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Biomedical subjects

S Itoh

Publications and source records attributed to S Itoh.

At least 235 records · Page 13Linked to original sources
PubMed1997

Ethyl nitrosourea and methyl methanesulfonate mutagenicity in sperm and testicular germ cells of lacZ transgenic mice (Muta Mouse).

The germ cell mutagens ethyl nitrosourea (ENU) and methyl methanesulfonate (MMS), were tested for their genotoxicity in sperm cells and testicular germ cells using lacZ transgenic mice (Muta Mouse). Eight- to 10-week-old Muta mice were treated with ENU (150 mg/kg) or MMS (40 mg/kg) by intraperitoneal injection. Three and 14 days after treatment, testes and sperm were collected for lacZ mutation analysis. Sperm were isolated from the epididymis and vas deferens by washing out the minced tissue. Germ cell DNA was isolated from testicular germ cells and sperm with the help of 2-mercaptoethanol, and the target lacZ gene, which is integrated into a lambda shuttle vector, was recovered by in vitro packaging. The resultant phages were allowed to infect to E. coli C (galE), and the lacZ mutant plaques were dominantly selected on a plate containing phenyl-beta-D-galactoside. Spontaneous mutant frequencies (MF) in vehicle-treated control mice were approximately 1 x 10(-5) and 3 x 10(-5) in testicular germ cells and sperm, respectively, at both sampling times. ENU treatment increased the MF in the testicular germ cells to 5 x 10(-5) on days 3 and 14, but did not affect sperm MF. MMS was not mutagenic in either tissue. The peripheral blood micronucleus assay was performed on the same animals 48 h after treatment, and strong inductions of micronucleated reticulocytes (MNRETs) were observed in both ENU- and MMS-treated mice. These data suggest that agents mutagenic to premeiotic germ cells, e.g., ENU, can be detected by transgenic mutation assay system using germ cells isolated from the testis. On the other hand, those mutagenic to postmeiotic cells, e.g., MMS, are insensitive in the assay system.

Animals↗
PubMed1997

Germ cell mutagenesis in lacZ transgenic mice treated with methyl methanesulfonate.

Mutagenesis induced by methyl methanesulfonate (MMS), a germ cell mutagen, in the testis and the sperm isolated from epididymis and vas deferens have been investigated using lacZ transgenic mice (Muta Mouse). Male Muta Mice were injected intraperitoneally with MMS at a dose of 80 mg/kg, a potent dominant lethal dose. Animals were killed on days 3 and 7 (Experiment 1) or days 10 and 14 (Experiment 2) after the treatment. Mutant frequencies (MFs) in the testis, sperm and spleen (Experiment 2 only) were analyzed by the positive selection system using E. coli C (GalE-) strain and phenyl beta-D-galactoside. The spontaneous MFs in the testis and sperm were 2.0-3.1 x 10(-5). No induction of mutation in the testis or sperm of the MMS-treated groups was observed at any sampling point. In the spleen, the spontaneous MF was approximately twice as high as that in the germ cells although the MF at each sampling point was almost the same as the spontaneous MF. MMS is known as a potent clastogen from the results of the dominant lethal assay and the micronucleus assay. The reason for the discrepancy between the results of these assays and the present results may have been insensitivity of the in vitro packaging to large deletion due to the failure to rescue the large deleted gene. It is suggested that the transgenic mouse assay using the in vitro packaging can not replace the dominant lethal assay in the case of MMS.

Animals↗
PubMed1997

Isolation of a promoter region in mouse cytochrome P450 3A (Cyp3A16) gene and its transcriptional control.

An 11.5 kb fragment of the mouse Cyp3a16 gene containing the 5' flanking region was isolated from the lambda DASHII mouse genomic library. A part of the 5' flanking region and the first exon of Cyp3a16 gene were sequenced. S1 mapping analysis showed the presence of two transcriptional initiation sites. The first exon was completely identical to Cyp3a16 cDNA. The identity of 5' flanking sequences between Cyp3a16 and Cyp3a11 genes was about 69%. A typical TATA box and a basic transcription element (BTE) were found as seen with other CYP3A genes from various animal species Moreover, some putative transcriptional regulatory elements were also found in addition to the sequence motif seen for the formation of Z-type DNA. To examine the transcriptional activity of Cyp3a11 gene, DNA fragments in the 5'-flanking region of the gene were inserted front of the luciferase structural gene, and the constructs were transfected in primary hepatocytes. The analysis of the luciferase activity indicated that the region between -146 and -56 was necessary for the transcription of CYP3a16 gene.

Animals↗
PubMed1997

Gene structure of mouse Cyp3a11: evidence for an enhancer element within its 5' flanking sequences.

A mouse Cyp3a11 gene was isolated from a mouse sperm DNA library with mouse Cyp3a11 cDNA as a probe. The nucleotide sequences determined for the gene and the 5' flanking region revealed that the mouse Cyp3a11 gene was composed of 13 exons and 12 introns. The exons spun about 23 kb. The nucleotide sequence of the exons was completely identical to Cyp3a11 cDNA. Within the 5' flanking sequence, putative binding sites of several transcriptional factors were found. Transient transfection assays were carried out with HepG2 cells, a human hepatoma cell line, using constructs containing different lengths of 5' flanking sequence fused to a reporter, chloramphenicol acetyltransferase gene. The results showed that a cis-acting element(s) was located from -1609 to -907.

Animals↗
PubMed1997

Simultaneous expression of ferredoxin, ferredoxin reductase and P450 in COS7 cells.

cDNA fragments encoding mouse ferredoxin and ferredoxin reductase were simultaneously introduced into COS7 cells by using an expression vector, pUC-SR alpha plasmid. When using the mitochondrial fraction prepared from the transfected cells, cytochrome-c reductase activity was detected. This activity was highest when 7.5 micrograms of the ferredoxin expression plasmid (pSR alpha F) and 2.5 micrograms of the ferredoxin reductase expression plasmid (pSR alpha FR) were transfected into COS7 cells. In this system, NADPH could be replaced by NADH as a cofactor for the reduction of cytochrome-c although the cytochrome-c reductase was more dependent on NADPH than NADH at a low concentration. When CYP24 expression plasmid was transfected into COS7 cells along with both pSR alpha F and pSR alpha FR, the transfected cells revealed a 3-fold higher 25-hydroxyvitamin D3-24-hydroxylase activity than COS7 cells transfected with CYP24 expression plasmid.

Animals↗
PubMed1997

Effect of pre-induction of heat shock proteins on indomethacin-induced small-intestinal lesion in rats.

Systemic hyperthermia induces the synthesis of heat shock proteins (HSPs) in several organs. However, the mechanism of induction and the functions of HSPs in the small-intestinal mucosa have not been established. We examined the expression of HSPs in the small-intestinal mucosa after systemic hyperthermia, and evaluated the cytoprotective function of pre-induced HSPs on experimentally induced mucosal damage. HSP expression was investigated by Western blot and densitometric analysis before and after hyperthermia (42.5 degrees C; 20 min). Expression of a 72-kDa heat shock protein (HSP72) and a 73-kDa heat shock protein (HSP73), both of which are endogenous cytoprotectants in vitro significantly increased, peaking 6-9 h after hyperthermia, without any pathologic alterations, whereas the expression of a 60-kDa heat shock protein (HSP60) did not increase. To investigate the influence of pre-induction of HSPs on small-intestinal damage, rats received indomethacin (10 mg/kg; orally) with or without pre-treatment with hyperthermia. Small-intestinal damage caused by indomethacin was not influenced by pre-induction of HSP72 and HSP73. We demonstrated that systemic hyperthermia induced HSP72 and HSP73, although pre-induction of these proteins did not have a cytoprotective function in the small-intestinal damage caused by indomethacin.

Animals↗
PubMed1997

Synergistic effects of Actinobacillus suis cells in combination with 5-fluorouracil on mice bearing murine L1210 leukemia cells.

The mean survival rates of female BDF1 mice transplanted intravenously (i.v.) with murine L1210 leukemia cells were significantly prolonged by intraperitoneal (i.p.) pretreatment (before i.v. transplantation) or by i.p. pre- and post-treatment (before and after the i.v. transplantation) with heat-killed Actinobacillus suis cells ATCC 15557 (AS 15557) alone, as compared with untreated L1210-leukemia-cell-bearing control mice. However, significant prolongation of the mean survival rates was not elicited by the i.p. post-treatment with AS 15557 alone. When 5-fluorouracil (5-FU) was applied i.p. to mice receiving post-treatment with AS 15557 alone, the mean survival rates of the L1210-leukemia-cell-bearing mice were significantly prolonged. The antileukemic action of AS 15557, alone or in combination with 5-FU, against L1210 leukemia was superior to that of a streptococcal preparation (OK-432) and was almost the same as of bacillus Calmette-Guérin with or without 5-FU. The results suggest the possibility that the synergism of AS 15557 in combination with 5-FU may be dependent on the relationship between the indirect immunological function of AS 15557 and the direct cytotoxic action of 5-FU on L1210 leukemia cells.

Actinobacillus↗
PubMed1997

Aggravation of the nutcracker syndrome during pregnancy.

BACKGROUND: The nutcracker syndrome is a rare condition thought to be caused by compression of the left renal vein between the descending aorta and the superior mesenteric artery. CASE: Gross hematuria appeared in the third trimester of an otherwise normal pregnancy. It continued despite treatment, and a cesarean was performed at 37 weeks' gestation. The hematuria stopped postpartum. With postpartum angiography and three-dimensional computed tomography, the diagnosis of nutcracker syndrome was finally made. CONCLUSION: Pregnancy can aggravate the nutcracker syndrome. This syndrome should be recognized as one of the diseases that causes gross hematuria.

Adult↗
PubMed1997

Effects of prostaglandin E1 infusion on limb hemodynamics and vasodilatory response in patients with arteriosclerosis obliterans.

It is well known that prostaglandin E1 (PGE1) increases peripheral blood flow. The aim of this study was to investigate the effects of PGE1 infusion on the hemodynamics and vasodilatory response of the leg affected by intermittent claudication in patients with arteriosclerosis obliterans (ASO). Fourteen legs of 8 male patients with ASO were infused intravenously with PGE1 (120 microg/day) for 7 consecutive days. Before the infusion and 5 days after cessation of the infusion, resting skin and skeletal muscle blood flow in the calf and occlusion-induced reactive hyperemic flow were measured using plethysmography and a laser Doppler flowmeter. Clinical symptoms in the legs were assessed by treadmill exercise testing. Resting calf blood flow was found to have increased significantly (skin, from 2.6 +/- 0.1 ml/min/100 g tissue to 2.9 +/- 0.1 ml/min/100 g tissue, p < 0.02; skeletal muscle, from 3.1 +/- 0.2 ml/min/dl tissue to 4.0 +/- 0.5 ml/min/dl tissue, p < 0.02). There was also a significant reduction in the peripheral vascular resistance (-17.8 +/- 7.2%, p < 0.05) 5 days after the cessation of infusion. The time to the half-maximum post peak of hyperemia was significantly elongated (from 34.6 +/- 5.7 sec to 58.6 +/- 9.2 sec, p < 0.01). Borg's score of the legs on exercise testing was markedly reduced, and symptom-free walking distance was increased by an average of 70.9 + 15.6%. In conclusion, PGE1 infusion has vascular effects on not only resting calf blood flow but also hyperemic flow responses. These retentive effects may be due to alteration in vascular functions and/or rheological state as a result of PGE1-induced regular enhancement of blood flow, rather than the direct vasodilatory effect of the agent.

Aged↗
PubMed1997

Effect of preinduction of heat shock proteins on acetic acid-induced colitis in rats.

In order to study the cytoprotective function of heat shock proteins (HSPs) in vivo, the effect of preinduction of HSPs by hyperthermia on acetic acid-induced colitis was investigated. Expression of 60-kDa, 72-kDa, and 90-kDa heat shock proteins (HSP60, HSP72, and HSP90, respectively) in rat colonic mucosa was investigated by Western blot analysis and immunohistochemical study before and after hyperthermia. Following pretreatment with or without hyperthermia, the rats received intrarectal infusion of various doses of acetic acid. The colonic mucosal damage was evaluated by macroscopic and microscopic assessments 24 hr after the intrarectal infusion of acetic acid. Expression of HSPs was significantly increased by hyperthermia in rat colonic mucosa. Immunohistochemical study also showed the increments of HSPs in the colonic mucosal cells after hyperthermia. Acetic acid-induced colitis was dramatically prevented by pretreatment with hyperthermia when HSP72 and HSP90 were preinduced. On the other hand, induction of HSP60 did not correlate with mucosal protection. Our findings suggest that HSP72 and HSP90 may have cytoprotective function against acetic acid-induced mucosal damage. These results may be important for understanding the mechanism of "adaptive cytoprotection" mediated by HSPs.

Acetic Acid↗
PubMed1997

Differential induction of HSP60 and HSP72 by different stress situations in rats. Correlation with cerulein-induced pancreatitis.

We previously reported that water-immersion stress specifically induced the synthesis of a 60-kDa heat-shock protein (HSP60, chaperonin homolog) in pancreatic cells and preinduction of HSP60 completely prevented development of cerulein-induced pancreatitis in the rat in an HSP60 quantitatively dependent manner. In order to study the cytoprotective function of a 72-kDa heat-shock protein (HSP72, stress-inducible hsp70), the effect of specific preinduction of HSP72 by hyperthermia on cerulein-induced pancreatitis was investigated and compared with the effect of preinduction of HSP60 in this study. Expression of HSP60 and HSP72 in the pancreas was investigated by immunoblot before and after water immersion or hyperthermia. Following pretreatment with water-immersion stress or hyperthermia, the rats were injected with cerulein (40 micrograms/kg, intraperitoneally). The pancreas wet weight and serum amylase concentration were measured before and after cerulein injection. Hyperthermia (42.5 degrees C, 20 min) specifically induced HSP72 in the pancreas. The synthesis of HSP60 was specifically induced by water-immersion stress in the pancreas. Cerulein-induced pancreatitis was clearly prevented by specific preinduction of HSP60 by water-immersion stress. However, preinduction of HSP72 by hyperthermia had no preventive effect on cerulein-induced pancreatitis. Our findings suggest that HSP60 and HSP72 have distinct functions in the pancreas, and their induction mechanisms are also different in vivo. These results could be important for understanding the mechanism of "adaptive cytoprotection" in the pancreas mediated by heat-shock proteins.

Amylases↗
PubMed1997

Induction of a 72-kDa heat shock protein and cytoprotection against thioacetamide-induced liver injury in rats.

Heat shock proteins are ubiquitous intracellular proteins induced by various physiological stress-related events. A 72-kDa heat shock protein (HSP72) has been reported to be an endogenous cytoprotectant in variety of cells in vitro. In order to study the cytoprotective function of HSP72 in the liver, the effect of preinduction of HSP72 in rat liver by systemic hyperthermia on thioacetamide-induced hepatic injury was investigated in this study. Expression of HSP72 in the liver was investigated by immunoblot and densitometric analysis. Rats were injected with thioacetamide (100 mg/kg, subcutaneously) with or without preinduction of HSP72 by hyperthermia. Serum AST and ALT concentrations were measured before and after thioacetamide injection in both group. Histologic alteration of the liver was evaluated also. Systemic hyperthermia (42.5 degrees C, 20 min) significantly induced HSP72 in the liver. Thioacetamide-induced hepatic injury was clearly prevented by preinduction of HSP72 by hyperthermia. Prevention of hepatocyte damage was more clear in the area around central veins where HSP72 induction was apparent. Our findings might suggest that HSP72 has an important function in the liver with respect to cytoprotection. These results might be important for understanding the mechanism of "adaptive cytoprotection" in the liver mediated by the function of heat shock proteins as "molecular chaperons" as reported in vitro.

Alanine Transaminase↗
PubMed1997

Opposite effects of isoniazid and fasting on the expression of CYP2E1 protein and mRNA in house musk shrew (Suncus murinus).

The effects of isoniazid and fasting on hepatic CYP2E1 in the suncus were investigated. Aniline hydroxylation and N-nitrosodimethylamine demethylation, which are known to be catalyzed by CYP2E1, in liver microsomes were induced and suppressed by the treatment with isoniazid and the fasting, respectively. Immunoblot analysis indicated that CYP2E1 protein in liver microsomes from isoniazid-treated suncus was increased in contrast to the result with the fasting of the suncus. Northern blot analysis showed that the treatment of suncus with isoniazid increased the expression of CYP2E1 mRNA in livers although the fasting of the suncus significantly decreased CYP2E1 mRNA. These results suggest that the regulation of hepatic CYP2E1 in the suncus by treatment with isoniazid and fasting was different from that in rats.

Amino Acid Sequence↗
PubMed1997

Alterations of lactate (+lipid) concentration in brain tumors with in vivo hydrogen magnetic resonance spectroscopy during radiotherapy.

RATIONALE AND OBJECTIVES: The authors determine whether assessment of the relative lactate(+lipid) concentration ([r-Lac(+lip)]) obtained from hydrogen magnetic resonance (MR) spectroscopy is useful for predicting the outcome of radiotherapy on brain tumors. METHODS: Fifty-one hydrogen MR spectroscopic studies were performed in eight patients with primary or metastatic brain tumor before and during radiotherapy. The r-Lac(+lip) calculated as the ratio of lactate(+lipid) peak area to total water was compared before and during radiotherapy in each case. The change of tumor volume measured on magnetic resonance images also was compared. RESULTS: The r-Lac(+lip) substantially decreased in the radiosensitive cases (three lymphomas and one brain cancer) but did not decrease, even at the end of therapy, in the radioresistant cases (two brain cancers and two glioblastomas). CONCLUSION: Assessment of r-Lac(+lip) may adjunctively contribute to the early prediction of the radiotherapeutic effect on brain tumors.

Adult↗
PubMed1997

Disseminated intra-abdominal cystic lymphangiomatosis with severe intestinal bleeding. A case report.

We describe cystic lymphangiomatosis with intestinal bleeding developing multiple lymphangiomas in the small intestine, mesentery, mesocolon, omentum, retroperitoneum, and spleen. Small intestinal fluorography showed multiple polypoid lesions, mainly in the jejunum. Ultrasonography, computed tomography, and magnetic resonance imaging showed diffuse cystic tumors in the mesentery and spleen. Cystic lymphangiomatosis was proved by histologic findings of the biopsied specimen at laparotomy.

Abdominal Neoplasms↗
PubMed1997

Acquired resistance to the anti-proliferative effect of interleukin-1 and interleukin-6 is a recessive phenotype in A375 human melanoma cells.

The proliferation of human melanoma cell line A375-6 is inhibited by several cytokines, including interleukin-1 (IL-1) and interleukin-6 (IL-6). However, during a long period of culture, the cells progressively acquire resistance to IL-1 irrespective of functional IL-1 receptor expression. These cells constitutively produce IL-1alpha and IL-6, and also acquire resistance to IL-6. In order to investigate the mechanism of the acquired resistance to these cytokines, we performed somatic cell hybridization experiments. Parental cells for the construction of hybrid cells were rendered G418- or hygromycin B-resistant by transfection with expression vectors containing drug-resistant genes. Hybridization was conducted using IL-1-resistant subclones A375-R8 and R19 and an IL-1 highly sensitive clone C2-1, which was originally resistant but became sensitive to IL-1 upon transfection with a human type I IL-1 receptor (IL-1R) expression plasmid. Cells produced by hybridization of resistant cells and C2-1 cells appeared to be sensitive to IL-1 and IL-6. In contrast, production of IL-1 was augmented in the hybrid cells. These results suggest that resistance to IL-1 and IL-6 is a recessive phenotype, while production of IL-1 is dominant in melanoma cells.

Cell Division↗
PubMed1997

Small cell carcinoma arising from the outer urethral orifice: a case report examined by histologic, ultrastructural and immunohistochemical methods.

A case of small cell carcinoma arising in the outer urethral orifice is presented. The resected tumor showed a proliferation of small round or fusiform neoplastic cells in the submucosa. Tumor cells were arranged in sheets or a trabecular manner and possessed markedly hyperchromatic nuclei with a high N:C ratio, closely resembling small cell carcinoma of the lung. Characteristically, pagetoid intraepithelial spreading could be identified. However, there was no evidence of in situ transitional cell carcinoma and adeno- or squamous cell carcinoma components anywhere. Ultrastructurally, each tumor cell contained only a few membrane-bound cored granules measuring 60-100 nm, which were compatible with neurosecretory granules, and desmosome-like intercellular attachments, but lacked aggregated microfilaments. By immunohistochemical examination, tumor cells were positive for epithelial markers, such as cytokeratin and epithelial membrane antigen, and neuron specific enolase, but negative for any other neuro-endocrine markers. Extensive systemic examination failed to show the primary site to be other than the outer urethral orifice. These findings indicate that the current tumor is a small cell carcinoma with neuro-endocrine differentiation arising from the outer urethral orifice.

Aged↗