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Biomedical subjects

Y Namiki

Publications and source records attributed to Y Namiki.

At least 19 recordsLinked to original sources
PubMed1998

Gene transduction for disseminated intraperitoneal tumor using cationic liposomes containing non-histone chromatin proteins: cationic liposomal gene therapy of carcinomatosa.

Cationic liposome-mediated gene therapy of cancer has been examined in a disseminated intraperitoneal tumor model. A combination of the strong CAG promoter-enhancer unit and high mobility group 1,2 (HMG-1,2) proteins has been used to improve transfection efficiency. The optimal deoxyribonucleic acid (DNA) and HMG-1,2 concentration ratio was determined in in vitro studies. Subsequently, we administered the liposome-DNA-HMG-1,2 complex intraperitoneally to tumor bearing nude mice and defined the most efficient concentration of liposomes. Using this approach, the median survival of tumor bearing nude mice was prolonged by the administration of a human tumor necrosis factor-alpha (TNF-alpha) gene inserted into a eukaryotic strong expression vector (pcagTNF-alpha) and exogenously added interferon-gamma (INF-gamma) (72 +/- 3 days: mean +/- s.e.). By contrast, survival was 36 +/- 3, 39 +/- 3 and 46 +/- 4 days in group receiving the TNF-alpha gene inserted in the reverse orientation (pcagTNF-alpha R) and normal saline (NS), pcagTNF-alpha R and INF-gamma and pcagTNF-alpha and NS, respectively. These results demonstrate an efficient approach for gene therapy of disseminated intraperitoneal cancer.

Animals↗
PubMed1998

[Mediastinal neurilemmoma originating in the right phrenic nerve: a case report].

We report on a 31-year-old man with a mediastinal neurilemmoma originating in the right phrenic nerve. The patient was admitted because of abnormal chest X-ray shadows observed during a routine checkup. A preoperative diagnosis of bronchial cyst in the mediastinum was made. The tumor was resected by video-assisted thoracic surgery. It was 3 x 4 x 3 cm in size, weighted 15 g, and originated in the right phrenic nerve. The histopathologic diagnosis was mediastinal neurilemmoma. Only 14 cases have been reported in the Japanese literature.

Adult↗
PubMed1997

Induction of the suicide HSV-TK gene by activation of the Egr-1 promoter with radioisotopes.

In investigating new methods for the treatment of pancreatic cancer, we have explored the possibility of using a combination of radiation and gene therapies. We demonstrate herein that the early growth response gene 1 promoter (Egr-1) is sufficient to confer selective expression of the luciferase gene (Luc) in a human pancreatic tumor cell line (AsPc-1) when exposed to ionizing radiation. The Egr-1 promoter directed the radioinducible expression of luciferase, and yielded higher levels of Luc activity than that in nonirradiated lines. The radioisotopes Tc-99m, I-131, and Ga-67-citrate were selected as Egr-1 activators for their potential to accumulate in tumors. We studied Ga-67-citrate, a radioisotope employed in tumor scintigraphy, for its suitability for selective gene induction. The plasmid vector pEgr-1-Luc was transfected into AsPc-1 cells and then exposed to radioisotopes. Luciferase activity increased by 100-300 times over control. We also inserted the herpes thymidine kinase gene (TK) downstream of Egr-1 and transfected this construct into AsPc-1 cells. Ga-67-citrate and ganciclovir were added to the cells and cell survival was assessed by MTT assay. The growth of AsPc-1 cells transfected with the pEgr-TK construct was suppressed 2 days after exposure of the cells to Ga-67-citrate. The results indicate that Ga-67-citrate may be useful in combining radiation and gene therapies.

DNA-Binding Proteins↗
PubMed1997

Effect of water content in perchloric acid on the non-aqueous potentiometric titration of nitrogen-containing compounds.

In the United States Pharmacopeia (USP), 0.1 N perchloric acid in acetic acid volumetric solution (hereafter HClO4 VS) used for non-aqueous titration has specified a water content between 0.02 and 0.05%. Preparing this titrant with such a narrow range of water content is very time consuming, precludes the use of commercially available titrants, and, consequently, prompted an investigation to try and expand the range up to 0.5%. In this study, the titrimetric results obtained using HClO4 VS containing more water were very close to those obtained using the USP specified titrants. A maximum assay difference of 0.7% in the titrations of three selected nitrogen-containing compounds, clonidine hydrochloride, dipyridamole, and adenosine were observed. The titrimetric results obtained using these titrants were also precise with RSDs of not more than 0.4%. Therefore, a wider range of water content in HClO4 VS between 0.02 and 0.5% is suggested for the USP potentiometric titration of nitrogen-containing compounds.

Indicators and Reagents↗
PubMed1996

Evaluation of three individual glucosyltransferases produced by Streptococcus mutans using monoclonal antibodies.

We previously established murine hybridomas producing a monoclonal antibody monospecific against three glucosyltransferases (I, SI and S) of Streptococcus mutans which contribute to dental caries formation. Here, we developed a new immunochemical technique (cross-dot system) with which individual levels of glucosyltransferases expressed by S. mutans can be evaluated. We also examined glucosyltransferase production and in vitro artificial plaque formation by a reference strain and several clinical isolates of S. mutans. The findings indicate that the levels of glucosyltransferases produced greatly vary with the cells and the culture medium, and that the cells producing high levels of both glucosyltransferase-SI and glucosyltransferase-I enzymes may possess high in vitro artificial plaque forming ability. We suggest that the cross-dot system will be useful for estimating the cariogenic potential of S. mutans isolates.

Antibodies, Monoclonal↗
PubMed1996

Method development for the determination of cefdinir and its related substances by high-performance liquid chromatography.

The validation of the HPLC method used for the determination of cefdinir and its related substances is described. The developed method was specific and stability-indicating and provided a linear response with concentration. The system and method precision, expressed as relative standard deviations, were not greater than 1%, and the reproducibilities within and between laboratories were acceptable for the assay method. The procedure can quantitate related substances greater than approximately 0.05% of the principal cefdinir peak.

Calibration↗
PubMed1996

Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution. 1.

Hydrolytic degradation products of cefdinir were studied in acidic (pH 1), neutral (pH 6), and basic (pH 9) solutions. Seven major degradation products were isolated by preparative and/or high-performance liquid chromatography and characterized by UV, IR, 1H-NMR, and mass spectra. To clarify degradation pathways in each pH solution, kinetic and product analyses during hydrolysis of cefdinir were carried out along with the followup reaction of representative degradation products. Cefdinir was shown to degrade via two major degradation routes: beta-lactam ring-opening and pH-dependent isomerizations (lactonization, epimerization at C-6 or C-7, syn-anti isomerization of N-oxime function).

Administration, Oral↗
PubMed1996

Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution. 2. Hydrolytic degradation pathway and mechanism for beta-lactam ring opened lactones.

Hydrolysis of cefdinir leads to pH-dependent isomerizations and beta-lactam ring-opening. Lactam ring opened gamma-lactones were produced as a mixture of four diastereoisomers based on the lactone methyl, and C-6 isomerizations in acidic to neutral solutions. Cefdinir and its 7-epimer were hydrolyzed to clarify the pathway leading to these lactones and the mechanism of C-6 epimerization with the aid of chiral separation techniques. Chiral separation using a bovine serum albumin column was employed to detect the beta-lactam ring opened products of cefdinir and its 7-epimer; the C-6 and C-7 isomerization was thereby observed; however, it was found to be pH-dependent at pH > or = 9. Optical activity detection applied to the lactones produced from cefdinir and its 7-epimer demonstrated that the corresponding peaks of these lactones were enantiomeric pairs. In addition, the smallest rate constant at pH 4 was observed for C-6 epimerization of the lactones, and it was found to proceed without deprotonation at C-6 by 1H-NMR spectroscopy. From the results of these studies, a plausible mechanism for C-6 epimerization has been proposed. Additionally, it was confirmed that two degradation pathways were involved during hydrolysis of cefdinir to the lactone.

Administration, Oral↗
PubMed1996

[Chest wall reconstruction after the resection of primary chest wall tumors].

Between April 1983 and June 1994, we performed chest wall reconstructions on 9 patients (7 males and 2 females) out of 27 all of whom underwent the radical resection for the primary chest wall tumors. Histological diagnosis of tumors included 6 chondrosarcomas, 1 Ewing's sarcoma, 1 plasmacytoma and 1 giant cell tumor. Six lesions were located on the rib and 3 on the sternum. For the materials for reconstruction of the chest wall use a polyethylene plate in 2 patients, a Marlex mesh in 5 patients and a Marlex mesh with a methyl methacrylate utilizing the sandwich method in 2 patients. The polyethylene plate proved to be satisfactory for maintaining stability of the chest wall. However, our experience using this plate showed intensive foreign body reactions, and discovering these we have not use the polyethylene plate. Marlex mesh had an affinity with human tissue and was very easy to use and produced no complications. We use Marlex mesh for flat surfaces on the anterior or posterior chest wall. Marlex mesh and methyl methacrylate utilizing the sandwich method, combined the solidity and shaping of methyl methacrylate with the benefit such as easy fixation and excellent incorporation of the mesh.

Adult↗
PubMed1995

[Two cases of empyema treated with rectus abdominis myocutaneous flap and muscle flap].

A rectus abdominis myocutaneous flap (RAM flap) has often been useful in breast reconstructions after the surgical therapy for breast cancer, or in other plastic surgeries. However, there have been few reports concerning about its applications for intrathoracic diseases. In this paper, we report two cases of recurrent empyema treated with RAM flap and muscle flap from rectus abdominis. One case is 75-year-old male with right-empyema and bronchial fistula after the thoracoplasty due to lung tuberculosis. The bronchial fistula was successfully closed with muscle flap from the right rectus abdominis. The other is 33-year-old male with left empyema and cutaneous fistula after the hemothorax due to traffic accident. He contracted with MRSA in his thoracic cavity. We resected the fistula and reconstructed his left chest wall with left RAM flap. The muscle flap from rectus abdominis or RAM flap has been very effective for the therapy of bronchial fistula after lung tuberculosis, and for the reconstruction of chest wall.

Adult↗
PubMed1994

[Clinical experience with the CHAUX multi-purpose retractor].

We have performed dissection of the ITA using the CHAUX retractor in many patients. This retractor is a two-point sternal/IMA and valve retractor, with four sternal blades with individual and independent dual movement. The sliding sternal blade assemblies permit movement along the horizontal plane of the side arm. This retractor can be used for other types of cardiac surgery, as well. We obtained good results with its use for repair of distal aortic arch aneurysm. We conclude that this retractor is safe and useful for cardiac surgery.

Humans↗
PubMed1993

Tautomeric phenomenon of a novel potent immunosuppressant (FK506) in solution. I. Isolation and structure determination of tautomeric compounds.

Tautomeric phenomenon was observed in the HPLC chromatogram obtained from a novel potent immunosuppressant, FK506, in ethanol solution. Two tautomeric compounds derived from FK506 were isolated and purified by HPLC. Their structures were elucidated by spectral analyses. The mechanisms for this tautomerization were also established based on the results of structure analysis.

Isomerism↗
PubMed1992

Quantitative mapping of the N-linked sialyloligosaccharides of recombinant erythropoietin: combination of direct high-performance anion-exchange chromatography and 2-aminopyridine derivatization.

A rapid quantitative analysis of the sialylated N-linked oligosaccharides of recombinant erythropoietin (EPO) expressed in Chinese hamster ovary (CHO) cells has been developed. The procedure utilizes a glycoamidase (glycopeptidase F) to release all of the N-linked oligosaccharides from the native glycoprotein, followed by direct chromatographic analysis using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection. The eight sialyloligosaccharides isolated from HPAEC were characterized by derivatizing with 2-aminopyridine followed by two-dimensional HPLC mapping of the pyridylaminated asialooligosaccharides (Tomiya et al., 1988, Anal. Biochem. 171, 73-90). Seven kinds of complex-type asialooligosaccharides were identified ranging from a biantennary structure to N-acetyllactosamine-extended tetraantennary structure. Approximately 3% of the terminal galactose residues of the oligosaccharides released from EPO were not sialylated whereas 97% contained an alpha(2-->3)-linked sialic acid. Quantitative oligosaccharide mapping of four different lots of EPO from CHO cells was performed to quantify the molar balance and distribution of the N-linked oligosaccharides. The sialyloligosaccharides were distributed with approximately 5% disialylated (single type), 20% trisialylated (six types), and 75% tetrasialylated (four types) oligosaccharides with an average molar recovery of 85% starting from 750 pmol of EPO.

Amidohydrolases↗
PubMed1992

De novo glucan synthesis by mutants streptococcal glucosyltransferases present in pellicle promotes firm binding of Streptococcus gordonii to tooth surfaces.

Adherence of 3H-labelled cells of Streptococcus gordonii and Streptococcus milleri to artificial pellicles prepared from saliva supplemented with glucosyltransferases from mutants streptococci was examined using a new assay for sucrose-dependent cell-to-pellicle attachment. Results indicate that S. gordonii, but not S. milleri, could attach tightly to hydroxylapatite surfaces through de novo glucan synthesis by mutants streptococcal glucosyltransferases present in the experimental salivary pellicles.

Bacterial Adhesion↗
PubMed1992

The directions of static skin tensions in the face: their roles in facial incisions.

The circular excisions of facial skin lesions were performed in 202 sites on 126 patients. The shapes of the resultant defects were observed to identify the directions of skin tensions in a static state. The round shapes remained in the forehead, temple, and nose. In the other areas of the face, the wounds were stretched in certain directions and became elliptical. The orientations of the facial static tensions were identical to the wrinkle lines in many facial areas. It is suggested that the wrinkle lines show the optimal directions of selective incisions in most facial areas except for the medial canthus and upper and lower lips.

Adolescent↗