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Biomedical subjects

Yuji Sato

Publications and source records attributed to Yuji Sato.

At least 55 records · Page 3Linked to original sources
PubMed2004

Identification of epidermal growth factor receptor-derived peptides recognised by both cellular and humoral immune responses in HLA-A24+ non-small cell lung cancer patients.

The epidermal growth factor receptor (EGFR) is one of the most appropriate target molecules for cancer therapy because of its high expression in epithelial cancers. A novel EGFR-tyrosine-kinase inhibitor, ZD1839, has been approved as a drug for non-small cell lung cancer (NSCLC), and many other agents are now being tested in clinical trials. Cytotoxic T lymphocyte (CTL)-directed epitope peptides could be another class of useful compounds in EGFR-targeted therapies. However, at present, there are no data on CTL-directed peptides of EGFR. Therefore, this study aimed to identify immunogenic EGFR-derived peptides in HLA-A24(+) NSCLC patients. We report in this study three such EGFR-derived peptides at positions 54-62, 124-132 and 800-809. These peptides were recognised by both cellular and humoral immune responses in most of the peripheral blood mononuclear cells (PBMCs) and sera from NSCLC patients that we tested. These results may provide a scientific basis for the development of EGFR-based immunotherapy.

Antibody Formation↗
PubMed2004

Synaptic scaffolding molecule is involved in the synaptic clustering of neuroligin.

S-SCAM has a similar molecular organization to PSD-95. Both of them interact with a cell adhesion molecule, neuroligin. We previously reported that beta-catenin binds S-SCAM and recruits it to synapses. We have here examined using rat primary cultured neurons whether neuroligin recruits S-SCAM to synapses or S-SCAM determines the localization of neuroligin. Overexpressed neuroligin formed larger clusters under co-expression of S-SCAM but not of PSD-95. Overexpressed neuroligin blocked synaptic accumulation of PSD-95 but not of S-SCAM. S-SCAM mutant containing the neuroligin-binding region interfered with synaptic accumulation of neuroligin and PSD-95, whereas the similar mutant of PSD-95 had no effect. Biochemical studies revealed that neuroligin forms a ternary complex with S-SCAM and PSD-95 through manifold interactions. These findings imply that S-SCAM is tethered by beta-catenin to synapses and induces synaptic accumulation of neuroligin, which subsequently recruits PSD-95 to synapses.

Adaptor Proteins, Signal Transducing↗
PubMed2004

The feeding of beta-carotene down-regulates serum IgE levels and inhibits the type I allergic response in mice.

Feed containing beta-carotene was administered orally to BALB/c mice immunized intraperitoneally with ovalbumin (OVA) for approximately 1 month. The titers of OVA-specific IgE, OVA-specific IgG1 and OVA-specific IgG2a in the mouse sera were determined. The OVA-specific IgE titer and OVA-specific IgG1 titer by mice fed beta-carotene were significantly inhibited. On the other hand, the OVA-specific IgG2a titer in mice fed beta-carotene was significantly greater than those of control mice. The OVA-specific IgE suppression of beta-carotene feeding was dose-dependent. We also examined the effect of fed beta-carotene on active systemic anaphylaxis. Feeding beta-carotene to mice immunized with OVA inhibited the immediate reduction of the body temperature induced by antigen stimulation. Furthermore, the increase in serum histamine in the mice fed beta-carotene under active systemic anaphylaxis was lower than in controls. We then examined the pattern of cytokine production by spleen cells from mice followed by restimulation with OVA in vitro. The spleen cells from the mice fed beta-carotene produced more IFN-gamma, IL-12 and IL-2 than those from the control group. In contrast, the spleen cells from the mice fed beta-carotene produced less IL-4, IL-5, IL-6, IL-10 than those from the control group. Furthermore, analysis of IFN-gamma mRNA levels of the splenocytes using the real-time quantitative RT-PCR technique revealed higher levels in the splenocytes from the mice fed beta-carotene. These findings suggest that feeding beta-carotene improves the helper T cell (T(H))1-T(H)2 balance, inhibiting specific IgE and IgG1 production and antigen-induced anaphylactic response.

Animals↗
PubMed2004

Relationship between serum IgA/C3 ratio and progression of IgA nephropathy.

OBJECTIVE: The serum IgA/C3 ratio might be considered to serve as a diagnostic marker for patients with IgA nephropathy (IgAN), but its value as a marker of the severity of histological lesions or prognosis is unknown. METHODS: We studied the serum IgA/C3 ratio, using standardized reference material, in 86 patients with IgAN and in 32 with non-IgAN. The patients with IgAN were divided according to the severity of histological lesions (mild IgAN, n=29 and severe IgAN, n=57) based on Japanese clinical guidelines. RESULTS: The serum IgA level was significantly higher, while its C3 level was lower in patients with severe IgAN compared to those with non-IgAN. However, these levels were not different between patients with mild IgAN and non-IgAN. In contrast, the serum IgA/C3 ratio obviously differed among the three groups (2.47+/-0.96 vs. 3.63+/-1.44 vs. 4.72+/-1.86; p<0.01, ANOVA). Kaplan-Meier analysis of the patients with IgAN classified according to the mean serum IgA/C3 ratio revealed that the group with high serum IgA/C3 (4.5 and above) had a significantly poorer renal outcome (p<0.05, log-rank test), since the cumulative renal survival rate at 5 years was 84.4% vs. 100%. The ratio (%) of patients with severe IgAN in whom hematuria disappeared, was significantly higher in the low, than in the high serum IgA/C3 group (41.9% vs. 15.4%; p<0.05, t-test). CONCLUSION: The serum IgA/C3 ratio appears to reflect the histological severity of IgAN and could serve as a marker of the progression of IgAN.

Adult↗
PubMed2004

Nephrotic syndrome caused by membranous nephropathy: response to a short course of cyclophosphamide alternating with prednisolone.

OBJECTIVE: The optimal duration of immunosuppressive therapy and the timing of treatment for treating membranous nephropathy (MN) have yet to be established. We examined outcomes of a short course of cyclophosphamide alternating with prednisolone for MN patients with nephrotic syndrome. METHODS AND PATIENTS: Cyclophosphamide (2 mg/kg/day for 8 weeks) combined with prednisolone (1 mg/kg every 48 hours for 8 weeks, then tapering off for 1 year) was prescribed for 28 MN patients (12 men and 16 women; mean age 52.4+/-2.25 years SEM). We first evaluated the response rates to this combined therapy, then compared the clinical characteristics of those who achieved remission (group A) with those who did not (group B) within 6 months of the start of treatment. RESULTS: The incidences of complete and partial remission increased with the follow-up period; 32 and 21% by 6 months, 54 and 29% by 12 months, and 79 and 11% by 24 months, respectively. Serum IgG (906+/-100.8 versus 562+/-66.1 mg/day; p<0.01) was significantly higher in group A, and the selectivity index (C(IgG)/C(albumin) 0.16+/-0.015 versus 0.30+/-0.040; p<0.01), significantly lower. Nephrotic syndrome persisted in 3 group B patients (23%), who finally had impaired renal function. CONCLUSION: MN patients with nephrotic syndrome responded favorably to a short course of cyclophosphamide combined with prednisolone. The serum IgG level and selectivity index may serve as markers of early response to this treatment.

Biopsy, Needle↗
PubMed2004

Minimal change nephrotic syndrome after allogenic hematopoietic stem cell transplantation.

We describe a 24-year-old man who developed minimal change nephrotic syndrome after allogenic hematopoietic stem cell transplantation (HSCT). One year after undergoing allogenic peripheral blood stem cell transplantation (PBSCT), this patient presented with proteinuria. He also presented with skin and lip lesions considered to be chronic graft-versus host disease. Observation of renal biopsy specimens by light microscopy revealed minor glomerular abnormalities. However, electron microscopy disclosed focal mesangial interposition, irregular thickening of the glomerular basement membrane and subendothelial loosening. Two years after HSCT, the patient developed nephrotic syndrome. Long use of cyclosporine improved the proteinuria and hypoalbuminemia within 12 months.

Adult↗
PubMed2004

[Neoadjuvant chemoradiotherapy for advanced squamous cell carcinoma of thoracic esophagus].

Advanced thoracic esophageal cancer has a poor prognosis despite advances in surgery, such as three-field lymph node dissection. Multimodal therapy is needed to improve local control, resectability and survival rate. Fifteen patients with advanced squamous cell carcinoma of the thoracic esophagus were treated with neoadjuvant chemoradiotherapy (NAC) combined with concurrent radiation (30 Gy/12 f) and 3 courses of 5-FU and CDDP (CDDP 5 mg/m2/day + 5-FU 250 mg/m2/day: day 1-5: div). In the absence of unresectable disease and surgical risk, 12 patients underwent esophagectomy (Group 1) and 3 patients underwent additional chemoradiotherapy because of high surgical risk (Group 2). Side effects consisted of nausea, vomiting and myelo-suppression in 8 patients, but all patients tolerated and completed a full course of NAC. The effective rate (CR + PR) of NAC was 58.3% in Group 1 and 66.7% in Group 2. No patients showed pathological CR. Two-year survival rate was 28.1% in Group 1 (PR: 33.3%, NC: 20.0%) and 33.5% in Group 2. This protocol had acceptable toxicities but did not show survival benefit. Further trials are necessary to improve survival rate.

Aged↗
PubMed2004

Immunological evaluation of vaccination with pre-designated peptides frequently selected as vaccine candidates in an individualized peptide vaccination regimen.

We previously conducted a trial of an 'individualized' regimen, in which cancer patients were vaccinated with peptides after the confirmation of pre-existing peptide-specific cytotoxic T lymphocyte (CTL) precursors. In this study, we performed a new trial of 'pre-designated' regimen, in which cancer patients were vaccinated with peptides that were frequently selected as vaccine candidates in the preceding individualized regimen. Eighteen cancer patients (10 with uterine cervical cancer and 8 with gastric cancer) were enrolled in the new regimen. The pre-designated regimen was well tolerated by all patients. Although peptide-specific CTL precursors and humoral responses increased in the majority of patients with the pre-designated regimen, neither of the responses correlated with clinical outcome. Three patients had long stable disease, and their pre-vaccination peripheral blood mononuclear cells contained peptide-specific CTL precursors reactive to more than 2 of 4 peptides. With the pre-designated regimen, the levels of pre-existing immunoglobulin G reactive to non-vaccinated peptides decreased in 5 of 15 patients with progressive disease, and their time to progression was very short, whereas such a decrease was rarely observed in the preceding individualized regimen. These results suggest that the pre-designated regimen can elicit a primary immune response, but may incidentally suppress pre-existing immune responses.

Adult↗
PubMed2003

Increase of human MTH1 and decrease of 8-hydroxydeoxyguanosine in leukocyte DNA by acute and chronic exercise in healthy male subjects.

To investigate the effects of exercise on oxidative DNA damage, we measured the levels of 8-hydroxydeoxyguanosine (8-OH-dG, 7,8,dihydro-8-oxo-deoxyguanosine), and mRNA of its sanitization enzyme, human MutT homologue (hMTH1), after mild acute exercise in healthy male subjects. The basal 8-OH-dG levels of physically active subjects were significantly lower than those of sedentary subjects. After mild exercise for 30min, the 8-OH-dG levels of the sedentary subjects significantly decreased. In correspondence with the change of 8-OH-dG levels, the hMTH1 mRNA levels of the physically active subjects were significantly higher than those of the sedentary subjects. The levels of hMTH1 mRNA of sedentary subjects significantly increased after mild exercise. Furthermore, there was a significant negative correlation between the levels of 8-OH-dG and hMTH1 mRNA. These results suggest that a mild exercise has a beneficial effect on the maintenance of low levels of 8-OH-dG probably by keeping the sanitization system at higher levels.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2003

Immunological evaluation of peptide vaccination for patients with gastric cancer based on pre-existing cellular response to peptide.

There is no standard treatment modality for advanced gastric cancer (GC) at the present time. To develop a new treatment modality, we investigated the immunological responses of advanced GC patients (n = 13, 9 non-scirrhous and 4 scirrhous types) vaccinated with peptides to a regimen under which pre-vaccination peripheral blood mononuclear cells (PBMCs) were screened for their reactivity in vitro to each of 14 peptides on HLA-A24 or 16 peptides on -A2 allele, then only the reactive peptides (maximum: 4) were administered in vivo. This regimen was generally well tolerated, although grade I levels of fever and local skin reactions were observed in several patients. Delayed-type hypersensitivity (DTH) to the vaccinated peptides was observed in 4 patients. Increased cellular and humoral immune responses to the vaccinated peptides were observed in post-vaccination PBMCs from 4 of 8 patients and in post-vaccination sera of 8 of 10 patients tested, respectively. Prolonged survival was observed in patients showing cellular and humoral immune responses to the vaccinated peptides in the post-vaccination samples, including all 4 patients with the scirrhous type. These results encourage further development of peptide-based immunotherapy for GC patients.

Adenocarcinoma↗
PubMed2003

Macrophage migration inhibitory factor (MIF): Its potential role in tumor growth and tumor-associated angiogenesis.

Macrophage migration inhibitory factor (MIF) functions as a pluripotent cytokine involved in broad-spectrum pathophysiological events in association with inflammation and immune responses. Several reports, including ours, have suggested that MIF is also involved in tumorigenesis; however, its precise role has not been fully investigated. We examined the effectiveness of anti-MIF antibodies on tumor growth and tumor-associated angiogenesis using murine colon cancer cell line, colon 26. We observed a significant inhibition of growth of tumors embedded on the back of BALB/c mice by treatment with anti-MIF antibodies. Next, we implanted a Millipore chamber filled with colon cancer cells in the subcutaneous fascia of the flanks of mice and then treated them with anti-MIF antibodies. We found that angiogenesis was markedly suppressed within the region of the subcutaneous fascia that was in contact with the chamber. To further assess the role of MIF in tumorigenesis, we established MIF transgenic mice, which demonstrated that tumor growth and the associated angiogenesis were significantly enhanced in comparison with control mice.

Animals↗
PubMed2003

[Analysis of factors affecting the course of renal disease progression in patients with established renal insufficiency].

All renal diseases ultimately progress to end-stage renal disease after renal dysfunction develops except for acute renal failure or rapidly progressive glomerulonephritis. However, renal function can be preserved for long periods in patients with mild renal insufficiency. We examined the factors affecting the progression of renal disease in patients with established renal insufficiency. We enrolled 38 patients with renal insufficiency diagnosed at the first visit and who were followed up for at least 3 years. We retrospectively recorded all information relating to serum creatinine and blood pressure levels during the follow-up periods. The patients were categorized as group A(n = 11), long-term renal survivors(at least 8 years), group B(n = 22), short-term renal survivors(3 to 8 years) and others(n = 5). Basal renal diseases were variable, and included IgA nephropathy, membranous nephropathy, focal segmental glomerulosclerosis, hypertensive glomerulosclerosis, tubulo-interstitial disease and lupus nephritis. Except for the degree of urinary occult blood, no other clinical data obtained at the first visit differed between groups A and B. Overall blood pressure levels throughout the entire clinical course also did not differ between the two groups. However, mean blood pressure levels before serum creatinine had reached the level of 2.0 mg/dl were significantly lower in group A compared with group B (96 +/- 7.8 vs. 103 +/- 6.3 mmHg, p < 0.05). We considered that the serum creatinine level of the so-called "point of no return" might be 2.0 mg/dl. In conclusion, blood pressure should be strictly controlled before serum creatinine levels reach 2.0 mg/dl.

Adult↗
PubMed2003

[Two cases of interstitial nephritis with primary Sjögren's syndrome successfully treated by steroid therapy].

We have experienced two cases of interstitial nephritis with Sjögren's syndrome successfully treated by steroid therapy. Case 1. A 50-year-old woman was admitted because of rash and arthralgia of the limb. Although her renal function was normal, serum IgG was extremely high and gallium-67 scintigrams indicated abnormal uptake in both kidneys with swelling on CT scans. Renal biopsy specimens showed a patchy dense interstitial infiltration of lymphocytes, monocytes and partly plasma cells with tubular cell atrophy. To suppress an excessive immune reaction, oral prednisolone was administrated at a dose of 30 mg/day. Six weeks after inception of the therapy, re-biopsy specimens showed a decrease in interstitial infiltration, particularly plasma cells, and interstitial fibrosis did not progress. After 8 weeks, the serum IgG level was normalized. Case 2. A 57-year-old woman was found to have renal involvement(serum creatinine level: 2.2 mg/dl) and anemia. Clinical findings suggested primary Sjögren's syndrome with renal tubular acidosis. Renal biopsy specimens showed a moderate to severe interstitial infiltration of inflammatory cells. After inception of steroid therapy(prednisolone 40 mg/day), renal involvement and renal anemia gradually improved. The renal function has been kept stable(serum creatinine level: 1.5 mg/dl) for 9 years by low-dose steroid therapy. These two cases suggest that steroid therapy plays two important roles: controlling of the acute immune reaction that causes renal fibrosis to progress in case 1, and long-term preservation of the renal function by the continuous use of low-doses in case 2.

Anti-Inflammatory Agents↗
PubMed2003

Induction of macrophage migration inhibitory factor by lysophosphatidic acid: relevance to tumor growth and angiogenesis.

Macrophage migration inhibitory factor (MIF) plays an important role not only in the immune system, but also in tumorigenesis. Lysophosphatidic acid (LPA), a unique lipid mediator, shares several biological functions with MIF, including promotion of tumor cell growth and associated angiogenesis. In this study, we investigated the signaling cross-talk between these two molecules during tumorigenesis and angiogenesis. We first examined the expression of MIF mRNA on a murine colon cancer cell line, colon 26, by LPA. We found that LPA enhanced the expression of MIF mRNA in a dose-dependent manner in vitro. In parallel, LPA stimulated cell growth and up-regulated the vascular endothelial growth factor (VEGF). These effects were dramatically blocked by 21 base double strand (ds) RNA specific for mouse MIF mRNA (RNAi). In vivo, colon 26 cells treated with MIF dsRNA were injected into the backs of mice. The size of tumor volumes became significantly smaller than that of controls. Angiogenesis examined by a Millipore chamber method was also suppressed by the MIF dsRNA. Next, we evaluated the signal transduction pathway relevant to the mitogen-activated protein kinase (MAPK) and Akt/PI3K pathways in response to LPA by RNAi. Ras activation and phosphorylation of Akt and ERK1/2 were strongly suppressed by the dsRNA. On the other hand, tyrosine phosphorylation was minimally changed by the treatment. Taken together, these results suggest that MIF could promote both tumor cell growth and angiogenesis induced by LPA via both the Ras-MAPK and Ras-Akt/PI3K signaling pathways.

Animals↗
PubMed2002

Synthesis and structure-activity relationships of novel 7-substituted 1,4-dihydro-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acids as antitumor agents. Part 1.

In an attempt to search for clinically useful antitumor agents, we have discovered that a series of 1,7-disubstituted-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids possessed moderate cytotoxic activity. We investigated the structure-activity relationships in this series of compounds by changing N-1 and C-7 positions and the core ring structure itself and evaluated the synthesized compounds against several murine and human tumor cell lines. These modifications led us to the following findings. (1) The 2-thiazolyl group at the N-1 position of the naphthyridine structure is the best substituent for antitumor activity. (2) Regarding core ring structure, the naphthyridine derivative is the most active followed by pyridopyrimidine analogue. (3) At the C-7 position, aminopyrrolidine derivatives are more effective than other amines or thioether derivatives. Finally, the trans-3-amino-4-methoxypyrrolidinyl derivative (43j) and the 3-amino-3-methylpyrrolidinyl derivative (43f) as well as 3-aminopyrrolidinyl derivative (AT-3639, 1) were determined to be effective in in vitro and in vivo antitumor assays, and their activity was comparable to that of etoposide.

Animals↗
PubMed2002

Klotho protein deficiency leads to overactivation of mu-calpain.

The klotho mouse is an animal model that prematurely shows phenotypes resembling human aging. Here we report that in homozygotes for the klotho mutation (kl(-/-)), alpha(II)-spectrin is highly cleaved, even before the occurrence of aging symptoms such as calcification and arteriosclerosis. Because alpha(II)-spectrin is susceptible to proteolysis by calpain, we examined the activation of calpain in kl(-/-) mice. m-Calpain was not activated, but mu-calpain was activated at an abnormally high level, and an endogenous inhibitor of calpain, calpastatin, was significantly decreased. Proteolysis of alpha(II)-spectrin increased with decreasing level of Klotho protein. Similar phenomena were observed in normal aged mice. Our results indicate that the abnormal activation of calpain due to the decrease of Klotho protein leads to degradation of cytoskeletal elements such as alpha(II)-spectrin. Such deterioration may trigger renal abnormalities in kl(-/-) mice and aged mice, but Klotho protein may suppress these processes.

Amino Acid Sequence↗
PubMed2002

Distribution of sialoglycoconjugates in the rat cerebellum and its change with aging.

We examined the distribution of sialoglycoconjugates in the cerebellum of 9-week-old and 30-month-old rats using light microscopy and electron microscopy in combination with two lectins, Maackia amurensis lectin (MAL) for Sia(alpha)2-3Gal and Sambucus sieboldiana agglutinin (SSA) for Sia(alpha)2-6Gal. Each lectin showed characteristic staining patterns. In young adult rats, MAL stained a strongly granular layer, a weakly molecular layer, and the medullary lamina, while SSA more strongly stained the medullary lamina than the molecular and granular layers. After aging, different staining patterns were obtained. Intense SSA reactivity was observed in the granular layer and intense MAL reactivity was observed in the medullary lamina of the aged groups. The reactivity of Purkinje cells with MAL was downregulated in the aged rats. These results indicated that Sia(alpha)2-3Gal and Sia(alpha)2-6Gal were expressed in distinct regions of the rat cerebellum and that their expression patterns changed in the aged brain.

Aging↗