Between 1941 and 1963, Aaron Copland made four government-sponsored tours of Latin America that drew extensive attention at home and abroad. Interviews with eyewitnesses, previously untapped Latin ...American press accounts, and Copland’s diaries inform Carol A. Hess’s in-depth examination of the composer’s approach to cultural diplomacy. As Hess shows, Copland’s tours facilitated an exchange of music and ideas with Latin American composers while capturing the tenor of United States diplomatic efforts at various points in history. In Latin America, Copland’s introduced works by U.S. composers (including himself) through lectures, radio broadcasts, live performance, and conversations. Back at home, he used his celebrity to draw attention to regional composers he admired. Hess’s focus on Latin America’s reception of Copland provides a variety of outside perspectives on the composer and his mission. She also teases out the broader meanings behind reviews of Copland and examines his critics in the context of their backgrounds, training, aesthetics, and politics.
Estrogens in Male Physiology Cooke, Paul S; Nanjappa, Manjunatha K; Ko, CheMyong ...
Physiological reviews,
07/2017, Letnik:
97, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Estrogens have historically been associated with female reproduction, but work over the last two decades established that estrogens and their main nuclear receptors (ESR1 and ESR2) and G ...protein-coupled estrogen receptor (GPER) also regulate male reproductive and nonreproductive organs. 17β-Estradiol (E2) is measureable in blood of men and males of other species, but in rete testis fluids, E2 reaches concentrations normally found only in females and in some species nanomolar concentrations of estrone sulfate are found in semen. Aromatase, which converts androgens to estrogens, is expressed in Leydig cells, seminiferous epithelium, and other male organs. Early studies showed E2 binding in numerous male tissues, and ESR1 and ESR2 each show unique distributions and actions in males. Exogenous estrogen treatment produced male reproductive pathologies in laboratory animals and men, especially during development, and studies with transgenic mice with compromised estrogen signaling demonstrated an E2 role in normal male physiology. Efferent ductules and epididymal functions are dependent on estrogen signaling through ESR1, whose loss impaired ion transport and water reabsorption, resulting in abnormal sperm. Loss of ESR1 or aromatase also produces effects on nonreproductive targets such as brain, adipose, skeletal muscle, bone, cardiovascular, and immune tissues. Expression of GPER is extensive in male tracts, suggesting a possible role for E2 signaling through this receptor in male reproduction. Recent evidence also indicates that membrane ESR1 has critical roles in male reproduction. Thus estrogens are important physiological regulators in males, and future studies may reveal additional roles for estrogen signaling in various target tissues.
Estrogens have traditionally been considered female hormones. Nevertheless, the presence of estrogen in males has been known for over 90 years. Initial studies suggested that estrogen was deleterious ...to male reproduction because exogenous treatments induced developmental abnormalities. However, demonstrations of estrogen synthesis in the testis and high concentrations of 17β-estradiol in rete testis fluid suggested that the female hormone might have a function in normal male reproduction. Identification of estrogen receptors and development of biological radioisotope methods to assess estradiol binding revealed that the male reproductive tract expresses estrogen receptor extensively from the neonatal period to adulthood. This indicated a role for estrogens in normal development, especially in efferent ductules, whose epithelium is the first in the male reproductive tract to express estrogen receptor during development and a site of exceedingly high expression. In the 1990s, a paradigm shift occurred in our understanding of estrogen function in the male, ushered in by knockout mousemodels where estrogen production or expression of its receptors was not present. These knockout animals revealed that estrogen's main receptor (estrogen receptor 1 ESR1) is essential for male fertility and development of efferent ductules, epididymis, and prostate, and that loss of only the membrane fraction of ESR1 was sufficient to induce extensive male reproductive abnormalities and infertility. This review provides perspectives on the major discoveries and developments that led to our current knowledge of estrogen's importance in the male reproductive tract and shaped our evolving concept of estrogen's physiological role in the male. Summary Sentence Estrogenic activity, which was first thought to be harmful to males, has now been shown to be produced locally in significant quantities and to be essential for male reproductive tract development and fertility.
Oestrogens and spermatogenesis Carreau, Serge; Hess, Rex A.
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
05/2010, Letnik:
365, Številka:
1546
Journal Article
Recenzirano
Odprti dostop
The role of oestrogens in male reproductive tract physiology has for a long time been a subject of debate. The testis produces significant amounts of oestrogenic hormones, via aromatase, and ...oestrogen receptors (ERs)α (ESR1) and ERβ (ESR2) are selectively expressed in cells of the testis as well as the epididymal epithelium, depending upon species. This review summarizes the current knowledge concerning the presence and activity of aromatase and ERs in testis and sperm and the potential roles that oestrogens may have in mammalian spermatogenesis. Data show that physiology of the male gonad is in part under the control of a balance of androgens and oestrogens, with aromatase serving as a modulator.
Critical limb ischemia (CLI), the most severe form of peripheral artery disease, is characterized by pain at rest and non‐healing ulcers in the lower extremities. For patients with CLI, where the ...extent of atherosclerotic artery occlusion is too severe for surgical bypass or percutaneous interventions, limb amputation remains the only treatment option. Thus, cell‐based therapy to restore perfusion and promote wound healing in patients with CLI is under intense investigation. Despite promising preclinical studies in animal models, transplantation of bone marrow (BM)‐derived cell populations in patients with CLI has shown limited benefit preventing limb amputation. Early trials injected heterogenous mononuclear cells containing a low frequency of cells with pro‐vascular regenerative functions. Most trials transferred autologous cells damaged by chronic disease that demonstrated poor survival in the ischemic environment and impaired function conferred by atherosclerotic or diabetic co‐morbidities. Finally, recent preclinical studies suggest optimized blood vessel formation may require paracrine and/or structural contributions from multiple progenitor cell lineages, angiocrine‐secretory myeloid cells derived from hematopoietic progenitor cells, tubule‐forming endothelial cells generated by circulating or vessel‐resident endothelial precursors, and vessel‐stabilizing perivascular cells derived from mesenchymal stem cells. Understanding how stem cells co‐ordinate the myriad of cells and signals required for stable revascularization remains the key to translating the potential of stem cells into curative therapies for CLI. Thus, combination delivery of multiple cell types within supportive bioengineered matricies may represent a new direction to improve cell therapy strategies for CLI. Stem Cells 2018;36:161–171
Pro‐vascular progenitor cell “exhaustion” in patients with critical limb ischemia (CLI). The human bone marrow microenvironment is a rich reservoir of progenitor cells involved in blood vessel homeostasis and repair. Early myeloid hematopoietic progenitor cells secrete angiocrine signals that stimulate and direct angiogenesis. Circulating and vessel‐resident endothelial precursor cells act as the building blocks of blood vessels and inosculate into the vessel wall during vasculogenesis. Multipotent mesenchymal stromal cells (also known as mesenchymal stem cells or MSC) generate vessel wrapping pericytes and smooth muscle cells that stabilize newly formed vessels and act as “conductors of the orchestra” to recruit and co‐ordinate the functions of accessory cells (M2 macrophages) implicated in arteriogenic remodeling and activation of collateral vessel perfusion. Unfortunately, in CLI patients with diabetes with atherosclerotic co‐morbidities, chronic exposure to oxidative stress, systemic inflammation, lipotoxicity, and glucose toxicity result in regenerative cell depletion and dysfunction within the stem cell pool.
The properties of the polarity inversion line (PIL) in solar active regions (ARs) are strongly correlated to flare occurrences. The PIL mask, enclosing the PIL areas, has shown significant potential ...for improving machine-learning-based flare prediction models. In this study, an unsupervised machine-learning algorithm, Kernel Principle Component Analysis (KPCA), is adopted to directly derive features from the PIL mask and difference PIL mask, and use those features to classify ARs into two categories-non-strong flaring ARs and strong-flaring (M-class and above flares) ARs-for time-in-advance from one hour to 72 hr at a 1 hr cadence. The two best features are selected from the KPCA results to develop random-forest classifiers for predicting flares, and the models are then evaluated and compared to similar models based on the R value and difference R value. The results show that the features derived from the PIL masks by KPCA are effective in predicting flare occurrence, with overall better Fisher ranking scores and similar predictive statistics as the R value characteristics.
Spermiogenesis is the longest phase of spermatogenesis, with dramatic morphological changes and a final step of spermiation, which involves protein degradation and the removal of excess cytoplasm; ...therefore, we hypothesized that macroautophagy/autophagy might be involved in the process. To test this hypothesis, we examined the function of ATG5, a core autophagy protein in male germ cell development. Floxed Atg5 and Stra8− iCre mice were crossed to conditionally inactivate Atg5 in male germ cells. In Atg5
flox/flox
; Stra8− iCre mutant mice, testicular expression of the autophagosome marker LC3A/B-II was significantly reduced, and expression of autophagy receptor SQSTM1/p62 was significantly increased, indicating a decrease in testicular autophagy activity. The fertility of mutant mice was dramatically reduced with about 70% being infertile. Sperm counts and motility were also significantly reduced compared to controls. Histological examination of the mutant testes revealed numerous, large residual bodies in the lumen of stages after their normal resorption within the seminiferous epithelium. The cauda epididymal lumen was filled with sloughed germ cells, large cytoplasmic bodies, and spermatozoa with disorganized heads and tails. Examination of cauda epididymal sperm by electron microscopy revealed misshapen sperm heads, a discontinuous accessory structure in the mid-piece and abnormal acrosome formation and loss of sperm individualization. Immunofluorescence staining of epididymal sperm showed abnormal mitochondria and acrosome distribution in the mutant mice. ATG5 was shown to induce autophagy by mediating multiple signals to maintain normal developmental processes. Our study demonstrated ATG5 is essential for male fertility and is involved in various aspects of spermiogenesis.
Abbreviations: AKAP4: a-kinase anchoring protein 4; ATG5: autophagy-related 5; ATG7: autophagy-related 7; ATG10: autophagy-related 10; ATG12: autophagy-related 12; cKO: conditional knockout; DDX4: DEAD-box helicase 4; MAP1LC3/LC3/tg8: microtubule-associated protein 1 light chain 3; PBS: phosphate-buffered saline; PIWIL2/MILI: piwi like RNA-mediated gene silencing 2; RT-PCR: reverse transcription-polymerase chain reaction; SQSTM1/p62: sequestosome 1; TBC: tubulobulbar complexes; WT: wild type.
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