Temat: bioavailability - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Źródła oraz metody badań związków arsenu w próbkach środowiskowych
Sources and methods of determination of arsenic compounds in environmental samples
Autorzy:: Burzyńska, O.
Siebielska, I
Tematy:: soil
bioavailability
incubation
fate; Pokaż więcej
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Powiązania:: https://bibliotekanauki.pl/articles/1819341.pdf Link otwiera się w nowym oknie
Opis:: The article is a review of information available in literature about arsenic and its compounds. The paper characterizes forms of arsenic that can be found in the environment, main chemical and physical transformations it undergoes, application of arsenic in industry and agriculture, dangers associated with arsenic contamination and its toxicity for humans and the environment. Natural and artificial sources of arsenic are discussed. Final part presents fractionating of arsenic in detail, as well as main methods of arsenic determination in the laboratory.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Oral administration is as effective as intraperitoneal administration of amifostine in decreasing nitroxide EPR signal decay in vivo
Autorzy:: Grdina, David J.
Parasca, Adrian
Halpern, Howard J.
Elas, Martyna
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: Toxicokinetics of metals in the earthworm Lumbricus rubellus exposed to natural polluted soils : relevance of laboratory tests to the field situation
Autorzy:: Laskowski, Ryszard
Skip, Borys
Giska, Iwona
van Gestel, Cornelis A. M.
Opis:: The aim of this study was to estimate the bioavailability of essential (Zn, Cu) and non-essential metals (Cd, Pb) to the earthworm Lumbricus rubellus exposed to soils originating from a gradient of metal pollution in Southern Poland. Metal uptake and elimination kinetics were determined and related to soils properties. Experimental results were compared with tissue metal concentrations observed in earthworms from the studied transect. Cd and Pb were intensively accumulated by the earthworms, with very slow or no elimination. Their uptake rate constants, based on 0.01 M CaCl2-extractable concentrations in the soils, increased with soil pH. Internal concentrations of Cu and Zn were maintained by the earthworms at a stable level, suggesting efficient regulation of these metals by the animals. The estimated uptake and elimination kinetics parameters enabled fairly accurate prediction of metal concentrations reached within a life span of L rubellus in nature.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 4.

Tytuł:: A multicarotenoid beadlet for human nutrition - proof of concept of in vitro timed release
Autorzy:: Gellenbeck, Kevin
Salter-Venzon, Dawna
Lala, Rajendra
Chavan, Jayanthi
Tematy:: dissolution
carotenoid
bioavailability
controlled release; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1039766.pdf Link otwiera się w nowym oknie
Opis:: Since the 1980's when the predominate focus of study and use of carotenoids in human nutritional formulations was solely on beta-carotene, there has been a steady increase in research aimed to understand the role of a wide variety of carotenoids in human health. This work has increasingly demonstrated the benefits of a number of carotenoids, and there has been a corresponding increase in the number of carotenoids provided in nutritional supplements (multicarotenoids). Numerous published observations in both human and animal studies suggest significant interaction and competition between various carotenoids during absorption and metabolism, resulting in the inhibition of uptake of one over the other. This competition has the end result of reducing the beneficial effects of the inhibited carotenoid. To limit such competition and maximize carotenoid uptakes, a layered beadlet was designed to release a defined ratio of carotenoids sequentially. Preliminary dissolution testing is presented showing the release profile in simulated digestive conditions of a combination of beta-carotene, alpha carotene, lutein, zeaxanthin, lycopene and astaxanthin derived from natural sources. Comparison is made to an immediate release beadlet formulation using the same combination of carotenoids. These results will be used to guide proof of concept clinical testing for effectiveness in humans.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Strategies in poorly soluble drug delivery systems
Autorzy:: Szaniawska, Magdalena
Tematy:: solubility
drug delivery systems
bioavailability; Pokaż więcej
Wydawca:: Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Powiązania:: https://bibliotekanauki.pl/articles/2079959.pdf Link otwiera się w nowym oknie
Opis:: The form of the active drug administered to patients is important as far as effectiveness of the disease therapy is concerned. From this point of view modifications of medicinal substances are searched for that the obtained compounds have the best physicochemical and pharmacodynamic properties. Pharmaceutical companies allocate significant funds for this type of research. The key property that needs to be improved is the solubility of biologically active substances. This is related to the fact that over 40% of drugs available on the pharmaceutical market are characterized by low solubility in water.Thus, the paper describes the most important strategies used in the poorly soluble drug delivery systems, e.g. physical and chemical modifications, formulation based, modification of partition coefficient and lipid systems. The authors discussed various techniques used to enhance solubility of poorly water soluble drugs with their advantages and limitations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Wpływ biodostępności kadmu w pokarmie na jego rozmieszczenie w organizmie chrząszcza Pterostichus oblongopunctatus.
Effect of cadmium bioavailability in food on its compartmentalization in carabids Pterostichus oblongopunctatus.
Autorzy:: Paciorek, Karolina
Opis:: The aim of this study was to check the possible effect of cadmium bioavailability in food on internal sequestration of this metal in the ground beetle Pterostichus oblongopunctatus (Coleoptera: Carabidae). The beetles were offered either control food or were exposed to Cd via food made of ground mealworm larvae either reared on Cd contaminated medium (Cd-N) or artificially spiked after grinding with CdCl2 solution (Cd-A). Thus, in both cases the same food was used, presumably differing only in the soluble Cd pool available to beetles. Subcellular compartmentalization of cadmium into organelles, heat-sensitive and heat-stable proteins (the first supernatant, S1 fraction), cellular debris (the second supernatant, S2 fraction), metal-rich granules (G fraction) and chitin (fraction C) was checked a few times during contamination (90 days) and decontamination (25 days) phases in toxicokinetic experiment by using different centrifugation steps. Although estimated kinetic parameters, assimilation (kA) and elimination (kE) rate constants were not significant, there were visible differences between treatments (Cd-N vs. Cd-A) in kE for fractions C and G, with higher values of kE found for Cd-N than Cd-A. The kE estimated for fraction S1 were similar in both Cd treatments. The values for kA for a particular fraction did not differ between Cd treatments. Thus, the plausible differences in Cd kinetics between treatments resulted from the differences in kE rather than kA. The amount of Cd sequestered in S1 and G fractions were significantly higher in Cd-A than Cd-N, and the interaction between treatment and day of exposure was significant for fraction G in the uptake phase. No effect of Cd treatment was found in the decontamination phase. Nevertheless the pattern of Cd distribution over different fractions, changed over the decontamination, and the day was significant variable in case of fractions G, S1 i S2. Neither Cd treatment nor day affected the percentage of Cd in any fraction. In general, the percentage of Cd in fraction S1, which is important for the transport of Cd to higher trophic levels in a food web, was ca. 33%.
Badania dotyczyły rozmieszczenia kadmu w organizmie chrząszcza Pterostichus oblongopunctatus (Coleoptera: Carabidae) narażonego na podwyższone stężenia tego metalu w pokarmie. Badane osobniki zostały podzielone na trzy grupy karmione innym typem pokarmu: „naturalnie” skażonym kadmem (Cd-N), sztucznie skażonym kadmem (Cd-S) lub kontrolnym. Stężenie Cd w obu typach skażonego pokarmu było podobne, a różny sposób skażenia powodować miał jedynie różnice w biodostępności metalu dla chrząszczy. Przeprowadzono klasyczny eksperyment toksykokinetyczny, składający się z 90-dniowej fazy kontaminacji oraz 25-dniowej fazy eliminacji. Zawartość kadmu była oznaczana w 4 różnych frakcjach: frakcji C – części schitynizowane , frakcji S1 – frakcja mikrosomalna, zawierająca Cd związany w metalotioneinach, enzymach oraz organellach, frakcji S2 -fragmenty tkanek i błon komórkowych oraz frakcji G – granule. Chociaż parametry krzywych toksykokinetycznych (tempo asymilacji kA i eliminacji kE) nie były oszacowane istotnie statystycznie dla większości badanych frakcji, to jednak dało się zaobserwować, wyższą stałą kE dla frakcji C i G w zabiegu Cd-N niż Cd-S. W przypadku frakcji S1, wartości kE były niemal identyczne dla obu zabiegów. Wartości kA dla poszczególnych frakcji były do siebie zbliżone w obu zabiegach z Cd. Zatem, widoczne różnice w regulacji kadmu w zależności od formy tego metalu w pokarmie są powodowane raczej różnym tempem eliminacji niż różnicami w asymilacji Cd. W fazie kontaminacji istotne różnice w stężeniach Cd pomiędzy zabiegami (Cd-N vs. Cd-S) zaobserwowano dla frakcji G i S1 - stężenia u chrząszczy z zabiegu Cd-S były wyższe niż w zabiegu Cd-N. Ponadto istotna interakcja pomiędzy zabiegiem i dniem intoksykacji wskazała na wpływ dnia na zmiany stężenia Cd we frakcji G. W fazie eliminacji nie wykazano różnic pomiędzy zabiegami w stężeniach Cd dla żadnej frakcji, a wpływ dnia zaznaczył się w przypadku frakcji G, S1 i S2. Zarówno zabieg (Cd-N i Cd-S) jak i dzień eksperymentu nie wpływały istotnie na zmiany w procentowym udziale Cd w badanych frakcjach. Kadm we frakcji S1 stanowił ok. 33% całkowitej ilości metalu w organizmie i można uznać, że taka właśnie pula metalu może oddziaływać toksycznie na chrząszcze i jednocześnie być łatwo dostępna dla organizmów na wyższych poziomach troficznych.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Inne

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Skocz do pozycji: 7.

Autorzy:: Talik, Przemysław
Opis:: The problem of a generic drug substitution has its permanent place in the global discussion of different groups representing both medical and pharmacists, as well as manufacturing circles. This may be evidenced, for example, by the number of publications in the available global scientific databases with a medical profile. There are also discussions in Polish periodicals, where substantive, very interesting and balanced opinions are also expressed by various medical university centers. One of the publications contained the results of the survey showing that 57% of physicians know and understand the term “generic substitution” and 41% do not. This interesting observation encouraged to explain the above concepts in a text addressed to the medical community.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: Effect of apigenin on seizure susceptibility, parvalbumin immunoreactivity, and GABAA receptor expression in the hippocampal neurons in mice
Autorzy:: Socała, Katarzyna
Wlaź, Piotr
Wyska, Elżbieta
Kowalczuk-Vasilev, Edyta
Komar, Małgorzata
Szalak, Radosław
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 9.

Tytuł:: Toxicological assessment of pesticide contaminated soils with use of biotests
Autorzy:: Baczyński, T.
Małachowska-Jutsz, A.
Szalińska, E.
Tematy:: soil toxicity
bioassays
obsolete pesticides
bioavailability; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/955167.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the results of experiments on ecological toxicity assessment performed for 12 soil samples collected at 3 obsolete pesticide “tombs” in Poland, before their final disposal. Bioavailability of the main pollutants: p,p’-DDT, lindane and methoxychlor was assessed for selected samples by consecutive solid phase extraction using a Tenax TA sorbent. Several toxicity bioassays were also carried out, including: reducers (Microtox Soild Phase), producers (Phytotox) and consumers (tests of avoidance, acute toxicity and reproduction with use of the earthworm Eisenia foetida). Data from toxicity tests were discussed against the results of the chemical analysis of a wide range of pesticides determined by GC-ECD and GC-NPD. This part of the study enabled the evaluation of the applicability of the aforementioned bioassays in the assessment of pesticide soil pollution. Results of toxicity tests showed a slight to severe impairment of habitat function for all of the contaminated samples, which was only partially reflected by the analytical data. The most sensitive biotest was earthworm reproduction, followed by Phytotox and earthworm acute toxicity. Earthworm avoidance and Microtox tests were found to be of rather limited usability.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Pharmacokinetic profile of 1-methylnicotinamide nitrate in rats
Autorzy:: Niemczak, Michał
Walczak, Maria
Kuś, Kamil
Chłopicki, Stefan
Zakrzewska, Agnieszka
Pernak, Juliusz
Szafarz, Małgorzata
Opis:: Treatment with 1-methylnicotinamide (MNA), a major metabolite of nicotinamide, exerts antithrombotic, anti-inflammatory, and vasoprotective effects. Yet, pharmacokinetic (PK) profile of MNA has not been fully characterized. In the present work, we analyze the PK profile of the MNA given as a nitrate (MNANO3) in comparison to nitrite (MNANO2) or chloride (MNACl) in rats. The bioavailability of MNA administered as MNANO3 equaled 22.4% as compared to MNANO2 or MNACl (9.2% and 9.1%, respectively). Moreover, in single-pass intestinal perfusion experiments, effective permeability of MNA given as MNANO3 was higher as compared to MNA administered as MNANO2 or MNACl. In turn, tmax was the shortest and Cmax the highest (0.22 h and 56.65μM) for intragastrically administered MNANO2 comparing to MNANO3 (1.92 h, 21.74μM) or MNACl (0.63 h, 16.13μM). Transfer constant between central and peripheral compartments (kcp) and volume of distribution (Vss) for MNANO3 (0.33 h-1 and 1.96 L/kg) were higher as compared to MNANO2 or MNACl (0.11 h-1, 0.08 h-1 for kcp and 1.05 L/kg, 0.76 L/kg for Vss, respectively). In conclusion, we characterized PK profile of MNA and demonstrated that nitrate ion augmented bioavailability and favorably modified PK profile of MNA. Furthermore, given vasoprotective properties of MNA as well as nitrate, MNANO3 represents a bifunctional compound.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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