Dose-dependent Behavior Research Articles

ESR response of soda–lime glasses irradiated with gamma radiation in the 0.5–20.0 Gy range

ABSTRACTESR readout improvement of gamma-irradiated soda–lime glasses is presented by considering the dose-dependent differences in temperature behaviour of the radiation-induced signal and background signal, and effective difference in g-values of those two signals. Our experimental results demonstrate that the dose-dependent temperature behaviour can improve the ESR signal response for 30–80% in the dose range below 20 Gy by detection at 200 K compared to the room temperature signal readout. The application of improvement can be expected in the low-level dose range where the radiation-induced signal is comparable with an inhomogeneous background signal.

Wound healing-promoting effects stimulated by extracellular calcium and calcium-releasing nanoparticles on dermal fibroblasts

Extracellular calcium has been proved to influence the healing process of injuries and could be used as a novel therapy for skin wound healing. However, a better understanding of its effect, together with a system to obtain a controlled release is needed. In this study, we examined whether the ionic dissolution of the calcium–phosphate-based ormoglass nanoparticles coded SG5 may produce a similar stimulating effect as extracellular calcium (from CaCl2) on rat dermal fibroblast in vitro. Cells were cultured in the presence of medium containing different calcium concentrations, normally ranging from 0.1 to 3.5 mM Ca2+. A concentration of 3.5 mM of CaCl2 increased metabolic activity, in vitro wound closure, matrix metalloproteinases (MMP) activity, collagen synthesis and cytokine expression, and reduced cell contraction capacity. Interestingly, the levels of migration and contraction capacity measured followed a dose-dependent behavior. In addition, media conditioned with SG5 stimulated the same activities as media conditioned with CaCl2, but undesired effects in chronic wound healing such as inflammatory factor expression and MMP activity were reduced compared to the equivalent CaCl2 concentration. In summary, calcium-releasing particles such as SG5 are potential biological-free biostimulators to be applied in dressings for chronic wound healing.

Abstract LB-299: Cynomolgus monkey plasma cell gene signature to quantify the in vivo activity of a half-life extended anti-BCMA BiTE® for the treatment of multiple myeloma

Abstract Background: Multiple myeloma (MM) is a hematologic malignancy where abnormal plasma cells (PC) accumulate in the bone marrow (BM). Patients often develop relapsed/refractory disease leading to significant morbidity and mortality. Elimination of residual disease is required for curative treatments. Patient outcome can be improved by using T-cell engaging agents, such as bispecific T-cell engager (BiTE®) antibody constructs, to redirect T cells to tumor cells. B-cell maturation antigen (BCMA), a TNF receptor superfamily member, supports PC survival and is widely expressed on MM and normal PC. Methods: A half-life extended (HLE) anti-BCMA BiTE® (BCMA HLE-BiTE®) antibody construct was generated and characterized in vitro, and in vivo in a mouse xenograft model and in non-human primates (NHP). To quantify on-target activity of the BCMA HLE-BiTE® in NHP it was necessary to follow changes in PC numbers. Because PC are rare (0.1 - 3%) in the BM and blood, detection using traditional assays is not possible. To address this limitation, a PC gene signature was defined and used to develop a quantitative ddPCR assay (sensitivity = 0.01%) to assess the effect of the BCMA HLE-BiTE® in a 12-day repeat-dose NHP study. Results: A BCMA HLE-BiTE® was selected that demonstrated cytotoxic activity using human effector cells (EC50: 0.13 ± 0.07 pM in MM.1R cells) and comparable activity using NHP effector cells. In a sub-cutaneous mouse xenograft model in which BCMA-positive NCI-H929 cells and human PBMC were co-administered, the BCMA HLE-BiTE® completely inhibited tumor formation, in contrast to vehicle controls with/without PBMC. The serum half-life of the BCMA HLE-BiTE® in NHP was 112 hours following a single 15 µg/kg IV dose. The PK/PD relationship in NHP was next evaluated in a 12-day repeat-dose study. A dose-dependent PK behavior as well as depletion of PC in blood and BM was observed, reaching 93% depletion in the blood and 85% in the BM in the high-dose group on day 12. Conclusions: These results demonstrate that the BCMA HLE-BiTE® is potent and effective at inducing cytotoxicity of target cells in vitro and in vivo, and may be suitable for once-weekly dosing in MM patients. This molecule is being evaluated in humans: trial NCT03287908. Citation Format: Ana Goyos, Chi-Ming Li, Petra Deegen, Pamela Bogner, Oliver Thomas, Joachim Wahl, Rebecca Goldstein, Maththias Friedrich, Angela Coxon, Mercedesz Balazs, Tara Arvedson. Cynomolgus monkey plasma cell gene signature to quantify the in vivo activity of a half-life extended anti-BCMA BiTE® for the treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-299.

Towards direct measurement of electrons in metastable states in K-feldspar: Do infrared-photoluminescence and radioluminescence probe the same trap?

Prasad et al. (2017) recently developed a new method of measuring the dosimetric signal in feldspar, based on a Stokes-shifted photoluminescence emission (excitation energy ∼1.40eV (885 nm), emission energy∼1.30eV (955 nm)). The new signal, termed as infrared photoluminescence (IRPL), was shown to arise from radiative relaxation of the excited state of the principle trap (dosimetric trap), and allows non-destructive probing of the dosimetric information. Thus, IRPL provides a unique tool to study physical characteristics of these metastable states in feldspar, e.g., number density and spatial distribution, trap depth, photo-ionisation and capture cross-section, excited state lifetime, and tunneling probabilities. The IRPL emission is apparently related to the infrared radioluminescence (IR-RL) in K-feldspar (Trautmann et al., 1998); in the latter, however, the electrons relax after being trapped as a result of exposure to ionising radiation, rather than as a result of excitation within the trap.In this study, we report the discovery of a second IRPL emission centred at ∼1.41eV (880 nm) in a K-feldspar which arises in response to excitation with 1.49eV photons. Based on the temperature- and dose-dependent behaviour of IRPL and IR-RL, we conclude that the same defect(s) participates in these two emissions. However, IRPL emission is governed by the characteristics of the principle trap (defect) alone, whereas IR-RL depends additionally on thermally assisted transport within the band-tail states. Since IRPL is a site selective technique, it does not, unlike IR-RL, suffer from contamination from higher energy emissions (e.g. from Fe3+). This lack of contamination, and the possibility for thermal/optical pre-treatments and repeated measurements of the same trapped electrons, suggest that IRPL is a robust alternative to IR-RL.

In vivo antigenotoxic activity of Diplotaxis tenuifolia against cyclophosphamide-induced DNA damage: Relevance of modulation of hepatic ABC efflux transporters

Several epidemiological studies have demonstrated that a diet with high contents of cruciferous vegetables (which belong to the Brassicaceae family) may reduce the incidence of cancer and neurodegenerative diseases. However, some authors have postulated that they might bring about toxic effects. Therefore, the aim of this study was to assess the effects of chronic administration of Diplotaxis tenuifolia (wild rocket), a species found in Argentina, concerning its putative genotoxicity or antigenotoxicity against the DNA damage inducer cyclophosphamide, and its ability to modulate the hepatic expression of ABC efflux transporters on mice. The alkaline comet assay and the micronucleus test were used as genotoxicity biomarkers, and the ABC transporter expression was analyzed by Western-blotting. D. tenuifolia juice exhibited no genotoxicity in any of the three tested doses (p > 0.05), showing instead a protective effect against genotoxic damage induced by cyclophosphamide (p < 0.001) in a dose-dependent behavior. Furthermore, hepatic expression of ABCB1 remained unchanged in both sexes at every dose, whereas ABCG2 expression increased in females (p < 0.05) and males (p < 0.01) at the highest dose. Regarding ABCC2, sex-related differences were observed (p < 0.05), its expression decreasing in females (p < 0.05) and increasing in males (p < 0.05). The modulation of these transporters may contribute to the antigenotoxic effects of D. tenuifolia since they act as universal detoxifiers, excreting xenobiotics to the cellular exterior. Phytochemicals present in the juice such as glucosinolates, quercetin and kaempherol may be responsible for these beneficial effects.

Protease activated receptor 2 (PAR2) activation causes migraine-like pain behaviors in mice.

Pain is the most debilitating symptom of migraine. The cause of migraine pain likely requires activation of meningeal nociceptors. Mast cell degranulation, with subsequent meningeal nociceptor activation, has been implicated in migraine pathophysiology. Degranulating mast cells release serine proteases that can cleave and activate protease activated receptors. The purpose of these studies was to investigate whether protease activated receptor 2 is a potential generator of nociceptive input from the meninges by using selective pharmacological agents and knockout mice. Ratiometric Ca++ imaging was performed on primary trigeminal and dural cell cultures after application of 2at-LIGRL-NH2, a specific protease activated receptor 2 agonist. Cutaneous hypersensitivity and facial grimace was measured in wild-type and protease activated receptor 2-/- mice after dural application of 2at-LIGRL-NH2 or compound 48-80, a mast cell degranulator. Behavioral experiments were also conducted in mice after dural application of 2at-LIGRL-NH2 (2AT) in the presence of either C391, a selective protease activated receptor 2 antagonist, or sumatriptan. 2at-LIGRL-NH2 evoked Ca2+ signaling in mouse trigeminal neurons, dural fibroblasts and in meningeal afferents. Dural application of 2at-LIGRL-NH2 or 48-80 caused dose-dependent grimace behavior and mechanical allodynia that were attenuated by either local or systemic application of C391 as well as in protease activated receptor 2-/- mice. Nociceptive behavior after dural injection of 2at-LIGRL-NH2 was also attenuated by sumatriptan. Functional protease activated receptor 2 receptors are expressed on both dural afferents and fibroblasts and activation of dural protease activated receptor 2 produces migraine-like behavioral responses. Protease activated receptor 2 may link resident immune cells to meningeal nociceptor activation, driving migraine-like pain and implicating protease activated receptor 2 as a therapeutic target for migraine in humans.

Edible seaweeds’ phlorotannins in allergy: A natural multi-target approach

The anti-allergenicity of phlorotannin-targeted extracts from four edible seaweed species of Fucus genus was evaluated herein for the first time. Extracts were able to act upon cellular events triggered by immunological reaction (IgE/antigen), and on cellular events downstream the Ca2+ influx caused by a chemical stimulus (calcium ionophore A23187), preventing degranulation of RBL-2H3 cells. Furthermore, a dose-dependent behaviour towards allergy-related enzymatic systems was observed for all the phlorotannin extracts. Linear correlations were found between reduction of the allergic mediators released and the total phlorotannin content, as well as between the enzyme inhibition and the amount of phlorotannins in the extracts. These results point to a multi-target anti-allergic capacity of phlorotannin-targeted extracts, which displayed effects on different critical steps of the allergic response, contributing to the valorisation of Fucus spp. both as food and for nutraceutical applications.

Corticosterone Signaling and a Lateral Habenula-Ventral Tegmental Area Circuit Modulate Compulsive Self-Injurious Behavior in a Rat Model.

Self-injurious behavior (SIB) is commonly observed in patients with neuropsychiatric disorders, as well as in nonclinical populations with stress-related mental-health problems. However, the exact circuitry mechanisms underlying SIB have remained poorly understood. Here, with bilateral injection of muscimol into the entopeduncular nucleus (EP), we established a rat model of SIB. Following the muscimol injection, the male rats exhibited in a dose-dependent manner stereotypic self-biting behavior that lasted for hours and often resulted in wounds of various severities. The SIB was associated with an elevated level of serum corticosterone and could be exacerbated by enhancing the corticosterone signaling and, conversely, alleviated by inhibiting the corticosterone signaling. Activity mapping using c-fos immunostaining, combined with connectivity mapping using herpes simplex virus-based anterograde tracing from the EP and pseudorabies virus-based retrograde tracing from the masseter muscle, revealed the potential involvement of many brain areas in SIB. In particular, the lateral habenula (LHb) and the ventral tegmental area (VTA), the two connected brain areas involved in stress response and reward processing, showed a significant increase in neuronal activation during SIB. Furthermore, suppressing the LHb activity or modulating the GABAergic transmission in the VTA could significantly reduce the occurrence of SIB. These results demonstrate the importance of stress hormone signaling and the LHb-VTA circuit in modulating SIB resulting from EP malfunction, and suggest potential targets for therapeutic intervention of SIB and related disorders.SIGNIFICANCE STATEMENT Self-injurious behavior (SIB) occurs in ∼4% of the general population, with substantially higher occurrence among adolescents and patients of neuropsychiatric disorders. Stress has been linked to the occurrence of SIB, yet the underlying mechanisms have remained unclear. Using a rat model of SIB induced by disruption of activity in the entopeduncular nucleus (EP), we found that the behavior is regulated by stress and linked to corticosterone signaling. Viral tracing and c-fos immunostaining revealed the involvement of various subcortical areas, especially the EP-lateral habenula (LHb)-ventral tegmental area (VTA) circuit, in SIB. Furthermore, regulating activity in the LHb or the VTA alleviates SIB. These results may have implications in the development of new strategies for treating SIB.

Physicochemical screening for chemical stabilizer of erythropoietin to prevent its aggregation

ABSTRACTRecombinant protein aggregation is a problematic issue and can provoke immunological response. The aim of this study was to analyze the stability of erythropoietin (EPO), as a therapeutic protein expressed in mammalian cells, in the presence of different chemicals and find a specific stabilizer for EPO. The effects of several chemicals, including mannitol, betaine, trehalose, taurine, linoleic acid, beta-cyclodextrin, copper sulfate, spermidine, maltose, maltodextrin, sucrose, dextran, beta-alanine, myo-inositol, and cysteine, on protein stabilization through the thermally induced aggregation of EPO were monitored. Based on the results of turbidity assay for thermal aggregation, three different patterns were observed for protein stability of active pharmaceutical ingredient of EPO, namely, accelerated, dose-dependent, and inhibitory behaviors for aggregate formation due to treatment with spermidine, mannitol, and betaine, respectively. According to circular dichroism outcomes, EPO treatment with betaine and spermidine resulted in different helical contents of the secondary structure. Dynamic light scattering experiments indicated that treating EPO with betaine resulted in less protein aggregation due to freeze and thaw stresses. Betaine was able to stabilize EPO and inhibit its aggregation, as opposed to spermidine that induced protein aggregation.

New adaptive statistical iterative reconstruction ASiR-V: Assessment of noise performance in comparison to ASiR.

PurposeTo assess the noise characteristics of the new adaptive statistical iterative reconstruction (ASiR‐V) in comparison to ASiR.MethodsA water phantom was acquired with common clinical scanning parameters, at five different levels of CTDIvol. Images were reconstructed with different kernels (STD, SOFT, and BONE), different IR levels (40%, 60%, and 100%) and different slice thickness (ST) (0.625 and 2.5 mm), both for ASiR‐V and ASiR. Noise properties were investigated and noise power spectrum (NPS) was evaluated.ResultsASiR‐V significantly reduced noise relative to FBP: noise reduction was in the range 23%–60% for a 0.625 mm ST and 12%–64% for the 2.5 mm ST. Above 2 mGy, noise reduction for ASiR‐V had no dependence on dose. Noise reduction for ASIR‐V has dependence on ST, being greater for STD and SOFT kernels at 2.5 mm. For the STD kernel ASiR‐V has greater noise reduction for both ST, if compared to ASiR. For the SOFT kernel, results varies according to dose and ST, while for BONE kernel ASIR‐V shows less noise reduction. NPS for CT Revolution has dose dependent behavior at lower doses. NPS for ASIR‐V and ASiR is similar, showing a shift toward lower frequencies as the IR level increases for STD and SOFT kernels. The NPS is different between ASiR‐V and ASIR with BONE kernel. NPS for ASiR‐V appears to be ST dependent, having a shift toward lower frequencies for 2.5 mm ST.ConclusionsASiR‐V showed greater noise reduction than ASiR for STD and SOFT kernels, while keeping the same NPS. For the BONE kernel, ASiR‐V presents a completely different behavior, with less noise reduction and modified NPS. Noise properties of the ASiR‐V are dependent on reconstruction slice thickness. The noise properties of ASiR‐V suggest the need for further measurements and efforts to establish new CT protocols to optimize clinical imaging.

Preclinical longitudinal imaging of tumor microvascular radiobiological response with functional optical coherence tomography

Radiation therapy (RT) is widely used for cancer treatment, alone or in combination with other therapies. Recent RT advances have revived interest in delivering higher dose in fewer fractions, which may invoke both cellular and microvascular damage mechanisms. Microvasculature may thus be a potentially sensitive functional biomarker of RT early response, especially for such emerging RT treatments. However it is difficult to measure directly and non-invasively, and its time course, dose dependencies, and overall importance in tumor control are unclear. We use functional optical coherence tomography for quantitative longitudinal in vivo imaging in preclinical models of human tumor xenografts subjected to 10, 20 and 30 Gy doses, furnishing a detailed assessment of vascular remodeling following RT. Immediate (minutes to tens of minutes) and early (days to weeks) RT responses of microvascular supply, as well as tumor volume and fluorescence intensity, were quantified and demonstrated robust and complex temporal dose-dependent behaviors. The findings were compared to theoretical models proposed in the literature.

Acute and sub-acute oral toxicity studies of the aqueous extract from radix, radix with cortex and cortex of Psammosilene tunicoides in mice and rats

Ethnopharmacological relevancePsammosilene tunicoides is one of the important ingredients of a famous Chinese traditional medicine formulation “Yunnan Baiyao”. Also, this plant is commonly used as an anodyne and hemostatic agent in southwest China. Currently, little toxicological information is available on its safety following prolonged use. Aim of the studyIn this study, we sought to evaluate the toxicity of the three different parts of Psammosilene tunicoides: Psammosilenes Radix (PR), Psammosilenes Radix with Cortex (PRC) and Psammosilenes Cortex (PC) by acute and sub-acute toxicity studies. Materials and methodsIn the acute toxicity study, mice were orally administrated with different doses of PR, PRC and PC. General behavior and mortality were observed up to 14 days. In sub-acute toxicity study, these aqueous extracts were given orally as a single administration to rats at doses of 0.3, 0.6 and 1.2g/kg/day, respectively, for 28 days. General behavior, body weight, biochemical, hematological, organ coefficients and pathological morphology parameters were detected. ResultsIn acute study, single oral administration of the aqueous extract of PR, PRC and PC caused dose-dependent general behavior adverse effects and mortality. The LD50 values of PR, PRC and PC were 4.64g/kg, 4.85g/kg and 6.40g/kg, respectively. In sub-acute study, the administration of the extract of PR, PRC and PC during 28 days at all doses reduced spontaneous activities with both genders. Occasional nasal secretion with blood at high doses (1.2g/kg) of PR, PRC and PC were observed. Daily single oral administration provoked varying degrees of growth retardation in female rats. The relative heart and spleen weight in the female rats were reduced after the administration. On the hematological and biochemical analyses, the administration of the extract of PR, PRC and PC during 28 days mainly caused variation of indexes in female rats. Histopathological analysis has shown vascular congestion in heart, thickened alveolar wall and emphysema in lung, and vascular congestion in kidney of rats after sub-acute oral administrations. ConclusionsAs shown in the results, Psammosilene tunicoides has a toxic potential in acute and sub-acute oral administrations. However, there is no direct relationship between toxicity and the cortex. Daily oral administration of three different parts from Psammosilene tunicoides (PR, PRC and PC) may cause damages to heart, lung and kidney in rats. Thus these extracts should be used with caution.

Determination and validation of LJ-2698, a potent human A3 adenosine receptor antagonist, in rat plasma by liquid chromatography-tandem massspectrometry and its application in pharmacokinetic study.

LJ-2698, a highly potent human A3 adenosine receptor antagonist with nucleoside structure, was designed to have a minimal species dependence. For further pre-clinical studies, analytical method for the detection of LJ-2698 in rat plasma was developed by liquid chromatography-tandem mass. Plasma samples were processed by protein precipitation method with acetonitrile, using losartan as the internal standard (IS). Chromatographic separation was carried out using a Kinetex C18 column (100×4.6mm; 100 Å; 2.6 μ) with acetonitrile/water with 0.2% (v/v) formic acid (65:35, v/v) in the isocratic mode at a flow rate of 0.4mL/min. Mass spectrometric detection in multiple reaction monitoring mode was performed with positive electrospray ionization. The mass transitions of LJ-2698 and IS were m/z 412.3→294.1 and m/z 423.1→207.2, respectively. The calibration curves were linear in the range 5.00-5000ng/mL (r 2≥0.998). The lower limit of quantification was established as 5.00ng/mL. Within- and between-run precisions were<7.01%, as relative standard deviation; and accuracies were in the range 3.37-3.64%, as relative error. The validated method was successfully applied to its pharmacokinetic evaluation after intravenous and oral administration in rats, and the dose-dependent pharmacokinetic behavior of LJ-2698 was elucidated for the first time.

Metabolism and disposition of [14C]-methylcyclosiloxanes in rats

Octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) are low molecular weight cyclic volatile methyl siloxanes (cVMSs) primarily used as intermediates or monomers in the production of high molecular weight silicone polymers. The use of D4 as a direct ingredient in personal care products has declined significantly over the past 20 years, although it may be present as a residual impurity in a variety of consumer products. D5 is still used as an intentional ingredient in cosmetics, consumer products and in dry cleaning. Persons who may be exposed include occupational exposure for workers, and potential inhalation or dermal exposure for consumers and the general public. Because of the diverse use, especially of D5, and the potential for human exposure, a comprehensive program was undertaken to understand the kinetics, metabolism, enzyme induction and toxicity of D4 and D5 in rats following relevant routes of exposure. Physiologically based pharmacokinetic (PBPK) models utilizing these studies have been reported for D4 and D5 in the rat and human following dermal and inhalation exposures, with the oral uptake component of the model being limited in its description. Data from high dose oral studies in corn oil and simethicone vehicles and neat were used in the D4/D5 harmonized PBPK model development. It was uncertain if the inability to adequately describe the oral uptake was due to unrealistic high doses or unique aspects of the chemistry of D4/D5. Low dose studies were used to provide data to refine the description of oral uptake in the model by exploring the dose dependency and the impact of a more realistic food-like vehicle. Absorption, distribution, metabolism and elimination (ADME) of D4 and D5 was determined following a single low oral gavage dose of 14C-D4 and 14C-D5 at 30 and 100mg/kg body weight (bw), respectively, in a rodent liquid diet.Comparison of the low vs. high dose oral gavage administration of D4 and D5 demonstrated dose-dependent kinetic behavior. Data and modeling results suggest differences in metabolism between low and high dose administration indicating high dose administration results in or approaches non-linear saturated metabolism. These low dose data sets were used to refine the D4/D5 multi-route harmonized PBPK model to allow for a better description of the disposition and toxicokinetics of D4/D5 following oral exposure. With a refined oral uptake description, the model could be used in risk assessment to better define the internal dose of D4 and D5 following exposure to D4 and D5 via multiple routes.

UV-induced effects on toxicity of model disinfection byproducts

UV (Ultraviolet)-based treatment has been demonstrated to be effective for removal of some disinfection byproducts (DBPs) and to be beneficial for reduction of genotoxicity and cytotoxicity in chlorinated water. However, to a large extent, UV-induced effects on chemistry and toxicology have been treated as a black box, in the sense that little or no UV dose-dependent behavior has been reported. To address this issue, the effects of UV254 irradiation on 1,4-dibenzoquinone (BQ), 2,6-dichloro-1,4-benzoquinone (DCBQ), and chlorocreatinine (Cl-Cre) as model DBPs were examined, both in terms of photodegradation and cytotoxicity. These compounds have been identified as DBPs that are relevant in swimming pool settings; however, these compounds will be relevant in other water treatment settings, including drinking water production and wastewater reuse. UV254 irradiation was shown to promote photodecay of all three compounds. However, for BQ and DCBQ, the corresponding cytotoxicity of the UV-irradiated samples remained essentially unchanged, even when the compound was completely photodegraded. These results indicate that the photodegradation products of BQ and DCBQ carry similar cytotoxicity as their respective parent compounds. On the other hand, UV254-irradiation of Cl-Cre yielded a decrease in cytotoxicity that correlated with photodechlorination of Cl-Cre. These experiments also demonstrated a reduction in cytotoxicity in connection with photodechlorination of an N-chlorinated organic compound. Overall, the results of these experiments indicate the importance of defining products of UV photodecay processes, both in terms of chemistry and toxicity; these attributes are expected to be important in many UV-based applications, including potable water production, water reuse, and recreational water settings.

Novel endodontic sealers induce cell cytotoxicity and apoptosis in a dose-dependent behavior and favorable response in mice subcutaneous tissue.

The objective of the present study is to evaluate the in vitro cytotoxicity and in vivo biocompatibility of two novel endodontic sealers: RealSeal XT1 and Sealapex Xpress on the subcutaneous connective tissue of mice. The cytotoxicity was assessed by cell viability using the MTT assay (one-way ANOVA), trypan blue test (Mann-Whitney) and cell apoptosis by flow cytometer. For the subcutaneous study, polyethylene tubes filled with the sealers were implanted in 70 BALB/c mice: 6 experimental groups (n=10/group) and 2 control groups with empty tubes (n=5/group). At the end of experimental periods (7, 21, and 63days), the tissue was removed and histotechnically processed. Angioblastic proliferation and edema (Fisher's exact test) were evaluated, besides thickness measurement (μm) of the reactionary granulomatous tissue and neutrophil counts (Kruskal-Wallis and Dunn's post test; Mann-Whitney) (α=0.05). MTT assay, trypan blue, and analysis of apoptotic cells showed a dose-dependent direct effect: the more diluted the sealer, the less cytotoxic. Regarding the angioblastic proliferation and edema, difference between the sealers at 7 and 63days occurred (p<0.05). Both endodontic sealers initially promoted perimaterial tissue reaction as a foreign body granuloma and thus stimulated favorable tissue responses. Both sealers showed a dose-dependent effect and promoted satisfactory subcutaneous tissue response; the sealer Sealapex Xpress was less cytotoxic and more biocompatible than RealSeal XT. The step of root canal filling during endodontic treatment is highly important for the preservation of the periapical tissue integrity. Subcutaneous reaction to endodontic sealers enables scientific basis for clinical use.

Pharmacokinetics of Standard- and Reduced-Dose Recombinant Human Soluble Thrombomodulin in Patients with Septic Disseminated Intravascular Coagulation during Continuous Hemodiafiltration.

Recombinant human soluble thrombomodulin (rTM) is reportedly excreted by the kidneys; therefore, the recommended dose for patients with renal impairment is one-third of the standard dose. The aim of this study was to evaluate whether this reduced dose of rTM achieves effective drug concentrations that are comparable to those of the standard dose in treating sepsis-induced disseminated intravascular coagulation (DIC) during continuous hemodiafiltration (CHDF). Eight patients in an intensive care unit were randomized to receive either reduced-dose (0.02 mg/kg, n = 4) or standard-dose (0.06 mg/kg, n = 4) rTM. We evaluated the effect of standard dose in comparison to that of reduced dose on the pharmacokinetics (PKs) of rTM for the sepsis-induced DIC patients receiving CHDF. Patients received rTM during a 30-min infusion for six consecutive days. PK parameters of rTM were analyzed using the one-compartment model. The elimination half-life, clearance (T1/2), and distribution volume of sTM were similar between the reduced and standard doses. The maximum concentration (Cmax) and area under the concentration-time curve (AUC) of sTM were approximately 2.5 times higher with standard-dose daily infusions than that with reduced-dose drip infusions (p = 0.041 and 0.062, respectively). The time when the blood concentration of sTM was >500 ng/mL, i.e., the holding time, was significantly longer with standard-dose infusions than those with reduced dose (p = 0.039). rTM displayed dose-dependent PK behavior at clinically relevant doses. During CHDF, effective blood concentration of rTM was not achieved with the reduced dose, and rTM was found to not bioaccumulate. Therefore, this pilot study suggests that reducing the rTM dose is unnecessary, even in sepsis-induced DIC patients who require CHDF. However, we need to perform a definitive study to determine the dosage of rTM for the case.

The involvement of spinal release of histamine on nociceptive behaviors induced by intrathecally administered spermine

The involvement of spinal release of histamine on nociceptive behaviors induced by spermine was examined in mice. Intrathecal spermine produced dose-dependent nociceptive behaviors, consisting of scratching, biting and licking. The nociceptive behaviors induced by spermine at 0.02 amol and 10 pmol were markedly suppressed by i.t. pretreatment with antiserum against histamine and were abolished in histidine decarboxylase-deficient mice. In histamine H1 receptor-deficient mice, the nociceptive behaviors induced by spermine were completely abolished after treatment with 0.02 amol of spermine and significantly suppressed after treatment with 10 pmol of spermine. The i.t. pretreatment with takykinin NK1 receptor antagonists eliminated the nociceptive behaviors induced by 0.02 amol of spermine, but did not affect the nociceptive behaviors induced by 10 pmol of spermine. On the other hand, the nociceptive behaviors induced by spermine at both 0.02 amol and 10 pmol were suppressed by i.t. pretreatment with antagonists for the NMDA receptor polyamine-binding site. The present results suggest that the nociceptive behaviors induced by i.t. administration of spermine are mediated through the spinal release of histamine and are elicited via activation of NMDA receptors.

Nanoindentation and in situ microcompression in different dose regimes of proton beam irradiated 304 SS

Recent developments in micromechanical testing have allowed for the efficient evaluation of radiation effects in micron-scale volumes of ion-irradiated materials. In this study, both nanoindentation and in situ SEM microcompression testing are carried out on 10 dpa proton beam irradiated 304 stainless steel to assess radiation hardening and radiation-induced deformation mechanisms in the material. Using a focused ion beam (FIB), arrays of 2 μm × 2 μm cross-section microcompression pillars are fabricated in multiple dose regimes within the same grain, providing dose-dependent behavior in a single crystal orientation. Analysis of the microcompression load-displacement data and real-time SEM imaging during testing indicates significant hardening, as well as increased localization of deformation in the irradiated material. Although nanoindentation results suggest that irradiation hardening saturates at low doses, microcompression results indicate that the pillar yield stress continues to rise with dose above 10 dpa in the tested orientation.

Incorporation of chloramphenicol and captopril into poly(GL)‐b‐poly(GL‐co‐TMC‐co‐CL)‐b‐poly(GL) monofilar surgical sutures

ABSTRACTIncorporation of chloramphenicol and captopril into coated and uncoated monofilament sutures was evaluated, as well as the derived bactericide and wound healing effects. To this end, a commercially available suture and an amorphous random copolymer constituted by trimethylene carbonate and lactide units were considered. The suture had a segmented architecture based on polyglycolide hard blocks and a soft block constituted by glycolide, trimethylene carbonate and ε‐caprolactone units. Chloramphenicol was better loaded when the coating copolymer was employed due to its protective effect whereas captopril showed an opposite behavior due to partial solubilization during immersion in the coating bath. Interestingly, the release behavior was very different for the two studied drugs since a significant retention of chloramphenicol was always detected, suggesting the establishment of interactions between drug and copolymers. On the other hand, delivery of captopril showed a typical dose dependent behavior. A low in vitro toxicity of the two drugs was determined considering both epithelial‐like and fibroblast‐like cells. Bactericide effect of chloramphenicol against Gram‐negative and Gram‐positive bacteria was demonstrated at a dose that was non‐toxic for all assayed cells. An accelerating wound healing effect of captopril was also demonstrated for early events. In this case, the use of a coating copolymer was fundamental to avoid cytotoxic effects on highly loaded sutures. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44762.