Effects of cytochrome P450 single nucleotide polymorphisms on methadone metabolism and pharmacodynamics

Methadone is a synthetic, long-acting opioid with a single chiral center forming two enantiomers, (R)-methadone and (S)-methadone, each having specific pharmacological actions. Concentrations of (R)- and (S)-methadone above therapeutic levels have the ability to cause serious, life-threatening, and fatal side effects. This toxicity can be due in part to the pharmacogenetics of an individual, which influences the pharmacokinetic and pharmacodynamic properties of the drug. Methadone is primarily metabolized in the liver by cytochrome P450 (CYP) enzymes, predominately by CYP2B6, followed by CYP3A4, 2C19, 2D6, and to a lesser extent, CYP2C18, 3A7, 2C8, 2C9, 3A5, and 1A2. Single nucleotide polymorphisms (SNPs) located within CYPs have the potential to play an important role in altering methadone metabolism and pharmacodynamics. Several SNPs in the CYP2B6, 3A4, 2C19, 2D6, and 3A5 genes result in increases in methadone plasma concentrations, decreased N-demethylation, and decreased methadone clearance. In particular, carriers of CYP2B6*6/*6 may have a greater risk for detrimental adverse effects, as methadone metabolism and clearance are diminished in these individuals. CYP2B6*4, on the other hand, has been observed to decrease plasma concentrations of methadone due to increased methadone clearance. The involvement, contribution, and understanding the role of SNPs in CYP2B6, and other CYP genes, in methadone metabolism can improve the therapeutic uses of methadone in patient outcome and the development of personalized medicine

Self-Reported Tobacco Use and Correlation with Umbilical Cord Blood Cotinine levels at Delivery among Appalachian Gravidas

The detrimental effects of cigarette use during pregnancy are well documented. Studies have shown that cigarette smoking while pregnant is associated with multiple adverse outcomes including: pre-term birth, placental abruption, placenta previa, fetal growth restriction, stillbirth, increased rate of birth defects, and increased risk of sudden infant death syndrome. Cotinine is the primary metabolite of nicotine and allows for measurement of active as well as passive exposure. Cotinine freely cross the placental barrier and maternal concentrations are closely correlated with newborn plasma levels. The aim of this study was to compare maternally reported rates of tobacco use to fetal umbilical cord blood cotinine levels at the time of delivery. A cross-sectional study was conducted on 172 patients. Patients were asked a single yes or no question in regards to their cigarette use during pregnancy. Cord blood was collected at the time of delivery and analyzed for serum concentrations of cotinine. Cotinine levels greater than 3.0 ng/mL were considered consistent with the use of tobacco or tobacco cessation products. Maternal self-reporting of tobacco use indicates a reported tobacco use rate of 27.3% and an actual use rate of 30.2%. The reported tobacco non-use rate was 72.7% and the actual non-use rate was 66.3%. The prevalence of tobacco use during pregnancy in our study was 30.2%, while the overall rate in the United States is reported to be 12.3%. Our findings indicate that self-reported smoking prevalence and verified umbilical cord blood cotinine levels at the time of delivery have excellent correlation (kappa=0.76). Compared to the national average our study group also had nearly double the rate of tobacco use. Due to the deleterious effects of cigarette use during pregnancy continued efforts to educate patients regarding cigarette cessation is of utmost importance as cessation of tobacco products will improve and promote maternal and fetal well-being

Self-Reported Tobacco Use and Correlation with Umbilical Cord Blood Cotinine levels at Delivery among Appalachian Gravidas

The detrimental effects of cigarette use during pregnancy are well documented. Studies have shown that cigarette smoking while pregnant is associated with multiple adverse outcomes including: pre-term birth, placental abruption, placenta previa, fetal growth restriction, stillbirth, increased rate of birth defects, and increased risk of sudden infant death syndrome. Cotinine is the primary metabolite of nicotine and allows for measurement of active as well as passive exposure. Cotinine freely cross the placental barrier and maternal concentrations are closely correlated with newborn plasma levels. The aim of this study was to compare maternally reported rates of tobacco use to fetal umbilical cord blood cotinine levels at the time of delivery. A cross-sectional study was conducted on 172 patients. Patients were asked a single yes or no question in regards to their cigarette use during pregnancy. Cord blood was collected at the time of delivery and analyzed for serum concentrations of cotinine. Cotinine levels greater than 3.0 ng/mL were considered consistent with the use of tobacco or tobacco cessation products. Maternal self-reporting of tobacco use indicates a reported tobacco use rate of 27.3% and an actual use rate of 30.2%. The reported tobacco non-use rate was 72.7% and the actual non-use rate was 66.3%. The prevalence of tobacco use during pregnancy in our study was 30.2%, while the overall rate in the United States is reported to be 12.3%. Our findings indicate that self-reported smoking prevalence and verified umbilical cord blood cotinine levels at the time of delivery have excellent correlation (kappa=0.76). Compared to the national average our study group also had nearly double the rate of tobacco use. Due to the deleterious effects of cigarette use during pregnancy continued efforts to educate patients regarding cigarette cessation is of utmost importance as cessation of tobacco products will improve and promote maternal and fetal well-being

Istraživanje mehanizma toksičnosti anilina u eritrocitima

Strategies for the use of bio-indicators in the prediction of environmental damage should include mechanistic research. This study involves the relationship between the chemical structure and hemotoxic markers of aniline and its halogenated analogs. Aniline-induced methemoglobinemia, loss of circulating blood cells, blood stability, glutathione depletion and membrane cytoskeletal changes were assessed following exposure to phenylhydroxylamine (PHA), para-fluoro-, para-bromo-, and para-iodo in male Sprague-Dawley rats. Methemoglobin was determined spectrophotometrically at 635 nm. Erythrocyte depletion was investigated by loss of radioactivity in chromium-labeled red blood cells in vivo. Membrane proteins were analyzed by SDS-PAGE using red blood ghost cells treated with various aniline analogs. Results showed dose- and time-dependent changes in the induction of methemoglobin of up to 78 % with para-bromo PHA and 75 % with para-iodo PHA compared to 3 % to 5 % in control. Treated animals lost up to three times more blood from circulation compared to control within 14 days after treatment. Erythrocytes were more stable in buffer solution than in para-iodo-treated cells. Depletion of reduced glutathione in PHA and para-iodo-PHA treated red cells was also observed. Analysis of red cell skeletal membrane treated with para-iodo-PHA showed that protein band 2.1 became broader and band 2.2 diminished completely in some treatments. Dose- and time-dependent changes suggested the use of hemotoxic endpoints as potential biomarkers for assessing chemical and drug safetyStrategije primjene biopokazatelja za predviđanje štete u okolišu trebaju u obzir uzeti istraživanja mehanizama djelovanja. Ovo istraživanje propituje odnos između kemijske strukture i hemotoksičnih pokazatelja djelovanja anilina i njegovh halogeniranih analoga. Nakon izlaganja mužjaka štakora soja Sprague-Dawley para-fluoro-, para-bromo- i para-jodofenilhidroksilaminu, utvrđena je methemoglobinemija uzrokovana anilinom te pad broja krvnih stanica u krvotoku i stabilnosti krvi, gubitak glutationa i promjene na membrani stanice. Methemoglobin je određivan spektrofotometrijski na 635 nm. Pad broja eritrocita mjeren je in vivo s pomoću eritrocita obilježenih radioaktivnim kromom. Membranske su bjelančevine analizirane s pomoću SDS-PAGE, rabeći eritrocite bez hemoglobina (engl. ghost cells) kojima su dodani različiti analozi anilina. Nalazi upućuju na promjene indukcije methemoglobina ovisno o dozi i vremenu djelovanja do 78 % s para-bromo-fenilhidroksilaminom te do 75 % s para-jodofenilhidroksilaminom u usporedbi s 3 % do 5 % u kontrolnih uzoraka. U razdoblju od 14 dana nakon tretiranja izložene životinje izgubile su tri puta više krvi iz krvotoka od kontrolnih. Eritrociti su bili stabilniji u puferskoj otopini negoli u stanicama kojima je dodan para-jodofenilhidroksilamin. Zamijećen je i pad glutationa u eritrocitima kojima je dodan fenilhidroksilamin odnosno para-jodofenilhidroksilamin. Analizom membrane eritrocita kojima je dodan para-jodofenilhidroksilamin zamijećeno je da se u pojedinih obrada raširila proteinska vrpca 2.1, a potpuno smanjila proteinska vrpca 2.2. Zamijećene promjene uvjetovane dozom i vremenom upućuju na primjenu hemotoksičnih parametara kao mogućih biopokazatelja u procjeni sigurnosti lijeka odnosno kemikalije

Drought or/and Heat-Stress Effects on Seed Filling in Food Crops: Impacts on Functional Biochemistry, Seed Yields, and Nutritional Quality

Drought (water deficits) and heat (high temperatures) stress are the prime abiotic constraints, under the current and climate change scenario in future. Any further increase in the occurrence, and extremity of these stresses, either individually or in combination, would severely reduce the crop productivity and food security, globally. Although, they obstruct productivity at all crop growth stages, the extent of damage at reproductive phase of crop growth, mainly the seed filling phase, is critical and causes considerable yield losses. Drought and heat stress substantially affect the seed yields by reducing seed size and number, eventually affecting the commercial trait ‘100 seed weight’ and seed quality. Seed filling is influenced by various metabolic processes occurring in the leaves, especially production and translocation of photoassimilates, importing precursors for biosynthesis of seed reserves, minerals and other functional constituents. These processes are highly sensitive to drought and heat, due to involvement of array of diverse enzymes and transporters, located in the leaves and seeds. We highlight here the findings in various food crops showing how their seed composition is drastically impacted at various cellular levels due to drought and heat stresses, applied separately, or in combination. The combined stresses are extremely detrimental for seed yield and its quality, and thus need more attention. Understanding the precise target sites regulating seed filling events in leaves and seeds, and how they are affected by abiotic stresses, is imperative to enhance the seed quality. It is vital to know the physiological, biochemical and genetic mechanisms, which govern the various seed filling events under stress environments, to devise strategies to improve stress tolerance. Converging modern advances in physiology, biochemistry and biotechnology, especially the “omics” technologies might provide a strong impetus to research on this aspect. Such application, along with effective agronomic management system would pave the way in developing crop genotypes/varieties with improved productivity under drought and/or heat stresses