Familial scimitar syndrome: three-dimensional visualization of anomalous pulmonary vein in young sisters.
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Adult↗
Biomedical subjects
M Kobayashi
Publications and source records attributed to M Kobayashi.
Development of a new system for prediction of drug absorption that takes into account drug dissolution and pH change in the gastro-intestinal tract.
A new system for prediction of drug absorption that takes into account drug dissolution and pH change in the gastro-intestinal tract was developed. In this new system, a drug (solid form) is added into a drug-dissolving vessel (pH 1.0) and the dissolved drug is transferred to a pH adjustment vessel (pH 6.0). Then the drug solution is transferred to the apical surface of Caco-2 cells, and the permeation rate of the drug across a Caco-2 monolayer is determined. This system was able to predict the oral absorption ratios of ten water-soluble drugs in humans. Using this system, it was predicted that drugs that permeated Caco-2 at a rate of more than 0.1% of the dose in 200 min would be almost completely absorbed after oral administration in humans. For a drug whose permeation ratio was less than 0.03%, the absorption ratio was predicted to be less than 30%. This system also enabled prediction of the absorption rate and variability in the absorption of albendazole, a drug with poor water solubility. It also enabled assessment of the improvement in absorption using a solid dispersion of albendazole-polymers that improved the water solubility. The results suggest that this system is useful for oral absorption screening of new drugs and pharmaceutical products.
Administration, Oral↗
Total synthesis of agosterol A: an MDR-modulator from a marine sponge.
The first total synthesis of agosterol A, a modulator of multidrug resistance (MDR) mediated by P-gp and MRP1, and isolated from a marine sponge, was achieved from ergosterol by utilizing a regioselective epoxy-cleavage reaction and regioselective dehydroxylation as the key reactions.
Animals↗
Study on the lubrication mechanism of natural joints by confocal laser scanning microscopy.
Natural joints have an excellent lubricating function, but the detailed mechanism is still unclear. To clarify this lubricating mechanism, we observed the behavior of the cartilage surface under the physiological loading condition with confocal laser scanning microscopy in normal and osteoarthritis (OA) cartilage rabbit specimens. Even with a considerable loading condition, in both natural and OA cartilage, the fluid pool area coexisted with the direct contact area. In the junction from the direct contact area to the fluid area, there was a third area with a liquid-crystal arrangement. In OA cartilage, these areas were generally irregular and small. These results suggest that a lubrication system in the fluid phase, such as squeeze film lubrication, might work under severe pressure in normal cartilage, and hyaluronic acid macromolecules in the synovial fluid might form a liquid-crystal structure and support pressure on the cartilage surface, whereas these systems did not affect the OA cartilage.
Animals↗
Immobilization stress-induced thymocyte apoptosis in rats.
Immobilization of rats is a well known model of emotional stress. We studied apoptosis in rat thymocytes during immobilization for 2-8 hours (h). Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells increased with time of immobilization. The positive cells increased significantly after 2 h and comprised about 33% of total cells after 8 h. The apoptotic cells aggregated as scattered foci predominantly in the cortex of the thymus and diffusely distributed with time of the stress. The DNA laddering also increased with time of immobilization, which was inhibited by a glucocorticoid receptor antagonist, RU-486. These results suggest that the emotional stress evoked by immobilization induces thymocyte apoptosis through glucocorticoid overflow.
Animals↗
Reactivation of feline foamy virus from a chronically infected feline renal cell line by trichostatin A.
Although acute infection of feline foamy virus (FeFV) is normally highly cytopathogenic in Crandell feline kidney (CRFK) cells, a noncytopathic persistent infection was established in the cells after cocultivation of the initially infected cells with uninfected cells four times. To investigate reactivation of persistent infection, CRFK cells chronically infected with FeFV were treated with trichostatin A (TA), a histone deacetylase inhibitor. TA induced higher FeFV production from the Coleman strain carrier culture and also induced marked syncytium formation. In contrast, human foamy virus, which contains less homologous long terminal repeat (LTR) and putative internal promoter (IP) sequences, persistently infecting baby hamster kidney cells was not reactivated by TA. The Sammy-1 strain of FeFV, from which a part of the U3 region in the LTR is naturally deleted, showed less reactivation. The Coleman LTR promoter-based beta-Gal-expressing plasmid was activated in the persistently Coleman-infected cells in the presence of TA, whereas the Sammy-1 LTR was not activated. Furthermore, the amounts of Gag protein expressed did not change in the presence or absence of TA. Because the putative IP region was very similar between the two strains, the initiation by TA is relatively specific for LTR sequences, and, therefore, histone deacetylation is at least in part responsible for reactivation of FeFV from carrier cell culture.
Animals↗
Decreased topoisomerase IIalpha expression confers increased resistance to ICRF-193 as well as VP-16 in mouse embryonic stem cells.
To elucidate the relationship between topoisomerase (topo) II expression and sensitivity to anti-topo II drugs in mammalian cells, we generated mouse embryonic stem cell mutants heterozygous for the topo IIalpha gene by gene targeting. The level of topo IIalpha in the heterozygous cells reduced to one-half of that found in wild-type cells, while topo IIbeta levels were similar in both cell types. Importantly, the heterozygous cells exhibited an increased resistance to ICRF-193 as well as VP-16, suggesting that ICRF-193, like VP-16, exerts its cytotoxicity through converting topo II to a poison.
Animals↗
Detection of early gastric cancer by a real-time autofluorescence imaging system.
A light-induced fluorescence endoscopy in the gastrointestinal tract system was used in 52 patients with 54 lesions (33 early gastric cancers, 21 benign lesions) to assess its ability to detect early gastric cancer. Comparing the images with the histological findings, 21 of the 33 carcinomas appeared dark red, ten had a mixed pattern of dark red and white, and two could not be detected. Of the 21 benign lesions, 18 appeared light blue, as do normal mucosa, with this system. In 85% of the cancer lesions (28/33), cancer extension was correctly detected. The sensitivity and specificity were 94 and 86%, respectively. Real-time autofluorescence endoscopy is a useful adjunct to conventional white-light endoscopy for detecting early gastric cancer.
Carcinoma↗
Drug release from and mechanical properties of press-coated tablets with hydroxypropylmethylcellulose acetate succinate and plasticizers in the outer shell.
Dissolution profiles of diltiazem hydrochloride (DIL) contained in core tablets from press-coated (PC) tablets with hydroxypropylmethylcellulose acetate succinate (HPMCAS) and plasticizers-adsorbent in the outer shell were investigated. Although, on the addition of triethyl citrate (TEC), triacetin (TA), and acetyltriethy citrate (ATEC) as plasticizers, DIL release was suppressed completely in first fluid (pH 1.2) for 10 h, it was not suppressed in HPMCAS on the addition of dibutyl sebacate (DBS) and acetylated monoglyceride. On the other hand, DIL in second fluid (pH 6.8) was released rapidly after a lag time in all the PC tablets. Water-soluble plasticizers such as TEC, TA, and ATEC showed greater compatibility to HPMCAS, and the results were consistent with suppression of DIL release in first fluid. Furthermore, as to PC tablets with HPMCAS and TEC-adsorbent, the DIL release in second fluid did not change after pretreatment in first fluid by the paddle-beads methods. To evaluate the resistance of the outer shell against such a mechanical impact, tablets with HPMCAS, HPMCAS and TEC- or DBS-adsorbent (H, HT, or HD tablets, respectively) were prepared. In compressive load-strain curves after immersion in first fluid, wet crushing strength was lower in the order of HT > H > HD tablets. Also, the curves of HT tablets at 3 and 21 h after immersion were quite different from those of other tablets, and it was hard to find crushing points. These results suggested that the resistance of the outer shell was due to plastic deformation properties involving some interaction between HPMCAS and TEC.
Cardiovascular Agents↗
Discovery of a novel enzyme, isonitrile hydratase, involved in nitrogen-carbon triple bond cleavage.
Isonitrile containing an N triple bond C triple bond was degraded by microorganism sp. N19-2, which was isolated from soil through a 2-month acclimatization culture in the presence of this compound. The isonitrile-degrading microorganism was identified as Pseudomonas putida. The microbial degradation was found to proceed through an enzymatic reaction, the isonitrile being hydrated to the corresponding N-substituted formamide. The enzyme, named isonitrile hydratase, was purified and characterized. The native enzyme had a molecular mass of about 59 kDa and consisted of two identical subunits. The enzyme stoichiometrically catalyzed the hydration of cyclohexyl isocyanide (an isonitrile) to N-cyclohexylformamide, but no formation of other compounds was detected. The apparent K(m) value for cyclohexyl isocyanide was 16.2 mm. Although the enzyme acted on various isonitriles, no nitriles or amides were accepted as substrates.
Carbon↗
The homeobox protein Six3 interacts with the Groucho corepressor and acts as a transcriptional repressor in eye and forebrain formation.
Six3 is a vertebrate homeobox gene that is expressed in the anterior neural plate and eye anlage. We overexpressed a dominant transcriptional activator or repressor form of Six3 in zebrafish embryos to analyze their effect on eye and forebrain formation. RNA injection of the activator form of Six3 into zebrafish embryos caused reduction of the expression domains for rx2, pax2, and emx1 in the anterior neural plate, resulting in eye and forebrain hypoplasia. On the other hand, overexpression of the repressor form of Six3 or wild-type Six3 showed phenotypes opposite to those of the activator form. We found that Six3 has eh1-related motifs, motifs crucial for transcriptional repression function of Drosophila engrailed which plays a role in tethering the Groucho corepressor to the promoters. We isolated one of the zebrafish Groucho family genes, grg3, and demonstrated an interaction between Six3 and Grg3 using yeast two-hybrid analysis. Point-mutations in the eh1-related motifs in Six3 reduced both its eye and forebrain enlarging activities and its interaction with Grg3. These results strongly argue that Six3 functions as a Groucho-dependent repressor in eye and forebrain formation. Furthermore, zebrafish Six2 and Six4 also interacted with Grg3, implying a conserved function among the Six family proteins as transcriptional repressors.
Amino Acid Motifs↗
Ischemic preconditioning upregulates vascular endothelial growth factor mRNA expression and neovascularization via nuclear translocation of protein kinase C epsilon in the rat ischemic myocardium.
Ischemic preconditioning (IP) exerts cardioprotection through protein kinase C (PKC) activation, whereas myocardial ischemia enhances vascular endothelial growth factor (VEGF) mRNA expression. However, the IP effect or the involvement of PKC on the VEGF expression is unknown in myocardial infarction. We investigated whether IP enhances VEGF gene expression and angiogenesis through PKC activation in the in vivo myocardial infarction model. Sprague-Dawley rats were assigned into the following 3 groups: the sham group; the IP group, which underwent 3 cycles of 3 minutes of ischemia and 5 minutes of reperfusion (IP procedure); and the non-IP group. The latter 2 groups were subsequently subjected to left anterior descending coronary artery occlusion. To examine the involvement of PKC, the PKC inhibitor chelerythrine (5 mg/kg) or bisindolylmaleimide (1 mg/kg) was injected intravenously before the IP procedures. PKCepsilon was translocated to the nucleus after 10 minutes of ischemia after the IP procedure but was not translocated in the non-IP and the sham groups. VEGF mRNA expression 3 hours after infarction was significantly higher in the IP group than in the non-IP and the sham groups. Capillary density in the infarction was significantly higher, whereas the infarct size was smaller in the IP group than in the non-IP group at 3 days of infarction. Chelerythrine but not bisindolylmaleimide blocked all of the IP effects on the nuclear translocation of PKCepsilon, enhancement of VEGF mRNA expression and angiogenesis, and infarct size limitation. These results show that IP may enhance VEGF gene expression and angiogenesis through nuclear translocation of PKCepsilon in the infarcted myocardium.
Active Transport, Cell Nucleus↗
Glutathione-dependent binding of a photoaffinity analog of agosterol A to the C-terminal half of human multidrug resistance protein.
MRP1 is a 190-kDa membrane glycoprotein that confers multidrug resistance (MDR) to tumor cells. MRP1 is characterized by an N-terminal transmembrane domain (TMD(0)), which is connected to a P-glycoprotein-like core region (DeltaMRP) by a cytoplasmic linker domain zero (L(0)). It has been demonstrated that GSH plays an important role in MRP1-mediated MDR. However, the mechanism by which GSH mediates MDR and the precise roles of TMD(0) and L(0) are not known. We synthesized [(125)I]11-azidophenyl agosterol A ([(125)I]azidoAG-A), a photoaffinity analog of the MDR-reversing agent, agosterol A (AG-A), to photolabel MRP1, and found that the analog photolabeled the C-proximal molecule of MRP1 (C(932-1531)) in a manner that was GSH-dependent. The photolabeling was inhibited by anticancer agents, reversing agents and leukotriene C(4). Based on photolabeling studies in the presence and absence of GSH using membrane vesicles expressing various truncated, co-expressed, and mutated MRP1s, we found that L(0) is the site on MRP1 that interacts with GSH. This study demonstrated that GSH is required for the binding of an unconjugated agent to MRP1 and suggested that GSH interacts with L(0) of MRP1. The photoanalog of AG-A will be useful for identifying the drug binding site within MRP1, and the role of GSH in transporting substrates by MRP1.
Base Sequence↗
Association of AIM, a novel apoptosis inhibitory factor, with hepatitis via supporting macrophage survival and enhancing phagocytotic function of macrophages.
A hallmark of many inflammatory diseases is the destruction of tissue cells by infiltrating hematopoietic cells including lymphocytes, neutrophils, and macrophages. The regulation of apoptosis of both target tissue cells and the infiltrating cells is one of the key events that defines the initiation and the progression of inflammation. However, the precise picture of the apoptosis regulation of the cells at the inflammatory sites is still unclear. We recently isolated a novel apoptosis inhibitory factor, termed AIM, which is secreted exclusively by tissue macrophages. In this report, we present unique characteristics of AIM associated with liver inflammation (hepatitis), identified by introducing an experimental hepatitis in both AIM-transgenic mice, which overexpress AIM in the body, and normal mice. First, endogenous AIM expression in macrophages is rapidly increased in response to inflammatory stimuli. Second, AIM appears to inhibit the death of macrophages in the inflammatory regions, judging by the remarkably increased number of macrophages observed in the liver from transgenic mice. In addition, we show that AIM also enhances the phagocytosis by macrophages, which emphasizes the multifunctional character of AIM. All these findings strongly provoke an idea that AIM may play an important role in hepatitis pathogenesis in a sequential manner; first AIM expression is up-regulated by inflammatory stimuli, and then in an autocrine fashion, AIM supports the survival of infiltrating macrophages as well as enhances phagocytosis by macrophages, which may result in an efficient clearance of dead cells and infectious or toxic reagents.
Animals↗
Glycyrrhizin restores the impaired IL-12 production in thermally injured mice.
Mice 6 days after thermal injury (TI-mice) did not respond to lipopolysaccharide (LPS) stimulation for production of serum interleukin 12 (IL-12; 2 h after LPS stimulation, <20 pg/ml in TI-mice; 1091+/-162 pg/ml in normal mice). However, 2 h after LPS stimulation, 1456+/-118 pg/ml of IL-12 were demonstrated in sera of TI-mice previously treated with a 10 mg/kg i.p. dose of glycyrrhizin (GR). IL-12 was not induced by LPS in sera of normal mice inoculated with burn-associated type 2 T cells (IL-4/IL-10-producing CD8+CD11b+TCRgamma/delta+T cells isolated from spleens of TI-mice). However, IL-12 production was induced by LPS in sera of these mice previously treated with GR or a mixture of monoclonal antibodies (mAbs) for type 2 cytokines. Also, IL-12 production was induced by LPS in TI-mice inoculated with CD4+T cells from spleens of GR-treated normal mice (GR-CD4+T cells, 5x10(6)cells/mouse). Since GR-CD4+T cells have been shown to be antagonistic cells against production of type 2 cytokines by burn-associated type 2 T cells, these results indicate that IL-12 unresponsiveness shown in TI-mice is recovered by GR through the regulation of burn-associated type 2 T cell responses.
Adoptive Transfer↗
Immobilization of cycloisomaltooligosaccharide glucanotransferase for the production of cycloisomaltooligosaccharides from dextran.
Immobilization of cycloisomaltooligosaccharide glucanotransferase (CITase) and its application in the production of cycloisomaltooligosaccharides (CIs) from dextran were studied. Among various carrier materials examined, the enzyme adsorbed physically on Chitopearl BCW-3505 showed the highest activity (1.75 U/ml carrier). The activity remaining was 35%. The maximum CI yield in batch reactions at 0.2, 2 and 10% dextran was 28, 24 and 12%, respectively. The maximum CI yield at 2% dextran (24%) was slightly less than that with the free enzyme under the same conditions (26%). The concentration of linear oligosaccharides, the byproducts in the reaction mixture, was greater with the immobilized CITase than the free enzyme. The immobilized CITase was less thermostable than the free enzyme by about 10 degrees C. The pattern of influence of Ca(2+) concentration on the thermostability differed between the free and immobilized CITase. A Ca(2+) concentration of 50-100 mM was optimum for the thermostability of the immobilized CITase, 10-50 mM for the free enzyme. CIs were produced continuously by a column system packed with the immobilized enzyme at 40 degrees C with a space velocity (SV) of 6 h(-1). The three quarters life time was 4 weeks. We think that relatively long life time at fast SV was accomplished and CI production cost by this method should be lower than the batch reaction. This is the first report on immobilization of CITase.
Journal Article↗
Development of rigor mortis is not affected by muscle volume.
There is a hypothesis suggesting that rigor mortis progresses more rapidly in small muscles than in large muscles. We measured rigor mortis as tension determined isometrically in rat musculus erector spinae that had been cut into muscle bundles of various volumes. The muscle volume did not influence either the progress or the resolution of rigor mortis, which contradicts the hypothesis. Differences in pre-rigor load on the muscles influenced the onset and resolution of rigor mortis in a few pairs of samples, but did not influence the time taken for rigor mortis to reach its full extent after death. Moreover, the progress of rigor mortis in this muscle was biphasic; this may reflect the early rigor of red muscle fibres and the late rigor of white muscle fibres.
Animals↗
Differentiation in chronic myelogenous leukemia cell K562 by spongean sesterterpene.
Scalarane-type sesterterpenes, PHC-1-PHC-7, which have been isolated from a marine sponge, increased hemoglobin production in human chronic myelogenous leukemia cell line K562 at the concentration of 0.1-5 microg/ml. PHC-1, the major constituent, induced the expression of glycophorin A and the enucleation for K562 cells. These sesterterpenes were found to induce erythroid differentiation in K562 cells. In addition, PHC-1 induced G1 arrest of the cell cycle of K562 cells.
Animals↗