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141.
142.
Nana Kawasaki Tsuyoshi Tanimoto Akira Tanaka Takao Hayakawa Nobuyuki Miyasaka 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1994,656(2)
Non-protein-bound iron in human synovial fluid was determined using high-performance liquid chromatography with electrochemical detection. The procedure was based on the separation of the iron—diethylenetriaminepentaacetic acid (DPTA) complex formed directly on a chromatographic column containing an anion-exchange resin followed by electrochemical detection. The method enabled more than 0.1 μM Fe(III) to be determined with an injection volume of 10 μl. A mixture of synovial fluid, 20 μM DTPA and acetate buffer was incubated in the presence and absence of superoxide (O−2) generated by a xanthine—xanthine oxidase system and was ultrafiltered through a 30 000 molecular mass cut-off filter. No iron was detected in the ultrafiltrate at physiological pH. However, the presence of iron was observed in the ultrafiltrate at low pH, and O−2 and decreased pH, iron may be released into the synovial fluid. 相似文献
143.
The Effect of the B Subunit of Cholera Toxin on the Action of Nerve Growth Factor on PC12 Cells 总被引:3,自引:1,他引:2
Tatsuro Mutoh Akira Tokuda Gordon Guroff Norio Fujiki 《Journal of neurochemistry》1993,60(4):1540-1547
Abstract: Exogenous gangliosides, especially ganglioside GM1 (GM1), seem to potentiate the action of nerve growth factor (NGF). We have examined the possible regulation of the NGF signaling pathway in PC12 cells by the B subunit of cholera toxin (CTB), which binds to endogenous GM1 specifically and with a high affinity. CTB treatment (1 μg/ml) enhanced NGF-induced neurite outgrowth from PC12 cells, NGF-induced activation of ribosomal protein S6 kinase, and NGF-induced stimulation of trk phosphorylation. CTB plus NGF also caused a greater inhibition of [3 H]-thymidine incorporation into DNA than did NGF alone. These enhancing effects of CTB were blocked by the presence of cytochalasin B in the culture medium but were not affected by the presence of colchicine or by the depletion of Ca2+ in the medium. 125 I-NGF binding experiments revealed that CTB treatment did not affect the specific binding of NGF to the cells. These results strongly suggest that the binding of cell surface GM1 by CTB modulates the pathway of intracellular signaling initiated by NGF and that the association of CTB with a cytoskeletal component is essential for these effects. 相似文献
144.
Tsuyoshi Kihara Masato Ikeda Hiroshi Miyazaki Akira Matsushita 《Journal of neurochemistry》1993,61(5):1859-1864
Abstract: The in vivo microdialysis method was used to study the effect of the cholecystokinin-related peptide, ceruletide, on extracellular levels of dopamine (DA) in the striatum following perfusion with various K+ concentrations. Increasing the K+ concentration in the perfusate from 4 to 15 or 17.5 m M did not change basal DA release or release evoked by electrical stimulation of the medial forebrain bundle (MFB). However, when the perfusing solution contained 20 or 30 m M K+ , dose-dependent reductions of both basal and MFB-stimulated DA release occurred. Subcutaneous administration of ceruletide at 160 μg/kg had no influence on the basal or MFB-stimulated DA release with 4 or 15 m M K+ in the perfusate. However, after perfusion with 17.5 m M K+ , ceruletide significantly attenuated the basal and MFB-stimulated DA release. Carbachol (10 μ M ) locally applied via the dialysis probe also attenuated MFB-stimulated DA release after perfusion with 17.5 m M K+ . From these results, we conclude that under appropriate depolarization of striatal DA terminals, ceruletide induces further depolarization and inactivation of nigrostriatal DA terminals. The present data suggest that this effect may be mediated via intrinsic cholinergic neurons in the striatum. 相似文献
145.
Laminin A, B1, and B2 Chain Gene Expression in Transected and Regenerating Nerves: Regulation by Axonal Signals 总被引:3,自引:0,他引:3
Manabu Doyu Gen Sobue Eishuku Ken Koji Kimata† Tamayuki Shinomura† Yoshihiko Yamada‡ Terunori Mitsuma Akira Takahashi 《Journal of neurochemistry》1993,60(2):543-551
Abstract: Laminin A, B1, and B2 chain mRNA levels in degenerating and regenerating mouse sciatic nerves were examined using northern blot analysis. In normal intact nerves, B1 and B2 mRNA steady-state levels were high, but when the nerves were crushed, the steady-state levels of B1 and B2 mRNA per milligram wet tissue weight of the distal segments of the nerves increased five- to eightfold over that of control levels as the total RNA and β-actin mRNA levels increased, suggesting that these increases were the consequence of Schwann cell proliferation after axotomy. When the steady-state levels of B1 and B2 mRNA were normalized as the ratio to total RNA or β-actin mRNA levels, however, they drastically decreased to about 20% of the normal nerve levels in the nerve segments distal to both the crush and transaction sites 1 day after injury. In the crushed nerves, B1 and B2 mRNA levels gradually increased as the regenerating nerves arrived at the distal segments and reestablished normal axon–Schwann cell contact, and then returned to normal levels on the 21 st day. In the transected nerves, where Schwann cells continued to be disconnected from axons, both B1 and B2 mRNA levels remained low. Cultured Schwann cells expressed detectable levels of B1 and B2 chain mRNA which significantly increased when the cells were cocultured with sensory neurons. However, mRNA for A chain was not detectable in the normal, axotomized nerves or in cultured Schwann cells. These data indicate that Schwann cells express laminin B1 and B2 chain mRNA that are up-regulated by axonal or neuronal contact, but they do not express A chain mRNA. 相似文献
146.
Transient expression of the chloramphenicol acetyl-transferase (CAT) gene under the control of simian virus 40 (SV40), Moloney murine leukemia virus, human T cell leukemia virus, and cytomegalovirus promoters was stimulated by the differentiation of F9 stem cells into primitive endoderm, but repressed again by further differentiation into visceral endoderm. Deletion mutants of the SV40 enhancer showed that a similar set of motifs is critical for CAT expression at all stages of F9 differentiation, but differentiation dependency was observed even in their absence. The stability of transient gene expression under the control of the SV40 promoter was markedly dependent on F9 differentiation. Appreciable expression was detected even in undifferentiated F9 cells immediately after gene transfection, was maximal at 12 h and declined rapidly thereafter. On the other hand, expression in primitive endoderm increased until 72 h. The decline was accelerated again in visceral endoderm. This shift was somewhat specific to the virus promoter since CAT expression in undifferentiated F9 cells under the control of the elongation factor 1α promoter was more stable than for virus promoters tested. Thus, the change in stability of expression is important for differentiation-dependent virus promoter activity. 相似文献
147.
Nobuakira Takeda Akira Tanamura Takaaki Iwai Mitsutoshi Kato Kenji Noma Makoto Nagano 《Molecular and cellular biochemistry》1993,129(2):139-143
The effects of captopril, an angiotensin-converting enzyme inhibitor, on congestive heart failure (CHF) were investigated in animal and clinical studies. Congestive heart failure was induced in rats by a combination of pressure and volume overload. Cardiac pressure overload was induced by constricting one renal artery (Goldblatt rat) and volume overload was induced by aorto-caval fistula. Captopril (100 mg/kg/day) was then administered for 14 weeks. Isometric contraction was assessed using isolated left ventricular papillary muscles. The maximum developed tension and the maximum rate of increase in tension (dT/dtmax) were decreased in untreated rats with CHF and improved in captopriltreated rats. The left ventricular myosin isoenzyme pattern was shifted towards V3 in untreated rats with CHF, and was shifted back towards V1 in the captopril-treated rats. In the clinical study, captopril (37.5–75 mg/day) was administered to patients with cardiomyopathy for 12 months. There was no effect on left ventricular mass in hypertrophic cardiomyopathy, although systolic anterior motion of the mitral valve disappeared in one patient. In dilated cardiomyopathy, however, left ventricular mass tended to decrease. These results indicate that captopril has a beneficial effect in congestive heart failure. 相似文献
148.
Mitsutoshi Kato Jie Yang Takaaki Iwai Akira Tanamura Toru Arino Osamu Kawashima Nobuakira Takeda 《Molecular and cellular biochemistry》1993,119(1-2):89-94
ADP/ATP carrier protein (AAC) is located in the mitochondrial inner membrane and has an important function in mitochondrial energy supply. This protein transports ATP to the cytoplasm and counter transports ADP into the mitochondria. J-2-N cardiomyopathic hamsters were investigated to determine the AAC content in cardiac mitochondria. After recording an electrocardiogram and collecting blood, the cardiac mitochondria were isolated. The mitochondrial membranes were labelled with eosin-5-maleimide (EMA) and separated on SDS polyacrylamide gels. The position of the AAC component was identified by exposing the gel under UV light, and the AAC content was determined by densitometry after staining with Coomassie blue. The AAC content ratio was significantly decreased in both 10-week-old and 1-year survived J-2-N hamsters when compared to control Golden hamster. Among 10-week-old J-2-N hamsters, the decrease in the AAC content ratio was more marked for the animals with more severe myocardial damage. The H+-ATPase activities of mitochondrial membrane were higher in 10-week-old J-2-N hamsters than in control hamsters. These results suggest that the decrease of AAC in J-2-N hamster plays an important role in the pathogenesis of cardiomyopathy in J-2-N hamsters. 相似文献
149.
Tokuo Ogawa Junichi Sugenoya Norikazu Ohnishi Keiko Natsume Kazuno Imai Yoshikazu Kandori Akira Ishizuka Atsushi Osada 《European journal of applied physiology and occupational physiology》1993,67(4):354-359
We have examined the nonparallel changes in tampanic membrane temperatures (T
ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T
ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T
ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T
ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T
ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T
ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T
ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation. 相似文献
150.
The helicities in various fragments of bovine serum albumin (BSA) were examined in the thermal denaturation and in sodium docecyl sulfate (SDS) denaturation. The thermal denaturation was examined in a temperature range between 2 and 65°C. The helicity decreased with a rise of temperature and it recovered to some degree upon cooling temperature. A rather high reversibility was observed in the BSA fragments, which were located in the N-terminal of the parent protein and then contained the first large loop with no disulfide bridge. The high reversibility was available also for the helicity in the first large loop of the fragment, disulfide bridges of which were reduced. The fragments, which were smaller than one domain, became unstable in the SDS denaturation. The helicities of such fragments decreased in lower SDS concentrations compared with those of the intact BSA and the large fragments, which contained one or more domains. A resistance to the SDS denaturation appeared in the helices of every large loop even after the fragmentation. On the other hand, helicities of the fragments decreased to 20–25% upon the reduction of disulfide bridges. However, the helicities of these fragments increased to 35–40% in the SDS denaturation. 相似文献