PubMed Health⌕ Search

Biomedical subjects

S Sugaya

Publications and source records attributed to S Sugaya.

At least 19 recordsLinked to original sources
PubMed2006

Endoscopic in vivo evaluation of tissue atypia in the esophagus using a newly designed integrated endocytoscope: a pilot trial.

BACKGROUND AND STUDY AIMS: A newly designed magnifying endoscope featuring an endocytoscopy function provided by ultrahigh magnification was evaluated in a pilot study in patients with various types of benign and malignant pathology in the esophagus. PATIENTS AND METHODS: Seventy-five consecutive patients were included in the study from 15 March to 21 December 2005. Twenty-nine patients with specific esophageal lesions that had been detected by regular or narrow-band imaging, or both, were further evaluated using endocytoscopy, followed by tissue biopsy or resection. During the endocytoscopic examinations, the esophageal mucosa was stained with 0.5 % methylene blue. The endocytoscopic findings were graded from 1 to 5 in an endocytoscopic atypia (ECA) classification. The final histopathological diagnoses based on biopsies or resected specimens were as follows: category 1 in the Vienna classification, n = 4; category 2, n = 6; category 3, n = 1; category 4, n = 10; and category 5, n = 7. The endocytoscopic diagnoses were compared with the histopathological diagnoses. RESULTS: Clear endocytoscopic images were obtained in all cases. In definitely malignant lesions, the cell nuclei had an enlarged and irregularly arranged appearance (grade ECA 5). The positive predictive value for malignancy (grades ECA 4 and 5) was 94 %; the false-negative rate was 16.7 %, and the false-positive rate was 6.3 %. The overall accuracy of endocytoscopy for differentiating between nonmalignant tissue (categories 1 - 3 in the Vienna classification) and malignant tissue (categories 4 and 5) was 82 %. CONCLUSIONS: These preliminary results suggest that incorporating endocytoscopy facilities into a standard endoscope may be helpful in characterizing tissue in a variety of esophageal lesions. The potential clinical impact of this method in relation to other gastrointestinal organs requires further study.

Carcinoma, Squamous Cell↗
PubMed2003

Involvement of LEU13 in interferon-induced refractoriness of human RSa cells to cell killing by X rays.

Culture of human cells with human interferon alpha and beta (IFNA and IFNB) results in increased resistance of the cells to cell killing by X rays. To identify candidate genes responsible for the IFN-induced X-ray resistance, we searched for genes whose expression levels are increased in human RSa cells treated with IFNA, using an mRNA differential display method and Northern blotting analysis. RSa cells, which showed increased survival (assayed by colony formation) after X irradiation when they were treated with IFNA prior to irradiation, showed increased expression levels of LEU13 (IFITM1) mRNA after IFNA treatment alone. In contrast, IF(r) and F-IF(r) cells, both of which are derived from RSa cells, showed increased X-ray resistance and high constitutive LEU13 mRNA expression levels compared to the parental RSa cells. Furthermore, the IFNA-induced resistance of RSa cells to killing by X rays was suppressed by antisense oligonucleotides for LEU13 mRNA. LEU13, a leukocyte surface protein, was previously reported to mediate the actions of IFN such as inhibition of cell proliferation. The present results suggest a novel role of LEU13 different from that in the inhibition of cell proliferation, involved in IFNA-induced refractoriness of RSa cells to X rays.

Antigens, Differentiation↗
PubMed2001

Mutagenicity of bisphenol A and its suppression by interferon-alpha in human RSa cells.

Bisphenol A is used as a monomer in the production of polycarbonate plastic products. The widespread use of bisphenol A has raised concerns about its effects in humans. Since there is little information on the mutagenic potential of the chemical, the mutagenicity of bisphenol A was tested using human RSa cells, which has been utilized for identification of novel mutagens. In genomic DNA from cells treated with bisphenol A at concentrations ranging from 1x10(-7) to 1x10(-5)M, base substitution mutations at K-ras codon 12 were detected using PCR and differential dot-blot hybridization with mutant probes. Mutations were also detected using the method of peptide nucleic acid (PNA)-mediated PCR clamping. The latter method enabled us to detect the mutation in bisphenol A-treated cells at a dose (1x10(-8)M) equivalent to that typically found in the environment. Induction of ouabain-resistant (Oua(R)) phenotypic mutation was also found in cells treated with 1x10(-7) and 1x10(-5)M of bisphenol A. The induction of K-ras codon 12 mutations and Oua(R) mutations was suppressed by pretreating RSa cells with human interferon (HuIFN)-alpha prior to bisphenol A treatment. The cells treated with bisphenol A at the concentration of 1x10(-6)M elicited unscheduled DNA synthesis (UDS). These findings suggested that bisphenol A has mutagenicity in RSa cells as well as mutagens that have been tested in these cells, and furthermore, that a combination of the PNA-mediated PCR clamping method with the human RSa cell line may be used as an assay system for screening the mutagenic chemicals at very low doses.

Avian Sarcoma Viruses↗
PubMed2001

Cyst-associated renal cell carcinoma: clinicopathologic characteristics and evaluation of prognosis in 27 cases.

BACKGROUND: No consistent clinicopathologic characteristics of cyst-associated renal cell carcinoma (CRCC) have previously been determined. METHODS: In total, 768 patients with renal cell carcinoma (RCC) underwent radical or partial nephrectomy. Renal cell carcinoma was classified as CRCC in 27 of these patients (3.5%, subdivided into RCC originating in a cyst and cystic RCC), clear-cell RCC in 662 patients (86.2%), chromophobe cell renal carcinoma in 36 patients (4.7%) and papillary RCC in 43 patients (5.6%) according to the criteria of the World Health Organization. RESULTS: The pathologic stage and nuclear grade were usually lower in those with CRCC (low stage/low grade; 89%/96%) or chromophobe cell renal carcinoma (low stage/low grade; 89%/80%) than in those with clear-cell RCC (low stage/low grade; 59%/65%) or papillary RCC (low stage/low grade; 53%/69%). Of the 27 CRCC patients, only 19 (70%) could be diagnosed through preoperative imaging studies. Patients with CRCC showed a favorable prognosis (survival rate: 95% at 1 year, 89.7% at 3 years and 84.4% thereafter) and, especially among the patients with RCC originating in a cyst, no cancer-related death was observed. Comparing the survival among four types of RCC, a favorable outcome was observed in cases of CRCC or chromophobe cell renal carcinoma compared with clear-cell RCC or papillary RCC (clear vs chromophobe: P = 0.002; chromophobe vs papillary: P = 0.019; clear vs cyst-associated: P = 0.001; papillary vs cyst-associated: P = 0.00079). CONCLUSIONS: In cases of CRCC, the disease was usually detected at lower stages and grades and therefore the prognosis was better than in cases of other types of RCC. Preoperative diagnosis of this disease was very difficult, especially in cases of RCC originating in a cyst.

Adenocarcinoma, Clear Cell↗
PubMed2001

Study on glutathionesulphonic acid as biodistribution promoter: concomitant use effect on verapamil hydrochloride and tegafur.

The effect of glutathionesulphonic acid (N-(N-gamma-L-glutamyl-L-beta-sulphoalanylglycine, GSO3H), which is one of the minor metabolites of glutathione (GSH), on the pharmacokinetics of verapamil hydrochloride (verapamil x HCl) and tegafur was investigated in rats. GSO3H was concomitantly used as sodium salt (GSO3Na). No significant change by the concomitant use of GSO3Na was recognized in the pharmacokinetics parameters of verapamil x HCl and tegafur, and plasma elimination of both substances was not affected by GSO3Na. The tissue-to-plasma concentration ratio (Kp) of verapamil x HCl in the lung 5 min after its administration under concomitant use of GSO3Na rose significantly, however, this effect disappeared 120 min after administration. No significant change was recognized in other organs. On the other hand, a significant difference of Kp of tegafur under a steady state concentration of GSO3Na was not recognized in any organs. It seemed that the elevation of a lipid solubility (oil water partition coefficient) of verapamil x HCl by the concomitant use of GSO3Na was related to the increase of the Kp value of verapamil x HCl in the lung. The partition coefficient of GSO3Na itself decreased when it was used concomitantly with verapamil x HCl.

Animals↗
PubMed2001

Increased and decreased expression of CD69 and CD23, respectively, in gravity-stressed lymphocytes.

BACKGROUND: Recent studies have shown that gravity-changing stress modulates expression levels of cell surface molecules on human lymphocytes. However, previous in vitro microgravity studies have been performed with lymphocytes treated with mitogenic agents. HYPOTHESIS: The aim of the study was to test if exposure of cells to gravity-changing stress alone alters the expression levels of cell surface molecules. Specifically, we examined whether the expression of activation markers is altered after exposure of lymphocytes to combinations of microgravity and hypergravity. METHODS: We used free-fall in parabolic flight for human subjects and a drop-shaft to expose peripheral blood mononuclear cells (PBMC) to gravity-changing stress. After such exposure, PBMC were isolated, and expression levels of CD69, CD23 and CD38 were estimated using three-color flow cytometry. RESULTS: Increased percentages of CD69-positive cells were observed with PBMC from 3 of 4 volunteers who undertook 10 parabolic flights. Exposure of blood to gravity-changing stress in the drop-shaft increased both ratios of CD69-positive cells and levels of CD69 expression on T and B cells. In contrast, the percentages of CD23-positive B cells was decreased. However, gravity-changing stress was not always followed by significant alteration in CD38 expression. CONCLUSIONS: Our findings suggest that CD69 and CD23 might be useful markers that are up- and down-regulated, respectively, after exposure of lymphocytes to gravity-changing stress.

ADP-ribosyl Cyclase↗
PubMed2001

Enhancement of protease activity involved in modulation of cell mutability by microgravity stress in UVC-irradiated human cells.

It is an intriguing question whether gravity-changing stress modulates human cell mutability. To resolve this problem, it is necessary to determine the cellular events leading to modulation. We previously detected protease activation just after UV (UVC, principally 254 nm wavelength) irradiation followed by hypomutability in cultured human cells. We here investigated whether UV-activated protease activity is affected in human UVAP-1 cells exposed to gravity-changing stress prior to UV irradiation.

Cell Line↗
PubMed2001

Modification of urinary secretion of 8-hydroxy-2'-deoxyguanosine and serum ACTH concentration following repetitive parabolic flights.

It is important to clarify the molecular mechanisms of physiological responses of the human body to changes in gravity. Previous reports demonstrated that gravity-changing stress increases the human urinary concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG). However, it has yet to be clarified whether repetitive parabolic flight modulates the urinary concentration of 8-OHdG after exposure to gravity-changing stress. In the present study, the effects of the number of previous experiences with parabolic flight on urinary excretion of 8-OHdG and concentration of serum ACTH were examined in 12 healthy volunteers.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Search for UV-responsive genes in human cells by differential mRNA display: involvement of human ras-related GTP-binding protein, Rheb, in UV susceptibility.

The search for genes responsible for the sensitivity of human cells to cell-killing effects of UV is an important area of biological research. To identify candidate genes responsible for UV sensitization, levels of mRNA expression were compared between UV-sensitive RSa cells and UV-resistant variant UV(r)-1 cells, using a differential display method and Northern blot analysis. Messenger RNA expression levels of human Ras homologue enriched in brain (Rheb) and/or a Rheb-like gene were up-regulated and slightly decreased in UV-irradiated RSa and UV(r)-1 cells, compared to in mock-irradiated cells, respectively. RSa and UV(r)-1 cells, both of which were treated with antisense oligonucleotides for Rheb RNA, exhibited an increased resistance to UV cell-killing. It remains unclear why UV(r)-1 cells are resistant to UV yet express Rheb mRNA at high levels. However, the results of antisense experiments together with the up-regulation in UV-irradiated RSa cells, suggest that Rheb is involved in the UV sensitization of both cells to UV cell-killing.

Cell Death↗
PubMed2000

Increase in ultraviolet sensitivity by overexpression of calpastatin in ultraviolet-resistant UVr-1 cells derived from ultraviolet-sensitive human RSa cells.

Human RSa cells are highly sensitive to apoptotic-like cell death by ultraviolet irradiation (UV) while UVr-1 cells are their variant with an increased resistance to UV. Three days after UV at 10 J/m2, the viability of RSa cells was approximately 17% while that of UVr-1 cells was 65%. This different survival might reflect apoptotic cell death since apoptosis-specific DNA ladder was more clearly observed in RSa cells than in UVr-1 cells after UV. Addition of ALLN/calpain inhibitor I to the culture medium after UV resulted in similar survival (14 - 18%) between RSa and UVr-1 cells. Immunoblot analysis showed down-regulation of protein kinase CTheta, Src, Bax and mu-calpain after UV was more prominent in UVr-1 than in RSa cells. Activated mu-calpain appeared within 1 h post-UV only in UVr-1 cells. The expression of calpastatin, a specific endogenous inhibitor of calpain, was higher in RSa than in UVr-1 cells. To further examine the role of calpain in UV-induced cell death, cDNA of human calpastatin was transfected into UVr-1 cells. The results showed that overexpression of calpastatin suppressed down-regulation of Src, mu-calpain and Bax. Concomitantly, colony survival after UV was reduced in calpastatin-transfected cells as compared to vector control cells. Our results suggest that activation of calpain might account for, at least in part, the lower susceptibility to UV-induced cell death in UVr-1 cells.

Apoptosis↗
PubMed2000

Isolation and characterization of a 60 kDa 2,4-D-binding protein from the shoot apices of peach trees (Prunus persica L.); it is a homologue of protein disulfide isomerase.

To obtain a candidate auxin-binding protein (ABP), a soluble 60 kDa protein was isolated from an extract of shoot apices of peach trees (Prunus persica L.) by affinity chromatography on a 2,4-dichlorophenoxyacetic acid (2,4-D)-linked Sepharose4B column. The 60 kDa polypeptide, designated Pp60, was purified as a single band on SDS-PAGE by column chromatography. Its dissociation constant (Kd) for [14C]-2,4-D was calculated to be 3.5 x 10(-5) M. The binding of Pp60 for [14C]-2,4-D was inhibited by naphthalene-1-acetic acid (NAA) and p-chlorophenoxyisobutyric acid (PCIB) as well as 2,4-D. Indole-3-acetic acid (IAA) had little effect on the binding. These results suggested that Pp60 is a protein that has an affinity for 2,4-D, NAA, and PCIB in vitro. The partial amino acid sequences of Pp60 showed high homology to those of protein disulfide isomerase (EC 5.3.4.1). Immunoblot analysis demonstrated that Pp60 exists ubiquitously in shoots and leaves. In fruit, expression of Pp60 is restricted at an early stage of development.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2000

Mutation modulating activity in human serum factors induced after parabolic flight.

We have reported that human interferon, one of cytokines present in serum, can confer hypomutability on various human cells. On the contrary, we have also reported that serum factors from cancer patients can enhance cell mutability. Therefore, it seems likely that cell mutability is changed by cytokine-like serum factors in our body. It is one of important space problems whether the mutability of human cells is regulated in response to microgravity and hypergravity (gravitational stress). However, there is little information about cell mutability during such stress. In this study, we investigated whether the mutability is changed by exposing cells to human serum factors after gravitational stress.

Adult↗
PubMed2000

Search for gravity-responsive genes by PCR-based mRNA differential display in human cells.

Mechanisms of molecular responses of human cells to gravity change and/or space radiation are one of the most important physiological problems in space science. We have previously reported that expression levels of several genes are changed in cultured human cells after UVC irradiation, and a few of those genes are responsible for UVC sensitivity. In this study, to find candidates for genes that play roles in susceptibility of human cells to gravity stressors, including those responsible for genetic stability in humans, we analyzed genes expressed differentially after gravity stress in human cells, using a PCR-based mRNA differential display (D.D.) method. Cells used were RSa and its variant cell lines, with discrepant sensitivity to radiation cell-killing and mutagenicity [correction of mutagenecity].

Cell Line↗