Differential effects of route of T‐2 toxin exposure on hepatic oxidative damage in mice

T‐2 toxin is the most toxic among mycotoxins and poses a potential health hazard for both humans and animals. At high doses, T‐2 toxin can cause shock‐like syndrome that can result in death. We evaluated the effect of time course and route of exposure on hepatic oxidative damage in mice and it is only such study so far to compare the effects of dermal and subcutaneous exposure of T‐2 toxin. Mice were exposed to 1 LD50 of T‐2 toxin either by percutaneous (5.94 mg/kg body weight) or subcutaneous (1.54 mg/kg body weight) route and sacrificed at 0, 1, 3, and 7 days postexposure. Analysis of a number of serum biochemical variables, antioxidant enzymes activity, gene and protein expression by immunoblot assay showed time and route dependent effects of T‐2 induced hepatic oxidative damage. Time dependent increase in protein carbonyl content and protein oxidation was seen in serum and liver. Results of our study may provide possible mechanism for developing medical countermeasures against T‐2 toxin. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 64–73, 2015.     

Comparative acute and combinative toxicity of aflatoxin B1 and T-2 toxin in animals and immortalized human cell lines

Aflatoxin B1 (AFB1) and T-2 toxin (T-2) are important food-borne mycotoxins that have been implicated in human health and as potential biochemical weapons threats. In this study the acute and combinative toxicity of AFB1 and T-2 were tested in F-344 rats, mosquitofish (Gambusia affinis), immortalized human hepatoma cells (HepG2) and human bronchial epithelial cells (BEAS-2B). Preliminary experiments were conducted in order to assess the acute toxicity and to obtain LD50, LC50 and IC50 values for individual toxins in each model, respectively. This was followed by testing combinations of AFB1 and T-2 to obtain LD50, LC50 and IC50 values for the combination in each model. All models demonstrated a significant dose response in the observed parameters to treatment. The potency of the mixture was gauged through the determination of the interaction index metric. The results of this study demonstrate that these two toxins interacted to produce alterations in the toxic responses generally classifiable as additive; however, a synergistic interaction was noted in the case of BEAS-2B. It can be gathered that this combination may pose a significant threat to public health and further research needs to be completed addressing alterations in metabolism and detoxification that may influence the toxic manifestations in combination.     

T‐2 toxin downregulates LHCGR expression,steroidogenesis, and cAMP level in human cumulus granulosa cells

Our goals were to investigate whether environmentally relevant doses of T‐2 toxin can affect human ovarian granulosa cells' function and to reveal the potential mechanism of T‐2 toxin's action. Results showed that T‐2 toxin strongly attenuated luteinizing hormone/choriogonadotropin receptor (LHCGR) mRNA expression in follicle‐stimulating hormone (FSH)‐stimulated human cumulus granulosa cells. Addition of human chorionic gonadotropin was not able to elicit maximal response of ovulatory genes amphiregulin, epiregulin, and progesterone receptor. T‐2 toxin reduced mRNA levels of CYP19A1 and steroidogenic acute regulatory protein (STAR) and lowered FSH‐stimulated estradiol and progesterone production. Mechanistic experiments demonstrated that T‐2 toxin decreased FSH‐stimulated cyclic adenosine monophosphate (cAMP) production. Addition of total PDE inhibitor 3‐isobutyl‐1‐methylxanthine prevented T‐2 toxin's action on LHCGR, STAR, and CYP19A1 mRNA expression in FSH‐stimulated human cumulus granulosa cells. Furthermore, T‐2 toxin partially decreased 8‐bromoadenosine 3′5′‐cyclic monophosphate (8‐Br‐cAMP)‐stimulated LHCGR and STAR, but did not affect 8‐Br‐cAMP‐stimulated CYP19A1 mRNA expression in human cumulus granulosa cells. Overall, our data indicate that environmentally relevant dose of T‐2 toxin decreases steroidogenesis and ovulatory potency in human cumulus granulosa cells probably through activation of PDE, thus posing a significant risk for female fertility.     

Comparative hepatotoxicity of deoxynivalenol in rat,mouse and human liver cells in culture

The present study was undertaken to assess, in vitro, the hepatotoxic potential of the food‐borne mycotoxin, deoxynivalenol (DON), using rat (Clone9 and MH1C1), mouse (NBL CL2) and human (WRL68 and HepG2) liver cells in culture. The cells were treated with DON for 24 h at 37 °C in 5% CO₂ at concentrations of 0–25 µg ml^?1. Following the treatment period, the cells were assayed for biochemical markers of hepatotoxicity that included three independent cytotoxicity assays, oxidative stress and mitochondrial dysfunction. Concentration‐dependent cytotoxicity of DON was observed in each of the five different liver cells derived from three different species (rat, mouse and human) over the entire concentration range studied, beginning at 0.1 µg ml^?1. At these concentrations DON did not induce a biologically significant increase in oxidative stress in these liver cells, and showed a significant decrease in the mitochondrial function only in the rat liver MH1C1 cells compared with the control. The results of this in vitro study suggest that DON is a potential hepatotoxin for the rat, mouse and human liver cells in the concentration range tested in this study. The liver cells used in this study showed distinct endpoint‐sensitivity to DON related to the species. Published in 2010 by John Wiley and Sons, Ltd.     

Synthesis of 2H‐ and 14C‐labeled fexinidazole and its primary metabolites labeled with 2H

The preparation of deuterium labeled fexinidazole, a 5‐nitroimidazole drug candidate for the treatment of Human African Trypanosomiasis, and its two main metabolites (fexinidazole sulfoxide and fexinidazole sulfone) for use as internal standards for liquid chromatography‐mass spectrometry are reported. Additionally, the synthesis of a ¹⁴ C‐labeled version of fexinidazole for absorption, distribution, metabolism, and excretion studies is also described via a five‐step procedure starting from commercially available potassium [¹⁴ C]cyanide. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of 2H‐ and 13C‐labelled sunitinib and its primary metabolite

Sunitinib (Sutent^®, Pfizer) was approved in 2006 for the treatment of gastrointestinal and renal cancer. Isotope‐labelled derivatives have already been prepared for PET and ADME radiography. The preparation of ¹³C‐ and ²H‐labelled internal standards of sunitinib (SU11248) and its primary metabolite (SU12662) for LC‐MS analysis of human blood samples is presented. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of the roles of dietary protein and calcium in fluoride‐induced changes in T‐lymphocyte subsets in rat

The roles of dietary protein (Pr) and calcium (Ca) levels on the changes in T‐lymphocyte subsets induced by excessive fluoride (F) intake were assessed using rats that were malnourished for 120 days as a model. The CD⁴⁺ and CD⁸⁺ T‐lymphocytes in the spleen tissue were determined by flow cytometry and immunofluorescence assay. The percentages of CD³⁺, CD⁴⁺, and CD⁸⁺ T‐lymphocytes were reduced in the spleen of rats exposed to excessive F, and malnutrition aggravated these changes in the T‐lymphocytes. In addition, the mRNA expression levels of IL‐1β, IL‐2, IL‐6, TNF‐α, and IFN‐γ in the spleen were downregulated significantly. We also reported herein the increased apoptosis ratio following caspase‐9 and caspase‐3 upregulation in the spleen of rats exposed to excessive amount of F. Light and transmisison electron microscopy revealed the irregularly arranged lymphocytes, few lymph nodules and the apoptotic characteristic of lymphocytes, which are caused by the increased expression of caspase. In addition, Pr and Ca supplementation reversed the morphologic and T‐lymphocytic changes in spleen under malnutrition. Taken together, our results revealed an endogenous caspase‐mediated mechanism of regulating the apoptosis of the T‐lymphocyte subsets, as well as the immune‐related cytokine secretion, which reduces the immune function in F‐induced rats. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1587–1595, 2017.     

Novel probes for imaging amyloid‐β: F‐18 and C‐11 labeling of 2‐(4‐aminostyryl)benzoxazole derivatives

2‐(4‐Methylaminostyryl)‐6‐(2‐[¹⁸F]fluoroethoxy)benzoxazole ([¹⁸F]BF‐168) was prepared and found to be a potential probe for imaging amyloid‐β. The precursor, a 6‐(2‐tosyloxyethoxy)benzoxazole derivative, was fluorinated with [¹⁸F]KF and Kryptofix 222 in acetonitrile, and the crude product purified by semi‐preparative HPLC to give [¹⁸F]BF‐168. The radiochemical purity was >95% and the maximum specific activity was 106 TBq/mmol at the end of synthesis. The synthesis time was 110 min from the end of bombardment. 2‐(4‐[N‐methyl‐¹¹C]methylaminostyryl)‐5‐fluorobenzoxazole ([¹¹C]BF‐145) was also prepared from 2‐(4‐aminostyryl)‐5‐fluorobenzoxazole, [¹¹C]MeI and 5 N NaOH in DMSO, and purified by semi‐preparative HPLC. The radiochemical purity was >95% and the specific activity was 40–70 TBq/mmol at the end of synthesis. The synthesis time was 45 min from the end of bombardment. Copyright © 2004 John Wiley & Sons, Ltd.     

13C‐ and 14C‐labelling of N‐[1‐(4‐chlorophenyl)‐1H‐pyrrol‐2‐yl‐methyleneamino] guanidinium acetate

N‐[1‐(4‐chlorophenyl)‐1H‐pyrrol‐2‐yl‐¹³C₄‐methyleneamino]guanidinium acetate has been synthesized by a four‐step procedure. This involved reduction of the Weinreb amide N,N′‐dimethyl‐N,N′‐dimethyloxybutane‐1,4‐diamide‐1,2,3,4‐¹³C₄ by Dibal‐H to give the corresponding unstable dialdehyde which is reacted in situ with 4‐chloroaniline to form 1‐(4‐chlorophenyl)‐1H‐pyrrole‐¹³C₄. This pyrrole analogue underwent a Vilsmeyer acylation with POCl₃/DMF followed by final reaction with aminoguanidine bicarbonate to produce the desired labelled compound with 99% atom ¹³C. By using DMF [α‐¹⁴C] a radio‐labelled analogue was synthesized with a specific activity of 60 mCi/mmol. Copyright © 2005 John Wiley & Sons, Ltd.     

T2毒素对大鼠红细胞膜脂流动性及脂质过氧化的影响

Ｔ２毒素对大鼠红细胞膜脂流动性及脂质过氧化的影响彭双清，杨进生（北京毒物药物研究所，北京１００８５０）Ｔ２毒素是倍半萜类两歧性分子，极易与膜发生作用［１］．它能抑制ＤＮＡ，ＲＮＡ和蛋白质的合成，引起ＤＮＡ单链断裂及多核蛋白体分裂，以及与巯基酶相结合［...     

T‐bet interferes with PD‐1/PD‐L1‐mediated suppression of CD4+ T cell inflammation and survival in Crohn's disease

Pathogenic inflammation mediated by overactive type 1 helper T cell (Th1) responses could exacerbate and perpetuate Crohn's disease. Programmed death (PD)‐1 and its ligand PD‐L1 pathway could be upregulated to suppress inflammation. We wondered why this pathway is ineffective at suppressing pathogenic Th1 inflammation in Crohn's disease patients. Here, we found that overexpression of T‐bet via transfection significantly reduced the expression of PD‐1. PD‐L1 was capable of suppression proinflammatory CD4⁺ T cells, but T‐bet transfection significantly reduced the susceptibility of CD4⁺ T cells toward PD‐L1‐mediated suppression, evidenced by the observations that at low PD‐L1 concentration T‐bet transfected and mock transfected CD4⁺ T cells presented comparable IL‐2 production, but at high PD‐L1 concentration, T‐bet transfected CD4⁺ T cells presented significantly higher IL‐2 than mock transfected CD4⁺ T cells. PD‐L1 could significantly reduce the survival of CD4⁺ T cells from Crohn's disease patients, but interestingly, in the absence of PD‐L1, the survival was better in mock transfected CD4⁺ T cells, while in the presence of PD‐L1, the survival was better in T‐bet transfected CD4⁺ T cells. Crohn's disease patients with greater severity presented higher T‐bet expression and lower PD‐1 expression in CD4⁺ T cells, demonstrating an association between T‐bet expression and disease progression. We also discovered that stimulation with bacterial antigens could upregulate the expression of T‐bet. Together, this study demonstrated that T‐bet overexpression could interfere with PD‐1/PD‐L1‐mediated suppression of CD4⁺ T cell inflammation and survival, and potentially contributed to the development and persistence of Crohn's disease.     

T2毒素对小鼠外周血象和骨髓造血干、祖细胞的作用

T2毒素2.3 mg/kg(相当LD_(30))单次ip后测定小鼠外周血象,BMNC及骨髓CFUs、CFU—GM、CFU—E和BFU—E的改变以了解T2毒素血液毒理的特征.外周血中WBC总数明显减少,RBC和pt无变化.T2毒素虽不影响CFUs的数量,但对CFU—GM、CFU—E和BFU—E均有杀伤作用,中毒后2 h三种细胞存活率达最低值分别为正常的27％、48％和57％,恢复速度甚快,5 d内全部正常.三种细胞的T2毒素剂量活存曲线均为指数坪型.分析了各类造血干细胞对T2毒素敏感性不同的原因可能与各种细胞固有特性和细胞增殖状态有关。     

Test purchase,identification and synthesis of 2‐amino‐1‐(4‐bromo‐2, 5‐dimethoxyphenyl)ethan‐1‐one (bk‐2C‐B)

2‐Amino‐1‐(4‐bromo‐2,5‐dimethoxyphenyl)ethan‐1‐one (bk‐2C‐B) has been recently offered for purchase by a variety of Internet retailers. This substance may be considered a cathinone analogue of the phenethylamine 2‐(4‐bromo‐2,5‐dimethoxyphenyl)ethan‐1‐amine (2C‐B) which suggests that it may have psychoactive effects in humans. A test purchase of bk‐2C‐B was carried out and its identity was confirmed by a range of analytical techniques including nuclear magnetic resonance spectroscopy, gas and liquid chromatography, and high‐resolution mass spectrometry. Confirmation was also obtained from the synthesis of bk‐2C‐B based on the implementation of the Delépine reaction in which the α‐brominated intermediate was reacted with hexamethylenetetramine to afford the primary amine. Analysis of underivatized bk‐2C‐B by gas chromatography–mass spectrometry (GC‐MS) showed that there was potential for artificial formation of 1‐(4‐bromo‐2,5‐dimethoxyphenyl)ethanone and a pyrazine dimer, these substances were not detected when employing liquid chromatographic analysis. Ion chromatography and X‐ray crystallography analysis confirmed that the purchased bk‐2C‐B consisted of a hydrochloride and hydrobromide salt mixture, which indicated that it might have been prepared by the hexamethylenetetramine route followed by hydrochloric acid hydrolysis of the quaternary ammonium salt. X‐ray crystallography also revealed that the purchased (mixed HCl/HBr salt) and synthesized bk‐2C‐B (HCl salt) exists as polymorphs. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of 2‐14C‐iminothiolane and 2‐13C,15N‐iminothiolane (Traut's reagent)

2‐Iminothiolane has found utility in the growing area of antibody–drug conjugates by serving as a lysine‐thiolating agent and the junction between the antibody and the cytotoxic payload during random conjugation of a monoclonal antibody. 2‐¹⁴C‐Iminothiolane was prepared from commercially available [¹⁴C]KCN using a four‐step sequence in an overall 10% radiochemical yield. Stable‐labeled 2‐¹³C,¹⁵N‐iminothiolane was also prepared from [¹³C¹⁵N]KCN in a similar manner. The^. labeled Traut's reagent produced by this sequence showed comparable reactivity as the commercially available unlabeled reagent with a representative monoclonal antibody and could serve as highly informative analytical tools to investigate antibody–drug conjugate formation via the random conjugation process.     

Synthesis of C‐14 and C‐13, H‐2‐labeled IKK inhibitor: [14C] and [13C4,D3]‐N‐(6‐chloro‐7‐methoxy‐9H‐pyrido[3,4‐b]indol‐8‐yl)‐2‐methyl‐3‐pyridinecarboxamide

[¹⁴C]‐N‐(6‐Chloro‐7‐methoxy‐9H‐pyrido [3,4‐b]indol‐8‐yl)‐2‐methyl‐3‐pyridinecarboxamide (5B ), an IKK inhibitor, was synthesized from [¹⁴C]‐barium carbonate in two steps in an overall radiochemical yield of 41%. The intermediate, [carboxyl‐¹⁴C]‐2‐methylnicotinic acid, was prepared by the lithiation and carbonation of 3‐bromo‐2‐methylpyridine. [¹³C₄,D₃]‐N‐(6‐chloro‐7‐methoxy‐9H‐pyrido [3,4‐b]indol‐8‐yl)‐2‐methyl‐3‐pyridinecarboxamide (5C ) was synthesized from [1,2,3,4‐¹³C₄]‐ethyl acetoacetate and [D₄]‐methanol in six steps in an overall yield of 2%. [¹³C₄]‐2‐methylnicotic acid, was prepared by condensation of [¹³C₄]‐ethyl 3‐aminocrotonate and acrolein, followed by hydrolysis with lithium hydroxide. Copyright © 2006 John Wiley & Sons, Ltd.     

Helioxanthin suppresses the cross talk of COX‐2/PGE2 and EGFR/ERK pathway to inhibit Arecoline‐induced Oral Cancer Cell (T28) proliferation and blocks tumor growth in xenografted nude mice

Helioxanthin, an active compound from Taiwania cryptomerioides Hayata, has been shown to have various biological activities. However, their anticancer effect in oral squamous cell carcinoma has not been well established yet. Helioxanthin inhibited the proliferation of oral squamous cell carcinoma cells in a dose‐dependent manner by inducing G2/M phase arrest. Similarly, helioxanthin inhibited cyclooxygenase‐2, (COX‐2), phosphorylated EGFR, and extracellular‐signal‐regulated kinases (ERK) protein level and further reduced the nuclear accumulation of phosphorylated epidermal growth factor receptor (pEGFR) and activator protein‐1(AP‐1) family protein, c‐fos. Moreover, helioxanthin at the dose of 20 and 30 mg kg^?1 for 15 days reduced the tumor growth in animal model. This study demonstrated that Helioxanthin exerts its anticancer activity against oral cancer cells by downregulating EGFR/ERK/c‐fos signaling pathway to inhibit COX‐2 level and by activating cyclin‐dependent kinase inhibitor (p27) to further induce G2/M cell cycle arrest. This helioxanthin may serve as a novel candidate for oral cancer prevention. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 2045–2056, 2016.     

Evaluation of renal markers of T1D in Sprague‐Dawley exposed to 2‐aminoanthracene

The incidence of type 1 diabetes (T1D) and its associated risks of chronic kidney disease or end‐stage renal disease development are on the rise. T1D is an autoimmune disease in which insulin‐producing beta cells are destroyed. Increased incidence of T1D has been suggested to be a result of environmental factors such as exposure to polycyclic aromatic hydrocarbons (PAHs). 2‐aminoanthracene (2AA) is a PAH that has been associated with the onset of early diabetic symptoms. This study was conducted to assess if 2AA dietary ingestion would induce T1D renal injuries. To accomplish study goals, Sprague‐Dawley rats were assigned into three 2AA dietary (0, 50, and 100 mg/kg‐2AA) ingestion groups for 12 weeks. Animals were evaluated for various morphometric indices, clinical markers, and gene expression. The rats in the 100 mg/kg group lost 5% less weight than the other treatment groups and converted roughly 3% more of their food intake into body mass. Renal histopathology indicated no significant difference between groups. The kidney weight per bodyweight of the 100 mg/kg treatment group was 30.1% greater than the control group. Creatinine concentration of the 100 mg/kg group was 46.2% greater than the control group. Serum glucose levels were significantly elevated in rats exposed to 2AA. On the contrary, serum albumin concentration was significantly reduced in 2AA‐treated rats. T1D and genetic markers of renal injury such as FABP1, SPP1, IL‐1B, and IL‐7 were elevated in treated groups. These results suggest that 2AA may induce the early diabetic renal injuries.     

Large‐scale preparation of 13C‐labeled 2‐(phenylthio)acetic acid and the corresponding labeled sulfoxides and sulfones

We have developed large‐scale efficient procedures for the conversion of commercially available [¹³C]‐ or [²H₃,¹³C]methanol and ¹³CO₂ or ¹³C‐labeled bromoacetic acid to 2‐(phenylthio)[1,2‐¹³C₂]‐, [1‐¹³C]‐, and [2‐¹³C]acetic acid. The resulting derivatives are versatile, chemically stable, and nonvolatile two‐carbon labeling precursors. We have used the ¹³C‐isotopomers of 2‐(phenylthio)acetic acid in the synthesis of ¹³C‐labeled acrylic acid, methacrylic acid, and trans‐crotonic acid.