Sodium renal imaging in mice at high magnetic fields.

This work presents the first sodium MRI functional renal study on a mouse model. The tissue sodium concentration was monitored during induced diuresis with furosemide. By using density-weighted chemical shift imaging (DWCSI) at high field strength a temporal resolution of less than 5 min for three dimensional (3D) data sets with high spatial resolution was achieved. A maximum increase of 20% in the cortex and a decrease of 45% of the original signal strength in the medulla were observed. These findings correspond well with experiments conducted on much larger rodent models.     

透明质酸钠预防粘连性肠梗阻术后再粘连临床观察

Objective To investigate the prevention of intestines adhesion about sodium hyaluronic acid in postoperative intestines adhesion.Methods Eighteen cases of adhesive intestine obstruction were done intestinal release or bowel resection.2～4mL sodium hyaluronic acid was put to the wound,anastigmatic and rough surface of peritoneal.Gastrointestinal decompression,anti-infective and infusion were taken after oper-ations.Followed up 8～24 months.Results Obstructive symptoms haven't happened,the effective rate is 100%.Only 2 cases have intermittent abdominal pain without obstruction,the incidence was 11%.Conclu-sion Sodium hylauronic acid is effective to prevent the adhesion of postoperative intestines adhesion,simp-ler use,fewer side-effects and great value to appliance.     

高容血液稀释联合术中控制性降压对腰椎手术病人心率变异性的影响

目的:探讨术前急性高容血液稀释联合术中硝普钠控制性降压对腰椎手术病人心率变异性(HRV)的影响.方法:15例腰椎骨折椎板减压、切复内固定病人,术前输入6%羟乙基淀粉20ml/kg和乳酸林格氏液20ml/kg以实施急性高容血液稀释,术中采用硝普钠微泵输注实施控制性降压,输注速度为0.5～6μg·kg-1·min-1,控制平均压(MAP)在55～65mmHg之间.观察插管后稀释前(T0)、稀释后降压前(T1)、降压后10min(T2)、30min(T3)和停降压后10min(T4)和30min(T5)6个时间点总功率谱(TP)、低频值(LF)、高频值(HF)、LF/HF、标化低频值(Lfnrom)和标化高频值(Hfnorm).结果:以上6个时间点TP、LF、HF、LF/HF、Lfnrom和Hfnorm均无显著变化.结论:术前急性高容血液稀释联合术中控制性降压时心脏自主神经功能稳定.     

AN-132 block of cardiac sodium channels: A gate-related receptor analysis

Summary Based on the gate-related receptor hypothesis, an analysis of kinetics of AN-132, a new antiarrhythmic agent, blockade of cardiac sodium channels and the gate-related receptor which is bound by the drug was performed by computer simulation. Model-predicted apparent rates of onset of AN-132 (30 μmol/L) blocking were 0.051, 0.038, and 0.034 AF⁻¹ at stimulation frequencies of 1.0, 2.0 and 3.0 Hz, respectively. The time constant of recovery from block by AN-132 at resting potential -90 mV was 39.5 s. These findings are in agreement with those experimental data documented. The analysis of gate-related receptor shows that AN-132 binds the inactivation gate-related receptor, and the binding and unbinding are modulated by the inactivation process.     

Differential effects of the pyrethroid tetramethrin on tetrodotoxin-sensitive and tetrodotoxin-resistant single sodium channels

The differential effects of the pyrethroid tetramethrin on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) single sodium channel currents in rat dorsal root ganglion (DRG) neurons were investigated using the outside-out configuration of patch-clamp technique. Channel conductances were 10.7 and 6.3 pS for TTX-S and TTX-R sodium channels, respectively, at a room temperature of 24–26°C. The single-channel current of TTX-S sodium channels at the test potential of −30 mV was −1.27 ± 0.25 pA, and was not changed after exposure to 10 μM tetramethrin (−1.28 ± 0.23 pA). The open time histogram of TTX-S single-channel currents could be fitted by a single exponential function with a time constant of 1.27 ms. After exposure to 10 μM tetramethrin, the open time histogram could be fitted by the sum of two exponential functions with time constants of 1.36 ms (τ_fast) and 5.73 ms (τ_low). The percentage of contribution of each component to the population was 62% for the fast component representing the normal channels and 38% for the slow component representing the tetramethrin modified channels. The amplitudc of TTX-R single-channel currents was slightly changed from −0.72 ± 0.14 to −0.83 ± 0.07 pA by 10 μM tetramethrin. The open time histogram of TTX-R single-channel currents could be fitted by a single exponential function with a time constant of 1.92 ms. In the presence of 10 μM tetramethrin, the open time histogram could be fitted by the sum of two exponential functions with time constants of 2.07 ms (τ_fast) and 9.75 ms (τ_slow). The percentage of contribution of each component was 15% for the fast, unmodified component and 85% for the slow, modified component. Differential effects of tetramethrin on the open time distribution of single sodium channel currents explains the differential sensitivity of TTX-S and TTX-R sodium channels.     

抑制剂对酪氨酸酶影响的初步研究

采用酶动力学及聚丙烯酰胺凝胶电泳方法研究了ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ、ＤＤＣ对酪氨酸酶的抑制作用。ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ为非竞争性抑制作用，随着抑制剂浓度增加，酶活性逐渐减弱。当ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ的浓度分别达到１．２ｍｍｏｌ／Ｌ１２。５ｍｍｏｌ／Ｌ１２．５ｍｍｏｌ／Ｌ时，酶活性的抑制率为１００％、５０％、２４％。ＤＤＣ对酪氨酸酶的抑制作用为竞争性抑制作用，其浓度达４ｍｍｏｌ／Ｌ时，酶活性１００％受到抑制。     

高危出血患者应用吉派林抗凝血液透析疗效观察

目的：观察危重型肾功能衰竭合并高危出血患者选择抗凝药物进行血液透析治疗的效果。方法：应用吉派林(低分子肝素钠)作为抗凝剂进行血液透析。结果：129例病人进行血液透析386次，均没有出血发生。结论：吉派林在高危出血患者血液透析中使用方便，安全，效果良好。     

头孢哌酮钠在醋酸钠平衡液中的稳定性

考察了头孢哌酮钠在醋酸钠平衡液中的稳定性。二药配伍后，置室温（２５℃）及３７℃水浴中，６ｈ内溶液无颜色改变，亦无沉淀、气体产生，头孢哌酮钠均在初始浓度的９５％以上。     

Effects of acetylsalicylic acid on electromechanical activity ofin vivo rabbit ileum

Aspirin has antisecretory and ulcerogenic properties in the gastrointestinal tract. The aim of this study was to determine the effects of acetylsalicylic acid (ASA) on the electrical and mechanical activity of the ileum in anesthetized New Zealand White rabbits. Ileal electromechanical activity was recorded from serosal electrodes and a miniature intraluminal balloon. Thirty minutes after injection of ASA (30, 60 and 100 mg/kg intravenous) significant and dose-dependent increases in the percentage of slow waves with action potentials were observed when compared with saline-injected animals. The onset of action potentials correlated with phasic increases in intraluminal pressure, indicating the onset of circular muscle contractions. Injection of 15 mg/kg ASA, sodium salicylate (100 mg/kg intravenous) or saline had no effect on baseline action potential activity. Prostaglandin E ₂ (PGE ₂)(5 and 10 g/kg intravenous) significantly increased slow-wave frequency and decreased ASA-induced action potential activity. This study demonstrates that (1) ASA, but not sodium salicylate, stimulates phasic ileal action potential and contractile activity and (2) in ASA-treated animals, PGE ₂ produces differential effects on in vivoslow-wave frequency and action potential activity.     

Subthreshold oscillations generated by TTX-sensitive sodium currents in dorsal cochlear nucleus pyramidal cells

During intracellular recordings in rodent brainstem slice preparations, dorsal cochlear nucleus (DCN) pyramidal cells (PCs) exhibit characteristic discharge patterns to depolarizing current injection that depend on the membrane potential from which the responses are evoked. When depolarized from hyperpolarized potentials, PCs can respond with a short-latency action potential followed by a long silent interval (pauser) or a train of action potentials with a long latency (buildup). During the silent intervals in a pauser or a buildup response, the membrane potential slowly depolarizes towards spike threshold, often exhibiting distinct voltage oscillations of 1–2 mV before the first spike. The subthreshold voltage oscillations were investigated using whole cell recordings from DCN PCs in rat pup (P10–14) brainstem slices. The oscillations were unaffected by excitatory and inhibitory neurotransmitter antagonists, and were not temporally locked to the onset of the depolarization. The oscillations typically became larger as spike threshold was approached, and had a characteristic frequency between 40 and 100 Hz. In the presence of tetrodotoxin (TTX, 500 nM), the oscillations were significantly suppressed, and could not be evoked at any voltage below or above spike threshold. The oscillations were not blocked by phenytoin or Cd²⁺, but they were affected by prior activity in the neuron for approximately 1 s. We conclude that voltage-gated Na⁺ channels are required to generate membrane oscillations during the buildup phase. We suggest that the subthreshold oscillations play a role in controlling spike timing in PCs when the membrane potential slowly approaches, or hovers near, spike threshold.