Applicator exposure to acetochlor based on biomonitoring

Biomonitoring was used to assess the combined dermal, oral, and inhalation exposure associated with the agricultural use of Harness Plus, an emulsifiable concentrate formulation of the herbicide acetochlor. Twenty Spanish farmers handled and applied acetochlor to maize in the spring of 2003, following the product label recommendations. Open- and closed-cabin applications were equally represented. Urine was collected during six consecutive days, starting the day prior to application. Daily composites were analyzed for 2-ethyl-6-methyl-aniline, a common chemophore representing the major urinary acetochlor metabolites. All applicators showed detectable concentrations in urine after application. Although, the open-cabin applicators treated fewer hectares, they showed significantly higher exposure compared to the closed-cabin applicators (average exposure: 0.004 and 0.002 mg/kg bw/day, respectively). Linear regression analysis suggested that untracked incidents had a significant impact on the total exposure. Other events that may have contributed to the observed exposure are repair of faulty equipment, accidental spillages, splashes, and inadequate use of protective gloves. The average margins of exposure (MOE) for farmers ranged from 23,000 (open cabin) to about 44,000 (closed cabin). For professional applicators the MOEs were 10-fold lower. These MOEs clearly indicate that no adverse health effects should be expected from agricultural acetochlor applications.     

Lefetamine‐derived designer drugs N‐ethyl‐1,2‐diphenylethylamine (NEDPA) and N‐iso‐propyl‐1,2‐diphenylethylamine (NPDPA): Metabolism and detectability in rat urine using GC‐MS,LC‐MSn and LC‐HR‐MS/MS

N‐Ethyl‐1,2‐diphenylethylamine (NEDPA) and N‐iso‐propyl‐1,2‐diphenylethylamine (NPDPA) are two designer drugs, which were confiscated in Germany in 2008. Lefetamine (N,N‐dimethyl‐1,2‐diphenylethylamine, also named L‐SPA), the pharmaceutical lead of these designer drugs, is a controlled substance in many countries. The aim of the present work was to study the phase I and phase II metabolism of these drugs in rats and to check for their detectability in urine using the authors’ standard urine screening approaches (SUSA). For the elucidation of the metabolism, rat urine samples were worked up with and without enzymatic cleavage, separated and analyzed by gas chromatography‐mass spectrometry (GC‐MS) and liquid chromatography‐high resolution‐tandem mass spectrometry (LC‐HR‐MS/MS). According to the identified metabolites, the following metabolic pathways for NEDPA and NPDPA could be proposed: N‐dealkylation, mono‐ and bis‐hydroxylation of the benzyl ring followed by methylation of one of the two hydroxy groups, combinations of these steps, hydroxylation of the phenyl ring after N‐dealkylation, glucuronidation and sulfation of all hydroxylated metabolites. Application of a 0.3 mg/kg BW dose of NEDPA or NPDPA, corresponding to a common lefetamine single dose, could be monitored in rat urine using the authors’ GC‐MS and LC‐MSⁿ SUSA. However, only the metabolites could be detected, namely N‐deethyl‐NEDPA, N‐deethyl‐hydroxy‐NEDPA, hydroxy‐NEDPA, and hydroxy‐methoxy‐NEDPA or N‐de‐iso‐propyl‐NPDPA, N‐de‐iso‐propyl‐hydroxy‐NPDPA, and hydroxy‐NPDPA. Assuming similar kinetics, an intake of these drugs should also be detectable in human urine. Copyright © 2014 John Wiley & Sons, Ltd.     

Studies on the in vivo contribution of human cytochrome P450s to the hepatic metabolism of glaucine,a new drug of abuse

Glaucine ((S)-5,6,6a,7-tetrahydro-1,2,9,10-tetramethoxy-6-methyl-4H-dibenzo [de,g]quinoline), main isoquinoline alkaloid of Glaucium flavum (Papaveraceae), is used as antitussive, but also as recreational drug of abuse. Glaucine was mainly metabolized by O- and N-demethylation to four isomers in rats. So far, only scarce pharmacokinetic data were available. Therefore, the aim of the presented study was to assess the involvement of the ten most important cytochrome P450 (P450) isoforms in the main metabolic steps and determination of their kinetic parameters using the metabolite formation approach. Reference standards of investigated metabolites were synthesized for quantification. In addition, the impact of isomeric standards was tested for calibration and the use of simple peak area ratios on the kinetic constants and resulting contribution of P450 isoforms on estimated hepatic clearance. Kinetic profiles of all metabolite formations followed classic Michaelis–Menten behavior. K_m values were between 25 and 140 μM, V_max between 0.10 and 1.92 pmol/min/pmol. Using the relative activity factor approach, the hepatic clearance was calculated to be 27 and 73% for 2-O-demethylation by CYP1A2 and CYP3A4, 82, 3, and 15% for 9-O-demethylation by CYP1A2, CYP2C19, and CYP2D6, and finally <1 and 99% for N-demethylation by CYP2D6 and CYP3A4. These data were confirmed by inhibition tests. The calibration mode for determination of the metabolite concentrations had no relevant impact on the estimation of in vivo hepatic clearance of glaucine. As glaucine was metabolized via three initial steps and different P450 isoforms were involved in the hepatic clearance of glaucine, a clinically relevant interaction with single inhibitors should not be expected.     

Actein and a fraction of black cohosh potentiate antiproliferative effects of chemotherapy agents on human breast cancer cells

The purpose of this study was to determine whether the triterpene glycosides present in black cohosh enhance the growth inhibitory effects of specific breast cancer chemotherapy agents. Black cohosh roots and rhizomes were extracted with methanol (MeOH)/water (H (2)O) and fractionated by solvent-solvent partitioning to yield three fractions: hexane, ethyl acetate (EtOAc) and water. The EtOAc fraction is enriched in triterpene glycosides, including the compound actein. Actein and the EtOAc fraction were then tested, alone and in combination with chemotherapy agents, for growth inhibition of the ER (-) Her2 overexpressing breast cancer cell line MDA-MB-453. We found that actein exerted a synergistic effect on growth inhibition when combined with doxorubicin or 5-flourouracil. Synergy was also obtained when the EtOAc fraction was combined with doxorubicin. Actein increased the percent of cells in the G1 phase of the cell cycle and had a similar effect when combined with 5-flourouracil or doxorubucin. Actein enhanced the induction of apoptosis by paclitaxel, 5-flourouracil or doxorubicin. Our results indicate that relatively low concentrations of actein or the EtOAc fraction of black cohosh can cause synergistic inhibition of human breast cancer cell proliferation when combined with different classes of chemotherapy agents.     

Aseptic meningitis associated with high dose intravenous immunoglobulin therapy.

Two cases of aseptic meningitis occurred in temporal association with high dose intravenous immunoglobulin therapy to treat thrombocytopenia. In neither case was any other aetiological agent identified and both patients completely recovered within a few days. This phenomenon has been reported in only one previous paediatric case.     

Mutation of the signal peptide-encoding region of the preproparathyroid hormone gene in familial isolated hypoparathyroidism.

Preproparathyroid hormone (preproPTH) gene mutation has been proposed as a cause of familial isolated hypoparathyroidism (FIH). We cloned the preproPTH alleles of a patient with autosomal dominant FIH and sequenced the coding regions, 5' flanking regions, and splice junctions. The putatively abnormal (based on previous linkage studies) allele differed from the other allele's normal sequence at only one nucleotide. This T to C point mutation changes the codon for position 18 of the 31 amino acid prepro sequence from cysteine to arginine, disrupting the hydrophobic core of the signal sequence. Because the hydrophobic core is required by secreted proteins for efficient translocation across the endoplasmic reticulum, the mutant protein is likely to be inefficiently processed. Indeed, in vitro studies demonstrated dramatically impaired processing of the mutant preproPTH to proPTH. In summary, we observed a point mutation in the signal peptide-encoding region of a preproPTH gene in one FIH kindred and demonstrated a functional defect caused by the mutation. Mutation of the signal sequence constitutes a novel pathophysiologic mechanism in man, and further study may yield important insights both into this form of hormone deficiency and into the role of signal sequences in human physiology.