Biography:

In the past Kazuhiro Aoki has collaborated on articles with Mutsumi Sugita and Motonari Ogawara. One of their most recent publications is Regular paperStructural characterization of a novel glycoinositolphospholipid from the parasitic nematode, Ascaris suum. Which was published in journal Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism.

More information about Kazuhiro Aoki research including statistics on their citations can be found on their Copernicus Academic profile page.

Kazuhiro Aoki's Articles: (20)

Regular paperStructural characterization of a novel glycoinositolphospholipid from the parasitic nematode, Ascaris suum

AbstractA novel glycosphingolipid containing inositol phosphate as an acidic group has been demonstrated in whole tissues of the porcine roundworm, Ascaris suum. The thin layer chromatographic pattern of the total acidic glycolipid revealed the presence of several components, of which a major component (named AGL) with positive reactions toward both orcinol-sulfuric acid (sugar) and molybdate (phosphate) spray reagents was isolated and purified by the use of successive column chromatography on DEAE-Sephadex and silicic acid (latrobeads). From structural studies including compositional sugar analysis, hydrogen fluoride degradation, methylation analysis, periodate oxidation, proton magnetic resonance spectroscopy and fast atom bombardment mass spectrometry, the structure of AGL was deduced to be Galα1–2Ins(1 →)-P-Cer. Aliphatic constituents were lignoceric acid and its 2-hydroxy homologue as the principal fatty acids, and octadecasphinganine and branched heptadecasphinganine as the major sphingoids.

Regular paperStructural characterization of a novel glycoinositolphospholipid from the parasitic nematode, Ascaris suum

AbstractA novel glycosphingolipid containing inositol phosphate as an acidic group has been demonstrated in whole tissues of the porcine roundworm, Ascaris suum. The thin layer chromatographic pattern of the total acidic glycolipid revealed the presence of several components, of which a major component (named AGL) with positive reactions toward both orcinol-sulfuric acid (sugar) and molybdate (phosphate) spray reagents was isolated and purified by the use of successive column chromatography on DEAE-Sephadex and silicic acid (latrobeads). From structural studies including compositional sugar analysis, hydrogen fluoride degradation, methylation analysis, periodate oxidation, proton magnetic resonance spectroscopy and fast atom bombardment mass spectrometry, the structure of AGL was deduced to be Galα1–2Ins(1 →)-P-Cer. Aliphatic constituents were lignoceric acid and its 2-hydroxy homologue as the principal fatty acids, and octadecasphinganine and branched heptadecasphinganine as the major sphingoids.

Regular paperStructural characterization of a novel glycoinositolphospholipid from the parasitic nematode, Ascaris suum

AbstractA novel glycosphingolipid containing inositol phosphate as an acidic group has been demonstrated in whole tissues of the porcine roundworm, Ascaris suum. The thin layer chromatographic pattern of the total acidic glycolipid revealed the presence of several components, of which a major component (named AGL) with positive reactions toward both orcinol-sulfuric acid (sugar) and molybdate (phosphate) spray reagents was isolated and purified by the use of successive column chromatography on DEAE-Sephadex and silicic acid (latrobeads). From structural studies including compositional sugar analysis, hydrogen fluoride degradation, methylation analysis, periodate oxidation, proton magnetic resonance spectroscopy and fast atom bombardment mass spectrometry, the structure of AGL was deduced to be Galα1–2Ins(1 →)-P-Cer. Aliphatic constituents were lignoceric acid and its 2-hydroxy homologue as the principal fatty acids, and octadecasphinganine and branched heptadecasphinganine as the major sphingoids.

Effect of ascorbic acid deficiency on primary and reparative dentinogenesis in non-ascorbate-synthesizing ods rats

AbstractAscorbic acid is essential to the biosynthesis of collagen, the major organic matrix component of dentine. The ODS rat is a mutant strain of Wistar rat characterized by hereditary lack of l-gulono-gamma-lactone oxidase and thus is unable to synthesize ascorbic acid. ODS rats were given an ascorbic acid-free diet to investigate how ascorbic acid deficiency affects dentine formation in vivo. Histomorphometric analysis on their growing molars and incisors showed a significant reduction in both size and mineral apposition rate of dentine, as revealed by contact microradiography and fluorescent time-marking, respectively. A similar reduction in bone formation was simultaneously demonstrated in the mandible, confirming the previously reported osteopathic effects of ascorbic acid deficiency. When pulp inflammation was induced in lower first molars by making unsealed pulp exposures, specimens from control animals showed continuous deposition of an osteodentine-like tissue in the radicular pulp chamber; this type of mineralized tissue formation was greatly reduced in ascorbic acid-deprived animals. These results indicate that ascorbic acid deficiency hampers dentine formation under both physiological and pathological conditions of the dentine/pulp complex. ODS rats could be useful in investigating in vivo effects of ascorbic acid deficiency on the formation of dentine and other dental mineralized tissues.

Endocrine pharmacologyPeptide-induced de novo bone formation after tooth extraction prevents alveolar bone loss in a murine tooth extraction model

AbstractTooth extraction causes bone resorption of the alveolar bone volume. Although recombinant human bone morphogenetic protein 2 (rhBMP-2) markedly promotes de novo bone formation after tooth extraction, the application of high-dose rhBMP-2 may induce side effects, such as swelling, seroma, and an increased cancer risk. Therefore, reduction of the necessary dose of rhBMP-2 which can still obtain sufficient bone mass is necessary by developing a new osteogenic reagent. Recently, we showed that the systemic administration of OP3-4 peptide, which was originally designed as a bone resorption inhibitor, had osteogenic ability both in vitro and in vivo. This study evaluated the ability of the local application of OP3-4 peptide to promote bone formation in a murine tooth extraction model with a very low-dose of BMP. The mandibular incisor was extracted from 10-week-old C57BL6/J male mice and a gelatin hydrogel containing rhBMP-2 with or without OP3-4 peptide (BMP/OP3-4) was applied to the socket of the incisor. Bone formation inside the socket was examined radiologically and histologically at 21 days after the extraction. The BMP/OP3-4-group showed significant bone formation inside the mandibular extraction socket compared to the gelatin-hydrogel-carrier-control group or rhBMP-2-applied group. The BMP/OP3-4-applied mice showed a lower reduction of alveolar bone and fewer osteoclast numbers, suggesting that the newly formed bone inside the socket may prevent resorption of the cortical bone around the extraction socket. Our data revealed that OP3-4 peptide promotes BMP-mediated bone formation inside the extraction socket of mandibular bone, resulting in preservation from the loss of alveolar bone.

Variability of factors driving spatial and temporal dispersion in river plume and Chattonella antiqua bloom in the Yatsushiro Sea, Japan

Highlights•The Chattonella antiqua blooms initially formed in the northern area of the Yatsushiro Sea.•The blooms were triggered in the riverine water advection in the southern area.•The southward advection was determined by the wind stress and pressure gradient.

Basic ResearchPhytic Acid: An Alternative Root Canal Chelating Agent

Highlights•A new naturally occurring chelating agent (phytic acid, IP6) was tested.•We tested the ability of IP6 in removing the smear layer.•We examined IP6 effect on viability and ALP activity of osteoblast-like cells.•IP6 effectively removed smear layer and was biocompatible to the used cells.

Factors controlling the spatio-temporal distribution of the 2009 Chattonella antiqua bloom in the Yatsushiro Sea, Japan

AbstractA harmful bloom due to the raphidophycean flagellate, Chattonella antiqua, was found in the Yatsushiro Sea, western Kyushu, Japan, from the end of July to the beginning of August 2009. The bloom resulted in enormous economic damage to cultured finfish production in aquaculture farms concentrated in the southwestern area. To investigate the factors controlling the spatio-temporal distribution of the bloom, data analysis and numerical simulations were conducted using field monitoring data and a three-dimensional hydrodynamic model coupled to a Lagrangian particle-tracking model. Results of the monitoring data analysis showed that the initial development of the C. antiqua bloom occurred in Kusuura Bay and the northeastern area near the mouth of the Kuma River, and subsequently the bloom expanded rapidly to the whole area. The simulation results indicated that the source region of the widespread bloom was not Kusuura Bay but the northeastern area. The southwestward evolution of the bloom was primarily controlled by the passive transport due to the surface residual current driven by fresh water discharge from the Kuma River and northeasterly winds. On the favorable conditions of river discharge and wind, the massive bloom of C. antiqua that formed in the northeastern area was quickly transported southwestward within a few days.

Research papersA numerical study of the Kuroshio-induced circulation in Tosa Bay, off the southern coast of Japan

AbstractWe performed a numerical experiment for the circulation in Tosa Bay using a triply-nested 1/50-degree model. This study revisits the climatological features of the Kuroshio-induced circulation in Tosa Bay by comparison with previous studies based on hydrographic observations. The model well reproduces the climatological features previously reported and reveals the following new findings: long-term mean circulation in Tosa Bay is characterized by an anticlockwise circulation (AC) spreading over the bay. The AC exhibits a cold-dome structure with deep baroclinic velocity shears. The velocity shears can be accounted for mainly by geostrophic shear. In this regard, however, the gradient wind balance is maintained because an ageostrophic velocity attributed to the momentum advection is caused by the state where the AC is intensified. The primary condition for controlling the development and decay of the AC is the mesoscale onshore–offshore movement of the Kuroshio axis; the secondary condition is a high-frequency submesoscale variation such as a Kuroshio frontal wave, which can be regarded as noise for the primary condition. Sequential development and decay of the AC is frequently simulated when the Kuroshio takes a nearshore path, and the frontal waves propagate eastward and interact with coastal water in Tosa Bay. That is, the horizontal advection of relative vorticity due to the frontal wave propagation plays an important role in controlling the sequential response.

Homografts of the Tympanic Membrane With Malleus; Histological Study In Cat

The present experiments on cats were performed to explore the process of survival and take of transplanted homografts of tympanic membrane with malleus, the homografts being respectively preserved in 4 % and 0.5 % formalin (pH 7.0) solutions, and to explore the reaction of middle ear mucosa of the recipient. The present study also included gross and histopathological examinations of the eardrum and observation of fibers of the lamina propria of the transplanted tympanic membrane by means of polarizing microscopy and of vascularization by intravascular India ink injection. The experiments conducted using a total of 96 cats yielded results leading to the following conclusions.1) After six months the transplanted tympanic membrane showed nearly normal histologic features, with a fibrous layer between the lining epithelial and thin mucosal layers. The middle ear mucosa also became thinner and was covered with ciliated epithelium at this stage. 2) As regards vascular distribution, most vessels entered from the peripheral regions to become distributed all over the eardrum with mutual anastomoses. 3) Fibrous tissues of the lamina propria of the pars tensa of the transplanted eardrum remained intact over the six month period. 4) The transplanted malleus was neither destroyed not absorbed, and proved to survive well with active vascularization. 5) The microscopic changes observed in the middle ear mucous membrane of the recipient showed non-specific reactions to Gelfoam. The grafts were not subjected to immunological rejection. Homograft thus offer the best grafting material, but seemed to show poor resistance to infection.

Bacterial Examination of Serous Otitis Media and Experimental Tubal Stenosis

Involvement of bacteria in serous otitis media was studied in man and by animal experimentation (using rabbits). Bacteria from the middle ear fluid, the skin of the external ear canal and the epipharynx of 100 human ears were cultured. Bacteria were also cultured from 50 ears of rabbits with serous otitis media induced experimentally by tubal stenosis, in the same way as those taken from human ears. Bacteria were detected in the middle ear fluid of 61 human ears (61%), in 48 human ears (48%) except for those with contamination. The bacteria detected in the middle ear fluid were the same as those detected in the epipharynx in 40 of the 50 rabbit ears during the period from the start of treatment to the 30th day. In ears which were treated for more than 30 days, the bacteria detected in the middle ear fluid tended not to be the same as those detected in the epipharynx. From these results it was inferred that inflammation of the epipharynx spread over the middle ear cavity through the auditory tube.

A Study in Children on the Inhibited Pneumatization of the Mastoid in Otitis Media with Effusion

We investigated the development of mastoid air cells in cases of otitis media with effusion (OME) contracted during the fastgrowth period of childhood. It was considered that, if a comparative study of these cases against subjects in normal health was conducted on what types of effects of chronic inflammation of the middle ear in a child has on the development of the mastoid air cells from the time of onset until adulthood, it might reveal a major clue to the causal relationship between chronic inflammatory conditions of the middle ear and inhibited pneumatization of the temporal bone.

Recessive GM3 synthase deficiency: Natural history, biochemistry, and therapeutic frontier

AbstractGM3 synthase, encoded by ST3GAL5, initiates synthesis of all downstream cerebral gangliosides. Here, we present biochemical, functional, and natural history data from 50 individuals homozygous for a pathogenic ST3GAL5 c.862C>T founder allele (median age 8.1, range 0.7–30.5 years). GM3 and its derivatives were undetectable in plasma. Weight and head circumference were normal at birth and mean Apgar scores were 7.7 ± 2.0 (1 min) and 8.9 ± 0.5 (5 min). Somatic growth failure, progressive microcephaly, global developmental delay, visual inattentiveness, and dyskinetic movements developed within a few months of life. Infantile-onset epileptic encephalopathy was characterized by a slow, disorganized, high-voltage background, poor state transitions, absent posterior rhythm, and spike trains from multiple independent cortical foci; >90% of electrographic seizures were clinically silent. Hearing loss affected cochlea and central auditory pathways and 76% of children tested failed the newborn hearing screen. Development stagnated early in life; only 13 (26%) patients sat independently (median age 30 months), three (6%) learned to crawl, and none achieved reciprocal communication. Incessant irritability, often accompanied by insomnia, began during infancy and contributed to high parental stress. Despite catastrophic neurological dysfunction, neuroimaging showed only subtle or no destructive changes into late childhood and hospitalizations were surprisingly rare (0.2 per patient per year). Median survival was 23.5 years. Our observations corroborate findings from transgenic mice which indicate that gangliosides might have a limited role in embryonic neurodevelopment but become vital for postnatal brain growth and function. These results have critical implications for the design and implementation of ganglioside restitution therapies.

ArticleStochastic ERK Activation Induced by Noise and Cell-to-Cell Propagation Regulates Cell Density-Dependent Proliferation

Highlights•FRET imaging reveals stochastic ERK activity pulses in vitro and in vivo•Frequency of ERK activity correlates with density-dependent proliferation rate•Synthetic ERK activity oscillation induces an increase in proliferation rate•SRF is involved in ERK activity dynamics-dependent gene expression

Full paperThe intra-articular injection of RANKL-binding peptides inhibits cartilage degeneration in a murine model of osteoarthritis

AbstractWe recently found that the receptor activator of NF-κB ligand (RANKL)-binding peptide, OP3-4 stimulated the differentiation of both chondrocytes and osteoblasts. OP3-4 is also shown to inhibit cartilage degeneration. To clarify whether the peptide can inhibit cartilage degeneration without stimulating bone formation, we first performed a proliferation assay using C3H10T1/2 (the murine mesenchymal stem cell line), which is the common origin of both chondrocytes and osteoblasts. The RANKL-binding peptides, OP3-4 and W9, promoted cellular proliferation at 24 and 48 h, respectively. Next, we injected both peptides into the intra-articular space of the knee joints of mice with monosodium-iodoacetate (MIA)-induced osteoarthritis to clarify the effects of the peptides on cartilage tissue. Twenty-five nine-week-old male C57BL/6J mice received injections of vehicle, or the same molar amount of W9, OP3-4, or a control peptide (which could not stimulate osteoblast differentiation) on days 7, 14, and 21 after the injection of MIA. The mice were sacrificed on day 28. The histomorphometric analyses revealed that both peptides inhibited the degeneration of cartilage without enhancing bone formation activity. Our data suggest that the stimulation of mesenchymal cell proliferation by the RANKL-binding peptides might lead to the inhibition of cartilage degeneration.

Applications and the Future of Peptide Drugs for Inflammatory Bone Resorption

AbstractRecently, peptides have been used as an option for rational drug design. We focus on the peptide antagonist, WP9QY (W9) peptide, which was originally designed to mimic the critical binding site of a tumor necrosis factor (TNF) α on TNF receptor type 1 using a molecular modeling technique. Here, the inhibitory effect of the W9 peptide on inflammatory bone resorption is reviewed, including its peptide delivery system, which could be a tool for overcoming the aggregation problem of peptide drugs in clinical applications.

The Effects of NF-κB Inhibitors on Bone Formation

AbstractThe transcription factor nuclear factor-κB (NF-κB) plays a pivotal role in the regulation of the immune system, including the inflammatory response. The NF-κB signaling pathways also play an important role in bone homeostasis, especially in regard to osteoclast differentiation. The role of NF-κB in bone formation, however, remains to be fully elucidated. In this review, the effects of NF-κB inhibitors, focusing on bone formation, are described based on our findings.

ArticleGTP Hydrolysis by the Rho Family GTPase TC10 Promotes Exocytic Vesicle Fusion

SummaryTC10, a Rho family GTPase, has been shown to play an important role in the exocytosis of GLUT4 and other proteins, primarily by tethering the vesicles at the plasma membrane. Using a newly developed probe based on fluorescence resonance energy transfer, we found that TC10 activity at tethered vesicles dropped immediately before vesicle fusion in HeLa cells stimulated with epidermal growth factor (EGF), suggesting that GTP hydrolysis by TC10 is a critical step in vesicle fusion. In support of this model, a GTPase-deficient TC10 mutant potently inhibited EGF-induced vesicular fusion in HeLa cells and depolarization-induced neuronal secretion. Furthermore, we found that GTP hydrolysis by TC10 in the vicinity of the plasma membrane was dependent on Rac and the redox-regulated Rho GAP, p190RhoGAP-A. We propose that an EGF-stimulated GAP accelerates GTP hydrolysis of TC10, thereby promoting vesicle fusion.

ArticleCell-to-Cell Heterogeneity in p38-Mediated Cross-Inhibition of JNK Causes Stochastic Cell Death

Highlights•A multiplexed live-cell imaging system visualizes suppression of JNK by p38 kinase•Cross-inhibition of JNK by p38 generates cell-to-cell heterogeneity in JNK activity•p38-induced DUSP1 expression is inversely correlated with JNK activity in single cells•Heterogeneity in JNK activity is associated with fractional killing upon UV stress

Regional distinctions in cortical bone mineral density measured by pQCT can predict alterations in material property at the tibial diaphysis of the Cynomolgus monkey

AbstractWe examined whether regional differences in cortical bone mineral density (Ct.BMD) measured by peripheral quantitative computed tomography is related to the heterogeneity of bone tissue and whether regional Ct.BMD is a better indicator of changes in bone material properties. Bilateral tibiae were obtained from 17 female adult Cynomolgus monkeys (Macaca fascicularis; mean age 16.8 years). After determining that Ct.BMD was similar between the right and left tibiae, the left tibiae were used for bone histomorphometry and the right for a three-point bending test. The Ct.BMD in the posterior quadrant was significantly higher than that in the anterior quadrant. In the bone histomorphometric analysis, all parameters (i.e., average osteonal area, average osteonal bone area, osteon population density, percent osteonal area [%On.Ar], percent osteonal bone area [%On.B.Ar], percent osteonal area of initial remodeling [%Il.On.Ar], percent osteonal area of secondary remodeling [%Sd.On.Ar], porosity, and percent osteoid area in the posterior region) were significantly lower than those in the anterior region. The results indicated that in the same cross-section, bone tissue structure was heterogeneous. Both total- and posterior-Ct.BMD were positively correlated with breaking stress and negatively correlated with toughness, whereas anterior-Ct.BMD was positively correlated with elastic modulus. Backward stepwise multiple regression analyses indicated that posterior-Ct.BMD and total-Ct.BMD were the best variables for predicting breaking stress and toughness, respectively, when age is taken into account. The %On.Ar, %On.B.Ar, and %Il.On.Ar in the posterior region were negatively correlated with elastic modulus. The %On.Ar, %On.B.Ar, and %Sd.On.Ar in the posterior region were positively correlated with toughness. These findings indicated that regional Ct.BMD measurement is useful to assess changes in the material properties of bone associated with the degree of mineralization. In particular, anterior-, posterior-, and total-Ct.BMD can be used separately to predict changes in the material properties of the tibial diaphysis.

Advertisement
Join Copernicus Academic and get access to over 12 million papers authored by 7+ million academics.
Join for free!

Contact us