling and differential screening of the full-length-enriched oligo-capping cDNA libraries.

BACKGROUND: Neuroblastoma (NBL) has a distinct nature in different prognostic subgroups. PROCEDURE: To understand the molecular mechanism of NBL's genesis and biology as well as that of the neural crest development, we constructed full-length-enriched cDNA libraries by an oligo-capping method from two different subsets of primary NBL, one with favorable biology and the other with MYCN amplification. RESULTS: Sequencing analysis of these libraries revealed that the expression profile was markedly different between both subsets. To identify the genes differentially expressed between the subsets, semi-quantitative RT-PCR analyses are proceeding. CONCLUSION: So far, 54 transcripts have been found to be expressed at high levels in favorable NBLs, and significantly at low levels in unfavorable NBLs.

Gene Expression Regulation, Neoplastic↗
PubMed2000

Association between favorable neuroblastoma and high expression of the novel metalloproteinase gene, nbla3145/XCE, cloned by differential screening of the full-length-enriched oligo-capping neuroblastoma cDNA libraries.

BACKGROUND: The biology of neuroblastoma (NBL) is at least partly regulated by neurotrophic factors and their receptors. PROCEDURE: To identify novel NBL-related genes that affect growth, differentiation, and programmed cell death of the tumor, we constructed full-length-enriched cDNA libraries by oligo-capping method. RESULTS: Semi-quantitative and quantitative real-time RT-PCR showed that the nbla3145 gene was significantly highly expressed in favorable subset of NBL. The nucleo-tide sequence of nbla3145 revealed that it was a novel member of metalloproteinase, endothelin-converting enzyme, and was the same gene recently reported as XCE. We also cloned nbla3145beta which was a novel truncated form of nbla3145 (or nbla3145alpha). CONCLUSIONS: Our results suggested that nbla3145/XCE plays an important role in regulating growth and differentiation of NBL.

Gene Expression Regulation, Neoplastic↗
PubMed2000

NFBD1/KIAA0170 is a novel nuclear transcriptional transactivator with BRCT domain.

The BRCT (BRCA1 C-terminus) superfamily includes a large number of nuclear proteins closely involved in DNA repair, recombination, and cell-cycle control. The human cDNA clone NFBD1 (previously designated KIAA0170) encodes a novel protein (2089 amino acids in length; calculated molecular mass 226,440 D) with possible BRCT domains at its carboxy terminus (amino acid residues 1894-2089). This gene product has been described as one of the BRCT superfamily proteins. However, its biological significance has been unclarified. Expression of green fluorescent protein (GFP)-tagged full-length NFBD1 or a series of deletion mutants indicated that NFBD1 was localized to the nucleus in various mammalian cells, and a 197-amino acid segment near the amino terminus (amino acid residues 142-338) contained a nuclear targeting signal. In vitro DNA-binding experiments showed that the highly basic region of NFBD1 (amino acid residues 1841-1893) possessed DNA-binding activity. The region encoding amino acids 508-995 of NFBD1 fused inframe with GAL4 DNA-binding domain activated transcription in both yeast and mammalian cells, while the possible BRCT domains of NFBD1 failed to induce transcription in mammalian cells. Overexpression of antisense NFBD1 RNA in a p53-deficient human osteogenic sarcoma cell line (SAOS-2) resulted in remarkable suppression of SAOS-2 colony formation. These results suggest that NFBD1 is a nuclear transcriptional transactivator with possible BRCT domains and may contribute to cell growth control.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Characterization and identification of Borrelia isolates as Borrelia valaisiana in Taiwan and Kinmen Islands.

Eleven pure cultures of Borrelia from 3 species of wild rodents (Apodemus agrarius, Mus formosanus, Rattus losea) captured in Taichung, located in the center of Taiwan island, and on Kinmen Island were characterized. Five isolates showed restriction fragment length polymorphism (RFLP) patterns of 5S-23S rRNA gene intergenic spacer sequences identical to those of strains 5MT and 10MT, identified as Borrelia valaisiana, which were isolated in the southern tip of South Korea. Although the remaining six isolates showed novel RFLP patterns, these isolates showed more similarity to members of B. valaisiana from Korea, Japan and Europe based on 16S rRNA gene and flagellin gene sequences. This led us to speculate that transmission and proliferation of this type of borrelia occurred between Taiwan and the southern part of South Korea.

Animals↗
PubMed2000

Inhibitory effects of S-methylcysteine and cysteine on the promoting potential of sodium phenobarbital on rat liver carcinogenesis.

The effects of S-methylcysteine (SMC) and cysteine on the promotion stages of rodent hepatocarcinogenesis in a medium-term bioassay previously developed by Ito were examined. Initiation was induced by a single dose of diethylnitrosamine (DEN), followed by dietary administration of the promoter sodium phenobarbital (NaPB) 2 weeks later, for 6 weeks. Partial hepatectomy was conducted on all the animals at week 3. Inhibitory potential was evaluated by analyzing two markers of carcinogenesis, namely numbers of glutathione S-transferase placental form (GST-P)-positive foci, and proliferating cell nuclear antigen (PCNA). In addition, the level of ornithine decarboxylase (ODC), one of the rate-limiting enzymes of polyamine metabolism induced by promoters, was analyzed. SMC and cysteine induced significant reduction in the areas of GST-P-positive foci. A significant reduction in the PCNA index was observed in the entire liver as well as in GST-P-positive areas. SMC also induced down-regulation of the ODC enzyme activity. Thus, SMC and cysteine were found to inhibit the promotion stage of DEN-induced hepatocarcinogenesis. No cocarcinogenic effects were evident on administration of either of these chemicals with NaPB.

Animals↗
PubMed2000

Prevalence of Lyme disease Borrelia spp. in ticks from migratory birds on the Japanese mainland.

Borrelia sp. prevalence in ticks on migratory birds was surveyed in central Japan. In autumn, a total of 1,733 birds representing 40 species were examined for ticks. A total of 361 ticks were obtained from 173 birds of 15 species, and these ticks were immature Haemaphysalis flava (94.4%), Haemaphysalis longicornis, Ixodes columnae, Ixodes persulcatus, Ixodes turdus, and an unidentified Ixodes species. Of these, 27 juveniles of H. flava on Turdus pallidus, Turdus cardis, or Emberiza spodocephala, 2 juveniles of I. persulcatus on T. pallidus, and 1 female H. flava molted from a T. pallidus-derived nymph were positive for the presence of Borrelia by Barbour-Stoenner-Kelly culture passages. In spring, a total of 16 ticks obtained from 102 birds of 21 species were negative for the spirochete. Isolates from 15 ticks were characterized by 5S-23S rRNA intergenic spacer restriction fragment length polymorphism analysis; all isolates were identified as Borrelia garinii with pattern B/B' based on the previous patterning. According to the intergenic spacer sequences, 2 of 15 isolates, strains Fi14f and Fi24f, were highly similar to B. garinii strains 935T of Korea and ChY13p of Inner Mongolia, China, respectively. These findings indicate that Lyme disease-causing B. garinii may have been introduced to Japan by migratory birds from northeastern China via Korea. Additionally, a case of transstadial transmission of B. garinii from nymph to adult H. flava suggests that the infected H. flava may transmit Borrelia to large animals.

Animals↗
PubMed2000

(beta)-catenin mediates the specification of endoderm cells in ascidian embryos.

In the present study, we addressed the role of (beta)-catenin in the specification of embryonic cells of the ascidians Ciona intestinalis and C. savignyi and obtained the following results: (1) During cleavages, (beta)-catenin accumulated in the nuclei of vegetal blastomeres, suggesting that it plays a role in the specification of endoderm. (2) Mis- and/or overexpression of (beta)-catenin induced the development of an endoderm-specific alkaline phosphatase (AP) in presumptive notochord cells and epidermis cells without affecting differentiation of primary lineage muscle cells. (3) Downregulation of (beta)-catenin induced by the overexpression of cadherin resulted in the suppression of endoderm cell differentiation. This suppression was compensated for by the differentiation of extra epidermis cells. (4) Specification of notochord cells did not take place in the absence of endoderm differentiation. Both the overexpression of (beta)-catenin in presumptive notochord cells and the downregulation of (beta)-catenin in presumptive endoderm cells led to the suppression of Brachyury gene expression, resulting in the failure of notochord specification. These results suggest that the accumulation of (beta)-catenin in the nuclei of endoderm progenitor cells is the first step in the process of ascidian endoderm specification.

Alkaline Phosphatase↗
PubMed2000

[Standard chemotherapy for gastrointestinal malignancies based on evidence].

It has been said that there is no standard chemotherapy for gastrointestinal malignancies. However, standard guidelines are essential to increase the level of medical treatment, and the death rate from gastrointestinal malignancies is very high in Japan. FAMTX, standard therapy for gastric cancer abroad, cannot be standard in Japan due to its toxicities. A combination of 5-FU and cisplatin (FP) is most commonly used as the the first choice for chemotherapy, but it's regimens vary. For colon cancer, it is said that a combination of 5-FU and Leucovorin (LV) is standard, but CPT-11, made in Japan, is a promising agent. There is no recommended drug for advanced pancreatic cancer, so palliative care or no chemotherapy are also available alternatives.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

[Nocturnal oxygen desaturation during home oxygen therapy in patients with chronic respiratory disease].

We investigated nocturnal oxygen desaturation (NOD) in 36 patients with stable chronic respiratory disease who were receiving home oxygen, therapy (HOT). Study data included medical history, chest roentgenograms, measurement of daytime arterial blood gases while awake, and spirometry. Each subject underwent full overnight oximetry monitoring. Three patients were excluded from further investigation because of periodic desaturation suggestive of sleep apnea. The remaining 33 subjects were divided into two groups: 21 patients with sequelae of pulmonary tuberculosis (TB-sequela) and 12 patients with chronic obstructive pulmonary disease (COPD). The COPD group was divided into two subgroups according to the Burrows classification (Am Rev Resp Dis. 90: 14-27, 1964): 5 patients with type A (Type A) and 7 patients with type B (Type B) COPD. The percentages of total sleep time with SaO2 < or = 85% (DST 85) and SaO2 < or = 90% (DST 90) were calculated for each subject. NOD was defined as DST 85 > or = 1%. Arterial oxygen partial pressure (PaO2) while awake was > or = 60 Torr in all subjects. No difference was observed in mean awake PaO2 values between the TB-sequela and COPD groups. NOD was detected in 8 TB-sequela patients but in none of the COPD patients. Mean DST 85 and DST 90 values were significantly (p < 0.05) higher for the TB-sequela group than for the COPD group. Of 15 TB-sequela patients who were able to complete spirometry tests, 6 had NOD. All 6 of these patients had hypercapnia while awake (PaCO2 > or = 50 Torr) and reduced vital capacity (< or = 50% predicted). No difference was observed in mean DST 90 or DST 85 values between the TypeA and TypeB COPD subgroups. We conclude that NOD is common in patients with chronic stable respiratory disease treated with HOT despite daytime euoxia. TB-sequela patients with hypercapnia and restrictive ventilatory impairment are at high risk for NOD.

Aged↗
PubMed2000

[Clinical significance of ambulatory intraesophageal bilirubin monitoring in diagnosis of gastroesophageal reflux].

To evaluate the usefulness of ambulatory intraesophageal bilirubin monitoring in the diagnosis of GER, 38 patients with reflux symptoms and 7 controls were studied, using Bilitec 2000. The % time of bilirubin and acid reflux was less than 5% in all of the controls. In 3 patients of NUD, % time of acid reflux was less than 5%, but that of bilirubin was more than 8% in 2 patients. Acid reflux was found only in 1 of 4 patients who had a history of subtotal gastrectomy, but abnormal bilirubin reflux was found in all of 4 patients. In the other 31 patients, a significant difference was found in the % time of bilirubin reflux by the severity of reflux esophagitis, whereas this difference was not found in that of acid reflux. Intraesophageal bilirubin monitoring is useful in the diagnosis of GER and is essential in patients with hypochlorhydria or minimal reflux.

Adult↗
PubMed2000

MRI and arthroscopic findings in the temporomandibular joint after mandibulectomy including the unilateral condyle. Report of two cases.

In this report, the MRI and arthroscopic findings in the temporomandibular joint (TMJ) of two patients who underwent partial mandibulectomy including the condyle are presented. The disc and superior joint compartment of the affected TMJs were preserved in both patients. MRI of the affected TMJs without condyle demonstrated that the intermediate zone of the discs was located anteriorly to the summit of the articular eminence. Joint effusion was detected in the superior joint compartment of one patient. Fibrous adhesions were observed arthroscopically in the superior joint compartment of both affected TMJs. In contrast, no specific findings were demonstrated in the contralateral TMJs connected with the residual mandibular fragment.

Adult↗
PubMed2000

Thoracic esophageal cancer recurred later than 2 years after esophagectomy with extended lymphadenectomy.

PURPOSE: Although the majority of recurrence was found in 2 years after esophagectomy, esophageal cancer could recur lately. To find efficient follow up, the patients were compared by periods of recurrence detected. SUBJECTS AND METHODS: Esophagectomized 227 patients were subjected. Median follow up period was 1289 days. The disease recurred in 84 patients (Group A) in 2 years after surgery and in 17 (Group B) lately. Clinicopathological factors were compared between these 2 groups. RESULTS: There was no difference in background and clinicopathological factors, except Group A was at significantly advanced stage than B. The most common pattern of recurrence was hematogeneous in Group A, whereas lymphatic in Group B, which was significantly different. In Group B, survival rate of patients detected by lymphatic recurrence, which responded to radiation, was higher than that detected by hematogeneous one. CONCLUSION: To prolong survival, the patients should be carefully followed up later than 2 years after surgery with regard for lymphatic recurrence.

Aged↗
PubMed1999

Deletion of the COOH-terminal region of p73alpha enhances both its transactivation function and DNA-binding activity but inhibits induction of apoptosis in mammalian cells.

The candidate tumor suppressor p73 has a high sequence homology with p53 within the NH2-terminal transactivation domain, the sequence-specific DNA-binding region, and the oligomerization domain. However, p73alpha, which is most abundantly expressed in many tissues and cells among the alternatively spliced forms of p73, has an additional long COOH-terminal tail that might distinguish the function of p53 and p73alpha or other p73 splicing variants. To examine the functional role of the p73alpha COOH-terminal region, we generated a series of p73alpha truncation mutants including p73alpha(1-247) (retaining only a transactivation domain), p73alpha(1-427) (lacking the most COOH-terminal region including a SAM domain), and p73alpha(1-548) (deleting an extreme COOH-terminal region except a SAM domain). When transfected into COS cells, all of p73alpha, p73alpha(1-548), and p73alpha(1-427) localized in the cellular nucleus, whereas p73alpha(1-247) localized in both nucleus and cytoplasm. Intriguingly, when compared with p73alpha, both p73alpha(1-427) and p73alpha(1-548) showed a significant stimulation of the transcription of luciferase reporters harboring three p53-responsive promoters (p21(Waf1), Mdm2, and Bax) in p53-deficient SAOS-2 cells. Gel retardation assays showed that DNA-binding activity of p73alpha(1-427) and p73alpha(1-548) was increased as compared with that of the full-length p73alpha. However, the colony formation assays using SAOS-2 cells demonstrated that, contrary to p73alpha, transfection of p73alpha(1-427) or p73alpha(1-548) resulted in no significant reduction of the number of colonies. These suggest that the distal COOH-terminal region of p73alpha is a cis- or trans-acting regulatory domain and regulates its functions diversely.

Alternative Splicing↗