ABSTRACT
Patch clamp is a technique that can measure weak current in the level of picoampere (pA). It has been widely used for cellular electrophysiological recording in fundamental medical researches, such as membrane potential and ion channel currents recording, etc. In order to obtain accurate measurement results, both the resistance and capacitance of the pipette are required to be compensated. Capacitance compensations are composed of slow and fast capacitance compensation. The slow compensation is determined by the lipid bilayer of cell membrane, and its magnitude usually ranges from a few picofarads (pF) to a few microfarads (μF), depending on the cell size. The fast capacitance is formed by the distributed capacitance of the glass pipette, wires and solution, mostly ranging in a few picofarads. After the pipette sucks the cells in the solution, the positions of the glass pipette and wire have been determined, and only taking once compensation for slow and fast capacitance will meet the recording requirements. However, when the study needs to deal with the temperature characteristics, it is still necessary to make a recognition on the temperature characteristic of the capacitance. We found that the time constant of fast capacitance discharge changed with increasing temperature of bath solution when we studied the photothermal effect on cell membrane by patch clamp. Based on this phenomenon, we proposed an equivalent circuit to calculate the temperature-dependent parameters. Experimental results showed that the fast capacitance increased in a positive rate of 0.04 pF/℃, while the pipette resistance decreased. The fine data analysis demonstrated that the temperature rises of bath solution determined the kinetics of the fast capacitance mainly by changing the inner solution resistance of the glass pipette. This result will provide a good reference for the fine temperature characteristic study related to cellular electrophysiology based on patch clamp technique.
Subject(s)
Cell Membrane , Electric Capacitance , Membrane Potentials , Patch-Clamp Techniques , TemperatureABSTRACT
Objective To study the serum levels of melatonin,tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) in multiple sclerosis (MS) patients and the correlation with disability.Methods Forty patients with multiple sclerosis were collected as MS group and 30 healthy participants were collected as control group.Serum levels of melatonin and cytokines,including IFN-γ and TNF-,were detected in all participants by the enzyme-linked immunosorbent assay (ELISA) method;disability status of patients with MS was evaluated by EDSS scale.The relevant analysis between serum melatonin,TNF-α,IFN-γ levels and EDSS score in patients with MS was conducted.Results The concentration of serum melatonin in MS group was significantly lower than control group (P＜0.01).TNF-α levels were higher than control group (P＜0.05) and the difference was statistically significant between MS patients and control group.Among MS group and control group,no significant correlation with the serum levels of IFN-γ was seen.The serum melatonin level was inversely correlated with EDSS score in MS patients (r =-0.76,P＜0.01),and positively correlated with TNF-α (r =0.83,P＜0.01) and as compared to IFN-γ,no significant correlation was found (r =0.17,P＞0.05).Conclusion The decrease of melatonin and increase of TNF-α can be a factor in the inflammatory reaction in patients with MS,and is closely related with dysfunction occurring in multiple sclerosis.Serum melatonin and TNF-α can be used as laboratory indicators to monitor clinical curative effect and evaluate prognosis of MS.
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Objective To compare the therapeutic effect of video-assisted thoracoscopic surgery and traditional thoracotomy in fixation of traumatic multiple rib fractures.Methods Clinical data of 56 patients with traumatic multiple rib fractures treated surgically between July 2005 and September 2012 were analyzed retrospectively.Based on the treatments,the patients were assigned to video-assisted thoracoscopy group (thoracoscopy group,n =27) and traditional thoracotomy group (thoracotomy group,n =29).A comparison was done on the variables including operation time,intraoperative blood loss,ventilator support rate,duration of mechanical ventilation,length of ICU stay,incidence of lung infections,visual analogue scale (VAS) at day 3 postinjury and mortality between the two groups.Results Operation time [(128.9 ± 21.1) min vs (140.7 ± 24.2) min],ventilator support rate (70％ vs 76％) and mortality (4％ vs 7％) in thoracoscopy group revealed no statistical differences compared with thoracotomy group (P ＞ 0.05),but intraoperative blood loss [(321.1 ± 30.1)ml vs (438.1 ± 43.2)ml],duration of mechanical ventilation [(4.3 ± 2.1) d vs (7.2 ± 1.6) d],length of ICU stay [(5.9 ± 21.1) d vs (8.5 ± 1.7) d],incidence of lung infection (33％ vs 90％),and VAS [(7.0 ± 1.4) points vs (8.3 ± 0.9) points] were significantly reduced in thoracoscopy group than in thoracotomy group (all P ＜ 0.01).Conclusion Video-assisted thoracoscopic surgery is characterized by fewer intraoperative bleeding,shorter duration of mechanical ventilation and ICU stay,and lower lung infection rate during treatment of traumatic multiple rib fractures compared to traditional thoracotomy.
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<p><b>BACKGROUND AND OBJECTIVE</b>Immunocompromised patients with malignant tumor always lack of strong anti-tumor immune response, because the antigenicity of tumor cells is weak, and antigen-presenting cell function is low, so that can not be effectively presenting tumor antigens to the lymphocytes. Therefore, how to effectively induce anti-tumor immune response is the key issue. Through the study on establishing a method to culture dendritic cells (DC) in vitro and to observe the anti-lung cancer immunological effect induced by DC, we provided definite experiment basis for the clinic application of vaccine based on DC.</p><p><b>METHODS</b>Through the experiment we get the soluble antigen polypeptide from lung cancer cells GLC-82 by 3 mol/L potassium chloride. DCs are cultured and obtained from peripheral blood mononuclear cell by GM-CSF, IL-4 and TNF-a. DCs are identified by flow cytometer (FCM) and immunostaining. DCs modified by lung cancer tumor soluble antigen (TSA) and staphylococcal enterotox in A (SEA), DCs modified by TSA or DCs modified by SEA or DCs modified by nothing were cultivated together with T lymphocyte, and the obtained cells are named TSA-SEA-DCL or TSA-DCL or SEA-DCL or DCL as effector cells. The anti-tumor activity of every effector cells against target cells was assayed with MT method. Shape of DCs and effector cells, and the process of killing target cells were observed in microscope.</p><p><b>RESULTS</b>Induced DCs expressed more CD1a, CD80 and HLA-DR, which had typical cell traits such as tree branch. The killing ratio of the TSA-SEA-DCL in vitro to GLC-82 is larger than TSA-DCL, SEA-DCL and DCL, also larger than to K562. When the effector cells cultivate with target cells, we can observe the CTL approach and gather to the cancer cell, induce it necrosis and apoptosis.</p><p><b>CONCLUSION</b>Ripe DCs that have typical characteristic and phenotype could be induced successfully. High potency and relatively specific antilung caner effect can be prepared in virtue ofDC Bacterin Induced by lung caner TSA and SEA.</p>