Search PubMed⌕ Search

Biomedical subjects

M Masuda

Publications and source records attributed to M Masuda.

At least 181 records · Page 10Linked to original sources
PubMed1998

Dual action of CD30 antigen: anti-CD30 antibody induced apoptosis and interleukin-8 secretion in Ki-1 lymphoma cells.

CD30 is a member of the tumor necrosis factor superfamily. In this study, we examined the effect of four anti-CD30 (aCD30) antibodies (Abs) on CD30-positive anaplastic large cell lymphoma-derived cell line, Ki-JK. The aCD30 Abs suppressed [3H]thymidine (TdR) incorporation. With a TdT mediated dUTP-biotin nick end labeling method, apoptosis was detected in Ki-JK cells at day 5 after the addition of aCD30 Ab to the culture. Genistein, an inhibitor of protein tyrosine kinase, had no effect on aCD30 Ab-induced apoptosis. The aCD30 Ab simultaneously induced interleukin-8 (IL-8) secretion in the Ki-JK cells. In culture of the Ki-JK cells with aCD30 Ab for 5 days, the IL-8 concentration of the cell free-supernatant increased to 240 +/- 16 pg/ml, though the concentration was < 12.5 pg/ml without aCD30 Ab. In combination with aCD30 Ab, genistein decreased the concentration of IL-8 in day 5 supernatants. Although, doxorubicin and herbimycin-A suppressed [3H]TdR incorporation and induced apoptosis in the Ki-JK cells, they did not induce IL-8 secretion. Only aCD30 Ab-induced apoptosis was accompanied by IL-8 secretion. IL-8 mRNA was not detected in the Ki-JK cells by reverse transcription-polymerase chain reaction assay. IL-8 mRNA was detected 5 days after adding aCD30 Ab to the culture.

Antibodies↗
PubMed1998

Pharmacophore identification of a chemokine receptor (CXCR4) antagonist, T22 ([Tyr(5,12),Lys7]-polyphemusin II), which specifically blocks T cell-line-tropic HIV-1 infection.

We have previously found that T22 ([Tyr(5,12), Lys7]-polyphemusin II) has strong anti-human immunodeficiency virus (HIV) activity, and that T22 inhibits T cell-line-tropic HIV-1 infection mediated by CXCR4/fusin. T22 is an 18-residue peptide amide, which takes an antiparallel beta-sheet structure that is maintained by two disulfide bridges. Structure-activity relationship (SAR) studies on T22 have disclosed the contributions of each region of T22 to activity or cytotoxicity, and have provided the following useful information to develop new CXCR4 antagonists: The number of Arg residues in the N-terminal and C-terminal regions of T22 is closely related to anti-HIV activity. Addition of a variety of functional groups at the N-terminal end results in increases in activity. Disulfide rings, especially the major disulfide loop, are indispensable for anti-HIV activity and maintenance of the beta-sheet structure. Trp3 can be replaced by other aromatic residues (Tyr, Phe and L-2-naphthylalanine). Between two repeats of Tyr-Arg-Lys, which are a characteristic structure in T22, Tyr-Arg-Lys in the N-terminal portion is more closely associated with anti-HIV activity and maintenance of the beta-sheet structure. A positive charge in the side chain at the (i + 1) position of the beta-turn region is necessary for strong activity. Through these studies, we have found several compounds having higher selectivity indexes (50% cytotoxic concentration/50% effective concentration) than that of T22.

Amino Acid Sequence↗
PubMed1998

Isolation and contraction of the stress fiber.

Stress fibers were isolated from cultured human foreskin fibroblasts and bovine endothelial cells, and their contraction was demonstrated in vitro. Cells in culture dishes were first treated with a low-ionic-strength extraction solution and then further extracted using detergents. With gentle washes by pipetting, the nucleus and the apical part of cells were removed. The material on the culture dish was scraped, and the freed material was forced through a hypodermic needle and fractionated by sucrose gradient centrifugation. Isolated, free-floating stress fibers stained brightly with fluorescently labeled phalloidin. When stained with anti-alpha-actinin or anti-myosin, isolated stress fibers showed banded staining patterns. By electron microscopy, they consisted of bundles of microfilaments, and electron-dense areas were associated with them in a semiperiodic manner. By negative staining, isolated stress fibers often exhibited gentle twisting of microfilament bundles. Focal adhesion-associated proteins were also detected in the isolated stress fiber by both immunocytochemical and biochemical means. In the presence of Mg-ATP, isolated stress fibers shortened, on the average, to 23% of the initial length. The maximum velocity of shortening was several micrometers per second. Polystyrene beads on shortening isolated stress fibers rotated, indicating spiral contraction of stress fibers. Myosin regulatory light chain phosphorylation was detected in contracting stress fibers, and a myosin light chain kinase inhibitor, KT5926, inhibited isolated stress fiber contraction. Our study demonstrates that stress fibers can be isolated with no apparent loss of morphological features and that they are truly contractile organelle.

Actin Cytoskeleton↗
PubMed1998

Expression and characterization of dog CYP2D15 using baculovirus expression system.

Dog CYP2D15 was expressed in Sf9 cells with a recombinant baculovirus. Infection of Sf9 insect cells with a recombinant dog CYP2D15-virus resulted in the expression of a protein which cross-reacted with a polyclonal antibody against a dog CYP2D15-specific peptide. The difference spectrum of CO-complex of reduced P450 of the infected cell microsomes had a maximal absorbance at 449 nm. The specific content of P450 was calculated to be 0.56 nmol/mg of Sf9 cell microsomal protein. Although the expressed dog CYP2D15 showed high catalytic activity for the hydroxylations of bunitrolol and imipramine at low substrate concentration (10 microM), the catalytic activity for that of debrisoquine (50 microM) was extremely low as compared with that of CYP2D from other species. Dog liver microsomes also showed bunitrolol and imipramine hydroxylase activities, but not debrisoquine hydroxylase activity at the same substrate concentrations. In addition, the expressed CYP2D showed high catalytic activity for imipramine N-demethylation. Thus, our study reveals that the expressed dog CYP2D15 engages in high catalytic activity and has a unique substrate specificity from other CYP2D subfamilies. Western blot analysis suggested that the dog CYP2D15 contents were less than 4% of the total liver P450 content, assuming that 100% of expressed CYP2D15 incorporated heme.

Animals↗
PubMed1998

Prognostic significance of Ki-67, p53, and Bcl-2 expression in prostate cancer patients with lymph node metastases: a retrospective immunohistochemical analysis.

The prognostic significance of Ki-67, p53, and Bcl-2 expression was evaluated in prostate cancer patients with lymph node metastases. Immunohistochemical staining of archived material obtained from 56 patients was performed by the streptavidin-biotin method. Univariate survival analysis showed that a Ki-67 labeling index (Ki-67 LI) of > or = 8.4 in the primary tumor identified a group of patients with a significantly poorer prognosis (P < 0.001). furthermore, a Ki-67 LI of > or = 8.7 in the nodal metastatic tumor was also associated with a poorer prognosis (P < 0.01). Multivariate analysis showed that the Ki-67 LI of primary tumors (P < 0.01) and lymph node metastases (P < 0.01) had independent prognostic value. p53 and Bcl-2 expression had no prognostic value in patients with prostate cancer and lymph node involvement. The Ki-67 LI has more prognostic value than p53 and Bcl-2 expression for patients with prostate cancer that has spread to the lymph nodes.

Aged↗
PubMed1998

Clinical significance of interruption of therapy with allylestrenol in patients with benign prostatic hypertrophy.

BACKGROUND: A multicenter, clinical trial investigated the effects of an interruption of antiandrogen therapy on subjective and objective clinical parameters in patients with benign prostatic hypertrophy (BPH). METHODS: Patients were given antiandrogen therapy with allylestrenol (50 mg/day) for 16 weeks. The medication was then withheld and the patients were carefully monitored for an additional 16 weeks. There were 34 BPH patients ranging in age from 55 to 82 years (mean, 66.1 years). The efficacy of allylestrenol was evaluated by its effects on prostate volume, maximum urinary flow rate (MFR), and symptom scores at the end of 16 weeks of treatment and then again at 32 weeks (16 weeks after cessation of therapy). RESULTS: Allylestrenol was effective in the treatment of BPH, and was still effective 16 weeks after the cessation of medication. The prostate volume did not change after treatment cessation nor did the total symptom score, but the MFR reversed to the pretreatment level. Serum testosterone (1.95 ng/mL), dihydrotestosterone, and gonadotropin levels decreased on therapy, but were completely reversed by the end of this study. A prostate needle biopsy revealed that after 16 weeks without therapy, some glands showed regressive glandular changes, while some glands showed slight hyperplastic changes of the secretory epithelium. Eight per cent of patients complained of loss of libido during this study. CONCLUSIONS: Allylestrenol is an effective and safe medical treatment for patients with symptomatic BPH. Hormonal and histopathologic findings suggest that the prostate gland may regrow after discontinuation of medication.

Aged↗
PubMed1998

Inhibitory effect of central dopamine on basal pancreatic secretion in conscious rats.

We examined the role and the peripheral mechanism of action of central dopamine on basal pancreatic exocrine secretion in conscious rats. Rats were fitted with bile and pancreatic catheters to collect bile and pancreatic juice separately and also with a left lateral brain ventricle and external jugular vein catheters. After 90-min basal collection, the D1- and D2-receptor antagonists (Sch-23390 and eticlopride, respectively) and dopamine were administered into the lateral brain ventricle. Sch-23390 (30, 100, and 300 nmol/rat), but not eticlopride (300 nmol/rat), stimulated pancreatic fluid and protein secretion. Dopamine (30, 100, and 300 nmol/rat) inhibited pancreatic secretion lose dependently. Pretreatment with Sch-23390 prevented the inhibitory effect of dopamine. Intravenously injected Sch-23390 or dopamine had no effect on pancreatic secretion. The inhibitory effect of dopamine was blocked by bretylium, an inhibitor of norepinephrine release, and phentolamine, an alpha-blocker, but not by vagotomy. The beta-antagonist propranolol alone significantly inhibited basal pancreatic secretion, and dopamine did not modify the inhibitory effect of propranolol. The proton pump inhibitor omeprazole partially but not completely reduced the inhibition by dopamine. These results suggest that central dopamine inhibits pancreatic exocrine secretion via D1-like receptors and that the inhibitory effect is mediated via sympathetic nerves, especially alpha-adrenoceptors.

Animals↗
PubMed1998

Experimental study for the development of an in vitro test for contact allergens. 2. Comparison of the in vitro sensitization test with the guinea pig maximization test for contact allergens.

We have previously reported an in vitro hapten-specific sensitization method using Pam-212 cells (in vitro sensitization test) to identify the potential effectiveness of contact allergens. In the present study, we conducted comparison studies of 11 allergens and 2 irritants in order to evaluate the method as an alternative predictive test. The guinea pig maximization test (GPMT) was developed based on the test described by Magnusson and Kligman. Our assay was carried out as follows: we treated Pam-212 cells with 13 test chemical solutions, while T cells and macrophages of BALB/c mice were cultured with hapten-conjugated Pam-212 cells for 5 days. After incubation, 10(5) T cells were stimulated with mitomycin-C-treated spleen cells conjugated with chemicals. Three days later, the [3H]methyl thymidine incorporation was counted. The results of the GPMT were in agreement with those reported in previous studies except for benzocaine. In our GPMT experiments, benzocaine was negative, but it had been classified as a moderate sensitizer in previous studies. Our assay detected extreme, strong and moderate sensitizers as previously classified by the GPMT They could be summarized as follows: three of five chemicals classified as moderate sensitizers, and 100% of strong or extreme sensitizers were detected by both the GPMT and the in vitro sensitization test. No irritants showed a positive reaction in our assay. These results support the view that the sensitivity of our in vitro test may be equivalent to that of the GPMT and may be useful as a rapid and objective allergen screening test.

Allergens↗
PubMed1998

Prognostic significance of p53 protein overexpression in transitional cell carcinoma of the renal pelvis and ureter.

Fifty-three patients with invasive transitional cell carcinoma of the renal pelvis and ureter were studied for p53 protein overexpression by immunohistochemistry. Overexpression of p53 protein was observed in 19 patients (35.8%). There was a significant correlation between overexpression of p53 protein and histologic grade (p < 0.01). However, there was no correlation found between p53 immunoreactivity and pathologic stage. By univariate survival analysis, a significant difference in cumulative survival was observed between stage pT2 and stage pT3 or pT4 tumors (p < 0.05). The difference in survival between patients with p53-positive and negative tumors did not reach statistical significance (0.05 < p < 0.01). Multivariate analysis revealed that pathologic stage had an independent prognostic value (p < 0.05). The independent prognostic value of p53 protein overexpression did not quite reach statistical significance (p = 0.07). p53 protein nuclear overexpression appears to be a relatively weak prognostic indicator for patients with invasive transitional cell carcinoma of the renal pelvis and ureter.

Adult↗
PubMed1998

Pasteurella multocida toxin and Bordetella bronchiseptica dermonecrotizing toxin elicit similar effects on cultured cells by different mechanisms.

We compared the effects of Pasteurella multocida toxin (PMT) with Bordetella bronchiseptica dermonecrotizing toxin (DNT) at a cellular level under same conditions. Both PMT and DNT cause actin stress fiber formation in MC3T3-E1 cells which is known to be regulated by the small GTP-binding protein Rho. DNT induced mobility shifts of Rho on SDS-polyacrylamide gel electrophoresis, indicating direct modification as reported elsewhere. In contrast, no alternations in the electrophoretic mobility of Rho were found in lysates from PMT-treated cells. PMT but not DNT increased the intracellular level of inositol phosphates, indicating the elevation of phospholipase C (PLC) activity in the PMT-treated cells. These results indicate that PMT does not have Rho as a target but activates PLC. The formation of actin stress fiber by PMT seems to be stimulated through the indirect activation of Rho, which resides downstream of PLC, PMT and DNT seem to elicit similar toxic effects, at least in part, through the activation of Rho.

3T3 Cells↗
PubMed1998

Role of nitric oxide synthase in release of endothelin from cultured human endometrial cells.

The aim of this study was to investigate the influence of the nitric oxide/nitric oxide synthase (NO/NOS) system on the release of endothelin-1 (ET-1) in human endometrial cells. Human endometrial stromal cells in secretory phase were incubated for 72 h in serum-free RPMI 1640 medium in the absence or presence of different concentrations of interleukin-1beta (IL-1beta) and NG-monomethyl-L-arginine (LNMMA), a specific competitive inhibitor of NOS. ET-1 released from the cultured cells into the medium was determined by specific RIA. In all the experiments at various times, IL-1beta significantly increased the release of ET-1. LNMMA significantly attenuated the release of ET-1 when the cells were cultured with both IL-1beta and LNMMA, but LNMMA alone had no effect on ET-1 release. These results suggest that the NO/NOS system in human endometrium is involved in the regulation of ET-1 release via IL-1beta secretion. It can also be inferred that NO and ET-1 control the functions of endometrium in close association with IL-1beta.

Adult↗
PubMed1998

[Fine-needle aspiration cytology of tumors of major salivary glands].

Between 1986 and 1997, 124 patients with tumors of major salivary glands (93 parotid tumors, 31 submandibular gland tumors) were assessed by fine-needle aspiration cytology (FNAC). The 124 cases included 28 cases of primary malignant tumors and 96 cases of benign lesions. The preoperative fine-needle diagnoses were compared with postoperative pathologic findings. Sensitivity for malignancy was 64%, and specificity was 99%. Overall accuracy was 91%, and the predictive value for malignancy was 95%. FNAC allowed determination of histogenesis in 13 (68%) of the 19 cases cytologically diagnosed as malignant, and in 72 (71%) of the 105 cases cytologically diagnosed as benign. The diagnostic accuracy for histologic diagnosis of malignant neoplasms, pleomorphic adenoma, and Warthin's tumor was 46%, 73%, and 82%, respectively. The predictive value for specific histologic diagnosis of malignancy, pleomorphic adenoma, and Warthin's tumor was 100%, 91%, and 100%, respectively. The diagnostic accuracy and the predictive value for histologic diagnoses were relatively high (> 70%) for squamous cell carcinoma, adenocarcinoma, malignant lymphoma, pleomorphic adenoma, and Warthin's tumor. Adenoid cystic carcinoma and low-grade malignancies such as mucoepidermiod carcinoma and acinic cell carcinoma were the lesions most frequently misdiagnosed.

Adenocarcinoma↗
PubMed1998

[Cyclin D1 overexpression in laryngeal carcinomas].

Overexpression of cyclin D1 has been found in a variety of malignancies and is suggested to be related to tumor progression. We immunohistochemically investigated the overexpression of cyclin D1 protein in 92 laryngeal carcinomas. Twenty-eight (30.4%) of the carcinoma specimens showed overexpression of cyclin D1. This overexpression was not related to the tumor stage, lymph node metastasis, or clinical outcome. However, the overexpression of cyclin D1 in patients with local recurrence was significantly higher than in patients with no recurrence. Cyclin D1 immunohistochemical staining is considered to be a useful marker for predicting tumor recurrence.

Biomarkers, Tumor↗
PubMed1998

[Analysis of the prognostic factor in the patients with locally invasive bladder cancer who underwent total cystectomy].

OBJECTIVES: Prognosis and related factors were analysed as for the patients with locally invasive bladder cancer who underwent total cystectomy and pelvic lymph node dissection. METHODS: Between January 1977 and December 1996, a hundred and one patients with locally invasive bladder cancer underwent total cystectomy and pelvic lymph node dissection at University Hospital. Survival rates of these patients were calculated by Kaplan-Meier method and statistical significances were analysed by univariate and multivariate analyses. RESULTS: Most significant factor was PS at cystectomy and pN was next. Survival rate of the patients who underwent total cystectomy after 1988 showed significantly better than others. Thirteen patients achieved complete response by preoperative therapy. But, two of them who had positive nodes were died by cancer. CONCLUSION: Considering from these results, performance status at cystectomy and lymph node metastasis are predictable prognostic factor for locally invasive bladder cancer patients.

Adult↗
PubMed1998

[Reoperation after repair of complete transposition of the great arteries].

Atrial switch operation (Mustard operation, Senning operation). Rastelli operation, and arterial switch operation (Jatene operation) have been performed as definitive methods for the repair of complete transportation of the great arteries (TGA). Obstruction of the superior vena cavae and the pulmonary venous tract are common reasons for reoperation after the atrial switch operation. Stenosis of the extracardiac conduit is inevitable after the Rastelli operation is performed. Reconstruction of the right ventricular outflow tract using Danielson's procedures may eliminate the need for reoperation. The REV procedure at the time of initial operation may decrease the incidence of reoperation after the repair of TGA with a ventricular septal defect and left ventricular outflow tract obstruction. Pulmonary stenosis is the most common reason for reoperation after the arterial switch operation. Reconstruction of the pulmonary artery using pacifico's method or the single pantaloon patch technique with autologous pericardium is expected to reduce the occurrence rate of postoperative pulmonary stenosis. Postoperative aortic regurgitation is uncommon and is usually mild in grade. However, because the pulmonary sinus is shallow and fragile compared with the aortic sinus of Valsalva, the durability of neoaortic valves remains to be elucidated during long-term follow-up.

Aortic Valve Insufficiency↗
PubMed1998

[Long-term survival of bladder preservation therapy with radiation and chemotherapy for locally invasive bladder cancer].

The prognoses and prognostic factors of the 54 patients with locally invasive bladder cancer who underwent bladder preservation therapy at Yokohama City University Hospital between 1977 and 1995 were analyzed statistically. The therapeutic modalities of bladder preservation were mainly radiation or chemotherapy. The prognosis for the patients who underwent bladder preservation therapy was worse than that for the patients who underwent total cystectomy. The prognostic factors of these patients were size and grade of tumor, presence of hydronephrosis and performance status (PS) of the patients by univariate analysis. Tumor grade was the most predictable prognostic factor using multivariate analysis. Only 17 patients survived more than 5 years after treatment; 78% of the survivors had good PS (0 or 1). Five of them died of cancer and two patients were alive with cancer. All of them had G3 tumors. These results suggest that patients with locally invasive G2 tumor could be candidates for bladder preservation therapy and patients who underwent bladder preservation therapy should be evaluated at 10 years post-therapy.

Adult↗
PubMed1998

Effects of procollagen C-proteinase enhancer protein on the growth of cultured rat fibroblasts revealed by an excisable retroviral vector.

An excisable retroviral vector, TSN-lox, was developed by exploiting Cre-loxP homologous recombination. An integrated TSN-lox provirus could be excised, leaving a solo long terminal repeat at the integration site; inverse PCR, taking advantage of the solo long terminal repeat, was used to characterize cellular flanking sequences. A TSN-lox-transduced Rat2 cell clone, lox-7, was found to harbor the provirus in an intron of the procollagen C-proteinase enhancer protein (PCPE) gene, whose expression was lowered compared with that of the parental Rat2. When the vector provirus in lox-7 cells was excised, PCPE expression was elevated. The level of PCPE expression seemed to affect cell growth properties such as morphology, contact inhibition, and anchorage-independent growth. These results suggested that the excisable retroviral vector may be useful for studying the molecular basis for proviral insertion mutagenesis, and that PCPE may play a significant role in controlling cell growth and differentiation.

Animals↗