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T Aoki

Publications and source records attributed to T Aoki.

At least 1,387 records · Page 77Linked to original sources
PubMedDate not supplied

Synthesis of antibiotic-loaded interporous hydroxyapatite blocks by vacuum method and in vitro drug release testing.

Interporous hydroxyapatite ceramic (Ca10(PO4)6(OH)2) has excellent bio-compatibility and interlinked pore structure, antibiotics could be loaded into pores in vacuum system. To confirm penetration of the agent to the HAb (2 cm3 cubic block), the aminoglycoside antibiotic (Isepamicin Sulfate; ISP) dissolved in eosin dye at various vacuum pressures. In ISP slow release study, the blocks were placed in 5 ml of PBS at a temperature of 37 degrees C. The PBS was replaced every 48 h and samples containing released ISP were stored until assay. All were found to release the drug maintaining a mean concentration of 0.41 microg ml(-1) even after 18 days of nine exchanges. This concentration of antibiotic exceeded the minimum inhibitory concentration against the common causative organisms of osteomyelitis. The results suggest that HAb impregnated with antibiotics using a simple vacuum system may serve as a valuable new method of administering local chemotherapy, primarily when used as a strut graft for bone defects.

Anti-Bacterial Agents↗
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Expression of Japanese flounder c-type lysozyme cDNA in insect cells.

Lysozyme is a widely distributed hydrolase which likely plays an important role in bio-defense systems. In the current study, we constructed a baculovirus expression system for the c-type lysozyme cDNA of Japanese flounder (Paralichthys olivaceus) and evaluated the activity of the recombinant protein. This activity was estimated, by turbidimetric assay, to be 7.7U/mg, a value five times higher than that of hen egg white (HEW) c-type lysozyme examined under the same conditions. The optimum pH and temperature for the lytic activity of the Japanese flounder c-type recombinant lysozyme were found to be 5.0-6.5 and 40 degrees C, respectively. Two groupings for fish lysozyme activity are proposed; the first has an optimum pH of approximately 6.0 and the second an optimum pH of above 8.0. Flounder c-type lysozyme was found to possess little lytic activities against Edwardsiella tarda and Streptococcus sp. This latter characteristic may help explain the fact that these two bacterial species are responsible for significant disease problems in cultured Japanese flounder.

Animals↗
PubMedDate not supplied

Temperature-responsive bioconjugates. 1. Synthesis of temperature-responsive oligomers with reactive end groups and their coupling to biomolecules.

Using 3-mercaptopropionic acid (MPA) as a chain-transfer agent, the radical oligomerization of N-isopropylacrylamie (IPAAm) was carried out with varying molar ratios of MPA to IPAAm and DMF. The molecular weight of oligo-IPAAm (OIPAAm) could be controlled by the ratio of MPA to IPAAm. The OIPAAm was confirmed to average one carboxyl end group per chain. All OIPAAms samples were highly water-soluble at lower temperatures and exhibited phase separation near 32 degrees C. The optical transmittance of the OIPAAms aqueous solutions changed drastically at 32 degrees C which was independent of OIPAAms molecular weight. In aqueous solutions of OIPAAm having concentrations higher than 1 wt% and molecular weight of 6100, the oligomers were precipitated and recovered in 85 wt% yield of their original content. Further, OIPAAm was grafted to atelo collagen by activated ester-amine coupling. The OIPAAm-collagen conjugates were able to dissolved in cold water and precipitated at 34 degrees C. Temperature-responsive OIPAAm-collagen conjugates are expected to maintain native collagen functionality in the solution state, react at lower temperatures, and be easily removed from the system with small temperature increases.

3-Mercaptopropionic Acid↗
PubMedDate not supplied

Temperature-responsive bioconjugates. 2. Molecular design for temperature-modulated bioseparations.

We have synthesized carboxyl semitelechelic oligo(N-isopropylacrylamide) (OIPAAm) using radical telomerization with 3-mercaptopropionic acid. This telomerization is also effective for the synthesis of carboxyl semitelechelic co-oligomers of IPAAm with butyl methacrylate (BMA) as hydrophobic or N,N-dimethylacrylamide (DMAAm) as hydrophilic comonomers. All co-oligomers are highly water-soluble at lower temperatures and exhibit phase separation with increasing temperature. Pure OIPAAm exhibits a lower critical solution temperature (LCST) at 32 degrees C, and the LCST for co-oligomers can be controlled to increase over 32 degrees C with increasing DMAAm composition and to decrease below 32 degrees C with increasing BMA composition. OIPAAm was grafted to bovine serum albumin (BSA) and bovine plasma fibrinogen (BPF) by activated ester-amine coupling. These OIPAAm-biomolecule conjugates maintain their temperature responses, are soluble in cold water, and precipitate over a range of temperatures related to oligomer content. Conjugates could be selectively precipitated and independently separated from conjugate solution mixtures with increasing temperature. In this case, the number of OIPAAm molecules attached to a conjugate affects the aggregate sizes of precipitated conjugates in mixtures. Both conjugate mixture ratios and solution concentrations influence the contamination of oligo(IPAAm-co-DMAAm)-BSA conjugates in precipitated oligo(IPAAm-co-BMA)-BPF conjugates. Furthermore, precipitated conjugates separated using centrifugation and filtration redissolve in water and maintain their biofunctionality, indicating the potential of strategy in reversible bioreactors and protein separations.

3-Mercaptopropionic Acid↗
PubMedDate not supplied

Temperature-responsive bioconjugates. 3. Antibody-poly (N-isopropylacrylamide) conjugates for temperature-modulated precipitations and affinity bioseparations.

Immunoglobulin G (IgG) has been modified by poly(N-isopropylacrylamide) (PIPAAm) to create a novel bioconjugate which exhibits reversible phase transition behavior at 32 degrees C in aqueous media. A terminal carboxyl group introduced into PIPAAm molecule by polymerization of IPAAm with 3-mercaptopropionic acid was used for conjugation to IgG via coupling reaction of activated ester with protein amino group. These conjugates exhibited rapid response to changes in solution temperature and significant phase separation above a critical solution temperature corresponding to that for the original PIPAAm. These conjugates bound to antigen quantitatively in aqueous system, and antigen-bound complex also demonstrated phase separation and precipitation above a critical temperature. Precipitate was reversibly redissolved in cold buffer. Though particular conjugate which includes 12 molecules of PIPAAm with 6,100 molecular weight suppressed more than 95% of Fc-dependent binding with protein A, it retained approximately 60% of original specific antigen binding activity. It was manifested that polymer content of conjugate was 20-30 wt% for the case of 6,100 molecular weight of PIPAAm to demonstrate specific antigen binding activity most effectively and to reduce Fc-dependent binding with protein A. IgG-PIPAAm conjugates were soluble in water and formed antigen-bound complex in homogeneous solution system below a critical temperature. These conjugates were separated from solution and other solutes corresponding to PIPAAm nature and scarcely bound to antigen above a critical temperature. It is revealed that temperature-responsive PIPAAm conjugated to biomolecule operated as a switching molecule. These phenomena are attractive for not only reversible bioreactors and protein separations but also carrier substrate to localize biomolecules such as drugs, peptides and hormones in a living body.

3-Mercaptopropionic Acid↗
PubMedDate not supplied

Effect of molecular architecture of poly(N-isopropylacrylamide)-trypsin conjugates on their solution and enzymatic properties.

Polymer-enzyme hybrid conjugates modified by a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm), have been synthesized. We have investigated the molecular architecture of PIPAAm-enzyme conjugates by preparing two types of PIPAAm-trypsin conjugates, wherein PIPAAm chains are attached by either single-end or multipoint chemistry. A semitelechelic co-oligomer (IDc) was attached to trypsin by single-point conjugation (IDc-trypsin). A copolymer (PIDAAc) consisting of acrylic acid and IPAAm randomly linked in polymer chains was attached to trypsin using multipoint conjugation (PIDAAc-trypsin). Both conjugates exhibited reversible temperature-responsive phase separation. The IDc-trypsin conjugate exhibited phase separation at the same temperature as pure IDc, due to the highly mobile free polymer end group which remains sensitive to small temperature changes. The PIDAAc-trypsin conjugate precipitated at higher temperatures than pure PIDAAc, whose movement was restricted by multiple binding points. Enzyme stability in solution was improved after introduction of PIPAAm chains, which prevented autolysis attributed to conjugate steric hindrance. Stability under repeated temperature cycling was also dependent on the architecture of conjugates; the IDc-trypsin conjugate was more stable than the PIDAAc-trypsin. As a consequence, single-end conjugation of polymer to enzyme provides novel bioconjugate with novel functionality attributed to attached polymer while retaining native biological function with high stability.

Acrylic Resins↗
PubMedDate not supplied

Interferon-alpha therapy for chronic active Epstein-Barr virus infection: potential effect on the development of T-lymphoproliferative disease.

PURPOSE: A patient with aggressive chronic active Epstein-Barr virus (CAEBV) infection is described whose disease activity subsided after interferon (IFN)-alpha therapy. PATIENT AND METHODS: The patient had intermittent fever, cytopenia, liver dysfunction, hepatosplenomegaly, abnormal titers of EBV-associated antibodies, and positive EBV genomes. RESULTS: Despite repeated trials of the antiviral agents prednisolone and gamma-globulin, his condition deteriorated. The administration of IFN-alpha (1 x 10(5) U/kg subcutaneously 3 times per week) led to a dramatic clinical improvement. During the IFN-alpha therapy, the rearrangement bands of T-cell antigen receptor genes disappeared assessed by Southern blotting with a decrease in the number of activated T cells, although the EBV-genome remained evident. CONCLUSIONS: These observations suggest that IFN-alpha is useful in managing CAEBV, possibly restraining the clonal development of T-lymphoproliferative disease (LPD) and EBV-associated B-LPD, although it does not eradicate the proliferation of EBV.

Antiviral Agents↗
PubMedDate not supplied

Phylogenetic relationships among microsporidia based on rDNA sequence data, with particular reference to fish-infecting Microsporidium balbiani 1884 species.

Recently, large discrepancies have been identified between microsporidian systematics based on molecular and traditional characteristics. In the current study the 530f-580r region of the rRNA gene of eight microsporidian species was cloned and sequenced. Included were two unclassified species of Microsporidium Balbiani, 1884 and an unidentified microsporidian that infects the musculature of different sea bream species. Sequence identities in excess of 98% indicated that these three species almost certainly are members of the same genus. Phylogenetic analyses of all microsporidian sequence data available for this region of the gene (20 species) and for partial small subunit sequences (51 species of 21 genera) revealed these species to be distinct from the family Pleistophoridae Doflein, 1901 and closely related them to the genus Sproguea Weissenberg, 1976. This clade was found to comprise a sister taxon to that containing the vast majority of fish-infecting species. Broad cladistic divisions were found between terrestrial insect-infecting and fish-infecting species, which together are distant from the aquatic insect-infecting microsporidia. The rRNA gene of certain fish-infecting genera was found to be more highly conserved than previously reported. This has implications for its utility in diagnostic assays and phylogenetic studies at, or close to, the species level.

Animals↗
PubMedDate not supplied

Drug interaction effects on antitumour drugs (XV): Disulfiram as protective agent against cyclophosphamide-induced urotoxicity without compromising antitumour activity in mice.

The prevention of cyclophosphamide-induced urotoxicity by disulfiram was studied in mice. A single dose of cyclophosphamide (100-400 mg/kg, intraperitoneally) produced a significant dose-dependent increase in urinary bladder weight within 48 hr of treatment. Disulfiram prevented cyclophosphamide-induced bladder damage in a dose-dependent manner in mice when orally administered simultaneously with antitumour agents, but failed to diminish the acute toxicity, leukocytotoxicity and immunotoxicity of cyclophosphamide. The protective effect of disulfiram on the bladder was critically dependent on administration timing. Oral administration of disulfiram between 60 min. before and 60 min. after the injection of cyclophosphamide was found to be effective. The optimum time was simultaneous administration of both drugs. Diethyldithiocarbamate and carbon disulfide, metabolites of disulfiram, prevented cyclophosphamide-induced bladder damage when administered simultaneously with cyclophosphamide 1 to, 3 or 5 hr afterwards. Disulfiram slightly potentiated the antitumour activity of cyclophosphamide against Sarcoma 180 or EL-4 leukaemia in vivo when administered simultaneously with cyclophosphamide. In contrast, diethyldithiocarbamate or carbon disulfide did not interfere with cyclophosphamide antitumour activity when administered 3 hr after cyclophosphamide. From these preliminary studies, disulfiram appears to be a likely candidate for protection against cyclophosphamide-induced urotoxicity without compromising the therapeutic utility of the alkylating agent.

Administration, Oral↗
PubMedDate not supplied

KP-1 is a marker for extraneuronal neurofibrillary tangles and senile plaques in Alzheimer diseased brains.

KP-1 immunostaining with microwave pretreatment in formalin-fixed, paraffin-embedded sections enhanced its immunoreactivity revealing extraneuronal neurofibrillary tangles (NFTs) called ghost tangles, senile plaques (SPs) and perivascular deposits as well as microglial labelling in Alzheimer-diseased brains. KP-1 stained cored and uncored SPs, granules within the SPs, perivascular beta-amyloid protein (beta AP) and star-like beta AP deposits in cortical layer I, which was confirmed in comparison to silver-impregnated structures in the Reusche-stained or Gallyas-Schiff-stained sections. On double immunostaining with KP-1 and ubiquitin, ghost tangles were labelled by KP-1 and intraneuronal NFTs were positive for ubiquitin. A few KP-1-positive granules deposits different from amyloid core were found within the SPs and the outer margin of amyloid cores of SPs were stained by KP-1. KP-1-positive microglia were attached to the ubiquitin-positive intraneuronal NFTs. Microglia were more numerously labelled by CR3/43 than by KP-1, and CR3/43-positive microglia were found to be preferentially attached to SPs. As KP-1 recognizes lysosome-associated antigen CD68, similarities between KP-1 positivity and Reusche-stained structures suggested that lysosomal activity was associated with beta AP deposits and ghost tangles were involved in lysosome-associated processes. It is speculated that lysosomes play a role in the process of ghost tangle formation and in beta AP deposits leading to SP formation.

Aged↗
PubMedDate not supplied

Elevation of serum albumin levels in nagase analbuminemic rats by allogeneic bone marrow cell transplantation.

We investigated the feasibility of correcting the congenital absence of albumin in Nagase analbuminemic rats (NARs) by allogeneic bone marrow cell transplantation (BMT). Seven-week-old male NARs were used as recipients, and 6- to 8-week-old male Sprague-Dawley (SD) rats were used as allograft donors. NARs were divided into three groups: a BMT group (n=10) in which bone marrow cells were infused into the liver; a hepatocyte transplantation (HCT) group (n=8) in which hepatocytes were transplanted into the liver, and a control group (n=8) in which PBS was injected into the portal vein. Serum albumin levels were measured as an indicator of the function of the grafted cells, and the phenotypic characteristics of the engrafted cells in the recipient's liver were assessed with immunohistochemical and immunofluorescence techniques. At 8 weeks after cell transplantation, the serum albumin levels of the BMT group and HCT group were significantly higher than in the control group. The hepatocyte-like cells derived from bone marrow cells expressed albumin in liver of the NARs. According to this result, bone marrow cells can differentiate into hepatocyte-like cells in vivo. The results show that BMT is an effective treatment for congenital analbuminemia in a rat model and suggest that allogeneic BMT can be used as an efficient therapy for hereditary metabolic diseases.

Acetylglucosaminidase↗
PubMedDate not supplied

Neutrophil elastase inhibitor ameliorates reperfusion injury in a canine model of lung transplantation.

BACKGROUND: We investigated the effects of neutrophil elastase inhibitor ONO-5046 Na on lung ischemia-reperfusion injury in a canine model of single lung transplantation. METHODS: 24 mongrel dogs, 12 donors and 12 recipients, were used for single lung transplantation. Lung grafts were preserved for 18 h by cold ischemia then transplanted into the left thoracic cavity of recipients. In 6 recipients (ONO group), a bolus of ONO-5046 Na (10 mg/kg) was introduced before reperfusion and followed by continuous infusion (10 mg/kg/h). The remaining 6 recipients (control group) did not receive ONO-5046 Na and thus served as controls. We evaluated lung function and respiratory parameters over 240 min. RESULTS: The total cell number in bronchoalveolar lavage fluid increased significantly in the control group in comparison to that in the ONO group. Histologic scores after 4 h of reperfusion and myeloperoxidase activity were significantly lower in the ONO group than in the control group. CONCLUSION: Neutrophil elastase inhibitor ONO-5046 Na may be useful in ameliorating lung reperfusion injury after transplantation.

Animals↗
PubMedDate not supplied

Non-Alzheimer dementia with status spongiosus and neuronal cell loss showing unusual perineuronal structures and point mutation at 129 codon of prion protein.

The subject presented with intellectual decline followed by progressive muscle weakness of the bilateral upper limbs when he was 60 years old. He had a point mutation (methionin-valine) at 129 prion protein codon. He died at the age of 63 and necropsy revealed bilateral frontal lobe atrophy. The frontal cortex showed neuronal cell loss in layers II and III with spongiform change. Reusche silver impregnation technique for beta-peptide combined with ubiquitin immunostaining revealed perineuronal structures encircling degenerated neurons and ubiquitin-immunoreactive (IR) dot-like deposits. They were distributed particularly in the temporal neocortex and entorhinal cortex. They differed from either classic senile or diffuse plaque by the absence of amyloid core in the center and of amyloid fibrils. Ubiquitin-IR materials were also found as neuronal inclusions in the hippocampal granular cells. Nigral degeneration and neuronal loss in the hypoglossal nerve nucleus and in the anterior horn of the spinal cord were also found and spinal cord motoneurons had Bunina body inclusions. The clinical features and pathological findings were consistent with non-Alzheimer dementia with status spongiosus and neuronal cell loss. The unusual perineuronal structures found in our case might be a specific cellular pathology of dementia of the frontal lobe type.

Cell Death↗
PubMedDate not supplied

Borrelia burgdorferi-seropositive chronic encephalomyelopathy: Lyme neuroborreliosis? An autopsied report.

A 36-year-old Japanese woman presented with progressive cerebellar signs and mental deterioration of subacute course after her return from the USA. Her serum antibody to spirochete Borrelia burgdorferi was significantly elevated. A necropsy 4 years after her initial neurological signs revealed multifocal inflammatory change in the cerebral cortex, thalamus, superior colliculus, dentate nucleus, inferior olivary nucleus and spinal cord. The lesions showed spongiform change, neuronal cell loss, astrocytosis and proliferation of activated microglial cells. The internal capsule was partially vacuolated and the spinal cord, notably at the thoracic level, was demyelinated and cavitated in the lateral funiculus. Microglial cells aggregated within and around the spongiform lesions and microglial nodules were present in the medulla oblongata. Use of Warthin-Starry stain demonstrated silver-impregnated organisms strongly suggesting B. burgdorferi in the central nervous tissues. The dentate nucleus and inferior olivary nucleus showed the most advanced lesions with profound fibrillary gliosis. Occlusive vascular change was relatively mild, and fibrous thickening of the leptomeninges with lymphocyte infiltrates was localized in the basal midbrain. The ataxic symptoms were due to the dentate and olivary nucleus lesions and mental deterioration was attributable to the cortical and thalamic lesions. Spongiform change, neuronal cell loss, and microglial activation are characteristic pathological features in the present case. The cerebellar ataxia and subsequent mental deterioration are unusual clinical features of Lyme neuroborreliosis. Spirochete B. burgdorferi can cause focal inflammatory parenchymal change in the central nervous tissues and the present case may be an encephalitic form of Lyme neuroborreliosis.

Adult↗
PubMedDate not supplied

Age-related changes in nerve growth factor receptor immunoreactive neurons in the magnocellular basal forebrain system in rat brain--an immunocytochemical and morphometric study.

Morphometrical changes with aging in nerve growth factor receptor (NGFR) immunoreactive neurons in the basal forebrain were studied in juvenile and aged rat brains by means of NGFR immunohistochemistry. The nucleus basalis of Meynert (NBM) had cell loss and atrophy of NGFR immunoreactive neurons, and the horizontal nucleus of diagonal band of Broca (HNDB) showed only atrophy of these neurons. The medial septal nucleus and vertical nucleus of diagonal band of Broca had no significant change. Neuropil NGFR immunostaining was reduced in its intensity in the aged rats. As nerve growth factor is synthesized in the target areas and retrogradely transported to the nerve cell body within the basal forebrain and NGFR immunoreactive neurons are largely cholinergic ones, degeneration of NGFR-positive neurons in the basal forebrain may be related to a decreased cholinergic activity. The degeneration of the dendrites of NGFR-immunoreactive neurons were reported to be extensively found in the basal forebrain nuclei, in contrast, degeneration of the cell body of NGFR-immunoreactive neurons was confined to those in the NBM and HNDB in the present study. These findings suggest that atrophic changes in the dendrites precede those in the cell bodies of NGFR-immunoreactive neurons.

Aging↗
PubMedDate not supplied

Criterion-related validity of diagnostic criteria for alexithymia in a general hospital psychiatric setting.

BACKGROUND: The diagnostic criteria for alexithymia (DCA) was proposed by Fava et al. in 1995. The purpose of this study was to examine the criterion-related validity of the DCA in a general hospital psychiatric setting. METHODS: The subjects included 126 outpatients with psychiatric disturbance. The severity of alexithymic characteristics was assessed using the DCA and Beth Israel Hospital Psychosomatic Questionnaire (BIQ). Two Japanese versions of the 26-item Toronto Alexithymia Scale (TAS-26) and Minnesota Multiphasic. Personality Inventory-2 (MMPI-2) were administered. RESULTS: The DCA had relatively high sensitivity and specificity, indicating adequate discriminant validity. The discriminant validity of the DCA was also supported by significant associations of the DCA with the TAS-26 and MMPI-2. These results indicate that when used for screening, the DCA has adequate criterion-related validity. CONCLUSIONS: The DCA may be clinically useful in a general hospital psychiatric setting.

Adolescent↗