Tuning Dzyaloshinskii-Moriya interaction via an electric field at the Co/h-BN interface.

The Dzyaloshinsky-Moriya interaction (DMI) at the Co/h-BN interface can emerge and be enhanced by applying a downward electric field. The height of the Co atom relative to the h-BN layer with the electric field determines the variation of DMI. One half reduction of J1 is beneficial to generate skyrmions. Tuning the DMI by an electric field sheds new light for research on skyrmions.

[The changes of processing method and theoretical pharmacodynamic analysis of largehead atractylodes rhizome].

Largehead atractylodes rhizome, known as "the first essential medicine for invigorating qi and strengthening spleen" , is one of the most commonly used Chinese materia medica. According to the different clinical treatment requirements, largehead atractylodes rhizome can be processed into a variety types of products, such as raw, fried with earth, stir-frying with bran, and deep-fried largehead atractylodes rhizome. The processing quality is of great significance to ensure the efficacy, drug safety and improve the preparation process. Through the detailed research on the processing methods of largehead atractylodes rhizome in ancient books, modern documents and norms, this study clarifies the history and evolution of the processing technology of largehead atractylodes rhizome in ancient and modern times, and summarizes the internal laws and external factors of the processing technology changes by combining the processing technology differences, materials addition and theoretical analysis of pharmacodynamics. It not only saves the tedious and repeated steps, but also improves and optimizes the efficacy and quality of the preparation, and gets standardization and unification in the follow-up practice, which provides a reference for the research and development of the processing technology of largehead atractylodes rhizome and other Chinese materia medica.

[Evidential research on the literature quoted in Compendium of Medicine].

One of the characteristics of Yixue Gangmu(, Compendium of Medicine) is collecting a large number of medical literatures before Ming Dynasty. And it quoted not only from medical books, but also other literature, with a time span from Han to Yuan Dynasty. From frequency of citation, we found that Lou Ying, the writer's ideas had more resonance with Zhu Danxi and Yi Shui School from academic point of view.

Simulation and Sensitivity Analysis of Microtubule-Based Biomechanical Mass Detector.

The microtubule is biologically the most rigid filament that is so critical to the cytoskeleton system. It is significant to study the mass sensitivity of microtubule in order to understand biophysical behaviors, such as the influence of kinesin and dynein moving along microtubules. In this research, the sensitivity of mass detector using individual microtubule is first studied. The frequency shifting of the detector due to mass loads is simulated. The influences of mass load positions and boundary conditions on the mass sensitivity are evaluated. It is predicted in this research that the mass sensitivity of a 1 µm microtubules-based mass detector could reach 10-17 g. Results also show that the resonant frequency decreases logarithmic linearly with the increase of the attached mass regardless of the microtubule length and the position of mass load. Moreover, the sensitivity of resonant frequency shift to the microtubule length is also analyzed.

[The MRI analysis of 220 cases of placenta previa complicated with placenta accrete or not].

Objective: To investigate the diagnostic value of MRI for placenta previa complicated with placenta accreta or not. Methods: A total of 220 placenta previa patients were diagnosed by prenatal ultrasound and MRI in The Second Affiliated Hospital of Wenzhou Medical University from May 2014 to May 2017.The MRI images of 220 placenta previa patients suspicious of placenta previa were interpreted by two radiologists who majored on gynecological radiology. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of two radiologists in diagnosis of placenta accreta were calculated respectively. Kappa test were used to verify the consistency between two doctors, as well as their MRI diagnosis and pathological results. The diagnostic value of MRI and pathological were assessed by Chi-square test and receiver operating characteristic (ROC)curve. Results: The 220 patients were all confirmed with placenta previa by surgical pathology.Out of 220, 71 cases were diagnosed as placenta accreta, and 149 cases were diagnosed without placenta accreta. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value with physician A and physician B were 90.1%/84.5%, 88.6%/89.9%, 89.1%/88.2%, 79.0%/80.0% and 95.0%/92.4%, respectively.The consistency between MRI diagnosis and pathological results was excellent in physician A (κ=0.759), and good in physician B (κ=0.734). However, the sensitivity, specificity and accuracy of diagnosis between two physicians had no significant difference (all P>0.05). The area under the curve (AUC) of ROC in physician A and B were 0.858 and 0.847 (P=0.980). Conclusion: MRI is feasible for patients with placenta previa, as the sensitivity, specificity and accuracy of MRI are high in assessing whether placenta previa complicated with placenta accreta or not.

Gene expression profiles of the heterotrophic microalga Chlorella pyrenoidosa F-9.

A strain of the microalga Chlorella pyrenoidosa F-9 in our laboratory showed special characteristics when transferred from autotrophic to heterotrophic culture. In order to elucidate the possible metabolic mechanism, the gene expression profiles of the autonomous organelles in the green alga C. pyrenoidosa under autotrophic and heterotrophic cultivation were compared by suppression subtractive hybridization technology. Two subtracted libraries of autotrophic and heterotrophic C. pyrenoidosa F-9 were constructed, and 160 clones from the heterotrophic library were randomly selected for DNA sequencing. Dot blot hybridization showed that the ratio of positivity was 70.31% from the 768 clones. Five chloroplast genes (ftsH, psbB, rbcL, atpB, and infA) and two mitochondrial genes (cox2 and nad6) were selected to verify their expression levels by real-time quantitative polymerase chain reaction. Results showed that the seven genes were abundantly expressed in the heterotrophic culture. Among the seven genes, the least increment of gene expression was ftsH, which was expressed 1.31-1.85-fold higher under heterotrophy culture than under autotrophy culture, and the highest increment was psbB, which increased 28.07-39.36 times compared with that under autotrophy conditions. The expression levels of the other five genes were about 10 times higher in heterotrophic algae than in autotrophic algae. In inclusion, the chloroplast and mitochondrial genes in C. pyrenoidosa F-9 might be actively involved in heterotrophic metabolism.

Etorphine inhibits cell growth and induces apoptosis in SK-N-SH cells: involvement of pertussis toxin-sensitive G proteins.

Opiates have been used extensively in the treatment of pain but with the severe side effect of addiction, which is believed to be related to opiates' direct (primary) or indirect (secondary) neurotoxicity. In this study, the effects of opioids on cell growth and apoptosis have been examined in human neuroblastoma cell line SK-N-SH. Etorphine, a wide-spectrum and potent agonist of opioid receptors, was found to significantly inhibit cell growth and to induce apoptosis. The inhibitory and apoptotic activities of etorphine followed a dose- and time-dependent manner. The more specific agonists of opioid receptors such as morphine, [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAGO), [D-Pen2, D-Pen5]-enkephalin (DPDPE), dynorphin A and nociceptin/orphanin FQ did not show similar toxic activities under the same conditions. In addition, the effects of etorphine could not be blocked by the opioid receptor antagonist naloxone, suggesting that the effects of etorphine might not be mediated by a classical opioid receptor. However, pretreatment of SK-N-SH cells with pertussis toxin (PTX) blocked the inhibition of cell growth and apoptosis induced by etorphine, indicating the involvement of PTX-sensitive G proteins in the processes. It was also shown that etorphine-induced apoptosis was prevented by actinomycin D (AD) and interleukin-1beta converting enzyme inhibitor I. Interestingly, etorphine was similarly potent to inhibit growth of pheochromocytoma (PC12) cells but less effective in SH-SY5Y neuroblastoma cells and C6 glioma cells. We propose that inhibition of cell growth and induction of apoptosis may be one mechanism of opioid neurotoxicity.

Endogenous opioid receptor-like receptor in human neuroblastoma SK-N-SH cells: activation of inhibitory G protein and homologous desensitization.

Endogenous expression of opioid receptor-like receptor (ORL1), in human neuroblastoma SK-N-SH cells was demonstrated by binding with nociceptin/ orphanin FQ (N/OFQ). Scatchard analysis of [3H]N/ OFQ saturation binding data gave Kd = 1.3 +/- 0.1 nM and Bmax = 1.58 +/- 2.5 fmol/mg protein. N/OFQ stimulation increased [35S]GTP gamma S binding to cell membranes and attenuated forskolin-induced cAMP accumulation in a concentration-dependent manner. The effects of N/OFQ were eliminated by the pretreatment of pertussis toxin (PTX) but not by the antagonists of opioid receptors, revealing mediation of N/OFQ signal transduction by ORL1 receptor and PTX sensitive G protein(s). The ability of N/OFQ to inhibit cAMP production was greatly reduced after prechallenging with N/OFQ, indicating that ORL1 undergoes homologous desensitization in neuronal cells.

Progesterone induces apoptosis and up-regulation of p53 expression in human ovarian carcinoma cell lines.

BACKGROUND: Progesterone (PROG) has been shown to reduce the risk of developing ovarian carcinoma in postmenopausal women who have undergone estrogen and progestogen replacement therapy, and it has been clinically used to treat some types of ovarian tumors. It is not yet clear whether or not the antitumor activity of progestogen is due to its ability to induce apoptosis in precarcinomatous and carcinomatous ovarian cells. The apoptosis-related genes p53, bcl-2, and c-myc have important roles in the regulation of programmed cell death, and thus may be involved in the process of the suspected PROG-induced apoptosis. METHODS: Antiproliferation effects of PROG on 3AO and AO ovarian carcinoma cells were determined by 3H-thymidine incorporation. Apoptosis of the PROG-treated cells was determined by DNA laddering analysis and was quantitated by both nuclear condensation and flow cytometry after cells were stained with propidium iodide. Cell cycle analysis was also performed by flow cytometry. The expression of p53, bcl-2, and c-myc after 72 hours of PROG treatment was detected by Northern blot analysis. RESULTS: In both 3AO and AO cell lines, cells proliferation was maximally inhibited by PROG after 72 hours of treatment at 10 microM concentration. Under the same conditions, more than 50% of PROG-treated cells had undergone apoptosis, whereas less than 3% of the cells were apoptotic in untreated cell cultures. After exposure to PROG for 72 hours, cells were arrested in the G1 phase of the cell cycle, and the levels of p53 mRNA were remarkably increased in both cell lines. No changes in expression of bcl-2 or c-myc were detected. CONCLUSIONS: PROG significantly inhibited cell proliferation and induced apoptosis in both of the ovarian carcinoma cell lines tested in this study. PROG treatment markedly up-regulated p53 expression in these cells, indicating involvement of p53 in PROG-induced apoptosis.

Activation of N-methyl-D-aspartate receptor attenuates acute responsiveness of delta-opioid receptors.

Coadministration of antagonists of N-methyl-D-aspartate (NMDA) receptor and opioids has been shown to prevent development of opiate tolerance in animal and clinical studies, but its cellular and molecular mechanisms are not understood. In this study, the effect of NMDA on delta-opioid receptor (DOR)-mediated signal transduction was investigated in neuroblastoma x glioma NG108-15 cells that functionally express both DOR and NMDA receptors. Acute incubation of NG108-15 cells with NMDA, a specific agonist of NMDA receptor, significantly attenuated the ability of DOR agonist [D-Pen2, D-Pen5]-enkephalin (DPDPE) to inhibit forskolin-stimulated cAMP production. The attenuation caused by NMDA was dose-dependent, and the EC50 of DPDPE increased 100-fold (from 4.6 nM to 500 nM) after NMDA treatment. The NMDA effect on responsiveness of delta-opioid receptors to DPDPE could be blocked by ketamine, a NMDA receptor-specific antagonist. This NMDA attenuation effect on DOR activity was also observed in neuronal primary cell cultures from fetal mouse brain but not in the Chinese hamster ovary cell line stably transfected with DOR alone. Interestingly, NMDA pretreatment reduced the cellular response to epinephrine but not to that of prostaglandin E1 in NG108-15 cells, which suggests differential modulation of NMDA on different G protein-coupled receptors. Pretreatment of NG108-15 cells with ketamine along with DPDPE greatly attenuated DPDPE-induced acute desensitization of DOR. Furthermore, the specific inhibitors of protein kinase C, either chelerythrine chloride or Go 6979, effectively blocked the NMDA effect, which indicates the involvement of protein kinase C in the process. In conclusion, the activation of NMDA receptors can attenuate acute responsiveness of DOR in neuronal cells, whereas its blockage leads to reduction of DOR desensitization. These results have thus provided an insight into cross-talk between NMDA and opioid signal transduction.

Functional expression, activation and desensitization of opioid receptor-like receptor ORL1 in neuroblastoma x glioma NG108-15 hybrid cells.

Neuroblastoma x glioma NG108-15 hybrid cells have been examined for the expression of opioid receptor-like receptor (ORL1). [3H]Nociceptin/orphanin FQ (OFQ) bound to the cell membrane specifically (Kd = 3.6 +/- 0.6 nM) and inhibited forskolin-stimulated cAMP accumulation (EC50 = 0.72 +/- 0.3 nM). The responsiveness of NG108-15 cells to nociceptin/OFQ was blocked by pertussis toxin but not by naltrindole. The inhibitory activity of nociceptin/OFQ was significantly reduced after a prechallenge with the same peptide but was not influenced by DPDPE pretreatment, indicating acute and homologous desensitization of ORL1 receptors. Naltrindole caused the overshoot of cAMP in DPDPE-pretreated cells but not in nociceptin/OFQ-pretreated cells. The results indicate that ORL1 is functionally expressed and does not cross-interact with specific ligands of the delta opioid receptor in NG108-15 cells.

[Platelet factor 4 acts as both inhibitor and protector of hematopoietic precursor cells: possible mechanism of action].

We have previously shown that platelet factor 4 (PF 4) is a potent inhibitor of megakaryocytopoiesis and that it may protect stem cells from 5-fluorouracil (5-FU) cytotoxicity. In the present work, the effects of human PF 4 on megakaryocyte (MK) growth from human CD34+ cord blood (CB) cells were studied in comparison with transforming growth factor beta 1 (TGF-beta 1). Development of MK from CD34+ cells in both plasma clot culture and liquid culture was significantly inhibited by PF 4 (5 micrograms/ml) and TGF beta 1 (1 ng/ml). Inhibition of cell growth by PF 4 was reversible judging from the fact that the CD34+ cells preincubated with PF 4 could regenerate colonies after washing and replating into the cultures. By contrast, TGF-beta 1 pretreated CD34+ cells gave rise to few colonies following replating. Moreover, incubation of CD34+ cells with PF 4 in liquid culture caused an increase in the number of both stem cell factor (SCF)-binding cells and CD34 antigen-bearing cells, and exhibited greater capacity to form MK colonies than control after the treatment of 5-FU. In vivo in mice, twice injections of PF 4 at 40 micrograms/kg with an interval of 6 h followed by one injection of 5-FU at 150 mg/kg resulted in a significant increase in the number of colony-forming cells with high proliferative potential (HPP-CFC) and colony-forming unit-megakaryocyte (CFU-MK) in bone marrow. In exponentially growing human erythroleukemia cells (HEL), the addition of PF 4 prolonged cell cycle progression and therefore resulted in an increased cell population in S phase, as determined by flow cytometric analysis. Different from PF 4, TGF-beta 1 blocked more cells in G 1 phase. These results demonstrate that PF 4 and TFG-beta 1 inhibit MK development from CD34+ CB cells by different mechanisms and suggest that PF 4, unlike TGF-beta 1, exerts its inhibitory effect on cell growth in a reversible and S phasespecific manner by which it protects stem cells and MK progenitor cells from 5-FU cytotoxicity.

[Effect of pigmented epithelium from different developmental stages of chick embryo on cell growth of retinal explants].

The model system to investigate the effect of retinal pigmented epithelium (PE) on the retinal development in vitro has been established in this laboratory. Chick retina separated from 5-day-old embryo (E 5) were cut into strips and explanted on the collagen substratum either in close contact with retinal PE (RPE), or without PE (R). The rates of cell proliferation of retinal strips cultured for 48 hr were measured by the uptake of radioactive thymidine and DNA contents. Both parameters in RPE were increased to values ranging from 137 to 167% when PE was taken from E5 and E6. However PE taken from E7, E8 and E9 had no effect on cell proliferation. The rate of cell proliferation of retina were increased both when separated retina and PE of E5 either from same or from an other eye closely contact again and when retina and PE of E5 were explanted together without separation. However the rates of cell proliferation were remained without much change when a millipore filter existed between retina and PE of E5 as well as the retina was inverted, the ganglion cell layer contacted with PE. The neurite outgrowth from retina explant with and without PE of E5 or E6 were also different. After culture for 24 hr the fiber length of neurite growing in RPE was only 36-39% of that in R. After 48 hr it was about 70% of that in R. This results suggested that the developmental stage of PE and the direct cell-to-cell contact of PE from E5 with photoreceptor layer of retina was important for the retinal cell proliferation. But PE had negative influence on neurite growth of retina in culture.

[Immuno-electron microscopical studies on the retinal basement membrane of chick embryo].

Retinal basement membrane (RBM), also called inner limiting membrane of retina, is constituted by extracellular matrix. It was reported that neurite outgrowth of a neuron was closely related to extracellular matrix, particularly the laminin. In this laboratory RBM was used as the optimal substrate for retinal cells in culture. We have studied the surface of RBM and its relation to neurite outgrowth by scanning electronmicroscopy and immunogold transmission electronmicroscopy. RBM could be separated by mechanical disruption of the retina mounted between 2 adhesive substrata (membrane filter and poly-L-lysine coated glass). The surface of RBM studied was the side of RBM facing the optic fiber layer and ganglion cell layer. Small particles densely distributed on surface of RBM (Plate I, Fig. 1 and 2) were shown to be chrysanthemum-like structures with radiative arms under the scanning electronmicroscopy (Plate I, Fig. 3 and 4). The radiative arms of RBM of 12-day old chick embryo (E 12) were more in number and longer in length than that of the 6-day old chick embryo (E 6). The axons of ganglion cell from E 6 retinal strip extended out very well on RBM (Plate I, Fig. 5). Growth cone was active with filopodia. The chrysanthemum-like structures changed to ball-particles when the RBM was cultured for 24 hr. Some of ball-particles lay over the growth cone, and some beside it. Over and beside the nerve fiber could also be seen some ball-particles. When many neurites grew on RBM, a lot of ball-particles were shown to be displaced and piled up (Plate I, Fig. 6). The whole amount RBM labeled by indirect immunogold staining of Müller glial cell could be observed by transmission electronmicroscopy. The gold particles wer located at the chrysanthemum-like structure of E 6 RBM (Plate II, Fig. 7) and E 12 RBM (Plate II, Fig. 8). It was suggested that those structures were the end foot of Müller glial cells. Staining of PBS control or mouse serum control was negative (Plate II, Fig. 9 and 10).(ABSTRACT TRUNCATED AT 250 WORDS)

The pigmented epithelium sustains cell growth and tissue differentiation of chicken retinal explants in vitro.

Embryonic retinae from 5-6-day-old chicks (E5-E6) were cut into stripes either in close contact with (RPE stripes) or in absence of the neighboring retinal pigmented epithelium (R stripes). The stripes were explanted and cultivated in vitro for up to 6 days, during which time they show the following differences in their characteristics of growth and differentiation. Compared with R stripes, RPE stripes morphologically showed a significant increase in size during the first 2 days in culture. Using E5 tissue, this is also demonstrated by a higher rate of cell proliferation (as measured by uptake of radioactive thymidine as well as by DNA contents). In contrast, R stripes after two days in culture show a much stronger neurite growth. After longer periods of culturing (5-6 days) we can show by cholinesterase histochemistry (AChE and BChE) and by PNA-lectin binding that the RPE stripes have started to form all major layers of the in vivo retina, whereas R stripes remain unstratified and start to degenerate earlier. We conclude that the pigment epithelium might exert a specific stimulus on growth and tissue differentiation of the neural retina not only during in vitro, but possibly also during in vivo development. The in vitro methods introduced here could become useful model systems to further investigate the significance of the RPE for developmental, regenerative and even adult processes of the neural retina. Their future applicability in ophthalmologic research is briefly discussed.