Left colon gangrene after acute inferior mesenteric artery occlusion

We report here an experience with five patients, aged 58 to 70, suffering gangrene of the left colon after spontaneous inferior mesenteric artery occlusion. All cases were the result of arteriosclerosis; in two, small aortic aneurysms were present and might have been responsible for emboli to the inferior mesenteric artery. The dead bowel was resected in all patients; three patients survived. No primary anastomoses were done and they are not recommended. Because ligation of the patent inferior mesenteric artery has been done so often without ill effects during aortic surgery, the collateral circulation to the left colon can be considered excellent. Gangrene is therefore rare and requires major interference with collateral circulation by emboli or arteriosclerotic occlusion. The clinical symptoms and signs may be confusing.     

Cerebral blood flow changes in cluster headache

Serial cerebral blood flow studies performed by the intra-carotid 133Xenon method were fortuitously determined during the course of a cluster headache in a 32 year old man. The initial study was performed about 10 min after the headache began and showed values at the upper limit of normal. Twenty min after the headache started a second procedure showed that the autoregulatory response on hyperventilation was normal. Ergotamine tartrate was given intra-muscularly 23 min after the headache began and there was partial relief. A third cerebral blood flow estimation showed abnormally high values. The probable reasons for this are discussed.     

Novel injectable urethral bulking agents for the treatment of urinary incontinence

Stress urinary incontinence is a highly prevalent disorder resulting from weak urethral closure mechanisms. Endoscopic injection of a urethral bulking agent (UBA) under the urethral mucosa increases coaptation, which improves continence. Collagen is an efficient agent, although its effects are limited in time. Other materials still suffer either from a short-lasting effect or migration in distant organs. We evaluated here novel UBAs using an ex vivo model, with respect to criteria of ease of injection, ability to form a high and stable tissue bulking, implant elasticity and tissue reaction. One approach involves solutions of polymers in water-miscible organic solvents that precipitates in situ. In this manner, high and stable bulks were routinely obtained using various commercial polymers. Selected solvents reduced the tissue reaction to the implant. Microsphere suspensions in hydrogels also proved to be efficient UBA, although less stable bulks were obtained. Thermosetting chitosan hydrogels showed promising results with respect to bulk stability and isoelasticity with surrounding tissues. Different strategies have thus been compared and optimised ex vivo. Further experiments are required to compare the ability of these materials to induce a sustained in vivo bulking effect.     

Constant-distance mode scanning potentiometry. 1. Visualization of calcium carbonate dissolution in aqueous solution

Constant-distance mode scanning potentiometry was established by integrating potentiometric microsensors as ion-selective scanning probes into a SECM setup that was equipped with a piezoelectric shear force-based tip-to-sample distance control. The combination of specially designed micrometer-sized potentiometric tips with an advanced system for tip positioning allowed simultaneous acquisition of both topographic and potentiometric information at solid/liquid interfaces with high spatial resolution. The performance of the approach was evaluated by applying Ca(2+)-selective constant-distance mode potentiometry to monitor the dissolution of calcium carbonate occurring either at the (104) surface of calcite crystals or in proximity to the more complex surface of cross sections of a calcium carbonate shell of Mya arenaria exposed to slightly acidic aqueous solutions. Micrometer-scale heterogeneities in the apparent calcium activity profiles have successfully been resolved for both samples.     

A developmental study of learned helplessness.

Examined susceptibility to learned helplessness among 20 children from each of kindergarten, Grade 1, Grade 3, and Grade 5 classes by exposing groups of Ss to either repeated failure or repeated success on hidden figures problems. Helplessness was measured by Ss' persistence in looking for hidden figures and their capacity to find them following repeated success or failure. It was hypothesized that younger Ss would be less susceptible to helplessness than older ones, due to age-related differences in causal attributions for success and failure. Results confirm the hypothesis in that failure, relative to success, had significantly less influence on the level of helplessness in younger Ss' behavior. It is suggested that the development of attributional capabilities during the preschool and early elementary school years has important ramifications for cognitive theories of motivation. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of GABA in the control of thyrotropin secretion in the rat

Various doses of GABA from 0.25 to 5 mumol injected into the third ventricle decrease serum TSH rapidly. The same effect was observed with GABOB (10 mumol), the hydroxylated form of GABA. The inhibitory effect of both of these drugs was prevented by picrotoxin injection (1 microgram). Peripheral injection of GABAergic drugs such as GABOB or AOAA also decreased serum TSH. In vitro, the addition of GABA (from 6.7 . 10(-6) to 6.7 . 10(-4) M) to the incubation medium of hemi-anterior pituitary did not modify the liberation of TSH. To test the physiological role of GABA in the regulation of thyrotropin function the circadian TSH rhythm was used as a model. Both GABAergic inhibitors, picrotoxin (10 microgram/kg b.w.) as well as semicarbazide (150 mg/kg b.w.), induced an increase of the low basal nocturnal level of TSH (centered on the 02.00 h time point) without altering the diurnal peak of TSH. We conclude that GABA has an inhibitory effect on central thyrotropin control via an inhibition of TRH release from the hypothalamus and might be, at least partly, responsible for the low nocturnal levels of serum TSH observed during the circadian physiological rhythm.