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Biomedical subjects

K Kondo

Publications and source records attributed to K Kondo.

At least 19 recordsLinked to original sources
PubMed2006

Surface acceleration of fast electrons with relativistic self-focusing in preformed plasma.

We report an observation of surface acceleration of fast electrons in intense laser-plasma interactions. When a preformed plasma is presented in front of a solid target with a higher laser intensity, the emission direction of fast electrons is changed to the target surface direction from the laser and specular directions. This feature could be caused by the formation of a strong static magnetic field along the target surface which traps and holds fast electrons on the surface. In our experiment, the increase in the laser intensity due to relativistic self-focusing in plasma plays an important role for the formation. The strength of the magnetic field is calculated from the bent angle of the electrons, resulting in tens of percent of laser magnetic field, which agrees well with a two-dimensional particle-in-cell calculation. The strong surface current explains the high conversion efficiency on the cone-guided fast ignitor experiments.

Journal Article↗
PubMed2006

The balance of VEGF-C and VEGFR-3 mRNA is a predictor of lymph node metastasis in non-small cell lung cancer.

A positive association between vascular endothelial growth factor-C (VEGF-C) expression and lymph node metastasis has been reported in several cancers. However, the relationship of VEGF-C and lymph node metastasis in some cancers, including non-small cell lung cancer (NSCLC), is controversial. We evaluated the VEGF-C and vascular endothelial growth factor receptor-3 (VEGFR-3) expression in NSCLC samples from patients who had undergone surgery between 1998 and 2002 using real-time quantitative RT-PCR and immunohistochemical staining. We failed to find a positive association between VEGF-C and VEGFR-3 mRNA expression and lymph node metastasis in NSCLC. An immunohistological study demonstrated that VEGF-C was expressed not only in cancer cells, but also in macrophages in NSCLC, and that VEGFR-3 was expressed in cancer cells, macrophages, type II pneumocytes and lymph vessels. The VEGF-C/VEGFR-3 ratio of the node-positive group was significantly higher than that of the node-negative group. Immunohistochemical staining showed that VEGFR-3 was mainly expressed in cancer cells. The immunoreactivity of VEGF-C and VEGFR-3 was roughly correlated to the mRNA levels of VEGF-C and VEGFR-3 in real-time PCR. VEGF-C mRNA alone has no positive association with lymph node metastasis in NSCLC. The VEGF-C/VEGFR-3 ratio was positively associated with lymph node metastasis in NSCLC. This suggests that VEGF-C promotes lymph node metastasis while being influenced by the strength of the VEGF-C autocrine loop, and the VEGF-C/VEGFR-3 ratio can be a useful predictor of lymph node metastasis in NSCLC.

Adult↗
PubMed2006

IRES-dependent regulation of FGF-2 mRNA translation in pathophysiological conditions in the mouse.

The mRNA coding for FGF-2 (fibroblast growth factor 2), a major angiogenic factor, is translated by an IRES (internal ribosome entry site)-dependent mechanism. We have studied the role of the IRES in the regulation of FGF-2 expression in vivo, under pathophysiological conditions, by creating transgenic mice lines expressing bioluminescent bicistronic transgenes. Analysis of FGF-2 IRES activity indicates strong tissue specificity in adult brain and testis, suggesting a role of the IRES in the activation of FGF-2 expression in testis maturation and brain function. We have explored translational control of FGF-2 mRNA under diabetic hyperglycaemic conditions, as FGF-2 is implied in diabetes-related vascular complications. FGF-2 IRES is specifically activated in the aorta wall in streptozotocin-induced diabetic mice, in correlation with increased expression of endogenous FGF-2. Thus, under hyperglycaemic conditions, where cap-dependent translation is blocked, IRES activation participates in FGF-2 overexpression, which is one of the keys of diabetes-linked atherosclerosis aggravation. IRES activation under such pathophysiological conditions may involve ITAFs (IRES trans-acting factors), such as p53 or hnRNP AI (heterogeneous nuclear ribonucleoprotein AI), recently identified as inhibitory or activatory ITAFs respectively for FGF-2 IRES.

Animals↗
PubMed2006

[Clinical analysis of operative and hospital deaths in primary lung cancer].

In our department, there were 313 thoracic surgeries for primary lung cancer from January 1994 to December 2003. We clinically reviewed for the operative and hospital death (n=18, 5.8%). The patients were 16 males and 2 females (70.6 +/- 5.6 years old). The surgical procedures were 4 pneumonectomies, 13 lobectomies (3 bronchoplasties) and 1 partial resection. The mean interval until postoperative death was 122.5 +/- 156.1 days. There were 5 direct operative deaths within 30 days (1.6%). There were 4 cancer deaths, 2 hemoptyses, 2 operative bleeding, 2 thromboses, 2 cerebral hemorrhages, 1 pyothorax, 1 pneumonia, 1 respiratory failure, 1 multiple organ failure after chemotherapy and 2 unexplained deaths. The patients with pneumonectomy or aged significantly had high mortality. For postoperative complications such as hemoptysis or bleeding, perioperative management that takes these issues into consideration is needed. Furthermore, we must carefully review the preoperative evaluation and combined treatment, because there were many cancer deaths among cases showing early recurrence and metastasis.

Adenocarcinoma↗
PubMed2005

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering.

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Journal Article↗
PubMed2005

Prevention of diet-induced obesity by dietary isomerized hop extract containing isohumulones, in rodents.

OBJECTIVE: Isomerized hop extract (IHE), which consists mainly of isohumulones and is required in the beer brewing process, was investigated for its effects on diet-induced obesity in two strains of mice. DESIGN: C57BL/6N and KK-A(y) mice were fed a standard or high-fat diet containing IHE and their body and tissue weights were measured at various time points. Oral glucose tolerance tests (OGTT) and insulin tolerance tests (ITT) were carried out in high-fat diet-fed C57BL/6N mice. The effects of IHE on intestinal lipid absorption were examined in Wistar rats using a plasma triacylglycerol assay after oral administration of a lipid emulsion. Fecal lipid levels were also measured in these animals after they were fed a high-fat diet containing IHE for 15 days. The effects of IHE on pancreatic lipase activity and the expression of genes involved in hepatic lipid metabolism were also examined using an in vitro assay and quantitative RT-PCR, respectively. RESULTS: Supplementation of high-fat-containing chow with IHE reduced body weight gain and improved glucose tolerance in our experimental mice. A reduction in body weight gain was also observed in C57BL/6N mice fed a standard diet containing IHE. Wistar rats fed a high-fat diet containing IHE showed reduced plasma triacylglycerol levels and an increase in their fecal lipid excretion. Similarly, their pancreatic lipase activity was inhibited and their elevation in plasma triacylglycerol levels seen after the oral administration of lipid emulsion was significantly suppressed. IHE-fed mice showed an increased expression in their lipid oxidation genes and a decreased expression in genes involved in triacylglycerol biosynthesis. CONCLUSION: The inhibition of intestinal dietary fat absorption may be the mechanism by which IHE induces its weight-lowering effects in high-fat diet-fed mice. The modulatory effect of IHE on lipid metabolism may also, at least partly, be responsible for its beneficial effects on body weight gain. These results suggest that IHE may be helpful in humans in preventing diet-induced obesity and perhaps even metabolic syndrome, the latter of which is known to be associated with obesity.

Animals↗
PubMed2005

In vivo assessment of the cutaneous bioavailability of topically applied maxacalcitol.

Maxacalcitol (22-oxacalcitriol), a vitamin D3 analogue, is widely used for the treatment of psoriasis. The effects of topical dermatologic drugs have been assessed by their pharmacodynamic activities, and concentrations in the skin correlate with these activities. In this study, we assessed the cutaneous bioavailability of topically applied maxacalcitol ointment in vivo by tape stripping. Six drug application sites were randomly assigned on the left volar forearm of six healthy men. Fifty milligrams of maxacalcitol ointment (25 microg/g) was applied to each site. After 0 (15 s), 0.5, 1, 2, 4, or 6 h, the ointment was gently removed, and tape stripping was performed. Maxacalcitol was extracted from the tape strips and quantified by liquid chromatographic tandem mass spectrometry. Average concentrations of maxacalcitol in the stratum corneum (SC) were 2.61, 4.37, 6.23, 9.37, and 9.46 microg/g at 0.5, 1, 2, 4, and 6 h, respectively, after drug application. The steady state was attained approx. 4 h after drug application. The cutaneous bioavailability of topical maxacalcitol ointment can be assessed by the tape-stripping method. This approach will probably be useful in the assessment of the bioequivalence of topical dermatologic products and as a parameter for pharmacokinetic/pharmacodynamic studies.

Adhesives↗
PubMed2005

Off-pump coronary artery bypass in a patient with the antiphospholipid syndrome.

Patients with antiphospholipid syndrome (APS) are prone to excessive postoperative morbidity and mortality after cardiovascular surgery because of its thromboembolic derangements. We present a case of coronary artery bypass grafting (CABG) in a patient with primary APS. He suffered from repetitive coronary occlusion after percutaneous transluminal coronary angioplasty (PTCA). Since his lupus anticoagulant level was found to be 217 s (normal, <50 s), he was diagnosed as the primary APS. He received steroid pulsation therapy with 1000 mg of prednisolone, double-filtration plasmapheresis (DFPP) and 50 mg of cyclophosphamide to attenuate the antibody activity. Four months after the last PTCA, he experienced chest pain and approximately 90% of stenosis in the left anterior descending (LAD) lesion was apparent, although the titer for the lupus anticoagulant was reduced to the normal range. He had drug allergy to ticlopidine hydrochloride and aspirin. Taken together, his disease was found to be resistant to these medical treatments, and surgical treatment was considered. Since cardiopulmonary bypass is known to exaggerate its coagulatory and fibrinolytic complications, off-pump CABG (OPCAB) was feasible in this case. The left internal thoracic artery (ITA) was anastomosed to the LAD using the off-pump technique. The procedure was successful, and the postoperative course for 3 years has been satisfactory without any cardiovascular complaints.

Aged↗
PubMed2004

Plasma devices to guide and collimate a high density of MeV electrons.

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Journal Article↗
PubMed2004

Betulinic acid augments the inhibitory effects of vincristine on growth and lung metastasis of B16F10 melanoma cells in mice.

We examined the antitumour effect of a combination of betulinic acid (BA) and vincristine (VCR) on murine melanoma B16F10 cells in vitro and in vivo. Betulinic acid, a pentacyclic triterpene, showed a synergistic cytotoxic effect on melanoma cells by combinational use of VCR. Betulinic acid and VCR induced cell cycle arrest at different points (BA at G1 phase and VCR at G2/M phase) and caused apoptosis in B16F10 melanoma cells. In the in vivo study, VCR inhibited metastasis of tumour cells to the lung. The addition of BA to VCR augmented suppression of the experimental lung metastasis of melanoma cells in C57BL/6 mice. The number of lung nodules of more than 1 mm in diameter in mice treated with BA and VCR was less than that in mice treated with VCR alone. These results suggest that BA is an effective supplement for enhancing the chemotherapeutic effect on malignant melanoma.

Animals↗
PubMed2004

Sex differences due to dehydroepiandrosterone (DHEA) feeding affecting dehydroepiandrosterone sulfate secretion in golden Syrian hamsters.

The metabolism of orally administered dehydroepiandrosterone (DHEA) by male and female golden Syrian hamsters was examined by quantification of DHEA and dehydroepiandrosterone sulfate (DHEAS) in gallbladder bile, urine and feces using high-performance liquid chromatography (HPLC). Plasma levels of DHEA and DHEAS were also determined by radioimmunoassay (RIA). After 5 days of oral DHEA administration (100 mg/kg body weight twice a day), RIA showed that plasma levels of DHEA and DHEAS were increased approximately 3-6 and 4-5 times, respectively, compared to controls. More than 95 % of circulating DHEA (S) in the peripheral blood was DHEAS. There was no significant sex difference in DHEAS plasma levels between male and female animals in the DHEA-supplemented group. However, 0.2 - 0.3 % of ingested DHEA was conjugated to DHEAS and excreted in urine by females, whereas less than 0.002 % was excreted in urine by males (p < 0.005). DHEAS was excreted in bile by males after DHEA supplementation, and the sex differences in DHEAS levels observed in bile were statistically significant (male, 18.7 +/- 7.5 vs. female, 5.6 +/- 3.1 micromol/l) (p < 0.005). Small amounts of ingested DHEA were excreted in an unchanged state in feces, and no sex difference was observed. These results suggest that there is a considerable sex difference in the conjugation and excretion of orally administered DHEA in the hamster.

Administration, Oral↗
PubMed2004

Antibacterial activity of plants used in cooking for aroma and taste.

Thirty-three plants used in cooking for aroma and taste were examined for antibacterial activity against pathogens causing foodborne infections. Vibrio parahaemolyticus and Staphylococcus aureus were sensitive to many kinds of plant extracts, whereas Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis populations decreased in only six, one, and three plant extracts, respectively. The polyphenol content in the plants was significantly different between the antibacterial plants and nonantibacterial plants, indicating that the polyphenols were related to the antibacterial action of these plants. Antibacterial activity of various concentrations of leaf extracts from Japanese persimmon, white cedar, and grape were investigated. Japanese persimmon and white cedar leaf extracts at low concentrations affected L. monocytogenes and V. parahaemolyticus rapidly. With grape leaf extract at low concentrations, the population of L. monocytogenes decreased similarly to Japanese persimmon and white cedar leaves. This study demonstrates that many plants used in cooking for aroma and taste contain polyphenols and exhibit antibacterial activity against foodborne pathogens.

Anti-Bacterial Agents↗
PubMed2003

Cis-acting elements sufficient for induction of FDH1 expression by formate in the methylotrophic yeast Candida boidinii.

The FDH1 gene of Candida boidinii encodes an NAD+-dependent formate dehydrogenase, which catalyzes the last reaction in the methanol dissimilation pathway. FDH1 expression is strongly induced by methanol, as are the promoters of the genes AOD1 (alcohol oxidase) and DAS1 (dihydroxyacetone synthase). FDH1 expression can be induced by formate when cells are grown on a medium containing glucose as a carbon source, whereas expression of AOD1 and DAS1 is completely repressed in the presence of glucose. Using deletion analyses, we identified two cis-acting regulatory elements, termed UAS-FM and UAS-M, respectively, in the 5' non-coding region of the FDH1 gene. Both elements were necessary for full induction of the FDH1 promoter by methanol, while only the UAS-FM element was required for full induction by formate. Irrespective of whether induction was achieved with methanol or formate, the UAS-FM element enhanced the level of induction of the FDH1 promoter in a manner dependent on the number of copies, but independent of their orientation, and also converted the ACT1 promoter from a constitutive into an inducible element. Our results not only provide a powerful promoter for heterologous gene expression, but also yield insights into the mechanism of regulation of FDH1 expression at the molecular level.

Base Sequence↗
PubMed2003

Equation-of-state measurements of polyimide at pressures up to 5.8 TPa using low-density foam with laser-driven shock waves.

The laser-driven equation-of-state (EOS) experiments for polyimide are presented. The experiments were performed with emission measurements from the rear sides of shocked targets at up to a laser intensity of 10(14) W/cm(2) or higher with 351 nm wavelength and 2.5 ns duration. Polyimide Hugoniot data were obtained up to 0.6 TPa with good accuracy. Applying low-density foam ablator to the EOS unknown material, we also obtained the data at a highest pressure of 5.8 TPa in the nonmetal materials. Those data were in agreement with the theoretical curves.

Journal Article↗