MANF Promotes Unexplained Recurrent Miscarriages by Interacting with NPM1 and Downregulating Trophoblast Cell Migration and Invasion.

Dysplasia and invasive defects in early trophoblasts contribute to unexplained recurrent miscarriages (URMs). Mesencephalic astrocyte-derived neurotrophic factor (MANF) inhibits migration and invasion in some cancer cells, but its role in pregnancy-related diseases remains unresolved. Here, we found that MANF levels in the peripheral blood and aborted tissue of URM women were higher than in normal controls, irrespective of pregnancy or miscarriage. We confirm the interaction between MANF and nucleophosmin 1 (NPM1) in trophoblasts of URM patients, which increases the ubiquitination degradation of NPM1, leading to upregulation of the p53 signaling pathway and inhibition of cell proliferation, migration, and invasion ability. Using a URM mouse model, we found that MANF downregulation resulted in reduced fetal resorption; however, concomitant NPM1 downregulation led to increased abortion rates. These data indicate that MANF triggers miscarriage via NPM1 downregulation and p53 activation. Thus, MANF downregulation or disruption of the MANF-NPM1 interaction could be targets for URM therapeutics.

An evaluation of the clinical efficacy of the application of 28mm cryoballoon for linear ablation of left atrial apex combined with enlarged pulmonary vein vestibule ablation for persistent atrial fibrillation.

OBJECTIVE: to retrospectively investigate the efficacy and safety of the application of 28 mm cryoballoon for pulmonary vein electrical isolation (PVI) combined with top left atrial linear ablation and pulmonary vein vestibular expansion ablation for persistent atrial fibrillation. METHODS: From July 2016 to December 2020, 413 patients diagnosed with persistent atrial fibrillation were evaluated, including 230 (55.7%) in the PVI group (PVI only) and 183 (44.3%) in the PVIPLUS group (PVI plus ablation of the left atrial apex and pulmonary vein vestibule). The safety and efficacy of the two groups were retrospectively analyzed. RESULTS: The AF/AT/AFL-free survival rates at 6, 12, 18, 24 and 30 months after procedure was 86.6%, 72.6%, 70.0%, 61.1% and 56.3% in the PVI group and 94.5%, 87.0%, 84.1%, 75.0% and 67.9% in the PVIPLUS group, respectively. At 30 months after procedure, the AF/AT/AFL-free survival rate was significantly higher in the PVIPLUS group than in the PVI group (P = 0.036; HR:0.63; 95% CI:0.42 to 0.95). CONCLUSION: The application of 28-mm cryoballoon for pulmonary vein electrical isolation combined with linear ablation of the left atrial apex and expanded ablation of the pulmonary vein vestibule improves the outcome of persistent atrial fibrillation.

Dissecting the Enantioselective Neurotoxicity of Isocarbophos: Chiral Insight from Cellular, Molecular, and Computational Investigations.

Chiral organophosphorus pollutants are found abundantly in the environment, but the neurotoxicity risks of these asymmetric chemicals to human health have not been fully assessed. Using cellular, molecular, and computational toxicology methods, this story is to explore the static and dynamic toxic actions and its stereoselective differences of chiral isocarbophos toward SH-SY5Y nerve cells mediated by acetylcholinesterase (AChE) and further dissect the microscopic basis of enantioselective neurotoxicity. Cell-based assays indicate that chiral isocarbophos exhibits strong enantioselectivity in the inhibition of the survival rates of SH-SY5Y cells and the intracellular AChE activity, and the cytotoxicity of (S)-isocarbophos is significantly greater than that of (R)-isocarbophos. The inhibitory effects of isocarbophos enantiomers on the intracellular AChE activity are dose-dependent, and the half-maximal inhibitory concentrations (IC50) of (R)-/(S)-isocarbophos are 6.179/1.753 µM, respectively. Molecular experiments explain the results of cellular assays, namely, the stereoselective toxic actions of isocarbophos enantiomers on SH-SY5Y cells are stemmed from the differences in bioaffinities between isocarbophos enantiomers and neuronal AChE. In the meantime, the modes of neurotoxic actions display that the key amino acid residues formed strong noncovalent interactions are obviously different, which are related closely to the molecular structural rigidity of chiral isocarbophos and the conformational dynamics and flexibility of the substrate binding domain in neuronal AChE. Still, we observed that the stable "sandwich-type π-π stacking" fashioned between isocarbophos enantiomers and aromatic Trp-86 and Tyr-337 residues is crucial, which notably reduces the van der Waals' contribution (ΔGvdW) in the AChE-(S)-isocarbophos complexes and induces the disparities in free energies during the enantioselective neurotoxic conjugations and thus elucidating that (S)-isocarbophos mediated by synaptic AChE has a strong toxic effect on SH-SY5Y neuronal cells. Clearly, this effort can provide experimental insights for evaluating the neurotoxicity risks of human exposure to chiral organophosphates from macroscopic to microscopic levels.

MANF ameliorates DSS-induced mouse colitis via restricting Ly6ChiCX3CR1int macrophage transformation and suppressing CHOP-BATF2 signaling pathway.

Mesencephalic astrocyte-derived neurotrophic factor (MANF), an endoplasmic reticulum stress-inducible secreting protein, has evolutionarily conserved immune-regulatory function that contributes to the negative regulation of inflammation in macrophages. In this study, we investigated the profiles of MANF in the macrophages of the patients with active inflammatory bowel disease (IBD) and the mice with experimental colitis, which was induced in both myeloid cell-specific MANF knockout mice and wild-type mice by 3% dextran sodium sulfate (DSS) for 7 days. We found that MANF expression was significantly increased in intestinal macrophages from both the mice with experimental colitis and patients with active IBD. DSS-induced colitis was exacerbated in myeloid cell-specific MANF knockout mice. Injection of recombinant human MANF (rhMANF, 10 mg·kg-1·d-1, i.v.) from D4 to D6 significantly ameliorated experimental colitis in DSS-treated mice. More importantly, MANF deficiency in myeloid cells resulted in a dramatic increase in the number of Ly6ChiCX3CRint proinflammatory macrophages in colon lamina propria of DSS-treated mice, and the proinflammatory cytokines and chemokines were upregulated as well. Meanwhile, we demonstrated that MANF attenuated Th17-mediated immunopathology by inhibiting BATF2-mediated innate immune response and downregulating CXCL9, CXCL10, CXCL11 and IL-12p40; MANF functioned as a negative regulator in inflammatory macrophages via inhibiting CHOP-BATF2 signaling pathway, thereby protecting against DSS-induced mouse colitis. These results suggest that MANF ameliorates colon injury by negatively regulating inflammatory macrophage transformation, which shed light on a potential therapeutic target for IBD.

Rhizoctonia solani transcriptional activator interacts with rice WRKY53 and grassy tiller 1 to activate SWEET transporters for nutrition.

INTRODUCTION: Rhizoctonia solani, the causative agent of the sheath blight disease (ShB), invades rice to obtain nutrients, especially sugars; however, the molecular mechanism via which R. solani hijacks sugars from rice remains unclear. OBJECTIVES: In this study, rice-R. solani interaction model was used to explore whether pathogen effector proteins affect plant sugar absorption during infection. METHODS: Yeast one-hybrid assay was used to identify Activator of SWEET2a (AOS2) from R. solani. Localization and invertase secretion assays showed that nuclear localization and secreted function of AOS2. Hexose transport assays verified the hexose transporter activity of SWEET2a and SWEET3a. Yeast two-hybrid assays, Bimolecular fluorescence complementation (BiFC) and transactivation assay were conducted to verify the AOS2-WRKY53-Grassy tiller 1 (GT1) transcriptional complex and its activation of SWEET2a and SWEET3a. Genetic analysis is used to detect the response of GT1, WRKY53, SWEET2a, and SWEET3a to ShB infestation. Also, the soluble sugar contents were measured in the mutants and overexpression plants before and after the inoculation of R. solani. RESULTS: The present study found that R. solani protein AOS2 activates rice SWEET2a and localized in the nucleus of tobacco cells and secreted in yeast. AOS2 interacts with rice transcription factor WRKY53 and GT1 to form a complex that activates the hexose transporter gene SWEET2a and SWEET3a and negatively regulate rice resistance to ShB. CONCLUSION: These data collectively suggest that AOS2 secreted by R. solani interacts with rice WRKY53 and GT1 to form a transcriptional complex that activates SWEETs to efflux sugars to apoplast; R. solani acquires more sugars and subsequently accelerates host invasion.

Invasion and Propagation of White Spot Syndrome Virus: Hijacking of the Cytoskeleton, Intracellular Transport Machinery, and Nuclear Import Transporters.

The pathogenesis of white spot syndrome virus (WSSV) is largely unclear. In this study, we found that actin nucleation and clathrin-mediated endocytosis were recruited for internalization of WSSV into crayfish hematopoietic tissue (Hpt) cells. This internalization was followed by intracellular transport of the invading virions via endocytic vesicles and endosomes. After envelope fusion within endosomes, the penetrated nucleocapsids were transported along microtubules toward the periphery of the nuclear pores. Furthermore, the nuclear transporter CqImportin α1/ß1, via binding of ARM repeat domain within CqImportin α1 to the nuclear localization sequences (NLSs) of viral cargoes and binding of CqImportin ß1 to the nucleoporins CqNup35/62 with the action of CqRan for docking to nuclear pores, was hijacked for both targeting of the incoming nucleocapsids toward the nuclear pores and import of the expressed viral structural proteins containing NLS into the cell nucleus. Intriguingly, dysfunction of CqImportin α1/ß1 resulted in significant accumulation of incoming nucleocapsids on the periphery of the Hpt cell nucleus, leading to substantially decreased introduction of the viral genome into the nucleus and remarkably reduced nuclear import of expressed viral structural proteins with NLS; both of these effects were accompanied by significantly inhibited viral propagation. Accordingly, the survival rate of crayfish post-WSSV challenge was significantly increased after dysfunction of CqImportin α1/ß1, also showing significantly reduced viral propagation, and was induced either by gene silencing or by pharmacological blockade via dietary administration of ivermectin per os. Collectively, our findings improve our understanding of WSSV pathogenesis and support future antiviral designing against WSSV. IMPORTANCE As one of the largest animal DNA viruses, white spot syndrome virus (WSSV) has been causing severe economical loss in aquaculture due to the limited knowledge on WSSV pathogenesis for an antiviral strategy. We demonstrate that the actin cytoskeleton, endocytic vesicles, endosomes, and microtubules are hijacked for WSSV invasion; importantly, the nuclear transporter CqImportin α1/ß1 together with CqRan were recruited, via binding of CqImportin ß1 to the nucleoporins CqNup35/62, for both the nuclear pore targeting of the incoming nucleocapsids and the nuclear import of expressed viral structural proteins containing the nuclear localization sequences (NLSs). This is the first report that NLSs from both viral structure proteins and host factor are elaborately recruited together to facilitate WSSV infection. Our findings provide a novel explanation for WSSV pathogenesis involving systemic hijacking of host factors, which can be used for antiviral targeting against WSSV disease, such as the blockade of CqImportin α1/ß1 with ivermectin.

Cold Plasma Irradiation Regulates Inflammation and Oxidative Stress in Human Bronchial Epithelial Cells and Human Non-Small Cell Lung Carcinoma.

Atmospheric pressure cold plasma has shown multiple biological effects of anti-bacteria and anti-cancer. In this study, the effect of atmospheric pressure cold plasma on respiratory inflammation and oxidant stress is explored. Tunicamycin was used to stimulate human bronchial epithelial cells (HBECs) and A549 cells for inflammatory response and oxidative stress, followed by atmospheric pressure cold plasma treatment. For HBECs and A549 cells, atmospheric pressure cold plasma was able to alleviate tunicamycin-induced cell proliferation inhibition, inflammation and oxidant stress, and enhance nuclear factor-erythroid-2-related factor 2 (NRF2) pathway activation. Moreover, NRF2/ARE (anti-oxidant response elements) pathway was involved in the regulation of atmospheric pressure cold plasma on tunicamycin-induced oxidative stress. These results suggest the positive effect of atmospheric pressure cold plasma on inflammation and oxidant stress of respiratory system, indicating the therapeutic potential of atmospheric pressure cold plasma for respiratory diseases.

Atmospheric ozonolysis of crotonaldehyde in the absence and presence of hydroxylated silica oligomer cluster adsorption.

As one of the main components of combustion of tobacco products occurs (CARB), crotonaldehyde has an acute toxicity and widely exists in the atmosphere, which is harmful to human health. The removal efficiency of VOCs by ozonation can reach 80-90%. Based on the theory of quantum chemistry, the degradation mechanism, kinetics and toxicity of crotonaldehyde by ozonation in gas phase and heterogeneous phase were studied. Ozone was added to the olefins unsaturated double bond to form a five-membered ring primary ozonide, which was further fractured due to its unstable structure to form a Criegee intermediate and an aldehyde compound. The reaction rate constant of crotonaldehyde with ozone was 1.24 × 10-17 cm3 molecule-1 s-1 at 298 K and 1 atm, which was an order of magnitude higher than the experimental value. From toxicity assessment, it was found that the ozonation of crotonaldehyde is beneficial to the removal of toxicity. Mineral dust aerosol exists in the atmosphere in large quantities, and SiO2 is the most abundant component. VOCs are transformed into particle state on their surface through homogeneous nucleation and heterogeneous nucleation. Referring to the crystal structure of SiO2, five hydroxylated silica oligomer cluster structures were simulated and the adsorption configurations of crotonaldehyde on their surface were simulated. The adsorption of crotonaldehyde on the surface of the clusters was achieved by forming hydrogen bonds and had good adsorption effects. The adsorption of hydroxylated silica oligomer clusters didn't change the ozonation mechanism of crotonldehyde, but had a certain effect on the reaction rate.

The roles of HO•, ClO• and BrO• radicals in caffeine degradation: A theoretical study.

ClO• and BrO• are newly discovered reactive radicals that contribute to the degradation of micropollutants. However, the research on pollutant degradation by ClO• and BrO• is still lacking. Thus, the mechanism, kinetics, and toxicity of caffeine degradation by HO•, ClO•, and BrO• were computationally studied and compared. Results showed that radical adduct formation (RAF) reaction was dominant for HO•, ClO•, and BrO• initiated reactions of caffeine. The main reaction sites were C5 and C8 of caffeine for HO•, while only the RAF reaction on C8 was prominent for ClO• and BrO•. The initiated reaction rate constants of caffeine by HO•, ClO•, and BrO• were in the order of HO• (5.29 × 109 M-1 s-1) > ClO• (1.40 × 109 M-1 s-1) > BrO• (2.17 × 108 M-1 s-1). The kinetic simulation verified that ClO• played a crucial role in the degradation of caffeine by the UV/chlorine process. In addition to HO-adducts, the subsequent reaction mechanisms of ClO- and BrO-adducts have also been investigated. The formation mechanisms of several important products, namely dimethylparabanic acid (P2), di(N-hydroxymethyl) parabanic acid (P5), 1,3,7-trimethyluric acid (P6), and 8-oxocaffeine (P11), were elucidated. Remarkably, stable chlorinated and brominated intermediates or products were not generated in ClO•- and BrO•-mediated subsequent degradations of caffeine. The assessment of aquatic toxicity and health effects showed that caffeine could penetrate the blood-brain barrier (human), and caffeine and its degradation products were potentially harmful to the aquatic environment.

Mono-macrophage-Derived MANF Protects Against Lipopolysaccharide-Induced Acute Kidney Injury via Inhibiting Inflammation and Renal M1 Macrophages.

The outburst of renal inflammatory response has been found to be a crucial cause of acute kidney injury (AKI). Attenuating the renal inflammation is an effective way for AKI treatment. Mesencephalic astrocyte-derived neurotrophic factor (MANF) has been proven to be an anti-inflammatory factor. However, the effect of MANF on renal inflammation induced by AKI is unknown. In this study, we have investigated the effect of mono-macrophage-derived MANF on AKI. We constructed the mono-macrophage-specific MANF knockout (Mø MANF-/-) mouse and used lipopolysaccharide (LPS) to induce AKI in wild-type (WT) and Mø MANF-/- mice. With mono-macrophage-specific MANF deficiency, Mø MANF-/- mice had a lower survival rate, more severe renal injury, and higher serum level of pro-inflammatory TNF-α after AKI was induced by LPS. Also, compared with WT mice, there were more M1 macrophages in renal tissues of Mø MANF-/- mice with LPS treatment, which might be attributed to the enhanced NF-κB activation in the renal microenvironment. Our study indicates the immunoregulatory role of mono-macrophage-derived MANF in the pathophysiological process of AKI, as well as the potential clinical application of MANF for AKI treatment.

Reactivity of aromatic contaminants towards nitrate radical in tropospheric gas and aqueous phase.

Aromatic compounds (ACs) give a substantial contribution to the anthropogenic emissions of volatile organic compounds. Nitrate radicals (NO3) are significant oxidants in the lower troposphere during nighttime, with concentrations of (2-20) × 108 molecules cm-3. In this study, the tropospheric gas and liquid phase reactions of ACs with nitrate radical are investigated using theoretical computational methods, which can give a deep insight into the reaction mechanisms and kinetics. Results show that the reactivity of ACs with nitrate radicals decreases as the electron donating characteristics of the functional group on the ACs decrease, as ΔG≠ of the reaction with NO3 increasing from -1.17 to 17.84 kcal mol-1. The reaction of NO3 towards ACs in the aqueous phase is more preferable, with the atmospheric lifetime 0.07-1281 min. An assessment of the aquatic toxicity of ACs and their degradation products indicated that the risk of their degradation products remains and should be given more attention.

Degradation of prosulfocarb by hydroxyl radicals in gas and aqueous phase: Mechanisms, kinetics and toxicity.

Prosulfocarb (PSC) is a thiocarbamate herbicide mainly used in winter cereals and a relevant aerosol precursor under OH radicals (OH) photooxidation conditions. We investigated the environmental risks, mechanisms, kinetics and products for the PSC withOH by employing theoretical chemical calculations. Two reaction types of H-abstraction andOH-addition reactions were taken into account. Whether in the atmosphere or aqueous particles, the most favorable pathway was the H-abstraction in the N-alkyl groups close to nitrogen atom. Subsequent reactions of primary intermediates were considered at different conditions. The total rate constants were determined as 2.62 × 10-10 cm3 molecule-1 s-1 and 4.96 × 10-11 cm3 molecule-1 s-1 at 298 K in atmosphere and aqueous particles, respectively. In natural water with theOH concentration of 10-15-10-18 mol l-1, the half-lives (t1/2) of PSC in theOH-initiated reactions were calculated as t1/2 = 2.40 × 104-2.40 × 107 s. With regard to the influence on human health and the ecosystem, oxidized products of PSC were estimated to be mutagenicity negative and had no obvious bioaccumulation potential. The aquatic toxicity of PSC and its degradation products was evaluated and the assessment results showed that the degradation of PSC was a toxicity-reduced process but they were still at toxic and harmful levels.

Mechanisms and Kinetic Parameters for the Gas-Phase Reactions of 3-Methyl-3-buten-2-one and 3-Methyl-3-penten-2-one with Ozone.

Ozonolysis of unsaturated ketones is a common atmospheric chemical process that plays a significant role in controlling the atmospheric budget of OH and O3, organic acids, and secondary organic aerosols (SOA). In this work, the detailed reaction mechanism and rate coefficients for the reactions of O3 with two unsaturated ketones, 3-methyl-3-buten-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332), were investigated by using density functional theory (DFT) and Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The results indicate that the major products are butanedione and formaldehyde for MBO332, and butanedione and acetaldehyde for MPO332. Possible reaction mechanism and thermodynamic parameters of some complex stable Criegee intermediates (SCIs) RR'COO were also be investigated in this study. Some organic peroxides can be regarded as the main products for the further reactions of SCIs. The rate constants calculated with O3 are 2.59 × 10-16 cm3 molecule-1 s-1 and 2.28 × 10-16 cm3 molecule-1 s-1 for MBO332 and MPO332 at 298 K and 1 atm. The total rate constant is negatively correlated with temperature (200-400 K) and positively correlated with pressure. The atmospheric half-lives of MBO332 and MPO332 based on O3 are estimated.

Theoretical study on gas-phase reactions of nitrate radicals with methoxyphenols: Mechanism, kinetic and toxicity assessment.

Creosol and 4-ethylguaiacol are two important methoxyphenols, lignin pyrolysis products, which are discharge into the atmosphere in large quantities. In this work, theoretical calculations of the reaction mechanism towards the two compounds with NO3 radicals was performed using DFT method. The rate constants and toxicity assessment were also investigated. The atmospheric lifetime for creosol and 4-ethylguaiacol were 0.82 and 0.19 h, respectively. A new reaction pathway was proposed for the transformation of methoxyl into hydroxyl, which has not yet been clarified in previous studies. The toxicity of methoxyphenols and their degradation products is closely related to their hydrophobicity. Although most degradation products are less toxic, they also should be pay more attention, especially for nitro-substituents. A new reaction pathway was proposed for the transformation of methoxyl into hydroxyl. The toxicity is closely related to their hydrophobicity.

[Notch1 Gene Silenced by RNAi Inhibits Oncogenicity of Myeloma Cell Line].

OBJECTIVE: To investigate the effect of Notch1 gene silencing by RNA interference on oncogenicity of multiple myeloma cells in NOD/SCID mice. METHODS: Targeting-silenced Notch1 gene was target-sotenced by transfection of Notch1-shRNA in multiple myeloma RPMI8226 cells of NOD/SCID mouse myeloma models, and the change of the volume and speed of oncogenicity in myeloma mouse models were evaluated after Notch1 gene silencing, and ELISA was used to detect the serum expression level of IL-6 and VEGF in the tumor-bearing mice. RESULTS: After Notch1 gene was silenced by Notch1-shRNA, the speed of tumor formation was significantly inhibited and the tumor volume was reduced in the tumor-bearing mice, as compared with the control group, and the difference was statistically significant (P<0.05). The serum level of IL-6 and VEGF in the tumor-bearing mice significantly decreased in comparison with the control group (P<0.05 ). CONCLUSION: The oncogenicity of myeloma cells in the models NOD/SCID mouse myeloma is significantly inhibited by Notch1 gene-silencing, and its mechanism may relate with the decreased secretory level of IL-6 and VEGF after Notch1 gene silencing. Notch1 gene silencing can be used as a new strategy to treat multiple myeloma.

[Targeting Notch1 Gene Inhibits the Proliferation of Multiple Myeloma Cells].

OBJECTIVE: To investigate the effects of Notch1 gene silencing on the proliferation and apoptosis of multiple myeloma cells, and to find the new targets for the treatment of multiple myeloma. METHODS: Notch1-shRNA targeted silencing Notch1 gene was transfected into multiple myeloma RPMI8226 cells, the CCK-8 and flow cytometry were used to detect the proliferation and apoptosis of myeloma cells after Notch1-shRNA transfection, the real-time fluorescence quantitative PCR was used to analyze expression level of Notch1 mRNA, and the Western blot were used to detect the expression level of Notch1 signaling pathway-related protein, such as Hes-1, Jagged-1, Jagged-2, BCL-2, PTEN, AKT and P-AKT. RESULTS: The mRNA and protein expression levels of Notch1-shRNA transfected cells were significantly inhibited in the experimental group assayed by real time fluorescence quantitative PCR and Western blot, the mRNA and protein expression level were down-regulated to 66% + 0.1%, 88% + 3.4% respectively, as compared with the control group(P<0.05). CCK-8 results confirmed that the cell proliferation rate was significantly decreased in the experimental group 48 hours after transfection. Flow cytometry results showed that the cell apoptosis rate was significantly higher in the experimental group than that in the control group. The expression levels of downstream protein Hes1, p-AKT and BCL-2 were decreased, the level of PTEN increased significantly after Notch1 gene silencing. CONCLUSION: Notch1 gene silencing by transfection of Notch1-shRNA can inhibit the proliferation of myeloma cells and induce their apoptosis, and its mechanism is related to the activation of PTEN gene and p-AKT signaling. Notch1 signal can be used as a potential target for multiple myeloma therapy.

[Effects of exogenous NO on ascorbate-glutathione cycle in loquat leaves under low temperature stress].

Three-year-old 'Zaozhong No. 6' loquat (Eriobotrya japonica Lindl.) seedlings were foliar-sprayed with 0.2, 0.5, 1.0 and 1.5 mmol x L(-1) of sodium nitroprusside (SNP), subjected to low temperature (-3 degrees) stress for 6 hours, and then cultured at 25 degrees C for four days. The antioxidant metabolites and enzymes in the seedling leaves were determined 0, 1, and 4 days after recovery. Comparing with the control (water spraying), all SNP treatments had a decreased H2O2 content but an increased content of glutathione (GSH) and ascorbic acid (AsA) and increased activity of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDAR) in the seedling leaves. Four days after recovery, the H2O2 content in the seedling leaves treated with 0.5 mmol x L(-1) of SNP decreased by 75.53%, while the GSH and AsA contents and the APX, GR, DHAR and MDAR activities were increased by 29.12%, 23.40%, 50.0%, 44.4%, 49.53%, and 62.68%, respectively. All of these suggested that appropriate dosage of exogenous NO could enhance the activity of antioxidant system in loquat leaves and alleviated the cell injury of loquat leaves under low temperature stress. In this study, the appropriate dosage of NO was 0.5 mmol x L(-1) of SNP.

[Effect of two different doses of letrozole in promoting ovulation in infertile women with polycystic ovarian syndrome].

OBJECTIVE: To investigate the effect of two different doses of letrozole in promoting ovulation in infertile women with polycystic ovarian syndrome (PCOS). METHODS: Seventy-six PCOS infertile women undergoing intrauterine insemination (IUI) or with anovulation were divided into two groups and received oral letrozole at the daily dose of 2.5 (n=36) or 5.0 mg (n=40) from the 3rd to the 7th day of the menstrual cycle. Three days after discontinuation of the medication (the 10th day of the menstrual cycle ), ultrasound scanning was performed to monitor the follicle development. When the diameter of the biggest follicle reached 14 mm, the presence of luteinizing hormone (LH) was monitored; when LH positivity was detected, blood samples were drawn to test follicle-stimulating hormone (FSH), LH, estradiol (E2) and testosterone (T) levels. Human chorionic gonadotropin (hCG, 10 000 U) was then injected to induce ovulation. RESULTS: The ovulation rate, stimulation follicle days, diameter of the biggest follicle on the day of LH positivity and the thickness of endometrium were all similar between the two groups (P>0.05). But in women receiving 5.0 mg letrozole, both the number of mature follicles and pregnancy rate were significantly higher than those in women having the half dose (P<0.05). The levels of FSH, LH, E2, and T on the third day of menstruation and on the day of HCG injection were similar between the two groups (P<0.05). CONCLUSION: Letrozole at the dose of 5.0 mg/day produces higher pregnancy rate and more mature follicles in fertile women with PCOS.