Biomedical subjects

H Tsujimoto

Publications and source records attributed to H Tsujimoto.

At least 163 records · Page 9Linked to original sources

PubMed1996

Molecular cloning of bovine mb-1 cDNA.

Ig-alpha of the B-cell antigen receptor complex forms a heterodimeric structure with Ig-beta on the plasma membrane of B-lymphocytes and is apparently involved in signal transduction during the activation of B-cells. Bovine leukemia virus (BLV) is predominantly a B-cell tropic retrovirus, which induces persistent lymphocytosis and leukemia/lymphoma of B-cell lineage in cattle. To understand the mechanisms of proliferation and tumorigenesis of bovine B-cells that are associated with BLV infection, we investigated the B-cell antigen receptor complex, especially bovine mb-1 encoding the bovine Ig-alpha protein. We isolated a full-length bovine mb-1 cDNA clone encoding 223 amino acid residues. The deduced amino acid sequence of the bovine mb-1 showed extensive homology with those of human and murine mb-1. The cytoplasmic tail of the bovine mb-1 also contained a consensus motif (D/E-X7-D/E-X2-L/I-X7-Y-X2-L/I) that may interact with the SH2 domain of src-type kinase. Interestingly, a similar consensus sequence motif was found in the BLV gp30env, although the overall sequence similarity between bovine mb-1 and BLVgp30 was not significant. Furthermore, elevated levels of mb-1 transcript were detected in various bovine leukemia/lymphoma cell lines. These results indicated that the proliferation of B-cells associated with BLV-infection may be related to abnormal signal transduction through the B-cell antigen receptor complex.

Amino Acid Sequence↗

PubMed1996

Hexamethylene bisacetamide as a chemopreventive agent in hamster cheek pouch tumorigenesis.

The chemopreventive effect of oral and intraperitoneal (i.p.) administration of hexamethylene bisacetamide (HMBA) on 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced tumour formation in hamster cheek pouches was investigated. Male Syrian hamsters were treated by painting both cheek pouches with a 0.5% solution of DMBA twice weekly for 11 weeks. In addition to DMBA application, Group 1 hamsters were given 1% HMBA continuously in the drinking water and Group 2 hamsters received i.p. injection of HMBA at a dose of 500 mg/kg three times per week during the experiment. Group 3 animals received DMBA application alone. Thirteen weeks after the start of the experiment, the numbers of cheek pouch tumours and tumour volume were significantly decreased by oral but not i.p. administration of HMBA. Low levels of HMBA were detected in the plasma of the hamsters which were given 1% HMBA in drinking water. These results indicate that oral administration of HMBA can act as a chemopreventive agent against hamster cheek pouch tumorigenesis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1996

Pharmacological effects of 5-fluorouracil microspheres on peritoneal carcinomatosis in animals.

A new delivery formulation (5FU-MS) of 5-fluorouracil (5FU), 5FU incorporated in microspheres composed of poly(glycolide-co-lactide) matrix, has been developed for the treatment of peritoneal carcinomatosis, and is designed to slowly release the incorporated 5FU for 3 weeks. Intraperitoneal 5FU-MS distributed higher concentrations of 5FU to the intraperitoneal tissues, such as the omentum and the mesentery, for a longer period with lower blood plasma concentrations than did the aqueous 5FU solution in rats. In experiments using mice, the lethal toxicity, determined by the probit method, in 5FU-MS was reduced to less than half that in aqueous 5FU solution. We evaluated the therapeutic effects on peritoneal carcinomatosis induced by the intraperitoneal inoculation of B-16 PC melanoma cells. The therapeutic effects of 5FU-MS were enhanced when compared with both the equivalent doses and same toxicity doses of the aqueous 5FU solution.

Animals↗

PubMed1996

Overexpression of the mexC-mexD-oprJ efflux operon in nfxB-type multidrug-resistant strains of Pseudomonas aeruginosa.

OprJ, overproduced in nfxB multidrug-resistant strains of Pseudomonas aeruginosa, and OprK, overproduced in the multidrug-resistant strain K385, were demonstrated to be immunologically cross-reactive using an OprJ-specific monoclonal antibody. Treatment of the purified proteins with trypsin or chymotrypsin yielded virtually indistinguishable digestion patterns, and the N-terminal sequence of two trypsin fragments was identical for both proteins, indicating that OprJ and OprK share identity. The N-terminal amino acid sequences were used to facilitate cloning of the oprJ gene on a 5kbp Kpnl fragment and a 10 kbp BamHl fragment. Nucleotide sequencing of portions of these fragments revealed that oprJ was the terminal gene in a putative three-gene operon, mexC-mexD-oprJ. The predicted mexC-mexD-oprJ gene products exhibit homology to the MexA-MexB-OprM components of the multidrug-resistance efflux pump of P. aeruginosa (43-46% identity). Consistent with an implied role for mexC-mexD-oprJ in drug efflux, the mexC-mexD-oprJ-hyperexpressing strain K385 showed reduced accumulation of a variety of antibiotics as compared with its parent strain, and this drug 'exclusion' was abrogated by energy inhibitors. The mexC and oprJ products are putative lipoproteins of a molecular mass of 40,707 and 51,742 Da, respectively, while mexD was predicted to encode a protein of 111 936 Da. Sequencing upstream of mexC revealed the presence of the nfxB gene transcribed divergently from the efflux genes. Overproduction of OprJ and the attendant multiple-antibiotic resistance of strain K385 was shown to result from a point mutation in nfxB, resulting in a H87-->R change in the predicted NfxB polypeptide. OprJ overproduction and multidrug resistance in K385 was reversed by the cloned nfxB gene, suggesting that nfxB encodes a repressor of mexC-mexD-oprJ expression. Consistent with this, the cloned nfxB gene repressed synthesis of a mexC-lacZ fusion in Escherichia coli. nfxB also repressed expression of a nfxB-lacZ fusion, indicating that NfxB negatively regulates its own expression. These data indicate that the multidrug resistance of nfxB strains is due to overexpression of an efflux operon, mexC-mexD-oprJ, encoding components of a second efflux pump in P. aeruginosa.

Amino Acid Sequence↗

PubMed1996

Cisplatin microcrystals suspended in oil: pathological study of acute toxicity in mice.

The pathological changes brought about by the i.p. administration of a new dosage format, cisplatin microcrystals suspended in oil (CDDP-Oil), was examined in mice. CDDP-Oil decreased the absolute weight and the relative weight (organ weight/body weight) of the kidney, liver and spleen in the mice receiving the dosage form. However, the severity of the reduction of the organ weight in the CDDP-Oil administration groups was not different from that in the cisplatin aqueous solution (CDDP-Sol) administration groups. Histologically, severe degeneration and atrophy were recognized in the kidney, large intestine, small intestine, thymus, spleen, bone marrow and lymph nodes in the CDDP-Oil administration groups as well as CDDP-Sol administration groups. However, there were no additional changes in the macroscopic and microscopic findings in the CDDP-Oil groups. From these results, we concluded that this dosage form did not change the toxicity of cisplatin in terms of pathological effects.

Animals↗

PubMed1996

New formulation of 5-fluorouracil in microspheres reduces toxicity in mice.

A new dosage formulation of 5-fluorouracil incorporated in microspheres (5-FU-MS) was developed for the treatment of peritoneal carcinomatosis. We studied the acute toxicity and side effects of i.p. 5-FU-MS in mice. The 50% lethal dose value for 5-FU-MS was 535.4 mg/kg of 5-FU, which was 2.22 times that of the aqueous 5-FU solution. Deaths occurred 12-17 days after the administration of 5-FU-MS, but within 11 days after the administration of aqueous 5-FU. Thus, lethal toxicity appeared later with 5-FU-MS than with aqueous 5-FU. There were no differences in pathologic findings on autopsy between mice given the two dosage formulations.

Animals↗

PubMed1996

Reduced activity of anabolizing enzymes in 5-fluorouracil-resistant human stomach cancer cells.

The mechanism of resistance to 5-fluorourcil (5-FU) was studied with NUGC-3/5FU/L, a human stomach cancer cell line which had acquired resistance as a consequence of repeated 5-day exposures to stepwise-increasing concentrations of 5-FU in vitro. NUGC-3/5FU/L was 200-fold and over 16-fold resistant to 96-h and 1-h exposures to 5-FU, respectively. NUGC-3/5FU/L incorporated less 5-FU into RNA, indicating resistance to the RNA-directed action of 5-FU. On the other hand, NUGC-3/5/5FU/L also showed resistance to in situ thymidylate synthase (TS) inhibition by 5-FU. Polymerase chain reaction-single-strand conformation polymorphism analysis of TS cDNA and a FdUMP ligand binding assay showed that quantitative and qualitative alterations of TS are not responsible for this resistance. In contrast, the ability to metabolize 5-FU to its active metabolites, FUTP and FdUMP, was reduced in NUGC-3/5FU/L. We found that not only the activities of uridine phosphorylase/kinase and orotate phosphoribosyl-transferase (OPRT), but also the level of phosphoribosyl pyrophosphate, a cosubstrate for OPRT, were significantly lower in NUGC-3/5FU/L than in the parent NUGC-3. These results indicated that resistance to 5-FU in NUGC-3/5FU/L is due to reduced activities of 5-FU-anabolizing enzymes, but not to an alteration of TS. 2'-Deoxyinosine effectively enhanced TS inhibition by 5-FU in the resistant cells, thus markedly sensitizing them to 5-FU.

Antimetabolites, Antineoplastic↗

PubMed1996

Establishment and characterization of a new canine B-cell leukemia cell line.

A new cell line derived from a spontaneous canine leukemia was established and designated GL-1. The cells have been cultured in a floating fashion and passaged for over two years. They were round with rich cytoplasm containing many rough endoplasmic reticula and mitochondria. Peroxidase staining was negative. The nuclei of many cells were round, but segmented nuclei were seen frequently. The doubling time of the cells was 27.3 hr and they had 78 chromosomes. Surface marker analysis using monoclonal antibodies (MABs) and flowcytometry revealed that GL-1 possessed CD45 and surface IgG. However, the cells did not react with MABs detecting T-cell markers. These results indicate that GL-1 has a lymphocytic lineage and is derived from a B-cell leukemia.

Animals↗

PubMed1996

Elevation of serum G-CSF level in horses with transportation-induced fever.

Levels of granulocyte-colony stimulating factor (G-CSF) in the blood of horses were measured before and after a long-distance transportation to clarify the pathogenesis of transportation-induced fever. The serum G-CSF level was measured by its ability to stimulate growth in a mouse myeloblastic cell line, NFS-60. Of 26 horses transported for a long distance, 9 had fever more than 39.0 degrees C during or after transportation. After transportation, the serum G-CSF level significantly increased in horses with transportation-induced fever but not in those without fever, and the serum G-CSF level correlated positively with the peak body temperature and with an increase in peripheral white blood cell count. These data indicate that microbial infection, which is closely related to the elevation of the serum G-CSF levels, is the causative factor of transportation-induced fever.

Animals↗

PubMed1995

The anti-proliferative effect of proliferating cell nuclear antigen-specific antisense oligonucleotides on human gastric cancer cell lines.

The proliferating cell nuclear antigen (PCNA) is a nuclear protein that leads DNA synthesis by the DNA polymerase delta. As the PCNA gene is strongly expressed in invasive gastric cancer cells with high proliferative activity, PCNA is suspected of playing an important role in the proliferation and advancement of gastric cancer. Thus, the effects of antisense oligonucleotides specific for PCNA mRNA were examined in seven gastric cancer cell lines. It was found that treatment with antisense oligonucleotides at concentrations of 10-40 microM dose-dependently inhibited the growth of all cell lines; however, random sequence oligonucleotides did not modify the proliferation of any type of cells. These results indicate that PCNA is essential for cell proliferation in gastric cancer cells, and that the growth inhibitory effect results from the inhibition of PCNA gene expression. Therefore, PCNA-specific antisense oligonucleotides may be effective in the treatment of gastric cancer.

Base Sequence↗

PubMed1995

Inhibitory effect of tyrphostin on the replication of herpes simplex virus type 1.

Tyrphostins 9 and 47, inhibitors of protein-tyrosine kinase, inhibited the replication of herpes simplex virus type 1 (HSV-1), whereas tyrophostin 1, which does not inhibit protein-tyrosine kinase, did not affect the replication of HSV-1. The inhibitory effect of tyrphostin 9 was more potent than that of tyrphostin 47, and the IC50 of tyrphostin 9 was 40 nM. Sodium orthovanadate, an inhibitor of protein phosphotyrosine phosphatase, increased HSV-1 plaque formation and its effect was partly reversed by tyrphostin 9. The phosphorylation of viral phosphoproteins was decreased by tyrphostin 9 in a dose-dependent manner, but the tyrphostin 9-induced reduction of protein synthesis was not dose-dependent. At the late stage of infection, tyrosine phosphorylation was demonstrated in HSV-1 phosphoproteins. These results indicate that protein-tyrosine kinase is involved in the replication of HSV-1 and that tyrphostin can inhibit the synthesis and post-translational phosphorylation of the viral proteins.

Animals↗

PubMed1995

Chromosomal translocations in two feline T-cell lymphomas.

Two feline malignant lymphoma cell lines, FT-1 and FT-G, established from cats naturally infected with the feline leukemia virus were analyzed for chromosomal aberrations. Both FT-1 and FT-G cells had a modal number of 38 which is the normal diploid (2n) chromosome number of the domestic cat. G-banding-analysis showed that FT-1 had a translocation involving the short arms of chromosome A2 and D3--t (A2;D3) (p-;p+), and FT-G had a translocation involving the short arms of chromosomes A2 and B2--t (A2;B2) (p-;p+). Our data suggest that the chromosomal translocations were closely associated with the tumorigenesis in malignant lymphoma in cats.

Animals↗

PubMed1995

Molecular cloning of equine interleukin-1 alpha and -beta cDNAs.

Equine interleukin-1 alpha (IL-1 alpha) and IL-1 beta were molecularly cloned to establish a basis for research on inflammatory and immune responses in the horse. Equine peripheral blood mononuclear cells (PBMC) were stimulated with lipopolysaccharide (LPS), and cDNA clones of equine IL-1 alpha and IL-1 beta covering the whole coding sequences were isolated from them. These equine IL-1 alpha and IL-1 beta clones contained open reading frames encoding 271 and 269 amino acids, respectively. The deduced amino acid sequence of equine IL-1 alpha showed 71.6% and 60.2% similarity with that of human and murine IL-1 alpha, respectively. Similarly, the amino acid sequence of equine IL-1 beta showed 66.7% and 61.8% similarity with that of human and murine IL-1 beta, respectively. In both equine IL-1 alpha and IL-1 beta, amino acids at miristoylation sites were well conserved. Dot blot analysis indicated that the expression of IL-1 beta was predominant to that of IL-1 alpha in equine PBMC stimulated with LPS or phorbol myristate acetate.

Amino Acid Sequence↗

PubMed1995

Gammopathy with two M-components in a dog with IgA-type multiple myeloma.

A 12-year neutered male mixed-breed dog was referred to hospital for evaluation of chronic diarrhea. Cellulose acetate electrophoresis of its serum revealed two monoclonal peaks in the gamma-globulin fraction. On immunoelectrophoretic analysis, the two monoclonal peaks in the gamma-globulin region were strongly precipitated with anti-dog IgA serum. On sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis, the fractions corresponding to these two peaks were shown to be dimer and trimer or tetramer of immunoglobulin consisting of heavy and light chains. These results indicated that the studied dog had gammopathy with two M-components with dimer and trimer or tetramer of IgA. Accumulations of large amounts of these immunoglobulins with very high molecular weight in the serum were concluded to induce the hyperviscosity syndrome in this dog in the terminal stage.

Animals↗

PubMed1995

Effect of local administration of epidermal growth factor on 9,10-dimethyl-1,2-benzanthracene-induced tumour formation in hamster cheek pouch.

The effect of local administration of epidermal growth factor (EGF) on 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced tumour formation was investigated in a hamster cheek pouch carcinogenesis model. DMBA-treated hamsters underwent either sialoadenectomy (groups 1 and 2) or a sham operation (groups 3 and 4). Thereafter, EGF (groups 1 and 3) or vehicle (groups 2 and 4) was applied to the cheek pouches for 6 weeks. Fourteen weeks after the beginning of the experiment, the number of cheek pouch tumours was significantly greater in EGF-treated hamsters than in vehicle-treated hamsters, irrespective of whether the submandibular glands had been removed. The number of forestomach tumours, induced by DMBA application to the cheek pouches, was also increased by EGF. These results suggest that EGF applied from the luminal side of the mucosa stimulates tumour formation in the hamster cheek pouch and forestomach.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Site-specific implantation in the milky spots of malignant cells in peritoneal dissemination: immunohistochemical observation in mice inoculated intraperitoneally with bromodeoxyuridine-labelled cells.

To investigate the site-specific implantation of cancer cells in peritoneal dissemination, we inoculated CDF1 mice intraperitoneally with mouse P388 leukaemia cells labelled with bromodeoxyuridine (BrdU) and then observed immunohistochemically the distribution of the cells in the greater omentum taken from the mice using an anti-BrdU antibody. We found the BrdU-labelled cells infiltrating selectively into the milky spots in the omentum. Furthermore, we intraperitoneally inoculated the BrdU-labelled P388 cells at 10(5), 10(6) and 10(7) cells per mouse into three groups of ten CDF1 mice and then quantified the distribution of the BrdU-labelled cells by counting the number of the labelled cells per unit area at each milky spot and non-milky spot site in the omentum. Inoculations of 10(5), 10(6) and 10(7) BrdU-labelled P388 cells per mouse resulted in 15.8 +/- 13.3, 120 +/- 46.5 and 504 +/- 208 cells mm-2 respectively in the milky spot sites and 9.14 x 10(-3) +/- 1.58 x 10(-2), 1.14 x 10(-1) +/- 7.82 x 10(-2) and 7.07 x 10(-1) +/- 5.98 x 10(-1) cells mm-2 respectively in the non-milky spot sites. The ratios of the mean labelled cell numbers in the milky spot sites vs those in the non-milky spot sites were 1728:1, 1049:1 and 713:1 respectively. In all cases, there were statistically significant differences in the number of BrdU-labelled cells mm-2 between milky spot sites and non-milky spot sites. However, the ratios decreased as the numbers of inoculated cells increased. In addition, we inoculated C57/BL mice intraperitoneally with B-16 PC melanoma cells, which were easily differentiated from the other cells by the intrinsic black melanin, and examined the distribution of the cells macro- and microscopically. The B-16 PC melanoma cells were also found to be infiltrating preferentially into the milky spots in the omentum. These results suggest that cancer cells seeded intraperitoneally specifically infiltrate the milky spots in the early stages of peritoneal dissemination.

Animals↗

PubMed1995

Effects of jump training on bone hypertrophy in young and old rats.

The effects of jump training on bone hypertrophy were investigated in 3, 6, 12, 20 and 27 month-old female Fischer 344 rats. The rats of all age groups were divided into jump training (height: 40 cm, 100 times/day, 5 days/wk for 8 wk), run training (speed: 30 ml/min, 1 h/day, 5 days/wk for 8 wk) or sedentary group. Fat-free dry weights (FFW) of the femur and the tibia were significantly greater in the jump-trained rats than in the run-trained rats, and were significantly greater in the run-trained rats than in the sedentary rats. Jump training significantly increased FFW of the femur and the tibia not only in young rats but also in old rats, while run training did not increase FFW significantly in old rats. In young rats, both jump training and run training significantly increased the length of the femur and the tibia and the diameter of the femur. The diameter of the tibia was greater in the jump-trained rats than in the sedentary and the run-trained rats in all age groups. The results of the present study indicate that jump training was a more effective training mode than run training for bone hypertrophy and that the effects were not limited by age.

Adipose Tissue↗

PubMed1995

Therapeutic effects of the angiogenesis inhibitor TNP-470 against carcinomatous peritonitis in mice.

The therapeutic effects of the new anti-angiogenesis factor TNP-470 were examined against carcinomatous peritonitis in mice. In the first experiment using carcinomatous peritonitis caused by i.p. inoculation of 10(6) M5076 tumor cells, TNP-470 solution was injected i.p. in a bolus of 50 mg/kg body weight into two groups of 10 mice either 1 or 8 days after the i.p. inoculation. The administration of TNP-470 on day 1 extended the survival time of the mice compared with 10 control mice receiving no treatment, whereas TNP-470 given on day 8 did not affect the survival time. In the next experiment on the M5076 tumor, TNP-470 solutions at 100 or 300 mg/kg were injected i.p. in a bolus into two groups of 20 mice 1 day after the inoculation 10(6) tumor cells, respectively. The administration of TNP-470 at 100 mg/kg also had an inhibitory effect. However, TNP-470 at 300 mg/kg caused toxic death in half of the mice. Next, we examined the effects of TNP-470 on another type of carcinomatous peritonitis model, which was caused by i.p. inoculation of 10(6) B16 melanoma cells. In this experiment, TNP-470 solutions in a bolus of 150 mg/kg were injected i.p. into six groups of 10 mice each on day 1 only (group 1), on days 1 and 4 (group 2), on days 1, 4 and 7 (group 3), on day 8 only (group 4), on days 8 and 11 (group 5), or on days 8, 11 and 14 (group 6), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗