Microglia depletion exacerbates demyelination and impairs remyelination in a neurotropic coronavirus infection.

Microglia are considered both pathogenic and protective during recovery from demyelination, but their precise role remains ill defined. Here, using an inhibitor of colony stimulating factor 1 receptor (CSF1R), PLX5622, and mice infected with a neurotropic coronavirus (mouse hepatitis virus [MHV], strain JHMV), we show that depletion of microglia during the time of JHMV clearance resulted in impaired myelin repair and prolonged clinical disease without affecting the kinetics of virus clearance. Microglia were required only during the early stages of remyelination. Notably, large deposits of extracellular vesiculated myelin and cellular debris were detected in the spinal cords of PLX5622-treated and not control mice, which correlated with decreased numbers of oligodendrocytes in demyelinating lesions in drug-treated mice. Furthermore, gene expression analyses demonstrated differential expression of genes involved in myelin debris clearance, lipid and cholesterol recycling, and promotion of oligodendrocyte function. The results also demonstrate that microglial functions affected by depletion could not be compensated by infiltrating macrophages. Together, these results demonstrate that microglia play key roles in debris clearance and in the initiation of remyelination following infection with a neurotropic coronavirus but are not necessary during later stages of remyelination.

A Call for Increased Focus on Reproductive Health within Lab Safety Culture.

The approach to reproductive health and safety in academic laboratories requires increased focus and a shift in paradigm. Our analysis of the current guidance from more than 100 academic institutions' Chemical Hygiene Plans (CHPs) indicates that the burden to implement laboratory reproductive health and safety practices is often placed on those already pregnant or planning conception. We also found inconsistencies in the classification of potential reproductive toxins by resources generally considered to be authoritative, adding further confusion. In the interest of human health and safe laboratory practice, we suggest straightforward changes that institutions and individual laboratories can make to address these present deficiencies: Provide consistent and clear information to laboratory researchers about reproductive health and normalize the discussion of reproductive health among all researchers. Doing so will promote safer and more inclusive laboratory environments.

JNJ-56136379, an HBV Capsid Assembly Modulator, Is Well-Tolerated and Has Antiviral Activity in a Phase 1 Study of Patients With Chronic Infection.

BACKGROUND & AIMS: JNJ-56136379 (JNJ-6379), a capsid assembly modulator that blocks hepatitis B virus (HBV) replication, was well tolerated and demonstrated dose-proportional pharmacokinetics in healthy participants in part 1 of its first clinical trial. In part 2, we have evaluated the safety, pharmacokinetics, and antiviral activity of multiple doses of JNJ-6379 in patients with chronic HBV infection. METHODS: We performed a double-blind study of 57 treatment-naïve patients with HB e antigen-positive or -negative (74%) chronic HBV infection without cirrhosis. Patients were randomly assigned to groups given JNJ-6379 at 25 mg (100 mg loading dose), 75 mg, 150 mg, or 250 mg or placebo daily for 4 weeks with an 8-week follow-up period. RESULTS: Twenty-three (56%) of 41 patients given JNJ-6379 had at least 1 adverse event (AE) during treatment, compared with 10 (63%) of 16 patients given placebo. No serious AEs were reported during the treatment period. Three patients (7%) given JNJ-6379 vs none given placebo had grade 3 AEs; of these, 1 patient (150 mg) also had an isolated grade 4 increase in the level of alanine aminotransferase that led to treatment discontinuation. JNJ-6379 exposure increased with dose, with time-linear pharmacokinetics. HBV-DNA and HBV-RNA decreased from baseline in patients receiving all doses of JNJ-6379, independently of viral genotype and HB e antigen status. On day 29, 13 (32%) of 41 patients had levels of HBV DNA below the lower limit of quantification. No clinically significant changes in levels of HB surface antigen were observed. CONCLUSIONS: In a phase 1 study of treatment-naïve patients with chronic HBV infection, all doses tested of JNJ-6379 were well tolerated, showed dose-dependent pharmacokinetics, and had potent antiviral activity in patients with CHB. The findings support a phase 2a study to evaluate JNJ-6379 ± nucleos(t)ide analogs in patients with chronic HBV infection, which is under way. ClinicalTrials.gov identifier: NCT02662712.

In Silico Assessment of Acute Oral Toxicity for Mixtures.

While exposure of humans to environmental hazards often occurs with complex chemical mixtures, the majority of existing toxicity data are for single compounds. The Globally Harmonized System of chemical classification (GHS) developed by the Organization for Economic Cooperation and Development uses the additivity formula for acute oral toxicity classification of mixtures, which is based on the acute toxicity estimate of individual ingredients. We evaluated the prediction of GHS category classifications for mixtures using toxicological data collected in the Integrated Chemical Environment (ICE) developed by the National Toxicology Program (United States Department of Health and Human Services). The ICE database contains in vivo acute oral toxicity data for ∼10,000 chemicals and for 582 mixtures with one or multiple active ingredients. By using the available experimental data for individual ingredients, we were able to calculate a GHS category for only half of the mixtures. To expand a set of components with acute oral toxicity data, we used the Collaborative Acute Toxicity Modeling Suite (CATMoS) implemented in the Open Structure-Activity/Property Relationship App to make predictions for active ingredients without available experimental data. As a result, we were able to make predictions for 503 mixtures/formulations with 72% accuracy for the GHS classification. For 186 mixtures with two or more active ingredients, the accuracy rate was 76%. The structure-based analysis of the misclassified mixtures did not reveal any specific structural features associated with the mispredictions. Our results demonstrate that CATMoS together with an additivity formula can be used to predict the GHS category for chemical mixtures.

Integrated In Silico Models for the Prediction of No-Observed-(Adverse)-Effect Levels and Lowest-Observed-(Adverse)-Effect Levels in Rats for Sub-chronic Repeated-Dose Toxicity.

Repeated-dose toxicity (RDT) is a critical endpoint for hazard characterization of chemicals and is assessed to derive safe levels of exposure for human health. Here we present the first attempt to model simultaneously no-observed-(adverse)-effect level (NO(A)EL) and lowest-observed-(adverse)-effect level (LO(A)EL). Classification and regression models were derived based on rat sub-chronic repeated dose toxicity data for 327 compounds from the Fraunhofer RepDose database. Multi-category classification models were built for both NO(A)EL and LO(A)EL though a consensus of statistics- and fragment-based algorithms, while regression models were based on quantitative relationships between the endpoints and SMILES-based attributes. NO(A)EL and LO(A)EL models were integrated, and predictions were compared to exclude inconsistent values. This strategy improved the performance of single models, leading to R2 greater than 0.70, root-mean-square error (RMSE) lower than 0.60 (for regression models), and accuracy of 0.61-0.73 (for classification models) on the validation set, based on the endpoint and the threshold applied for selecting predictions. This study confirms the effectiveness of the modeling strategy presented here for assessing RDT of chemicals using in silico models.

Mice derived from in vitro αMEM-cultured preimplantation embryos exhibit postprandial hyperglycemia and higher inflammatory gene expression in peripheral leukocytes.

We examined whether peripheral leukocytes of mice derived from in vitro αMEM-cultured embryos and exhibiting type 2 diabetes had higher expression of inflammatory-related genes associated with the development of atherosclerosis. Also, we examined the impact of a barley diet on inflammatory gene expression. Adult mice were produced by embryo transfer, after culturing two-cell embryos for 48 h in either α minimal essential media (α-MEM) or potassium simplex optimized medium control media. Mice were fed either a barley or rice diet for 10 weeks. Postprandial blood glucose and mRNA levels of several inflammatory genes, including Tnfa and Nox2, in blood leukocytes were significantly higher in MEM mice fed a rice diet compared with control mice. Barley intake reduced expression of S100a8 and Nox2. In summary, MEM mice exhibited postprandial hyperglycemia and peripheral leukocytes with higher expression of genes related to the development of atherosclerosis, and barley intake reduced some gene expression.

A phase I, randomized, double-blind study to assess the safety, tolerability and efficacy of the topical RORC2 inverse agonist PF-06763809 in participants with mild-to-moderate plaque psoriasis.

BACKGROUND: Transcription factor retinoic acid-related orphan receptor 2 (RORC2/RORγT) mediates interleukin (IL)-17A and IL-17F expression. IL-17A plays a central role in the pathogenesis of several inflammatory disorders, including psoriasis. The RORC2 inhibitor PF-06763809 has been hypothesized to inhibit IL-17A production in T-helper 17 (Th17) cells, thereby reducing psoriasis symptoms. AIM: To assess the safety, tolerability and effect on skin infiltrate thickness of PF-06763809 in participants with mild/moderate chronic plaque psoriasis. METHODS: This was a randomized, double-blind, first-in-human study (trial registration: ClinicalTrials.gov NCT03469336). Participants received each of the following six treatments once daily for 18 days: three topical doses (2.3%, 0.8%, 0.23%) of PF-06763809, a vehicle and two active comparators (betamethasone and calcipotriol). Primary endpoints included change from baseline in psoriatic skin infiltrate thickness [echo-poor band (EPB) on ultrasonography] at Day 19, and safety. Change in psoriasis-associated gene expression (Day 19), evaluated by real-time reverse transcription PCR of skin biopsies, was an exploratory endpoint. RESULTS: In total, 17 participants completed the study. Change from baseline in the EPB on Day 19 for all three doses of PF-06763809 was not significantly different from that of vehicle (P > 0.05). A significant reduction in EPB from baseline was observed with betamethasone on Day 19 relative to all other treatments (P < 0.0001). Treatment-related adverse events were mild/moderate. There were no significant differences in gene expression on Day 19 between vehicle and PF-06763809-treated skin lesions. CONCLUSION: Using a psoriasis plaque test design, PF-06763809 was found to be well tolerated with an acceptable safety profile in participants with psoriasis, but without reduction in skin infiltrate thickness or disease biomarkers.

A first-in-human study to evaluate the safety, tolerability and pharmacokinetics of RP3128, an oral calcium release-activated calcium (CRAC) channel modulator in healthy volunteers.

WHAT IS KNOWN AND OBJECTIVE: RP3128, a novel, orally available modulator of calcium released activated calcium (CRAC) channel, is being developed for the potential treatment of autoimmune and inflammatory diseases. RP3128 showed nano-molar potency and activity in a range of in vitro and in vivo models of inflammation. We report a first-in-human study investigating the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of RP3128 in healthy subjects. METHODS: A randomized, double-blind, placebo-controlled trial of single (25, 50, 100, 200 and 400 mg) and multiple (7 days: 25, 100 and 400 mg once daily) doses of RP3128 were performed. Thirty-two and 24 subjects were randomized in the single ascending dose (SAD) and multiple ascending dose (MAD) parts, respectively. RESULTS AND DISCUSSION: RP3128 was well tolerated, with no dose-limiting toxicity at single and multiple doses. Incidence of treatment emergent adverse events (TEAEs) did not increase with ascending RP3128 doses. No changes were seen in cognitive function and ECG parameters. RP3128 was rapidly absorbed. Elimination was slow with a half-life of more than 80 h. Exposures increased with increasing doses. Accumulation was seen on repeated dosing. PD response, as evidenced by lower plasma levels of tumour necrosis factor-alfa (TNFα) and interleukin-4 (IL-4), was seen when compared to pre-dose values or placebo. WHAT IS NEW AND CONCLUSION: The safety, tolerability and PK/PD profile of RP3128 demonstrates its potential to be developed in inflammatory disorders and support further clinical development (ClinicalTrials.gov number: NCT02958982).

Metal Oxide Nanoparticles: Evidence of Adverse Effects on the Male Reproductive System.

Metal oxide nanoparticles (MONPs) are inorganic materials that have become a valuable tool for many industrial sectors, especially in healthcare, due to their versatility, unique intrinsic properties, and relatively inexpensive production cost. As a consequence of their wide applications, human exposure to MONPs has increased dramatically. More recently, their use has become somehow controversial. On one hand, MONPs can interact with cellular macromolecules, which makes them useful platforms for diagnostic and therapeutic interventions. On the other hand, research suggests that these MONPs can cross the blood-testis barrier and accumulate in the testis. Although it has been demonstrated that some MONPs have protective effects on male germ cells, contradictory reports suggest that these nanoparticles compromise male fertility by interfering with spermatogenesis. In fact, in vitro and in vivo studies indicate that exposure to MONPs could induce the overproduction of reactive oxygen species, resulting in oxidative stress, which is the main suggested molecular mechanism that leads to germ cells' toxicity. The latter results in subsequent damage to proteins, cell membranes, and DNA, which ultimately may lead to the impairment of the male reproductive system. The present manuscript overviews the therapeutic potential of MONPs and their biomedical applications, followed by a critical view of their potential risks in mammalian male fertility, as suggested by recent scientific literature.

Supporting Fundamental Chemical Toxicology Research To Inform Medical Countermeasure Developments: The National Institutes of Health Chemical Countermeasures Research Program.

A high-consequence chemical emergency is a major public health concern. In the United States, the National Institute of Allergy and Infectious Diseases within the National Institutes of Health pioneers discovery and early development of critical medical countermeasures against chemical threats.

Case-control study of brain and other central nervous system cancer among workers at semiconductor and storage device manufacturing facilities.

OBJECTIVE: This study evaluated the relationship between brain and other central nervous system cancer ('CNS cancer') and exposures at two semiconductor and electronic module manufacturing facilities and at a storage device manufacturing facility. METHODS: The case-control study, nested in a cohort of 126 836 employees, compared 120 CNS cancer cases and 1028 matched controls with respect to employment in 10 process groups and estimated cumulative exposure to 31 known or possible carcinogens. RESULTS: CNS cancer was associated with module manufacturing operations at two facilities. Module manufacturing is a process that begins with production of ceramic substrates followed by attachment of completed semiconductor chips and metal-containing circuitry resulting in a high performing electronic device. Positive associations with the highest tertile of estimated cumulative exposure were found for several chemicals, including 2-butoxyethanol, cyclohexanone, ortho-dichlorobenzene, cadmium, molybdenum, trichloroethylene and vinyl chloride. CONCLUSIONS: Results suggested positive associations between CNS cancer and specific operations and chemicals experienced in the semiconductor and electronic module manufacturing industry. However, lack of external support for these findings precludes a causal interpretation, and the observed associations may have been due to chance.

Effect of fatty fish or nut consumption on concentrations of persistent organic pollutants in overweight or obese men and women: A randomized controlled clinical trial.

BACKGROUND AND AIMS: While excess energy intake and physical inactivity constitute the obvious causes of body fat accumulation, persistent organic pollutants (POPs) are novel factors that have been linked to cardiometabolic disorders. Major sources of POPs are animal fats including fatty fish. Given the putative protective effects of fish on cardiovascular disease, we explored whether high consumption of fatty fish increased serum concentrations of POPs. METHODS AND RESULTS: Men and women aged 35-70 years with body mass index between 25 and 38 kg/m2 and at least 1 cardiometabolic component were randomized to high intakes of fatty fish (mostly farmed salmon, ∼630 g/week; n = 45), high intakes of nuts (∼200 g/week; n = 42) or a control group following their usual diet but restricting fatty fish and nuts for 6 months (n = 44). Concentrations of 15 POPs (5 organochlorinated compounds, 2 dioxin-like polychlorinated biphenyls and 8 non-dioxin-like polychlorinated biphenyls) and cardiometabolic risk factors were measured at baseline and end of the study. Results showed that changes in concentrations of individual and classes of POPs did not differ between the dietary groups and controls (p > 0.05). Among cardiometabolic risk factors HDL-cholesterol increased in the fatty fish group compared to controls (+0.10 mmol/L, CI (0.05-0.20); p = 0.005) while no changes were observed in the group consuming nuts. CONCLUSION: Fatty fish consumption for 6 months did not increase the serum concentrations of POPs in individuals with overweight or obesity and metabolic risk. While this finding appears reassuring regarding short-term intakes of farmed salmon, long term variations in POPs in adipose stores require further study.

Time extrapolation in regulatory risk assessment: The impact of study differences on the extrapolation factors.

In human risk assessment, time extrapolation factors (EFs) account for differences in exposure duration of experimental studies. We calculated EFs based on N(L)OEL (no (lowest) observed effect level) ratios, dividing shorter-term by longer-term values. The 'oral' datasets comprised 302 EFs (subacute-subchronic) and 1059 EFs (subchronic-chronic). The 'inhalation' datasets contained 67 EFs (subacute-subchronic) and 226 EFs (subchronic-chronic). The experimental EF distribution oral:subchronic-chronic showed that study parameters like deviation in dose selection and spacing influence mainly the data variance. Exclusion of these influences led to a dataset representing more realistically the difference of N(L)OELs with prolonged treatment. This dataset showed a GM of 1.5, indicating that the impact of a longer treatment period on the study N(L)OEL is on average not high. A factor of 1.5 seemed to be also sufficiently conservative for subacute-subchronic and subchronic-chronic extrapolation (inhalation or oral exposure). EFs for groups of similar compounds did not differ, but for compounds with low and high NOEL values. Relatively toxic compounds (GM 1) might thus not require time extrapolation. Within and between chemical variance was analysed in the dataset oral:subchronic-chronic (GSD 4.8). The variance between chemicals should be considered within extrapolation by selecting an appropriate percentile for which a chemical variance factor is suggested. In risk assessment, often a combination of EFs is required. Our analysis indicates that such a combination will result in an accumulation of non-toxicological variance and therefore unrealistically high EFs. Further evaluations are needed to identify appropriate chemical variance factors for these situations.

[Evaluation of drug-drug interactions between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets].

Objective: To evaluate the drug-drug interactions and the tolerability of combined medication between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets in healthy volunteers. Methods: A randomized, open, and continuous administration design was used in trial 1 (yimitasvir phosphate capsules with sofosbuvir tablets). 28 subjects were randomly divided into two groups. A non-randomized, open design was used in trial 2 (yimitasvir phosphate capsules with omeprazole magnesium enteric-coated tablets), and included 42 subjects divided into three groups. The open design method was used in trial 3 (yimitasvir phosphate capsules with rosuvastatin calcium tablets), and included 14 subjects. The plasma concentrations of yimitasvir phosphate, sofosbuvir and their main metabolites GS-331007, omeprazole and rosuvastatin were validated by a liquid chromatography/tandem mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated by Phoenix winNonlin software. Results: (1) in trial 1, after single and co-administration, the 90% CI of sofosbuvir C(max) and AUC(0-tau) geometric mean ratio (GMR) were 152.0% (118.0% ~ 197.0%) and 230.0% (184.0% ~ 287.0%), with an increase of 52.0% and 130.0% compared to single dose of sofosbuvir, respectively. The 90% CI of GS-331007 C(max) GMR was 74.0% (67.5% ~ 81.2%) and reduced by 26% compared to single dose of sofosbuvir. (2) in trial 2, the 90% CI of C(max) GMR after yimitasvir single or co-administration at the same time, with a 4-hours interval, or with a 12- hours interval were 68.9% (44.5% ~ 106.7%) , 64.0% (43.8% ~ 93.6%) and 56.4%(38.9% ~ 81.9%), and the 90% CI of AUC(0-t) GMR were 68.6% (46.5% ~ 101.2%), 68.3% (47.6% ~ 98.0%) and 60.5% (41.8% ~ 87.5%), respectively. Compared with single dose of yimitasvir, the C(max) and AUC(0-t) were decreased by 31.1% and 31.4%, 36.0% and 31.7%, 43.6% and 39.5%, respectively. (3) In trial 3, after single and co-administration, the 90% CI of rosuvastatin C(max) and AUC(0-72) GMR were 172.4% (153.6% ~ 193.5%) and 158.0% (144.3% ~ 172.9%), respectively, with an increase of 74.9% and 60.5% compared to single dose of rosuvastatin. There were no serious adverse events and adverse events leading to withdrawal from the trial. Conclusion: Yimitasvir phosphate capsules have drug-drug interactions with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets.

Microglia Are Critical in Host Defense against Prion Disease.

Microglial cells in the central nervous system play important roles in neurodevelopment and resistance to infection, yet microglia can become neurotoxic under some conditions. An early event during prion infection is the activation of microglia and astrocytes in the brain prior to damage or death of neurons. Previous prion disease studies using two different strategies to manipulate signaling through the microglial receptor CSF-1R reported contrary effects on survival from prion disease. However, in these studies, reductions of microglial numbers and function were variable, thus confounding interpretation of the results. In the present work, we used oral treatment with a potent inhibitor of CSF-1R, PLX5622, to eliminate 78 to 90% of microglia from cortex early during the course of prion infection. Oral drug treatment early after infection with the RML scrapie strain significantly accelerated vacuolation, astrogliosis, and deposition of disease-associated prion protein. Furthermore, drug-treated mice had advanced clinical disease requiring euthanasia 31 days earlier than untreated control mice. Similarly, PLX5622 treatment during the preclinical phase at 80 days postinfection with RML scrapie also accelerated disease and resulted in euthanasia of mice 33 days earlier than infected controls. PLX5622 also accelerated clinical disease after infection with scrapie strains ME7 and 22L. Thus, microglia are critical in host defense during prion disease. The early accumulation of PrPSc in the absence of microglia suggested that microglia may function by clearing PrPSc, resulting in longer survival.IMPORTANCE Microglia contribute to many aspects of health and disease. When activated, microglia can be beneficial by repairing damage in the central nervous system (CNS) or they can turn harmful by becoming neurotoxic. In prion and prionlike diseases, the involvement of microglia in disease is unclear. Previous studies suggest that microglia can either speed up or slow down disease. In this study, we infected mice with prions and depleted microglia from the brains of mice using PLX5622, an effective CSF-1R tyrosine kinase inhibitor. Microglia were markedly reduced in brains, and prion disease was accelerated, so that mice needed to be euthanized 20 to 33 days earlier than infected control mice due to advanced clinical disease. Similar results occurred when mice were treated with PLX5622 at 80 days after infection, which was just prior to the start of clinical signs. Thus, microglia are important for removing prions, and the disease is faster when microglia are depleted.

Industrial, Biocide, and Cosmetic Chemical Inducers of Cholestasis.

A frequent side effect of many drugs includes the occurrence of cholestatic liver toxicity. Over the past couple of decades, drug-induced cholestasis has gained considerable attention, resulting in a plethora of data regarding its prevalence and mechanistic basis. Likewise, several food additives and dietary supplements have been reported to cause cholestatic liver insults in the past few years. The induction of cholestatic hepatotoxicity by other types of chemicals, in particular synthetic compounds, such as industrial chemicals, biocides, and cosmetic ingredients, has been much less documented. Such information can be found in occasional clinical case reports of accidental intake or suicide attempts as well as in basic and translational study reports on mechanisms or testing of new therapeutics in cholestatic animal models. This paper focuses on such nonpharmaceutical and nondietary synthetic chemical inducers of cholestatic liver injury, in particular alpha-naphthylisocyanate, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, methylenedianiline, paraquat, tartrazine, triclosan, 2-octynoic acid, and 2-nonynoic acid. Most of these cholestatic compounds act by similar mechanisms. This could open perspectives for the prediction of cholestatic potential of chemicals.

Baseline Toxicity and Volatility Cutoff in Reporter Gene Assays Used for High-Throughput Screening.

Most studies using high-throughput in vitro cell-based bioassays tested chemicals up to a certain fixed concentration. It would be more appropriate to test up to concentrations predicted to elicit baseline toxicity because this is the minimal toxicity of every chemical. Baseline toxicity is also called narcosis and refers to nonspecific intercalation of chemicals in biological membranes, leading to loss of membrane structure and impaired functioning of membrane-related processes such as mitochondrial respiration. In cells, baseline toxicity manifests as cytotoxicity, which was quantified by a robust live-cell imaging method. Inhibitory concentrations for baseline toxicity varied by orders of magnitude between chemicals and were described by a simple quantitative structure activity relationship (QSAR) with the liposome-water partition constant as a sole descriptor. The QSAR equations were remarkably similar for eight reporter gene cell lines of different cellular origin, six of which were used in Tox21. Mass-balance models indicated constant critical membrane concentrations for all cells and all chemicals with a mean of 69 mmol·kglip-1(95% CI: 49-89), which is in the same range as for bacteria and aquatic organisms and consistent with the theory of critical membrane burden of narcosis. The challenge of developing baseline QSARs for cell lines is that many confirmed baseline toxicants are rather volatile. We deduced from cytotoxicity experiments with semi-volatile chemicals that only chemicals with medium-air partition constants >10,000 L/L can be tested in standard robotic setups without appreciable loss of effect. Chemicals just below that cutoff showed crossover effects in neighboring wells, whereas the effects of chemicals with lower medium-air partition constants were plainly lost. Applying the "volatility cut-off" to >8000 chemicals tested in Tox21 indicated that approximately 20% of Tox21 chemicals could have partially been lost during the experiments. We recommend applying the baseline QSARs together with volatility cut-offs for experimental planning of reporter gene assays, that is, to dose only chemicals with medium-air partition constants >10,000 at concentrations up to the baseline toxicity level.

A review of substances found positive in 1 of 3 in vitro tests for skin sensitization.

There has been significant progress in recent years in the development and application of alternative methods for assessing the skin sensitization potential of chemicals. The pathways involved in skin sensitization have been described in an OECD adverse outcome pathway (AOP). To date, a single non-animal test method is not sufficient to address this AOP so numerous approaches involving the use of 2 or more assays are being evaluated for their performance. The 2 out of 3 approach is a simple approach that has demonstrated very good sensitivity, specificity and overall accuracy numbers for predicting the skin sensitization potential of chemicals. Chemicals with at least two positive results in tests addressing Key events 1-3 are predicted sensitizers, while chemicals with none or only one positive outcome are predicted non-sensitizers. In this report we have thoroughly reviewed the discordant results of 29 chemicals with 1 out of 3 positive results to understand better what led to the results observed and how this information might impact our hazard assessments of these chemicals. We initially categorized each chemical using a weight of evidence approach as positive, negative or indeterminate based on review of available human and animal data as well as what skin sensitization alerts were triggered using two versions of OECD Toolbox and DEREK Nexus. We determined that 4 of the 29 chemicals should be classified as indeterminate and not included in analysis of method performance based on insufficient, borderline and/or conflicting data to confidently categorized the chemicals as allergens or non-allergens. Of the 29 chemicals included in this analysis, 17 were classified as negative and would be correctly identified using a 2 out of 3 approach while 8 chemicals were classified as positive in vivo and would be false-negative with this approach. For some of these chemicals, the outcomes observed can be explained by in vitro borderline results (13 chemicals) or in some instances there is mechanistic understanding of why a chemical is positive or negative in a particular assay (9 chemicals). Thus, when comparing the performance of different defined approaches, one should attempt to only include chemicals which demonstrate clear evidence to be categorize as allergens or non-allergens. Finally, when interpreting the results obtained for an individual unknown chemical it is critical that the in vitro skin sensitization data is reviewed critically and there is a good understanding of the variance and applicability domain limitations for each assay being used.

The impact on classifications for carcinogenicity, mutagenicity, reproductive and specific target organ toxicity after repeated exposure in the first ten years of the REACH regulation.

The present study primarily aims at informing regulators and policy makers in Europe and examines the evolution of self-classifications and study availability for the endpoints of carcinogenicity, mutagenicity, reproductive toxicity (CMR) and specific target organ toxicity after repeated exposure (STOT RE) for the first ten years of the REACH legislation. Our knowledge on chemical safety keeps increasing due to the registration obligations under REACH, in combination with proactive actions by registrants and regulatory actions by Authorities, which jointly lead to new testing and critical reassessment of existing studies. The improvements become evident by the constant increase in the number of substances that are self-classified by the registrants for human health endpoints. Moreover, there is a slow but steady increase in the number of substances for which there is at least one experimental study available for the human health endpoints in scope of this analysis. However, the increase is slow given the generally limited data availability at the beginning of REACH. Manual examination of about 350 classified substances reveals that the impact of newly generated data and regulatory action by Authorities is greater for reproductive toxicity than for carcinogenicity or mutagenicity, reflecting the strengthening of the information requirements for reproductive toxicity with the introduction of REACH. The results of the study should inform regulators and policy makers at EU and national level in the discussion on potential changes to information requirements or testing strategies under REACH.

[Characteristic analysis of organic fluorosis caused by appliying of touch screen anti-fingerprint nanocoating material].

Objective: To analysis pathogenic conditions and pathogenic characteristics of organic fluorosis caused by applying of anti-fingerprint coating material on touch screen glass of the mobile phone. Methods: To collect clinical data and analyze the causes and pathogenic characteristics of poisoning through surveying occupational health, detecting occupational hazards in the workplace, collecting clinical data and diagnosing of occupational diseases. 6 employees in workshop 1 of packaging were as the organic fluorine exdposed group, and 16 employees in other workshops were as the non-exposed group. Results: Organic fluorine chemicals (perfluoro-1, 3-dimethylcyclohexane, hexadecafluoroheptane, perfluoro-hexane, perfluoromethy lopentane, perfluoro-2-methyl-2-pentene, etc.) can be volatilized by spraying and baking of anti-fingerprint nano-coating material on touch screen. The relative percentage of volatile components in air is 85.65%. Four cases of acute poisoning were caused by organic fluorosis deposited in a dustless air conditioning workshop with poor ventilation.The clinical manifestations of the patients were acute bronchitis, pulmonary edema and/or myocarditis. The average concentration of urine fluorine in the organic fluorine exposed group was 13.7± 4.4 mmol/mol creatinine, which was 4-5 times higher than that of other non-organic fluorine exposed groups. The difference of urine fluorine level between the organic fluorine exposed group and non exposed group was statistically significant (P<0.01) . The main indicators were abnormal for the blood oxygen saturation of finger pulse under suction air, leukocytes, neutrophils, monocytes, hypersensitivec-reactive protein, procalcitonin, l-lactate dehydrogenase, forebrain diuretic natriuretic peptide, hypersensitive troponin T in the four cases. One case was myocardial ischemia, four cases had bilateral lung symmetrically exudative lesions, one case was accompanied by a small amount of pleural pericardial effusion. Conclusion: Acute organofluorine poisoning can caused by the applying of the fingerprint nano-coating material on touch screen of the mobile phone. Attention should be paid to occupational poisoning caused by the applying of the small molecular perfluoroalkanes (olefins) in new industries, new processes and new materials.