bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development, molecular composition and freeze tolerance of bovine embryos cultured in TCM-199 supplemented with hyaluronan
Authors: Palasz A.T. , Breña P. Beltrán , Martinez Marcelo F. , Perez-Garnelo S.S. , Ramirez M.A. , Gutiérrez-Adán A. , De la Fuente J. 
Published: January 2008

SummaryHyaluronan (HA) is glycosaminoglycan that is present from the start of embryonic development and its role and concentration increases with embryo development. The objective of this study was to evaluate if the presence of HA in TCM-199 culture medium had an effect on the development and quality of bovine embryos. There was no effect of HA on the total number of zygotes developing to blastocysts on day 7, however more expanded and hatched blastocyst stages were observed on days 8 and 9 in the group supplemented with HA (p< 0.05). Following freeze/thawing, significantly more (p< 0.05) embryos cultured in medium supplemented with HA hatched than those cultured in TCM-199 alone or those with BSA. Medium supplemented with HA and BSA significantly increased the level of expression of glucose metabolismGlut-1gene and embryo compactionCx43gene (p< 0.05), and had no effect onGlut-5andIGF-IIexpression. In addition, HA presence in culture decreased the level of expression of apoptosisBaxand oxidative stressSOXgenes (p< 0.05). There was significant difference in total number of nuclei between TCM-199 medium only and the remaining media containing BSA or HA plus BSA, between which there was no difference. In summary, our results indicate that the addition of high molecular weight HA to TCM-199 medium that contains BSA on day 4 of culture improved embryo development to hatching and hatched blastocysts and the quality of produced embryos, which were superior to embryos cultured without HA addition.
Viability, acrosome morphology and fertilizing capacity of boar spermatozoa treated with strontium chloride
Authors: Okada Konosuke , Palmieri Chiara , Salda Leonardo Della , Vackova Irena 
Published: January 2008

SummaryThe positive effect of strontium ions (Sr2+) on sperm motility, capacitation and acrosome reaction has been demonstrated in the mouse, human, guinea pig and hamster. In the present study, we have evaluated the effect of Sr2+ on the viability and acrosome morphology of boar spermatozoa, and on the fertilization and development after the microinjection of Sr2+-treated spermatozoa into porcine oocytes. Before incubation, 79% of spermatozoa were classified as propidium iodide (PI)-negative (live) using the LIVE/DEAD Sperm Viability Kit. After incubation with strontium chloride (SrCl2), 39% (0 mM; no divalent cations), 25% (1.9 mM) and 24% (7.5 mM) of them were classified as PI-negative. The proportion of spermatozoa that had initiated the acrosome reaction was higher in Sr2+-containing medium than in Sr2+-free medium, when assessed by electron microscopy. There was no significant difference in percentage of spermatozoa initiating the acrosome reaction between Sr2+-treated groups (1.9 mM: 22%, 7.5 mM: 33%, p > 0.05). After the microinjection of spermatozoa incubated with SrCl2, 67% (1.9 mM) and 61% (7.5 mM) of injected oocytes were successfully fertilized, and then 43% (1.9 mM) and 41% (7.5 mM) contained a fully decondensed sperm head. Sham-injected oocytes were significantly activated at a lower rate than Sr2+-treated groups (27%, p < 0.05). Next, after microinjection of spermatozoa incubated with 1.9 mM SrCl2 (n = 51), 45% of injected oocytes cleaved on day 2, and 18% developed to blastocysts on day 7 (sham-injection, n = 48: 15% to cleavage and 0% to blastocyst). These results demonstrate that Sr2+ is likely to positively affect the fertilizing capacity of spermatozoa in the pig.
5-HT-receptive structures are localized in the interblastomere cleft ofParacеntrotus lividusearly embryos
Authors: Shmukler Yu. B. , Silvestre Francesco , Tosti Elisabetta 
Published: January 2008

SummaryLocal application of the agonists of serotonin receptors of third type 5-HTQ, SR57277A and quipazine into the interblastomere cleft of the sea urchinParacentrotus lividusembryo during first cleavage division, evokes specific membrane currents, whereas application of these drugs out of contact area show currents of lower amplitude and longer latent period. At the same time 5-HT3-receptor agonist quipazine imitates interblastomere signal in half embryos, but corresponding antagonists prevent it. Present data develop the hypothesis of protosynapse, demonstrating that the distribution of membrane serotonin receptors is limited to the period of cleavage division and localized in the interblastomere contact area. A possible role of spatial–temporal restriction of receptors at the interblastomere contact area is discussed in relation to the subsequent embryo development.
Modulators of Bufo arenarum ovulation
Authors: Ramos Inés , Cisint Susana B. , Crespo Claudia A. , Medina Marcela F. , Fernández Silvia N. 
Published: January 2008

SummaryIn this study we investigated ovulation in vitro using ovary samples from Bufo arenarum with respect to their response to stimulation with homologous pituitary homogenate (HPH) or with progesterone and prostaglandins (PGF2α and PGE1) as intermediates of pituitary action. Ovary samples were obtained from animals captured during the breeding period. Our results demonstrate that the ovulatory response to all different inducers was dose dependent, the highest percentage of ovulated oocytes being obtained with HPH treatment. An important increase in the ovulatory response was obtained by the association of PGF2α with either HPH or progesterone at suboptimal doses, indicating that this prostaglandin induced a synergistic potentiating effect. Incubation with cyclooxygenase inhibitors (indomethacin or diclofenac sodium) produced a significant decrease in the ovulation induced by HPH, demonstrating that prostaglandins are involved in the action of the pituitary gland in this process. According to our results, PGE1 not only had no participation in the ovulatory process, but also produced an inhibitory effect on ovulation induced by HPH treatment.
Developmental rate and allocation of transgenic cells in rabbit chimeric embryos
Authors: Chrenek P. , Makarevich A.V. , Bauer M. , Jurcik R. 
Published: January 2008

SummaryThe objective of this study was to compare developmental capacity of rabbit chimeric embryos and the allocation of the EGFP gene expression to the embryoblast (ICM) or embryonic shield. We produced chimeric embryos (TR<>N) by synchronous transfer of two or three blastomeres at the 16-cell stage from transgenic (TR) into normal host embryos (N) at the same stage. In the control group, two to three non-transgenic blastomeres were used to produce chimeric embryos. The TR embryos were produced by microinjection of EGFP into both pronuclei of fertilized rabbit eggs. The developmental rate and allocation of EGFP-positive cells of the reconstructed chimeric embryos was controlled at blastocyst (96 h PC) and embryonic shield (day 6) stage.All chimeric embryos (120/120, 100%) developed up to blastocyst stage. Using fluorescent microscope, we detected green signal (EGFP expression). In 90 chimeric (TR<>N) embryos (75%). Average total number of cells in chimeric embryos at blastocyst stage was 175 ± 13.10, of which 58 ± 2.76 cells were found in the ICM area. The number of EGFP-positive cells in the ICM area was 24 ± 5.02 (35%). After the transfer of 50 chimeric rabbit embryos at the 16-cell stage, 20 embryos (40%) were flushed from five recipients on day 6 of pregnancy, of which five embryos (25%) were EGFP positive at the embryonic shield stage.Our results demonstrate that transgenic blastomeres in synchronous chimeric embryos reconstructed from TR embryos have an ability to develop and colonize ICM and embryonic shield area.
Full term development of normal mice after transfer of IVF embryos derived from oocytes stored at room temperature for 1 day
Authors: Lei Zi-Li , Huang Jun-Cheng , Shi Li-Hong , Miao Yi-Liang , Nan Chang-Long , Yang Ji-Wen , OuYang Ying-Chun , Sun Qing-Yuan , Chen Da-Yuan 
Published: January 2008

SummaryEarly studies have shown that some mouse cumulus–oocyte complexes (COCs) stored at room temperature for 24 h still retained full developmental potential. In this study, we stored denuded mouse oocytes (DOs) at room temperature (25 °C) for 24 h and activated these oocytes with 10 mM SrCl2 or fertilized the oocytes by IVF. We found that nearly half of the DOs stored at room temperature for 1 day can be fertilized normally by IVF and that two foster mothers gave birth to seven pups. Embryos from stored oocytes were cultured in CZB medium with or without 1 μg/ml 17β-estradiol (E2). The numbers of embryo that developed to morula/blastocyst stage after parthenogenetic activation and IVF were significantly increased when E2 was added to the culture (p < 0.05). These results suggest that E2 might improve mouse embryo development in vitro. The birth of seven agouti pups and their healthy growth indicated that the storage of DOs at room temperature for 1 day may be a practical procedure for mammalian reproduction.
Review of: Tumour invasion and metastasis initiated by microRNA-10b in breast cancer
Authors: Swarbrick Alex 
Published: January 2008

Citation of the original article:L. Ma, J. Teruya-Feldstein, R. A. Weinberg. Nature 2007; 449(7163): 682–688; Epub 26 September 2007.Abstract of the original article:MicroRNAs have been implicated in regulating diverse cellular pathways. Although there is emerging evidence that some microRNAs can function as oncogenes or tumour suppressors, the role of microRNAs in mediating cancer metastasis remains unexplored. Here we show, using a combination of mouse and human cells, that microRNA-10b (miR-10b) is highly expressed in metastatic breast cancer cells and positively regulates cell migration and invasion. Overexpression of miR-10b in otherwise non-metastatic breast tumours initiates robust invasion and metastasis. Expression of miR-10b is induced by the transcription factor Twist, which binds directly to the putative promoter of miR-10b (MIRN10B). The miR-10b induced by Twist proceeds to inhibit translation of the messenger RNA encoding homeobox D10, resulting in increased expression of a well-characterized pro-metastatic gene, RhoC. Significantly, the level of miR-10b expression in primary breast carcinomas correlates with clinical progression. These findings suggest the workings of an undescribed regulatory pathway, in which a pleiotropic transcription factor induces expression of a specific microRNA, which suppresses its direct target and in turn activates another pro-metastatic gene, leading to tumour cell invasion and metastasis.
Pre-race warm-up practices in Greyhound racing: a pilot study
Authors: Windred A J , Osmotherly P G , McGowan C M 
Published: January 2008

AbstractDespite the high athletic demands of Greyhound racing and recommendations for the inclusion of pre-race warm-up by some veterinarians, the extent of warm-up practices by Greyhound owners and trainers remains unexplored. We postulated that little pre-race warm-up occurred and any warm-up activities were performed at random. A cross-sectional study design was used to examine pre-race warm-up practices in a sample of 80 Greyhounds. Warm-up components were recorded and scores were assigned in order to quantify the total amount of warm-up undertaken. Associations between total warm-up and signalment and race characteristics were analysed statistically. Correlations between total warm-up performed and all variables including race distance, race order, grade of Greyhound and trainer were poor (all r < 0.2). No statistically significant association between total warm-up and any variable examined could be demonstrated at the P = 0.05 level, although a weak trend towards graded Greyhounds performing more warm-up was noted (P = 0.09). We conclude that little pre-race warm-up is performed in Greyhounds and that when practised, the amount and methods of warm-up are inconsistently applied.
MIGRATION AND SOCIAL STRATIFICATION
Authors: Jaynes Gerald D. 
Published: January 2008

AbstractThe dawn of the twenty-first century confronts Western democracies with a racialized class problem. The globalization of capitalism—mass geographic movement of peoples, capital, and markets on scales unprecedented since the Atlantic slave trade—has brought poor migrants into affluent nations. Migrants' descendants are replicating conditions associated with poor Blacks. Affluent Western democracies are hurtling toward biplural stratification defined by a multiracial underclass. Racialized class stratification stems from economic policies. Capitalist democracies' edifice of social policies—sanctioning expectations of rising prosperity, welfare “safety nets” for minimal consumption, low-wage migration policies—erroneously assumed that jobs and wages would continuously grow to absorb expanding populations. Overuse of low-wage migration policies commodified work relations in low-skilled jobs. Acculturated to demand affluent living standards and egalitarian human relations, educationally deprived descendants of migrants find commodified work regimens repellent. Despite large populations of jobless natives, some maintain that affluent democracies need more migrants to do the jobs that natives won't do. But jobless youth are alienated and prone to agency, as riots in England, the United States, and, more recently, France and other areas of Europe suggest. To avert the solidification of biplural societies, social policy must slow rates of migration from low living-standard economies, expand minimum wages and income transfers to working-citizen households, and provide documented immigrants clear avenues to citizenship. This agenda is more likely to succeed in the United States, where minority voting strength is gathering considerable momentum.
IMMIGRATION AND THE FUTURE OF BLACK POWER IN U.S. CITIES
Authors: Kaufmann Karen M. 
Published: January 2008

AbstractAs a result of urban immigration and White flight over the past three decades, the demography of U.S. cities has changed rather dramatically; approximately one-half of the largest hundred cities are now composed of minority majorities. Many urban scholars expected these demographic shifts to enhance the prospects for minority electoral alliances. In reality, however, few such alliances have emerged. This paper looks to explore the barriers to effective coalition building between native-born African Americans and their immigrant counterparts. In the first half of the paper, I explore the psychological barriers to mass coalitions, focusing on the negative stereotypes and perceived zero-sum conflict that exist between native-born African Americans and Latino immigrants. The second half of the paper argues that material and symbolic incentives fuel ongoing competition between Blacks and Latinos in the political sphere. The paper concludes with a discussion of how immigrant-induced diversity coupled with existing racial hierarchies work against future Black empowerment. Even when changing urban demography makes Whites a numerical minority, White voters often retain their status as urban power players through their ability to divide minority voters at the polls. Divisive electoral strategies that offer political rewards to one group at the expense of others threaten Black incorporation in the urban arena. Unless minority leadership changes the incentive structure embedded in the traditional modes of municipal governance, Whites will persist in their economic dominance, while disadvantaged immigrants and Blacks will continue to make political choices that yield small, short-term rewards at the expense of greater social and economic justice.
BECOMING ETHNIC OR BECOMING AMERICAN?
Authors: Zhou Min , Lee Jennifer 
Published: January 2008

AbstractAs the new second generation comes of age in the twenty-first century, it is making an indelible imprint in cities across the country, compelling immigration scholars to turn their attention to this growing population. In this essay, we first review the extant literature on immigrant incorporation, with a particular focus on the mobility patterns of the new second generation. Second, we critically evaluate the existing assumptions about the definitions of and pathways tosuccessandassimilation. We question the validity and reliability of key measures of social mobility, and also assess the discrepancy between the “objective” measures often used in social science research and the “subjective” measures presented by members of the second generation. Third, we examine the identity choices of the new second generation, focusing on how they choose to identify themselves, and the mechanisms that underlie their choice of identities. We illuminate our review with some preliminary findings from our ongoing qualitative study of 1.5- and second-generation Mexicans, Chinese, and Vietnamese in Los Angeles. In doing so, we attempt to dispel some myths about group-based cultures, stereotypes, and processes of assimilation.
MULTICULTURALISM GOES IMPERIAL
Authors: Kim Claire Jean 
Published: January 2008

AbstractAs Latino and Asian immigrant populations in the United States continue to grow, controversies are cropping up over immigrant animal practices such as horse tripping in Mexicancharreadas(rodeos) and the slaughter of animals in the live-animal markets of San Francisco's Chinatown. Immigrant advocates read these controversies through a multiculturalist interpretive framework that constructs animal advocates as agents of an ethnocentric and racist majority. In this article, I argue that this multiculturalist interpretation tends to “go imperial” by mischaracterizing the position(s) of animal advocates and invalidating and suppressing the other, potentially competitive, moral discourse at play: the discourse about cruelty toward animals. I explicate this suppressed discourse and then propose the development of a mutually challenging and potentially edifying moral dialogue in which majority and minority animal practices are simultaneously open to scrutiny and criticism. Clashes over customary practices can aggravate intergroup tensions, but they also have the potential to lead to meaningful moral dialogue between the majority and immigrant minorities.
MOVING STORIES
Authors: Suárez-Orozco Marcelo , Suárez-Orozco Carola 
Published: January 2008

AbstractIn the first decade of the new millennium, a new cycle of public concern about the benefits and harms of immigration has erupted. The harsh spotlight on undocumented immigration and border controls has blinded us to many important facets of the problem. In this article, we focus on the experience and integration of the children of immigrants. These youth are the largest growing segment of the U.S. child population—now constituting 20% of our nation's children and projected by the year 2040 to make up one-third of our children. Immigrant-origin youth are extraordinarily diverse, and their experiences resist facile generalizations. The social and educational outcomes of immigrant youth will thus vary substantially depending upon the specific constellation of resources and the settlement context. Of critical importance is how immigrant youth fare academically, as this has long-term implications for their future, as well as our society's well-being. While some are successfully navigating the U.S. educational system, large numbers struggle academically, leaving school without having acquired the tools that will enable them to function in the highly competitive labor market and ever more complex society. Here we explore a variety of factors that shed light on the educational integration of the children of immigrants: educational background; poverty; segregation; undocumented status; English-language acquisition; promoting academic engagement; family relations; peer relationships; communities and community organizations; and mentoring relationships. We advocate a major new policy agenda to ease the transition of America's newest and littlest arrivals to their new home.
Influence of turbulence on the shape of a spectral line: the analytical approach
Authors: Silant'ev N. A. , Lekht E. E. , Mendoza-Torres J. E. , Rudnitskij G. M. 
Published: January 2008

AbstractWe consider the propagation of spectral-line radiation in a correlated turbulent atmosphere. The ensembles of turbulent velocities u(r,t) and optical depths, τν, are assumed to be Gaussian. We investigate the explicit analytical solution of the stochastic radiative transfer equation for the intensity Iν of radiation. The scattering term is not taken into account. It is shown that, in addition to the usual Doppler broadening of the spectral line, correlated turbulent motions of atoms and molecules give rise to considerable changes in the shape of a spectral line. We find that the mean intensity I(0)ν (Iν=I(0)ν+I′ν, I′ν = 0) obeys the usual radiative transfer equation with renormalized extinction factor αeffν if the correlation length R0 of the turbulence is small as compared to a photon free path. A simple analytical expression for αeffν is given. This expression integrally depends on the two-point correlation function of the turbulent velocity field.
Short-term variations in Class I methanol masers?
Authors: Pratap Preethi , Strelnitski Vladimir , Hoffman Samantha , Lemonias Jenna 
Published: January 2008

AbstractClass I methanol masers are found near regions of high-mass star formation and are pumped by collisions. Some indication of long-term variability in these masers has previously been reported (Kurtz et al. 2004). Here we will present evidence for variations in the intensity of the Class I methanol masers at 44 GHz on much shorter timescales. We present preliminary results of the observation of the 44 GHz Class I methanol transition toward sources in the DR21 region that indicates variability on timescales of days to possibly hours.
A review of maser polarization and magnetic fields
Authors: Vlemmings W. H. T. 
Published: January 2008

AbstractThrough polarization observations masers are unique probes of the magnetic field in a variety of different astronomical objects, with the different maser species tracing different physical conditions. In recent years maser polarization observations have provided insights in the magnetic field strength and morphology in, among others, the envelopes around evolved stars, Planetary Nebulae (PNe), massive star forming regions and supernova remnants. More recently, maser observations have even been used to determine the magnetic field in megamaser galaxies. This review will present an overview of maser polarization observations and magnetic field determinations of the last several years and discuss the implications of the magnetic field measurements for several important fields of study, such as aspherical PNe creation and massive star formation.