WordNet

secret; "keep it dark"
absence of light or illumination (同)darkness
an unenlightened state; "he was in the dark concerning their intentions"; "his lectures dispelled the darkness" (同)darkness
showing a brooding ill humor; "a dark scowl"; "the proverbially dour New England Puritan"; "a glum, hopeless shrug"; "he sat in moody silence"; "a morose and unsociable manner"; "a saturnine, almost misanthropic young genius"- Bruce Bliven; "a sour temper"; "a sullen crowd" (同)dour, glowering, glum, moody, morose, saturnine, sour, sullen
marked by difficulty of style or expression; "much that was dark is now quite clear to me"; "those who do not appreciate Kafkas work say his style is obscure" (同)obscure
(used of color) having a dark hue; "dark green"; "dark glasses"; "dark colors like wine red or navy blue"
brunet (used of hair or skin or eyes); "dark eyes"
devoid of or deficient in light or brightness; shadowed or black; "sitting in a dark corner"; "a dark day"; "dark shadows"; "dark as the inside of a black cat"
not giving performances; closed; "the theater is dark on Mondays"
small room in which a monk or nun lives (同)cubicle
a device that delivers an electric current as the result of a chemical reaction (同)electric cell
a room where a prisoner is kept (同)jail cell, prison cell
(biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
any small compartment; "the cells of a honeycomb"
a small unit serving as part of or as the nucleus of a larger political movement (同)cadre

PrepTutorEJDIC

『暗い』やみの / (毛髪・皮膚・目の)『浅黒い』,(色の)濃い / 陰うつな,陰気な(gloomy) / 腹黒い,悪意のある(evil) / 隠した,秘密の / (意味が)明らかでない,なぞめいた / 未発の;無知の / 〈U〉《the~》『やみ』,暗がり(darkness) / 《冠詞なしで》『夜』(night);『日暮れ』(nightfall) / 〈U〉暗い色,濃い陰
(刑務所の)『独房』;(修道院の)小さい独居室 / (ミツバチの)みつ房,巣穴 / 小さい部屋 / 『細胞』 / 電池 / 花粉室 / (共産党などの)細胞
大胆な,ずぶとい(bold) / 思いきった,ざん新な / {名}〈U〉 / 大胆不敵,勇敢さ

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/21 03:51:16」(JST)

wiki en

Dark cells refers to specialized nonsensory epithelial cells found on either side of the vestibular organs, and lining the endolymphatic space. These dark-cell areas in the vestibular organ are structures involved in the production of endolymphatic fluid (endolymph), secreting potassium towards the endolymphatic fluid. Dark cells take part in fluid homeostasis to preserve the unique high-potassium and low-sodium content of the endolymph and also maintain the calcium homeostasis of the inner ear.^[1]

Morphological and immunohistochemical studies in several species have indicated that these dark cell areas also form a single layer resting on top of pigmented cells at the base of the cristae ampullaris in the semi-circular canals and around the utricular macula.^[1]

Importance and research in dark cells

Many species (with recent studies done on dogs) are affected by balance disorders and hearing problems that can be caused by a problem in the dark-cell areas in the vestibular endorgans. Studies researching damaged dark cells due to genetic abnormalities or therapeutics are very important in attempting to understand the onset and mechanism of said balance impairments.^[2]

Dogs have been used as models due to similarities between humans and dogs with regards to inner ear size, inner ear lesions and susceptibility to ototoxins.^[2]

Dark cell structure

Dark cells are morphologically and functionally similar to marginal cells of the stria vascularis as they both display characteristics of fluid transport tissue; however, studies indicate an earlier histological and immunohistological maturity in the dark-cell areas compared to the stria vascularis.^[1]

The dark cell epithelium consists of cells with a multitude of pinocytotic vesicles near their luminal surface. A numerable portion of infoldings occurs at the basal end of the dark cell toward the basal membrane. These infoldings contain a high quantity of mitochondria. The nucleus of the dark cell is displaced toward the surface.^[3]

Mechanism of dark cells

Vestibular dark cells transport potassium into the inner ear endolymph, a potassium-rich fluid whose homeostasis is essential for hearing and balance. Dark cell regions of the vestibular system are involved in active (energy consuming) ion transport to maintain the unusual endolymph composition. In other words, dark cells utilize the Na⁺/K⁺-ATPase pump in order to transport potassium.^[4]

As mentioned in dark cell structure, the basolateral membranes of vestibular dark cells are highly folded, allowing the enclosure of the numerous large mitochondria, and they contain high levels of Na⁺/K⁺-ATPase in both alpha and beta isoforms, transporting potassium into the cell in exchange for sodium while consuming ATP.^[5] The infoldings also create large surface area over which ion exchange can take place and the plethora of mitochondria enclosed provides the needed energy source of ATP for active transport.

The basolateral membrane also contains a Na⁺/K⁺/Cl^—-co-transporter, (NKCC1) which transports all three ions into the cell.^[6] The transport of sodium into the cell enhances the effect of the Na+/K+-ATPase pump by stimulating the outward transport of Na+, and therefore, the inward transport of K+. Na-K-Cl cotransporter is the therapeutic target of action for loop diuretics in the kidney and loop diuretics have rapid, acute ototoxic side effects through an action on the co-transporter in vestibular dark cells. These acute ototoxic side effects inhibit ion transport resulting in accumulation of ions in the extracellular space leading to edema.^[7]

The apical membranes of the dark cells also have a k+ channel which is formed of two subunits, the KCNE1 regulatory protein and the KCNQ1 channel proteins.^[8] This channel provides the pathway through which K+ is secreted into the endolymph. As a result, mutations in the KCNE1 gene disrupt endolymph production in the vestibular system, leading to the collapse of the epithelia of the roof of the utricle, saccule and ampullae, as well as dysfunction of the vestibular sensory organs.^[8]

References

^ ^a ^b ^c Kimura RS (June 1969). "Distribution, structure, and function of dark cells in the vestibular labyrinth". Ann. Otol. Rhinol. Laryngol. 78 (3): 542–61. PMID 5305759.
^ ^a ^b Pickrell JA, Oehme FW, Cash WC (February 1993). "Ototoxicity in dogs and cats". Semin. Vet. Med. Surg. Small Anim. 8 (1): 42–9. PMID 8456203.
^ Takumida, M (1999). "Vestibular Dark Cells and Supporting Cells.". Science Links Japan. Retrieved 8 August 2013.
^ Quraishi IH, Raphael RM (January 2007). "Computational model of vectorial potassium transport by cochlear marginal cellsand vestibular dark cells". Am. J. Physiol., Cell Physiol. 292 (1): C591–602. doi:10.1152/ajpcell.00560.2005. PMID 17005601.
^ McGuirt JP, Schulte BA (July 1994). "Distribution of immunoreactive alpha- and beta-subunit isoforms of Na,K-ATPase in the gerbil inner ear". J. Histochem. Cytochem. 42 (7): 843–53. doi:10.1177/42.7.8014467. PMID 8014467.
^ Crouch JJ, Sakaguchi N, Lytle C, Schulte BA (June 1997). "Immunohistochemical localization of the Na-K-Cl co-transporter (NKCC1) in the gerbil inner ear" (PDF). J. Histochem. Cytochem. 45 (6): 773–8. doi:10.1177/002215549704500601. PMID 9199662.
^ Forge A, Wright T (2002). "The molecular architecture of the inner ear". Br. Med. Bull. 63: 5–24. doi:10.1093/bmb/63.1.5. PMID 12324381.
^ Vetter DE, Mann JR, Wangemann P et al. (December 1996). "Inner ear defects induced by null mutation of the isk gene". Neuron 17 (6): 1251–64. doi:10.1016/S0896-6273(00)80255-X. PMID 8982171.

UpToDate Contents

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1. 皮膚扁平上皮癌（SCC）の臨床的特徴および診断 clinical features and diagnosis of cutaneous squamous cell carcinoma scc
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English Journal

8-C N-ethyl-2-pyrrolidinone substituted flavan-3-ols as the marker compounds of Chinese dark teas formed in the post-fermentation process provide significant antioxidative activity.

Wang W1, Zhang L1, Wang S1, Shi S1, Jiang Y1, Li N1, Tu P2.Author information 1State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China.2State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China. Electronic address: pengfeitu@bjmu.edu.cn.AbstractPhytochemical investigation of the aqueous extract of pu-erh tea afforded eight novel 8-C N-ethyl-2-pyrrolidinone substituted flavan-3-ols (puerins I-VIII) by (1)H, (13)C, two-dimensional nuclear magnetic resonance (NMR) and high-performance liquid chromatography with diode array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI/MS) analysis. Comparative chemical analysis of green tea, black tea and Chinese dark teas confirmed that these compounds were the marker compounds of Chinese dark teas. Furthermore, fungal fermentation was indispensable for the biosynthesis of these novel compounds. Through single fungal fermentation, it was proved that catechins and theanine were the precursors of puerins I-VIII. HPLC-DAD-ESI/MS analysis elucidated the biosynthetic pathway for puerins I-VIII. Puerins I-IV have potential protective effects for the human micro-vascular endothelial cells (HMEC) injury induced by hydrogen dioxide compared to other tea polyphenols. 8-C N-ethyl-2-pyrrolidinone substituted flavan-3-ols could be used in the quality control and authentication of Chinese dark teas.
Food chemistry.Food Chem.2014 Jun 1;152:539-45. doi: 10.1016/j.foodchem.2013.10.117. Epub 2013 Nov 1.
Phytochemical investigation of the aqueous extract of pu-erh tea afforded eight novel 8-C N-ethyl-2-pyrrolidinone substituted flavan-3-ols (puerins I-VIII) by (1)H, (13)C, two-dimensional nuclear magnetic resonance (NMR) and high-performance liquid chromatography with diode array detection and elect
PMID 24444972

Application of low-energy scanning transmission electron microscopy for the study of Pt-nanoparticle uptake in human colon carcinoma cells.

Blank H1, Schneider R, Gerthsen D, Gehrke H, Jarolim K, Marko D.Author information 1Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie (KIT) , 76128 Karlsruhe , Germany.AbstractHigh-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) in a scanning electron microscope facilitates the acquisition of images with high chemical sensitivity and high resolution. HAADF STEM at low electron energies is particularly suited to image nanoparticles (NPs) in thin cell sections which are not subjected to poststaining procedures as demonstrated by comparison with bright-field TEM. High membrane contrast is achieved and distinction of NPs with different chemical composition is possible at first sight. Low-energy HAADF STEM was applied to systematically study the uptake of Pt-NPs with a broad size distribution in HT29 colon carcinoma cells as a function of incubation time and incubation temperature. The cellular dose was quantified, that is, the amount and number density of NPs taken up by the cells, as well as the particle-size distribution. The results show a strong dependence of the amount of incubated NPs on the exposure time which can be understood by considering size-dependent diffusion and gravitational settling of the NPs in the cell culture medium.
Nanotoxicology.Nanotoxicology.2014 Jun;8(4):433-46. doi: 10.3109/17435390.2013.796535. Epub 2013 May 9.
High-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) in a scanning electron microscope facilitates the acquisition of images with high chemical sensitivity and high resolution. HAADF STEM at low electron energies is particularly suited to image nanoparticles (NPs) in
PMID 23590554

The effects of engineered nanoparticles on the cellular structure and growth of Saccharomyces cerevisiae.

Bayat N1, Rajapakse K, Marinsek-Logar R, Drobne D, Cristobal S.Author information 1Department of Biochemistry and Biophysics, Stockholm University , Stockholm , Sweden.AbstractIn order to study the effects of nanoparticles (NPs) with different physicochemical properties on cellular viability and structure, Saccharomyces cerevisiae were exposed to different concentrations of TiO2-NPs (1-3 nm), ZnO-NPs (<100 nm), CuO-NPs (<50 nm), their bulk forms, Ag-NPs (10 nm) and single-walled carbon nanotubes (SWCNTs). The GreenScreen assay was used to measure cyto- and genotoxicity, and transmission electron microscopy (TEM) used to assess ultrastructure. CuO-NPs were highly cytotoxic, reducing the cell density by 80% at 9 cm(2)/ml, and inducing lipid droplet formation. Cells exposed to Ag-NPs (19 cm(2)/ml) and TiO2-NPs (147 cm(2)/ml) contained dark deposits in intracellular vacuoles, the cell wall and vesicles, and reduced cell density (40 and 30%, respectively). ZnO-NPs (8 cm(2)/ml) caused an increase in the size of intracellular vacuoles, despite not being cytotoxic. SWCNTs did not cause cytotoxicity or significant alterations in ultrastructure, despite high oxidative potential. Two genotoxicity assays, GreenScreen and the comet assay, produced different results and the authors discuss the reasons for this discrepancy. Classical assays of toxicity may not be the most suitable for studying the effects of NPs in cellular systems, and the simultaneous assessment of other measures of the state of cells, such as TEM are highly recommended.
Nanotoxicology.Nanotoxicology.2014 Jun;8(4):363-73. doi: 10.3109/17435390.2013.788748. Epub 2013 Apr 22.
In order to study the effects of nanoparticles (NPs) with different physicochemical properties on cellular viability and structure, Saccharomyces cerevisiae were exposed to different concentrations of TiO2-NPs (1-3 nm), ZnO-NPs (<100 nm), CuO-NPs (<50 nm), their bulk forms, Ag-NPs (10 nm) and
PMID 23521755

Japanese Journal

有機薄膜太陽電池の現状と将来展望(<特集>次世代太陽電池)

吉田郵司
日本エネルギー学会誌 91(5), 376-381, 2012-05-20
… We found a lot of dark spots in the EL image of OPV as an initial degradation area. …
NAID 110009457744

Optimization of light for growth, photosynthesis, and hydrocarbon production by the colonial microalga Botryococcus braunii BOT-22

Sakamoto Kohei,Baba Masato,Suzuki Iwane,Watanabe Makoto M.,Shiraiwa Yoshihiro,馬場将人,鈴木石根,渡邉信,白岩善博
Bioresource technology 110, 474-479, 2012-04
… The lipid and sugar contents were approximately 40% and 20–30% of the cell dry weight, respectively, and about half of the lipids were liquid hydrocarbons. … After 16 days of incubation in the dark, lipid and sugar, but not hydrocarbon content decreased. …
NAID 80022463121

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