Discovery of N-benzyl-6-methylpicolinamide as a potential scaffold for bleaching herbicides.

BACKGROUND: In pesticide research, bleaching herbicides have always been a hot topic. Our previous research showed that N-(4-fluorobenzyl)-2-methoxybenzamide is an innovative lead compound for bleaching herbicides. RESULTS: A total of 40 derivatives of picolinamides were prepared and evaluated for their herbicidal activity by Petri dish tests and postemergence trials. The structure-activity relationship (SAR) revealed that introducing electron-withdrawing groups at the 3- or 4-positions of the benzyl significantly enhances herbicidal activity. Furthermore, ZI-04 induced similar symptoms such as bleaching effect in treated weeds and accumulation of biosynthetic precursors for carotenoids as observed with diflufenican. ZI-04 also exhibited significant cross-resistance to diflufenican and had a lower resistance risk than diflufenican. CONCLUSION: N-benzyl-6-methylpicolinamides were discovered as a novel scaffold for bleaching herbicides. The accumulation of phytoene, phytofluene and ζ-Carotene in radish cotyledons, and cross-resistance observed with diflufenican, showed that title compounds can interfere with carotenoid biosynthesis. © 2024 Society of Chemical Industry.

An integrated approach to evaluate acetamiprid-induced oxidative damage to tRNA in human cells based on oxidized nucleotide and tRNA profiling.

Acetamiprid is poisonous to mammals due to severe acetamiprid-induced oxidative stress that could cause mitochondrial dysfunctions, lipid and protein oxidation, inflammation, apoptosis, and DNA damage. Evidence has accumulated for the role of oxidative stress in changing structures and functions of transfer RNAs (tRNAs) by inducing tRNA cleavage, reprogramming tRNA modifications and impairing aminoacyl-tRNA synthetase editing sites. However, the impact of acetamiprid-induced oxidative stress on tRNA is still unknown. Here, we investigated the effects of acetamiprid on cell viability, reactive oxygen species (ROS) levels, DNA damage, cellular oxidized nucleotide concentrations, and oxidative damage to tRNA in HepG2 cells and LO2 cells. Acetamiprid can cause the significant increment of ROS and DNA oxidative damage. In this study, an integrated approach was established to simultaneously study the network of oxidized nucleotides and explore the tRNA oxidative damage after acetamiprid exposure. A simple and high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method coupled with (trimethylsilyl)diazomethane (TMSD) derivatization was successfully developed to quantify 12 cellular oxidized nucleotides that cannot be detected using traditional detection methods because of the huge interferences from naturally abundant nucleotides. Meanwhile, the accumulation rate and the locating sites of 8-oxo-2, 7-dihydro-guanine (8-oxo-G) in tRNA were inspected using the established N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) labeling-based tRNA profiling method. After acetamiprid treatment, the increment of oxidized nucleoside triphosphates is smaller than that of their corresponding mono- and diphosphates, as well as the dephosphorylated nucleosides, on account of the existence of sanitization enzymes. Several tRNA fragments, CUC[m1A]Gp, CACGp, [Cm]C[m2G]p, and DDGp, are significantly downregulated in acetamiprid-treated HepG2 cells, while only [Cm]C[m2G]p in acetamiprid-treated LO2 cells. According to the profiling results, the significantly changed fragment CUC[m1A]Gp might be caused by the oxidation of guanine (G) to form 8-oxo-G at position 15 in human tRNAphe([Gm]AA), providing more information about the effect of oxidized nucleobases on tRNA's functions.

Hyperoside alleviates toxicity of ß-amyloid via endoplasmic reticulum-mitochondrial calcium signal transduction cascade in APP/PS1 double transgenic Alzheimer's disease mice.

Alzheimer's disease is a neurodegenerative disorder characterized by a decline in cognitive function. The ß-amyloid (Aß) hypothesis suggests that Aß peptides can spontaneously aggregate into ß-fragment-containing oligomers and protofibrils, and this activation of the amyloid pathway alters Ca2+ signaling in neurons, leading to neurotoxicity and thus apoptosis of neuronal cells. In our study, a blood-brain barrier crossing flavonol glycoside hyperoside was identified with anti-Aß aggregation, BACE inhibitory, and neuroprotective effect in cellular or APP/PSEN1 double transgenic Alzheimer's disease mice model. While our pharmacokinetic data confirmed that intranasal administration of hyperoside resulted in a higher bio-availability in mice brain, further in vivo studies revealed that it improved motor deficit, spatial memory and learning ability of APP/PSEN1 mice with reducing level of Aß plaques and GFAP in the cortex and hippocampus. Bioinformatics, computational docking and in vitro assay results suggested that hyperoside bind to Aß and interacted with ryanodine receptors, then regulated cellular apoptosis via endoplasmic reticulum-mitochondrial calcium (Ca2+) signaling pathway. Consistently, it was confirmed that hyperoside increased Bcl2, decreased Bax and cyto-c protein levels, and ameliorated neuronal cell death in both in vitro and in vivo model. By regulating Aß-induced cell death via regulation on Ca2+ signaling cascade and mitochondrial membrane potential, our study suggested that hyperoside may work as a potential therapeutic agent or preventive remedy for Alzheimer's disease.

Effect of retained embryos on pregnancy outcomes of in vitro fertilization: a matched retrospective cohort study.

OBJECTIVES: To explore the incidence of retained embryos (REs) in embryo transfer (ET) cycles and its effects on pregnancy outcomes in women undergoing in vitro fertilization (IVF). METHODS: This was a matched retrospective cohort study involving 29,160 ET cycles conducted from March 2016 to February 2021, in which ET cycles without RE were matched to the RE group at a 2:1 ratio. Clinical pregnancy, implantation, miscarriage, and live birth rates were compared between the with-RE and without-RE groups. RESULTS: Our study showed that the overall incidence of REs was 0.33% (95/29,160). There was a statistically significant difference in RE rate among the operators (P < 0.001), suggesting that the embryo retention rate may be affected by the individual operator. A total of 95 repeated ET cycles due to RE were included in the study group, and 190 ET cycles without RE were matched to the study group (1:2). There were no significant differences between the RE and matched groups in terms of implantation rate (35.6 vs. 38.0%; P = 0.608), clinical pregnancy rate (47.4 vs. 54.7%; P = 0.240), biochemical pregnancy rate (5.3 vs. 4.7%; P = 0.846), miscarriage rate (11.1 vs. 9.6%; P = 0.781), ectopic pregnancy rate (2.2 vs. 1.9%; P = 1.000) or live birth rate (41.1 vs. 48.9%; P = 0.208). CONCLUSIONS: The present findings demonstrated that immediate retransfer of REs did not significantly affect IVF outcomes, which may provide counselling information for patients when REs are identified and ET is reattempted. The incidence of REs was associated with the operator who expelled the embryos from the catheter. Attention to detail and frequent assessment of the operator's technique may facilitate avoidance of embryo retention.

Selective Chemical Labeling Strategy for Oligonucleotides Determination: A First Application to Full-Range Profiling of Transfer RNA Modifications.

To date, the extremely high polarity and poor signal intensity of macromolecular nucleic acids are greatly impeding the progress of mass spectrometry technology in the quality control of nucleic acid drugs and the characterization of DNA oxidation and RNA modifications. We recently described a general N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) labeling method for oligonucleotide determination and applied it to the full-range profiling of tRNA in vitro and in vivo studies for the first time. The primary advantages of this method include strong retention, no observable byproducts, predictable and easily interpreted MS2 data, and the circumvention of instrument harmful reagents that were necessary in previous methods. Selective labeling of N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide to the terminal phosphate groups of oligonucleotides endows it broadly applicable for DNA/RNA profiling. Moreover, the improvement of sequence coverage was achieved in yeast tRNAphe(GAA) analysis owing to this method's good detection capability of 1-12 nucleotides in length. We also extended this strategy to determine the abundance of modified bases and discover new modifications via digesting RNA into single-nucleotide products, promoting the comprehensive mapping of RNA. The easy availability of derivatization reagent and the simple, rapid one-step reaction render it easy to operate for researchers. When applied in characterizing tRNAs in HepG2 cells and rats with nonalcoholic fatty liver disease, a fragment of U[m1G][m2G], specific for tRNAAsn(QUU) in cells, was significantly upregulated, indicating a possible clue to nonalcoholic fatty liver disease pathogenesis.

Profiling Ribonucleotide and Deoxyribonucleotide Pools Perturbed by Remdesivir in Human Bronchial Epithelial Cells.

Remdesivir (RDV) has generated much anticipation for its moderate effect in treating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the unsatisfactory survival rates of hospitalized patients limit its application to the treatment of coronavirus disease 2019 (COVID-19). Therefore, improvement of antiviral efficacy of RDV is urgently needed. As a typical nucleotide analog, the activation of RDV to bioactive triphosphate will affect the biosynthesis of endogenous ribonucleotides (RNs) and deoxyribonucleotides (dRNs), which are essential to RNA and DNA replication in host cells. The imbalance of RN pools will inhibit virus replication as well. In order to investigate the effects of RDV on cellular nucleotide pools and on RNA transcription and DNA replication, cellular RNs and dRNs concentrations were measured by the liquid chromatography-mass spectrometry method, and the synthesis of RNA and DNA was monitored using click chemistry. The results showed that the IC50 values for BEAS-2B cells at exposure durations of 48 and 72 h were 25.3 ± 2.6 and 9.6 ± 0.7 µM, respectively. Ten (10) µM RDV caused BEAS-2B arrest at S-phase and significant suppression of RNA and DNA synthesis after treatment for 24 h. In addition, a general increase in the abundance of nucleotides and an increase of specific nucleotides more than 2 folds were observed. However, the variation of pyrimidine ribonucleotides was relatively slight or even absent, resulting in an obvious imbalance between purine and pyrimidine ribonucleotides. Interestingly, the very marked disequilibrium between cytidine triphosphate (CTP) and cytidine monophosphate might result from the inhibition of CTP synthase. Due to nucleotides which are also precursors for the synthesis of viral nucleic acids, the perturbation of nucleotide pools would block viral RNA replication. Considering the metabolic vulnerability of endogenous nucleotides, exacerbating the imbalance of nucleotide pools imparts great promise to enhance the efficacy of RDV, which possibly has special implications for treatment of COVID-19.

Rapid and sensitive determination of four bisphosphonates in rat plasma after MTBSTFA derivatization using liquid chromatography-mass spectrometry.

Bisphosphonates (BPs) have broad medical applications against osteoporosis, bone metastasis and Paget's disease. The BP-related jaw osteonecrosis limits their use extensively and has a causal relationship with the process of drug disposition, such as deposition on bone and slow elimination rate. Thus it is imperative to accurately determine BP levels in either clinical or pharmacological/toxicological studies. The ability of trimethylsilyl diazomethane (TMSD) to alkylate the hydroxyls in phosphoric groups is an advantage in terms of decreasing polarity and enhancing mass response of BPs. There are, however, practical limitations to the cumbersome sample preparation procedure, the prolonged reaction time, the by-products and the obstacle to ionization. To overcome these disadvantages, a simplified and rapid precolumn derivatization method with N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) to quantify etidronate, clodronate, alendronate and zoledronate BPs in rat plasma was established in this work. The derivatization reaction was conducted within 2 min at room temperature, and the unitary di-tert-butyldimethylsilyl (di-tBDMS) derivative was obtained for each BP. Derivatives were separated on a XTerra® MS C8 column (2.1 × 50 mm, 3.5 µm) with the mobile phase of 5 mM ammonium acetate buffer (pH 8.5) and acetonitrile, then detected using electrospray ionization tandem mass spectrometry in negative mode. An easy extraction process instead of the time-consuming solid-phase extraction (SPE) was employed for plasma treatment. The proposed method showed good linearity for BPs over the range of 2-500 ng/mL in 20 µL plasma and high sensitivity owing to the larger molecular ions, higher ionization capacity and more stable fragments of di-tBDMS derivatives. The intra- and inter-batch precision were <13.1 %, and the accuracy ranged within ±10 %. The extraction recovery varied from 75.4 to 88.0 %. The optimized method was successfully applied to characterize the pharmacokinetic profile of zoledronate in rats. Moreover, it is a promising approach for the determination of other phosphoric acid-containing metabolites.

Mitochondria-Mediated Pathogenesis and Therapeutics for Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) has become a worldwide epidemic over the last decade. Remarkable progress has been made in understanding the pathogenesis of NAFLD and, subsequently, in developing medications to treat this disease. Although the mechanisms of NAFLD are complex and multifactorial, accumulating and emerging evidence indicates that mitochondria play a critical role in the pathogenesis and progression of NAFLD. Pharmacologic therapies acting on mitochondria may therefore pave the way to novel strategies for the prevention and protection against NAFLD. This review focuses on new insights into the role of hepatic mitochondrial dysfunction in NAFLD, and summarizes recent studies on mitochondria-centric therapies for NAFLD utilizing new medications or repurposing of currently available drugs. Although some studies presented may feature controversial results or are still in lack of clinical verification, it is undoubted that medications that may spare the mitochondria from multiple levels of damage are highly promising, and have begun to be used with some degree of success.

Method for Quantification of Ribonucleotides and Deoxyribonucleotides in Human Cells Using (Trimethylsilyl)diazomethane Derivatization Followed by Liquid Chromatography-Tandem Mass Spectrometry.

Investigation into intracellular ribonucleotides (RNs) and deoxyribonucleotides (dRNs) is important for studies of the mechanism of many biological processes, such as RNA and DNA synthesis and DNA repair, as well as metabolic and therapeutic efficacy of nucleoside analogues. However, current methods are still unsatisfactory for determination of nucleotides in complex matrixes. Here we describe a novel method for the determination of RN and dRN pools in cells based on fast derivatization with (trimethylsilyl)diazomethane (TMSD) followed by quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Derivatization was accomplished in 3 min, and each derivatized nucleotide not only had a sufficient retention on reversed-phase column by introduction of methyl groups but also exhibited a unique ion transition which consequently eliminated mutual interference in LC-MS/MS. Chromatographic separation was performed on a C18 column with a simple acetonitrile-water gradient elution system, which avoided contamination and ion suppression caused by ion-pairing reagents. The developed method was fully validated and applied to the analysis of RNs and dRNs in cell samples. Moreover, results demonstrated that the applicability of this method could be extended to nucleoside analogues and their metabolites and could facilitate many applications in future studies.

Sandwich-Type Polyoxotungstate Consisting of Two Different Trilacunary Keggin-Type Units.

A unique mixed W/Sb/Mn/Ag sandwich-type metal-O cluster was isolated, in which the six-membered {Ag4O3[Mn(OH2)]2}2+ cationic belt is sandwiched between two different anionic slices: the trilacunary B-ß-[SbW9O33]9- and the central-atom-lost A-α-{[Mn(OH2)]2W7O32}18-.

[Comparison of minimally invasive extraction and traditional method in the extraction of impacted mandibular third molar].

PURPOSE: To compare minimally invasive extraction and traditional method in the extraction of impacted mandibular third molar. METHODS: One hundred and sixty patients with impacted mandibular third molar were equally divided into two groups. Patients in the experimental group were treated with minimally invasive extraction, using implant machine and luxator, while patients in the control group were treated with traditional methods including use of orthodox chisel. The operation time, intraoperative and postoperative complications including deformation of extraction sockets, dry socket, limitation of mouth opening, pain and swelling, and fear were observed and compared between the two groups. The data were analyzed with SPSS18.0 software package. RESULTS: The operation time was (17.32±1.01) min in the experimental group, significantly shorter than the control group which was (33.46±1.12）min (P<0.05); significant difference was found in the incidence of root fracture, medium or severe tooth sockets deformation and incidence of psychological fear during operation between the control group and experimental group(P<0.05); the degree of mouth opening after surgery, the incidence of moderate or severe pain after surgery was significantly lower in the experimental than in the control group(P<0.05). CONCLUSIONS: Minimally invasive extraction of mandibular impacted wisdom tooth is better than traditional method, with shorter operation time and less intraoperative and postoperative complications, which should be widely applied in clinic.

Relationship between HLA-G gene polymorphism and the susceptibility of esophageal cancer in Kazakh and Han nationality in Xinjiang.

OBJECTIVE: To explore the association between polymorphism of the human leukocyte antigen G (HLA-G) and susceptibility of esophageal carcinoma (EC) in Kazakh and Han nationality in Xinjiang. METHODS: The 14 bp deletion/insertion (rs16375) and 0105N (rs41557518) of HLA-G genotyping were determined by PCR and PCR-RFLP, respectively in 239 patients and 467 controls. RESULTS: There was a 2.69-fold (P(c) = 0.04, 95% CI: 1.30-5.55) increased risk of developing EC in individuals with the -14 bp/-14 bp genotype (rs16375) compared with those carrying +14 bp/+14 bp genotype in Kazakh after Bonferroni correction, there was no association of 0105N (rs41557518) both in Kazak and Han population. And there was a 2.82-fold (P(c) = 0.04, 95% CI: 1.32-6.04) increased risk of developing EC in individuals with -14 bp/-14 bp and C/C genotypes compared with those who had +14 bp/+14 bp and C/C genotypes in Kazakh. CONCLUSIONS: The study demonstrates that EC is associated with polymorphism of HLA-G14 bp in Chinese Kazak population. The 14 bp deletion/insertion of HLA-G gene may play a role in EC susceptibility of Kazakh.

Study on the relationship between TagSNPs and haplotype of hCHK2 and esophageal cancer in Kazakh and Han in Xinjiang.

AIM OF THE STUDY: To determine the association of hCHK2 rs2278022, rs2602431, and rs2970077 polymorphisms and haplotypes with susceptibility to esophageal cancer in Kazakh and Han in Xinjiang Uygur Autonomous Region. MATERIAL AND METHODS: Molecular epidemiology was carried out on 239 cases of esophageal cancer (132 Kazakh, 107 Han) and 513 controls (309 Kazakh, 204 Han) of Xinjiang. Polymorphisms of hCHK2 at rs2278022, rs2602431 and rs2970077 were analyzed by polymerase chain reaction-ligase detection reaction (PCR-LDR). Haplotypes were estimated by the SHEsis software. Statistical differences in genotype/haplotype frequencies, and frequencies between the case group and the control group were estimated. RESULTS: 1) No significant difference was observed in the frequency of hCHK2 at rs2278022, rs2602431 and rs2970077 between the cases and controls in Kazakh and Han (P > 0.05); 2) In Kazakh and Han, the distribution of haplotypes was not significantly different between esophageal cancer cases and controls (P > 0.05). CONCLUSIONS: Polymorphisms of hCHK2 at rs2278022, rs2602431 and rs2970077 and haplotypes are unlikely to be associated with the susceptibility to esophageal cancer in Kazakh and Han.

[Association between HLA-Cw polymorphism and inflammatory bowel disease].

OBJECTIVE: To investigate the association of HLA-Cw alleles with inflammatory bowel disease(IBD), so as to identify IBD susceptibility gene. METHODS: The HLA-Cw genotype were analyzed in 100 patients with ulcerative colitis (UC), 73 patients with Crohn's disease (CD) and 106 randomly ethnically matched healthy controls by sequence specific primer polymerase chain (PCR-SSP). RESULTS: HLA-Cw*07 gene phenotype frequencies increased in patients with UC (0.430) compared with that in healthy controls (0.226), P = 0.002; while HLA-Cw*12 gene phenotype frequencies increased in patients with CD (0.356) compared with that in healthy controls (0.123), P = 0.000. CONCLUSION: HLA-Cw*07 allele and HLA-Cw*12 allele may be strongly associated with the susceptibility of UC and CD, respectively.

[Relationship between expression of inhibitory killer cell immunoglobulin-like receptor HLA-Cw ligand and susceptibility to inflammatory bowel disease].

OBJECTIVE: To investigate the distribution of different phenotypes of inhibitory killer cell immunoglobulin-like receptor (iKIR) and its ligand HLA-Cw in patients with inflammatory bowel disease (IBD), and to explore whether iKIR/HLA-Cw combinations are associated with IBD susceptibility. METHODS: Peripheral blood samples were collected from 100 patients with ulcerative colitis (UC), 73 patients with Crohn's disease, and 106 randomly selected ethnically matched healthy controls. Polymerase chain reaction with sequence-specific primers was used to analyze the iKIR phenotypes, and the HLA-Cw phenotypes was examined with HLA-C LOCUS SSP UNITRAY kit, and the combination of HLA-Cw and its corresponding iKIR in individual was analyzed subsequently. RESULTS: The KIR2DL1 and KIR2DL3 gene phenotype frequencies in UC patients were 0.710 and 0.620 respectively, both significantly lower than those in healthy controls (0.896, chi(2) = 11.405 P = 0.001, and 0.821, chi(2) = 10.362 P = 0.001 respectively). The KIR2DL1 gene phenotype frequency in CD patients was 0.740, significantly lower than that in healthy controls (0.896, chi(2) = 7.589, P = 0.006). The KIR2DL1 HLA-C2 combination (2DL1(+)-HLA-C2(+)) in UC patients and CD patients were 0.380 and 0.411 respectively, both significantly lower than that in healthy controls (0.575, chi(2) = 7.876 P = 0.005 and 0.575, chi(2) = 4.681 P = 0.030 respectively). CONCLUSION: The susceptibility to IBD is associated with decreased KIR2DL1-HLA-C2 combination.

[Application of virtual reality technique in forensic pathology].

This article reviewed general information, application and progress of the virtual reality (VR) technique. Lectures showed that the VR technique would impact and prompt the teaching, experiment, research and application of forensic pathology with the development of operation guiding system, virtual autopsy, micro-imaging technique. Because of the limitation of software, hardware and the expense, the VR technique needed to be improved and perfected.