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1.
Two 5-wk trials using 176 weanling pigs (average initial weight of 8.3 kg and age of 31 d) were conducted to examine the effect of feeding varying levels of dietary Cu from copper sulfate (CuSO4) or a copper lysine complex (CuLys) on performance, mineral stores, serum copper, and serum mitogenic activity. Dietary treatments were 0 (15 mg/kg of Cu in basal diet), 100, 150, or 200 mg/kg of supplemental Cu from CuSO4 or CuLys. Average daily gain and ADFI increased linearly (P < .01) with increasing dietary levels of Cu during wk 1 to 2, 3 to 5, and 1 to 5, with no difference (P > .10) between the Cu sources. Overall gain:feed ratios were not consistently affected by Cu source. Dietary Cu linearly increased liver, kidney (P < .001), and brain (P < .05) concentrations of Cu. In the liver, the linear response to supplemental Cu differed between Cu sources (P < .001); pigs fed 200 mg/kg of Cu from CuLys had the highest concentration of Cu. Serum Cu concentrations increased linearly during wk 1 to 2 (P < .01), 3 to 5, and 1 to 5 (P < .001), with no difference (P > .10) between sources. Serum mitogenic activity increased linearly during wk 1 to 2 and 1 to 5 (P < .05). Growth performance was linearly improved as the dietary level of Cu increased from 15 to 200 mg/kg, with similar responses for both Cu sources. Serum and tissue concentrations of Cu were generally equally affected by the two Cu sources, except liver Cu concentration, which was onefold higher for pigs fed 200 mg/kg of Cu as CuLys.  相似文献   

2.
Developmental changes in growth hormone levels during protein or energy malnutrition was studied in weaned pigs. Three or 4 weeks old pigs from control dams were fed a control diet (18% protein), an energy-restricted diet (18% protein) or a low protein diet (6% protein) for 8 weeks. Energy restriction was achieved by feeding the control diet in amounts that allowed very little growth. After the restriction period, all pigs were fed the control diet ad libitum for another 8 weeks. Blood samples were collected at intervals throughout the experiment and the plasma was analyzed for growth hormone by radioimmunoassay. Post weaning protein deprivation resulted in higher growth hormone levels during the restriction period as compared to control pigs or pigs with a restricted energy intake.  相似文献   

3.
To explain the increased plasma mitochondrial aspartate aminotransferase (mAspAT) observed in alcoholics, we cultured HepG2 hepatoma cells in ethanol. Acute (24 hour) exposure to 0, 20, 40, or 80 mmol/L ethanol produced a dose-dependent (r = .98) increase in mAspAT messenger RNA (mRNA) of < or = thirteen-fold, with no significant change in the cellular content of mAspAT or of several other enzymes. The recovery of mAspAT in the medium over 24 hours of ethanol exposure correlated with both ethanol concentration and with mAspAT mRNA (r = .90), reaching 808% of cellular enzyme content/24 hours at 80 mmol/L. Recovery of all other enzymes studied was < or = 20% of cellular content and unaffected by ethanol. Plasma membrane mAspAT content also correlated with mAspAT mRNA (r = .96) and mitochondrial levels were unchanged. No mitochondrial morphologic abnormalities were observed at any ethanol concentration studied. In cells cultured chronically at 0 to 80 mmol/L ethanol, fatty acid uptake Vmax increased in parallel with plasma membrane expression of mAspAT (r = .98). Cellular triglyceride content was highly correlated with Vmax. Thus, the data suggest that: 1) the increased plasma mAspAT observed in alcoholics may reflect pharmacologic upregulation of mAspAT mRNA and of mAspAT synthesis by ethanol; and 2) increased mAspAT-mediated fatty acid uptake may contribute to alcoholic fatty liver.  相似文献   

4.
CASE REPORT: An 86-year-old woman accidentally ingested a preparation containing zinc and copper sulfate. At ninety minutes after ingestion, the peak plasma concentration was 1979 micrograms/dL for zinc and 209 micrograms/dL for copper, suggesting preferential absorption of zinc. The major complications were gastric and bronchial inflammation due to the corrosive properties of these compounds. Systemic manifestations also developed with cardiovascular failure and renal insufficiency, but the patient made a complete recovery. In addition to symptomatic treatment, chelation therapy with dimercaprol and D-penicillamine was given for 48 h. CONCLUSION: The available clinical and toxicokinetic data do not support the benefits of chelation in addition to supportive therapy.  相似文献   

5.
The effects of different concentrations of thiourea (TU) on the copper cathode polarization behavior in an acidic copper sulfate solution was investigated at 65 °C using potentiodynamic and galvanostatic methods. The results showed that there was a transition current density for each concentration of the fresh TU, below which the TU exhibited a polarizing effect and above which the TU manifested a depolarizing effect on the copper cathode. The depolarizing effect increased with cathodic overpotential. The transition current density increased with TU concentration and decreased with time. Lowering of the electrolyte temperature resulted in diminution of the transition current density considerably. In the modern copper electrorefining conditions (65 °C, 150 to 350 A/m2, and using approximately 1 to 4 mg/dm3 of TU), TU produces only a polarizing effect on the copper cathode.  相似文献   

6.
A study was performed to investigate the effect of environmental temperature and increasing levels of protein in the diet on visceral organ size, digestibility, protein balance and energy metabolism in rats. Thirty-six male Wistar rats, initial body weight 77-80 g, were used in a factorial design consisting of three levels of dietary protein and two environmental temperatures of either 18 or 28 degrees C. Three fish meal-based diets were prepared to contain 91, 171 and 262 g protein (N X 6.25/kg diet). Gas-exchange measurements were made and urine and feces were quantitatively collected. The weights of the visceral organs from rats housed at 18 degrees C were greater (P < 0.05) than those of rats housed at 28 degrees C. The digestibilities of dry matter and protein were not affected by environmental temperature, whereas fat and energy digestibilities were higher (P < 0.05) at 18 degrees C than at 28 degrees C. As the level of protein was increased, the digestibilities of protein, energy and fat increased (P < 0.05). Protein intake and protein retention were higher at 18 degrees C (P < 0.05) than at 28 degrees C and increased (P < 0.05) as dietary protein concentration increased. Apparent biological value was lower (P < 0.05) at 18 degrees C than at 28 degrees C and decreased (P < 0.05) as dietary protein level increased. Heat production as a percentage of metabolizable energy was higher (P < 0.05) for the low protein diet than for the medium and high protein diets. The efficiency of energy utilization was depressed (P < 0.05) for the high protein diet when rats were kept at 28 degrees C. The results suggest that thermogenesis was induced when low protein was fed. The increase in thermogenesis may have been important in regulating energy balance and maintaining a constant body temperature in a cold environment.  相似文献   

7.
The diagnosis of neoplasms of the small intestine remains a difficult challenge owing to their nonspecific clinical presentation. CT is an efficient and contributive tool in their diagnosis and preoperative staging. Enabled by CT, the evaluation of the intramural and extramural portions of such tumors complements the mucosal analysis allowed by barium examination. Strict technical rules should be applied to minimize pitfalls mainly resulting from insufficient bowel opacification. Although characteristic appearances are rare, typical CT findings may suggest a specific diagnosis where lipomas and carcinoid tumors are concerned.  相似文献   

8.
A new classification has been proposed for prophylactic antiradiation drugs, which are divided into three groups: radioprotectors, stimulators of radioresistance and the means of protection from internal irradiation. Depending on organs (systems) for the protection of which they are designed, radioprotectors in their turn are subdivided into myelo-, entero- and cerebroprotectors; stimulators of radioresistance (depending on the optimal regimens of their use to develop a higher resistance of the organism) are subdivided into drugs that are effective in single and repeated (course) use; the means of protection from internal irradiation are subdivided into the drugs that prevent incorporation of radioiodine by the thyroid gland, and into the drugs preventing absorption of radionuclides in the digestive tract. The main features that distinguish radioprotectors from stimulators of radioresistance are presented. The former are characterized by such properties as exhibiting the effect exquisitely when prophylactically administered in doses close to those of maximal tolerance, greatest effect against shortterm (pulse) irradiation, rapid development and short duration of the radioprotective action period, reduction in the effect in repeated use, etc. Stimulators of radioresistance rank below radioprotectors in their effect against short-term irradiation, however, unlike the latter, they exhibit their protective effect against a long-term (low dose rate) exposure as well under the conditions of both prophylactic and therapeutic use; their radioprotective action is more prolonged, they are distinguished for their low toxicity and lower the risk of delayed sequelae of irradiation, etc. Examples of the most typical members of each group of prophylactic antiradiation drugs are cited, data are presented which characterize their radioprotective activity, the role and place in the system of antiradiation protection of troops and population.  相似文献   

9.
The objective of this experimental investigation was to obtain information on the reaction kinetics for the hydrogen reduction of copper from copper sulfate solutions in a continuous, countercurrent tubular reactor. Aqueous copper sulfate solution was introduced at the top of the reactor while hydrogen was sparged into the bottom. Separations of the bottom (liquid-solid) and overflow (gas-liquid) products were accomplished in individual high pressure separators. The rate of reaction increases with temperature up to about 180 to 220 °C depending on the residence time and thereafter levels off or decreases slightly. Feed solutions having a pH greater than 1.8 yielded a product which was contaminated with cuprus oxide. Over the range of this study, the operating pressure, and consequently the solubility of hydrogen in the aqueous reactant demonstrated negligible effect on the depletions. Likewise, very little change in depletions was observed beyond residence times of 10 minutes. Acid addition to the feed retarded the rate of reaction, whereas addition of sulfate ion increased the rate; these two observations agree with the results of previous investigators.  相似文献   

10.
Twelve crossbred barrows (initial BW of 59.7 kg) were used in nutrient balance trials to investigate the influence of adding two Bacillus products (Biomate 2B and Pelletmate Livestock, Chr. Hansen's Biosytems) to a 14% CP corn-soybean meal diet (.64% lysine, .6% Ca and .5% P). A 3 x 3 Latin-square design with an extra period was used. Treatments were as follows: 1) basal diet; 2) basal + Biomate 2B (BAC1); and 3) basal + Pelletmate Livestock (BAC2). After a 7-d adaptation to metabolism crates, each 10-d period consisted of 5 d of diet adjustment followed by 4 d of total collection and 1 d for change-over. Both BAC1 and BAC2 were added at a level of .05% to supply approximately 3 million colony forming units per gram of diet. Pigs were fed twice daily at a daily rate of 3.2 to 3.5% of BW. Feeding BAC1 or BAC2 elevated (P < .001) fecal Bacillus spore counts at the end of each collection period, but the effect on number of coliforms and lactic acid bacteria was not as consistent; coliform counts tended to be decreased (P < .10) when BAC2 was fed, but not (P > .10) when BAC1 was fed. The number of lactic acid bacteria was increased (P < .05) when BAC1 was fed, but not (P > .10) when BAC2 was fed. Body weights were similar among all treatments for all periods. There was no carry-over or pretreatment effect (P = .50). Digestibility coefficients of DM, neutral detergent fiber, acid detergent fiber, ash, and N and retention of N were not affected (P = .40) by feeding Bacillus products.  相似文献   

11.
Ninety-six weanling pigs (initial BW = 9.3 kg, initial age = 37 d) were used in a 4-wk experiment to evaluate the response to three Ca: total (t) P ratios (1.2:1, 1.6:1, or 2.0:1) fed in combination with two P levels (.07 or .16% available that correspond to .36 or .45% tP) and two phytase levels (PY; 700 or 1,050 units/kg of diet). A 3 x 2 x 2 factorial arrangement of treatments was employed using a corn-soybean meal diet. Performance, serum mineral concentrations and alkaline phosphatase (ALP) activity, Ca and P digestibility and excretion, and bone mechanical measurements were examined. Average daily gain (P < .001), average daily feed intake (P < .01), and gain:feed (P < .05) were decreased linearly as the Ca:tP ratio became wider. The digestibility of P and Ca were decreased (P < .001) linearly as the Ca:tP ratio became wider. The digestibility of P (P < .001) and fecal P excretion (P < .01) were increased at the higher level of P. Increasing PY from 700 to 1,050 units (U)/kg of diet increased (P < .05) P digestibility and decreased (P < .01) P excretion but did not improve bone measurements. Shear force, stress and energy, and percentage of ash of both metacarpal and 10th rib linearly decreased (P < .001 to .05) as the Ca:tP ratio became wider, and bone measurements were generally greater for pigs fed the higher P level. Serum Ca concentration increased (P < .01) and the P concentration decreased (P < .001) as the Ca:tP ratio increased, but Mg, Zn, and ALP activity were not influenced by the Ca:tP ratio. Serum Ca and P concentrations were affected by PY supplementation over the 4-wk trial, but serum Mg and Zn concentrations were not affected by dietary treatments. Adverse effects of a wide Ca:tP ratio were greater at the low P diet for all responses. In addition, the activity of supplemental PY in diets seemed to be decreased as the Ca:tP ratio became wider and this negative effect of Ca:tP ratio seemed greater at the low P level, and seemed to parallel the effects of Ca:tP ratio on performance, P digestibility, bone, and serum measurements. Narrowing the dietary Ca:total P ratio from 2.0:1 to 1.2:1 led to an approximate 16% increase in phytase efficacy for improving performance, digestibility, bone measurements, and serum Ca levels.  相似文献   

12.
Oxidized low density lipoprotein (LDL) may play a significant role in atherosclerosis. We have investigated the effect of pH on the oxidation of LDL by iron or copper. When LDL was oxidized by iron in the presence of cysteine in either Hanks' balanced salt solution (HBSS) or Ham's F-10 medium, an acidic pH greatly decreased the lag period and increased the rate of formation of hydroperoxides and thiobarbituric acid-reactive substances (TBARS), and increased its uptake by macrophages. There was a dose-dependent increase of LDL oxidation at acidic pH in the presence of increasing concentrations of cysteine. When LDL was oxidized by copper in HBSS, an acidic pH increased the lag phase before the rapid formation of conjugated dienes, hydroperoxides, and TBARS, but increased its uptake by macrophages. Similar results were obtained using Ham's F-10 medium. Cysteine (100 microM) inhibited the modification of LDL by copper in HBSS at both pH 7.4 and 5.5 As atherosclerotic lesions may be acidic, these observations may help to explain why LDL oxidation occurs locally at these sites.  相似文献   

13.
14.
The dopamine (DA) D2/D3 antagonist (-)eticlopride (0.02, 0.05 and 0.1 mg/kg), dose-dependently increased immobility in the mouse tail-suspension test. Chronic treatment with the same compound (0.05, 0.1 mg/kg, x 14 days) produced a different effect, decreasing immobility when animals were tested 24 h after the last injection. The DA D3 agonist, 7-OH-DPAT, acutely administered before the same test, behaved biphasically, increasing and decreasing mice immobility at low (0.05 and 0.1 mg/kg) and high (1 and 2 mg/kg) doses, respectively. Chronically administered 7-OH-DPAT reduced the immobility time at 2 mg/kg but not at 0.1 mg/kg. These effects, coupled with measurements of locomotor activity and evaluation of mice behaviour in different conditions, are discussed in the light of putative DA involvement in depressive states and are considered as predicting antidepressant potential.  相似文献   

15.
The direct hydrogen reduction of metal sulfates may provide an attractive method for producing high-purity metals. In this work the intrinsic kinetics, unaffected by diffusional and mass transfer effects, of the hydrogen reduction of copper sulfate particles have been determined using a nonisothermal technique. The reduction rate shows a first-order dependence on the hydrogen partial pressure and the amount of unreacted copper sulfate. The activation energy of the reaction was determined to be 63.7 kJ/mol. SUN K. KIM, formerly Graduate Student in the Department of Metallurgy and Metallurgical Engineering, University of Utah.  相似文献   

16.
A complex Cu/Zn/Pb ore from Cayeli, Turkey, was reacted with cupric chloride solutions under different conditions. Energies of activation were calculated for dissolution of copper (37 kJ mol?1), iron (33 kJ mol?1, zinc (26 kJ mol?1) and lead (7.5 kJ mol?1, values which indicate diffusion control of the reaction, probably through the sulphur layer formed round each particle. Particle size/leaching relationships corroborated microscopic assessments and indicated that chalcopyrite dissolved at a very low rate. Calculation of Fe:Cu ratios of metal leached showed considerable dissolution of pyrite from finely-ground (d12 ≈ 3?5 μm) ore. Examination of residues using SEM X-ray fluorescence line scan techniques revealed little attack of large pyrite crystals, suggesting that fine pyrite particles in complex relationship with the sphalerite and chalcopyrite were dissolving.  相似文献   

17.
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19.
OBJECTIVES: L-arginine exerts anti-atherosclerotic effects in hypercholesterolaemic rabbits via modulating endogenous NO production. We investigated whether L-arginine inhibits thromboxane formation in vivo and platelet aggregation ex vivo in this animal model. METHODS: The urinary excretion rates of 2,3-dinor-6-keto-PGF1 alpha (major urinary metabolite of PGI2) and 2,3-dinor-TXB2 (major urinary metabolite of thromboxane A2) were used as indicators of platelet-endothelial cell interactions in vivo. Rabbits were fed 1% cholesterol (Cholesterol group, N = 8), 1% cholesterol plus 2.25% L-arginine (Cholesterol + L-arginine, N = 8), or normal rabbit chow (Control, N = 4) for 12 weeks. Urine samples were collected in weekly intervals. At the end of the study period platelet aggregation ex vivo and endothelium-dependent and -independent vascular function of isolated aortic rings in vitro was assessed. RESULTS: Urinary 2,3-dinor-TXB2 excretion significantly increased in the cholesterol group (p < 0.05), and endogenous NO formation (measured as urinary nitrate excretion) decreased (p < 0.05). Both parameters were significantly correlated with each other (R = 0.48, p < 0.01). L-arginine partly restored urinary nitrate excretion and significantly reduced TXA2 production to values even below those in the control group (p < 0.001). Urinary 2,3-dinor-6-keto-PGF1 alpha excretion increased in early hypercholesterolaemia and returned to control values in the second half of the study period. The early increase in urinary 2,3-dinor-6-keto-PGF1 alpha excretion was attenuated by L-arginine. Platelet aggregation was significantly enhanced in cholesterol-fed rabbits and attenuated by dietary L-arginine. L-arginine also improved the impaired endothelium-dependent relaxations to ADP, and normalized the vasoconstrictor effects of 5-HT in isolated aortic rings. CONCLUSIONS: Cholesterol-feeding enhances platelet aggregation and TXA2 formation, and stimulates platelet-endothelial cell interaction in rabbits. These effects are probably due to impaired NO elaboration, as indicated by decreased urinary nitrate excretion. Chronic dietary supplementation with L-arginine elevates systemic NO elaboration and significantly increases the PGI2/TXA2 ratio. It thus beneficially influences the homeostasis between vasodilator and vasoconstrictor prostanoids in vivo.  相似文献   

20.
Zinc metabolism and homeostasis were studied in young growing rats fed a 38 ppm zinc diet with added zinc levels ranging from 0 to 8400 ppm for 21 days. High dietary zinc did not cause toxicity symptoms. Stable zinc in feces increased linearly with dietary zinc intake but fecal 65Zn, from a single oral dose, did not increase above the 1200 ppm dietary level. Stable zinc in liver, kidney, and tibia increased two to three times with 2400 ppm added zinc, but was not further elevated until 8400 ppm was fed. Stable zinc in muscle and heart was not affected appreciably by dietary zinc level. In all tissues, 65Zn retention was drastically reduced with 1200 ppm added dietary zinc. Additional dietary zinc reduced 65Zn in muscle and heart but had little effect on liver and kidney 65Zn. The data indicate that rats have fairly effective homeostatic control mechanisms for tissue zinc below about 7200 ppm dietary zinc. Whereas, with dietary zinc up to about 1200 ppm, decreasing absorption is the main route of homeostatic control, above this level, more rapid zinc turnover rates and increasing endogenous zinc excretion appear to have major importance.  相似文献   

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