Biomedical subjects

Keigyou Yoh

Publications and source records attributed to Keigyou Yoh.

22 records · Page 2Linked to original sources

PubMed2003

Electron paramagnetic resonance imaging of nitric oxide organ distribution in lipopolysuccaride treated mice.

The recent development of electron paramagnetic resonance (EPR) permits its application for in vivo studies of nitric oxide (NO). In this study, we tried to obtain 3D EPR images of endogenous NO in the abdominal organs of lipopolysuccaride (LPS) treated mice. Male ICR mice, each weighing about 30 g, received 10 mg/kg of LPS intraperitoneally. Six hours later, a spin trapping reagent comprised of iron and an N-dithiocarboxy sarcosine complex (Fe(DTCS)2, Fe 200 mM, DTCS/Fe = 3) were injected subcutaneously. Two hours after this treatment, the mice were fixed in a plastic holder and set in the EPR system, equipped with a loop-gap resonator and a 1 GHz microwave. NO was detected as an NO-Fe(DTCS)2 complex, which had a characteristic 3-line EPR spectrum. NO-Fe(DTCS)2 complexes in organ homogenates were also measured using a conventional X-band EPR system. NO-Fe(DTCS)2 spectra were obtained in the upper abdominal area of LPS treated mice at 8 h after the LPS injection. 3D EPR tiled and stereoscopic images of the NO distribution in the hepatic and renal areas were obtained at the same time. The NO-Fe(DTCS)2 distribution in abdominal organs was confirmed in each organ homogenate using conventional X-band EPR. This is the first known EPR image of NO in live mice kidneys.

Animals↗

PubMed2002

Reduced serum hydroxyl radical scavenging activity in erythropoietin therapy resistant renal anemia.

Relation between anemia resistant to recombinant human erythropoietin (rHuEPO) therapy and the oxidative stress in hemodialysis (HD) patients was investigated. Stable HD patients who had consistent hemoglobin concentrations on a constant dose of rHuEPO were studied. Patients were excluded if there were factors that might affect hemopoiesis or administration of antioxidant supplements. Patients were classified into three groups: High (9000 U/week), Low (1500-4500 U/week) and No rHuEPO group. Thiobarbituric acid reactive substances (TBARS) of sera and erythrocyte were examined. Serum superoxide and hydroxyl radical scavenging activities were measured using electron spin resonance. TBARS in the erythrocyte was higher in High rHuEPO group compared with No rHuEPO group, though the serum TBARS were similar. A diminution of serum hydroxyl radical scavenging activity was observed in High rHuEPO group. Hydroxyl radical signal intensity showed a strong correlation with the serum ferritin in High rHuEPO group, although ferritin concentrations were not different among the 3 groups. Superoxide scavenging activity showed no differences. These results indicate that increased lipid peroxidation in erythrocyte, raised by decreased serum hydroxyl radical scavenging activity, is one cause of rHuEPO resistant anemia. Serum ferritin may be involved in this hydroxyl radical production.

Aged↗

PubMedDate not supplied

Staphylococcal cell membrane antigen, a possible antigen in post-methicillin resistant Staphylococcus aureus (MRSA) infection nephritis and IgA nephropathy, exhibits high immunogenic activity that is enhanced by superantigen.

BACKGROUND: The post-methicillin resistant Staphlylococcus aureus (MRSA) infection nephritis is a progressive glomerulonephritis that occurs following Staphylococcus aureus infection. It has been assumed that staphylococcal superantigens and other cellular antigens are necessary for the development of post-MRSA infection nephritis, and we have previously identified a staphylococcal cell membrane antigen (GenBank, accession number; BAB41819.1) as a possible antigen in post-MRSA infection nephritis. In this study, we assessed the immunogenic activity of the staphylococcal cell membrane antigen and determined the relationship between the cell membrane antigen and superantigen. METHODS: Balb/c mice were immunized with glutathione S-transferase (GST) or staphylococcal cell membrane antigen-GST fusion protein. One week later, their lymphocytes were cultured with or without toxic shock syndrome toxic-1 (TSST-1) for one week. Immunoglobulin levels in the culture supernatants were measured by ELISA, and transcript expressions for cytokines, and the T-cell receptors (TCR) Vbeta17 (activated by TSST-1), Vbeta1 and Vbeta8 (not activated by TSST-1) in the culture were analyzed by reverse transcriptase polymerase chain reaction. RESULTS: Neither IgG nor IgA were detected in the culture supernatant of GST-primed lymphocytes, with or without TSST-1. In contrast, IgG and IgA levels gradually increased in direct proportion to the TSST-1 concentration in the supernatants of staphylococcal cell membrane antigen-GST fusion protein-primed lymphocytes. Various cytokine messenger RNA (mRNA) transcripts were detected in both GST-primed and staphylococcal cell membrane antigen-GST-primed cells in the presence of TSST-1. A Vbeta17 transcript could not be detected during the early culture phase under both culture conditions, while Vbeta1 and Vbeta8 T-cells survived for 7 days in the staphylococcal cell membrane antigen-GST fusion protein-primed culture in the presence of TSST-1. CONCLUSION: These results suggest that staphylococcal cell membrane antigen-GST-primed T-cells were stimulated more than GST-primed cells. Their activity was enhanced further in the presence of cytokines, which were induced by TSST-1, such that the T-cells were able to survive and activate B-cells to produce immunoglobulins.

Animals↗

PubMedDate not supplied

Post-MRSA infection glomerulonephritis with marked Staphylococcus aureus cell envelope antigen deposition in glomeruli.

A 48-year-old male developed massive proteinuria and renal dysfunction after pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) infection. Examination of a renal biopsy specimen by light microscopy showed severe mesangiocapillary proliferative glomerulonephritis with fibrocellular crescents. Immunofluorescence microscopy showed weak linear staining for immunoglobulin G (IgG), while both the peripheral and mesangial lesions stained for IgA and C3. Immunostaining for a possible antigen related to post-MRSA infection glomerulonephritis, using monoclonal antibody S1D6, revealed marked deposition of S.aureus cell envelope antigen in the glomeruli. Electron-dense deposits were observed in both the subendothelial and the mesangial areas. Focal subendothelial widening accompanied with monocytes or foam cell infiltration was also seen. The findings reflect a typical post-MRSA infection glomerulonephritis caused by S.aureus cell envelope antigen.

Antigens, Bacterial↗