280 research outputs found
Dynamical fermion masses under the influence of Kaluza-Klein fermions in extra dimensions
The dynamical fermion mass generation in the 4-dimensional brane is discussed
in a model with 5-dimensional Kaluza-Klein fermions in interaction with
4-dimensional fermions. It is found that the dynamical fermion masses are
generated beyond the critical radius of the compactified extra dimensional
space and may be made small compared with masses of the Kaluza-Klein modes.Comment: 11 pages, 3 figures, REVTeX; typos corrected, comment about the
symmetry breaking added in section 4, new references for section 1 adde
Proliferation of Luteal Steroidogenic Cells in Cattle
The rapid growth of the corpus luteum (CL) after ovulation is believed to be mainly due to an increase in the size of luteal cells (hypertrophy) rather than an increase in their number. However, the relationship between luteal growth and the proliferation of luteal steroidogenic cells (LSCs) is not fully understood. One goal of the present study was to determine whether LSCs proliferate during CL growth. A second goal was to determine whether luteinizing hormone (LH), which is known have roles in the proliferation and differentiation of follicular cells, also affects the proliferation of LSCs. Ki-67 (a cell proliferation marker) was expressed during the early, developing and mid luteal stages and some Ki-67-positive cells co-expressed HSD3B (a steroidogenic marker). DNA content in LSCs isolated from the developing CL increased much more rapidly (indicating rapid growth) than did DNA content in LSCs isolated from the mid CL. The cell cycle-progressive genes CCND2 (cyclin D2) and CCNE1 (cyclin E1) mRNA were expressed more strongly in the small luteal cells than in the large luteal cells. LH decreased the rate of increase of DNA in LSCs isolated from the mid luteal stage but not in LSCs from the developing stage. LH suppressed CCND2 expression in LSCs from the mid luteal stage but not from the developing luteal stage. Furthermore, LH receptor (LHCGR) mRNA expression was higher at the mid luteal stage than at the developing luteal stage. The overall results suggest that the growth of the bovine CL is due to not only hypertrophy of LSCs but also an increase in their number, and that the proliferative ability of luteal steroidogenic cells decreases between the developing and mid luteal stages
Mastoparan inhibits phosphoinositide hydrolysis via pertussis toxin-intensive G-protein in human astrocytoma cells
AbstractMastoparan inhibited [3H]inositol phosphate accumulation induced by carbachol as well as cyclic AMP accumulation induced by isoproterenol in 1321N1 human astrocytoma cells. Mastoparan inhibited GTPγS-induced, but not Ca2+-induced, [3H]inositol phosphate accumulation in membrane preparations with an IC50 of approximately 10 μM. The inhibitory effect of mastoparan on carbachol-induced [3pH]inositol phosphate accumulation was resistant to pertussis toxin (IAP) treatment in intact cells. These results suggest that mastoparan inhibits phospholipase C in human astrocytoma cells via a GTP binding protein, which is not a substrate for IAP
Wnt/Dkk Negative Feedback Regulates Sensory Organ Size in Zebrafish
SummaryCorrect organ size must involve a balance between promotion and inhibition of cell proliferation. A mathematical model has been proposed in which an organ is assumed to produce its own growth activator as well as a growth inhibitor [1], but there is as yet no molecular evidence to support this model [2]. The mechanosensory organs of the fish lateral line system (neuromasts) are composed of a core of sensory hair cells surrounded by nonsensory support cells. Sensory cells are constantly replaced and are regenerated from surrounding nonsensory cells [3], while each organ retains the same size throughout life. Moreover, neuromasts also bud off new neuromasts, which stop growing when they reach the same size [4, 5]. Here, we show that the size of neuromasts is controlled by a balance between growth-promoting Wnt signaling activity in proliferation-competent cells and Wnt-inhibiting Dkk activity produced by differentiated sensory cells. This negative feedback loop from Dkk (secreted by differentiated cells) on Wnt-dependent cell proliferation (in surrounding cells) also acts during regeneration to achieve size constancy. This study establishes Wnt/Dkk as a novel mechanism to determine the final size of an organ
Bryosphere within an Antarctic moss pillar
第6回極域科学シンポジウム分野横断セッション:[IB2] 地球環境変動の解析と地球生命システム学の構築11月19日(木) 統計数理研究所 セミナー室1(D305
cytokine profile of PFAPA
Objective : An attempt was made to identify characteristic cytokine profiles to distinguish periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPAS) from recurrent tonsillitis, of which clinical manifestations are similar to those of PFAPAS in children. Methods : Serum concentrations of IL-6, IL-4 and IFN-γ were measured during febrile episodes in pediatric patients. Results : The levels of IL-6 during febrile episodes were markedly increased above the upper limit of normal ranges in patients with both PFAPAS and recurrent tonsillitis, but there were no significant differences between groups. The levels of IL-4 during febrile episodes in PFAPAS patients were significantly lower than those in recurrent tonsillitis patients. The levels of IFN-γ during febrile episodes in PFAPAS patients were significantly higher than those in recurrent tonsillitis patients. Conclusion : In pediatric patients with PFAPAS, despite an increase of IL-6, IL-4 was suppressed with a marked increase of IFN-γ during febrile episodes. On the contrary, in febrile pediatric patients with recurrent tonsillitis, both IL-6 and IL-4, but not IFN-γ were increased. The characteristic cytokine profiles of IL-6, IL-4 and IFN-γ can be used for differential diagnosis of PFAPAS from recurrent tonsillitis in children in clinical ear, nose and throat (ENT) settings
極限環境適応における微生物ゲノムの生命情報学
第6回極域科学シンポジウム分野横断セッション:[IB2] 地球環境変動の解析と地球生命システム学の構築11月19日(木) 統計数理研究所 セミナー室1(D305
Induction of macrophage migration inhibitory factor precedes the onset of acute tonsillitis.
We investigated the serum macrophage migration inhibitory factor (MIF) levels of palmoplantar pustulosis patients, before and after the tonsillar provocation test. Higher serum MIF levels of palmoplantar pustulosis patients were decreased after the tonsillar provocation test (n=29). To confirm these phenomena, two patients with acute tonsillitis had their changes in body temperature, C-reactive protein (CRP) and serum MIF levels examined during the course of their illness. Surprisingly, increased MIF preceded fever and CRP elevation, and MIF subsequently decreased at the onset of fever and CRP elevation. Since MIF is an initiator of other proinflammatory cytokines, we suggest that the induction of MIF may precede other inflammatory conditions
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