听神经病的纯音听阈检查结果分析

目的 探讨听神经病纯音听阈(PTT)检查的特征。方法 对48例听神经病患者的PTT检查结果进行分析，并与耳蜗性聋进行对照比较。结果 听神经病的PTT图有上升型、峰型、匙型、W型、倒S型、水平型和缓降型。双耳对称的PTT图有38例，不对称的有10例。听神经病的听阈升高程度呈轻、中度。左右耳听阈升高程度基本一致。低频听阈升高或以低频听阈升高为主的PTT图型占93．75％(90／96耳)。结论 双耳对称或基本对称的低频听阈升高或以低频听阈升高为主是听神经病的重要特征。     

The treatment of hypertension

1 A 'retrospective' of the development of the drug treatment of hypertension is presented from the early days of ganglion blockers to the present time together with a review of the evidence of benefit from treatment.
2 Current issues and debates are summarised including shortfalls in the control of hypertension in populations, difficulties surrounding the measurement of blood pressure, disagreement on the levels of blood pressure to treat, the goal blood pressures to aim at, issues surrounding lifestyle measures such as the low salt diet and low intensity exercise, and treatment with diuretics and with calcium antagonists.
3 A 'perspective' is presented on some avenues for progress in the years ahead. These will include the identification of genetic markers to determine the hypertensive individuals with the greatest risk of death and of cardiovascular complications.     

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.     

Three antidepressants (amitriptyline,dothiepin, fluoxetine), with and without alcohol,compared with placebo on tests of psychomotor ability related to car driving

Eight female volunteers received acute doses of amitriptyline 50 mg (AMI), dothiepin 50 mg (DOT), fluoxetine 40 mg (FLU) or placebo both with and without a ‘social’ dose of alcohol (ALC) equivalent to 0·5 g/kg body weight absolute alcohol. Performance on a variety of tests of psychomotor ability and cognitive function (critical flicker fusion, choice reaction time, tracking, Maddox Wing and simulated car steering) were performed at 1·5 and 4 hours following treatment. AMI and DOT both with and without ALC impaired performance on a range of tests at either or both 1·5 and 4 hours, although the effects of AMI and AMI + ALC were more widespread and severe than those found with either DOT or DOT + ALC. FLU and FLU + ALC showed no evidence of impairment on any test at either the 1·5 or the 4 hours assessments. The results suggest that there are differences between the experimental substances, at the doses used, in their intrinsic potential for impairing aspects of psychomotor performance and cognitive function.     

不同屈光状态的模糊敏感度比较

目的分析不同屈光组模糊阈值之间的差异,探讨模糊阈值在近视发生发展中的可能作用机制。方法38名志愿者参加本实验,正视组15位,等效球镜度为0.50～-0.50D;近视组23位,其中稳定性近视组17位,屈光不正平均为(-4.76±1.40)D,进展性近视组6位,屈光不正平均为(-3.33±1.43)D。受试者在屈光全矫基础上,采用JND标准测量模糊阈值。结果正视组模糊阈值为(0.21±0.06)D,稳定性近视组为(0.27±0.05)D,进展性近视组为(0.33±0.06)D。近视组的模糊阈值高于正视组(P=0.001),近视组中,进展性近视组的模糊阈值高于稳定性近视组(P=0.028)。结论近视对模糊的敏感度下降,其中进展性近视的敏感度下降更显著,这可能是近视调节滞后增加的部分原因。     

The Cardiac Pacemaker Current if

Pacemaker Current if. Since the hyperpolarization-activated current, if, was originally associated with the diastolic depolarization phase of action potential in the sinoatrial (SA) node in 1979, its central role in the generation and control of pacemaker activity has become increasingly clear through a series of experimental findings, some of which have substantially modified the pre-existing theories of cardiac pacemaking and its modulation by the autonomic transmitters. Thus, the pacemaker current of Purkinje fibers, formerly described as a deactivating pure potassium (K) current, was found to be in fact, like the nodal if, inward and activating on hyperpolarization. Furthermore, in SA node cells, as well as mediating rhythm acceleration induced by catecholamines, if was found to underlie the slowing effect of low acetylcholine (ACh) concentrations, in contrast with the generally accepted hypothesis that activation of a K conductance is the main process responsible for cardiac slowing. A final, atypical property of if recently demonstrated concerns the activating action exerted on if by intracellular cAMP. Unlike that on other voltage-gated, cAMP-modulated cardiac channels, this action is independent of phosphorylation and involves a direct binding of cAMP to if channels. (J Cardiovasc Electrophysiol, Vol. 3, pp. 334–344, August 1992)     

老年黄斑变性的视网膜色素上皮及其视功能的改变

目的：应用黄斑区密集点矩阵视野并结合眼底荧光血管造影电脑眼底图像分析老年黄斑变性视网膜色素上皮损害与ＤＭＭＭ的视野光敏感度的改变，找出改变的规律有评价其应用价值。方法：用Ｈｕｍｐｈｒｅｙ－６４０视野计自行设计ＤＭＭＭ检测ＡＭＤ干性组５１人６４只眼湿性且２３人２７只眼，用Ｚｅｉｓｓ公司生产的ＫＯＮＴＲＯＮＥＬＥＫＴＲＯＮＩＫ Ｉｎａｇｅ Ａｎａｌｙｓｉｓ Ｄｉｖｉｓｉｏｎ－计算机图像分析仪总丢失量显     

大型Tokamak装置中环向场超导线圈的传热研究

分析了HT-7U超导Tokamak核聚变装置中环向场超导线圈上的涡流损耗热产生的机理和迫流式超临界氦对流换热等过程，特别针对等离子体快速破裂时，极短时间内在环向场磁体中所产生的较大的涡流损耗而引起的焦耳热，对环向场线圈盒与超导磁体之间的热传递过程加以研究。本文采用国际上通用的有限元分析软件ANSYS5.7进行计算，计算所得的结果较为乐观。