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Biomedical subjects

M Taniguchi

Publications and source records attributed to M Taniguchi.

At least 379 records · Page 21Linked to original sources
PubMed1997

UK-3A, a novel antifungal antibiotic from Streptomyces sp. 517-02: fermentation, isolation, structural elucidation and biological properties.

A novel antifungal antibiotic, UK-3A, was obtained from the mycelial cake of Streptomyces sp. 517-02. UK-3A was very similar in structure to UK-2A, a structural relative of antimycin A. The antifungal spectrum of UK-3A was relatively broad (MICs for yeasts and filamentous fungi: 1.56-6.25 and 0.39-1.56 micrograms/ml, respectively). The cytotoxic activity of UK-3A was weak (IC50: 18-100 micrograms/ml).

Antibiotics, Antineoplastic↗
PubMed1997

Deficiency of c-kit+ cells in patients with a myopathic form of chronic idiopathic intestinal pseudo-obstruction.

OBJECTIVES: Chronic idiopathic intestinal pseudo-obstruction (CIIP) is a syndrome characterized by a failure of intestinal movement, but the cause of dysmotility remains unknown. Because interstitial cells of Cajal (ICCs) are believed to initiate basic contractile activity of the gastrointestinal tract, there is a possibility that changes in ICCs are involved in the development of CIIP. ICCs express c-kit in mice, and it has been reported that the c-kit+ cells, the location and shape of which resemble those in mice, are detected in the human gastrointestinal muscular layer using immunohistochemistry. In the present study, we counted the number of c-kit+ cells in the affected intestine of two patients with myopathic form of CIIP and compared this number with the number of c-kit+ cells in the normal intestine. METHODS: The c-kit+ cells in the external muscle layer were detected by immunohistochemistry, and the number of them was counted under the microscope. Mast cells, which are known to express c-kit, were detected by staining with Alcian blue, and the number of them was also counted. RESULTS: Immunohistochemistry revealed that the distribution pattern of c-kit+ cells resembles that of ICCs in the external muscle layer of normal control subjects. The numbers of c-kit+ cells apart from mast cells in two patients with myopathic form of CIIP decreased to about 3% of those in normal subjects. CONCLUSIONS: The failure of intestinal movement in patients with CIIP, at least in a subpopulation, might be related to a deficiency of c-kit+ cells, probably ICCs.

Adult↗
PubMed1997

Surgical manipulation of mammalian embryos in vitro.

Whole-embryo culture systems are useful in the fields of not only embryology but also teratology, toxicology, pharmacology, and physiology. Of the many advantages of whole-embryo culture, we focus here on the surgical manipulation of mammalian embryos. Whole-embryo culture allows us to manipulate mammalian embryos, similarly to fish, amphibian and avian embryos. Many surgical experiments have been performed in mammalian embryos in vitro. Such surgical manipulation alters the destiny of morphogenesis of the embryos and can answer many questions concerning developmental issues. As an example of surgical manipulation using whole-embryo culture systems, one of our experiments is described. Microsurgical electrocauterization of the deep preaxial mesodermal programmed cell death zone (fpp) in the footplate prevented the manifestation of polydactyly in genetic polydactyly mouse embryos (Pdn/Pdn), in which fpp was abolished.

Animals↗
PubMed1997

[The effect of vasodilator on the occurrence of postoperative shivering and the fall of core temperature].

We evaluated the effect of intraoperative vasodilator therapy on the occurrence of postoperative shivering and the fall of core temperature during 37 abdominal operations by the stepwise multiple regression analysis. As the vasodilator, we used PGE1 at the dose of 0.02-0.05 microgram.kg-1.min-1. In the vasodilator group, postoperative peripheral surface temperature was high and the occurrence of shivering was low. And intraoperative and postoperative core temperatures were not affected by that therapy. From these results, we conclude that intraoperative vasodilator therapy suppressed the occurrence of postoperative shivering without a fall of core temperature.

Adult↗
PubMed1997

Incrustation and uptake of skeletal imaging agent in transitional cell carcinoma.

We present a case of transitional cell carcinoma of the bladder visualized by 99mTc-HMDP bone scintigraphy and suggest possible uptake mechanisms. Pelvic CT demonstrated a sessile bladder tumor with punctate and curvilinear calcifications on the surface areas (incrustation). Technetium-99m-HMDP bone scintigraphy demonstrated intense uptake corresponding to the site of the bladder tumor. Chemisorption of urinary 99mTc-HMDP, rather than of blood-born 99mTc-HMDP, may have occurred at the tumor surface.

Bone Neoplasms↗
PubMed1997

[Clinical and laboratory findings associated with the severity of community-acquired pneumonia].

To clarify the clinical features of severe community-acquired pneumonia, we retrospectively studied 121 patients treated at our hospital. We divided the patients into three groups, based on the severity, of their disease. Patients were put in the "mild" group (n = 56) if they recovered after treatment with antimicrobial agents only, they were put in the "moderate" group (n = 34) if the required oxygen therapy and recovered, and they were put in the "severe" group (n = 31) if they required mechanical ventilation. Age and underlying disease were recorded, as well as signs, symptoms, and laboratory data obtained during the first 24 hours after admission. The data indicated that the following nine findings were associated with the severity of disease: age of at least 65 years, an underlying disease of (31) the respiratory or central nervous system, dyspnea, a pulse rate of at least 90 beats per minute, a respiratory rate of at least 25 breaths per minute, an albumin concentration no greater than 3.5 g/dl, a blood urea nitrogen level of at least 20 mg/dl, a PaO2 no greater than 60 mmHg or an SaO2 no greater than 90%, and a high score on a scale of the extent of roentgenographic evidence of pulmonary infiltrates. Patients in whom these are found be managed carefully.

Adult↗
PubMed1997

[A novel immune system].

We found a novel lymphoid cell lineage, V alpha 14 NKT cell, which is characterized by 1) the expression of both NK1.1 (NK receptor) and an invariant TCR encoded by V alpha 14 and J alpha 281 gene segments; 2) the expression of unusual phenotypes, such as NK1.1+, B220+, Mac-1+, HSA+, CD44+, CD45Rlow and MEL-14low; and 3) the extrathymic development: V alpha 14 NKT cells appear at d9.5 of gestation before thymus development. Moreover, the deletion of the invariant V alpha 14 TCR gene expression caused the lack of NKT cells in vivo, while transgene of the invariant V alpha 14 V beta 8 TCR in the RAG-deficient background resulted in the generation of only V alpha 14 NKT cells without other lymphoid cells. These results indicate the essential requirement of invariant V alpha 14 TCR for the development of NKT cells. Recent studies clearly show that V alpha 14 NKT cells, but not NK cells or T cells are the primary target of IL-12 in the IL-12-mediated tumor rejection.

Animals↗
PubMed1996

Temperature-dependent enhancement of proteolysis in C2C12 myotubes in association with the activation of 26S proteasome.

The effect of temperature on protein metabolism of C2C12 myotubes was investigated in order to estimate the potential effect of fever on muscle catabolism. The half-life of long-lived proteins in C2C12 myotubes was significantly (13%) shorter when incubated at 40 degrees C than at 37 degrees. The activities of cathepsins B and L were not significantly different at 37 and 40 degrees C, nor were the levels of the protein and mRNA of the two cathepsins. In contrast, the chymotrypsin-like activity of 26S proteasome was elevated by 53% at 40 degrees C, compared to that at 37 degrees C, although it was not associated with an increase in the levels of the protein and mRNA of proteasome subunits. mRNA levels of calpain and ubiquitin were not affected by temperature. It is concluded that temperature-dependent enhancement of proteolysis in C2C12 myotubes is associated with an increase in 26S proteasome activity.

Animals↗
PubMed1996

Essential requirement of an invariant V alpha 14 T cell antigen receptor expression in the development of natural killer T cells.

NK1.1+ T [natural killer (NK) T] cells express an invariant T cell antigen receptor alpha chain (TCR alpha) encoded by V alpha 14 and J alpha 281 segments in association with a limited number of V betas, predominantly V beta 8.2. Expression of the invariant V alpha 14/J alpha 281, but not V alpha 1, TCR in transgenic mice lacking endogenous TCR alpha expression blocks the development of conventional T alpha beta cells and leads to the preferential development of V alpha 14 NK T cells, suggesting a prerequisite role of invariant V alpha 14 TCR in NK T cell development. In V beta 8.2 but not B beta 3 transgenic mice, two NK T cells with different CD3 epsilon expressions, CD3 epsilon(dim) and CD3 epsilon(high), can be identified. CD3 epsilon(high) NK T cells express surface V alpha 14/V beta 8 TCR, indicating a mature cell type, whereas CD3 epsilon(dim) NK T cells express V beta 8 without V alpha 14 TCR and no significant CD3 epsilon expression (CD3 epsilon(dim)) on the cell surface. However, the latter are positive for recombination activating gene (RAG-1 and RAG-2) mRNA, which are only expressed in the precursor or immature T cell lineage, and also possess CD3 epsilon mRNA in their cytoplasm, suggesting that CD3 epsilon(dim) NK T cells are the precursor of V alpha 14 NK T cells.

Animals↗
PubMed1996

Development of Valpha4+ NK T cells in the early stages of embryogenesis.

The majority of T lymphocytes start to develop at around day 15 of gestation (d15)-d17 in the thymus and comprise the peripheral repertoire characterized by the expression of polymorphic T-cell antigen receptors (TCRs). Contrary to these conventional T cells, a subset of T cells, called natural killer (NK) T cells (most of them expressing an invariant TCR encoded by the Valpha14Jalpha281 gene with a 1-nt N-region), preferentially differentiates extrathymically and dominates the peripheral T-cell population at a high frequency (5% in splenic T cells and 40% in bone marrow T cells). Here, we investigated the development of NK T cells and found that the invariant Valpha14+ TCR transcripts and the circular DNA created by Valpha14 and Jalpha281 gene rearrangements can be detected in the embryo body at d9.5 of gestation and in the yolk sac and the fetal liver at d11.5-d13.5 of gestation, but not in the thymus, whereas T cells with Valpha1+ TCR expression, a major population in the thymus, were not observed at these early stages of gestation. Fluorescence-activated cell sorter analysis also demonstrated that there exist CD3+ alpha beta+ T cells, almost all of which are Valpha14/Vbeta8+ NK+ T cells, during early embryogenesis. To our knowledge, this demonstrates for the first time that a T lymphocyte subset develops in extrathymic tissues during the early stages of embryogenesis.

Animals↗
PubMed1996

Selective reduction of V alpha 14+ NK T cells associated with disease development in autoimmune-prone mice.

A novel peripheral T cell subset characterized by the expression of a NK marker and invariant TCR encoded by V alpha 14 J alpha 281 gene segments with a 1-base N-region was investigated in relation to autoimmune disease development. First, we observed that invariant V alpha 14+ NK T cells are specifically reduced with aging in C57BL/6 lpr/lpr or MRL lpr/lpr mice, whereas no change was observed in age-matched control C57BL/6 or MRL +/+ mice as determined by FACS analysis and RNase protection assay. This reduction precedes the disease development and could also be detected in other autoimmune disease-prone mice, such as C3H gld/gld and (NZB x NZW)F1 mice. These results suggest that the specific decrease in invariant V alpha 14+ NK T cells correlates strongly with the development of autoimmunity. Second, injection of MRL lpr/lpr mice with anti-V alpha 14 mAb resulted in the early onset and exacerbation of lymphosplenomegaly due to the accumulation of abnormal CD3+ B220+ CD4-CD8- T cells as well as an increase in the titers of anti-dsDNA autoantibodies. These results indicate that V alpha 14+ NK T cells regulate autoimmune responses and play a crucial role in controlling the development of autoimmune diseases.

Age Factors↗
PubMed1996

Intracellular dialysis of cyclic nucleotides induces inward currents in turtle vomeronasal receptor neurons.

Turtle vomeronasal receptor neurons in slice preparations were studied using the patch-clamp technique in the whole-cell and cell-attached configurations. The mean resting potential was -48, and the response to an injected current step consisted of either a single spike or a train of spikes. An injected current of 3-30 pA was required to depolarize the neuron to spike threshold near -50 mV. Voltage-clamped vomeronasal receptor neurons displayed transient inward currents followed by sustained outward currents in response to depolarizing voltage steps. In cell-attached recordings, 10 microM forskolin added to the bath caused a transient increase of spike rate. Intracellular application of cAMP evoked ann inward current in a dose-dependent manner from the neurons voltage clamped at -70 mV; 0.1 mM cAMP was sufficient to elicit an inward current in the neurons. The magnitude of the response to cAMP reached a plateau at 1 mM with an average peak amplitude of 176 +/- 34 pA. Intracellular application of 1 mM cGMP also evoked an inward current with an average peak amplitude of 227 +/- 61 pA. The reversal potentials of the induced components were estimated to be 10 +/- 7 mV for cAMP and -4 +/- 16 mV for cGMP. The reversal potential of the cAMP-induced current in external Cl(-)-free solution was similar to that in normal Ringer's solution, suggesting that Cl- current is not significantly involved in the current. The present results represent the first evidence of cyclic nucleotide-activated conductance in the vomeronasal receptor membranes.

Action Potentials↗
PubMed1996

Evidence for farnesol-mediated isoprenoid synthesis regulation in a halophilic archaeon, Haloferax volcanii.

Farnesol strongly inhibited growth of a halophilic archaeon, Haloferax volcanii, with an IC50 value of only 2 microM (0.4 microgram/ml) in rich medium and 50 nM (0.01 microgram/ml) in minimal medium without lysis. Other isoprenoid alcohols such as isopentenol, dimethylallyl alcohol, geraniol, and geranylgeraniol at 500 microM did not affect its growth. Mevalonate, which is the precursor of all isoprenoid membrane lipids in archaea, led to recovery of the growth inhibition of H. volcanii, but acetate had no such effect. Farnesol inhibited incorporation of acetate, but not mevalonate, into the lipid fraction. These results suggest that farnesol inhibited the biosynthetic pathway from acetate (acetyl-CoA) to mevalonate. Farnesol is known to be derived from the important intermediate of isoprenoids, farnesyl diphosphate (FPP), and found in neutral lipid fraction from this archaeon. Moreover, the cell-free extracts from H. volcanii could phosphorylate farnesol with ATP to generate farnesyl monophosphate and FPP. We conclude that farnesol-mediated isoprenoid synthesis regulation system by controlling farnesol concentration is present in H. volcanii.

Acetates↗
PubMed1996

Monoclonality of B-cell lineage in primary pulmonary lymphoma demonstrated by immunoglobulin heavy chain gene sequence analysis of histologically non-definitive transbronchial biopsy specimens.

Immunoglobulin heavy chain (IgH) gene rearrangements were amplified in transbronchial lung biopsy (TBLB) specimens taken from five patients with primary lymphoma of the lung in whom the diagnosis was established by surgical specimens. By histopathological analysis of TBLB specimens, only two of the five cases were diagnosed as lymphoma, the other three cases being classified as equivocal due mainly to low levels of cellular atypia and to artefactual distortion. All five TBLB specimens, as well as the subsequent surgical specimens, showed a sharp monoclonal band of IgH gene rearrangement on electrophoresis of polymerase chain reaction (PCR) products. By contrast, three surgical biopsy specimens from cases of lymphoid interstitial pneumonia (LIP) showed smear polyclonal bands. No clonal rearrangements were detected in six non-neoplastic controls, including five cases of chronic bronchitis and one of sarcoidosis. The PCR products of three of the lymphoma cases were sequenced from both TBLB and surgical specimens. In all three cases, there was dominant expression of a particular rearrangement, assumed to be tumour-derived. In each case, the major clones derived from the TBLB and the surgical specimen were identical. In both lymphoma and LIP cases, more frequent usages of JH4 and JH6 were evident. The diagnosis of lymphoma can be confirmed on TBLB specimens by use of this technique.

Adult↗
PubMed1996

Isolation, characterization and expression of cDNA clones encoding a mitochondrial malate translocator from Panicum miliaceum L.

Three cDNA clones that hybridize to a partial rice cDNA that show similarity to bovine mitochondrial 2-oxoglutarate/malate translocator were isolated from leaves of Panicum miliaceum L. (proso millet), an NAD-malic enzyme-type C4 plant. The nucleotide sequences of the clones resemble each other, and some of the isolated cDNAs contained extra sequences that seemed to be introns. The predicted proteins encoded by the cDNAs have 302 amino acids and molecular weights of 32211 and 32150. The hydrophobic profile of the amino acid sequence predicted the existence of six transmembrane alpha-helices that is a common property of members in the mitochondrial transporter family. The predicted amino acid sequence showed the highest similarity with that of the 2-oxoglutarate/malate translocator from mammalian mitochondria. An expression plasmid containing the coding region of the cDNAs was used to over-express recombinant protein with a C-terminal histidine tag Escherichia coli, which was affinity purified. The antibody against the recombinant protein cross-reacted with proteins of 31-32 kDa in the membrane fraction from P. miliaceum mitochondria, but not with the chloroplast fraction. The recombinant protein reconstituted in liposomes efficiently transported malate, citrate, and 2-oxoglutarate.

Amino Acid Sequence↗