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Toru Kobayashi

Publications and source records attributed to Toru Kobayashi.

27 records · Page 2Linked to original sources
PubMed2003

Development of a PCR assay for detection of Enterobacteriaceae in foods.

A broad-range PCR assay for the detection of bacteria belonging to the Enterobacteriaceae family was developed in this study. Primers targeting the bacterial 16S rRNA gene were newly designed and used in this PCR assay. To determine the specificity of the assay, 72 different bacterial species (of 49 genera), 2 fungi, 3 animals, and 4 plants were tested. Results were positive for every tested Vibrioaceae or Enterobacteriaceae strain except Proteus mirabilis. For all other bacterial strains and eukaryotes tested, results were negative. Bacterial DNA for PCR was prepared by a simple procedure with the use of Chelex 100 resin from culture after growth in brain heart infusion medium. To test this PCR assay for the monitoring of the Enterobacteriaceae family, either Escherichia coli or Salmonella Enteritidis was inoculated into various foods as an indicator. Prior to the PCR, the inoculation of 10 to 40 CFU of bacteria per g of food was followed by a 5-h enrichment culture step, and the PCR assay allowed the detection of bacterial cells. When actual examinations of the contamination of 15 noodle foods with Enterobacteriaceae by this PCR assay were conducted, 33% (5 of 15) of the samples tested positive. These results agreed with those of the Petrifilm Enterobacteriaceae Count Plate assay. Including the enrichment culture step, the entire PCR detection process can be completed within 7 h.

Colony Count, Microbial↗
PubMed2002

Production of germline chimera in loach (Misgurnus anguillicaudatus) and proposal of new method for preservation of endangered fish species.

As part of the technique for preservation of endangered fish species, germline chimeras using the loach (Misgurnus anguillicaudatus) model were generated by embryonic cell manipulation. Transplanting cells from early-stage embryos of a wild-type strain to the blastoderm of an orange-type strain generated chimeras. Within three days, many of the resulting individuals exhibited a dark pigment on several parts of their body, characteristic of the donor but not of the orange strain. At one year of age, four chimeras (one female and three males) were pair-mated with the orange type, and F(1) was obtained. One of the four F(0) chimeras produced progeny similar to the wild type at a frequency of 0.24% (2/841). The results suggest that this method is a promising technique for the preservation of endangered fish species.

Animals↗
PubMed2002

Mechanisms of acute lumen gain following cutting balloon angioplasty in calcified and noncalcified lesions: an intravascular ultrasound study.

Several studies have shown that mechanisms for lumen enlargement following conventional balloon angioplasty (BA) consist of plaque reduction and vessel expansion. To assess the mechanisms of lumen enlargement after Cutting Balloon (CB) angioplasty, intravascular ultrasound images were analyzed in 180 lesions (89 CB and 91 BA). External elastic membrane (EEM) cross-sectional area (CSA), lumen CSA, and plaque plus media (P+M) CSA were measured before and after angioplasty. In the CB group, lower balloon pressure was utilized (P < 0.0001). DeltaP+M CSA was significantly larger (P = 0.02) and deltalumen CSA showed a trend toward being larger (P = 0.07) compared to BA group. For noncalcified lesions, CB resulted in a larger deltaP+M CSA (P < 0.05) and a smaller deltaEEM CSA (P = 0.10) than BA. For calcified lesions, deltalumen CSA was significantly larger in the CB group (P < 0.05) without significant differences in deltaEEM CSA and deltaP+M CSA. Dissections complicated with calcified lesions were associated with larger deltalumen CSA for the CB group. In conclusion, for noncalcified lesions, CB achieves similar luminal dimensions with larger plaque reduction and less vessel expansion compared to BA. On the other hand, for calcified lesions, the CB achieves larger lumen gain, especially in lesions with evidence of dissections.

Aged↗
PubMed2002

Molecular mechanisms of analgesia induced by opioids and ethanol: is the GIRK channel one of the keys?

Opioids and ethanol have been used since ancient times for pain relief. Opioid signaling is mediated by various effectors, including G protein-activated inwardly rectifying potassium (GIRK) channels, adenylyl cyclases, voltage-dependent calcium channels, phospholipase Cbeta(PLCbeta), and mitogen-activated protein kinases, although it has been unclear which effector mediates the analgesic effects of opioids. Ethanol induces a variety of physiological phenomena via various proteins, including GIRK channels rather than via membrane lipids. GIRK channel activation by either G proteins or ethanol is impaired in weaver mutant mice. The mutant mice may therefore serve as a useful animal model for studying the role of GIRK channels in vivo. Reduced analgesia by using either opioids or ethanol in weaver mutant mice suggests that GIRK channels are important effectors in both opioid- and ethanol-induced analgesia. This hypothesis is supported by similar findings in GIRK2 knockout mice. Among the various effectors coupled with opioid receptors and various targets of ethanol, GIRK channels are the only molecules whose involvement in opioid- and ethanol-induced analgesia has been demonstrated in vivo. The GIRK channel is potentially one of the key molecules in furthering the understanding of the pain control system and in developing advanced analgesics with fewer adverse effects.

Analgesics, Opioid↗
PubMed2002

Functional characterization of an endogenous Xenopus oocyte adenosine receptor.

To investigate the effects of adenosine on endogenous Xenopus oocyte receptors, we analysed defolliculated oocytes injected with mRNAs for the G protein-activated inwardly rectifying K(+) (GIRK) channels. In oocytes injected with mRNAs for either GIRK1/GIRK2 or GIRK1/GIRK4 subunits, application of adenosine or ATP reversibly induced inward K(+) currents, although ATP was less potent than adenosine. The responses were attenuated by caffeine, a non-selective adenosine receptor antagonist. Furthermore, in uninjected oocytes from the same donor, adenosine produced no significant current. The endogenous receptor was activated by two selective A(1) adenosine receptor agonists, N(6)-cyclopentyladenosine (CPA) and N(6)-cyclohexyladenosine (CHA), and antagonized by a selective A(1) adenosine receptor antagonist, 1,3-dipropyl-8-cyclopenylxanthine (DPCPX) at moderate nanomolar concentrations, but insensitive to micromolar concentrations of selective A(2A) and A(3) adenosine receptor agonists, 2-[p-(2-carbonyl-ethyl)-phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS21680) and N(6)-(3-iodobenzyl)-5'-(N-methylcarbamoyl)adenosine (IB-MECA), respectively. However, the pharmacological characteristics of the receptor were different from those of the cloned Xenopus A(1) adenosine receptor and previously proposed adenosine receptors. The adenosine-induced GIRK currents were abolished by injection of pertussis toxin and CPA inhibited forskolin-stimulated cyclic AMP accumulation. We conclude that an adenosine receptor on the Xenopus oocyte membrane can activate GIRK channels and inhibit adenylyl cyclase via G(i/o) proteins. Moreover, our results suggest the existence of an endogenous adenosine receptor with the unique pharmacological characteristics. As the receptor was activated by nanomolar concentrations of adenosine, which is a normal constituent of extracellular fluid, the receptor may be involved in some effects through the G(i/o) protein signalling pathways in ovarian physiology.

Adenosine↗
PubMed2002

Impact of the p53 status of the tumor cells on the effect of reactor neutron beam irradiation, with emphasis on the response of intratumor quiescent cells.

Human head and neck squamous cell carcinoma cells transfected with mutant p53 (SAS/mp53) or with neo vector as a control (SAS/neo) were inoculated subcutaneously into both the hind legs of Balb/cA nude mice. Tumor-bearing mice received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all proliferating (P) cells in the tumors. After administration of sodium borocaptate-10B (BSH) or p-boronophenylalanine-10B (BPA), the tumors were irradiated with neutron beams. The tumors not treated with 10B-compound were irradiated with neutron beams or gamma-rays. The tumors were then excised, minced and trypsinized. The tumor cell suspensions thus obtained were incubated with a cytokinesis blocker, and the micronucleus (MN) frequency in cells without BrdU labeling (=quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. Meanwhile, 6 h after irradiation, tumor cell suspensions obtained in the same manner were used for determining the frequency of apoptosis in Q cells. The MN and apoptosis frequencies in total (P+Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Without 10B-carriers, in both tumors, the relative biological effectiveness of neutrons was greater in Q cells than in total cells, and larger for low than high cadmium ratio neutrons. With 10B-carriers, the sensitivity was increased for each cell population, especially for total cells. BPA increased both frequencies for total cells more than BSH. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that of BSH-treated Q cells. These sensitization patterns in combination with 10B-carriers were clearer in SAS/neo than in SAS/mp53 tumors. The p53 status of the tumor cells had the potential to affect the response to reactor neutron beam irradiation following 10B-carrier administration.

Animals↗
PubMedDate not supplied

Clinical review of the Japanese experience with boron neutron capture therapy and a proposed strategy using epithermal neutron beams.

Our concept of boron neutron capture therapy (BNCT) is selective destruction of tumor cells using the heavy-charged particles yielded through 10B(n, alpha)7 Li reactions. To design a new protocol that employs epithermal neutron beams in the treatment of glioma patients, we examined the relationship between the radiation dose, histological tumor grade, and clinical outcome. Since 1968, 183 patients with different kinds of brain tumors were treated by BNCT; for this retrospective study, we selected 105 patients with glial tumors who were treated in Japan between 1978 and 1997. In the analysis of side effects due to radiation, we included all the 159 patients treated between 1977 and 2001. With respect to the radiation dose (i.e. physical dose of boron n-alpha reaction), the new protocol prescribes a minimum tumor volume dose of 15 Gy or, alternatively, a minimum target volume dose of 18 Gy. The maximum vascular dose should not exceed 15 Gy (physical dose of boron n-alpha reaction) and the total amount of gamma rays should remain below 10 Gy, including core gamma rays from the reactor and capture gamma in brain tissue. The outcomes for 10 patients who were treated by the new protocol using a new mode composed of thermal and epithermal neutrons are reported.

Adolescent↗
PubMedDate not supplied

Surgery for hepatocellular carcinoma with tumor thrombus extending into the right atrium: report of a successful resection without the use of cardiopulmonary bypass.

Hepatocellular carcinomas, of which the tumor thrombus extends into the right atrium via the inferior vena cava, may soon cause fatal complications. Only surgery can be an effective treatment. This procedure usually needs the aid of cardiopulmonary bypass. We recently experienced a successful surgery to remove thrombus combined with hepatectomy. Reporting the detailed technique, both associated diagnosis and intraoperative management are discussed herein. We were able to perform hepatectomy of tumor thrombus in the right atrium without the use of cardiopulmonary bypass or veno-venous bypass. The tumor thrombus was removed from the right atrium into the suprahepatic inferior vena cava by reducing the liver on the tail side. And after total hepatic vascular exclusion was achieved, the intracaval tumor thrombus and the right lobe of the liver were removed en bloc. The operation took 545 minutes and the total hepatic vascular exclusion period was 32 minutes. The postoperative course was uneventful. There are some key points for this procedure. Preoperative or intraoperative US is essential in judging whether tumor thrombus can be removed from the right atrium into the inferior vena cava by reducing the liver or not. Test clamping of the inferior vena cava prior to total hepatic vascular exclusion will enable us to judge whether veno-venous bypass during total hepatic vascular exclusion is needed or not. Surgery without the use of cardiopulmonary bypass is safe and can be minimally invasive when it is performed with a reliable diagnosis and technique.

Carcinoma, Hepatocellular↗