Reaction sites of pyrimidine bases and nucleosides during chlorination: A computational study.

As important components of soluble microbial products in water, nucleobases have attracted much attention due to the high toxicity of their direct aromatic halogenated disinfection by-products (AH-DBPs) during chlorination. However, multiple halogenation sites of AH-DBPs pose challenges to identify them. In this study, reaction sites of pyrimidine bases and nucleosides during chlorination were investigated by quantum chemical computational method. The results indicate that the anion salt forms play key roles in chlorination of uracil, thymine, and their nucleosides, while neutral forms make predominant contributions to cytosine and cytidine. In view of both kinetics and thermodynamics, C5 is the most reactive site for uracil and thymine, N3/C5 and N3 for respective uridine and thymidine, N1/C5/N4 and N4 for respective cytosine and cytidine, whose estimated apparent rate constants kobs-est of ∼103, 103/102, 106/102/104, and 103 M-1 s-1, respectively, in consistent with the known experimental results. C6 in all pyrimidine compounds is hardly attacked by Cl+ in HOCl ascribed to its positive charge, but readily attacked by OH‾ in hydrolysis and the N1=C6 bond was found to possess the highest reactivity in hydrolysis among all double bonds. In addition, the structure-kinetic reactivity relationship study reveals a relatively strong correlation between lgkobs-est and APT charge in all pyrimidine compounds rather than FED2 (HOMO). The results are helpful to further understand the reactivity of various reaction sites in aromatic compounds during chlorination.

Identification of reaction sites and chlorinated products of purine bases and nucleosides during chlorination: a computational study.

Hypochlorous acid (HOCl) released from activated leukocytes plays a significant role in the human immune system, but is also implicated in numerous diseases due to its inappropriate production. Chlorinated nucleobases induce genetic changes that potentially enable and stimulate carcinogenesis, and thus have attracted considerable attention. However, their multiple halogenation sites pose challenges to identify them. As a good complement to experiments, quantum chemical computation was used to uncover chlorination sites and chlorinated products in this study. The results indicate that anion salt forms of all purine compounds play significant roles in chlorination except for adenosine. The kinetic reactivity order of all reaction sites in terms of the estimated apparent rate constant kobs-est (in M-1 s-1) is heterocyclic NH/N (102-107) > exocyclic NH2 (10-2-10) > heterocyclic C8 (10-5-10-1), but the order is reversed for thermodynamics. Combining kinetics and thermodynamics, the numerical simulation results show that N9 is the most reactive site for purine bases to form the main initial chlorinated product, while for purine nucleosides N1 and exocyclic N2/N6 are the most reactive sites to produce the main products controlled by kinetics and thermodynamics, respectively, and C8 is a possible site to generate the minor product. The formation mechanisms of biomarker 8-Cl- and 8-oxo-purine derivatives were also investigated. Additionally, the structure-kinetic reactivity relationship study reveals a good correlation between lg kobs-est and APT charge in all purine compounds compared to FED2 (HOMO), which proves again that the electrostatic interaction plays a key role. The results are helpful to further understand the reactivity of various reaction sites in aromatic compounds during chlorination.

Appendicitis combined with Meckel's diverticulum obstruction, perforation, and inflammation in children: Three case reports.

BACKGROUND: Meckel's diverticulum is a common congenital malformation of the small intestine, with the three most common complications being obstruction, perforation, and inflammation. To date, only a few cases have been reported worldwide. In children, the clinical symptoms are similar to appendicitis. As most of the imaging features are nonspecific, the preoperative diagnosis is not precise. In addition, the clinical characteristics are highly similar to pediatric acute appendicitis, thus special attention is necessary to distinguish Meckel's diverticulum from pediatric appendicitis. Patients with poor disease control should undergo laparoscopic exploration to avoid serious complications, including intestinal necrosis, intestinal perforation and gastrointestinal bleeding. CASE SUMMARY: This report presents three cases of appendicitis in children combined with intestinal obstruction, which was caused by fibrous bands (ligaments) arising from the top part of Meckel's diverticulum, diverticular perforation, and diverticular inflammation. All three patients, aged 11-12 years, had acute appendicitis as their initial clinical presentation. All were treated by laparoscopic surgery with a favorable outcome. A complete dataset including clinical presentation, diagnostic imaging, surgical information, and histopathologic findings was also provided. CONCLUSION: Preoperative diagnosis of Meckel's diverticulum and its complications is challenging because its clinical signs and complications are similar to those of appendicitis in children. Laparoscopy combined with laparotomy is useful for diagnosis and treatment.

Computational Investigations of Reaction Mechanisms and Transformation Products of Olefins with Hypochlorous Acid.

Hypochlorous acid (HOCl) as the main component in chlorination and also as the innate immune factor relevant to immune defense has attracted considerable attention. Electrophilic addition reaction of olefins with HOCl, one of the most important prototype of chemical reactions, has been intensively studied for a long time; however, it has not been fully understood yet. In this study, addition reaction mechanisms and transformation products of model olefins with HOCl were systematically investigated by the density functional theory method. The results indicate that the traditionally believed stepwise mechanism with a chloronium-ion intermediate is only suitable for olefins substituted with electron-donating groups (EDGs) and weak electron-withdrawing groups (EWGs) but it is a carbon-cation intermediate that is favorable for EDGs featuring p-π or π-π conjugation with the C═C moiety. Moreover, olefins substituted with moderate or/and strong EWGs prefer the concerted and nucleophilic addition mechanisms, respectively. Epoxide and truncated aldehyde as the main transformation products can be generated from chlorohydrin through a series of reactions involving hypochlorite; however, their generation is kinetically not as feasible as the formation of chlorohydrin. The reactivity of three chlorinating agents (HOCl, Cl2O, and Cl2) and the case study of chlorination and degradation of cinnamic acid were also explored. Additionally, APT charge on the double-bond moiety in olefin and energy gap (ΔE) between the highest occupied molecular orbital (HOMO) energy of olefin and the lowest unoccupied molecular orbital (LUMO) energy of HOCl were found to be good parameters to distinguish the regioselectivity of chlorohydrin and reactivity of olefin, respectively. The findings of this work are helpful in further understanding the chlorination reactions of unsaturated compounds and identifying complicated transformation products.

Insights into C-C Bond Cleavage Mechanisms in Dichloroacetonitrile Formation during Chlorination of Long-Chain Primary Amines, Amino Acids, and Dipeptides.

Dichloroacetonitrile (DCAN) as one of the potentially prioritized regulated DBPs has drawn great attention; however, understanding its formation, especially the C-C bond cleavage mechanisms, is limited. In this study, DCAN formation mechanisms from long-chain primary amines, amino acids, and dipeptides during chlorination were investigated by a combined computational and experimental approach. The results indicate that nitriles initially generate for all of the above precursors, then they undergo ß-C-hydroxylation or/and α-C-chlorination processes, and finally, DCAN is produced through the Cα-Cß bond cleavage. For the first time, the underlying mechanism of the C-C bond cleavage was unraveled to be electron transfer from the O- anion into its attached C atom in the chlorinated nitriles, leading to the strongly polarized Cα-Cß bond heterocleavage and DCAN- formation. Moreover, DCAN molar yields of precursors studied in the present work were found to be determined by their groups at the γ-site of the amino group, where the carbonyl group including -CO2-, -COR, and -CONHR, the aromatic group, and the -OH group can all dramatically facilitate DCAN formation by skipping over or promoting the time-consuming ß-C-hydroxylation process and featuring relatively lower activation free energies in the C-C bond cleavage. Importantly, 4-amino-2-hydroxybutyric acid was revealed to possess the highest DCAN yield among all the known aliphatic long-chain precursors to date during chlorination. Additionally, enonitriles, (chloro-)isocyanates, and nitriles can be generated during DCAN formation and should be of concern due to their high toxicities.

Comparison of nitrate formation mechanisms from free amino acids and amines during ozonation: a computational study.

Nitrate as a potential surrogate parameter for abatement of micropollutants, oxidant exposure, and characterizing oxidant-reactive DON during ozonation has attracted extensive attention, however, understanding of its formation mechanisms is still limited. In this study, nitrate formation mechanisms from amino acids (AAs) and amines during ozonation were investigated by the DFT method. The results indicate that N-ozonation initially occurs to produce competitive nitroso- and N,N-dihydroxy intermediates, and the former is preferred for both AAs and primary amines. Then, oxime and nitroalkane are generated during further ozonation, which are the important last intermediate products for nitrate formation from the respective AAs and amines. Moreover, the ozonation of the above important intermediates is the nitrate yield-controlling step, where the relatively higher reactivity of the CN moiety in the oxime compared to the general Cα atom in the nitroalkane explains why the nitrate yields of most AAs are higher than those from general amines, and it is the larger number of released Cα- anions, which are the real reaction sites attacked by ozone, that leads to the higher nitrate yield for nitroalkane with an electron-withdrawing group bound to the Cα atom. The good relationship between nitrate yields and activation free energies of the rate-limiting step (ΔG≠rls) and nitrate yield-controlling step (ΔG≠nycs) for the respective AAs and amines verifies the reliability of the proposed mechanisms. Additionally, the bond dissociation energy of Cα-H in the nitroalkanes formed from amines was found to be a good parameter to evaluate the reactivity of the amines. The findings here are helpful for further understanding nitrate formation mechanisms and predicting nitrate precursors during ozonation.

Identification of chlorinated products from tyrosine and tyrosyl dipeptides during chlorination: a computational study.

Chlorinated amino acids and peptides, as the model modified protein structures relevant to pathogen inactivation and an emerging class of disinfection byproducts (DBPs) with potential health risks to humans, have attracted much attention. However, due to a large variety of peptides (over 600) identified in source water and most of them featuring multiple reaction sites, it is a huge challenge to identify all the chlorinated amino acids and peptides. As a good complement to the experiment, quantum chemical computation can be used to uncover the chlorination sites and chlorinated products. In this study, frequently detected tyrosine (Tyr) and tyrosine-amide (Tyr-Am) as well as N-acetyl-tyrosine (NacTyr) were chosen as the model amino acid and model dipeptides, respectively. The results indicate that the kinetic reactivity order of reactive sites with estimated apparent rate constants (kobs-est, in M-1 s-1) is amino N (107-8) ≫ mono-chlorinated amino N (101-3) >/≈ phenol ortho-C (100-3) ≫ meta-C (10-3), and phenol ortho-C5 (102-3) > ortho-C3 (100-2) for dipeptides, while in thermodynamics, phenol C sites are more favorable than amino N sites. Moreover, due to the smaller differences of kobs-est values between the mono-chlorinated amino N and the phenol ortho-C sites in tyrosyl dipeptides compared to free Tyr, more kinds of C-chloro-tyrosyl dipeptides are likely to be generated. Additionally, a structure-kinetic reactivity relationship study reveals good correlations between lg kobs-est and NPA charges and BDEs of protons released from amino/hydroxyl groups in tyrosyl compounds rather than FED2 (HOMO). The results are helpful to further understand the reactivity of various reaction sites in peptides and identify chlorinated products from tyrosyl peptides during chlorination.

Transformation mechanisms of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination: A computational study.

As an alternative disinfectant to free chlorine, monochloramine reduces the formation of regulated disinfection byproducts (DBPs); however, it also contributes to the formation of highly toxic nitrogenous DBPs (N-DBPs), especially through the aldehyde pathway. The current understanding of aldehyde pathway mechanisms is limited. In this study, the transformation pathways of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination were investigated using quantum chemical calculations. Consistent with previous studies, 1-chloroamino alcohol first forms in the chloramination of aldehydes and then undergoes competitive dehydration and HCl elimination branch reactions to generate the nitrile and (N-chloro)amide, respectively. Iminol was found to be a key intermediate for (N-chloro)amide formation. Moreover, the results indicated that acetaldehydes substituted with electron-donating groups (EDGs) and electron-withdrawing groups (EWGs) are beneficial to the formation of the respective nitriles and N-chloro-amides, while those substituted with conjugated groups (CGs) are favourable for both. Based upon the above results, in addition to acetaldehyde, other aldehydes, such as propionaldehyde, glycolaldehyde, 3-butenal, and phenylacetaldehyde, which are the α-H of acetaldehydes substituted with -CH3, -OH, -CH=CH2, and -C6H5 groups, respectively, are potential precursors of toxic nitriles and (N-chloro)amides during chloramination. Thus, more attention should be given to these aldehydes. The findings of this work are helpful for further understanding the aldehyde pathway mechanisms and predicting potential precursors of toxic nitriles and (N-chloro)amides during chloramination.

Reaction Mechanisms of Histidine and Carnosine with Hypochlorous Acid Along with Chlorination Reactivity of N-Chlorinated Intermediates: A Computational Study.

Hypochlorous acid (HOCl) released from activated leukocytes not only plays a significant role in the human immune system but is also implicated in numerous diseases including atherosclerosis and some cancers due to its inappropriate production. Histidine (His) and carnosine (Car), as a respective mediator and protective agent of HOCl damage, have attracted considerable attention; however, their detailed reaction mechanisms are still unclear. In this study, using a His residue with two peptide bond groups (HisRes) as a model, the reaction mechanisms of HisRes and Car including NεH and NδH tautomers with HOCl along with the chlorination reactivity of N-chlorinated intermediates were investigated by quantum chemical methods. The obtained results indicate that in the imidazole side chain, the pyridine-like N is the most reactive site rather than the pyrrole-like N, and the kinetic order of all of the possible reaction sites in HisRes follows pyridine-like N > imidazole Cδ ≫ imidazole Cε > pyrrole-like N, while that in Car is pyridine-like N ≫ imidazole Cδ ≫ amide N. As for N-chlorinated intermediates at imidazole, although the unprotonated form has a low chlorination reactivity as expected, it can still chlorinate tyrosine. Especially, the protonated form exhibits similar ability to HOCl, causing secondary damage in vivo. N-Chlorinated Car features higher internal chlorine migration ability than its intermolecular transchlorination, preventing further HOCl-induced damage. Additionally, a generally overlooked nucleophilic Cl- shift is also found in N-chlorinated Car/HisRes, indicating that nucleophilic sites in biomolecules also need to be considered. The outcomes of this study are expected to expand our understanding of secondary damage and protective mechanisms involved in HOCl in humans.

Formation mechanism of chloropicrin from amines and free amino acids during chlorination: A combined computational and experimental study.

Chloropicrin as one of the most frequently detected N-DBPs has drawn great attention due to its high toxicity. However, our understanding of its formation mechanism is still very limited. A combined computational and experimental approach was used in this study to reveal chloropicrin formation mechanism during chlorination. Ethylamine, n-propylamine, alanine and tryptophan along with the above two amines and their four derivatives substituted by -OH or/and -NO2 groups were chosen as computational and experimental model precursors, respectively. The results indicate that primary amines and free amino acids are more likely to share the same chloropicrin formation pathway including N-chlorination, imidization, ß-C-alcoholization, N-nitration, α-C-chlorination and dealdehydation processes. Moreover, elimination of hydrochloric acid from N,N-dichloro-amine and electrophilic addition of N-chloroalkylimide with hypochlorous acid were found to be the rate-limiting steps among all the elementary reactions. By skipping over both of the above rate-limiting steps, RCH(OH)CH2NO2 and RCH(OH)CH2NH(OH) compounds were proposed to be potent chloropicrin precursors, and experiments confirmed that 2-nitroethanol and N-methylhydroxylamine have the highest chloropicrin yields in the chlorination among all the precursors reported to date. The findings of this work are helpful for expanding the knowledge of chloropicrin formation mechanisms and predicting the potential chloropicrin precursors.

Degradation mechanisms of simple aliphatic amines under ozonation: a DFT study.

Aliphatic amines as common constituents of dissolved organic nitrogen (DON) exhibit high reactivity during ozonation; however, our understanding of their degradation mechanisms is very limited. In this study, methylamine (MA) and ethylamine (EA), as well as their secondary and tertiary amines (DMA, DEA, TMA and TEA) were chosen as aliphatic amine models and their degradation mechanisms during ozonation were investigated by using the DFT method. The oxygen-transfer reaction occurs initially and rapidly in the ozonation of all the above amines with a ΔG≠ value of 8-10 kcal mol-1 in great agreement with the experimental rate constant of 104 to 107 M-1 s-1. Moreover, N-oxide as the main degradation product for tertiary amines directly forms after oxygen-transfer, while nitroalkanes as main products for secondary and primary amines are yielded after a series of reactions mediated by hydroxylamine and nitrosoalkane with a ΔG≠ value of 10-13 kcal mol-1. Regarding the minor N-dealkylated products for all amines, alkylamino alcohol is an important intermediate possibly generated via a radical reaction pathway with a ΔG≠ value of 21-34 kcal mol-1. Additionally, comparison of the reactivity of aliphatic amines, hydroxylamines and alkylamino alcohols with ozone was made and elucidated in this study. The results are expected to expand our understanding of the degradation mechanisms for nitrogenous compounds during ozonation.

IRF7 suppresses hematopoietic regeneration under stress via CXCR4.

Hematopoietic stem cells (HSCs) maintain quiescence under steady state; however, they are compelled to proliferate and expand to replenish the blood system under stress. The molecular basis underlying stress hematopoiesis remains to be fully understood. In this study, we reported that IRF7 represents an important regulator of stress hematopoiesis. Interferon regulatory factor 7 (IRF7) was dispensable for normal hematopoiesis, whereas its deficiency significantly enhanced hematopoietic stem and progenitor cells (HSPCs) regeneration and improved long-term repopulation of HSCs under stress. Mechanistic studies showed that CXCR4 was identified as a downstream target of IRF7. Overexpression of CXCR4 abrogated the enhanced proliferation and regeneration of IRF7-deficient HSPCs under stress. Similar results were obtained in HSCs from human umbilical cord blood. These observations demonstrated that IRF7 plays an important role in hematopoietic regeneration under stress.

Treatment Patterns and Survival Outcomes of Non-Small Cell Lung Cancer Patients Initially Diagnosed With Brain Metastases in Real-World Clinical Practice.

BACKGROUND: This study aimed to comprehensively analyze the characteristics, treatment patterns, and survival outcomes of non-small-cell lung cancer (NSCLC) patients initially diagnosed with brain metastases (BMs) in real-world practice. METHODS: We enrolled NSCLC patients initially diagnosed with BMs between Jan 2004 and Jan 2018 in our institution. Patient demographics, treatment modalities, and survival outcomes were then analyzed. Brain localized treatment (BLT) included early brain radiotherapy (EBR), deferred brain radiotherapy (DBR), and surgery. RESULTS: A total of 954 patients were identified. Concerning initial treatment, 525 patients (55.0%) received systemic medication (SM)+BLT, 400 patients (41.9%) received SM only, and 29 patients received BLT only (3.0%). SM+BLT cohort was associated with longer median overall survival (mOS) than the SM only and the BLT only cohorts both in epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK)-negative/unknown patients (15.3 months, 95% confidence interval [CI], 14.2-16.4; 11.1 months, 9.0-13.2; 7.0 months, 5.4-8.6; p<0.001) and in EGFR/ALK-positive patients (33.7 months, 28.5-38.9; 22.1 months, 17.8-26.4; 4.0 months, 3.6-4.4; p < 0.001). As for timing of radiotherapy, SM+EBR (14.1 months, 12.7-15.5) was associated with inferior mOS than SM+DBR (19.4 months, 14.2-24.6) in EGFR/ALK-negative/unknown patients. No significant difference was found in EGFR/ALK-positive patients (28.3 months, 19.1-37.5; 33.3 months, 28.1-38.5). Patients in the EGFR/ALK-negative/unknown cohort treated with first-line pemetrexed with platinum (PP) (15.8 months, 14.0-17.6, p<0.001) had longer mOS than those received non-PP regimens (13.1 months, 11.6-14.6). However, no difference was observed among EGFR/ALK-positive patients who were treated with tyrosine kinase inhibitors (TKIs) (29.5 months, 21.1-37.9; p = 0.140), PP (27.2 months, 21.6-32.8) and non-PP regimens (25.0 months, 16.0-34.0). CONCLUSIONS: Our study confirmed that the use of SM+BLT is associated with superior mOS than those treated with SM only and BLT only. SM+DBR might be a better radiotherapeutic strategy for this patient population. EGFR/ALK-negative/unknown patients showed a survival benefit with PP treatment.

Degradation Mechanisms and Substituent Effects of N-Chloro-α-Amino Acids: A Computational Study.

N-Chloro-α-amino acids formed in the chlorination disinfection treatment of water or wastewater and in living organisms have attracted extensive attention due to the potential toxicities of themselves and their decomposition products. The degradation mechanisms of three N-chloro-α-amino acids, i.e., N-chloro-glycine, N-chloro-alanine, and N-chloro-valine, have been systematically investigated using quantum chemical computations. The results indicate that N-chloro-α-amino acid anions undergo two competitive degradation pathways: a concerted Grob fragmentation (CGF) and ß-elimination (ß-E). Generally, the former predominates over the latter under neutral conditions and finally generates amines and carbonyls, while the latter is preferred under base-promoted conditions and mainly produces the respective α-keto acid anions or nitriles in the end. To gain deeper insights into the substitution effects, in view of the advantages of quantum chemical computations, a number of real or designed N-chloro-α-amino acids with traditional electron-donating groups (EDG) or electron-withdrawing groups (EWG) have been studied. All of the substituted N-chloro-α-amino acids, regardless of the type and position of substituents, are kinetically more favorable than N-monochloro-glycine for degradation via the CGF pathway. Moreover, conjugated EDG substituted on the N-terminal facilitate both CGF and ß-E reactions, whereas conjugated EDG and EWG on the α-carbon are only favorable for the CGF and ß-E reactions, respectively. These results are expected to expand our understanding of organic N-chloramine degradation mechanisms and chlorination reaction characteristics.

Cyclooxygenase-1 Regulates the Development of Follicular Th Cells via Prostaglandin E2.

Cyclooxygenase (COX)-1, one of the critical enzymes required for the conversion of arachidonic acid to PGs, has been demonstrated to play an important role not only in the cardiovascular system but also in the immune system. COX-1 has been found to regulate early B cell differentiation, germinal center formation, and Ab production of B cells. However, the underlying mechanisms of COX-1-mediated B cell activation remains not fully understood. In this study, we reported that COX-1 is a potential regulator for the development of follicular Th (TFH) cells. COX-1-deficient (COX-1-/- ) mice displayed a significant reduction of TFH cells upon influenza infection or immunization with keyhole limpet hemocyanin, which led to a severe impairment of germinal center responses. We further demonstrated that COX-1-derived PGE2, via binding with its receptors EP2/EP4, represents the underlying mechanism. The administration of EP2/EP4 agonists or PGE2 almost completely rescued the defective TFH cell generation in COX-1-/- mice. Taken together, our observations indicate that COX-1 plays an important role in the development of TFH cells.

The formation mechanism of chloropicrin from methylamine during chlorination: a DFT study.

Chloropicrin (TCNM) as one of the most frequently detected nitrogenous disinfection byproducts (N-DBPs) has attracted extensive attention due to its high toxicity. Although much research work on TCNM has been done, its formation mechanism during chlorination has not been known clearly yet. In this study, TCNM formation mechanisms from methylamine (MA) during chlorination, including N-chlorination of MA by hypochlorous acid to generate dichloromethylamine (DCMA) first and then oxidation of DCMA to form nitromethane (NM) and chloronitromethane (CNM), and finally TCNM formation from C-chlorination of NM and CNM, were investigated by using the DFT method. The calculated results show that in N-chlorination of MA, 2-3 water molecules involved in the reaction facilitate Cl+ and proton transfer with the activation free energies (ΔG≠) for the first and second chlorination in the range of 4-7 and 14-17 kcal mol-1, respectively, which are in good agreement with the experimental results. Formation of NM and CNM proceeds through a series of elimination, addition, and oxidation reactions with ΔG≠ of the rate-limiting steps being around 34-37 kcal mol-1, and the subsequent C-chlorination of methyl in NM and CNM by hypochlorous acid is a rapid process with ΔG≠ below 7 kcal mol-1. This infers that the TCNM formation mechanism from DCMA is more likely to undergo first N-oxidation and then C-chlorination. These results can explain the experimental findings that the molar yield of TCNM from MA during chlorination is low (<0.1%) whereas that from NM is rather high (∼45%). This work will be helpful to elucidate formation mechanisms of all the halonitromethanes during chlorination.

Schisandrin B ameliorates high-glucose-induced vascular endothelial cells injury by regulating the Noxa/Hsp27/NF-κB signaling pathway.

BACKGROUND: To address the molecular mechanism of the anti-inflammation effects of schisandrin B (Sch B) in atherosclerosis, we examined injured HMEC-1, HBMEC, and HUVEC-12 cells induced by high glucose (HG). METHODS: Western blot was performed to detect the levels of the proteins Hsp27, Noxa, TLR5, p-IκBα, and p-p65 in HG-induced cells, while ELISA was used to analyze the inflammatory cytokines TNF-α, IL-6, MCP-1, and IL-1ß in cells with Hsp27 or Noxa stable expression. RESULTS: Overexpression of Hsp27 upregulated the inflammatory cytokines and the release of IκBα, promoted transportation of p65 into the nucleus, and lastly, affected the inflammation process, while Sch B counteracted the upregulation. In addition, the effect of Noxa overexpression, which is different from Hsp27 overexpression, was consistent with that of Sch B treatment. CONCLUSIONS: Sch B may inhibit the inflammatory cascade and alleviate the injury to HMEC-1, HBMEC, and HUEVC-12 cells caused by HG by regulating the Noxa/Hsp27/NF-κB signaling pathway.

NDMA formation mechanisms from typical hydrazines and hydrazones during ozonation: A computational study.

N-nitrosodimethylamine (NDMA) as the most frequently detected disinfection by-product has aroused widespread concern due to its unusually high carcinogenicity, however, there is still limited understanding of its formation mechanisms. In this study, the formation mechanisms of NDMA from some typical hydrazines and hydrazones with high NDMA conversion yields (60%∼90%) during ozonation, i.e., unsymmetrical dimethylhydrazine (UDMH), 1-formyl-2,2-dimethylhydrazine (FDMH), formaldehyde dimethylhydrazone (FDH) and acetone dimethylhydrazone (ADMH), were investigated by using DFT method with the M05 functional. A new NDMA formation mechanism from hydrazines during ozonation was proposed, in which the initial step is hydrogen abstraction rather than previously reported oxygen addition. For hydrazones, the C atom of the -N = C moiety in hydrazones is preferred to be attacked by ozone to generate N,N-dimethylaminonitrene (DMAN), which is an important intermediate in NDMA formation during ozonation. Moreover, the reactivity order of the following H atoms in hydrogen/hydride ion abstraction (HA) by ozone is -NH2 > -N(CH3)2 > -CO-NH ∼ =C(CH3)2 > =CH-. Additionally, formation pathways of some experimentally detected compounds, i.e., HOOOH, HOOH and HCOH, in the ozonation of hydrazine were elucidated in this study. The results are expected to expand our understanding of NDMA formation mechanisms and ozone reaction characteristics.

Prognostic Value of Lymphocyte Activation Gene-3 (LAG-3) Expression in Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor with a high incidence in East Asia and the Middle East. The outcomes for ESCC patients are usually not optimal due to the recurrence and metastasis. This study is aim to examine the expression and the prognostic value of LAG-3 in ESCC. We applied immunohistochemistry analysis to examine the expression of LAG-3, CD4 and CD8 in 287 ESCC cohorts. Our study demonstrated that the decreased LAG-3 expression was significantly associated with CD4 tumor-infiltrated lymphocytes (TILs) (p=0.000), CD8 TILs (p=0.000), and the advanced clinical stages (p=0.041) by Chi-square analysis. Kaplan-Meier survival analysis revealed that higher LAG-3 expression were positively correlated with a better overall survival (OS) (p=0.010) and better progression free survival (PFS) (p=0.006), especially in the patients at stages T1-2 status (p=0.001, OS; p=0.001, PFS), N0 status (p=0.036, OS; p=0.050, PFS), and early stages (I-II) (p=0.006, OS; p=0.008, PFS). Both high of CD4 TIL /CD8 TIL ratio and LAG-3 expression were correlated with longer OS and PFS. Cox proportional hazards regression analysis showed that LAG-3 is an independent biomarker of survival (HR, 0.724; 95% CI 0.526-0.995; p = 0.047) (p=0.036). Taken together, we found that high expression of LAG-3 was correlated with an improved survival and LAG-3 is an independent predictor of survival, suggesting that LAG-3 may serve as a useful immune marker for the prognosis of ESCC.

High levels of CCL2 or CCL4 in the tumor microenvironment predict unfavorable survival in lung adenocarcinoma.

BACKGROUND: Tumor-associated immune factors are heterogeneous and play an important role in determining outcome in cancer patients. In this study, the expression levels of immune factors in tumor tissue-conditioned media from lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) were analyzed. METHODS: LUAD and LUSC tissue specimens were collected immediately after surgery for antibody array analysis and real-time quantitative PCR. RESULTS: Higher levels of chemokines MCP1/CCL2 (21.11-fold increase) and MIP-1ß/CCL4 (19.33-fold increase) were identified in LUAD than in LUSC. Western blot and quantitative real-time PCR analyses showed higher co-expression of CCL2 and CCL4 in LUAD tissues compared to LUSC (P < 0.0001). Immunofluorescent co-staining showed a high percentage of CCL2+ /CD68+ and CCL4+ /CD68+ tumor-associated macrophages in LUAD compared to LUSC tissues, which might be responsible for the higher expression of CCL2 and CCL4 in LUAD samples. Kaplan-Meier curves showed that CCL2 overexpression in patients with LUSC was associated with beneficial overall survival (OS; P = 0.048) and progression-free survival (PFS; P = 0.012); however, LUAD patients with higher CCL2 expression had unfavorable OS (P = 6.7e-08) and PFS (P = 0.00098). Similarly, CCL4 overexpression predicted favorable PFS (P = 0.021) in patients with LUSC, but patients with high CCL4 levels in LUAD had shorter OS (P = 0.013). CONCLUSION: Our study revealed that CCL2 and CCL4 expression levels could serve as potential prognostic biomarkers and therapeutic targets for NSCLC patients.