No-observed-adverse-effect Level Research Articles

Juvenile toxicity of atropine sulfate eye drops in young rats

Objectives This study was to investigate the effects of atropine sulphate eye drops (ASED)on the development of partial systems in young rats and their toxic reactions following repeated eye-drop administration over a period of 40 days. Methods SD rats of 20 days old were randomly assigned to control group, 0.01, 0.02, and 0.04% ASED groups, with 60 females and 25 males per group. ASED was given by eye drops from PND21 onwards and normal saline was given in the control group at 10 μL/eye once a day for 40 days, in both right and left eyes. Rats of ASED groups were instilled with eye drops at the 10 μL/day per eye, from postnatal day 21 (PND21) to PND60 for 40 consecutive days. The clinical observation, body weight, food intake, physical development, physiological development, reproductive development, ophthalmic examination, intraocular pressure, and axial length of the rats were examined during the study period. Results ASED at concentrations of 0.01, 0.02, 0.04%, dose levels of 0.002, 0.004, 0.008 mg/day per rat, had no toxicological effects on the clinical observation, body weight, food intake, physical development, physiological development, reproductive development, ophthalmic examination, intraocular pressure, and axial length in rats. Conclusion The no-observed-adverse-effect-level (NOAEL) of ASED in young SD rats equivalent to human over 2 years old was 0.008 mg/day at a concentration of 0.4 mg/mL.

Effects of the insecticide chlorpyrifos on Amazonian freshwater invertebrates: A mesocosm experiment

Chlorpyrifos is one of the most widely used insecticides globally, yet its toxicity for tropical aquatic ecosystems in Latin America has not been thoroughly evaluated. In this study, we conducted a 70-day mesocosm experiment to assess the effects of chlorpyrifos on zooplankton and macroinvertebrate communities representative of the Ecuadorian Amazon. Mesocosms were exposed to a single application of chlorpyrifos at four nominal concentrations (0.01, 0.1, 1, and 10 μg/L). Results showed rapid chlorpyrifos dissipation, with a half-life of 1.2 days. For some Rotifera species, including Polyarthra luminosa and Anuraeopsis sp., a consistent No Observable Effect Concentration (NOEC) of 0.01 μg/L was identified. Cyclopoida (e.g., Macrocyclops sp.) also displayed treatment-related declines, with a NOEC of 0.1 μg/L. Among macroinvertebrates, the most sensitive taxon was the Ephemeropteran Caenis sp. (NOEC: 0.1 μg/L), while other insect taxa (Odonata, Diptera) also showed significant treatment-related declines. Based on the response of some Rotifera species and the zooplankton community, we determined a mesocosm NOEC of 0.01 μg/L. The response of Rotifera taxa was explained by indirect effects resulting from a decline in copepod populations within the experimental systems, which led to an increase in Cladocera (e.g., Moina sp.), effective grazers on small rotifers. Our findings suggest a mesocosm NOEC slightly lower than those reported in other tropical and temperate studies (0.1 μg/L), potentially due to differences in species composition and interactions. Finally, our study highlights that measured chlorpyrifos concentrations in Latin American surface waters exceed levels at which both direct and indirect effects have been observed. Additional monitoring and regulatory measures are needed to control chlorpyrifos use and environmental release in tropical regions with intensive agriculture and high rainfall.

Bacillus subtilis ZB423: 90-Day repeat dose oral (gavage) toxicity study in Wistar rats.

The novel genetically modified probiotic Bacillus subtilis ZB423 was assessed in a 90-day repeated-dose oral toxicity study adhering to Good Laboratory Practice (GLP) and Organization for Economic Cooperation and Development (OECD) guidelines. Spray-dried spores at a concentration of 1.1E12 CFU/g were administered at doses of 130, 260, and 519 mg/kg body weight/day correlating to 1.43 × 1011, 2.86 × 1011, and 5.71 × 1011 CFU/kg/day, respectively, by oral gavage to Wistar rats for a period of 90 consecutive days. Results showed no toxicologically relevant findings for B. subtilis ZB423 from measured parameters. The no observed adverse effect level (NOAEL) of B. subtilis ZB423 is 519 mg/kg body weight/day corresponding to 5.71 × 1011 CFU/kg/day for lyophilized B. subtilis ZB423 spores under the test conditions employed.

Female rat liver after sub-acute dibutyl phthalate treatment: Histological, stereological, biochemical, and global gene expression study

Although it has been recognized that females are more susceptible to chemical-induced liver injury, the effects of dibutyl phthalate (DBP), a widely used synthetic chemical, on female liver structure and function are under-researched. Here, we sought to investigate the effects of DBP on histological, stereological, and biochemical parameters, as well as global gene expression in female rat liver. Female Wistar rats were exposed to 100, 500, and 5000 mg DBP/kg diet for 28 days, corresponding to 8.6, 41.43, and 447.33 mg DBP/kg body weight (B.W.)/day, respectively. The highest dose (447.33 mg DBP/kg B.W./day) was between the no-observed-adverse-effect level (NOAEL) and the lowest-observed-adverse-effect level for liver toxicity, whereas two lower doses (8.6 and 41.43 mg DBP/kg B.W./day) were below the NOAEL. Analysis of hematoxylin and eosin-stained sections revealed an increased volume of hepatocytes, their nuclei and cytoplasm, while the volume of sinusoids decreased in DBP-exposed groups compared to the control. Examination of Periodic acid-Schiff-stained sections showed reduced glycogen content, which was the most prominent in the highest dose group. Increased glutathione S-transferase and catalase activities, and decreased GSH content and superoxide dismutase activity were observed in DBP-exposed groups. The mRNA sequencing revealed DBP-induced dose-specific changes in various genes and biological functions in female rat liver. The highest number of deregulated genes was observed in the 500 mg DBP/kg diet group. In summary, exposure to DBP caused significant liver microstructural changes, decreased glycogen content, disturbed the redox status, and affected global gene expression in female rat liver.

Uncertainty Analysis in Ecological Risk Assessment: Sensitivity Analysis of Different Exposure Models

Ecological risk assessments are used for decision making regarding releasing new products to market as well as remedial action required to address contamination at legacy sites. Uncertainty analysis is considered a key part of the process (USEPA 1997) but assessments seldom address uncertainty quantitatively. Key sources of uncertainty include: Sampling and analytical variability (soil/ sediment matrix, lab error), Choice of “Indicator” Species as Target Receptors for Different Exposure Pathways, Sample size. Bioaccumulation and Food Chain Modeling involve assumptions and uncertainty including: Linear assumption of bioaccumulation and selection of bioaccumulation factors; Other model inputs such as: Home range size, Dietary percentages, Body Weights, Ingestion Rate; Literature data on effects, Use of No Observed Adverse Effects Level (NOAEL) or Lowest Observed Adverse Effects Level (LOAEL) as a decision point. Toxicity testing where employed brings its own set of assumptions and interpretation that are subject to uncertainty. These include: Use of single organism, Correlation (or lack thereof) with Contaminants of Concern, Contaminant mixtures, and Reference area selection. Keywords: Ecotoxicology, Risk Assessment, Ecology

Toxicity study of silica nanoparticles following 94-day repeated oral administration in Sprague Dawley rats.

This study was designed to investigate the toxic response of Sprague Dawley (SD) rats following oral administration of different doses of silica nanoparticles (SiNPs) for 94 consecutive days, as well as the recovery after 30 days of withdrawal. Rats were orally administered SiNPs at dosages of 0, 125, 250, and 500mg/kg /day once a day for 94 continuous days. By the end of the study, there were no fatalities in any of the experimental animals that received SiNPs orally. Under the tested doses, no adverse effects related to SiNPs treatment were observed in a comprehensive assessment of several dimensions, including clinical signs, body weight changes, food consumption, hematological parameters, blood biochemical indices, urinalysis, organ weights and coefficients, and gross and histopathology. Based on the current study results, the No Observed Adverse Effect Level (NOAEL) for repeated oral administration of SiNPs in rats for 94 consecutive days was designated as 500mg/kg/day.

Safety assessment of (S)-Equol: Subchronic toxicity study in Sprague Dawley Rats

(S)-Equol is a chemically synthesized nutraceutical compound and its consumption provides several health benefits for humans. The new nutraceutical, enantiopure (S)-Equol was studied for acute and sub-chronic toxicity in Sprague Dawley Rats. The oral acute toxicity study showed that (S)-Equol is safe > 2000–5000 mg/kg body weight and it classified into GHS category 5/Unclassified. The repeated dose administration of (S)-Equol at dose levels of 20, 60, and 160 mg/kg body weight for 14 days and 250, 500, and 1000 mg/kg body weight for 90-consecitve days. The 14 days repeated-dose toxicity study showed no adverse effects in Sprague Dawley rats. The 90-day repeated dose toxicity study showed a reduction in body weight gain than that of control group. No treatment-related contrary effects were perceived on haematology, clinical chemistry, coagulation, urine parameters analysed, organ weights (absolute and relative), neurological and ophthalmological examination. No treatment-related abnormal gross pathological findings were obtained from gross necropsy. However, as a treatment-related effect, a significant decrease in cholesterol levels for 14 and 90 days of repeated dose administration was observed, which is considered as a pharmacological class effect of the (S)-Equol. In comparison to the corresponding vehicle control group, the high dose treatment group for both sexes showed no treatment-related histopathological abnormalities. For female rats, the no-observed-adverse-effect-level (NOAEL) was 250 mg/kg/day and for male rats, the lowest-observed-adverse-effect level (LOAEL) was 250 mg/kg/day.

Inhibition of Escherichia coli Cell-Free β-Galactosidase Activity by Binary Mixtures of Water-miscible Solvents

The inhibitory effects of ethanol-dimethylsulfoxide (DMSO) and ethanol-N,N-dimethylformamide (DMF) binary mixtures on the activity of cell-free β-galactosidase from Escherichia coli were assessed. The concentration-response relationships of the individual solvent and the mixtures were fitted to a Gormpertz model to estimate the median inhibitory concentrations (EC50) and No-Observable-Effect-Concentration (NOEC) thresholds. The EC50 values estimated are 29.246 ± 2.986% (ethanol), 28.112 ± 0.471% (DMSO), and 18.244 ± 0.674% (DMF). The NOEC values are 11.265 ± 1.121% (ethanol), 6.4047 ± 0.564% (DMSO), and 1.897 ± 0.427% (DMF). The order of inhibitory effects is DMF > DMSO > ethanol. The mixture NOEC values ranged from 10.081% (6:4 ethanol-DMSO mixture) to 13.619% (9:1 ethanol-DMSO mixture). In the case of ethanol-DMF mixtures, NOEC values ranged from 6.843% in 6:4 ethanol-DMF mixture to 10.599% in 9:1 ethanol-DMF mixture. All solvent mixtures with higher EC50 and NOEC values are less inhibitory than the individual DMSO and DMF. The inhibitory effects of the ethanol-DMSO and ethanol-DMF binary mixtures were predicted using the concentration addition (CA) model, toxic index (TI) and model deviation ratio (MDR). The TI for the ethanol-DMSO mixtures ranged from 1.076 ± 0.046 to 1.142 ± 0.032, while that of ethanol-DMF ranged from 1.027 ± 0.015 to 1.136 ± 0.024. These values are marginally higher than 1; thus, the combined effect is considered additive. The study provides fundamental information on the sub-inhibitory concentrations of ethanol, DMSO, and DMF, or their mixtures, for use in the permeabilization of E. coli cells for a β-galactosidase activity assay.

Inhalation Exposure to Cross-linked Polyacrylic Acid Induces Pulmonary Disorders.

Organic polymers, widely used in food, daily necessities, and medicines, include cross-linked polyacrylic acid (CL-PAA), which has been reported to induce severe lung disease. While previous studies mainly used intratracheal instillation, our research focused on inhalation exposure to corroborate these findings. We conducted 5-day (short-term) and 13-week (subchronic) inhalation exposure studies with CL-PAA. In the short-term study, male F344 rats inhaled CL-PAA at 0.2, 2.0, or 20mg/m³ for 6hours/day over 5 days. Rats were dissected 3 days and 1 month post-exposure. In the subchronic study, rats inhaled CL-PAA at 0.2 or 2.0mg/m³ for 6hours/day, 5 days/week for 13 weeks, with dissections from 3 days to 6 months post-exposure. To investigate the mechanism of pulmonary disorders, an additional short-term study with 20mg/m³ CL-PAA included intraperitoneal injections of the antioxidant N-acetylcysteine (NAC) (200mg/kg) with dissection the day after exposure. Short-term exposure led to concentration-dependent increases in neutrophil influx, cytokine-induced neutrophil chemoattractant (CINC), total protein, lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF), and heme oxygenase-1 (HO-1) in lung tissue. Histopathology showed concentration-dependent neutrophil infiltration. Subchronic exposure caused persistent increases in BALF total protein and lung HO-1, with ongoing neutrophil infiltration and fibrosis. NAC administration reduced neutrophils, total protein, LDH, and CINC in BALF, and HO-1 in lung tissue, improving histopathological findings. Inhalation of CL-PAA caused concentration-dependent lung inflammation and persistent fibrosis. The no observed adverse effect level (NOAEL) for chronic pulmonary disorders was 0.2mg/m³. Oxidative stress linked to CL-PAA-induced inflammation was mitigated by NAC administration.

Are Biobased Microfibers Less Harmful than Conventional Plastic Microfibers: Evidence from Earthworms.

Biobased plastics are sometimes promoted as "environmentally friendly" compared to their conventional petrochemical-based counterparts, but their ecotoxicity is only partially understood. Biobased fibers are widely used in clothing and wet wipes and can accumulate in soils through the application of biosolid fertilizers. This study examined the lethal thresholds and sublethal toxicity of chemically characterized, additive-free, biobased (viscose and lyocell) compared to petrochemical-based (polyester) fibers on the key ecosystem engineer, Esenia fetida. Viscose and lyocell had LC20 values of 14.00 and 22.66 mg·L-1, respectively, and no observed effect concentrations (NOEC) of 0-2.8 mg·L-1 (72 h, OECD TG207 filter paper method), while for polyester these were LC20 15.6-31.3 mg·L-1 and NOEC 0-15.6 mg·L-1. Following 28 days of exposure to soils (OECD TG222) contaminated with environmentally relevant concentrations (100 mg kg-1), viscose significantly reduced the mass of progeny compared to polyester. Earthworms exposed to lyocell had a marginal growth reduction (-18%; compared to -11% to -13% in other treatments) linked to increased bioturbation activity. The biobased fibers examined here have greater acute toxicity at high concentrations and broadly similar sublethal effects on E. fetida compared to polyester. Our study highlights the importance of detailed testing before advocating specific materials as plastic alternatives/substitutes to conventional plastics.

A phase I study assessing the safety and tolerability of SPL84, an inhaled antisense oligonucleotide for treatment of cystic fibrosis patients with the 3849 +10kb C->T

BackgroundAntisense Oligonucleotides (ASOs) are small synthetic nucleic acid molecules able to bind specific sequences within target Ribonucleic Acid (RNA) molecules. SPL84 is an ASO drug developed for treatment of cystic fibrosis (CF) patients carrying the 3849 + 10 kb C->T Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) splicing mutation. The 3849 + 10 kb C->T variant leads to inclusion of cryptic exon harboring stop codon leading to the production of truncated non-functional CFTR proteins. in vitro, SPL84 treatment results in splicing modulation, which leads to an increase of correctly spliced CFTR RNA and higher levels of functional CFTR proteins. MethodsSPL84 was tested in a blinded, placebo-controlled phase 1 study in thirty two (32) healthy volunteers (HVs), each received a single dose of either SPL84 or placebo by inhalation. A total of 8 participants were randomized to each of the 4 escalating cohorts in a 3:1 ratio (active: placebo). Safety and tolerability were evaluated by monitoring adverse events (AEs), vital signs, physical exam findings, spirometry, electrocardiograms (ECG), and analyses of safety laboratories. Blood samples were obtained periodically over 24 h for measurement of systemic exposure. ResultsThere were no significant changes from baseline in vital signs, clinical laboratory values, ECG, physical examination, or pulmonary function. There were no Serious Adverse Events (SAEs) in the study, and there were no significant adverse events. The systemic exposure to SPL84 was low and tended to be dose dependent. The exposure, expressed in terms of area under the curve to infinity (AUCinf), at the no observed adverse effect level (NOAEL) in 9-week toxicological mice study was 7.51 µg/ml*hrs, which is ∼20 times higher than the exposure at the 160 mg dose (444 ng/ml*hrs). ConclusionsSPL84 was safe and well-tolerated when administered as a single inhaled dose to HVs at doses up to 160 mg, with minimal systemic exposure. There were no safety issues observed, no SAEs, no significant related AEs, and, importantly, no significant effect on pulmonary function. The successful completion of the study enabled the initiation of multi-dosing of CF patients in a phase 2 clinical study.

Toxicological evaluation of LivLonga®, a polyherbal combination, in rodents

There has been keen interest on herbs and phytoconstituents with hepatoprotective property to help restore healthy liver function. Ayurveda, the ancient Indian traditional system of medicine mentions about Curcuma longa, Garcinia indica and Piper nigrum which are reported to have hepatoprotective activity. Apart from supporting metabolism, liver plays pivotal role in numerous bodily processes, immune functions to digestion, detoxification, and storage of nutrients. Factors such as sedentary lifestyle, viral infections, drugs/chemicals, high calorie diet, excess intake of alcohol etc have adverse impact on normal functioning of liver. Development of novel herbal combination with standards of safety and efficacy can help manage liver ailments and protect liver health. LivLonga® is a polyherbal combination of scientifically validated ingredients- curcuminoids, garcinol and piperine to support healthy liver function. The present work was conducted to evaluate toxicity of LivLonga® using in vivo models when administered orally. The acute, subacute, and subchronic toxicity studies were carried out in accordance with the test guidelines established by the Organization for Economic Cooperation and Development. A single-dose acute oral toxicity produced no toxic effects after 14 days of treatment. Four-week (subacute) and 3-months (subchronic) oral toxicity studies were conducted and observed no abnormal clinical signs, no alterations in the body weight, hematology and biochemical parameters or gross and histopathological changes. Thus, oral administration of LivLonga® showed no signs of toxicity when dosed orally to rats, with a no observed adverse effect level (NOAEL) of 600 mg/kg/day.

Study of combined multiple exposure and reproductive / developmental toxicity of 2-ethylhexanoic acid by screening method

Introduction. According to the normative and methodological documents of the Russian Federation, chemicals introduced into economic activities are subject to mandatory toxicological assessment and hygienic regulation. To substantiate the value of the hygienic standard of 2-ethylhexanoic acid, the production of which is planned in the country, additional test on its reproductive toxicity was required. The aim of the research was to determine the no-observed adverse effect levels of the 2-ethylhexanoic acid for maternal and reproductive toxicities in combined multiple exposure and the reproduction/developmental toxicity screening test (OECD 422). Materials and methods. The study was performed in accordance with the requirements of the OECD Test Guideline 422 «Combined repeated dose toxicity study with the reproduction/developmental toxicity screening test». Results. During the experiment no animal deaths or clinical symptoms of the toxic effect of 2-ethylhexanoic acid were observed at all tested doses (250, 500 and 1000 mg/kg b.w.). The assessment of behavioural responses using the open field method showed no differences in animals from experimental and control group. Histological examination indicated the acid at doses of 500 and 1000 mg/kg b.w. to cause significant changes in bladder (increased sclerosis in the submucosa), lungs (increased proportion of emphysematous altered parenchyma), adrenal gland (increased cell alterations and lipomatous inclusions), thyroid gland (increased loci of interfollicular tissue) in males and females’ rats. The total weight of offspring in the experimental groups was found to be statistically dose-dependent reduced on days 4 and 13 after birth compared with the control. Limitations. The study had no limitations. Conclusion. 2-Ethylhexanoic acid has no effect on the reproductive function in experimental animals. Developmental toxicity, expressed in a decrease in the total weight of offspring, was observed at the level of general toxic effects and is not specific. NOAELs were established at the level of 250 mg/kg b.w. for general toxic effect, > 1000 mg/kg b.w. for reprotoxic effect.

Subchronic Toxicity Evaluation of Dietary Administration of a Fungal Biomass From Rhizomucor pusillus.

Fungal-derived food products align with sustainable food supply principles and offer a sustainable and nutritious option for consumers. Rhizomucor pusillus strain CBS 143028 has emerged as a candidate food ingredient. Fermentation of R. pusillus CBS 143028 results in a mycelium biomass mainly comprising fungal proteins, cell wall components, and micronutrients. Although R. pusillus has a history of safe use in the production of food enzymes and in traditional fermented foods, the fungal biomass obtained after fermentation of R. pusillus CBS 143028 is considered a novel food and requires a thorough safety assessment. To this end, a 90-day oral toxicity study was conducted in which Wistar rats (10/sex/group) were provided diets containing 0, 100,000, 200,000, or 300,000 ppm of R. pusillus mycelium. Standard toxicity study parameters as given in OECD Test Guideline 408 were examined. The mean achieved dosages of R. pusillus mycelium were 6398, 12,738, or 19,668 mg/kg body weight/day for males and 7235, 14,949, or 22,461 mg/kg body weight/day for females in the low-, mid-, and high-dose groups, respectively. Although statistically significant differences were reported, these effects were not considered biologically relevant or test article-related due to atypical values in the control groups, the lack of a dose response relationship, or were attributed to normal biological variation. Thus, the no-observed-adverse-effect level (NOAEL) was established at 300,000 ppm (corresponding to 19,668 and 22,461 mg/kg body weight/day for males and females, respectively), the highest concentration tested.

Aquatic toxicity and ecological risk of bisphenol B, and comparison with those of bisphenol A

2,2-bis(4-hydroxyphenyl)butane (BPB), one of the 2,2-bis(4-hydroxyphenyl)propane (BPA) alternatives, has not received sufficient attention so far due to the limited environmental concentration and toxicological data available. In this study, the acute toxicity of BPB was investigated using three aquatic organisms, i.e., Tetradesmus obliquus, Daphnia magna and Danio rerio. It was showed that Daphnia magna was the most sensitive organism with a half effective concentration of 3.93 mg/L. Subsequently, Daphnia magna was exposed to BPB solutions for 21 days to explore its chronic toxicity. Results indicated that BPB restricted the body length of parent Daphnia magna and reduced the total number of broods and neonates. The no-observed effect concentration of BPB to Daphnia magna was as low as 0.01 mg/L, which was two orders of magnitude lower than that of BPA (0.86–5.00 mg/L). Furthermore, the ecological risk of BPB was quantitatively assessed using a risk quotient (RQ) method. The RQ values of BPB ranged from 0.003 to 0.914, with the mean of 0.197. BPB posed a moderate risk at most sampling sites, while BPA posed a low ecological risk with RQ < 0.1 at nearly all the sampling sites. Hence, environmental monitoring and management should also be focused on BPB contamination.

Dermal toxicity studies of 1,2-benzisothiazolin-3-one (CAS number: 2634-33-5) in Sprague-Dawley rats

Biocides are used as preservatives in various household products, and 1,2-benzisothiazolin-3-one (BIT) is one of the popular chemicals. Therefore, BIT is highly likely to be exposed to human skin, necessitating dermal toxicity evaluation. In this study, we aimed to investigate dermal toxicity, eyes and skin irritation, and skin sensitization of BIT. All studies were conducted according to the Organisation for Economic Co-operation and Development testing guidelines. In acute dermal toxicity using rats, no treatment-related responses were observed at the highest dose (2000 mg/kg). A 28-day repeated dermal toxicity study at 1, 4, and 12 mg/kg/day showed transient local skin irritation lesions, including erythema, exfoliation, and crust formation. Based on no systemic effects, the no observed adverse effect level (NOAEL) of BIT of the 28-day repeated dermal toxicity study was determined to be 12 mg/kg/day. Eye and skin irritation tests showed that BIT is a strong irritant and corrosive to the eyes and a mild irritant to the skin. However, BIT showed no skin sensitization reactions in a local lymph node assay. These dermal toxicity studies can provide valuable information for the risk assessment of BIT.

Evaluation of the chronic oral toxicity of the classical ancient prescription Kai-Xin-San

Ethnopharmacological relevanceThe Kai-Xin-San (KXS), as an ancient classic prescription, has been used for the treatment of amnesia for thousands of years. Modern clinical and non-clinical pharmacological studies have found that it has significant therapeutic effects on dementia and depression, but there are relatively few studies on its safety. Aim of the studySubacute and chronic toxicity studies were conducted to investigate the symptoms, severity, target organs, development and recovery of toxic reactions, as well as the toxic dose. These studies provide technical data for ensuring the safety of KXS. Materials and methodsIn the sub-acute toxicity study, rats were orally administered KXS at doses of 0.80, 1.61, 3.22, and 6.43 g/kg body weight for a duration of 4 weeks. In the chronic toxicity study, rats were orally administered KXS at doses of 0.27, 0.81, and 2.43 g/kg body weight for a duration of 26 weeks, and a withdrawal study was conducted for a period of 4 weeks after the treatment.The rats were observed daily for clinical signs and mortality. Changes in body weight, food consumption, and water consumption were periodically monitored. Additionally, urinalysis results, hematological and biochemical parameters, relative organ weights, and pathology were monitored at specific observation time points. ResultsIn the sub-acute toxicity study, necropsy of dead and moribund rats revealed evident distension and swelling of the gastrointestinal tract, as well as thinning of the intestinal wall. The main adverse reactions observed included flatulence, piloerection, abnormal breathing sounds, and emaciation. Doses of 1.61 g/kg and below did not cause animal death. The gastrointestinal system is the main target organ of toxicity. In the chronic toxicity study, the no-observed-adverse-effect-level (NOAEL) of KXS was 0.27 g/kg, and its toxic effects were primarily concentrated in the gastrointestinal system. This led to secondary pathological changes in the immune system, hematopoietic system, and heart, suggesting that relevant indicators should be monitored when large doses are used clinically for an extended period of time. ConclusionsDuring the rodent toxicity evaluation, severe gastrointestinal damage was observed when KXS, powdered with crude drugs, was administered. The NOAEL for rats was found to be 0.27 g/kg/day.

Toxicodynamics of cadmium in the green mussel Perna viridis (Linnaeus, 1758) using bioenergetic and physiological biomarkers.

This study evaluated the toxicity of cadmium (Cd) on the green mussel Perna viridis, aiming to identify toxicological endpoints and investigate its responses across physiological, bioenergetic, and biochemical parameters. The 96-hour LC50 value for Cd in P. viridis was 3.03 ± 0.12 mg L-1, with a 95% confidence interval of 2.35-3.91 mg L-1. Chronic toxicity tests revealed a No Observable Effect Concentration (NOEC), Lowest Observable Effect Concentration (LOEC), and chronic toxicity values of 0.20, 0.37, and 0.29 mg L-1, respectively. Cadmium accumulation in treated mussels increased 46- to 215-fold compared to the control group. Superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase levels in exposed mussels exhibited a significant increase compared to the control group. The redox index ratio, acetylcholinesterase activity, and lysosomal membrane stability decreased with increasing exposure concentrations. Levels of reduced and oxidized glutathione, glutathione reductase, lipid peroxidation, and metallothionein-like proteins increased in exposed mussels. Clearance rate, respiration rate, and excretion rate decreased in a dose-dependent manner. Protein, carbohydrate, and lipid levels decreased with increasing exposure concentration (p < 0.001). Mitochondrial electron transport system activity increased, while cellular energy allocation (p < 0.001) and scope for growth decreased in a dose-dependent manner (p < 0.01). The significant increase in antioxidants suggests heightened oxidative stress in mussels under Cd exposure. The physiological activities of the mussels were severely affected, ultimately leading to a reduced scope for growth. The toxicological data generated in this study contribute to the development of seawater quality criteria for the metal Cd.

7372 Anti-Corticotropin-Releasing Hormone (CRH) Monoclonal Antibody HBM9013 For The Treatment Of Congenital Adrenal Hyperplasia (CAH) And Polycystic Ovarian Syndrome (PCOS)

Abstract Disclosure: H. Pan: None. L.L. Liu: None. Q. Lv: None. F.G. Grosveld: None. D. Drabek: None. R.V. Haperen: None. X. Wang: None. Y. He: None. Y. Wang: None. J. Huang: None. J. Lee: None. G. Zhang: None. J.J. Rong: None. H.V. Chen: None. J.A. Majzoub: Advisory Board Member; Self; Chair of SAB of Harbour BioMed Alpha Therapeutics, which owns the rights of HBM9013.. Stock Owner; Self; Equity Owner of Harbour BioMed Alpha Therapeutics, which owns the rights of HBM9013.. J.J. Zhao: None. Anti-Corticotropin-Releasing Hormone (CRH) Monoclonal Antibody HBM9013 for the Treatment of Congenital Adrenal Hyperplasia (CAH) and Polycystic Ovarian Syndrome (PCOS). Abstract Congenital Adrenal Hyperplasia (CAH) is a rare autosomal recessive genetic disease due to mutation of CYP21A2 which leads to deficiency of 21-Hydroxylase enzymatic activity. Classical CAH patients are born with life-threatening deficiency of glucocorticoid (GC) and mineralocorticoid. Due to this enzymatic block and the lack of negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis by GC, the adrenal gland produces excessive amounts of androgen which result in masculinized genitalia and virilization. The current standard care is supraphysiological doses of GC, which are difficult to balance between excess GC exposure and excess androgen secretion. Too little GC does not suppress production of androgen sufficiently and too much GC leads to Cushing Syndrome (CS). Previous work found that corticotropin-releasing hormone (CRH) is absolutely required for activation of the HPA axis during loss of GC negative feedback, via adrenocorticotropic hormone (ACTH) (1), which is necessary for production of adrenal androgens (2). We report here the development of Anti-CRH humanized monoclonal antibody HBM9013 (PR302334-24) for the treatment of CAH. HBM9013 binds to CRH with high affinity and neutralizes its signaling through both CRH Receptor 1 (CRHR1) and CRH Receptor 2 (CRHR2) in vitro. HBM9013 shows in vivo activities in two preclinical models. It blocks restraint stress-induced increases in plasma ACTH and corticosterone in mouse and rat. Mouse ACTH and Corticosterone were reduced from 210 ± 63 pg/ml to 27 ± 8 pg/ml (Mean ± SD, p = 5.2*10-6; IgG1 Control Group = 6 mice; HBM9013 Group = 8 mice) and from 303 ± 28 ng/ml to 57 ± 15 ng/ml (Mean ± SD, p = 6.2*10-[1][1]; IgG1 Control Group = 6 mice; HBM9013 Group = 8 mice), respectively. It also markedly reduces the constitutive, extremely elevated plasma ACTH levels in Mrap-knockout mice from 3847 ± 240 pg/mL to 1080 ± 302 pg/mL (Mean ± SD, n = 5 independent experiments, p = 2.3*10-7). HBM9013 has excellent CMC characteristics with ∼5 g/L titer and ∼80% yield. HBM9013 also has an excellent safety profile with no-observed-adverse-effect-level (NOAEL) of 150 mg/kg in weekly dosing for five doses in both rat and cynomolgus dose-ranging-finding (DRF) toxicology studies. HBM9013 is formulated up to 150 mg/ml as a weekly to monthly subcutaneous injection for ease of administration and compliance for CAH patient. HBM9013 could be a next generation therapy for CAH, in combination with a low physiological dose of GC that would avoid CS. Since ∼50% of Polycystic Ovarian Syndrome (PCOS) androgens may be of adrenal origin, we believe that HBM9013 could also be indicated for PCOS. References(1)Muglia LJ et al. J Clin Invest. 2000. 105:1269-77.(2)Weber A et al. Clin Endocrinol. 1997. 46:431-7. Presentation: 6/1/2024

Neonicotinoid pesticides: evidence of developmental neurotoxicity from regulatory rodent studies.

Neonicotinoids are the most widely used class of insecticides in the United States (U.S.). and the world. Consistent with their high use and persistence, neonicotinoids are often found contaminating drinking water and food. They are also detected in human urine, breast milk, amniotic and cerebrospinal fluids, as well as the brains of treated rodents. Neonicotinoids were once thought to pose little neurotoxic risk to humans, but a growing body of research challenges that assumption. In this study we provide the first comprehensive assessment of unpublished rodent developmental neurotoxicity (DNT) studies on five neonicotinoids that were submitted to the U.S. Environmental Protection Agency (EPA) by neonicotinoid manufacturers. Groups of female rats were administered three different doses of a neonicotinoid during pregnancy and lactation, and their offspring subjected to various neurological tests and brain measurements. We identified nicotine-like effects such as reduced brain size, indicative of neuronal cell loss. Statistically significant shrinkage of brain tissue was observed in high-dose offspring for five neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam. Two brain regions reduced in the rodent studies-the corpus callosum and caudate-putamen-tend to be smaller in people diagnosed with attention-deficit hyperactivity disorder (ADHD), and in children of mothers who smoked during pregnancy, suggesting a possible link between perinatal neonicotinoid exposure and ADHD. A decreased auditory startle reflex was reported for acetamiprid at all doses and was statistically significant in the mid- and high-dose offspring, and for clothianidin in juvenile high-dose females. No mid- or low-dose brain morphometric data were submitted for acetamiprid, imidacloprid, or thiacloprid. Thiamethoxam mid- and low-dose brain morphometric data were provided to EPA upon request. Only partial mid-dose brain morphometry data were submitted for clothianidin, but no low-dose data. Yet despite this lack of data, EPA concluded that only the high-dose brain morphometric effects were treatment-related-setting the mid-dose as the study's No Observed Adverse Effect Level (NOAEL) or failing to find a definitive NOAEL for acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam. We found numerous deficiencies in EPA's regulatory oversight and data analyses. EPA dismissed statistically significant adverse effects, accepted substandard DNT studies despite lack of valid positive control data, and allowed neonicotinoid registrants to unduly influence agency decision-making. We conclude that perinatal exposure to neonicotinoids and their metabolites induces adverse, nicotine-like neurotoxic effects in rodent bioassays, and that the exposure limits set by EPA for human exposure are either not protective or not supported by available neurotoxicity data. We propose regulatory changes to empower EPA to better protect public health from developmental neurotoxins like neonicotinoids.