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Wyświetlanie 1-4 z 4
Tytuł:
Thyroid hormones in the cerebrospinal fluid of the third ventricle of adult female sheep during different periods of reproductive activity
Autorzy:
Skipor, J.
Misztal, T.
Szczepkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/30646.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thyroid hormone
cerebrospinal fluid
ventricle
adult
female
sheep
reproductive activity
reproductive period
ewe
thyroxine
triiodothyronine
breeding season
anoestrus
Opis:
Thyroid hormones (THs) are obligatory for transition from breeding season to anestrus in sheep. In this process, THs act during a very limited time of the year and primarily within the brain. In ewes chronically equipped for sampling cerebrospinal fluid (CSF) from the third ventricle, we have characterized the concentrations of total and free thyroxine (T4), triiodothyronine (T3), and total reverse T3 (rT3) in the CSF during breeding season, anestrus and during a critical period required for transition to anestrus (December-March). The total T4, T3, rT3 and free T3 average concentrations (± SEM) in CSF were 1.5 ± 0.07 ng/ml, 14.5 ± 1.2 pg/ml, 43 ± 7.4 pg/ml, and 0.6 ± 0.05 pg/ml, respectively, and all were significantly lower (p < 0.001) than in blood plasma except free T4 (12.6 ± 1.1 pg/ml), which was similar to that in plasma. There was a seasonal trend (p < 0.05) in the concentration of total T3 (highest in December) and free T4 (highest in November) in the CSF that does not follow that in blood plasma. During the period of transition to anestrus the CSF total T3/TT4 molar ratio and free T3/ T4 ratio were significantly lower (p < 0.05 and p < 0.01, respectively) than in blood plasma, while the total rT3/T4 ratio was significantly higher (p < 0.01) at the end of this period (March). Additionally, the CSF total rT3 concentrations were also significantly correlated with the CSF total T4 levels (r = 0.57; p < 0.05). In conclusion, the CSF in sheep may serve as a considerable source of thyroid hormones for neuroendocrine events. The lack of significant changes in THs concentrations in the CSF during the period of transition to anestrus indicate that neither seasonal changes of THs circulating in the blood plasma nor THs circulating in the CSF actively drive the transition to anestrus.
Źródło:
Polish Journal of Veterinary Sciences; 2010, 13, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of a two-week treatment with low dose of ortho-substituted polychlorinated biphenyls (PCB104 and PCB153) on VEGF-receptor system expression in the choroid plexus in adult ewes
Autorzy:
Szczepkowska, A.
Mlynarczuk, J.
Grochowalski, A.
Dufourny, L.
Thiery, J.-C.
Skipor, J.
Powiązania:
https://bibliotekanauki.pl/articles/31749.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Ortho-substituted polychlorinated biphenyl (PCB) congeners, which constitute a large part of PCB residues found in the environment and in animal tissues, are known to exert potent vascular effects and can activate endothelial cells in the periphery and in the brain. The choroid plexus (CP) is responsible for cerebrospinal fluid (CSF) production and its epithelial cell layer is responsible for structure and functions of the blood-CSF barrier. The aims of this study were: 1) to investigate if environmentally relevant doses of PCB153 and similar doses of PCB104 caused changes in the expression of vascular endothelial growth factor (VEGF) - receptor system, which maintains CP function, and 2) to determine the level of both congeners in blood plasma after their oral administration. Studies of both congeners were performed on ovariectomized ewes treated per os with low doses (0.1 mg/kg, three times a week for two weeks) of PCB153 (n=4) or PCB104 (n=4) and vehicle (control, n=4). The effects of PCB153 and PCB104 treatment on mRNA expression of two isoforms of VEGF (VEGF120 and VEGF164) and their receptors Flt-1 and KDR were determined using real-time PCR. Plasma concentration of PCBs was measured using high resolution chromatography/tandem mass spectrometry (HRGC/MS-MS). We observed that neither PCB153 nor PCB104 significantly altered the mRNA of the VEGF-receptor system in the CP. In PCB treated animals plasma concentration of PCB153 (1.425 ± 0.16 ng/g of dry mass, DM) was about 150 times higher than PCB104 (0.009 ± 0.007ng/g DM). In control animals the PCB153 level was 0.14 ± 0.031 ng/g DM, while the PCB104 level was below detection level. This indicates that increase in plasma PCB153 concentration to levels similar to those reported in humans and of PCB104 concentration to levels 100 times higher than those found in human plasma did not affect the VEGF-receptor system in the CP in adult ewes. The significantly lower increase of PCB104 than PCB153 concentration in blood after oral administration suggests different absorption of both congeners from the digestive tract.
Źródło:
Polish Journal of Veterinary Sciences; 2012, 15, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zrzeszanie się producentów rolnych jako przykład współdziałania w sektorze rolnictwa - doświadczenia wybranych krajów członkowskich Unii Europejskiej
Association of agricultural producers as an example of cooperation in the agricultural sector - the experience of selected EU countries
Autorzy:
Zielinska-Szczepkowska, J.
Kisiel, R.
Powiązania:
https://bibliotekanauki.pl/articles/573955.pdf
Data publikacji:
2016
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Źródło:
Zeszyty Naukowe Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie. Problemy Rolnictwa Światowego; 2016, 16[31], 2
2081-6960
Pojawia się w:
Zeszyty Naukowe Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie. Problemy Rolnictwa Światowego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural and cultural resources of Green Kurpie as drivers of tourism development
Autorzy:
Kisiel, R.
Zielińska-Szczepkowska, J.
Taradejna, D.
Powiązania:
https://bibliotekanauki.pl/articles/96553.pdf
Data publikacji:
2018
Wydawca:
Fundacja Ekonomistów Środowiska i Zasobów Naturalnych
Tematy:
natural area
cultural resource
tourism attractiveness
obszar naturalny
zasoby kulturowe
atrakcyjność turystyczna
Opis:
The purpose of this paper is to present the natural and cultural resources of the region of Green Kurpie (identified with the Green Wilderness of Kurpie) as drivers of tourism development. The region under analysis, located across two voivodeships: Mazowieckie and Podlaskie, has special natural resources: woods and nature reserves which preserve the natural beauty of the Kurpie Forest, as well as its own culture manifested in original buildings, ornamentation, folk handicrafts, clothing and local dialect. It is a theoretical and empirical article. The author applied the following research methods: deductive studies of literature on the subject and questionnaire studies with the use of a standardised questionnaire survey carried out among 400 respondents from 12 voivodeships in Poland (N=400). In the eyes of the respondents, vast forests, natural reserves, a wealth of rivers and meadows, as well as a distinctive culture: local dialect, unique architecture, crafts and folk costumes are conducive to the development of nature and culture tourism in the region. Although most respondents believe that the region is attractive for tourists, they also see the necessity to take additional measures to active policy on wider tourism promotion.
Źródło:
Ekonomia i Środowisko; 2018, 2; 231-245
0867-8898
Pojawia się w:
Ekonomia i Środowisko
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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