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Biomedical subjects

Y Osada

Publications and source records attributed to Y Osada.

At least 55 records · Page 3Linked to original sources
PubMed1997

The B cell epitope of paramyosin recognized by a protective monoclonal IgE antibody to Schistosoma japonicum.

Passive immunization of mice with a monoclonal IgE antibody to Schistosoma japonicum (SJ18 epsilon. 1) induces significant protection to a challenge infection and the target molecule of SJ18 epsilon. 1 is paramyosin. In the present study, we demonstrate the B cell epitope of paramyosin recognized by SJ18 epsilon. 1 by using a series of deletion mutants expressed in Escherichia coli. SJ18 epsilon 1 reacted with the recombinant paramyosin containing 113 amino acids (Glu301. Ala413) but not with a shorter peptide (Glu301-Asp343). Further epitope mapping carried out by a multi-pin system using heptameric peptides synthesized sequentially from 71 amino acids of paramyosin (Asp343-Ala413) demonstrated significant binding of SJ18 epsilon. 1 to the sequence, 359Ile-Arg-Arg-Ala362. Replacement set analysis of the pentameric peptide, 358Leu-Ile-Arg-Arg-Ala362, revealed that replacement of each residue with a hydrophobic or hydrophilic amino acid did not inhibit binding of SJ18 epsilon. 1, whereas replacement of positively charged Arg. or hydrophobic Ala with a negatively charged amino acid, Glu, showed reduction in binding of the antibody. Moreover, replacement of each amino acid including Arg with a positively charged amino acid, Lys, resulted in a drastic loss of the binding, indicating that binding of the antibody was markedly affected by the change of charges of the peptide as well as by the conformational alteration. The target epitope of SJ18 epsilon. 1 was common among paramyosins of S. mansoni, Taenia solium and Echinococcus granulosus but not among nematode paramyosins, suggesting that the epitope is specific for platyhelminthes.

Amino Acid Sequence↗
PubMed1997

Electroresponsive pulsatile depot delivery of insulin from poly(dimethylaminopropylacrylamide) gel in rats.

We describe a model for pulsatile drug delivery with an electroresponsive polymer that is stimulated by an externally applied electrical field. Insulin loaded in an electroresponsive poly(dimethylaminopropylacrylamide) (PDMAPAA) gel was administered as a subcutaneous depot in rats. The gel induced a pulsatile plasma glucose decrease in correspondence to stimulation with a constant current of 1.0 mA (0.36 mA/cm2). The first drop occurred at 0.5 h after a 1-min application of current at 0 h and the second drop occurred at 3 h after a 10-min application of current at 2 h. Calculation of pharmacological bioavailability showed that the gel released 0.12% of the loaded insulin after these two stimuli. This in vivo study demonstrates the feasibility of this pulsatile delivery system. The mechanism of insulin release from the electroresponsive PDMAPAA gel is associated with electrokinetic flow of solvated insulin with water; that is, transportation process of counterions (electrophoresis) and water molecules (electroosmosis) in the crosslinked polyelectrolyte gel network.

Acrylic Resins↗
PubMed1997

Postoperative UFT adjuvant and the risk factors for recurrence in renal cell carcinoma: a long-term follow-up study. Kyushu University Urological Oncology Group.

BACKGROUND: Radical nephrectomy is the standard therapy for low-stage renal cell carcinoma. However, recurrence sometimes develops even in patients who are considered to have undergone a curative resection of the primary tumor. The purpose of this study was to evaluate the usefulness of UFT (a 1:4 mixture of tegafur and uracil) adjuvant and the risk factors for recurrence in renal cell carcinoma. METHODS: A prospective randomized trial was conducted to compare the use of long-term oral UFT adjuvant with nonadjuvant therapy after a radical nephrectomy for Robson stage I or II renal cell carcinoma. A multivariate analysis was also performed to estimate the risk factors for recurrence. RESULTS: A total of 71 patients were entered into this study, and 66 were evaluable (33 for each group). There was no significant difference in patient characteristics between the 2 groups. The nonrecurrence rate at 5 years after a radical nephrectomy was 80.5% and 77.1% in the UFT adjuvant group and the nonadjuvant group, respectively, with a median follow-up of 112.9 months; the difference was not significant. The toxicity of UFT was generally mild and tolerable. The tumor grade was found to be an important factor influencing recurrence. CONCLUSION: UFT cannot be universally recommended as an adjuvant therapy for radical nephrectomy in all patients with low-stage renal cell carcinoma.

Antimetabolites, Antineoplastic↗
PubMed1997

Significance of the preoperative intravesical instillation of doxorubicin and the oral administration of 5-fluorouracil in preventing recurrence after a transurethral resection of superficial bladder cancer. Kyushu University Urological Oncology Group.

BACKGROUND: The postoperative intravesical instillation of doxorubicin (ADM) has a preventative effect on recurrence after a transurethral resection (TUR) of superficial bladder cancer. However, the significance of preoperative ADM instillation remains unclear. Although the oral administration of 5-fluorouracil (5-FU) has been observed to show some clinical response against bladder cancer, its preventative effect on the recurrence of superficial bladder cancer after TUR is unknown. METHODS: Patients were randomized into 4 groups. All 4 groups received postoperative ADM instillation. In addition, patients in groups C and D received preoperative ADM instillation, whereas patients in groups B and D additionally received oral 5-FU postoperatively. The nonrecurrence rate and side effects were both compared among the 4 groups. RESULTS: Of the 282 patients registered, 200 were evaluable, with a median follow-up period of 21.4 months. There were no significant differences in the characteristics of the patients among the 4 groups. Group C (pre- and postoperative ADM) showed a significantly longer disease-free interval than group A (postoperative ADM alone). However, there was no significant difference in the disease-free interval between groups A and B (postoperative ADM plus 5-FU), or between groups C and D (pre- and postoperative ADM plus 5-FU). Bladder irritation symptoms were the most frequently noted side effect encountered in all groups, but the severity was generally mild. CONCLUSIONS: Preoperative ADM instillation was found to prevent recurrence to a greater extent than the usual postoperative instillation alone, whereas oral 5-FU was found to have no additional beneficial effect on the disease-free interval in patients with superficial bladder cancer.

Administration, Intravesical↗
PubMed1997

Comparative studies on schistosomulicidal activity of mouse and rat eosinophils.

Eosinophils from interleukin (IL)-5 transgenic mice were shown to have antibody-dependent killing activity against the larvae of Schistosoma japonicum. However, in comparison with rat eosinophils, the schistosomulicidal activity of mouse eosinophils was lower. Flow cytometric analysis of the cells binding to mouse immunoglobulins demonstrated that rat cells were superior to mouse cells in the binding of mouse IgG. However, the adherence and schistosomulicidal activity of mouse cells were inhibited by rat anti-mouse Fcgamma receptor monoclonal antibody. These results suggest that the mechanism of killing by mouse eosinophils is mediated by IgG antibodies.

Animals↗
PubMed1997

Protective roles of eosinophils in Nippostrongylus brasiliensis infection.

Nippostrongylus brasiliensis infection is characterized by blood and tissue eosinophilia induced by interleukin (IL)-5 secreted from CD4+ T cells. However, it is still obscure whether eosinophils play an important role in the protection against N. brasiliensis infection. In this study we attempted to determine whether the in vivo environment of IL-5 transgenic mice, characterized by high eosinophil production, could affect the worm burden after N. brasiliensis infection. Kinetic studies on the infection demonstrated a significantly lower worm recovery from the intestine of IL-5 transgenic mice compared to age-matched background controls. This tendency was also observed at the lung stage of the infection. Furthermore, with respect to elevation of the serum IgE concentration, the peak level was observed at 2 weeks after infection in infected background control mice with four times higher concentrations than those of uninfected mice. In contrast, the increase of IgE concentration in IL-5 transgenic mice was very limited and low. The adoptive transfer of eosinophils from IL-5 transgenic mice into background control animals resulted in the reduction of worm recovery from the lungs, suggesting that eosinophils play a key role in the protection against migrating larvae of N. brasiliensis. These results indicate that the innate high level of eosinophils due to constitutive production of IL-5 augments immunity against N. brasiliensis infection.

Adoptive Transfer↗
PubMed1996

Prognostic value of urokinase-type plasminogen activator in patients with superficial bladder cancer.

OBJECTIVES: A number of studies have demonstrated that urokinase-type plasminogen activator (u-PA) is one of the major enzymes in the development of cancer invasion and metastasis. We examined the possibility that u-PA content is an independent prognostic marker for superficial bladder cancer. METHODS: The u-PA content was estimated in superficial bladder cancer from 52 patients undergoing transurethral resection for the first time. The survival rates of the patients were calculated and the prognostic values for u-PA content (less than 8 ng/mg protein versus more than 8 ng/mg), Stage (pTa or pT1), grade (1 and 2 versus 3), number (single versus multiple), and size (less than 1 cm versus more than 1 cm) of tumor were determined by a multivariate regression model. RESULTS: Development of cancer invasion and metastasis was observed in 3 and 8 patients, respectively. The survival rate of the patients with high u-PA content was significantly lower than those with low u-PA content (P < 0.005). In the multivariate regression analysis, u-PA content was the most important risk factor for the prognosis, compared with the other factors: tumor stage, grade, multiplicity, and size. CONCLUSIONS: We have first shown that u-PA content is a new independent prognostic marker in patients with superficial bladder cancer.

Aged↗
PubMed1996

Comparison of DNA fingerprinting by PFGE and PCR-RFLP of the coagulase gene to distinguish MRSA isolates.

Staphylococcus aureus isolates were collected from epidemiologically unrelated clinical sources in Japan between 1991 and 1993. A total of 40 isolates, five each of eight coagulase types, were analysed by polymerase chain reaction (PCR) of the coagulase gene, PCR-restriction fragment length polymorphism (RFLP) after AluI digestion, and pulsed-field gel electrophoresis (PFGE) of chromosomal DNA after SmaI digestion. The efficiency of discrimination among the isolates increased in the order of PCR < PCR-RFLP < PFGE, yielding five, 13 and 31 different types, respectively. To assess the clinical use of these methods, 42 additional methicillin-resistant S. aureus (MRSA) isolates collected from 27 inpatients in a hospital were analysed. PFGE and PCR-RFLP were able to discriminate 11 and four types, respectively. PFGE analysis detected cross-infection between four postoperative patients in an intensive-care unit, and in six neonates in intensive care. We conclude that of the three methods tested, PFGE analysis currently allows the most effective discrimination of MRSA strains.

Bacterial Typing Techniques↗
PubMed1996

[Indication for surgery of pediatric testicular and funicular hydroceles in view of natural course].

PURPOSE: The purpose of this study is to confirm the definite indication for surgery of pediatric testicular and funicular hydroceles in view of natural course. METHODS: During the period from 1978 to 1994, we encountered 160 hydroceles in 149 pediatric patients. Patients ages ranged from 5 days after birth to 13 years and the mean follow-up periods was 4.7 years. We investigated the indication for surgery of pediatric hydroceles in six points of view: value of an aspiration of hydroceles, of what testicular or funicular or both, communication, size, age and testicular development. RESULTS: Nevertheless, of 160 hydroceles, 66 (41%) were performed an aspiration of hydroceles, the aspiration of hydrocele was ineffective in the majority of patients. Common hydroceles in neonates and infants required no specific treatment, as the majority of hydrocele resolve spontaneously, however surgical treatment was required for a communicating large hydrocele that had been often attacked by aspiration and appeared at older age. Funicular hydroceles were more difficult to spontaneous healing. Ipsilateral testis manifests a well-developed comparing control material. CONCLUSION: The indication for surgery of pediatric hydroceles were as follows: 1) hydroceles complicated by a inguinal hernia or cryptorchidism, 2) hydroceles appeared at older age and not resolved during 2-3 years over, 3) giant communicating funicular and testicular hydroceles present with an/hindrance for daily life.

Child↗
PubMed1996

[Clinical management of hypertension in patients with pheochromocytoma].

Surgical treatment of 18 tumors in 17 patients with pheochromocytoma, containing unsynchronous bilateral adrenal tumors, was performed at our department between 1978 and 1995. As an index of management of hypertension before and after surgery, maximum systolic blood pressure except critical region (more than mean + 2 SD) was used in this study. As an index of control of blood pressure during surgery, the difference between maximum and minimum systolic blood pressure during palpating tumor was also adopted. The index before surgery was closely correlated with the index in surgery (R = 0.646, P = 0.0038); maximum systolic blood pressure before surgery was a useful index forecasting the variation of blood pressure in surgery. The management of blood pressure before surgery was the most difficult in the group with sustained hypertension with superimposed paroxysms. After surgery, 2 patients without hypertension before surgery had hypotension, 2 others remained hypertensive and the others had normal blood pressure. Our findings indicated that the index of management of hypertension before surgery used in this study was a simple, noninvasive and important marker for variation of blood pressure in surgery.

Adolescent↗
PubMed1995

Cloning of the cDNA encoding a novel rat mast-cell proteinase, rMCP-3, and its expression in comparison with other rat mast-cell proteinases.

A cDNA encoding a novel rat mast-cell proteinase (MCP) named rMCP-3 was successfully cloned and sequenced from the peritoneal cells of Lewis rats infected with the intestinal nematode Nippostrongylus brasiliensis by using the combination of reverse transcription-PCR and rapid-amplification-of-cDNA-ends ('RACE') methods. The cDNA was 979 bp long and included a 741 bp open reading frame. When the deduced amino acid sequence was compared with those of other known mast-cell proteinases, rMCP-3 was considered to be translated as a preproenzyme with a 19-amino-acid signal peptide, a two-amino-acid activation peptide and a 226-amino-acid mature enzyme. The amino acid identity in the mature enzyme was 52.9% and 55.1% with rMCP-1 and rMCP-2 respectively. The rMCP-3 mRNA was not detected in the peritoneal cells of mast-cell-deficient Ws/Ws rats, though it was strongly detected in those of littermate +/+ and Lewis rats, indicating the mast-cell origin of rMCP-3 In addition to being present in peritoneal mast cells, the rMCP-3 mRNA was strongly detected in the skin, tongue, and RBL2H3 rat basophilic leukaemia cells and weakly in the jejunum of N. brasiliensis-infected rats by RNA blot analysis using a rMCP-3 gene-specific probe. By reverse transcription-PCR, the rMCP-3 mRNA was also detected in the lung. While the expression of rMCP-1 and rMCP-2 are clearly restricted in connective-tissue mast cells and mucosal mast cells respectively, rMCP-3 was widely expressed in both types of mast cells with a predominance in connective-tissue mast cells.

Amino Acid Sequence↗
PubMed1995

Effects of suramin on metastatic ability, proliferation, and production of urokinase-type plasminogen activator and plasminogen activator inhibitor type 2 in human renal cell carcinoma cell line SN12C-PM6.

Effects of suramin, a polysulfonated naphthylurea compound, on metastatic ability, proliferation, and production of plasminogen activators and plasminogen activator inhibitors were studied using the highly metastatic human renal cell carcinoma cell line, SN12C-PM6. After renal subscapular implantation of tumor cells in nude mice, suramin significantly inhibited metastasis of tumor cells to the lungs and liver. In vitro growth of tumour cells was inhibited by suramin in a dose-dependent manner, at relatively low doses (ID50 = 105 micrograms/ml). Plasminogen activator inhibitor type 2 (PAI-2) production by tumor cells was enhanced by suramin (100 micrograms/ml), whereas urokinase-type plasminogen activator (uPA) production was suppressed. Thus, the increase in PAI-2 and the decrease in uPA production correlated with the inhibitory effects on tumour growth and metastasis by suramin. Therefore suramin may be beneficial for the treatment of patients with an early stage of renal cancer with potential risk of metastasis.

Animals↗
PubMed1995

cDNA sequencing and expression of rat mast cell tryptase.

A cDNA encoding rat mast cell tryptase (rMCT) was successfully cloned, and sequenced, from peritoneal cells of Lewis rats infected with Nippostrongylus brasiliensis by the reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends methods. The cDNA was 1,097 base-pairs long, and included 822 base-pairs of an open reading frame. As judged from the deduced amino acid sequence, rMCT is highly homologous to mouse mast cell protease-6, and is considered to be translated as a prepro-enzyme with a 19-amino acid signal peptide, a 10-amino acid activation peptide, and a 245-amino acid mature enzyme. The rMCT mRNA was not detected in peritoneal cells of mast cell-deficient Ws/Ws rats, though it was strongly detected in ones of littermate +/+ and Lewis rats. In addition to in peritoneal mast cells, the rMCT mRNA was detected in the tongue. However, mRNA signals were not detected in the small intestine regardless of N. brasiliensis infection. Nor were mRNA signals detected in RBL2H3 rat basophilic leukemia cells. In the lung, the rMCT mRNA was strongly detected after infection with N. brasiliensis, though it was only faintly detected before infection. These results suggest that the rMCT is basically specific for connective tissue mast cells, but not for mucosal mast cells and that it is up-regulated in the lung during the inflammatory process of a parasitic infection.

Amino Acid Sequence↗
PubMed1995

Cloning of multidrug resistance gene pqrA from Proteus vulgaris.

The multiple antibiotic resistance gene pqrA was cloned from the chromosomal DNA of a clinical isolate of Proteus vulgaris 881051 into Escherichia coli KY2563. The MICs of quinolones tetracycline, cephalosporin, and chloramphenicol for transformant strain DNS7020 were from 8 to 32 times higher than those for the parent strain, KY2563. The level of expression of outer membrane protein F (OmpF) by DNS7020 was lower than that of KY2563 but not as low as that of an OmpF-deficient control strain. The 1.4-kb fragment containing the pqrA gene had an open reading frame encoding a polypeptide of 122 amino acid residues with a molecular weight of about 14,000, which was consistent with the experimental value identified by the Maxicell method. The putative PqrA polypeptide showed significant amino acid sequence similarity to the E. coli proteins SoxS and MarA. These polypeptides are strongly conserved in predicted helix-turn-helix DNA binding domains. The MarA protein, which is responsible for multiple antibiotic resistance in E. coli, also decreases OmpF expression. Moreover, the SoxS protein, which is characterized as a superoxide response regulon of E. coli, has also been shown to increase resistance to many structurally unrelated antibiotics. The soxS gene increases superoxide dismutase levels in addition to decreasing OmpF expression. The expression level of superoxide dismutase with DNS7020 was about 1.5 times higher than that with KY2563. These findings suggest that the pqrA gene in P. vulgaris confers multidrug resistance in a way similar to that of the soxS and marA genes in E. coli.

Amino Acid Sequence↗