Hippocampal volume and resting-state functional connectivity on magnetic resonance imaging in patients with Parkinson and depression.

Background: Recent structural and functional imaging studies of depression in Parkinson disease (DPD) have failed to reveal the relevant mechanism, and relatively few studies have been conducted on limbic systems such as the hippocampus. This study thus aimed to gain new insights into the pathogenesis of DPD by detecting the changes in the hippocampal structure and the resting-state functional connectivity (FC) of patients with DPD. Methods: This study included 30 patients with DPD (DPD group), 30 patients with nondepressed Parkinson disease (NDPD; NDPD group), and 30 normal controls (NCs; NC group) with no significant age or gender differences with the DPD group. The Hamilton Depression Rating Scale (HAMD) and three-dimensional T1-weighted imaging and blood oxygen level-dependent imaging data of all patients were collected. The hippocampal volumes were measured using MATLAB software (MathWorks). The correlation between hippocampal volume and the HAMD score in the DPD group was analyzed with Pearson correlation coefficient. The bilateral hippocampi were used as the regions of interest and as the seed points for FC. FC analysis was performed between the preprocessed functional data of the whole brain and the two seed points with Data Processing Assistant for Resting-State and Statistical Parametric Mapping 8 software, respectively. The correlation between FC and HAMD scores in the patients with DPD was determined using partial correlation analysis. Results: Compared with those in the NC group and the NDPD group, the bilateral hippocampal volumes in the DPD group were significantly decreased (P<0.05). There was a negative correlation between the bilateral hippocampal volume and the HAMD score in the DPD group (P<0.05). Compared with that of the NDPD group, the FC of the right hippocampus with the right occipital lobe and left precuneus was reduced in the DPD group. In the DPD group, the FC values of the right hippocampus, right occipital lobe, and left anterior cuneiform lobe were negatively correlated with HAMD scores. Conclusions: The volume of bilateral hippocampi in patients with DPD is significantly decreased and negatively correlated with the severity of depressive disorder. The weakened FC of the right hippocampus to the right occipital lobe and the left precuneus may play an important role in the neurological basis of DPD.

Apatinib Combined with Local Irradiation Leads to Systemic Tumor Control via Reversal of Immunosuppressive Tumor Microenvironment in Lung Cancer.

PURPOSE: This study aimed to investigate the potential systemic antitumor effects of stereotactic ablative radiotherapy (SABR) and apatinib (a novel vascular endothelial growth factor receptor 2 inhibitor) via reversing the immunosuppressive tumor microenvironment for lung carcinoma. MATERIALS AND METHODS: Lewis lung cancer cells were injected into C57BL/6 mice in the left hindlimb (primary tumor; irradiated) and in the right flank (secondary tumor; nonirradiated). When both tumors grew to the touchable size, mice were randomly divided into eight treatment groups. These groups received normal saline or three distinct doses of apatinib (50 mg/kg, 150 mg/kg, and 200 mg/kg) daily for 7 days, in combination with a single dose of 15 Gy radiotherapy or not to the primary tumor. The further tumor growth/regression of mice were followed and observed. RESULTS: For the single 15 Gy modality, tumor growth delay could only be observed at the primary tumor. When combining SABR and apatinib 200 mg/kg, significant retardation of both primary and secondary tumor growth could be observed, indicated an abscopal effect was induced. Mechanism analysis suggested that programmed death-ligand 1 expression increased with SABR was counteract by additional apatinib therapy. Furthermore, when apatinib was combined with SABR, the composition of immune cells could be changed. More importantly, this two-pronged approach evoked tumor antigen-specific immune responses and the mice were resistant to another tumor rechallenge, finally, long-term survival was improved. CONCLUSION: Our results suggested that the tumor microenvironment could be managed with apatinib, which was effective in eliciting an abscopal effect induced by SABR.

[Toxicity of PM2.5 Based on a Battery of Bioassays].

To accurately evaluate the biotoxicity of PM2.5, PM2.5 samples from winter fog-haze days, winter normal days, and summer days in Changzhou were selected for evaluation based on the acute toxicity of luminescent bacteria and zebrafish embryos and the cytotoxicity of human lung adenocarcinoma cells in vitro (A549). The three atmospheric conditions and the physical and chemical indicators were also evaluated using correlation analysis. The PM2.5 samples showed either acute or developmental toxicity during all three periods. The toxicity unit (TU) of the luminescent bacteria for the winter fog-haze days, winter normal days, and summer days were 1.74 (toxic), 1.19 (toxic), and 0.92 (slightly toxic), respectively. The maximum TU of the zebrafish embryos was for winter normal days (TU=1.14, toxic) followed by winter fog-haze days (TU=0.79, slightly toxic), and summer days (TU=0, non-toxic). The highest TU of A549 was for winter fog-haze days (TU=0.61, toxic) followed by summer days (TU=0.38, toxic) and winter normal days (TU=0.31, toxic). With respect to developmental toxicity, with the exception of summer day samples, the PM2.5 samples from the other two periods had detrimental effects on the development of zebrafish embryos, mainly showing pericardial edema, a bent notochord, and tail deformity. The average toxicity (AvTx), toxic print (TxPr), and most sensitive test (MST) indices showed that the PM2.5 samples from winter fog-haze days and winter normal days exhibited toxicity, while samples from the summer days showed slight toxicity; PM2.5 samples from winter fog-haze days had the highest level of comprehensive toxicity. In addition, luminescent bacteria were the most sensitive to PM2.5 samples, followed by zebrafish embryos and A549. The results of chemical analysis and biological toxicity tests show that the pollutants contained in PM2.5 have a biological toxicity effect, which can provide a basis for the comprehensive assessment of PM2.5 biological toxicity and human health risks.

Apatinib combined with docetaxel as a salvage treatment for metastatic esophageal squamous cancer: a case report.

The first-line treatment for metastatic esophageal squamous cell cancer (ESCC) is a platinum- or fluorouracil-based agent, followed by later treatment with taxanes or irinotecan. However, there is still no standard third-line treatment for patients with metastatic ESCC. We present a 62-year-old man initially diagnosed with locally advanced ESCC. After esophagectomy, the patient was administrated with six cycles of docetaxel and cisplatin combined with radiotherapy. After 8.0 months, computed tomography showed the left cervical lymph node metastasis. However, the metastatic lymph node was not significantly shrunk after locally palliative radiotherapy and the patient was intolerant of irinotecan as second-line systemic therapy. Then, the patient was rechallenged with six cycles of docetaxel combined with apatinib (an oral tyrosine kinase inhibitor to vascular endothelial growth factor receptor 2 [VEGFR2]), followed by single dose of apatinib as maintenance therapy. According to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 standard, partial response was achieved in this case after treating with docetaxel combined with apatinib. Now, the progression-free survival of this patient has been 7.5 months. After administrating with apatinib for 2 weeks, hypertension (grade III) was observed. Thus, the dose of apatinib was decreased from 850 to 500 mg and then the adverse effects were controllable and tolerable. In conclusion, apatinib with concurrent docetaxel provided potential efficacy as a salvage treatment for patients with metastatic ESCC. To our knowledge, this is the first case of ESCC who responded to apatinib combined with docetaxel.

Enhanced antiproliferative activity of antibody-functionalized polymeric nanoparticles for targeted delivery of anti-miR-21 to HER2 positive gastric cancer.

MiR-21 is an oncogenic miR frequently elevated in gastric cancer. Overexpression of miR-21 decreases the sensitivity of gastric cancer cells to trastuzumab, which is a humanized monoclonal antibody targeting human epidermal growth factor receptor 2. However, optimization of miRNA or its anti-miRNA oligonucleotides (AMOs) for delivery is a challenge. Receptor-mediated endocytosis plays a crucial role in the delivery of biotherapeutics including AMOs. This study is a continuation of our earlier findings involving poly(ε-caprolactone) (PCL)-poly (ethylene glycol) (PEG) nanoparticles (PEG-PCL NPs), which were coated with trastuzumab to target gastric cancer cells with HER2 receptor over-expression using anti-miRNA-21 antisense oligonucleotides (AMO-21). The antibody conjugates (HER-PEG-PCL NPs) act against target cells via antibody-dependent mechanisms and also based on encapsutalated AMO-21. X-ray photoelectron spectroscopy validated the presence of trastuzumab on NP surface. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a stable antibody expression. The cell line specificity, cellular uptake, AMO-21 delivery, and cytotoxicity of the HER-PEG-PCL NPs were investigated. We found that the antibody conjugates significantly enhanced the cellular uptake of NPs. The HER-PEG-PCL NPs effectively suppressed the target miRNA expression in gastric cancer cells, which further up-regulated phosphatase and tensin homolog (PTEN). As a result, the sensitivity of HER2-expressing gastric cancer cells to trastuzumab was enhanced. The approach enhances the targeting by trastuzumab as well as antibody-dependent cellular cytotoxicity of immune effector cells. The antitumor effects of AMO-21-HER-PEG-PCL NPs were compared with trastuzumab in xenograft gastric cancer mice. The results provide insight into the biological and clinical potential of targeted AMO-21 delivery using modified trastuzumab for gastric cancer treatment.

Study on lung cancer cells expressing VEGFR2 and the impact on the effect of RHES combined with radiotherapy in the treatment of brain metastases.

INTRODUCTION: Brain metastases are often accompanied by edema. Endostatin therapy can prevent tumor tissue edema. Therefore, we investigated the therapeutic effects of endostatin combined with radiotherapy in the treatment of brain metastases of non-small cell lung cancer (NSCLC) and assessed the relations between the effect and vascular endothelial growth factor receptor 2 (VEGFR2) expression. PATIENTS AND METHODS: Eighty patients with brain metastases of NSCLC were randomly divided into a combination therapy group and a radiotherapy-alone group, each group with 40 patients. The short-term effective rate, overall survival time, cerebral edema index, and adverse reactions were observed, and the expressions of VEGFR2 protein and KDR gene in primary lesions were detected via immunohistochemical methods and fluorescence in-situ hybridization (FISH) in all patients. RESULTS: Compared with the radiotherapy-alone group, brain edema was significantly relieved (P = .003) and there were no marked adverse reactions in the combination therapy group. Regarding the short-term effective rate, there was no statistical significance in the total population (n = 80, 90% vs. 75%, P = .07), but there was statistical significance in cases of positive VEGFR2 (93% vs. 67.7%, P = .012) or positive KDR gene (94.4% vs. 47.3%, P = .002) in both groups. For overall survival time, there was no statistical significance in total population (n = 80, P = .35), positive VEGFR2 patients (P = .109), and positive KDR gene patients (P = .147). CONCLUSION: Compared with radiotherapy alone, endostatin combined with radiotherapy can relieve brain edema in patients with brain metastases of NSCLC and can obtain a better short-term effective rate in patients with positive VEGFR2 or positive KDR gene, but endostatin therapy does not significantly improve overall survival time.

Enhanced radioresponse with a novel recombinant human endostatin protein via tumor vasculature remodeling: experimental and clinical evidence.

PURPOSE: This study aimed to examine the effect of the novel recombinant human endostatin (rh-Endo) protein on tumor vasculature, and to explore and evaluate the optimal scheduling of rh-Endo and radiotherapy (RT). METHODS: Tumor-perfusion parameters and hypoxia were monitored after rh-Endo treatment in 10 non-small cell lung-cancer (NSCLC) patients. Eight-week female C57BL/6J mice were randomized to receive rh-Endo or control (saline) once daily for 12 days when Lewis lung carcinoma (LLC) reached approximately 100-150 mm(3). On planned days, tumors were measured for cell apoptosis, microvessel density, pericytes, blood-vessel morphology, and tumor hypoxia. The tumor response under different combinations of rh-Endo and RT schedules was evaluated. RESULTS: Tumor hypoxia was significantly reduced 5 days after rh-Endo in NSCLC patients, and a similar result was found in the LLC mouse model. The anti-tumor effect was markedly enhanced when RT was administered within the remodeling period compared to any other treatment schedule. rh-Endo treatment remodeled the tumor vasculature after 5 days by reducing microvessel density and increasing pericytic coverage of the vessel endothelium. CONCLUSION: This study demonstrated decreased hypoxia in animals and patients upon rh-Endo treatment, which also enhanced the radioresponse within the vasculature-remodeling period. The optimal clinical combination of rh-Endo and RT warrants further investigation.

Enhancement of recombinant human endostatin on the radiosensitivity of human pulmonary adenocarcinoma A549 cells and its mechanism.

We observed the effects of endostar on the radiosensitivity of pulmonary adenocarcinoma A549 cells and found that endostar inhibited A549 cell growth under normoxia and hypoxia in time and dose-dependent manners; the D(0) and D(q) values in control and endostar groups were (1.36 and 1.30) versus (1.019 and 1.015) under normoxia and (1.693 and 1.39) versus (2.453 and 1.026) under hypoxia, respectively; SER was 1.04 under normoxia and 1.22 under hypoxia in endostar group; under normoxia, the apoptosis rates in control, radiotherapy, endostar and combination groups were 15.9 ± 0.57%, 42.7 ± 0.37%, 19.9 ± 0.48%, and 41.5 ± 0.38%, respectively, with no significant difference between combination and radiotherapy groups; there was significant difference in G(2)/M phase cells between combination and radiotherapy groups (P = 0.028); under hypoxia, the apoptosis rates in the four groups were 16.7 ± 0.67%, 30.1 ± 0.95%, 26.7 ± 0.62%, and 36.3 ± 0.71%, respectively, with significant difference between combination and radiotherapy groups; G(2)/M phase cells were higher in combination group than radiotherapy group (P = 0.000); G(2)/M phase cells were higher in hypoxic combination group than in normoxic combination group (P = 0.003). Based on these results, we conclude that under hypoxia, endostar can enhance the radiosensitivity of A549 cells through G(2)/M arrest.

Clinical study on the recombinant human endostatin regarding improving the blood perfusion and hypoxia of non-small-cell lung cancer.

OBJECTIVE: To observe the dynamic changes of blood perfusion and hypoxic status with CT perfusion imaging and hypoxia imaging in patients of non-small-cell lung cancer (NSCLC) who were treated with recombinant human endostatin (RHES). METHODS: Fifteen previously untreated patients with histologically or cytologically confirmed NSCLC were enrolled. They were randomly divided into research group (n=10) and negative control group (n=5). The patients of the research group continuously used RHES for ten days, and simultaneously had CT perfusion imaging and hypoxia imaging performed on days 1, 5 and 10, respectively. The remaining 5(control) only had CT perfusion imaging and hypoxia imaging, without using RHES, on days 1, 5 and 10, respectively. According to the above results, we could obtain a "time window" during which RHES improves blood perfusion and hypoxia of lung cancer. RESULTS: In the research group, after using RHES, capillary permeability surface (PS) and tumour to normal tissue (T/N) decreased at first, and then increased. Their lowest points occurred on about the fifth day with statistical significance compared with the first day (T/N, p=0.00; PS, p<0.01). Blood flow (BF) was first increased and then decreased. Its highest point occurred on about the fifth day with statistical significance compared with the first and tenth day (all p<0.01). The PS, BF and T/N peaked on the fifth day in the research group with statistical significance compared with the negative control group as well (all p<0.01). The above results suggested that RHES's "time window" was within about one week after administration. CONCLUSION: RHES's "time window" is within about one week after administration, which provides an important experimental basis for combining RHES with radiotherapy in human tumours.

Preliminary clinical study of weekly recombinant human endostatin as a hypoxic tumour cell radiosensitiser combined with radiotherapy in the treatment of NSCLC.

OBJECTIVE: To investigate the clinical effects and adverse effects of weekly recombinant human endostatin (RHES) as a hypoxic tumour cell radiosensitiser combined with radiotherapy in the treatment of non-small-cell lung cancer (NSCLC). METHODS: Fifty hypoxia-positive cases of pathology-diagnosed NSCLC (stage I-III) were randomly divided into a RHES+radiotherapy group (25 cases) and a radiotherapy alone group (25 cases). Intensity-modulated radiotherapy (IMRT) with a total dose of 60 Gy/30F/6W was adopted in the two groups. Target area included primary foci and metastatic lymph nodes. In the RHES+radiotherapy group, RHES (15 mg/day) was intravenously given during the first week. The therapeutic effects and adverse reactions were evaluated after treatment. RESULTS: In the RHES+radiotherapy and radiotherapy alone groups, the total effective rates (CR+PR) were 80% and 44% (χ(2)=6.87, p=0.009), respectively. The one-year and two-year local control rates were (78.9±8.4)% and (68.1±7.8)% (p=0.027), and (63.6±7.2)% and (43.4±5.7)% (p=0.022), respectively. The median progression-free survival was (21.1±0.97) and (16.5±0.95) months, respectively. The one-year and two-year overall survival rates were (83.3±7.2)% and (76.6±9.3)% (p=0.247), and (46.3±2.4)% and (37.6±9.1)% (p=0.218), respectively. CONCLUSION: RHES combined with radiotherapy within the first week has better short-term therapeutic effects and local control rate, and no severe adverse reactions in treatment of NSCLC. However, it failed to significantly improve the one-year and two-year overall survival rates.

Updating advances on recombinant human endostatin combined with radiotherapy for non-small cell lung cancer with brain metastasis.

Brain metastases (BM) heavily affects the prognosis of advanced non-small cell lung cancer (NSCLC). Although whole-brain radiotherapy remains the mainstream therapy for BM caused by NSCLC, the effectiveness is unsatisfactory. Endostar, a recombinant human endostatin (RHES), has shown certain therapeutic effect on advanced NSCLC. This article reviews the feasibility of Endostar combined with radiotherapy in the treatment of BM caused by NSCLC.

Effect of recombinant human endostatin on radiosensitivity in patients with non-small-cell lung cancer.

PURPOSE: To observe the effects of recombinant human endostatin (RHES) on the radiosensitivity of non-small cell lung cancer (NSCLC). METHODS AND MATERIALS: First, 10 hypoxia-positive cases of pathology-diagnosed NSCLC selected from 15 patients were used to determine the normalization window, a period during which RHES improves NSCLC hypoxia. Second, 50 hypoxia-positive cases of pathology-diagnosed NSCLC (Stages I-III) were randomly divided into a RHES plus radiotherapy group (25 cases) and a radiotherapy-alone group (25 cases). Intensity = modulated radiotherapy with a total dose of 60 Gy in 30 fractions for 6 weeks was adopted in the two groups. The target area included primary foci and metastatic lymph nodes. In the RHES plus radiotherapy group, RHES (15 mg/day) was intravenously given during the normalization window. RESULTS: After RHES administration, the tumor-to=normal tissue radioactivity ratio and capillary permeability surface were first decreased and then increased, with their lowest points on the fifth day compared with the first day (all p < 0.01). Blood flow was first increased and then decreased, with the highest point on the fifth day, compared with the first and tenth day (all p < 0.01). In the RHES plus radiotherapy group and the radiotherapy-alone group, the total effective rates (complete response plus partial response) were 80% and 44% (p = 0.009), respectively. The median survival times were 21.1 ± 0.97 months and 16.5 ± 0.95 months (p  = 0.004), respectively. The 1-year and 2-year local control rates were 78.9 ± 8.4% and 68.1 ± 7.8% (p = 0.027) and 63.6 ± 7.2% and 43.4 ± 5.7% (p = 0.022), respectively. The 1-year and 2-year overall survival rates were 83.3 ± 7.2% and 76.6 ± 9.3% (p = 0.247) and 46.3 ± 2.4% and 37.6 ± 9.1% (p = 0.218), respectively. CONCLUSION: The RHES normalization window is within about 1 week after administration. RHES combined with radiotherapy within the normalization window has better short-term therapeutic effects and local control rates and no severe adverse reactions in the treatment of NSCLC, but it failed to significantly improve the 1-year and 3-year overall survival rates.

Pathobiologic implications of methylation and expression status of Runx3 and CHFR genes in gastric cancer.

Runx3 and CHFR genes were defined as tumor suppressor genes in gastric cancer (GC) recently. This paper was to investigate the roles of methylation and expression status of Runx3 and CHFR genes in GC patients. Methylation-specific polymerase chain reaction (MSP) and bisulfite DNA sequencing (BSP) were used to detect methylation status of Runx3 and CHFR genes in GC patients. The expression of Runx3 and CHFR in GC patients was analyzed by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical analysis. The expression of the protein and mRNA decreased remarkably in the patients with aberrant promoter methylation of Runx3 and CHFR genes. The methylation status of Runx3 and CHFR were inversely related to the tumor size, tumor invasion depth and tumor differentiation in GC patients. Moreover, the protein expression of Runx3 and CHFR were significantly correlated with tumor invasion depth and tumor differentiation, respectively. Aberrant promoter methylation of Runx3 and CHFR genes may be involved in the carcinogenesis and development of GC and may provide useful clues for the prediction of the malignant behaviors of GC.

Inhibitory effect of radiotherapy combined with weekly recombinant human endostatin on the human pulmonary adenocarcinoma A549 xenografts in nude mice.

The aim of this study was to investigate the inhibitory effect of radiotherapy combined with weekly recombinant human endostatin (RHES) on the human pulmonary adenocarcinoma A549 xenografts in nude mice. The 40 A549 xenograft nude mice models were randomly divided into 4 groups (each group with 10 nude mice). Single radiotherapy group (group 1) was given a single external irradiation (6MV-X ray, 10 Gy) and peritumoral subcutaneous injection of 0.2 ml normal saline every day for 7 days. Single RHES group (group 2) was given peritumoral subcutaneous injection of 0.2 ml RHES (0.75 mg/ml) for 7 days. Combination therapy group (group 3) was given radiotherapy as the same as group 1 and RHES as the same as group 2. Control group was given normal saline as the same as group 1. The tumor volume was smaller in group 3 than in control group from the 8th day after treatment (P<0.05) and tumor regression occurred from the second week after treatment in group 3. On the 15th day after treatment, the inhibitory rates of tumor volume were 69.65%, 92.64% and 116.4% in groups 2, 1 and 3, respectively; MVD number was lower in group 3 than in group 1 (P<0.05); there was no statistical significance in VEGF expression between group 2 and control group as well as between group 3 and group 1 (P>0.05). Apoptosis was marked in group 3. Radiotherapy combined with weekly RHES can significantly inhibit tumor growth and earlier induce tumor regression, which may be related to the improvement of tumor hypoxia and the inhibition of radiation-induced tumor angiogenesis. Short-term application (1 week) of RHES is beneficial to clinical practice.

Promoter methylation of p16, Runx3, DAPK and CHFR genes is frequent in gastric carcinoma.

AIMS AND BACKGROUND: Transcriptional silencing induced by hypermethylation of CpG islands in the promoter regions of genes is believed to be an important mechanism of carcinogenesis in human cancers including gastric cancer. A number of reports on methylation of various genes in gastric cancer have been published, but most of these studies focused on cancer tissues or only a single gene. In this study, we determined the promoter hypermethylation status and mRNA expression of 4 genes: p16, Runx3, DAPK and CHFR. METHODS: Methylation-specific polymerase chain reaction (MSP) was used to determine the methylation status of p16, Runx3, DAPK and CHFR gene promoters in cancer and adjacent normal gastric mucosa specimens from 70 patients with gastric cancer, as well as normal gastric biopsy samples from 30 people without cancer serving as controls. In addition, the mRNA expression of p16, Runx3, DAPK and CHFR was investigated in 34 gastric cancer patients by RT-PCR. Bisulfite DNA sequence analysis was applied to check the positive samples detected by MSP. RESULTS: When carcinoma specimens were compared with adjacent normal gastric mucosa samples, a significant increase in promoter methylation of p16, Runx3, DAPK and CHFR was observed, while all 30 histologically normal gastric specimens were methylation free for all 4 genes. The methylation rate of the 4 genes increased from normal stomach tissue to tumor-adjacent gastric mucosa to gastric cancer tissue. Concurrent methylation in 2 or more genes was found in 22.9% of tumor-adjacent normal gastric mucosa and 75.7% of cancer tissues. No correlation was found between hypermethylation and other clinicopathological parameters such as sex, age, and tumor location. However, the frequency of DAPK and CHFR methylation in cancer tissues was significantly associated with the extent of differentiation and lymph node metastasis (P < 0.05) and the frequency of Runx3 methylation was significantly associated with tumor size (P < 0.05). Weak expression and loss of expression of the 4 genes was observed in cancer tissues and was significantly associated with promoter hypermethylation (P < 0.05). CONCLUSIONS: Promoter hypermethylation of p16, Runx3, DAPK and CHFR is frequent in gastric cancer. DAPK and CHFR promoter hypermethylation may be an important help in evaluating the differentiation grade and lymph node status of gastric cancer. Weak gene expression and loss of gene expression due to promoter hypermethylation may be a cancer-specific event.

Reduction of recruitment of Acartia pacifica nauplii from benthic resting eggs due to organochlorine pesticides.

Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The potential effects of two organochlorine pesticides, hexchloriobinzene (HCH) and dichlorodiphenyltrichloroethane (DDT), on the recruitment of Acartia pacifica nauplii from benthic resting eggs in the seabed of Xiamen Bay were experimentally investigated. The abundance of A. pacifica nauplii hatched from the sediment significantly decreased with the increase of pesticide concentration. Trimmed Spearman-Karber analysis gave sediment 96-h LC50 values were 84.81 ng/g for HCH, and 157.94 ng/g for DDT. The median AI (AI50) was -0.77, which suggested that the combined effect of HCH and DDT showed a weak effect than individual effects. There was a positive relationship between mortality and exposure time in DDT treatment, while the relationship was not significant in HCH treatment. The results suggest that organochlorine pesticides can reduce recruitment of A. pacifica nauplii from benthic resting eggs to planktonic population.