[Electrophysiological characteristics of hippocampal postnatal early development mediated by AMPA receptors in rats].

The present study was aimed to investigate the electrophysiological characteristics of hippocampal postnatal early development mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in rats. Forty-eight Wistar rats were divided into postnatal 0.5-, 1-, 2- and 3-month groups (n = 12). Spontaneous excitatory postsynaptic currents (sEPSCs) and field excitatory postsynaptic potentials (fEPSPs) mediated by AMPA receptors were recorded to evaluate the changes in the intrinsic membrane properties of hippocampal CA1 pyramidal neurons by using patch-clamp and MED64 planar microelectrode array technique respectively. The results showed that, during the period of postnatal 0.5-3 months, some of the intrinsic membrane properties of hippocampal CA1 pyramidal neurons, such as the membrane capacitance (Cm) and the resting membrane potential (RMP), showed no significant changes, while the membrane input resistance (Rin) and the time constant (τ) of the cells were decreased significantly. The amplitude, frequency and kinetics (both rise and decay times) of sEPSCs were significantly increased during the period of postnatal 0.5-1 month, but they were all decreased during the period of postnatal 1-3 months. In addition, the range of evoked fEPSPs in hippocamal CA1 region was significantly expanded, but the fEPSP amplitudes were decreased significantly during the period of postnatal 0.5-3 months. Furthermore, the evoked fEPSPs could be significantly inhibited by extracellular application of the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). These results suggest that AMPA receptor may act as a major type of excitatory receptor to regulate synaptic transmission and connections during the early stage of hippocampal postnatal development, which promotes the development and functional maturation of hippocampus in rats.

Safety and efficacy of remote ischemic postconditioning after thrombolysis in patients with stroke.

OBJECTIVE: To determine the effect of remote ischemic postconditioning (RIPC) on patients with acute ischemic stroke (AIS) undergoing IV thrombolysis (IVT). METHODS: A single-center randomized controlled trial was performed with patients with AIS receiving IVT. Patients in the RIPC group were administered RIPC treatment (after IVT) during hospitalization. The primary endpoint was a score of 0 or 1 on the modified Rankin scale (mRS) at day 90. The safety, tolerability, and neuroprotection biomarkers associated with RIPC were also evaluated. RESULTS: We collected data from both the RIPC group (n = 34) and the control group (n = 34). The average duration of hospitalization was 11.2 days. There was no significant difference between 2 groups at admission for the NIH Stroke Scale score (p = 0.364) or occur-to-treatment time (p = 0.889). Favorable recovery (mRS score 0-1) at 3 months was obtained in 71.9% of patients in the RIPC group vs 50.0% in the control group (adjusted odds ratio 9.85, 95% confidence interval 1.54-63.16; p = 0.016). We further found significantly lower plasma S100-ß (p = 0.007) and higher vascular endothelial growth factor (p = 0.003) levels in the RIPC group than in the control group. CONCLUSIONS: Repeated RIPC combined with IVT can significantly facilitate recovery of nerve function and improve clinical prognosis of patients with AIS. CLINICALTRIALSGOV IDENTIFIER: NCT03218293. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that RIPC after tissue plasminogen activator treatment of AIS significantly increases the proportion of patients with an MRS score of 0 or 1 at 90 days.

HERG-F463L potassium channels linked to long QT syndrome reduce I(Kr) current by a trafficking-deficient mechanism.

1. Congenital long QT syndrome (LQTS) is a genetically heterogeneous disease. The aim of the present study was to identify the gene mutation in a Chinese family with LQTS and investigate the functional changes associated with the mutation. 2. Polymerase chain reaction and DNA sequencing were used to screen for the KCNH2 mutation in the proband. A mutant F463L HERG channel was expressed in HEK293 cells using a lipofectamine method. The IKr current was recorded using the whole-cell voltage clamp technique. Expression of HERG protein was detected by western blotting and the subcellular location of HERG channels in cell was analysed by confocal microscopy. 3. The novel heterozygous missense mutation F463L in KCNH2 was detected. We found that the F463L mutation did not lead to any expression of detectable I(Kr) current, which was consistent with western blotting analysis indicating that the F463L mutation only expressed a band at 135 kDa. When coexpressed with wild-type HERG, F463L HERG exhibited strong dominant-negative current suppression, resulting in a decrease in I(Kr) current density, and induced a positive shift in the voltage dependence of activation, as well as interference with trafficking of wild-type channel protein. The processing of the F463L channels was partly corrected in cells incubated in E4031. In addition, confocal microscopy demonstrated that F463L subunits could be inserted into the cell membrane when forming heteromultimeric channels with wild-type channel subunits. 4. The results of the present study suggest that the F463L mutation leads to loss of function in HERG through a dominant-negative effect caused by impaired trafficking of the channel.

The kinematic recovery process of rhesus monkeys after spinal cord injury.

After incomplete spinal cord injury (SCI), neural circuits may be plastically reconstructed to some degree, resulting in extensive functional locomotor recovery. The present study aimed to observe the post-SCI locomotor recovery of rhesus monkey hindlimbs and compare the recovery degrees of different hindlimb parts, thus revealing the recovery process of locomotor function. Four rhesus monkeys were chosen for thoracic hemisection injury. The hindlimb locomotor performance of these animals was recorded before surgery, as well as 6 and 12 weeks post-lesion. Via principal component analysis, the relevant parameters of the limb endpoint, pelvis, hindlimb segments, and joints were processed and analyzed. Twelve weeks after surgery, partial kinematic recovery was observed at the limb endpoint, shank, foot, and knee joints, and the locomotor performance of the ankle joint even recovered to the pre-lesion level; the elevation angle of the thigh and hip joints showed no obvious recovery. Generally, different parts of a monkey hindlimb had different spontaneous recovery processes; specifically, the closer the part was to the distal end, the more extensive was the locomotor function recovery. Therefore, we speculate that locomotor recovery may be attributed to plastic reconstruction of the motor circuits that are mainly composed of corticospinal tract. This would help to further understand the plasticity of motor circuits after spinal cord injury.

[Committed differentiation of transplanted bone derived mesenchymal stem cells and their potential to amend damaged liver functions: in vivo experiment with mice].

OBJECTIVE: To observe whether bone mesenchymal stem cells (MSCs) have the potential to transdifferentiate into functional hepatocyte-like cells in the special "niche" as well as the therapeutic feasibility to repair damaged liver in mice. METHODS: 20 nude mice were randomly divided into four groups (n = 5 in each group): Group A: 1.0 ml/kg of carbon tetrachloride (CCl(4)) (dissolved in olive oil by ratio of 1:1) was injected into the peritoneum of mice twice a week for 5 weeks. GFP-positive MSCs (1 x 10(6) cells) were injected into the caudal tail vein 1 week after the first dose of CCl(4); Group B: treated with CCl(4) as in A, but received the same volume of saline; Group C: normal nude mice with GFP-positive MSCs Transplanted in the same way as in A. Group D: normal controls. 4 weeks after the cell transplantation, all animal subjects were killed. Liver function tests (LFT), histology of HE and Masson staining as well as double immunofluorescent staining for GFP and albumin were studied in all groups. RESULTS: The hepatic fibrosis in group A & B confirmed the success of model for liver damage and there was no marked difference in the percent of the area occupied by collagen between two groups (10.5 +/- 1.5 vs 12.7 +/- 1.6, t = -2.238, P > 0.05). GFP-positive MSCs were mainly observed around portal area or interspace of lobules in group A. Some of GFP-positive cells also express albumin (35% +/- 7%). While in group B, C or D, there is no such findings. The level of serum albumin in group A was higher than that in group B (24.4 g/L +/- 3.3 g/L vs 18.6 g/L +/- 2.9 g/L, P < 0.05) while the level of ALT was also different between two groups (121 U/L +/- 21 U/L vs 192 U/L +/- 29 U/L, P < 0.05). CONCLUSION: The stimulus of persistent liver damage might enhances the migration of MSCs to the liver, in which some of the MSCs have the potential to transdifferentiate into hepatocyte-like cells. Transplantation of MSCs might amend the damaged tissue of host liver to a certain extent.

[Functional expression of congenital long QT syndrome related HERG mutation A561V in vitro].

OBJECTIVE: To investigate the functional expression of HERG mutation A561V detected in a Chinese congenital long QT syndrome family. METHODS: The mutation gene A561V was cloned into eukaryotic expressive vector pcDNA3 by quick site-directed mutagenesis PCR and restriction enzymes. The wild-type HERG, heterozygous type HERG and HERG mutation A561V were respectively cotransfected with pRK5-GFP into HEK293 cells by Suprefact transfection regent. The protein expression was measured by immunofluorescence method and Western blot. The electrophysiological characteristics of transfected cells were determined by whole cell patch-clamp technique. RESULTS: Direct sequence analyses revealed a C to T transition at position 1682. A561V mutation was correctly combined to eukaryotic expressive vector pcDNA3 and expressed in HEK293 cells. The protein expression of mutation and heterozygosis were located in cytoplasm and cellular membrane. 155 kDa and 135 kDa protein bands were detected in wild type HERG channel while only 135 kDa protein band was shown in heterozygous and mutational channels. Significant HERG tail-current was recorded in wild type HERG channel but not in mutation and heterozygosis channels. CONCLUSION: This study evidenced a functional dominant-negative current suppression in HEK293 cells transfected with HERG mutation A561V.

[Single nucleotide polymorphisms of genes associated with high density lipoprotein metabolism in Chinese population].

OBJECTIVE: To study the single nucleotide polymorphisms in genes associated with the high density lipoprotein (HDL) metabolism in Chinese population. METHODS: Two hundred and nine normal Han ethnic subjects, aged 59+/-10 years, were recruited from 5 medical centers in western part of China. DNA was extracted by proteinase K digestion, phenol and chloroform extraction as well as isopropanol precipitation. The polymerase chain reaction (PCR)-restriction fragment length polymorphisms (RFLP) in conjunction with sequencing were employed to test the single nucleotide polymorphisms (SNPs) in ATP-binding cassette transporter (ABCA1), cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genes. RESULTS: The allelic frequencies of A and G of ABCA1 gene are 53.4% and 46.6%; of B2 and B1 allele of CETP, 41.0% and 59.0%; of HindIII (-) and (+) allele of LPL, 18.9% and 81.1%; and of PvuII(+) and (-) allele of LPL, 66.0% and 34.0%, respectively. All genotype frequencies fit well with the Hardy-Weinberg equilibrium; the significant linkage disequilibrium exists between LPL HindIII(+)and PvuII(+) polymorphisms. All of the RFLP in these genes result from the single nucleic substitution in fragment recognized by corresponding restriction enzymes. CONCLUSION: The genetic polymorphisms of ABCA1, LPL-HindIII and LPL-PvuII in Chinese Han ethnic population are significantly different from Caucasians residing in USA or Europe.

Fractional amplitude of low-frequency fluctuation changes in monkeys with spinal cord injury: a resting-state fMRI study.

PURPOSE: Although functional magnetic resonance imaging (fMRI) has revealed that spinal cord injury (SCI) causes anomalous changes in task-induced brain activation, its effect during the resting state remains unclear. The aim of this study is to explore the changes of the brain resting-state function in non-human primates with unilateral SCI. MATERIALS AND METHODS: Eleven adult female rhesus monkeys were subjected to resting-state fMRI: five with unilateral thoracic SCI and six healthy monkeys, to obtain the fractional amplitude of low-frequency fluctuations (fALFF) of the blood oxygenation level-dependent (BOLD) contrast signal to determine the influence of SCI on the cerebral resting-state function. RESULTS: The SCI-induced fALFF vary significantly in several encephalic regions, including the left cerebellum, the left thalamus, the right lateral geniculate nucleus, the right superior parietal lobule, and the posterior cingulate gyrus. CONCLUSION: Analysis of the resting-state fMRI provides evidence of abnormal spontaneous brain activations in primates with SCI, which may help us understand the pathophysiologic mechanisms underlying the changes in neural plasticity in the central nervous system after SCI.

[Anti-tumor mechanisms of Sp2/0 tumor vaccine transfected with mIL-21 gene in mice].

AIM: To explore the anti-tumor mechanism of Sp2/0-mIL-21 tumor vaccine in mice. METHODS: The molecules of MHC-I and CD80 on the surface of Sp2/0-mIL-21 tumor vaccine were detected by flow cytometry (FCM) respectively. A flow cytometric CFSE-7-AAD cytotoxicity assay was used to detect the cytotoxic activities of NK cells and CTLs. The expression of I-TAC in the tumor tissue was tested by RT-PCR. RESULTS: The expression of MHC-I molecule on the surface of tumor vaccine was up-regulated obviously. The cytotoxic activities of NK cells and CTLs were significantly enhanced in the mice inoculated with Sp2/0-mIL-21 tumor vaccine compared with the mice inoculated with Sp2/0 tumor cell in control group. The expression of I-TAC in the tumor tissue was up-regulated. The histopathologic section analysis showed more lymphocytes were infiltrated in the tumor tissue. CONCLUSION: Sp2/0-mIL-21 tumor vaccine can induce strong cell-mediated immune response to tumor cells after it was inoculated s.c into mice. The anti-tumor mechanisms induced by Sp2/0 tumor cell vaccine are associated with the proliferation and activation of T lymphocyte, the differentiation and maturity of NK cell, the infiltration of lymphocytes in tumor tissue, and the enharuement of cytotoxic activities of NK cells and CTLs.