New products of nanotechnologies, including nanoparticles, need to be assessed according to their biological reactivity and toxic potential. Given the large number of diverse nanomaterials, a tiered ...approach is favoured. The aim of our work presented here is to elaborate an
in vivo assay with terrestrial invertebrates (
Porcellio scaber), which could serve as a first step of hazard identification of nanoparticles. We adapted the widely used acridine orange/ethidium bromide (AO/EB) assay to be applicable for cell membrane stability assessment of entire organ where the animal was exposed
in vivo. The digestive glands (hepatopancreas) of terrestrial isopods were taken as a model test system. The assay was validated with Cu(NO
3)
2 and surfactants. The results showed that all tested nanoparticles, i.e. nanosized TiO
2, nanosized ZnO and fullerenes (C
60) have cell membrane destabilization potential. As expected, C
60 is the most biologically potent. The AO/EB
in vivo assay proved to be fast because response is recorded after 30
min of exposure, relatively simple because digestive glands are inspected immediately after isolation from exposed animals and promising approach because different types of nanoparticles could be tested for their biological potential. This assay provides data for the identification of hazardous potential of nanoparticles before subsequent steps in a tiered approach are decided.
Superparamagnetic iron oxide nanoparticles (SPIONs) with multifunctional properties have shown great promise in theranostics. The aim of our work was to compare the effects of SPIONs on the fluidity ...and phase transition of the liposomal membranes prepared with zwitterionic phosphatidylcholine lipids. In order to study if the surface modification of SPIONs has any influence on these membrane properties, we have used four types of differently functionalized SPIONs, such as: plain SPIONs (primary size was shown to bê11 nm), silica-coated SPIONs, SPIONs coated with silica and functionalized with positively charged amino groups or negatively charged carboxyl groups (the primary size of all the surface-modified SPIONs was ~20 nm). Small unilamellar vesicles prepared with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine lipids and multilamellar vesicles prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine lipids were encapsulated or incubated with the plain and surface-modified SPIONs to determine the fluidity and phase transition temperature of the bilayer lipids, respectively. Fluorescent anisotropy and differential scanning calorimetric measurements of the liposomes that were either encapsulated or incubated with the suspension of SPIONs did not show a significant difference in the lipid ordering and fluidity; though the encapsulated SPIONs showed a slightly increased effect on the fluidity of the model membranes in comparison with the incubated SPIONs. This indicates the low potential of the SPIONs to interact with the nontargeted cell membranes, which is a desirable factor for in vivo applications.
Imidacloprid is a neonicotinoid insecticide with neurotoxic action that, as a possible alternative for commonly used organophosphorus pesticides, has gained registration in about 120 countries for ...use in over 140 agricultural crops. Only few data are available on its toxicity for soil invertebrates. We therefore assessed the effects of imidacloprid on survival, weight gain, feeding rate, total protein content, glutathione S-transferase activity (GST), and digestive gland epithelial thickness in juveniles and adults of the terrestrial isopod Porcellio scaber. After two weeks of feeding on imidacloprid-dosed food, weight gain (NOEC 5μg/g dry food) and feeding rate (NOEC 10μg/g) in juveniles, and feeding rate (NOEC<10μg/g) and digestive gland epithelial thickness (NOEC<10μg/g) in adults were most affected. In juveniles induction of GST activity and increase of total protein content per wet animal weight was detected at 5μg/g dry food, whereas in adults a reduction of GST was observed at 25μg/g (NOEC 10μg/g). An estimate of actual intake rates suggests that imidacloprid affects isopods at similar exposure concentrations as insects. The toxicity of imidacloprid was similar to that of the organophosphorus pesticide diazinon, tested earlier using the same methods Stanek, K., Drobne, D., Trebse, P., 2006. Linkage of biomarkers along levels of biological complexity in juvenile and adult diazinon fed terrestrial isopod (Porcellio scaber, Isopoda, Crustacea). Chemosphere 64, 1745–1752. At actual environmental concentrations, diazinon poses a higher risk to P. scaber. Due to its increasing use in crop protection and higher persistence in soil, imidacloprid might however, be potentially more dangerous after long-term application. We conclude that toxicity testing with P. scaber provides relevant, repeatable, reproducible and comparable toxicity data that is useful for the risk assessment of pesticides in the terrestrial environment.
Abstract
Background
Vedolizumab (VDZ) is an anti-integrin monoclonal antibody for the treatment of inflammatory bowel disease. There appears to be a positive correlation between drug levels and ...clinical outcomes, however, data on endoscopic outcomes are scarce. We investigated the impact of induction VDZ trough levels (TL) on clinical and endoscopic outcomes in our real-world cohort.
Methods
We prospectively identified all patients treated with VDZ in a tertiary referral hospital: 50 patients (25 Crohn’s disease CD, 25 ulcerative colitis UC), mostly resistant to anti-TNF agents with a mean disease duration of 10 years (SD 7.8). VDZ TL were measured at Weeks 2, 6, 10, and 14 using an in-house developed ELISA assay (KU Leuven, Belgium). The main clinical outcome was a composite of partial (need for dose optimisation to q4 weeks) or complete drug failure (withdrawal of drug due to inefficacy). Thirty patients (13 CD, 17 UC), including all treatment failures, underwent endoscopy between Weeks 30 and 52 to assess for mucosal healing (modified Rutgeerts score <i2b, SES-CD <4; Mayo endoscopic subscore 0/1), evaluated centrally by a blinded endoscopist. Potential independent predictors of clinical (CRP, albumin, disease phenotype, steroid use) and endoscopic outcomes were subjected to univariate analysis and a Cox or logistic regression model respectively. Predictive cut-off values were identified using ROC curve analysis, categoric variables were compared with the χ2 test.
Results
After a median follow-up of 44 weeks (IQR 30) 23 of 50 patients (46%) discontinued treatment or required dose optimisation. The only independent significant predictor were TL at Week 6 (HR 0.54 per 10 µg/ml increase in TL, 95% CI 0.35–0.90; p = 0.02). Patients with TL below the median (18 µg/ml) were more likely to experience drug failure (60% vs. 32%; p = 0.04) (Figure 1). Mucosal healing was achieved by 8 of 30 (27%) patients, again TL at Week 6 were a significant predictor (HR 2.84 per 10 µg/ml increase in TL, 95% CI 1.10–6.19; p = 0.04). Patients with TL above the median (18 µg/ml) were more likely to have mucosal healing (47% vs. 7%; p = 0.01) (Figure 1). A Week 6 TL below 28.2 µg/ml predicted complete or partial drug failure with 81% sensitivity and 70% specificity (AUC = 0.70; p = 0.03), while a Week 6 TL above 33.6 µg/ml predicted mucosal healing with 25% sensitivity and 94% specificity (AUC = 0.80; p = 0.02).
Impact of Week 6 vedolizumab trough levels on clinical and endoscopic outcomes. Clinical failure–drug discontinuation or need for optimisation; mucosal healing–modified Rutgeerts below i2b, SES-CD below 4, Mayo endoscopic subscore 0 or 1.
Conclusions
Vedolizumab trough levels after 6 weeks of treatment independently predicted drug failure and endoscopic remission, highlighting their possible role in future treatment algorithms.
In parallel laboratory experiments, we determined the effect of a typical representative of organophosphorous pesticides, diazinon, on AChE activity, lipid, protein and glycogen content, weight ...change, feeding activity and mortality of juvenile and adult terrestrial isopods
Porcellio scaber (Isopoda, Crustacea). Organophosphorous pesticides (OP) are among the most extensively used pesticides, which have replaced organochlorine pesticides. OPs inhibit the enzyme acetylcholinesterase (AChE), resulting in neurotoxicity. They have more widespread effects on non-target organisms than do organochlorine pesticides. The aim of this study was to link effect of diazinon on target enzyme to energy reserves and to integrated biomarker responses in juvenile and adult
P. scaber. The non-observed effect concentration (NOEC) for AChE activity after diazinon exposure in two weeks toxicity study with isopods was below 5
μg/g diazinon. There was a good agreement between concentrations at which AChE and survival were affected (10
μg/g diazinon in juveniles, 100
μg/g diazinon in adults). We revealed a link among AChE activity, protein content and mortality. Glycogen and lipid content, feeding activity and weight change were not affected in two weeks diazinon exposure up to 100
μg/g diazinon. Juveniles were affected at concentrations that were an order of magnitude lower than those provoking similar effects on adults. Recommendations are made for future toxicity studies with terrestrial isopods.
Abstract
Background
Endoscopic post-operative recurrence (ePOR) is common following ileocecal resection (ICR) in patients with Crohn’s disease (CD), reaching up to, 70% at, 1-year. In clinical ...trials, prophylaxis with anti-TNF therapies demonstrated a decrease in ePOR to around, 20% at, 1-year. Here we aimed to compare the effectiveness of vedolizumab (VDZ) and ustekinumab (UST) to anti-TNFs for preventing ePOR after curative ICR in adults with CD in a real-world setting.
Methods
This was a retrospective multicenter study, assessing patients with CD >17years who underwent ICR between, 2015–2019, started prophylaxis within six months of surgery, and underwent an ileocolonoscopy ≥ four months after prophylaxis. ePOR (Rutgeerts score ≥ i2 or colonic-segmental-SES-CD≥6) was assessed at, 12, 24, 36-months periods post-surgery. Multivariate logistic regression was used to assess risk factors for ePOR, and IPTW was performed to compare the effectiveness between agents.
Results
Included, 297 patients 53.9% males, age-at-diagnosis, 24(19–32) years (median;IQR), age-at-ICR, 34(26–43)years (median;IQR), 18.5% current-smokers. Of these, 17.2% had previous-ICR, 8.1% were biologic naïve, 65.7% anti-TNF experienced, and, 28.6% exposed to, 2 biologics. Overall, 224, 39 and, 34 patients received respectively anti-TNFs, VDZ or UST for prevention of POR. Patients on VDZ and UST were more likely to be biologic experienced or post previous-ICR. ePOR rates for the entire cohort, anti-TNF, VDZ and UST were:, 41.8%, 40.2%, 33%, and, 61.8% at, 12-months, 49.0%, 46.5%, 44.4%, and, 72.4% at, 24- months, and, 48.6%, 47.9%, 44.0% and, 62.5% at, 36-months, respectively. Risk factors for ePOR: past infliximab (Adj.OR =1.73 95% CI:, 1.01–2.97, p=0.045) or adalimumab (Adj.OR = 2.32 95% CI:, 1.35–4.01, p=0.002), and technical aspects of anastomosis. After controlling for the disparities between groups by the IPTW method risk of ePOR at, 12-months was comparable between patients on anti-TNFs vs VDZ or anti-TNFs vs UST. However, comparison between VDZ vs UST groups revealed that patients on UST were at a higher risk for ePOR at, 12-months (OR=3.75 95% CI:, 1.33–10.6), p=0.012.
Conclusion
Prevention of ePOR was successful in ~60% of patients at, 12-months period. Patients on prophylaxis VDZ or UST consisted of a distinct, more refractory group with higher rates of ePOR. Post-operative treatment with UST or VDZ resulted in a similar risk of ePOR when compared to post-operative prophylaxis with anti-TNF after controlling for disease severity.
1 University of Ljubljana, Biotechnical Faculty, Biological Department, Ve na pot 111, 1111 Ljubljana, Slovenia
2 University of Ljubljana, Biotechnical Faculty, Zootechnical Department, Groblje 3, ...1230 Dom ale, Slovenia
Correspondence Gorazd Avgu tin gorazd.avgustin{at}bfro.uni-lj.si
Intracellular bacteria were observed in the hepatopancreas of the terrestrial isopod Porcellio scaber . Comparative 16S rRNA gene sequence analysis and electron microscopic observations were used to determine the taxonomic position of these intracellular bacteria. Phylogenetic analysis and a complex developmental cycle affiliate these bacteria to the order Chlamydiales , within which they form a distinctive lineage, close to the family Simkaniaceae . They share <92 % 16S rRNA gene sequence similarity with their closest relative and <88 % similarity with other members of the order Chlamydiales . A specific signature oligonucleotide sequence was identified and used as a probe, enabling the identification of intracellular bacteria in infected hepatopancreatic tissue. According to the distinctive morphology of their elementary bodies, which are rod-shaped rather than spherical and contain translucent oblong structures, their genomic properties and their crustacean host, the name Candidatus Rhabdochlamydia porcellionis' is proposed for intracellular bacteria in the hepatopancreas of P. scaber .
Abbreviations: ECL, environmental chlamydiae lineage
Published online ahead of print on 7 November 2003 as DOI 10.1099/ijs.0.02802-0.
The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence determined in this study is AY223862 .
Micrographs showing intracellular bacteria in infected hepatopancreatic cells of P. scaber are available as supplementary material in IJSEM Online.
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