Wyniki wyszukiwania - Biblioteka Nauki

1

Radiation effects on vitamin A and ßeta-carotene contents in liver products

100%

Taipina M. , del Mastro N.

Nukleonika

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2003

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tom Vol. 48, nr 1

9-11

EN

he movement toward commercialization of the process and the recent actions of various governmental agencies to accept irradiated foods as wholesome, even when high doses are applied has stimulated increased interest in this treatment. Concern for the fate of vitamins when foods are irradiated is almost entirely centered on maintenance of their biological function as essential nutrients. The aim of this work was to assess the effects of ionizing radiation on vitamin A and ßeta-carotene contents in commercialized food products of animal origin, specifically fresh bovine liver and pork pâté de foie. As present Brazilian legislation has no restriction of dose limits to be applied on foods, the 60Co gamma irradiation doses for these experiments were 3 kGy and 30 kGy. The results show a full retention of vitamin content when the applied dose was 3 kGy and a loss of about 60% when the dose was 30 kGy. When applying high doses, it would be necessary to consider this content reduction and proceed to a vitamin supplement when necessary.

2

Kapsułkowanie – metoda stabilizacji witaminy A w technologii wzbogacania żywności

100%

Tataruch K.

Zeszyty Naukowe Uniwersytetu Ekonomicznego w Krakowie

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2013

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nr 906

87-99

EN

The technology of food product fortification through the addition of bioactive ingredients such as vitamins requires the development of innovative methods, due to the high sensitivity of vitamins to the chemical and physical conditions present during the food production process. The adverse effect of temperature, high pressure or oxidising agents may reduce biological activity and can chemically degrade the bioactive components. One challenge in food fortification technology is developing the appropriate formulations of fat-soluble vitamin A. The search for new carriers of vitamin A is extremely important because of its limited stability, insolubility in water and toxicity in excessive amounts. This study characterises the properties and role of vitamin A as a bioactive additive in food fortification technology. It focuses particularly on potential methods for stabilising retinol in order to enhance its functional properties.

3

Letter to the Editor (July 26, 2017) concerning the paper “Impact of electromagnetic radiation emitted by monitors on changes in the cellular membrane structure and protective antioxidant effect of vitamin A – In vitro study”

75%

Mortazavi S. M.

International Journal of Occupational Medicine and Environmental Health

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2017

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tom 31

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nr 3

371-372

4

Authors’ response (September 1, 2017) to the letter to the Editor concerning the paper “Impact of electromagnetic radiation emitted by monitors on changes in the cellular membrane structure and protective antioxidant effect of vitamin A – In vitro study”

75%

Lewicka M. , Henrykowska G. , Zawadzka M. , Rutkowski M. , Pacholski K. , Buczyński A.

International Journal of Occupational Medicine and Environmental Health

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2017

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tom 31

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nr 3

373-375

EN

-

5

Impact of electromagnetic radiation emitted by monitors on changes in the cellular membrane structure and protective antioxidant effect of vitamin A – In vitro study

75%

Lewicka M. , Henrykowska G. , Zawadzka M. , Rutkowski M. , Pacholski K. , Buczyński A.

International Journal of Occupational Medicine and Environmental Health

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2017

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tom 30

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nr 5

695-703

EN

Objectives The increasing number of devices emitting electromagnetic radiation (EMR) in people’s everyday life attracted the attention of researchers because of possible adverse effects of this factor on living organisms. One of the EMR effect may be peroxidation of lipid membranes formed as a result of free radical process. The article presents the results of in vitro studies aimed at identifying changes in malondialdehyde (MDA) concentration – a marker of lipid peroxidation and antioxidant role of vitamin A during the exposure of blood platelets to electromagnetic radiation generated by liquid-crystal-display (LCD) monitors. Material and Methods Electromagnetic radiation emitted by LCD monitors is characterized by parameters: 1 kHz frequency and 220 V/m intensity (15 cm from display screen). The time of exposure was 30 and 60 min. The study was conducted on porcine blood platelets. The samples were divided into 6 groups: unexposed to radiation, unexposed + vitamin A, exposed for 30 min, exposed for 30 min + vitamin A, exposed for 60 min, exposed for 60 min + vitamin A. Results The MDA concentration in blood platelets increases significantly as compared to control values after 60 min of exposure to EMR. A significant decrease in MDA concentration after the addition of vitamin A was noticed. In the blood samples exposed to EMR for 30 and 60 min the MDA concentration was significantly increased by addition of vitamin A. Conclusions The results show the possibly negative effect of electromagnetic radiation on the cellular membrane structure manifested by changes in malondialdehyde concentration and indicate a possible protective role of vitamin A in this process. Int J Occup Med Environ Health 2017;30(5):695–703

6

The role of well-known antioxidant vitamins in the prevention of cadmium-induced toxicity

75%

Sitek A. , Kozłowska L.

International Journal of Occupational Medicine and Environmental Health

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2022

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tom 35

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nr 4

367-392

EN

Long-term exposure to cadmium (Cd) leads to the development of a number of conditions associated with liver and kidney damage, reproductive and cardiovascular disorders, in addition to visual impairment, blindness and hearing loss, among others. Cadmium has been classified as a human carcinogen by the International Agency for Research on Cancer. The toxicity of Cd is related to its pro-oxidant properties and the associated increase in oxidative stress. Antioxidant ingredients may be helpful in preventing the adverse effects of Cd. The effect of well-known antioxidant vitamins (E, C, A and β-carotene) in the prevention of Cd-induced toxicity is presented in this study. Numerous studies in animal models have shown that the effects of vitamins: E, C, A, and β-carotene were effective in reducing Cd concentrations in organs and tissues and reduced Cd-induced changes in liver, kidney, and reproductive, circulatory, nervous, immune, and respiratory systems. In contrast, the limited number of human studies does not allow to accurately determine the role of these nutrients in reducing Cd-induced toxicity, indicating the need for further studies clarifying the role of antioxidant vitamins in reducing Cd-induced toxicity. However, it seems reasonable to promote the consumption of natural food products that are sources of antioxidant vitamins in groups of people with occupational and environmental exposure to Cd.

7

Retinoidy : chemiczna różnorodność dla zdrowia i urody

75%

Pawłowska M. , Marzec M. , Nowak I. , Jankowiak W.

Przemysł Chemiczny

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2023

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tom T. 102, nr 2

196--206

PL

Przedstawiono różnorodną rodzinę witaminy A docenianej od tysiącleci. Dzięki dostępności nowoczesnych technologii oraz wiedzy powiększa się ona w bardzo szybkim tempie. Mnogość struktur chemicznych zapewnia coraz to lepszą biodostępność i stabilność cząsteczek. Dzięki swojej różnorodności retinoidy stosowane są w produktach kosmetycznych i medycznych, zapewniając im szeroki wachlarz właściwości terapeutycznych.

EN

A review, with 43 refs., of vitamin A analogs. Structures, properties, metabolisms as well as cosmetic and medical uses were taken into consideration.

8

Vitamin A deficiency alters the bioelectric parameters and RNA content of rat gastric mucosa in vitro

75%

Ventura U. , Ceriani T. , Montini E. , Romano M. , Ricci V.

Journal of Physiology and Pharmacology

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2003

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tom 54

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nr 4

EN

The present study was aimed to investigate the mechanisms by which vitamin A plays a role in maintaining the efficiency of gastric mucosal barrier. Particularly, we measured electrical parameters and the RNA/DNA ratio of gastric mucosa isolated in vitro from the stomach of rats in which vitamin A-deficiency was induced by means of a vitamin A-free diet and then abolished by means of a massive vitamin A supplementation. Pair-fed vitamin A-nondepleted rats and normal rats fed ad libitum on a standard diet served as controls. Vitamin A status was assayed for each group of rats by measuring the hepatic content of vitamin A. We found that in gastric mucosa vitamin A-deficiency induced: 1) a decrease in both transmucosal potential difference and short-circuit current; 2) an increase in transmucosal electrical resistance; 3) a decrease in RNA content resulting in a decreased RNA/DNA ratio. Abolishment of vitamin A-deficiency restored both electrical parameters and RNA content of rat gastric mucosa. Our results stress the role of vitamin A in maintaining the efficiency of the gastric mucosal barrier. Vitamin A seems to act by stabilizing gastric electrical parameters and by controlling the protein synthesis/turnover in the surface gastric mucosal cells.

9

Studies on the influence of keeping system and season on the serum content of vitamin A and E in cows

75%

Orowicz W. , Zakrzewska H. , Baranow-Baranowski S.

Polish Journal of Veterinary Sciences

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2000

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tom 03

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nr 1

EN

The study was carried out on three groups of cows kept in the systems: I - indoor and pasture, II - indoor with a run, III - indoor. The experiment lasted one year and involved summer and winter feeding. Contents of vitamin A and E in blood serum were determined. The highest serum levels of vitamin E were determined in animals kept in both indoor + pasture and indoor + run systems. The system of keeping did not affect significantly the concentration of vitamin A in the examined period. Statistically significant differences occured in some months but generally in all the systems, its content was at a similar level.

10

Stability of vitamin C and beta-carotene during the tomato paste lyophilization process

63%

Kosmala M. , Ulańska K.

Biotechnology and Food Science

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2022

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tom Vol. 84, nr 1

33--40

EN

The aim of the study was to evaluate the stability of vitamin C and beta-carotene in the freeze-drying process compared to other thermal drying methods. Tomato puree was selected as a model product for testing the stability of vitamin C and vitamin A in drying processes, due to its properties, such as: appropriate consistency, which was favorable for the analyzes performed, and the presence of the above-mentioned vitamins. Model studies were performed on the stability of vitamin C and betacarotene under the conditions of air-drying at 105°C, drying under reduced pressure at 70°C and freeze-drying on a tomato puree matrix. Results proved that freeze-drying is superior to other drying methods with the lowest losses of both vitamin C (losses of 4%) and beta-carotene (losses of 25%) in tomato purée. In the case of drying at 70°C under reduced pressure, the loss of beta-carotene is 55%, and vitamin C - 78%. In the case of air-drying at 105°C, vitamin C is 100% degraded, and the loss of beta-carotene is 91%. Moreover, it can be concluded that vitamin C in a higher dose has a protective effect on carotenoids.

11

Liver content of fatty acids and reproductive indices of carp in relation to level of dietary vitamin A

63%

Maletich M. B. , Rivis J. F.

Acta Scientiarum Polonorum. Zootechnica

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2015

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tom 14

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nr 3

12

Analtyczne problemy ilościowego oznaczania witamin A, E, koenzymu Q10 i kwasu liponowego w próbkach biologicznych

63%

Turkowicz M. J. , Karpińska J.

LAB Laboratoria, Aparatura, Badania

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2011

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tom R. 16, nr 4

24-32

13

Validation of rapid method for simultaneous determination of vitamins A and E in milk using HPLC

63%

Gasior R. , Pieszka M.

Polish Journal of Food and Nutrition Sciences

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2007

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tom 57

|

nr 4[A]

151-155

EN

A method for the simultaneous determination of vitamin A (all-trans-retinol) and vitamin E (α-tocopherol) in milk using the HPLC technique with UV detection (324 nm, vitamin A) and fluorescent detection (Ex295 nm/Em350 nm, vitamin E) was validated. A reverse phase LiChroCART™ 250-4 Superspher™ 100 RP-18 column was used for chromatographic separation. A mixture of methanol and H2O (96.5:3.5 v/v) was used as the eluent (1 mL/min). The analyses were performed after spectrophotometric standardization of standard ethanol solutions, and the results were corrected by recovery. The residual coefficients of variation for the regression equation y=ax were 4.7% (vitamin A) and 8.3% (vitamin E), with r2 > 0.998 (for both vitamins). The limit of quantitation was 0.02 μg/mL and 0.3 μg/mL, repeatability and reproducibility 14% and 12.5%, and uncertainty of the method 20.7% and 18.8% for vitamins A and E, respectively. Vitamin recovery from milk was 51.6-75.1% (vitamin A) and 70.1-87.8% (vitamin E). The results of the reference material analyses (CRM 421, SRM 2383) concur with the certified reference values. The analytical method described is precise, accurate, fast and inexpensive.

PL

Zwalidowano metodę jednoczesnego oznaczania witaminy A (all-trans-retinol) i witaminy E (α-tokoferol) w mleku techniką HPLC z detekcją UV (324 nm, witamina A) i fluoroscencyjną (Ex295 nm/Em350 nm, witamina E). Do rozdziału chromatograficznego użyto kolumny LiChroCART™ 250-4 Superspher™ 100 RP-18. Jako eluent (1 mL/min) zastosowano mieszaninę metanolu z H2O (96,5:3,5 v/v). Alkoholowe roztwory próbek analizowano po uprzednim zmydleniu witamin (KOH, 60%, m/v, 70°C, 60 minut) w środowisku etanolu, wysoleniu, ekstrakcji (octan etylu i heksan, 1:9, v/v) górnej warstwy mieszaniny, odparowaniu pod azotem i rozpuszczeniu pozostałości w etanolu. Wyniki analiz korygowano o wcześniej wyznaczony odzysk (51,6-75,1%, witamina A i 70,1-87,8%, witamina E). Resztowe współczynniki zmienności równania regresji y=ax wynosiły 4,7% (witamina A) i 8,3% (witamina E), a r2 > 0,998 (dla obu witamin), granica oznaczenia ilościowego 0,02 μg/mL i 0,3 μg/mL, powtarzalność i odtwarzalność 14% i 12,5%, a niepewność metody 20,7% i 18,8%, odpowiednio dla witaminy A i E. Wiarygodność metody potwierdzono na materiałach referencyjnych (CRM 421 i SRM 2383). Opisana metoda analityczna, jest precyzyjna, dokładna, szybka i tania.

14

Influence of dimethylnitrosamine on fatty acids composition of retinol esters in rat liver cells

63%

Cyganek I. , Tabor J. , Nowak W. , Gawedzka A. , Drag J. , Jaskiewicz J.

Acta Toxicologica

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2007

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tom 15

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nr 2

133-140

15

The distribution of vitamins A, E and C in tissues of laying hens during reproductive period

63%

Kuklenko T. , Ionov I. , Surai P.

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1997

|

tom 31

16

Dietary carotenoids in normal and pathological tissues of corpus uteri

63%

Czeczuga-Semeniuk E. , Wolczynski S.

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tom 46

|

nr 3

283-290

17

Witamina A – funkcje i znaczenie dla człowieka

63%

Zaborska A. , Król J. , Brodziak A.

Przemysł Spożywczy

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2015

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tom T. 69, nr 7

36--38

PL

Witamina A pełni bardzo ważne funkcje i ma ogromne znaczenie w wielu procesach fizjologicznych przebiegających w organizmie człowieka. Przede wszystkim jest znana z udziału w procesie prawidłowego widzenia (jej podstawowa forma – retinol). Witamina A ma duży wpływ na wzrost i różnicowanie się komórek organizmu, utrzymuje w dobrej kondycji skórę, włosy i paznokcie, likwiduje przebarwienia wywołane promieniami słonecznymi, stymuluje wytwarzanie kolagenu i elastyny w warstwie właściwej skóry, reguluje pracę gruczołów łojowych, przyspiesza proces gojenia naskórka oraz leczy schorzenia skórne – trądzik i łuszczycę. Produkty pochodzenia zwierzęcego są wyłącznym źródłem witaminy A przy czym najwięcej tej witaminy zawierają tłuste ryby, wątroba, mleko i produkty mleczne oraz jaja. Karotenoidy będące prekursorami witaminy A występują w warzywach i owocach. W Polsce nie ma większego zagrożenia wystąpienia niedoborów witaminy A w diecie, ale spożywanie coraz większej ilości produktów z obniżoną zawartością tłuszczów lub beztłuszczowych może do tego doprowadzić.

EN

Vitamin A plays an important role in many physiological processes occurring in the human body. First of all, it is known for the participation in the process of correct vision (its basic form – retinol). Vitamin A participates in the growth and differentiation of the cells in the body, maintains the skin, hair and nails in a good condition, eliminates discoloration caused by sunlight, stimulates the production of collagen and elastin in the dermal layer, regulates the function of sebaceous glands, fastens the healing process of epidermis, and cures the skin disorders (acne and psoriasis). Animal products are the sole source of vitamin A, and especially oily fish, liver, milk, dairy products and eggs. Carotenoids, being precursors of vitamin A, are present in vegetables and fruits. In Poland there is no greater danger of vitamin A deficiency in the diet, but the consumption of greater and greater quantities of low-fat or fat-free products by the modern consumer may lead to such phenomenon.

18

Retinoids as an immunity-modulator in dermatology disorders

63%

Chen W. , Zhao S. , Zhu W. , Wu L. , Chen X.

Archivum Immunologiae et Therapiae Experimentalis

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2019

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tom 67

|

nr 6

19

Stability of vitamins A and E in mixed feed as affected by extrusion temperature and the moisture content of mixture

63%

Adamski K. , Kruczynska H.

Polish Journal of Natural Sciences. Supplement

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2006

|

tom 03

39-43

20

Plasma concentrations of vitamin E, vitamin A and beta-carotene in healthy men

63%

Grzelinska Z. , Gromadzinska J. , Swiercz R. , Wasowicz W.

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tom 16

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nr 2

EN

The aim of the study was to adapt the method for the determination of vitamins E, A, and β-carotene and to assay them quantitatively in plasma of municipal transport drivers. The study embraced 147 municipal transport male drivers, aged 23–58 years. The Waters 2695 integrated analytical system of high-pressure liquid chromatography (HPLC), equipped with a UV-VIS detector was used to determine the studied compounds. Our analysis of the quantitative data by age and seniority did not show significant differences in the concentrations of the analyzed compounds between the study groups, except for the concentration of β-carotene, which was significantly lower in drivers aged over 46 years with the longest employment (over 16 years) compared to the younger groups.