ISCHAEMIA-REPERFUSION INJURY TO THE INTESTINE

Ischaemia-reperfusion injury (IRI) is of obvious relevance in situations where there is an interruption of blood supply to the gut, as in vascular surgery, or in the construction of free intestinal grafts. It is now appreciated that IRI also underlies the gut dysfunction that occurs in early shock, sepsis, and trauma. The events that occur during IRI are complex. However, recent advances in cellular biology have started to unravel these underlying processes. The aim of this review is to provide an outline of current knowledge on the mechanisms and consequences of IRI. Initially, IRI appears to be mediated by reactive oxygen metabolites and, at a later stage, by the priming and activation of polymorphonuclear neutrophils (PMN). Ischaemia-reperfusion injury can diminish the barrier function of the gut, and can promote an increase in the leakage of molecules (intestinal permeability) or the passage of microbes across the wall of the bowel (bacterial trans-location). Ischaemia-reperfusion injury to the gut can result in the generation of molecules that may also harm distant tissues.     

Calcium Concentration-dependent Mechanisms through which Ketamine Relaxes Canine Airway Smooth Muscle

Background: Ketamine is a potent bronchodilator that, in clinically used concentrations, relaxes airway smooth muscle in part by a direct effect. This study explored the role of calcium concentration (Ca2+) in this relaxation.

Methods: Canine trachea smooth muscle strips were loaded with the fluorescent probe fura-2 and mounted in a spectrophotometric system to measure force and intracellular calcium concentration ([Ca2+]i) simultaneously. Calcium influx was estimated using a manganese quenching technique. Cyclic nucleotides in the airway smooth muscle strips were measured by radioimmunoassay.

Results: In smooth muscle strips stimulated with submaximal (0.1 micro Meter) and maximal (10 micro Meter) concentrations of acetylcholine, ketamine caused a concentration-dependent decrease in force and [Ca2+]i. The sensitivity of the force response to ketamine significantly decreased as the intensity of muscarinic receptor stimulation increased; the median effective concentration for relaxation induced by ketamine was 59 micro Meter and 850 micro Meter for tissue contracted by 0.1 micro Meter or 10 micro Meter acetylcholine, respectively (P < 0.05). In contrast, the sensitivity of the [Ca2+] sub i response did not depend on the intensity of muscarinic receptor stimulation. Ketamine at 1 mM significantly inhibited calcium influx. Ketamine did not significantly increase cyclic nucleotide concentrations.     

Coronary vasomotion in patients with syndrome X: evaluation with positron emission tomography and parametric myocardial perfusion imaging

The aim of this study was to elucidate further the causative mechanism of abnormal coronary vasomotion in patients with syndrome X. In patients with syndrome X, defined as angina pectoris and documented myocardial ischaemia during stress testing with normal findings at coronary angiography, abnormal coronary vasomotion of either the micro- or the macrocirculation has been suggested as the causative mechanism. Accordingly, we evaluated endothelial function, vasodilator reserve, and perfusion heterogeneity in these patients. Twenty-five patients with syndrome X (definitely normal coronary arteriogram, group A), 15 patients with minimal coronary artery disease (group B) and 21 healthy volunteers underwent [¹³N]ammonia positron emission tomography at rest, during cold pressor stimulation (endothelial function) and during dipyridamole stress testing (vasodilator reserve). Heterogeneity of myocardial perfusion was analysed by parametric polar mapping using a 480-segment model. In both patient groups, resting perfusion was increased compared to the normal subjects: group A, 127±31 ml·min^–1·100 g^–1; group B, 124±30 ml·min^–1·100 g^–1 normal subjects, 105±21 ml·min^–1·100 g^–1 (groups A and B vs normals,P<0.05). These differences were abolished after correction for rate-pressure product. During cold pressor stimulation, the perfusion responses (ratio of cold pressor perfusion to resting perfusion) were similar among the patients and the control subjects (group A, 1.20±0.23; group B, 1.24±0.22; normal subjects, 1.23±0.14). Likewise, during dipyridamole stress testing, perfusion responses were similar among the three groups (group A, 2.71±0.67; group B, 2.77±1.29; normal subjects, 2.91±1.04). In group A the heterogeneity of resting perfusion, expressed as coefficient of variation, was significantly different from the volunteers (20.1±4.5 vs 17.0±3.0,P<0.05). In group B (coefficient of variation 19.4±3.9) the difference from normal volunteers was not significant. In this study, patients with syndrome X and patients with minimal coronary artery disease showed normal perfusion responses during cold pressor stimulation and dipyridamole stress testing. Our findings therefore suggest that endothelial dysfunction and impaired vasodilator reserve are of no major pathophysiological relevance in patients with syndrome X. Rather, other mechanisms such as increased sympathetic tone and focal release of vasoactive substances may play a role in the pathogenesis of syndrome X.     

Diagnosing intramuscular myxoma by fine-needle aspiration: A multidisciplinary approach

The gross and microscopic appearances of aspirates from ten intramuscular myxomas are reported. The specimens were obtained from seven women and three men, ages 43 to 75, who had tumors involving the muscles of the thigh (7), upper arm (2), and forearm (1). Magnetic resonance (MR) imaging performed in six of the ten cases revealed well-defined, sharply demarcated tumors exhibiting low signal intensity relative to muscle on the T1-weighted images. The tumors were hyperintense to muscle on T2-weighted images. All aspirated tissues were clear, tenacious, and viscous. Smears contained few spindled and histiocytoid cells in an abundant mucoid background. Spindle cells demonstrated long cytoplasmic processes that in areas intertwined to form fibrillar tangles. Nuclei were oval to spindled with fine chromatin and inconspicuous nucleoli. Capillaries were sparse with simple (nonplexiform) branching. The differential diagnosis of myxoid lesions of the extremities includes benign entities such as myxoid schwannoma and neurofibroma, mesenchymal repair, and ganglion cyst, as well as malignant neoplasms such as myxoid liposarcoma, fibrosarcoma, malignant fibrous histiocytoma, and extraskeletal chondrosarcoma. The findings of this study revealed that, although the cytologic features were suggestive of intramuscular myxoma, a definitive diagnosis was often difficult, owing to scant cellularity and lack of distinctive cytologic features. The MR imaging findings may be utilized as an adjunct to the cytologic features to more confidently suggest a diagnosis of intramuscular myxoma. Diagn Cytopathol 1994;11:255–261. © 1994 Wiley-Liss, Inc.     

Studies of the effects of dietary zinc on the immune organs and cellular immunity in the rat

ＳｔｕｄｉｅｓｏｆｔｈｅｅｆｆｅｃｔｓｏｆｄｉｅｔａｒｙｚｉｎｃｏｎｔｈｅｉｍｍｕｎｅｏｒｇａｎｓａｎｄｃｅｌｌｕｌａｒｉｍｍｕｎｉｔｙｉｎｔｈｅｒａｔＷｕＪｉａｈｕｉ（吴嘉惠）；ＷｕＳｈｕｉｂｉｎｇ（吴水冰）；ＢａｉＪｉａｓｉ（白家驷）；ＫｏｎｇＸ...     

Smooth muscle relaxant effect of dehydroindicolactone

Dehydroindicolactone, a novel linear furanocoumarin with an 8-substituted side chain carrying a 5-member ring lactone, showed spasmolytic activity in a number of smooth muscle preparations. The spasmolytic activity seems to lie in its ability to block the dihydropyridine-sensitive calcium channel.     

Horner syndrome

Horner syndrome is an uncommon but important clinical entity, representing interruption of the sympathetic pathway to the eye and face. Horner syndrome is almost always diagnosed clinically, though pharmacological testing can be used to confirm the diagnosis. Imaging modalities such as PET, CT and MRI are important components of work‐up for patients presenting with acquired Horner syndrome. Our patient’s presentation with Horner syndrome unmasked the causative superior sulcus squamous cell carcinoma and a coincidental lower lobe adenocarcinoma. Successful radical treatment of these cancers resulted in complete resolution of the syndrome and disease‐free survival at 18 months. We review the anatomy and pathophysiology underlying this and other causes of Horner syndrome.     

痛力克对癌症疼痛镇痛效果的临床观察

应用印度ＬＵＰＩＮ公司提供的痛力克（酮酷酸氨丁三醇 ）对中重度癌症疼痛３０例进行镇痛效果的临床观察，有效率９３％，平均显效时间９ｍｉｎ，均数缓解时间５．１ｈ，并用哌替啶做了同期交叉自身镇痛对比研究，结果表明：两药的镇痛效果相似（Ｐ＞０．０５），但痛力克的不良反应发生率明显低于哌替啶。     

必须重视中药新药质量标准和制剂稳定性的研究

从审评工作的角度,提出我国要研制出在世界上有竞争力、安全有效的中药新药,必须重视中药新药质量标准和制剂稳定性的研究。同时,应加强新药审批办法的学习,以提高中药新药的申报水平。