Biomedical subjects

K Nagai

Publications and source records attributed to K Nagai.

At least 19 recordsLinked to original sources

PubMed2006

Optimum hot electron production with low-density foams for laser fusion by fast ignition.

We propose a foam cone-in-shell target design aiming at optimum hot electron production for the fast ignition. A thin low-density foam is proposed to cover the inner tip of a gold cone inserted in a fuel shell. An intense laser is then focused on the foam to generate hot electrons for the fast ignition. Element experiments demonstrate increased laser energy coupling efficiency into hot electrons without increasing the electron temperature and beam divergence with foam coated targets in comparison with solid targets. This may enhance the laser energy deposition in the compressed fuel plasma.

Journal Article↗

PubMed2006

Hugoniot data of plastic foams obtained from laser-driven shocks.

In this paper we present Hugoniot data for plastic foams obtained with laser-driven shocks. Relative equation-of-state data for foams were obtained using Al as a reference material. The diagnostics consisted in the detection of shock breakout from double layer Al/foam targets. The foams [poly(4-methyl-1-pentene) with density 130 > rho > 60 mg/cm3] were produced at the Institute of Laser Engineering of Osaka University. The experiment was performed using the Prague PALS iodine laser working at 0.44 microm wavelength and irradiances up to a few 10(14) W/cm2. Pressures as high as 3.6 Mbar (previously unreached for such low-density materials) where generated in the foams. Samples with four different values of initial density were used, in order to explore a wider region of the phase diagram. Shock acceleration when the shock crosses the Al/foam interface was also measured.

Journal Article↗

PubMed2006

Long term smoking with age builds up excessive oxidative stress in bronchoalveolar lavage fluid.

BACKGROUND: Epithelial lining fluid plays a critical role in protecting the lung from oxidative stress, in which the oxidised status may change by ageing, smoking history, and pulmonary emphysema. METHODS: Bronchoalveolar lavage (BAL) was performed on 109 young and older subjects with various smoking histories. The protein carbonyls, total and oxidised glutathione were examined in BAL fluid. RESULTS: By Western blot analysis, the major carbonylated protein in the BAL fluid was sized at 68 kDa, corresponding to albumin. The amount of carbonylated albumin per mg total albumin in BAL fluid was four times higher in older current smokers and three times higher in older former smokers than in age matched non-smokers (p<0.0001, p=0.0003, respectively), but not in young smokers. Total glutathione in BAL fluid was significantly increased both in young (p=0.006) and older current smokers (p=0.0003) compared with age matched non-smokers. In contrast, the ratio of oxidised to total glutathione was significantly raised (72%) only in older current smokers compared with the other groups. There was no significant difference in these parameters between older smokers with and without mild emphysema. CONCLUSIONS: Oxidised glutathione associated with excessive protein carbonylation accumulates in the lung of older smokers with long term smoking histories even in the absence of lung diseases, but they are not significantly enhanced in smokers with mild emphysema.

Adult↗

PubMed2006

Immunohistochemical prognostic factors in resected colorectal lung metastases using tissue microarray analysis.

AIMS: Immunohistochemical prognostic factors of pulmonary metastatic colorectal cancer lesions have not been well investigated. The study was conducted to identify the immunohistochemical prognostic factors of metastasized colorectal cancer. METHODS: We immunohistochemically investigated the expression of insulin-like growth factor-1 receptor (IGF1-R), E-cadherin, beta-catenin, and p53 using a tissue microarray in the surgical specimens of 86 metastatic lesions. RESULTS: The univariate analysis revealed E-cadherin and membrane beta-catenin positive to be prognostic factors. IGF1-R and p53 were not significantly associated with the patient's survival. In multivariate analysis, the reduced expression of E-cadherin, aerogenous spread with floating cancer cell clusters and vascular invasion were independent prognostic factors. CONCLUSIONS: The reduced expression of E-cadherin in the pulmonary metastatic lesions was an independent predictor of poor survival after pulmonary metastasectomy.

Biomarkers, Tumor↗

PubMed2006

Comparison of the immunophenotypes of signet-ring cell carcinoma, solid adenocarcinoma with mucin production, and mucinous bronchioloalveolar carcinoma of the lung characterized by the presence of cytoplasmic mucin.

The latest World Health Organization (WHO) classification divides adenocarcinoma mainly into adenocarcinoma mixed subtypes, acinar adenocarcinoma, papillary adenocarcinoma, bronchioloalveolar carcinoma, and solid adenocarcinoma with mucin production, and it mentions several variants, including fetal adenocarcinoma, mucinous ("colloid") adenocarcinoma, mucinous cystadenocarcinoma, signet-ring adenocarcinoma, and clear cell adenocarcinoma. In general, the mucin-producing adenocarcinoma of the lung comprises signet-ring cell carcinoma (SRCC), solid adenocarcinoma with mucin production (SA), and mucinous bronchioloalveolar carcinoma (m-BAC), mucinous ("colloid") adenocarcinomas and/or mucinous cystadenocarcinoma, and mucoepidermoid carcinoma. As SRCC, SA, and m-BAC exhibit distinct clinical features, it is important to identify differences in their immunohistochemical characteristics to better understand their histogenesis. In this study we analysed SRCC, SA, m-BAC, normal lung, and foregut-related secretory tissue for immunohistochemical differences using tissue microarrays. SRCC and SA showed high expression of MUC1 (97.4% and 100%, respectively), cytokeratin (CK) 7 (both 100%), and thyroid transcription factor-1 (TTF-1) (81.1% and 100%, respectively). They also showed low expression of MUC5AC (25.5% and 21.1%, respectively) and MUC6 (18.3% and 10.5%, respectively), whereas m-BAC showed high expression of MUC5AC (97.5%), MUC6 (75.0%), and CK7 (94.7%), but low expression of MUC1 (57.5%), and TTF-1 (27.5%). Hierarchical clustering showed that the immunophenotypes of SRCC and SA belong to the same category as alveolar lining cells, whereas m-BAC clustered onto another branch with gastric foveolar cells and bronchial goblet cells. These immunohistochemical findings support the results of our previous clinicopathological analysis of SRCC of the lung showing that SRCC occurs anatomically in the peripheral portion of the lung rather than in the bronchial gland-bearing portion.

Adenocarcinoma↗

PubMed2006

Identification of nuclear spliceosomal antigens targeted by NOD mouse antibodies following sodium iodide intake.

The non-obese diabetic (NOD) mouse spontaneously develops a range of autoreactive responses including an autoantibody response to nuclear antigens. As elevated dietary iodine has been shown to increase thyroid autoimmune pathology in NOD mice, the effect of sodium iodide (NaI) on the development of anti-nuclear antibodies (ANA) was assessed. Interestingly, the NaI symporter is expressed in both thyroid and salivary glands. Elevated dietary iodine was found to increase the percentage of male NOD mice developing autoantibodies. Specifically, the nuclear autoantibodies that develop in NOD mice were shown to target specific spliceosomal components. The target specificity of the autoantibodies was determined using recombinant spliceosomal proteins and shown to include U1A, U170K, U2B'', U2A', as well as the Sm proteins D1, D2, and B. The autoantibody isotypes most consistently represented were IgG2a and IgG2b.

Amino Acid Sequence↗

PubMed2006

Exploration of genes showing intramuscular fat deposition-associated expression changes in musculus longissimus muscle.

Marbling, as defined by the amount of intramuscular fat, is an economically important trait in beef cattle. Intramuscular fat deposition is postulated to arise mainly from a series of adipogenic events in intramuscular adipocyte-lineage cells and in the physiological or anatomical milieux surrounding them. This study was designed to investigate gene-expression patterns associated with fat deposition in musculus longissimus muscle, including adipocyte-lineage cells and part of the milieux. Differential-display PCR (ddPCR) was used to examine expression differences between low-marbled and high-marbled steer groups at 8, 10, 12 and 14 months of age, encompassing the time that marbling starts to appear. Seventy-four of 2114 total bands on ddPCR gel-bands were significant (P < 0.05) for the group effect, the interaction effect between group and age, or both the group and the interaction effects. Sequence analysis of 72 of these bands revealed 77 genes, including 35 annotated genes and 42 novel sequences. Among the 35 annotated genes, 6 (BTG2, PDHB, SORBS1, TRDN, TTN and MGP) have been related to changes in intramuscular fat deposition, possibly by exerting effects on adipocyte-lineage cells or on the milieux surrounding them.

Adipose Tissue↗

PubMed2005

Observation of surface Andreev bound States of superfluid 3He by transverse acoustic impedance measurements.

Complex transverse acoustic impedance of the superfluid (3)He-B was measured at the frequencies of 10 to 80 MHz at 17.0 bar by a cw bridge method. The observed temperature dependence was well explained by the quasiclassical theory with random S-matrix model for a diffusive surface. The temperature dependence was influenced by pair breaking and by quasiparticle density of states at the surface, which was drastically modified from the bulk one by the presence of surface Andreev bound states.

Journal Article↗

PubMed2005

A case of double cancer involving oral malignant melanoma and gastrointestinal stromal tumor (GIST).

We report a very rare case of double cancer involving palatal malignant melanoma and gastrointestinal stromal tumor (GIST), a rare tumor of the gastrointestinal tract originating from a primitive mesenchymal cell. After chemotherapy, radiation therapy, and treatment with interferon and OK-432, the GIST was resected and the melanoma disappeared. The patient has had no evidence of recurrent tumor, and the patient's clinical course has been uneventful for 1 year. This is probably the first report of synchronous double cancer involving oral malignant melanoma and GIST.

Aged↗

PubMed2005

Decrease of vascular endothelial growth factor in macrophages from long-term smokers.

Vascular endothelial growth factor (VEGF), a survival factor for endothelial cells and a promoter of angiogenesis, is reportedly expressed in alveolar macrophages (AMs). To investigate whether long-term smoking with age affects VEGF expression in AMs, bronchoalveolar lavage (BAL) was performed on 18 young and 23 older volunteers with various smoking histories. The expressions of VEGF and its functional receptor, fms-like tyrosine kinase (Flt)-1, were quantified in AMs by real-time RT-PCR and, further, the level of VEGF in BAL fluid was determined by ELISA. VEGF mRNA in AMs demonstrated a 1.8-fold reduction in current smokers compared with nonsmokers in older subjects and, furthermore, a 1.5-fold downregulation in those with emphysema, although there was no difference between current smokers and nonsmokers among the young subjects. The downregulation in total VEGF mRNA was supported by the substantial reduction of VEGF121 and VEGF165 isoforms. However, in contrast, Flt-1 mRNA did not differ within the older groups, whereas it was upregulated in young current smokers compared with age-matched nonsmokers. VEGF in BAL fluid is significantly decreased in current smokers compared with nonsmokers, regardless of their age. In conclusion, these data imply that the biological availability of vascular endothelial growth factor in alveolar macrophages is impaired in older current smokers with long-term smoking histories.

Adult↗

PubMed2004

Effect of prostaglandin E1 on inflammatory responses and gas exchange in patients undergoing surgery for oesophageal cancer.

BACKGROUND: Oesophageal surgery causes morbidity and mortality from respiratory complications. We tested the possibility that prostaglandin E1 (PGE1) could reduce inflammatory cytokine responses and improve gas exchange after oesophagectomy. METHODS: We randomized 14 patients into two groups. One group received PGE1 20 ng kg(-1) min(-1) i.v. during anaesthesia (PGE1 group) and the other group did not (control group). Anaesthesia was maintained with sevoflurane and epidural anaesthesia. During oesophagectomy, ventilation of one lung was carried out with a double-lumen bronchial tube. The patients were extubated on or after the first postoperative day. Blood samples were taken at induction of anaesthesia, at the end of thoracotomy, at the end of the operation, 2 h after surgery and on the first day after surgery. RESULTS: The groups were similar for ASA physical status, age, FEV1%, operation time, duration of thoracotomy, intraoperative fluid volume and blood loss. The arterial blood gas and arterial pressure during surgery were also similar in the PGE1 and control groups. However, the PaO2/FiO2 ratio on the first day after surgery was significantly greater in the PGE1 group compared with the control group. Serum concentrations of IL-6 and IL-8 increased after surgery in both groups. IL-6 was significantly less in the PGE1 group at the end of the operation and 2 h after the operation. CONCLUSIONS: Intraoperative PGE1 reduced IL-6 production in patients undergoing oesophagectomy and oxygenation was better in the postoperative period.

Aged↗

PubMed2004

Ion generation in a low-density plastic foam by interaction with intense femtosecond laser pulses.

Energetic proton generation in low-density plastic (C5H10) foam by intense femtosecond laser pulse irradiation has been studied experimentally and numerically. Plastic foam was successfully produced by a sol-gel method, achieving an average density of 10 mg/cm(3). The foam target was irradiated by 100 fs pulses of a laser intensity 1 x 10(18) W/cm(2). A plateau structure extending up to 200 keV was observed in the energy distribution of protons generated from the foam target, with the plateau shape well explained by Coulomb explosion of lamella in the foam. The laser-foam interaction and ion generation were studied qualitatively by two-dimensional particle-in-cell simulations, which indicated that energetic protons are mainly generated by the Coulomb explosion. From the results, the efficiency of energetic ion generation in a low-density foam target by Coulomb explosion is expected to be higher than in a gas-cluster target.

Journal Article↗

PubMed2004

Establishment of a clonal human mesenchymal cell line that retains multilineage differentiation capacity from a spinal hamartoma.

We isolated a single-cell-derived cell line from a spinal hamartoma, a which occurred in a newborn boy and was associated with a rudimentary limb. The maternal cells (HHC-7) differentiated into osteoblasts, chondrocytes, adipocytes, and skeletal muscles when they were cultured in differentiation-inducing media specific to each mesenchymal cell. We isolated a single-cell-derived clonal cell line (Clone K) after transfection with SV40 T antigen. These cells expressed CD73 and CD117, while being negative for expression of CD45. Clone K cells cultured in an osteogenic differentiation medium increased ALP activity and expressed mRNAs for Runx2 and osteocalcin. Treatment with rhBMP-2 induced Clone K cells to differentiate into both osteoblasts and chondrocytes. These cells expressed mRNAs for Sox9 and aggrecan in addition to osteogenic markers. Culture in an adipogenic differentiation medium induced Clone K cells to differentiation into adipocytes, which expressed mRNAs for PPARgamma2 and a2P. Clone K cells cultured in a serum-depleted medium generated desmin-positive cells and expressed MyoD1 mRNA. Clone K cells exhibited numerous alpha-smooth muscle actin-positive cells; however, treatment with rhBMP-2 decreased their number. Clone K cells, transplanted with a carrier containing rhBMP-2 into the muscles of SCID mice, generated ectopic endochondral bone formation. In these tissues, several osteoblasts and chondrocytes expressed SV40 T antigen, indicating their Clone K cell origin. Thus, Clone K cells are useful tools for analyzing the characteristics of human multipotential mesenchymal progenitors.

Adipocytes↗

PubMed2004

Treatment strategy for Boerhaave's syndrome.

Esophageal rupture is a potentially mortal condition. Rapid and correct diagnosis, and urgent surgical treatment with esophagectomy is indicated, but conservative and other surgical treatments have also been reported recently. The treatment strategies for esophageal rupture are discussed here, based on our experiences with four cases during the last 10 years. They were admitted urgently and each was treated by a different method. Three of them underwent emergency operations, one undergoing primary closure of the ruptured esophagus, another received a T-tube insertion from the ruptured site with omental flap, and the third an esophagogastrectomy. The fourth case was treated conservatively. All patients survived and were discharged 36-144 days post treatment. One of them was readmitted for debridement of necrotic rib. In conclusion, the prompt and accurate diagnosis of esophageal rupture is crucial for a subsequent successful treatment. Conservative treatment or operation including esophagectomy will be determined by the severity of the condition.

Adult↗

PubMed2004

Effects of ageing and smoking on SP-A and SP-D levels in bronchoalveolar lavage fluid.

Surfactant protein (SP)-A and SP-D are collagen-like glycoproteins that are synthesised in the distal pulmonary epithelium. This study examined the effects of ageing and long-term smoking on SP-A and SP-D in the lungs. The possible links to the development of pulmonary emphysema were also investigated. Sequential lavage was performed in young and middle-aged or elderly nonsmokers and asymptomatic current smokers with various smoking histories. Middle-aged or elderly smokers were further categorised according to the presence of emphysema by high-resolution computed tomography. Levels of SP-A and SP-D in bronchial lavage (BL) fluid and in bronchoalveolar lavage (BAL) fluid were quantified by ELISA. Significant decreases in SP-A were seen with age in nonsmokers in BL fluid, but not in BAL fluid. Middle-aged or elderly smokers with emphysema had lower levels of SP-A in both BL and BAL fluids when compared with young subjects, and in BL fluid when compared with middle-aged or elderly smokers without emphysema. SP-D did not change with age alone, however, it was decreased in middle-aged or elderly smokers when compared with similarly aged nonsmokers. In conclusion, surfactant protein-A may decrease with age alone or due to the cumulative effects of long-term smoking and development of emphysema, while surfactant protein-D decreases due to long-term smoking.

Adolescent↗

PubMed2004

A case of thrombosis mimicking a buccal tumour: usefulness of MRI.

A rare case of thrombosis mimicking a tumour in the buccal region is reported. Since the entire round mass was located deeply, it was difficult to diagnose. Contrast computed tomography, magnetic resonance imaging (MRI) and ultrasound examinations may be useful, but MRI was most useful in this case because it allowed prediction of different kinds of histological structures in the soft tissue. The findings of T1 weighted imaging, T2 weighted imaging and examination with Gd-DTPA on T1 weighted imaging are useful for predicting the character of deeper soft tissue masses, and can differentiate thrombosis from lymphadenopathy, lipoma and other lesions.

Aged↗

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↗

PubMed2003

Prognostic factors in resection of pulmonary metastasis from colorectal cancer.

BACKGROUND: The aim of this retrospective study was to evaluate characteristics of primary colorectal cancer and pulmonary metastases in order to identify prognostic factors for overall survival and risk factors for further intrapulmonary recurrence after resection of pulmonary metastases from colorectal cancer. METHODS: Forty-nine patients who underwent resection of pulmonary metastases from colorectal cancer were reviewed. The factors assessed were age, sex, pathological findings of the original colorectal cancer (depth, lymphatic invasion, venous invasion, lymph node metastasis, differentiation, Dukes' stage) and pulmonary metastasis (maximum tumour size, number of tumours, completeness of resection), serum carcinoembryonic antigen level, previous hepatectomy for liver metastases, and surgical procedure for resection of pulmonary metastasis. Overall survival and intrapulmonary recurrence were also reviewed. RESULTS: Survival rates after resection of pulmonary metastases were 78 per cent at 3 years and 56 per cent at 5 years. Solitary pulmonary metastases were significantly correlated with survival (P = 0.049). The pathological features of the primary colorectal cancer had no impact on survival. Histologically incomplete resection of pulmonary metastasis significantly correlated with pulmonary re-recurrence (P = 0.034). CONCLUSION: Long-term survival can be expected after complete resection of pulmonary metastases arising from colorectal cancer, especially in patients with a solitary pulmonary metastasis.

Adult↗