213 research outputs found
Pesticide Use and Degradation Strategies: Food Safety, Challenges and Perspectives
While recognizing the gaps in pesticide regulations that impact consumer safety, public health concerns associated with pesticide contamination of foods are pointed out. The strategies and research directions proposed to prevent and/or reduce pesticide adverse effects on human health and the environment are discussed. Special attention is paid to organophosphate pesticides, as widely applied insecticides in agriculture, veterinary practices, and urban areas. Biotic and abiotic strategies for organophosphate pesticide degradation are discussed from a food safety perspective, indicating associated challenges and potential for further improvements. As food systems are endangered globally by unprecedented challenges, there is an urgent need to globally harmonize pesticide regulations and improve methodologies in the area of food safety to protect human health
Flux of Ca2+ ions in the synaptosomal mitochondrial membrane
In the present study, the flux of Ca2+ ions in the synaptosomal mitochondrial membrane isolated from the whole brain and hippocampus of chronically ovariectomized female rats was examined. Under basal conditions no significant difference was found. Addition of estradiol (0.5 nmol/l) in the preincubation mixture decreased significantly (25%) Na-dependent Ca2+ efflux in mitochondria from both sources which may be the way that it exerts its role in nerve cell homeostasis.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
Effects of metal ions on ecto-ATPase activity in plasma membrane isolated from the rat ovary
Effects of increasing concentrations of metal salts SrCl2, CsCl, CrCl3, CdCl2, and HgCl2 on rat ovarian plasma membrane ecto-ATPase activity were investigated. CrCl3, CdCl2, and HgCl2 exert total inhibition of enzyme activity in the presence of 0.01 M and 0.1 M respectively. SrCl2 and CsCl exhibit up to 25% of inhibition. According to the IC50, ecto-ATPase possesses greater sensibility to Cd2+ (IC50 is 0.887 mM) > Cr3+ (IC50 is 1.936 mM) > Hg2+ (IC50 is 4.39 mM). All investigated ions exert negative cooperativity (n<1). Physico-chemical properties of the metal are of importance in metal toxicity. Cr3+ and Cd2+ ions, with lower radius may inhibit ecto-ATPase activity by binding to hydrolytic site or by replacing Mg2+ in Mg-ATP, a substrate of the enzyme. Hg2+, as a larger ion probably inhibits the enzyme activity through conformational changing the enzyme by binding to S-S or -SH groups on the site distinct to hydrolytic one. By inhibiting the enzyme activity these metals may affect maturation and release of oocytes as well as synthesis and release of gonadal hormones and decrease the fertility of mammalsPhysical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
Positive correlation between micronuclei and necrosis of lymphocytes in medical personnel occupationally exposed to ionizing radiation
BACKGROUND: Current radiation protection standards are based on premise that any radiation dose may result in detrimental health effects. The aim of this study was to evaluate extent of the DNA damages (measured by induction of micronuclei) and interphase cell death in circulating lymphocytes of medical personnel exposed to ionizing radiation. METHODS: Baseline micronuclei were assessed using the cytokinesis-block micronucleus test. Cytotoxicity was analyzed by flow cytometry for human white blood cells to identify cells that displayed apoptosis-associated DNA condensation. Necrotic cells were analyzed simultaneously. All parameters were compared with corresponding controls. RESULTS: A statistically significant difference (t = 4.54, p = 0.002) was found between exposed and control group in the yield of baseline micronuclei. The level of baseline micronuclei correlated positively with necrosis of leucocytes (r=0.09, p=0.68 in exposed group, r=0.02, p=0.97 in controls). An inverse correlation between baseline micronuclei and apoptosis was noted in both groups of examinees (r = -0.26, p = 0.27 in exposed group, r = -0.09, p=0.80 in controls). The data obtained also suggested an inverse correlation between necrosis and apoptosis (r = -0.37, p = 0.11 in exposed group, r = -0.89, p = 0.001 in controls). CONCLUSION: Flow cytometry being a rapid, fast, and accurate method is strongly recommended in evaluation of radiation injuries. The integration of apoptosis and necrosis into micronucleus assay could be very important in the assessment of cumulative effects of ionizing radiation in occupationally exposed medical personnel
Voltammetric methods based on carbon electrodes modified with multi walled carbon nanotubes and bismuth and antimony particles based composites for determination of selected target analytes
Cilj ove doktorske disertacija bio je razvoj novih, osetljivih, selektivnih i ekonomski isplativih voltametrijskih radnih elektroda za praćenje odabranih analita kako u laboratorijskim tako i pri terenskim uslovima. Ispitivana je mogućnost primene ovih radnih elektroda primenom voltametrijskih metoda kako u model rastvorima tako i u pojedinim realnim sistemima. SW-ASV zasnovana na elektrodama od staklastog ugljenika površinski modifikovanim Bi-MWCNT i BiOCl-MWCNT je primenjena za određivanje jona Pb(II) i Cd(II) pri optimizovanim uslovima merenja. Određivanje ciljnih jona vršeno je pri radnom potencijalu od -1,2 V (izmeren u odnosu na zasićenu kalomelovu elektrodu) i vremenu elektrodepozicije jona od 120 s. Sva merenja su izvršena u rastvoru acetatnog pufera čija je pH-vrednost iznosila 4,0. Primenjeni koncentracioni opseg ciljnih analita iznosio je od 5 do 50 μg dm -3 . Primenom ovog tipa elektrode dobijene su vrednosti granice detekcije za jone Pb(II) i Cd(II) 0,57 μg dm -3 i 1,2 μg dm-3 , redom. Dobijena RSD iznosila je manje od 10% za oba jona. Ova metoda je primenjena i za određivanje ciljnih jona u realnom uzorku porne vode sedimenta a rezultati dobijeni optimizovanom voltametrijskom metodom su u dobroj saglasnosti sa rezultatima koji su dobijeni primenom komparativne GFAAS metode. Bizmut oksihlorid-višezidne ugljenične nanocevi kompozitni materijal je primenjen za površinsko modifikovanje elektrode od staklastog ugljenika za brzo i jednostavno voltametrijsko određivanje tragova Zn(II)-jona primenom SW-ASV metode. BiOClMWCNT/GCE je pokazala linearan analitički odgovor u osegu koncentracija od 2,50 do 80,0 μg dm -3 sa dobijenom vrednošću GD 0,75 μg dm-3 pri akumulacionom vremenu od 120 s i potencijalu elektrodepozicije -1,40 V u odnosu na ZKE. Merenja su vršena u acetatnom puferu pH 4,5. Dobijena RSD iznosila je 4,8 %. Upoređene su performanse novodizajnirane BiOCl-MWCNT/GCE elektrode i tradicionalne elektrode na bazi bizmut filma (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE i nemodifikovane GC elektrode. Novodizajnirana elektroda je primenjena za detekciju i određivanje Zn(II)-jona u realnim uzorcima kao što su dijetetski suplement i pekarski kvasac. Dobijeni rezultati su uporedivi sa deklarisanom vrednošću u slučaju dijetetskog suplementa a u slučaju pekarskog kvasca sa rezultatima dobijenih komparativnom FAAS . Elektroda od ugljenične paste je površinski modifikovana pripremljenim kompozitom koji je izgrađen od višezidnih ugljeničnih nanocevi i čestica Sb2O3. Kompozitni materijal je okarakterisan primenom TEM, EDS i XRD mernih tehnika. Sb2O3-MWCNT/CPE je okarakterisana primenom ciklične voltametrije a merenja su vršena u rastvoru hlorovodonične kiseline (pH 2,0). Primenom SW-ASV metode ova radna elektroda je upotrebljena za određivanje jona Pb(II) i Cd(II) u koncentracionom opsegu 2,0-40,0 μg dm -3 za Pb(II)-jon i 2,0-40,0 μg dm -3 za Cd(II)-jon pri čemu su dobijene dobre linearne zavisnosti za oba ciljna jona. Optimalna procedura uključuje primenu Sb2O3-MWCNT/CPE u 0,01 mol dm -3 hlorovodoničnoj kiselini uz vreme elektrodepozicije jona iz rastvora od 120 s na potencijaluod -1,2 V, pri čemu su dobijene vrednosti za GD 1,1 μg dm -3 Cd(II) i 1,6 μg dm -3 Pb(II). Optimizovana metoda zasnovana na ovom tipu voltametrijskog senzora je uspešno primenjena za određivanje jona Cd(II) u obogaćenom uzorku česmenske vode, gde su se dobijene vrednosti u saglasnosti sa očekivanom. Elektroda od ugljenične paste površinski je modifikovana primenom Sb2O3-MWCNT nanokompozitnog materijala i primenjena za direktno voltametrijsko određivanje imidakloprida u model rastvorima. U cilju postizanja što boljih analitičkih performansi optimizovani su eksperimentalni uslovi merenja kao što su pH-vrednost rastvora pomoćnog elektrolita i kondicioniranje površine voltametrijskog senzora. Kao optimalna pH-vrednost pomoćnog elektolita (Britton-Robinsonovog pufera) odabrana je pH 7,0, a ponavljanje ciklusa cikliranja najmanje 4 puta povoljno utiče na stabilnost voltametrijskih signala. Optimizovana metoda primenjena je za SW direktno katodno određivanje imidakloprida u koncentracionom intervalu od 1,41 do 32,77 μg cm -3 uz dobijeni korelacioni faktor od 0,9995. Na osnovu dobijenih rezultata može se zaključiti da su razvijene analitičke metode pre svega osetljive, selektivne, reproduktivne i jednostavne što omogućava njihovu primenu za veliki broj uzoraka. Merenjima u model i realnim rastvorima dokazana je mogućnost njihove primene u komplikovanim matriksima, pri različitim pH vredostima pri čemu su dobijeni rezultati koji su u saglasnosti sa rezultatima primenjenih komparativnih metoda. Naravno, za dobijanje reprezentativnih rezultata neohodno je izvršiti optimizaciju uslova merenja što podrazumeva sam odabir supstrat-elektrode, odabir površinskog modifikatora i optimizaciju eksperimentalnih uslova merenja.The aim of this Ph.D. thesis was the development of new, sensitive, selective and economically viable voltametric working electrode for continuous monitoring of different target analytes. The use of these advantaged working electrodes was investigated using voltametric methods both in model solutions and in certain real systems.SW-ASV based on glassy carbon electrode surface modified with Bi- MWCNT and BiOCl-MWCNT were applied for determination of Pb(II) and Cd(II) ions. Voltametric determination of Pb(II) and Cd(II) ions was performed at working potential of -1.2 V (measured against the saturated calomel electrode) and time of electrodeposition of 120 s. All measurements were performed in acetate buffer solution pH 4.0. Concentration range of targetanalites were 5-50 μg dm -3 . Using this type of electrode, obtained detection limits for Pb(II) and Cd(II) ions were 0.57 μg dm -3 and 1.2 μg dm -3 , respectively, with RSD lower than 10%.This method was applied for target ions determination in sediment pore water sample, and obtained results are comparable with those who are obtained using GFAAS method. Bismuth oxychloride-multiwalled carbon nanotubes composite material was applied for surface modification of the glass-carbon electrode for quick and simple voltametric determination of Zn(II) ions using the SW-ASV method. BiOCl-MWCNT/GCE showed a linear analytical response in a concentration from 2.50 to 80.0 μg dm -3 with a value of detection limit 0.75 μg dm -3 at a acumulation time of 120 s and an electrodeposition potential of -1.40 V vs. saturated calomel electrode. Measurements were carried out in acetate buffer pH 4.5. The obtained value of the RSD was 4.8%. The performance of the newly designed BiOCl-MWCNT/GCE electrode, traditional bismuth-based electrode (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE and unmodified GC electrodes were compared. The applied electrode shows very good electroanalytic properties when determining this target ion. Obtained results are in good agreement with declared value in case of dietetic suplement, and in the brewer’s yeast sample results were comparable with FAAS results. Carbon paste electrode surface modified with new composite material based on multiwalled carbon nanotubes and Sb2O3 particles. The composite is characterized by TEM, EDS and XRD measurment. Sb2O3- MWCNT/CPE was characterized by cyclic voltammetry and measurements were carried out in a hydrochloric acid solution (pH 2.0). Using the SWASV method, this working electrode was used to determine Pb(II), Cd(II) ions in the concentration range from 2.0 to 40.0 μg dm -3 for Pb(II) and 2.0-40.0 μg dm -3 for Cd(II) ions. Newly designed sensor showed good linear dependences for both target ions. The most optimal procedure involving application of Sb2O3-MWCNT/CPE in .01 mol dm -3 hydrochloric acid, with electroposition time of target ions 120 s at a electrodeposition potential of -1.2 V. Obtained values of LOD 1,1 μg dm -3 for Cd(II) and for 1,6 μg dm -3 Pb(II) ions. An optimized method based on this type of voltametric sensor has been successfully applied for determination of Cd(II) ion in a spiked tap water sample. Results obtained during this measurment were in tune with expected results. CPE was surface modified using Sb2O3-MWCNT nanocomposite material and tested for direct voltametric determination of imidacloprid in model solutions. In order to achieve the best analytical performance, experimental conditions of measurement such as the pH value of the supporting electrolyte and conditioning of the voltametric sensor surface havebeen optimized. As an optimum pH value of the supporting electrolyte (Britton-Robinson buffer), a pH 7.0 was selected, and the repeating cycles of the cycling process at least 4 times favorably influenced the stability of the voltametric signals. The optimized method was applied for the SW direct cathodic determination of imidacloprid in the concentration range from 1.41 to 32.77 μg cm -3 with obtained correlation factor of 0.9995. Based on results it can be concluded that developed analytical methods are sensitive, selective, reproducibile and simple, which can enable their application for various number of samples. Measurements in the model and real solutions have demonstrated the possibility of their application in complicated matrices, at different pH, whereby obtained results are in accordance with the results of the applied comparative methods. For obtainig of representative results it is necessary to optimize conditions of measurment which include: selection of substrat electrode, surface modifier and optimization of experimental condition
Voltammetric methods based on carbon electrodes modified with multi walled carbon nanotubes and bismuth and antimony particles based composites for determination of selected target analytes
Cilj ove doktorske disertacija bio je razvoj novih, osetljivih, selektivnih i ekonomski isplativih voltametrijskih radnih elektroda za praćenje odabranih analita kako u laboratorijskim tako i pri terenskim uslovima. Ispitivana je mogućnost primene ovih radnih elektroda primenom voltametrijskih metoda kako u model rastvorima tako i u pojedinim realnim sistemima. SW-ASV zasnovana na elektrodama od staklastog ugljenika površinski modifikovanim Bi-MWCNT i BiOCl-MWCNT je primenjena za određivanje jona Pb(II) i Cd(II) pri optimizovanim uslovima merenja. Određivanje ciljnih jona vršeno je pri radnom potencijalu od -1,2 V (izmeren u odnosu na zasićenu kalomelovu elektrodu) i vremenu elektrodepozicije jona od 120 s. Sva merenja su izvršena u rastvoru acetatnog pufera čija je pH-vrednost iznosila 4,0. Primenjeni koncentracioni opseg ciljnih analita iznosio je od 5 do 50 μg dm -3 . Primenom ovog tipa elektrode dobijene su vrednosti granice detekcije za jone Pb(II) i Cd(II) 0,57 μg dm -3 i 1,2 μg dm-3 , redom. Dobijena RSD iznosila je manje od 10% za oba jona. Ova metoda je primenjena i za određivanje ciljnih jona u realnom uzorku porne vode sedimenta a rezultati dobijeni optimizovanom voltametrijskom metodom su u dobroj saglasnosti sa rezultatima koji su dobijeni primenom komparativne GFAAS metode. Bizmut oksihlorid-višezidne ugljenične nanocevi kompozitni materijal je primenjen za površinsko modifikovanje elektrode od staklastog ugljenika za brzo i jednostavno voltametrijsko određivanje tragova Zn(II)-jona primenom SW-ASV metode. BiOClMWCNT/GCE je pokazala linearan analitički odgovor u osegu koncentracija od 2,50 do 80,0 μg dm -3 sa dobijenom vrednošću GD 0,75 μg dm-3 pri akumulacionom vremenu od 120 s i potencijalu elektrodepozicije -1,40 V u odnosu na ZKE. Merenja su vršena u acetatnom puferu pH 4,5. Dobijena RSD iznosila je 4,8 %. Upoređene su performanse novodizajnirane BiOCl-MWCNT/GCE elektrode i tradicionalne elektrode na bazi bizmut filma (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE i nemodifikovane GC elektrode. Novodizajnirana elektroda je primenjena za detekciju i određivanje Zn(II)-jona u realnim uzorcima kao što su dijetetski suplement i pekarski kvasac. Dobijeni rezultati su uporedivi sa deklarisanom vrednošću u slučaju dijetetskog suplementa a u slučaju pekarskog kvasca sa rezultatima dobijenih komparativnom FAAS . Elektroda od ugljenične paste je površinski modifikovana pripremljenim kompozitom koji je izgrađen od višezidnih ugljeničnih nanocevi i čestica Sb2O3. Kompozitni materijal je okarakterisan primenom TEM, EDS i XRD mernih tehnika. Sb2O3-MWCNT/CPE je okarakterisana primenom ciklične voltametrije a merenja su vršena u rastvoru hlorovodonične kiseline (pH 2,0). Primenom SW-ASV metode ova radna elektroda je upotrebljena za određivanje jona Pb(II) i Cd(II) u koncentracionom opsegu 2,0-40,0 μg dm -3 za Pb(II)-jon i 2,0-40,0 μg dm -3 za Cd(II)-jon pri čemu su dobijene dobre linearne zavisnosti za oba ciljna jona. Optimalna procedura uključuje primenu Sb2O3-MWCNT/CPE u 0,01 mol dm -3 hlorovodoničnoj kiselini uz vreme elektrodepozicije jona iz rastvora od 120 s na potencijaluod -1,2 V, pri čemu su dobijene vrednosti za GD 1,1 μg dm -3 Cd(II) i 1,6 μg dm -3 Pb(II). Optimizovana metoda zasnovana na ovom tipu voltametrijskog senzora je uspešno primenjena za određivanje jona Cd(II) u obogaćenom uzorku česmenske vode, gde su se dobijene vrednosti u saglasnosti sa očekivanom. Elektroda od ugljenične paste površinski je modifikovana primenom Sb2O3-MWCNT nanokompozitnog materijala i primenjena za direktno voltametrijsko određivanje imidakloprida u model rastvorima. U cilju postizanja što boljih analitičkih performansi optimizovani su eksperimentalni uslovi merenja kao što su pH-vrednost rastvora pomoćnog elektrolita i kondicioniranje površine voltametrijskog senzora. Kao optimalna pH-vrednost pomoćnog elektolita (Britton-Robinsonovog pufera) odabrana je pH 7,0, a ponavljanje ciklusa cikliranja najmanje 4 puta povoljno utiče na stabilnost voltametrijskih signala. Optimizovana metoda primenjena je za SW direktno katodno određivanje imidakloprida u koncentracionom intervalu od 1,41 do 32,77 μg cm -3 uz dobijeni korelacioni faktor od 0,9995. Na osnovu dobijenih rezultata može se zaključiti da su razvijene analitičke metode pre svega osetljive, selektivne, reproduktivne i jednostavne što omogućava njihovu primenu za veliki broj uzoraka. Merenjima u model i realnim rastvorima dokazana je mogućnost njihove primene u komplikovanim matriksima, pri različitim pH vredostima pri čemu su dobijeni rezultati koji su u saglasnosti sa rezultatima primenjenih komparativnih metoda. Naravno, za dobijanje reprezentativnih rezultata neohodno je izvršiti optimizaciju uslova merenja što podrazumeva sam odabir supstrat-elektrode, odabir površinskog modifikatora i optimizaciju eksperimentalnih uslova merenja.The aim of this Ph.D. thesis was the development of new, sensitive, selective and economically viable voltametric working electrode for continuous monitoring of different target analytes. The use of these advantaged working electrodes was investigated using voltametric methods both in model solutions and in certain real systems.SW-ASV based on glassy carbon electrode surface modified with Bi- MWCNT and BiOCl-MWCNT were applied for determination of Pb(II) and Cd(II) ions. Voltametric determination of Pb(II) and Cd(II) ions was performed at working potential of -1.2 V (measured against the saturated calomel electrode) and time of electrodeposition of 120 s. All measurements were performed in acetate buffer solution pH 4.0. Concentration range of targetanalites were 5-50 μg dm -3 . Using this type of electrode, obtained detection limits for Pb(II) and Cd(II) ions were 0.57 μg dm -3 and 1.2 μg dm -3 , respectively, with RSD lower than 10%.This method was applied for target ions determination in sediment pore water sample, and obtained results are comparable with those who are obtained using GFAAS method. Bismuth oxychloride-multiwalled carbon nanotubes composite material was applied for surface modification of the glass-carbon electrode for quick and simple voltametric determination of Zn(II) ions using the SW-ASV method. BiOCl-MWCNT/GCE showed a linear analytical response in a concentration from 2.50 to 80.0 μg dm -3 with a value of detection limit 0.75 μg dm -3 at a acumulation time of 120 s and an electrodeposition potential of -1.40 V vs. saturated calomel electrode. Measurements were carried out in acetate buffer pH 4.5. The obtained value of the RSD was 4.8%. The performance of the newly designed BiOCl-MWCNT/GCE electrode, traditional bismuth-based electrode (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE and unmodified GC electrodes were compared. The applied electrode shows very good electroanalytic properties when determining this target ion. Obtained results are in good agreement with declared value in case of dietetic suplement, and in the brewer’s yeast sample results were comparable with FAAS results. Carbon paste electrode surface modified with new composite material based on multiwalled carbon nanotubes and Sb2O3 particles. The composite is characterized by TEM, EDS and XRD measurment. Sb2O3- MWCNT/CPE was characterized by cyclic voltammetry and measurements were carried out in a hydrochloric acid solution (pH 2.0). Using the SWASV method, this working electrode was used to determine Pb(II), Cd(II) ions in the concentration range from 2.0 to 40.0 μg dm -3 for Pb(II) and 2.0-40.0 μg dm -3 for Cd(II) ions. Newly designed sensor showed good linear dependences for both target ions. The most optimal procedure involving application of Sb2O3-MWCNT/CPE in .01 mol dm -3 hydrochloric acid, with electroposition time of target ions 120 s at a electrodeposition potential of -1.2 V. Obtained values of LOD 1,1 μg dm -3 for Cd(II) and for 1,6 μg dm -3 Pb(II) ions. An optimized method based on this type of voltametric sensor has been successfully applied for determination of Cd(II) ion in a spiked tap water sample. Results obtained during this measurment were in tune with expected results. CPE was surface modified using Sb2O3-MWCNT nanocomposite material and tested for direct voltametric determination of imidacloprid in model solutions. In order to achieve the best analytical performance, experimental conditions of measurement such as the pH value of the supporting electrolyte and conditioning of the voltametric sensor surface havebeen optimized. As an optimum pH value of the supporting electrolyte (Britton-Robinson buffer), a pH 7.0 was selected, and the repeating cycles of the cycling process at least 4 times favorably influenced the stability of the voltametric signals. The optimized method was applied for the SW direct cathodic determination of imidacloprid in the concentration range from 1.41 to 32.77 μg cm -3 with obtained correlation factor of 0.9995. Based on results it can be concluded that developed analytical methods are sensitive, selective, reproducibile and simple, which can enable their application for various number of samples. Measurements in the model and real solutions have demonstrated the possibility of their application in complicated matrices, at different pH, whereby obtained results are in accordance with the results of the applied comparative methods. For obtainig of representative results it is necessary to optimize conditions of measurment which include: selection of substrat electrode, surface modifier and optimization of experimental condition
TGFB1 Gene Promoter Polymorphisms in Serbian Asthmatics
Background. Asthma is a chronic respiratory disease caused by a combination of genetic and environmental factors. Transforming growth factor beta 1 (TGFB1) is a multifunctional cytokine that plays an important role in airway remodeling in asthma. Objectives. The aim of this study was to analyze common TGFB1 gene promoter polymorphisms C-509T and G-800A in Serbian asthmatics and to investigate their association with exacerbations. Material and Methods. The study involved 102 asthmatics and 58 healthy individuals from Serbia, age and gender matched. An analysis of the TGFB1 promoter was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results. For polymorphism C-509T a significant difference in the allele frequency was observed between the patients and the controls (p = 0.011), while the genotype distribution was similar in the analyzed groups, with statistical significance near the borderline (p = 0.061). For the polymorphism G-800A no difference was observed between the groups. The frequency of the -509TT genotype was higher in patients with exacerbations compared to patients without exacerbations (36.4% vs. 17.0%), with statistical significance near the borderline (p = 0.080). Conclusions. The results suggest that polymorphism C-509T may be associated with asthma and disease exacerbations, while G-800A is not significant for the etiology and clinical course of the disease. These findings should be confirmed in a larger study group, and since the TGFB1 promoter is highly complex and very responsive to environmental factors, future studies should also take other genetic and non-genetic factors into consideration
Quantitative Determination of Pesticides in Soil by Thin-layer Chromatography and Video Densitometry
Reversed phase thin-layer chromatography (RP-TLC) in conjunction with video densitometry has been used for the quantitative determination of a six-component mixture of pesticides. Excellent separation of propham, chlorpropham, atrazine, diflubenzuron, tetramethrin and α-cypermethrin was achieved using the methanol/water solvent system (volume fraction of methanol, φ = 80%). Video densitometric quantification was validated for linearity, precision and detection limit. All results were satisfactory according to the validation requirements. The method was tested for the determination of pesticides from spiked soil using ultrasonic extraction with various solvents
Different sensibility of ecto-ATPase from brain and ovary to Cu2+ and Zn2+
Ions of zinc and cooper represents micro elements present in all organisms but they can be accumulated in various tissues from the environment by food or pollution. In this work we examined the effects of chloride salts of Cu2+ and Zn2+ on the activity of ecto-ATPase, integral plasma membrane protein, in brain and ovarian cells. Both ions exhibit similar effects on brain or ovarian enzyme activity. Cooper in brain and ovary totally inhibits enzyme activity at the concentration of 1 mM and 0.1 M respectively. IC50 for brain is 36 µM while in ovary it is 192 µM. Zinc inhibits in both tissues 50% of the control enzyme activity at concentrations of 1 mM in brain and 0.1 M in ovary with IC50 of 1mM and 14 mM respectively. These metals possess an affinity for -SH groups in the enzyme protein, may replace Mg2+ in enzyme substrate, MgATP or to bind for enzyme substrate site. According to the total inhibition of ecto-ATPase activity by Cu 2+, it may be proposed that its site of action is on the substrate or substrate binding site, while Zn2+ modulates enzyme activity by acting on the –SH or S-S groups of the enzyme. Inhibiting or decreasing ecto-ATPase activity in brain and ovary, these two metal ions may be toxic and seriously disturb the proper functioning of the investigated tissues.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
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