Chemical analysis of selected harmful and potentially harmful constituents and in vitro toxicological evaluation of leading flavoured e-cigarette aerosols in the Chinese market

Use of electronic cigarettes (e-cigarettes) has increased significantly over the past decade due to consumer perception that these products represent a less risky alternative to combustible cigarettes. E-liquids generally contain a simple mix of vegetable glycerin, propylene glycerol, nicotine, organic acids, and flavourings. Regulators require that harmful and potentially harmful constituents (HPHCs) that might cause harm to the consumer must be monitored in the aerosol generated by e-cigarettes and in cigarette smoke (CS). To quantify HPHCs in aerosols from commercial flavoured e-cigarettes in Chinese market, this study has systematically compared levels of HPHCs, including eight carbonyls, five volatile organic compounds, four tobacco-specific nitrosamines, 16 polycyclic aromatic hydrocarbons, and seven heavy metals, in the aerosols of four market-leading flavoured e-cigarettes and mainstream CS, alongside in vitro cytotoxicity and mutagenicity assays. The vast majority of HPHCs were either undetected or significantly lower in the e-cigarette aerosols than in commercial CS or reference CS (3R4F). Where HPHCs were detected, there were small variations among the different flavoured e-cigarettes. In the neutral red uptake and Ames assays, aqueous extracts of the e-cigarette aerosols did not induce obvious cytotoxicity or mutagenicity, whereas CS aqueous extract showed dose-related cytotoxicity and mutagenicity. Collectively, these results indicate that use of e-cigarettes might potentially lead to a significant reduction in exposure to harmful substances, with fewer cytotoxic and mutagenic effects, as compared with conventional smoking. Further studies based on human puffing conditions and longer evaluation periods will be needed to substantiate this potential.

[Questions and reflections in the diagnosis and treatment of younger breast cancer in China]

Compared with the median age of breast cancer onset in western countries at 62-64 years, the median age in China is around 16 years earlier. There are nearly fifty thousand new breast cancer patients younger than 40 years in China every year. The tumor characteristics, diagnosis and treatment methods, and psychosocial needs of these young patients are often different from elder breast cancer patients. Currently, the international clinical guidelines for young breast cancer are mainly formulated by western countries, which often do not address the unique clinical needs from young breast cancer patients in China. There are many questions and problems in the diagnosis and treatment of young breast cancer in China that do not have standard answer and are urgently in need of expert consensus to guide clinical decision-making.

Comparison of biological and transcriptomic effects of conventional cigarette and electronic cigarette smoke exposure at toxicological dose in BEAS-2B cells

Cigarette seriously affects human health, and electronic cigarette (e-cigarette), considered as cigarette substitutes, become popular as its contribution to quit smoking. But scientific evidence about the absolute safety of e-cigarette is insufficient. Previous studies also have indicated that different dosages of cigarette can lead to different biological effects. Thus, the impact of cigarette at toxicological dose such as IC50 compared with that of e-cigarette are highly needed. In this study, we investigated the effects of cigarette smoke condensate (CSC) at toxicological dose compared with e-cigarette smoke condensate (ECSC) in equivalent nicotine level. Nicotine content of CSC and ECSC were determined by UPLC. Human lung epithelial cells (BEAS-2B) were exposed to 0-32 μg/ml of CSC and ECSC for 24 h to determine IC50 of cell viability and morphological assessment. Inflammation, apoptosis, cell cycle analysis and RNA-Seq transcriptome analysis were performed to characterize the differences between CSC and ECSC. We found that acute exposure of BEAS-2B cells to CSC at IC50 leaded to morphological change, inflammatory cytokines production and cell apoptosis, while ECSC did not exert such cell effects in equivalent nicotine level. The transcriptome analysis showed that differentially expressed genes in CSC were far more than that in ECSC, and mainly enriched in the category of cell cycle, DNA repair, cancer, and metabolic related pathways. Such cell cycle arrest was further experimentally confirmed. These results suggested that toxicological dose of ECSC might be much higher than that of CSC. Based on equivalent nicotine content, an acute exposure to CSC had significant impacts on cell effects and gene expression profile compared to ECSC. Our results provided a reference for the safety studies of conventional cigarette and e-cigarette.

Acute and subacute inhalation toxicity assessment of WS-23 in Sprague-Dawley rats

2-isopropyl-N,2,3-trimethylbutyramide (WS-23) is a well-known artificial synthesis cooling agent widely used in foods, medicines, and tobaccos. As a commonly cooling agent in e-cigarette liquids, WS-23 has led to concerns about the inhalation toxicity with the prosperous of e-cigarettes in recent years. Thus, the aim of this study is to assess the acute and subacute inhalation toxicity of WS-23 in Sprague-Dawley (SD) rats according to the Organization for Economic Cooperation and Development (OECD) guidelines. In the acute toxicity study, there was no mortality and behavioral signs of toxicity at the limit test dose level (340.0 mg/m³ ) in the exposure period and the following 14-day observation period. In the subacute inhalation toxicity study, there was no significant difference observed in the body weights, feed consumption, and relative organ weights. Haematological, serum biochemical, urine, and bronchoalveolar lavage fluid (BALF) analysis revealed the non-adverse effects after 28-day repeated WS-23 inhalation (342.85 mg/m³ ), accompanied by slight changes in few parameters which returned to normal during the 28-day recovery period. The histopathologic examination also did not show any differences in vital organs. In conclusion, the maximum tolerated dose for WS-23 acute inhalation is not less than 340.0 mg/m³ , and the No Observed Adverse Effect Level (NOAEL) of WS-23 subacute inhalation was determined to be over 342.85 mg/m³ .

Triptolide reverses the Taxol resistance of lung adenocarcinoma by inhibiting the NF-κB signaling pathway and the expression of NF-κB-regulated drug-resistant genes

Paclitaxel (or Taxol®) is a first-line chemotherapeutic drug for the treatment of non-small cell lung cancer; however, resistance to the drug is an important factor, which influences the outcome of chemotherapy. The present study aimed to investigate the role of triptolide (TPL) in reversing Taxol‑resistant human lung adenocarcinoma and to elucidate the underlying molecular mechanism of resistance reversal mediated by TPL. It was hypothesized that this experimental approach would assist in solving the problem of chemotherapeutic resistance in non‑small cell lung cancer, thereby improving the clinical outcomes. The human Taxol‑resistant lung adenocarcinoma cell line, A549/Taxol, was established. The resistance index of the cell line was calculated, according to the half maximal inhibitory concentration (IC50) of A549/Taxol IC50 of A549, to be 51.87. The levels of apoptosis and the cell cycle in the A549/Taxol cell line were assessed to confirm the effects of TPL at three different concentrations (0.03, 0.3 and 3 µmol/l) and treatment durations (2, 4, 6 and 12 h) by flow cytometric analysis, and the inhibition of the NF‑κB signaling pathway and the expression of NF‑κB‑regulated drug‑resistant proteins were determined by immunofluorescence and western blotting, respectively. The administration of TPL promoted cell apoptosis in the A549/Taxol lung adenocarcinoma Taxol‑resistant cell line and also promoted cell cycle regulation. The drug was also able to elicit a reversal of the drug resistance. TPL inhibited the nuclear factor‑κB (NF‑κB) signaling pathway and the expression of NF‑κB‑regulated drug‑resistant genes, including those for FLICE‑like inhibitory protein, X‑linked inhibitor of apoptosis protein, Bcl‑2, Bcl‑xL and cyclo‑oxygenase‑2. TPL exerted a marked drug‑resistance‑reversal effect on human lung adenocarcinoma Taxol resistance, and the effect was revealed to be dose‑ and time‑dependent. In conclusion, TPL exerted its role in the process of resistance reversal by inhibiting the NF‑κB signaling pathway, and the transcription and expression of NF-κB-regulated drug-resistant genes.

CC chemokine ligand 21 enhances the immunogenicity of the breast cancer cell line MCF-7 upon assistance of TLR2

CC chemokine ligand 21 (CCL21) is a known attractant for CCR7-positive (CCR7+) cells, but its additional role in the immunogenicity of CCR7+ cells remains poorly understood. This study explored the effects of CCL21-CCR7 ligation on cancer immunogenicity and related antitumor immune response, in the presence and absence of mitomycin C (MMC) treatment. CCL21-CCR7 binding upregulated human leukocyte antigen class I-restricted tumor antigen presentation with increased expression of human leukocyte antigen class I and transporter associated with antigen processing-1. In addition, CCL21 restrained the tumor-derived immunosuppressive factors FasL and transforming growth factor-β. Consequently, CCL21 facilitated cancer-educated lymphocytes reaction in vitro. In the tumor-bearing mouse, CCL21 inhibited tumor growth and prolonged mouse survival via lymphocytes, especially in CCR7+ cancer cells. Furthermore, Toll-like receptor 2 activation of lymphocytes assisted the tumor-suppression functions of CCL21, in vitro and in vivo. This study implies that CCL21 improved the immunogenicity of the CCR7+ breast cancer cell line even with MMC treatment and triggered antitumor response by lymphocytes. These findings provide a new insight into the research and application of CCL21-associated antitumor response.

[Determination of liquid-crystalline transition temperature of temperature-sensitive liposomes of futraful by 1HNMR]

1HNMR was employed to determine the liquid-crystalline transition temperature (TC) of the temperature-sensitive liposomes of futraful. It is a method with high sensitivity, high accuracy and furnishing more information. The 1HNMR spectra were made and studied. The rate of peak height increase of phospholipid correlates to the thermotropic phase transition of liposomes. The study shows that the TC of DPPC-liposomes and DSPC-liposomes is 36 degrees C and 48 degrees C, respectively. The TC of DPPC-DSPC-liposomes correlates with the proportion of the amount of DPPC and DSPC. The TC is not affected by futraful. The temperature-sensitive liposomes of futraful with TC of 41 degrees C were prepared which consisted of 60% DPPC and 40% DSPC.

Design and synthesis of amidino-tyrosine derivatives as non-peptide fibrinogen receptor antagonists

The design, synthesis and antiaggregation activity of amidino-tyrosine derivatives based on Arg-Gly-Asp (RGD) tripeptide sequence as non-peptide fibrinogen receptor antagonists is described. Optimization of the spacer and the substituent at the C-terminal is reported.

[Studies on oral sustained-release microspheres of nifedipine]

Nifedipine has been incorporated into Eudragit RL microspheres by the emulsion solvent-evaporation process using an acetone/liquid paraffin system. The drug in the Eudragit RL microspheres was present in either molecular dispersion or amorphous state. The drug release profile from microspheres conformed to the Higuchi equation. The microspheres were stable under different storage conditions for six months with respect to drug content, dispersing state and release profile. The in vivo results in eight healthy volunteers showed that the relative bioavailability of the nifedipine sustained-release microspheres against commercial retard tablet as a control was 102.5%, and the microsphere formulation was bioequivalent to the retard tablet. Significant in vitro and in vivo correlation was also found for the microspheres.

[Preparation and in vitro activity of monoclonal antibody-pharmorubicin immunoconjugates]

Bifunctional agent adipic dihydrate was used to form hydrazon bond between polyglutamic acid (PGA) and pharmorubicin (PAR). Under controlled condition, a relatively high rate of conjugation was obtained with no self-condensation. The value of PGA/PAR was in positive portion with the molecular weight (MW) of PGA: per 8-11 glutamic acid monomer linking one pharmorubicin. When PGA of MW 14,300 was used as carrier, the ratio of PGA/PAR was 1:11. After conjugating with anti-hepatoma monoclonal antiboty (McAb), an immunoconjugate of McAb:PGA:PAR being 1:2:22 was obtained. The immunoconjugate retained the binding activity to targeted cell compared with the purified and the oxidized antibody. Pharmacological studies in vitro showed lower cytotoxicity of the immunoconjugate than the free drug, but selective cytotoxicity directed by antibody was observed. Consequently, the immunoconjugate McAb-PGA-PAR with high ratio of drug/McAb as well as moderate targeting cytotoxity in vitro was successfully prepared. That makes it possible for the preparation of cell-targeted drug which is expected to be benificial to tumor treatment.

[Effects of beta-agkistrodotoxin on synaptic transmission in toad sympathetic ganglia]

The effects of beta-agkistrodotoxin (beta-AgTX) on synaptic transmission of the toad sympathetic ganglia were investigated by intracellular recording techniques. Superfusion of beta-AgTX (30 microgram/ml, 5-15 min) reversibly inhibited the cholinergic fast excitatory postsynaptic potential (f-EPSP, n = 16) and the fast components of acetylcholine (ACh) potential induced by micropressure administration of ACh (n = 24). Comparison of beta-AgTX effect in the same cell group showed significantly different inhibition rates on f-EPSP (77.2 +/- 27.7%) and ACh potential (25.5 +/- 17.5%) (n = 6, P less than 0.01, F test). During application of beta-AgTX (30 or 50 micrograms/ml) for 15-30 min, no detectable change was found in non-cholinergic late slow EPSPs (n = 22). The results suggest that beta-AgTX selectively inhibits the cholinergic transmission of the toad sympathetic ganglia by both presynaptic and postsynaptic mechanism.

Experimental study on topical antimicrobial agents in burns

Numerous organic silver salts have been tested against a virulent strain of Pseudomonas aeruginosa which had been deliberately applied to the scalded tails of mice and deeper scald wounds on the backs of rabbits. Silver pipemidate was found to be more effective than silver sulphadiazine in treating these infected wounds.