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Biomedical subjects

T Imai

Publications and source records attributed to T Imai.

At least 307 records · Page 17Linked to original sources
PubMed1998

Gene gun-mediated in vivo analysis of tissue-specific repression of gene transcription driven by the chicken ovalbumin promoter in the liver and oviduct of laying hens.

In order to search tissue-specific elements in the 5'-upstream promoter region, gene gun was used to transfect in vivo plasmid DNAs with varying lengths of truncated ovalbumin promoter fused to the CAT reporter gene to the oviduct and liver of laying hens. The results indicated that in the oviduct, consistently high reporter gene expression was observed irrespective of the length of the truncated ovalbumin gene promoters, whereas in the liver the ovalbumin promoter extending from -3200 to +8 bp suppressed substantially the reporter gene expression compared with consistently high gene expression obtained by the ovalbumin promoters from -2800 to +8 bp or shorter length. It was concluded, therefore, that a tissue-specific silencer-like element might reside most likely in the ovalbumin gene promoter region between -3200 and -2800 bp which represses the ovalbumin gene transcription in the liver, but not in the oviduct of laying hens.

5' Untranslated Regions↗
PubMed1998

EBI1-ligand chemokine (ELC) attracts a broad spectrum of lymphocytes: activated T cells strongly up-regulate CCR7 and efficiently migrate toward ELC.

EBI1-ligand chemokine (ELC) is a CC chemokine constitutively expressed in various lymphoid tissues and a high-affinity functional ligand for EBI1/CCR7, a seven transmembrane G-protein-coupled receptor originally identified as an Epstein-Barr virus (EBV)-inducible gene. Here we examined chemotactic activity of ELC on peripheral blood leukocytes. ELC attracted both CD4+ and CD8+ T cells, particularly efficiently after activation with IL-2 or with phytohemagglutinin (PHA) plus IL-2, as well as CD19+ B cells, but not CD16+ NK cells, CD14+ monocytes or neutrophils. Among CD3+ T cells, ELC attracted both CD45RO- naive and CD45RO+ memory subsets. ELC also induced vigorous calcium mobilization in T cells stimulated with IL-2 with an ED50 of 3 nM. ELC fused with the secreted form of alkaline phosphatase (ELC-SEAP) specifically bound to lymphocytes and this binding was blocked only by ELC among 10 CC chemokines so far tested. Notably, lymphocytes stimulated with IL-2 or T cells expanded by PHA plus IL-2 showed much higher levels of binding than fresh lymphocytes. Consistently, CCR7 mRNA was detected in CD4+ and CD8+ T cells as well as B cells, but not in NK cells, monocytes or neutrophils, and was dramatically increased in T cells upon treatment with IL-2 or with PHA plus IL-2. Like ELC mRNA, CCR7 mRNA was expressed in various lymphoid tissues. By in situ hybridization, ELC and CCR7 mRNA were detected in the parafollicular and inner cortical regions of a lymph node, and in the parafollicular regions of an appendix. Collectively, ELC and CCR7 may be involved in the trafficking of a broad spectrum of lymphocytes, especially activated T cells, into and within various lymphoid tissues.

Adult↗
PubMed1998

Developmental profiles of phosphorylated and unphosphorylated CREBs in murine calvarial MC3T3-E1 cells.

The cAMP-responsive element (CRE) binding protein/activating transcription factor (CREB/ATF) family plays a major role in the expression of skeletal-specific genes and skeletal tissue development. We analyzed the changes of the amount, degree of phosphorylation and binding activity of the CREB/ATF family in the course of development of the murine calvarial osteoblastic cell line MC3T3-E1 as an in vitro model system of bone formation. The amount of CREB in the whole-cell extract detectable by Western blot analysis was high through all stages of development and maximal in the proliferation stage. The degree of phosphorylation estimated with anti-phosphorylated CREB antibody changed greatly and reached high levels in the proliferation stage and early mineralization stage. The ratio of phosphorylated CREB to total CREB in the CREB-CRE complex was also examined by gel shift assay. Although the binding to the consensus/CRE probe reached almost equally high levels in the proliferation stage and early mineralization stage, the relative level of phosphorylated CREB in the CREB-CRE complex was different in these two stages. In the early mineralization stage, most CREB bound to consensus/CRE was phosphorylated, while both phosphorylated and unphosphorylated CREB were bound to consensus/CRE in the proliferation stage. ATF-1 was also detected as a minor component bound to the consensus/CRE probe. The alteration of the binding of CREB to consensus/CRE over the course of osteoblast development supports the hypothesis that CREB may regulate the expression of genes defining the developmental sequence of MC3T3-E1 cells.

Alkaline Phosphatase↗
PubMed1998

L-galactono-gamma-lactone dehydrogenase from sweet potato: purification and cDNA sequence analysis.

L-Galactono-gamma-lactone dehydrogenase (EC 1.3.2.3, GLDHase) was partially purified from mitochondria of sweet potato tuberous roots over 600-fold on a specific activity basis, followed by purification of the enzyme protein of 56 kDa by a preparative SDS-PAGE. The absorption spectrum of the hydroxylapatite column-purified GLDH-ase showed peaks at 448 and 373 nm, suggesting the presence of flavin as a prosthetic group. The activity of GLDH-ase was inhibited by lycorine, an alkaloid which inhibits ascorbic acid biosynthesis in vivo. N-terminal partial sequences of four internal polypeptides generated by partial digestion of GLDHase with V8 protease were determined. The deduced nucleotide sequences were used to amplify a cDNA fragment of the GLDHase gene. The clone encoded a polypeptide of 581 amino acid residues with a molecular mass of 66 kDa. The deduced amino acid sequence showed 77% identity with that of cauliflower GLDHase, and significant homology to those of L-gulono-gamma-lactone oxidase (22% identity) from rat and L-galactono-gamma-lactone oxidase from yeast (17% identity), which are enzymes involved in L-ascorbic acid biosynthesis in these organisms. The absorption spectrum and cDNA sequence suggested that the flavin group bound noncovalently. We conclude that GLDHase, L-gulono-gamma-lactone oxidase and L-galactono-gamma-lactone oxidase are homologous in spite of the difference in substrates and electron acceptors. Genomic Southern analysis suggested that GLDHase gene exists as a single copy in the genome of sweet potato.

Amaryllidaceae Alkaloids↗
PubMed1998

Matrix-producing carcinoma of the breast: case report with radiographical and cytopathological features.

A case of matrix-producing carcinoma (MPC), which is a unique variant of breast cancer, is described with cytopathological and radiographical findings. A 75-year-old female presented with a palpable mass in her right breast. After confirmation of the cytopathological diagnosis, the patient received a right mastectomy with ipsilateral axillary lymph node dissection. The histopathological examination revealed MPC. The Union Internationalis Contra Cancrum postoperative clinical stage was IIB. The patient is well and without disease 18 months after the surgery.

Aged↗
PubMed1998

Adoptive immunotherapy of patients with metastatic renal cell cancer using lymphokine-activated killer cells, interleukin-2 and cyclophosphamide: long-term results.

BACKGROUND: Initial results of adoptive immunotherapy using lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2) appeared to offer promise for treating renal cell cancer (RCC). However, lower response rates were seen in subsequent trials, and the long-term results of this treatment method have not been fully reported. In this study, we examine long-term results of adoptive immunotherapy using LAK cells, IL-2, and cyclophosphamide (LAK/IL-2/CPM therapy). METHODS: We administered 10 courses of therapy to 9 patients with advanced RCC. One patient had liver and para-aortic lymph node metastases; the others had only lung metastases. The clinical effects were initially evaluated 4 weeks after therapy and follow-up was continued for periods of 43 to 76 months. RESULTS: The 4-week evaluation revealed 3 complete responses (CR), 3 partial responses (PR), 1 minor response (MR), 1 patient with no change in disease status (NC), and 2 patients whose disease progressed (PD). One CR patient remained apparently free of disease for 43 months. After tumors recurred in the lung of another CR patient further disease progression was suppressed by IL-2 administration until the patient died from other causes at 46 months. The third CR patient showed tumor recurrence in the lung and was re-treated with the same LAK/CPM/IL-2 therapy. Lung tumors decreased in size (PR), but the patient died due to brain metastasis 2 months after the second round of treatment. The 2 initial PR patients, as well as the MR and NC patients, developed regrowth or new metastatic lesions within 2 to 15 months following therapy. The 2 PD patients died 2 and 9 months after therapy. CONCLUSION: Long-term effects of LAK/IL-2/CPM therapy were not correlated with the maximal response observed 4 weeks after therapy. Although LAK/IL-2/CPM therapy appears suitable for use as induction therapy in RCC, our data suggest that long-term suppression will require surgical removal of remnant tumors or more intensive maintenance therapy.

Adult↗
PubMed1998

Cytotoxicity of absorption enhancers in Caco-2 cell monolayers.

This study was performed to evaluate the utility of absorption enhancers with reference to mucosal cell cytotoxicity. Overall assessment of the damage to plasma, lysosomal and nuclear membranes by three absorption enhancers, sodium deoxycholate, sodium caprate and dipotassium glycyrrhizinate, was performed on Caco-2 cell monolayers. The cytotoxicities of sodium deoxycholate (0.02-0.1% w/v), sodium caprate (0.1-0.5% w/v) and dipotassium glycyrrhizinate (0.5-2% w/v) were evaluated by the trypan blue-exclusion test, the protein-release test, the neutral-red assay, the DNA--propidium iodide staining test and the test for recovery of transepithelial electrical resistance (TEER) up to 24 h after treatment with each enhancer. Sodium dodecyl sulphate (SDS; 0.1% w/v), a potent surfactant, was used as positive control. SDS at this level was significantly cytotoxic whereas dipotassium glycyrrhizinate was not cytotoxic in any tests. Results from the trypan blue-exclusion and protein-release tests showed that high concentrations of sodium caprate (0.5% w/v) and sodium deoxycholate (0.1% w/v) were significantly cytotoxic to the plasma membrane. The neutral-red assay, an indicator of damage to lysosomal membranes, revealed that 0.5% (w/v) sodium caprate had no effect whereas the uptake of neutral red was slightly increased by treatment with 0.1% (w/v) sodium deoxycholate, implying that the compound had cell-growth-enhancing activity. Nuclear-membrane damage, as evaluated by the DNA--propidium iodide staining test, was severe in cell monolayers treated with 0.5% (w/v) sodium caprate compared with that induced by 0.1% (w/v) sodium deoxycholate. In the TEER recovery test, TEER failed to recover 24 h after treatment with 0.5% (w/v) sodium caprate and 0.1% (w/v) SDS, but recovered after treatment with 0.1% (w/v) sodium deoxycholate. The recovery of TEER might be related to nuclear membrane damage and cell-growth-enhancing activity. These results indicate that of the three classes of enhancer, dipotassium glycyrrhizinate was not cytotoxic and that high concentrations of sodium caprate and sodium deoxycholate could damage plasma and nuclear membranes.

Caco-2 Cells↗
PubMed1998

Genetic analysis of Histoplasma capsulatum strains isolated from clinical specimens in thailand by a PCR-based random amplified polymorphic DNA method.

Thirteen strains of Histoplasma capsulatum were isolated from clinical specimens, including those from AIDS patients, in Thailand. Random amplified polymorphic DNA (RAPD) analysis with three different PCR primers showed that the DNA fingerprint patterns of the Thai isolates were very similar to each other and homogeneous, with only one exceptional strain, although the patterns were clearly different from those of a reference North American strain with all primers tested. Although the difference in the DNA fingerprinting patterns was minor, Thai isolates could be classified into two to four groups. A common PCR band (about 700 bp) in the patterns of all H. capsulatum strains was extracted, and its DNA sequence was determined. A new PCR primer set for the identification of H. capsulatum species was developed based on this sequence information. This primer set was 100% successful in the identification of the reference strain as well as all Thai isolates. The results of specificity tests of the primer set for the identification of the fungus are also discussed.

AIDS-Related Opportunistic Infections↗
PubMed1998

Clinical similarities of hereditary progressive/dopa responsive dystonia caused by different types of mutations in the GTP cyclohydrolase I gene.

OBJECTIVE: Hereditary progressive dystonia with pronounced diurnal fluctuation [(HPD)/dopa responsive dystonia (DRD)] is a childhood onset dystonia which responds to levodopa. Various clinical signs and symptoms of HPD/DRD have been recognised to date. Mutations in the GTP cyclohydrolase I (GTP-CH-I) gene were recently identified as the cause of HPD/ DRD. In the present study, the GTP-CH-I gene and the clinical features of eight HPD/DRD patients from six families were analysed to determine the correlations between clinical expression and the mutations in the GTP-CH-I gene. METHODS: The exons, exon-intron junctions, and an indispensable part of the 5' flanking region of the GTP-CH-I gene were sequenced in the eight clinically diagnosed patients with HPD/DRD and their asymptomatic parents. RESULTS: Three independent mutations in the GTP-CH-I gene were found in three patients. One of the patients and her asymptomatic mother were heterozygous for a novel mutation at the initiation codon. The three patients with dissimilar GTP-CH-I mutations exhibited similar clinical features. The other five patients with normal sequences presented several features not manifested by the three patients with the mutations. No mutation was found in the 5' flanking region of any patients or their parents. CONCLUSIONS: A novel initiation codon mutation was found in a Japanese patient with HPD/DRD. The clinical manifestations common to the patients with HPD/ DRD with a mutated GTP-CH-I gene were also identified. Although focal manifestations of HPD/DRD associated with the mutations of this gene will be broadened, it is inferred that these clinical features are fundamental to HPD/DRD caused by mutations in this gene.

Adolescent↗
PubMed1998

Treatment of bilateral renal cell cancer and multiple lung metastasis: nephron-sparing surgery and resection of lung tumors after interleukin-2 therapy.

We report a case of bilateral renal cell cancer and multiple lung metastasis who was first treated with left radical nephrectomy and nephron-sparing surgery of the right kidney. Consecutive interleukin-2 administration achieved partial response in lung disease and residual tumors were surgically removed. The disease-free state has continued for 33 months.

Aged↗
PubMed1998

Secretion of adrenomedullin by renal tubular cell lines.

Adrenomedullin (AM) is a novel and potent vasodilator peptide originally isolated from human pheochromocytoma. The present study was designed to study whether AM is produced by and secreted from renal tubular cell lines and whether arginine vasopressin (AVP) affects AM secretion from these cell lines. Three renal tubular cell lines derived from different species (LLCPK1, MDCK, and MDBK) secrete AM-like immunoreactivity (AM-LI) into culture medium, the immunological and physicochemical properties of which are similar to that of synthetic human AM as evaluated by reverse-phase high-performance liquid chromatography. Among the three cell lines, AVP in combination with a phosphodiesterase inhibitor (isobutylmethylxanthine) stimulated AM-LI secretion most potently from MDCK cells in a time- and dose-dependent manner. In MDCK cells, a V2 receptor agonist (deamino-D-Arg8-vasopressin) dose-dependently stimulated AM-LI secretion in the same manner as AVP. Furthermore, the AVP-induced AM-LI secretion was blocked by a V2 receptor antagonist (OPC31260), but not by a V1 receptor antagonist (OPC21268). These data indicate that AM is secreted from renal tubular cell lines and that AVP stimulates AM secretion via V2 receptors, suggesting its autocrine/paracrine role in renal function.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Activation of transcriptionally active nuclear factor-kappaB by tumor necrosis factor-alpha and its inhibition by antioxidants in rat thyroid FRTL-5 cells.

ABSTRACT Tumor necrosis factor-alpha (TNF-alpha) exerts pleiotropic effects on thyroid follicular cells. However, the intracellular signaling pathway for the TNF-alpha action has not been well elucidated. The present study examined the effects of TNF-alpha on the activation of nuclear factor-kappa B (NF-kappaB) and on the expression of interleukin (IL)-6 gene in rat thyroid FRTL-5 cells. The treatment of the cells with TNF-alpha resulted in the nuclear translocation of p65-p50 heterodimer as well as p50-p50 homodimer NF-kappaBs. The treatment with the antioxidants 20 mM N-acetyl-L-cysteine (NAC) and 10 microM pyrrolidine dithiocarbamate (PDTC) inhibited the TNF-alpha-dependent activation of p65-p50 heterodimer but not the p50-p50 homodimer, indicating that generation of oxidants is required for the activation of the heterodimer NF-kappaB. When the plasmid containing the multimerized NF-kappaB sites upstream of a luciferase reporter gene was transfected into FRTL-5 cells, the treatment with NAC or PDTC prevented the TNF-alpha-dependent increase in the luciferase activities, indicating that the p65-p50 heterodimer is a transcriptionally active NF-kappaB. Accordingly, the TNF-alpha-dependent increase in IL-6 messenger RNA and in secretion of the protein was prevented by the treatment with NAC. These results strongly suggest that TNF-alpha increases the IL-6 gene expression through the activation of NF-kappaB in the thyroid cells, and that antioxidants suppress the TNF-alpha-dependent IL-6 expression by inhibiting the activation of the transcriptionally active NF-kappaB.

Animals↗
PubMed1998

Decreased type IV collagen of skin and serum in patients with amyotrophic lateral sclerosis.

OBJECTIVE: To study type IV collagen of skin and serum in patients with ALS. BACKGROUND: Collagen abnormalities of skin have been reported in ALS patients. However, little is known concerning type IV collagen in ALS. METHODS: We studied type IV collagen immunoreactivity of skin and measured serum levels of the 7S fragment of the N-terminal domain of type IV collagen (7S collagen) in patients with ALS and control subjects. RESULTS: The basement membrane as well as blood vessels of skin in ALS patients was weakly positive for type IV collagen as compared with those of diseased control subjects. This weak immunostaining became more pronounced as ALS progressed. The optical density for type IV collagen immunoreactivity in ALS patients was significantly lower (p < 0.001) than in diseased control subjects and was significantly decreased with duration of illness (r = -0.85, p < 0.01). Serum 7S collagen levels in patients with ALS were significantly decreased (p < 0.01) as compared with those in diseased and healthy control subjects and were negatively and significantly associated with duration of illness (r = -0.81, p < 0.001). There was an appreciable positive correlation between concentrations of serum 7S collagen and the density for type IV collagen immunoreactivity in ALS patients (r = 0.81, p < 0.02). CONCLUSIONS: These data suggest that a metabolic alteration of type IV collagen may take place in the skin of ALS patients and that the decreased levels of serum 7S collagen may reflect a decreased type IV collagen immunoreactivity of skin in patients with ALS.

Aged↗
PubMed1998

Alterations of skin glycosaminoglycans in patients with ALS.

BACKGROUND AND OBJECTIVE: Collagen abnormalities of skin have been reported among patients with ALS. However, little is known concerning glycosaminoglycans of the skin in ALS. Our objective was to clarify morphologic and biochemical findings of skin glycosaminoglycans among patients with ALS. METHODS: We performed morphologic studies and biochemical analysis of glycosaminoglycans of skin from 8 patients with ALS, 6 patients with other neurologic or muscular diseases (control group A), and 7 patients without neurologic disorders (control group B). RESULTS: The wide spaces that separate collagen bundles reacted strongly with Alcian blue stain in skin from patients with ALS and stained more markedly as ALS progressed. Staining with Alcian blue was virtually eliminated by Streptomyces hyaluronidase. The content of hyaluronic acid was significantly higher (p < 0.001) among patients with ALS than in control groups A and B. There was a significant positive correlation between content of hyaluronic acid and duration of illness among patients with ALS (r = 0.88, p < 0.01). However, there was no significant difference in content of dermatan sulfate, chondroitin sulfate-4S, or chondroitin sulfate-6S between patients with ALS and control groups A and B. There was also an appreciable positive correlation between optical density of Alcian blue and content of hyaluronic acid among patients with ALS (r = 0.92, p < 0.01). CONCLUSIONS: The data suggest that a metabolic alteration of glycosaminoglycans related to the increased amount of hyaluronic acid may take place in the skin of patients with ALS.

Aged↗
PubMed1998

Abnormal FSH hypersecretion as an endocrinological manifestation of POEMS syndrome.

Two patients with POEMS syndrome had high basal levels of FSH in the absence of primary hypogonadism. They were fertile eugonadal men with normal serum testosterone and estradiol levels. Provocation with LH-releasing hormone revealed blunted response of FSH secretion, but normal response of LH secretion in both patients, and one had pituitary microadenoma on brain MRI. This report adds primary FSH hypersecretion in the absence of primary testicular failure to the list of endocrinopathy of POEMS syndrome.

Adenoma↗
PubMed1998

Casein hydrolysate as a rapid and/or enteric dissolving additive for oral drugs.

Two types of casein hydrolysates, casein A (mean peptide length 3.3) and casein B (mean peptide length 17.4) were prepared by the enzymatic hydrolysis of casein, and their effects on in vitro dissolution rates and oral bioavailability of drugs were evaluated. The in vitro dissolution behavior of the kneaded mixture of three drugs (diclofenac acid, diazepam, and prednisolone) with caseins A and B were significantly improved compared to the drugs alone, even at 1:1 weight ratio of drug and casein hydrolysate, even though casein A and casein B did not interact with drug molecules in the kneaded mixture. Only diclofenac, an acidic drug, showed an increased dissolution rate with added casein hydrolysates, and a more rapid dissolution with casein A than with casein B was observed. When the dissolution of prednisolone from kneaded mixture was compared at pH 1.2 and 6.8, the dissolution rate of prednisolone from the casein A kneaded mixture was considerably higher than that of prednisolone powder at both pHs, and the rate from the casein B kneaded mixture was higher only at pH 6.8. The plasma concentration-time profile showed that prednisolone was completely and rapidly absorbed from the casein A kneaded mixture as well as the prednisolone solution. In addition, prednisolone in the kneaded mixture with casein B was more difficult to absorb up to 1 hr after administration in comparison to prednisolone powder. The slow and lowered absorption of prednisolone by casein B might be explained by conversion of casein B to a shorter soluble peptide in the gastrointestinal tract and by the slow dissolution of prednisolone at acidic conditions. The toxicological tests revealed that casein hydrolysate is a safe drug carrier. Consequently, casein hydrolysates might be safely used to control the dissolution rate and bioavailability of a variety of drugs, depending on the peptide length of the casein fragments.

Animals↗
PubMed1998

Stimulatory effects of substance P on CD34 positive cell proliferation and differentiation in vitro are mediated by the modulation of stromal cell function.

Substance P (SP) is a neuropeptide widely distributed in the nervous system. Extensive study has shown SP stimulates production of various cytokines by bone marrow stromal cells, although, the role of SP in hematopoietic phenomena is still unclear. Recently, we established a human cloned stromal cell line, HAS303, which can support hematopoietic stem cell proliferation and differentiation in vitro. We used this culture system to examine the effects of SP. Expression of the mRNAs of neurokinin (NK)-1R, NK-2R and NK-3R, specific SP receptors, on HAS303 cells was demonstrated by the RT-PCR. CD34+ cells isolated from bone marrow were co-cultivated with HAS303 cells in the presence and absence of SP and the total hematopoietic cells and progenitors were counted every 5 days. Introducing SP (10(-8) M) to the co-cultures significantly increased the number of total cells and progenitors compared with control cultures. SP showed no enhancing activity on CD34+ cells cultured alone. SP also stimulated IL-3-dependent colony formation of whole bone marrow MNCs in a soft agar culture system, but showed no such activity on isolated CD34+ cells in this system. These observations suggest that SP stimulated HAS303 cells, activated HAS303 cells, and stimulated the proliferation and differentiation of CD34+ cells. Treating HAS303 cells with SP increased the intracellular Ca2+ concentration and stimulated production of G-CSF, GM-CSF, SCF and IL-6, but not IL-1alpha, IL-1beta and TNF-alpha, but did not enhance proliferation. All these findings suggest that SP mediates hematopoietic cell proliferation and differentiation in vitro by activating stromal cell function.

Antigens, CD34↗