Temat: cytochrome p-450 - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Toxicological and cytophysiological aspects of lanthanides action.
Autorzy:: Pałasz, Artur
Czekaj, Piotr
Powiązania:: https://bibliotekanauki.pl/articles/1044234.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: gadolinium
cytochrome P450.
calcium
lanthanides
metals
Opis:: Lanthanides, also called rare-earth elements, are an interesting group of 15 chemically active, mainly trivalent, f-electronic, silvery-white metals. In fact, lanthanides are not as rare as the name implies, except for promethium, a radioactive artificial element not found in nature. The mean concentrations of lanthanides in the earth's crust are comparable to those of life-important elements like iodine, cobalt and selenium. Many lanthanide compounds show particular magnetic, catalytic and optic properties, and that is why their technical applications are so extensive. Numerous industrial sources enable lanthanides to penetrate into the human body and therefore detailed toxicological studies of these metals are necessary. In the liver, gadolinium selectively inhibits secretion by Kupffer cells and it decreases cytochrome P450 activity in hepatocytes, thereby protecting liver cells against toxic products of xenobiotic biotransformation. Praseodymium ion (Pr3+) produces the same protective effect in liver tissue cultures. Cytophysiological effects of lanthanides appear to result from the similarity of their cationic radii to the size of Ca2+ ions. Trivalent lanthanide ions, especially La3+ and Gd3+, block different calcium channels in human and animal cells. Lanthanides can affect numerous enzymes: Dy3+ and La3+ block Ca2+-ATPase and Mg2+-ATPase, while Eu3+ and Tb3+ inhibit calcineurin. In neurons, lanthanide ions regulate the transport and release of synaptic transmitters and block some membrane receptors, e.g. GABA and glutamate receptors. It is likely that lanthanides significantly and uniquely affect biochemical pathways, thus altering physiological processes in the tissues of humans and animals.
Źródło:: Acta Biochimica Polonica; 2000, 47, 4; 1107-1114
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Skin metabolism established with the use of MetaSite for selected retinoids employed in topical and systemic treatment of various skin disorders and found in cosmeceuticals
Autorzy:: Słoczyńska, Karolina
Gunia-Krzyżak, Agnieszka
Żelaszczyk, Dorota
Waszkielewicz, Anna
Marona, Henryk
Powiązania:: https://bibliotekanauki.pl/articles/1039091.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: cytochrome P450
MetaSite
retinoids
skin metabolism
Opis:: Purpose. Besides being widely used in cosmetics, retinoids are potent therapeutic agents used topically and systemically as anti-acne agents. The aim of this study was to predict with the use of MetaSite the skin metabolism of selected retinoids employed in treatment of skin disorders and found in cosmeceuticals. The following compounds were studied: retinol, retinaldehyde, retinoic acid, retinyl acetate, retinyl palmitate, acitretin, etretinate, adapalene and bexarotene. Methods. MetaSite, Molecular Discovery Ltd. is a computational model that enables prediction of cytochrome P450-dependant metabolism. This software indicates atoms in the molecule structure that are mostly vulnerable to metabolic changes and predicts the metabolite structures. Results. MetaSite indicated that retinol and retinal metabolites were obtained through hydroxylation of the methyl group located in the position 3 of the aliphatic chain, whereas retinoic acid biotransformation would occur principally in the carbon atom situated in the position 4 in the cyclohexene ring. In acitretin molecule, carbon atom of the methoxy group attached to the benzene ring displayed the highest probability of biotransformation. In etretinate, metabolic reactions would occur principally on the carbon atom of the final ethyl group of the molecule. Conclusions. MetaSite metabolism predictions for retinoic acid, acitretin, etretinate, adapalene and bexarotene were in agreement with experimental findings. In case of compounds being converted by catalysts other than cytochrome P450 enzymes, the primary metabolites predicted by MetaSite differ from those reported previously. In conclusion, MetaSite is a useful tool that can aid identification of the major metabolites of compounds being administered topically.
Źródło:: Acta Biochimica Polonica; 2015, 62, 2; 201-206
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of acetaminophen and trichloroethylene on liver cytochrome P450-dependent monooxygenase system.
Autorzy:: Plewka, Andrzej
Zielińska-Psuja, Barbara
Kowalówka-Zawieja, Joanna
Nowaczyk-Dura, Grażyna
Plewka, Danuta
Wiaderkiewicz, Anna
Kamiński, Marcin
Orłowski, Jerzy
Powiązania:: https://bibliotekanauki.pl/articles/1044264.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: trichloroethylene
liver
rat
acetaminophen
cytochrome P450,glutathione
Opis:: The aim of the study was to evaluate the effect of acetaminophen (APAP) and/or trichloroethylene (TRI) on the liver cytochrome P450-dependent monooxygenase system, CYP2E1 and CYP1A2 (two important P450 isoforms), and liver glutathione (GSH) content in rats. Rats were given three different doses of APAP (250, 500 and 1000 mg/kg b...) and then the above-mentioned parameters were measured for 48 h. The lowest APAP dose produced small changes in the cytochrome P450 content of liver. At 500 mg/kg APAP increased the cytochrome P450 content to 230% of the control. The inductive effect was seen at 1000 mg/kg dose but at 24 h and later. NADPH-cytochrome P450 reductase activity was the highest after the lowest dose of APAP, while after the highest dose it was equal to the control value. TRI increased both the cytochrome P450 content and the NADPH-cytochrome P450 reductase activity. When TRI was combined with APAP, both these parameters increased in the first hours of observation, but they returned to the control values at 24 h. When APAP was given at 250 mg/kg, GSH levels decreased to 55% of the control at 8 h and returned to the control values at 24 h. The higher doses of APAP decreased GSH levels more than the lowest dose, but after 24 h GSH levels did not differ from those of the control. When TRI was given at 250 mg/kg, the GSH levels decreased to 68% of the control at 2 h and then they increased gradually and tended to exceed the control values at 48 h. The effect of TRI combined with APAP on the level of GSH was virtually the same as that of APAP alone given at 500 mg/kg.
Źródło:: Acta Biochimica Polonica; 2000, 47, 4; 1129-1136
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Arterial ketone index in assessing liver function and its detoxicative capability after ischemia-reperfusion injury.
Autorzy:: Caban, Artur
Wiaderkiewicz, Ryszard
Kamiński, Marcin
Oczkowicz, Grzegorz
Ziaja, Jacek
Powiązania:: https://bibliotekanauki.pl/articles/1044266.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: ischemia
arterial ketone index
cytochrome P450
reperfusion
Opis:: Arterial ketone index (AKBR) which is the ratio of acetoacetic acid to 3-hydroxybutyric acid in the arterial blood, is believed to reflect the mitochondrial reduction potential of hepatocytes and general energy state of the liver. In the presented paper we challenged this hypothesis by analysing the correlation between AKBR and the results of typical liver blood tests (AspAT, AlAT, LDH, CRP) and biotransforming potential of the liver (cytochromes P450, b5 and their corresponding NADPH and NADH reductases) in the model of ischemia-reperfusion injury of rat liver. The results were compared with histochemical analysis of distribution and activity of SDH, LDH and G-6-Pase, the key marker enzymes of the liver. We have shown that, except in the case of acute phase protein (CRP), a decrease in AKBR correlated well with the increase of the level of indicator enzymes in serum. Histochemical analysis also confirmed that AKBR correlates with the degree of damage to hepatocytes during early stage of reperfusion after 60 min of liver ischemia. In the Spearman test, AKBR was significantly correlated with the changes in cytochrome P450 content and its NADPH reductase activity which indicates a high sensitivity of this test. We conclude that the decrease of AKBR value reflects the impairment of basic energy pathways and detoxicative capability of the liver.
Źródło:: Acta Biochimica Polonica; 2000, 47, 4; 1137-1146
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Metabolic activation of adriamycin by NADPH-cytochrome P450 reductase; overview of its biological and biochemical effects.
Autorzy:: Bartoszek, Agnieszka
Powiązania:: https://bibliotekanauki.pl/articles/1043757.pdf
Data publikacji:: 2002
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: covalent binding to macromolecules
adriamycin
oxygen radicals
NADPH-cytochrome P450 reductase
Opis:: NADPH-cytochrome P450 reductase (P450 reductase) is one of the enzymes implicated in the metabolism of adriamycin, a very important clinically used antitumour drug. However, apart from the enzyme involvement, so far little was known about the chemical route and biochemical effects of this process. We demonstrated that the application of P450 reductase simultaneously with adriamycin to tumour cells in culture significantly increased cytotoxicity of the drug. Under tissue culture conditions, we noticed also that, in the presence of P450 reductase, adriamycin metabolite(s), displaying an altered spectrum within the visible light range were formed. This observation was taken adavantage of to study the metabolism of adriamycin in cell-free systems, using initially the enzyme isolated from rat liver and the recently obtained recombinant human P450 reductase. The reductive conversion of the drug turned out to be a multi-stage process, which occurred only under aerobic conditions and was accompanied by excessive NADPH consumption. Further research carried out with the aid of radical scavengers and radiolabelled adriamycin revealed that the enhancement of biological activity of adriamycin by P450 reductase stemmed from the formation of alkylating metabolite(s) rather than from the promotion of redox cycling known to be induced in the presence of anthracyclines.
Źródło:: Acta Biochimica Polonica; 2002, 49, 2; 323-331
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Use of cell therapy as a means of targeting chemotherapy to inoperable pancreatic cancer
Autorzy:: Günzburg, Walter
Salmons, Brian
Powiązania:: https://bibliotekanauki.pl/articles/1041363.pdf
Data publikacji:: 2005
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: cytochrome P450
chemotherapy
genetically modified cells
cell therapy
encapsulated cells
pancreatic cancer
Opis:: Although approved for the treatment of pancreatic cancer, the chemotherapeutic agent ifosfamide is not an effective therapy for this type of tumour. Ifosfamide must be activated by cytochrome P450 (P450) enzymes in the liver, initially to a short lived intermediate and then to toxic metabolites that are subsequently distributed by the circulatory system. Particularly for pancreatic cancer, this liver-mediated conversion results in relatively high systemic toxicities and poor therapeutic concentrations at the liver-distant site of the tumour. Activation of ifosfamide at the site of the tumour may allow lower doses to be used, while increasing the therapeutic index due to the resultant active concentrations generated locally. A cell-based therapy has been conceived where encapsulated, 293-derived cells genetically modified to overexpress a cytochrome P450 enzyme, are implanted near solid tumours. The cells are encapsulated in polymers of cellulose sulphate in order to provide a means of immunoprotection in vivo as well as to physically constrain them to the vicinity of the tumour. A major advantage of this strategy is that it allows one standard cell line to be applied to all patients and this approach can be extended to the treatment of other tumour types. After proof of principle studies in animal models, a phase I/II clinical trial was initiated in patients with stage III/IV nonresectable pancreatic cancer. Encapsulated cells were angiographically placed into the tumour vasculature of 14 patients and followed by systemic low dose ifosfamide treatment. Angiographic delivery of encapsulated cells proved feasible in all but one patient, and was well tolerated with no capsule or ifosfamide treatment-related adverse events. Four of the treated patients showed tumour regressions after capsule delivery and ifosfamide treatment in computer-tomography scans. The other 10 patients showed no further tumour growth (i.e. stable disease) during 20 weeks observation period. The median life expectancy of the patient collective was extended two fold as compared to age and status matched historical controls, with a 3-fold improvement in one year survival being attained. Evidence for a clinical benefit of the treatment was also obtained on the basis of standard parameters for quality of life. This approach has been evaluated by the European Medicines Evaluation Agency (EMEA) and orphan drug status has been granted. A pivotal clinical trial is now being planned with the help of the EMEA. Taken together, the data from this clinical trial suggest that encapsulated cytochrome P450-expressing cells combined with chemotherapy may be useful for the local treatment of a number of solid tumours and support the performance of further clinical studies of this new treatment.
Źródło:: Acta Biochimica Polonica; 2005, 52, 3; 601-607
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Bidirectional regulation of renal cortical Na+,K+-ATPase by protein kinase C.
Autorzy:: Bełtowski, Jerzy
Marciniak, Andrzej
Jamroz-Wiśniewska, Anna
Borkowska, Ewelina
Wójcicka, Grażyna
Powiązania:: https://bibliotekanauki.pl/articles/1041555.pdf
Data publikacji:: 2004
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: phosphatidylinositol-3-kinase
protein kinase C
cytochrome P450-dependent arachidonate metabolites
Na+,K+-ATPase
Opis:: We examined the role of protein kinase C (PKC) in the regulation of Na+,K+- ATPase activity in the renal cortex. Male Wistar rats were anaesthetized and the investigated reagents were infused into the abdominal aorta proximally to the renal arteries. A PKC-activating phorbol ester, phorbol 12,13-dibutyrate (PDBu), had a dose-dependent effect on cortical Na+,K+-ATPase activity. Low dose of PDBu (10-11 mol/kg per min) increased cortical Na+,K+-ATPase activity by 34.2%, whereas high doses (10-9 and 10-8 mol/kg per min) reduced this activity by 22.7% and 35.0%, respectively. PDBu administration caused changes in Na+,K+-ATPase Vmax without affecting K0.5 for Na+, K+ and ATP as well as Ki for ouabain. The effects of PDBu were abolished by PKC inhibitors, staurosporine, GF109203X, and Gö 6976. The inhibitory effect of PDBu was reversed by pretreatment with inhibitors of cytochrome P450-dependent arachidonate metabolism, ethoxyresorufin and 17-octadecynoic acid, inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin and LY294002, and by actin depolymerizing agents, cytochalasin D and latrunculin B. These results suggest that PKC may either stimulate or inhibit renal cortical Na+,K+-ATPase. The inhibitory effect is mediated by cytochrome P450-dependent arachidonate metabolites and PI3K, and is caused by redistribution of the sodium pump from the plasma membrane to the inactive intracellular pool.
Źródło:: Acta Biochimica Polonica; 2004, 51, 3; 757-772
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Expression of cytochrome CYP2B1/2 in nonpregnant, pregnant and fetal rats exposed to tobacco smoke.
Autorzy:: Czekaj, Piotr
Wiaderkiewicz, Anna
Florek, Ewa
Wiaderkiewicz, Ryszard
Powiązania:: https://bibliotekanauki.pl/articles/1044235.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: pregnancy
CYP2B6
rats
cytochrome P450
CYP2B1/2
tobacco smoke
Opis:: Four-month-old female Wistar rats were exposed for 20 days to tobacco smoke obtained from non-filter cigarettes. During the exposure, concentration of tobacco smoke was monitored indirectly by measuring the CO level (1500 mg/m3 air). The efficacy of exposure was assessed by measuring urine nicotine and cotinine levels. Cigarette smoke did not change total cytochrome P450 and b5 protein levels in any of the organs studied, and most of these organs did not show any changes in the activity of reductases associated with these cytochromes. Following exposure to tobacco smoke, fetal rat liver expressed CYP2B1/2 protein; in newborns (day 1) both liver and lung showed CYP2B1/2 protein expression and very low pentoxyresorufin O-dealkylase activity. Western blot analysis of adult liver, lung, heart, but not of brain microsomes, showed that tobacco smoke induced CYP2B1/2 in both nonpregnant and pregnant rats, though its expression was lower in the livers and hearts of pregnant females. In the rat and human placenta, neither rat CYP2B1/2 nor human CYP2B6 showed basal or tobacco smoke-induced expression at the protein level. This study shows clearly that the expression of CYP2B1/2, which metabolizes nicotine and some drugs and activates carcinogens, is controlled in rats by age-, pregnancy-, and tissue-specific regulatory mechanisms.
Źródło:: Acta Biochimica Polonica; 2000, 47, 4; 1115-1127
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Regulation of renal Na+,K+ -ATPase and ouabain-sensitive H+,K+ -ATPase by the cyclic AMP-protein kinase A signal transduction pathway.
Autorzy:: Bełtowski, Jerzy
Marciniak, Andrzej
Wójcicka, Grażyna
Górny, Dionizy
Powiązania:: https://bibliotekanauki.pl/articles/1043651.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: kidney
cyclic AMP
protein kinase A
cytochrome P450-dependent arachidonate metabolites
Na+,K+ -ATPase
H+,K+ -ATPase
Opis:: We investigated the effect of the cyclic AMP-protein kinase A (PKA) signalling pathway on renal Na+,K+-ATPase and ouabain-sensitive H+,K+-ATPase. Male Wistar rats were anaesthetized and catheter was inserted through the femoral artery into the abdominal aorta proximally to the renal arteries for infusion of the investigated substances. Na+,K+-ATPase activity was measured in the presence of Sch 28080 to block ouabain-sensitive H+,K+-ATPase and improve specificity of the assay. Dibutyryl-cyclic AMP (db-cAMP) administered at a dose of 10-17 mol/kg per min and 10-6 mol/kg per min increased Na+,K+-ATPase activity in the renal cortex by 34% and 42%, respectively, and decreased it in the renal medulla by 30% and 44%, respectively. db-cAMP infused at 10-6 mol/kg per min increased the activity of cortical ouabain-sensitive H+,K+-ATPase by 33%, and medullary ouabain-sensitive H+,K+-ATPase by 30%. All the effects of db-cAMP were abolished by a specific inhibitor of protein kinase A, KT 5720. The stimulatory effect on ouabain-sensitive H+,K+-ATPase and on cortical Na+,K+-ATPase was also abolished by brefeldin A which inhibits the insertion of proteins into the plasma membranes, whereas the inhibitory effect on medullary Na+,K+-ATPase was partially attenuated by 17-octadecynoic acid, an inhibitor of cytochrome P450-dependent arachidonate metabolism. We conclude that the cAMP-PKA pathway stimulates Na+,K+-ATPase in the renal cortex as well as ouabain-sensitive H+,K+-ATPase in the cortex and medulla by a mechanism requiring insertion of proteins into the plasma membrane. In contrast, medullary Na+,K+-ATPase is inhibited by cAMP through a mechanism involving cytochrome P450-dependent arachidonate metabolites.
Źródło:: Acta Biochimica Polonica; 2003, 50, 1; 103-114
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Phenobarbital-induced expression of cytochrome P450 genes.
Autorzy:: Czekaj, Piotr
Powiązania:: https://bibliotekanauki.pl/articles/1044233.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: CYP2B
cytochrome P450
phenobarbital-responsive enhancer unit
CYP2H1.
orphan receptors
CYP3A
PXR
CAR
phenobarbital
Opis:: In contrast to the well-known Ah receptor-mediated regulation of the CYP1A1 gene by polycyclic aromatic hydrocarbons, the molecular mechanism by which phenobarbital (PB) and PB-like inducers affect transcription of CYP genes remains unknown; no receptor for these chemicals has been found to date. However, in the last 5 years PB-responsive sequences have been identified in the 5' flanking regions of several P450 genes. The phenobarbital-responsive enhancer unit (PBRU) of CYP2B gene family members contain two potential nuclear receptor binding sites (NR1 and NR2) that flank a nuclear factor 1 (NF-1) binding motif. The nuclear factors that regulate PBRU activity have not yet been characterized. It seems that PB may activate multiple nuclear orphan receptors to induce various CYP genes. CYP2B and CYP3A genes appear to be targets for the orphan receptors CAR and PXR, respectively. It is also possible that the pleiotropic effects of PB can, in part, be explained by the ability of the CAR-RXR heterodimer to bind to a variety of nuclear receptor binding motifs. The induction of cytochromes P450 may result in interactions between xenobiotics and in the interference of xenobiotic metabolism and endogenous signalling pathways.
Źródło:: Acta Biochimica Polonica; 2000, 47, 4; 1093-1105
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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