In vivo incorporation of fenfluramine and norfenfluramine into pigmented and nonpigmented hair of rats measured by HPLC-fluorescence detection

The incorporation profiles for fenfluramine (Fen) and its metabolite norfenfluramine (Norf) into black hair and white hair of Zucker rats and into white hair of Wistar rats after intraperitoneal (i.p.) administration of Fen or N-nitrosofenfluramine (N-Fen) were studied in great detail. The target compounds were determined by high-performance liquid chromatography with fluorescence detection using 4-(4,5-diphenyl-1 H-imidazol-2-yl)benzoyl chloride as a derivatization reagent. After repeated i.p. administration of Fen (5 mg/kg) for 4 days to Zucker rats, shaft and root samples of black and white hair were obtained 1 week after the first administration. It was surprising that Fen and Norf levels in root samples of white hair were much higher than those in shaft or root samples of black hair, strongly suggesting that unknown mechanisms other than the action of melanin take place in the white hair root. Time course profiles for Fen and Norf after administration of a single i.p. dose of Fen or N-Fen were constructed for Zucker and Wistar rats. The percent level of Fen or Norf in white hair was 15-50% of that in black hair at any interval within 600 min after a single administration of Fen in Zucker rats. Even with Wistar rats having only white hair, we could demonstrate the time courses for incorporation of Fen and Norf into white hair. Finally, time course profiles for Fen and Norf were also followed after a single i.p. administration of N-Fen; this experiment showed that the levels of Norf were much higher than those of Fen for both black and white hair samples of Zucker rats at any interval tested

High-Performance Liquid Chromatographic Analysis of Drugs of Abuse in Biologic Samples

Recently, drug abuse has become a serious social problem world wide. In Japan, methamphetamine (MP) is the most popular drug of abuse. In addition to MP, the use of 4,5-methylenedioxymethamphetamine (MDMA), called ecstacy, is rapidly increasing, especially among young people. The development of simple and convenient analytical methods for the analysis of these drugs of abuse is necessary for the prediction of and protection from human health risks. Many useful methods have been developed for qualification and quantification of drugs of abuse. Among these, gas chromatography with mass spectrometry (MS) and high-performance liquid chromatography with MS (HPLC-MS or LC-MS) or fluorescence (HPLC-FL) detection are widely used. As highly sensitive methods, precolumn or postcolumn derivatization methods are commonly utilized in HPLC. This review focuses on HPLC methods used for the practical analysis of drugs of abuse, mainly for amphetamine derivatives and MDMAs in biologic samples such as urine, blood, and hair

Recurrence of Stachybotrys chartarum during mycological and toxicological study of bioaerosols collected in a dairy cattle shed

Agricultural occupations associated with animal breeding and the processing of animal materials in confinement systems could potentially lead to bioaerosol exposures. Moulds and mycotoxins could be constituents of bioaerosols and should be studied because of their possible involvement in respiratory diseases and cancers. In order to characterize the fungal contamination of the indoor air in a dairy barn, bioaerosols were collected during 20 days in a cattle farm located in Normandy (France). Mycobiota, mycotoxins and the mutagenicity of bioaerosols were studied. The toxigenic ability of Aspergillus flavus group and Aspergillus fumigatus isolates was also evaluated in vitro. The prevalent airborne moulds were from the following potentially toxigenic species: Aspergillus flavus group, Aspergillus fumigatus, Penicillium chrysogenum, Stachybotrys chartarum, and the allergenic species Ulocladium chartarum, Cladosporium cladosporioides. In comparison with harvesting, grain handling or broiler breeding, the concentrations of viable moulds were lower in the cattle shed. Seasonal variations in levels of several species were also observed. This study revealed that aflatoxins were detected in bioaerosols and, for the first time, showed that farmers are possibly exposed to Stachybotrys chartarum during routine barn work. Moreover, the finding of mutagenicity from bioaerosols needs further investigations on bioaerosol composition

Spontaneous in Vitro and in Vivo Interaction of (-)-Oleocanthal with Glycine in Biological Fluids: Novel Pharmacokinetic Markers

Since the first discovery of its ibuprofen-like anti-inflammatory activity in 2005, the olive phenolic (-)-oleocanthal gained great scientific interest and popularity due to its reported health benefits. (-)-Oleocanthal is a monophenolic secoiridoid exclusively occurring in extra-virgin olive oil (EVOO). While several groups have investigated oleocanthal pharmacokinetics (PK) and disposition, none was able to detect oleocanthal in biological fluids or identify its PK profile that is essential for translational research studies. Besides, oleocanthal could not be detected following its addition to any fluid containing amino acids or proteins such as plasma or culture media, which could be attributed to its unique structure with two highly reactive aldehyde groups. Here, we demonstrate that oleocanthal spontaneously reacts with amino acids, with high preferential reactivity to glycine compared to other amino acids or proteins, affording two products: an unusual glycine derivative with a tetrahydropyridinium skeleton that is named oleoglycine, and our collective data supported the plausible formation of tyrosol acetate as the second product. Extensive studies were performed to validate and confirm oleocanthal reactivity, which were followed by PK disposition studies in mice, as well as cell culture transport studies to determine the ability of the formed derivatives to cross physiological barriers such as the blood-brain barrier. To the best of our knowledge, we are showing for the first time that (-)-oleocanthal is biochemically transformed to novel products in amino acids/glycine-containing fluids, which were successfully monitored in vitro and in vivo, creating a completely new perspective to understand the well-documented bioactivities of oleocanthal in humans. © 2021 American Chemical Society

Differences in amyloid-β clearance across mouse and human blood-brain barrier models: kinetic analysis and mechanistic modeling.

Alzheimer's disease (AD) has a characteristic hallmark of amyloid-β (Aβ) accumulation in the brain. This accumulation of Aβ has been related to its faulty cerebral clearance. Indeed, preclinical studies that used mice to investigate Aβ clearance showed that efflux across blood-brain barrier (BBB) and brain degradation mediate efficient Aβ clearance. However, the contribution of each process to Aβ clearance remains unclear. Moreover, it is still uncertain how species differences between mouse and human could affect Aβ clearance. Here, a modified form of the brain efflux index method was used to estimate the contribution of BBB and brain degradation to Aβ clearance from the brain of wild type mice. We estimated that 62% of intracerebrally injected 125I-Aβ40 is cleared across BBB while 38% is cleared by brain degradation. Furthermore, in vitro and in silico studies were performed to compare Aβ clearance between mouse and human BBB models. Kinetic studies for Aβ40 disposition in bEnd3 and hCMEC/D3 cells, representative in vitro mouse and human BBB models, respectively, demonstrated 30-fold higher rate of 125I-Aβ40 uptake and 15-fold higher rate of degradation by bEnd3 compared to hCMEC/D3 cells. Expression studies showed both cells to express different levels of P-glycoprotein and RAGE, while LRP1 levels were comparable. Finally, we established a mechanistic model, which could successfully predict cellular levels of 125I-Aβ40 and the rate of each process. Established mechanistic model suggested significantly higher rates of Aβ uptake and degradation in bEnd3 cells as rationale for the observed differences in 125I-Aβ40 disposition between mouse and human BBB models. In conclusion, current study demonstrates the important role of BBB in the clearance of Aβ from the brain. Moreover, it provides insight into the differences between mouse and human BBB with regards to Aβ clearance and offer, for the first time, a mathematical model that describes Aβ clearance across BBB