Search PubMed⌕ Search

Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 379 records · Page 21Linked to original sources
PubMed1998

Inhibition in a microgravity environment of the recovery of Escherichia coli cells damaged by heavy ion beams during the NASDA ISS phase I program of NASA Shuttle/Mir mission no. 6.

We participated in a space experiment, part of the National Space Development Agency of Japan (NASDA) Phase I Space Radiation Environment Measurement Program, conducted during the National Aeronautics and Space Administration (NASA) Shuttle/Mir Mission No. 6 (S/MM-6) project. The aim of our study was to investigate the effects of microgravity on the DNA repair processes of living organisms in the in orbit. Heavy ion beam radiation- or ç-irradiation-damaged biological samples of Escherichia coli and the radioresistant bacterium Deinococcus radiodurans were prepared and placed in a biospecimen box, which was loaded into the RRMD III sensor unit of the Space Shuttle. Two identical sets of samples were left in the Spacehab's Payload Processing Facility (SPPF) in Florida, USA, as a control. (flight No. STS-84) was launched from NASA John F. Kennedy Space Center (KSC) in Florida, USA, on May 15, 1997. The mission duration was 9.22 days. An astronaut activated the biological samples in the biospecimen box in the Spacehab during orbit in order to start repair of the DNA damaged by heavy ion beams or ç-irradiation and the samples were incubated for 19 h 35 min at about 22ûC, the cabin temperature. The control specimens in the SPPF were subjected to the same treatment under terrestrial gravity. After returned to earth, we investigated cell recovery by comparing the repair of the radiation-damaged DNA of E. coli and D. radiodurans in the microgravity environment in space with that on Earth. The results indicated that the DNA repair process of E. coli, but not of D. radiodurans, cells was inhibited in a microgravity environment.

Cell Survival↗
PubMed1998

Total structures of colistin minor components.

Structural characterization of the colistin (CL) components were carried out using Frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS), tandem mass spectrometry (MS/MS) and the amino acid analysis proposed by MARFEY, and the total structures of 4 minor components including the absolute configuration of the constituent amino acids were proposed. The structures of the minor components were the same as those of the main component colistin A or B except that L-leucine is replaced by L-valine or L-isoleucine.

Anti-Bacterial Agents↗
PubMed1998

K1115 A, a new anthraquinone derivative that inhibits the binding of activator protein-1 (AP-1) to its recognition sites. I. Biological activities.

K1115 A, a new anthraquinone derivative, was isolated from the culture broth of Streptomyces griseorubiginosus (Mer-K1115). K1115A inhibited the direct binding of activator protein-1 (AP-1) to AP-1 oligonucleotide (IC50 = 100 microM), and the production of collagenase in IL-1 alpha-stimulated rat synovial cells (IC50 = 60 microM). In vivo, the application of K1115 A decreased phorbol myristate acetate (PMA)-induced mouse ornithine decarboxylase (ODC) activity. These results indicated that K1115 A is able to attenuate the inflammatory response mediated by AP-1.

Animals↗
PubMed1998

A new anti-MRSA antibiotic complex, WAP-8294A. I. Taxonomy, isolation and biological activities.

WAP-8294A, produced by Lysobacter sp., is a complex consisting of water soluble depsipeptide antibiotics. It was further purified by column chromatographies and HPLC, and 19 components were obtained. WAP-8294A2, a major component, and minor components A1, A4, Ax8, Ax9 and Ax13 were active against gram-positive bacteria, in particular, methicillin-resistant Staphylococcus aureus (MRSA) in vitro. WAP-8294A2 was highly active in vivo in mice against the systemic infection of MRSA.

Animals↗
PubMed1998

Increased expression of interleukin-6 and tumor necrosis factor-alpha in pathologic biliary epithelial cells: in situ and culture study.

We examined the pathologic significance of the expression of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), both proinflammatory cytokines, on intrahepatic biliary epithelial cells, using immunohistochemical and in situ hybridization techniques as well as culture study. IL-6 and TNF-alpha were expressed in the cytoplasm of biliary epithelial cells of damaged small bile ducts and bile ductules, particularly in primary biliary cirrhosis. Their expression on the bile ducts was mild to moderate in other hepatobiliary diseases and mild or absent in normal livers. Signals of IL-6 mRNA and TNF-alpha mRNA were detected in the cytoplasm of biliary epithelial cells, especially in primary biliary cirrhosis. Immunoelectron microscopic study supported this. TNF receptor and to a lesser degree IL-6 receptor alpha-chain were detected on these damaged bile ducts, suggesting an autocrine effect. By Western blotting and enzyme-linked immunosorbent assay, IL-6 and TNF-alpha were frequently detected in gallbladder bile from primary biliary cirrhosis, and their titers were higher compared with other hepatobiliary diseases. Culture of intrahepatic biliary epithelial cells revealed that they expressed IL-6 and secreted IL-6 in the culture media. These results suggest that the intrahepatic biliary epithelial cells are able to synthesize IL-6 and probably TNF-alpha and are involved in the production of bile duct lesions by means of receptor-mediated processes, particularly biliary epithelial proliferation and destruction and autoimmune augmentation, in primary biliary cirrhosis.

Bile↗
PubMed1998

Clinical significance of serum P53 antibody in patients with gastric cancer.

The presence of serum p53 antibody has been reported to have prognostic significance in patients with breast and ovarian cancers. In order to clarify clinical and prognostic significance of p53 antibody in serum, we measured p53 antibody in patients with gastric cancer. Twenty-five patients with gastric cancer were examined as well as 9 patients with gastric polyp as controls. Eight of 25 patients (32%) with gastric cancer were positive for p53 antibody, while no patients with gastric polyp were positive in gastric polyp group (p < 0.05). The presence of p53 antibody was significantly associated with histology, liver metastasis and stage classification in gastric cancer (p < 0.05, respectively). Presence of liver metastasis, type of histology and presence of p53 antibody are independent prognostic factors (p < 0.05, respectively). The overall survival in patients with p53 antibody was significantly shorter survival than for those without antibody (p < 0.05%). These data suggest that p53 antibody serves as one of the prognostic factors in gastric cancer.

Adenoma↗
PubMed1998

[Combined hepatic resection and removal of portal vein tumor thrombi].

Portal thrombectomy with extended hepatectomy for extensively progressive primary liver cancer (Vp 3), in which the tumor thrombus has spread beyond the first portal branches, will make other non-surgical treatments possible and improve patients quality of life. We have performed extensive resections in 15 cases of such Vp 3 liver cancer. One patient with huge HCC involving retrohepatic IVC underwent in situ extended left hepatectomy without reconstruction of IVC, resulting in postoperative renal failure because of thrombosis in the bilateral renal veins, but 14 other patients' postoperative courses were uneventful. Ten of 14 patients relapsed within one year, but these patients underwent non-surgical treatments, resulting in improvement in the quality of life. The 1-, and 3-year survival rates were 55.6% and 32.5%, respectively.

Adult↗
PubMed1997

Molding a peptide into an RNA site by in vivo peptide evolution.

Short peptides corresponding to the arginine-rich domains of several RNA-binding proteins are able to bind to their specific RNA sites with high affinities and specificities. In the case of the HIV-1 Rev-Rev response element (RRE) complex, the peptide forms a single alpha-helix that binds deeply in a widened, distorted RNA major groove and makes a substantial set of base-specific and backbone contacts. Using a reporter system based on antitermination by the bacteriophage lambda N protein, it has been possible to identify novel arginine-rich peptides from combinatorial libraries that recognize the RRE with affinities and specificities similar to Rev but that appear to bind in nonhelical conformations. Here we have used codon-based mutagenesis to evolve one of these peptides, RSG-1, into an even tighter binder. After two rounds of evolution, RSG-1.2 bound the RRE with 7-fold higher affinity and 15-fold higher specificity than the wild-type Rev peptide, and in vitro competition experiments show that RSG-1.2 completely displaces the intact Rev protein from the RRE at low peptide concentrations. By fusing RRE-binding peptides to the activation domain of HIV-1 Tat, we show that the peptides can deliver Tat to the RRE site and activate transcription in mammalian cells, and more importantly, that the fusion proteins can inhibit the activity of Rev in chloramphenicol acetyltransferase reporter assays. The evolved peptides contain proline and glutamic acid mutations near the middle of their sequences and, despite the presence of a proline, show partial alpha-helix formation in the absence of RNA. These directed evolution experiments illustrate how readily complex peptide structures can be evolved within the context of an RNA framework, perhaps reflecting how early protein structures evolved in an "RNA world."

Amino Acid Sequence↗
PubMed1997

Influence of right ventricular volume and pressure overloads on assessment of left ventricular volume using two-dimensional echocardiography in infants and children with congenital heart diseases.

In patients with right ventricular volume or pressure overload, the biplane Simpson's rule underestimates left ventricular volume more than the modified Simpson's rule. We suggest that the modified Simpson's rule should be used for estimation of left ventricular volumes rather than the biplane Simpson's rule in determining therapy for infants or children with complicated congenital heart disease.

Adolescent↗
PubMed1997

Effects of apo E deficiency on plasma lipid levels in mice lacking APOBEC-1.

Apolipoprotein (apo) B100 mRNA undergoes site specific C to U editing, generating a stop-translation codon of apo B48 in the small intestine. This reaction is catalyzed in an editosome which contains APOBEC-1, a catalytic subunit. To clarify the functional significance of the apo B mRNA editing in lipoprotein metabolism, we have generated APOBEC-1 knockout mice and double knockout mice which are deficient in both APOBEC-1 and apo E. The apo B mRNA editing activity was markedly reduced and complete elimination of apo B48 from the plasma was observed in APOBEC-1(-/-) mice. Plasma triglyceride levels significantly increased in the double knockout mice (APOBEC-1(-/-);apo E(-/-)) as compared to apo E(-/-) mice. These results suggest that APOBEC-1(-/-) mice are a valuable model for experiments designed to understand a role of apo B mRNA editing.

APOBEC-1 Deaminase↗
PubMed1997

Bcl-2 protein inhibits oxysterol-induced apoptosis through suppressing CPP32-mediated pathway.

Oxysterols are presumed to mediate cytotoxicity of oxidized LDL in atherosclerotic lesions. To elucidate its molecular mechanism, we established murine macrophage-like P388-D1 cells which over-express Bcl-2 protein by retrovirus-mediated gene transfer. Oxysterols (7-ketocholesterol, 25-hydroxycholesterol) induced nuclear condensation and oligonucleosomal DNA fragmentation, which were partially inhibited by Bcl-2 over-expression. Though CPP32 inhibitor suppressed the cell death in control cells, it showed no additive protection in the cells over-expressing Bcl-2. These findings indicate that oxysterols induce apoptosis via Bcl-2-inhibitable and -uninhibitable pathways, and the former depends on CPP32 activation.

Animals↗
PubMed1997

Improvement of chemical analysis of antibiotics. XXIII. Identification of residual tetracyclines in bovine tissues by electrospray high-performance liquid chromatography-tandem mass spectrometry.

To reliably identify the residual tetracycline antibiotics (TCs), oxytetracycline (OTC), tetracycline, chlortetracycline (CTC) and doxycycline (DC), in bovine tissues, we have established a confirmation method using electrospray ionization liquid chromatography-tandem mass spectrometry (ESI LC-MS-MS) with daughter ion scan. All TCs gave [M+H-NH3]+ and [M+H-NH3-H2O]+ as the product ions, except for DC when [M+H]+ was selected as the precursor ion. The combination of C18 cartridge clean-up and the present ESI LC-MS-MS method can reliably identify TCs fortified at a concentration of 0.1 ppm in bovine tissues, including liver, kidney and muscle, and has been successfully applied to the identification of residual OTC in bovine liver and residual CTC in bovine muscle samples previously found at concentrations of 0.58 ppm and 0.38 ppm by LC, respectively.

Animals↗
PubMed1997

Changes in right ventricular volume in early human neonates.

To evaluate changes in the right ventricular volume in early human neonates, twenty fullterm infants were examined at 2, 24 and 120 h of age by two-dimensional echocardiography. End-diastolic and end-systolic right ventricular volumes (RVEDV and RVESV, respectively) were calculated with a computer system based on the bi-plane Simpson's rule using the apical four chamber and parasternal short axis views. Then right ventricular stroke volume (RVSV), ejection fraction (RVEF), and the mean normalized systolic ejection rate were obtained. The inner diameter of the ductus arteriosus was also measured simultaneously. RVEDV increased significantly by 24 h of age, but remained constant thereafter. RVESV remained virtually unchanged from 2 to 120 h, resulting in a significant increase (36%) of RVSV at 24 h compared with that at 2 h. The mean normalized systolic ejection rate remained unchanged. There was a good correlation between RVEDV and RVSV (r = 0.83). All ductus arteriosus except three narrow ones was closed by 24 h of age. In conclusion, at 24 h of age, the significantly increased RVEDV was closely related to the increased RVSV, which might be induced by increased volume load to the right ventricle because of the closure of the ductus arteriosus.

Ductus Arteriosus↗
PubMed1997

Proteolysis of ankyrin and Na+/K(+)-ATPase in postmortem rat brain: is calpain involved?

Ankyrin links the fodrin-based cytoskeleton to membrane proteins such as Na+/K(+)-ATPase, thereby maintaining cellular integrity. Immunoblotting by antibody raised against erythrocyte ankyrin demonstrated the proteolysis of ankyrin, which was highly correlated with postmortem interval (0-24 h). Proteolysis in the postmortem brain generated the 160-kDa fragment with an identical size as the fragment formed after in vitro proteolysis by calpain. Although microM Ca2+ induced the proteolysis in the homogenate, the presence of mu-calpain was not demonstrated by immunoblotting using the antibody that reacts with large subunits both of mu- and m-calpains. Na+/K(+)-ATPase was also proteolyzed in the postmortem brain.

Animals↗