[Effect of mild hypothermia on macrophage polarization in lipopolysaccharide-induced acute lung injury mice].

OBJECTIVE: To investigate the effect of mild hypothermia on macrophage polarization in lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice and to clarify its role in lung injury. METHODS: According to a random number table method, 18 male C57BL/6 mice were divided into sham operation group (Sham group), ALI normothermic model group (NT group) and ALI mild hypothermia treatment group (HT group), with 6 mice in each group. The ALI model in mice was established by the method of tracheal instillation of LPS, and temperature control was administered at 1 hour after surgery. The anus temperature in NT group was kept at 36-38?centigrade, while the anus temperature in HT group was kept at 32-34?centigrade. The target anus temperature in both groups were maintained for 6 hours and then slowly rewarmed to 36-38 centigrade. The Sham group was infused with an equal amount of physiological saline through the trachea without temperature control. After 24 hours of modeling, serum was collected and mice were sacrificed to obtain lung tissue. Pathological changes in lung tissue were observed under light microscopy and semi-quantitative lung injury score was performed. Enzyme linked immunosorbent assay (ELISA) was used to detect the serum levels of interleukins (IL-1ß, IL-10). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to test the indicators of macrophage polarization, such as the mRNA expressions of CD86, IL-6, CD206 and arginase 1 (Arg1) in the lung tissue. The protein expression of M1 macrophage marker inducible nitric oxide synthase (iNOS) and M2 macrophage marker Arg1 were detected by Western blotting. RESULTS: Compared with the Sham group, the NT group appeared significant pulmonary hemorrhage and edema, thickened lung septum, inflammatory cell infiltration, and lung injury score was significantly increased; serum IL-1ß level was significantly elevated; IL-10 level was increased without statistical significance; the expressions of CD86 mRNA, IL-6 mRNA and iNOS protein were significantly elevated, and CD206 mRNA was significantly decreased; the mRNA and protein expressions of Arg1 decreased, but there were no significant differences. Compared with the NT group, the pathological injury of lung tissue in HT group was significantly reduced, and the lung injury score was significantly decreased (4.78±0.96 vs. 8.56±1.98, P < 0.01); serum IL-1ß level was decreased (ng/L: 13.52±1.95 vs. 27.18±3.87, P < 0.01), and IL-10 level was significantly increased (ng/L: 42.59±15.79 vs. 14.62±4.47, P < 0.01); IL-6 mRNA expression was decreased in lung tissue (2-ΔΔCt: 3.37±0.92 vs. 10.04±0.91, P < 0.05), the expression of M1 macrophage markers CD86 mRNA and iNOS protein were significantly decreased [CD86 mRNA (2-ΔΔCt): 0.52±0.16 vs. 1.95±0.33, iNOS protein (iNOS/ß-actin): 0.57±0.19 vs. 1.11±0.27, both P < 0.05], the expression of M2 macrophage markers CD206 mRNA, Arg1 mRNA and Arg1 protein were significantly increased [CD206 mRNA (2-ΔΔCt): 3.99±0.17 vs. 0.34±0.17, Arg1 mRNA (2-ΔΔCt): 2.33±0.73 vs. 0.94±0.23, Arg1 protein (Arg1/ß-actin): 0.96±0.09 vs. 0.31±0.11, all P < 0.05]. CONCLUSIONS: Mild hypothermia can alleviate the inflammatory response and protect lung tissue in ALI mice, which may be related to the inhibition of M1 macrophage polarization and promotion of M2 macrophage polarization.

Structural Similarities and Overlapping Activities among Dihydroflavonol 4-Reductase, Flavanone 4-Reductase, and Anthocyanidin Reductase Offer Metabolic Flexibility in the Flavonoid Pathway.

Flavonoids are potent antioxidants that play a role in defense against pathogens, UV-radiation, and the detoxification of reactive oxygen species. Dihydroflavonol 4-reductase (DFR) and flavanone 4-reductase (FNR) reduce dihydroflavonols and flavanones, respectively, using NAD(P)H to produce flavan-(3)-4-(di)ols in flavonoid biosynthesis. Anthocyanidin reductase (ANR) reduces anthocyanidins to flavan-3-ols. In addition to their sequences, the 3D structures of recombinant DFR, FNR and ANR from sorghum and switchgrass showed a high level of similarity. The catalytic mechanism, substrate-specificity and key residues of three reductases were deduced from crystal structures, site-directed mutagenesis, molecular docking, kinetics, and thermodynamic ana-lyses. Although DFR displayed its highest activity against dihydroflavonols, it also showed activity against flavanones and anthocyanidins. It was inhibited by the flavonol quercetin and high concentrations of dihydroflavonols/flavonones. SbFNR1 and SbFNR2 did not show any activity against dihydroflavonols. However, SbFNR1 displayed activity against flavanones and ANR activity against two anthocyanidins, cyanidin and pelargonidin. Therefore, SbFNR1 and SbFNR2 could be specific ANR isozymes without delphinidin activity. Sorghum has high concentrations of 3-deoxyanthocyanidins in vivo, supporting the observed high activity of SbDFR against flavonols. Mining of expression data indicated substantial induction of these three reductase genes in both switchgrass and sorghum in response to biotic stress. Key signature sequences for proper DFR/ANR classification are proposed and could form the basis for future metabolic engineering of flavonoid metabolism.

Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids.

APX is a key antioxidant enzyme in higher plants, scavenging H2O2 with ascorbate in several cellular compartments. Here, we report the crystal structures of cytosolic ascorbate peroxidase from switchgrass (Panicum virgatum L., Pvi), a strategic feedstock plant with several end uses. The overall structure of PviAPX was similar to the structures of other APX family members, with a bound ascorbate molecule at the ɣ-heme edge pocket as in other APXs. Our results indicated that the H2O2-dependent oxidation of ascorbate displayed positive cooperativity. Significantly, our study suggested that PviAPX can oxidize a broad range of phenylpropanoids with δ-meso site in a rather similar efficiency, which reflects its role in the fortification of cell walls in response to insect feeding. Based on detailed structural and kinetic analyses and molecular docking, as well as that of closely related APX enzymes, the critical residues in each substrate-binding site of PviAPX are proposed. Taken together, these observations shed new light on the function and catalysis of PviAPX, and potentially benefit efforts improve plant health and biomass quality in bioenergy and forage crops.

Effects of a Virtual Reality-Based Meditation Intervention on Anxiety and Depression Among Patients With Acute Leukemia During Induction Chemotherapy: A Randomized Controlled Trial.

BACKGROUND: Emerging evidence supports that virtual reality (VR)-based meditation interventions may improve anxiety and depression among patients with cancer. However, empirical studies involving patients with acute leukemia during induction chemotherapy are limited. OBJECTIVE: This study aimed to examine the effects of VR-based meditation intervention on alleviating anxiety and depression and improving the quality of life among patients with acute leukemia during induction chemotherapy. METHODS: This randomized controlled trial recruited 63 patients newly diagnosed with acute leukemia. Participants were randomly assigned to an intervention group (received VR-based meditation for 20 min daily for 14 days) and a control group. Anxiety, depression, and quality of life were measured using the State Anxiety Inventory, the Center for Epidemiological Studies Depression Scale, and the Functional Assessment of Cancer Therapy-Leukemia Questionnaire, respectively. All outcomes were measured at baseline and post-intervention. RESULTS: Compared with patients in the control group, those in the intervention group demonstrated a significantly greater reduction in anxiety (P = .04) and improvement in quality of life (P = .04). However, no significant difference was noted in depression levels between groups (P = .09), although a decreasing trend was observed in the intervention group. CONCLUSION: Virtual reality-based meditation intervention effectively alleviated anxiety and improved the quality of life among acute leukemia patients during induction chemotherapy. Future randomized controlled trials with larger sample sizes and longer follow-up periods are warranted. IMPLICATION FOR PRACTICE: Virtual reality-based meditation can be applied in clinical practice virtually anytime and anywhere to provide a convenient intervention for anxiety reduction for acute leukemia patients during induction chemotherapy.

A sorghum ascorbate peroxidase with four binding sites has activity against ascorbate and phenylpropanoids.

In planta, H2O2 is produced as a by-product of enzymatic reactions and during defense responses. Ascorbate peroxidase (APX) is a key enzyme involved in scavenging cytotoxic H2O2. Here, we report the crystal structure of cytosolic APX from sorghum (Sorghum bicolor) (Sobic.001G410200). While the overall structure of SbAPX was similar to that of other APXs, SbAPX uniquely displayed four bound ascorbates rather than one. In addition to the ɣ-heme pocket identified in other APXs, ascorbates were bound at the δ-meso and two solvent-exposed pockets. Consistent with the presence of multiple binding sites, our results indicated that the H2O2-dependent oxidation of ascorbate displayed positive cooperativity. Bound ascorbate at two surface sites established an intricate proton network with ascorbate at the ɣ-heme edge and δ-meso sites. Based on crystal structures, steady-state kinetics, and site-directed mutagenesis results, both ascorbate molecules at the ɣ-heme edge and the one at the surface are expected to participate in the oxidation reaction. We provide evidence that the H2O2-dependent oxidation of ascorbate by APX produces a C2-hydrated bicyclic hemiketal form of dehydroascorbic acid at the ɣ-heme edge, indicating two successive electron transfers from a single-bound ascorbate. In addition, the δ-meso site was shared with several organic compounds, including p-coumaric acid and other phenylpropanoids, for the potential radicalization reaction. Site-directed mutagenesis of the critical residue at the ɣ-heme edge (R172A) only partially reduced polymerization activity. Thus, APX removes stress-generated H2O2 with ascorbates, and also uses this same H2O2 to potentially fortify cell walls via oxidative polymerization of phenylpropanoids in response to stress.

Thyroid function, renal function, and depression: an association study.

Objective: To investigate the correlations between thyroid function, renal function, and depression. Methods: Clinical data of 67 patients with Major depressive disorder (MDD) and 36 healthy control subjects between 2018 and 2021 were collected to compare thyroid and renal function. Thyroid and renal functions of depressed patients were then correlated with the Hamilton Depression Rating Scale (HAMD) and the Hamilton Anxiety Rating Scale (HAMA).Spearman correlation analysis was used to find the correlation between renal function, thyroid function, and depression. A logistic regression was performed to find significant predictors of depression. Results: Triiodothyronine protamine (T3), thyroxine (T4), free triiodothyronine protamine (FT3), uric acid, sodium, and anion gap were lower in the MDD group than in the control group (p < 0.05). Correlation analysis of thyroid function, renal function, and factor terms of HAMD in the MDD group suggested that diurnal variation, hopelessness, and depression level were positively correlated with thyrotropin (TSH) (p < 0.05). Cognitive disturbance, retardation, and depression level were negatively correlated with creatinine (p < 0.05). Diurnal variation was negatively correlated with sodium ion (p < 0.01); hopelessness and depression level were positively correlated with chloride ion (p < 0.05); diurnal variation, retardation, and depression level were negatively correlated with anion gap (p < 0.05). Diurnal variation (p < 0.01) and retardation (p < 0.05) were negatively correlated with osmolality. Cognitive disturbance and depression level were positively correlated with estimated glomerular filtration rate (eGFR) (p < 0.05). In the MDD group, correlation analysis of thyroid function, renal function, and HAMA factor terms suggested that the total HAMA score and anxiety level were positively correlated with chloride ion (p < 0.05); psychic anxiety, total HAMA score, and anxiety level were negatively correlated with anion gap (p < 0.05). Furthermore, a low level of anion gap was an independent risk factor for depression and anxiety levels (p < 0.05). Conclusion: Low thyroid function and reduced waste metabolized by the kidneys in patients with MDD suggest a low intake and low metabolism in depressed patients. In addition, subtle fluctuations in the anion gap in depressed patients were strongly correlated with the degree of depression and anxiety.

X-ray Crystallography: Seeding Technique with Cytochrome P450 Reductase.

Cytochrome P450 reductase (CPR) is a multi-domain protein that acts as a redox partner of cytochrome P450s. The CPR contains a flavin adenine dinucleotide (FAD)-binding domain, a flavin mononucleotide (FMN)-binding domain, and a connecting domain. To achieve catalytic events, the FMN-binding domain needs to move relative to the FAD-binding domain, and this high flexibility complicates structural determination in high-resolution by X-ray crystallography. Here, we demonstrate a seeding technique of sorghum CPR crystals for resolution improvement, which can be applied to other poorly diffracting protein crystals. Protein expression is completed using an E. coli cell line with a high protein yield and purified using chromatography techniques. Crystals are screened using an automated 96-well plating robot. Poorly diffracting crystals are originally grown using a hanging drop method from successful trials observed in sitting drops. A macro seeding technique is applied by transferring crystal clusters to fresh conditions without nucleation to increase crystal size. Prior to diffraction, a dehydration technique is applied by serial transfer to higher precipitant concentrations. Thus, an increase in resolution by 7 Å is achieved by limiting the inopportune effects of the flexibility inherent to the domains of CPR, and secondary structures of SbCPR2c are observed. Graphical abstract.

Prevalence and factors associated with compassion satisfaction and compassion fatigue among Chinese oncology healthcare professionals: A cross-sectional survey.

Objective: This cross-sectional study examined the prevalence and factors associated with compassion satisfaction and fatigue among oncology healthcare professionals (doctors and nurses) in mainland China. Methods: A total of 337 subjects were recruited via convenience sampling from the oncology departments of five general hospitals in Guangzhou, Guangdong, China. They were invited to complete a survey that included demographic characteristics, the Profession Quality of life Scale, the Brief Cope Questionnaire, and the Connor-Davidson Resilience Scale. Results: The findings showed medium levels of compassion satisfaction, burnout, and secondary traumatic stress among oncology healthcare professionals in China, reaching rates of 78.34%, 63.50% and 75.96%, respectively. Multiple regression analyses suggested that active coping, positive reframing, and strength were the significant factors of compassion satisfaction, explaining 48.6% of the total variance (P â€‹< â€‹0.001). Substance use and self-blame were the significant factors of burnout, explaining 45.1% of the total variance (P â€‹< â€‹0.001). Venting, denial, substance use, self-blame, and strength were the significant factors of secondary traumatic stress, explaining 37.6% of the total variance (P â€‹< â€‹0.001). Conclusions: The high prevalence of compassion fatigue warrants the attention of the hospitals' senior management. The effective coping styles identified may be considered when developing strategies to improve the professional quality of life among oncology healthcare professionals.

Conformational Rearrangements in the Redox Cycling of NADPH-Cytochrome P450 Reductase from Sorghum bicolor Explored with FRET and Pressure-Perturbation Spectroscopy.

NADPH-cytochrome P450 reductase (CPR) from Sorghum bicolor (SbCPR) serves as an electron donor for cytochrome P450 essential for monolignol and lignin production in this biofuel crop. The CPR enzymes undergo an ample conformational transition between the closed and open states in their functioning. This transition is triggered by electron transfer between the FAD and FMN and provides access of the partner protein to the electron-donating FMN domain. To characterize the electron transfer mechanisms in the monolignol biosynthetic pathway better, we explore the conformational transitions in SbCPR with rapid scanning stop-flow and pressure-perturbation spectroscopy. We used FRET between a pair of donor and acceptor probes incorporated into the FAD and FMN domains of SbCPR, respectively, to characterize the equilibrium between the open and closed states and explore its modulation in connection with the redox state of the enzyme. We demonstrate that, although the closed conformation always predominates in the conformational landscape, the population of open state increases by order of magnitude upon the formation of the disemiquinone state. Our results are consistent with several open conformation sub-states differing in the volume change (ΔV0) of the opening transition. While the ΔV0 characteristic of the oxidized enzyme is as large as -88 mL/mol, the interaction of the enzyme with the nucleotide cofactor and the formation of the double-semiquinone state of CPR decrease this value to -34 and -18 mL/mol, respectively. This observation suggests that the interdomain electron transfer in CPR increases protein hydration, while promoting more open conformation. In addition to elucidating the functional choreography of plant CPRs, our study demonstrates the high exploratory potential of a combination of the pressure-perturbation approach with the FRET-based monitoring of protein conformational transitions.

Functional and structural insight into the flexibility of cytochrome P450 reductases from Sorghum bicolor and its implications for lignin composition.

Plant NADPH-dependent cytochrome P450 reductase (CPR) is a multidomain enzyme that donates electrons for hydroxylation reactions catalyzed by class II cytochrome P450 monooxygenases involved in the synthesis of many primary and secondary metabolites. These P450 enzymes include trans-cinnamate-4-hydroxylase, p-coumarate-3'-hydroxylase, and ferulate-5-hydroxylase involved in monolignol biosynthesis. Because of its role in monolignol biosynthesis, alterations in CPR activity could change the composition and overall output of lignin. Therefore, to understand the structure and function of three CPR subunits from sorghum, recombinant subunits SbCPR2a, SbCPR2b, and SbCPR2c were subjected to X-ray crystallography and kinetic assays. Steady-state kinetic analyses demonstrated that all three CPR subunits supported the oxidation reactions catalyzed by SbC4H1 (CYP73A33) and SbC3'H (CYP98A1). Furthermore, comparing the SbCPR2b structure with the well-investigated CPRs from mammals enabled us to identify critical residues of functional importance and suggested that the plant flavin mononucleotide-binding domain might be more flexible than mammalian homologs. In addition, the elucidated structure of SbCPR2b included the first observation of NADP+ in a native CPR. Overall, we conclude that the connecting domain of SbCPR2, especially its hinge region, could serve as a target to alter biomass composition in bioenergy and forage sorghums through protein engineering.

Structural studies of Myceliophthora Thermophila Laccase in the presence of deep eutectic solvents.

In this work, we elucidated the interactions between Myceliophthora thermophila laccase and deep eutectic solvent (DES) by crystallographic and kinetics analyses. Four types of DESs with different hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), including lactic acid: betaine, glycerol: choline chloride, lactic acid: choline chloride and glycerol: betaine was used. The results revealed that different DES have different effects on laccase activity. Lactic acid-betaine (2:1) DES has shown to enhance laccase activity up to 300 % at a concentration ranged from 2% to 8% v/v, while glycerol: choline chloride and lactic acid: choline chloride DES choline chloride-based DES have found to possess inhibitory effects on laccase under the same concentration range. Detailed kinetic study showed that glycerol: choline chloride DES is a S-parabolic-I-parabolic mixed non-competitive inhibitor, where conformational changes can occur. The crystal structures of laccase with lactic acid: choline chloride DES (LCDES) were obtained at 1.6 Å. Crystallographic analysis suggested that the addition of LCDES causes changes in the laccase active site, but the increase in water molecules observed in the resulting crystal prevented laccase from experiencing drastic structural change. Fluorescence and circular dichroism spectroscopies were also applied to determine the effects of DES on the structural conformation of laccase. The results have confirmed that the presence of DES can trigger changes in the local environments of the amino acids in the active site of laccase which contributes to the changes in its activity and stability.

The value of color Doppler ultrasound in the diagnosis of thyroid nodules: a systematic review and meta-analysis.

BACKGROUND: This study aimed to analyze the value of color Doppler ultrasound in the diagnosis of thyroid nodules. METHODS: We searched the PubMed, Web of Science, Embase, and Cochrane Library databases for randomized controlled trials (RCTs) on using color Doppler ultrasound, thyroid nodules, thyroid tumors, and Doppler ultrasound to diagnose the thyroid nodules. The outcome indicators in the articles had to include the numbers of true positives (TP), false positives (FP), false negatives (FN), and true negatives (TN). Subsequently, the Jadad tool was adopted to evaluate the quality of the included articles, and Review Manager 5.3 software was used to conduct a meta-analysis of the experimental data. RESULTS: A total of eight suitable articles were selected. The results showed that the estimated sensitivity and specificity of color Doppler ultrasound for the diagnostic of thyroid nodules were 0.46-0.89 and 0.00-1.00, respectively. The pooled estimate of sensitivity for the different articles was 0.71 [95% confidence interval (CI): 0.46-0.89], and the pooled estimate of specificity was 0.77 (95% CI: 0.00-1.00). The area under the summary receiver operating characteristic (SROC) curve (AUC) was 0.917, which was larger than 0.9, signifying high diagnostic accuracy. This suggests that color doppler ultrasound can realize the clinical diagnosis of thyroid nodules. DISCUSSION: In summary, the results of this study could provide a clinical data for the promotion and application of color Doppler ultrasound in the clinical diagnosis of thyroid nodules, as well as further reliable data for follow-up clinical research on the diagnosis and treatment of thyroid nodules.

Site-Specific Synthesis of Cysteine-Bridged Glycoproteins via Expressed Protein Glycoligation.

Site-specific glycosylation of a functional recombinant protein thioester is reported. The thioester functionalized protein sfGFP-Y151ThioD, prepared by genetic code expansion, underwent native chemical ligation with the cysteine-conjugated glycans H-Cys-NH-GlcNAc and H-Cys-NH-(GlcNAc)2(Man)3 to give the corresponding cysteine-bridged glycoproteins. The intact glycoproteins, which retained their fluorescence, were characterized by top-down mass spectrometry and gel electrophoresis. The bridging cysteine provided a convenient handle for affinity chromatography purification of the glycoproteins via a removable biotin tag. Given the influence that specific glycoforms can have on a protein's function, the ability to attach a homogeneous glycan to an intact protein in a functional group controlled yet sequon-independent manner could find widespread application. These preliminary results set the stage for development of the expressed protein glycoligation (EPG) concept.

Structure and Function of the Cytochrome P450 Monooxygenase Cinnamate 4-hydroxylase from Sorghum bicolor.

Cinnamate 4-hydroxylase (C4H; CYP73A) is a cytochrome P450 monooxygenase associated externally with the endoplasmic reticulum of plant cells. The enzyme uses NADPH-cytochrome P450 reductase as a donor of electrons and hydroxylates cinnamic acid to form 4-coumaric acid in phenylpropanoid metabolism. In order to better understand the structure and function of this unique class of plant P450 enzymes, we have characterized the enzyme C4H1 from lignifying tissues of sorghum (Sorghum bicolor), encoded by Sobic.002G126600 Here we report the 1.7 Å resolution crystal structure of CYP73A33. The obtained structural information, along with the results of the steady-state kinetic analysis and the absorption spectroscopy titration, displays a high degree of similarity of the structural and functional features of C4H to those of other P450 proteins. Our data also suggest the presence of a putative allosteric substrate-binding site in a hydrophobic pocket on the enzyme surface. In addition, comparing the newly resolved structure with those of well-investigated cytochromes P450 from mammals and bacteria enabled us to identify those residues of critical functional importance and revealed a unique sequence signature that is potentially responsible for substrate specificity and catalytic selectivity of C4H.

The PKCδ-Nrf2-ARE signalling pathway may be involved in oxidative stress in arsenic-induced liver damage in rats.

Arsenic poisoning is a worldwide endemic disease that affects thousands of people. Growing evidence from animal, cell, and human studies indicates that arsenic has deleterious effects on the liver. Oxidative stress is considered the primary mechanism for arsenic toxicity in liver damage. However, the mechanisms remain unclear. In light of this fact, the main objective of this study was to investigate the effects of the protein kinase C delta-nuclear factor E2-related factor 2-antioxidant response element (PKCδ-Nrf2-ARE) signalling pathway on oxidative stress in liver damage. In the present study, we used a model of liver damage induced by coal-burning arsenic in rats, which was set up by our research group. The oxidative stress index and the transcription and protein expression levels of PKCδ, Nrf2, Keap1, SOD1, and GPx1 were detected, and then their correlation analyses were carried out. The results demonstrated that coal-burning arsenic can cause oxidative stress liver damage in rats, which may be related to the PKCδ-Nrf2-ARE signalling pathway. This study may provide a new pathway for studies of the mechanisms of arsenism.

[Relationship between changes of genetic damage and development of disease in patients with arsenism caused by coal-burning].

OBJECTIVE: To investigate the changes of genetic damage in patients with arsenism caused by coal-burning in 9 years. To analyze the relationship between the changes of genetic damage and disease progression and provide a basis for condition monitoring. METHODS: Of 206 arsenism patients from the area with endemic arsenism in Guizhou province were tracking surveyed in February 1998 and divided into 4 groups, including suspicious, mild, moderate and severe poisoning group. Another 67 healthy residents from a neighbour township 12 km away where arsenic was not prevalent were surveyed. Over a 9-year follow-up, 131 arsenism patients and 45 controls with the complete biochemical indexes among them were selected as subjects in December 2006. Arsenic (As) concentration of urine and hair were detected by silver diethyldithiocarbamate spectrophotometry (Ag-DDC). Micronucleis (MN) and chromosome aberrations (CA) were analyzed by conventional methods. DNA single-strand breaks of peripheral blood were measured by single cell gel electrophoresis (SCGE), and the tail lengths of comet were used to measure DNA damage. RESULTS: Among the control, suspicious, mild, moderate and severe arsenic poisoning group, the As contents of urine and hair were respectively (34.16 ± 10.25), (52.35 ± 22.41), (62.26 ± 31.13), (71.43 ± 49.92), (78.45 ± 50.64) µg/L and (1.37 ± 0.56), (3.69 ± 1.78), (4.88 ± 3.49), (5.21 ± 3.10), (6.25 ± 4.04) µg/g in 2006, which were lower than that 9 years before (urine as contents were (36.07 ± 20.70), (73.65 ± 41.33) , (90.92 ± 82.14) , (126.55 ± 107.31) and (139.44 ± 90.90) µg/L, and hair As contents were (1.41 ± 1.18), (4.85 ± 4.20), (5.72 ± 4.07) , (6.43 ± 4.32) and (7.19 ± 4.68) µg/g, respectively, F value was 10.63, 7.72, 14.66, 11.00 respectively, all P values were < 0.05). Except for suspicious poisoning group, the differences of urine As contents in the other groups all showed significance (P < 0.05). The incidences of MN were (0.238 ± 0.130) %, (0.268 ± 0.192) %, (0.283 ± 0.157) % and (0.391 ± 0.233)%; the incidences of CA were (14.36 ± 5.44) %, (18.09 ± 6.49) %, (19.38 ± 5.63)% and (19.83 ± 5.84) %; the tail lengths of comet were (29.88 ± 13.81) , (29.84 ± 12.80) , (34.50 ± 9.88) and (41.58 ± 12.98) µm respectively in 2006 for all poisoning groups; which were higher than that 9 years before(the incidences of MN were (0.163 ± 0.051) %, (0.186 ± 0.117) %, (0.196 ± 0.104) % and (0.273 ± 0.142) %; the incidences of CA were (13.18 ± 5.17)%, (14.48 ± 6.61)%, (15.67 ± 8.49) % and (16.90 ± 8.38) %; the tail lengths of comet were (15.07 ± 12.93) , (19.57 ± 8.80) , (27.03 ± 10.77) and (34.71 ± 14.95) µm) , except for the incidences of MN and CA in suspicious poisoning group and of MN in mild poisoning group , the differences of the three indexes in the other groups were significant (P < 0.05) . The state of illness of arsenic poisoning patients aggravated 9 years later. With the increase of urine and hair As contents and the development of arsenism, the incidences of MN, CA and the tail lengths of comet of all poisoning groups increased. There were positive correlations among them (r values were respectively 0.212, 0.316, 0.232, 0.263, 0.321, 0.654 and 0.760) (P < 0.05). CONCLUSION: The exacerbation of genetic damage was related to constantly high arsenic loads. The accumulation of genetic damage and its irreversibility might be one of the important reasons of the development of arsenism and cancer.