Histone methylation-mediated microRNA-32-5p down-regulation in sensory neurons regulates pain behaviors via targeting Cav3.2 channels.

microRNA (miRNA)­mediated gene regulation has been studied as a therapeutic approach, but its functional regulatory mechanism in neuropathic pain is not well understood. Here, we identify that miRNA-32-5p (miR-32-5p) is a functional RNA in regulating trigeminal-mediated neuropathic pain. High-throughput sequencing and qPCR analysis showed that miR-32-5p was the most down-regulated miRNA in the injured trigeminal ganglion (TG) of rats. Intra-TG injection of miR-32-5p agomir or overexpression of miR-32-5p by lentiviral delivery in neurons of the injured TG attenuated established trigeminal neuropathic pain. miR-32-5p overexpression did not affect acute physiological pain, while miR-32-5p down-regulation in intact rats was sufficient to cause pain-related behaviors. Nerve injury increased the methylated histone occupancy of binding sites for the transcription factor glucocorticoid receptor in the miR-32-5p promoter region. Inhibition of the enzymes that catalyze H3K9me2 and H3K27me3 restored the expression of miR-32-5p and markedly attenuated pain behaviors. Further, miR-32-5p­targeted Cav3.2 T-type Ca2+ channels and decreased miR-32-5p associated with neuropathic pain caused an increase in Cav3.2 protein expression and T-type channel currents. Conversely, miR-32-5p overexpression in injured TG suppressed the increased expression of Cav3.2 and reversed mechanical allodynia. Together, we conclude that histone methylation-mediated miR-32-5p down-regulation in TG neurons regulates trigeminal neuropathic pain by targeting Cav3.2 channels.

Phosphine-Capped Effects Enable Full-Color Clusteroluminescence in Nonconjugated Polyesters.

Full-color luminophores have advanced applications in materials and engineering, but constructing color-tunable clusteroluminescence (CL) from nonconjugated polymers based on through-space interactions remains a huge challenge. Herein, we develop phosphine-capped nonconjugated polyesters exhibiting blue-to-red CL (400-700 nm) based on phosphine-initiated copolymerization of epoxides and cyclic anhydrides, especially P1-0.5TPP, which exhibits red CL (610 nm) with a high quantum yield of 32%. Experiments and theoretical calculations disclose that the phosphine-capped effect in polyesters brings about conformational changes and induces phosphine-ester clusters by through-space (n,π*) interactions. Moreover, CL colors and efficiencies can be easily tailored by types of phosphines, compositions and structures of polyesters, and concentration. Significantly, the role of polymer motions (group, segmental, and chain motions) on CL originating from microregions inside polyesters is revealed. Further, phosphine-capped nonconjugated polyesters are demonstrated to be nonconjugated dyes and fluorescent fibers and are also used for multicolor light-emitting diodes including white light. This work not only provides an engineering strategy based on the end-group effect to prepare full-color clusteroluminogens but also broadens the prospects for material applications.

Bioaccumulation and Male Reproductive Toxicity of the New Brominated Flame Retardant Tetrabromobisphenol A-Bis(2,3-dibromo-2-methylpropyl ether) in Comparison with Hexabromocyclododecane.

Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) (TBBPA-DBMPE) has come into use as an alternative to hexabromocyclododecane (HBCD), but it is unclear whether TBBPA-DBMPE has less hazard than HBCD. Here, we compared the bioaccumulation and male reproductive toxicity between TBBPA-DBMPE and HBCD in mice following long-term oral exposure after birth. We found that the concentrations of TBBPA-DBMPE in livers significantly increased with time, exhibiting a bioaccumulation potency not substantially different from HBCD. Lactational exposure to 1000 µg/kg/d TBBPA-DBMPE as well as 50 µg/kg/d HBCD inhibited testis development in suckling pups, and extended exposure up to adulthood resulted in significant molecular and cellular alterations in testes, with slighter effects of 50 µg/kg/d TBBPA-DBMPE. When exposure was extended to 8 month age, severe reproductive impairments including reduced sperm count, increased abnormal sperm, and subfertility occurred in all treated animals, although 50 µg/kg/d TBBPA-DBMPE exerted lower effects than 50 µg/kg/d HBCD. Altogether, all data led us to conclude that TBBPA-DBMPE exerted weaker male reproductive toxicity than HBCD at the same doses but exhibited bioaccumulation potential roughly equivalent to HBCD. Our study fills the data gap regarding the bioaccumulation and toxicity of TBBPA-DBMPE and raises concerns about its use as an alternative to HBCD.

Canagliflozin alleviates pulmonary hypertension by activating PPARγ and inhibiting its S225 phosphorylation.

Pulmonary hypertension (PH) is a progressive fatal disease with no cure. Canagliflozin (CANA), a novel medication for diabetes, has been found to have remarkable cardiovascular benefits. However, few studies have addressed the effect and pharmacological mechanism of CANA in the treatment of PH. Therefore, our study aimed to investigate the effect and pharmacological mechanism of CANA in treating PH. First, CANA suppressed increased pulmonary artery pressure, right ventricular hypertrophy, and vascular remodeling in both mouse and rat PH models. Network pharmacology, transcriptomics, and biological results suggested that CANA could ameliorate PH by suppressing excessive oxidative stress and pulmonary artery smooth muscle cell proliferation partially through the activation of PPARγ. Further studies demonstrated that CANA inhibited phosphorylation of PPARγ at Ser225 (a novel serine phosphorylation site in PPARγ), thereby promoting the nuclear translocation of PPARγ and increasing its ability to resist oxidative stress and proliferation. Taken together, our study not only highlighted the potential pharmacological effect of CANA on PH but also revealed that CANA-induced inhibition of PPARγ Ser225 phosphorylation increases its capacity to counteract oxidative stress and inhibits proliferation. These findings may stimulate further research and encourage future clinical trials exploring the therapeutic potential of CANA in PH treatment.

Identification and Fungicide Screening of Fungal Species Associated with Walnut Anthracnose in Shaanxi and Liaoning Provinces, China.

Walnut is cultivated around the world for its precious woody nut and edible oil. Recently, walnut infected by Colletotrichum spp. resulted in a great yield and quality loss. In August and September 2014, walnut fruits with anthracnose were sampled from two commercial orchards in Shaanxi and Liaoning provinces, and five representative isolates were used in this study. To identify the pathogen properly, four genes per region (internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase, actin, and chitin synthase) were sequenced and used in phylogenetic studies. Based on multilocus phylogenetic analysis, five isolates clustered with Colletotrichum fioriniae, including its ex-type, with 100% bootstrap support. The results of multilocus phylogenetic analyses, morphology, and pathogenicity confirmed that C. fioriniae was one of the walnut anthracnose pathogens in China. All 13 fungicides tested inhibited mycelial growth and spore germination. Flusilazole, fluazinam, prochloraz, and pyraclostrobin showed the strongest suppressive effects on the mycelial growth than the others, the average EC50 values ranged from 0.09 to 0.40 µg/ml, and there was not any significant difference (P < 0.05). Pyraclostrobin, thiram, and azoxystrobin were the most effective fungicides on spore germination (P < 0.05), and the EC50 values ranged from 0.01 to 0.44 µg/ml. Pyraclostrobin, azoxystrobin, fluazinam, flusilazole, mancozeb, thiram, and prochloraz exhibited a good control effect on walnut anthracnose caused by C. fioriniae, and preventive activities were greater than curative activities. Pyraclostrobin at 250 a.i. µg/ml and fluazinam at 500 a.i. µg/ml provided the highest preventive and curative efficacy, and the values ranged from 81.3 to 82.2% and from 72.9 to 73.6%, respectively. As a consequence, mancozeb and thiram could be used at the preinfection stage, and pyraclostrobin, azoxystrobin, flusilazole, fluazinam, and prochloraz could be used at the early stage for effective prevention and control of walnut anthracnose caused by C. fioriniae. The results will provide more significant instructions for controlling the disease effectively in northern China.

Interpreting the chemical changes and therapeutic effect of Coptidis Rhizoma against ulcerative colitis before and after processing based on mathematical statistics and network pharmacology.

INTRODUCTION: Coptidis Rhizoma (CR) is one of the most frequently used herbs to treat ulcerative colitis (UC) and is often processed before usage. However, the composition changes and therapeutic effects of CR before and after processing in the treatment of UC are still unclear. OBJECTIVE: The purpose of the study is to explore the chemical components and therapeutic effects of crude and processed CR. MATERIAL AND METHODS: CR was processed according to the 2020 version of the Chinese Pharmacopoeia. The liquid chromatography-mass spectrometry (LC-MS) and multivariate statistical analysis were used to screen the different compounds before and after processing. The network pharmacological prediction was carried out. The mechanism and therapeutic effects between crude and processed CR were verified by using dextran sulphate sodium-induced UC mice assay. RESULTS: Ten compounds distinguish crude and processed CR based on multivariate statistical analysis. Network pharmacology predicts that the 10 compounds mainly play a role through TNF-α and IL-6 targets and PI3K/Akt and HIF-1 signalling pathways, and these results are verified by molecular biology experiments. For IL-6, IL-10 and TNF-α inflammatory factors, CR is not effective, while CR stir-fried with Evodiae Fructus (CRFE) and ginger juice (CRGJ) are. For PI3K/p-Akt, Cleaved caspase3, NF- κBp65 and HIF-1α signalling pathways, CR has therapeutic effects, while CRFE and CRGJ are significant. CONCLUSION: Overall, CRFE and CRGJ show better effects in treating UC. The chemical changes of processing and the efficacy of processed CR are correlated, which provides a scientific basis for the clinical use of crude and processed CR.

Cervical carcinogenesis risk association of HPV33 E6 and E7 genetic variations in Taizhou, Southeast China.

BACKGROUND: Human papillomavirus (HPV) 33 belongs to the Alphapapillomavirus 9 (α-9 HPV) species group, which also contains types 16, 31, 35, 52, 58 and 67. The purpose of this study was to investigate the genetic variations of HPV33 and to explore its carcinogenicity among women in Taizhou, Southeast China. METHODS: Exfoliated cervical cells were collected for HPV genotyping. Only single HPV33 infection cases were selected, and their E6 and E7 genes were sequenced using the ABI 3730xl sequencer and then analysed using MEGA X. RESULTS: From 2014 to 2020, a total of 185 single HPV33-positive specimens were successfully amplified. We obtained 15 distinct HPV33 E6/E7 variants, which were published in GenBank under accession numbers OQ672665-OQ672679. Phylogenetic analysis revealed that all HPV33 E6/E7 variants belonged to lineage A, of which 75.7% belonged to lineage A1. Compared with CIN1, the proportion of sublineage A1 in CIN2/3 was higher, but there was no significant difference (76.5% vs. 80.6%, P > 0.05). Altogether, 20 single nucleotide substitutions were identified, of which 6 were novel substitutions, including T196G (C30G), A447T, G458T (R117L), G531A, A704A, and C740T. In addition, no significant trends were observed between the nucleotide substitutions of HPV33 E6/E7 variants and the risk of cervical lesions. CONCLUSION: This study provides the most comprehensive data on genetic variations, phylogenetics and carcinogenicity of HPV33 E6/E7 variants in Southeast China to date. The data confirmed that cervical lesions among women in Taizhou are attributable to HPV33, which may be due to the high infection rate of sublineage A1 in the population.

Pristane cadmium chloride nanoemulsion accelerates the onset of systemic lupus erythematosus in a C57BL/6 mouse model.

OBJECTIVE: To accelerate the onset of systemic lupus erythematosus in C57BL/6 mice by injecting cadmium chloride nanoemulsion and shorten the traditional modeling time. METHODS: Pristane cadmium chloride nanoemulsion was prepared, and 66 C57BL/6 mice were randomly divided into four groups. The pristane group was intraperitoneally injected with 0.6 mL of pristane blank nanoemulsion, the model group was injected with 0.6 mL of pristane cadmium chloride nanoemulsion, the Cadmium chloride control group was injected with 0.6 mL of cadmium chloride nanoemulsion, and the control group was injected with the same amount of 0.9% sodium chloride solution. Urine protein content, anti-dsDNA antibody content, Th1 cell/Th2 cell ratio, and kidney staining were detected in each group. RESULTS: The model group began to develop disease in the 4th week, the anti-dsDNA antibody level reached 566.71 ± 1.44 ng/L, and the proteinuria reached 245.38 ± 30.54 ng/mL. The model group showed an onset at least 5 weeks earlier than that in the pristane group. There was no significant difference in anti-dsDNA antibody content between Cadmium chloride control group and blank group. At the 12th week, the Th1/Th2 cell ratio in the model group significantly decreased, and the pathological changes in the kidneys were consistent with the typical manifestations of lupus in mouse models. CONCLUSION: These results suggest that cadmium chloride promotes earlier onset of pristane-induced systemic lupus erythematosus in a C57BL/6 mouse model.

Retinoic acid inhibits the pyroptosis of degenerated nucleus pulposus cells by activating Sirt1-SOD2 signaling.

AIM: Intervertebral disc (IVD) degeneration is a common disease initiated by the degeneration of the nucleus pulposus (NP). The pyroptosis of degenerated NP cells (dNPCs) plays an important role in NP degeneration. The purpose of this study is to identify a feasible solution that can inhibit NP cell pyroptosis to therapy the degeneration of the intervertebral disc. METHODS: Cell viability and proliferation were quantified by Cell Counting Kit-8 assay. The measurement of cellular reactive oxygen species (ROS) was detected by 2,7-Dichlorodi-hydrofluorescein diacetate. The death of cells was analyzed by the Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick-End Labeling (TUNEL) method of fluorescence analysis. The pyroptosis of cells was assessed by flow cytometry analyses. The contents of sulfate glycosaminoglycans were detected by a blyscan assay kit. RESULT: In this study, we determined the effects of retinoic acid (RA) on dNPCs and investigated the underlying mechanism of RA-mediated pyroptosis in dNPCs. We also verified the effects of RA on IVD degeneration in vivo. Our results demonstrated that RA significantly increased the proliferation and the protein expression of sox9, aggrecan, and collagen II of dNPCs. Pyroptosis-related proteins and the pyroptosis rate of dNPCs were significantly decreased by RA. We found that Sirt1-SOD2 signaling was activated, while ROS generation and TXNIP/NLRP3 signaling in dNPCs were inhibited after the addition of RA. Furthermore, RA also recovered the structure of NP and increased the contents of sulfated glycosaminoglycans and collagen in vivo. CONCLUSION: Our study demonstrated that RA could inhibit the pyroptosis and increase the extracellular matrix synthesis function of dNPCs and verified that RA has a protective effect on IVD degeneration.

Visible-Light-Mediated Annulation/Thiolation of 2-Isocyanobiaryls with Disulfides to Organoylthiophenanthridines Derivatives.

A visible-light-induced annulation/thiolation of 2-isocyanobiaryls with dialkyl(aryl)disulfides has been established, delivering a sustainable and atom-economic route to 6-organoylthiophenanthridines with wild functional group tolerance and good to excellent yields under oxidant-, base-, and transition-metal-free conditions.

Extended exposure to tetrabromobisphenol A-bis(2,3-dibromopropyl ether) leads to subfertility in male mice at the late reproductive age.

Tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), a commonly used brominated flame retardant as a decabromodiphenyl ether substitute, has been detected in various environmental compartments, but its health hazards remain largely unknown. Our recent study showed that low-dose exposure of male mice to TBBPA-BDBPE from postnatal day (PND) 0 to 56 caused remarkable damage to the microtubule skeleton in Sertoli cells and the blood-testis barrier (BTB) but exerted little effect on conventional reproductive endpoints in adulthood. To investigate whether TBBPA-BDBPE may cause severe reproductive impairments at late reproductive age, here, we extended exposure of historically administrated male mice to 8-month age and allowed them to mate with non-treated females for the evaluation of fertility, followed by a general examination for the reproductive system. As expected, we found that 8-month exposure to 50 µg/kg/d as well as 1000 µg/kg/d TBBPA-BDBPE caused severe damage to the reproductive system, including reduced sperm counts, increased sperm abnormality, histological alterations of testes. Moreover, microtubule damage and BTB-related impairment were still observed following 8-month exposure. Noticeably, high-dose TBBPA-BDBPE-treated mice had fewer offspring with a female-biased sex ratio. All results show that long-term exposure to TBBPA-BDBPE caused severe reproductive impairment, including poor fertility at late reproductive age. It is therefore concluded that slight testicular injuries in early life can contribute to reproductive impairment at late reproductive age, highlighting that alterations in certain non-conventional endpoints should be noticed as well as conventional endpoints in future reproductive toxicity studies.

Hyperactivity of Purkinje cell and motor deficits in C9orf72 knockout mice.

A hexanucleotide (GGGGCC) repeat expansion in the first intron of the C9ORF72 gene is the most frequently reported genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The cerebellum has not traditionally been thought to be involved in the pathogenesis of C9ORF72-associated ALS/FTD, but recent evidence suggested a potential role. C9ORF72 is highly expressed in the cerebellum. Decreased C9ORF72 transcript and protein levels were detected in the postmortem cerebellum, suggesting a loss-of-function effect of C9ORF72 mutation. This study investigated the role of loss of C9ORF72 function using a C9orf72 knockout mouse line. C9orf72 deficiency led to motor impairment in rotarod, beam-walking, paw-print, open-field, and grip-strength tests. Purkinje cells are the sole output neurons in the cerebellum, and we next determined their involvement in the motor phenotypes. We found hyperactivity of Purkinje cells in the C9orf72 knockout mouse accompanied by a significant increase of the large-conductance calcium-activated potassium channel (BK) protein in the cerebellum. The link between BK and Purkinje cell firing was demonstrated by the acute application of the BK activator that increased the firing frequency of the Purkinje cells ex vivo. In vivo chemogenetic activation of Purkinje cells in wild-type mice led to similar motor deficits in rotarod and beam-walking tests. Our results highlight that C9ORF72 loss alters the activity of the Purkinje cell and potentially the pathogenesis of the disease. Manipulating the Purkinje cell firing or cerebellar output may contribute to C9ORF72-associated ALS/FTD treatment.

Cobalt-Catalyzed Regiodivergent Double Hydrosilylation of Arylacetylenes.

Double hydrosilylation of alkynes represents a straightforward method to synthesize bis(silane)s, yet it is challenging if α-substituted vinylsilanes act as the intermediates. Here, a cobalt-catalyzed regiodivergent double hydrosilylation of arylacetylenes is reported for the first time involving this challenge, accessing both vicinal and geminal bis(silane)s with exclusive regioselectivity. Various novel bis(silane)s containing Si-H bonds can be easily obtained. The gram-scale reactions could be performed smoothly. Preliminarily mechanistic studies demonstrated that the reactions were initiated by cobalt-catalyzed α-hydrosilylation of alkynes, followed by cobalt-catalyzed ß-hydrosilylation of the α-vinylsilanes to deliver vicinal bis(silane)s, or hydride-catalyzed α-hydrosilylation to give geminal ones. Notably, these bis(silane)s can be used for the synthesis of high-refractive-index polymers (nd up to 1.83), demonstrating great potential utility in optical materials.

NIR Clusteroluminescence of Non-conjugated Phenolic Resins Enabled by Through-Space Interactions.

Clusteroluminescence (CL) and through-space interactions (TSIs) of non-conjugated molecules have drawn more attention due to their unique photophysical behaviors that are different from largely conjugated luminogens. However, achieving red and even near-infrared (NIR) emission from such systems is still challenging due to the intrinsic drawbacks of non-conjugated molecules and the lack of theories for structure-property relationships. In this work, six phenolic resins are designed and synthesized based on two molecule-engineering strategies: increasing the number of TSIs units and introducing electron-donating/-withdrawing groups. All phenolic resins are verified as luminogens with CL property (CLgens), and the first example of CLgens with NIR emission (maximum emission wavelength ≥680 nm) and high absolute quantum yield (47 %) is reported. Experiments and theoretical analysis reveal that two TSIs types, through-space locally excited state and through-space charge transfer state, play essential roles in achieving CL from these non-conjugated polymers, which could be manipulated via changing structural conformation and electron density or altering electron transition behaviors. This work not only provides an approach to manipulate TSIs and CL of non-conjugated polymers but also endows commercially available phenolic resins with high practical value as luminescence materials.

Aliphatic Polyesters with White-Light Clusteroluminescence.

Single-molecule white-light emission (SMWLE) has many advantages in practical applications; however, the fabrication of SMWLE from nonconjugated luminescent polymers, namely, clusteroluminogens (CLgens), is still a big challenge. Herein, the first example of linear nonconjugated polyesters with SMWLE is reported. Twenty-four kinds of nonconjugated aliphatic polyesters with tunable clusteroluminescence (CL) colors and efficiency were synthesized by the copolymerization of six epoxides and four anhydrides. Experimental and calculation results prove that, at the primary structure level, the balance of structural flexibility and rigidity via adjusting the side-chain length significantly enhances the efficiency of CL without wavelength change. However, altering the chemical structures of the monomer from succinic anhydride to trans-maleic anhydride (MA), cis-MA, and citraconic anhydride (CA), secondary structures of these polyesters change from helix to straight and folding sheet accompanied by gradually red-shifted CL from 460 to 570 nm due to the increase in through-space n-π* interactions, as demonstrated by the computational and experimental results. Then, pure SMWLE with CIE coordination (0.30, 0.32) based on overlapped short-wavelength and long-wavelength CL is achieved in CA-based polyesters. This work not only provides further insights into the emission mechanism of CL but also provides a new strategy to manipulate the properties of CL by regulating the hierarchical structures of CLgens.

Genetic variability in the E6 and E7 oncogenes of HPV52 and its prevalence in the Taizhou area, China.

BACKGROUND: Human papillomavirus (HPV) 52 is one of the prevalent oncogenic HPV genotypes in East Asia. Chinese women have the highest susceptibility to the HPV52 type, but research data on HPV52 genetic variability and its carcinogenicity in China is lacking. METHODS: The present study aimed to investigate the genetic variability of HPV52 currently circulating among Chinese women by PCR sequencing the entire E6 and E7 oncogenes. HPV52 sequence alignment, genetic heterogeneity analyses and maximum-likelihood phylogenetic tree construction were performed by BioEdit software and MEGA X software. RESULTS: Between 2016 and 2018, the overall HPV infection rate was 21.3%, of which HPV52 was the most prevalent high-risk type (17.2%) in the Taizhou area, China. A total of 339 single HPV52-positive samples were included in this study. We obtained 27 distinct variation patterns of HPV52 with the accession GenBank numbers ON529577-ON529603. Phylogenetic analysis showed that 96.6% of HPV52 variants belonged to lineage B, which seemed to be uniquely defined by G350T, A379G (K93R) in the E6 gene and C751T, A801G in the E7 gene. Due to the dominance of lineage B in our study population, the results could not be used to assess the association of the HPV52 (sub)lineage with the risk of cervical lesions. In addition, no significant trends were observed between the nucleotide substitutions of HPV52 variants and the risk of cervical carcinogenesis. CONCLUSION: Our data showed that HPV52 variants were strongly biased towards lineage B. These results confirmed that cervical lesions in the Taizhou area are highly attributable to HPV52, which may be due to the high infection rate of lineage B in the population.

Study on the metabolism profile of flavanomarein in Coreopsis tinctoria Nutt.

Coreopsis tinctoria Nutt. (family Asteraceae) is a popular medicine-food plant, which improves chronic diseases such as hyperlipemia, hypertension, and diabetes. Flavanomarein is the main active component of Coreopsis tinctoria Nutt, in which the blood concentration of volunteers is low and bioavailability is poor. Thus, the understanding of flavanomarein metabolites and metabolic pathways is significant to clarify its effectiveness. This study systematically studied the metabolites of flavanomarein by oral and injection. The biological samples (feces, urine, and plasma) were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in negative ion mode. The metabolic law of flavanomarein in the liver was further verified by a liver microsomal incubation experiment in vitro. A total of 12 metabolites were identified by oral administration while 15 metabolites were detected by injection. It was shown that metabolic pathways include acetylation, hydroxylation, glucuronidation, methylation, dehydrogenation, and so forth. The liver extraction rate of flavanomarein was 0.08, which means the metabolic stability of flavanomarein is well in rats' liver microsomes. It is a systematic study on the metabolism of flavanomarein and provides a metabolic rationale for further in-depth in vivo biotransformation.

Interactions of Nereistoxin and Its Analogs with Vertebrate Nicotinic Acetylcholine Receptors and Molluscan ACh Binding Proteins.

Nereistoxin (NTX) is a marine toxin isolated from an annelid worm that lives along the coasts of Japan. Its insecticidal properties were discovered decades ago and this stimulated the development of a variety of insecticides such as Cartap that are readily transformed into NTX. One unusual feature of NTX is that it is a small cyclic molecule that contains a disulfide bond. In spite of its size, it acts as an antagonist at insect and mammalian nicotinic acetylcholine receptors (nAChRs). The functional importance of the disulfide bond was assessed by determining the effects of inserting a methylene group between the two sulfur atoms, creating dimethylaminodithiane (DMA-DT). We also assessed the effect of methylating the NTX and DMA-DT dimethylamino groups on binding to three vertebrate nAChRs. Radioligand receptor binding experiments were carried out using washed membranes from rat brain and fish (Torpedo) electric organ; [3H]-cytisine displacement was used to assess binding to the predominantly high affinity alpha4beta2 nAChRs and [125I]-alpha-bungarotoxin displacement was used to measure binding of NTX and analogs to the alpha7 and skeletal muscle type nAChRs. While the two quaternary nitrogen analogs, relative to their respective tertiary amines, displayed lower α4ß2 nAChR binding affinities, both displayed much higher affinities for the Torpedo muscle nAChR and rat alpha7 brain receptors than their respective tertiary amine forms. The binding affinities of DMA-DT for the three nAChRs were lower than those of NTX and MeNTX. An AChBP mutant lacking the C loop disulfide bond that would potentially react with the NTX disulfide bond displayed an NTX affinity very similar to the parent AChBP. Inhibition of [3H]-epibatidine binding to the AChBPs was not affected by exposure to NTX or MeNTX for up to 24 hr prior to addition of the radioligand. Thus, the disulfide bond of NTX is not required to react with the vicinal disulfide in the AChBP C loop for inhibition of [3H]-epibatidine binding. However, a reversible disulfide interchange reaction of NTX with nAChRs might still occur, especially under reducing conditions. Labeled MeNTX, because it can be readily prepared with high specific radioactivity and possesses relatively high affinity for the nAChR-rich Torpedo nAChR, would be a useful probe to detect and identify any nereistoxin adducts.

Comparison of Dechlorane Plus Concentrations in Sequential Blood Samples of Pregnant Women in Taizhou, China.

To develop an appropriate sampling strategy to assess the intrauterine exposure to dechlorane plus (DP), we investigated DP levels in sequential maternal blood samples collected in three trimesters of pregnancy, respectively, from women living in Taizhou. The median concentration of DPs (sum of syn-DP and anti-DP) in all samples was 30.5 pg g−1 wet-weight and 5.01 ng g−1 lipid-adjusted weight, respectively. The trimester-related DP concentrations were consistently strongly correlated (p < 0.01), indicating that a single measurement of DP levels could represent intrauterine exposure without sampling from the same female repeatedly; however, the wet-weight levels significantly increased across trimesters (p < 0.05), while the lipid-adjusted levels did not significantly vary. Notably, whether lipid-adjusted weight or wet-weight levels, the variation extent of DP across trimesters was found to be less than 41%, and those for other persistent organic pollutants (POPs) reported in the literature were also limited to 100%. The limitation in variation extents indicated that, regardless of the time of blood collection during pregnancy and how the levels were expressed, a single measurement could be extended to screen for exposure risk if necessary. Our study provides different strategies for sampling the maternal blood to serve the requirement for assessment of in utero exposure to DP.

A survey of the awareness and knowledge of oral cancer among residents in Beijing.

BACKGROUND: The present study aimed to investigate oral cancer awareness and its related knowledge among residents in Beijing. METHODS: A questionnaire survey was conducted among Beijing residents concerning their knowledge of oral cancer, and its prevention and treatment. RESULTS: A total of 3055 questionnaires were completed, 45.8% by males and 54.2% by females. The ages of the respondents ranged from 15 to 93 years; 12.4% were smokers, 1.1% chewed betel nuts, and 82.5% brushed their teeth at least twice a day. Lung cancer was heard of by the most respondents, followed by gastric cancer and liver cancer; oral cancer was the least heard of. More than 60% of respondents were unaware of the risk factors and early signs of oral cancer. CONCLUSIONS: This survey demonstrated a general lack of public awareness and knowledge about oral cancer. Specific measures should be taken to improve public awareness of oral cancer and its prevention and treatment.