Search PubMed⌕ Search

Biomedical subjects

S Tsunoda

Publications and source records attributed to S Tsunoda.

At least 91 records · Page 5Linked to original sources
PubMed1997

Analyses of human gliomas by restriction landmark genomic scanning.

The 16 primary gliomas were examined for changes in genomic DNA using a recently developed 2-dimensional gel electrophoresis method called restriction landmark genomic scanning (RLGS). This approach allows detection of DNA amplification, deletion, methylation and potentially other genetic rearrangements represented as decreases and increases in spot/fragment intensity on an autoradiogram. Approximately 2,000 landmark sites in tumor DNA were compared with those of DNA isolated from normal brain tissues. Seven spots showing intensified signal were consistently detected in at least 50% of tumors, implying activation of corresponding DNA sequences, and 8 additional spots having reduced signal were observed, again in more than 50% of all tumors, suggesting inactivation by the loss of 1 allele or homozygous deletion. Decreased signal may also infer relative CpG island methylation state. Of those spots consistently identified in tumors, 2 amplified and 4 reduced spots were found to be characteristic of low- and high-grade tumors, while the remaining 5 amplified and 4 reduced spots were associated with high-grade gliomas only, suggesting a link of specific mutations to degree of malignancy. A separate subset of glioblastomas evaluated, however, showed no alterations in these 'hot spots' which were detected in even low grade astrocytomas. The results demonstrate the genetic heterogeneity of glioblastoma and implicate the progression of neoplasia via differing genetic pathways.

Astrocytoma↗
PubMed1997

Genomic alterations in human glioma cell lines detected by restriction landmark genomic scanning.

Restriction landmark genomic scanning (RLGS) is a 2-dimensional gel analysis capable of detecting amplifications, deletions and rearrangements in genomic DNA. Using RLGS, we examined genomic DNA from each of 6 human-derived malignant glioma cell lines and from normal brain tissue samples. RLGS allows us to screen genomic DNAs as approximately 2,000 landmark sites in one procedure without any polymorphic markers. The resulting 2,000 spots in tumor samples were compared with those in normal brain. Six spots common to 5 of the 6 cell lines showed intensified signal, suggesting amplification of a tumor-specific DNA fragment. In addition, 25 spots common to 5 of the 6 lines showed a decrease in signal intensity, conversely indicating allelic loss of homozygous deletion. These results imply the existence of consistent genetic alterations in human glioma.

Brain Neoplasms↗
PubMed1997

Decreased expression of 20-kD homologous restriction factor (HRF20, CD59) on T lymphocytes in Epstein-Barr virus (EBV)-induced infectious mononucleosis.

HRF20 (CD59) is one of the membrane-associated complement regulatory proteins. The characteristic function of CD59 is to prevent membrane attack complex (MAC) formation on the cell surface and to protect the cell from complement-mediated cell lysis. We examined the expression of CD59 antigen on T cell subpopulations in patients with acute infectious mononucleosis (IM) and analysed the relationship between the amount of CD59 expression and activation-induced cell death of mature T cells with apoptosis. Decreased expression of CD59 on CD8+ T cells, especially on CD45RO+ and HLA-DR+ activated T cells, was marked in acute IM patients. In contrast, activated CD4+ T cells from IM patients expressed as much CD59 antigen as CD4+ T cells from healthy volunteers. After incubation-induced cell death, viable CD8+ T cells showed normal amounts of CD59 antigen on their surface. CD59dim CD8+ T cells were more susceptible to apoptosis than CD59bright CD8+ T cells. These findings suggest that decreased expression of CD59 on CD8+ T cells may discriminate the susceptibility of activated CD8+ T cells to activation-induced cell death in IM.

Acute Disease↗
PubMed1997

Thrombin stimulates production of transforming growth factor-beta by cultured human mesangial cells.

Fibrin formation within the glomeruli occurs in various forms of human and experimental glomerulonephritis and it may play an important role in progressive glomerular injury. Transforming growth factor-beta (TGF-beta) has been shown to participate in the glomerular accumulation of extracellular matrix in glomerulonephritis. We investigated whether thrombin, an important coagulation factor, could modulate the production of TGF-beta by cultured human mesangial cells (HMC). TGF-beta levels in the culture supernatants were measured by ELISA using a specific antibody. The TGF-beta concentration was significantly increased by incubation of HMC with thrombin in a time-dependent manner. The stimulating effect of thrombin on TGF-beta was inhibited by addition of hirudin (a natural thrombin inhibitor) and argatroban (a synthetic thrombin inhibitor). In addition DFP-inactivated thrombin, which has no enzymatic activity, did not stimulate TGF-beta production. A protein kinase C inhibitor (H7) and a tyrosine kinase inhibitor (herbimycin A) also inhibited thrombin induced TGF-beta production. These findings suggested that thrombin may modulate the synthesis of TGF-beta via protein kinase C- and tyrosine kinase-dependent mechanisms in cultured HMC. Thus thrombin may participate in the accumulation of extracellular matrix in glomeruli through the augmentation of TGF-beta production.

Cells, Cultured↗
PubMed1997

Decreased sympathetic outflow to muscles in patients with cervical spondylosis.

To clarify the pathogenesis of neurologic symptoms of a vascular nature that may accompany cervical spondylosis (CS), we measured the sympathetic outflow to muscles (muscle sympathetic nerve activity: MSNA) in 8 ambulatory patients with CS and 10 healthy volunteers (controls). The burst rate and incidence of MSNA at rest were significantly lower in patients with CS than in controls (P < 0.01). There were no differences between the 2 groups in either resting heart rate or blood pressure. During a head-up tilting, the changes in MSNA were slightly greater in CS patients than controls due to reduced baseline levels of MSNA in CS patients. The burst incidence of MSNA in CS was significantly negatively correlated with the severity of pyramidal tract symptoms (P < 0.05). The decreased MSNA at rest in CS patients may be due to a spinal cord compression resulting from posterior spondylotic changes in the cervical spine.

Aged↗
PubMed1997

Lecithinization of IL-6 enhances its thrombopoietic activity in mice.

This study was conducted to assess the merit of lecithinization of recombinant human interleukin-6 (IL-6) as a drug delivery system. IL-6 was lecithinized by covalently binding it with a phosphatidylcholine (lecithin, PC) derivative. The in-vivo thrombopoietic potency of lecithinized IL-6 (PC-IL-6) was greater than that of native IL-6 when administered subcutaneously, although the in-vitro bioactivity of PC-IL-6 was markedly reduced by lecithinization. When PC-IL-6 and native IL-6 were given in doses that produced the same level of thrombopoietic activity, the former stimulated less production of IgG1, a marker of the adverse effects of IL-6, than did the latter. Furthermore, PC-IL-6 persisted in the blood longer than native IL-6. Based on the above, PC-IL-6 appears to be useful as a drug delivery system and may also be useful in the treatment of drug-induced thrombocytopenia.

Animals↗
PubMed1997

Systemic lupus erythematosus associated with transverse myelitis and parkinsonian symptoms.

A 31-year old woman developed transverse myelitis after 10 years remission since she was first diagnosed as systemic lupus erythematosus. Although pulse methyl prednisolone resolved her myelitis, Parkinson-like symptoms developed subsequently after reduction of steroid. Treatments including apheresis did not improve her Parkinson-like symptoms such as rigidity, akinesia, impairment of speech and mask-like facial expression. Levodopa was effective as a symptomatic therapy. Orally administered cyclophosphamide eventually led her to remission and withdrawal from levodopa. Her clinical course and the absence of other possible causes prompted us to conclude that Parkinsonian symptoms as well as transverse myelitis may have developed as manifestations of central nervous system lupus.

Adult↗
PubMed1997

Transforming growth factor-alpha mRNA and epidermal growth factor receptor mRNA expression in normal and neoplastic mammary glands of four strains of mice with different mammary tumor potentials.

Transforming growth factor-alpha (TGF alpha) and epidermal growth factor receptor (EGF-R) mRNAs were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in the normal and neoplastic mammary glands of four strains of mice with different mammary tumor potentials (from highest to lowest potential): SHN, GR/A, SLN and C3H/He. At 2 months of age, when the mammary glands of these strains consisted mostly of normal tissue, the samples examined showed the positive expressions of both TGF alpha and EGF-R mRNAs in all strains (4-6 mice per group), except for EGF-R mRNA in the SLN mice, expressed in only 2 of 4 samples associated with no end-bud formation in the mammary glands. At 10 months, all of the samples from all four strains had a positive expression of TGF alpha mRNA. The EGF-R mRNA expression paralleled the degree of the formation of preneoplastic hyperplastic alveolar nodules (HAN) in all strains. These findings indicate that TGF alpha and EGF-R participate in the growth of the mammary glands, and that EGF-R especially contributes to the formation of end-buds at younger ages and to that of preneoplastic HAN at later ages. All of the samples of mammary tumors from four strains had positive expressions of both TGF alpha and EGF-R mRNAs.

Animals↗
PubMed1997

PEGylation of interleukin-6 effectively increases its thrombopoietic potency.

The in vivo thrombopoietic activity of polyethylene glycol-modified interleukin-6 (MPEG-IL-6), in which 54% of the 14 lysine amino groups of IL-6 were coupled with PEG, was compared to that of native IL-6. Native IL-6 and MPEG-IL-6, which showed about 51% of the specific bioactivity of native IL-6, were administered subcutaneously to mice every 2 days for 7 days. Native IL-6 increased not only the peripheral platelet count, but also the plasma-IgG1 level in a dose-dependent manner. MPEG-IL-6 showed about 500 times higher thrombopoietic potency than native IL-6. Further, in comparison to native IL-6, MPEG-IL-6 did not enhance IgG1 production as much as it enhanced platelet production. MPEG-IL-6 significantly stimulated platelet recovery in mice treated with 5-fluorouracil, whereas the administration of native IL-6 had a negligible effect. The plasma half-life of MPEG-IL-6 was about 100-fold longer than that of native IL-6. The decrease in the plasma clearance of MPEG-IL-6 was thought to be due, in part, to the shielding of the proteolytic sites in the IL-6 molecule by the PEG chain. The uptake of IL-6 by the reticuloendothelial system, such as the liver and spleen, was markedly limited by PEGylation. The PEGylation of IL-6 markedly enhanced the blood-residency of IL-6, resulting in effective augmentation of its thrombopoietic activity and a marked decrease in its side-effects. These findings suggest that MPEG-IL-6 may be a potential candidate for thrombopoietic agent.

Animals↗
PubMed1997

B cell malignancy and hepatitis C virus infection.

Italian authors report that hepatitis C virus (HCV) infection may be one of the causes of lymphoid malignancy such as non-Hodgkin's lymphoma (NHL) and Waldenström's macroglobulinemia (WM). To assess the relationship between HCV infection and B cell malignancy (BCM) in Japan, we analyzed HCV-RNA in 50 patients with BCM [25 cases of NHL, 4 of WM and 21 of multiple myeloma (MM)] and determined genotype of infected HCV(Okamoto's classification) using reverse transcription-polymerase chain reaction assay. Eight (16.0%) of 50 patients with BCM were HCV-RNA positive [HCV(+)], while no patients were HCV(+) in control group (18 patients of non-B cell NHL). Numbers of HCV(+) cases in each group examined were as follows; four (16.0%) in B cell NHL (genotype II/III/IV were 3/1/0, respectively), one (25.0%) in WM (genotype III) and three (14.3%) in MM (genotype II/III/IV were 1/1/1, respectively). All patients examined had no symptoms and signs suggesting vasculitis. The incidence of HCV infection in the patients with BCM was markedly higher than that (approximately 1%) of healthy blood donors in Japan. We also experienced four B cell NHL cases with splenic or hepatic origin in the course of chronic hepatitis C. These results implicate the association between persistent HCV infection and the occurrence of BCM.

Genotype↗
PubMed1996

Apoptosis of pregnancy-dependent mammary tumor and transplantable pregnancy-dependent mammary tumor in mice.

Pregnancy-dependent mammary tumors (PDMT) of GR/A mice and transplantable PDMT (TPDMT-4 line) in DDD mice, are exceptionally stable in hormone dependence, continue to grow until parturition and regress soon after delivery. In order to study the regression mechanism of PDMT and TPDMT-4, morphological and biochemical changes were examined in the tumors removed on day 18 (TPDMT-4) or day 20 (PDMT) of pregnancy, and on the expected parturient and the following postpartum days. DNA fragmentation occurred from day 18 (TPDMT-4) or day 20 (PDMT) of pregnancy to the day after parturition. Apoptotic cells were demonstrated by an in situ 3'-end labeling method, and the plateau of the number of apoptotic cells was observed on the parturient day in PDMT and on the day after parturition in TPDMT-4. Reverse transcriptase polymerase chain reaction showed that expression of Fas was slightly increased but that of bcl-2 was decreased during the process of involution of TPDMT-4 and PDMT. These results suggest that both an increase in expression of Fas and decrease in expression of bcl-2 are involved in the apoptosis of pregnancy-dependent mammary tumor cells after parturition.

Animals↗
PubMed1996

Relation of abnormal burst activity of spinal neurons to the recurrence of autotomy in rats.

Two groups of rats received different amounts of peripheral deafferentations; one group received sections of sciatic nerve (S-rats) and the other received sections of sciatic and saphenous nerves (SS-rats). In Experiment 1 the occurrence of autotomy was compared between S- and SS-rats for up to 70 days after the surgery. Autotomy in SS-rats frequently recurred until 40 days after denervation whereas in S-rats it scarcely recurred. In Experiment 2 spontaneous activity was recorded from the spinal cords in S- and SS-rats, and the proportion of burst firing cells (B-cells), characterized by periodic and high frequency bursts, was compared. In both S- and SS-rats with fresh wounds the occurrence of B-cells was high until 40 days after denervation. However, B-cells were still frequently observed in SS-rats with old wounds until 40 days after denervation, whereas B-cells were scarcely found in S-rats with similar old wounds. This finding corresponded well with the behavioral observation in Experiment 1. The data strongly suggests that the continuance of a high proportion of B-cells in the spinal cord plays an essential role for the induction of recurrent autotomy.

Afferent Pathways↗
PubMed1996

Alterations of retinoblastoma, p53, p16(CDKN2), and p15 genes in human astrocytomas.

BACKGROUND: Alterations of the suppressor genes, such as the retinoblastoma (RB), p53, p16(CDKN2), and p15 genes, have been reported in human gliomas. These genes have been suggested as the cell cycle regulatory genes at the G1-S checkpoint. METHODS: Alterations of the RB, p53, p16(CDKN2), and p15 genes in human astrocytomas were screened by single strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP analysis) and then confirmed by dideoxy sequencing. In addition, the expression of RB and p16 protein was examined by Western blot analysis. RESULTS: Aberrations of the RB gene were found in 3 of 23 surgical astrocytoma specimens (13%). Mutations were found at codon 754 in exon 22 (Val-->Gly), codon 519 in exon 17 (Thr-->Pro), and one base deletion at codon 903 resulting in stop codon at codon 905 in exon 26. These mutational locations were all near the regions associated with the functional domains of the RB gene. Aberrations of the p53 gene were found in 4 cases (17.4%). These mutations were found at codons 146 (Trp-->Gly) and 165 (Gln-->His) in exon 5, codon 73 (Val-->Glu) in exon 4, and codon 313 (Ser-->Asn) in exon 9. In addition, alterations of the p16(CDKN2) gene were found, with 5 cases (21.7%) having homozygous deletions, and 2 cases (8.7%) harboring point mutations. No p15 gene alteration was detected. The expression of p16 protein was undetectable in 10 cases (43.5%) by Western blot analysis, demonstrating an inverse correlation with the expression of RB protein. CONCLUSIONS: A few cases had overlapping alterations, and the incidence of one or more RB, p53, or p16(CDKN2) changes appeared to be relatively high in human astrocytomas. These results suggest that cell cycle regulatory gene alterations may play an important role in the development of gliomas.

Astrocytoma↗
PubMed1996

Absence of CD69 expression on peripheral eosinophils in episodic angioedema and eosinophilia.

A 45-year-old woman with episodic angioedema and eosinophilia is presented. CD69, which is one of the surface antigens of activated eosinophils, was not expressed on the peripheral eosinophils in this patient, in contrast to hypereosinophilic syndrome. This suggests that CD69, which is not dependent on eosinophil density, may be another useful activation marker of eosinophils to distinguish episodic angioedema and eosinophilia from hypereosinophilic syndrome.

Angioedema↗
PubMed1996

In vitro schedule-dependent interaction between paclitaxel and cisplatin in human carcinoma cell lines.

The schedule-dependent interaction of paclitaxel and cisplatin was studied in four human carcinoma cell lines: non-small cell lung cancer, A549; breast cancer, MCF7; ovarian cancer, PA1; and colon cancer, WiDr cells. The cells were exposed simultaneously to the drugs for 24 h and sequentially to paclitaxel first for 24 h followed by cisplatin for 24 h, or vice versa, and then incubated in drug-free medium for 4 and 3 days, respectively. Cell growth inhibition was then determined by the 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenyltetrazolium bromide (MTT) reduction assay. The effects of drug combinations at the IC80 level were analyzed by the isobologram method. On simultaneous exposure to paclitaxel and cisplatin, additive and subadditive (slight antagonistic) effects were observed in A549, MCF7, and PA1 cells, while sub-additive and protective (antagonistic) effects were observed in WiDr cells. On sequential exposure to paclitaxel first, followed by cisplatin, additive effects were observed in all cell lines. On sequential exposure to cisplatin first, followed by paclitaxel, additive effects were observed in PA1 cells, while additive, sub-additive, and protective effects were observed in A549, MCF7, and WiDr cells. These findings suggest that the interaction of paclitaxel and cisplatin is schedule- and cell line-dependent. The optimal schedule of this combination may be paclitaxel first followed by cisplatin.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Schedule-dependent interaction between paclitaxel and 5-fluorouracil in human carcinoma cell lines in vitro.

We assessed the cytotoxic interaction between paclitaxel and 5-fluorouracil administered at various schedules against four human carcinoma cell lines, A549, MCF7, PA1 and WiDr. The cells were exposed simultaneously to paclitaxel and to 5-fluorouracil for 24 h or sequentially to one drug for 24 h followed by the other for 24 h, after which they were incubated in drug-free medium for 4 and 3 days respectively. In another experiment, the cells were exposed simultaneously to both agents for 5 days. Cell growth inhibition was determined by MTT reduction assay. The effects of drug combinations at IC80 were analysed by the isobologram. The cytotoxic interaction of paclitaxel and 5-fluorouracil was definitely schedule dependent. Simultaneous exposure to paclitaxel and 5-fluorouracil for 24 h showed mainly subadditive effects in A549, MCF7 and WiDr cell lines, whereas it showed additive effects in PA1 cells. Sequential exposure to paclitaxel followed by 5-fluorouracil showed additive effects in all cell lines. Sequential exposure to 5-fluorouracil followed by paclitaxel showed subadditive effects in A549, MCF7 and PA1 cells. Whereas it showed additive effects in WiDr cells. These findings suggest that maximum cytotoxic effects can be obtained when paclitaxel precedes 5-fluorouracil. Interestingly, the continuous (5-day) exposure to paclitaxel and 5-fluorouracil had additive effects in A549, PA1 and WiDr cells, indicating that the prolonged simultaneous administration of these agents may circumvent the antagonistic interaction produced by short-term simultaneous administration. These findings may be useful in clinical trials of combination chemotherapy with paclitaxel and 5-fluorouracil.

Antimetabolites, Antineoplastic↗
PubMed1996

Molecular design of hybrid tumour necrosis factor-alpha. II: The molecular size of polyethylene glycol-modified tumour necrosis factor-alpha affects its anti-tumour potency.

To design hybrid tumour necrosis factor-alpha (TNF-alpha) applicable to systemic anti-tumour therapeutic use, we assessed the relationships among the molecular size of hybrid TNF-alpha, in vitro bioactivity and in vivo anti-tumour potency. Natural human TNF-alpha was covalently modified with polyethylene glycol (PEG) of various number-average molecular weights (Mn = 2000, 5000, 12,000). The in vitro bioactivity of PEG-modified TNF-alpha s decreased with an increase in the degree of PEG modification, irrespective of the molecular weight of PEG. This decrease in the specific bioactivity markedly increased with an increase in the molecular weight of the attached PEG. The in vivo anti-tumour effects of the hybrid TNF-alpha s with a molecular size from 100 to 110 kDa, which had more than 50% of specific bioactivity of native TNF-alpha, were significantly superior to other PEG-TNF-alpha s. These hybrid TNF-alpha s showed over ten times greater anti-tumour effects than native TNF-alpha. Thus, the molecular size, which was determined by the degree of PEG modification and PEG molecular weight, influences the specific activity and anti-tumour effects of hybrid TNF-alpha.

Animals↗