31 research outputs found

    Establishment of testis-specific SOX9 activation requires high-glucose metabolism in mouse sex differentiation

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    AbstractIn mouse sex differentiation, SRY promotes Sertoli cell differentiation via SOX9 action, resulting in testis formation. SRY/SOX9 also initiates various testis-specific morphogenic events including glycogenesis in pre-Sertoli cells, suggesting the importance of glucose storage for certain SRY/SOX9-downstream events in gonadal sex determination. However, it remains unclear which cell types and what molecular/cellular events require sex-dimorphic high-energy metabolic rate. Here we show that the establishment of SOX9 activation itself is a metabolically active process with sex-dimorphic high-energy requirements in gonadal sex differentiation. The glucose-deprivation and metabolic rescue experiments using genital ridge cultures of the XY/XX-wildtype and XX/Sry transgenic embryos demonstrated that, among the various somatic cell types, pre-Sertoli cells are the most sensitive to glucose starvation despite the differences between XX/Sry and XY genotypes. Moreover, our data showed that, in developing pre-Sertoli cells, the high-glucose metabolic state is required for the establishment of SOX9 expression through an ECM (extracellular matrix)-mediated feed-forward pathway. In contrast, the expression of SRY, SF1/Ad4Bp, GATA4 and WT1, as well as initiation of early SOX9 expression, is properly maintained in the glucose-deprived condition. Therefore, our results imply the metabolic importance of the high-glucose condition for the establishment of SOX9 activation in testis differentiation

    Cyclical and Patch-Like GDNF Distribution along the Basal Surface of Sertoli Cells in Mouse and Hamster Testes

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    BACKGROUND AND AIMS: In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1-positive spermatogonia in vivo. METHODOLOGY AND PRINCIPAL FINDINGS: Here we show the cyclical and patch-like distribution of immunoreactive GDNF-positive signals and their close co-localization with a subpopulation of GFRα1-positive spermatogonia along the basal surface of Sertoli cells in mice and hamsters. Anti-GDNF section immunostaining revealed that GDNF-positive signals are mainly cytoplasmic and observed specifically in the Sertoli cells in a species-specific as well as a seminiferous cycle- and spermatogenic activity-dependent manner. In contrast to the ubiquitous GDNF signals in mouse testes, high levels of its signals were cyclically observed in hamster testes prior to spermiation. Whole-mount anti-GDNF staining of the seminiferous tubules successfully visualized the cyclical and patch-like extracellular distribution of GDNF-positive granular deposits along the basal surface of Sertoli cells in both species. Double-staining of GDNF and GFRα1 demonstrated the close co-localization of GDNF deposits and a subpopulation of GFRα1-positive spermatogonia. In both species, GFRα1-positive cells showed a slender bipolar shape as well as a tendency for increased cell numbers in the GDNF-enriched area, as compared with those in the GDNF-low/negative area of the seminiferous tubules. CONCLUSION/SIGNIFICANCE: Our data provide direct evidence of regionally defined patch-like GDNF-positive signal site in which GFRα1-positive spermatogonia possibly interact with GDNF in the basal compartment of the seminiferous tubules

    Verification Firings of End-Burning Type Hybrid Rockets

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    The authors have previously proposed the concept of end-burning-type hybrid rockets, which would use cylindrical fuel grains consisting of an array of many small ports running in the axial direction, through which oxidizer gas would flow. Because of difficulty in manufacturing a fuel grain that satisfied requirements such as high volumetric filling rate (above 0.95) and microsized port intervals, the end-burning hybrid rocket had yet to be achieved. This paper reports the results of verification firing tests of a novel end-burning-type hybrid rocket made possible for the first time by recent progress in three-dimensional printing technology. The results clearly distinguish the initial transient and steady periods of the end-burning mode and prove that no oxidizer-to-fuel ratio shift occurs during firing. Because the initial transient is a period for the exit end face to attain a steady-state shape, an initial end-face shape being close to the steady-state shape can shorten this period. A firing test with fuel having tapered ports is shown to attain a steady-state shape in less than 1s, which is much shorter than the nontapered case of about 6 seconds

    Five Cases of Congenital Chylothorax Treated by Intrapleural Minocycline

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    Minocycline pleurodesis was performed on five infants with congenital chylothorax in our institutions. They could not achieve sufficient efficacy though they had received other conservative therapies. Four of the five cases obtained reduction of pleural effusion using the minocycline pleurodesis. We concluded that minocycline pleurodesis is a safe and an effective technique for congenital chylothorax

    Analysis of Metaphorical Expressions in Japanese Compositions Written by Native Chinese and Korean Speakers : From the Viewpoint of "index simile," "joined metaphor," and "contextual metaphor"

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    本稿では中韓母語話者が執筆した日本語作文における比喩表現の特徴を検討し,日本語教育ではどのような点に留意すべきかについて考察した。具体的には「中韓母語話者による逐語訳つき日本語作文コーパス」から抽出した作文データを資料に,指標比喩・結合比喩・文脈比喩という3分類に基づいて,比喩表現について分析した。一般に,比喩は母語に根差した性質を持つと考えられ,他の言語の母語話者にも問題なく理解されるとは限らない。このような理解不可能性を「言語間ハードル」と呼ぶとすると,指標比喩・結合比喩には「言語間ハードル」を乗り越える性質が内在している一方,結合比喩はそうではない,ということを明らかにした。その結合比喩のうち,特に「言語表現は同じだが,概念基盤が異なる」ケースに誤用が起きやすい。したがって他言語で比喩を書く場合には,特に結合比喩に留意すべきである,と本稿では結論した。In this study, we examined the properties of metaphorical expressions in Japanese compositions written by native Chinese and Korean speakers, considering the important factors that should be taken into consideration in Japanese language education. Specifically, we analyzed metaphorical expressions based on the three categories of "index simile," "joined metaphor," and "contextual metaphor" through compositions extracted from the Japanese Composition Corpus with Verbatim Translation by Native Chinese and Korean Speakers. In general, a metaphor is considered to be rooted in its mother tongue and hence may not be understood by the native speakers of other languages. We termed such hurdle as "interlingual hurdle" to reveal that the categories of "index simile" and "contextual metaphor" inherently exhibit the property of overcoming "interlingual hurdle," in contrast to "joined metaphor." It was observed that in the case of "joined metaphor," errors are especially likely to occur in the presence of the same linguistic expression but different conceptual basis. Therefore, this study concludes that "joined metaphor" is of primary importance in Japanese compositions

    Oxygen-15 labeled CO2, O2, and CO PET in small animals: evaluation using a 3D-mode microPET scanner and impact of reconstruction algorithms

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    Abstract Background Positron emission tomography (PET) studies using 15O-labeled CO2, O2, and CO have been used in humans to evaluate cerebral blood flow (CBF), the cerebral oxygen extraction fraction (OEF), and the cerebral metabolic rate of oxygen (CMRO2) and cerebral blood volume (CBV), respectively. In preclinical studies, however, PET studies using 15O-labeled gases are not widely performed because of the technical difficulties associated with handling labeled gases with a short half-life. The aims of the present study were to evaluate the scatter fraction using 3D-mode micro-PET for 15O-labeled gas studies and the influence of reconstruction algorithms on quantitative values. Nine male SD rats were studied using the steady state inhalation method for 15O-labeled gases with arterial blood sampling. The resulting PET images were reconstructed using filtered back projection (FBP), ordered-subset expectation maximization (OSEM) 2D, or OSEM 3D followed by maximum a posteriori (OSEM3D-MAP). The quantitative values for each brain region and each reconstruction method were calculated by applying different reconstruction methods. Results The quantitative values for the whole brain as calculated using FBP were 46.6 ± 12.5 mL/100 mL/min (CBF), 63.7 ± 7.2% (OEF), 5.72 ± 0.34 mL/100 mL/min (CMRO2), and 5.66 ± 0.34 mL/100 mL (CBV), respectively. The CBF and CMRO2 values were significantly higher when the OSEM2D and OSEM3D-MAP reconstruction methods were used, compared with FBP, whereas the OEF values were significantly lower when reconstructed using OSEM3D-MAP. Conclusions We evaluated the difference in quantitative values among the reconstruction algorithms using 3D-mode micro-PET. The iterative reconstruction method resulted in significantly higher quantitative values for CBF and CMRO2, compared with the values calculated using the FBP reconstruction method