[Regulatory effect of the pannexin1 channel on invasion and migration of testicular cancer Tcam-2 cells and its possible mechanism].

OBJECTIVE: To investigate the role of the pannexin-1 (Panx1) protein in the invasion and migration of testicular cancer Tcam-2 cells and its possible action mechanism. METHODS: Tcam-2 cells were treated with carbenoxolone (CBX) at 100 µmol/L and probenecid (PBN) 200 µmol/L. Then the intercellular fluorescence transmission was assessed by real-time fluorescence assay, the extracellular ATP concentration measured by chemi-luminescence immunoassay, the invasive and migratory abilities of the Tcam-2 cells detected by Transwell assay, and the expressions of the proteins Panx1, p-ERK1/2, ERK1/2, vimentin, MMP-9 and E-cadherin in the TM3 Leydig cells and testicular cancer Tcam-2 cells determined by Western blot. RESULTS: Western blot showed that the expression of the Panx1 protein was significantly higher in the testicular cancer Tcam-2 cells than in the TM3 Leydig cells (2.79 ± 0.17 vs 1.00 ± 0.06, P<0.05). The rates of intercellular fluorescence transmission in the Tcam-2 cells treated with CBX and PBN were markedly decreased as compared with the blank control group (ï¼»61.54 ± 3.30ï¼½% and ï¼»68.06 ± 4.03ï¼½% vs ï¼»99.50 ± 3.12ï¼½%, P<0.01), and so were the extracellular ATP concentrations (ï¼»57.06 ± 5.80ï¼½% and ï¼»56.42 ± 7.70ï¼½% vs ï¼»110 ± 8.16ï¼½%, P<0.01). The numbers of migrated Tcam-2 cells in the CBX and PBN groups were significantly reduced in comparison with that in the control (11.5 ± 1.11 and 8.25 ± 1.23 vs 331.00 ± 30.80, P<0.05), and so were those of the invaded ones (11.75 ± 3.77 and 11.5 ± 3.5 vs 89.00 ± 13.09, P<0.01). CBX and PBN significantly down-regulated the expression of p-ERK1/2 as compared with that in the blank control group (0.538 ± 0.05 and 0.476 ± 0.02 vs 0.98 ± 0.03, P<0.05), as well as those of vimentin (0.541 ± 0.09 and 0.705 ± 0.07, P<0.01) and MMP-9 (0.439 ± 0.08 and 0.557 ± 0.065, P<0.01) but up-regulated that of E-cadherin (3.896 ± 0.06 and 3.551 ± 0.04, P<0.01). CONCLUSIONS: The Panx1 protein is highly expressed in testicular cancer Tcam-2 cells. CBX and PBN can inhibit the function of the panneixn1 channel and reduce the invasive and migratory abilities of the Tcam-2 cells, which is associated with the decreased expression of the p-ERK1/2 protein.

[Effect of acupuncture pretreatment on action potential of cerebellar Purkenje cells in ex vivo ischemic rat brain slices].

OBJECTIVE: To investigate the effect of acupuncture pretreatment at specific acupoints on action potential of cerebellar Purkenje cells in rats early after cerebral ischemia. METHODS: Forty male SD rats were randomized into control group, ischemia group, acupuncture pretreatment group and acupuncture pretreatment plus ischemia group. The rats in acupuncture groups received acupuncture pretreatment at Baihui and bilateral Zusanli twice daily for 7 consecutive days, after which brain slices were prepared and perfused at a lowered rate to simulate in vivo ischemic stroke. Microelectrode and whole cell current clamp technique were used for recording the action potentials of cerebellar Purkenje cells to detect changes in spike encoding of the cells. RESULTS: Compared with those in the control group, the rat brain slices early after simulated ischemia showed significantly shortened inter-spike intervals, increased standard deviation of spike timing and decreased voltage of threshold potentials (P<0.01), suggesting overexcitation of the Purkinje cells. Acupuncture pretreatment at Baihui and bilateral Zusanli obviously suppressed overexcitation of the Purkinje cells in response to ischemia. CONCLUSION: Acupuncture pretreatment at Baihui and bilateral Zusanli can improve ischemic stroke by suppressing overexcitation of Purkenje cells in rats.

[Influence of Acidosis on Electrophysiological Characteristics of Cortical GABAergic Neurons in Mice].

OBJECTIVE: To investigate the influences of extracellular acidosis on spike encoding and synaptic transmission of cortical GABAergic neurons in mice. METHODS: Twenty mice aged 27-30 d mice were selected to prepare coronary cortical slices and then divided into control group and extracellular acidosis group. In control group,the coronal slices were perfused with artificial cerebrospinal fluid at pH7.4,the action potential threshold potential,absolute refractory period and action potential peak spacing were recorded with the patch-clamp all-cell current clamp mode; the spontaneous excitatory postsynaptic current was recorded with the voltage clamp mode extracellular acidosis group,the artificial cerebrospinal fluid was adjusted at pH6.5,mimicking extracellular acidosis. Recorded neurons action potential and spontaneous excitatory postsynaptic currents again,comparing the difference of the above indexes between the two groups. RESULTS: Compared with the control group,the extracellular acidosis significantly prolonged the inter-spike intervals and absolute refractory periods (P<0.01),increased the voltage of threshold potentials and the amplitude and frequency of spontaneous excitatory postsynaptic currents (P<0.01). CONCLUSION: Extracellular acidosis leads to the dysfunction of cortical GABAergic neurons by breaking the inter-characteristics and synaptic transmission,contributing one of the possible mechanisms to acidosis-induced brain damage.

Dual face of axonal inhibitory inputs in the modulation of neuronal excitability in cortical pyramidal neurons.

Limited by the tiny structure of axons, the effects of these axonal hyperpolarizing inputs on neuronal activity have not been directly elucidated. Here, we imitated these processes by simultaneously recording the activities of the somas and proximal axons of cortical pyramidal neurons. We found that spikes and subthreshold potentials propagate between somas and axons with high fidelity. Furthermore, inhibitory inputs on axons have opposite effects on neuronal activity according to their temporal integration with upstream signals. Concurrent with somatic depolarization, inhibitory inputs on axons decrease neuronal excitability and impede spike generation. In addition, following action potentials, inhibitory inputs on an axon increase neuronal spike capacity and improve spike precision. These results indicate that inhibitory inputs on proximal axons have dual regulatory functions in neuronal activity (suppression or facilitation) according to neuronal network patterns.

Diagnostic Accuracy of Natriuretic Peptides for Heart Failure in Patients with Pleural Effusion: A Systematic Review and Updated Meta-Analysis.

BACKGROUND: Previous studies have reported that natriuretic peptides in the blood and pleural fluid (PF) are effective diagnostic markers for heart failure (HF). These natriuretic peptides include N-terminal pro-brain natriuretic peptide (NT-proBNP), brain natriuretic peptide (BNP), and midregion pro-atrial natriuretic peptide (MR-proANP). This systematic review and meta-analysis evaluates the diagnostic accuracy of blood and PF natriuretic peptides for HF in patients with pleural effusion. METHODS: PubMed and EMBASE databases were searched to identify articles published in English that investigated the diagnostic accuracy of BNP, NT-proBNP, and MR-proANP for HF. The last search was performed on 9 October 2014. The quality of the eligible studies was assessed using the revised Quality Assessment of Diagnostic Accuracy Studies tool. The diagnostic performance characteristics (sensitivity, specificity, and other measures of accuracy) were pooled and examined using a bivariate model. RESULTS: In total, 14 studies were included in the meta-analysis, including 12 studies reporting the diagnostic accuracy of PF NT-proBNP and 4 studies evaluating blood NT-proBNP. The summary estimates of PF NT-proBNP for HF had a diagnostic sensitivity of 0.94 (95% confidence interval [CI]: 0.90-0.96), specificity of 0.91 (95% CI: 0.86-0.95), positive likelihood ratio of 10.9 (95% CI: 6.4-18.6), negative likelihood ratio of 0.07 (95% CI: 0.04-0.12), and diagnostic odds ratio of 157 (95% CI: 57-430). The overall sensitivity of blood NT-proBNP for diagnosis of HF was 0.92 (95% CI: 0.86-0.95), with a specificity of 0.88 (95% CI: 0.77-0.94), positive likelihood ratio of 7.8 (95% CI: 3.7-16.3), negative likelihood ratio of 0.10 (95% CI: 0.06-0.16), and diagnostic odds ratio of 81 (95% CI: 27-241). The diagnostic accuracy of PF MR-proANP and blood and PF BNP was not analyzed due to the small number of related studies. CONCLUSIONS: BNP, NT-proBNP, and MR-proANP, either in blood or PF, are effective tools for diagnosis of HF. Additional studies are needed to rigorously evaluate the diagnostic accuracy of PF and blood MR-proANP and BNP for the diagnosis of HF.

Direct comparison of the diagnostic accuracy between blood and cerebrospinal fluid procalcitonin levels in patients with meningitis.

OBJECTIVE: To compare the clinical utility of serum and cerebrospinal fluid (CSF) procalcitonin (PCT) for the diagnosis of bacterial meningitis (BM) among patients with suspected meningitis. METHODS: Patients with meningitis-like symptoms (n=120), admitted to the Second People's Hospital of Wuxi or the Changhai Hospital of Shanghai between January 2011 and December 2013, were prospectively and consecutively enrolled in this study. BM was finally diagnosed by CSF culture, Gram staining, quantitative polymerase chain reaction (qPCR), and treatment response. The diagnostic accuracy of the serum and CSF PCT was assessed by receiver operator characteristic (ROC) curve analysis. The relationship between CSF and serum PCT levels as well as the CSF leukocyte count and protein level was analyzed by Spearman's correlation analysis. RESULTS: PCT level in both the serum and CSF was significantly increased in the BM patients. The area under ROC curve of serum PCT for the diagnosis of BM was 0.96 (95% confidence interval (CI): 0.93-1.00), significantly higher than that of CSF PCT (0.90, 95% CI: 0.83-0.96). Using 0.88ng/mL as the threshold, the diagnostic sensitivity, specificity, and accuracy of serum PCT for the diagnosis of BM were 0.87 (95% CI, 0.73-0.95), 1.00 (95% CI, 0.95-1.00), and 95%, respectively. The serum PCT level was positively correlated with the CSF PCT level, leukocyte count, and protein level. CONCLUSION: Both the serum and CSF PCT had a high diagnostic value for BM among suspected meningitis patients, and serum PCT demonstrated a superior diagnostic value compared to CSF PCT.