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Biomedical subjects

M Inoue

Publications and source records attributed to M Inoue.

At least 199 records · Page 11Linked to original sources
PubMed2000

Telomerase activity in cancer as a diagnostic and therapeutic target.

Major advances have been made in understanding the role of telomerase in cellular immortalization and carcinogenesis. Human telomeres undergo progressive shortening with cell division, and critical shortening of telomeres with cellular aging triggers a signal for cells to stop dividing and senesce. Telomerase is an enzyme that adds telomeric-repeated sequences to the ends of human chromosome DNA. Telomerase is active in the vast majority of tumors, but not in normal somatic tissues, and prevents progressive shortening of telomeres with cell division, probably giving tumor cells a growth advantage over normal cells. Highly-sensitive PCR-based TRAP (telomeric repeat amplification protocol) assay provided the means to analyze telomerase in a wide variety of tissues. Evidence has been accumulated that this assay may be useful as a potential diagnostic tool for cancer. The constituents of telomerase complex have recently been identified, and human telomerase reverse transcriptase (hTERT) has been found to be responsible for the enzymatic activity of telomerase. Detection of hTERT mRNA may therefore be useful for the screening and diagnosis of cancers. The mechanisms regulating hTERT expression have been extensively analyzed, and transcriptional regulation of hTERT has been found to be essential for hTERT expression, in which several nuclear factors including c-Myc play crucial roles. Understanding of such mechanisms might provide insight into molecular basis of human carcinogenesis and contributes to the development of novel cancer gene therapy targeting telomerase.

Animals↗
PubMed2000

Overdrive suppression of antegrade conduction over the accessory pathway.

In a patient with Wolff-Parkinson-White syndrome whose accessory pathway was primarily capable of bidirectional conduction, antegrade conduction over the accessory pathway was transiently inhibited after rapid atrial or ventricular pacing or after spontaneous termination of atrioventricular reentrant tachycardia. Pacing rate and duration of tachycardia were related to the duration of the suppression of preexcitation, while the coupling interval of the first sinus beat to the last driven or tachycardia beat was irrelevant to the phenomenon. Thus, overdrive suppression of conduction may be the most likely mechanism of this phenomenon.

Adult↗
PubMed2000

Ultrasonic isolation calls in genetically high- and low-emotional rat pups.

The present study was undertaken to investigate the relationship between the emotionality and the modulation of ultrasonic vocalizations in Tsukuba High Emotional (THE) and Tsukuba Low Emotional (TLE) strain rat pups 3-18 days old. The THE pups, while isolated from their dam and littermates and placed in a cold environment, emitted ultrasonic isolation calls at a high rate until day 15. In contrast, ultrasound production was at a consistently low level throughout the test period in the TLE pups. The ultrasonic isolation calls of THE pups were attenuated to the same level as those of the TLE pups after administration of diazepam (1 mg/kg, s.c.), a benzodiazepine receptor agonist, at 6 and 12 days of age. These findings suggest that the high emotionality of the rat pups was reflected largely by the emission of ultrasounds in response to isolation distress rather than the number of the benzodiazepine receptors in the brain that might play a role in physiologic mediation of the rat pup isolation call.

Aging↗
PubMed2000

PSK and OK-432-induced immunomodulation of inducible nitric oxide (NO) synthase gene expression in mouse peritoneal polymorphonuclear leukocytes and NO-mediated cytotoxicity.

We investigated whether PSK (a polysaccharide from the mycelia of Coriolus versicolor) or OK-432 (a streptococcal preparation) can up-regulate inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production in mouse peritoneal polymorphonuclear leukocytes (PMNs). Six hrs after intraperitoneal injection of mice with PSK (2,500 microg/mouse) or OK-432 (100 microg/mouse), mouse peritoneal PMNs were restimulated with PSK (500 microg/ml) or OK-432 (10 microg/ml) plus 100 U/ml of mouse interferon-gamma (IFN-gamma) in vitro. Northern blot analysis showed strong synergism between both PSK and OK-432 and IFN-gamma for the induction of iNOS gene expression. NO production by PMNs was increased up to 20 microM (2 microM/10(6) PMNs/24 hrs) as measured by the Griess reagent method when PMNs were restimulated with PSK or OK-432 plus IFN-gamma for 24 hrs, although tumor cell killing was not detected. NO concentrations of more than 80 microM were required for P815 tumor cell killing. These results suggest that PMNs produce NO after stimulation with PSK or OK-432 in combination with IFN-gamma and may regulate the immune system in vivo, although the NO production induced by these agents is insufficient for tumor cell killing in vitro.

Adjuvants, Immunologic↗
PubMed2000

Decreased turnovers of glutathione and ascorbic acid in watanabe heritable hyperlipidemic rabbits.

Oxidative stress has been postulated to play important roles in the pathogenesis of various diseases such as atherosclerosis in hyperlipidemic subjects. Although the possible role of oxidation of low-density lipoprotein (LDL) in the etiology of atherosclerosis has been studied extensively, the turnover of endogenous antioxidants, which is an important protection system against oxidative stress, remains to be elucidated. The aim of our study was to determine the change of the turnover of endogenous antioxidants such as glutathione and ascorbic acid in case of hyperlipidemia, using Japanese white rabbits (JW) and Watanabe heritable hyperlipidemic rabbits (WHHL). The levels of total glutathione and low molecular weight thiols in the liver, kidney, and other organs in both strains of rabbits were similar. However, a kinetic analysis using L-buthionine-(S,R)-sulfoximine revealed that the rate of glutathione turnover in the liver and kidney of WHHL was about 50%) lower than that of JW. Furthermore, intravenously administered ascorbic acid disappeared more slowly in WHHL than in JW. These results indicate that the turnovers of both glutathione and ascorbic acid in WHHL are depressed in comparison with that in JW. These changes would be closely related to the increased oxidizability of lipids in the circulation of hyperlipidemic subjects.

Animals↗
PubMed2000

Cyclin D1 overexpression in esophageal dysplasia: a possible biomarker for carcinogenesis of esophageal squamous cell carcinoma.

There is controversy as to whether esophageal squamous dysplasia is a pre-cancerous lesion or a non-cancerous lesion. In this study, we conducted an immunohistochemical investigation of cyclin D1, retinoblastoma (Rb), p16INK4 and p27KIP1 expression in 36 squamous dysplasias and 34 early squamous cell carcinomas of the esophagus. The frequency of cyclin D1 overexpression was similar in dysplasias and early cancers (30% vs. 35%). Loss of p16INK4 and p27KIP1 expression was less frequent in dysplasias than in early cancers (p=0.005 and 0.001, respectively). Loss of Rb protein expression was not detected in dysplasia and rarely observed in early cancer (7%). The proliferation cell nuclear antigen index increased from moderate dysplasia to mucosal invasive carcinoma and was correlated significantly with the expression of cyclin D1, p16INK4 and p27KIP1 (p=0.0001, 0.003, and 0.007, respectively). Thus, this study found that cyclin D1 overexpression starts early in dysplasia and could be a useful marker for its malignant potentiality while reduction of p16INK4 and p27KIP1 occurs during the transformation from dysplasia to cancer. These findings suggest that esophageal dysplasia should be treated as a precancerous lesion.

Biomarkers, Tumor↗
PubMed2000

Establishment of a visible peritoneal micrometastatic model from a gastric adenocarcinoma cell line by green fluorescent protein.

To establish a visible peritoneal micrometastatic model, an enhanced green fluorescent protein (EGFP) expressing plasmid vector was transfected into the gastric cancer cell line, MKN-45. Highly expressing EGFP cells were injected into the peritoneal cavity of nude mice. Then, the peritoneum and abdominal organs were harvested and observed on days 1, 4 and 7. Fluorescence stereomicroscopy identified peritoneal micrometastases that had been undetected by stereomicroscopy. Micrometastases as small as a single cell are detectable in this model. This peritoneal micrometastatic model should be a useful tool for research on metastasis of gastric cancer.

Adenocarcinoma↗
PubMed2000

[Antitumor effect of the angiogenesis inhibitor, TNP470, on squamous cell carcinoma cells in head and neck cancer].

The antitumor effect of the angiogenesis inhibitor TNP470, O-(chloro-acetyl-carbamoyl) fumagillol, a synthetic analogue of fumagillin, was studied in vitro and in vivo on, cell line KB which produced interleukin (IL)-8. In vitro, TNP470 reduced the production of IL-8 from KB cells, the same as anti-IL-8 antibody (Ab.) The combination of anti-IL-8 Ab (10 micrograms/ml) and TNP470 (10 ng/ml) significantly inhibited the proliferation of KB cells, compared to no treatment (p < 0.05). Proliferation of KB cells was also significantly more suppressed by simultaneous treatment of cisplatin and TNP470 (1 mg/ml), than cisplatin alone. The in vivo antitumor effect of TNP470 was studied using anti-IL-8 Ab, anti-vascular endothel growth factor (VEGF) Ab, and TNP470, in administered by different routes, i.e., intratumoral (i.t.), intraperitoneal (i.p.), and intravenous. TNP470 (10 mg/ml) showed an antitumor effect, and intratumoral administration of TNP470 was the most effective route. Combined administration of anti-IL-8 Ab (i.p.) and TNP470 (i.t.) reduced tumor volume more than anti-IL-8 Ab alone did. These results suggest that the combination of TNP470, cisplatin, and anti-IL-8 Ab could be a beneficial treatment for solid tumors of the head and neck.

Angiogenesis Inhibitors↗
PubMed2000

Detection of bisphenol-A in dental materials by gas chromatography-mass spectrometry.

The xenoestrogenic substance bisphenol-A is widely used as a synthetic precursor of resin monomers, such as bisphenol-A diglycidyl methacrylate. Reports describing the release of bisphenol-A from polymerized resin into saliva have aroused considerable concern regarding exposure to xenoestrogen by dental treatment. The purpose of the present study was to demonstrate a reliable methodology of detecting the trace amounts of bisphenol-A in dental materials. Bisphenol-A was separable from bisphenol-A diglycidyl methacrylate, which is often employed as the principal dimethacrylate monomer, by selective extraction with a Sep-Pak C18 cartridge. Using this extraction method in combination with a gas-chromatography mass-spectrometry, we have obtained evidence that all unpolymerized materials used in this study were contaminated with bisphenol-A. Quantitative analysis using a deuterium-labeled compound as an internal standard revealed bisphenol-A contents in commercial dental materials ranging from < 1 microgram/g material to about 20 micrograms/g material. The polymerized dental materials released up to 91.4 ng bisphenol-A/g material into phosphate buffered saline during 24-h incubation. These results indicate that bisphenol-A can be released from dental materials, however the leachable amount would be less than 1/1000 of the reported dose (2 micrograms/kg body weight/day) required for xenoestrogenisity in vivo.

Benzhydryl Compounds↗
PubMed2000

[The result of mass screening of 1997 for prostatic cancer in Isesaki City].

PURPOSE: Screening by only prostate specific antigen (PSA) for prostate cancer was started since PSA had been added to mass screening as one of check lists in 1997 in Isesaki city, Gunma pref. We expected PSA screening to be introduced into other areas. We therefore studied how to perform a screening procedure for prostate cancer as well as discussed our result of the screening conducted lately. MATERIALS AND METHODS: 1,382 out of 1,423 Isesaki citizens who took mass screening aged 40 to 64 were chosen. Regardless of age, men with a serum PSA level equal or larger than 4.1 ng/ml (Tandem R) were selected for second screening since we determined it was a cut-off level for further check-up. Of those men, 38 were requested for second screening and actually only 24 took it. All these men took PSA check-up again, furthermore 23 took transrectal examination (TRE) and/or transrectal ultra sonography (TRUS) except for one of them. The next screening was requested for sixteen of them. Prostate biopsy was conducted for all of them. RESULTS: More old men took screening and were diagnosed prostate cancer. The findings derived from such diagnosis showed one of them aged 50 to 59 and six of them aged 60 to 64 had the cancer. Moreover, four out of twenty with PSA level ranging 4.1 to 10.0 ng/ml and all of three with PSA level over 20.0 ng/ml had the cancer. Five out of sixteen with a positive sign for further PSA check-ups had the cancer. All the three suspect of the cancer by TURS and DRE had prostate cancer. Two of seven with PSA negative showed suspicion of prostate cancer and had the cancer. No neo-adjuvant and total prostatectomy was conducted for four with 4.0 to 10.0ng/ml diagnosed T2N0 M0. One of them with PSA equal or over 20.0 ng/ml was diagnosed T3N0M0. After hormone therapy its PSA decreased to that equal or under 0.5 ng/ml. Total prostatectomy was conducted for it. CONCLUSION: It is not proved that only PSA mass screening for prostatic cancer contributes to detect early cancer and better prognosis cure case. For the proof, it will be nessary that PSA mass screening is examined more people in the wide area. We conclude men aged 65 to 69 also should take PSA check-up based on epidemiological feature of prostatic cancer.

Adult↗
PubMed2000

In vivo signal transduction of nociceptive response by kyotorphin (tyrosine-arginine) through Galpha(i)- and inositol trisphosphate-mediated Ca(2+) influx.

Kyotorphin is a dipeptidic neuropeptide (tyrosine-arginine) that has specific receptor coupled to G(i) and phospholipase C and elicits Met-enkephalin release. Here, we attempted to demonstrate the in vivo evidence for the presynaptic mechanism by analyzing its nociceptive responses after peripheral application. Kyotorphin elicited potent nociceptive flexor responses at extremely low doses between 0.1 and 100 fmol after the intraplantar injection into the hind-limb of mice. The site of action of kyotorphin-induced responses was identified to be on nociceptor endings, because the responses were markedly attenuated by intrathecal pretreatments with Galpha(i1) or Galpha(i2) antisense-oligodeoxynucleotides. Similar mechanisms were observed with histamine-induced nociceptive responses, except for the use of different antagonist and Galpha(q/11) antisense-oligodeoxynucleotide. Both responses were characterized to be mediated through inositol trisphosphate receptor-gated Ca(2+) influx, because they were blocked by xestospongin C, an allosteric antagonist for inositol trisphosphate receptor and EGTA, but not thapsigargin. Because the nociceptive responses by compound 48/80 through histamine-release from mast cells were completely abolished by thapsigargin, it is unlikely that the dose of thapsigargin is not sufficient to block both responses. All of these in vivo findings strongly support our previous view that kyotorphin elicits Ca(2+) influx through inositol trisphosphate receptor located at presynaptic plasma membranes.

Analgesics↗
PubMed2000

Protein kinase C-mediated acute tolerance to peripheral mu-opioid analgesia in the bradykinin-nociception test in mice.

We studied the acute tolerance liability of peripheral opioid analgesia in mice. The analgesia was assessed by the inhibition of bradykinin (BK)-induced nociceptive action by using a newly developed flexor reflex paradigm. Morphine [intraplantarly (i.pl.)] given ipsilaterally to BK showed a dose-dependent reduction of the BK (2 pmol) responses, whereas the administration of 10 nmol of morphine into the contralateral side failed to show any significant analgesic effects. Furthermore, DAMGO ([D-Ala(2),MePhe(4), Gly-ol(5)]-enkephalin), a mu-opioid receptor (MOR) agonist, and U-69593, a kappa-opioid receptor (KOR) agonist, but not DSLET ([D-Ser(2)]Leu-enkephalin-Thr(6)), a delta-opioid receptor agonist, showed similar analgesia on the BK responses. The morphine- or U-69593 [(5alpha,7alpha, 8beta)-(+)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4,5]dec -8yl] benzeneacetamide]-induced analgesia was markedly attenuated by the intrathecal injection of each antisense oligodeoxynucleotide for the MOR or KOR, respectively, suggesting that these peripheral analgesia are mediated through MORs and KORs located on nociceptor endings, respectively. As BK response was completely recovered to the control level 4 h after morphine (3 nmol i.pl.) or U-69593 (10 nmol i.pl.) administration, these compounds were challenged again to see the inhibition of BK responses. Although morphine analgesia by the second challenge was markedly attenuated, U-69593 analgesia was not. The attenuated morphine analgesia was completely reversed by the pretreatment of calphostin C, Go6976, or HBDDE, a protein kinase C inhibitor, but not by KT-5720, a protein kinase A inhibitor. These results suggest that selective acute tolerance of peripheral morphine analgesia, but not U-69593 analgesia, through MORs and KORs located on polymodal nociceptors, respectively, in the bradykinin-nociception test in mice was mediated through protein kinase C activation.

Analgesics, Opioid↗
PubMed2000

Up-regulation of cyclooxygenase-2 in squamous carcinogenesis of the esophagus.

Cyclooxygenase-2 (COX-2) is overexpressed in various types of human malignancies including squamous cell carcinomas (SCCs) of the esophagus, but little is known about COX-2 expression in premalignant esophageal squamous dysplasia. To elucidate the role of COX-2 in esophageal carcinogenesis, we examined the expression of this enzyme in normal squamous epithelium (n = 42), squamous dysplasia [high-grade dysplasia (HGD, n = 41; low-grade dysplasia (LGD, n = 33)]; carcinoma in situ (n = 16), mucosal invasive carcinoma (n = 18), and advanced SCC (n = 45). Immunohistochemistry showed a significantly high COX-2 expression in HGD compared with other lesions. The COX-2 score, an index determined by intensity and positivity of COX-2 staining (maximum 3.0), was 0.29 +/- 0.04 in normal esophagus, 1.75 +/- 0.11 in LGD, 2.89 +/- 0.05 in HGD, 2.17 +/-0.18 in CIS, 1.95 +/- 0.22 in mucosal invasive carcinoma, and 1.81 +/- 0.08 in advanced SCC. Results of reverse transcription-PCR assays confirmed those obtained by immunohistochemistry. COX-2 expression correlated with proliferation activity assessed by the proliferating cell nuclear antigen index in dysplastic lesions (P = 0.001) but not in SCCs. COX-2 expression in SCC did not correlate with various clinicopathological parameters including prognosis. Our results indicate that COX-2 is a sensitive marker for HGD and suggest that COX-2 may be involved in early stages of squamous carcinogenesis of the esophagus.

Antibodies, Monoclonal↗
PubMed2000

Adenoviral expression of p53 represses telomerase activity through down-regulation of human telomerase reverse transcriptase transcription.

Telomerase activation is a critical step in cellular immortality and oncogenesis. The activity of telomerase is known to be correlated with cell proliferation, but its regulation by cell cycle regulators is not well understood. In the present study, we examined the effects of p53 on telomerase activity. Wild-type p53 was introduced into SiHa cells via a recombinant adenoviral vector, Ad5CMV-p53, and change in telomerase activity was examined by quantitative telomerase assay. Telomerase activity in the Ad5CMV-p53-infected cells was significantly repressed 36 h after infection following down-regulation of human telomerase catalytic subunit [human telomerase reverse transcriptase (hTERT)] mRNA expression, whereas no change in telomerase activity was observed in the cells infected with control vector AdSCMV-beta-gal. Interestingly, repression of telomerase activity was an early event that preceded cell growth inhibition or apoptosis induced by p53 overexpression, suggesting that p53 directly regulates telomerase activity. Transient expression assays using hTERT-promoter reporter constructs revealed that overexpression of p53 significantly repressed promoter activity of hTERT. 5'-Truncation of the promoter sequences revealed that the proximal core promoter region containing multiple binding sites for transcription factor Spl was responsible for p53-mediated transcriptional repression. Mutations in these binding sites for Spl led to failure of p53 to repress transcription. These findings suggest that p53 repressed telomerase activity through down-regulation of hTERT transcription and that interaction of p53 with Sp1 or other transcription factors may be involved in this regulation.

Adenoviridae↗
PubMed2000

[Drug-resistant bacteria of current topics and their resistance mechanisms--ESBL].

Under the influence of antimicrobial agents, bacteria that primarily produce TEM-Type or SHV-Type beta-lactamases developed point mutations in structural genes which served to extend the substrate specificity of the enzymes. Undoubtedly, CTX-resistance rates increased in E. coli and K. pneumoniae in the recent years. It is strongly suggested that a survey of ESBL-producing clinical isolates of E. coli and K. pneumoniae should also be required for rigorous detection methods.

Escherichia coli↗