Biomedical subjects

T Kanai

Publications and source records attributed to T Kanai.

At least 109 records · Page 6Linked to original sources

PubMed1997

Effect of angiogenesis inhibitor TNP-470 on the progression of human gastric cancer xenotransplanted into nude mice.

The effect of an angiogenesis inhibitor, TNP-470, on primary tumor growth, liver metastasis and peritoneal dissemination of gastric cancer was investigated by means of an orthotopic xenotransplanted model of 2 human gastric cancers, MT-2 and MT-5. TNP-470 showed a significant inhibitory effect on the growth of primary tumors after orthotopic transplantation of both xenografts when given at a dose of 30 mg/kg on alternate days from day 7 after transplantation (early treatment). However, growth of the MT-2 primary tumor was not inhibited by administration from day 14 after transplantation (late treatment). Liver metastasis was prevented significantly by early treatment of TNP-470. In particular, early treatment of MT-2 completely inhibited the development of macroscopic foci in the liver and was significantly more effective than late treatment. Peritoneal dissemination also was inhibited. Thus, TNP-470 was revealed to have strong inhibitory activity not only on primary tumors and liver metastases but also against peritoneal dissemination. These results suggest that this agent may provide a new approach to the treatment of gastric cancer.

Adenocarcinoma↗

PubMed1997

Derepression of gene expression mediated by the 5' upstream region of the isocitrate lyase gene of Candida tropicalis is controlled by two distinct regulatory pathways in Saccharomyces cerevisiae.

The 5' upstream region of the gene encoding isocitrate lyase of Candida tropicalis (UPR-ICL) is functional as a promoter in Saccharomyces cerevisiae, and it is regulated by carbon source; the expression of the gene is repressed when cells are grown on glucose, while it increases to a higher level in acetate-grown cells. Therefore, we have investigated regions in UPR-ICL responsible for gene expression in glucose-grown and acetate-grown cells. In glucose-grown cells, a deletion of the region between -801 and -569 (region G1) significantly decreased gene expression compared with that observed with the complete UPR-ICL. The region from -421 to -379 (region G2) also repressed gene expression in glucose-grown cells. In acetate-grown cells, two regions were found to strongly enhance gene expression, one between -728 and -569 (region A1) and the other between -370 and -356 (region A2). Whereas region A2 contained a sequence motif similar to the carbon-source-responsive element (CSRE), which mediates regulation by carbon source of S. cerevisiae ICL1, region A1 did not show similarity to any reported cis-acting elements. Deletion mutants of UPR-ICL containing only one of these regions showed that each region could independently activate gene expression to a similar level when the cells were grown on acetate. The influences of null mutations in the MIG1, SNF1 and CAT8 genes on regulation of UPR-ICL-mediated gene expression were examined. Expression of the ICL gene with full-length UPR-ICL increased about tenfold in mig1 cells grown on glucose, while little difference was observed in acetate-grown cells. The effects of snf1 and cat8 mutations were different between region-A1-mediated and region-A2-mediated gene expression in acetate-grown cells. Region-A2-mediated expression decreased 95% and 86% in snf1 and cat8 cells, respectively, while region-A1-mediated expression decreased 72% in snf1 cells and was not affected by the cat8 mutation. This finding indicates that region-A1-mediated gene expression is regulated by a pathway independent of CAT8, which is necessary for derepression of CSRE-mediated gene expression in S. cerevisiae.

Base Sequence↗

PubMed1997

Analysis of carbon source-regulated gene expression by the upstream region of the Candida tropicalis malate synthase gene in Saccharomyces cerevisiae.

We investigated the regulation of expression of a gene encoding malate synthase (MS) of an n-alkane-utilizable yeast Candida tropicalis in the yeast Saccharomyces cerevisiae, where its expression is highly induced by acetate. By comparing levels of gene expression in cells grown on glucose, acetate, lactate, and oleic acid, we found that the increase in gene expression was due to a glucose repression-derepression mechanism. In order to obtain information concerning the regulation of the gene expression, a fusion gene which consists of the 5'-upstream region of MS-2 (UPR-MS-2) and the lacZ gene (encoding Escherichia coli beta-galactosidase), was introduced into S. cerevisiae, and beta-galactosidase activities were measured with cells grown on glucose or acetate. Deletion analysis of UPR-MS-2 revealed that the region between -777 and -448 (against the translation initiation codon) enhanced the level of gene expression in both glucose- and acetate-grown cells. In this region, sequences which resemble binding sites of Rap1p/Grf1p/Tufp, a global transcription activator, were found at seven locations and one was found for another pleiotropic activator Abf1p. The result also suggested the presence of multiple upstream repression sequences (URSs), which function specifically in glucose-grown cells, in the region between -368 and -126. In the repressing region, there were three tandem C(A/T)CTCCC sequences and also a putative binding site of Mig1p, a transcriptional repressor which mediates glucose repression of several other genes. When MIG1 gene of S. cerevisiae was disrupted, the expression of the UPR-MS-2-lacZ gene in glucose-grown cells increased approx. 10-fold. Furthermore, the effect of deletion of a putative Mig1p binding site was abolished in the MIG1-disrupted strain, suggesting Mig1p binds to this site and brings about glucose repression. When the SNF1 gene was disrupted, the high level gene expression observed in acetate-grown cells bearing UPR-MS-2 was abolished. This indicated that derepression of UPR-MS-2 -mediated gene expression was dependent on Snf1p, as is the case of genes encoding isocitrate lyase and gluconeogenic enzymes in S. cerevisiae.

Acetates↗

PubMed1997

Serum vitamin K level and bone mineral density in post-menopausal women.

OBJECTIVE: Vitamin K is known to influence bone metabolism by facilitating the synthesis of osteocalcin (BGP). The bone mineral density decreases drastically after menopause. We investigated the relationship of bone mineral density, vitamin K levels and other biological parameters of bone metabolism in post-menopausal women. METHODS: Serum levels of vitamin K, BGP and other markers of bone metabolism were measured in 71 post-menopausal women (19 with reduced bone mineral density and 52 with normal bone density), and 24 women with climacteric symptoms receiving hormone replacement therapy (HRT), (6 with reduced bone mineral density and 18 with normal density). RESULTS: In the first group, women with reduced bone mineral density showed lower levels of vitamin K1 and K2 than those with normal bone mineral density. In the other group, the level of BGP decreased but levels of vitamin K showed no increase during HRT. CONCLUSION: The present findings suggested that vitamin K was related to post-menopausal bone mineral loss.

Bone Density↗

PubMed1997

The serum factor from patients with ulcerative colitis that induces T cell proliferation in the mouse thymus is interleukin-7.

The disturbance of immune regulatory T cells is related to the pathogenesis of ulcerative colitis. Here we demonstrated and characterized the serum factor from ulcerative colitis patients that induced proliferation of intrathymic T cells. The factor isolated from the patient sera by a combination of gel filtration and anion-exchange chromatography induced proliferation of CD4+CD8- intrathymic T cells in the organ-cultured embryonic mouse thymus. Purification and amino acid sequence analysis of the serum factor demonstrated that the N-terminal 12 sequence was homologous to that of interleukin-7. SDS-PAGE and Western blot confirmed that purified serum factor was interleukin-7. Enzyme immunoassay demonstrated that the serum interleukin-7 concentration was significantly increased in the patients. PCR and Southern blot hybridization demonstrated that interleukin-7 mRNA expression was increased in the thymus tissues from patients but decreased in the colonic mucosa. Since interleukin-7 is a crucial cytokine for proliferation and differentiation of T cells in the thymus, the present study indicates that interleukin-7 may contribute to the disturbance of immune regulatory T cells in ulcerative colitis.

Amino Acid Sequence↗

PubMed1997

LET dependence of cell death and chromatin-break induction in normal human cells irradiated by neon-ion beams.

We investigated the LET dependence of cell death and chromatin-break induction in normal human embryo cells irradiated by accelerated neon-ion beams. Neon-ion beams were generated by the Riken Ring Cyclotron (RRC) at the Institute of Physical and Chemical Research, Japan. Chromatin breaks were measured by counting the number of chromatin fragments detected by the premature chromosome condensation (PCC) technique. The results indicated that cell death and the induction of remaining chromatin breaks showed a qualitatively similar LET dependence. The LET RBE curves for both cell death and the induction of remaining chromatin breaks had a broad peak in the LET range of 120-300 keV/microm and steeply downward trend up to 340 keV/microm. These results suggest that there is a good correlation between cell death and the induction of remaining chromatin breaks by neon-ion beams with different LET values.

Cell Death↗

PubMed1997

Recombinant thermostable cycloinulo-oligosaccharide fructanotransferase produced by Saccharomyces cerevisiae.

A truncated fragment of the cycloinulo-oligosaccharide fructanotransferase (CFTase) gene of Bacillus circulans MCI-2554 was fused to the prepro secretion sequence of the alpha-factor and expressed in Saccharomyces cerevisiae under the control of the 5' upstream region of the isocitrate lyase gene of Candida tropicalis (UPR-ICL). Efficiently secreted recombinant CFTase protein (yeast CFTase) was purified. Yeast CFTase consisted of three protein molecules, each of which had CFTase activity (yeast CFTase 1 [116 kDa], yeast CFTase 2 [117 kDa], and yeast CFTase 3 [116 kDa]). Yeast CFTase 2 was the major product of the expression system employed and was shown to be N glycosylated by endoglycosidase H treatment. Yeast CFTase 1 was N glycosylated but had a short truncation at its N terminus, while yeast CFTase 3 did not contain an N-glycosylated carbohydrate chain(s). Yeast CFTase 2 showed an optimum pH, an optimum temperature, and a pH stability similar to those of CFTase purified from B. circulans but exhibited a significant increase in thermostability. Production of yeast CFTase by the strain which had two copies of the CFTase gene integrated into its chromosomes reached 391 U per liter of culture at 120 h, which corresponded to 8.40 mg of protein per liter, by shake-flask cultivation.

Amino Acid Sequence↗

PubMed1997

p53 overexpression and proliferative activity do not correlate with lymph node metastasis in early gastric cancer.

We investigated p53 overexpression and the proliferative activity of the primary lesion as well as the clinicopathological features of 75 patients with gastric cancer invading the submucosa (sm cancer), of whom 14 (18.7%) had lymph node metastasis. Among the clinicopathologic features studied, only lymphatic invasion by the primary tumor was related to lymph node metastasis. There was no relationship between immunohistochemical staining for p53 protein or Ki-67 and lymph node metastasis. The p53-positive rate was 35.7 and 57.1% in patients with and without metastasis, respectively, while the mean Ki-67 labeling index was 38.9 and 38.1%, respectively. Our results suggest that p53 mutation or the proliferative activity of sm cancer do not influence lymph node metastasis, even though p53 mutation may enhance the proliferative activity and metastatic potential of advanced gastric cancer.

Adenocarcinoma↗

PubMed1997

Measurement of pancreatic blood flow to prevent pancreatic juice leakage after pancreas-preserving total gastrectomy for gastric cancer.

In patients with gastric cancer, distal pancreatectomy was frequently performed for complete removal of the lymph nodes along the splenic artery, but this procedure sometimes induced pancreatic juice leakage, subphrenic abscess, and postoperative diabetes. To avoid these complications, pancreas-preserving total gastrectomy (PP) was developed by Maruyama et al. [World J Surg 1995; 19:552-536], with which the spleen, splenic artery, and fatty connective tissue including lymph nodes could be removed completely without distal pancreatectomy. From 1988 to 1995, 36 patients underwent PP in our department. Although there were no operative deaths and no patient developed postoperative diabetes, pancreatic juice leakage was observed in 4 patients (11.1%). We assumed that ischemia of the distal pancreas may have caused this pancreatic juice leakage and investigated the relationship between pancreatic blood flow (PBF) and this complication in 12 recent patients. A significant negative correlation between PBF in the pancreatic tail and the peak amylase level (PAL) in the drain fluid was demonstrated. Two patients with PBF values of 4.5 and 5.2 ml/min/100 g tissue, respectively, and a PAL of more than 2 x 10(5) U/l developed pancreatic juice leakage, whereas the 10 patients without this complication had PBF values above 6 ml/min/100 g tissue and a PAL of less than 2 x 10(4) U/l. These results suggest that measurement of PBF may be useful to predict the leakage of pancreatic juice after PP and that distal pancreatectomy may be preferable when PBF is extremely low.

Adult↗

PubMed1997

Increased interleukin-1 and interleukin-1 receptor antagonist levels in cervical mucus in the ovulatory phase in comparison with the follicular phase.

Interleukin-1 (IL-1) receptor antagonist (IL-1ra) levels in the cervical mucus of women in the ovulatory phase are significantly higher than those in the follicular phase. IL-1 titers of women in the ovulatory phase are also significantly higher than those in the follicular phase. A positive correlation between IL-1ra and IL-1 levels in the cervical mucus was observed. Immunohistochemistry using an anti-IL-1ra monoclonal antibody revealed positive staining in the epithelial cells of the endocervix. These results suggest that IL-1ra from cervical epithelial cells protects the reproductive system from the toxicity of IL-1 produced in the endocervix.

Adult↗

PubMed1997

Irradiation of mixed beam and design of spread-out Bragg peak for heavy-ion radiotherapy.

Data on cellular inactivation resulting from mixed irradiation with charged-particle beams of different linear energy transfer (LET) are needed to design a spread-out Bragg peak (SOBP) for heavy-ion radiotherapy. The present study was designed to study the relationship between the physical (LET) and biological (cell killing) properties by using different monoenergetic beams of 3He, 4He and 12C ions (12 and 18.5 MeV/nucleon) and to attempt to apply the experimental data in the design of the SOBP (3 cm width) with a 135 MeV/nucleon carbon beam. Experimental studies of the physical and biological measurements using sequentially combined irradiation were carried out to establish a close relationship between LET and cell inactivation. The results indicated that the dose-cell survival relationship for the combined high- and low-LET beams could be described by a linear-quadratic (LQ) model, in which new coefficients alpha and beta for the combined irradiation were obtained in terms of dose-averaged alpha and square root of beta for the single irradiation with monoenergetic beams. Based on the relationship obtained, the actual SOBP designed for giving a uniform biological effect at 3 cm depth was tested with the 135 MeV/nucleon carbon beam. The results of measurements of both physical (LET) and biological (90% level of cell killing, etc.) properties clearly demonstrated that the SOBP successfully and satisfactorily retained its high dose localization and uniform depth distribution of the biological effect. Based on the application of these results, more useful refinement and development can be expected for the heavy-ion radiotherapy currently under way at the National Institute of Radiological Sciences, Japan.

Animals↗

PubMed1997

Response of mouse intestine after single and fractionated irradiation with accelerated carbon ions with a spread-out Bragg peak.

The responses of mouse intestine were examined after irradiation with accelerated carbon ions with a spread-out Bragg peak. The carbon-ion beam (135 MeV/nucleon), accelerated by the RIKEN ring cyclotron facility, was modulated to have a spread-out Bragg peak (SOBP) 3 cm wide. In the SOBP the biological dose (relative physical dose x RBE) was designed in earlier studies to be flat at the 10% survival level of Chinese hamster V79 cells. The numbers of surviving crypt clonogenic cells after single and fractionated irradiation with the carbon-ion beam were obtained by a microcolony assay method. The composite single-dose survival curves for the crypt clonogenic cells were calculated and fitted by a linear-quadratic (LQ) model. An analysis with the LQ model for crypt clonogenic cells showed that the alpha coefficient increased along with increasing LET, and that the beta coefficient was relatively constant, even for high-LET radiations. The biological dose distributions for the crypt clonogenic cells at the 10% survival level were flat in the SOBP. The isoeffective design of the SOBP for the 135 MeV/nucleon carbonion beam, based on biological data from a mammalian in vitro cell system, appears to be applicable to the response of murine intestinal tissue in vivo.

Animals↗

PubMed1997

[A study of gastroesophageal reflux by 24-hour esophageal pH monitoring in patients with bronchial asthma].

To evaluate the incidence of abnormal gastroesophageal reflux in patients with bronchial asthma and the influence of drug therapy on the gastroesophageal reflux, we investigated the gastroesophageal reflux patterns using an ambulatory 24-hour esophageal monitoring in 25 healthy volunteers and 58 asthmatics. All the patients were stable conditions at the time of the study. Bronchodilator therapy was continued, if necessary along with steroid inhalation and xanthines. Compared with healthy volunteers, the asthmatics had significantly greater esophageal acid exposure time, more frequent reflux episode, and longer single reflux time. About 70% of asthmatics had abnormal gastroesophageal reflux. Asthma medications were not associated with the incidence of abnormal gastroesophageal reflux. However, asthmatics receiving beta(2)-stimulants therapy (n = 27) had significantly greater esophageal reflux exposure time than those not receiving (n = 31). Our study suggested that most asthmatics have abnormal gastroesophageal reflux unrelated to asthma attack or asthma medications and that beta(2)-stimulants used in asthmatics may worsen gastroesophageal reflux.

Adult↗

PubMed1997

Massive uncomplicated vascular immune complex deposits in the kidney of a patient with systemic lupus erythematosus.

The case of a patient with systemic lupus erythematosus (SLE) is reported which was accompanied by renal dysfunction and massive vascular immune deposits in the kidney without active glomerular lesions. The renal biopsy showed arterioles and small arteries with circumferential periodic acid-Schiff (PAS) and Masson trichrome-positive homogenous material in the subendothelial area in the absence of thrombotic, necrotizing or inflammatory lesions. Immunofluorescence and electron microscopy examination demonstrated immune deposits in the vascular walls. Glomeruli showed only minor abnormalities with a trend to collapse. There was no improvement in renal dysfunction over a 4-year period until the patient's death, despite steroid therapy producing a decrease in disease activity. The autopsy showed similar vascular changes to those seen in the biopsy, however; glomeruli were either sclerotic or showed a trend to collapse. Massive uncomplicated vascular immune complex deposition without active glomerular lesions is rare. The present case indicates that this type of lupus vasculopathy may be a prognostic factor for the loss of renal function in SLE mediated by hemodynamic glomerular injury.

Aged↗

PubMed1997

Dependence of induction of interphase death of Chinese hamster ovary cells exposed to accelerated heavy ions on linear energy transfer.

Induction of interphase death was examined in Chinese hamster ovary cells exposed to accelerated heavy ions (carbon, neon, argon and iron) of various linear energy transfers (LETs) (10-2000 keV/microm). The fraction of cells that underwent interphase death was determined by observing individual cells with time-lapse photography (direct method) as well as by counting cells undergoing interphase death made visible by the addition of caffeine (indirect method). After exposure to X rays, interphase death increased linearly with dose above a threshold of about 10 Gy, whereas it increased at a higher rate without a threshold after exposure to high-LET heavy ions. The relative biological effectiveness (RBE) compared to X rays, as determined at the 50% level of induction, increased with LET, reached a maximum at an LET of approximately 230 keV/microm and then decreased with further increase in LET. The range of LET values corresponding to the maximum RBE appears to be narrower for interphase death than for reproductive death (120-230 keV/microm), as assayed using loss of colony-forming ability as a criterion. The inactivation cross section for interphase cell death reached a plateau of 5-10 microm2. This means that the probability for the induction of interphase death by traversal of a single heavy-ion track through the nucleus (size: about 130 microm2) is about 0.04-0.08.

Animals↗

PubMed1997

[A case report of Vp3 hepatocellular carcinoma responding to multidisciplinary treatment].

We report a 60-year-old man who had hepatocellular carcinoma with tumor thrombus in the main portal vein and left portal branch (VP3HCC). He was treated with transarterial chemo-embolization, surgical resection and intra-arterial infusion chemotherapy. He is now surviving without any sign of recurrence for 12 months after the initial therapy, even though the prognosis of VP3HCC is poor. This is a case in which the effect of multidisciplinary treatment was indicated.

Antibiotics, Antineoplastic↗

PubMed1996

IL-15 stimulates the expansion of AIDS virus-specific CTL.

It has been assumed that the maturation of pre-CTL to virus-specific effector CTL is dependent upon IL-2-mediated T cell triggering through the IL-2R. In view of its similarity to IL-2 in its effects on immune cells, we sought to determine whether IL-15 can induce the expansion of AIDS virus-specific pre-CTL to mature CTL. PBL of SIV(mac)-infected rhesus monkeys or HIV-1-infected humans have previously been shown to expand to effector CTL when cultivated with a predicted CTL epitope peptide and rIL-2. We now demonstrate that rIL-15 facilitates this expansion of effector CTL. In fact, rIL-15-driven expansion of virus-specific CTL occurs in the presence of IL-2-neutralizing or anti-IL-2R Abs, indicating that this cellular maturation can occur in an IL-2-independent fashion. These studies suggest a mechanism by which CTL may be capable of expanding in vivo in the absence of IL-2 and functional CD4+ T lymphocytes.

Amino Acid Sequence↗

PubMed1996

Efficacy of an angiogenesis inhibitor, TNP-470, in xenotransplanted human colorectal cancer with high metastatic potential.

BACKGROUND: The summation of gene mutations increases the metastatic potential of colorectal cancer. The genetic characterization and hepatic metastatic potential of five xenotransplanted human colon carcinoma strains were investigated. Furthermore, the therapeutic effect of the angiogenesis inhibitor, TNP-470, was evaluated. METHODS: The correlation between gene mutation and rate of hepatic metastases of five colon cancer strains transplanted orthotopically or subcutaneously was evaluated. The strain with the highest hepatic metastatic rate from orthotopical tumors, TK-4, was used in the experiment with TNP-470 treatment. Mice were given tumor transplants orthotopically or subcutaneously followed by 30 mg/kg of TNP-470 on alternate days from Day 10 or Day 21 after transplantation, respectively. RESULTS: The rate of hepatic metastases from orthotopically transplanted tumors of 5 strains was 38 to 79%. Interestingly, TK-4 with K-ras and p53 mutations and overexpression of p53 protein induced hepatic metastases from both orthotopical (79%) and subcutaneous tumors (44%). Although TNP-470 only significantly inhibited subcutaneous tumor growth, its antimetastatic effect was significantly demonstrated on the hepatic metastases of both orthotopical and subcutaneous tumors. CONCLUSION: p53 mutation is thought to enhance angiogenesis, favoring the growth of the hepatic metastases. TNP-470 proved the excellent antimetastatic effect of TK-4 on hepatic metastases. TK-4 has the highest metastatic potential and p53 mutation. An antiproliferative effect was observed on the rapidly growing primary tumors in which angiogenesis may be dominant.

Animals↗