Lactate induces C2C12 myoblasts differentiation by mediating ROS/p38 MAPK signalling pathway

Lactate serves not merely as an energy substrate for skeletal muscle but also regulates myogenic differentiation, leading to an elevation of reactive oxygen species (ROS) levels. The present study was focused on exploring the effects of lactate and ROS/p38 MAPK in promoting C2C12 myoblasts differentiation. Our results demonstrated that lactate increased C2C12 myoblasts differentiation at a range of physiological concentrations, accompanied by enhanced ROS contents. We used n-acetylcysteine (NAC, a ROS scavenger) pretreatment and found that it delayed lactate-induced C2C12 myoblast differentiation by upregulating Myf5 expression on days 5 and 7 and lowering MyoD and MyoG expression. The finding implies that lactate accompanies ROS-dependent manner to promote C2C12 myoblast differentiation. Additionally, lactate significantly increased p38 MAPK phosphorylation to promote C2C12 cell differentiation, but pretreatment with SB203580 (p38 MAPK inhibitor) reduced lactate-induced C2C12 myoblasts differentiation. whereas lactate pretreatment with NAC inhibited p38 MAPK phosphorylation in C2C12 cells, demonstrating that lactate mediated ROS and regulated the p38 MAPK signalling pathway to promote C2C12 cell differentiation. In conclusion, our results suggest that the promotion of C2C12 myoblasts differentiation by lactate is dependent on ROS and the p38 MAPK signalling pathway. These observations reveal a beneficial role for lactate in increasing myogenesis through ROS-sensitive mechanisms as well as providing new ideas regarding the positive impact of ROS in improving the function of skeletal muscle.

A WeChat-based nursing intervention program improves the postoperative rehabilitation of breast cancer patients: results from a randomized controlled trial

Background

In postoperative setting, breast cancer (BC) patients can experience adverse effects, including fatigue, sleep disorders, and pain, which substantially affect their health-related quality of life (HRQoL). This study sought to assess the effectiveness of a WeChat-based multimodal nursing program (WCBMNP) that was specifically designed for the rehabilitation of women following BC surgery.

Methods

BC patients were randomly, single-blinded allocated to either the intervention (n=62) or control (n=63) cohorts. Over a period of 6 months (24 weeks), the intervention cohort received a WCBMNP in addition to routine nursing care, while the control cohort received routine nursing care only. To evaluate patients' fear of cancer recurrence (FCR), their overall fear score was assessed using the Japanese version of the Concerns About Recurrence Scale (CARS-J) for primary outcome. The initial outcome (HRQoL) and secondary results, such as fatigue, sleep, and pain, were examined using the Functional Assessment of Cancer Therapy-Breast (FACT-B, version 4.0) and Nursing Rating Scale (NRS), respectively.

Results

Two hundred and ten participants, 85 participants were excluded. Compared to the controls (n=63), the intervention cohort (n=62) showed statistically significant improvements in their CARS-J scores. The intervention cohort aggregate scores on the FACT-B improved significantly but were affected by the compounding influences of cohort dynamics, temporal progression, and their interaction. Similar improvements were observed in the social/family and functional well-being domains. Emotional well-being was improved based on the effects of time and group-time interaction. In the intervention cohort, the "BC-specific subscale for additional concerns" was affected by group and time, whereas physical well-being was only affected by time. Conversely, there were no statistically significant changes in the variables of fatigue, sleep, and pain.

Conclusions

The WCBMNP reduced FCR and significantly increased the HRQoL of female patients with BC postoperatively. The WCBMNP could be implemented as a postoperative rehabilitation intervention in this patient population to improve outcomes.

Trial Registration

Chinese Clinical Trial Registry (ChiCTR2400081557).

Lactate ameliorates palmitate-induced impairment of differentiative capacity in C2C12 cells through the activation of voltage-gated calcium channels

Palmitic acid (PA), a saturated fatty acid enriched in high-fat diet, has been implicated in the development of skeletal muscle regeneration dysfunction. This study aimed to examine the effects and mechanisms of lactate (Lac) treatment on PA-induced impairment of C2C12 cell differentiation capacity. Furthermore, the involvement of voltage-gated calcium channels in this context was examined. In this study, Lac could improve the PA-induced impairment of differentiative capacity in C2C12 cells by affecting Myf5, MyoD and MyoG. In addition, Lac increases the inward flow of Ca2+, and promotes the depolarization of the cell membrane potential, thereby activating voltage-gated calcium channels during C2C12 cell differentiation. The enchancement of Lac on myoblast differentiative capacity was abolished after the addition of efonidipine (voltage-gated calcium channel inhibitors). Therefore, voltage-gated calcium channels play an important role in improving PA-induced skeletal muscle regeneration disorders by exercising blood Lac. Our study showed that Lac could rescue the PA-induced impairment of differentiative capacity in C2C12 cells by affecting Myf5, MyoD and MyoG through the activation of voltage-gated calcium channels.

Expression and electrophysiological characteristics of VGSC during mouse myoblasts differentiation

Voltage-gated sodium channels (VGSC) are essential for triggering and relaying action potentials (AP), which perform critical functions in a variety of physiological processes, such as controlling muscle contractions and facilitating the release of neurotransmitters. In this study, we used a mouse C2C12 cell differentiation model to study the molecular expression and channel dynamics of VGSC and to investigate the exact role of VGSC in the development of muscle regeneration. Immunofluorescence, Real-time quantitative polymerase chain reaction, Western blot, and whole-cell patch clamp were employed for this purpose in mouse myoblasts. The findings revealed an increase in intracellular sodium concentration, NaV1.4 gene expression, and protein expression with the progress of differentiation (days 0, 1, 3, 5 and 7). Furthermore, VGSC dynamics exhibit the following characteristics: ① The increase of sodium current (INa); ② The decrease in the activation threshold and the voltage trigger maximum of INa; ③ A positive shift in the steady-state inactivation curve; ④ The recovery of INa during repolarization is delayed, the activity-dependent decay rate of INa was accelerated, and the proportionate amount of the fraction of activated channels was reduced. Based on these results, it is postulated that the activation threshold of AP could be decreased, and the refractory period could be extended with the extension of differentiation duration, which may contribute to muscle contraction. Taken together, VGSC provides a theoretical and empirical basis for exploring potential targets for neuromuscular diseases and other therapeutic muscle regeneration dysfunctions.

Cordycepin inhibits myogenesis via activating the ERK1/2 MAPK signalling pathway in C2C12 cells

Cordycepin (with a molecular formula of C10H13N5O3), a natural adenosine isolated from Cordyceps militaris, has an important regulatory effect on skeletal muscle remodelling and quality maintenance. The aim of this study was to investigate the effect of cordycepin on myoblast differentiation and explore the underlying molecular mechanisms of this effect. Our results showed that cordycepin inhibited myogenesis by downregulating myogenic differentiation (MyoD) and myogenin (MyoG), preserved undifferentiated reserve cell pools by upregulating myogenic factor 5 (Myf5) and retinoblastoma-like protein p130 (p130), and enhanced energy reserves by decreasing intracellular reactive oxygen species (ROS) and enhancing mitochondrial membrane potential, mitochondrial mass, and ATP content. The effect of cordycepin on myogenesis was associated with increased phosphorylation of extracellular signal-regulated kinase 1/2 (p-ERK1/2). PD98059 (a specific inhibitor of p-ERK1/2) attenuated the inhibitory effect of cordycepin on C2C12 differentiation. The present study reveals that cordycepin inhibits myogenesis through ERK1/2 MAPK signalling activation accompanied by an increase in skeletal muscle energy reserves and improving skeletal muscle oxidative stress, which may have implications for its further application for the prevention and treatment of degenerative muscle diseases caused by the depletion of depleted muscle stem cells.

Cordycepin protects islet β-cells against glucotoxicity and lipotoxicity via modulating related proteins of ROS/JNK signaling pathway

Type 2 diabetes mellitus (T2DM) is a common and multiple endocrine metabolic disease. When pancreatic β cell in case of dysfunction, the synthesis and secretion of insulin are reduced. This study is to explore the effect of cordycepin (the molecular formula C₁₀H₁₃N₅O₃), a natural adenosine isolated from Cordyceps militaris, on high glucose/lipid-induced glucotoxicity and lipotoxicity in INS-1 cells. Our results showed that cordycepin improved cell viability, improved cell energy metabolism and promoted insulin synthesis and secretion. The mechanism may be related to that cordycepin reduces intracellular reactive oxygen species (ROS), increases ATP content in cells, causes membrane depolarization and balances the steady state of Ca²⁺ concentration, cordycepin inhibits cell apoptosis, which may be related to the downregulation of proteins level of c-Jun N-terminal kinases (JNK) phosphorylation, cytochrome c (Cyt-c), Cleaved Capase-3, the mRNA level of JNK, Cyt-c, Capase-3 and upregulation of proteins/mRNA level of pancreatic and duodenal homeobox factor-1 (PDX-1). These results suggest that cordycepin can inhibit cell apoptosis and protect cell number by downregulating ROS/JNK mitochondrial apoptosis pathway under high glucose/lipid environment, thereby improving the function of pancreatic islet cells, providing a theoretical basis for the related research on the prevention and control of cordycepin on T2DM.

Cordycepin suppresses glutamatergic and GABAergic synaptic transmission through activation of A1 adenosine receptor in rat hippocampal CA1 pyramidal neurons

Cordycepin (known as 3-deoxyadenosine, CRD), a natural product from the valuable traditional Chinese medicine Cordyceps militaris, has been reported to improve cognitive function and modulate neuroprotective effects on the central nervous system (CNS). However, the modulating mechanisms of cordycepin on information processing in hippocampal CA1 pyramidal neurons are not fully understood. To clarify how cordycepin modulates synaptic responses of pyramidal neurons in rat hippocampal CA1 region, we conducted an electrophysiological experiment using whole-cell patch-clamp technique. The spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs, respectively) and the spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs, respectively) recorded by this technique evaluated pure single or multi-synapse responses and enabled us to accurately quantify how cordycepin influenced the pre and postsynaptic aspects of synaptic transmission. The present results showed that cordycepin significantly decreased the frequency of both glutamatergic and GABAergic postsynaptic currents without affecting the amplitude, while these inhibitory effects were antagonized by the A₁ adenosine receptor antagonist (DPCPX), but not the A_2A (ZM 241385), A_2B (MRS1754) and A₃ (MRS1191) adenosine receptor antagonists. Taken together, our results suggested that cordycepin had a clear presynaptic effect on glutamatergic and GABAergic transmission, and provided novel evidence that cordycepin suppresses the synaptic transmission through the activation of A₁AR.

TRPM7 is critical for short-term synaptic depression by regulating synaptic vesicle endocytosis

Transient receptor potential melastatin 7 (TRPM7) contributes to a variety of physiological and pathological processes in many tissues and cells. With a widespread distribution in the nervous system, TRPM7 is involved in animal behaviors and neuronal death induced by ischemia. However, the physiological role of TRPM7 in central nervous system (CNS) neuron remains unclear. Here, we identify endocytic defects in neuroendocrine cells and neurons from TRPM7 knockout (KO) mice, indicating a role of TRPM7 in synaptic vesicle endocytosis. Our experiments further pinpoint the importance of TRPM7 as an ion channel in synaptic vesicle endocytosis. Ca2+ imaging detects a defect in presynaptic Ca2+ dynamics in TRPM7 KO neuron, suggesting an importance of Ca2+ influx via TRPM7 in synaptic vesicle endocytosis. Moreover, the short-term depression is enhanced in both excitatory and inhibitory synaptic transmissions from TRPM7 KO mice. Taken together, our data suggests that Ca2+ influx via TRPM7 may be critical for short-term plasticity of synaptic strength by regulating synaptic vesicle endocytosis in neurons.

Cordycepin protects against β-amyloid and ibotenic acid-induced hippocampal CA1 pyramidal neuronal hyperactivity

Cordycepin exerts neuroprotective effects against excitotoxic neuronal death. However, its direct electrophysiological evidence in Alzheimer's disease (AD) remains unclear. This study aimed to explore the electrophysiological mechanisms underlying the protective effect of cordycepin against the excitotoxic neuronal insult in AD using whole-cell patch clamp techniques. β-Amyloid (Aβ) and ibotenic acid (IBO)-induced injury model in cultured hippocampal neurons was used for the purpose. The results revealed that cordycepin significantly delayed Aβ + IBO-induced excessive neuronal membrane depolarization. It increased the onset time/latency, extended the duration, and reduced the slope in both slow and rapid depolarization. Additionally, cordycepin reversed the neuronal hyperactivity in Aβ + IBO-induced evoked action potential (AP) firing, including increase in repetitive firing frequency, shortening of evoked AP latency, decrease in the amplitude of fast afterhyperpolarization, and increase in membrane depolarization. Further, the suppressive effect of cordycepin against Aβ + IBO-induced excessive neuronal membrane depolarization and neuronal hyperactivity was blocked by DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A₁ receptor-specific blocker). Collectively, these results revealed the suppressive effect of cordycepin against the Aβ + IBO-induced excitotoxic neuronal insult by attenuating excessive neuronal activity and membrane depolarization, and the mechanism through the activation of A₁R is strongly recommended, thus highlighting the therapeutic potential of cordycepin in AD.

[Study on Material Basis and Mechanism of Erzhi Wan prevent Alzheimer's disease by network pharmacology]

The present study is to explore the material basis and mechanism of Erzhi Wan the prevented Alzheimer's disease by using network pharmacology. The key target of Alzheimer's disease was docked with the Erzhi Wan compounds, and the drugs-target combined with target-signal pathway network model was established by Cytoscape 3.2.1 software. Thirty compounds have a strong interaction with key target of Alzheimer's disease and three key pathways related with Wnt, MAPK and PI3K-Akt-mTOR. There are 5 ingredients such as quercetin,geraniol,beta-sitosterol,nerol,eriodictyol that could be verified from literature.This result initially revealed the material basis for Erzhi Wan for Alzheimer's disease and the mechanism in terms of three signaling pathways. The network pharmacology method found that the active ingredients of Erzhi Wan for Alzheimer's disease may be quercetin,geraniol,beta-sitosterol,nerol,and eriodictyol, and the mechanism may be related to three signal pathways including Wnt, MAPK, and PI3K-Akt-mTOR.

[The expressions and diagnostic values of miR-18a and miR-21 in esophageal cancer]

Objective: To investigate the expressional levels and diagnostic values of miR-18a and miR-21 in esophageal carcinoma. Methods: The expressions of miR-18a and miR-21 in esophageal cancer tissues and adjacent tissues from 45 esophageal cancer patients, peripheral blood from 45 esophageal cancer patients and 50 healthy donors respectively were detected by RT-PCR. The expressions of miR-18a and miR-21 in normal esophageal epithelial cell HET-1A, esophageal cancer cell lines including ECA109, KYSE150 and TE1 were also detected. Chemiluminescence immunoassay was used to quantitatively detect the concentrations of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), CYRFA21-1 and TPA (tissue polypeptide antigen) in peripheral blood serum from esophageal cancer patients and healthy controls. Meanwhile, the diagnostic effects of miR-18a and miR-21 on esophageal cancer were compared with those of tumor markers in serum. Results: The expression levels of miR-18a and miR-21 in esophageal cancer cells ECA109, KYSE150 and TE1 were 1.64±0.17, 1.62±0.19, 1.46±0.12 and 20.52±1.48, 6.73±0.73, 1.43±0.19, respectively, higher than those in normal esophageal epithelial cells (both P<0.01). The expressions of miR-18a and miR-21 in esophageal cancer tissues were 32.48±28.62 and 8.67±11.98, respectively, significantly higher than those in adjacent tissues (all P<0.001). The expression levels of miR-18a and miR-21 in peripheral blood of patients with esophageal cancer were 12.66±11.92 and 9.15±8.14, respectively, significantly higher than those in the normal control group (both P<0.001). The receiver operating characteristic (ROC) curve analysis showed that the area under the curve of miR-18a and miR-21 for diagnosis of esophageal cancer were 0.948 and 0.913 5, respectively. Compared with traditional esophageal tumor markers, the expressions of miR-18a and miR-21 were more sensitive in the diagnosis of esophageal cancer. The sensitivity and accuracy of the expressions of miR-18a and miR-21 combined with traditional esophageal tumor markers in diagnosis of esophageal cancer can be further improved to 97.8% and 68.4%, respectively. Conclusion: Our study reveals that the expressions of miR-18a and miR-21 play important roles in the diagnosis of esophageal cancer and may be potentially novel biomarkers.

[Central cholinergic system innervates song control system of songbirds and regulates song behavior]

Songbird has become an ideal model for studying motor learning due to its unique learned song behavior. It has been proved that song behavior is directly regulated by song control system in the forebrain of songbirds. There are lines of evidence to show that cholinergic transmitters and their receptors are distributed in song control system, and vocal control nuclei in song control system are innervated by cholinergic nerves from the central cholinergic system in basal forebrain, which can affect activities of vocal control nuclei through cholinergic transmitters, and then affect song behavior. Studies in mammals have confirmed that the central cholinergic system is involved in the regulation of motor behavior and neural process of motor learning. Elucidation of regulation of songbirds' song behavior by central cholinergic system would shed light on the neural mechanism of song motor control and song learning and memory in songbirds, and provide theoretical insights for researches on other animals' sensorimotor processes and human language learning. This review summarized recent progresses, including the research work of our laboratory, in the studies on the selectivity of cholinergic transmitters to their receptors and their effects on neuronal activities in vocal control nuclei of songbirds and provided valuable clues for revealing the regulation mechanism of central cholinergic system on songbirds' song behavior.

Voltage-Gated Na+ Channels are Modulated by Glucose and Involved in Regulating Cellular Insulin Content of INS-1 Cells

Background/Aims: Islet beta cells (β-cells) are unique cells that play a critical role in glucose homeostasis by secreting insulin in response to increased glucose levels. Voltage-gated ion channels in β-cells, such as K+ and Ca2+ channels, contribute to insulin secretion. The response of voltage-gated Na+ channels (VGSCs) in β-cells to the changes in glucose levels remains unknown. This work aims to determine the role of extracellular glucose on the regulation of VGSC. Methods: The effect of glucose on VGSC currents (INa) was investigated in insulin-secreting β-cell line (INS-1) cells of rats using whole-cell patch clamp techniques, and the effects of glucose on insulin content and cell viability were determined using Enzyme-Linked Immunosorbent Assay (ELISA) and Methylthiazolyldiphenyl-tetrazolium Bromide (MTT) assay methods respectively. Results: Our results show that extracellular glucose application can inhibit the peak of INa in a concentration-dependent manner. Glucose concentration of 18 mM reduced the amplitude of INa, suppressed the INa of steady-state activation, shifted the steady-state inactivation curves of INa to negative potentials, and prolonged the time course of INa recovery from inactivation. Glucose also enhanced the activity-dependent attenuation of INa and reduced the fraction of activated channels. Furthermore, 18 mM glucose or low concentration of tetrodotoxin (TTX, a VGSC-specific blocker) partially inhibited the activity of VGSC and also improved insulin synthesis. Conclusion: These results revealed that extracellular glucose application enhances the insulin synthesis in INS-1 cells and the mechanism through the partial inhibition on INa channel is involved. Our results innovatively suggest that VGSC plays a vital role in modulating glucose homeostasis.

Targeted ultrasound molecular imaging in mouse atherosclerotic plaque model

This study aims to assess the early diagnosis of mouse atherosclerotic plaque through targeted ultrasound molecular imaging. Forty Apolipoprotein E-deficient (ApoE-/-) mice and 40 C57BL/6 wild type mice were randomly divided into 4 groups, 20 mice per group. Mice included in the study group were fed with high cholesterol diet for 20 weeks, after which the targeted ultrasound microbubbles were prepared. The mice with atherosclerotic plaque were studied with targeted ultrasound molecular imaging in comparison with red oil O staining. The results of targeted ultrasound molecular imaging of atherosclerotic plaque indicate that the GP Ib and GP IIb/IIIa are viable biomarkers for early diagnosis of vulnerable atherosclerotic plaque. The targeted ultrasound molecular imaging is worth studying in order to identify the atherosclerotic progress as a noninvasive effective identification method which could be used widely.

The supersonic molecular beam injector as a reliable tool for plasma fueling and physics experiment on HL-2A

On HL-2A tokamak, supersonic molecular beam injection (SMBI) has been developed as a routine refueling method. The key components of the system are an electromagnetic valve and a conic nozzle. The valve and conic nozzle are assembled to compose the simplified Laval nozzle for generating the pulsed beam. The appurtenance of the system includes the cooling system serving the cooled SMBI generation and the in situ calibration component for quantitative injection. Compared with the conventional gas puffing, the SMBI features prompt response and larger fueling flux. These merits devote the SMBI a good fueling method, an excellent plasma density feedback control tool, and an edge localized mode mitigation resource.

Effect of high ovarian response on the expression of endocrine gland-derived vascular endothelial growth factor (EG-VEGF) in peri-implantation endometrium in IVF women

OBJECTIVE

To investigate the effect of ovarian stimulation on the expression of EG-VEGF mRNA and protein in peri-implantation endometrium in women undergoing IVF and its relation with endometrial receptivity (ER).

DESIGN

Prospective laboratory study.

SETTING

University hospital.

PATIENTS

Eighteen women in stimulated cycles (SC) as study subjects and 18 women in natural cycles (NC) as controls. Women in SC group were classified with two subgroups, high ovarian response (SC1, n=9) with peak serum E2>5,000 pg/mL and moderate ovarian response (SC2, n=9) with peak serum E2 1,000-5,000 pg/mL.

INTERVENTION(S)

Endometrial biopsies were collected 6 days after ovulation in NC or after oocyte retrieval in SC.

MAIN OUTCOME MEASURE(S)

Endometrium histological dating was observed with HE staining. EG-VEGF mRNA expression levels determined by real-time polymerase chain reaction analysis, and protein levels by immunohistochemistry.

RESULTS

All endometrial samples were in the secretory phase. The endometrial development in SC1 was 1 to 2 days advanced to NC, and with dyssynchrony between glandular and stromal tissue. Immunohistochemistry analysis showed that EG-VEGF protein was predominantly expressed in the glandular epithelial cells and endothelial cells of vessels, and also presented in the stroma. The image analysis confirmed that both the gland and stroma of endometrium in SC1 had a significantly lower EG-VEGF protein expression than that in SC2 and NC endometrium. Moreover, EG-VEGF mRNA levels were significantly lower in SC1 than in NC. Both EG-VEGF protein and mRNA levels had no significant difference between SC2 and NC.

CONCLUSION

Decreased expression of EG-VEGF in the peri-implantation is associated with high ovarian response, which may account for the impaired ER and lower implantation rate in IVF cycles.

Modulation effects of cordycepin on the skeletal muscle contraction of toad gastrocnemius muscle

Isolated toad gastrocnemius muscle is a typical skeletal muscle tissue that is frequently used to study the motor system because it is an important component of the motor system. This study investigates the effects of cordycepin on the skeletal muscle contractile function of isolated toad gastrocnemius muscles by electrical field stimulation. Results showed that cordycepin (20 mg/l to 100 mg/l) significantly decreased the contractile responses in a concentration-dependent manner. Cordycepin (50 mg/l) also produced a rightward shift of the contractile amplitude-stimulation intensity relationship, as indicated by the increases in the threshold stimulation intensity and the saturation stimulation intensity. However, the most notable result was that the maximum amplitude of the muscle contractile force was significantly increased under cordycepin application (122±3.4% of control). This result suggests that the skeletal muscle contractile function and muscle physical fitness to the external stimulation were improved by the decreased response sensitivity in the presence of cordycepin. Moreover, cordycepin also prevented the repetitive stimulation-induced decrease in muscle contractile force and increased the recovery amplitude and recovery ratio of muscle contraction. However, these anti-fatigue effects of cordycepin on muscle contraction during long-lasting muscle activity were absent in Ca2+-free medium or in the presence of all Ca2+ channels blocker (0.4 mM CdCl2). These results suggest that cordycepin can positively affect muscle performance and provide ergogenic and prophylactic benefits in decreasing skeletal muscle fatigue. The mechanisms involving excitation-coupled Ca2+ influxes are strongly recommended.

Cordycepin suppresses excitatory synaptic transmission in rat hippocampal slices via a presynaptic mechanism

AIMS

Cordycepin plays an important role in modulating the function of central nervous system (CNS). However, the modulating mechanism is poorly understood. Excitatory synaptic transmission, the essential process in brain physiology and pathology, is critical in the signal integration activities of the CNS. To further understand the effects of cordycepin on CNS, we investigated the effects of cordycepin on excitatory synaptic transmission in the CA1 region of rat hippocampal slices.

METHODS

The effects of cordycepin on excitatory synaptic transmission were investigated by using in vitro field potential electrophysiology and whole-cell patch clamp techniques.

RESULTS

Cordycepin significantly decreased the amplitudes of field excitatory postsynaptic potentials (fEPSPs) elicited in the CA1 by stimulation of the Schaffer-commissural fibers. And the reduction in fEPSPs amplitude was associated with an increase in the paired-pulse facilitation. Cordycepin also suppressed α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and N-methyl-d-aspartic acid (NMDA) receptor-mediated responses but did not directly affect AMPA receptors and NMDA receptors. Furthermore, quantal analysis revealed that cordycepin decreased the frequency but not amplitude of miniature spontaneous excitatory postsynaptic currents.

CONCLUSIONS

These results demonstrate that cordycepin suppresses excitatory synaptic transmission by decreasing the excitatory neurotransmitter release presynaptically, which provides an evidence for the novel potential mechanism of cordycepin in modulating the function of CNS.

Flash fixation of heavy metals from two industrial wastes into ferrite by microwave hydrothermal co-treatment

Flash fixation of heavy metals from electroplating wastewater (EPW) and pickling waste liquor (PWL) into ferrite lattice can be investigated by microwave hydrothermal process. The toxicity of wastewater may be reduced by the redox reaction between Cr(VI) in electroplating wastewater and Fe(II) in pickling waste liquor. Box-Behnken design (BBD) experiment gives optimal process condition of ferrite formation as follows: wastewater volume ratio (V(PWL):V(EPW) = 0.20), pH value 11 and retention time 15 min, on which formed ferrite has a soft magnetic property with high saturation magnetization (M(s)) 47.4 emu/g. The rapid ferrite process has lower activation energy 7.01 kJ/mol according to grain growth kinetics. Concerning the environmental and economy, we introduced a new and interesting method for water remediation simultaneously synthesizing ferrite by using microwave mediated hydrothermal processes.

Cordycepin decreases activity of hippocampal CA1 pyramidal neuron through membrane hyperpolarization

Cordycepin (3'-deoxyadenosine) is the main functional component of Cordycepins militaris, a renowned traditional Chinese medicine, which has been shown to possess anti-tumor, anti-inflammatory, anti-diabetic and neuro-protective effects. However, the effect of cordycepin on the central nervous system (CNS) remains unclear. In this study, the effects of cordycepin on neuronal activity were investigated on the CA1 pyramidal neurons in rat hippocampal brain slices using a whole-cell patch clamp technique. Our results revealed that cordycepin significantly decreased the frequency of both the spontaneous and evoked action potential (AP) firing. While AP spike width, the amplitude of fast after hyperpolarization (fAHP), and membrane input resistance were not altered by cordycepin, the neuronal membrane potential was hyperpolarized by cordycepin. Collectively, these results demonstrate that cordycepin reduces neuronal activity by inducing membrane hyperpolarization, indicating that cordycepin may be a potential therapeutic strategy for ischemic and other excitotoxic disorders.

Observation of a spontaneous particle-transport barrier in the HL-2A tokamak

Using the profile analysis, the density perturbation transport analysis, and the Doppler reflectometry measurement, for the first time a spontaneous and steady-state particle-transport barrier has been evidenced in the Ohmic plasmas in the HL-2A tokamak with no externally applied momentum or particle input except the gas puffing. A threshold in density has been found for the observation of the barrier. The particle diffusivity is well-like, and the convection is found to be inward outside the well and outward inside the well. The formation of the barrier coincides with the transition between the trapped electron mode and the ion temperature gradient driven mode.

A method of particle transport study using supersonic molecular beam injection and microwave reflectometry on HL-2A tokamak

A method of the particle transport study using supersonic molecular beam injection (SMBI) and microwave reflectometry is reported in this paper. Experimental results confirm that pulsed SMBI is a good perturbation source with deeper penetration and better localization than the standard gas puffing. The local density modulation is induced using the pulsed SMBI and the perturbation density is measured by the microwave reflectometry. Using Fourier transform analysis for the local density perturbation, radial profiles of the amplitude and phase of the density modulation can be obtained. The experimental results in HL-2A show that the particle injected by SMBI is located at about r/a=0.65-0.75. The position of the main particle source can be determined through three aspects: the minimum of the phase of the first harmonic of the Fourier transform of the modulated density measured by microwave reflectometry; the H(a) intensity profile and the local density increase ratio. The maximum of the amplitude of the first harmonic shifts often inward relative to the particle source location, which indicates clearly there is an inward particle pinch in this area. Good agreement has been found between the experimental results and the simulation using analytical transport model. The particle diffusivity D and the particle convection velocity V have been obtained by doing this simulation. The sensitivity in the transport coefficients of the amplitude and the phase of the density modulation has been discussed.

[Prognostic value of cyclin E and its relation to blood vessel invasion in rectal cancer]

OBJECTIVE

To investigate the expression of cyclin E in rectal carcinoma and its prognostic significance.

METHODS

Cyclin E expression was examined by Western blotting in tumor tissue samples from 130 potentially resected rectal cancer patients with pathological stages I- III. Blood vessel invasion (BVI) was detected by immunohistochemistry. Multivariate analysis using the COX proportional hazards models was applied to evaluate the independent prognostic tumor markers of rectal cancer.

RESULTS

The high expression rate of cyclin E in rectal carcinoma tissue was 23.1%(30/130). Except for a positive correlation with BVI and the gross configuration of tumor, the expression of cyclin E showed no significant relation to other clinicopathological factors. The 5-year disease-specific survival rate of cyclin E high expression group was 29.2%, which was significantly lower as compared to that of cyclin low expression group 70.5% (P<0.05). Multivariate analysis revealed that histology and cyclin E expression were independent prognostic indicators for rectal cancer patients at stages I- III. Compared to those with low expression levels, patients with high cyclin E levels had the hazard ratio (95%CI) for death from rectal cancer for 3.544 (1.528-8.215). In stage I- II, multivariate analysis showed that stronger predictive values of cyclin E expression even were detected. Patients with low cyclin E expression and negative BVI had a significantly better prognosis than those with high cyclin E expression and positive BVI.

CONCLUSIONS

The expression of cyclin E is independent prognostic factor in rectal carcinoma at stages I- III. Detecting the expression of cyclin E and/or combined with BVI may help to predict clinical outcome and design further individualized intensive adjuvant treatment.

Flavonoids in food and their health benefits

There has been increasing interest in the research of flavonoids from dietary sources, due to growing evidence of the versatile health benefits of flavonoids through epidemiological studies. As occurrence of flavonoids is directly associated with human daily dietary intake of antioxidants, it is important to evaluate flavonoid sources in food. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. However, there is still difficulty in accurately measuring the daily intake of flavonoids because of the complexity of existence of flavonoids from various food sources, the diversity of dietary culture, and the occurrence of a large amount of flavonoids itself in nature. Nevertheless, research on the health aspects of flavonoids for humans is expanding rapidly. Many flavonoids are shown to have antioxidative activity, free-radical scavenging capacity, coronary heart disease prevention, and anticancer activity, while some flavonoids exhibit potential for anti-human immunodeficiency virus functions. As such research progresses. further achievements will undoubtedly lead to a new era of flavonoids in either foods or pharmaceutical supplements. Accordingly, an appropriate model for a precise assessment of intake of flavonoids needs to be developed. Most recent research has focused on the health aspects of flavonoids from food sources for humans. This paper reviews the current advances in flavonoids in food, with emphasis on health aspects on the basis of the published literature, which may provide some guidance for researchers in further investigations and for industries in developing practical health agents.

Expression of human vascular endothelial growth factor (VEGF165) in Pichia pastoris and its biological activity

OBJECTIVE

To express human vascular endothelial growth factor (hVEGF165) cDNA in Pichia pastroris, purify the expressed product and detect the biological activity of it.

METHODS

By inserting hVEGF165 cDNA coding 165 amino acid residues into Pichia pastoris expression vector pPIC9K containing AOX1 promoter and the sequences of alpha secreting signal peptides, a recombinant expression plasmid pPIC9K/hVEGF165 was constructed and transformed to yeast host strain KM71, then multiple-copy insert transformants were screened out and cultured in flasks, and hVEGF165 was expressed under the induction of 1% methanol.

RESULTS

SDS-PAGE showed that after being induced with 1% methanol for 4 d, the expressed product existed in supernatant in the form of soluble molecule and contained 60% of total protein expressed. Western blot showed good antigenicity and specificity of expressed product. After being purified by Heparin-Sepharose CL6B affinity chromatography, the purity of expressed product reached above 90%. Biological assays proved that the expressed product could stimulate the proliferation of HUVEC.

CONCLUSION

hVEGF165 was successfully expressed. The study opened up a wide prospect for the application of VEGF165 in the prevention and treatment of ischemic heart disease and other tissue ischemic diseases such as secondary arterial occlusion in limbs.

[Embolization of AVM of jaws]

OBJECTIVE

To report our experience to embolize the AVM of jaws by direct percutaneous puncture. in conjunction with endovascular therapy.

METHODS

3 cases of AVM of mandible and 3 cases of AVM of maxilla comprised this study group. The patients were embolized with fibered coils, PVA and NBCA. The coils were placed directly into the center of the intraosseous lesion. The procedure was under the guidance of DSA machine (PHILIPS V3000).

RESULTS

The acute arterial bleeding in 4 patients was controllable. The other two cases with oozing bleeding and a warm soft mass on the left face with a palpable pulse respectively, their symptoms and signs got improved a lot. The pericoronal oozing of blood in all patients disappeared during a 3 to 24 months follow-up and new bone formation was found in the follow-up radiography.

CONCLUSION

The embolization of the AVM of jaws by direct percutaneous puncture in conjunction with endovascular therapy is effective and safe, however the longer follow-up is expected.

[Cloning of VEGF receptor KDR and its expression in insect cells]

The cDNA fragment of the first 3 loops of VEGF receptor, KDR, was cloned by PCR and inserted into a baculovirus expression plasmid pFASTBACI. The competent E. coli DH10BAC cell, which contain another plasmid with baculovirus genome in it, was transformed with pFASTBACI-KDRn3. Homologous recombination in the prokaryotic cells resulted in a recombinant plasmid containing KDRn3 in baculovirus genome. Transfection of the insect cell SF-9 with above plasmid generated a recombinant baculorvirus contain target gene fragment. SDS-PAGE and Western blot analysis of the supernatant of the infected SF-9 cell showed that KDRn3 was secreted in the medium. The recombinant protein was verified with Western blot and tested for their binding activity with VEGF. Its anti-angiogenic activity was assayed on chorionic allantoic membrane(CAM) of fertilized egg. The results showed that the recombinant protein could inhibit new vessel formation on CAM of fertilized eggs.

[Expression and characterization of human vascular endothelial growth factor receptor Flt-1 extracellular domain in Pichia pastoris]

By inserting VEGF receptor Flt-1(1-3 loop) cDNA into Pichia pastoris expression vector pPIC9K containing AOX1 promotor and the sequences of alpha secreting signal peptides, the expression plasmid pPIC9K/Flt-1(1-3) was constructed and transformed into GS115. The multi-copy insert transformants were selected and cultivated in flasks. After 4 days of 1% methanol induction, the expressed Flt-1(1-3) accumulated up to 30% of total proteins in supernatant. The expressed Flt-1(1-3) was further proved with good antigenicity and high specificity by ELISA and Western blot. They can bind to VEGF and inhibit HUVEC proliferation stimulated by VEGF.

[Open operation of the vertical condylar fracture]

OBJECTIVE

This article is mentioned to study the incidence, diagnosis, management of the vertical condylar fractures.

METHODS

11 patients, 14 cases of the vertical condylar fractures, were treated in our department between June 1997 and August 1998. All the patients were diagnosed through history, physical examination, radiographs, computed tomography scan and three-dimensional reconstruction of a computed tomography scan, treated with various surgical approaches.

RESULTS

All the patients had got satisfactory postoperative result in the aspects of occlusion, degree of opening, joint noise, pain in the area of temporomandibular joint, deviation in mandibular motion and healing of the incision.

CONCLUSION

Enough attention should be paid to the vertical condylar fractures. The key to a successful open operation is the correct diagnosis, the accurate reduction and the stable fixation.

[The primary study of articulation effect on the adults with cleft palate undergoing palatopharyngoplasty]

A retrospective study was performed in 15 adults with cleft palate who operated with palato-pharyngoplasty.Using frequency spectrum analyser to describe their Chinese vowel frequency spectrum curve character.Their articulation effect after sugery was analyzed.The result shows:The excellent rate of the articulation on effect appears 46.67%.The author believes that:the palato-pharyngoplasty can be utilized as a manner to cure the adults with cleft palate and the advanced effect is needed to be continuously studied.

[Reconstruction of post-traumatic maxillofacial deformity: Analysis of 100 cases]

This paper collects 100 cases with post-traumatic maxillofacial deformity.The types of deformity may be involved by order to concave appearance restricted opening of jaw,disturbance of occlusion,mimetic paralysis,scar,etc.The author advocate the treatment must be paid attention both appearance and function.Recently,we have used the vascularized flap,coronary incision,orthognathic surgery and rigid internal fixation in these cases,and have gotten better result than past.This paper emphasizes that we should pay attention to emergency treatment to reduce the occur of post-traumatic deformity.

[Evaluation of velopharyngeal function after later surgical repair of cleft palate. ]

This study detected 60 cases of patients of later surgical cleft palate repairing with different operative procedures,based on nasopharyngeal fiberscope and image processing detective system of nasopharyngeal function.They were divided into two groups,30 cases with Furlow's double reversing Z plasty,and others with traditional palatoplasty.The results were as follows:the type of velopharyngeal closure with later palatoplasty mainly were circus,semi-circus,and the rate of operative success only was 46.6%,which was lower than other reports.Author described that compensation of lateral and posterior pharyngeal wall made the type of velopharyngeal closure.The elder the age,the more the compensation is.For the late cleft palate repair,although the variable surgical procedure made a condition for speech improvement, patients with later cleft palate repair still can't improve their phonation.

[A comparative study of velopharyngeal function after palatoplasty with different age group]

That the most suitable age of palatoplasty is still an argumentative question.The final purpose of palatoplasty is to obtain the satisfactory effectiveness is to obtain the satisfactory effectiveness of phonetic distinctness.So,early palatoplasty is suported by more more experts and patient's parents.This study detected 60 cases velopharyngeal function after traditional palatoplasty with two flaps,adopting nasopharyngeal fiberscope and detective system of image processing and quantitative analysis of velopharyngeal function,for long term evaluation of traditional palatoplasty with different operative success iin early palatoplasty group (less than 3 years old) was 80.0% while that in later palatoplasty group (more than 6 years old) was 53.3%.From other aspects of types of velopharyngeal competence,mobility of soft palate and rate of velopharyngeal coronary contraction,the author described advantages of early palatoplasty.