巻号一覧
214 巻 (2008)
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214 巻, 3 号
March
選択された号の論文の12件中1～12を表示しています
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Editorial
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Shigeki Shibahara2008 年 214 巻 3 号 p. 165
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーPDF形式でダウンロード (88K)
Reviews
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Hisatake Kondo, Hiroo Iwasa, Sachiko Saino-Saito2008 年 214 巻 3 号 p. 167-174
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーIn conventional transmission electron microscopy (EM), thinly sectioned specimens embedded in epoxy resin are observed. However, because of a substantial level of electron density of epoxy resin, the possibility cannot be ruled out that bio-structures having electron density similar to that of epoxy resin are not clearly recognized and thus are neglected or misinterpreted in conventional EM. This was the reason to require for embedment-free EM. Embedment-free sections have already been made available reliably by transient embedding in polyethylene glycol (PEG) and subsequent de-embedding through immersion in water, and further by critical-point drying, and this embedment-free EM is thus termed PEG-EM. However, this PEG-EM has not been successful to attract reasonable attention from electron microscopists and instead been misunderstood as a non-reliable method. In this paper, the remarkably enhanced contrast and electron translucency of any observation targets in PEG-EM are clearly demonstrated by comparing with images in conventional EM of adipocytes and neural myelin as examples. These features of PEG-EM, together with faithful correspondence in EM images of any individual substructures between the two methods, confirm the reliability of PEG-EM. Furthermore, the much higher thickness of embedment-free sections together with these features makes the PEG-EM more advantageous than the conventional EM for three-dimensional appreciation of structural elements, which is made by stereo-viewing of sections or by EM tomography. Therefore, the PEG-EM is regarded as an important adjunct to the conventional EM for histological studies and wide application of this method may unravel a new level of histology.抄録全体を表示PDF形式でダウンロード (1742K) -
Masahiko Watanabe2008 年 214 巻 3 号 p. 175-190
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーCerebellar Purkinje cells (PCs) play a principal role in motor coordination and motor learning. To fulfill these functions, PCs receive and integrate two types of excitatory inputs, climbing fiber (CF) and parallel fiber (PF). CFs are projection axons from the inferior olive, and convey error signals to PCs. On the other hand, PFs are T-shaped axons of cerebellar granule cells, and convey sensory and motor information carried through the pontocerebellar and spinocerebellar mossy fiber pathways. The most remarkable feature of PC circuits is the highly territorial innervation by these two excitatory afferents. A single climbing CF powerfully and exclusively innervates proximal PC dendrites, whereas hundreds of thousands of PFs innervate distal PC dendrites. Recent studies using gene-manipulated mice have been elucidating that the PC circuitry is formed and maintained by molecular mechanisms that fuel homosynaptic competition among CFs and heterosynaptic competition between CFs and PFs. GluRδ2 (a PC-specific glutamate receptor) and precerebellin or Cbln1 (a granule cell-derived secretory protein) cooperatively work for selective strengthening of PF-PC synapses, and prevent excessive distal extension of CFs that eventually causes multiple innervation at distal dendrites. In contrast, P/Q-type Ca2+ channels, which mediate Ca2+ influx upon CF activity, selectively strengthen the innervation by a single main CF, and expel PFs and other CFs from proximal dendrites that it innervates. Therefore, we now understand that owing to these mechanisms, territorial innervation by CFs and PFs is properly structured and mono-innervation by CFs is established. Several key issues for future study are also discussed.抄録全体を表示PDF形式でダウンロード (3428K) -
Hiroyuki Sakagami2008 年 214 巻 3 号 p. 191-198
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーADP ribosylation factor 6 (ARF6) is a member of the ARF family of small GTPases, which mediates a variety of neuronal functions accompanying the structural changes of developing and mature neurons through its regulation of actin cytoskeleton reorganization and membrane traffic. The activation of ARF6 is strictly regulated by guanine nucleotide exchange factors (GEFs). The EFA6 family is the first member that was identified to be a specific GEF for ARF6 and comprises four structurally related polypeptides (EFA6A, EFA6B, EFA6C and EFA6D). Since the cellular and subcelllular localization of GEFs is a critical determinant for the spatiotemporal activation of ARF6 in neurons, I have focused on the EFA6 family from the anatomical point of view to understand the neuronal functions of ARF6. Three members of the EFA6 family (EFA6A, EFA6C and EFA6D) are abundantly expressed in the mouse brain with distinct spatiotemporal patterns. Interestingly, they are enriched particularly in the postsynaptic density fraction, shedding light on the importance of the EFA-ARF6 pathway in neuronal synapses. Here, I will review the recent advances in the expression and functions of the EFA6 family in the nervous system.抄録全体を表示PDF形式でダウンロード (534K) -
Kaoru Goto, Yasukazu Hozumi, Tomoyuki Nakano, Sachiko Saino-Saito, Alb ...2008 年 214 巻 3 号 p. 199-212
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーDiacylglycerol kinase (DGK) metabolizes diacylglycerol (DG), a glycerolipid containing two acyl chains, to convert phosphatidic acid. DG is produced through phosphoinositide turnover within the membrane and is well known to act as a second messenger that modulates the activity of protein kinase C in the cellular signal transduction. Recent studies have revealed that DG also activates several proteins, including Ras guanine-nucleotide releasing protein and ion channels such as transient receptor potential proteins. Therefore, DGK is thought to participate in a number of signaling cascades by modulating levels of DG. Previous studies have disclosed that DGK is composed of a family of the isozymes, which differ in the structure, enzymological property, gene expression and localization, subcellular localization, and binding molecules. The present review focuses on the stories of phosphoinositide turnover and DG, including historical views, structural features, metabolism, and relevant cellular phenomena, together with the characteristics of DGK isozymes and the pathophysiological findings on animal studies using knockout mice and models for human diseases. Now it is being revealed that the structural and functional diversity and heterogeneity of and around DGK support the proper arrangement of the complex signal transduction machinery.抄録全体を表示PDF形式でダウンロード (1099K) -
Yuji Owada2008 年 214 巻 3 号 p. 213-220
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーLong chain fatty acids are important nutrients for brain development and function. However, the molecular basis of their actions in the brain is still to be clarified. Fatty acid-binding proteins (FABPs) belong to the multigene family of the intracellular lipid-binding protein. FABPs bind to long chain fatty acids, being involved in the promotion of cellular uptake and transport of fatty acids, the targeting of fatty acids to specific metabolic pathways, and the regulation of gene expression. FABPs are widely expressed in mammalian tissues, with distinct expression patterns for the individual protein. Although FABPs have been implicated to serve as regulators in systemic cellular metabolic pathways, recent studies have demonstrated the ability of FABPs to regulate functions of the brain, one of the most fat-enriched tissues in the body. This review summarizes the localization of FABPs in the brain, and recent progress in elucidating the function of FABPs in the brain.抄録全体を表示PDF形式でダウンロード (348K)
Regular Contributions
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Yuko Takahashi-Horiuchi, Kanji Sugiyama, Hideaki Sakashita, Osamu Aman ...2008 年 214 巻 3 号 p. 221-230
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーHeat shock protein 27 (Hsp27) has been suggested to participate in the cell proliferation and differentiation during tissue development. In fact, we have demonstrated the transient occurrence of Hsp27 during the differentiation of salivary gland acinar cells in postnatal rats. The purpose of the present study is to explore the potential role of Hsp27 in the proliferation and differentiation of the acinar cells during regeneration of the salivary gland. Using the experimental regeneration model of the rat submandibular gland after the release of duct ligation, the spatio-temporal localization of Hsp27 was investigated in immunohistochemistry in regenerating acini. No epithelial cells were immunoreactive for Hsp27 immediately after unligation, but Hsp27-immunoreactive cells were observed in regenerating acini located at the end portion of survived ductal tissues on the third day after unligation. The number of Hsp27-immunoreactive cells in regenerating acini reached its peak on the 5th day after unligation, and started to decline on the 7th day. They were undetectable on the 14th day. Importantly, the increase in the number of Hsp27-immunoreactive cells was preceded by the decline in the cell proliferative activity, and Hsp27-immunoreactivity declined and disappeared in conjunction with the progression of acinar cell differentiation, as judged by the double-immunostaining for Hsp27 and proliferating cell nuclear antigen, a cell proliferation marker, or glycine-rich protein-α, a specific marker of differentiated acinar cells. All the findings suggest that Hsp27 is expressed with the transition from the cell proliferation to differentiation of the acinar precursor cells during the regenerating process.抄録全体を表示PDF形式でダウンロード (3094K) -
Wiphawi Hipkaeo, Natthiya Sakulsak, Tomohiko Wakayama, Miyuki Yamamoto ...2008 年 214 巻 3 号 p. 231-245
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーIn the submandibular gland (SMG) of mice, a duct portion called the granular convoluted tubule (GCT) is developed preferentially in males with puberty. This sexual dimorphism is androgen-dependent, but the underlying molecular mechanisms are unclear. We have demonstrated that the expression of a transcription factor JunD is regulated in association with the androgen-induced differentiation of GCT cells from striated duct (SD) cells. Menin, a nuclear protein encoded by the MEN1 tumor-suppressor gene, is known to bind JunD, thereby inhibiting its activity. In the present study, we examined the expression of menin in the mouse SMG by use of Northern blotting, Western blotting, and immunohistochemistry. Immunoreactivity for menin was higher in the female than male gland, and localized to the nuclei of intercalated duct cells and a subpopulation of SD cells. In contrast, GCT cells in males appeared negative for menin. The levels of menin in the SMG were increased with castration in males and decreased by repeated administration of testosterone to females or to castrated males. After a single administration of testosterone to females, many SD cells newly gained nuclear menin, which was lost as the cells converted to GCT cells by 48 hrs. These patterns of the expression and localization of menin were quite similar to those of JunD. Furthermore, the coimmunoprecipitation analysis of the SMG homogenates indicated that menin binds JunD in vivo. The present study suggests that the JunD-menin complex plays significant roles in the androgen-dependent differentiation of the duct system in the mouse SMG.抄録全体を表示PDF形式でダウンロード (3685K) -
Ming Zhou, Hui-Jing He, Osamu Tanaka, Ryoji Suzuki, Masaki Sekiguchi, ...2008 年 214 巻 3 号 p. 247-256
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーATP-sensitive K+ (KATP) channels in the kidney are considered to play roles in regulating membrane potential according to changes in the intracellular ATP concentration. They are composed of two types of subunits; the pore subunits (Kir6.1, Kir6.2), which are members of the inwardly rectifying K+ channel family, and the regulatory subunits, the sulphonylurea receptors, which belong to the ATP-binding cassette (ABC) superfamily. The sulphonylurea receptors (SURs) are receptors of sulphonylureas widely used for the treatment of type 2 diabetes mellitus. The SURs are divided into two isoforms, SUR1 and SUR2, the latter was further divided into SUR2A and SUR2B. In the present study, we have investigated the mRNA expression by RT-PCR assay, and protein expression profiles by immunoblotting, immunohistochemistry, and immunoelectron microscopy with anti SUR2A and anti SUR2B antibodies. RT-PCR detected the presence of mRNA transcripts of the SUR2A and SUR2B, while SUR1 mRNA was barely detected. In immunoblotting, SUR2A protein was detected distinctly in the microsomal fraction, weakly in the mitochondrial fraction and at negligible level in the cell membrane fraction. In contrast, the SUR2B protein was detected intensely in the microsomal fraction, with a low level in the mitochondrial fraction and scarcely in the cell membrane fraction. In immunohistochemistry SUR2A and SUR2B proteins were widely distributed in renal tubular epithelial cells, glomerular mesangial cells, and the endothelium and the smooth muscle of blood vessels. In immunoelectron microscopy, the immunoreactivity was localized in the endoplasmic reticulum and mitochondria throughout the epithelial cells for SUR2A, and dominantly in the apical cytoplasm of the cells for SUR2B. In conclusion, the regulatory subunits of the KATP channel in the rat kidney are SUR2A and SUR2B; they also are candidate regulatory subunits for the mitochondrial KATP channel.抄録全体を表示PDF形式でダウンロード (4487K) -
Akira Michimata, Takeo Kondo, Yoshimi Suzukamo, Mirei Chiba, Shin-Ichi ...2008 年 214 巻 3 号 p. 257-267
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーStroke is the leading cause of long-term disability. Accurate assessment of motor function is important for documenting disability and the effectiveness of rehabilitative treatment. The Manual Function Test (MFT) was developed to evaluate unilateral manual performance in hemiparetic patients after stroke. This test consists of eight items, including the pegboard task, an item assessing dexterity. The total MFT score can range from 0 (severely impaired) to 32 (full function). We sought to determine normative data and explore influences of age, gender, and hand dominance. Three-hundred thirty-three healthy adult subjects between 20 and 90 years old were studied. Total MFT scores showed negative relationship to age. Compared with subjects in their 20s, those 50 or more years old had lower total MFT scores for dominant hands, as did those 40 or more years old for nondominant hands. For subjects in their 30s and 50s, total MFT scores for women were greater than for men concerning nondominant hands. No such gender difference in total MFT scores was noted for dominant hands. In the pegboard test, the number of pegs achieved for dominant hands was related to age when age was 50 or over, and when age 40 or over for nondominant hands. However, rates of decline in numbers of pegs achieved were similar between hands. In determining MFT norms, total score and items testing dexterity were influenced by age, gender, and hand dominance.抄録全体を表示PDF形式でダウンロード (310K) -
Hiroyuki Takano, Toshimi Aizawa, Taichi Irie, Eiji Itoi, Shoichi Kokub ...2008 年 214 巻 3 号 p. 269-280
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーEndochondral bone formation at epiphyseal growth plate consists of the synchronized processes of chondrogenesis and cartilage ossification. Estrogen, the major female sex hormone, plays an important role in this process, particularly during the pubertal growth spurt. However, its effects on the growth plate are not completely understood. The aims of this study were to clarify the effects of estrogen on the kinetics of chondrocytes in the growth plates of 10- to 25-week-old female rabbits by studying the effects of ovariectomy or high-dose administration of estrogen on the balance between cell proliferation and death. Forty-eight Japanese white rabbits were divided into three groups: sham operated, ovariectomized, or ovariectomized with subsequent weekly injection of high dose estrogen from 10 weeks. The chondrocyte kinetics was investigated by histomorphometry and immunohistochemistry, using antibodies for caspase-3, a marker of apoptosis, and for proliferating cell nuclear antigen. Both ovariectomized and estrogen-injected rabbits showed a declination of the chondrocyte number although the latter animals indicated a more dramatic effect. Estrogen-injected rabbits showed a decrease in the cell proliferating ability together with an increase in chondrocytes undergoing apoptosis while ovariectomy mainly reduced the cell proliferating ability. Given the known importance of estrogen for bone growth, one would expect that ovariectomy and high-dose administration of estrogen would have opposite effects. However, the present study indicated that both low and high concentration had a similar effect: a decrease in the chondrocyte number compared with control, suggesting that estrogen has to be maintained within a narrow range for optimal bone growth.抄録全体を表示PDF形式でダウンロード (5295K) -
Mustafa Aparci, Ejder Kardesoglu, Selami Suleymanoglu, Gunalp Uzun, Ya ...2008 年 214 巻 3 号 p. 281-289
発行日: 2008年
公開日: 2008/03/07
ジャーナル フリーMyocardial diastolic dysfunction is the relaxation abnormality of ventricles that limits the diastolic filling and generally precedes diastolic heart failure. Diastolic dysfunction is a common finding in diabetes. Diabetic patients receive hyperbaric oxygen (HBO) therapy for non-healing lower extremity ulcers, and exposure to HBO therapy is known to influence cardiovascular functions. This study was designed to evaluate the effect of HBO therapy on myocardial diastolic function in diabetic patients. Thirty diabetic patients (18 male and 12 female, 59.9 ± 10 years old), who were planning to undergo HBO therapy, were consecutively enrolled. Myocardial diastolic function was evaluated by pulsed wave Doppler echocardiography and tissue Doppler echocardiography before the first HBO therapy and after the tenth HBO therapy session. HBO therapy improved the relaxation capability of left ventricular myocardium, which was reflected by reduction in E wave deceleration time of mitral valve inflow (286.1 ± 65.8 msec vs 214.3 ± 32.1 msec, p < 0.05). HBO therapy also affected favorably the diastolic filling dynamics of right ventricle, which was partially reflected by the changes in E wave peak velocity of tricuspid valve inflow (0.48 ± 0.07 m/sec vs 0.46 ± 0.09 m/sec, p < 0.05). Tissue Doppler parameters of mitral lateral annulus, which are better correlated with ventricular relaxation, tended to be improved after HBO therapy, but the degree of improvement was not statistically significant. In conclusion, we suggest that HBO therapy may improve the myocardial diastolic function of diabetic patients when applied repetitively.抄録全体を表示PDF形式でダウンロード (218K)
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