鶏凍結精子の走査電子顕微鏡による研究

最近走査電子顕微鏡による精子の形態学的研究が行なわれるようになり, 哺乳類の精子は凍結保存により先体に著しい悪影響を被ることが知られている。一方家禽精子においても哺乳類の精子と同様に融解精子先体に著しい変化の認められることが報告されているが, 凍結融解操作によってもたらされる一連の精子の損傷について観察した報告は少ない。 本研究は光学顕微鏡と走査電子顕微鏡を用い, 錠剤化凍結法とストロー凍結法により, それぞれ二種類の希釈液を用いて凍結処理し, 融解後の鶏精子の活力および崎形精子の微細構造について観察した。その結果, 走査電子顕微鏡を用いれば, 従来の光学顕微鏡下で通常認められる首曲り畸形精子の他に精子先体の離脱や, 精子頭部末部の膨化が認められた。しかし凍結法, 希釈液によるそれら畸形精子の出現割合の差異は明らかでなかった。Recently the scanning electron microscope (SEM) is currently being used to study the morphology of normal and abnormal spermatozoa. In general, it is known that the acrosome of mammalian spermatozoa is affected by deep freezing preservation. On the other hand, HARRIS et al. also reported that the acrosome of fowl spermatozoa is influenced by deep freezing as well as in that of mammalian spermatozoa. MARQUEZ et al. reported that some swelling or distortion of the mitochondria were caused when the turkey semen has been exposed to a glycerol containing medium. But there are few reports pertaining to the series of the morphological changes in fowl spermatozoa after freezing and thawing. In the present study, the scanning electron microscope was used to observe the morphological changes observed in fowl spermatozoa before, during and after freezing and thawing of sperm cell

Disclosing crystal nucleation mechanism in lithium disilicate glass through molecular dynamics simulations and free-energy calculations

Unraveling detailed mechanism of crystal nucleation from amorphous materials is challenging for both experimental and theoretical approaches. In this study, we have examined two methods to understand the initial stage of crystal precipitation from lithium disilicate glasses using molecular dynamics simulations. One of the methods is a modified exploring method to find structurally similar crystalline clusters in the glass models, enabling us to find three different embryos, such as Li2Si2O5 (LS2), Li2SiO3 (LS) and Li3PO4 (LP), in the 33Li2O·66SiO2·1P2O5 glass (LS2P1), in which P2O5 is added as a nucleating agent. Interestingly, LS2 and LP crystals were found inside the LS2P1 glass while LS crystal appeared on the glass surface, which agrees with experimental observations. The other method is free energy calculation using a subnano-scale spherical crystal embedded in the glass model. This method, which we called Free-Energy Seeding Method (FESM), allows us to evaluate free energy change as a function of crystal radius and to identify critical size of the crystal precipitation. The free energy profiles for LS and LS2 crystal nuclei in the LS2 glass models possess maximum energy at a critical radius as expected by classical nucleation theory. Furthermore, the critical radius and the energy barrier height agree well with recent experimental investigation, proving the applicability of this method to design glass–ceramics by atomistic modeling

Diagnostic approach for patients with unidentified fever according to the classical criteria of fever of unknown origin in the field of autoimmune disorders

ArticleImmunological medicine. 42(4): 176-184 (2019)journal articl

Long-term maintenance of the mucosal healing induced by azacitidine therapy in a patient with intestinal Behçet's-like disease accompanied with myelodysplastic syndrome involving trisomy 8

ArticleImmunological medicine. 42(3): 135-141 (2019)journal articl

Imaging the midlatitude sporadic E plasma patches with a coordinated observation of spaceborne InSAR and GPS total electron content

Kilometer-scale fine structures of midlatitude sporadic E (Es) plasma patches have been directly imaged for the first time by an interferogram derived from L band Advanced Land Observation Satellite/Phased Array-type L band Synthetic Aperture Radar data obtained over southwestern Japan. The synthetic aperture radar interferogram captured the eastern part of a large-scale frontal structure of daytime midlatitude Es which spans over 250 km in the east-northeast to west-southwest direction. Fine structures are characterized by frontal and disc-shaped patches which are elongated in the same direction as the large-scale frontal structure. Length and width of the disc-shaped patches are 10–20 km and 5–10 km, respectively, and they are quasi-periodically located with a typical separation of 10–15 km. The Kelvin-Helmholtz instability with the vertical shear of zonal winds is considered to be the most likely candidate for the generation mechanism of the frontal patch and disc-shaped patches aligned in the zonal direction

Possible shear instability in the daytime midlatitude sporadic-E observed with InSAR and GPS-TEC

A coordinated observation of GPS total electron content (TEC) and space-borne interferometric synthetic aperture radar (InSAR) has been conducted to reveal both the large- and small-scale plasma structures of daytime midlatitude sporadic-E (Es). Both observations are used for the direct imaging of the plasma patches. GPS-TEC observations have shown a common frontal shape of Es elongated typically in the east-west (E-W) direction, while an interferogram derived from InSAR observation have revealed the small-scale (fine) structure of Es. Small-scale patches are aligned in the E-W direction which is the same azimuthal direction of dominant large-scale frontal structure. We speculate that the Kelvin-Helmholtz instability with the vertical shear of meridional winds is considered to be the most likely candidate for the generation mechanism of the small-scale plasma patches aligned in the zonal direction.日本地球惑星科学連合 2016年大会. P-EM16 大気圏・電離圏セッション. 2016年5月22日-5月26日. 幕張メッセ　国際会議場, 千葉県

Midlatitude sporadic-E episodes viewed by L-band split-spectrum InSAR

Sporadic-E (Es) is a layer of ionization that irregularly appears within the E region of the ionosphere and is known to generate an unusual propagation of very high frequency waves over long distances. The detailed spatial structure of Es remains unclear due to the limited spatial resolution in the conventional ionosonde observations. We detect midlatitude Es by interferometric synthetic aperture radar (InSAR), which can clarify the spatial structure of Es with unprecedented resolution. Moreover, we use the range split-spectrum method (SSM) to separate dispersive and nondispersive components in the InSAR image. While InSAR SSM largely succeeds in decomposing into dispersive and nondispersive signals, our results indicate that small-scale dispersive signals due to the total electron content anomalies are accompanied by nondispersive signals with similar spatial scale at the same locations. We also examine the effects of higher-order terms in the refractive index for dispersive media. Both of these detected Es episodes indicate that smaller-scale dispersive effects originate from higher-order effects. We interpret that the smaller-scale nondispersive signals could indicate the emergence of nitric oxide (NO) generated by the reactions of metals, Mg and Fe, with nitric oxide ion (NO+) during the Es

幼若家兎卵巣における減数分裂の開始と各発育段階の卵胞の出現時期についての組織学的観察

幼若(生後0、7、10、14、21、25、28、35、57、70、107、161日齢)および成熟家兎卵巣を用いて、減数分裂の進行と各発育段階にある卵胞の出現時期を組織学的に観察した。生後0日齢の卵巣内で減数分裂は既に開始されており(leptotene, 5.6%; zygotene, 1.4%)、10日齢ではzygotene(42.6%)、14日齢ではpachytene(51.0%)が多く、21日齢では多くの卵母細胞がdiplotene(88.0%)に達していたが、殆ど全て町紳慢細胞がdiploteneに達したのは28日齢であった。卵胞形成が初めて認められたのは7日齢であり、28日齢では多くの卵胞が一層の卵胞細胞層を持つ卵胞(Type 3a)に発育していた。Type 5bの卵胞(未熟な胞状卵胞)は57日齢以降の卵巣で観察された。107日齢ではType 7の卵胞(単一な卵胞腔を持つ卵胞)が出現した。161日齢では間質が卵巣表層部から髄質にかけて広く分布し、Type 8の卵胞(成熟卵胞)が出現した。57日齢以降の全ての胞状卵胞内の生殖細胞の直径をtype別に測定したところ、70日齢のType 6及び107日齢のType 5bの卵胞内の生殖細胞の直径と成熟家兎卵巣のType 8のものとの間に有意差は認められなかった。以上の結果より家兎における第一減数分裂は0日齢では既に開始しており、28日頃に完全に休止するものと考えられた。また、各発育段階の卵胞を組織学的観点から見た場合、70日齢頃より成熟卵子回収の可能性を示唆する卵胞が発育していることが明らかとなった。Progress of the prophase in meiosis I and time of the first appearance of follicles in each developmental stage in ovaries of young rabbits were investigated histologically. Oocytes in leptotene and zygotene were located in 5.6% and 1.4% of all ovaries of newborn rabbits, respectively, indicating that some transition of oogonia to oocytes had occurred at day 0. The percentage of oocytes in diplotene was very high (86%) on day 21, and this stage had been completed by day 28. Follicles of Type 2 (in the classification by PEDERSEN and PETERS, 1968) appeared first in ovaries of 7-day-old rabbits. Follicular formation was initiated on day 7 when oocytes within the follicles reached the stage of diplotene or the transitional phase between pachytene and diplotene. The first small antral follicles were recognized in ovaries on clay 70, meaning that formation of such follicles started between day 57 and day 70, though atretic follicles were frequently found and secondary interstitial tissue appeared at this age. Fully developed follicles (Type 8) appeared in one of two does on day 107. Through all stages of follicular growth, more developed follicles were located generally in the deep ovarian cortex adjoining the medulla and containing well developed blood vessels