Evaluation of non-invasive techniques to assess vasoconstriction in healthy volunteers using methoxamine as a probe drug

Non-invasive methods for assessment of the vascular effects of antimigraine drugs were evaluated with respect to their utility, variability and sensitivity in a double-blind, placebo-controlled, three-period crossover study in six healthy volunteers using an intravenous vasoconstrictor, methoxamine, as a probe drug. Changes in the internal diameter of the brachial and radial arteries were measured using ultrasound which had low between-day and within-day coefficients of variation. Peak systolic velocity (PSV), time-averaged velocity (TAV), total flow, resistance (RI) and pulsatility indices (PI) were measured by Doppler from one arterial wave form. Whilst PSV and TAV increased with methoxamine, because of bradycardia, changes in PI and RI were difficult to interpret. An automatic oscillametric cuff, a mercury-in-silastic strain gauge method and the "Finapres", finger arterial blood pressure monitor were used to follow changes in systolic blood pressure (SBP). The strain gauge technique underestimated arm SBP compared to the oscillometric method but clearly showed drug-related increases whilst the Finapres did not reflect changes in blood pressure detected by the other methods.     

Inhibition of cyclic nucleotide accumulation following hippocampal tetanic potentiation: Effects of diazepam

Biochemical studies on the hippocampus of acutely prepared rabbits revealed more than two fold increases in cyclic GMP levels following tetanic potentiation of the pathway from the medial septal region to CA₁ pyramidal cells. Diazepam, administered intravenously, prevented the elevation in cyclic GMP levels in this region and also attenuated the post-tetanic potentiation seen following the presentation of trains at frequencies within theta rhythm. The results imply a modulatory role for cyclic nucleotides in the enhancement of pyramidal cell excitability and suggest that the biochemical mechanism for the psychoactive benzodiazepines may well include the suppression of cyclic GMP levels.     

五味子中联苯环辛二烯木脂素类化合物的质谱研究

本文通过低分辨和高分辨质谱和亚稳分析,对五味子甲素(schisandrin A,1)等23个从五味子科(Schisandraceae)植物中分离出的联苯环辛二烯木脂素类化合物进行了质谱裂解方式研究,总结了重要的质谱特征,为今后继续研究五味子科植物及类似新化合物的结构测定提供了可靠依据。     

Practical and technical considerations in establishing an intraoperative radiation therapy program in the community practice

The Radiation Oncology Center in Sacramento, California, has developed a procedure for establishing an intraoperative radiation therapy facility in a community practice. The logistics pertaining to personnel, equipment, physical measurements, and quality assurance are presented. Particular emphasis is given to the most effective means of acquiring the large quantity of data needed to ensure a program of acceptable quality.     

Hyperlipidemia, hypercoagulability, and accelerated thrombosis: studies in congenitally hyperlipidemic rats and in rats and monkeys with induced hyperlipidemia

Inbred Carworth Farms Nelson (CFN) congenitally hyperlipidemic rats had significantly shorter coagulation and prothrombin times and higher levels of coagulation factors, II, V, VII, VIII, and X than did controls. Conversely, congenitally hypolipidemic rats of the same strain had significantly longer coagulation and prothrombin times and lower levels of factors II, V, VII, X and XII and of blood platelets than did controls. A loop-shaped polyethylene cannula was inserted into the aorta to assess the potential for thrombosis. The hyperlipidemic group obstructed this significantly faster and the hypolipidemic group slower than did the controls. Normal CFN rats made hypertensive by unilateral renal artery clip developed hypertension together with significantly elevated serum cholesterol and factor VII and X levels. Rhesus monkeys with diet-induced hyperlipidemia showed shorter prothrombin times and higher factor X levels than did controls on normal diet. By selective breeding, two groups of squirrel monkeys were obtained. Both groups had similar serum cholesterol levels on a normal diet but one group (hyperresponders) showed higher serum cholesterol levels on a cholesterol-containing diet than did the other (hyporesponder) group. Both groups showed significantly elevated levels of factors II, V, VII, IX and X on a cholesterol-containing diet. There was good correlation between the levels of many coagulation factors and serum cholesterol in both rats and monkeys. If thrombosis is important in the genesis of atherosclerosis, these findings could indicate that elevation of plasma lipids may play a role, via the coagulation pathway, in the production of human vascular disease.     

Electrographic changes in the amygdala and hippocampus associated with biting attack

Squirrel monkeys had chronic electrodes implanted in various brain structures known to be involved in aggression. Changes in the electrical activity of these regions were monitored in sessions where the animals were restrained and biting either a pneumatic hose or food. It was found that whereas eating behavior was not consitently associated with desynchronization of the basolateral and corticomedial division of the amygdala and the hippocampus, hose-biting was associated with concurrent shifts from synchronization to desynchronization in these regions. The present findings are consistent with the interpretation of amygdaloid function as being that of a modulator of anatomically related regions. The data further suggest that portions of the amygdala are preferentially activated by aversive environmental conditions, and that such activation is functionally related to the occurrence of aggressive behavior.     

Electrophysiological studies of the septal nuclei. II. The medial septal region.

The medial septal region was found to have two distinct zones: the medial septal nucleus and the nucleus of the diagonal band of Broca. The medial septal nucleus projects out of the septal region in both dorsal and ventral directions. This, together with short durations of response suppression, gives this region the appearance of a relay center. The nucleus of the diagonal band of Broca also projects out in both dorsal and ventral directions. But, in contrast to the medial nucleus, the durations of test response suppression were highly variable. Therefore, in addition to performing relay-like functions, the nucleus of the diagonal band gives the impression of being capable of “higher” orders of integration.