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Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 289 records · Page 16Linked to original sources
PubMed2000

[Some geographical features of the location and gene mutation of cancers occurring in Nantong City, China].

OBJECTIVE: To detect the location and geographical features of gene mutation of the cancer based on 30,709 clinical tumor biopsies. METHODS: Thirty thousand seven hundred and nine cases of tumor biopsy materials were collected from the Department of Pathology of Nantong Cancer Hospital between June 1974 and December 1987. The address of the village and county of patients was collected and statistical analysis was performed on data from lab examination. DNA sequencing of 31 cases of hepatocellular carcinoma (HCC) was performed at the Department of Pathology of the Medical College of Tokyo University, Japan. RESULTS: The data suggested that different carcinomas occurred predominantly in some districts and the frequency and type of mutation of the P53 gene in the HCC were different in different districts. CONCLUSION: It seems that based on the clinical biopsy materials, carcinomas of the uterus cervix (CC) and nasopharynx tend to occur in some districts of Nantong City and the frequency and type of mutation of the gene P53 of the HCC were different in different districts. The reason for this is not understood and further study will be done.

China↗
PubMed1999

The hydrophobic residues phenylalanine 184 and leucine 187 in the type-1 parathyroid hormone (PTH) receptor functionally interact with the amino-terminal portion of PTH-(1-34).

Recent mutagenesis and cross-linking studies suggest that three regions of the PTH-1 receptor play important roles in ligand interaction: (i) the extreme NH(2)-terminal region, (ii) the juxtamembrane base of the amino-terminal extracellular domain, and (iii) the third extracellular loop. In this report, we analyzed the second of these segments in the rat PTH-1 receptor (residues 182-190) and its role in functional interaction with short PTH fragment analogs. Twenty-eight singly substituted PTH-1 receptors were transiently transfected into COS-7 cells and shown to be fully expressed by surface antibody binding analysis. Alanine-scanning analysis identified Phe(184), Arg(186), Leu(187), and Ile(190) as important determinants of maximum binding of (125)I-labeled bovine PTH-(1-34) and (125)I-labeled bovine PTH-(3-34) and determinants of responsiveness to the NH(2)-terminal analog, PTH-(1-14) in cAMP stimulation assays. Alanine mutations at these four sites augmented the ability of the COOH-terminal peptide [Glu(22), Trp(23)]PTHrP-(15-36) to inhibit the cAMP response induced by PTH-(1-34). At Phe(184) and Leu(187), hydrophobic substitutions (e.g. Ile, Met, or Leu) preserved PTH-(1-34)-mediated cAMP signaling potency, whereas hydrophilic substitutions (e.g. Asp, Glu, Lys, or Arg) weakened this response by 20-fold or more, as compared with the unsubstituted receptor's response. The results suggest that hydrophobicity at positions occupied by Phe(184) and Leu(187) in the PTH-1 receptor plays an important role in determining functional interaction with the 3-14 portion of PTH.

Amino Acid Substitution↗
PubMed1999

Dominant and shared T cell receptor beta chain variable regions of T cells inducing synovial hyperplasia in rheumatoid arthritis.

Previously, we demonstrated the presence of at least two distinct subpopulations of patients with rheumatoid arthritis (RA) employing a cell-transfer experiment using severe combined immunodeficient (SCID) mice. One group of patients, whose T cells derived from the rheumatoid joints, induced synovial hyperplasia (SH) in the SCID mice (the positive group). The other group did not display the induction of SH (the negative group). TCR/Vbeta gene usage analysis indicated that some dominant T cell subpopulations were oligoclonally expanding only in the rheumatoid joints, and not in the periphery of the patients of the positive group. Moreover, these T cell subpopulations were not seen in the joints of patients in the negative group or in non-RA patients. In addition, the preferential uses of certain TCR/Vbetas (Vbeta8, Vbeta12, Vbeta13, and Vbeta14) genes were demonstrated in these T cells. In this study, to investigate whether these T cells are driven by a certain antigen(s), the third complementarity determining regions (CDR3s) of TCR/Vbeta, especially Vbeta8 and Vbeta14 PCR products, were cloned and sequenced. As a result, a dominant CDR3 sequence, CASS-PRERAT-YEQ, was found in Vbeta14+ T cells from the rheumatoid joint of a patient (Patient 1) of the positive group with a Vbeta14 skew. The identical CDR3 sequence also predominated in Vbeta14+ T cells from the rheumatoid joint of another patient (Patient 7) of the positive group with a Vbeta14 skew. In addition, in the patients (Patients 4, 7, 8) of the positive group with a Vbeta8 skew, other dominant CDR3 sequences, CASS-ENS-YEQ and CASS-LTEP-DTQ, were found as in the case of Vbeta14. However, no identical CDR3 sequences were detected dominantly in the joints of the patients in the negative group or in non-RA patients. A Vbeta14+ T cell clone (TCL), named G3, with the identical CDR3 sequence, CASS-PRERAT-YEQ, was isolated successfully from Patient 1, and cell transfer of G3 with autologous irradiated peripheral mononuclear cells induced SH in the SCID mice. Taken together, these results suggest that T cells inducing SH, thought to be pathogenic for RA, might be driven by a certain shared antigen(s).

Amino Acid Sequence↗
PubMed1999

Decrease in susceptibility toward induction of apoptosis and alteration in G1 checkpoint function as determinants of resistance of human lung cancer cells against the antisignaling drug UCN-01 (7-Hydroxystaurosporine).

7-Hydroxystaurosporine (UCN-01) is a protein kinase inhibitor that is under development as an anticancer agent in the United States and Japan. Long-term exposure of human A549 non-small cell lung cancer cells to UCN-01 furnished cells (A549/UCN) with acquired resistance against UCN-01. In this study, the sensitivity of these cells toward the growth-arresting properties of certain conventional cytotoxic agents was explored. Cells were not cross-resistant against adriamycin, Taxol, staurosporine, and UCN-02, but they displayed 14- and 4.4-fold resistance against cisplatin and mitomycin C, respectively. Previous studies on the mechanism(s) of action of UCN-01 suggest that induction of apoptosis and G1 phase accumulation are important for its anticancer activity; therefore, we compared induction of apoptosis and cell cycle distribution caused by UCN-01 in wild-type A549 and A549/UCN cells using flow cytometry. UCN-01 (0.4 microM) induced apoptosis (62% terminal deoxynucleotidyl transferase-mediated nick end labeling-positive cells) in A549 cells, but not in A549/UCN cells. The percentages of cells that accumulated in G1 when exposed to UCN-01 (0.4 microM) were 22% in A549 cells and 67% in A549/UCN cells. These results suggest that acquired resistance of cancer cells against UCN-01 is characterized by attenuation of apoptosis induction associated with reinforcement of the G1 checkpoint and that apoptosis regulation is drastically altered in A549/UCN cells as compared with A549 cells. Cyclin-dependent kinase (CDK) inhibitor proteins p21 and p27 in A549/UCN cells were up-regulated, which was accompanied by overexpression of G1 cyclins D1 and E, but UCN-01 hardly affected levels of these proteins. In contrast, cyclin A, cyclin B1, retinoblastoma, and CDK2 proteins were apparently down-regulated, without changes in CDK4/6. UCN-01 hardly affected the expression level of cyclin B1 and induced dephosphorylation of retinoblastoma in both cell types. UCN-01 induced down-regulation of cyclin A level and CDK2 activity accompanied with its dephosphorylation in A549/UCN cells, but not in A549 cells. The antiapoptotic protein bcl-2 was apparently up-regulated in A549/UCN cells, however, bcl-xL, another antiapoptotic protein, was down-regulated, without changes in bak and bax. Taken together, these results are consistent with the notion that induction of apoptosis and block of cell cycle in G1 are important determinants of the sensitivity of cancer cells to UCN-01 and suggest that inhibition of CDK2 activity accompanied by its dephosphorylation and decrease of expression level of cyclin A might play an important role in the G1 phase accumulation induced by UCN-01.

Alkaloids↗
PubMed1999

Induction of antitumor immunity with Fas/APO-1 ligand (CD95L)-transfected neuroblastoma neuro-2a cells.

Fas/Apo-1 (CD95)-Fas ligand (FasL) system has been implicated in the suppression and stimulation of immune responses. We examined the induction of antitumor immunity with neuroblastoma Neuro-2a cells transfected with FasL cDNA (Neuro-2a+FasL). Neuro-2a+FasL cells expressed FasL on the cell surface and secreted soluble FasL. Histologic and flow cytometric analyses revealed that Neuro-2a+FasL cells caused neutrophils to infiltrate into the injected site, resulting in strong inflammation. Neutrophil infiltration was inhibited by treatment with anti-FasL mAb and did not occur in Fas-deficient lpr mice. Normal syngeneic mice rejected Neuro-2a+FasL cells after the inflammation and acquired tumor-specific protective immunity. CD8+ T cells were responsible for the antitumor immunity. Neuro-2a+FasL cells formed tumors after far longer latency compared with mock-transfected Neuro-2a+Neo cells in nude mice, and immune competent mice rejected Neuro-2a cells but not sarcoma S713a cells when they were injected with Neuro-2a+FasL cells in a mixture. These results suggest that neutrophils attracted through the Fas-FasL system may impair tumor cells by inflammation at the initial step, followed by development of CD8+ T cell-dependent tumor-specific antitumor immunity, leading to complete eradication of tumor cells. Importantly, the treatment with Neuro-2a+FasL cells exhibited therapeutic efficacy against growing tumors.

Animals↗
PubMed1999

Hypertonicity stimulates taurine uptake and transporter gene expression in Caco-2 cells.

The osmoregulation of taurine transport in intestinal epithelial cells was investigated using human intestinal Caco-2 cells. The activity of taurine transport in the Caco-2 cells was increased by hypertonic conditions. This hypertonicity-induced up-regulation was dependent on both the culturing time and the osmotic pressure. Hypertonicity did not affect the activity of L-leucine, L-lysine, or L-glutamic acid transport, suggesting that osmoregulation was specific to taurine transport. The intracellular taurine content of Caco-2 cells was also increased by culturing in a hypertonic medium. These hypertonicity-induced changes in the intracellular taurine content and transport activity were reversible. A kinetic analysis of taurine transport in the control and hypertonic cells suggested that the up-regulation was associated with an increase in the amount of the taurine transporter. The mRNA level of the taurine transporter in hypertonic cells was markedly higher than that in the control cells, indicating that this osmotic regulation was due to the increased expression of the taurine transporter gene.

Caco-2 Cells↗
PubMed1999

Escherichia coli cafA gene encodes a novel RNase, designated as RNase G, involved in processing of the 5' end of 16S rRNA.

We found that the Escherichia coli cafA::cat mutant accumulated a precursor of 16S rRNA. This precursor migrated to the same position with 16.3S precursor found in the BUMMER strain that is known to be deficient in the 5' end processing of 16S rRNA. Accumulation of 16. 3S rRNA in the BUMMER mutant was complemented by introduction of a plasmid carrying the cafA gene. The mutant type cafA gene cloned from the BUMMER strain had a 11-bp deletion in its coding region. A small amount of the mature 16S rRNA was still formed in the cafA::cat mutant. This residual activity was found to be due to RNase E encoded by the rne/ams gene by rifampicin-chase experiments of the cafA::cat ams1 double mutant. These results indicated that the cafA gene encodes a novel RNase responsible for processing of the 5' end of 16S rRNA.

Bacterial Proteins↗
PubMed1999

Gene for a protein capable of enhancing lateral root formation.

Analysis of genes preferentially expressed in hairy roots caused by infection with Agrobacterium rhizogenes has provided insights into the regulation of lateral root formation. A hairy root preferential cDNA, HR7, has been cloned from hairy roots of Hyoscyamus niger. HR7 encodes a novel protein partially homologous to a metallocarboxypeptidase inhibitor and is expressed exclusively in the primordium and base of lateral roots in hairy roots. Overexpression of HR7 in transgenic roots of H. niger dramatically enhances the frequency of lateral root formation. The results of this study indicate that expression of HR7 plays a critical role in initiating lateral root formation.

Amino Acid Sequence↗
PubMed1999

Expression of the c-fos gene induced by parathyroid hormone in the bones of SAMP6 mice, a murine model for senile osteoporosis.

SAMP6 mice are a murine model for senile osteoporosis, characterized by low peak bone mass seen at 4 or 5 months of age. Parathyroid hormone (PTH)-induced c-fos expression was examined in the bones, bone-marrow cells and kidney tissues of 2-month-old male SAMP6 mice. SAMP2 mice, which have a higher peak bone mass, were used as controls. The expression of c-fos in the bone peaked at 30 min after 60 microg/kg of human PTH(1-34) administration. After peaking, the expression fell quickly in SAMP2 mice. This decrease in expression was delayed in SAMP6 mice and the expression was higher at 1 h than in SAMP2 mice. The phenomenon observed in the bone appears to be tissue specific as it was not seen in the bone-marrow cells or kidney tissue. Immunohistochemical studies showed that c-Fos protein was localized to the nuclei of some of the osteocytes and a few of the osteoblasts in the cortical bone, and that osteocytes expressing c-Fos protein increased after PTH treatment. These results suggest that osteocytes might contribute to the maintenance of higher levels of c-fos expression in the bones of SAMP6 mice and may be related to cortical osteopenia in these mice by modulating bone remodeling and/or modeling.

Animals↗
PubMed1999

Clear cell carcinoma has an expression pattern of cell cycle regulatory molecules that is unique among ovarian adenocarcinomas.

BACKGROUND: The purpose of this study was to identify biologic differences between ovarian clear cell carcinoma and other ovarian adenocarcinomas by comparing the expression of cell cycle regulatory molecules and by analyzing the survival of the patients. METHODS: In 51 cases of epithelial ovarian carcinoma, the expression of the cell proliferation marker Ki-67 and that of the cell cycle regulatory molecules p53, p16, p21, p27, cyclin E, and cyclin A was studied using immunohistochemical techniques. The correlations among clinical stage, histologic subtype, labeling index for Ki-67, and expression of these cell cycle regulators were examined statistically. Multivariate survival analysis was performed using these factors in the Cox proportional hazards model. RESULTS: Clear cell carcinoma revealed such trends as low expression of both p53 and cyclin A and significantly increased expression of both p21 and cyclin E (compared with the other histologic subtypes). In all ovarian carcinomas, a very strong positive correlation (correlation coefficient 0.79; P < 0.0001) between p53 positive staining and cyclin A positive staining and a weak positive correlation (correlation coefficient 0.47; P < 0.01) between p21 positive staining and cyclin E positive staining were recognized at the level of expression of cell cycle regulatory molecules. Clinical stage was the only independent predictive factor for the survival of the patients. CONCLUSIONS: Among ovarian adenocarcinomas, clear cell carcinoma exhibits a unique pattern of expression of cell cycle regulatory molecules, though in this study the survival of the patients did not correlate with histologic subtype, only with clinical stage.

Adenocarcinoma↗
PubMed1999

Metallothionein does not protect mouse endocrine cells from damage induced by alloxan injection.

Effects of metallothionein (MT) on pancreatic endocrine cells of mice, injected with alloxan and at different zinc status were studied. Mice were given drinking water containing four different concentrations of zinc (0, 0.05, 0.1 or 0.5%) for 18 days, and alloxan was injected once on the 14th day. When zinc was added to the drinking water, pancreatic zinc and MT contents increased after injection of alloxan, but did not change with injection of vehicle alone, except in the group of mice drinking 0.5% zinc in water. However, plasma glucose level was increased in all the alloxan injected groups, and was independent of their zinc status. In mice given water with 0.5% of zinc, both pancreatic zinc and MT contents were higher than control mice given water alone. There was no difference in zinc and MT contents of the pancreas in mice drinking 0.5% zinc in groups injected with either alloxan or vehicle. The increase in plasma alpha-amylase activity, an indicator of pancreatic exocrine toxicity, was observed only in mice drinking water with 0.5% zinc after injection of both alloxan and vehicle. Histochemically, degranulation of zymogen and duct-like structures of exocrine cells and atrophy and disappearance of islet cells were observed in alloxan-injected mice drinking 0.5% zinc in water. The zymogen degranulation was observed on the vehicle-injected mice drinking 0.5% zinc in water. MT was immunohistochemically detected in the exocrine cells of both alloxan- and vehicle-injected mice given 0.5% zinc in water. No MT was detected in islet cells of mice in any group. The results show that an increase of zinc content may be followed by induction of MT synthesis in the pancreas of mice given increasing amounts of zinc in drinking water. However, MT dose not provide any protection against damage caused by alloxan to endocrine cells of the pancreas.

Alloxan↗
PubMed1999

Neuroleptics with differential affinities at dopamine D2 receptors and sigma receptors affect differently the N-methyl-D-aspartate-induced increase in intracellular calcium concentration: involvement of protein kinase.

This study examined the effect of chronic antipsychotic treatment on the NMDA-elicited changes in intracellular free Ca2+ concentration ([Ca2+]i) in the primary culture of rat frontal cortical neurons. Antipsychotics used in the study were chosen for their differential affinities at dopamine D2 receptors and sigma receptors. The potential involvement of protein kinases in this action of antipsychotics were also examined. Chronic treatment of cells with antipsychotics (sulpiride, clozapine, and chlorpromazine) which are known to be potent dopamine D2 receptor ligands, whereas possessing low or no appreciable affinity for sigma receptors, caused a dose-dependent potentiation of the NMDA-induced increase in [Ca2+]i. On the contrary, haloperidol, which is as potent a sigma receptor ligand as a dopamine D2 receptor ligand, did not affect the NMDA-elicited increase in [Ca2+]i. Sulpiride increased the maximum effect afforded by different concentrations of NMDA and shifted the dose-response curve of NMDA to the left (EC50 value from 12.5 microM to 1.39 microM). Consistent with sulpiride's affinity at dopamine D2 receptors, this action of sulpiride was stereoselective: S(-)-sulpiride was active whereas R(+)-sulpiride was inactive. Treatment of cells with dopamine (3 microM) tends to decrease the NMDA-induced increase in [Ca2+]i. Sulpiride at 1 microM totally abolished this action of dopamine and restored its potentiating action on the NMDA-induced increase in [Ca2+]i. Haloperidol, a potent dopamine D2 and sigma receptor ligand, did not affect the sulpiride's potentiating action on the NMDA-induced responses. On the other hand, chronic treatment of cells with a sigma receptor agonist, DTG, at a concentration producing no effect of its own (10 nM), led to an enhancement of the potentiating effect of sulpiride on NMDA-induced increase in [Ca2+]i. This action of DTG was abolished by haloperidol. Further, chronic, but not acute, treatment of cells with either a protein kinase inhibitor H-7 or a cAMP-dependent protein kinase (PKA) inhibitor H-89 abolished this effect of sulpiride on the NMDA-induced [Ca2+]i changes. These results indicate that the action of NMDA in the primary cortical neurons are regulated differently by ligands with differential affinities at dopamine D2 and sigma receptors. The results with protein kinase inhibitors indicate that the potentiation of NMDA responses by sulpiride involves intracellular biochemical events.

Animals↗
PubMed1999

Telomerase-independent senescence of human immortal cells induced by microcell-mediated chromosome transfer.

Maintenance of telomeres, commonly through expression of telomerase activity, is necessary but may not be sufficient for human cells to escape from the cellular senescence program and become immortal. We report here that human tumor cells could undergo cellular senescence in the presence of telomerase activity when a specific normal human chromosome was introduced via microcell-mediated chromosome transfer. The cell models studied include SiHa (uterine cervical carcinoma cells expressing E6 and E7 oncoproteins of human papillomavirus type 16) with a transferred chromosome 2, CC1 (choriocarcinoma cells expressing an amino-terminally truncated p53 protein) with a transferred chromosome 7, and JTC-32 (bladder carcinoma cells) with a transferred chromosome 11. The microcell hybrids with the indicated chromosomes ceased to divide after five to 10 population doublings and showed senescence-associated beta-galactosidase activity but still expressed the genes encoding three components of human telomerase, consistent with the retention of telomerase activity. These results are evidence for barriers to human cell immortalization, which involve activation of unidentified senescence-inducing genes that function independently of inactivation of telomerase.

Cell Line, Transformed↗
PubMed1999

A study on the differences between oral squamous cell carcinomas and normal oral mucosas measured by Fourier transform infrared spectroscopy.

We investigated the differences of Fourier transform infrared (FTIR) spectra between oral squamous cell carcinoma (OSCC) and normal gingival epithelium (NGE) or normal subgingival tissue (NST). We used 15 specimens of OSCC which had not been treated before measurement and 10 of NGE or NST. We also used cultured oral squamous cell carcinoma (COSCC) and the tissue (MSCC) which massed for 3 months after the cultured oral squamous cell carcinoma was transplanted into the lower back of a rat. Those tissue spectra were compared with the purified human collagens and human keratin. One half of every tissue specimen was measured with FTIR and the other half was investigated histologically. The differences of FTIR spectra between OSCC and NGE were observed in the bands between 1431 and 1482 cm(-1) and between 1183 and 1274 cm(-1). The shoulder at 1368 cm(-1) tended to disappear in OSCC, and the peaks at 1246 and 1083 cm(-1) found in NGE tended to shift to those at 1242 and 1086 cm(-1) in OSCC, respectively. The infrared spectrum of NST was noticed to be strongly influenced by the presence of collagen. Significant differences were also observed in the second derivative FTIR spectra between OSCC and NGE. Our data suggested that this infrared technique is applicable to clinical diagnostics.

Adolescent↗
PubMed1999

Modulation of intestinal functions by food substances.

The small intestinal epithelium plays a crucial role in the digestion/modification of food components, absorption of nutrients and recognition of food-derived signals. It also acts as a barrier against unfavourable materials in food. These intestinal functions may be influenced by food substances. In this paper, the effects of various food substances on the intestinal functions, particularly the absorption functions, are discussed. A new assay method, using a monolayer culture system of human intestinal epithelial cells, is applied to examine food-derived substances which could modulate the tight junction (TJ). Capsianoside, a diterpene glycoside from sweet pepper, was isolated and identified as one of the TJ-modulating substances. Those substances can be expected to facilitate the paracellular absorption of small molecular functional substances such as bioactive oligopeptides. The use of a human intestinal cell culture system also enabled us to make a simple screen test for food substances which affect the intestinal transporter functions. Substances which could suppress the activity of intestinal glucose transporters, for example, can be expected to reduce the dietary glucose uptake in the intestinal epithelium and control the blood glucose level. Polyphenolic compounds from plants, including green tea, were found to have such activity. Modulation of the brush border enzymes by food substances is also discussed.

Animals↗
PubMed1999

Free and protein-bound insulin-like growth factor-I (IGF-I) and IGF-binding proteins in plasma of coho salmon, Oncorhynchus kisutch.

Total and free insulin-like growth factor-I (IGF-I) levels were quantified in plasma from growth hormone (GH)-treated and fasted coho salmon. Total IGF-I was measured by radioimmunoassay after acid-ethanol extraction and free IGF-I was separated from protein-bound IGF-I using ultrafiltration by centrifugation. Total and free IGF-I increased in plasma after GH treatment and decreased after fasting. The level of free IGF-I, however, was maintained at approximately 0.3% in both experiments. Unsaturated binding activity in plasma for IGF-I was assessed by incubation with (125)I-recombinant salmon IGF-I ((125)I-sIGF-I). Although there was no difference in binding activity between GH-treated and control fish, fasted fish showed higher binding activity than did fed fish, suggesting induction of unsaturated binding protein by fasting. IGF-binding protein (IGFBP) bands were observed in plasma of coho salmon by Western ligand blotting using (125)I-sIGF-I. A low-molecular-weight (22 kDa) band was clear in fasted fish but not detectable in fed fish. The IGFBP band, which has molecular weight similar to that of human IGFBP-3 (41 kDa), was more intense in GH-treated fish than in controls. The molecular distribution of IGF-I in plasma was examined by gel filtration under neutral conditions. Most IGF-I was eluted around 40 kDa. This result suggests that the major form of bound IGF-I in the circulation of coho salmon may be in a 40-kDa binary complex rather than in a 150-kDa ternary complex, as in mammals.

Animals↗