Assessing the toxicant effect of spontaneously volatilized 4-vinylcyclohexane exposure in nymphs of the lobster cockroach nauphoeta cinerea

Vinylcyclohexene (VCH) is an environmental contaminant well known for its ovotoxicant effects in several organisms. However, the mechanisms underlying the toxicity of VCH as well as its harmful effects toward other organs are until unclear. In this work, we assess some endpoint signals of toxicity induced by volatilized VCH exposure using nymphs of the lobster cockroach Nauphoeta cinerea. Nymphs were exposed to VCH via inhalation for 70 days. The levels of volatilized VCH were quantified by headspace gas chromatography and the concentration varied between 3.41 and 7.03 nmol/μl. VCH inhalation caused a reduction of 35% in the survival rate of the exposed animals. Nymphs exposed to volatilized VCH for 35 and 70 days had a reduction in the body weight gain of 1.8− and 2.6−fold, respectively with a reduction in dissected head, fat body, and maturing reproductive organs. The exposure did not change water consumption, excepting on the 20th day (with a 3-fold change) and decreased the food intake significantly. Regarding biochemical markers, we found that the activity of GST from the dissected organs was increased by volatilized VCH after both 35 and 70 days of exposure. The fat body presented the most prominent GST activity especially after 35 days of exposure with 1.6-fold higher than the control group. Exposure also caused an increase in RS levels in the fat body of 1.35-fold and 1.47-fold after 35 and 70 days, respectively and did not affect the activity of the AChE from the head. Our findings support the harmful impact of volatilized VCH inhalation, highlighting the cockroach N.cinerea as a valuable insect model to investigate environmental toxicants.     

Isolation and identification of tiger parvovirus in captive siberian tigers and phylogenetic analysis of VP2 gene

To better understand the prevalence and molecular epidemiology of parvovirus, this study reports the isolation and characterization of a tiger parvovirus (TPV) named CHJL-Siberian Tiger-01/2017 from a captive Siberian tiger in Jilin Province, China. A phylogenetic tree based on the full-length VP2 nucleotide sequence was constructed using the isolated strain in this study and 56 reference strains. The results showed that all the parvoviruses can be grouped into two large branches: the canine parvovirus (CPV) branch and the feline parvovirus (FPV) branch. FPV strains comprised TPVs, FPVs, blue fox parvoviruses (BFPVs), mink enteritis viruses (MEVs), and raccoon feline parvoviruses (RFPVs), and CPV strains comprised CPVs and raccoon dog parvoviruses (RDPVs). RFPVs are also often very closely related to those sampled from other carnivorous species, and raccoons may represent conduits for parvovirus transmission to other hosts. The results of amino acid changes in the VP2 protein of the isolated strain showed that amino acid Ile 101 was mutated to Thr (I 101T). Taken together, a field TPV strain CHJL-Siberian Tiger-01/2017 was isolated, which may be suitable for future studies on FPV infection, replication and vaccine development. This study provided new important findings about the evolution of parvovirus infection in tigers.     

Celastrus orbiculatus Extracts Inhibit Human Hepatocellular Carcinoma Growth by Targeting mTOR Signaling Pathways

Objective: To characterize the molecular mechanism underlying the antineoplastic activity of Celastrus orbiculatus Thunb. extracts(COE). Methods: The human hepatocellular carcinoma HepG2 cells with mammalian target of rapamycin(mT OR) knockdown expressed(HepG 2/mT OR-) were constructed using molecular biological technology. In vitro, the HepG 2/mT OR-cells were treated with COE at various concentrations(10, 20, 40, 80, 160 and 320 μg/mL). Cell viability was determined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assays. According to the half-maximal inhibitory concentration(IC50) value(140 mg/L), the concentrations of COE in the subsequent experiment was set to alleviate cytotoxicity. The HepG 2/mT OR-cells were divided into 5 groups: negative control(untreated), COE treatment groups(40, 80, 120 mg/L COE) and positive control group(cisplatin, DDP, 2 mg/L), respectively. Wild-type HepG 2 cells were used as a blank control. The effects of COE on the cell apoptosis were analyzed by flow cytometry and transmission electronic microscopy(TEM), respectively. The protein expression levels of mT OR signal pathways were determined by Western blotting. In vivo, HepG2/mTOR-cells(2×10~6 cell/mice) were subcutaneously injected into the right flank of nude mice. Thirty-six female nude mice were randomly assigned to 6 groups according to body weight(6 mice per group) as follows: solvent vehicle control, Banmao Capsule treated group(BM, 195 mg/kg), Tegafur, Gimeracil and Oteracil Potassium Capsules(10 mg/kg) treated group, and different dosages of COE(10, 20, 40 mg/kg) groups. Tumor growth was monitored and immunohistochemical staining was used to examine the expression of apoptosis-related proteins in tumor tissues. Results: COE inhibited the proliferation significantly in a concentration-dependent manner in HepG 2/mT OR-cells(P0.01). COE significantly induced the apoptosis of HepG 2/mT OR-cells(P0.01), and the apoptotic bodies can be observed under TEM. COE significantly inhibits the proteins expression of mT ORrelated signal pathways. In vivo, COE significantly inhibited tumor growth in nude mice(P0.01). Moreover, the results showed that COE down-regulated the expression of Bcl-2 and Bcl-xL, and up-regulated the levels of Bax and caspase-3 protein(P0.01). Conclusion: COE was a potential chemotherapeutic drug in HCC treatments via targeting mT OR signal pathway.     

Infusions of Large Synthetic HDL Containing Trimeric apoA-I Stabilize Atherosclerotic Plaques in Hypercholesterolemic Rabbits

BackgroundAmong strategies to reduce the remaining risk of cardiovascular disease, interest has focused on using infusions of synthetic high-density lipoprotein (sHDL).MethodsNew Zealand rabbits underwent a perivascular injury at both carotids and were randomly allocated into 2 protocols: (1) a single-dose study, where rabbits were treated with a single infusion of sHDL containing a trimeric form of human apoA-I (TN-sHDL, 200 mg/kg) or with Placebo; (2) a multiple-dose study, where 4 groups of rabbits were treated 5 times with Placebo or TN-sHDL at different doses (8, 40, 100 mg/kg). Plaque changes were analysed in vivo by intravascular ultrasound. Blood was drawn from rabbits for biochemical analyses and cholesterol efflux capacity evaluation.ResultsIn both protocols, atheroma volume in the Placebo groups increased between the first and the second intravascular ultrasound evaluation. A stabilization or a slight regression was instead observed vs baseline in the TN-sHDL-treated groups (P < 0.005 vs Placebo after infusion). TN-sHDL treatment caused a sharp rise of plasma-free cholesterol levels and a significant increase of total cholesterol efflux capacity. Histologic analysis of carotid plaques showed a reduced macrophage accumulation in TN-sHDL-treated rabbits compared with Placebo (P < 0.05).ConclusionsOur results demonstrate that acute and subacute treatments with TN-sHDL are effective in stabilizing atherosclerotic plaques in a rabbit model. This effect appears to be related to a reduced intraplaque accumulation of inflammatory cells. Besides recent failures in proving its efficacy, sHDL treatment remains a fascinating therapeutic option for the reduction of cardiovascular risk.     

Cost-benefit analysis of a national influenza vaccination program in preventing hospitalisation costs in Australian adults aged 50–64 years old

IntroductionInfluenza causes a significant burden among Australian adults aged 50–64, however, vaccine coverage rates remain suboptimal. The National Immunisation Program (NIP) currently funds influenza vaccinations in this age group only for those at high risk of influenza complications.AimsThe main aim of this study was to determine whether a strategy of expanding the government-funded vaccination program to all adults 50–64 in preventing influenza-related hospitalisations will be cost beneficial to the government.MethodsA cost-benefit analysis from a governmental perspective was performed using parameters informed by publicly available databases and published literature. Costs included cost of vaccinations and general practitioner consultation while benefits included the savings from averted respiratory and acute myocardial infarction (AMI) hospitalisations.ResultsIn the base-case scenario, the proposed policy would prevent 314 influenza/pneumonia, 388 other respiratory and 1482 AMI hospitalisations in a year. The government would save $8.03 million with an incremental benefit-cost ratio of 1.40. Most savings were due to averted AMI hospitalisations. In alternative scenarios cost savings ranged from saving of $31.4 million to additional cost to the government of $15.4 million, with sensitive variation in vaccine administration practices (through general practitioner or pharmacists) and vaccine effectiveness estimates.DiscussionExtension of the NIP to include adults 50–64 years of age is likely to be cost beneficial to the government, although this finding is sensitive to vaccine administration cost, which varies if provided through general practitioners or pharmacists; and to variation in vaccine effectiveness. An increased role of pharmacists in immunisation programs would likely result in cost savings in an expanded adult immunisation program.     

Celastrol inhibits microglial pyroptosis and attenuates inflammatory reaction in acute spinal cord injury rats

Pyroptosis pathway is closely related to inflammation. However, Celastrol effect on pyroptosis pathway after spinal cord injury (SCI) are poorly understood. We studied the anti-inflammatory and neuroprotective effects of Celastrol on acute spinal cord injury in rats, and its anti-inflammatory effects on lipopolysaccharide (LPS)/ATP-induced microgliosis. Our results show that Celastrol can improve the recovery of hindlimb motor function after SCI in Sprague-Dawley (SD) rats, and reduce the cavity area of spinal cord injury along with the neuronal loss. Celastrol simultaneously reduced the activation of microglia (especially M1 microglia) in the spinal cord, inhibited the pyroptosis-related proteins (NLRP3 ASC Caspase-1 GSDMD), reduced the release of TNF-α IL-1β and IL-18 inflammatory factors, and increased the release of IL10 cytokines. In vitro studies showed that Celastrol reduced the toxicity resulting from the administration of LPS with ATP to BV-2 cells, inhibited the pyroptosis-related proteins (NLRP3 Caspase-1 GSDMD), and inhibited the release of corresponding inflammatory factors. Finally, Celastrol can inhibit the expression of NFκB/p-p65 in vitro and in vivo. Our results show that Celastrol can attenuate the inflammatory response of the spinal cord after SCI, which is associated with inhibition of microglial activation and pyroptosis pathway. Further study to explore the use of Celastrol to treat SCI is warranted.     

Evolutionary landscapes of Pseudomonas aeruginosa towards ribosome-targeting antibiotic resistance depend on selection strength

It is generally accepted that antibiotic-resistant mutants are selected in a range of concentrations ranging from the minimum inhibitory concentration (MIC) to the mutant preventive concentration. More recently, it has been found that antibiotic-resistant mutants can also be selected at concentrations below MIC, which expands the conditions where this selection may occur. Using experimental evolution approaches followed by whole-genome sequencing, the current study compares the evolutionary trajectories of Pseudomonas aeruginosa in the presence of tobramycin or tigecycline at lethal and sublethal concentrations. Mutants were selected at sublethal concentrations of tigecycline (1/10 and 1/50 MIC), whereas no mutants were selected in the case of tobramycin, indicating that the width of sub-MIC selective windows is antibiotic-specific. In addition, the patterns of evolution towards tigecycline resistance depend on selection strength. Sublethal concentrations of tigecycline select mutants with lower tigecycline MICs and higher MICs to other antibiotics belonging to different structural families than mutants selected under lethal concentrations. This indicates that the strength of the cross-resistance phenotype associated with tigecycline resistance is decoupled from selection strength. Accurate information on the sublethal selection window for each antibiotic of clinical value, including the phenotypes of cross-resistance of mutants selected at each antibiotic concentration, is needed to understand the role of ecosystems polluted with different antibiotic concentrations in the selection of antibiotic resistance. Integration of this information into clinical and environmental safety controls may help to tackle the problem of antibiotic resistance.     

Protection of White Leghorn chickens by recombinant fowlpox vector vaccine with an updated H5 insert against Mexican H5N2 avian influenza viruses

Despite decades of vaccination, surveillance, and biosecurity measures, H5N2 low pathogenicity avian influenza (LPAI) virus infections continue in Mexico and neighboring countries. One explanation for tenacity of H5N2 LPAI in Mexico is the antigenic divergence of circulating field viruses compared to licensed vaccines due to antigenic drift. Our phylogenetic analysis indicates that the H5N2 LPAI viruses circulating in Mexico and neighboring countries since 1994 have undergone antigenic drift away from vaccine seed strains. Here we evaluated the efficacy of a new recombinant fowlpox virus vector containing an updated H5 insert (rFPV-H5/2016), more relevant to the current strains circulating in Mexico. We tested the vaccine efficacy against a closely related subcluster 4 Mexican H5N2 LPAI (2010 H5/LP) virus and the historic H5N2 HPAI (1995 H5/HP) virus in White Leghorn chickens. The rFPV-H5/2016 vaccine provided hemagglutinin inhibition (HI) titers pre-challenge against viral antigens from both challenge viruses in almost 100% of the immunized birds, with no differences in number of birds seroconverting or HI titers among all tested doses (1.5, 2.0, and 3.1 log₁₀ mean tissue culture infectious doses/bird). The vaccine conferred 100% clinical protection and a significant decrease in oral and cloacal virus shedding from 1995 H5/HP virus challenged birds when compared to the sham controls at all tested doses. Virus shedding titers from vaccinated 2010 H5/LP virus challenged birds significantly decreased compared to sham birds especially at earlier time points. Our results confirm the efficacy of the new rFPV-H5/2016 against antigenic drift of LPAI virus in Mexico and suggest that this vaccine would be a good candidate, likely as a primer in a prime-boost vaccination program.     

BCG-Prime and boost with Esx-5 secretion system deletion mutant leads to better protection against clinical strains of Mycobacterium tuberculosis

Although vaccination with BCG prevents disseminated forms of childhood tuberculosis (TB), it does not protect against pulmonary infection or Mycobacterium tuberculosis (Mtb) transmission. In this study, we generated a complete deletion mutant of the Mtb Esx-5 type VII secretion system (Mtb Δesx-5). Mtb Δesx-5 was highly attenuated and safe in immunocompromised mice. When tested as a vaccine candidate to boost BCG-primed immunity, Mtb Δesx-5 improved protection against highly virulent Mtb strains in the murine and guinea pig models of TB. Enhanced protection provided by heterologous BCG-prime plus Mtb Δesx-5 boost regimen was associated with increased pulmonary influx of central memory T cells (T_CM), follicular helper T cells (T_FH) and activated monocytes. Conversely, lower numbers of T cells expressing exhaustion markers were observed in vaccinated animals. Our results suggest that boosting BCG-primed immunity with Mtb Δesx-5 is a potential approach to improve protective immunity against Mtb. Further insight into the mechanism of action of this novel prime-boost approach is warranted.