Wyniki wyszukiwania - Biblioteka Nauki

1

Colour-Constitution Relationships of Free radicals of 2-Methyl-1,4,6-triphenylpyridines

100%

Soroka J. , Perez-Medina F. , Soroka K.

Polish Journal of Chemistry

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2000

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tom Vol. 74, nr 5

687-700

EN

Special type of equation, being essential Taft's approach, was constructed and tested. It, so-called extended two-parameter Taft equation, allows correlation analysis of polysubstituted compounds. By this equation a correlation analysis of the electronic transition energy of thirty-two free radicals was carried out.

2

How much coenzyme Q10 and vitamin C is needed to scavenge all free radicals formed during the 10 000 m run ?

100%

Popinigis J. , Lenaz G. , Chalcarz W.

Polish Journal of Environmental Studies

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1997

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tom 06

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nr 2

3

Oxidant defence enzymes in different isolates of Trichinella

100%

Hadas E. , Rodriguez-Caabeiro F. , Gonzales A. J.

Acta Parasitologica

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1994

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tom 39

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nr 1

EN

The prevention of biological damage brought about by free radical mediated mechanisms can be achieved by specific chemical scavengers which trap free radicals as well as by protective enzymes that remove hydrogen peroxide or superoxide radicals. The aim of this study was to carry out a comparative analysis of enzymes acting against free-radicals and peroxides in Trichinella spiralis, T. nelsoni and T. pseudospiralis isolates. The activity of superoxide dismutase in T. pseudospiralis was about two times higher than in T. spiralis and about 1.5 times higher than that of T. nelsoni. In all the isolates only one band representing superoxide dismutase was identified on electrophoretic analysis. Catalase and peroxidase activities were very low. Using electrophoretical analysis we found three identical bands of peroxidase activity in the species investigated. Our data suggest that, with regard to the anti-oxidant enzymes, superoxide dismutase plays an important role whereas peroxidase and catalase play lesser roles in the defence of Trichinella spp. larvae against host generated free radicals released during the response to infection.

4

An approach to free radicals in sport and exercise

100%

Bargossi A. M. , Grossi G. , Blanchi G. P. , Fiorella P. L.

Polish Journal of Environmental Studies

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1997

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tom 06

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nr 2

5

Strategies of biochemical defence mechanisms of parasites against oxidants and free radicals

100%

Hadas E. , Stankiewicz M.

Acta Parasitologica

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1996

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tom 41

|

nr 1

EN

Biological damage brought about by free radical mediated mechanisms can be prevented either by specific chemical scavengers or by protective enzymes that neutralise the radicals or their precursors. Protection can also occur by repair of damage once it has occurred. This review summarises studies of the major biochemical defence mechanisms against oxidants and free radicals and the mechanisms that repair oxidatively damaged proteins. These mechanisms may be a field in the search for improved ways to inhibit parasite survival.

6

Antiradical activity of ciders

88%

Foltyniewicz M. , Kiewlicz J. , Zielinski R.

Towaroznawcze Problemy Jakości. Polskie Towarzystwo Towaroznawcze

|

2017

|

nr 3

7

Synthesis Based on 9-Amino-N-picrylcarbazyl

88%

Ionita G. , Caproiu M. , Meghea A. , Maior O. , Rovinaru M. , Ionita P.

Polish Journal of Chemistry

|

1999

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tom vol. 73 nr 7

1177-1183

EN

Starting from 9-amino-N-picrylcarbazole, the nitro-, cyano-, bromo- and dibromo-derivatives of the title compound, and the corresponding free radicals, were synthesized. The pK values and the redox properties of the compounds synthesized were reported.

8

Antioxidant activity: what do we measure?

88%

Bartosz G. , Bartosz M.

Acta Biochimica Polonica

|

1999

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tom 46

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nr 1

EN

Inhibition of oxidation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) by free radicals generated by decomposition of 2,2'-azobis(2-amidopropane) (ABAP) by antioxidants and biological material was studied. A correlation was found between the ability of various substances to delay the onset of ABTS oxidation and their rapid reduction of the ABTS+* cation radical, and between the ability to reduce the maximal rate of ABTS oxidation and slow reduction of ABTS+*. The length of the lag period of ABTS oxidation was found to be independent of ABTS concentration. Similar decrease of peroxynitrite-induced ABTS+* formation by antioxidants was observed when the antioxidants were added before and after peroxynitrite. All these findings indicate that the main effect of antioxidants in this system is reduction of ABTS+* and not prevention of its formation. Reduction of oxidation products rather than inhibition of their formation may be the predominant mode of action of antioxidants in various assays of antioxidant activity.

9

The influence of melanin on the process of lipid peroxidation. Part 5: The interaction of melamin with lipid and oxygen free radicals

88%

Ezzahir A.

Applied Biology Communications. Lublin Scientific Center

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1992

|

tom 02

|

nr 4

10

Electron paramagnetic resonance [EPR] investigations of laser induced free radicals in spring wheat grains

88%

Drozd D. , Szajner H. , Jezierski A.

International Agrophysics

|

1999

|

tom 13

|

nr 3

11

The antioxidant activity of new ammonium salts

88%

Gabrielska J. , Przestalski S. , Witek S.

Biophysics of Membrane Transport

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1994

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tom 12

|

nr 2

12

The alcohol dependence and plasma selenium concentration

88%

Kucharska-Mazur J. , Samochowiec J. , Zawierta J. , Chlubek D.

Acta Poloniae Toxicologica

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2000

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tom 08

|

nr 2

13

The mechanism of preconditioning involves mitoKATP mediated prevention of free radical generation and apoptosis in the post-ischemic heart

88%

Czarnowska E. , Duda M. , Beresewicz A.

Cellular and Molecular Biology Letters

|

2002

|

tom 07

|

nr Suppl.

14

Antiradical activity of herbal mixtures with sedative properties

75%

Hawrylianka Z. , Szymusiak H. , Zielinski R.

Towaroznawcze Problemy Jakości. Polskie Towarzystwo Towaroznawcze

|

2014

|

nr 1

15

Influence of 5-aminoisoquinolin-1-one (5-AIQ) on neutrophil chemiluminescence in rats with transient and prolonged focal cerebral ischaemia and after reperfusion

75%

Hendryk S. , Czuba Z. P. , Jedrzejowska-Szypulka H. , Szliszka E. , Phillips V. A. , Threadgill M. D. , Krol W.

Journal of Physiology and Pharmacology

|

2008

|

tom 59

|

nr 4

811-822

EN

Stimulation of neutrophils by different factors increases their oxidative activity and the free radicals produced can report on the degree of activation. Poly(adenosine 5’-diphosphate ribose)polymerase-1 (PARP-1), a nuclear enzyme activated by strand breaks in DNA, plays an important role in the tissue injury associated with ischaemia-reperfusion injury and inflammation. 5-Aminoisoquinolin-1-one (5-AIQ) is a potent inhibitor of PARP-1 activity in vitro and in vivo in rats. Acute (80 min) and prolonged (24h) focal cerebral ischaemia was induced in rats by obstruction of the median cerebral artery, with or without reperfusion, with or without administration of 5-AIQ. The oxidative activity of neutrophils was measured by chemiluminescence. Administration of 5-AIQ.HCl (3.0 mg kg-1 b.w. - i.v.) caused a significant decrease in the oxidative activity of neutrophils in the group which had experienced chronic ischaemia for 24h but had no significant effect in the group which had received 80 min ischaemia, when compared to the control group. Increase of the oxidative activity of neutrophils was confirmed in rats with prolonged cerebral ischaemia, followed by reperfusion. 5-AIQ probably may decrease this activity through inhibition of PARP-1 in focus of local ischaemia as well as hence lowering the expression of inflammatory mediators by activated neutrophils.

16

Abortifacient and antioxidant activities of Avicennia marina

75%

Srikanth M. , Ganga Rao B. , Mallikarjuna Rao T. , Rajananda Swamy T.

International Letters of Natural Sciences

|

2015

|

tom 06

EN

The current study was intended to evaluate abortifacient and antioxidant activity of Avicennia marina leaves extracts. Abortifacient activity was evaluated in rats, compared with standard drug (Mifepristone) and antioxidant activity was evaluated by using three free radicals (Superoxide, Hydroxyl and DPPH) compared with Ascorbic acid. The extracts were showed pre implantation loss, post implantation loss of implantations and decreased the survival ration of foetuses. Among all extracts hydroalcoholic extract showed better activity. The selected plant extracts showed concentration dependent percentage inhibition of free radicals. Among three extracts hydroalcoholic extract showed better activity with IC50 values on superoxide, hydroxyl and DPPH radicals were 203μg, 237μg and 143μg. From the results obtained during the study it the hydroalcoholic extract was used for the isolation of pure compounds, and isolated the different compounds (β-sitosterol, Lupeol and Betulinic acid).

17

Role of the antioxidants in the protection against oxidative stress in cattle - nonenzymatic mechanisms (Part 2)

75%

Kleczkowski M. , Klucinski W. , Sikora J. , Zdanowicz M. , Dziekan P.

Polish Journal of Veterinary Sciences

|

2003

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tom 06

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nr 4

18

Perception of dental practitioners regarding the use of antioxidants in oral health

75%

Randhawa R. K. , Gupta N. , Bansal M. , Arora V. , Gupta P. , Thakar S.

Roczniki Państwowego Zakładu Higieny

|

2016

|

tom 67

|

nr 3

EN

Background. Free radicals play a key role in the development of several pathological conditions. Therefore, antioxidants (AOs) are the first line of defense against free radical damage and are critical for maintaining optimum health and wellbeing. Objectives: To assess the perception of dental practitioners regarding use of antioxidants in oral health. Method. A cross-sectional questionnaire study was conducted among 296 dental practitioners in Tricity (Chandigarh, Mohali, Panchkula, India). A self-structured close-ended questionnaire was used to assess the perception of dentists regarding the use of antioxidants in their patients. It consisted of 12 questions with dichotomous response and five point likert scale ranging from strongly agree to strongly disagree. Descriptive statistics were used to summarize the data, followed by the Chi-square test to check significant differences between the responses. Correlation between responses were analysed through the Spearman’s rank correlation. Statistical analysis was done using Statistical Package for Social Sciences version 20 (Illinois, Chicago, USA). Results. A statistically significant difference was observed between genders, with females 181 (61%) having more knowledge than males 115 (39%) regarding the use of antioxidants in their clinical practice. It has been found that dental professionals in academics prescribes more antioxidants to their patients than the private practitioners. Postgraduates 76 (77.6%) had a higher level of knowledge than graduates 86 (43%). Conclusions. Knowledge about antioxidants should be highlighted in the health sciences curriculum. It is recommended to expand the use of antioxidants in oral health to bring down the burden of chronic diseases like periodontitis and catastrophic diseases like precancerous lesions and oral cancer.

19

Influence of zearalenone on free radical reactions in rat liver cells

75%

Stadnik A. , Wojtowicz-Chomicz K. , Borzecki A.

Bulletin of the Veterinary Institute in Puławy

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2010

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tom 54

|

nr 4

EN

The aim of the study was to examine the toxic effect of different doses of zearalenone on liver cells by estimating mycotoxin influence on antioxidant systems and on formation of free radicals in the liver. The research was carried out on male Wistar rats. The rats were divided into nine groups of 10 animals each. Group A was orally given 8% ethyl alcohol once a day for 10 d. Groups B, C, D, and E were given, orally once a day 50, 100, 200, and 500 µg/kg b.w. of zearalenone in alcohol solution for 10 days. The animals from groups X, Y. and Z received a single dose of 1, 2, and 3 mg/kg b.w of zearalenone, respectively, and group W (control) - a single dose of 8% ethyl alcohol. The liver was removed and homogenised. Glutathione peroxidase and superoxide dismutase activities, and concentration of L-ascorbic acid in the homogenate were determined. Received outcome and statistical analysis showed the essential fall of superoxide dismutase activity after 10 d of administering 200 and 500 µg/kg b.w of ZEA in comparison with the control group, and drop of glutathione peroxidase activity after 500 µg/kg b.w. dose. The results of the experiment showed that oxidative stress is one of the main toxic effects of zearalenone activity. Low doses of zearalenone applied for a long time do not have an influence on free radical reaction. Short-lasting zearalenone influence does not cause changes in the activity of antioxidant enzymes.

20

Tentative Identification of C3No Radical Luminescence in Solid Krypton

75%

Crépin C. , Monéron L. , Douin S. , Boyé-Péronne S. , Kołos R. , Turowski M. , Gronowski M. , Sepioł J. , Bénilan Y. , Gazeau M. C.

Polish Journal of Chemistry

|

2008

|

tom Vol. 82, nr 4

741-749

EN

A product of cyanoacetylene photodissociation in Kr matrices gives rise to visible emission bands tentatively identified as due to the fluorescence and to the phosphorescence of the C3No radical. This assignment, which involves the low lying ~A 2P state as the final one for both emissions, is based on the isotopic substitution study and on former theoretical predictions.