Absence of the anomalous second length scale in the bulk of a terbium single crystal.
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Journal Article↗
Biomedical subjects
K Hirota
Publications and source records attributed to K Hirota.
Chinese hamster ovary cells expressing a novel type of acetylated low density lipoprotein receptor. Isolation and characterization.
Macrophage scavenger receptors mediate the recognition of a wide range of negatively charged macromolecules including acetylated low density lipoproteins (AcLDL). Chinese hamster ovary (CHO) cells were cultured in the presence of increasing concentrations of simvastatin, a cholesterol biosynthesis inhibitor, and AcLDL as the sole source of exogenous lipoproteins. The cells surviving under these conditions specifically bound 125I-labeled AcLDL with high affinity and degraded them via an endocytic pathway. Unexpectedly, the association and degradation of 125I-labeled AcLDL by these CHO cells were not inhibited by dextran sulfate, fucoidan, and polyinosinic acid, competitors of macrophage scavenger receptors, but were completely inhibited by maleylated bovine serum albumin. Furthermore, these cells effectively took up negatively charged liposomes containing acidic phospholipids such as phosphatidylserine and phosphatidic acid, whereas CHO cells expressing macrophage scavenger receptors did not. AcLDL and negatively charged liposomes were cross-competed with each other. Northern blot analysis using the cDNA for the macrophage scavenger receptor revealed that these CHO cells did not express this receptor. From these observations, we conclude that the isolated CHO cells express a novel type of AcLDL receptor, which is distinct from macrophage scavenger receptors with respect to ligand specificity and competitor sensitivity.
Albumins↗
Neuronal specificity of subtype SQSC1 of squid putative sodium channel.
The distribution of SQSC1 mRNA in tissues of squid Loligo bleekeri was studied by the blot hybridization method. The complete cDNA for the coding region of SQSC1, the invertebrate putative sodium channel, was prepared from squid optic lobe (Sato and Matsumoto, Biochem. Biophys. Res. Comm. 186, 61-68, 1992). Transcriptional products of the SQSC1 gene were found to consist of two main different lengths (12 and 9 kb). The transcriptional products were detected in all the nervous tissues examined: optic lobes, cerebral ganglia and giant stellate ganglia. However, it was not detected in the muscle, suggesting the SQSC1 gene is specific for sodium channels of squid nerve cells. SQSC1 appears more widely distributed in the nervous system than GFLN1 which they reported as expressed specifically in stellate ganglion of the squid (Rosenthal and Gilly, Proc. Natl. Acad. Sci. USA 90, 10026-10030, 1993).
Alternative Splicing↗
Structure of the mouse thioredoxin-encoding gene and its processed pseudogene.
Thioredoxins (TXN) are small proteins with various biological functions, such as redox regulation, found in many species including bacteria, plants and animals. We previously reported the isolation of the TXN-encoding cDNAs from human and mouse. In order to elucidate the functions of the mammalian TXN system, we planned to generate Txn knockout mice, and cloned the genomic DNA fragments using the Txn cDNA as a probe. The Txn gene extends over 12 kb and consists of five exons separated by four introns. Detailed Southern analyses revealed that the mouse genome contains only one active Txn gene and one processed pseudogene (Txn-ps1), in contrast to some species which have families of active TXN-encoding genes. These findings should help to understand Txn itself, and provide a basis for transgenic experiments by gene targeting.
Amino Acid Sequence↗
Interleukin-6 stimulates cell proliferation of rat pituitary clonal cell lines in vitro.
We investigated the effect of recombinant human IL-6 (rhIL-6) on cell proliferation using the MtT/E rat pituitary tumor cell line, which was recently established by Inoue et al. This cell line expresses the homeodomain protein Pit-1/GHF 1 and does not produce any significant amount of pituitary hormones, but retains its tumorigenicity by back-transplantation into rats, resulting in production of prolactin. MtT/E cells were seeded into Falcon 24-well plates at a density of 2 x 10(4) cells/well in a cultured medium, containing 10% horse serum and 2.5% fetal bovine, with test drug. After four-days (12 days for the time-course study) incubations, the cells were counted using a hemocytometer. Incubation for 4 days with rhIL-6 caused concentration-dependent stimulation of MtT/E cell growth and [3H]-thymidine incorporation into MtT/E cells. Addition of 20 ng/ml rhIL-6 to the culture medium stimulated MtT/E cell growth in a time-dependent manner, withdrawal of rhIL-6 from the culture medium reduced MtT/E cell growth, and re-addition of rhIL-6 to the culture medium again stimulated MtT/E cell growth. Among the cytokines tested, granulocyte colony-stimulating factor (rh G-CSF) also showed a slight but significant mitogenic activity on the MtT/E cells. Analysis of 125I-rhIL-6 binding to the MtT/E cells indicated a dissociation constant of 0.953 x 10(-9) mmol/l and the presence of 968 binding sites per cell.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Induction of ADF/TRX by oxidative stress in keratinocytes and lymphoid cells.
Adult T-cell leukemia-derived factor (ADF)/human thioredoxin (TRX) has thiol-dependent reducing activities and is known to have regulatory roles on the DNA-protein interaction and cell activation. Inducive effect of ultraviolet (UV) has been indicated because of the enhanced expression of ADF/TRX in epidermal cells of sun-exposed skin, as determined by immunohistochemical staining with antibody against recombinant ADF (rADF). We studied the effect of UVB irradiation and other oxidative stress on the expression of ADF/TRX in epithelial cells as well as lymphoid cells, as HTLV-1 and Epstein-Barr virus-transformed lymphoid cells constitutively produce ADF/TRX. Using immunohistochemical staining anti-ADF antibody, the enhancement of ADF/TRX expression on primary culture of human keratinocytes was demonstrated, 12 h after 20 mJ/cm2 UVB irradiation. Western blot analysis of the ADF/TRX protein in the cell lysates also showed the significant induction. In in situ hybridization, induction of ADF/TRX mRNA was detected after 4 h of UV exposure. ADF/TRX was also induced in a HTLV-1 (+) T-cell line, MT-1, by UVB or H2O2 dose dependently. The augmentation of ADF/TRX was observed 6 h after treatment of H2O2.
Blotting, Western↗
Perimenopausal changes in serum lipids and lipoproteins: a 7-year longitudinal study.
Although cross-sectional studies suggest considerable influence of menopause on serum lipids and lipoproteins in women, it is not exactly clear. During our 7-year longitudinal study, serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and low-density lipoprotein (LDL) cholesterol were measured in 16 healthy perimenopausal women (aged 47-56 years at menopause) who had undergone annual examinations 4 years before and 3 years after menopause under a health examinations system in Osaka. Longitudinal design enabled us to study the natural course of serum lipids and lipoproteins. The results show that from 4 years before to 1 year after menopause, the serum concentration of total cholesterol and LDL cholesterol increased on average by 25 mg/dl (14%) and 20 mg/dl (19%), respectively. Serum concentrations of triglycerides and of HDL cholesterol remained virtually unchanged during the perimenopausal and postmenopausal periods. It was concluded that serum lipids and lipoproteins are thus significantly altered as a consequence of menopause, resulting in a more atherogenic profile in the postmenopausal period.
Arteriosclerosis↗
Immunochemical analysis and localisation of a cell wall antigen of Streptococcus rattus with a specific monoclonal antibody.
A monoclonal antibody specific to a cell wall antigen of Streptococcus rattus (S. rattus) was prepared after cell fusion of mouse myeloma cells to the spleen cells of mice immunized with whole cells of strain FA1. The monoclonal antibody reacted with a crude and purified polysaccharide antigen of S. rattus in precipitin reactions as well as in a solid phase enzyme assay (EIA). It also reacted in the EIA with whole cells of S. rattus strains, but did not react with any other species of the mutans group or of other oral and streptococcal species. Moreover, among many haptenic sugars and their derivatives tested, D-galactosamine and D-glucosamine strongly inhibited the reaction in a competitive enzyme immunoassay using the purified antigen and whole cells, indicating that the type-specific antigenic determinant of the organism has a structure similar to the amino group of the sugar molecules. Furthermore, immunoelectron microscopy revealed that the antigen epitopes formed an irregular fibrous structure over the entire surface of individual cells.
Animals↗
Alteration in the reactivity of sphingomyelin in mitogen-stimulated lymphocytes.
The antigens for a monoclonal antibody, VJ-41, established by alloimmunization of B10.A(3R) mice with lymphocytes from B10.A(5R) mice and screening of its reactivity toward Con A-stimulated human T lymphocytes, were found to be phosphorylcholine-containing ceramides (sphingomyelin) and disaturated fatty acyl glycerol (phosphatidyl-choline, PC), but neither deacylated sphingomyelin nor unsaturated fatty acid-containing PC reacted with the antibody. Although the reactivity of disaturated fatty acyl PC increased with increasing chain length, that of sphingomyelin was stronger than that of di-20:0-PC. The binding of the antibody to Con A-stimulated lymphocytes was inhibited by sphingomyelin-containing liposomes, but not by di-18:0-PC-containing ones, and the concentration of sphingomyelin in Con A-stimulated human T-lymphocytes was the same as that in non-stimulated ones, indicating that the reactivity of sphingomyelin in lymphocytes is altered by Con A-stimulation.
Animals↗
Posterior hypothalamic noradrenaline release during emergence from sevoflurane anesthesia in rats.
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Anesthesia Recovery Period↗
Equine parentage testing by microsatellite locus at chromosome 1q2.1.
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Alleles↗
ECA-3: equine (CA) repeat polymorphism at chromosome 2p1.3-4.
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Alleles↗
Acute myeloblastic leukaemia without Philadelphia chromosome developing after interferon therapy for chronic myelocytic leukaemia with Philadelphia chromosome.
We report a patient who developed Philadelphia chromosome negative acute myeloblastic leukaemia with trisomy 8 and trisomy 11 after receiving treatment with alkylating agents and interferon for chronic myelocytic leukaemia positive for Philadelphia chromosome. Leukaemic cells were positive for myeloperoxidase and expressed CD13, CD33 and DR; some expressed CD2, CD4 and CD34. The fluorescence in situ hybridization method revealed that bcr-abl fusion genes were absent from > 90% of the bone marrow cells. The major bcr rearrangement was not detected by Southern blot analysis. We conclude that the leukaemic cells negative for Philadelphia chromosome may have developed as a result of treatment with alkylating agents and interferon in the present case.
Aged↗
Topical ketamine inhibits albumin extravasation in chemical peritonitis in rats.
BACKGROUND: As ketamine has local anaesthetic actions and local anaesthetics are known to have anti-inflammatory effects, ketamine could be expected to be an anti-inflammatory agent. Here we sought to determine whether ketamine is indeed anti-inflammatory in chemical peritonitis induced by HCl in rats. METHODS: Peritonitis was elicited by applying 0.02 M HCl on the surface of the cecum or appendix and quantified by measuring the extravasation of intravenously injected Evan's Blue bound to albumin extracted from those tissues. Three experimental sets were performed. In the first set, four groups of 10 rats each received: 1%, 2%, and 4% ketamine and 1% lidocaine. In the same animal, before induction of peritonitis one area was topically pre-treated with 0.9% saline (control site) and another area was topically pre-treated with 1%, 2% or 4% ketamine or 1% lidocaine (experimental site). In the second set, two groups of 10 rats each received: 2% ketamine or 1% lidocaine. Ten min after the induction of peritonitis, the control site was topically treated with 0.9% saline, while the experimental site was treated with 2% ketamine or 1% lidocaine. In the third set 20 rats, divided into two groups, were pre-treated either with 2% S(+)ketamine or 2% R(-)ketamine before the induction of peritonitis instead of the previously employed racemic version of the drug. RESULTS: Treatment of the cecum or appendix areas with ketamine or lidocaine before the induction of peritonitis decreased the extravasation of Evan's Blue-albumin from 5.7 +/- 0.7 micrograms/100 mg tissue to 4.5 +/- 0.8, N.S. with 1% ketamine; from 5.9 +/- 0.8 to 4.1 +/- 0.7, P < 0.01 with 2% ketamine; from 4.8 +/- 0.7 to 3.5 +/- 0.6, P < 0.05 with 4% ketamine and from 5.9 +/- 0.6 to 3.6 +/- 0.8, P < 0.01 with 1% lidocaine. Treatment of the areas of peritonitis with 2% ketamine or 1% lidocaine decreased the extravasation of Evan's Blue-albumin from 5.6 +/- 0.5 micrograms/100 mg tissue to 4.4 +/- 0.6, P < 0.05 and from 6.0 +/- 0.8 to 5.0 +/- 0.7, P < 0.01. Administration of the isomer S(+)ketamine to colonic areas before the induction of peritonitis reduced the extravasation of Evan's Blue-albumin from 6.5 +/- 0.7 micrograms/100 mg tissue to 4.1 +/- 0.6, P < 0.01; while the isomer R(-)ketamine was inactive. CONCLUSIONS: These results indicate that topically applied ketamine inhibited the development of chemical peritonitis. This action of racemic ketamine was due to the isomer S(+)ketamine.
Administration, Topical↗
Ketamine inhibits contractile responses of intestinal smooth muscle by decreasing the influx of calcium through the L-type calcium channel.
During the inflammatory response, tissues release histamine (H), substance P, serotonin (5-HT), prostaglandins and kinins, agents that mediate manifestations of inflammation such as pain, vasodilation, increased capillary permeability and smooth muscle contraction. In this study we investigated whether racemic (R[+]) ketamine (K) and its isomers are spasmolytic on intestinal smooth muscle contracted by inflammatory mediators, and whether the spasmolytic effect of K is related to changes in calcium influx through the L-type calcium channel or to an interaction of K with opioid receptors. We measured the contractions of guinea-pig ileum mounted in an organ bath containing Tyrode's solution gassed with 95% O2/5% CO2 at 37 degrees C. In the first protocol we determined the effect of K and its isomers on contractions induced by five mediators: 10(-7) M H, 10(-8) M substance P, 10(-8) M neurokinin A, 5 x 10(-9) M bradykinin and 5 x 10(-7) M 5-HT. For each of these mediators, we plotted concentration-response curves for the inhibitory effect of K, and from regression fitting of these curves, we calculated the IC50 concentration of K that inhibited the contraction by 50%). In the second protocol we measured the contraction induced by the calcium ionophore A23187 (5.0 x 10(-6) M), both alone and after 1.8-7.2 x 10(-4) M R(+/-)K. Then we examined how the inhibition caused by R(+/-)K was affected by increases in the concentration of extracellular calcium by adding calcium (1.8-7.2 x 10(-3) M).(ABSTRACT TRUNCATED AT 250 WORDS)
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
Cross-reactivity between human sialyl Lewis(x) oligosaccharide and common causative oral bacteria of infective endocarditis.
The expression of sialy-Lewis(x) (sLe(x); Neu5Ac alpha 2-3 Gal beta 1-4) (Fuc alpha 1-3) GlcNAc-R) on oral bacteria producing infective endocarditis was determined by a whole-cell enzyme linked immunosorbent assay and an immunoelectron microscopy using the well-characterized anti-sLe(x) monoclonal antibody SNH-3 (mAb SNH-3; IgM class). mAb SNH-3 reacted strongly with whole cells of oral bacteria: Streptococcus sanguis, Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Streptococcus intermedius, Streptococcus constellatus, Streptococcus anginosus, Streptococcus pyogenes, Actinobacillus actinomycetemcomitans, Eikenella corrodens and Porphyromonas gingivalis. The negatively stained immuno-electron micrograph of Streptococcus pyogenes showed many reactive gold particles on the cell surface. Our findings demonstrated the existence of immunologic mimicry between the sLe(x) oligosaccharide and cell surface antigens of many species associated with infective endocarditis. We propose the hypothesis that if these bacteria escape their normal habitats, the surface components that mimic the sLe(x) oligosaccharide might bind to host antigens of the selectin family which could promote binding to endothelial cells and, consequently, initiation of the events leading to infective endocarditis.
Antibodies, Monoclonal↗
Oxytocin stimulates mitogen-activated protein kinase activity in cultured human puerperal uterine myometrial cells.
The regulation of mitogen-activated protein (MAP) kinase by oxytocin in cultured human uterine myometrial cells was investigated. Oxytocin caused the rapid stimulation of MAP kinase activity detected in 32P incorporation of MAP-2. Oxytocin also stimulated the phosphorylation of MAP kinase detected in incorporation of [32P]orthophosphate into MAP kinase. Furthermore, oxytocin induced the tyrosine phosphorylation of MAP kinase. The oxytocin-dependent increase in the tyrosine phosphorylation of MAP kinase displayed a transient time course and was dependent on the concentration of oxytocin applied to the cells. Furthermore, we examined the mechanism by which oxytocin induced MAP kinase phosphorylation. Islet-activating protein (100 ng/ml), which inactivates Gi/Go proteins, blocked the oxytocin-induced phosphorylation of MAP kinase. Moreover, 1 microM ritodrine, which is known to relax uterine muscle contraction, attenuated oxytocin-induced MAP kinase activity and phosphorylation. These results provide evidence that oxytocin acutely activates MAP kinase through an islet-activating protein-sensitive G-protein in human uterine myometrial cells, suggesting that this new pathway may play an important role in the biological action of oxytocin on these cells.
Calcium-Calmodulin-Dependent Protein Kinases↗
Urinary excretion of alpha- and beta-isomers of biliverdin-IX in humans.
The distribution and relative proportions of the four isomers of alpha-, beta-, gamma- and delta-biliverdin-IX were investigated using urinary samples from seven healthy adults. The biliverdins from samples were adsorbed on talc, and the adsorbed biliverdins were then soaked in a solution of methanol and concentrated sulfuric acid for derivation to the dimethyl esters. The esters were passed to a reversed-phase cartridge for clean-up, then quantitated by HPLC on a reversed-phase column. The analyses revealed that the biliverdins in 24-h urine were comprised of 6.4 +/- 2.5 nmol alpha- and 9.3 +/- 5.4 nmol beta-isomers. The HPLC analyses suggested the presence of a delta-isomer in a much smaller amount, but no gamma-isomer was detected. The identifications of alpha- and beta-isomers were performed with co-chromatography and absorption spectra.
Adult↗