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Biomedical subjects

Hiroyuki Tanaka

Publications and source records attributed to Hiroyuki Tanaka.

At least 37 records · Page 2Linked to original sources

p21Cip1/WAF1 regulates radial axon growth and enhances motor functional recovery in the injured peripheral nervous system.

Recent studies have provided evidence that p21Cip1/WAF1 has not only cell cycle-associated activities but also other biological activities like neurite elongation. To investigate the role of p21Cip1/WAF1 in the in vivo axonal regeneration in the peripheral nervous system, we developed a p21Cip1/WAF1 knockout (KO) mice sciatic nerve injury model. We performed quantitative assessments of the functional, histological, and electrophysiological recoveries after sciatic nerve injury in p21Cip1/WAF1 KO mice and compared the results with those of the wild-type mice. p21Cip1/WAF1 KO mice showed a significant delay of the motor functional recovery between 21 and 42 days after sciatic nerve injury. The values of motor conduction velocity in p21Cip1/WAF1 KO mice were significantly lower than those in the wild-type mice on postoperative day 28. The mean percent neural tissue and the mean nerve axon width of p21Cip1/WAF1 KO mice were significantly less than those of the wild-type mice, which was caused by hyperphosphorylation of neurofilaments. Therefore, p21Cip1/WAF1 was considered to be involved in radial axon growth and to be essential for the motor functional recovery following peripheral nervous system injury.

Animals↗

A cyclooxygenase-2 inhibitor alters Th1/Th2 cytokine balance and suppresses autoimmune myocarditis in rats.

Acute myocarditis is a clinically serious disease; however, no effective treatment has been elucidated. Cyclooxygenase (COX)-2 is a key factor for progression of inflammation. Although inflammation is an essential pathological feature of acute myocarditis, the role of COX-2 in this process remains unclear. Thus, the purpose of this study was to clarify the role of COX-2 in acute myocarditis. We used a rat experimental autoimmune myocarditis (EAM) model and a specific COX-2 inhibitor in this study. Lewis rats were immunized on day 0 with porcine cardiac myosin to establish EAM. We administered the COX-2 inhibitor (meloxicam, 0.1 mg/kg per day) daily; the rats were killed on day 21. Echocardiograms, body and heart weight, heart rate, blood pressure, and histological and molecular examinations were performed. Cytokine expression in the hearts and cell proliferation against cardiac myosin were also analyzed. The COX-2 inhibition during the immune response (late) phase attenuated EAM development; however, the inhibition during the antigen priming (early) phase did not attenuate EAM. The COX-2 inhibitor altered Th1/Th2 cytokine balance and inhibited cell proliferation in vitro. The COX-2 inhibitor suppresses the development of EAM. COX-2 regulation is promising for treating acute myocarditis.

Animals↗

Sperm-derived sperm motility-initiating substance from amphioxus Branchiostoma belcheri.

The sperm of amphioxus, Branchiostoma belcheri, were immotile when excised from the testis and suspended in seawater. The sperm became motile upon spawning in natural seawater, suggesting mechanisms that triggered sperm motility during spawning. When a male amphioxus that underwent spawning was transferred to a cup containing a small amount of natural seawater, and then the seawater containing the spawned sperm was centrifuged, the supernatant caused motility initiation in the immotile sperm from the testis. This sperm motility-initiating activity was also found in the supernatant of seawater in which immotile sperm from the testis were incubated overnight. These suggest that in the amphioxus, a sperm motility-initiating substance resides in the sperm, and upon spawning, the substance is transformed into a free and active form to activate the sperm. Partial purification of the substance revealed it as a small and heat-stable substance with maximum UV absorbance at 234 nm.

Animals↗

3D kinematic analysis of the acromioclavicular joint during arm abduction using vertically open MRI.

Many researchers have evaluated the motions of the shoulder girdle, especially scapular and humeral motion. However, few reports exist that describe motions of the acromioclavicular joint. The purpose of the present study was to analyze the 3D kinematics of the acromioclavicular joint during arm abduction using 3D MR images obtained by a vertically open MRI. Fourteen shoulders of seven volunteers were examined in seven static positions from 0 degrees to the maximum abduction in a seated position. 3D surface models of the clavicle and scapula were created, and the movements of the acromioclavicular joint from 0 degrees to each position were calculated using the volume-based registration technique. From these calculations, the translations were evaluated and the rotational motions were analyzed using the concept of the screw axis. In the anteroposterior direction, the clavicle translated most posteriorly (-1.9 +/- 1.3 mm) at 90 degrees of abduction and most anteriorly (1.6 +/- 2.7 mm) at maximum abduction. In the superoinferior direction, the clavicle translated slightly superiorly (0.9 +/- 1.9 mm). When analyzing relative motion of the scapula with respect to the clavicle, the scapula generally rotated about a specific screw axis passing through the insertions of both the acromioclavicular and the coracoclavicular ligaments on the coracoid process. The average rotation was 34.9 +/- 8.4 degrees.

Acromioclavicular Joint↗

Physiological comparison of off-pump and on-pump coronary artery bypass grafting in patients on chronic hemodialysis.

OBJECTIVES: Despite the long-term benefit, the operative results of conventional coronary artery bypass grafting for chronic hemodialysis patients remain unsatisfactory. The efficacy of off-pump coronary artery bypass grafting for hemodialysis patients is yet to be determined. The purpose of this study was to investigate the postoperative physiology of off-pump coronary artery bypass grafting for hemodialysis patients. METHODS: Twenty-five hemodialysis cases who underwent isolated coronary artery bypass grafting were reviewed. Fifteen of these patients underwent off-pump coronary artery bypass grafting (off-group) and 10 underwent on-pump coronary artery bypass grafting (on-group). Comparisons were made in cardiac function (cardiac index and stroke volume index), respiratory function (AaDO2), hemodialysis management (blood urea nitrogen, creatinine, right atrial pressure, pulmonary wedge pressure), and bleeding tendency (postoperative blood loss and blood transfusion). RESULTS: There was no operative mortality, but 3 major postoperative complications occurred (2 sternal wound infections in the off-group and 1 pneumonia in the on-group). There was no difference in cardiac index or stroke volume index. AaDO2 was significantly lower in the off-group. Plasma concentrations of blood urea nitrogen and creatinine were similar between groups. Right atrial pressure was lower and pulmonary wedge pressure tended to be lower in the off-group. Postoperative bleeding and blood transfusion were similar between groups. CONCLUSION: Our study confirmed that off-pump coronary artery bypass grafting is feasible for hemodialysis patients. Physiologic data showed that off-pump coronary artery bypass grafting might be effective in preserving postoperative lung oxygenation.

Aged↗

Construction and expression of a single chain Fv fragment against pharmacologically active paeoniflorin in Escherichia coli, and its potential use in an enzyme-linked immunosorbent assay.

A recombinant single chain variable-fragment (scFv) antibody against paeoniflorin (PF) was produced using the hybridoma cell line C31B9. Variable regions of heavy (V (H)) and light (V (L)) chain antibody genes were directly cloned from cDNA resources of hybridoma C31B9 and assembled using splicing by overlap extension (SOE)-PCR using a (Gly (4)Ser) (3) linker DNA. The constructed scFv genes were cloned into pET28a vectors for the generation of recombinant proteins in Escherichia coli. Most of the recombinant proteins were expressed in inclusion bodies. The yield of refolded and purified scFv was 1.89 mg per 100 mL of cell culture. The recombinant scFv displayed cross-reactivity as its mother monoclonal antibody (MAb) C31B9. Therefore, the newly expressed scFv protein was applied to quantitative ELISA to determine the total paeoniflorin (PF) and albiflorin (Alb) concentrations in peony root samples. Using PF as a standard compound, the full linear range of the assay was extended from 0.78 to 25 microg/mL. The results obtained by ELISA employing both the recombinant scFv and the original MAbC31B9 showed a reasonably good agreement with each other.

Antibodies, Monoclonal↗

Primary pulmonary choriocarcinoma combined with adenocarcinoma.

An extremely rare autopsy case of primary pulmonary choriocarcinoma combined with adenocarcinomatous components in a 77-year-old Japanese man is described. The patient died of rapidly progressive respiratory dysfunction without ante-mortem diagnosis. Autopsy revealed necro-hemorrhagic areas of the primary lung tumor with a typical biphasic pattern of choriocarcinoma. Topographical analysis suggested that moderately to poorly differentiated adenocarcinoma components partially surrounded the choriocarcinomatous components. Moreover, dedifferentiated carcinomatous components were scattered next to both adenocarcinomatous and choriocarcinomatous areas, and a few cells of the dedifferentiated carcinomatous components had a similar immunoreaction to conventional adenocarcinomatous or choriocarcinomatous components, such as surfactant apoprotein A, placental alkaline phosphatase or beta-human chorionic gonadotropin. Additionally, epithelial membrane antigen-positive cytotrophoblastic cells were rarely found in choriocarcinomatous areas. The present case suggests that primary lung choriocarcinoma can occur closely related to conventional pulmonary adenocarcinoma, although collision tumor was not completely ruled out.

Adenocarcinoma↗

Synergy of two thermophiles enables decomposition of poly-epsilon-caprolactone under composting conditions.

The ultimate degradation (i.e. complete mineralization) of biodegradable polymers proceeds through hydrolysis to the production of degradation intermediates (primary degradation) that are then taken into the microbial cell and further degraded to CO2 and water. We first isolated thermophilic actinomycete (Streptomyces thermonitrificans PDS-1), which has the activity of ultimate degradability, from compost in which poly-epsilon-caprolactone (PCL) degraded vigorously. We next tried to investigate the detailed mechanisms of degradation of the PCL in compost by developing a new experimental method in which isolated microorganisms are used to inoculate sterilized compost raw materials containing PCL. It was confirmed that the ultimate degradation of PCL could not be achieved by the action of the strain PDS-1 alone, and that a supplementary microorganism (Bacillus licheniformis HA1) isolated from compost utilizes the degradation intermediates and also increases the activity of the other primary microorganism (PDS-1) by adjusting the pH. We could thus show experimental proof of synergy between two thermophiles in the ultimate degradation of a biodegradable polymer in compost.

Bacillus↗

CARM1 regulates proliferation of PC12 cells by methylating HuD.

HuD is an RNA-binding protein that has been shown to induce neuronal differentiation by stabilizing labile mRNAs carrying AU-rich instability elements. Here, we show a novel mechanism of arginine methylation of HuD by coactivator-associated arginine methyltransferase 1 (CARM1) that affected mRNA turnover of p21cip1/waf1 mRNA in PC12 cells. CARM1 specifically methylated HuD in vitro and in vivo and colocalized with HuD in the cytoplasm. Inhibition of HuD methylation by CARM1 knockdown elongated the p21cip1/waf1 mRNA half-life and resulted in a slow growth rate and robust neuritogenesis in response to nerve growth factor (NGF). Methylation-resistant HuD bound more p21cip1/waf1 mRNA than did the wild type, and its overexpression upregulated p21cip1/waf1 protein expression. These results suggested that CARM1-methylated HuD maintains PC12 cells in the proliferative state by committing p21cip1/waf1 mRNA to its decay system. Since the methylated population of HuD was reduced in NGF-treated PC12 cells, downregulation of HuD methylation is a possible pathway through which NGF induces differentiation of PC12 cells.

Animals↗

Pharmacokinetic study of ginsenosides Rb1 and Rg1 in rat by ELISA using anti-ginsenosides Rb1 and Rg1 monoclonal antibodies.

Enzyme-linked immunosorbent assay (ELISA) systems using anti-ginsenoside Rb1 (G-Rb1) and Rg1 (G-Rg1) monoclonal antibodies (MAbs) were established for pharmacokinetic investigations of G-Rb1 and G-Rg1 in rat serum. The systems not only allowed sensitive detection of G-Rb1 at the level as low as 20 ng/ml and of G-Rg1 at 300 ng/ml, but showed strong capacity for detecting the two agents in a broad concentration range (20 to 400 ng/ml for G-Rb1 and 0.3 to 10 microg/ml for G-Rg1, respectively). In this respect, these assay systems are superior to other methods using thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). In addition, another advantage of these immunoassays is the comparably low quantities of specimen required; as little as 5 microl of serum suffices the need for determination of ginsenosides. We report in this article the application of this immunoassay in pharmacokinetic study of G-Rb1.

Animals↗

[Synthesis and optical properties of the helical oligonaphthalenes].

We have developed an efficient synthesis method for optically active oligonaphthalenes (from 2 mer to 16 mer), which are connected at their 1,4-positions, under oxidative homo coupling with a stoichiometric amount of CuCl(2) and amines. The absolute configuration of the newly formed axis bond was determined based on the CD spectra of oligonaphthalenes with 1) two pyrene rings on the central naphthalenes or 2) two tetraphenylporphyrins (TPP) on the top and bottom naphthalenes. The fluorescence quantum yields increased as the number of naphthalene units increased in methoxy derivatives 10-12, and the intramolecular energy transfer quantum yields of bispyrene derivatives 7-9 were around 20% regardless of the number of naphthalene units. Furthermore, the hexadecanaphthalene derivative 4b with two TPPs exhibited a clear exciton coupling over an interchromophore distance to ca. 66 A.

Amines↗

Atomic force microscopic observation of Escherichia coli ribosomes in solution.

Ribosomes of Escherichia coli were visualized in buffer solution by atomic force microscopy (AFM). A series of time-dependent AFM images showed that ribosomes spontaneously adsorb on mica. Although ribosomes observed in air are forced to flatten on the surface, the height of ribosomal particles obtained under a physiological buffer solution is 21.8+/-0.5 nm, which is consistent with the ideal diameter. We succeeded in observing single ribosomes in a near-native condition.

Escherichia coli↗

Clinical characteristics, etiologies and pathophysiology of patients with severe short stature with severe GH deficiency: questionnaire study on the data registered with the foundation for growth science, Japan.

In this study, we sent questionnaires to doctors treating severe short stature with severe GH deficiency (GHD) (height SDS (HtSDS) below -4 and all peak GH to provocative stimuli below 2 micro/L) (abbreviated as Severe Case), and obtained effective replies of 51 cases. The clinical characteristics, etiologies, and pathophysiology of these patients were examined. Among the 51 Severe Cases no consanguinity was observed, 44 were IGHD (24 males and 20 females), 3 were GH-1 gene deletion, 2 were Pit-1 gene mutation, and 2 were achondroplasia. HtSDS in these Severe Cases was already remarkably low at 12 (-3.0) and 24 months old (-3.9), while their birth weight and birth length were within normal ranges. Among 44 patients with IGHD, 12 were isolated GHD, and the remaining 32 were combined pituitary hormone deficiency (CPHD). Pituitary MRI was undergone in 25 idiopathic GHD, and abnormal findings (pituitary atrophy, interruption of stalk, and ectopic posterior lobe) were observed in 21 patients with CPHD. More than half of these patients had the history of breech delivery. Three patients with GH-1 gene mutation showed normal pituitary MRI, whereas one of two patients with Pit-1 mutation showed pituitary atrophy and narrowing of pituitary stalk. In conclusion, Severe Cases tended to have CPHD, and the incidence of Severe Case was only 0.6% of total IGHD. Although GHD due to genetic disorders is considered to be extremely rare (0.06% of total IGHD), the incidence reaches high levels (9.8%) among Severe Cases. Growth disorders in these Severe Cases seem to occur soon after delivery. Much earlier diagnosis and hGH treatment are desirable to attain better final height in the Severe Cases. GH-1 and Pit-1 gene analyses are crucial, when genetic abnormalities other than achondroplasia are suspected.

Achondroplasia↗

Effects of salmeterol xinafoate and fluticasone propionate on immunological activation of human cultured mast cells.

BACKGROUND: The clinical efficacy of combination therapy comprising a long acting beta(2)-agonist (LABA) and corticosteroid is widely recognized for the treatment of adult asthma. Here we examine the effect of salmeterol xinafoate (SX) and fluticasone propionate (FP) alone and in combination on the immunological activation of human cultured mast cells (HCMC)in vitro. METHODS: HCMC were passively sensitized with IgE antibody and then activated by challenging with anti-IgE antibody. The effect of drugs on the activation of mast cells was examined by measuring the amount of released chemical mediators (histamine, leukotrienes (LT) and prostaglandin D(2) (PGD(2))) and granulocyte macrophage colony stimulating factor (GM-CSF). RESULTS: The release of each chemical mediator was inhibited by 10-9-10-8M SX but not by 10-10-10-7M FP. The production of GM-CSF was inhibited by a concentration of 10-8M in both drugs and the inhibition was augmented by combined treatment with 10-11M of each drug. CONCLUSIONS: The immunological release of chemical mediators (histamine, LT, PGD(2)) from HCMC was inhibited by SX but not by FP. SX and FP inhibited the production of GM-CSF by HCMC and both drug showed synergistic inhibition in the production of GM-CSF.

Adrenergic beta-2 Receptor Agonists↗

Production of matrix metalloproteinases in human cultured mast cells: involvement of protein kinase C-mitogen activated protein kinase kinase-extracellular signal-regulated kinase pathway.

BACKGROUND: Matrix metalloproteinases (MMPs) have been reported to play crucial roles in the migration of inflammatory cells through basement membrane components. To confirm the role of mast cells as a source of MMPs, we investigated the production of MMP and its pathway in human cultured mast cells (HCMC). We also investigated the production of tissue inhibitors of metalloproteinase (TIMPs). METHODS: HCMC was stimulated with phorbor 12-miristate 13-acetate (PMA) and/or calcium ionophore A23187 (A23187), and the resulting MMP production was evaluated by gelatin zymography and western blotting. Expression of MMP and TIMP mRNA was also examined. Granulocyte macrophage-colony stimulating factor (GM-CSF) was measured by ELISA and activation of extracellular signal-regulated kinase (ERK) was evaluated by western blotting. RESULTS: We detected the de novo synthesis of MMP-9 in HCMC after stimulation with PMA and found that the synthesis was mediated through protein kinase C-mitogen activated protein kinase kinase (MEK)-ERK pathway. The MMP-9 production induced by PMA was suppressed by simultaneous treatment with A23187, whereas GM-CSF production was potentiated. We also detected the expression of mRNA for membrane-type 1 (MT1)-MMP, TIMP-1 and TIMP-2 after stimulation with PMA. Glucocorticoids and flavonoids inhibited MMP-9 production, and TIMPs and MMP inhibitors inhibited the gelatinolytic activity of mast cell-derived MMP-9. Furthermore, phenylmethylsulfonyl fluoride, a protease inhibitor, inhibited the conversion from proMMP-9 to active MMP-9. CONCLUSIONS: These results suggest that the human mast cell is a leading member of MMP production, and the production, activation and activity are controllable by pharmacological agents.

Cell Culture Techniques↗