Search PubMed⌕ Search

Biomedical subjects

H Murakami

Publications and source records attributed to H Murakami.

At least 145 records · Page 8Linked to original sources
PubMed2000

Transfructosylation of thiol group by beta-fructofuranosidases.

Beta-fructofuranosidase fructosylated not only the hydroxyl group but also the thiol group of 2-mercaptoethanol in a transfer reaction using sucrose as a donor substrate. The enzymes from Candida utilis and Saccharomyces cerevisiae (bakers' yeast) were effective catalysts for the thio-fructofuranosylation. The thio-fructosylation product was isolated by activated carbon chromatography and its structure was confirmed by Fab-mass spectrometry and NMR spectroscopy. The thio-fructofuranoside was synthesized effectively at around 3.0 M for the acceptor concentration. The product increased with the sucrose concentration at least up to 1.9 M. O-Fructofuranoside was simultaneously synthesized at an early stage of the reaction, although it was hydrolyzed on further incubation. On the contrary, the thio-fructofuranoside accumulated efficiently after synthesis, indicating it was very stable against the hydrolytic action of the beta-fructofranosidase.

Carbohydrate Conformation↗
PubMed2000

Synthesis of novel heterobranched beta-cyclodextrins from alpha-D-mannosylmaltotriose and beta-cyclodextrin by the reverse action of pullulanase, and isolation and characterization of the products.

Alpha-D-mannosyl-maltotriose (Man-G3) were synthesized from methyl alpha-mannoside and maltotriose by the transfer action of alpha-mannosidase. (Man-G3)-betaCD and (Man-G3)2-betaCD were produced in about 20% and 4% yield, respectively when Aerobacter aerogenes pullulanase (160 units per 1 g of Man-G3) was incubated with the mixture of 1.6 M Man-G3 and 0.16 M betaCD at 50 degrees C for 4 days. The reaction products, (Man-G3)-betaCD were separated to three peaks by HPLC analysis on a YMC-PACK A-323-3 column and (Man-G3)2-betaCD were separated to several peaks by HPLC analysis on a Daisopak ODS column. The major product of (Man-G3)-betaCDs was identified as 6-O-alpha-(6(3)-O-alpha-D-mannosylmaltotriosyl)-betaCD by FAB-MS and NMR spectroscopies. The structures of (Man-G3)2-betaCDs were analyzed by TOF-MS and NMR spectroscopies, and confirmed by comparison of elution profiles of their hydrolyzates by alpha-mannosidase and glucoamylase on a graphitized carbon column with those of the authentic di-glucosyl-betaCDs. The structures of three main components of (Man-G3)2-betaCDs were identified as 6(1),6(2)-, 6(1),6(3)- and 6(1),64-di-O-(63-O-alpha-D-mannosyl-maltotriosyl)-betaCD.

Cyclodextrins↗
PubMed2000

Forensic study of sex determination using PCR on teeth samples.

In this study, sex determination using polymerase chain reaction (PCR) on tooth material was evaluated from the viewpoint of forensic medicine. The sensitivity of PCR for detection of the Y chromosome-specific alphoid repeat sequence and the X chromosome-specific alphoid repeat sequence was 0.5 pg of genomic DNA. Sex could be determined by PCR of DNA extracted from the pulp of 16 freshly extracted permanent teeth and dentine including the surface of the pulp cavity of 6 freshly extracted milk teeth. Sex could be determined using the pulp in all 20 teeth (10 male and 10 female) preserved at room temperature for 22 years. For the pulp of teeth stored in sea water, the sex could be determined in all 8 teeth immersed for 1 week and in 5 of 6 teeth immersed for 4 weeks. In the remaining 1 tooth, in which sex determination based on the pulp failed, the sex could be determined correctly when DNA extracted from the tooth hard tissue was examined. For teeth stored in soil, the sex could be determined accurately in all 8 teeth buried for 1 week, 7 of 8 teeth buried for 4 weeks, and in all 6 teeth buried for 8 weeks. When teeth were heated for 30 min, sex determination from the pulp was possible in all teeth heated to 100, 150, and 200 degrees C, and even in some teeth heated to 250 degrees C. When this method was applied to actual forensic cases, the sex of a mummified body estimated to have been discovered half a year to 1 year after death could be determined readily by examination of the dental pulp. In the skeletons of 2 bodies placed under water for approximately 1 year and approximately 11 years and 7 months, pulp tissues had been dissolved and lost, but sex determination was possible using DNA extracted from hard dental tissues. These results indicate that this method is useful in forensic practices for sex determination based on teeth samples.

Adult↗
PubMed2000

Activation of protein kinase C induces internalization of the GABA(C) receptors expressed in Xenopus oocytes.

In a previous study, we showed that the protein kinase C (PKC) activator 4beta-phorbol 12-myristate 13-acetate (PMA) inhibited the gamma-aminobutyric acid (GABA)-gated currents in Xenopus oocytes expressing human rho1 GABA(C) receptors. To investigate whether the inhibition of currents was due to a decrease in efficacy or in the potency of rho1 GABA(C) receptor, concentration-response curves for GABA were compared before and after PMA treatment. The EC50 concentrations of GABA obtained during the maximally inhibited period were not statistically different from the concentrations obtained before PMA treatment (1.74 +/- 0.33 and 1.45 +/- 0.28 microM, respectively). These results indicate that the inhibition depends on a change in number or conductance of active receptor channels, but not on a change in affinity for GABA. To allow histochemical detection of rho1 GABA(C) receptors, we constructed a receptor tagged at the C-terminal position with human c-myc epitope. Electrophysiologically, the tagged receptors showed almost the same sensitivities for GABA and PMA as those of wild-type rho1 GABA(C) receptors. Immunohistochemistry with anti-myc antibody detected a dense concentration of tagged receptors at the surface area of Xenopus oocytes. Transient exposure to PMA reduced the density of immunofluorescence at the surface area and increased it in the subsurface area. These results suggest that the stimulation of protein kinase C leads to internalization of rho1 GABA(C) receptors expressed in Xenopus oocytes.

Animals↗
PubMed2000

Spontaneous occlusion of ruptured vertebral artery dissection at the extradural fenestration associated with extradural origin of the posterior inferior cerebellar artery--case report.

A 69-year-old female suffered from sudden onset of severe headache. Computed tomography showed subarachnoid hemorrhage primarily located in the posterior fossa. Initial angiography demonstrated a fenestration of the vertebral artery and an extracranial origin of the posterior inferior cerebellar artery. However, no bleeding points could be clearly detected. The operative findings revealed a massive clot in subarachnoid space, but no bleeding point. Serial angiography demonstrated dissection in one of the limbs of the fenestrated vertebral artery on the 25th day after the onset. On the 100th day, the lesion was spontaneously occluded. The patient is presently doing well at 8 years after surgery.

Aged↗
PubMed2000

Ulnar neuropathy caused by a lipoma in Guyon's canal--case report.

A 74-year-old female presented with a 3-month history of compression neuropathy of the right ulnar nerve in Guyon's canal. Magnetic resonance imaging and ultrasonography revealed the location of the mass lesion. Surgical exploration discovered a lipoma pressing against both the ulnar nerve and the ulnar artery. The mass was extirpated. The postoperative course was uneventful with good function recovery.

Aged↗
PubMed2000

[In vitro activities of carbapenem antibiotics against the various clinical isolates].

The annual changes of antibacterial activities of beta-lactam antibiotics, mainly carbapenem antibiotics, were investigated against 5 bacterial species, S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, which had been isolated from the clinical materials at Toho University Omori Hospital during the period of 1995 to 1997. In addition, antibacterial activities against other main bacterial strains isolated from the clinical materials during 1997 were also determined. The five bacterial species on which annual changes of the sensitivity were investigated did not show any remarkable trend to increase in resistance to the carbapenem antibiotics tested. The antibacterial activities of the carbapenem antibiotics against MRSA were weak, and MIC90 values were between 25 and 50 micrograms/ml. In S. marcescens and P. aeruginosa on which high resistance by the production of metallo-beta-lactamase has become a problem in recent years, there were no remarkable changes in annual changes of sensitivities. Especially, MIC90 valuses of the carbapenem antibiotics against P. aeruginosa were between 12.5 and 25 micrograms/ml, 4 to 8 times better than that of PIPC, like the case of CAZ. Furthermore, the carbapenem antibiotics showed strong antibacterial activities against clinically important 16 bacterial species, from Gram-positive to Gram-negative bacteria.

Carbapenems↗
PubMed2000

Pathological findings of tissue reactivity of gelatin resorcin formalin glue: an autopsy case report of the repair of ventricular septal perforation.

A seventy-three-year-old man was treated for ventricular septal perforation with Gelatin Resorcin Formalin (GRF) glue. The patient died of multiple organ failure 36 days after the surgery. In autopsy, macroscopically, the inferior wall was reconstructed successfully by the GRF glue. Furthermore, microscopic study revealed the excellent growth of collagen and elastic fiber where the GRF was glued. No infiltration of inflammatory cells was evident. There have been no reports that the safety and efficacy of GRF glue was pathologically proven in an autopsy case.

Aged↗
PubMed2000

[A case of acupuncture needle dermatitis].

A 65-year-old female visited our clinic with painful red vesicular dermatitis of the forehead and around the left eye. She had received acupuncture for headache and shoulder stiffness 6 days before visiting our clinic. A patch test with nickel sulfate gave positive results. We treated her with the greater occipital nerve block and trigger point injection which relieved her pain. We reached the diagnosis of greater occipital trigeminal syndrome with contact dermatitis from the acupuncture needle.

Acupuncture Therapy↗
PubMed2000

[The strategy of combination phase I/II study].

Combination chemotherapy plays an important role in anticancer chemotherapy. Many new anticancer drugs, including target-based drugs, have been introduced clinically. The opportunity to evaluate combination chemotherapy including new drugs has increased recently. Combination phase I/II studies must be designed scientifically and ethically in order to evaluate the efficacy and safety of combination chemotherapy including new drugs. It is important to choose appropriate drugs and to determine an effective method of administration, because drug-drug interaction can be a problem in combination chemotherapy. It is important to clarify the causes of drug-drug interactions through pharmacokinetics analysis because these interactions influence toxicity and efficacy. To conduct high quality clinical trials, we need to improve the infrastructure of such trials.

Clinical Trials, Phase I as Topic↗
PubMed2000

Prolonged survival in two cases of T-prolymphocytic leukemias with complex hypodiploid chromosomal abnormalities.

We encountered two cases of T-prolymphocytic leukemias (T-PLL) with complex hypodiploid chromosomal abnormalities. Both cases showed mild organomegaly and marked leukocytosis (144.5 x 10(9)/L, 102.6 x 10(9)/L, respectively). Although both cases developed into refractory progressive diseases at the terminal stage, the oral administration of dexamethasone was very effective for leukocytosis and thrombocytopenia in case 1 and oral cyclophosphamide was effective for reducing elevated leukocytes and the organomegaly in case 2. Despite the poor prognosis of T-PLL, our cases showed that less toxic therapies such as oral dexamethasone or cyclophosphamide may be the treatment of choice for patients with an indolent phase of T-PLL. Our study and previously reported findings suggest that complex hypodiploid chromosomal abnormalities are characteristic in T-PLL.

Aged↗
PubMed1999

Targeted disruption of the gene encoding the proteolipid subunit of mouse vacuolar H(+)-ATPase leads to early embryonic lethality.

Vacuolar H(+)-ATPase (V-ATPase) is responsible for acidification of intracellular compartments in eukaryotic cells. Its 16-kDa subunit (proteolipid, PL16) plays a central role in V-ATPase function, forming the principal channel via which protons are translocated. To elucidate physiological roles of V-ATPase in mammalian cell function and embryogenesis, we attempted to generate a PL16 null mutant mouse by gene-targeting. Mice heterozygous (PL16(+/-)) for the proteolipid mutation were intercrossed and their offspring were classified according to genotype. There were no homozygous (PL16(-/-)) pups among 69 neonates examined, but a few PL16(-/-) embryos were found during the pre-implantation stages of embryonic development, up to day 3.5 post-coitum. These results suggested that PL16 (and hence V-ATPase) may play an essential role in cell proliferation and viability during early embryogenesis. PL16(+/-) mice were indistinguishable from their wild-type littermates and displayed no discernible abnormalities, although the PL16 mRNA level in PL16(+/-) mice decreased to about one-half of wild-type levels.

Animals↗
PubMed1999

Cell wall-affecting antibiotics induce expression of a novel gene, drp35, in Staphylococcus aureus.

A novel gene, drp35, of Staphylococcus aureus, which was inducible especially with cell wall-affecting antibiotics, has been cloned. Analysis of differential hybridization with mRNAs enhanced in the presence of beta-lactams resulted in two positive clones that harbored a new gene encoding a 35,845-Da protein (Drp35) and the penicillin-binding protein 2 (PBP2). Immunoblot analysis revealed that the Drp35 protein band was evidently enhanced after 30 min in the presence of beta-lactams. The Drp35 expression was also enhanced with not only beta-lactams, but also vancomycin, bacitracin, and fosfomycin. Homology search revealed that Drp35 was a new protein. Our results revealed that it was specific in S. aureus and respondent to these agents in both methicillin-resistant and -sensitive strains of S. aureus.

Amino Acid Sequence↗
PubMed1999

Adenovirus-mediated kallikrein gene transfer inhibits neointima formation via increased production of nitric oxide in rat artery.

Tissue kallikrein cleaves kininogen substrate to produce vasoactive kinin peptides that have been implicated to play a role in the proliferation of vascular smooth muscle cells (VSMC). In order to explore potential roles of the kallikrein-kinin system in vascular biology, we evaluated the effects of adenovirus-mediated kallikrein gene delivery on neointima formation in balloon-injured rat artery. Infection of isolated rat aortic segments with adenovirus containing the human tissue kallikrein gene resulted in a time-dependent secretion of recombinant human tissue kallikrein, and significant increases in nitric oxide (NOx) and guanosine 3',5'-cyclic monophosphate (cGMP) levels post gene transfer. Human tissue kallikrein gene was delivered locally via adenoviral vectors into left common carotid artery after balloon angioplasty. Two weeks following gene transfer, we observed a 39% reduction in intima/media ratio at the injured vessel as compared to that of rats receiving control virus (n = 8, P < .01). Delivery of N(omega)-nitro-L-arginine methyl ester (L-NAME), a NOx synthase inhibitor via minipump for 2 weeks, blocked the protective effect and reversed the intima/media ratio to that of control rats (n = 5, P < .01). These results indicated that human tissue kallikrein gene delivery inhibits neointima formation via NO-cGMP signaling pathway. This study provides new insights into the role of the vascular kallikrein-kinin system and may have significant implications for gene therapy in treating occlusive vascular diseases.

Adenoviridae↗
PubMed1999

Preparation of poly(DL-lactide-co-glycolide) nanoparticles by modified spontaneous emulsification solvent diffusion method.

PURPOSE: The objectives of this study were to establish a new preparation method for poly(DL-lactide-co-glycolide) (PLGA) nanoparticles by modifying the spontaneous emulsification solvent diffusion (SESD) method and to elucidate the mechanism of nanoparticle formation on the basis of the phase separation principle of PLGA and poly(vinyl alcohol) (PVA) in the preparation system. METHODS: PLGA nanoparticles were prepared by the modified-SESD method using various solvent systems consisting of two water-miscible organic solvents, in which one solvent has more affinity to PLGA than to PVA and the other has more affinity to PVA than to PLGA. The yield, particle size, size distribution and PVA content of the PLGA nanoparticles were evaluated, and the phase separation behaviors of the polymers were elucidated. RESULTS: The modified-SESD method provided a good yield of PLGA nanoparticles over a wide range of composition ratios in the binary mixture of organic solvents. Several process parameters, including the fed amount of PLGA, PLGA concentration and PVA concentration were examined to achieve the optimum preparation conditions. The discrete powder of PLGA nanoparticles was obtained by freeze-drying. No change in the PVA content of PLGA nanoparticles was observed even after several times of washing treatment by ultrafiltration, suggesting a strong surface adsorption. It was found that the appropriate selections of binary solvent mixtures and polymeric concentrations in both organic and aqueous phases could provide excellent yield and favorable physical properties of PLGA nanoparticles. CONCLUSION: The proposed modified-SESD method can be used to provide PLGA nanoparticles of satisfactory quality at an acceptable yield for industrial purposes.

Diffusion↗
PubMed1999

Meiotic DNA replication checkpoint control in fission yeast.

In eukaryotes, the DNA replication checkpoint prevents entry into mitosis when DNA replication is incomplete and is crucial for maintaining genomic integrity. Much less is known about equivalent controls that operate during meiosis. Here, we show that a DNA replication checkpoint control operates during meiosis in fission yeast. The mitotic checkpoint Rad genes and the Cds1 protein kinase are required for the DNA replication checkpoint during meiosis, with Cds1 playing a more prominent role than it does during mitosis. When DNA replication is blocked, the checkpoint maintains Cdc2 tyrosine 15 phosphorylation keeping Cdc2 protein kinase activity low and preventing onset of meiosis I. Additionally, there is a second checkpoint acting during meiosis that is revealed if cells are prevented from maintaining Cdc2 tyrosine 15 phosphorylation when DNA replication is blocked. Such cells arrest with high Cdc2 protein kinase activity and separated spindle pole bodies, an arrest state similar to that observed in mitotic budding yeast cells when DNA replication is incomplete. This second checkpoint is meiosis specific and may reflect processes occurring only during meiosis such as increased recombination rates, an extended duration of nuclear division, or homolog chromosome pairing.

CDC2 Protein Kinase↗