Visual evoked potentials in the forebrain of the pigeon

Summary The telencephalon of anaesthetized pigeons was systematically explored for flash evoked potentials. A short latency projection to the hyper striatum was confirmed. A second short latency projection which appears to have a major focus in the medial sector of the neostriatum caudale and a more diffuse representation in the remainder of this structure was also found. Longer latency responses were found in a band of tissue surrounding the ectostriatum although the latency of these potentials was too short to be compatible with their origin in a projection from the thalamic nucleus rotundus. The core of the ectostriatum was not responsive under the conditions of the present study. A previously reported projection to the avian archistriatum was not confirmed and evidence is presented that supposed evoked potentials in this region of the brain were confused with volume conducted electroretinograms. All forebrain evoked potentials were attenuated by repetition rates above 1 hz. The origin of these projections is discussed in conjunction with evoked potentials recorded at lower levels of the pigeon's visual system under the same conditions and in the light of available anatomical and electrophysiological evidence. It is concluded that the information about visual projections to the avian forebrain is as yet too incomplete to be useful as evidence for presumptive avian-mammalian forebrain homologies.     

Nucleus striae terminalis lesions affect agonistic behavior of pigeons

Bilateral lesions of the nucleus striae terminalis suppressed the aggressive behavior shown by selected pigeons in response to a stick or the experimenter's hand being introduced into their home cage. Sham-operated animals did not show such an effect. Larger, accurately placed lesions led to an immediate suppression, smaller, less precisely placed lesions to a delayed effect. The suppression of aggression was accompanied by an increase in avoidance responses. The results are discussed in relation to suspected endocrinal activity of the nucleus striae terminalis and to the function this structure has in mammals.     

Phase II trial of weekly 24-hour infusion of gemcitabine in patients with advanced gallbladder and biliary tract carcinoma

Background  

Patients with advanced gallbladder and biliary tract carcinoma face a dismal prognosis, as no effective palliative chemotherapy exists. The antitumor effect of gemcitabine is schedule-dependent rather than dose-dependent. We evaluated the activity of a prolonged infusion of gemcitabine in advanced gallbladder and biliary tract carcinomas.     

Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis

Background  

We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres.     

Behavioral sensitization to apomorphine in pigeons (Columba livia): blockade by the D1 dopamine antagonist SCH-23390

Repeated administration of apomorphine leads to a context-dependent pecking response sensitization. Previously sensitized pigeons (Columba livia) challenged with saline in the same context show a conditioned response (CR). The authors studied the effects of intrastriatal injections of the dopamine (D(1)) antagonist SCH-23390 on both the sensitized response and the CR. When coadministered with apomorphine, SCH-23390 inhibited the initial response to apomorphine, prevented the development of sensitization, and impaired the maintenance of an already developed sensitization. However, SCH-23390 had no effect on the retrieval of a previously established CR. It is concluded that the activation of D(1) receptors in the caudal avian striatum is necessary for the acquisition and maintenance of the sensitization, but not for the expression, of the CR.     

唐古特大黄提取物不同成分泻下作用的比较研究

目的：研究唐古特大黄提取物不同成分的泻下作用。方法：采用炭末推进方法、酚红排空方法进行肠推进实验,观察大黄提取物各成分(15 g·kg^-1)对小鼠小肠推进和肠水分吸收、大鼠大肠运动的影响。结果：唐古特大黄提取物不同成分与对照组相比,对小鼠小肠推进和肠水分吸收、大肠推进作用均有显著性差异(P<0.01)；与大黄水煎液、醇提液相比,泻下活性存在一些差异。结论：唐古特大黄提取物不同成分均有显著的泻下作用,但与大黄水煎液和醇提液相比有一些差异。     

Coralline hydroxyapatite bone graft substitutes: preliminary report of radiographic evaluation

A new bone graft substitute made by conversion of the calcium carbonate exoskeleton of reef-building sea coral into hydroxyapatite has recently become clinically available. The normal radiographic appearance of two forms of this material is described. In the immediate postoperative period, the exoskeletal architecture of these implants is readily appreciated. With graft incorporation over the ensuing months, their intrinsic structure is gradually lost in association with poor marginal definition. Evolving radiographic findings reflect the biocompatible nature of these implants, which provides the potential for ingrowth of native bone with preservation of the coralline scaffold, resulting in enhanced biomechanical properties.     

Myocardial infarct size quantification by MR imaging early after coronary artery occlusion in dogs

The feasibility of using magnetic resonance (MR) imaging to estimate myocardial infarct size was explored in an in vitro model using only the inherent differences in contrast between infarcted and noninfarcted myocardium. Eight dogs underwent coronary occlusion; their hearts were removed 6 hours later. Estimates of T2 for normal and infarcted myocardium were derived from MR images. Infarct size was quantified anatomically using triphenyltetrazolium-chloride (TTC) staining and compared with MR estimates. The T2 values derived from the images clearly discriminated between infarcted (126 +/- 22 msec) and normal myocardium (88 +/- 10 msec, P less than .05), providing images with good contrast between normal and infarcted myocardium. Comparable differences in T2 values were also noted from spectrometric determinations. Estimates of infarct size by MR imaging compared well with TTC estimates (r = 0.98) over a wide range of infarct sizes from 3% to 29% of the left ventricular mass. These results suggest the potential for in vivo quantification of infarct size based on the inherent contrast difference between infarcted and normal myocardium.