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Biomedical subjects

Seiji Saito

Publications and source records attributed to Seiji Saito.

17 recordsLinked to original sources

Comparison of completed and attempted suicide in Akita, Japan.

To determine the factors underlying suicide in Akita prefecture, a questionnaire survey was conducted among members of the Akita Prefectural Medical Association (APMA), regarding suicide cases they attended. During the investigation period (1 July 2001-30 June 2002), the total number of suicide cases was 243 (138 completed, 105 attempted). Significant differences were identified between completed and attempted suicide groups in terms of gender, age distribution, and suicidal methods. Specifically, in the completed suicide group, the number of male completers exceeded that of female completers, the number of middle-aged or elderly completers was high, and the majority of completed suicide cases involved hanging as the suicide method. Conversely, in the attempted suicide group, the number of female attempters exceeded that of male attempters, younger attempters were frequent, hanging was rare, and drug overdose or cutting was common. In addition, the number of cases involving a history of previous suicide attempts was significantly higher in the attempted suicide group than in the completed suicide group. The results of the present study support the concept that the completed and attempted suicide groups are essentially of a different nature. Furthermore, the number of cases involving a history of previous suicide attempts was found to be significantly lower in the completed suicide group than in the attempted suicide group. This result indicates the difficulty in decreasing the number of completed suicides by simply providing intervention and care for individuals who have attempted suicide.

Adolescent↗

Serum uric acid as an obesity-related indicator in early adolescence.

In adults, serum uric acid levels are positively correlated with body mass index (BMI) and hyperuricemia is considered to be a common lifestyle disorder related with obesity. However, the relation of serum uric acid levels with obesity has not been elucidated in children and adolescents. Serum uric acid levels were determined in 1,729 healthy children, consisted of 923 boys and 806 girls, aged 9.1 - 15.0 years. The incidence of hyperuricemia (defined as more than 7.0 mg/dl) in boys and girls were 8.8% and 0.6%, respectively. In 1,281 children out of all subjects, including 684 boys and 597 girls, height, weight, aspartate aminotransferase, and alanine aminotransferase were also determined and the correlations between serum uric acid levels and obesity were analyzed. BMI is popularly used as a standard indicator of obesity in adults. However, BMI increases without fat accumulation as children grow. In Japan, percentage of overweight (POW) is usually used as an alternative indicator for obesity. In general, children are evaluated as obesity, when POW is equal to or more than 20% (>or= 20%). Serum uric acid levels are positively correlated with obesity-related indicators, BMI and POW, in both boys and girls. Serum uric acid levels of the subjects with high POW (>or= 20%) are significantly higher than those of the subjects with low POW (< 20%) in both boys and girls. These results suggest that serum uric acid levels are significantly increased with obesity and could be used as one of obesity-related indicators even in early adolescence.

Adolescent↗

[Narrative-based medicine and clinical knowledge].

Narrative Based Medicine (NBM) can be defined as follows; a) It views the patient's illness as an unfolding story within the wider story of the patient's life and life-world; b) It acknowledges the patient as the narrator of the story and the subject of the tale; c) It recognizes that all medical theories, hypothesis and pathophysiologies as socially constructed narratives and accepts the coexistence of multiple different narratives; d) It regards the emergence of new stories from dialogue and discourse between patients and healthcare professionals as part of the treatment. Because psychiatry is the only area of specialist medicine where talking and listening are explicitly understood to be therapeutic, NBM can be adopted an effective perspective and method in psychiatry.

Narration↗

Arginine residue 155 in the second intracellular loop plays a critical role in rat melanin-concentrating hormone receptor 1 activation.

Melanin-concentrating hormone (MCH) receptor 1 (MCH1R) is a class A G protein-coupled receptor. The MCH system has been linked to a variety of physiological functions, including the regulation of feeding and energy metabolism. We recently reported the importance of a dibasic motif in the membrane-proximal C-terminal region for MCH1R function. Here we reveal that an Arg residue in intracellular loop 2 of MCH1R plays a critical role in receptor function. We analyzed the roles of two distinct motifs, BBXXB and BXBB (in which B is a basic residue and X is a nonbasic residue), located in the three intracellular loops of MCH1R. Triple-substitution mutants of intracellular loops 1 and 3 could still activate calcium mobilization, albeit with lower efficacy or potency. However, mutations in intracellular loop 2 led to a complete loss of induction of signal transduction without changing the high affinity constant (Kd) value. By analyzing a series of single-substitution mutants, a point mutation of Arg155 in intracellular loop 2 was found to be responsible for the signaling pathway elicited by MCH. In addition, substitution at positions corresponding to Arg155 in human MCH receptor 2 and rat somatostatin receptor 2 also markedly abolished their ligand-induced signaling capacities, indicating that this Arg is a recognition determinant in several G protein-coupled receptors.

Amino Acid Sequence↗

Recurrent URAT1 gene mutations and prevalence of renal hypouricemia in Japanese.

Recent identification of the urate transporter in the kidney (URAT1, encoded by SLC22A12) led to the molecular elucidation of idiopathic renal hypouricemia, which is a predisposition toward exercise-induce acute renal failure. One Japanese patient with renal hypouricemia demonstrated compound heterozygous mutations of the URAT1 gene (Q297X and IVS2+1G>A). It was suggested that these two mutations are recurrent mutations of the URAT1 gene in a Japanese population. In addition, we expect the prevalence of renal hypouricemia, 0.23%, from the analysis of serum urate levels in 1,730 Japanese children.

Acute Kidney Injury↗

Intermittent compressive strain may reduce aggrecanase expression in cartilage: a study of chondrocytes in agarose gel.

We tested the hypothesis that intermittent compressive strain reduces the catabolic actions of interleukin-1 beta on chondrocyte metabolism at the gene expression level. We investigated the effects of intermittent compressive strain on mRNA expression in bovine chondrocytes cultured in agarose gel supplemented with or without interleukin-1 beta. Fifteen percent compressive strain amplitude was applied to agarose-chondrocyte constructs at a frequency of 1 Hz. In the absence of interleukin-1 beta, the strain caused an increase in the mRNA levels of anabolic factors like aggrecan and Type II collagen, compared with the levels of anabolic factors in unstrained constructs. These results suggest that the strain may stimulate matrix production in normal cartilage. Interleukin-1 beta is a powerful catabolic agent; in unstrained agarose-chondrocyte constructs, interleukin-1 beta caused a decrease in the mRNA levels of anabolic factors. However, interleukin-1 beta also caused an increase in the mRNA of catabolic factors like aggrecanase-1, aggrecanase-2, and matrix metalloproteinase-3. In the presence of interleukin-1 beta, the strain reduced the mRNA levels of aggrecanase-1 and aggrecanase-2. These results suggest that intermittent compressive strain may protect cartilage by suppressing the expression of aggrecanase-1 and aggrecanase-2, which are thought to be the major matrix-degrading enzymes responsible for cleaving aggrecan.

Animals↗

Increased CD40 expression on articular chondrocytes from patients with rheumatoid arthritis: contribution to production of cytokines and matrix metalloproteinases.

OBJECTIVE: To examine expression of CD40 on articular chondrocytes derived from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and to investigate roles of CD40 on articular chondrocytes in production of inflammatory mediators associated with degradation of articular cartilage. METHODS: Articular cartilage samples were obtained from patients with RA and OA at total knee arthroplasty. Expression of CD40 on chondrocytes was examined using immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR), and flow cytometry. Tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), matrix metalloproteinase (MMP)-3, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 in culture supernatants of chondrocytes were measured by ELISA. RESULTS: Immunohistochemical staining revealed that CD40 was expressed on RA chondrocytes in vivo, but not in OA chondrocytes. RT-PCR and flow cytometry showed that cultured articular chondrocytes from RA patients, but not from OA patients, constitutively expressed CD40, and that interferon-gamma (IFN-gamma) enhanced the expression of CD40 on chondrocytes from both RA and OA patients. Membrane fraction of mouse myeloma Ag8 cells that was transfected with human CD154 (Ag8-hCD154) induced production of TNF-alpha, IL-6, and MMP-3 in RA chondrocytes, and pretreatment of RA chondrocytes with IFN-gamma enhanced the response. OA chondrocytes did not respond to stimulation with the membrane fraction of Ag8-hCD154 cells alone, but the cells did produce TNF-alpha, IL-6, and MMP-3 after pretreatment with IFN-gamma. CONCLUSION: CD40-CD154 interaction augments the expression of inflammatory cytokines and MMP in chondrocytes and contributes to an intrinsic process of cartilage degradation in RA.

Animals↗

Expression and function of the co-stimulator H4/ICOS on activated T cells of patients with rheumatoid arthritis.

OBJECTIVE: To investigate the expression and function of the inducible co-stimulator H4/ICOS in rheumatoid arthritis (RA) patients. H4/ICOS is the newest member of the CD28/CTLA-4 family to have been found to be expressed on activated T cells, and it participates in a variety of important immunoregulatory functions. METHODS: The levels of H4/ICOS expression on T cells among peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) from 28 patients with RA were analyzed by flow cytometry. To explore the role of H4/ICOS function in the inflammation of rheumatoid joints, lymphokine production by SF CD4+ T cells co-stimulated by H4/ICOS was assayed. Expression of H4/ICOS ligand (B7RP-1) mRNA in synovial tissues from patients with RA was examined by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: H4/ICOS-positive cells were increased significantly in whole, CD4+, and CD8+ T-cell fractions of SFMC compared with control PBMC. Comparison between control PB and PB from patients with active RA showed that H4/ICOS-positive whole and CD8+ T-cell fractions were increased significantly in the PB of RA patients. H4/ICOS costimulation clearly increased interferon-g, interleukin 4 (IL-4), and IL-10 production by SF CD4+ T cells. By RT-PCR, RA synovial tissue was shown to express mRNA of B7RP-1. CONCLUSION: Our results suggest that local immune responses may be modulated by H4/ICOS expressed on T cells in the joints of patients with RA, and thus H4/ICOS may be involved in the pathogenetic mechanism of RA.

Adult↗

Expression of granzyme B in human articular chondrocytes.

OBJECTIVE: To investigate the expression of granzyme B (GrB) in normal and rheumatoid arthritis (RA) articular cartilage, and to analyze the relationship between the expression of GrB and apoptotic chondrocytes in RA cartilage. METHODS: Normal cartilage samples were obtained from 9 resected joints and RA cartilage samples were obtained from 12 patients with RA during joint replacement surgery. Cartilage sections were analyzed by immunohistochemistry for the presence of GrB, and the mRNA expression of GrB in chondrocytes was analyzed by in situ hybridization and nonquantitative and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of perforin (PFN) was also assessed. Apoptotic chondrocytes were detected using TUNEL staining and their morphology was examined using electron microscopy. RESULTS: The immunohistochemical analyses revealed GrB and PFN expression in normal chondrocytes and a larger number of GrB and PFN-positive chondrocytes in RA cartilage. In situ hybridization and RT-PCR confirmed the expression of GrB and PFN mRNA, and semiquantitative RT-PCR showed elevated concentrations of GrB and PFN expression in RA chondrocytes. The distribution of GrB and PFN-positive cells in the RA cartilage samples was similar to that of apoptotic cells. CONCLUSION: GrB and PFN expression is present in normal human articular chondrocytes and elevated in RA chondrocytes. The targets and precise functions of GrB expressed in chondrocytes remain to be determined, but GrB may be involved in the remodeling mechanism of matrix macromolecules and the endogenous degradation of RA cartilage.

Antibodies↗

[The usefullness of hyaluronate injection in patients with RA].

In this seminar, we reported the usefulness of hyaluronate injection in clinical application with patients of RA. In basic research areas, however, the mechanisms responsible for the reported beneficial clinical effects of these treatments remain unclear. There is accumulating experimental evidence to show that the receptors of HA, eg, CD-44, accelerate the inflammation of joint. Administration high molecular weight HA may modulate CD-44 sensitive macromolecular in joint inflammation in part to reduce the activity of proteinases such as MMP-9.

English Abstract↗

Aberrant responsiveness to RANTES in synovial fluid T cells from patients with rheumatoid arthritis.

OBJECTIVE: To study expression and function of the chemokine receptor CCR5 in synovial fluid (SF) T cells from patients with rheumatoid arthritis (RA). METHODS: Expression of CCR5 was studied by flow cytometry and immunoblotting. The chemotactic response of T cells to chemokines was studied in cell migration assay. Tyrosine phosphorylation of Crk-associated substrate lymphocyte-type (CasL) was evaluated in immunoprecipitation and immunoblotting. RESULTS: SF T cells showed an increase in the population of CCR5, CXCR4, and CD45RO positive cells and exhibited an increase in chemotactic activity, which was not augmented with RANTES but stromal cell-derived factor-1alpha. Tyrosine phosphorylation per CasL molecule was markedly enhanced in SF T cells. In H9 cells, tyrosine phosphorylation of not only focal adhesion kinase but also CasL was induced after treatment with RANTES. Downmodulation of CCR5 by RANTES was decreased and recycling of CCR5 was accelerated in SF T cells when compared with peripheral blood (PB) T cells. When CD45RO positive PB T cells were cultured with interleukin 2, blunted responsiveness to RANTES-induced chemotaxis was reproduced as well as spontaneous chemotaxis, increased expression of CCR5, and aberrant receptor dynamics, after RANTES stimulation as observed in SF T cells. CONCLUSION: Synovial fluid T cells highly positive for CCR5 show aberrant characteristics; resistant to RANTES in terms of migration, but responsive in terms of dynamics of CCR5.

Arthritis, Rheumatoid↗

Comparison of metastatic behavior of parental and metastatic pancreatic cancer cell lines in Syrian golden hamsters.

The major cause of death in patients with pancreatic cancer is metastatic disease. In fact, at the time of diagnosis, patients usually have locally advanced or metastatic disease involving lymph nodes, liver, lungs or peritoneum. Therefore, for a better understanding of the tumoral behavior to design prevention or treatment strategies, in vivo models are important. We report here the results of the metastatic behavior of parental and metastatic cell lines in a hamster pancreatic cancer model when implanted orthotopically (OIH,OIM) or into the liver (LIH,LIM). Metastatic sites and survival were studied. Survival ranged from 72 to 105 days. The OIH group showed spontaneous metastases to lymph nodes. The second target organ was the lung. Liver metastases appeared earlier in the OIM group than OIH. LIH showed only metastases to the pancreas while the LIM group showed metastases to pancreas, vas deferens and testis. This study suggests that the metastatic behavior of parental and metastatic cell lines is different. Thus, this should be considered in the planning of clinical or surgical treatment against pancreatic cancer.

Adenocarcinoma↗

Antisense therapy specific to mutated K-ras gene in hamster pancreatic cancer model. Can it inhibit the growth of 5-FU and MMC-resistant metastatic and remetastatic cell lines?

UNLABELLED: K-ras point mutation at codon 12 has a relationship greater than 90% with pancreatic cancer. Cancer therapy should also include the treatment of metastatic disease because it is known that the properties of metastatic cells may vary considerably from those of the primary tumor. AIM: To clarify if the same drugs, which can inhibit the tumor growth in the parental cell line, can inhibit the pancreatic metastatic and remetastatic cell lines at the same concentrations and to compare the inhibition with antisense oligonucleotides mismatched to K-ras gene, in Syrian golden hamsters. MATERIALS AND METHODS: HaP-T1, a BHP-induced hamster pancreatic cancer cell line, MS-PaS-1 (a metastatic cell line established from "return trip" metastases from the liver to the pancreas) and MS-PaS-2 named as a "remetastatic cell line", i.e., metastases from MS-PaS-1 were used. MTT and MTT-agarose assays were performed, using 5-Fluorouracil (5-FU), Mitomycin C (MMC) and antisense oligonucleotide specific to K-ras oncogene. RESULTS: The inhibitory concentration (IC50) of 5-FU, which inhibited HaP-T1, had to be increased by 50-fold to inhibit MS-PaS-1 and 100-fold to inhibit MS-PaS-2. MMC had to be increased by 10-fold to inhibit MS-PaS-1 and 50-fold to inhibit MS-PaS-2. However, IC50 was the same when antisense oligonucleotide was tried in these 3 cell lines. CONCLUSION: Antisense oligonucleotide-targeted K-ras gene may be a good choice for therapy because it could inhibit the growth in metastatic and remetastatic cells as well as in primary tumor cells.

Animals↗

Suppression of invasion of a hamster pancreatic cancer cell line by antisense oligonucleotides mutation-matched to K-ras gene.

The anti-invasive activity of antisense oligonucleotides (ASO) specific to the K-ras gene in hamster pancreatic cancer was investigated. HaP-T1, a cell culture derived from BHP-induced hamster pancreatic cancer, was used. After liposome-mediated transfection with mutation-matched and mutation-mismatched ASO in different concentrations, cell proliferation was studied by MTT and MTT-agarose methods. In vitro chemoinvasion assay with the reconstitution of a matrix of a basement membrane onto a filter in a Boyden chamber was performed. Mutation-matched ASO inhibited the tumor growth and invasiveness of HaP-T1 in a dose-dependent manner, while mutation-mismatched ASO were not effective in inhibiting invasion. The present study suggests that antisense oligonucleotides mutation-matched to the K-ras gene may be a new anticancer strategy for pancreatic cancer since they inhibited not only tumor growth but also invasiveness in vitro.

Animals↗

Different pattern of metastasis in liver implanted pancreatic cancer between young and old Syrian golden hamsters.

We have previously reported on the "return trip" metastases from the liver to the pancreas in a hamster experimental pancreatic cancer model. Because the pancreas is the main metastatic site of liver-implanted pancreatic tumors, our aim was to clarify whether the metastatic sites differ in young and old tumor-bearing animals. HaP-T1, a continuous tissue-cultured cell line, derived from BHP-induced pancreatic adenocarcinoma, was implanted into the liver. The animals were divided into two groups: A) younger than 26 weeks and B) older than 26 weeks. Three animals from each group were sacrificed on Days 35, 42, 49, 56, 63, 70, 77, 84, 91 and 98, to study the metastatic sites. Survival was also studied. After death, necropsy was performed. Resected and necropsied specimens were analyzed histopathologically and by PCR/RFLP analysis to confirm the presence of K-ras point mutation. The success rate of implantation was 100%. Survival was 102.3+/-2.5 days in group A and 95.3+/-1.5 days in group B. Animals of group A, sacrificed weekly until Day 70, showed metastases only to the pancreas ("return trip"), while this phenomenon happened only in animals sacrificed on Day 35 in group B. In group A, on Days 77, 84, 91 and 98, metastases were also found in the kidneys, lymph nodes, ovary and testis. In hamsters of group B, metastases were found in multiple sites such as the pancreas, vas deferens, ovary and testis ("multiple journeys"). All intra-hepatically-implanted tumor and metastatic sites showed the K-ras point mutation. This homologous implantation model may be helpful for further research into the process of metastasis and its relationship with the immunological response.

Aging↗