Biomedical subjects

Yuji Yamada

Publications and source records attributed to Yuji Yamada.

At least 19 recordsLinked to original sources

PubMed2006

Picosecond IR-UV pump-probe study on the vibrational relaxation of phenol-ethylene hydrogen-bonded cluster: difference of relaxation route/rate between the donor and the acceptor site excitations.

Picosecond time-resolved IR-UV pump-probe spectroscopy has been performed to study intracluster vibrational energy redistribution (ICVR) and vibrational predissociation (VP) for the OH and CH stretch vibrations of phenol-ethylene hydrogen-bonded cluster. The transient UV spectra after the picosecond IR pulse excitation of these modes were observed by 1+1 REMPI via S(1) with a picosecond UV pulse. We have focused on the difference of the energy flow routes and their rates between the donor (phenol) and the acceptor (ethylene) site. Though the transient UV spectra showed a similar broad feature for all the vibrations examined, the time profiles exhibited a remarkable site dependence, as well as substantial mode dependence. Especially, we found a large difference in the early stage of the IVR evolution and the rates, whereas the VP rates were very similar.

Journal Article↗

PubMed2006

Two cases of ganglioneuroma.

Although ganglioneuroma is a relatively rare tumor of the sympathetic nervous system, detection of this tumor has increased as imaging techniques such as computed tomography and ultrasonography have become prevalent. We report 2 cases of ganglioneuroma found incidentally. Both tumors were 40 to 60 mm in size. Magnetic resonance imaging in 1 patient showed a homogeneous mass with a low signal intensity on T1-weighted imaging and a heterogeneous mass with a high signal intensity on T2-weighted imaging, both characteristic of neurogenic tumor. Therefore, we performed laparoscopic adrenalectomy. Histopathologic examination demonstrated that one tumor was located on the adrenal medulla, with the other in the extra-adrenal retroperitoneal space.

Adrenal Gland Neoplasms↗

PubMed2006

Localized accumulation of angiotensin II and production of angiotensin-(1-7) in rat luteal cells and effects on steroidogenesis.

These studies aim to investigate subcellular distribution of angiotensin II (ANG II) in rat luteal cells, identify other bioactive angiotensin peptides, and investigate a role for angiotensin peptides in luteal steroidogenesis. Confocal microscopy showed ANG II distributed within the cytoplasm and nuclei of luteal cells. HPLC analysis showed peaks that eluted with the same retention times as ANG-(1-7), ANG II, and ANG III. Their relative concentrations were ANG II >or= ANG-(1-7) > ANG III, and accumulation was modulated by quinapril, an inhibitor of angiotensin-converting enzyme (ACE), Z-proprolinal (ZPP), an inhibitor of prolyl endopeptidase (PEP), and parachloromercurylsulfonic acid (PCMS), an inhibitor of sulfhydryl protease. Phenylmethylsulfonyl fluoride (PMSF), a serine protease inhibitor, did not affect peptide accumulation. Quinapril, ZPP, PCMS, and PMSF, as well as losartan and PD-123319, the angiotensin receptor type 1 (AT1) and type 2 (AT2) receptor antagonists, were used in progesterone production studies. ZPP significantly reduced luteinizing hormone (LH)-dependent progesterone production (P < 0.05). Quinapril plus ZPP had a greater inhibitory effect on LH-stimulated progesterone than either inhibitor alone, but this was not reversed by exogenous ANG II or ANG-(1-7). Both PCMS and PMSF acutely blocked LH-stimulated progesterone, and PCMS blocked LH-sensitive cAMP accumulation. Losartan inhibited progesterone production in permeabilized but not intact luteal cells and was reversed by ANG II. PD-123319 had no significant effect on luteal progesterone production in either intact or permeabilized cells. These data suggest that steroidogenesis may be modulated by angiotensin peptides that act in part through intracellular AT1 receptors.

Angiotensin I↗

PubMed2006

Radon-thoron discriminative measurements in Gansu Province, China, and their implication for dose estimates.

Indoor radon measurements were carried out in cave dwellings of the Chinese loess plateau in Gansu province, where previously the Laboratory of Industrial Hygiene (LIH), China, and the U.S. National Cancer Institute (NCI) had conducted an international collaborative epidemiological study. The LIH-NCI study showed an increased lung cancer risk due to high residential radon levels, and estimated the excess odds ratio at 100 Bq/m3 to be 0.19 (Wang et al., 2002). The present study used two types of newly developed passive monitors: One is a discriminative monitor for radon and thoron; the other is a selective monitor for thoron decay products. The arithmetic mean concentrations of indoor radon and thoron were 91 and 351 Bq/m3, respectively. As reported by our previous study in Shanxi and Shaanxi provinces (Tokonami et al., 2004), the presence of high thoron concentration was confirmed and thoron was predominant over radon in the cave dwellings. However, the mean equilibrium equivalent thoron concentration (EETC) was found to be much lower than expected when assuming the equilibrium factor of 0.1 provided by the UNSCEAR (2000) report. The effective dose by radon and thoron decay products was estimated to be 3.08 mSv/yr. It was significantly lower than the dose of 8.22 mSv/yr estimated from the measurements that did not take into consideration any discrimination between radon and thoron. Excess relative risk of lung cancer per sievert may be much higher than the risk estimated from the LIH-NCI study, considering that discriminative measurements were not used in their study.

Air Pollutants, Radioactive↗

PubMed2006

Feasibility and usefulness of high-dose chemotherapy (high-dose ifosfamide, carboplatin and etoposide) combined with peripheral blood stem cell transplantation for male germ cell tumor: a single-institute experience.

Although the usefulness of high-dose chemotherapy with peripheral blood stem cell transplantation for advanced germ cell tumor is still under evaluation in phase III randomized controlled studies, this approach is currently used as one treatment option for relapsed or advanced male germ cell tumor. Clinical outcomes of high-dose chemotherapy for a single institute from Japan are presented herein. We administered 63 courses of high-dose ifosfamide, carboplatin and etoposide chemotherapy (1250 mg/m carboplatin; 1500 mg/m etoposide; 7.5 g/m ifosfamide) to 34 men with germ cell tumors. Of these, 27 patients underwent high-dose ifosfamide, carboplatin and etoposide as first-line therapy after 2-3 courses of conventional bleomycin, etoposide and cisplatin chemotherapy, and seven patients underwent high-dose ifosfamide, carboplatin and etoposide for relapsed germ cell tumor. Peripheral blood stem cells were harvested during previous chemotherapy and sufficient CD34 cells were harvested for transplantation. Although all patients experienced grade 4 hemotoxicity, leukocyte counts recovered to above 1000/mul within 8-11 days after peripheral blood stem cell transplantation. No treatment-related deaths occurred. After a mean follow-up of 45 months (range 12-118 months), 23 of 34 patients (67.6%) remained disease-free. High-dose ifosfamide, carboplatin and etoposide could be performed safely, and could offer an effective means of treating advanced or refractory germ cell tumors in men.

Adolescent↗

PubMed2006

Hand-assisted laparoscopic radical nephrectomy using intraoperative ultrasonography for left renal cell carcinoma involving a level I renal vein tumor thrombus.

This report concerns two male patients, 65 (case 1) and 72 (case 2) years old, with a left renal tumor involving a level I renal vein tumor thrombus, who underwent hand-assisted laparoscopic radical nephrectomy using intraoperative ultrasonography. With the patient in the flank position, a midline supraumbilical hand port and two other ports were placed. Intraoperative ultrasonography identified the extent of the tumor thrombus. After hilar control, complete resection with intact removal was performed. Surgery lasted 305 min for case 1 and 237 min for case 2, with respective estimated blood loss of 410 mL and 572 mL. No postoperative complications occurred. Pathological examination showed a clear cell carcinoma with a level I tumor thrombus and negative surgical margins. Because the ultrasound probe can be easily inserted and the specimen can be extracted safely and intact, hand-assisted laparoscopic radical nephrectomy is practicable and effective for left renal cell carcinoma involving a level I renal vein tumor thrombus.

Aged↗

PubMed2006

A case of Sweet's syndrome following septic pulmonary emboli after high-dose chemotherapy for advanced testicular cancer.

A 33-year-old man with advanced testicular cancer underwent high-dose chemotherapy combined with peripheral blood stem cell transplantation. After administration of granulocyte colony-stimulating factor (G-CSF), multiple infiltrative erythema was identified on the face, thigh, and lower leg. A dermatologist diagnosed this as Sweet's syndrome caused by G-CSF; consequently G-CSF administration was stopped. When the skin lesions had improved, phlebitis was found at the injection site of the peripheral vein catheter. The patient then suffered from sudden left chest pain and dyspnea. Chest computed tomography showed the characteristic findings of septic pulmonary emboli (SPE). He was treated by the administration of vancomycin, fluconazole, and pazufloxacin mesilate. Although Sweet's syndrome and SPE are rare diseases, the presence of these diseases must be considered when performing chemotherapy for urological malignancy.

Adult↗

PubMed2006

Progress report on phase I/II clinical trial of Ad-OC-TK plus VAL therapy for metastatic or locally recurrent prostate cancer: Initial experience at Kobe University.

There is no effective therapy for hormone-refractory prostate cancer and a novel therapeutic modality, such as a gene therapy, should be actively pursued. Previously, Gardner and Chung conducted a phase I clinical trial of Ad-OC-TK (recombinant adenoviral vector containing osteocalcin promoter-driven herpes simplex virus thymidine kinase gene) plus VAL (valacyclovir) for the treatment of hormone-refractory prostate cancer at the University of Virginia. We report on our ongoing phase I/II clinical trial of Ad-OC-TK plus VAL for the treatment of advanced prostate cancer at the Kobe University Hospital, Japan.

Acyclovir↗

PubMed2006

High-dose chemotherapy for male germ cell tumor.

Today, 20-30% of male patients with advanced germ cell tumor (GCT) do not have durable, complete remission in spite of cis-platinum (CDDP)-based chemotherapy. High-dose chemotherapy (HDCT) has been tried in CDDP refractory GCT patients. Initially HDCT was performed with autologous bone marrow transplantation in heavily treated patients. However, the clinical outcome was not good and the treatment-related death rate was not ignorable. Therefore, earlier introduction of HDCT with peripheral blood stem cell transplantation was preferable as it renders HDCT more effective and less toxic, and multicycle HDCT is feasible. The durable free rate of recent HDCT for refractory GCT patients is 32-65%. HDCT is also performed as first line chemotherapy for poor prognosis GCT patients. Induction chemotherapy followed by multicycles of HDCT was tried. The durable free rate of recent HDCT as first line chemotherapy is 43-73%. Although previous reports suggest the superiority of HDCT, one recent randomized controlled trial (RCT) failed to show an improvement with one cycle of HDCT followed by three cycles of standard-dose chemotherapy (SDCT) compared with four cycles of SDCT. Ongoing RCT comparing multicycles of HDCT with SDCT for poor prognostic GCT patients will clarify the role of HDCT. Recently, new regimens of HDCT containing paclitaxel have been devised. In this review, the history, current status and future of HDCT for advanced or refractory GCT will be discussed.

Antineoplastic Agents↗

PubMed2006

Ectopic recurrence of craniopharyngioma.

A 27-year-old woman presented with ectopic recurrence manifesting as an asymptomatic mass in the left frontal convexity 5 years after subtotal removal of suprasellar craniopharyngioma through a right orbitozygomatic craniotomy. The mass had enlarged gradually over the next 5 years, so a second operation was performed for total removal. The histological diagnoses of both lesions were adamantinomatous type craniopharyngioma with MIB-1 indexes of 4.2% and 7.4%. The second lesion probably resulted from dissemination. Craniopharyngioma is a benign tumor, and ectopic recurrence is rare. Long-term clinical and neuroimaging follow up is recommended.

Adolescent↗

PubMed2006

[Pathological prognostic factors of renal pelvic and ureteral cancer].

OBJECTIVE: To determine the pathologic risk factors after nephroureterectomy in patients with urothelial carcinoma of the renal pelvis and ureter. PATIENTS AND METHODS: We investigated the clinicopathological features of 131 patients (94 males and 37 females) with urothelial carcinoma of the renal pelvis and ureter who underwent nephroureterectomy at our department and related facilities from August, 1994 to August, 1997. The mean age of the patients was 68 years, ranging from 24 to 86 years. RESULTS: The 1-, 3- and 5-year cause-specific survival rates (Kaplan-Meier's method) for all of the patients were 91.8%, 76.7%, and 67.8%, respectively. The significant prognostic factors for survival rates by univariate analysis using the log rank test were tumor stage, infiltration pattern, lymphatic invasion, vessel invasion and lymph node metastasis. On the other hand, multivariate analysis using Cox proportional hazards regression model showed the most influential prognostic factors to be vessel invasion and tumor stage. CONCLUSIONS: From these results, in urothelial carcinoma of the renal pelvis and ureter underwent nephroureterectomy, we suggested that vessel invasion and tumor stage were the independent prognostic factors.

Adult↗

PubMed2006

Clinical utility of serum macrophage migration inhibitory factor in men with prostate cancer as a novel biomarker of detection and disease progression.

Macrophage migration inhibitory factor (MIF) has been shown to play an important role in the growth and metastasis of prostate cancer. The objective of this study was to determine whether the serum level of MIF could be used as a diagnostic biomarker for prostate cancer as well as a predictor of disease progression. A total of 369 men who underwent systematic prostate biopsy from January 2000 to April 2004 and 30 healthy controls were included in this study. The serum MIF level was measured using an enzyme linked immunosorbent assay. Associations between the serum MIF level and several clinicopathological factors were analyzed. Among 359 patients, 137 were diagnosed as having prostate cancer. The mean values of serum MIF in the control, benign and cancer-groups were 2.1, 3.5 and 10.8 ng/ml, respectively. The MIF levels of patients with prostate cancer were significantly higher than those of the other two groups. A comparison of MIF and PSA values in all patients showed a positive correlation (correlation coefficient r(2)=0.56, p<0.0001). The MIF value in patients with prostate cancer was significantly associated with clinical T stage, Gleason score and percentage of positive biopsy core (PPBC). MIF levels in patients with metastasis were significantly elevated compared with those in patients without metastasis. Among patients undergoing radical prostatectomy, the level of MIF in those with pathologically confirmed extraprostatic disease was significantly higher than that in patients with organ-confined disease. Moreover, multivariate analysis showed that MIF values, PSA values and PPBC were independent predictors for extraprostatic disease. These findings suggest that an increased serum MIF level is closely associated with the progression of prostate cancer, and thus the serum MIF level could be useful as a novel biomarker for the detection of prostate cancer as well as a predictor of disease progression.

Adult↗

PubMed2006

[A case of retroperitoneal malignant peripheral nerve sheath tumor in a patient with neurofibromatosis].

We report a case of retroperitoneal malignant peripheral nerve sheath tumor (MPNST) in a patient with neurofibromatosis 1. A 42-year-old woman was admitted because of a palpable left abdominal mass. Her mother, son, and daughter had neurofibromatosis 1. Computed tomography and magnetic resonance imaging revealed a 73 x 76 mm retroperitoneal mass. We performed complete resection of the tumor, confirming the margin status by frozen section examination intraoperatively. The histopathological examination revealed MPNST. Although no further therapy was performed, she is alive with no evidence of disease 11 months after surgery.

Adult↗

PubMed2006

The up-regulation of type I interferon receptor gene plays a key role in hepatocellular carcinoma cells in the synergistic antiproliferative effect by 5-fluorouracil and interferon-alpha.

Combination therapy with interferon (IFN)-alpha and 5-fluorouracil (5-FU) has been reported to show an improved therapeutic efficacy in patients with advanced hepatocellular carcinoma (HCC) but the mechanism behind this has not been completely elucidated. We examined the molecular events underlying the antiproliferative effects of IFN-alpha and 5-FU in combination using six human HCC cell lines. When the antiproliferative effects of administering IFN-alpha and 5-FU together were analyzed using isobolograms, we found that the cell lines could be divided into two groups: the S-group containing three cell lines, which showed synergistic effects, and the A-group, containing the remaining three cell lines, which showed additive effects. Real-time RT-PCR and Western blot analyses revealed that the expression levels of type I IFN receptor subunits, IFNAR1 and IFNAR2, were specifically up-regulated by 5-FU in all three cell lines of the S-group with the exception of IFNAR2 in one cell line, but not in those of the A-group. IFN-alpha modulated the protein expression levels of six enzymes regulating sensitivity to 5-FU, but none of them were down- or up-regulated in the same way in all members of the S- or A-group. In conclusion, the 5-FU-induced modulation of IFN receptor expression could play a pivotal role in the therapeutic efficacy of IFN-alpha combined with 5-FU. Measuring the expression levels of IFN receptors, and their ability to be up-regulated, may be a promising method for selecting HCC patients for this type of combination therapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Picosecond IR-UV pump-probe spectroscopic study on the intramolecular vibrational energy redistribution of NH2 and CH stretching vibrations of jet-cooled aniline.

Intramolecular vibrational energy redistribution (IVR) of the NH2 symmetric and asymmetric stretching vibrations of jet-cooled aniline has been investigated by picosecond time-resolved IR-UV pump-probe spectroscopy. A picosecond IR laser pulse excited the NH2 symmetric or asymmetric stretching vibration of aniline in the electronic ground state and the subsequent time evolutions of the excited level as well as redistributed levels were observed by a picosecond UV pulse. The IVR lifetimes for symmetric and asymmetric stretches were obtained to be 18 and 34 ps, respectively. In addition, we obtained the direct evidence that IVR proceeds via two-step bath states; that is, the NH2 stretch energy first flows into the doorway state and the energy is further dissipated into dense bath states. The rate constants of the second step were estimated to be comparable to or slower than those of the first step IVR. The relaxation behavior was compared with that of IVR of the OH stretching vibration of phenol [Y. Yamada, T. Ebata, M. Kayano, and M. Mikami J. Chem. Phys. 120, 7400 (2004)]. We found that the second step IVR process of aniline is much slower than that of phenol, suggesting a large difference of the "doorway state increasing the dense bath states" anharmonic coupling strength between the two molecules. We also observed IVR of the CH stretching vibrations, which showed much faster IVR behavior than that of the NH2 stretches. The fast relaxation is described by the interference effect, which is caused by the coherent excitation of the quasistationary states.

Journal Article↗

PubMed2005

Development of a radon trap device using a corona discharge.

Radon is one of the noble gases, which are chemically inert and do not make any reactants under normal conditions. In this experiment we demonstrated an enigmatic reaction between radon and fluorine when a corona discharge is used as a promoter. Distinctive changes in radon concentrations were caused by the discharge and a trap efficiency of >99.5% was estimated. The mass balance between the trapped and the released radon was found to be reasonable. This indicates the existence of chemical reactions with radon. This trap phenomenon has application as a technique for reducing radon concentration in radon-contaminated air. It is possible that this technique will be applicable to other noble gases.

Air Pollutants, Radioactive↗

PubMed2005

Napthalimidobenzamide DB-51630: a novel DNA binding agent inducing p300 gene expression and exerting a potent anti-cancer activity.

Control of gene expression by small molecule compounds is a novel therapeutic strategy for cancer and usually it requires the presence of specific molecular recognition. The development of the compounds preferentially binding to the specific DNA sequence is one of the potential but very difficult approaches in this strategy. We designed and synthesized novel napthalimidobenzamide derivatives and analyzed their binding preferences to oligonucleotides by EtBr-displacement assay with DNA sequences, being essential fragments of the genes. To test whether these compounds modify the expression of specific genes, we analyzed the effect on the gene expression in AZ521 cells by differential display analysis using the compounds showing different characteristics in the recognition of specific DNA sequence. Among them, DB-51630, which showed approximately 350 times higher preferential binding to GC-repeats than to the AT and AA-repeating oligomers, caused the induction of a specific mRNA. The genetic sequence was identified to be the p300 gene by sequencing of the cloned cDNA. The p300 is a transcriptional co-activator protein that acts with other nuclear proteins in various cell differentiation and signal transduction pathways. This protein has intrinsic histone acetyltransferase activity and may act on chromatin directly to facilitate transcription. The increase of the amount of p300 mRNA increased after DB-51630 treatment by real time RT-PCR and Northern blot analysis. DB-51630 inhibited cell growth in various cancer cell lines at nanomolar range of concentrations, whereas p300 mRNA induction was observed at sub-nanomolar concentrations and the maximal induction occurred 8h after DB-51630 treatment. In contrast, anti-cancer drugs such as doxorubicin, vincristine, cisplatin, etoposide, and actinomycin D did not increase p300 transcription. DB-51630 revealed potent anti-cancer activity against human solid tumor xenografts. Thus, we demonstrated the anti-cancer activity of DB-51630, which interacts with a specific DNA sequence, thereby inducing p300 gene expression and exhibited significant anti-cancer activity in human tumor xenografts. Furthermore, such compounds that bind to specific DNA sequences may not only control the expression of specific genes but also exert other mechanisms in the anti-cancer effect than those of classical DNA binding drugs.

Antineoplastic Agents↗

PubMed2005

A novel cinnamic acid derivative that inhibits Cdc25 dual-specificity phosphatase activity.

The Cdc25 dual-specificity phosphatases are key regulators of cell cycle progression through activation of cyclin-dependent kinases (Cdk). Three homologs exist in humans: Cdc25A, Cdc25B, and Cdc25C. Cdc25A and Cdc25B have oncogenic properties and are overexpressed in some types of tumors. Compounds that inhibit Cdc25 dual-specificity phosphatase activity might thus be potent anticancer agents. We screened several hundred compounds in a library using an in vitro phosphatase assay, with colorimetric measurement of the conversion of p-nitrophenyl phosphate (pNPP) to p-nitrophenol by the catalytic domain of recombinant human Cdc25, and discovered TPY-835, which inhibits Cdc25A and Cdc25B activity (IC50 = 5.1 and 5.7 microM, respectively). TPY-835 had mixed inhibition kinetics for Cdc25A and Cdc25B. TPY-835 caused cell cycle arrest in the G1 phase in human lung cancer cells (A549 and SBC-5) but not cell cycle arrest in the G2/M phase. After treatment with TPY-835, the activation of Cdk2 was suppressed and phosphorylation of the retinoblastoma (Rb) protein was decreased in SBC-5 cells. In addition, TPY-835 induced an increase of the sub-G1 phase cell population after 48-72 h treatment. The growth inhibitory effects of TPY-835 against cisplatin (CDDP)-, camptothecin- and 5-FU-resistant cell lines are comparable to the growth inhibitory effect on their parental lines, thus indicating that TPY-835 did not show cross-resistance to these cell lines. These results suggest that TPY-835 is a promising candidate for constructing a novel class of antitumor agents that can control the cell cycle progression of cancer cells.

Cell Cycle Proteins↗