[Hepatocellular Carcinoma-Derived Exosomes: Key Players in Intercellular Communication Within the Tumor Microenvironment]. / 肝癌外泌体在肿瘤微环境细胞间通讯中的作用.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths in the world. Due to the insidious onset and rapid progression and a lack of effective treatments, the prognosis of patients with HCC is extremely poor, with the average 5-year survival rate being less than 10%. The tumor microenvironment (TME), the internal environment in which HCC develops, can regulate the oncogenesis, development, invasion, and metastasis of HCC. During the process of cancer progression, HCC cells can regulate the biological behaviors of tumor cells, cancer-associated fibroblasts, cancer-associated immune cells, and other cells in the TME by releasing exosomes containing specific signals, thereby promoting cancer progression. However, the exact molecular mechanisms and the roles of exosomes in the specific cellular regulation of these processes are not fully understood. Herein, we summarized the TME components of HCC, the sources and the biological traits of exosomes in the TME, and the impact of mechanical factors on exosomes. In addition, special attention was given to the discussion of the effects of HCC-exosomes on different types of cells in the microenvironment. There are still many difficulties to be overcome before exosomes can be applied as carriers in clinical cancer treatment. First of all, the homogeneity of exosomes is difficult to ensure. Secondly, exosomes are mainly administered through subcutaneous injection. Although this method is simple and easy to implement, the absorption efficiency is not ideal. Thirdly, exosome extraction methods are limited in number and inefficient, making it difficult to prepare exosomes in large quantities. It is important to ensure that exosomes are used in sufficient quantities to trigger an effective tumor immune response, especially for exosome-mediated tumor immunotherapy. With the improvement in identification, isolation, and purification technology, exosomes are expected to be successfully used in the clinical diagnosis of early-stage HCC and the clinical treatment of liver cancer.

Autophagy modulates FSS-induced epithelial-mesenchymal transition in hepatocellular carcinoma cells.

Hepatocellular carcinoma is a highly fatal disease and threatens human health seriously. Fluid shear stress (FSS), which is caused by the leakage of plasma from abnormally permeable tumor blood vessels and insufficient lymphatic drainage, has been identified as contributing pathologically to cancer metastasis. Autophagy and epithelial-mesenchymal transition (EMT) are both reported to be involved in cancer cell migration and invasion, but little has been revealed about the interaction between autophagy and EMT under a tumor mechanical microenvironment. Here, we identified that exposure to 1.4 dyne/cm2 FSS could promote the formation of autophagosomes and significantly increase the expressions of autophagy-related markers of beclin1 and ATG7, and the ratio of LC3Ⅱ/Ⅰ in both of HepG2 and QGY-7703 cells. The FSS loading also elevated the levels of mesenchymal markers N-cadherin, Vimentin, Twist, Snail, and ß-catenin, while the epithelial markers E-cadherin showed a decrease. Once the autophagy was blocked by 3-methyladenine (3-MA) or knocking ATG5 down, the occurrence of FSS-induced EMT was inhibited dramatically according to the expression and translocation of E-cadherin, N-cadherin, and ß-catenin. Given the effect of EMT on cell migration, we observed that inhibition of autophagy could impede FSS-induced cell migration. Collectively, this study demonstrated that autophagy played a crucial role in FSS-induced EMT and cell migration in hepatocellular carcinoma.

L-arginine Attenuates Hypobaric Hypoxia-Induced Increase in Ornithine Decarboxylase 1.

BACKGROUND: Chronic hypoxia-induced pulmonary hypertension and vascular remodeling have been shown to be associated with ornithine decarboxylase 1 (ODC1). However, few animal studies have investigated the role of ODC1 in acute hypoxia. OBJECTIVES: We investigated ODC1 gene expression, morphologic and functional changes, and the effect of L-arginine as an attenuator in lung tissues of rats exposed to acute hypobaric hypoxia at a simulated altitude of 6000 m. METHODS: Sprague-Dawley rats exposed to simulated hypobaric hypoxia (6000 m) for 24, 48, or 72 hours were treated with L-arginine (L-arginine group, 20 mg/100 g intraperitoneal; n=15) or untreated (non-L-arginine group, n=15). Control rats (n=5) were maintained at 2260 m in a normal environment for the same amount of time but were treated without L-arginine. The mean pulmonary artery pressure was measured by PowerLab system. The morphologic and immunohistochemical changes in lung tissue were observed under a microscope. The mRNA and protein levels of ODC1 were measured by real-time polymerase chain reaction and Western-blot, respectively. RESULTS: Hypobaric hypoxia induced pulmonary interstitial hyperemia and capillary expansion in the lungs of rats exposed to acute hypoxia at 6000 m. The mean pulmonary artery pressure and the mRNA and protein levels of ODC1 were significantly increased, which could be attenuated by treatment with L-arginine. CONCLUSIONS: L-arginine attenuates acute hypobaric hypoxia-induced increase in mean pulmonary artery pressure and ODC1 gene expression in lung tissues of rats. ODC1 gene contributes to the development of hypoxic pulmonary hypertension.

[Effects of silencing Snail1 gene on the expression of tight junction proteins and the migration ability of Hep-2 cells].

To investigate the effects of Snail1 gene silence on the expression of tight junction proteins and the migration ability of Hep-2 cells, Hep-2 cells were transfected with plasmids which is containing the shRNA of Snail1 gene, and cultured till the cells could be passaged stably (named Sh-snail1 cells). The expression of tight junction proteins (ZO-1, Occludin, Claudin-5) were detected by Western blot. The migration ability of Sh-snail1 cells was investigated by wound healing assay, and the protein expression of members of RhoGTPase family (RhoA, Cdc42) was detected by Western blot, which is closely related to the migration ability. Our results showed that the expression of tight junction proteins (ZO-1, Occludin, Claudin-5) was significantly increased; the migration ability of Sh-snail1 cell was inhibited; the expression of RhoA and Cdc42 was downregulated. All of these indicated that silencing the gene of Snail1 in Hep-2 cells can up-regulate the expression of tight junction proteins and down regulate the expression of Cdc42 and RhoA, and further inhibit the migration of Hep-2 cells. Furthermore, opening of the tight junctions between cells and the stronger migration ability of cancer cells are important processes in cancer metastasis. It is confirmed that the Snail1 gene is closely related to the two processes, providing an experimental basis for targeted therapy of laryngeal squamous cell carcinoma.

Two new compounds from the leaves of Indocalamus latifolius.

Two new compounds, erythro-syringylglycerol-9-O-trans-4-hydroxycinnamate 7-O-ß-d-glucopyranoside (1) and indocalatin A (2), together with three known ones, 5,7,3'-trihydroxy-6-C-ß-d-digitoxopyranosyl-4'-O-ß-d-glucopyranosyl flavonoid (3), 5,4'-dihydroxy-3',5'-dimethoxy-7-O-[ß-d-apiose-(1→2)]-ß-d-glucopyranosyl flavonoid (4), and tricin-6-C-ß-boivinopyranosyl-8-C-ß-glucopyranoside (5), were isolated from the 95% EtOH extract of Indocalamus latifolius leaves. Their molecular structures were determined by UV, IR, HRESIMS, CD, and 1D and 2D NMR data analyses.

Adsorption-desorption characteristics of methyl ethyl ketone with modified activated carbon and inhibition of 2,3-butanediol production.

UNLABELLED: Activated carbon (AC) is seldom applied for recovering ketone-based volatile organic compounds because of safety concerns. Adsorption of methyl ethyl ketone (MEK) with AC is a highly exothermic reaction that potentially causes fires in AC beds. Moreover, 2,3-butanediol (BDO) is produced in the desorbed solvent, causing yellowing and odor of the recovered solvent. This study applied a continuous adsorption-desorption apparatus for evaluating the operating capacities and BDO concentration in recovered MEK containing modified and original ACs. AC-1 (TAKETA- G2X) was used as the target for modification. The experimental results indicate that using MgO as the modifier increases the ignition point by 12°C and that applying KNO3 as the modifier reduces the AC ignition point by 28°C (compared with AC-1). The BDO concentration of the desorbed MEK solvent can be reduced by increasing the loading of the modifying agent (Ethanolamine) (Im-1: 3.1 wt%; Im-5: 6.2 wt%). Moreover, applying the AC pretreated with nitrogen (Im-6) as adsorbent significantly reduces the BDO concentration (from 0.123 wt% to 0.073 wt%). Because desorption and purging procedures were performed in N2 atmospheres, the BDO concentrations of the desorbed MEK solvents were relatively low and ranged from 0.032 wt% to 0.043 wt%. When the MEK concentration was reduced to 2000 ppm, lower BDO concentrations (0.012-0.022 wt%) were measured in the recovered MEK solvent. The way to modify activated carbon and a better desorbing sequence to effectively inhibit the oxidation of MEK to BDO are developed. The results obtained indicate that the BDO concentration in the desorbed solvent was lower than the original MEK solvent (0.023 wt%). Different approaches can be applied simultaneously to achieve high inhibition effects; however, carbon adsorption performance may be negatively affected. IMPLICATIONS: The study is motivated to improve the quality of recovered solvent and reduce fire hazards, particularly when AC is applied for adsorbing a ketone-based solvent (e.g., MEK). The experimental results indicate that the BDO concentration in the recovered solvent can be reduced and the ignition point of AC can be increased by modifying the AC with an appropriate agent.

High altitude genetic adaptation in Tibetans: no role of increased hemoglobin-oxygen affinity.

High altitude exerts selective evolutionary pressure primarily due to its hypoxic environment, resulting in multiple adaptive responses. High hemoglobin-oxygen affinity is postulated to be one such adaptive change, which has been reported in Sherpas of the Himalayas. Tibetans have lived on the Qinghai-Tibetan plateau for thousands of years and have developed unique phenotypes, such as protection from polycythemia which has been linked to PDH2 mutation, resulting in the downregulation of the HIF pathway. In order to see if Tibetans also developed high hemoglobin-oxygen affinity as a part of their genetic adaptation, we conducted this study assessing hemoglobin-oxygen affinity and their fetal hemoglobin levels in Tibetan subjects from 3 different altitudes. We found normal hemoglobin-oxygen affinity in all subjects, fetal hemoglobin levels were normal in all except one and no hemoglobin variants in any of the subjects. We conclude that increased hemoglobin-oxygen affinity or increased fetal hemoglobin are not adaptive phenotypes of the Tibetan highlanders.

Unveiling the Impact of Hemodynamics on Endothelial Inflammation-Mediated Hepatocellular Carcinoma Metastasis Using a Biomimetic Vascular Flow Model.

Hepatocellular carcinoma (HCC) hematogenous dissemination is a leading cause of HCC-related deaths. The inflammatory facilitates this process by promoting the adhesion and invasion of tumor cells in the circulatory system. But the contribution of hemodynamics to this process remains poorly understood due to the lack of a suitable vascular flow model for investigation. This study develops a vascular flow model to examine the impact of hemodynamics on endothelial inflammation-mediated HCC metastasis. This work finds the increasing shear stress will reduce the recruitment of HCC cells by disturbing adhesion forces between endothelium and HCC cells. However, this reduction will be restored by the inflammation. When applying high FSS (4-6 dyn cm-2) to the inflammatory endothelium, there will be a 4.8-fold increase in HCC cell adhesions compared to normal condition. Nevertheless, the increase fold of cell adhesions is inapparent, around 1.5-fold, with low and medium FSS. This effect can be attributed to the FSS-induced upregulation of ICAM-1 and VCAM-1 of the inflammatory endothelium, which serve to strengthen cell binding forces. These findings indicate that hemodynamics plays a key role in HCC metastasis during endothelial inflammation by regulating the expression of adhesion-related factors.

Isolation and identification of three new phenylpropanoids from the culms of phyllostachys nigra var. henonis (mitford) Rendle.

Three new phenylpropanoids, namely (7'R,8'R) guaiacylglycerol 4'-O-ß-D-[6″-O-(4-O-ß-D-glucopyranosyl)-p-hydroxyl-benzoyl]-glucopyranoside (1), (7 R,8R) guaiacylglycerol 8-O-1'-(2',6'-dimethoxy-4'-O-ß-D-glucopyranosyl)-benzene (2), (7'R,8'R) guaiacylglycerol 4'-O-ß-D-[6″-O-3,5-dimethoxy-4-hydroxylbenzoyl]-gluco-pyranoside (3), along with one known phenylpropanoid (4) were isolated from the ethanol extract of Phyllostachys nigra var. henonis fresh culm. The structures of all compounds were determined by analysis of UV, 1D NMR, 2D NMR, HR-ESI-MS and CD data. All compounds were evaluated for their DPPH radical scavenging activity. Compound 2 (IC50 54.9 µM) and 3 (IC50 77.2 µM) exhibited moderate antioxidant activity compared with two positive control compounds L-ascorbic acid (IC50 15.5 µM) and 2,6-ditertbutyl-4-methyl phenol (IC50 19.1 µM).

A convenient research strategy for functional verification of epigenetic regulators during spermatogenesis.

Spermatogenesis is a fundamental process that requires a tightly controlled epigenetic event in spermatogonial stem cells (SSCs). The mechanisms underlying the transition from SSCs to sperm are largely unknown. Most studies utilize gene knockout mice to explain the mechanisms. However, the production of genetically engineered mice is costly and time-consuming. In this study, we presented a convenient research strategy using an RNA interference (RNAi) and testicular transplantation approach. Histone H3 lysine 9 (H3K9) methylation was dynamically regulated during spermatogenesis. As Jumonji domain-containing protein 1A (JMJD1A) and Jumonji domain-containing protein 2C (JMJD2C) demethylases catalyze histone H3 lysine 9 dimethylation (H3K9me2), we firstly analyzed the expression profile of the two demethylases and then investigated their function. Using the convenient research strategy, we showed that normal spermatogenesis is disrupted due to the downregulated expression of both demethylases. These results suggest that this strategy might be a simple and alternative approach for analyzing spermatogenesis relative to the gene knockout mice strategy.

Physiological profile of elite Chinese female wrestlers.

The purpose of this investigation was to describe the physiological profile of elite, senior Chinese female wrestlers. Twenty-five elite wrestlers, nationally ranked in the top 3 of their weight class, participated in this study. The subjects included Olympic and world champion medalists. The physiological profile included testing of running maximal oxygen consumption (VO2max), 3,200-m run time, 400-m run time, 30-second Wingate anaerobic power and capacity, shoulder, elbow, knee, and trunk isokinetic torque, and 1 repetition maximums (1RMs) in specified exercises. The major results (mean ± SD) were VO2max: 50.58 ± 3.33 ml·kg(-1)·min(-1); 3,200-m run: 14 minutes 1 second ± 49 seconds; 400-m run: 1 minute 11 seconds ± 4 seconds; Wingate maximal anaerobic power: 495.21 ± 79.13 W and mean power: 262.97 ± 52.39 W; 1RM deadlift: 124 ± 19 kg; 1RM deep squat: 98 ± 11 kg; 1RM prone rowing: 72 ± 8 kg; 1RM power clean: 76 ± 12 kg; and 1RM hold and squat: 109 ± 17 kg. In absolute terms in the majority of measures, the heavier weight classes had greater values than the lighter weight classes, but relative to body mass, there were few differences in measures between the weight classes. The Olympic and World Championship medalist had the best value or was at the upper end of a measure's range for the strength and power measures. The results indicate that female wrestling success is not dependent on one physiological characteristic, but that a variety of physiological profiles can result in success. These data on elite female wrestlers can be compared with other wrestlers to help determine individual weaknesses or strengths and to design training programs that result in wrestling success.

Cathepsin K contributed to disturbed flow-induced atherosclerosis is dependent on integrin-actin cytoskeleton-NF-κB pathway.

Atherosclerosis is a chronic inflammatory disease, occurring preferentially in bifurcation, branching, and bending of blood vessels exposed to disturbed flow. Disturbed flow in atheroprone areas activates elevated proteases, degrading elastin lamellae and collagenous matrix, resulting in endothelial dysfunction and vascular remodeling. As a mediator for extracellular matrix protein degradation, cathepsin K (CTSK) was directly regulated by hemodynamics and contributed to atherosclerosis. The mechanism of CTSK responding to disturbed flow and contributing to disturbed flow-induced atherosclerosis is unclear. In this study, the partial carotid ligation model of mice and in vitro disturbed shear stress model were constructed to explore the contribution and potential mechanism of CTSK in atherosclerosis. Our results indicated that CTSK elevated in the disturbed flow area in vivo and in vitro along with endothelial inflammation and atherogenesis. Additionally, the expression of integrin αvß3 was upregulated in these atheroprone areas. We found that inhibition of the integrin αvß3-cytoskeleton pathway could significantly block the activation of NF-κB and the expression of CTSK. Collectively, our findings unraveled that disturbed flow induces increased CTSK expression, and contributes to endothelial inflammation and vascular remodeling, leading to atherogenesis eventually. This study is helpful to provide new enlightenment for the therapy of atherosclerosis.

An oncogenic tyrosine kinase inhibits DNA repair and DNA-damage-induced Bcl-xL deamidation in T cell transformation.

A transgenic mouse model of T cell lymphoma was used to investigate the transforming events mediated by an oncogenic tyrosine kinase in pretumorigenic CD4-CD8- (DN) thymocytes. Parental CD45(-/-) and p56(lck-F505Y) mice do not develop tumors, whereas their CD45(-/-)p56(lck-F505Y) progeny develop T lymphomas. Increased but nononcogenic p56lck kinase activity in p56(lck-F505Y) mice DN thymocytes causes cell-cycle progression, survival, and Bcl-XL upregulation. Additional unique oncogenic signals occur in pretumorigenic CD45(-/-)p56(lck-F505Y) thymocytes in which p56lck kinase activity is 2- to 3-fold higher relative to p56(lck-F505Y): inhibition of DNA repair, inhibition of DNA-damage-induced Bcl-XL deamidation, Bax conformational change and mitochondrial translocation, cytochrome c release, and the apoptotic caspase execution cascade. Inhibition of Bcl-XL deamidation may be a critical switch in oncogenic kinase-induced T cell transformation.

Fluid Shear Stress-Induced Exosomes from Liver Cancer Cells Promote Activation of Cancer-Associated Fibroblasts via IGF2-PI3K Axis.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are of considerable importance in tumor progression by interacting with the tumor microenvironment. However, the hidden mechanism explaining how tumor cells interact with CAFs in the tumor mechanical microenvironment remains largely unknown. METHODS: We highlighted exosomes as the mediator modulating the interaction between liver cancer cells and CAFs under mechanical conditions. The normal hepatic stellate cells LX2 were exposed to the medium or exosomes from the HepG2 cells with or without fluid shear stress subjection, and the CAFs activation markers were checked. To further explore the potential role of PI3K, which is active in liver fibrosis, the PI3K inhibitor was used. RESULTS: The specific markers of CAFs, FAP, and α-SMA, increased in LX2 with subjection to the fluid shear stress-induced exosomes from HepG2 cells. In turn, the enriched IGF2 in the exosomes activated the IGF2-PI3K signaling pathway in LX2 cells. CONCLUSIONS: These findings reveal that fluid shear stress-induced liver cancer cells possess a stronger capacity to convert normal fibroblasts to CAFs than statically cultured liver cancer cells, and tumor-derived exosomes mediated the intercellular cross-talk between liver cancer cells and fibroblasts.

Matrix Vesicles as a Therapeutic Target for Vascular Calcification.

Vascular calcification (VC) is linked to an increased risk of heart disease, stroke, and atherosclerotic plaque rupture. It is a cell-active process regulated by vascular cells rather than pure passive calcium (Ca) deposition. In recent years, extracellular vesicles (EVs) have attracted extensive attention because of their essential role in the process of VC. Matrix vesicles (MVs), one type of EVs, are especially critical in extracellular matrix mineralization and the early stages of the development of VC. Vascular smooth muscle cells (VSMCs) have the potential to undergo phenotypic transformation and to serve as a nucleation site for hydroxyapatite crystals upon extracellular stimulation. However, it is not clear what underlying mechanism that MVs drive the VSMCs phenotype switching and to result in calcification. This article aims to review the detailed role of MVs in the progression of VC and compare the difference with other major drivers of calcification, including aging, uremia, mechanical stress, oxidative stress, and inflammation. We will also bring attention to the novel findings in the isolation and characterization of MVs, and the therapeutic application of MVs in VC.

Effective disinfecting of protective devices used in the course of treating SARS-CoV2-positive patients.

BACKGROUND: Powered Air-Purifying Respirator (PAPR) was widely used in Sengkang General Hospital (SKH) during the SARS-CoV-2 outbreak. Ensuring a sustained supply of clean and reusable PAPR masks for frontline medical team is an immediate challenge. The Central Sterile Supplies Unit (CSSU) adopts existing disinfection methods and technology for the reprocessing of reusable personal protective equipment (PPE) such as PAPR masks and goggles. OBJECTIVE: To determine an effective disinfecting method for protective devices used in the course of treating SARS-CoV2-positive patients. METHOD: A comparison on surface disinfection and modified thermal disinfection outcome was conducted on 30 PAPR masks through detecting the presence of adenosine triphosphate (ATP) by swab following both disinfecting methods. RESULTS: The modified thermal cycles emerged as the recommended disinfection method. DISCUSSION: The outcome of this study has enhanced understanding on the risk imposed on frontline healthcare personnel who perform surface disinfecting on masks for reuse during the work shift. Leveraging on the current expertise from existing instrument logistics, CSSU takes charge of the processing and stock management of SKH's PAPR masks. An additional workflow is needed to establish reprocessing methods for other reusable PPEs such as face shields or overalls.

Generation of a live attenuated influenza A vaccine by proteolysis targeting.

The usefulness of live attenuated virus vaccines has been limited by suboptimal immunogenicity, safety concerns or cumbersome manufacturing processes and techniques. Here we describe the generation of a live attenuated influenza A virus vaccine using proteolysis-targeting chimeric (PROTAC) technology to degrade viral proteins via the endogenous ubiquitin-proteasome system of host cells. We engineered the genome of influenza A viruses in stable cell lines engineered for virus production to introduce a conditionally removable proteasome-targeting domain, generating fully infective PROTAC viruses that were live attenuated by the host protein degradation machinery upon infection. In mouse and ferret models, PROTAC viruses were highly attenuated and able to elicit robust and broad humoral, mucosal and cellular immunity against homologous and heterologous virus challenges. PROTAC-mediated attenuation of viruses may be broadly applicable for generating live attenuated vaccines.

Comparison of reduced intensity and myeloablative conditioning regimens for stem cell transplantation in patients with malignancies: a meta-analysis.

OBJECTIVE: The reduced intensity conditioning (RIC) stem cell transplantation is widely employed for the treatment of many hematologic malignancies, but the survival effectiveness is still unclear. This study conducted an updated meta-analysis to determine whether any significant difference could be found by using RIC vs. myeloablative conditioning (MAC) regimen for transplantation in patients with malignancies. METHODS: We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and relevant articles (1987.01-2009.12). Comparative studies were carried out on clinical therapeutic effect of RIC and MAC on the survival outcomes and the transplantation-related complications. RESULTS: We obtained 1776 records, and 29 studies totaling 6235 patients have been assessed. Compared with MAC regimen, the RIC regimen had a higher overall survival (OS) at one-yr and no difference at two-yr later after transplantation. RIC regimen had significantly lower rates of disease-free survival (DFS) after two-yr follow-up, lower incidences of ≥ II degree acute graft-versus-host disease (aGVHD), and lower TRM [OR, 0.61, 95% CI (0.53, 0.69)], but with a higher relapse rate [OR, 1.88(1.41, 2.51)]. No significant difference was found in rates of cytomegalovirus (CMV) infection and chronic GVHD between the regimens. CONCLUSIONS: This meta-analysis confirmed that compared with MAC condition regimen, the RIC regimen had a consistently equivalent or even better rate in OS, but with lower DFS at longer follow-up.

Proto-oncogene c-erbB2 initiates rat primordial follicle growth via PKC and MAPK pathways.

BACKGROUND: c-erbB2, a proto-oncogene coding epidermal growth factor receptor-like receptor, also as a chemosensitivity/prognosis marker for gynecologic cancer, may be involved in initiation of growth of rat primordial follicles. The aim of the present study is to investigate the role and signal pathway of c-erbB2 in onset of rat primordial follicle development. METHODS: The expression of c-erbB2 mRNA and protein in neonatal ovaries cultured 4 and 8 days with/without epidermal growth factor (EGF) were examined by in situ hybridization, RT-PCR and western blot. The function of c-erbB2 in the primordial folliculogenesis was abolished by small interfering RNA transfection. Furthermore, MAPK inhibitor PD98059 and PKC inhibitor calphostin were used to explore the possible signaling pathway of c-erbB2 in primordial folliculogenesis. RESULTS: The results showed that c-erbB2 mRNA was expressed in ooplasm and the expression of c-erbB2 decreased after transfection with c-erbB2 siRNA. Treatment with EGF at 50 ng/ml significantly increased c-erbB2 expression and primary and secondary follicle formation in ovaries. However, this augmenting effect was remarkably inhibited by c-erbB2 siRNA transfection. Furthermore, folliculogenesis offset was blocked by calphostin (5 x 10(-4) mmol/L) and PD98059 (5 x 10(-2) mmol/L), but both did not down-regulate c-erbB2 expression. In contrast, the expressions of p-ERK and p-PKC were decreased obviously by c-erbB2 siRNA transfection. CONCLUSIONS: c-erbB2 initiates rat primordial follicle growth via PKC and MAPK pathways, suggesting an important role of c-erbB2 in rat primordial follicle initiation and development.

A multiresidue method for 20 pesticides in Radix paeoniae Alba of Chinese herb by gas chromatography with electron-capture detection.

A rapid multiresidue method was developed for the determination of 20 pesticides in Radix paeoniae Alba of Chinese herb by ultrasonic wave extraction, silica gel column chromatography and gas chromatography (GC) with electron-capture detection (ECD) in this study, Mean recoveries of the method ranged from 74.45 to 115.14%. The validation of the proposed approach was verified on Isatis indigotica Fort, Pltycodon grandiflorum, Cotex mouta and Poria cocos of Chinese herbs; good recoveries were also obtained in the range of 72.51-113.47%, respectively.