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1.
Sex differences in attentional selection of global and local components of stimuli have been hypothesized to underlie sex differences in cognitive strategy choice. A Navon figure paradigm was employed in 32 men, 41 naturally cycling women (22 follicular, 19 luteal) and 19 users of oral contraceptives (OCs) containing first to third generation progestins in their active pill phase. Participants were first asked to detect targets at any level (divided attention) and then at either the global or the local level only (focused attention). In the focused attention condition, luteal women showed reduced global advantage (i.e. faster responses to global vs. local targets) compared to men, follicular women and OC users. Accordingly, global advantage during the focused attention condition related significantly positively to testosterone levels and significantly negatively to progesterone, but not estradiol levels in a multiple regression model including all naturally cycling women and men. Interference (i.e. delayed rejection of stimuli displaying targets at the non-attended level) was significantly enhanced in OC users as compared to naturally cycling women and related positively to testosterone levels in all naturally cycling women and men. Remarkably, when analyzed separately for each group, the relationship of testosterone to global advantage and interference was reversed in women during their luteal phase as opposed to men and women during their follicular phase. As global processing is lateralized to the right and local processing to the left hemisphere, we speculate that these effects stem from a testosterone-mediated enhancement of right-hemisphere functioning as well as progesterone-mediated inter-hemispheric decoupling. 相似文献
2.
Patrick Porcheron 《In vitro cellular & developmental biology. Animal》1991,27(6):479-482
Summary The regulation of growth and development of insects is under endocrine control and involves both juvenile hormones and ecdysteroids.
Neuropeptides are master regulators which control the secretion of these hormones. Most experiments in insect endocrinology
have been conducted in vivo, but tissue culture methodology is playing an increasing role due to the great interest in simpler
model systems for the study of complex processes that occur in vivo. The availability of appropriate media has allowed the
culture of a variety of insect organs and cell lines of defined origin which have kept certain properties of the parent tissues.
Tissue culture approaches have been useful for studying hormonal control of morphogenetic processes. Cell lines are particularly
suited to the study of hormonally regulated mechanisms of macromolecular biosynthesis and gene expression. Thus, the value
of in vitro analysis in studies of regulation of hormone production is now recognized. Results obtained from tissue culture
allow more precise definition of the hormonal requirements of insect cells and tissues for growth and differentiation and
might make possible the discovery of new growth regulators. 相似文献
3.
Jiefeng He Haichao Zhao Dongfeng Deng Yadong Wang Xiao Zhang Haoliang Zhao Zongquan Xu 《Journal of cellular physiology》2020,235(3):2464-2477
This study aimed to identify significant biomarkers related to the prognosis of liver cancer using long noncoding RNA (lncRNA)-associated competing endogenous RNAs (ceRNAs) analysis. Differentially expressed mRNA and lncRNAs between liver cancer and paracancerous tissues were screened, and the functions of these mRNAs were predicted by gene ontology and pathway enrichment analyses. A ceRNA network consisting of differentially expressed mRNAs and lncRNAs was constructed. LncRNA FENDRR and lncRNA HAND2-AS1 were hub nodes in the ceRNA network. A risk score assessment model consisting of eight genes (PDE2A, ESR1, FBLN5, ALDH8A1, AKR1D1, EHHADH, ADRA1A, and GNE) associated with prognosis were developed. Multivariate Cox regression suggested that both pathologic_T and risk group could be regarded as independent prognostic factors. Furthermore, a nomogram model consisting of pathologic_T and risk group showed a good prediction ability for predicting the survival rate of liver cancer patients. The nomogram model consisting of pathologic_T and a risk score assessment model could be regarded as an independent factor for predicting prognosis of liver cancer. 相似文献
4.
蜂蜜中内源性物质苯甲酸的研究进展 总被引:1,自引:0,他引:1
蜂蜜是一种蜜蜂采集植物花蜜后酿制而成的天然甜味物质,具有丰富营养成分和多种生理活性功能。本文明确了苯甲酸是蜂蜜中天然存在的一种特征性风味物质,且含量与蜜源植物有关,并对其检测方法、形成机理、代谢途径和稳定性等进行了概述。最后,提出应深入细化蜂蜜等食品中苯甲酸形成机理的基础研究,不仅可针对性降低加工工艺导致的含量升高,更可为传统产业科技转型升级提供技术支持。 相似文献
5.
6.
Jaap J. Beintema 《Journal of the history of biology》2008,41(1):159-165
Albert (von) Szent-Györgyi started his studies on biological oxidation processes – which also resulted in the discovery of vitamin C, for which he received the Nobel Price in 1937 – in the Laboratory of Physiology of the University in Groningen in 1922–1926. These studies were later continued in Cambridge (UK) and Szeged (Hungary). When he had already received the invitation as well as the financial means to come and work in Cambridge, he still did experiments in Groningen to find out whether the adrenal extract, isolated by him and later found to be a major source of vitamin C, contained the hormone essential for the survival of cats whose adrenals were removed. He was rather upset by the negative results of this experiment, judging by the recollections of a former student of his. This history constitutes an interesting example of the difference between serendipitous discovery and planned invention. 相似文献
7.
Priv.-Doz. Dr. Brita von Gaudecker Gerhard G. Steinmann Martin Leo Hansmann Joachim Harpprecht Novica M. Milicevic Hans Konrad Müller-Hermelink 《Cell and tissue research》1986,244(2):403-412
Summary The epithelial framework of the human thymus has been studied in parallel by immunohistochemical methods at the light- and electron-microscopic levels. Different monoclonal antibodies were used, reacting with components of the major histocompatibility complex, keratins, thymic hormones and other as yet antigenically undefined substances, which show specific immunoreactivities with human thymus epithelial cells.The electron-microscopic immunocytochemical observations clearly confirm microtopographical differences of epithelial cells not only between the thymic cortex and medulla, but also within the cortex itself. At least four subtypes of epithelial cells could be distinguished: 1) the cortical surface epithelium; 2) the main cortical epithelial cells and thymic nurse cells; 3) the medullary epithelial cells; and 4) the epithelial cells of Hassall's corpuscles.The various epithelial cell types of the thymus display several common features like tonofilaments, desmosomes and some surface antigens as demonstrated by anti-KiM3. In other respects, however, they differ from each other. The cortical subtype of thymic epithelial cells including the thymic nurse cells shows a distinct pattern of surface antigens reacting positively with antibodies against HLA-DR (anti-HLA-DR) and anti-21A62E. Electron-microscopic immunocytochemistry with these antibodies clearly reveals a surface labeling and a narrow contact to cortical thymocytes particularly in the peripheral cortical regions. An alternative staining pattern is realized by antibodies to some antigens associated with other subtypes of thymic epithelial cells. Medullary epithelial cells as well as the cortical surface epithelium react likewise positively with antibodies to special surface antigens (anti-Ep-1), to special epitopes of cytokeratin (anti-IV/82), and to thymic hormones (anti-FTS). The functional significance of distinct microenvironments within the thymus provided by different epithelial cells is discussed in view of the maturation of T-precursor cells.Glossary of Abbreviations
Anti-X
anti-X antibody
-
APUD-cells
amine precursor uptake and decarboxylation (gastro-intestinal endocrine cells)
-
DAB
diamino-benzidine
-
DMSO
dimethyl sulfoxide
-
FTS
facteur thymique sérique
-
HLA-A, B, C
human leucocyte antigen, A, B, C-region related
-
HLA-DR
human leucocyte antigen, D-region related
-
IDC
interdigitating cell
-
MHC
major histocompatibility gene complex
-
PBS
phosphate-buffered saline
-
TNC
thymic nurse cell
This investigation was supported by grants from the Deutsche Forschungsgemeinschaft, and its Sonderforschungsbereich 111Fellow of the Alexander von Humbold-Stiftung, Institute of Pathology, University of Würzburg, Federal Republic of GermanyThe authors appreciate the contribution of human thymus tissue from Professor Alexander Bernhard, Abteilung kardiovasculäre Chirurgie der Universität Kiel; the gift of monoclonal antibodies from Dr. M.J.D. Anderson, Dr. M. Dardenne and Dr. H.J. Radzun; and the excellent technical assistence of Mrs. O.M. Bracker, Mrs. H. Hansen, Mrs. R. Köpke, Mrs. M. v. Kolszynski, Mrs. J. Quitzau, Mrs. H. Siebke, and Mrs. H. Waluk 相似文献
8.
THE TIMING OF DIVISION IN CHLAMYDOMONAS 总被引:3,自引:2,他引:1
9.
Larvae and nymphs of the tick Ixodes ricinus L. display similar reactions to analogs of the insect juvenile hormones (methoprene and pyriproxyfen), which induce at both stages juvenalization of the Haller's sense organ regenerates. Similar effects were also described for retinoic acid. Unlike juvenoids, retinoic acid can affect not only regeneration, but also normal development of the Haller's organ and cause changes corresponding to so-called regenerative induction. Amputation of the leg and treatment with retinoic acid do not affect the duration of larval or nymphal development, while juvenoids somewhat accelerate their development. 相似文献
10.
Ri-Sheng Tang Jian-Chu Zheng Zhi-Qing Jin Da-Dong Zhang Yi-Hong Huang Liu-Gen Chen 《Plant Growth Regulation》2008,54(1):37-43
In order to explore the possible physiological mechanism of high temperature induced sterility in rice, we examined the floret
sterility and endogenous plant growth regulator contents in pollens of two hybrid rice cultivars Shanyou63 and Teyou559 that
are tolerant and susceptible to high temperature, respectively. Indexes of floret sterility, pollen activity, and variation
of endogenous indole-3-acetic acid (IAA), gibberellic acids (GAs), abscisic acid (ABA), free proline and soluble proteins
in anthers were measured. We found that during the course of high temperature treatment, both cultivars exhibited a marked
decrease in pollen activity, pollen germination and floret fertility; however, the high temperature tolerant Shanyou63 showed
a much slower rate of decrease than the high temperature susceptible Teyou559. In addition, anthers of both cultivars displayed
a decrease in the contents of IAA, GAs, free proline and soluble proteins but an increase in the ABA content. Yet compared
to Teyou559, Shanyou63 retained significantly higher levels of free praline and GAs and a lower level of ABA, along with higher
pollen vigour and pollen germination rate even after prolonged high temperature treatment. Our study suggests a possible correlation
between pollen viability/floret sterility and high temperature-caused changes in IAA, GAs, ABA, free proline and soluble protein
contents. The severity in these changes may reflect the variation of rice cultivars in their heat stress sensitivities for
floret development. 相似文献