Search PubMed⌕ Search

Biomedical subjects

T Masuda

Publications and source records attributed to T Masuda.

At least 55 records · Page 3Linked to original sources
PubMed2002

A case of primary cutaneous CD30+ T-cell lymphoproliferative disorder with features of granulomatous slack skin disease.

We present a patient with primary CD30+ cutaneous T-cell lymphoma whose histological and clinical features overlapped with those of granulomatous slack skin disease (GSSD). A 26-year-old woman had infiltrative erythema on the abdominal wall and an incurable ulcerative lesion on the left knee. Her skin progressively became atrophic and pendulous, showing a hyperpigmented appearance over almost the whole body. Histopathologically, a dense lymphoid cell infiltrate accompanying numerous macrophages and multinucleated giant cells (MGC) extended into the subcutaneous tissue. Most lymphoid cells were small and positive for T-cell markers. Some relatively large atypical cells were scattered in the lesion, most of which (60%) were positive for CD30. T-cell receptor-beta gene rearrangement was confirmed in the abdominal lesion. MGC infiltrated more dominantly into a deeeper layer of the skin with the elastic fibres there almost completely disappearing. Immunoreactivity for CD30 of MGC was negative and overexpression of elastolytic metalloproteinases was observed. The association between primary cutaneous CD30+ lym- phoproliferative disorders and GSSD has not previously been reported. Overexpression of elastolytic metalloproteinases in MGC contributes to the disappearance of the elastic fibres and enhances the severity of the clinical course.

Adult↗
PubMed2001

Regression of human T-cell leukemia virus type I (HTLV-I)-associated lymphomas in a rat model: peptide-induced T-cell immunity.

BACKGROUND: Human T-cell leukemia virus type I (HTLV-I) is etiologically linked to adult T-cell leukemia (ATL). The disease has a high mortality rate and is resistant to chemotherapy; therefore, immunologic approaches to treatment could be of interest. We have previously shown that athymic rats inoculated with a syngeneic (i.e., with the same genetic background) HTLV-I-infected T-cell line (FPM1-V1AX) develop ATL-like disease and that the transfer of T cells from normal syngeneic rats immunized with FPM1-V1AX cells prevents disease development. In this study, we further characterized the host antitumor immunity to explore the possibility of peptide-based vaccination against the ATL-like disease. METHODS: Immune T cells from rats immunized with FPM1-V1AX cells were analyzed for their phenotypes and cytotoxic properties. The epitope recognized by the T cells was analyzed by fine mapping. To evaluate the antitumor effects of a peptide-based vaccine, normal rats were immunized with synthetic oligopeptides corresponding to the epitope, the T cells were transferred to athymic rats inoculated with HTLV-I infected cells, and tumor size was monitored. RESULTS: Both CD4+ and CD8+ T-cell populations from rats immunized with FPM1-V1AX cells inhibited the growth of FPM1-V1AX cell-induced lymphomas in vivo. Long-term culture of splenic T cells from the immunized rats repeatedly resulted in establishment of CD8+ HTLV-I-specific cytotoxic T lymphocyte (CTL) lines restricted to the rat major histocompatibility complex class I molecule, RT1.A(l). The cytotoxicity of these lines was directed against the HTLV-I regulatory protein Tax and, specifically, against the epitope, amino acids 180-188 (GAFLTNVPY). Adoptive transfer of the Tax 180-188-specific CTL line or freshly prepared T cells from rats vaccinated with the Tax 180-188 oligopeptide prevented the development of FPM1-V1AX-cell induced lymphomas in athymic rats in comparison with control groups (two rats in each group). CONCLUSIONS: This study indicated a potential therapeutic effect of peptide-based vaccination against HTLV-I-induced lymphoproliferative disease.

Amino Acids↗
PubMed2001

Novel synthetic approach to 19-nor-1alpha,25-dihydroxyvitamin D(3) and its derivatives by Suzuki-Miyaura coupling in solution and on solid support.

19-nor-1alpha,25-Dihydroxyvitamin D(3) was synthesized by the Suzuki-Miyaura coupling of the A-ring intermediate 3, which was efficiently prepared from readily available 5-(tert-butyldimethylsilyl)oxycyclohex-2-enone (5), with the boronate compound of the C,D-ring portion. The method could be applied to a solid-phase synthesis to prepare the des-C,D derivatives of 19-nor-1alpha,25-dihydroxyvitamin D(3). [reaction: see text]

Calcitriol↗
PubMed2001

Absence of Msh2 protein expression is associated with alteration in the FHIT locus and Fhit protein expression in colorectal carcinoma.

Frequent loss of Fhit expression has been reported in human gastrointestinal tract carcinomas; opinions remain divergent regarding Fhit expression in colorectal carcinoma (CRC) cases. Recent studies have suggested that Fhit inactivation can be a consequence of defects in mismatch repair proteins, particularly Msh2. Immunohistochemical analysis of Msh2 and Fhit protein expression in 62 CRC cases was performed. The same CRCs were examined for allelic loss at three loci within or near FHIT and for FHIT mRNA expression by reverse transcription-PCR amplification. Half of the 62 CRC cases were positive for Fhit protein. Fhit protein loss correlated significantly with the progression of carcinoma (P < 0.01) as well as lymph node metastasis (P < 0.05). Loss of Msh2 protein correlated significantly with loss of Fhit protein (P < 0.05) and FHIT locus alteration (P < 0.05). Loss of Fhit protein expression was observed in 50% of sporadic CRCs and was significantly more frequent in more advanced cancers. Interestingly, alteration of the fragile FHIT locus and loss of Fhit protein expression were significantly more frequent in sporadic CRCs lacking Msh2 protein, suggesting that this mismatch repair protein may be important in maintaining the integrity of the common fragile locus within the FHIT gene.

Acid Anhydride Hydrolases↗
PubMed2001

Two distinct isopentenyl diphosphate isomerases in cytosol and plastid are differentially induced by environmental stresses in tobacco.

Two distinct cDNA clones (IPI1 and IPI2) encoding IPI were isolated from Nicotiana tabacum. In situ expression of isopentenyl diphosphate isomerase-1 (IPI1)- and IPI2-green fluorescent protein fusion constructs revealed that IPI1 and IPI2 were localized in chloroplast and cytosol, respectively. The level of IPI1 mRNA was increased under high-salt and high-light stress conditions, while that of IPI2 mRNA was increased under high-salt and cold stress conditions. Both IPI transcripts were increased in an abscisic acid-independent manner. This is the first report of a cytosolic IPI. The results indicated that two distinct IPIs were differentially induced in response to stress.

Abscisic Acid↗
PubMed2001

Two types of MGDG synthase genes, found widely in both 16:3 and 18:3 plants, differentially mediate galactolipid syntheses in photosynthetic and nonphotosynthetic tissues in Arabidopsis thaliana.

In Arabidopsis, monogalactosyldiacylglycerol (MGDG) is synthesized by a multigenic family of MGDG synthases consisting of two types of enzymes differing in their N-terminal portion: type A (atMGD1) and type B (atMGD2 and atMGD3). The present paper compares type B isoforms with the enzymes of type A that are known to sit in the inner membrane of plastid envelope. The occurrence of types A and B in 16:3 and 18:3 plants shows that both types are not specialized isoforms for the prokaryotic and eukaryotic glycerolipid biosynthetic pathways. Type A atMGD1 gene is abundantly expressed in green tissues and along plant development and encodes the most active enzyme. Its mature polypeptide is immunodetected in the envelope of chloroplasts from Arabidopsis leaves after cleavage of its transit peptide. atMGD1 is therefore likely devoted to the massive production of MGDG required to expand the inner envelope membrane and build up the thylakoids network. Transient expression of green fluorescent protein fusions in Arabidopsis leaves and in vitro import experiments show that type B precursors are targeted to plastids, owing to a different mechanism. Noncanonical addressing peptides, whose processing could not be assessed, are involved in the targeting of type B precursors, possibly to the outer envelope membrane where they might contribute to membrane expansion. Expression of type B enzymes was higher in nongreen tissues, i.e., in inflorescence (atMGD2) and roots (atMGD3), where they conceivably influence the eukaryotic structure prominence in MGDG. In addition, their expression of type B enzymes is enhanced under phosphate deprivation.

Amino Acid Sequence↗
PubMed2001

Monitoring of methyl jasmonate-responsive genes in Arabidopsis by cDNA macroarray: self-activation of jasmonic acid biosynthesis and crosstalk with other phytohormone signaling pathways.

Jasmonates mediate various physiological events in plant cells such as defense responses, flowering, and senescence through intracellular and intercellular signaling pathways, and the expression of a large number of genes appears to be regulated by jasmonates. In order to obtain information on the regulatory network of jasmonate-responsive genes (JRGs) in Arabidopsis thaliana (Arabidopsis), we screened 2880 cDNA clones for jasmonate responsiveness by a cDNA macroarray procedure. Since many of the JRGs reported so far have been identified in leaf tissues, the cDNA clones used were chosen from a non-redundant EST library that was prepared from above-ground organs. Hybridization to the filters was achieved using alpha-33P-labeled single-strand DNAs synthesized from mRNAs obtained from methyl jasmonate (MeJA)-treated and untreated Arabidopsis seedlings. Data analysis identified 41 JRGs whose mRNA levels were changed by more than three fold in response to MeJA. This was confirmed by Northern blot analysis by using eight representatives. Among the 41 JRGs identified, 5 genes were JA biosynthesis genes and 3 genes were involved in other signaling pathways (ethylene, auxin, and salicylic acid). These results suggest the existence of a positive feedback regulatory system for JA biosynthesis and the possibility of crosstalk between JA signaling and other signaling pathways.

Acetates↗
PubMed2001

Two-stage spin-flop transitions in the S = 1/2 antiferromagnetic spin chain BaCu(2)Si(2)O(7).

Two-stage spin-flop transitions are observed in the quasi-one-dimensional antiferromagnet BaCu(2)Si(2)O(7). A magnetic field applied along the easy axis induces a spin-flop transition at 2.0 T followed by a second transition at 4.9 T. The magnetic susceptibility indicates the presence of Dzyaloshinskii-Moriya (DM) antisymmetric interactions between the intrachain neighboring spins. We discuss a possible mechanism whereby the geometrical competition between DM and interchain interactions, as discussed for the two-dimensional antiferromagnet La(2)CuO(4), causes the two-stage spin-flop transitions.

Journal Article↗
PubMed2001

Inhibition of RNA synthesis differentially affects in vitro melatonin release from the pineal organs of ayu (Plecoglossus altivelis) and rainbow trout (Oncorhynchus mykiss).

The effects of actinomycin D (RNA synthesis inhibitor) and cycloheximide (protein synthesis inhibitor) on melatonin release from the cultured pineal organ of two teleosts with or without the circadian regulation of melatonin production (ayu Plecoglossus altivelis and rainbow trout Oncorynchus mykiss, respectively) were investigated. Actinomycin D decreased melatonin release from the pineal organ during the dark phase but there was a significant difference between the two species (22.2% for ayu and 59.1% for trout as compared with the respective control). This difference might be due to whether the circadian regulation via gene transcription of melatonin synthesis exists or not. On the other hand, cycloheximide decreased melatonin release to approximately 1% in both species, indicating that the fish pineal organ requires de novo protein synthesis to maintain rhythmic melatonin release.

Animals↗
PubMed2001

Accumulation of plant galactolipid affects cell morphology of Escherichia coli.

Monogalactosyldiacylglycerol (MGDG) is a major constituent of thylakoid membrane in chloroplasts. Therefore, it is considered to have an important role in the maintenance of the complicated structure of the thylakoid membrane. We have succeeded in cloning the enzyme for MGDG synthesis and overexpressed it in Escherichia coli. In this study we analyzed the morphology of the E. coli harboring the gene. The fatty acid composition of its membrane lipids did not differ between the wild type and transformant, except for the appearance of MGDG. However, transformant cells appeared to be elongated. DAPI staining revealed the entire intracellular region of filamentous cells to be stained; therefore, the elongation of the cells is probably due to a defect in cell division. Atomic force microscopy revealed that the transformant had a smooth but scratched surface. It was concluded that the excessive accumulation of a non-bilayer lipid, MGDG, interfered with the translocation of proteins across the plasma membrane, including those for cell division.

Escherichia coli↗
PubMed2001

Thiolutin, an inhibitor of HUVEC adhesion to vitronectin, reduces paxillin in HUVECs and suppresses tumor cell-induced angiogenesis.

Recent studies have shown that integrin alpha v beta 3, a receptor for vitronectin, plays an important role in tumor-induced angiogenesis and tumor growth and that antagonists of alpha v beta 3 inhibit angiogenic processes including endothelial cell adhesion and migration. On the other hand, most inhibitors of integrin alpha v beta 3 are peptide antagonists that include the Arg-Gly-Asp (RGD) motif. We therefore reasoned that non-peptide inhibitors of endothelial cell adhesion to vitronectin might be useful for inhibition of tumor angiogenesis in vivo. We screened for low-molecular-weight natural products able to inhibit adhesion of human umbilical vein endothelial cells (HUVECs) to vitronectin, and pyrrothine group compounds including aureothricin, thioaurin and thiolutin were isolated from microbial culture broths. Of these compounds, thiolutin inhibited adhesion of HUVECs to vitronectin the most effectively (IC(50), 0.83 microM). In vivo experiments showed that thiolutin significantly suppressed angiogenesis induced by tumor cells (S-180), a pathological form of neovascularization, in a mouse dorsal air sac assay system. To explore the mechanism of inhibition of HUVEC adhesion to vitronectin by thiolutin, we examined the effect of this agent on intracellular cell adhesion signaling. We found that the amount of paxillin in HUVECs was significantly reduced by thiolutin treatment, while those of other focal adhesion proteins including vinculin and focal adhesion kinase (FAK) were not. Metabolic labeling experiments showed that thiolutin enhanced degradation of paxillin in HUVECs. Protease inhibitors (MG115 and E64-D) decreased the rate of degradation of the paxillin induced by thiolutin and partially restored thiolutin-induced inhibition of HUVEC adhesion to vitronectin. Based on these findings, we concluded that thiolutin, an inhibitor of HUVEC adhesion to vitronectin, reduces the paxillin level in HUVECs and suppresses tumor cell-induced angiogenesis in vivo.

Animals↗
PubMed2001

DNA polymerase epsilon is required for coordinated and efficient chromosomal DNA replication in Xenopus egg extracts.

DNA polymerase epsilon (Pol epsilon) is thought to be involved in DNA replication, repair, and cell-cycle checkpoint control in eukaryotic cells. Although the requirement of other replicative DNA polymerases, DNA polymerases alpha and delta (Pol alpha and delta), for chromosomal DNA replication has been well documented by genetic and biochemical studies, the precise role, if any, of Pol epsilon in chromosomal DNA replication is still obscure. Here we show, with the use of a cell-free replication system with Xenopus egg extracts, that Xenopus Pol epsilon is indeed required for chromosomal DNA replication. In Pol epsilon-depleted extracts, the elongation step of chromosomal DNA replication is markedly impaired, resulting in significant reduction of the overall DNA synthesis as well as accumulation of small replication intermediates. Moreover, despite the decreased DNA synthesis, excess amounts of Pol alpha are loaded onto the chromatin template in Pol epsilon-depleted extracts, indicative of the failure of proper assembly of DNA synthesis machinery at the fork. These findings strongly suggest that Pol epsilon, along with Pol alpha and Pol delta, is necessary for coordinated chromosomal DNA replication in eukaryotic cells.

Animals↗
PubMed2001

An outbreak of food poisoning due to egg yolk reaction-negative Staphylococcus aureus.

An outbreak of staphylococcal food poisoning due to an egg yolk (EY) reaction-negative strain occurred in Japan. Twenty-one of 53 dam construction workers who ate boxed lunches prepared at their company cafeteria became ill, and eight required hospital treatment. The outbreak showed a typical incubation time (1.5-4 h with a median time of 2.7 h) and symptoms (vomiting and diarrhea) of staphylococcal food poisoning. Staphylococcus aureus, which produces staphylococcal enterotoxin (SE) A, was isolated from four fecal specimens of eight patients tested. Scrambled egg in the boxed lunches contained 20-40 ng/g of SEA, and 3.0 x 10(9)/g of viable S. aureus cells that produced this toxin. All isolates from patients and the food were EY reaction-negative, coagulase type II, and showed the same restriction fragment length polymorphism (RFLP) pattern. We concluded that the outbreak was caused by scrambled egg contaminated with EY reaction-negative S. aureus. In Japan, outbreaks of staphylococcal food poisoning are mainly caused by EY reaction-positive S. aureus, and EY reaction-negative colonies grown on agar plates containing EY are usually not analyzed further for detection of S. aureus. The present outbreak suggested that EY reaction-negative isolates should be subjected to further analysis to detect the causative agents of staphylococcal food poisoning.

Disease Outbreaks↗
PubMed2001

Detection of Salmonella enteritidis in shell and liquid eggs using enrichment and plating.

Detection methods using various enrichment and plating media and immunoconcentration for Salmonella enteritidis in shell and liquid eggs were evaluated. For liquid egg samples naturally contaminated with S. enteritidis, pre-enrichment in 225 ml of buffered peptone water with cysteine followed by selective enrichment in 10 ml of tetrathionate broth was the superior, resulting in the detection of S. enteritidis in all samples on six of the seven types of selective agar substrate investigated. This enrichment procedure also enabled detection of S. enteritidis in most of artificially inoculated shell egg and pasteurized liquid egg samples.

Animals↗
PubMed2001

A novel plant ferritin subunit from soybean that is related to a mechanism in iron release.

Ferritin is a multimeric iron storage protein composed of 24 subunits. Ferritin purified from dried soybean seed resolves into two peptides of 26.5 and 28 kDa. To date, the 26.5-kDa subunit has been supposed to be generated from the 28-kDa subunit by cleavage of the N-terminal region. We performed amino acid sequence analysis of the 28-kDa subunit and found that it had a different sequence from the 26.5-kDa subunit, thus rendering it novel among known soybean ferritins. We cloned a cDNA encoding this novel subunit from 10-day-old seedlings, each of which contained developed bifoliates, an epicotyl and a terminal bud. The 26.5-kDa subunit was found to be identical to that identified previously lacking the C-terminal 16 residues that correspond to the E helix of mammalian ferritin. However, the corresponding region in the 28-kDa soybean ferritin subunit identified in this study was not susceptible to cleavage. We present evidence that the two different ferritin subunits in soybean dry seeds show differential sensitivity to protease digestions and that the novel, uncleaved 28-kDa ferritin subunit appears to stabilize the ferritin shell by co-existing with the cleaved 26.5-kDa subunit. These data demonstrate that soybean ferritin is composed of at least two different subunits, which have cooperative functional roles in soybean seeds.

Amino Acid Sequence↗
PubMed2001

Effects of a kappa agonist, spiradoline mesylate (U62,066E), on activation and vaginocervical-stimulation produced analgesia in rats.

Previous research has demonstrated increased pain threshold during copulation, gestation, and parturition in animals. In the laboratory, mechanostimulation of the vaginocervical region in many animals, as well as humans, can increase responsiveness to noxious but not to innocuous stimuli. This increased pain inhibition to vaginocervical stimulation, which mimics natural parturition, is mediated by spinal and supraspinal neuropeptides, including the opiates. The present research was designed to ascertain the possible effects of a kappa opioid agonist on vaginocervical-stimulated analgesia in rats. Initially, the novel kappa-selective agonist, spiradoline mesylate (U62,066E; 0, 0.1, 1.0, 10.0 mg/kg, i.p.), was injected intraperitoneally and general behavioral arousal in an open field apparatus was recorded. Results from this experiment indicate that stimulation with the kappa-selective drug caused significant decreases in behavioral activity at the high dose as compared to saline and the medium and low doses. Next, the effects of U62,066E (0, 0.1, 1.0, 10.0 mg/kg, i.p.) on the analgesia associated with vaginocervical stimulation were determined in a tail flick apparatus. The kappa drug significantly increased antinociceptive thresholds prior to and during vaginocervical stimulation at the 0.1 and 1.0 mg/kg doses. By contrast, the high dose (10.0 mg/kg) of U62,066E decreased vaginocervical stimulation-produced analgesia. Results are discussed in terms of the potential of nonaddictive kappa-selective opioid compounds being utilized in reproductive pain.

Analgesics↗