Characteristics and risk factors for death in HIV-positive talaromycosis marneffei patients with sepsis.

Objectives: This case-control study aimed to analyze the characteristics and risk factors for death in HIV-positive Talaromycosis marneffei (TSM) patients with sepsis. Methods: We retrospectively reviewed 173 AIDS patients diagnosed with TSM infection from January 1, 2013, to December 1, 2023, at Hangzhou Xixi Hospital. We collected and analyzed clinical characteristics, laboratory findings, bone marrow cytology results, treatment, and prognosis. Results: Out of 173 AIDS-TSM patients, 92 had sepsis while 81 did not. AIDS-TSM patients with sepsis have a higher in-hospital mortality rate (19.6 %) than non-sepsis patients (0 %). The SOFA score showed a significant association with in-hospital mortality in AIDS-TSM patients with sepsis (OR = 1.583, 95 % CI: 1.183-2.118, P = 0.002), indicating an almost linear relationship. After adjusting for the SOFA score, only hemoglobin (Hb) (OR = 0.971, 95 % CI: 0.943-1.000, P = 0.046), international normalized ratio (INR) (OR = 22.33, 95 % CI: 1.84-270.90, P = 0.015), and C-reactive protein (CRP) (OR = 1.014, 95 % CI: 1.001-1.027, P = 0.039) remained significantly associated with in-hospital mortality. The Receiver Operating Characteristic (ROC) curve of the SOFA score, INR, and CRP showed moderately good predictive performance for in-hospital mortality, while Hb had a low predictive performance. The Area Under Curve (AUC) values were 0.834, 0.820, 0.776, and 0.669, respectively. Conclusions: AIDS-TSM patients with sepsis have a higher mortality rate. Moreover, the SOFA score, along with Hb, INR, and CRP, are the risk factors for death in AIDS-TSM patients with sepsis.

Near-infrared fluorescence imaging of hepatocellular carcinoma cells regulated by ß-catenin signaling pathway.

Background: Near-infrared fluorescence (NIRF) imaging has recently emerged as a promising tool for noninvasive cancer imaging. However, lack of tumor sensitivity and specificity restricts the application of NIRF dyes in surgical navigation. Methods: Herein, we investigated the imaging features of NIRF dye MHI-148 and indocyanine green (ICG) in live cell imaging and xenograft nude mice models. TCGA dataset analysis and immunohistochemistry were conducted to investigate the expression of OATPs or ABCGs in hepatocellular carcinoma (HCC) tissues. OATPs or ABCGs were knocked down and overexpressed in HCC cells using transient transfection by siRNA and plasmids or stable transfection by lentivirus. Further, qRT-PCR ,Western blotting and the use of agonists or inhibitors targeting ß-catenin signaling pathway were applied to explore its important role in regulation of OATP2B1 and ABCG2 expression. Results: Here we demonstrated that NIRF dye MHI-148 was biocompatible as indocyanine green (ICG) but with higher imaging intensity and preferential uptake and retention in hepatocellular carcinoma (HCC) cells and tissues. Moreover, our data indicated that membrane transporters OATP2B1 and ABCG2, which regulated by ß-catenin signaling pathway, mediated tumor-specific accumulation and retention of MHI-148 in HCC cells. In addition, the treatment with ß-catenin inhibitor significantly enhanced the accumulation of MHI-148 in HCC tissues and improved the efficacy of tumor imaging with MHI-148 in vivo. Conclusions: Our study uncovers a mechanism that links the distribution and expression of the membrane transporters OATP2B1 and ABCG2 to the tumor-specific accumulation of MHI-148, and provides evidence supporting a regulating role of the ß-catenin signaling pathway in OATP2B1 and ABCG2- induced retention of MHI-148 inHCC tissues, and strategy targeting key components of MHI-148 transport machinery may be a potential approach to improve HCC imaging.

Targeting ß-glucans, vital components of the Pneumocystis cell wall.

ß-glucan is the most abundant polysaccharide in the cell wall of Pneumocystis jirovecii, which has attracted extensive attention because of its unique immunobiological characteristics. ß-glucan binds to various cell surface receptors, which produces an inflammatory response and accounts for its immune effects. A deeper comprehension of the processes by Pneumocystis ß-glucan recognizes its receptors, activates related signaling pathways, and regulates immunity as required. Such understanding will provide a basis for developing new therapies against Pneumocystis. Herein, we briefly review the structural composition of ß-glucans as a vital component of the Pneumocystis cell wall, the host immunity mediated by ß-glucans after their recognition, and discuss opportunities for the development of new strategies to combat Pneumocystis.

Impact of COVID-19 Risk Perception on Emotional Exhaustion among Chinese Hospitality Employees: The Mediating Effect of Job Insecurity.

This study aims to investigate the levels of COVID-19 risk perception (CVRP), job insecurity (JI), and emotional exhaustion (EE) among Chinese hospitality employees to examine the mediating effect of JI on the relationship between CVRP and EE. The moderating role of employee mindfulness (MF) and perceived employability (PE) have also be examined. Data were collected from 652 hospitality employees in Shandong and Jiangsu Province, China. We used structural equation modeling (SEM) to test the hypothesized relationship among the variables. Significant relationships were found between hospitality employees' CVRP and EE (ß = 0.103, p < 0.01), CVRP and JI (ß = 0.168, p < 0.001), and JI and EE (ß = 0.378, p < 0.001). According to the results, the higher level of the CVRP of hospitality employees, the higher level of the EE. In addition, results showed mediating effects of JI on the relationship between CVRP and EE. This study also found that MF buffered the positive relationship between CVRP and EE. Therefore, in the era of COVID-19, an effective support system at the organizational level is necessary to reduce JI and EE of hospitality employees.

Immune Characteristics of Patients with Coronavirus Disease 2019 (COVID-19).

Up to now, little is known about the detailed immune profiles of COVID-19 patients from admission to discharge. In this study we retrospectively reviewed the clinical and laboratory characteristics of 18 COVID-19 patients from January 30, 2020 to February 21, 2020. These patients were divided into two groups; group 1 had a severe acute respiratory syndrome coronavirus 2 nucleic acid-positive duration for more than 15 days (n = 6) and group 2 had a nucleic acid-positive duration for less than 15 days (n = 12). Group 1 patients had lower level of peripheral blood lymphocytes (0.40 vs. 0.78 ×109/L, p = 0.024) and serum potassium (3.36 vs. 3.79 mmol/L, p = 0.043) on admission but longer hospitalization days (23.17 vs. 15.75 days, p < 0.001) compared to Group 2 patients. Moreover, baseline level of lymphocytes (r = -0.62, p = 0.006) was negatively correlated with the nucleic acid-positive duration. Additionally, lymphocytes (420.83 vs. 1100.56 /µL), T cells (232.50 vs. 706.78 /µL), CD4+ T cells (114.67 vs. 410.44 /µL), and CD8+ T cells (94.83 vs. 257.44 /µL) in the peripheral blood analyzed by flow cytometry were significantly different between Group 1and Group 2. Furthermore, there was also a negative correlation between lymphocytes (r = -0.54, p = 0.038) or T cells (r = -0.55, p = 0.034) at diagnosis and the nucleic acid-positive duration, separately. In conclusion, the patients with nucleic acid-positive ≥ 15 days had significantly decreased lymphocytes, T cell and its subsets compared to those who remained positive for less than 15 days.

Characteristics and outcomes of acute-on-chronic liver failure patients with or without cirrhosis using two criteria.

The aim of the study was to identify the characteristics and outcomes in acute-on-chronic liver failure (ACLF) patients with or without cirrhosis using two criteria. Patients with acute deterioration of chronic hepatic disease or acute decompensation of cirrhosis were included retrospectively from April 10, 2016 to April 10, 2019. European Association for the Study of the Liver-chronic liver failure (EASL-CLIF) criterion except for consideration of cirrhosis and Chinese Group on the Study of Severe Hepatitis B (COSSH) criterion were used. Clinical features, laboratory data and survival curves were compared between the ACLF patients with and without cirrhosis. A total of 799 patients were included. Among them, 328 had COSSH and EASL ACLF, 197 had COSSH alone, and 104 had EASL alone. There were 11.6% more ACLF with COSSH criterion. Furthermore, EASL ACLF patients with non-cirrhosis vs. cirrhosis had different laboratory characteristics: ALT (423 vs. 154, p < 0.001), AST (303 vs. 157, p < 0.001), γ-GT (86 vs. 75, p < 0.01), and INR (2.7 vs. 2.6, p < 0.001) were significantly higher but creatinine (71 vs. 77, p < 0.01) were significantly lower; but importantly there was no statistical changes between non-cirrhosis and cirrhosis in EASL ACLF patients on 28-day (p = 0.398) and 90-day (p = 0.376) survival curves. However, 90-day (p = 0.030) survival curve was different between non-cirrhosis and cirrhosis in COSSH ACLF patients. COSSH ACLF score (auROC = 0.778 or 0.792, 95%CI 0.706-0.839 or 0.721-0.851) displayed the better prognostic ability for EASL ACLF patients with non-cirrhosis, but CLIF-C ACLF score (auROC = 0.757 or 0.796, 95%CI 0.701-0.807 or 0.743-0.843) still was the best prognostic scoring system in EASL ACLF patients with cirrhosis. In conclusions, EASL definition exhibited better performance on homogeneous identification of ACLF regardless of cirrhosis or non-cirrhosis. And COSSH ACLF score displayed the better prognostic ability for EASL ACLF patients without cirrhosis.

A Pilot Study of Echinocandin Combination with Trimethoprim/Sulfamethoxazole and Clindamycin for the Treatment of AIDS Patients with Pneumocystis Pneumonia.

BACKGROUND AND OBJECTIVES: Pneumocystis pneumonia (PCP) is a common opportunistic infection in acquired immune deficiency syndrome (AIDS) patients that continues to result in a high mortality rate. To develop a better treatment strategy and improve PCP prognosis, a cohort study was conducted to evaluate the therapeutic potential of echinocandin treatment for AIDS patients with PCP (AIDS-PCP). METHODS: The AIDS-PCP patients were analyzed in our retrospective cohort study that were hospitalized in The First Affiliated Hospital of Zhejiang University during 2013-2018. The antifungal effects of echinocandins were evaluated in two subgroups that were classified by oxygenation as a proxy for the disease state: PaO2/FiO2 > 200 mmHg and PaO2/FiO2 ≤ 200 mmHg. Intergroup comparisons and survival curves were used to evaluate the effectiveness of the two AIDS-PCP treatment regimens. RESULTS: During the follow-up, 182 AIDS-PCP patients were diagnosed and analyzed in the study. After excluding 55 patients with other superinfections and five patients that were treated with HAART, the remaining 122 patients were enrolled in the study. The group treated with echinocandins combined with trimethoprim-sulfamethoxazole (TMP-SMZ) and clindamycin exhibited a lower mortality rate (9.62%, 5/52) than did the group with TMP-SMZ and clindamycin treatment (20%, 14/70). For AIDS-PCP patients in the PaO2/FiO2 > 200 mmHg subgroup, treatment with echinocandins combined with TMP-SMZ and clindamycin significantly reduced their mortality rate (4.44% (2/45) vs. 18.18% (10/55), P = 0.035). CONCLUSION: The results of this study indicate that treatment with echinocandins in combination with the standard TMP-SMZ and clindamycin regimen can improve the prognosis and reduce the mortality rate in patients with mild to moderate AIDS-PCP disease.

Polymorphisms involving the Pneumocystis jirovecii-related genes in AIDS patients in eastern China.

OBJECTIVE: To investigate the genetic polymorphisms of mitochondrial large ribosomal subunit (mtLSU)-rRNA, dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), cytochrome b (CYB), and superoxide dismutase (SOD) genes and its correlation with clinical outcomes of Pneumocystis jirovecii pneumonia in acquired immune deficiency(AIDS) patients. METHODS: Eighty AIDS patients with P. jirovecii pneumonia that were admitted to our hospital from 2016 to 2018 were included in this study. Their demographic information and clinical data were collected, as well as corresponding saliva specimens for PCR and sequencing of mtLSU-rRNA, DHFR, DHPS, CYB, and SOD genes to analyze genetic polymorphisms, different polymorphic combinations, and clinical outcomes. RESULTS: Of the 80 saliva specimens, mtLSU-rRNA was successfully amplified and sequenced in 30 cases; CYB was successfully amplified and sequenced in 26 cases; and SOD, DHFR, and DHPS were successfully amplified and sequenced in 18 cases. These results indicate that The mtLSU-rRNA, CYB, and SOD genes were highly polymorphic. mt85T and CYB1 were the variants dominantly detected at the mtLSU-rRNA and CYB loci, respectively. The SOD1 and SOD2 variants (each in 50% of the cases) were detected at the SOD locus. Among the 18 cases that were successfully amplified and sequenced for DHFR and DHPS, three DHFR nonsense mutations and no DHPS mutation were observed. The mt85C, CYB1, SOD1, and DHFR312T genes harbored common polymorphisms (n = 4; 22.22%) and the mt85T, CYB1, SOD1, DHFR312T genes were associated with poor clinical outcomes. CONCLUSION: The types of genetic polymorphisms and polymorphic combinations of mtLSU-rRNA, DHFR, DHPS, CYB, and SOD in P. jirovecii were related to the clinical outcomes of patients with P. jirovecii pneumonia in Zhejiang Province, China.

Role of macrophages in experimental liver injury and repair in mice.

Liver macrophages make up the largest proportion of tissue macrophages in the host and consist of two dissimilar groups: Kupffer cells (KCs) and monocyte-derived macrophages (MoMø). As the liver is injured, KCs sense the injury and initiate inflammatory cascades mediated by the release of inflammatory cytokines and chemokines. Subsequently, inflammatory monocytes accumulate in the liver via chemokine-chemokine receptor interactions, resulting in massive inflammatory MoMø infiltration. When live r injury ceases, restorative macrophages, derived from recruited inflammatory monocytes (lymphocyte antigen 6 complex, locus Chi monocytes), promote the resolution of hepatic damage and fibrosis. Consequently, a large number of studies have assessed the mechanisms by which liver macrophages exert their opposing functions at different time-points during liver injury. The present review primarily focuses on the diverse functions of macrophages in experimental liver injury, fibrosis and repair in mice and illustrates how macrophages may be targeted to treat liver disease.

Activation of the kynurenine pathway is associated with poor outcome in Pneumocystis pneumonia patients infected with HIV: results of 2 months cohort study.

BACKGROUND: Indoleamine 2, 3-dioxygenase (IDO) is a key enzyme in the degradation of tryptophan (Trp) to kynurenine (Kyn). We measured IDO activity as the Kyn to Trp ratio, and investigated whether IDO could be used to assess prognosis of acquired immune deficiency Sydrome (AIDS) patients with pneumocystis pneumonia (PCP). METHODS: The Kyn and Trp concentration were measured by UPLC-MS/MS in plasma samples. A total of 49 AIDS-PCP patients were included in the analysis. Clinical characteristics and Kyn/Trp ratio were compared between survivors and non-survivors. RESULTS: Kyn/Trp ratio was significantly lower after anti-PCP treatment in AIDS patients with PCP (P < 0.0001). Plasma Kyn/Trp ratio was higher in patients with PaO2/FiO2 ≤ 300 mmHg than in those with PaO2/FiO2 > 300 mmHg (P = 0.007). Kyn/Trp ratio, D-dimer and CRP showed much higher AUC for predicting death of AIDS-PCP patients. Kyn/Trp ratio was useful for predicting the mortality of AIDS-PCP due to a significantly higher Kyn/Trp ratio in the non-survivors (P = 0.002). And the high Kyn/Trp ratio group had higher mortality rate than low Kyn/Trp group (32.1% vs. 9.1%, respectively, p = 0.024). CONCLUSION: Activation of the kynurenine pathway is associated with the severity and fatal outcomes of AIDS patients with pneumocystis pneumonia.

Characteristics of Intestinal Microecology during Mesenchymal Stem Cell-Based Therapy for Mouse Acute Liver Injury.

BACKGROUND: The mechanisms of mesenchymal stem cell (MSC) transplantation to protect against acute liver injury have been well studied within the liver. However, the associated changes in the intestinal microbiota during this process are poorly understood. METHODS: In this study, compact bone-derived MSCs were injected into mice after carbon tetrachloride (CCl4) administration. Potential curative effect of MSC was evaluated by survival rate and biochemical and pathological results. Overall structural changes of microbial communities and alterations in the intestinal microbiota were assessed by sequenced 16S rRNA amplicon libraries from the contents of the cecum and colon. RESULTS: MSCs significantly reduced the serum levels of aspartate transaminase and alanine transaminase and improved the histopathology and survival rate. Lower expression and discontinuous staining of zonula occludens, as well as disrupted tight junctions, were observed in CCl4-treated mice at 48 h compared with MSC-transplanted mice. Moreover, MSC transplantation to the liver leads to intestinal microbiota changes that were reflected in the decreased abundance of Bacteroidetes S24-7 and Bacteroidaceae and increased abundance of Firmicutes Clostridiales, Ruminococcaceae, and Lactobacillus at the initial time point compared with that in CCl4-treated mice. In addition, phylogenetic investigation of communities by the reconstruction of unobserved states (PICRUSt) based on the Greengenes database revealed functional biomarkers of MSC-transplanted mice involved in cell motility, signal transduction, membrane transport, transcription, and metabolism of lipids, cofactors, vitamins, terpenoids, and polyketides, as well as xenobiotics. CONCLUSION: The initial alterations in the Firmicutes/Bacteroidetes ratio, which resulted from MSC infusion to the liver, maintain intestinal mucosal biology and homeostasis that may be beneficial to liver repair.

The presence of Pneumocystis jirovecii DNA in plasma is associated with a higher mortality rate in patients with AIDS-associated Pneumocystis pneumonia.

To examine the relationship between Pneumocystis jirovecii DNA (PJ-DNA) levels in blood from AIDS-associated Pneumocystis pneumonia (AIDS-PCP) and mortality, and to correlate mitochondrial large subunit rRNA (mtLSUrRNA) gene polymorphism with mortality, we performed a retrospective study including AIDS-PCP patients between 2014 and 2016 from one hospital in China. PJ-DNA in plasma was measured by nested polymerase chain reaction (PCR) of the mtLSUrRNA gene and in positive specimens we further detected the level of PJ-DNA using qPCR. Polymorphisms were observed at two positions (85 and 248) of the mtLSUrRNA gene by sequencing. The PJ-DNA positivity rate for survivors and nonsurvivors was 13.64% (9/66) and 78.57% (11/14) (P ≤ .001), respectively. Using multivariate analysis, we found that lactate dehydrogenase, PaO2, albumin and PJ-positive in blood were independent predictors of death (P = .011; P = .042; P = .01; P ≤ .001, respectively). The PJ-DNA level in the nonsurvivor group (n = 11) was higher than that of the survivor group (n = 9) (54610.3copies/ ml vs. 934.5 copies/ml, P = .006). Nine had genotype 1, and 88.89% (8/9) patients died. Of nine with genotype 3, 11.11% (1/9) died (P = .003). In conclusion, high PJ-DNA level detected by analyzing plasma and mtLSUrRNA genotype 1 are strongly associated with death in AIDS-PCP patients.

The Impact of GFP Reporter Gene Transduction and Expression on Metabolomics of Placental Mesenchymal Stem Cells Determined by UHPLC-Q/TOF-MS.

INTRODUCTION: Green fluorescent protein (GFP) is widely used as a reporter gene in regenerative medicine research to label and track stem cells. Here, we examined whether expressing GFP gene may impact the metabolism of human placental mesenchymal stem cells (hPMSCs). METHODS: The GFP gene was transduced into hPMSCs using lentiviral-based infection to establish GFP+hPMSCs. A sensitive 13C/12C-dansyl labeling LC-MS method targeting the amine/phenol submetabolome was used for in-depth cell metabolome profiling. RESULTS: A total of 1151 peak pairs or metabolites were detected from 12 LC-MS runs. Principal component analysis and partial least squares discriminant analysis showed poor separation, and the volcano plots demonstrated that most of the metabolites were not significantly changed when hPMSCs were tagged with GFP. Overall, 739 metabolites were positively or putatively identified. Only 11 metabolites showed significant changes. Metabolic pathway analyses indicated that three of the identified metabolites were involved in nine pathways. However, these metabolites are unlikely to have a large impact on the metabolic pathways due to their nonessential roles and limited hits in pathway analysis. CONCLUSION: This study indicated that the expression of ectopic GFP reporter gene did not significantly alter the metabolomics pathways covered by the amine/phenol submetabolome.

Therapeutic Effect and Location of GFP-Labeled Placental Mesenchymal Stem Cells on Hepatic Fibrosis in Rats.

Background. Liver fibrosis is a chronic progressive liver disease, but no established effective treatment exists except for liver transplantation. The present study was designed to investigate the effect of human placenta mesenchymal stem cells (hPMSCs) expressing green fluorescent protein (GFP) on carbon tetrachloride- (CCl4-) induced liver fibrosis in rats. Methods. Liver fibrosis was induced by subcutaneous injection with CCl4; hPMSCs were directly transplanted into rats through the caudal vein. The therapeutic efficacy of hPMSCs on liver fibrosis was measured by liver function tests, liver elastography, histopathology, Masson's trichrome and Sirius red staining, and immunohistochemical studies. The expression levels of fibrotic markers, transforming growth factor ß1 (TGF-ß1) and α-smooth muscle actin (α-SMA), were assessed using real-time polymerase chain reaction. Results. We demonstrated that liver fibrosis was significantly dampened in the hPMSC transplantation group according to the Laennec fibrosis scoring system and histological data. The Sirius red-stained collagen area and the elastography score were significantly reduced in the hPMSC-treated group. Meanwhile, hPMSC administration significantly decreased TGF-ß1 and α-SMA expression and enhanced liver functions in CCl4-induced fibrotic rats. Conclusion. This study indicates that transplantation of hPMSCs could repair liver fibrosis induced by CCl4 in rats, which may serve as a valuable therapeutic approach to treat liver diseases.

Homology modeling and molecular dynamics simulation of the HIF2α degradation-related HIF2α-VHL complex.

BACKGROUND: Hypoxia-inducible factor 2 alpha (HIF2α), prolyl hydroxylase domain protein 2 (PHD2), and the von Hippel Lindau tumor suppressor protein (pVHL) are three principal proteins in the oxygen-sensing pathway. Under normoxic conditions, a conserved proline in HIF2α is hydroxylated by PHD2 in an oxygen-dependent manner, and then pVHL binds and promotes the degradation of HIF2α. However, the crystal structure of the HIF2α-pVHL complex has not yet been established, and this has limited research on the interaction between HIF and pVHL. Here, we constructed a structural model of a 23-residue HIF2α peptide (528-550)-pVHL-ElonginB-ElonginC complex by using homology modeling and molecular dynamics simulations. We also applied these methods to HIF2α mutants (HYP531PRO, F540L, A530 V, A530T, and G537R) to reveal structural defects that explain how these mutations weaken the interaction with pVHL. METHODS: Homology modeling and molecular dynamics simulations were used to construct a three-dimensional (3D) structural model of the HIF2α-VHL complex. Subsequently, MolProbity, an active validation tool, was used to analyze the reliability of the model. Molecular mechanics energies combined with the generalized Born and surface area continuum solvation (MM-GBSA) and solvated interaction energy (SIE) methods were used to calculate the binding free energy between HIF2a and pVHL, and the stability of the simulation system was evaluated by using root mean square deviation (RMSD) analysis. We also determined the secondary structure of the system by using the definition of secondary structure of proteins (DSSP) algorithm. Finally, we investigated the structural significance of specific point mutations known to have clinical implications. RESULTS: We established a reliable structural model of the HIF2α-pVHL complex, which is similar to the crystal structure of HIF1α in 1LQB. Furthermore, we compared the structural model of the HIF2α-pVHL complex and the HIF2α (HYP531P, F540L, A530V, A530T, and G537R)-pVHL mutants on the basis of RMSD, DSSP, binding free energy, and hydrogen bonding. The experimental data indicate that the stability of the structural model of the HIF2α-pVHL complex is higher than that of the mutants, consistently with clinical observations. CONCLUSIONS: The structural model of the HIF2α-pVHL complex presented in this study enhances understanding of how HIF2α is captured by pVHL. Moreover, the important contact amino acids that we identified may be useful in the development of drugs to treat HIF2a-related diseases.

Analysis on pollutant accidental discharge in Zhoushan Islands, China.

The water quality diffusion and transport around archipelago have their own uniqueness and complexity. On the basis of multinest 2D mathematical model for currents around Zhoushan Islands, model for water quality prediction was built. The pollutants discharge of Xiaogan Island was taken into consideration and mathematical model for pollutant diffusion and transport in accident discharge was studied. The influence on water quality in different discharge intensity was calculated, which provided scientific basis for the control results. It was observed that the concentration contours of COD(Mn) at 0.03 km(2) in three conditions corresponded to standard discharge at 0.90 mg l(-1), accidental discharge at 1.02 mg l(-1)and extreme discharge at 1.42 mg l(-1), respectively. Although discharge point locates between the archipelago, diffusion of pollutants is rapid for the fast-flowing waters ofZhoushan Islands, that provides good diffusion conditions.