Challenge Dose Research Articles

SFTSV Gn-Head mRNA vaccine confers efficient protection against lethal viral challenge.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne virus, causing thrombocytopenia and hemorrhagic fever, with a fatality rate ranging from 12% to 30%. SFTSV possesses Gn and Gc glycoproteins, which are responsible for host cell receptor attachment and membrane fusion, respectively, to infect host cells. We have previously reported a protein subunit vaccine candidate (sGn-H-FT) of the SFTSV soluble Gn head region (sGn-H) fused with self-assembling ferritin (FT) nanoparticles, displaying strong protective immunogenicity. In this study, we present messenger RNA (mRNA) vaccine candidates encoding sGn-H or sGn-H-FT, both of which exhibit potent in vivo immunogenicity and protection capacity. Mice immunized with either sGn-H or sGn-H-FT mRNA lipid nanoparticle (LNP) vaccine produced strong total antibodies and neutralizing antibodies (NAbs) against sGn-H. Importantly, NAb titers remained high for an extended period. Finally, mice immunized with sGn-H or sGn-H-FT mRNA LNP vaccine were fully protected from a lethal dose of SFTSV challenge, showing no fatality. These findings underscore the promise of sGn-H and sGn-H-FT as vaccine antigen candidates capable of providing protective immunity against SFTSV infection.

Development of recombinant subunit vaccine targeting InvH protein of Salmonella Typhimurium and evaluation of its immunoprotective efficacy against salmonellosis.

Salmonella Typhimurium is the most prevalent non-host specific Salmonella serovars and a major concern for both human and animal health systems worldwide contributing to significant economic loss. Type 3 secretion system (T3SS) of Salmonella plays an important role in bacterial adherence and entry into the host epithelial cells. The product of invH gene of Salmonella is an important component of the needle complex of the type 3 secretion system. Hence, the present study was undertaken to clone and express the 15kDa InvH surface protein of Salmonella Typhimurium in an E. coli host and to evaluate its immune potency in mice. The purified recombinant InvH (r-InvH) protein provoked a significant (p < 0.01) rise in IgG in the inoculated mice. The immunized mice were completely (100%) protected against the challenge dose of 107.5 LD50, while protection against challenge with the same dose of heterologous serovars was 90%. The bacterin-vaccinated group showed homologous protection of 60% against all three serovars. Findings in this study suggest the potential of the r-InvH protein of S. Typhimurium as an effective vaccine candidate against Salmonella infections.

Beam mask and sliding window-facilitated deep learning-based accurate and efficient dose prediction for pencil beam scanning proton therapy.

Accurate and efficient dose calculation is essential for on-line adaptive planning in proton therapy. Deep learning (DL) has shown promising dose prediction results in photon therapy. However, there is a scarcity of DL-based dose prediction methods specifically designed for proton therapy. Successful dose prediction method for proton therapy should account for more challenging dose prediction problems in pencil beam scanning proton therapy (PBSPT) due to its sensitivity to heterogeneities. To develop a DL-based PBSPT dose prediction workflow with high accuracy and balanced complexity to support on-line adaptive proton therapy clinical decision and subsequent replanning. PBSPT plans of 103 prostate cancer patients (93 for training and the other 10 for independent testing) and 83 lung cancer patients (73 for training and the other 10 for independent testing) previously treated at our institution were included in the study, each with computed tomography scans (CTs), structure sets, and plan doses calculated by the in-house developed Monte-Carlo dose engine (considered as the ground truth in the model training and testing). For the ablation study, we designed three experiments corresponding to the following three methods: (1) Experiment 1, the conventional region of interest (ROI) (composed of targets and organs-at-risk [OARs]) method. (2) Experiment 2, the beam mask (generated by raytracing of proton beams) method to improve proton dose prediction. (3) Experiment 3, the sliding window method for the model to focus on local details to further improve proton dose prediction. A fully connected 3D-Unet was adopted as the backbone. Dose volume histogram (DVH) indices, 3D Gamma passing rates with a criterion of 3%/3mm/10%, and dice coefficients for the structures enclosed by the iso-dose lines between the predicted and the ground truth doses were used as the evaluation metrics. The calculation time for each proton dose prediction was recorded to evaluate the method's efficiency. Compared to the conventional ROI method, the beam mask method improved the agreement of DVH indices for both targets and OARs and the sliding window method further improved the agreement of the DVH indices (for lung cancer, CTV D98 absolute deviation: 0.74 ± 0.18 vs. 0.57 ± 0.21 vs. 0.54 ± 0.15 Gy[RBE], ROI vs. beam mask vs. sliding window methods, respectively). For the 3D Gamma passing rates in the target, OARs, and BODY (outside target and OARs), the beam mask method improved the passing rates in these regions and the sliding window method further improved them (for prostate cancer, targets: 96.93% ± 0.53% vs. 98.88% ± 0.49% vs. 99.97% ± 0.07%, BODY: 86.88% ± 0.74% vs. 93.21% ± 0.56% vs. 95.17% ± 0.59%). A similar trend was also observed for the dice coefficients. This trend was especially remarkable for relatively low prescription isodose lines (for lung cancer, 10% isodose line dice: 0.871 ± 0.027 vs. 0.911 ± 0.023 vs. 0.927 ± 0.017). The dose predictions for all the testing cases were completed within 0.25s. An accurate and efficient deep learning-augmented proton dose prediction framework has been developed for PBSPT, which can predict accurate dose distributions not only inside but also outside ROI efficiently. The framework can potentially further reduce the initial planning and adaptive replanning workload in PBSPT.

Trimethyltin chloride induces apoptosis and DNA damage via ROS/NF-κB in grass carp liver cells causing immune dysfunction

Trimethyltin chloride (TMT), a common component in fungicides and plastic stabilizers, presents environmental risks, particularly to fish farming. The precise toxicological mechanisms of TMT in L8824 grass carp liver cells remain undefined. Our study investigates TMT's effects on these cells, focusing on its potential to induce hepatotoxicity via oxidative stress and NF-κB pathway activation. First, we selected 0, 3, 6, and 12 μM as the challenge doses, according to the inhibitory concentration of 50% (IC50) of TMT. Our results demonstrate that TMT decreases cell viability dose-dependently and triggers oxidative stress, as evidenced by increased ROS staining and MDA content. Concurrently, it inhibited the antioxidant activities of T-AOC, T-SOD, CAT, and GSH. The activation of the NF-κB pathway was confirmed by gene expression changes. Furthermore, we observed an increase in cell apoptosis rate by AO/EB staining and cell flow cytometry, and the downregulation of Bcl-2 and the upregulation of Bax, Cytc, Caspase-9, and casp3 verified that TMT passed through the BCL2/BAX/casp3 pathway induces apoptosis. DNA damage was validated by the comet assay and γH2AX gene overexpression. Lastly, our data showed increased expression of TNF-α, IL-1β, IL-6, and INF-γ and decreased antimicrobial peptides, validating immune dysfunction. In conclusion, our findings establish that TMT induces apoptosis and DNA damage via ROS/NF-κB in grass carp liver cells, causing immune dysfunction. This study provides novel insights into the toxicology research of TMT and sheds light on the immunological effects of TMT toxicity, enriching our understanding of the immunotoxicity of TMT on aquatic organisms and contributing to the protection of ecosystems.

Utilization of Mating Behavior as a Parameter to Understand Adaptive Response in &lt;i&gt;Drosophila melanogaster&lt;/i&gt; using Ethyl Methanesulfonate and Methyl Methanesulfonate

Monofunctional alkylating agents, Ethyl Methanesulfonate (EMS) and Methyl Methanesulfonate (MMS) were used to understand adaptive response utilising mating behaviour as a parameter in D. melanogaster. Selected conditioning and challenging doses of EMS (0.5mM and 15mM) or MMS (0.1mM and 3mM) by larval feeding were tested employing different combinations of crosses. The results have revealed that both EMS and MMS affected courtship elements significantly in different combinations of crosses. Nonetheless, significant increases in orientation, tapping, wing vibration and licking were observed when both males and females were treated with a challenging dose of MMS compared to EMS (p&lt;0.05). On par with this, were also the results of female rejection elements in both the tested chemicals. When conditioning and challenging doses were given after 2 hours of time lag between them to 48±4h or 72±4h aged larvae of D. melanogaster, the results showed that male and female courtship elements significantly reduced compared to the additive effect of respective agents. Similarly, the courtship latency and copulation latency were significantly decreased in contrast to copulation duration which was significantly increased (p&lt;0.05). Thus the results demonstrate the presence of adaptive response in D. melanogaster using courtship elements and the authors opine that mating behaviour can be used as a parameter to analyze adaptive response in D. melanogaster within a short period of time compared to other test procedures.

FTIR spectroscopic investigations of protein conformation provide clues of radioadaptation in the kidney of low-dose irradiated rats

Proteins comprise almost half of the weight of plasma membrane and are responsible for preforming various membrane functions. Functionality of the protein is sensitive to its structure. Therefore, modification of the protein conformation can abrogate its function. We demonstrate the induction of radioadaptation in the kidney of low-dose irradiated rats in the form of diminishing the alterations of the protein secondary structure. The FTIR amide I absorption band fitting using Lorentz function was used to identify the various components of the protein secondary structure. FTIR data show changes in amide I band position, amide I/amide II area ratio, FWHM of amide I band, the shifts in the β-structure bands at 1611, 1623, 1634 cm−1 and the decrease in the β/α ratio. 2Gy x-irradiation lead to an increase in the β-structure at the expense of the α-helix. The effect of 2Gy x-irradiation was diminished when preceded with 100 mGy x-rays 24 h earlier. The data provide clue of induction of radioadaptation in the kidneys of whole-body irradiated rats following receiving a low priming dose 24 h prior to a challenging dose.

Hallucinogenic activity, neurotransmitters release, anxiolytic and neurotoxic effects in Rat's brain following repeated administration of novel psychoactive compound 25B-NBOMe

2-(4-Bromo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)etanoamine (25B-NBOMe) is a highly selective 5-HT2A receptor agonist, exhibiting a potent hallucinogenic activity. In the present study, we investigated the effect of a 7-day treatment with 25B-NBOMe in a dose of 0.3 mg/kg on the following: the neurotransmitter release in vivo using microdialysis in freely moving animals, hallucinogenic activity measured in the Wet Dog Shake (WDS) test, anxiety level as measured in the light/dark box (LDB) and locomotor activity in the open field (OF) test, DNA damage with the comet assay, and on a number of neuronal and glial cells with immunohistochemistry. Repeated administration of 25B-NBOMe decreased the response to a challenge dose (0.3 mg/kg) on DA, 5-HT and glutamatergic neurons in the rats’ frontal cortex, striatum, and nucleus accumbens. The WDS response dropped drastically after the second day of treatment, suggesting a rapid development of tolerance. LDB and OF tests showed that the effect of 25B-NBOMe on anxiety depends on the treatment and environmental settings. Results obtained with the comet assay indicate a genotoxic properties in the frontal cortex and hippocampus. An increase in immunopositive glial but not neuronal cells was observed in the cortical regions but not in the hippocampus. In conclusion, our study showed that a chronic administration of 25B-NBOMe produces the development of tolerance observed in the neurotransmitters release and hallucinogenic activity. The oxidative damage of cortical and hippocampal DNA implies the generation of free radicals by the drug, resulting in genotoxicity but rather not in neurotoxic tissue damage. Behavioral tests show that 25B-NBOMe exerts anxiogenic effect after single and repeated treatment.

Reducing Campylobacter colonization in broilers by active immunization of naive broiler breeders using a bacterin and subunit vaccine

Campylobacter is the main cause of human gastroenteritis worldwide, with 50 to 80% of the cases related to consumption of poultry products. Maternal antibodies (MAB) from commercial breeder flocks may protect their progeny against infection during the first few weeks of life. We here studied the prevalence of Campylobacter antibody titers in broiler breeder flocks and to which extent immunization of broiler breeders increases maternal anti-Campylobacter titers in their progeny and protects the offspring against Campylobacter colonization. Two vaccines were used: a bacterin mix of 13 Campylobacter strains and a subunit vaccine comprising 6 immunodominant Campylobacter antigens. All sampled on-farm breeder flocks were positive for anti-Campylobacter antibodies, yet in some breeder flocks only very low titers were detected. Vaccination of SPF broiler breeder flocks with both subunit and bacterin vaccines resulted in a prolonged presence of anti-Campylobacter antibodies in the serum and intestinal mucus of chicks. These bacterin- or subunit vaccine-induced MAB conferred protection against Campylobacter colonization in chicks until 7 and 21 d of age, respectively, but only at a low challenge dose (102.5 cfu). The concentration of MAB in the mucus is probably too low to sufficiently capture Campylobacter when higher challenge doses are used. In conclusion, vaccinating broiler breeders protects their offspring against Campylobacter colonization under low pathogen exposure conditions.

Radioadapted Response Early Effects and Late Effects on Survival of White Blood Cells in Mice (Mus musculus L) Post C0-60 Gamma Radiation

Aims: Determine the radioadapted response to the early and late effects of white blood cells in mice after Co-60 gamma radiation. Furthermore, the effect of the radioadapted early and late effects of the radioresponse with the interval dose adaptation (DA) with the challenge dose (DC) to the white blood cells of mice, as well as the survival rate of mice white blood cells after gamma Co-60 radiation through the radio-adapted response of the early effect and the late effect.&#x0D; Place and Duration of Study: The Radioteraphy Installation in Prof. I.G.N.G. NGOERAH Hospital, between from August to October 2022.&#x0D; Methodology: This research used a low-dose method (adapted-DA dose) and at certain time intervals was continued with a larger dose (dose challenge-DC) in mice with six treatments and one as a control. From each treatment, mice's white blood cells were taken to determine the number of leukocytes and their components. Through the number of leukocytes, it is possible to analyze the radio-adaptated response to the early effect and the late effect, so that thesurvival rate of whiteblood cells inmice after gamma Co-60 radiation can be determined.&#x0D; Results: The results of research on the survival of leukocyte cells, neutrophils, and lymphocyte cell components show early-responding tissue and late-responding tissue. As for cell survival, other componentssuch asmonocytes, eosinophils, andbasophils did not respond in the same way after gamma Co-60 radiation. In general, giving a time delay to the challenge dose for all radiation dose treatments gives a fast response (early effect) to cell survival within a few days after radiation, then with time the full response that occurs is a slow (late effect). The longer the delay in giving the challenge dose, the slower the response will fully occur in the tissue after gamma Co-60 radiation. The cell survival curve also shows that the α/β ratio for the early effect is 3 and for the late effect is 10, which is an illustration of the early effect on radiation, with a linear shape of the cell death curve indicating that tissue is more sensitive to changes in radiation dose and has a greater α/β ratio. When compared to the tissue with a late effect on radiation, the tissue has a smaller α/β ratio indicating that the tissue is less sensitive to changes in the timing of the challenge dose.&#x0D; Conclusion: Radioadapted response to the survival of leukocytes, neutrophils cell components, and lymphocytes have shown early responding tissue and late responding tissue after gamma Co-60 radiation. By giving a time lag for the challenge dose, an early response to cell survival occurs for only a few days, then with time, fully the response that occurs is late responding.

Protective Anti-HBs Antibodies and Response to a Booster Dose in Medical Students Vaccinated at Childhood.

The immune system in humans is regulated by the circadian rhythm. Published studies have reported that the time of vaccination is associated with the immune response to vaccine for some pathogens. Our study aimed to evaluate the association between time of dose administration of challenge HBV vaccine and seroconversion for anti-HBs in medical students vaccinated at birth who were found to be unprotected at pre-training screening. Humoral protection for HBV was assessed in 885 medical students vaccinated during childhood. In total, 359 (41.0%) of them showed anti-HBs titer < 10 UI/mL and received a challenge dose of HBV vaccine followed by post-vaccination screening 30-60 days later. The challenge dose elicited a protective immune response (anti-HBs IgG titer > 10 UI/mL) in 295 (83.8%) individuals. Seroconversion was significantly associated with female gender and time of vaccination after controlling for age group and nationality at logistic regression analysis. Students who received the booster dose in the morning had a higher response rate than those who received the vaccine in the afternoon (OR 1.93; 95% C.I. 1.047-3.56: p < 0.05). This finding suggests that morning administration of the HBV booster may result in a better immune response in susceptible individuals.

Establishment of a Nipah Virus Disease Model in Hamsters, including a Comparison of Intranasal and Intraperitoneal Routes of Challenge.

Nipah virus (NiV) is an emerging pathogen that can cause severe respiratory illness and encephalitis in humans. The main reservoir is fruit bats, distributed across a large geographical area that includes Australia, Southeast Asia, and Africa. Incursion into humans is widely reported through exposure of infected pigs, ingestion of contaminated food, or through contact with an infected person. With no approved treatments or vaccines, NiV poses a threat to human public health and has epidemic potential. To aid with the assessment of emerging interventions being developed, an expansion of preclinical testing capability is required. Given variations in the model parameters observed in different sites during establishment, optimisation of challenge routes and doses is required. Upon evaluating the hamster model, an intranasal route of challenge was compared with intraperitoneal delivery, demonstrating a more rapid dissemination to wider tissues in the latter. A dose effect was observed between those causing respiratory illness and those resulting in neurological disease. The data demonstrate the successful establishment of the hamster model of NiV disease for subsequent use in the evaluation of vaccines and antivirals.

Limited Benefit of Postexposure Prophylaxis With VSV-EBOV in Ebola Virus-Infected Rhesus Macaques.

Vesicular stomatitis virus-Ebola virus (VSV-EBOV) vaccine has been successfully used in ring vaccination approaches during EBOV disease outbreaks demonstrating its general benefit in short-term prophylactic vaccination, but actual proof of its benefit in true postexposure prophylaxis (PEP) for humans is missing. Animal studies have indicated PEP efficacy when VSV-EBOV was used within hours of lethal EBOV challenge. Here, we used a lower EBOV challenge dose and a combined intravenous and intramuscular VSV-EBOV administration to improve PEP efficacy in the rhesus macaque model. VSV-EBOV treatment 1 hour after EBOV challenge resulted in delayed disease progression but little benefit in outcome. Thus, we could not confirm previous results indicating questionable benefit of VSV-EBOV for EBOV PEP in a nonhuman primate model.

The Aqueous Lyophilisate of Alchemilla Kiwuensis Engl. (Rosaceae) Displays Antiepileptogenic and Antiepileptic Effects on PTZ-induced Kindling in rats: Evidence of Modulation of Glutamatergic and GABAergic Pathways Coupled to Antioxidant Properties.

Alchemilla kiwuensis Engl. (Rosaceae) (A. kiwuensis) is an herbaceous plant traditionally used by Cameroonians to treat epilepsy and other central nervous system disorders. The present study evaluated the antiepileptogenic and antiepileptic effects of A. kiwuensis (40mg/kg, 80mg/kg) following Pentylenetetrazole (PTZ)-induced kindling as well as its sub-chronic toxicity. Following an initial i.p administration of a challenge dose (70mg/kg), Wistar rats of both sexes received sub convulsive doses (35mg/kg) of PTZ every other day, one hour after the oral gavage of animals with treatments, until two consecutive stage 4, in all animals of negative control. Seizure progression, latency, duration, and repetition were noted. Twenty-four hours later, animals were dissected to extract their hippocampi. The resulting homogenates were used to evaluate Malondialdehyde, reduced glutathione, catalase activity, GABA, GABA-Transaminase, glutamate, glutamate transporter 2, IL-1β and TGF-1 β. Sub-chronic toxicity was conducted according to OECD 407 guidelines. The lyophilisate of A. kiwuensis significantly increased the latency of seizure appearance, delayed seizure progression and decreased seizure repetition and duration. Biochemical analysis revealed that the lyophilisate significantly increased the catalase activity, reduced glutathione, GABA, glutamate transporter 2 and TGF-1B levels. The lyophilisate equally caused a significant decreased in the GABA-Transaminase activity, malondialdehyde, and IL-1 β levels. There was no noticeable sign of toxicity. A. kiwuensis possesses antiepileptic and antiepiletogenic effects by enhancing GABAergic neurotransmission and antioxidant properties, coupled to modulation of glutamatergic and neuroinflammatory pathways and is innocuous in a sub-chronic model. These justifies its local use for the treatment of epilepsy.

Protective antigen of Bacillus anthracis in combination with TLR4 or TLR5 agonist confers superior protection against lethal challenge in mouse model

The immunogenicity and protective ability of recombinant PA (rPA) with two innate immune system modulators, i.e., monophosphoryl lipid A (MPLA), a TLR4 agonist, and recombinant flagellin C (FliC), a TLR5 agonist, were studied in the mouse model. BALB/c mice were inoculated with three doses of rPA + alum (Alum group), rPA + FliC + alum (FliC group), rPA + MPLA + alum (MPLA group), or only alum adjuvant (Alum alone group). Significant increases in anti-PA IgG titers were observed in the Alum, FliC and MPLA groups when compared to control Alum alone group. Similarly, a significant enhancement of proinflammatory (TNF-α, IL-1β), Th1 (IFN-γ, IL-12(p70), IL-2) and Th2 (IL-10, IL-4) cytokines were also noticed in Alum, FliC and MPLA groups compared to Alum alone group. The rPA-specific IgG and cytokine responses in MPLA and FliC groups were significantly higher than the Alum group, suggesting enhancement of immune response by these TLR agonists. MPLA was also found to skew the IgG1:IgG2a ratio towards IgG2a. At a challenge dose of 25 LD50, complete protection was observed in mice of MPLA group whereas lesser protection was observed in FliC (87%) and Alum (50%) groups. Therefore, we suggest the use of MPLA in further development of rPA based anthrax vaccines.

The 5-HT7 receptors in the VLO contribute to the development of morphine-induced behavioral sensitization in rats

The 5-hydroxytryptamine 7 receptor (5-HT7R) is one of the most recently cloned serotonin receptors which have been implicated in many physiological and pathological processes including drug addiction. Behavioral sensitization is the progressive process during which re-exposure to drugs intensified the behavioral and neurochemical responses to drugs. Our previous study has demonstrated that the ventrolateral orbital cortex (VLO) is critical for morphine-induced reinforcing effect. The aim of the present study was to investigate the effect of 5-HT7Rs in the VLO on morphine-induced behavioral sensitization and their underlying molecular mechanisms. Our results showed that a single injection of morphine, followed by a low challenge dose could induce behavioral sensitization. Microinjection of the selective 5-HT7R agonist AS-19 into the VLO during the development phase significantly increased morphine-induced hyperactivity. Microinjection of the 5-HT7R antagonist SB-269970 suppressed acute morphine-induced hyperactivity and the induction of behavioral sensitization, but had no effect on the expression of behavioral sensitization. In addition, the phosphorylation of AKT (Ser 473) was increased during the expression phase of morphine-induced behavioral sensitization. Suppression of the induction phase could also block the increase of p-AKT (Ser 473). In conclusion, we demonstrated that 5-HT7Rs and p-AKT in the VLO at least partially contribute to morphine-induced behavioral sensitization.

The anxiolytic and antidepressant effect of Stachys Lavandulifolia in the experimental pentylenetetrazole-induced rat model of acute seizure

Objective: In traditional medicine, Stachys lavandulifolia or mountain tea has been used in the treatment of arthritis and rheumatoid arthritis. A leaf extract from this plant is also thought to be effective in treating epilepsy as well as other neurological ailments. To assess the effect of S. lavandulifolia extract (SLE), rats were exposed to a stress and anxiety model caused by seizures. Materials and Methods: A challenge dose of pentylenetetrazole (PTZ) (60 mg/kg) was used to induce seizures in male Wistar rats (200–250 g). Animal treated with an intraperitoneal injection of either SLE (50 mg/kg) or sodium valproate (100 mg/kg) alone or in combination 30 min before PTZ challenge. The effect of stress and anxiety was assessed using an open field test (OFT), forced swim test (FST), and elevated plus maze (EPM). At the end of the experiment, anesthesia was used to euthanize rats, and their blood serum was collected for measurements of glutathione (GSH), malondialdehyde (MDA), and GSH peroxidase (GPx). Results: In contrast to the control group, those treated with PTZ exhibited depressive behavior. At 50 mg/kg, SLE provided protection against seizures induced by PTZ. SLE also reduced seizure-induced stress and anxiety, significantly improving FST, EPM, and OFT compared with the PTZ-treated group. By decreasing MDA levels and restoring the antioxidant enzymes GSH and GPx, SLE treatment protects against seizure-induced anxiety and stress. Conclusions: SLE inhibits oxidative stress damage and seizure-induced stress by inhibiting seizures' inhibitory effects.

Glyphosate induces autophagy in hepatic L8824 cell line through NO-mediated activation of RAS/RAF/MEK/ERK signaling pathway and energy metabolism disorders

Glyphosate is an herbicide commonly used worldwide, and its substantial use causes widespread pollution with runoff. However, research on glyphosate toxicity has mostly remained at the embryonic level and existing studies are limited. In the present study, we investigated whether glyphosate can induce autophagy in hepatic L8824cells by regulating energy metabolism and rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated extracellular signal-regulated kinase (MEK)/extracellular regulated protein kinases (ERK) signaling by activating nitric oxide (NO). First, we selected 0, 50, 200, and 500μg/mL as the challenge doses, according to the inhibitory concentration of 50% (IC50) of glyphosate. The results showed that glyphosate exposure increased the enzyme activity of inducible nitric oxide synthase (iNOS), which in turn increased the NO content. The activity and expression of enzymes related to energy metabolism, such as hexokinase (HK)1, HK2, phosphofructokinase (PFK), phosphokinase (PK), succinate dehydrogenase (SDH), and nicotinamide adenine dinucleotide with hydrogen (NADH), were inhibited, and the RAS/RAF/MEK/ERK signaling pathway was activated. This led to the negative expression of mammalian target of rapamycin (mTOR) and P62 in hepatic L8824cells and the activation of the autophagy marker genes microtubule-associated proteins light chain 3 (LC3) and Beclin1 to induce autophagy. The above results were dependent on glyphosate concentration. To verify whether autophagy can be excited by the RAS/RAF/MEK/ERK signaling pathway, we treated L8824cells with the ERK inhibitor U0126 and found that the autophagy gene LC3 was reduced due to the inhibition of ERK, thus demonstrating the reliability of the results. In conclusion, our results demonstrate that glyphosate can induce autophagy in hepatic L8824cells by activating NO, thus regulating energy metabolism and the RAS/RAF/MEK/ERK signaling pathway.

Attenuated Mycobacterium tuberculosis vaccine protection in a low-dose murine challenge model

Bacillus Calmette-Guérin (BCG) remains the only approved tuberculosis (TB) vaccine despite limited efficacy. Preclinical studies of next-generation TB vaccines typically use a murine aerosol model with a supraphysiologic challenge dose. Here, we show that the protective efficacy of a live attenuated Mycobacterium tuberculosis (Mtb) vaccine ΔLprG markedly exceeds that of BCG in a low-dose murine aerosol challenge model. BCG reduced bacterial loads but did not prevent establishment or dissemination of infection in this model. In contrast, ΔLprG prevented detectable infection in 61% of mice and resulted in anatomic containment of 100% breakthrough infections to a single lung. Protection was partially abrogated in a repeated low-dose challenge model, which showed serum IL-17A, IL-6, CXCL2, CCL2, IFN-γ, and CXCL1 as correlates of protection. These data demonstrate that ΔLprG provides increased protection compared to BCG, including reduced detectable infection and anatomic containment, in a low-dose murine challenge model.

Evaluation of micronuclei and antioxidant status in hospital radiation workers occupationally exposed to low-dose ionizing radiation

PurposeThere is scientific evidence that ionizing radiation (IR) can be responsible for various health hazards that are one of the concerns in occupational exposure. This study was performed to evaluate DNA damage and antioxidant status in hospital workers who are occupationally exposed to low doses of IR.Materials and methodsIn this study, twenty occupationally exposed to low doses of IR (CT and angiography) comprising with control groups which matched them. In order to investigate the effects of chronic irradiation of radiation workers, Micronuclei (MN) frequency and the antioxidant activity of Superoxide Dismutase (SOD), Catalase (CAT) and Total Antioxidant Capacity (TAC) were measured. Then, to check adaptation against high challenge dose, the samples (in all groups) were irradiated in vitro and MN frequency was compared. Finally, to investigated the effect of the high dose after the acute and chronic low dose of ionizing radiation, MN frequency was compared in two groups (the control group that was to in-vitro irradiated (acute low dose + high dose) and radiation workers (chronic low dose + high dose)).ResultsMN frequency in the occupationally exposed group (n = 30) increased significantly when compared to the control group (p-value < 0.0001). However, chronic irradiation of radiation workers could not lead to an adaptive Sresponse, while acute low-doses could produce this effect (p-value ˂ 0.05). In addition, the activity levels of antioxidant enzymes SOD, CAT, and TAC were not statistically different between the radiation workers and the control group (p-value > 0.05).ConclusionsWe observed that exposure to low doses of IR leads to increased cytogenetic damage, could not cause an adaptive-response, and improve antioxidant capacity in radiation workers. Controlling healthcare workers' exposure is the first step to improving the health of hospital workers and the quality of patient care, thus decreasing human and economic costs.

The L-arginine-NO-cGMP pathway mediates the locomotor activity alterations during the expression of sensitization to mephedrone in mice.

Mephedrone is a representative of synthetic cathinones that is known from its rewarding and psychostimulant effects. It exerts behavioural sensitization after repeated and then interrupted administration. In our study, we investigated a role of the L-arginine-NO-cGMP-dependent signalling in the expression of sensitization to hyperlocomotion evoked by mephedrone. The study was carried out in male albino Swiss mice. The tested mice received mephedrone (2.5 mg/kg) for 5 consecutive days and on the 20th day of the experiment (the 'challenge' day) animals received both mephedrone (2.5 mg/kg) and a given substance that affects the L-arginine-NO-cGMP signalling, that is, L-arginine hydrochloride (125 or 250 mg/kg), 7-nitroindazole (10 or 20 mg/kg), L-NAME (25 or 50 mg/kg) or methylene blue (5 or 10 mg/kg). We observed that 7-nitroindazole, L-NAME and methylene blue inhibited the expression of sensitization to the mephedrone-induced hyperlocomotion. Moreover, we demonstrated that the mephedrone-induced sensitization is accompanied by lowered levels of D1 receptors and NR2B subunits in the hippocampus, whereas a concurrent administration of L-arginine hydrochloride, 7-nitroindazole and L-NAME with the mephedrone challenge dose reversed these effects. Methylene blue only reversed the mephedrone-induced effects on hippocampal levels of the NR2B subunit. Our study confirms that the L-arginine-NO-cGMP pathway contributes to mechanisms underlying the expression of sensitization to the mephedrone-evoked hyperlocomotion.