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991.
Zafar Iqbal J.M. Midgley D.G. Watson S.D. Karditsas G.N. Dutton W. Wilson 《Pharmacy World & Science》1997,19(5):246-250
A method has been developed for the determination of the molecular weight of hyaluronic acid by high performance gel permeation chromatography. The molecular weight distribution was determined using three polymeric columns. Columns were calibrated using Pullulan Polymer molecular weight standards. The average molecular weight (± SD) of the hyaluronic acid in bovine vitreous humour and Healon® were 1.20 ¥ 106 Da (± 0.49 ¥ 106) and 3.01 ¥ 106 Da (± 0.14 ¥ 106), respectively. Furthermore, the depolymerization of the hyaluronic acid in the presence of ascorbic acid (the concentration found in human eye) was studied. Samples incubated in the presence of atmospheric air showed more depolymerization than those where atmospheric air had been flushed-out with nitrogen. 相似文献
992.
993.
994.
Evaluation of a non-breath-hold MR cholangiography technique 总被引:15,自引:0,他引:15
Macaulay SE; Schulte SJ; Sekijima JH; Obregon RG; Simon HE; Rohrmann CA Jr; Freeny PC; Schmiedl UP 《Radiology》1995,196(1):227
995.
996.
G.Jayakrishna Menon Imran Rahman Sharmila J Menon Gordon N Dutton 《Survey of ophthalmology》2003,48(1):58
Visually impaired patients may experience complex visual hallucinations, a condition known as the Charles Bonnet Syndrome. Patients usually possess insight into the unreality of their visual experiences, which are commonly pleasant but may sometimes cause distress. The hallucinations consist of well-defined, organized, and clear images over which the subject has little control. It is believed that they represent release phenomena due to de-afferentation of the visual association areas of the cerebral cortex, leading to a form of phantom vision. Cognitive defects, social isolation, and sensory deprivation have also been implicated in the etiology of this condition. This condition, which is most common in the elderly, frequently goes unrecognized in clinical practice, due to both lack of awareness among doctors and patients' reluctance to admit to hallucinatory experiences, for fear of being labeled mentally unstable. Furthermore, patients who comprehend the unreality of their hallucinations may be distressed by the real fear of imminent insanity. Sensitive and sympathetic history taking is essential to ascertain the existence of hallucinations. Reassurance and explanation that the visions are benign and do not signify mental illness have a powerful therapeutic effect. Hallucinatory activity may terminate spontaneously, on improving visual function or on addressing social isolation. There is no universally effective drug treatment but anticonvulsants may play a limited role in aborting the hallucinations. Physician awareness and empathy are the cornerstones of management. 相似文献
997.
The use of bacteria as test organisms in rapid ecotoxicity assays is under investigation in several laboratories worldwide. However, little attention has been given to the question of permeability of the outer membrane of gram-negative bacteria to toxicants of environmental interest. We have investigated the effect of physical, chemical, and genetic alterations on the sensitivity of Escherichia coli to environmental toxicants, as measured via inhibition of β-galactosidase biosynthesis. Polymyxin treatment (2 mg/L) was the most promising treatment tested, significantly increasing the sensitivity of wild-type E. coli to pentachlorophenol and sodium dodecyl sulfate. A mutant strain of E. coli (EW1b), with an outer membrane protein alteration (tol C gene), was found to be the most sensitive to hydrophobic compounds and to detergent. EW1b, further sensitized via polymyxin treatment, appears to be a sensitive microorganism for toxicant assay. 相似文献
998.
Focal appendicitis confined to the tip: diagnosis at US 总被引:5,自引:1,他引:4
999.
The swift identification of outbreaks of infection is essential for effective control in the population. One of the functions of surveillance is to detect outbreaks but it could be argued that this is one of the weaker aspects of routine surveillance at present. This paper describes a technique which might meet this surveillance need. The CuSum technique allows rapid measurement of change from expected values based on historical data. It is very simple and seems to be a highly sensitive technique which can signal the need for further scrutiny of the data and/or for public health action, long before a change in incidence is apparent from raw data. This is particularly true for low-incidence infections where large fluctuations can make interpretation difficult. CuSums represent a potentially useful adjunct to other surveillance methods in infection control. 相似文献
1000.
Human vascular smooth muscle cells inhibit platelet aggregation when incubated with glyceryl trinitrate: evidence for generation of nitric oxide 总被引:6,自引:4,他引:2
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1. The effect on platelet aggregation of glyceryl trinitrate in the presence of cultured vascular smooth muscle cells was determined turbidometrically. U46619 (a thromboxane mimetic) was used as agonist and experiments were performed in the presence of aspirin. Inorganic nitrite production from glyceryl trinitrate by vascular smooth muscle cells was also measured, to provide an indirect index of nitric oxide synthesis. 2. The combination of vascular smooth muscle cells together with glyceryl trinitrate, at concentrations that had little effect individually, profoundly inhibited platelet aggregation. 3. The inhibitory effect on platelet aggregation of vascular smooth muscle cells together with glyceryl trinitrate was markedly attenuated by haemoglobin, an inhibitor of nitric oxide. 4. These results show that vascular smooth muscle cells inhibit platelet aggregation when exposed to glycerol trinitrate and suggest that this is due to generation of nitric oxide from glyceryl trinitrate by vascular smooth muscle. 相似文献