MR imaging of viscoelastic properties

Mechanical waves in magnetic resonance imaging, which have been suggested for possible clinical applications, were analyzed with regard to imaging of the viscoelastic properties of large objects. The method is based on the Larmor frequency modulation caused by the application of mechanical waves. Possible clinical applications include all diseases that result in a change in the mechanical properties of biologic tissues (eg, atherosclerosis).     

OODG-Ulrich and OPG-Gee: a comparative study

For an adequate assessment of both the ophthalmological and the neurological consequences of carotid obstruction measurement of the blood pressure in the carotid flow area is essential.To this end there are two objective, registrating methods available at the moment: OPG-Gee and OODG-Ulrich. A comparative study was made into the basic principles, calibration curves and application methods of these systems. By both methods the systolic retinal - and ciliary - as well as the diastolic ocular blood pressure can be measured. OODG is more exact for the differentiation and measurement of the two systolic blood pressures. OPG-Gee, however, offers the unique additional possibility of a judgement on the systolic blood pressure in the carotid siphon without, however, taking into acount a (difference in) pre-existing intraocular pressure. Our own investigation shows that in order to obtain a correct assessment of the carotico-brachial relation both blood pressures should be measured simultaneously. The results of the graphic analysis of the curves are compared to those by Ulrich. For the diagnosis of carotid obstructions this analysis of the shape had no advantages over the determination of the pressure values.Finally, a survey is given of possible applications of OPG and OODG in various other syndromes.     

Dose-response differences in the ability of ramipril to improve retention in diabetic mice

Ramipril blocks the conversion of angiotensin I to II. The literature indicates that diabetes is often associated with mild impairment of learning and memory. The study reports the effects of ramipril on memory retention in diabetic and non-diabetic mice. Mice were made diabetic by an injection of streptozocin. After overt signs of diabetes were present, diabetic or vehicle-treated mice were partially trained on a footshock active avoidance task. Immediately after training, ramipril (0.5–1.5 mg/kg s.c.) was administered and retention was tested by continuing training one week later until mice avoided footshock on five out of six trails. The results indicate that ramipril enhanced retention of both diabetic and control mice but it required about 5 times as much ramipril in diabetic as control mice to achieve the same effect on retention. Increased sensitivity to angiotensin II may play a role in cognitive impairment in diabetes.     

头低位模拟失重状态对前庭功能的影响

为研究头低位模拟失重对运动病症状、垂直视动眼震（ＶＯＫＮ）及体液重新分配的影响，在头低位－１０°的模拟失重状态下，采用大视野的垂直视动刺激，观察１８名正常人的运动病症状、ＶＯＫＮ、激素（ＡＶＰ、ＶＩＰ、ＣＯＲＴ、ＡＬＤＯ）的反应特点。结果表明，头低位－１０°状态下的大视野垂直视动刺激可以诱发出明显的运动病症状，头低位－１０°的垂直视动刺激比坐位更容易诱发运动病。坐位状态ＶＯＫＮ慢相速度有明显的方向性不对称，敏感组ＶＯＫＮ方向性不对称有显著差异（Ｐ＜０．０５）。头低位－１０°时ＶＯＫＮ的不对称现象不明显，向下方向运动的ＶＯＫＮ慢相速度显著增加。分析指出，头低位－１０°状态下垂直视动刺激比坐位和秋千刺激的贡献率大。尿中ＣＯＲＴ（皮质醇）在秋千和头低位的垂直视动刺激前后有显著性增加。提示：大视野的垂直视动刺激与头低位－１０°两种刺激的结合可能成为预测空间运动病的方法之一．     

毛细管区带电泳法测定复方马来酸依那普利片中两组分含量

用毛细管区带电泳法同时测定复方马来酸依那普利片中两组分含量。以咖啡因为内标，２０ｍｍｏｌ／Ｌ硼砂—２０ｍｍｏｌ／Ｌ磷酸二氢钠（４９∶５１，ｐＨ８６）为运行缓冲液，在７ｍｉｎ内完成分离。马来酸依那普利和氢氯噻嗪的线性范围分别为８０～６４０μｇ／ｍＬ（ｒ＝０９９９９）和５０～４００μｇ／ｍＬ（ｒ＝０９９９３）。平均回收率分别为１０１０％和１０１１％，ＲＳＤ分别为１０％和１７％，ｎ＝５。     

通塞益脑液治疗急性脑梗塞的机理探讨

本文以结扎左侧颈总动脉造成实验性急性脑梗塞的沙土鼠模型,探讨通塞益脑液治疗急性脑梗塞的机理。发现结扎术前胃饲通塞益脑液者,可降低急性脑梗塞后脑组织中过氧化脂质的含量;结扎术后给药者,可降低脑组织中钙的含量。初步认为通塞益脑液对急性脑梗塞的脑组织有保护作用。     

A comparison of the effects of scopolamine and diazepam on acquisition and retention of inhibitory avoidance in mice

Administration of either the muscarinic antagonist scopolamine or the benzodiazepine diazepam prior to training produced a dose-dependent impairment in the retention of one-trial inhibitory avoidance training in mice. To investigate the nature of this drug effect, the effects of scopolamine and diazepam were subsequently assessed on both acquisition and retention of inhibitory avoidance using a multiple-trial, training-to-criterion procedure. The training was conducted using either continuous trials in which the mouse was free to shuttle back and forth between shock and safe compartments or discrete trials in which the mouse was moved from the shock compartment of the safe compartment at the start of each trial. In either case, training continued until the mouse refrained from crossing into the shock compartment for a specified length of time on a single trial. Scopolamine (1.0 mg/kg) administered before training significantly increased the number of trials required to attain criterion, but did not affect retention when these mice were tested 2, 16, or 28 days later. In contrast, diazepam (1.0 mg/kg) did not significantly alter the number of trials necessary to reach criterion, but impaired retention of the inhibitory response in mice trained using discrete trials. The differences in the amnestic effects of scopolamine and diazepam revealed by this detailed analysis suggest that diazepam does not impair inhibitory avoidance performance through an effect on cholinergic function.     

Cardioprotection by nisoldipine: role of timing of administration

Nisoldipine was administered at 10^–9M, a dose lackingnegative inotropism, to isolated and perfused rabbit heartssubmitted to 60 min ischaemia (1 ml.min^–1) followed by30 min reperfusion. The drug was delivered either 30 min beforeischaemia, at the onset and after 30 min of ischaemia and duringreperfusion only. Cardiac protection was evaluated in termsof recovery of left ventricular pressure during reperfusion,release of creatine phosphokinase (CPK), mitochondrial function,tissue content of adenosine triphosphate (ATP) and creatinephosphate (CP), calcium homeostasis and the occurrence of oxidativestress, established measuring content and release of reducedand oxidized glutathione. The cytoprotective action of nisoldipine occurs in the absenceof negative inotropism and is closely related to the time ofadministration. Optimal myocardial preservation is achievedwhen nisoldipine is given before or at the onset of ischaemia.Prophylactic administration of nisoldipine improved the recoveryof the developed pressure from 159±10 (SE) mmHg to 478±19mmHg, P<0.01 and reduced the release of CPK from 830±29to 229±27 mU. min^–1 g^–1 wet wt, P<0.01.The accumulation of tissue and mitochondrial calcium was reducedfrom58±11 and49±9 to 14±6 and 10±4 mmol.kg^–1 dry wt respectively, P<0.01. This resulted ina signficant (P<0.01) preservation of all indices of mitochondrialfunction, allowing a higher recovery of ATP and CP after reperfusion(from 4.1±0.7 and 10.0±0.6 to 16.1±1.0and 29.9±0.2 µmol.g^–1 dry wt respectively,P<0.001). Reperfusion-induced myocardial accumulation and release of oxidizedglutathione were reduced from 0.493±0.07 nmol.mg^–1protein and 0.768±0.063 nmol.min^–1g^–1 wetwt to 0.225±0.07 and 0.157±0.038 respectively,P<0.01. Similar data were obtained when nisoldipine was givenat the time of ischaemia, while administration 30 min afterthe onset of ischaemia showed only a trend towards protection.Nisoldipine lost its protective effect when given on reperfusion. A multifactorial analysis of the data suggest that the cardioprotectiveeffect of nisoldipine is related to the maintenance of membraneintegrity, possibly since nisoldipine is highly lipophilic.     

Effects of amino acids on the excitability of respiratory bulbospinal neurons in solitary and para-ambigual regions of medulla in cat

The effects of inhibitory (gamma-aminobutyric acid (GABA) and glycine) and excitatory (L-glutamate and DL-homocysteate, DLH) amino acids on the excitability of respiratory bulbospinal neurons were studied in decerebrate, paralyzed, bilaterally vagotomized, artificially ventilated cats. Unit activities were recorded extracellularly in the medulla in both the ventrolateral portion of the nucleus tractus solitarius and the para-ambigual region in the vicinity of the nucleus ambiguus (dorsal and ventral respiratory groups, respectively). All neurons were bulbospinal since they could be antidromically activated by electrical stimuli to the spinal cord. We used variations in antidromic latency (ADL) as a measure of changes in excitability of the soma. All neurons exhibited variations in ADL related to the respiratory cycle, being shortest (minimum ADL) during neural activity and longest (maximum ADL) in the silent period. Neurons whose discharge frequencies fell during application of putative inhibitory amino acids showed an increase of minimum ADL compared to control, indicating hyperpolarization. Minimum ADL, in some cells, became shorter during application of excitatory amino acids, indicating depolarization; in others, mechanisms secondary to increased neuronal firing likely obscured their effects. The transient maximum ADL usually present at the onset of the silent period was increased by excitatory amino acids and, in some units, was reduced or eliminated by inhibitory amino acids. These effects are discussed in terms of a modulation by synaptic inputs and neurotransmitters of the cumulative afterhyperpolarization which follows bursts of action potentials.     

蝮蛇抗栓酶对老年冠心病患者血液流变学的影响

用蝮蛇抗检酶治疗老年冠心病50例．通过对治疗前后血液流变学变化的观察，了解到蝮蛇抗栓酶能有效改善血浓浓粘聚状态，降低纤维蛋白原，是治疗冠心病的理想药物．