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91.
Structural studies of pig heart malate dehydrogenase 总被引:5,自引:0,他引:5
92.
Elevated levels of butyrylcholinesterase activity occur under a number of hypertriglyceridemic conditions, including diabetes
and obesity. This study examines whether butyrylcholinesterase activity has a direct effect on triglyceride production, using
Caco-2 cells, a human intestinal adenocarcinoma cell line. Caco-2 cells were incubated with 500 μM oleate to stimulate triglyceride
production, and butyrylcholinesterase activity was measured in the cellular homogenate. Butyrylcholinesterase activity was
approximately 3 × 10-3 mmol/min per milligram protein. Although triglyceride production increased by almost five-fold after 18 h of stimulation
with oleate, butyrylcholinesterase activity was not increased. Furthermore, inhibition of butyrylcholinesterase activity using
1 mM tetraisopropylpyrophosphoramide did not significantly affect triglyceride production or secretion. Human insulin (100
μU/ml) increased the production of butyrylcholinesterase without increasing triglyceride production. This demonstrates that
stimulation of fatty acid production and butyrylcholinesterase activity occur by independent mechanisms and suggests that
their correlation in hyperlipidemic conditions is not due to a direct relationship in production in situ.
Received 23 April 2001; received after revision 25 May 2001; accepted 20 June 2001 相似文献
93.
Mayhew and Longuet-Higgins have recently outlined a computational model of binocular depth perception in which the small vertical disparities between the two eyes' views of a three-dimensional scene are used to determine the 'viewing parameters' of fixation distance (d) and the angle of asymmetric convergence of the eyes (g). The d/g hypothesis, as it has been called, correctly predicts that a fronto-parallel surface, viewed with a vertically magnifying lens over one eye, should appear to be rotated in depth about a vertical axis. We report here a comparable illusion for surfaces specified by monocular motion parallax information, which can be explained more simply by considering the differential invariants of the optic flow field. In addition, our observations suggest that the disparity-induced effect is not a 'whole field' phenomenon nor one limited to small magnification differences between the eyes. 相似文献
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97.
Satellite imagery in the study and forecast of malaria 总被引:15,自引:0,他引:15
More than 30 years ago, human beings looked back from the Moon to see the magnificent spectacle of Earth-rise. The technology that put us into space has since been used to assess the damage we are doing to our natural environment and is now being harnessed to monitor and predict diseases through space and time. Satellite sensor data promise the development of early-warning systems for diseases such as malaria, which kills between 1 and 2 million people each year. 相似文献
98.
Senile dementia of the Alzheimer's type can be diagnosed with certainty only by examining neurofibrillary tangles and neuritic plaques under the microscope. Recently, it has been suggested that the condition is linked to specific neurotransmitter systems, with a decline of cortical acetylcholine, choline acetyltransferase, cholinergic neurones projecting to the cortex, cortical noradrenaline content, locus coeruleus neurones and cortical somatostatic content. Using immunocytochemical methods, we here report that somatostatin-immunoreactive processes are present in neuritic plaques in human Alzheimer's specimens. These data, as well as other reports of non-cholinergic changes, strongly imply that Alzheimer's disease cannot be linked exclusively to cortical cholinergic elements, as proposed previously. Rather, our data on plaque and somatostatin co-localization and distribution patterns suggest that Alzheimer's neuropathology may involve primarily the loss of selective cortical neurones that are targets of the implicated transmitter systems and that plaque formation may result from the degeneration of presynaptic and postsynaptic neurites of large projection neurones in layers III and V. Given the neurochemically heterogeneous input to these cells, it is not surprising that several neurotransmitter systems, one of which is somatostatin, are implicated in the pathology of Alzheimer's disease. 相似文献
99.
5-Hydroxyhaemopyrrole lactam, the 'mauve factor' reported in the urine of schizophrenics and porphyrics was found to inhibit electrically-stimulated contractions of guinea-pig ileum only at high concentrations (ID50 = 8.5 mM). This low potency makes it unlikely that the compound can account for neurotoxic effects in human porphyria. 相似文献
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