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931.
Role of mitochondrial dysfunction and oxidative stress in the pathogenesis of selective neuronal loss in Wernicke’s encephalopathy 总被引:4,自引:0,他引:4
Thiamine deficiency results in Wernicke’s encephalopathy and is commonly encountered in chronic alcoholism, gastrointestinal
diseases, and HIV AIDS. The earliest metabolic consequence of thiamine deficiency is a selective loss in activity of the thiamine
diphosphate-dependent enzyme α-ketoglutarate dehydrogenase (α-KGDH), a rate-limiting tricarboxylic acid cycle enzyme. Thiamine
deficiency is characterized neuropathologically by selective neuronal cell death in the thalamus, pons, and cerebellum. The
cause of this region-selective neuronal loss is unknown, but mechanisms involving cellular energy failure, focal lactic acidosis,
and NMDA receptor-mediated excitotoxicity have classically been implicated. More recently, evidence supports a role for oxidative
stress. Evidence includes increased endothelial nitric oxide synthase, nitrotyrosine deposition, microglial activation, and
lipid peroxidation. Reactive oxygen species production results in decreased expression of astrocytic glutamate transporters
and decreased activities of α-KGDH, resulting in an amplification of cell death mechanisms in thiamine deficiency. 相似文献
932.
Zinc-deficient sprouting blight potatoes and their possible relation with neural tube defects 总被引:2,自引:0,他引:2
Maternal nutritional zinc deficiency is blamed in the pathogenesis of neural tube defects. In animal and plant domains zinc is required for growth and development. The objective of the present study was to show that sprouting blighted potato tuber is zinc deficient. In five potato varieties, zinc was measured by atomic absorption spectrophotometry in wet-ashed paired slices of edible potato tuber and in its peel, in blighted potato tuber and in its sprout. Zinc contents were measured as the mean (+/- SEM) and the following values were found, 0.388 +/- 0.036, 0.623 +/- 0.059, 0.550 +/- 0.030 and 1.089 +/- 0.181 mg per 100 g wet weight, respectively. In conclusion, we believe that long-term consumption of zinc-depleted, blight potato tuber by pregnant woman could be potentially teratogenic with the consequent birth of a baby with neural tube defects. 相似文献
933.
* The incidence of species that develop specialised 'dauciform' lateral roots, which are hypothesised to be important for phosphorus (P) acquisition, is uncertain. We investigated their occurrence in Australian reed, rush and sedge species, grown at low P concentration in nutrient solution, and studied the response of Schoenus unispiculatus (Cyperaceae) to a range of P concentrations. * We assessed the fraction of root biomass invested in dauciform roots, their respiration and net P-uptake rate, and the P status of roots and leaves. * Dauciform-root development occurred only in particular genera of Cyperaceae when grown at low P supply. Increased P supply was associated with increased growth of S. unispiculatus and increased leaf [P]. Dauciform-root growth was reduced by increased P supply, and reduced P uptake co-occurred with the complete suppression of dauciform roots. * The P-induced suppression of dauciform roots in Cyperaceae is similar to that observed for proteoid roots in members of Proteaceae and Lupinus albus. The response of dauciform roots to altered P supply and their absence from root systems of some sedge species are discussed in terms of managed and natural systems. 相似文献
934.
The effects of zinc deficiency and supplementation on plasma leptin levels were studied in Sprague-Dawley rats. After 6 wk
on a zinc-deficient diet containing 0.65 ppm Zn/g, the mean body weight was significantly lower than that of normal or zinc-supplemented
rats, which showed no difference among them. The plasma leptin and zinc levels were lowest in zinc-deficient animals and highest
in those that received a normal diet and daily intraperitioneal injections of 3 mg Zn/kg. These results indicate that zinc
deficiency leads to a significant inhibition in plasma leptin levels, whereas zinc supplementation significantly increases
plasma leptin. 相似文献
935.
Protein energy malnutrition has become a major health issue in developing countries. In the present study, the effect of protein
deficiency on the small intestine and liver tissue content of macroelements and trace elements was investigated in weanling
rats. Forty-five male weanling Wistar albino rats were divided into three groups. The control group (C) was fed a standard
diet containing 25% casein, whereas the two experimental groups E1 and E2 consumed 12% and 3% casein, respectively, over a
period of 45 d. The tissue samples were analyzed for zinc, copper, iron, manganese, calcium, and magnesium by atomic absorption
spectroscopy. The protein-deficient groups showed increased levels of iron in both tissues and decreased manganese in small
intestine tissue from the E1 group. No other differences were found for the other elements. These results suggest that protein
deficiency might cause iron accumulation in the liver and intestine and decreases of manganese in the small intestine. 相似文献
936.
Coulbault L Herlicoviez D Chapon F Read MH Penniello MJ Reynier P Fayet G Lombès A Jauzac P Allouche S 《Biochemical and biophysical research communications》2005,329(3):1152-1154
We describe a lethal mitochondrial disease in a 10-month-old child who presented with encephalomyopathy. Histochemical and electron microscopy examinations of skeletal muscle biopsy revealed abnormal mitochondria associated with a combined deficiency of complexes I and IV. After excluding mitochondrial DNA deletions and depletion, direct sequencing was used to screen for mutation in all transfer RNA (tRNA) genes. A T-to-C substitution at position 5693 in the tRNA(Asn) gene was found in blood and muscle. Microdissection of muscle biopsy and its analysis revealed the highest level of this mutation in cytochrome c oxidase (COX)-negative fibres. We suggest that this novel mutation would affect the anticodon loop structure of the tRNA(Asn) and cause a fatal mitochondrial disease. 相似文献
937.
938.
Lindegaard ML Olivecrona G Christoffersen C Kratky D Hannibal J Petersen BL Zechner R Damm P Nielsen LB 《Journal of lipid research》2005,46(11):2339-2346
Placenta expresses various lipase activities. However, a detailed characterization of the involved genes and proteins is lacking. In this study, we compared the expression of endothelial lipase (EL) and LPL in human term placenta. When placental protein extracts were separated by heparin-Sepharose affinity chromatography, the EL protein eluted as a single peak without detectable phospholipid or triglyceride (TG) lipase activity. The major portion of LPL protein eluted slightly after EL. This peak also had no lipase activity and most likely contained monomeric LPL. Fractions eluting at a higher NaCl concentration contained small amounts of LPL protein (most likely dimeric LPL) and had substantial TG lipase activity. In situ hybridization studies showed EL mRNA expression in syncytiotrophoblasts and endothelial cells and LPL mRNA in syncytiotrophoblasts. In contrast, immunohistochemistry showed EL and LPL protein associated with both cell types. In mouse placentas, lack of LPL expression resulted in increased EL mRNA expression. These results suggest that the cellular expression of EL and LPL in human placenta is different. Nevertheless, the two lipases might have overlapping functions in the mouse placenta. Our data also suggest that the major portions of both proteins are stored in an inactive form in human term placenta. 相似文献
939.
940.
S?ren?HustedEmail author Martin?Ugilt?Thomsen Marie?Mattsson Jan?K.?Schjoerring 《Plant and Soil》2005,268(1):309-317
The influence of various nitrogen (N) and sulphur (S) forms on the uptake of manganese (Mn) in young spring barley (Hordeum vulgare L cv Golf) plants was examined in both a hydroponic system and in a soil-based system. The soil was a typical Danish Mn-deficient soil viz. a sandy loam soil developed on old marine sediments. Plants growing in solution culture with NO3– as the only N source had a higher Mn uptake than plants receiving mixtures of NO3– and NH4+. These findings were opposite to the results obtained in the soil-based experiments, where plants fertilized with NO3– as the only N source accumulated much less Mn than plants fertilized with NH4+. Combining the results of these experiments confirmed that NH4+ acted as a powerful antagonist to Mn2+ during uptake but that this antagonistic effect was more than compensated for by the influence of NH4+ in reducing plant-unavailable Mn(IV) to plant-available Mn(II) in the soil. Furthermore the soil experiments showed that fertilizers containing sulphur in the form of reduced S (thiosulphate) had a strong mobilizing effect on Mn, and enabled the plants to accumulate large amounts of Mn in the biomass compared with oxidized S (sulphate). Thus, fertilization with thiosulphate may be very effective in alleviating Mn-deficiency in soils developed on old marine sediments where Mn availability is limiting plant growth. 相似文献