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Biomedical subjects

F Saitoh

Publications and source records attributed to F Saitoh.

At least 19 recordsLinked to original sources
PubMed2001

Inhibitory effect of M50054, a novel inhibitor of apoptosis, on anti-Fas-antibody-induced hepatitis and chemotherapy-induced alopecia.

M50054, 2,2'-methylenebis (1,3-cyclohexanedione), was identified as a novel inhibitor of apoptosis (programmed cell death) using an in vitro cell death assay system induced in human Fas-expressing WC8 cells by soluble human Fas ligand. Furthermore, M50054 inhibited the apoptotic cell death of U937, a human monocytic leukemic cell line, induced by anticancer agents such as etoposide; it was also confirmed that M50054 inhibited apoptotic features such as DNA fragmentation and phosphatidylserine exposure in these cells. These anti-apoptotic effects were attributable to inhibition of caspase-3 activation. Additionally, M50054 significantly inhibited anti-Fas-antibody-induced elevation of plasma alanine aminotransferase and aspartate aminotransferase. Alopecia (hair loss) symptoms were also significantly improved with topical treatment with M50054. In conclusion, M50054 inhibits apoptosis induced by a variety of stimuli via inhibition of caspase-3 activation, and may thus be effective for hepatitis and chemotherapy-induced alopecia.

Alopecia↗
PubMed2001

Biochemical evidence for localization of AMPA-type glutamate receptor subunits in the dendritic raft.

A low density Triton-insoluble fraction with characteristic lipid composition was prepared from synaptic plasma membrane from the rat forebrain. The fraction was named dendritic raft based on its absence of the presynaptic marker synaptophysin, the presence of postsynaptic Glutamate receptor (GluR) subunits, and its resemblance to raft, caveolae-like structure. We found a differential distribution of NMDA-type and AMPA-type GluR subunits in the dendritic raft and postsynaptic density (PSD) fractions; the latter type GluR subunits were localized to the dendritic raft as well as PSD fraction, whereas the former type was mostly localized to the PSD fraction. We also found the differential distribution of the components of ras/mitogen-activated protein kinase (MAPK) pathway to the dendritic raft and PSD fractions. Dendritic raft and PSD may possibly interact at the postsynaptic sites for efficient signal processing that is required for expression of synaptic plasticity.

Animals↗
PubMed2001

Primary retroperitoneal ganglioneuroblastoma in an adult.

A case of retroperitoneal ganglioneuroblastoma in a 60-year-old man is reported. This retroperitoneal tumor was surgically removed and pathologic diagnosis was ganglioneuroblastoma. Ganglioneuroblastoma usually occurs in children and is extremely rare in adults. The characteristics are described of an unusual tumor based on the published reports.

Ganglioneuroblastoma↗
PubMed1999

A 22-year course of the Kay-Shiley disc valve with muscle guard at the mitral position.

Almost 33 years have elapsed since the introduction of the Kay-Shiley disc valve in Japan. Following the development of pyrolite carbon, the Kay-Shiley valve is no longer in clinical use. We report the case of a female patient who had had an isolated mitral valve replacement with the Kay-Shiley disc valve with single muscle guard 22 years previously. After numerous thromboembolic episodes with the Kay-Shiley disc valve, a successful reoperation was done with the CarboMedics valve. The explanted valve revealed that the grooved occluder disc had a loosely adherent clot. The thromboembolism is a notorious complication associated with this valve. We recommend re-replacement of the Kay-Shiley valve whenever possible.

Adult↗
PubMed1999

Arginine-55 in the beta-arm is essential for the activity of DNA-binding protein HU from Bacillus stearothermophilus.

DNA-binding protein HU (BstHU) from Bacillus stearothermophilus is a homodimeric protein which binds to DNA in a sequence-nonspecific manner. In order to identify the Arg residues essential for DNA binding, four Arg residues (Arg-53, Arg-55, Arg-58, and Arg-61) within the beta-arm structure were replaced either by Gln, Lys, or Glu residues, and the resulting mutants were characterized with respect to their DNA-binding activity by a filter-binding analysis and surface plasmon resonance analysis. The results indicate that three Arg residues (Arg-55, Arg-58, and Arg-61) play a crucial role in DNA binding as positively charged recognition groups in the order of Arg-55 > Arg-58 > Arg-61 and that these are required to decrease the dissociation rate constant for BstHU-DNA interaction. In contrast, the Arg-53 residue was found to make no contribution to the binding activity of BstHU.

Arginine↗
PubMed1999

Pulse intravenous cyclophosphamide treatment for steroid-resistant interstitial pneumonitis associated with polymyositis.

Interstitial pneumonitis (IP) is a serious complication in polymyositis/dermatomyositis (PM/DM), leading to significant morbidity or mortality. Here, we report the successful treatment by pulse intravenous administration of cyclophosphamide in the early course of lung involvement in PM, and with subsequent low-dosage oral administration of azathioprine in a patient with steroid-resistant IP associated with PM/DM. Although the precise pharmacological mechanism induced by cyclophosphamide in this disease remains unclear, such a cytotoxic drug raises the possibility of control of steroid-resistant PM/DM-associated IP when used in the early course of IP.

Adult↗
PubMed1999

[Necessity and usefulness of detection by PCR of mecA and aac(6')/aph(2") genes for identification of arbekacin-resistant MRSA].

Arbekacin (ABK)-resistant bacteria (43 strains) isolated as MRSA by regular clinical procedures in Japanese clinics in 1998 were characterized in terms of taxonomic properties, aminoglycoside resistance, and mecA and aac(6')/aph(2") genes linking with ABK-resistant MRSA. Taxonomically the 43 strains fell into Staphylococcus aureus (33 strains) and Enterococcus (10 strains). As to ABK resistance, the 13 strains of MRSA clinically reported as high ABK resistance (128 micrograms/ml or higher) did not show clear high ABK resistance except for 2 strains when their ABK resistance was tested using 0.5% NaCl containing nutrient agar. We designed and established the primers and conditions for PCR to detect the above two resistance genes. PCR analysis of DNAs from the 43 strains clearly indicated that only 33 strains identified taxonomically as S. aureus possessed mecA indicating MRSA and 23 out of them possessed aac(6')/aph(2"). The other 10 strains of MRSA lacking aac(6')/aph(2") were ABK-sensitive. Thus, there were a good correlation between ABK resistance and aac(6')/aph(2") existence. Based on these, it was conclusive that the appropriate ABK resistance test as well as the detection of mecA and aac(6')/aph(2") genes by PCR are necessary and useful to avoid false ABK-resistant MRSA strains.

Acetyltransferases↗
PubMed1999

Assessment of coronary artery bypass surgery by exercise thallium imaging.

The purpose of this study was to assess the coronary artery bypass grafting (CABG) in exercise thallium-201 scintigraphy. The study was performed on 18 consecutive patients undergoing elective surgery. We compared the results of the scintigraphic examinations, 1 week before and 1 month postoperatively. Of the 47 bypass grafts, 20 (42. 6%) grafts contributed to the improvement of the ischemic areas and 38% of the bypass grafts did not change the scintigraphic patterns after surgery. Some bypass grafts had been performed on the stenotic arteries that dominated the areas which preoperatively showed normal exercise scintigraphic patterns yet were considered to worsen in the near future. Such grafts main contribution may be to protect and to increase the overall myocardial washout ratio for prevention of an enlargement of ischemic areas.

Aged↗
PubMed1998

Management of recurrent pilocytic astrocytoma with leptomeningeal dissemination in childhood.

Two cases of recurrent pilocytic astrocytoma with leptomeningeal dissemination (LMD) are described. A 6-year-old boy presented with a cerebellar tumor, which was subtotally removed. Tumor recurrence with LMD occurred 4 years later. Reoperation for tumor removal followed by craniospinal irradiation stabilized the LMD over 5 years. A 4-year-old girl presented with a chiasmatic-hypothalamic tumor. Partial removal of the tumor was followed by radiation therapy. Tumor regrowth with LMD occurred 4 years later and was managed by reoperation, chemotherapy and radiotherapy. Tumor recurrence with LMD can be stabilized by multimodal treatment without tumor progression.

Arachnoid↗
PubMed1997

Characterization of beta-1,2-mannosyltransferase in Candida guilliermondii and its utilization in the synthesis of novel oligosaccharides.

A particulate insoluble enzyme fraction containing mannosyltransferases from Candida guilliermondii IFO 10279 strain cells was obtained as the residue after extracting a 105,000 x g pellet of cell homogenate with 1% Triton X-100. Incubation of this fraction with a mannopentaose, Manalpha1-->3(Manalpha1-->6)Manalpha1-->2Manalpha1+ ++-->2Man, in the presence of GDP-mannose and Mn2+ ion at pH 6.0 gave a third type of beta-1,2 linkage-containing mannohexaose, Manbeta1-->2Manalpha1-->3(Manalpha1-->6)Manalpha1++ +-->2Manalpha1-->2Man , the structure of which was identified by means of a sequential NMR assignment. The results of a substrate specificity study indicated that the beta-1,2-mannosyltransferase requires a mannobiosyl unit, Manalpha1--> 3Manalpha1-->, at the nonreducing terminal site. We synthesized novel oligosaccharides using substrates possessing a nonreducing terminal alpha-1,3-linked mannose unit prepared from various yeast mannans. Further incubation of the enzymatically synthesized oligosaccharide with the enzyme fraction gave the following structure, Manbeta1-->2Manbeta1-->2Manalpha1-->3(Manalpha1- ->6)Manalpha1--> 2Manalpha1-->2Man, which has been found to correspond to antigenic factor 9. Incubation of Candida albicans serotype B mannan with the enzyme fraction gave significantly transformed mannan, which contains the third type of beta-1,2-linked mannose units.

Antigens, Fungal↗
PubMed1997

[Variations in mesenchymal cell activity between rheumatic and non-rheumatic valve disease].

Deoxyribonucleic acid (DNA) synthesis of mesenchymal cells in the diseased valve tissue of patients with rheumatic and non-rheumatic valve diseases were compared. Surgically resected mitral valves from eight rheumatic and eight non-rheumatic patients in their 40s were examined immunohistochemically to estimate the activity of the various mesenchymal cells by cell cycle analysis, using monoclonal antibodies to cyclin E, A, B1, p53, and b cl-2 after routine tissue fixation, paraffin embedding and sectioning. Cyclin B1-positive fibrocytes and fibroblasts of the spongiosa and fibrosa were observed in all non-rheumatic cases, whereas some lymphocytes in the perivascular area were cyclin B1-, p53- and b cl-2-positive in rheumatic cases. The distinct qualitative difference in the mesenchymal cells of valve tissue between rheumatic and non-rheumatic etiologies suggests a different mode of valve pathology.

Adult↗
PubMed1997

[Concealed infective endocarditis].

The occurrence of concealed infection or "natural remission" in infective endocarditis was investigated microscopically in 35 consecutive patients (36 valves) with infective endocarditis (between April 1987 and May 1995). Four patients were considered as having concealed or silent infective endocarditis. Preoperative diagnosis of these patients was mitral valve prolapse, rheumatic aortic valve stenosis with insufficiency, aortic valve prolapse and hypertrophic cardiomyopathy, respectively. These patients did not present with any clinical signs of infective endocarditis such as cardiac murmur and ventricular dysfunction. Histological examination of the excised valves revealed valvular perforation, small round cell infiltration, neovascularization, remnants of vascular smooth muscle cells, and organizing vegetations. These findings are consistent with the histological findings of infective endocarditis. Latent infective endocarditis may be present without inflammatory manifestation.

Aortic Valve Insufficiency↗
PubMed1996

Characterization of alpha-1,6-mannosyltransferase responsible for the synthesis of branched side chains in Candida albicans mannan.

A particulate insoluble fraction from Candida albicans NIH B-792 (serotype B) strain cells was obtained as the residue after extracting a 105000 x g pellet of cell homogenate with 1% Triton X-100. Incubation of this fraction with a mannopentaose, Man alpha 1-->3Man alpha 1-->2Man alpha 1-->Man alpha 1-->2Man, in the presence of GDP-mannose and Mn2+ at pH 6.0 gave a branched mannohexaose, [sequence: see text] 6 the structure of which was identified by means of sequential off assignment. However, the enzyme fraction obtained from Candida parapsilosis gave Man alpha 1-->2Man alpha 1-->3Man alpha 1-->2Man alpha 1-->2 Man alpha 1-->2Man under the same conditions. These results demonstrate the finding that the structural difference in the mannans of these two species is due to the presence of alpha-1.6-linked branching mannose units in the C. albicans mannan [Shibata, N., Ikuta, K., Imai, T., Satoh, Y., Satoh, R., Suzuki, A., Kojima, C., Kobayashi, H., Hisamichi, K. & Suzuki, S. (1995) J. Biol. Chem. 270, 1113-1122]. The substrate-specificity study of the enzyme indicated that the structural requirement of the alpha-1,6-mannosyltransferase is Man alpha 1-->3Man alpha 1-->. The alpha-1,6-mannosyltransferase also transferred the alpha-1,6-linked branching mannose unit to the mannan of Saccharomyces cerevisiae. The transformation of the mannan was detected by the appearance of antigenic factor 4 using an enzyme-linked immunosorbent assay and two-dimensional homonuclear Hartmann-Hahn spectroscopy.

Candida↗
PubMed1996

[Surgical pathology of infective endocarditis].

Underlying pathologic disorders of infected valves were analyzed in 36 consecutive patients with infective endocarditis (from April 1987 to May 1995) of 18 aortic, 11 mitral and 8 prosthetic valves. Among 29 cases of native valve endocarditis, 27 had known organic changes [aortic valve prolapse 8, bicuspid aortic valve 4, annuloaortic ectasia 1, mitral valve prolapse 9 (including 2 cases associated with hypertrophic cardiomyopathy), looping chordae 1, rheumatic heart disease 4]. However, the remaining two cases had unknown etiology. Histological examination of these two aortic valves revealed proliferation of small vessels and remnants of vascular smooth muscle cells, suggesting postinflammatory valve prolapse. Five cases with definite pathology had no clinical signs of infection. The preponderance of surgically resected valves with infective endocarditis in Japan is non-rheumatic in origin.

Adult↗
PubMed1994

[A case of quadricuspid aortic valve associated with mitral insufficiency].

We report a case of a 70-year-old woman who had congenital quadricuspid aortic valve. She had undergone Manouguian's operation because of the narrow annulus associated with aortic steno-insufficiency and mitral insufficiency. The aortic valve was found to have 4 equal-sized cusps. The noncoronary cusp was divided into two equal parts. This congenital quadricuspid valve was extremely rare anomaly and we have nerve seen the case which had been corrected surgically by Manouguian's procedure. The aortic valve was replaced by a 23 mm St. Jude Medical prosthesis and the mitral valve was replaced by a 29 mm CarboMedics prosthesis. The postoperative course was uneventful and she is doing well six months after operation.

Aged↗
PubMed1994

[Successful treatment by Konno's operation for congenital aortic stenosis associated with hypoplastic valve ring].

A 47-year-old woman with congenital aortic stenosis associated with hypoplastic aortic valve ring underwent aortic valve replacement by Konno method. We have to be careful preventing residual VSD because the left ventricular muscle was weak in the aged with congenital aortic stenosis. In early postoperative period, we also have to do a careful treatment in case by Konno's operation, particularly in the patient of advanced age. However, she made a satisfactory recovery with adequate size of aortic valve replacement.

Aortic Valve↗
PubMed1994

[Autologous fibrin glue from concentrated platelet rich plasma: intraoperative plasma sequestration using autotransfusion device].

Making autologous fibrin glue from intraoperatively collected concentrated platelet rich plasma (C-PRP) was attempted in 5 patients who underwent elective coronary artery bypass. The autologous blood was withdrawn from the patient before cardiopulmonary bypass and sequestrated for C-PRP, concentrated red cells (CRC) and platelet poor plasma (PPP) using an Electromedics Elmd-500 autotransfusion device. CRC and PPP were returned intravenously to the patient as needed intraoperatively or postoperatively. Aprotinin was dissolved in C-PRP to yield a concentration of 1000U/ml to the aim of suppressing the plasmin activity. In another syringe, thrombin was dissolved in 2% calcium chloride solution to 1000U/ml. The C-PRP/aprotinin was mixed in ratios of 20:1, 10:1, 5:1, 3:1 to the thrombin/C a++ solution and observed the time for clotting. The 10:1 and 5:1 mixture usually clotted within 3-5 seconds, whereas it was necessary 5 or more seconds in other ratios. Therefore we used in the ratio of 5:1 for all patients. The fibrin glue from this technique is little different from the fibrin glue on the market in its viscosity, and has some major advantages 1. large amount of glue is available 2. simple and inexpensive 3. eliminate the risk of side effect such as virus transmission.

Blood Platelets↗