SARS-CoV-2 Mpro responds to oxidation by forming disulfide and NOS/SONOS bonds.

The main protease (Mpro) of SARS-CoV-2 is critical for viral function and a key drug target. Mpro is only active when reduced; turnover ceases upon oxidation but is restored by re-reduction. This suggests the system has evolved to survive periods in an oxidative environment, but the mechanism of this protection has not been confirmed. Here, we report a crystal structure of oxidized Mpro showing a disulfide bond between the active site cysteine, C145, and a distal cysteine, C117. Previous work proposed this disulfide provides the mechanism of protection from irreversible oxidation. Mpro forms an obligate homodimer, and the C117-C145 structure shows disruption of interactions bridging the dimer interface, implying a correlation between oxidation and dimerization. We confirm dimer stability is weakened in solution upon oxidation. Finally, we observe the protein's crystallization behavior is linked to its redox state. Oxidized Mpro spontaneously forms a distinct, more loosely packed lattice. Seeding with crystals of this lattice yields a structure with an oxidation pattern incorporating one cysteine-lysine-cysteine (SONOS) and two lysine-cysteine (NOS) bridges. These structures further our understanding of the oxidative regulation of Mpro and the crystallization conditions necessary to study this structurally.

Long-term cost-effectiveness of transcatheter mitral valve repair in HF patients with secondary mitral regurgitation.

AIMS: The long-term cost-effectiveness of MitraClip in heart failure patients with secondary mitral regurgitation is still unclear. This study aimed to evaluate the long-term cost-effectiveness of MitraClip added to guideline-directed medical therapy vs. guideline-directed medical therapy alone in heart failure patients with secondary mitral regurgitation from the perspective of the healthcare systems of mainland China, the United Kingdom, Germany, and the United States. METHODS AND RESULTS: A two-stage (decision + Markov) model was built. Health utilities were defined by the New York Heart Association class, heart failure re-hospitalization, and death and were calculated based on the 5 year follow-up results of the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation trial. Direct healthcare costs were derived from the nationally representative data. Future utilities and costs were discounted at country-specific rates. The primary outcome was the lifetime incremental cost-effectiveness ratio. The mean age of the base case in our model was 72.2 years. Over a lifetime horizon, treatment with MitraClip was associated with 829 fewer heart failure re-hospitalizations per 1000 treated patients. The MitraClip treatment was associated with incremental quality-adjusted life-year gains of 0.71, 0.76, 0.78, and 0.78, as well as incremental cost-effectiveness ratios of ¥468 462, £28 910, €26 045, and $71 199 per quality-adjusted life-year for a lifetime horizon in mainland China, the United Kingdom, Germany, and the United States, respectively. In probabilistic sensitivity analysis, 0.2%, 59.4%, 99.6%, and 84.7% of patients were cost-effective in mainland China, the United Kingdom, Germany, and the United States at the country-specific willingness-to-pay thresholds. CONCLUSIONS: MitraClip + guideline-directed medical therapy was cost-effective in heart failure patients with secondary mitral regurgitation in the United Kingdom, Germany, and the United States, but not in mainland China from the perspective of the national healthcare system.

The association between TyG and all-cause/non-cardiovascular mortality in general patients with type 2 diabetes mellitus is modified by age: results from the cohort study of NHANES 1999-2018.

BACKGROUND: The prognostic value of triglyceride-glucose (TyG) index in general type 2 diabetes mellitus (T2DM) patients is still unclear. Therefore, we aimed to determine the associations between TyG and all-cause/cause-specific death in a T2DM cohort and explore whether such associations would be modified by age. METHODS: A total of 3,376 patients with T2DM from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 were selected and divided into the younger group (< 65 yrs) and the older group (≥ 65 yrs). Baseline TyG was calculated and cause-specific mortality status [cardiovascular (CV), cancer, and non-CV] was determined by the NHANES Public-Use Linked Mortality Files through 31 December 2019. Multivariate Cox and restricted cubic spline (RCS) regression models were used to evaluate the association between TyG and all-cause/cause-specific mortality. Interaction between TyG and age to mortality was also evaluated. Sensitivity analyses were performed in patients without cardiovascular disease, chronic kidney disease, or insulin treatment. RESULTS: During a median follow-up of 107 months, 805 all-cause deaths occurred, of which 250 and 144 were attributed to CV and cancer deaths. There was a significant age interaction to the association between TyG and all-cause/non-CV mortality. After fully adjusting for potential confounding factors, higher TyG was associated with an increased risk of all-cause [TyG per unit increase Hazard Ratio (HR) 1.33, 95% Confidence Interval (CI) 1.06-1.66, p = 0.014] and non-CV mortality (TyG per unit increase HR 1.54, 95% CI 1.18-2.01, p = 0.002) only in the younger group, but not in the older group. There was no significant association between TyG and CV/cancer death in the total cohort and two age subgroups. Similar results were found in RCS and sensitivity analyses. CONCLUSION: In a national sample of patients with T2DM in the United States, we found that the association between TyG and all-cause/non-CV death was modified by age. Higher TyG was only associated with an increased risk of all-cause/non-CV only in T2DM patients younger than 65 years old, but not in older patients.

On the error performance and channel capacity of a uniquely decodable coded FSO system over Malaga turbulence with pointing errors.

Our previous work has proved that the uniquely decodable code (UDC) has the ability of enhancing the throughput of a free space optical communication (FSO) system. This paper quantitatively analyzes the error performance and channel capacity of the UDC-FSO system under Malaga turbulence and pointing errors. We first propose the minimum distance of the superimposed patterns (MDSP) approximation to reveal the universal symbol error rate (SER) for UDC-FSO systems. A closed form expression of SER is further deduced for a special case of 2 TXs. Based on the deduced SER, the upper and lower bounds of bit error rate (BER) can be obtained. Additionally, the discrete channel capacity of the UDC-FSO system is defined and deduced according to different superposition patterns, as well as the channel capacity gain. Both simulation and experiment verify the accuracy of the MDSP and SER's expressions. It's also discovered that the channel capacity of the UDC-FSO system is superior to the conventional end-to-end (E2E) link, where maximal channel capacity is limited by the UDC codebooks.

Mix-and-extrude: high-viscosity sample injection towards time-resolved protein crystallography.

Time-resolved crystallography enables the visualization of protein molecular motion during a reaction. Although light is often used to initiate reactions in time-resolved crystallography, only a small number of proteins can be activated by light. However, many biological reactions can be triggered by the interaction between proteins and ligands. The sample delivery method presented here uses a mix-and-extrude approach based on 3D-printed microchannels in conjunction with a micronozzle. The diffusive mixing enables the study of the dynamics of samples in viscous media. The device design allows mixing of the ligands and protein crystals in 2 to 20 s. The device characterization using a model system (fluorescence quenching of iq-mEmerald proteins by copper ions) demonstrated that ligand and protein crystals, each within lipidic cubic phase, can be mixed efficiently. The potential of this approach for time-resolved membrane protein crystallography to support the development of new drugs is discussed.

Exploration on the blended learning reform in organ-systems based curriculum model of the endocrine system / 中华医学教育探索杂志

Since 2016, Binzhou Medical University began to carry out the blended learning reform in the organ-systems based curriculum (OSBC) of the experimental class of clinical medicine. Based on the traditional face-to-face teaching method, the blended learning mode of the integrated course of endocrine system under OSBC has been carried out by using the small private online course (SPOC) of MOOC platform of China universities. Many teaching methods have been adopted and formed, including case-based learning (CBL), problem-based learning (PBL), professional bilingual teaching, scientific research teaching and virtual simulation experiment teaching. The evaluation system for the combination of formative and summary assessment has been also adopted in the whole process to assess the students' academic achievement, and the teaching effect as well. The blended learning mode of the integrated course of the endocrine system under OSBC is still in the exploratory stage. There are some limitations, such as too high requirements for teachers' quality, long preparation time for teaching, and great difficulty in supervising online learning. However, the practice of teaching reform that has been carried out shows that it is effective, feasible, and worth popularizing.

Urinary continence-related structures and intraoperative protective techniques in radical prostatectomy / 现代泌尿外科杂志

Radical prostatectomy (RP) is the standard treatment for patients with early-stage of prostate cancer,but often causes urinary incontinence and other complications, which harm patients’ quality of life. The protection and reconstruction of urinary continence-related structures during the operation are significant approaches to reduce the incidence of urinary incontinence and restore urinary continence. This article reviewed the surgical approaches of radical prostatectomy, anatomy of urinary continence-related structures (bladder neck, functional urethra, supporting structures, nerves and vessels) and the protective skills,hoping to provide reference for the treatment of early-stage prostate cancer.

Likelihood based synchronization algorithms in optical pulse position modulation systems with photon-counting receivers.

Deep space optical communication (DSOC) is becoming a hot topic. Pulse position modulation (PPM) is an effective tool to realize DSOC benefiting from the feature of high sensitivity. In this paper, we analyze 2 × 1 optical PPM systems with photon-counting detectors, where the distance difference between the two links causes asynchronous superpositions at the receiving end. Two synchronization algorithms are proposed to estimate the time offsets of the two links, which are the optimal Global Maximum Likelihood Estimation (GMLE) and the suboptimal Integer Comparison - Fractional Likelihood Estimation (ICFLE). The complexities of the two methods are also compared. In order to measure the two proposed algorithms, the Cramer-Rao bounds (CRB) are derived. According to simulation results, both the two proposed algorithms approach the deduced CRBs. Furthermore, an equivalent experiment is designed to verify the feasibility and effectiveness of the proposed algorithms. It's also indicated that the proposed algorithms may be utilized in practical systems.

Antibiotic resistance of Helicobacter pylori isolated from children in Chongqing, China.

The resistance of Helicobacter pylori (H. pylori) to antibiotics has been increasing worldwide and varies across different geographic areas and times. Limited studies reported the prevalence of antibiotic resistance and its related gene mutations in children in Chongqing, a city located in southwest China. We collected 112 H. pylori strains isolated from gastric biopsies of 156 children at Children's Hospital of Chongqing Medical University and calculated resistance rates of these strains to six antibiotics. The A2143G and A2142G mutations in 23S rRNA gene, which are related to clarithromycin resistance, and Asn87 and Asp91 mutations in gyrA gene, which are related to levofloxacin resistance, were investigated in 102 strains. The resistance rates to clarithromycin, metronidazole, and levofloxacin were 47.3% (53/112), 88.4% (99/112), and 18.8% (21/112), respectively. No resistance to amoxicillin, tetracycline, and furazolidone was observed. Dual and triple resistance percentages were 37.5% (42/112) and 10.7% (12/112), respectively. The detection rate of A2143G mutation in 23S rRNA gene was 83.3% (40/48). The detection rates of mutations of Asn87 and Asp91 in gyrA gene were 52.6% (10/19) and 36.8% (7/19), respectively. Conclusion: The prevalence of H. pylori resistance to clarithromycin, metronidazole, and levofloxacin was high in children in Chongqing, China. The A2143G mutation was detected in most clarithromycin-resistant strains, and Asn87 and Asp91 of gyrA mutation points were common in levofloxacin-resistant strains. In clinical practice, anti-H. pylori therapy should be individualized based on a susceptibility test.  What is Known: • The resistance of H. pylori to antibiotics changes with the geographic areas and that in Asia the resistance rate is high. • Mutation plays a vital role in antibiotics resistance of H. pylori. What is New: • High resistance rates to single and multiple antibiotics in children of Chongqing, a city located in southwest China, were observed. • Molecular assays showed good conformance with susceptibility test results to direct antibiotic resistance of H. pylori.

Factors affecting recurrent positive RT-PCR results in clinically cured COVID-19 patients: a multicenter study.

The aim of this study was to evaluate factors affecting the recurrence of positive RT-PCR results. By performing a retrospective analysis, we evaluated the clinical data of recurrent positive coronavirus disease 2019 (COVID-19) patients in multiple medical institutions in Wuhan. We recruited COVID-19 patients who were hospitalized from January 1 to March 10, 2020, in three tertiary hospitals in Wuhan, met the discharge criteria and received at least one additional nucleic acid test before leaving the hospital. According to the RT-PCR results, patients were split into a recurrent positive group (RPos group) and a nonrecurrent positive group (non-RPos group). Clinical characteristics, therapeutic schedules and antibody titers were compared between the two groups. AI-assisted chest high-resolution computed tomography (HRCT) technology was applied to investigate pulmonary inflammatory exudation and compare the extent of lung areas with different densities. This study involved 122 COVID-19 patients. There were no significant differences in age, sex, preexisting diseases, clinical symptoms, clinical classification, course of disease, therapeutic schedules or serum-specific antibodies between the two groups. A higher proportion of patients who showed pulmonary inflammatory exudation on HRCT scans were recurrent positive at the time of discharge than other patients (81.6% vs 13.7%, P < 0.01). In addition, the degree of pulmonary fibrosis was higher in the RPos group than in the non-RPos group (P < 0.05). Subpleural exudation at the peripheral edge of the lung and extensive pulmonary fibrosis at the time of discharge represent risk factors for the recurrence of COVID-19.

[Impact of 4-bromobiphenyl ether on the expression of γH2AX in the rat testis].

Objective: To investigate the effects of monobromobiphenyl ether (4-BDE) on the expression of γH2AX in the rat testis, and the possible mechanism of 4-BDE affecting the reproductive function of the male rats. METHODS: Twenty-four SD male rats were randomly divided into 4 groups: control and low-, medium- and high-dose 4-BDE, the control rats treated intragastrically with olive oil, and the animals in the latter three groups with 4-BDE at 50, 100 and 200 mg/kg/d, respectively, all for 30 consecutive days. Then all the rats were killed and the testis tissues harvested for HE staining, examination of the apoptosis of the cells by TUNEL and determination of the expressions of H2AX mRNA and γH2AX by q-PCR and Western blot. RESULTS: HE staining manifested occasional reduction or absence of spermatogonial and Sertoli cells in the seminiferous tubules in the medium- and high-dose 4-BDE groups. Compared with the controls, the rats exposed to 4-BDE showed a significant dose-dependent increase in the apoptosis of the testis tissue (P < 0.05), even more significant in the medium- and high-dose 4-BDE groups than in the low-dose group (P < 0.05). There was a dose-effect relationship in the apoptosis index, but with no statistically significant difference between the medium- and high-dose 4-BDE groups (P > 0.05). The results of q-PCR exhibited no statistically significant difference in the expression level of H2AX mRNA either between the control and 4-BDE-exposed rats (P > 0.05) or among the three 4-BDE groups (P > 0.05). The expression of the γH2AX protein was remarkably higher in the 4-BDE groups than in the control (P < 0.05), but not significantly different among the 4-BDE groups (P > 0.05). CONCLUSIONS: Exposure to 4-BDE at 100 or 200 mg/kg/d damages the structure of seminiferous tubules, increases the apoptosis of testicular cells, significantly up-regulates the expression of the γH2AX protein, and consequently increases DNA double-strand breaks (DSB) in the rat testis. The apoptosis of testicular cells may be related to DSB./.

Clusterin suppresses spermatogenic cell apoptosis to alleviate diabetes-induced testicular damage by inhibiting autophagy via the PI3K/AKT/mTOR axis.

BACKGROUND INFORMATION: Diabetes-induced testicular dysfunction is characterised by abnormal apoptosis of spermatogenic cells, but the underlying mechanism is poorly understood. This study aimed to investigate the roles of clusterin (CLU) in testicular damage associated with diabetes pathogenesis, as well as the molecular mechanism. A rat diabetes model was established using streptozocin, and the mouse spermatogenic cell line GC-1 spg was treated with high glucose as a cellular model. CLU was overexpressed in GC-1 spg cells, followed by detection of serum testosterone, cell proliferation, cell apoptosis and autophagy. RESULTS: CLU expression was significantly reduced and LC3 expression was elevated in testis tissues in the rat diabetes model and high glucose-treated GC-1 spg cells. High glucose led to suppressed viability, enhanced apoptosis, reduced Bcl-2 expression, elevated Bax expression and cleavage of Caspase-3/-9 in GC-1 spg cells, and these effects were abrogated by CLU overexpression. Additionally, CLU overexpression repressed LC3 and Beclin-1 expression, reduced the LC3II/LC3I ratio and promoted p62 expression in GC-1 spg cells in the presence of high glucose, and these effects were all mitigated by rapamycin treatment. Inhibition of PI3K/AKT/mTOR signalling with LY294002 activated autophagy in CLU-overexpressing GC-1 spg cells under high glucose conditions. CLU overexpression repressed autophagy and alleviated testicular damage in diabetic rats, which was also abrogated by LY294002 treatment. CONCLUSIONS: CLU expression is suppressed during diabetes-induced testicular damage, whereas CLU overexpression alleviates diabetes-induced testicular damage by activating PI3K/AKT/mTOR signalling to inhibit autophagy and further repress spermatogenic cell apoptosis.

[Protective effect of taurine against formaldehyde-induced male reproductive toxicity in adult male rats].

OBJECTIVE: To study the effect of taurine on the reproductive toxicity damage induced by formaldehyde (FM) in adult male rats. METHODS: Forty-eight SD adult male rats were equally randomized into a normal control, an FM poisoning (FMP), a taurine intervention (TI), and an TI+FMP group. The control rats were given normal diet and gavage of saline, the rats of the FMP group treated intraperitoneally with FM at 10 mg/kg qd alt, those of the TI group intragastrically with taurine at 100 mg/kg qd, and those of the TI+FMP group with both FM and taurine at the above doses. After 30 days of treatment, the blood of the abdominal cardinal vein of the rats was extracted for measurement of the levels of serum hormones, the body weight, testis weight and testicular coefficient obtained, the testis tissue subjected to HE staining, and the expressions of Bcl-2 and Bax determined by Western blot. RESULTS: There were no statistically significant differences among the four groups of rats in the body weight, testis weight or testicular coefficient (P > 0.05). The rats in the FMP group showed obviously decreased testicular spermatogenic cells and disordered layers and loose structure of seminiferous tubules, which were basically restored to normal after taurine intervention. Compared with the normal controls, the animals of the TI group exhibited no significant abnormality, but those of the FMP group presented markedly reduced levels of serum T, LH and FSH (P < 0.05), and dramatically increased level of Gonadotropin-releasing hormone (GnRH) (P < 0.01). The levels of serum hormones were all significantly improved (P < 0.05) and that of the apoptotic protein Bax basically returned to normal (P < 0.05) after taurine intervention. CONCLUSIONS: Taurine has a certain protective effect against male reproductive toxicity caused by formaldehyde.

[Ultrasonographic and clinical features of common testicular germ cell tumors in children].

OBJECTIVE: To study the ultrasonographic manifestations and clinical features of common pediatric testicular germ cell tumors (TGCT) in children. METHODS: We retrospectively analyzed the laboratory, ultrasonographic and clinical data on 92 children with TGCT diagnosed in Shanghai Children's Hospital from March 2013 to January 2019, and investigated the values of the serum alpha-fetoprotein (AFP) level and maximum diameter of tumors in the diagnosis of benign and malignant tumors using the ROC curve. RESULTS: Of the 92 cases of pediatric TGCT, 64 (69.6%) were pathologically confirmed as benign tumors, including 40 cases of teratoma (62.5%), 18 cases of epidermoid cyst (28.1%) and 6 cases of dermoid cyst (9.4%), and the other 28 (30.4%) as malignant neoplasms, including 26 cases of yolk sac tumor (YST, 92.9%) and 2 cases of mixed germ cell tumor (MGCT, 7.1%). Ultrasonography showed that 62.5% of the teratomas were cystic-solid mixed (25/40) and 32.5% solid masses (12/40), that 33.3% of the epidermoid cysts exhibited a typical sign of "onion ring" (6/18) and 22.2% that of capsular calcification (4/18), and that 42.3% of the YSTs displayed isoechoic (11/26), 30.9% hypoechoic (8/26) solid masses without calcium and 26.9% cystic anechoic lesions (7/26). Color Doppler blood flow imaging manifested abundant blood flow signals in most of the YSTs (25/26, 96.2%) but none in either the epidermoid or the dermoid cysts. The area under the ROC curve (AUC) of the serum AFP value was 0.985, with an optimal cutoff value of 124.2 ng/ml, and the sensitivity and specificity of AFP in the diagnosis of benign and malignant tumors were 92.9% and 93.7%, respectively. The AUC of the maximum diameter of the tumors was 0.796, with an optimal cutoff value of 2.7 cm, and the sensitivity and specificity of the maximum diameter of the tumors in the diagnosis of benign and malignant neoplasms were 57.1% and 93.7%, respectively. CONCLUSIONS: Ultrasonographic images have different characteristic manifestations for different pathological types of pediatric TGCT. Pediatric TGCT has a good prognosis and radical orchiectomy should be considered for the treatment of the tumors with serum AFP ≥ 124.2 ng/ml and a diameter ≥ 2.7 cm.

Advances in long-wavelength native phasing at X-ray free-electron lasers.

Long-wavelength pulses from the Swiss X-ray free-electron laser (XFEL) have been used for de novo protein structure determination by native single-wavelength anomalous diffraction (native-SAD) phasing of serial femtosecond crystallography (SFX) data. In this work, sensitive anomalous data-quality indicators and model proteins were used to quantify improvements in native-SAD at XFELs such as utilization of longer wavelengths, careful experimental geometry optimization, and better post-refinement and partiality correction. Compared with studies using shorter wavelengths at other XFELs and older software versions, up to one order of magnitude reduction in the required number of indexed images for native-SAD was achieved, hence lowering sample consumption and beam-time requirements significantly. Improved data quality and higher anomalous signal facilitate so-far underutilized de novo structure determination of challenging proteins at XFELs. Improvements presented in this work can be used in other types of SFX experiments that require accurate measurements of weak signals, for example time-resolved studies.

The Issue of Recurrently Positive Patients Who Recovered From COVID-19 According to the Current Discharge Criteria: Investigation of Patients from Multiple Medical Institutions in Wuhan, China.

The current discharge criteria for COVID-19 require that patients have 2 consecutive negative results for reverse transcription polymerase chain reaction (RT-PCR) detection. Here, we observed that recurrent positive RT-PCR test results in patients with 3 consecutive negative results (5.4%) were significantly decreased compared with those in patients with 2 consecutive negative results (20.6%); such patients reported positive RT-PCR test results within 1 to 12 days after meeting the discharge criteria. These results confirmed that many recovered patients could show a positive RT-PCR test result, and most of these patients could be identified by an additional RT-PCR test prior to discharge.

[Reproductive toxicity of PBDE in males: Advances in studies].

Polybrominated biphenyl ether (PBDE) is a kind of brominated aromatic hydrocarbon commonly used as a flame retardant and now considered as one of the persistent organic pollutants, which generally exists in the environment and organisms. Studies have shown that PBDEs have an endocrine disrupting effect, neurotoxicity, developmental toxicity, reproductive toxicity, and the ability of inducing reproductive toxicity in men by reducing semen quality, affecting testis germ cells and interfering with reproductive hormone levels. Although PBDEs have been banned in some countries, they do exist in our environment. Therefore, more studies are needed to reveal their potential toxicity and mechanisms, so as to monitor, predict and prevent their pollution. This review focuses on the male reproductive toxicity of PBDEs.

Towards high throughput GPCR crystallography: In Meso soaking of Adenosine A2A Receptor crystals.

Here we report an efficient method to generate multiple co-structures of the A2A G protein-coupled receptor (GPCR) with small-molecules from a single preparation of a thermostabilised receptor crystallised in Lipidic Cubic Phase (LCP). Receptor crystallisation is achieved following purification using a low affinity "carrier" ligand (theophylline) and crystals are then soaked in solutions containing the desired (higher affinity) compounds. Complete datasets to high resolution can then be collected from single crystals and seven structures are reported here of which three are novel. The method significantly improves structural throughput for ligand screening using stabilised GPCRs, thereby actively driving Structure-Based Drug Discovery (SBDD).

Potential biomarkers for monitoring the toxicity of long-term exposure to atrazine in rat by metabonomic analysis.

1. Herbicide atrazine (ATR) poses harmful effects on human health. The purpose of this study is to study potential biomarkers used for monitoring the toxic effects after chronic exposure to ATR by studying urine metabolites. 2. Rats were assigned into clinical chemistry and metabonomics arms, and each arm was divided into low-dose, high-dose and control groups. ATR was administered to rats along with their feed. At the end of 16, 20 and 24 weeks, clinical parameters and histopathologic changes was assessed to monitor the toxic effects. Twenty-four hour urine samples was analyzed by UPLC-MS, to find the significant alterations in metabolic profiling. 3. The body weight of rats in ATR group was lower than that of control starting from 12th week; abnormal levels of serum biochemistry and histopathologic alterations of organs were found initially from 16th and 20th week, respectively. Five exogenous and five endogenous metabolites were found which showed significant differences between ATR groups and control group at above-mentioned time points. 4. These metabolites may be used as potential indicators to monitor ATR toxicity, and also may provide some clues for understanding the mechanism of toxicity of ATR. The exact relationship between endogenous metabolites and ATR toxicity needs further investigation.