The physicochemical properties and potential hemostatic application of Wenchang kaolin and Maoming kaolin were inspected and evaluated. Chemical composition analysis, Fourier transform infrared (FTIR) spectroscopy, surface area determination, X-ray diffraction, particle size, scanning electron microscopy (SEM) observations, and zeta potential analysis were performed to quantify the physical and chemical properties of the two kaolins. The results showed that both kaolins have typical FTIR bands of kaolinite with a weight fraction for kaolinite over 90 wt%. Larger conglobate aggregates of Maoming kaolin demonstrated wider particle size distributions with two peaks at 3.17 and 35.57 μm, while the book-like Wenchang kaolin had narrow particle size distribution, with a frequent size of 5.64 μm. Furthermore, thrombelastography, the whole blood clotting tests (WBCT), plasma recalcification time (PRT) measurement, and MTT assay were performed to measure the clotting activities and biocompatibility of the two kaolins. The results showed that both kaolins could promote blood coagulation with good cytocompatibility, while Wenchang kaolin had a better procoagulant activity than Maoming kaolin. These findings demonstrated Wenchang kaolin to be a more suitable local source material for application as a hemostatic agent.

No abstract

Botulinum neurotoxin (BoNT), produced by Clostridium botulinum, is generally known to be the most poisonous of all biological toxins. In this study, we evaluate the protection conferred by intratracheal (i.t.) inoculation immunization with recombinant Hc subunit (AHc) vaccines against aerosolized BoNT/A intoxication. Three AHc vaccine formulations, i.e., conventional liquid, dry powder produced by spray freeze drying, and AHc dry powder reconstituted in water are prepared, and mice are immunized via i.t. inoculation or subcutaneous (s.c.) injection. Compared with s.c.-AHc-immunized mice, i.t.-AHc-immunized mice exhibit a slightly stronger protection against a challenge with 30,000× LD50 aerosolized BoNT/A. Of note, only i.t.-AHc induces a significantly higher level of toxin-neutralizing mucosal secretory IgA (SIgA) production in the bronchoalveolar lavage of mice. In conclusion, our study demonstrates that the immune protection conferred by the three formulations of AHc is comparable, while i.t. immunization of AHc is superior to s.c. immunization against aerosolized BoNT/A intoxication.

The current study explores the detoxification effect of Retro‐2 on ricin toxin (RT) cytotoxicity, as well as the mechanisms underlying such effects, to provide a basis for follow‐up clinical applications of Retro‐2. The mouse‐derived mononuclear/macrophage cell line, RAW264.7, was used to evaluate the detoxification effect of Retro‐2 on RT by detecting cell viability, capacity for protein synthesis and the expression of cytokines, as well as endoplasmic reticulum stress (ERS)‐related mRNA. The results indicated that many cells died when challenged with concentrations of RT ≥50ng/mL. The protein synthesis capacity of cells decreased when challenged with 200ng/mL RT for 2hours. Furthermore, the synthesis and release of many cytokines decreased, while the expression of cytokines or ERS‐related mRNA increased when challenged with 200ng/mL of RT for 12 or more hours. However, cell viability, capacity for protein synthesis and release levels of many cytokines were higher, while the expression levels of cytokine, or ERS‐related mRNA, were lower in cells pretreated with 20μm Retro‐2 and challenged with RT, compared with those that had not been pretreated with Retro‐2. In conclusion, Retro‐2 retained the capacity for protein synthesis inhibited by RT, alleviated ERS induced by RT and increased the viability of cells challenged with RT. Retro‐2 shows the potential for clinical applications.

Lipopolysaccharide (LPS) is one of the main constituents of the cell wall in Gram-negative bacteria. Staphylococcal enterotoxin B (SEB) is produced by the Gram-positive opportunistic pathogen, Staphylococcus aureus. Emerging evidence suggests that intraperitoneal injection of LPS combined with low-dose aerosolized SEB exposure can cause severe lung injury and even death, while SEB or LPS alone cause neither mortality nor severe pulmonary symptoms in mice. However, pulmonary effects from exposure to aerosolized SEB potentiated by LPS have not been evaluated. This study investigates the global transcriptome profile of lung tissue in mice after exposure to aerosolized SEB potentiated by LPS or LPS alone. A mouse model of intratracheal exposure to LPS-potentiated aerosolized SEB is established and described through histological examination. Transcriptome analysis revealed LPS-potentiated aerosolized SEB affected mouse lungs within 72 h post-SEB inhalation, gradually causing lung injury starting from 24 h post inhalation. Hub genes leading to lung injury at 48 h post inhalation have been identified. Flow cytometry revealed that LPS potentiation of low-dose SEB produces a superantigen response that T cells expressing a particular T cell receptor Vβ induces a proliferation response by 72 h post inhalation in the lungs of mice. This study represents the first research to investigate pulmonary transcriptional responses of LPS-potentiated aerosolized low-dose SEB exposure. This research helps to elucidate the molecular mechanisms underlying the process by which the two bacterial components combined to produce lung damage and provides an insight into potential treatments for alleviating inflammation of the lung when coinfection is present.