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701.
WN Khan A Nilsson E Mizoguchi E Castigli J Forsell AK Bhan R Geha P Sideras FW Alt 《Canadian Metallurgical Quarterly》1997,9(3):395-405
Septicemia in crustaceans may occur occasionally due to Gram-negative opportunistic bacteria, especially under conditions of intensive aquaculture. The lipopolysaccharide (LPS) endotoxin induces in mammals septic shock and the activation by LPS of hormone release through the hypothalamo-pituitary axis is well known. In crustaceans an increase in circulating Crustacean hyperglycemic hormone and hyperglycemia are reported to result from exposure to several environmental stressors but the metabolic and hormonal effects of LPS in vivo are undescribed. A sublethal dose of LPS (Sigma, Escherichia coli 0111:B4) was injected into at least five individuals of species representative of crustacean taxa and life habits: Squilla mantis (Stomatopoda); the Decapoda Crangon crangon and Palaemon elegans (Caridea), Nephrops norvegicus (Astacidea), Munida rugosa and Paguristes oculatus (Anomura), Pilumnus hirtellus, Macropipus vernalis, Parthenope massena, and Ilia nucleus (Brachyura). Within 3 hr an increase in blood sugar developed ranging from 26.00 +/- 8.37 sd mg/dl in M. rugosa to 201.50 +/- 95. 91 sd mg/dl in P. oculatus and a significant increase of 79% in M. rugosa up to 1300% in P. hirtellus over control levels was observed. The involvement of eyestalk hormones in this generalized response was tested on S. mantis, M. vernalis, and P. elegans; LPS injected into eyestalkless animals did not elicit a significant hyperglycemic response compared with saline-injected controls. Eyestalkless animals injected with one eyestalk equivalent homogenate in saline from untreated animals did show a change in color from red to normal likely due to red pigment concentrating hormone and a hyperglycemic response within 2 hr. Eyestalkless animals injected with homogenate from LPS-treated shrimps showed the change in color but not the hyperglycemic response. It is concluded that LPS directly, or cytokines circulated upon challenge by the endotoxin, may act on the medulla terminalis X-organ-sinus gland complex and release CHH selectively eliciting an hyperglycemic stress response, after which CHH stores become relatively depleted. 相似文献
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This paper examines barriers to communication in telephone traffic. It is found that telephone communication between The Netherlands and most other European countries is about 30% of the level it would achieve if these countries happened to be regions in the same nation. For communication with Eastern Europe, the even smaller figure of about 4% resulted. It is also shown that telephone calls are closely related to other kinds of spatial interaction, especially trade flows. 相似文献
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FW Zonneveld JM Vaandrager JH van der Meulen L Koornneef 《Canadian Metallurgical Quarterly》1998,36(6):1261-79, xii
Three-dimensional imaging of the orbit and its adnexa provides an excellent topographic visualization of the deformity or tumor extent. This helps comprehension, communication, education, and documentation in the process of treating the patient. This article briefly describes the technique of three-dimensional imaging and classifies congenital orbital deformities which are extensively illustrated with relevant case material. 相似文献
708.
The plasma lipoprotein distribution of free nystatin (Nys) and liposomal nystatin (L-Nys) in human plasma samples with various lipoprotein lipid and protein concentrations and compositions was investigated. To assess the lipoprotein distributions of Nys and L-Nys, human plasma was incubated with Nys and L-Nys (equivalent to 20 microg/ml) for 5 min at 37 degreesC. The plasma was subsequently partitioned into its lipoprotein and lipoprotein-deficient plasma fractions by step-gradient ultracentrifugation, and each fraction was analyzed for Nys content by high-pressure liquid chromatography. The lipid and protein contents and compositions of each fraction were determined with enzymatic kits. Following the incubation of Nys and L-Nys in human plasma the majority of Nys recovered within the lipoprotein fractions was recovered from the high-density lipoprotein (HDL) fraction. Incorporation of Nys into liposomes consisting of dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol significantly increased the percentage of drug recovered within the HDL fraction. Furthermore, it was observed that as the amount of HDL protein decreased the amounts of Nys and L-Nys recovered within this fraction decreased. These findings suggest that the preferential distribution of Nys and L-Nys into plasma HDL may be a function of the HDL protein concentration. 相似文献
709.
W. J. Rietveld Richard C. Schlesinger Kenneth J. Kessler 《Journal of chemical ecology》1983,9(8):1119-1133
Black alder trees were interplanted with black walnut on a 2.4 × 3.7-m spacing at four locations in Illinois and Missouri. In every plantation, the alders suddenly declined and died after 8–13 years. Alternative causes for the mortality were investigated–competition from walnut, adverse soil properties, frost, insects, disease, unsuitable seed source, and allelopathy—but only allelopathy could be substantiated. The decline in alder survival and diameter growth was strongly related to walnut above-ground dry biomass and walnut crown competition factor. We propose that the black walnut allelopathy most likely results from a combination of (1) sufficient walnut biomass to contribute substantial amounts of juglone to the environment, and (2) wet soil that greatly restricts aerobic metabolism by soil microorganisms, allowing juglone to build up to toxic levels. 相似文献
710.
Neocortical cultures were deprived of oxygen and glucose to model ischemic neuronal injury. We used a graded series of periods of oxygen and glucose deprivation, providing graded insults. Cell death was measured by release of lactate dehydrogenase (LDH). One hundred and twenty to 240 min of deprivation caused graded increases in glutamate overflow, LDH release and 45Ca influx. Curves of LDH release with respect to deprivation time were shifted to longer intervals by treatment with tetrodotoxin (TTX; 3, 30 or 300 nM), phenytoin (10, 30 or 100 microM), lidocaine (10, 30 or 100 microM) or the N-methyl-D-aspartate antagonist CPP [3(2-carboxypiperazine-4-yl)propyl-1-phosphonic acid, 3, 10, 30 or 100 microM]. Combined treatment with TTX and CPP caused pronounced rightward shifts of LDH deprivation curves. Our results indicate that Na+ channel blockade is neuroprotective in neocortex cultures. Our results also suggest that neuroprotection with Na+ channel blockers may be due to inhibition of glutamate release. 相似文献