To achieve fast and accurate analysis of weak current signal of nanopore-based single molecule detection, we designed a real-time adaptive threshold data processing algorithm with data buffering technique and finite impulse response filtering. The system, which is designed based on the data processing algorithm, could realize real-time recognition and analysis of nanopore events during the data recording process. In order to verify the performance of the system, the ideal signals with different noise level (20-100 pA) and recording bandwidth (3 - 100 kHz) was generated. The results showed that the system was stable to analyze the generated signals even at high noise. In addition, the system was also suitable for the data recording conditions of low bandwidth and high sampling rate (250 kHz). The proposed nanopore data processing system was further applied in the Aerolysin nanopore experiment for the detection of poly(dA) 4 molecules. The results showed that the data processing system could be applied in real nanopore recording system with high accuracy and speed.

BACKGROUNDThe effects of triterpenic acid from Prunella vulgaris L. (TAP) on diabetes and its mechanism are uncertain. The aim of this study was to investigate the effects of TAP on antihyperglycemic, antioxidant, and pancreas-protective in streptozotozin (STZ)-diabetic rats.

METHODSThe diabetic model was produced by injection of 60 mg/kg STZ. Blood was drawn from the tail vein of rats after 72 hours. Rats with blood glucose ≥ 16.7 mmol/L were considered diabetic. Diabetic rats were randomly divided into four groups: (1) Diabetes rat (STZ), (2) Diabetic rats treated with 50 mg/kg of triterpenic acid from Prunella vulgaris L (STZ + TAP50), (3) Diabetic rats treated with 100 mg/kg TAP (STZ + TAP100), and (4) Diabetic rats treated with 200 mg/kg TAP (STZ + TAP200). Normal rats (n = 10) acted as the control group (NC). TAP was administered by the intragastric route once each day for six weeks. Body weight and the concentration of blood glucose (BG) were measured after three and six weeks. Fructosamine (FMN), malondialdehyde (MDA), and nitric oxide (NO), and the activities of nitric oxide synthase (NOS) and superoxide dismutase (SOD) in serum were determined after six weeks using commercially available kits following the manufacturer's instructions. Pathologic changes in pancreatic β-cells were also investigated by microscopic examination after hematoxylin-eosin (HE) staining. The level of SOD mRNA in pancreatic β-cells was measured by polymerase chain reaction (PCR).

RESULTSThe levels of BG, FMN, NO, and MDA and the activities of NOS in serum in the four diabetes groups were significantly increased compared with the control group (P < 0.01). The activity of SOD in serum and the body weight was significantly decreased compared with the control group (P < 0.01). After administration of TAP to diabetic rats for six weeks, the body weight and the levels of BG, FMN, MDA, NO and the activity of NOS in serum decreased significantly compared with the STZ group in a dose-dependent manner. The activity of SOD in serum and body weight increased significantly compared with the STZ group in a dose-dependent manner. In addition, diabetic rats showed a significant decrease in SOD mRNA expression in pancreatic β cells. However, these changes were reversed by TAP. Histopathological examination also showed the protective effect of TAP on pancreatic β cells.

CONCLUSIONSTriterpenic acid from Prunella vulgaris L. has an anti-diabetic effect, by controlling blood glucose and antioxidants, and has a protective effect on the pancreas.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Insulin-Secreting Cells ; drug effects ; pathology ; Male ; Prunella ; chemistry ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Streptozocin ; Superoxide Dismutase ; genetics ; Triterpenes ; therapeutic use

OBJECTIVE: To study the effects of ketamine and alcohol on learning and memory in mice and its possible mechanism. METHODS: Forty mice were divided into 4 groups: normal control group, ketamine group, alcohol group, and alcohol plus ketamine group. Ketamine and alcohol were given by intraperitoneal injection and intragastric administration, respectively, 1 time per day, for 14 days. The ability of learning and memory in mice was tested by the method of step-down and Morris water maze. Acetylcholine (ACh) and 5-hydroxy tryptamine(5-HT) in mice brain tissue were analyzed for the possible mechanism. RESULTS: (1) Step-down: The treatment groups lessened the latency and added wrong times (P < 0.05). The number of errors in the combined treatment group significantly increased comparing with the single drug treatment group (P < 0.05). (2) Morris water-maze: The treatment groups prolonged the latency (P < 0.05), reduced the target quadrant activity time significantly (P < 0.05), and decreased the numbers of crossing the former platform significantly (P < 0.05). (3) Biochemical index determination: The concentrations of ACh and 5-HT in treatment groups decreased significantly (P < 0.05), showed a more decreasement comparing with the single drug treatment group. CONCLUSION Ketamine has a synergistic effect with alcohol on learning and memory impairment in mice, which may be related to the common inhibitive effect on the ACh and 5-HT.
Acetylcholine/metabolism* ; Alcohols/pharmacology* ; Animals ; Brain/physiopathology* ; Drug Synergism ; Ketamine/pharmacology* ; Male ; Maze Learning/drug effects* ; Memory/drug effects* ; Memory Disorders/physiopathology* ; Mice ; Mice, Inbred ICR ; Serotonin/metabolism* ; Spatial Behavior/drug effects*

OBJECTIVETo construct the plasmid reference molecules for detection of transgenic tomato line Zeneca B,Da,F using quantitative real-time PCR(qPCR).

METHODSThree plasmid reference molecules pEasy-T3-APX, pEasy-T3-16A and pEasy-T3-16S were cloned based on reverse genetics, which contain the target fragments of tomato endogenous reference gene apx (ERG-apx), gene-specific sequence of pg(GS-pg) and construct-specific sequence of vectors pJR16S/pJR16A (CS-16S/CS-16A) of Zeneca B,Da,F, respectively. Primers and Taqman probes were designed by Beacon Designer 7.5.The specificity, sensitivity, reproducibility and the limit of detection(LOD) of the qualitative and quantitative PCR system based on the plasmid reference molecules were evaluated. PicoGreen was used to measure the DNA concentration of the plasmid reference molecules. Two sets of samples containing 1% or 0.1% (w/w) pEasy-T3-16A or pEasy-T3-16S mixed with pEasy-T3- APX as background DNA were prepared for evaluating the efficacy of the qPCR system.

RESULTSThe target fragments for qPCR detection were anchored, ERG-apx 108 bp, GS-pg 108 bp , CS-16S 109 bp and CS-16A 102 bp. The three plasmid reference molecules were confirmed at the expected sizes by restriction enzyme digestion. The qPCR results showed that the RSD of reproducibility were 0.2% to1.5%, LOD was 25 copies, R2 values for these standard curves were 0.994 ~0.998 and amplification efficiencies were 93.3%~102.4%.The bias between the test and true values of two sets of mixed samples ranged from -9.3% to 14.7% after adjusting by conversion factors(Cf).

CONCLUSIONThe plasmid reference molecules and qPCR system for qualitative and quantitative detection of transgenic tomato line Zeneca B,Da,F have been established successfully.

Base Sequence ; DNA, Plant ; genetics ; Lycopersicon esculentum ; genetics ; Plants, Genetically Modified ; genetics ; Plasmids ; Real-Time Polymerase Chain Reaction ; methods

OBJECTIVE: To explore the effect of ketamine on adrenal pheochromocytoma (PC12) cell proliferation inhibition and induction of apoptosis and its mechanism. METHODS: PC12 cells of rats were models for dopaminergic neuron. PC12 cells were cultured with ketamine at concentrations of 0.9, 1.2, 1.5, 1.8 and 2.1 mmol/L, respectively. The cell viability was measured by MTT method after incubation at 12, 24, 48 and 72h. Hoechst stain was used to observe the morphological changes of apoptosis. PC12 cells cultured after 48 h with different concentrations of ketamine were selected to detect apoptotic rate using flow cytometry and detect the expression of bax and bcl-2 proteins using Western blotting. RESULTS: For different concentrations of ketamine, vitality of PC12 cells significantly decreased with increase of the incubation time. Apoptosis was obviously observed using Hoechst staining. Flow cytometry showed that apoptosis rates significantly increased with increasing ketamine concentrations. CONCLUSION Ketamine can inhibit the proliferation of PC12 cell by inducing apoptosis of the PC12 cell in a concentrations-dependent manner. The underlying mechanism may be related to promoting the expression of bax and inhibiting the expression of bcl-2 in the cells.
Anesthetics, Dissociative/pharmacology* ; Animals ; Apoptosis/drug effects* ; Blotting, Western ; Cell Proliferation/drug effects* ; Dose-Response Relationship, Drug ; Flow Cytometry ; Gene Expression Regulation/drug effects* ; Ketamine/pharmacology* ; PC12 Cells ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats ; Time Factors ; bcl-2-Associated X Protein/metabolism*

BACKGROUNDUrsolic acid (UA) is a ubiquitous molecule in the plant kingdom with specific anticancer effects that have been shown in vitro and in vivo. Although UA can inhibit the proliferation of liver cancer cells and induce apoptosis of many types of tumor cells, the molecular mechanism of its anti-hepatoma activity is still not well defined. The objective of this study was to investigate the inhibitory effect and mechanisms of UA on the human hepatoma cell line SMMC-7721.

METHODSAfter treatment with UA, the growth inhibition of SMMC-7721 cells was assessed by MTT assay. Cells were also evaluated by flow cytometric analysis, Wright-Giemasa staining, Hoechst 33258 staining and transmission electron microscope after they were induced by UA. DNA microarray technology was used to investigate the gene expression pattern of SMMC-7721 cells exposed to UA 40 micromol/L. The molecular mechanism of cells death was analyzed by real-time RT-PCR and Western blotting.

RESULTSThe proliferation of SMMC-7721 cells was significantly inhibited in a dose- and time-dependent manner after UA treatment. UA induced cell cycle arrest and apoptosis. The DNA microarray analysis indicated that 64 genes were found to be markedly up- or down-expressed, including GDF15, SOD2, ATF3, and fos. The result of Western blotting showed the apoptotic proteins p53 and Bax were up-regulated while the anti-apoptotic protein Bcl-2 was down-regulated. Real-time RT-PCR confirmed UA could up-regulate the mRNA expressions of GDF15, SOD2, ATF3 and down-regulate the mRAN expression of fos. Meanwhile these effects were partly blocked by pretreatment with the p53 inhibitor Pft-alpha.

CONCLUSIONActivation of the p53 pathway is involved in UA inhibition of SMMC-7721 human hepatocellular carcinoma cell growth and induction of apoptosis.

Apoptosis ; drug effects ; Blotting, Western ; Carcinoma, Hepatocellular ; drug therapy ; metabolism ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Flow Cytometry ; Humans ; Liver Neoplasms ; drug therapy ; metabolism ; Microscopy, Electron, Transmission ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Triterpenes ; therapeutic use ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVE: To observe the symptoms similar to schizophrenia in mice after ketamine single or continuous injection and to evaluate the feasibility of schizophrenia model injected with different dose of ketamine. METHODS: A total of 40 male mice were randomly divided into 4 groups, which were injected intraperitoneally with physiological saline (control group), 25 mg/kg ketamine (low dose group), 50 mg/kg ketamine (middle dose group), and 100 mg/kg ketamine (high dose group) qd for 7 days continuously. The behavior changes of mice were observed. RESULTS: Hyperactivity, stereotyped behavior and ataxia (P < 0.01) were observed in high dose group after single injection. After continuous injection of ketamine for 7 days, the middle dose group showed hyperactivity, stereotyped behavior and ataxia (P < 0.05), stereotyped behavior and ataxia were more significant in high dose group (P < 0.01). CONCLUSION Ketamine can induce the symptoms similar to schizophrenia in mice after single or continuous injection. The symptoms induced by high dose ketamine will be more prominent and stable after continuous injection.
Animals ; Ataxia/pathology* ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Forensic Psychiatry ; Injections, Intraperitoneal ; Ketamine/administration & dosage* ; Male ; Mice ; Motor Activity/drug effects* ; Random Allocation ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; Schizophrenia/pathology* ; Stereotyped Behavior/drug effects*

Ketamine is a phencyclidine derivative acting primarily as a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) excitatory glutamate receptors. As a common intravenous anaesthetic in clinic, it is also increasingly abused because of its hallucination and addiction effects. Based on the pharmacological and toxicologic characteristics of ketamine and the acknowledged addiction mechanism of other abused drugs, this article reviews the possible addiction mechanism of the ketamine in the aspects of its enhanced effects and reward systems, the anatomic structures, the related receptors and the individual differences.
Anesthetics, Dissociative/adverse effects* ; Animals ; Brain/drug effects* ; Humans ; Illicit Drugs ; Ketamine/adverse effects* ; Mental Disorders/chemically induced* ; Rats ; Receptors, Dopamine/drug effects* ; Receptors, N-Methyl-D-Aspartate/drug effects* ; Substance-Related Disorders

OBJECTIVE: To explore the correlation between signs similar to schizophrenia in mice after ketamine administration and the expressions of NRG1 and ErbB4 mRNA in order to explain the possible pathogenesis of schizophrenia. METHODS: Fifty KM mice were randomly divided into 5 groups which were administered intraperitoneally with saline, clozapine and different dosages ketamine. The ketamine groups were administered intraperitoneally with low dosage (25 mg/kg), middle dosage (50 mg/kg) and high dosage (100 mg/kg) one time every day for 7 days. After administration of 100 mg/kg ketamine for 7 days, the clozapine group was introgastrically administered 20 mg/kg with clozapine one time every day for 7 days. The pathological changes of hippocampus neurons were observed by HE stain. The expressions of the NRG1 and ErbB4 mRNA in hippocampus were detected by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In the group with high dosage of ketamine, the levels of NRG1 and ErbB4 mRNA were significantly lower than that of the group with saline. CONCLUSION Ketamine may induce signs similar to schizophrenia in KM mice. The mechanism may be involved in the reduction of NRG1 and ErbB4 mRNA expression.
Animals ; Clozapine/therapeutic use* ; Disease Models, Animal ; Dose-Response Relationship, Drug ; ErbB Receptors/metabolism* ; Hippocampus/pathology* ; Ketamine/adverse effects* ; Male ; Mice ; Neuregulin-1/metabolism* ; Neurons/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Receptor, ErbB-4 ; Reverse Transcriptase Polymerase Chain Reaction ; Schizophrenia/genetics*

Schizophrenia is one of the common mental diseases. Because the mechanism of the schizophrenia is significantly complicated, the cause is still unknown. N-methyl-D-aspartate receptor antagonist can simulate the positive and negative symptoms, as well as the cognitive disorder of schizophrenia. Thus it has been widely used to establish the animal models of schizophrenia. The relationship of the three blocking agents of ion channels (phencyclidine, MK-801, ketamine) and the establishment of schizophrenia animal models is reviewed in this article.
Animals ; Behavior, Animal/drug effects* ; Brain/physiopathology* ; Consciousness Disorders/physiopathology* ; Disease Models, Animal ; Dizocilpine Maleate/pharmacology* ; Excitatory Amino Acid Antagonists/pharmacology* ; Humans ; Ketamine/pharmacology* ; Mice ; Phencyclidine/pharmacology* ; Rats ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; Schizophrenia/physiopathology*