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Biomedical subjects

R Sasaki

Publications and source records attributed to R Sasaki.

At least 73 records · Page 4Linked to original sources
PubMed1999

Production of a novel exopolysaccharide by Rahnella aquatilis.

A bacterium Tomakomai B-1 that was isolated from the activated sludge of a treatment process for wastewater of the pulp industry was found to produce soluble and insoluble exopolysaccharides (EPSs) when grown aerobically in a medium containing sucrose as the sole carbon source. The sugar component of soluble EPSs consisted of rhamnose, mannose, galactose, glucose, mannuronic acid, galacturonic acid and glucuronic acid, and that of insoluble EPSs consisted of rhamnose, mannose, galactose, glucose, mannuronic acid and glucuronic acid. The concentrations of insoluble and soluble EPS were approximately 1.63 and 2.58 g/l, respectively, by Erlenmeyer flask culture at 20 degrees C for 3 d with a synthetic medium containing 1% sucrose, 0.05% CaCO(3), 0.05% MgSO(4), 0.1% K(2)HPO(4), 0.0001% Na(2)MoO(4), 0.01% urea, 1.07% MES and small amounts of trace metals. Tomakomai B-1 was identified as Rahnella aquatilis. To our knowledge the production of EPSs by R. Aquatilis is reported here for the first time.

Journal Article↗
PubMed1999

UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6N-acetylglucosaminyltransferase holds a key role on the control of CD15s expression in human pre-B lymphoid cell lines.

Expression mechanism of CD15s (sialyl-Lex, sLex) antigen has been investigated using human B lymphoid cell lines. sLexstructures were not expressed in mature B lymphoids but highly expressed in pre-B leukemia and pre-B lymphoma cell lines. The expression site was mainly on the O -linked oligosaccharide chains and E-selectin mediated-cell adhesion capability of sLex-positive cells were significantly suppressed by benzyl-alpha-GalNAc treatment. Subsequently, the bases of the sLexexpression control mechanism were examined at the levels of enzymatic activities and transcripts of glycosyltransferases. (1) The activities of alpha1-->3fucosyltransferase, alpha2-->3sialyltransferase, beta1-->4Gal-transferase, and elongation beta1-->3GlcNAc-transferase, did not correlate with sLexexpression levels. (2) The transcripts of Fuc-TVII were not parallel with sLexexpression, and those of ST3Gal IV and beta1-->4Gal-transferase were constitutively detected in all cell lines tested. (3) There was no detectable enzyme activity for core 3 and 4 backbone structure synthesis in human B cell lines. (4) By contrast, the enzyme activities and transcripts of UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6 N -acetylglucosaminyltransferase (Core2GnT) had significant correlation with the cell surface expression of sLexantigen. (5) Moreover, Western blot analysis revealed the presence of a major approximately 150 kDa glycoprotein that carries O -linked oligosaccharides recognized by anti-sLexmonoclonal antibody in sLex-positive pre-B leukemia cell lines. This correlation of Core2GnT with CD15s expression suggests that Core2GnT is a regulator of the cell surface expression of sLexin human pre-B lymphoid cells.

Antigens, CD↗
PubMed1999

Microelectrophoretic analysis of changes in protein expression patterns in mouse oocytes and preimplantation embryos.

One- and two-dimensional polyacrylamide microslab gel electrophoresis followed by silver staining was devised to visualize picogram to nanogram levels of proteins and was applied to the analysis of 1-20 mouse oocytes and embryos (approximately 16.5-330 ng of protein) during preimplantation development. Compared with values in embryos, more bands in the higher molecular weight range were found only for unfertilized oocytes in one-dimensional microelectrophoresis. A marked decrease in the number of protein spots occurred after fertilization in two-dimensional microelectrophoresis. Both findings indicate a decrease in maternal proteins caused by fertilization. Silver-staining densities were almost invariable for 8 major spots, but increased, decreased, or varied for 32 minor spots in developing embryos from the 1-cell to the morula stage, signifying spot-specific changes in the expression of zygotic proteins during development. The protein patterns in cumulus cells and blastocysts were different from those in oocytes and embryos. Even in a single 1-cell embryo, major spots and some minor spots were detectable by our two-dimensional microelectrophoretic technique, but many more minor spots were visualized in five 1-cell embryos, exemplifying the limit of our microelectrophoretic technique. As a preliminary result, a two-dimensional immunoblot pattern is shown for glucose transporter 1 expressed in morulae.

Animals↗
PubMed1999

Increased serum levels of vascular endothelial growth factor in patients with renal cell carcinoma.

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. One such factor, vascular endothelial growth factor (VEGF), is considered to exert a potent angiogenic activity, as indicated by immunohistochemical and molecular evidence. In this study we investigated the serum VEGF level (s-VEGF) in patients with renal cell carcinoma (RCC). s-VEGF in peripheral blood samples was analyzed in 40 RCC patients and 40 patients without cancer (controls) using a sandwich enzyme-linked immunoassay. In 20 RCC patients, serum samples were obtained separately from the bilateral renal veins. s-VEGF was also measured before, 4 and 8 weeks after nephrectomy in 11 patients. There were significant differences in s-VEGF between the RCC patients and the controls (207.3+/-32.9 vs. 71.5+/-9.1 pg/ml, mean+/-SE) (P<0.005), between the tumor-bearing renal veins and the contralateral ones (P<0.01), between the pre- and post-nephrectomy situations (P<0.01) and among the various parameters of tumor status such as tumor extent (P<0.001) and existence of metastasis (P<0.001). s-VEGF significantly correlated with the tumor volume obtained by a three-dimensional measurement (r=0.802, P<0.0001). The sensitivity and specificity of s-VEGF at the cut-off level of 100 pg/ml, as determined by the receiver-operating-characteristics curve, were 80.0% and 72.5%, respectively. The results indicate that tumor tissue of RCC liberates VEGF into the systemic blood flow and that s-VEGF is a possible marker for RCC.

Adult↗
PubMed1999

A study on serum carotenoid levels in breast cancer patients of Indian women in Chennai (Madras), India.

Two-hundred and six breast cancer cases were histologically confirmed breast cancer diagnoses at the Cancer Institute in Chennai (Madras), India. One-hundred and fifty hospital controls were patients who had cancer at any site other than breast and gynecological organs, and 61 healthy controls were persons accompanying patients in the Cancer Institute. Serum levels of carotenoids such as beta-carotene, lycopene, cryptoxanthin, and zeaxanthin & lutein were determined by HPLC. Serum levels of total carotenes and total carotenoids including beta-carotene, which reflects food intake of colored vegetables and fruits and has a protective role for certain sites of cancer, were significantly lower among breast cancer cases and hospital controls compared to healthy controls, especially in post-menopausal women. Serum carotenoid levels appeared to change with menopausal status. Serum beta-carotene levels tended to be lower among breast cancer cases than among hospital controls in premenopausal women. Serum xanthophyll levels were significantly lower among breast cancer cases than among healthy controls in post-menopausal women, but not in premenopausal women. Serum levels of retinol and alpha-tocopherol among breast cancer cases were not significantly different from those in post-menopausal healthy controls, but were higher than those in hospital controls. Serum estrone levels were significantly higher among breast cancer cases than among healthy controls, but serum levels of estradiol and estriol were not. In conclusion, Indian women with cancer of breast or of other sites might have low intake of green-yellow vegetables rich in fiber and carotenoids such as beta-carotene and zeaxanthin & lutein.

Adult↗
PubMed1999

[Detection of prostate-specific antigen mRNA in preoperative peripheral blood of patients with prostate cancer: relationship to pathological parameters of the surgical specimens].

PURPOSE: Up to 40% of surgically treated prostate cancers are bound to be understaged by using current diagnostic modalities. To improve on current staging methods for prostate cancer, we evaluated whether nested reverse transcriptase-polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) mRNA can improve preoperative staging of prostate cancer. MATERIALS AND METHODS: From May 1996 through November 1997, 30 patients with prostate cancer (T1-T3) were evaluated for PSAmRNA in their peripheral blood by nested RT-PCR before radical retropubic prostatectomy. RESULTS: A highly sensitive RT-PCR assay employed detected one PSA-expressing cell (LNCaP) diluted into ten million mononuclear cells. All 15 controls, including 9 women, showed negative PSAmRNA in their peripheral blood, whereas 16 of 30 (53%) patients with prostate cancer showed positive PSAmRNA in their preoperative peripheral blood. Interestingly, 7 patients with positive PSAmRNA had pathologically organ-confined prostate cancer. No significant relationship was demonstrated between positive PSA-PCR results and clinico-pathological parameters such as clinical stage, pretherapeutic serum PSA, pathological stage, seminal vesicle invasion, lymph node metastasis, vascular invasion, or Gleason sum. CONCLUSION: Our present study showed that the results of PCR-based PSAmRNA assay had no significant association with clinico-pathological parameters. However, the prognostic significance of detecting the circulating prostate-specific signals requires a longer follow-up, which is currently under study.

Aged↗
PubMed1999

[Clinical results and prognostic factors of radiotherapy for bone metastases from breast cancer].

The purpose of this study was to analyze the results of initial radiotherapy for bone metastases (BM) from breast cancer and to investigate the prognostic factors. Between 1981 and 1995, 65 women (109 lesions) received initial radiotherapy for BM, aiming at a total dose of 50 Gy/25 Fr. Significant relief of pain was obtained in 61 (88.4%) of 69 estimable lesions according to the RTOG score. The control rates of pain including the prevention of pathological fractures or myelopathy were 80.4% at 5 years and 64.3% at 10 years. The median survival time of all patients was 11 months, and the survival rates were 56% at 1 year, 31.6% at 3 years, 17.9% at 5 years and 10.7% at 10 years, with five long-term survivors. Univariate analysis showed that a normal state of LDH, no other metastatic organs, a disease-free interval longer than two years, good performance status (0 or 1), BM limited to the axial bones, maintenance chemo-hormonal therapy and an age of more than 55 years were good prognostic factors. Multivariate analysis showed that LDH, age and performance status were significant predictors of prognosis. It is important to note the prognostic factors at the initial treatment of BM from breast cancer. We consider that further prospective studies are needed to determine the optimal treatment schedule, including radiotherapy and its combination with chemohormonal therapy, for BM.

Adult↗
PubMed1999

Erythropoietic, neurotrophic, and angiogenic functions of erythropoietin and regulation of erythropoietin production.

Stimulation of erythrocyte formation has been generally thought to be the sole physiological function of erythropoietin. Erythropoietin and its receptors, however, are also expressed in the central nervous system. In addition, erythropoietin is produced in the uterus in an estrogen-dependent manner. Novel functions of erythropoietin in these local sites are presented.

Central Nervous System↗
PubMed1999

[Optimal thoracic irradiation for stage IV lung cancer].

To investigate optimal thoracic irradiation (TI) for stage IV lung cancer, we retrospectively reviewed 150 patients. In all, 101 patients underwent radiotherapy for the primary lesion, and 130 had radiotherapy for metastasized sites. TI fields were basically divided into two groups; whole thoracic lesion irradiation (WTLI) and partial thoracic lesion irradiation (PTLI). Overall survival rates at 6 months, 1 year and 2 years were 58%, 27% and 11%, respectively, and MST was 7.1 months. There was no difference in survival according to histological type. On univariate analysis, the factors of good prognosis included good PS, free of bone metastasis, metastasis limited to a single organ, TI, chemotherapy, age (less than or equal to 75 years), and TN factors (T0-2 and N0-1). Multivariate analysis showed PS was the predominant factor. Among the patients treated with TI, survival rates of patients with PS 0-1 were superior to those of patients with PS 2-4. Radiation pneumonitis was more frequent in WTLI than in PTLI. The rates of thoracic failure death were 31.7% in patients treated with TI and 63.3% without TI. However, the size of the thoracic radiation field did not affect the rates of thoracic failure death. We concluded that TI for stage IV patients could reduce thoracic symptoms and increase the survival rate in the subgroup with good PS. Furthermore, we considered PTLI was worth while in the subgroup with poor PS.

Aged↗
PubMed1998

Erythropoietin prevents place navigation disability and cortical infarction in rats with permanent occlusion of the middle cerebral artery.

Erythropoietin (EPO) prevents the ischemia-induced delayed neuronal death in the hippocampal CA1 field in gerbils. EPO receptor (EPOR) is also expressed in the cerebral cortex but its function is not known. To examine whether EPO has a neuroprotective action in the cortex, EPO was infused into the cerebroventricles of stroke-prone spontaneously hypertensive rats with permanent occlusion of the left middle cerebral artery. Morris water maze test indicated that EPO infusion alleviated the ischemia-induced place navigation disability. The left (ischemic)-to-right (contralateral nonischemic) (L/R) ratio of cerebrocortical area in the EPO-infused ischemic group was larger than that in the vehicle-infused ischemic group. The occlusion caused secondary thalamic degeneration but infusion of EPO prevented the decrease in the L/R ratio of thalamic area and supported neuron survival in the ventroposterior thalamic nucleus. In situ hybridization indicated that EPOR mRNA was upregulated in the periphery (ischemic penumbra) of a cerebrocortical infarct after occlusion of the middle cerebral artery, suggesting that an increased number of EPOR in neurons facilitates the EPO signal transmission, thereby preventing the damaged area from enlarging.

Animals↗
PubMed1998

Estrogen-dependent production of erythropoietin in uterus and its implication in uterine angiogenesis.

Although erythropoietin (Epo) has been shown to possess in vitro angiogenic activity, its physiological significance has not been demonstrated. Normally angiogenesis does not occur actively in adults but an exception is the female reproductive organ. In the uterine endometrium, angiogenesis takes place actively for supporting the endometrial growth that occurs during transition from the diestrus to estrous stage. This transition is under control of 17beta-estradiol (E2), an ovarian hormone, and can be mimicked by injection of E2 to ovariectomized (OVX) mouse. Thus, the uterus is a pertinent site to examine the Epo function in angiogenesis. We found that Epo protein and its mRNA were produced in an E2-dependent manner, when the uterus from OVX mouse was cultured in vitro. The de novo protein synthesis was not needed for E2 induction of Epo mRNA. Administration of E2 to OVX mouse induced a rapid and transient increase in Epo mRNA in the uterus. Injection of Epo into the OVX mouse uterine cavity promoted blood vessel formation in the endometrium. Furthermore, injection of the soluble Epo receptor capable of binding with Epo into the uterine cavity of non-OVX mouse in diestrus stage inhibited the endometrial transition to proestrus stage, whereas heat-inactivated soluble Epo receptor allowed the transition to occur. These results, combined with our finding that the endothelial cells in uterine endometrium express Epo receptor, strongly suggest that Epo is an important factor for the E2-dependent cyclical angiogenesis in uterus.

Animals↗
PubMed1998

In vivo evidence that erythropoietin protects neurons from ischemic damage.

Erythropoietin (EPO) produced by the kidney and the liver (in fetuses) stimulates erythropoiesis. In the central nervous system, neurons express EPO receptor (EPOR) and astrocytes produce EPO. EPO has been shown to protect primary cultured neurons from N-methyl-D-aspartate (NMDA) receptor-mediated glutamate toxicity. Here we report in vivo evidence that EPO protects neurons against ischemia-induced cell death. Infusion of EPO into the lateral ventricles of gerbils prevented ischemia-induced learning disability and rescued hippocampal CA1 neurons from lethal ischemic damage. The neuroprotective action of exogenous EPO was also confirmed by counting synapses in the hippocampal CA1 region. Infusion of soluble EPOR (an extracellular domain capable of binding with the ligand) into animals given a mild ischemic treatment that did not produce neuronal damage, caused neuronal degeneration and impaired learning ability, whereas infusion of the heat-denatured soluble EPOR was not detrimental, demonstrating that the endogenous brain EPO is crucial for neuronal survival. The presence of EPO in neuron cultures did not repress a NMDA receptor-mediated increase in intracellular Ca2+, but rescued the neurons from NO-induced death. Taken together EPO may exert its neuroprotective effect by reducing the NO-mediated formation of free radicals or antagonizing their toxicity.

Animals↗
PubMed1998

Embryonal carcinoma P19 cells produce erythropoietin constitutively but express lactate dehydrogenase in an oxygen-dependent manner.

Embryonic stem cells and embryonal carcinoma P19 cells produce erythropoietin (Epo) in an oxygen-independent manner, although lactate dehydrogenase A (LDHA) is hypoxia-inducible. To explore this paradox, we studied the operation of cis-acting sequences from these genes in P19 and Hep3B cells. The Epo gene promoter and 3' enhancer from P19 cells conveyed hypoxia-inducible responses in Hep3B cells but not in P19 cells. Together with DNA sequencing and the normal transcription start site of P19 Epo gene, this excluded the possibility that the noninducibility of Epo gene in P19 cells was due to mutation in these sequences or unusual initiation of transcription. In contrast, reporter constructs containing LDHA enhancer and promoter were hypoxia inducible in P19 and Hep3B cells, and mutation of a hypoxia- inducible factor 1 (HIF-1) binding site abolished the hypoxic inducibility in both cells, indicating that HIF-1 activation operates normally in P19 cells. Neither forced expression of hepatocyte nuclear factor 4 in P19 cells nor deletion of its binding site from the Epo enhancer was effective in restoring Epo enhancer function. P19 cells may lack an unidentified regulator(s) required for interaction of the Epo enhancer with Epo and LDHA promoters.

Base Sequence↗
PubMed1998

Assessment of the expression of p53, MIB-1 (Ki-67 antigen), and argyrophilic nucleolar organizer regions in carcinoma of the extrahepatic bile duct.

BACKGROUND: The authors retrospectively examined the predictive value of p53, MIB-1, and the argyrophilic nucleolar organizer regions (AgNOR) and examined the relationships among them in carcinoma of the extrahepatic bile duct (EHBD). METHODS: Formalin fixed, paraffin embedded specimens from 54 patients with EHBD carcinoma were immunostained with MIB-1 against the Ki-67 nuclear antigen and p53 by the avidin-biotin peroxidase complex method, using the antigen retrieval technique of heating tissue sections in a microwave oven. The AgNOR proteins were localized at the optical level, as shown by a one-step silver staining technique. RESULTS: MIB-1 and AgNOR were closely associated with lymph node metastasis (P < 0.01). The cumulative survival rate for patients with a low MIB-1 labeling index (LI) (< 29%) was significantly better than that for patients with a high MIB-1 LI (> or = 29%) in cases of EHBD carcinoma (P < 0.05), but MIB-1 was not an independent prognostic factor in multivariate analysis. The results indicated that AgNOR and p53 overexpression had no prognostic value. The authors detected p53 in 24 of the 54 EHBD carcinomas (44.4%). There was a significant correlation between MIB-1 and AgNOR (P < 0.01). The authors found that neither MIB-1 nor AgNOR correlated with p53 overexpression. CONCLUSIONS: MIB-1 and AgNOR proved to be useful predictors of lymph node metastasis. The results of this study indicated that MIB-1 and AgNOR might be markers of the progression of EHBD carcinoma.

Adult↗
PubMed1998

Oral administration of a dominant T-cell determinant peptide inhibits allergen-specific TH1 and TH2 cell responses in Cry j 2-primed mice.

BACKGROUND: Oral immunotherapy with a peptide for allergic immune responses is theoretically a promising therapy but has not been established yet. OBJECTIVE: To evaluate immune suppressive efficacy of oral administration of an immunodominant peptide, we investigated changes in T-cell proliferation, TH1 - and TH2 -cytokine production, and TH1 - and TH2 -mediated antibody production in mice after oral administration of a peptide. METHODS: Peptide p246-259, containing a dominant T-cell determinant of Cry j 2, which is the major allergen in Japanese cedar pollen, was used in this study. Groups of mice received p246-259 or PBS alone before or after they were primed intranasally with Cry j 2 and cholera toxin. In another experiment mice were primed intraperitoneally with Cry j 2 and alum. Proliferative response and cytokine production by nasal-associated lymph node cells against Cry j 2 were investigated. Amounts of systemic anti-Cry j 2 IgE and IgG antibodies were also measured. RESULTS: Oral administration of the peptide to mice before, or even after, the sensitization induced oral tolerance in T-cell responses against the allergen; the tolerance was associated with decreased production of TH1 (IFN-gamma and IL-2) and TH2 (IL-4) cytokines. Allergen-specific TH1 -mediated (IgG2a and IgG2b) and TH2 -mediated (IgG1 and IgE) antibody responses were also inhibited. CONCLUSIONS: Oral administration of a dominant T-cell determinant peptide induces immunologic tolerance in both TH1 and TH2 cell responses against the whole protein allergen. Our study is the first, to our knowledge, to demonstrate the potential for peptide-based oral immunotherapy in order to treat allergic immune responses.

Administration, Intranasal↗