307 research outputs found
Sex and age-dependent effects of a maternal junk food diet on the mu-opioid receptor in rat offspring
No full textAbstract not availableJessica R. Gugusheff, Sung Eun Bae, Alexandra Rao, Iain J. Clarke, Lucilla Poston, Paul D. Taylor, Clive W. Coen, Beverly S. Muhlhausle
Humor chrześcijanina w relacji do innych wartości w świetle twórczości Gilberta Keitha Chestersona i Clive’a Staplesa Lewisa
No full textBased on the work of Gilbert Keith Chesterton and Clive Staples Lewis, the author analyzes the role of humor in the Christian spirituality and the connection between humor and other values such as love, humility, freedom and truth. One of the conclusions is that both writers regarded and showed humor as an indicator, of the authenticity and depth are lived and realized in the above mentioned values.Na podstawie twórczości Gilberta Keitha Chestertona i Clive’a Staplesa Lewisa autor analizuje rolę humoru w duchowości chrześcijanina i związek humoru z wybranymi wartościami: pokorą, miłością, wolnością i prawdą. Jednym z wniosków jest ten, że obaj tytułowi pisarze uważali i ukazywali humor jako rodzaj indykatora, który wskazuje, z jaką autentycznością i głębią są przeżywane i realizowane wymienione wartości
Reproductive inhibition in female common and highveld mole-rats: neuroanatomical and neuroendocrine perspectives
No full textThesis (PhD)--University of Pretoria, 2005.The social reproductive inhibition evident in female common (Cryptomys hottentotus hottentotus) and highveld (Cryptomys hottentotus pretoriae) mole-rats was investigated, focussing on intra- and inter-subspecies differences in gonadotropin¬releasing hormone (GnRH) neuroanatomy and neuroendocrinology and potential mechanisms mediating social infertility through the suppression of luteinizing hormone (LH) and/or GnRH synthesis or release. The molecular structure of the GnRH peptide present in highveld mole-rat tissue was determined. Messenger ribonucleic acid (mRNA) coding for GnRH was isolated from hypothalamic tissue of a female highveld mole-rat. The nucleotide sequence of the transcribed complimentary deoxyribonucleic acid (cDNA) predicts amino acid sequences that indicate a potential polymorphism in the mature peptide. These sequences differ from classic 'mammalian' GnRH by either one or two amino acid positions. One form of mole-rat GnRH is identical to the unique GnRH expressed by guinea pigs, while the second form differs from guinea pig GnRH in one amino acid position. These results indicate that classic 'mammalian' GnRH is not the chief structural form of GnRH in the mole-rat. In both the common and highveld mole-rat, GnRH structures were loosely distributed along the septo-preoptico-infundibular pathway. Highveld mole-rats consistently had more GnRH cell bodies and higher levels of the peptide than common mole-rats. The subspecies also differed with regards to the relative distribution of GnRH cell bodies in the preoptic area and the medio-basal hypothalamus. Reproductive status and season did not influence GnRH neuroanatomy (numbers and morphology of cell bodies, distribution of GnRH structures and density of GnRH staining in the median eminence) or endogenous brain GnRH content in male or female common mole-rats. Likewise reproductive and non-reproductive male highveld mole-rats did not differ with regards to the GnRH neuroanatomical and neuroendocrinological parameters investigated. Dominant and subordinate female highveld mole-rats had similar numbers of GnRH cell bodies, and did not differ with regards to the distribution of GnRH structures. Brain GnRH levels was however significantly lower in reproductive females compared to non-reproductive females. Similarly, GnRH staining in the median eminence was significantly less intense in reproductive compared to non-reproductive females, indicating reduced release in the latter. Excess peptide most likely accumulates in the nerve terminals and the cell bodies. Endogenous opioid peptides (EOPs) are tentatively considered to playa role in the socially-induced infertility in non-reproductive female highveld mole-rats. Intact reproductive females and intact and ovariectmized non-reproductive females were treated with the opioid antagonist naloxone, alone and in different combinations with exogenous GnRH, to establish the role of EOPs and gonadal hormones in the reduced GnRH release evident in subordinate female highveld mole-rats. Naloxone treatment failed to alter plasma LH levels in any of the intact groups, while ovariectomized non-reproductive females showed a significant response. The pituitary response to a GnRH challenge was not influenced by either a single naloxone administration or longer term naloxone-priming regimens. In the absence of the negative feedback effects of gonadal steroids following ovariectomy, non¬reproductive females showed GnRH-chalienged plasma LH levels similar to that seen in intact reproductive females, both being significantly higher compared to intact non-reproductive females. Steroid-dependent mechanisms altering GnRH secretion and/or pituitary sensitivity to the endogenous peptide may therefore playa role in the social reproductive regulation displayed by the highveld mole-rat. EOPs may be indirectly involved in steroid negative feedback suppression of GnRH. In conclusion, the GnRH neuroanatomy and neuroendocrinology of female common mole-rats provide no evidence for a physiological component to the behavioural reproductive restraint in subordinate females due to incest avoidance. Non¬reproductive female highveld mole-rats are, however, temporarily infertile due to pituitary insensitivity to GnRH coupled with suppressed hypothalamic GnRH release potentially mediated by steroid-dependent mechanisms.Zoology and Entomologyunrestricte
The reproductive biology of the solitary Cape mole-rat, Georychus capensis and the social Natal mole-rat, Cryptomys hottentotus natalensis (Rodentia : Bathyergidae)
Get PDFThesis (PhD)--University of Pretoria, 2008.The seasonality of wild caught Cape mole-rats was investigated, focusing on endocrine, neuroendocrine and neuroanatomical parameters. The Cape mole-rat reproduces only during the winter rainfall period of the western Cape Province. Interestingly, the gonadal steroid hormones do not show any significant seasonal patterns in either males or females. In addition, the pituitary does not exhibit a reduced sensitivity to GnRH stimulation during the non-breeding season in either sex. Moreover, in the brain the distribution, number and size of GnRH perikarya do not differ with respect to season. Therefore, although only producing young during a specific period of the year, the Cape mole-rat does not appear to be physiologically repressed from reproducing throughout the year. The results of this study imply that the Cape mole-rat is an opportunistic breeder that is reproductively quiescent during the dry season as a consequence of ecological factors such as lack of favourable burrowing conditions and that when opportunities avail themselves following aseasonal rainfall, reproduction may occur. The seasonality and socially induced infertility of the Natal mole-rat was examined via endocrine, neuroendocrine and neuroanatomical investigations. In contrast with the phylogenetically closely related common mole-rat and highveld mole-rat, the Natal mole-rat does not appear to breed seasonally. Post-mortem examination of animals collected revealed pregnant reproductive females throughout the year. A similar scenario is reflected in gonadal steroid concentrations, with no major seasonal differences observed in either males or females. Likewise, pituitary sensitivity to GnRH does not change over season in males or females, and all neuroanatomical parameters investigated remained stable over season in both males and females. Natal mole-rats captured for this study occur in an area with a high annual rainfall, (almost double that of the common mole-rat habitat and one and a half times that of the highveld mole-rat) and the relatively higher rainfall and hence soil moisture content may provide the Natal mole-rat with increased foraging time a result of increased periods over which the soil is optimal for burrowing. Socially induced infertility in the Natal mole-rat appears to be enforced behaviourally as a result of active incest avoidance. The circulating testosterone concentrations were not significantly different in reproductive and non-reproductive males, and likewise oestrogen concentrations did not differ between reproductive and non-reproductive females. Progesterone concentrations were very low in subordinate females, but markedly higher in reproductive females. This is not surprising since the Natal mole-rat is an induced ovulator, thus coitus is required to induce the LH surge that stimulates ovulation. The sensitivity of the pituitary to a GnRH challenge did not differ between reproductive and non-reproductive animals from either sex. No neuroanatomical differences were observed between reproductive and non-reproductive animals of either sex, however, non-reproductive males and females had significantly higher amounts of GnRH in the median eminence, implying that GnRH is synthesized and transported to the median eminence but not released in the portal system to the anterior pituitary. These findings suggest that non-reproductive animals of both sexes are not sterile, but merely sexually quiescent. CopyrightZoology and Entomologyunrestricte
60 Years of Neuroendocrinology::Celebrating the brain's other output-input system and the monograph that defined neuroendocrinology
No full textThe brain's unimaginably complex operations are expressed in just two types of output: muscle activity and hormone release. These are the means by which the brain acts beyond its bony casing. Muscle-mediated actions (such as speaking, writing, pupillary reflexes) send signals to the outside world that may convey thoughts, emotions or evidence of neurological disorder. The outputs of the brain as a hormone secreting gland are usually less evident. Their discovery required several paradigm shifts in our understanding of anatomy. The first occurred in 1655. Exactly 300 years later, Geoffrey Harris' monograph Neural control of the pituitary gland launched the scientific discipline that is now known as neuroendocrinology. His hypotheses have stood the test of time to a remarkable degree. A key part of his vision concerned the two-way 'interplay between the central nervous system and endocrine glands'. Over the past 60 years, the importance of this reciprocity and the degree to which cerebral functions are influenced by the endocrine environment have become increasingly clear.</p
Hypothalamic Biogenic Amines and the Regulation of Luteinizing Hormone Release in the Rat
No full textAnthropocene and Capitalocene: In Search of a Fusion of Horizons
No full textArtykuł włącza się w dyskusję pomiędzy koncepcjami antropocenu i kapitałocenu. Rozpoczyna go rekonstrukcja zarzutów, jakie pierwszej z nich stawiają m.in. Jason W. Moore, Eileen Crist czy Donna Haraway (niewłaściwa diagnoza przyczyn kryzysu ekologiczno-klimatycznego, ignorowanie nierównej odpowiedzialności za ów kryzys, utrzymywanie antropocentrycznej wizji świata). Następnie autor przedstawia
kontrargumenty zwolenników antropocenu, m.in. Iana Angusa, Clive’a Hamiltona, Dipesha Chakrabarty’ego (antropocen nie ignoruje kontekstu gospodarczo-politycznego, zwolennicy kapitałocenu dokonują nieuprawnionego przeniesienia diagnoz geologicznych na pole socjologii, narracja o kapitalizmie nie jest wystarczająco szeroką ramą badania zmian klimatu). Zakończenie artykułu stanowi próbę fuzji horyzontów obu koncepcji. Autor postrzega je jako dwie wersje hermeneutyki klimatycznej, podejmujące próbę zrozumienia, co dzieje się z naszym światem, i wypracowania odpowiedzi na ów proces.The article joins the discussion between the Anthropocene and the Capitalocene. It begins with a reconstruction of the objections to the first one made by, among others, Jason W. Moore, Eileen Crist or Donna Haraway (incorrect diagnosis of the causes of the ecological and climate crisis, ignoring the unequal responsibility for this crisis, maintaining the anthropocentric vision of the world). Subsequently, the author presents counterarguments of the supporters of the Anthropocene, including Ian Angus, Clive Hamilton, and Dipesh Chakrabarty (the Anthropocene does not ignore the economic and political context, supporters of the Capitalocene make an unjustified transfer of geological diagnoses to the field of sociology, the narrative about capitalism is not a broad enough framework to study climate change). The end of the article attempts to fuse the horizons of both concepts. The author sees them as two versions of climate hermeneutics, attempting to understand what is happening to our world and to work out an answer to this process
The devil in the (demographic) detail
Get PDFCorey J. A. Bradshaw, Clive R. McMahon and Barry W. Broo
Humor chrześcijanina w relacji do wybranych wartości w świetle twórczości Gilberta Keitha Chestertona i Clive’a Staplesa Lewisa
Get PDFBased on the work of Gilbert Keith Chesterton and Clive Staples Lewis, the author analyzes the role of humor in the Christian spirituality and the connection between humor and other values such as love, humility, freedom and truth. One of the conclusions is that both writers regarded and showed humor as an indicator, of the authenticity and depth are lived and realized in the above mentioned values.Na podstawie twórczości Gilberta Keitha Chestertona i Clive’a Staplesa Lewisa autor analizuje rolę humoru w duchowości chrześcijanina i związek humoru z wybranymi wartościami: pokorą, miłością, wolnością i prawdą. Jednym z wniosków jest ten, że obaj tytułowi pisarze uważali i ukazywali humor jako rodzaj indykatora, który wskazuje, z jaką autentycznością i głębią są przeżywane i realizowane wymienione wartości
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